# Homemade Controller- What Features?



## Mr. Sharkey (Jul 26, 2007)

Other important features? Like:

Current limiting
RPM limiting
Over current threshold shutdown
Motor over temperature foldback/shutdown
Controller over temperature foldback/shutdown
Interlock ladder inputs
Soft start
Acceleration ramp up
Low battery shutdown
High battery shutdown/lockout

That's what comes to mind quickly. I could probably think of more if you want to make it even more complex.


----------



## Gashog (Dec 23, 2007)

Brushless?


----------



## Greenflight (Sep 13, 2007)

What kind of design have you got so far? I'm (slowly  ) working on my own homebuilt IGBT controller, with a PIC driver and LCD readout so I'm interested in what others are coming up with.

One feature that I'm going to include in my controller is (semi automatic?) throttle endpoint adjustment... That way you don't have to fool around with getting the throttle travel just right.

And I'm thinking you're going to want more than 96v and 400A... It's easy enough to bump it up to maybe 144v or more and 600A, and later on when you want to up the voltage in your EV you won't have to build a new controller.

Also an interface for an RPM sensor would be nice...

And Sharkey... what the heck are interlock ladder inputs?


----------



## TheSGC (Nov 15, 2007)

Right now I have a barebones setup with a 555 timer hooked up to a mosfet for a 9 volt test controller and small motor. Once that is completed, I can rig my my BASIC Stamp controller and add more things, like a digital temperature sensor for the controller and other goodies. I need to find some higher AMP MOSFETS, like 80+ AMPs. MOSFETS can be run in parallel for more AMPs, and I hoping to find parts for a 600 AMP system. Does anyone know of such MOSFETS? I am about to take a look at Digikey.com and see what they have. 

These are great ideas, and many of them I had not even considered. Keep'em coming!


----------



## Mr. Sharkey (Jul 26, 2007)

Building PWM circuits with 555 timer is way too primitive for me, imprecise also. If you want a one-chip solution that can integrate a 0 - 100% duty cycle PWM waveform from a DC control voltage, check out the LM2524 IC from National Semiconductor. I built a very nice controller for my electric tractor out of one of these, a handful of junk box parts, and an old MOSFET board out of a scrapped DC-AC inverter. It includes current limiting and has an integral voltage reference, etc. All for about $2!


----------



## Greenflight (Sep 13, 2007)

Yeah, if I understand correctly, the 555 only provides a duty cycle from like 25-80 percent or something, so it isn't great for high performance motor controllers. I haven't worked with basic stamps, but can't you output a PWM from them? Does it have on chip A/D conversion? You should be able to put the entire driver on one chip...

You can pick up a 600A IGBT on ebay for pretty cheap... Might be a better solution than MOSFETs. I have one, but I'm not exactly ready to use it...


----------



## TheSGC (Nov 15, 2007)

The 555 circuit I have laid out is a 5% to 95%+ duty cycle which seems fine right now, but more would definately be better. I have been looking at the Basic Stamp to do the PWM, but from what I can find it is very taxing on it. I do have a lot of old junk parts that I think I would go through and see what is salvageable.

I wish there was a local store that carried IGBTs and MOSFETS...


----------



## Gashog (Dec 23, 2007)

TheSGC said:


> The 555 circuit I have laid out is a 5% to 95$+ duty cycle which seems fine right now, but more would definately be better. I have been looking at the Basic Stamp to do the PWM, but from what I can find it is very taxing on it. I do have a lot of old junk parts that I think I would go through and see what is salvageable.
> 
> I wish there was a local store that carried IGBTs and MOSFETS...


Are you guys familiar with the Megasquirt? I run my Volvo on one. There's a guy who ran his greenhouse with one. Probably has a lot of useful circuits and firmware/software. I'm sure one of these boxes could do whatever you needed, provided you could tell it what you want.


----------



## Greenflight (Sep 13, 2007)

OK, I'm trying to understand, but I just can't. How can you run a greenhouse off of an EFI controller? Looks pretty cool though...


----------



## Gashog (Dec 23, 2007)

Greenflight said:


> OK, I'm trying to understand, but I just can't. How can you run a greenhouse off of an EFI controller? Looks pretty cool though...


Yeah. It's the coolest! It taught me how to solder, burn a chip, and brought me to a level of patience and self discipline that I thought only Jesus could reach! I was pretty much a headers and cam kind of guy until I found this thing.
A greenhouse is just a big solar powered engine. An EFI controller is only an EFI controller until you tell it to do something else. The code is all open and written in an assembly language that's easy to hack. You can program it any way you want (if you know how to do it). People are controlling transmissions and brakes with it also. I think you could automate your home with it if you wanted. A sharp guy could tell it to charge batteries, run brushless motors, slow the vehicle...Anything.


----------



## Greenflight (Sep 13, 2007)

That's cool. Sounds a lot like the PICs I've been working with, only more specialized. That computer interface looks pretty slick!

PICs are pretty cool too- you can program them to do just about anything (they can be programmed in either assembler or a form of basic with a compiler). Best of all they only cost a few bucks.  They kind of lend themselves to this kind of thing because a lot of them have built-in analog/digital converters and hardware PWM. Now if only I can get mine working... 

Another feature (from another thread) that would be nice to have in a controller would be cruise control. If you have an RPM sensor, it would be really easy to add, and could probably even give you more control than factory cruise control.


----------



## Gashog (Dec 23, 2007)

The MS1 uses the Motorola MC68HC908GP32. (I built two about 5 years ago.)
It's a bit out dated now and the MS2 uses the MC9S12.
Very powerful for the money. My MS1 kits cost about a hundred bucks each and came with a bunch of sandwich bags full of electronics, a PCB and a simple aluminum box to stuff it in. You hacker types should definitely be checking this kit if you haven't already. I'm sure this thing could be the stand alone we need, if it were tweaked to run without gasoline. Mine use FETs to run low-Z injectors through a current limiting resistor pack (like 3 ballast resistors). I'm sure you could run your IGBT's, chargers, inverters and motors closed loop with it. I also built a Megaview. They have a _really _cool one out now but I kinda like my little screen.
Check THIS bad boy out! And it's all open source.


----------



## TheSGC (Nov 15, 2007)

I am getting some high AMP IGBT, 600AMP+ and maybe even 1200 AMPS, but now I am wondering about current control. I am trying to figure out how controllers, like the Curtis, control the current. I am not using a large motor, (ADC K99-4007) and I dont think it can take anymore than 350 AMPS max anyways.

Also, I came up with an idea for cruise control. I found an IC chip in my stash that is actually a digital potentiometer. So I can create a cruise control circuit that connects to the existing POT and takes in the car speed and adjusts the throttle digitally to accelerate/deaccelerate when cruising through hills and such. The idea can be used on any EV with a POTBOX throttle control, which makes it an even better idea.


----------



## Mr. Sharkey (Jul 26, 2007)

In order for a controller to limit current, it must first know how much current there is. This is accomplished by use of a shunt, which generates a voltage that's proportional to the amount of current in the circuit. The shunt voltage is compared to a calibrated reference voltage by a differential amplifier, and when the shunt voltage exceeds a predefined threshold, the controller stops widening the PWM to the output semiconductors, thereby clamping the current at a maximum level.

That circuit is all built into the PWM controller chip I mentioned elsewhere, but it can be built out of discrete components as well.


----------



## Greenflight (Sep 13, 2007)

I've always wondered why controllers with current limiting don't have an output for an amp meter. It would save the trouble of putting a separate shunt into the system. Another feature that goes on the list...

Good idea on the digital pot... That would be a good add-on for existing systems. I still like the idea of having the whole thing integrated into the controller, though.


----------



## Mr. Sharkey (Jul 26, 2007)

Consider not having a throttle pot at all. Some controllers come with the option of using a Hall effect sensor, but there are other methods. The controller in my car uses an optical sensor that reads the position of a small metal flag attached to a shaft inside the controller which is acutated by the accelerator cable. The sensor is mounted on the controller PCB, so there are that many less wires, connectors, and points of failure, not to mention not having the mechanical aspect of a potentiometer to deal with. No pot is going to last forever, and when they get old, they get flaky in the worst sort of way.


----------



## Dan Frederiksen (Jul 26, 2007)

I'm also working on my own controller, I'll post more in detail tomorrow.

two features that would be nice to have in the controller is a 12V DCDC and a recharger.
you might think those are separate issues but actually it makes a lot of sense to have all together

ps. there are components that do current sensing and give you a corresponding 0-5v signal


----------



## Greenflight (Sep 13, 2007)

Yeah, the ideal controller would be an entire car management system in one box. Seems to me AC Propulsion's controller was kinda like that. It really would be the way to go.

I've thought about using a transducer for current sensing, but I decided not to because of two reasons: 1) I don't know anything about them,  and 2) I don't know if they would be suscpetible to interference from all of the electrical noise in an EV. Any thoughts?


----------



## Dan Frederiksen (Jul 26, 2007)

here is a not quite updated schematic of my controller proposal.
it's missing a gate resistor of 1-2Ohm and there is a current sensing component Tamura L01Z600S05 on the wire between the diode and the transistor that gives a 0-5V signal fed into one of the CPU's data inputs (PC1)
some have suggested pull down resistors on the gate and driver signal for safety in failure modes. whether that's actually good or just false sense of security I'm not certain about yet.










otherwise it should have a chance of actually working. 
the idea is that the power section (diode, transistor and cap) can be copied in parallel coupling for greater current rating. (just illustrated once in the diagram)
I might add a diode, inductor and capacitor before the low voltage supply to ensure that it has proper voltage even during short bursts of acceleration where the voltage might otherwise sag below the ~90V minimum that the pwrx module requires

This is a high voltage design (~350V) but the same could be used with 200V mosfets instead of IGBTs for maybe 144V systems.

because a motor in stall is essentially a short circuit, the controller has to start very cautiously looking for any build-up of current with the current sensor. it could fry itself in a tenth of a millisecond but it should be possible to make very short pulses to begin with and see what current that results in. that's a programming issue


----------



## Dan Frederiksen (Jul 26, 2007)

a roughly updated version:


----------



## Greenflight (Sep 13, 2007)

Okay, so, if I understand correctly, your controller doesn't require any 12v input at all? Nice...  I tried searching on that PWRX power supply, but didn't come up with much except obsolete part listings... Is there a newer (equivalent) version of it?

One of the main problems I've been dealing with is how to isolate the high and low voltage supplies so the traction pack doesn't end up grounded to the chassis... A power supply like that would put that issue to rest.


----------



## Dan Frederiksen (Jul 26, 2007)

yes it is completely stand alone but the little module is relatively low power so wont be able to switch too many transistors. it is a bit obscure but shouldn't be obsolete: http://www.pwrx.com/pwrx/docs/m57184n_715b.pdf
unfortunately only rell.com sell them
(you can write digikey and ask them to sell it too. it can work)

eventually I figure a controller should include both the 12V DCDC as well as recharger since they share several connections, specs and components. all 3 are connected to the batteries and all have to match that voltage. they can also share low voltage systems and case.
one system can also better monitor how much power has been drained from the batteries and therefore better know how to recharge them.

I am (very) slowly building a prototype. I am procrastinating in the extreme. I don't have a motor or battery so for the first test I have rectified the 230V AC mains as my source (320V DC unloaded) and 4 halogen 500W worklights as my forgiving load. a resistive load is much easier to handle than a motor so it's a good baby step. so far I have only made the rectifier and the low voltage circuit which both work but still a ways to go


----------



## TheSGC (Nov 15, 2007)

So far my simple controller has the capacity for 100 Volts, and 660 Amps continous with a 2200 AMP peak ratings using IRF540N MOSFETS, which are on order. (eBay is a great place) I am trying to get some IGBTs as free samples, but I have no idea when I will get them, if I can even get them. I am currently buidling the other features, the cruise control, current limiting, low/high voltage shutdown and also a range estimation circuit using pack voltage, current sensing and the basic stamp controller. I'll see how that goes, but I might need a more powerfull microcontroller for more features.


----------



## Greenflight (Sep 13, 2007)

Wow, you guys are working so much faster than I am!  Seriously, I'm getting lots of great info from this thread.

Dan- That converter is a really good deal for 7 bucks... I'll have to order a couple. One question though- the datasheet says it has a minimum voltage of 140, which is a little higher than a lot of systems lag under load. You mentioned a 90v min in one of your other posts... Is that like an instaneous voltage, requiring more to operate continously? Or is the datasheet a little generous?

SGC- so you've got 20 mosfets in parallel? Is there a reason so many controllers (e.g., Curtis, Raptor) use a bunch of parallel mosfets instead of a single IGBT, like forklift controllers? Or is it just cost cutting? Is it high on resistance or something?


----------



## Dan Frederiksen (Jul 26, 2007)

the 140V is a comfortable margin. if you look in the datasheet you can see where the 5 and 15V supplies start to fail and it's around 90V iirc. with a cap to keep the voltage high I figure it should work with 120V systems, maybe less.

as for many small vs one large module that's a cost issue. the large modules are higher priced. much.

one thing I learned relatively late is that the heatsink of the 'small' transistors are electrically active. usually connected to the middle lead. that has to be taken into account in the heat sink solution. two options, either have live heatsinks inside a box (and one heatsink for each electric point) or use socalled heatpads which are expensive and are poor thermal conductors so limit their performance. it would appear that the large transistor modules are not electrically live on the heatsink side, at least the two surplus powerex 1200V 600A modules I have aren't.

for comparison the new price of those is 450$ each. the small 600V '80A' TO-247 transistors I have bought cost around 2$ each. both are IGBTs.

I did buy the two large ones surplus for 25$ each and it seems it's a very prolific model but even at that spectacular price they are still not decisively less expensive and newer transistors can be more efficient.


----------



## TexomaEV (Jul 26, 2007)

I like Hazen's symetrical designed controller. Apparently it's pretty good at keeping everything cool also:

www.evhelp.com/Controller_Prototype.htm


Don't forget to read the magazine article that wrote about it, the link is at the bottom of the prototype page. 

Is this he a member of DIYElectricCar ?


----------



## Dan Frederiksen (Jul 26, 2007)

I get the idea about disc symmetry but I think it's maybe more of a gimmick than actually significantly beneficial. he doesn't show a controller circuit does he? and he doesn't seem to mention freewheeling diodes either which I thought was a significant element in a motor controller. I guess he has that covered. I can ask him.


----------



## TheSGC (Nov 15, 2007)

I also realized that the MOSFETs share there heatsink with pin 2, but that ends up being the Drain pin, so it should work fine with my controller if I keep all the MOSFETs on the same heatsink, and if that heatsink conducts electricity, I will connect it to the Drain wires that go to the motor for the best connection.

The MOSFETS were definately cheaper, only $10 on eBay compared to the $200 equivalent IGBT. The resistance on them is related to the temperature, and I plan on having these on a nice fan cooled heatsink, and maybe even watercooled.


----------



## Greenflight (Sep 13, 2007)

Okay I get it now... Should work great for the voltage I'm working with.

I have one of those surplus PRX 600A IGBTs also. I think I paid roughly 25 bucks for it. There's an endless supply of them available on ebay.


----------



## Mr. Sharkey (Jul 26, 2007)

TheSGC said:


> if I keep all the MOSFETs on the same heatsink, and if that heatsink conducts electricity, I will connect it to the Drain wires that go to the motor for the best connection.


There's no reason to insulate the MOSFET tabs from the heat sink, assuming that you insulate the heat sink itself electrically -however- using the heat sink itself as the current conductor is not a good idea. Most heat sinks will have a light anodized coating which will be an electrical insulator and prevent the MOSFETs from properly contacting for good electrical transfer.

I have repaired many high power inverters and power supplies that use discrete MOSFET devices, and the preferred method is to place a copper bus bar on top of the tabs of the MOSFETs before fastening them down to the heat sink. It's a simple matter to drill the bus to accept the machine screws and provide clamping action that's more than adequate for current conduction.


----------



## TheSGC (Nov 15, 2007)

Oh that's good that I don't have to do anything to the MOSFETs if I put them all on the heatsink and just use the pins. What would be a good size heatsink for this? I was thinking of a 6 inch by 10 inch size thing with dual fans, and it would end up being the top of the whole controller. Something like a ginormous Pentium II heatsink from back in the day, just with holes for screwing the MOSFETs to it and two maybe even three CPU fans.


----------



## Dan Frederiksen (Jul 26, 2007)

depending on your design, diodes will need to be on a different heatsink because their backs are live too and usually not the same circuit point


----------



## Greenflight (Sep 13, 2007)

This guy sells really nice heatsinks... http://search.ebay.com/_W0QQsassZbarrredboss

I bought one of them. I think it should be big enough for most applications... The heat sink on my Raptor (rated for 600A continuous  ) isn't all that much bigger, and it only has one fan on the end of the controller.


----------



## Dan Frederiksen (Jul 26, 2007)

yeah I've bought a couple of those too 
surprisingly few online sources of heatsinks it seems


----------



## TheSGC (Nov 15, 2007)

I have most of my prototype done, all that is left at the moment is programming the Basic Stamp to work with all the attachements and to mount the MOSFETs to heatsinks. I also haven't quite finished the current limiting except for using a fuse that will blow at 500 AMPS. I have acquired 19 Intel Xeon heatsinks that a local company were throwing out, and I am using six of them for the MOSFETs. There must be 40lbs of copper from all of them, so using only 6 should be enough for the 20 MOSFETs. (IRF540N)


----------



## Dan Frederiksen (Jul 26, 2007)

don't you have diodes to cool too?


----------



## TheSGC (Nov 15, 2007)

Dan Frederiksen said:


> don't you have diodes to cool too?


I have completely forgot the diodes! I have only been doing testing on a small 12 V motor so I did not attach the diodes yet, but I have them. I have been losing my mind over programming this thing to do exactly what I want. I have to do a number of conversions of the input data so they all work nicely together.

Whoever invented this programming language left out common sense as part of it.....


----------



## Dan Frederiksen (Jul 26, 2007)

I have chosen an atmega8 microcontroller with an arduino board to program it. it's my impression that it's reletively easy to program it


----------



## xrotaryguy (Jul 26, 2007)

Greenflight said:


> This guy sells really nice heatsinks... http://search.ebay.com/_W0QQsassZbarrredboss
> 
> I bought one of them. I think it should be big enough for most applications... The heat sink on my Raptor (rated for 600A continuous  ) isn't all that much bigger, and it only has one fan on the end of the controller.


You're using that heat sink on your IGBT then right? You haven't decided to use use MOSFETS have you?

This is a great discussion. I think that I am going to go ahead and build my own controller as well. Considering how cheap and time potentially consuming it is, I will probably build the controller before the rest of the car. I have a 24v electric bike or a 36v motor on which to test.


----------



## xrotaryguy (Jul 26, 2007)

Dan Frederiksen said:


> yes it is completely stand alone but the little module is relatively low power so wont be able to switch too many transistors. it is a bit obscure but shouldn't be obsolete: http://www.pwrx.com/pwrx/docs/m57184n_715b.pdf
> unfortunately only rell.com sell them
> (you can write digikey and ask them to sell it too. it can work)
> 
> ...


Another potential issue with this power converter is that it only works down to 140vdc, so for people funning less than 12 12v batteries, it might not work. No forklift motors please


----------



## Dan Frederiksen (Jul 26, 2007)

it is a little weak and has a relatively high lower voltage limit yes but reading the spec sheet a bit closer you can see it can operate all the way down to 90V so I figure 120v should be ok albeit maybe with a diode and cap on its supply so that hard bursts of power doesn't shut it down from voltage sag. 120v could sag to 60 in a sprint.


----------



## xrotaryguy (Jul 26, 2007)

Mr Fredriksen,

That Tamura current sensor... is that device basically the same thing as the inductive pick-up that a timing light might use? I am just curious. I am not considering cutting the inductive unit off of my timing light 

Oh, and back to the power converter that you're using (I know, I know, get over the power supply bub!) I would still be concerned that the power supply could fail in certain conditions. For instance if the pack were down to 100vdc and the weather was either very hot or very cold, I would be concerned that it would fail. Or, if one of the batteries in the traction pack stopped working properly and voltage dropped too far... Also, the motor's inductance combined with the high speed switching of the IGBT could cause problems for the converter... especially if it is being asked to operate outside of its recommended envelope. I just wanted to throw that out there. I wonder if a power converter exists that is designed to work at voltages more similar to those that an EV typically uses. I have done some searching for such a thing and have only found units that are considerably more expensive than your Powerex.


----------



## Dan Frederiksen (Jul 26, 2007)

it would also fail if the car got hit by a shell from an abrams tank or a nuclear blast or a direct hit from a medium sized meteor going 100km/s. but it's no reason to change the design.


----------



## xrotaryguy (Jul 26, 2007)

picky picky


----------



## Dan Frederiksen (Jul 26, 2007)

the tamura is not inductive I think. it is magnetic but it has to measure DC current and that doesn't induce. it's probably a hall probe.

the DCDC can fail if too little voltage during hard accel and that can be handled with a diode and a cap so it stays high for the sprint. that is a genuine consideration for 'low' voltage systems. there might be other dynamic issues too. I'm not an EE, I just read a chapter in a book


----------



## xrotaryguy (Jul 26, 2007)

Dan Frederiksen said:


> the tamura is not inductive I think. it is magnetic but it has to measure DC current and that doesn't induce. it's probably a hall probe.
> 
> the DCDC can fail if too little voltage during hard accel and that can be handled with a diode and a cap so it stays high for the sprint. that is a genuine consideration for 'low' voltage systems. there might be other dynamic issues too. I'm not an EE, I just read a chapter in a book


I'm no EE either. I did recently change my mojor to EE though, so perhaps there is hope for me yet. Thanks for doing the reading for me though.  I will do more of my own reading when my book comes in the mail. I ordered a book on micro-controllers from Amazon recently, so that should be fun. 

I am just playing devil's advocate a bit. That's all. Actually, I am responding to criticism from my wife to some extent. I have been criticized by her (to be fair, she is not the only one) for building cars that she can not drive. I guess I am trying to live down my reputation for building cars with which the driver must be intimately familiar if he wishes to get home. So far, I have received lots of compliments from her and several other people who have seen a couple of the cars that I've built lately. I guess I am making progress. Those cars were built for someone else too, so that makes a difference.


----------



## xrotaryguy (Jul 26, 2007)

Mr. Sharkey said:


> In order for a controller to limit current, it must first know how much current there is. This is accomplished by use of a shunt, which generates a voltage that's proportional to the amount of current in the circuit. The shunt voltage is compared to a calibrated reference voltage by a differential amplifier, and when the shunt voltage exceeds a predefined threshold, the controller stops widening the PWM to the output semiconductors, thereby clamping the current at a maximum level.
> 
> That circuit is all built into the PWM controller chip I mentioned elsewhere, but it can be built out of discrete components as well.


Does this mean that pulse width modulation regulates both voltage And current?


----------



## Dan Frederiksen (Jul 26, 2007)

PWM is only a switch. the intelligence behind that switching can regulate both voltage and current.
current has momentum so you can think of current like a heavy motor spinning up when you switch it on. the longer it's on the higher the current 'spins up'. if you then only switch it on some of the time you can hold it at a certain level. same for the voltage really except that doesn't have momentum, it's more a simple case of average. 
but you can't control them independently as you may have guessed. that comes from a interplay with the motor. for instance if a motor is stalled the current will occur with very little voltage so even at very little PWM duty a very high current can occur. that's why the start is the most critical in terms of current limitation. at higher rpm the motor needs much more voltage (higher PWM duty) to maintain the same level of current. the motor is more hungry when doing more work.

a shunt is not the only way to measure current though. like a clamp meter it can be done magnetically. somewhat more elegant than a shunt. albeit sensitive to magnetic influence


----------



## xrotaryguy (Jul 26, 2007)

Excellent. Thanks again for the quick reply. This is what I had begun to suspect I guess. I am really starting from square one here, but my learning curve is steep. Well, as steep as it can be while I am still in school. 

I have another question too. Mr Sharkey mentioned an LM3524 microcontroller. I looked at National Semiconductors' data sheet on that controller, and it states that the controller's duty cycle is only 44% per output.


http://cache.national.com/ds/LM/LM2524D.pdf said:


> duty cycle per
> output has been improved to 44% compared to 35% max.
> duty cycle in other 3524s.


I also noticed another site that makes a similar claim.



http://www.4qdtec.com/pwm-01.html#intro said:


> The circuit uses a 3524, a 'regulating pulse width modulator' so a brief description of the IC seems to be in order. The chip is aimed at power supplies and it has dual alternating outputs (pins 11 & 14) each of which can be on from 0% to 45% of the cycle time. But these outputs can be connected together as we have done here. Connected thus the output is a regular pwm output (as described at the top of this page) with a fixed frequency and an on time variable from 0% to 90%. Which, incidentally, is one of the chip's main shortcomings - a 90% on time means that you can only get 90% of full speed, not 100%. This is the main reason 4QD stopped using it.


The claim made earlier was that this controller had a better duty cycle than a 555 timer. Is there some way to make the controller actaully have a 100% duty cycle?

Also, TheSGC said that he was going to use an Atmega8 controller. I looked at a few of their 8 bit controllers, and I can't seem to find a duty cycle rating for any of them. Does anyone know what the duty cycle on these chips might be?

Sorry for the ask 20 questions. I'm learning, I promise!


----------



## Dan Frederiksen (Jul 26, 2007)

I sincerely hope the atmega has 100% duty cycle. but I just assumed since it's digital and anything else would be idiotic. if not I'll build a cruise missile and destroy their company : ) that would just be too stupid


----------



## TheSGC (Nov 15, 2007)

Dan Frederiksen said:


> I sincerely hope the atmega has 100% duty cycle. but I just assumed since it's digital and anything else would be idiotic. if not I'll build a cruise missile and destroy their company : ) that would just be too stupid


I am still trying to figure that out too before I get one. It would be pretty stupid not to have 0 to 100% duty cycle, but its not unheard of. Right now I have built a simple 555 Timer system that does 0 to 100% duty cycle, but there is no current limiting or programmability. It works just fine tho, and allows me to build the motor drive part of the controller and test it.

I have also been looking at microchip.com and they have some nice chips that can be ordered as free samples, providing that you don't use a generic e-mail address to get them.


----------



## xrotaryguy (Jul 26, 2007)

Dan Frederiksen said:


> I sincerely hope the atmega has 100% duty cycle. but I just assumed since it's digital and anything else would be idiotic. if not I'll build a cruise missile and destroy their company : ) that would just be too stupid


You cold use the Atemega in the guidance system. 

Maybe we'll have to call the manufacturer or a sales rep on Monday. The chip DOES have 3 pwm channels, so if each of them only has 50% duty cycle, then two of the channels could be used to achieve 100% duty cycle. Or, if each channel has only 44/45% like the newer 3524 chips, then each channel could be programmed to run between 0% & 33.3% duty cycle. That would get you 99.9%. Unless you're drag racing, I doubt that you'll miss the last one tenth of on percent.

The downside with this sort of wiring is that the chip no longer has any pwm capabilities for anything else. Lame.


----------



## Dan Frederiksen (Jul 26, 2007)

I trust it has full range pwm. can operate as either 8bit or 16bit precision


----------



## Greenflight (Sep 13, 2007)

For the record (and risking sounding like a microchip salesman) many PICs have full 0-100 PWM that is really easy to use... It should be possible to have an entire driver on one chip (minus power supply). Hopefully pretty soon after I reinstall PicBasic Pro I'll be able to get one going...


----------



## xrotaryguy (Jul 26, 2007)

Aah, thank you Mr chip salesman.  So, does that mean that the IXDD414PI driver in Dan's circuit could be eliminated with the use of a different chip? If so, do you know which chips might be capable of this? Again, sorry if this is a bit of a newb question. I get the impression that I have the least experience with this sort of thing of anyone in this discussion.

That said, what is the purpose of the driver in Dan's circuit? it looks like it takes a 5v input and outputs a 15v signal to the IGBT. Is that all it does? Does it require additional programming? Thanks.


----------



## Dan Frederiksen (Jul 26, 2007)

that's what it does. the signal is only a signal where as the output has some power as well as higher voltage


----------



## Greenflight (Sep 13, 2007)

Dan's going to have to explain a little more about the purpose of that driver... I'm kind of in the same boat as you as far as that goes. Looking at the datasheet, it looks like it's basically just an amplifier (kinda like a preamp I guess).

I never new such a chip existed- I was planning on using a series of MOSFETs to drive the IGBT.

What the PIC would eliminate (sounds like the Atmega would as well) is a 555 timer or similar chip (I think sharkey mentioned the LM2524?) for creating the actual PWM. I've been able to run a small motor at varying speeds through a single MOSFET directly with the PWM from the PIC. The chip that I'm playing with is the PIC16F628A.

What I'm having problems with is the sensing circuit. For some reason my compiler doesn't like ADCIN commands. If I can find the CD I'll reinstall it and try again... 

edit: thanks Dan!


----------



## Greenflight (Sep 13, 2007)

Here's a link to a guy that built a golf cart controller with an Atmega. Looks like his circuit is a lot like Dan's. He has the C code and everything on there. Might be useful.

http://www.zeva.com.au/speedy/


----------



## TheSGC (Nov 15, 2007)

I am also still trying to figure out the current limiting. I have place an order for some samples of PIC controllers, with full PWM controller and 10 A/D converters. My 555 timer based system works, but current limiting is way too much work on it, and using a PIC controller is so much more usable. That, and I can probably get help from some of my professors to make this thing as fool proof as possible. I also have a 1200Volts 300 AMP IGBT on the way, which will be used instead of MOSFETS for now. I am going to have the current limited to 250 AMPS max as anymore will burn out my motor!


----------



## xrotaryguy (Jul 26, 2007)

Greenflight said:


> Here's a link to a guy that built a golf cart controller with an Atmega. Looks like his circuit is a lot like Dan's. He has the C code and everything on there. Might be useful.
> 
> http://www.zeva.com.au/speedy/


Cool, it's a 3 wheeled cart. If he sands off the vin number he might be able to register it as a home made motorcycle and ride it on the freeway. 

Anyway, thanks for the link. I actually ran across that guy's site a while back but didn't know enough to appreciate it at the time. Having a little bit of code to start with is super helpful too.



greenflight said:


> Dan's going to have to explain a little more about the purpose of that driver... I'm kind of in the same boat as you as far as that goes. Looking at the datasheet, it looks like it's basically just an amplifier (kinda like a preamp I guess).
> 
> I never knew such a chip existed- I was planning on using a series of MOSFETs to drive the IGBT.


I guess I understand the purpose of the driver now. Understanding the driver helps to understand why the power supply includes a 15v output too because the driver's collector/emitter voltage needs to be about 15v. Likewise, it looks like the IGBT needs 15v. I guess you (greenflight) already knew that though since you were planning on using FETs in the place of a driver. I can't imagine why using FETs wouldn't work. Then again, I barely have any idea what I'm talking about 



greenflight said:


> What the PIC would eliminate (sounds like the Atmega would as well) is a 555 timer or similar chip


Ok I see, I thought that you were saying that some PICs could do the job of a driver. I haven't done as much research in this field, but I have not yet come across a PIC that can modulate a 15v signal. That would be nice though. 



thesgc said:


> I have place an order for some samples of PIC controllers, with full PWM controller and 10 A/D converters.


Arent A/D converters generally integrated into a PIC?


----------



## Dan Frederiksen (Jul 26, 2007)

you can replace the driver with other components but why not a single simple part..
the gate of a FET or IGBT is like a capacitor, charge it up to open, discharge to close. you need both in the driver


----------



## TheSGC (Nov 15, 2007)

> Arent A/D converters generally integrated into a PIC?


I was just saying that the PIC has the full dedicated PWM and 10 A/D conveters in it.


----------



## TheSGC (Nov 15, 2007)

I have decided that my controller is going to be two seperate parts. One part will be the PWM circuit with the microcontroller and LCD drivers. The other will be the actual power. I am doing this so it can be easily upgrade in the future, or if I build these for people, it has the ability to be upgraded in a second. So instead of buying a whole new $2K controller, it would be like a $250 upgrade or something like that. Then I could literally create custom controllers per order on what voltage and AMPs are desired.

I have enough MOSFETs to build an outrageous 660 AMP continuous controller, but only at 84 volts max. That can easily be upgraded with an IGBT system, or higher end MOSFETS. Assuming my parts come in next week, I hope to have this thing all set to go by March, with the exception of the LCD display.


----------



## xrotaryguy (Jul 26, 2007)

Sweet. Finally an affordable controller that can handle high voltage... eventually... maybe  I like your plan of building a modular system to cut down on construction costs. I was thinking that this sort of setup would work out well for an affordable controller as well. Another benefit of having the MOSFETS or the IGBT in its own box is that it is less likely to interfere with the circuitry of the rest of the controller.

Another option for an affordable controller could be something like the MEGASQUIRT where a person purchases all of bits and pieces and then solders them together himself. This could have the potential of propagating a host of independent controller builders that would then sell completed controllers for a small profit to themselves. That could save the controller designer/"kit supplier" from the worry of the types of production issues that may arise with an inexpensive controller (eg. high demand despite lengthy lead time). This could also release the kit supplier from a certain amount of liability.


----------



## TheSGC (Nov 15, 2007)

The IGBT that I have on the way is rated up to 1200 Volts and 300 AMPs. And I could have gotten a 600 AMP version, and they have higher AMPS available, but my motor will cook at 300 amps anyways. So this thing could technically could take anything you could possible through at it on a DC format, and the only thing that would need adjustment would be the shunt used for current sensing and programming the controller for the different votlages, provided the IGBT is rated to your liking.


----------



## xrotaryguy (Jul 26, 2007)

hahaha, it sounds like you're already trying to make your first sale.


----------



## TheSGC (Nov 15, 2007)

xrotaryguy said:


> hahaha, it sounds like you're already trying to make your first sale.


Yeah is does, doesn't it.

Anyways, I am also looking around for a decent inexpensive serial LCD for status goodies and what not. 

Does anyone know what to use for a decent casing for this thing? Plastic Radio Shack project boxes probably won't cut it, and I can't seem to find any of those cool cases that other controllers use.


----------



## TexomaEV (Jul 26, 2007)

TheSGC said:


> Does anyone know what to use for a decent casing for this thing? Plastic Radio Shack project boxes probably won't cut it, and I can't seem to find any of those cool cases that other controllers use.


Check out, and or search for Extruded Aluminum Cases. Here's the first one I came up with:

www.enclosuresandcases.com/tspecpage.html

http://coscoal.manufacturer.globals...uminum-extrusion/1003471291/Aluminum-Case.htm


----------



## Greenflight (Sep 13, 2007)

A good LCD is one controlled by the Hitachi 44780. This is the one I got: http://cgi.ebay.com/2x16-character-...ZWD1VQQ_trksidZp1638.m118.l1247QQcmdZViewItem

It'll take up a few I/O pins, but it's really easy to interface to a PIC. Plus you can get them in 20 x 4 displays too.


----------



## xrotaryguy (Jul 26, 2007)

Wow, you guys are really on it with this stuff. I wish I had more time to pursue this right now.


----------



## TheSGC (Nov 15, 2007)

I just got my PB5 throttle and started some serious bench testing. One thing that I did not realize is that they throttles only have 2 wires, and the controller I built needs 3 so I have to add the other wire.

But here is the kicker. When doing my testing I realized that the controllers out there never go to 0 to 100% duty cycle. The PB throttle do not go all the way to 5K ohms, but 4.8K ohms all the way to the floor, and that ends up being about 95% max, if not less.

So the only thing a microcontroller has over a basic 555 timer system is the programmability. I am almost done with my 555 controller, complete with current limiting, but it runs at 2KHz, so its audible. (I am working on something higher, but sadly to say the high end Curtis controllers seem to also run at this frequency, and the higher frequencies don't seem to really work properly when driving the motor.)


----------



## Dan Frederiksen (Jul 26, 2007)

'only' programmable 
I think you will find that it is quite the advantage. you can modify frequencies, you can observe current, you can even do spread spectrum switching meaning a constantly changing frequency which is a clever way to avoid the ringing at low frequency.
it also means you are not bothered by 4.8kOhm limits


----------



## Greenflight (Sep 13, 2007)

Yup, I agree with Dan. I'm planning on including a throttle calibration sequence that will automatically find and save throttle endpoints. Whether or not I ever get it done, remains to be seen!


----------



## TheSGC (Nov 15, 2007)

Throttle calibration would be nice. I definately want it to be microprocessor controlled, but I also think it would be kind of cool to have a working controller that is can built anywhere there is a Radio Shack. My entire budget for this controller was $150, in case it did't work, or I gave up I wouldn't have blown a load of cash on it. Well, I have used $140, and $107 of that was actually the PB5 and Shunt, which were not part of that budgeted section of the project, so I did quite well using only $33 for parts.

Now I just need to get what I have into some form of enclosure so I can have it tested by a fellow EV'er! And a nice instruction manual too.


----------



## Dennis (Feb 25, 2008)

Why not add the ability to make the motor constant speed under varying load conditions? Like say the motor turns 2000 RPM under light to severe loads. Thats what is done in industry, its called constant torque. The torque curve is completely horizontal up to some RPM limit then it falls off as 1/X in quadrant one of a Cartesian graph. It can be implemented by a tachometer sensor.


----------



## Dan Frederiksen (Jul 26, 2007)

that would be a kind of cruise control. not basically needed but could be done. and it would probably be called constant speed. rather than constant torque which it isn't. a tachometer is useful for insuring the motor speed doesn't exceed its max rpm anyway


----------



## Dennis (Feb 25, 2008)

Read this first:


http://www.motorsanddrives.com/cowern/motorterms23.html


It is not for cruise control but for speed regulation. Like say I do not wish to press the throttle down any harder when climbing a hill, but instead have the controller maintain the RPM set point that the throttle is at. Its used a lot in industrial control of large DC motors.


----------



## Greenflight (Sep 13, 2007)

Yup, that's the idea of cruise control. Should be pretty easy to implement with an RPM sensor.


----------



## Dennis (Feb 25, 2008)

This is not exactly like it in that it's not a button someone presses and let the car hold that speed, BUT it is when the operator depresses the accel pedal that in turn produces a square wave duty cycle in proportion of the potentiometer position, BUT a tachometer sensor is used to hold the speed of the motor at the correct RPM for that particular position of the potentiometer wiper arm by having the controller COMPARING the set point which is throttle position to ACTUAL speed of the motor sent by the tach, then compensates by increasing the square wave duty cycle (average voltage increase) such that the armature will maintain proper speed so that the operator does not have to press the pedal so far down. HOWEVER, it ONLY compensates for under speed conditions. If the armature spins faster, then it should not compensate, only when the armature speed FALLS below set point should it compensate. I suppose you could make it a button to press....

This would allow for example 30 MPH up steep hills, hauling heavy loads and such. The down side though is you need lots of voltage to do this because speed is compensated by increasing armature volts to keep the RPM set to the throttle position that the operator has his/her foot pressed to.

It would make a nice pulling truck. Could you imagine not ever losing speed from hauling heavy loads LOL!!


----------



## xrotaryguy (Jul 26, 2007)

Aah, so something like 1/5th throttle = 1000 rpm, 3/5ths throttle =3000 rpm and 5/5ths throttle (read full throttle) =5000rpm.


----------



## Greenflight (Sep 13, 2007)

Yeah, I get it now. That could be kinda cool. I'm just trying to imagine what it would be like driving something like that...


----------



## Dan Frederiksen (Jul 26, 2007)

it could be done but it would feel odd as it would be different from what we are used to. it would accelerate as hard as it could until the rpm was reached and then suddenly stop there. you can try it in a car and go for a specific speed at max accel.
and if you slowly depress the pedal it would switch on and off aggresively. probably wouldn't be natural but some tweeks could be done to make it more laid back. not sure what it would gain though


----------



## Bugzuki (Jan 15, 2008)

I think that cars work better through the variation of power from the pedal instead of variation of speed. It is too hard to hold your foot in a single location enough to stay at an exact speed. I say leave the pedal a way of modifying the power and add a cruise control function later if you want.

We did some testing at WWU and found that power modulation is the most natural feeling - in a car (to me while testing). In equipment or machinery speed modulation would be very appropriate, because you do not necessarily feel the machine slow down. So, you need to have it adjust itself. 

Just my 2 cents.


----------



## Dennis (Feb 25, 2008)

> it could be done but it would feel odd as it would be different from what we are used to. it would accelerate as hard as it could until the rpm was reached and then suddenly stop there. you can try it in a car and go for a specific speed at max accel.
> and if you slowly depress the pedal it would switch on and off aggresively. probably wouldn't be natural but some tweeks could be done to make it more laid back. not sure what it would gain though


This can be solved by introducing some form of derivative function such that as the operator pressed the pedal slowly then the rate of change is slow and therefore the controller would gradually ramp the motor RPM up to that set point. Likewise, if the operator were to press the accelerator instantly then that would be a fast rate of change and the controller would quickly ramp up the motor speed to match the set point. I would also advise including some integration function as it's not easy for us humans to hold the accel pedal at some defined point. Therefore the controller can use the integration function to calculate an AVERAGE set point that the throttle is at to account for small variations.

What you have is Proportional+Integral+Derivative control. PID is used a lot in industry and ultra high end expensive motor controllers as well.


----------



## Bugzuki (Jan 15, 2008)

They did not name this thread "Homemade ultra high end expensive controller". I think what you are suggesting could be neat, but would take a lot of R&D and it would be musch easier to just vary the power with the pedal and then put in a speed control (cruise control) later after the system is working.


----------



## Dennis (Feb 25, 2008)

> They did not name this thread "Homemade ultra high end expensive controller". I think what you are suggesting could be neat, but would take a lot of R&D and it would be musch easier to just vary the power with the pedal and then put in a speed control (cruise control) later after the system is working.


R&D is not required as motor controllers for industry already have those functions and there are also some traction controllers such as Curtis controllers for separately excited motors that support PID control.

It's real easy to build an integrator or a differentiator using an OP amp and few resistors with capacitors. As far as doing it digital, I am sure there are math libraries for the available programming language of the micro controllers that have those math functions.


----------



## theboy16 (Feb 28, 2008)

hey guys, i'm in the early stages of designing a controller from scratch. i've got alot know-how when it comes to electrical and mechanical, but my logic/microchip stuff is kinda rusty

from what i've read, a PWM controller can be built with "relative" ease, and another unit could be built and set at a constant setting (14.5volts), making a high current dc-dc controller.

i'm looking for resources on microchip basics, so far wikipedia hasn't helped out a whole lot.

can anyone point me in the right direction so i can start doing some reading on these chips, what they do and how they work?

again, like i said, if its bigger than the palm of my hand, i have no problem with it; but these small electronics are kind of a grey area for me

thanks!


----------



## aeroscott (Jan 5, 2008)

im doing the same thing.on evdl i(about Jan.2,08) found a link to circuitceller.com/microchip2007/winners/mt2291.html this is 100 hp 3 phase motor controller.it can also be a dc controller with some mods. link from that to (microchip.com/motor)app notes ,web casts,etc.it will take 100's of hours but microchip all the info you can absorb.school on the net!its a huge site.


----------



## theboy16 (Feb 28, 2008)

thanks for the tip!


----------



## n8thegr8 (Feb 11, 2008)

I stumbled on this thread, and I clicked about the arduino for some reason. I'm building one to program for something along the lines of an open-source scanguage to display instantaneous mileage/speed/etc. for my ICE car. For anyone who's never heard of it, the arduino is a sort of open source hardware platform based off of the atmega8 microcontroller, and it features and easy to use IDE for programming it. It also features libraries for TONS of applications such as LCD output, motor control, etc (I even saw code that uses all the output pins for multiple PWM). Whenever I get around to starting my conversion, I'm going to look into using it as a brain for a motor controller, being that it only costs about $16 to build, or $19 for a kit. It might be worth looking into, if only as an intro to microcontrollers (http://www.arduino.cc for more info). Hope this helps!


----------



## ecvs (Mar 4, 2008)

I have just started a group in yahoo called evcs, which will be an open source project to design pulse width modulated vehicle controllers with IGBT drives and mosfets etc. If any of you fellows have Electrical and Electronic knowledge to help out in the designs, please feel free to join up.
Tom


----------



## Dan Frederiksen (Jul 26, 2007)

ecvs, I'd say do it here or an irc channel. I wont join yahoo. as I recall it was clumsy. if you try IRC and I seriously recommend you do, I'd say do it on freenode. a live forum is infinitely better. and it can be logged for web review


----------



## ecvs (Mar 4, 2008)

Hi Dan,

I will use this forum for communication purposes and provide links to here from the yahoo group. Yahoo provides a files section to put schematics and various other information up so anyone can get at and view as desired without having to look through a pile of postings. I don't think this forum provides that ? Or perhaps I'm wrong in assuming this. 
At any rate I like the idea of the forum here to be used for communication instead of posting on yahoo and creating a long list of posts.
I will add the link to here on the group shortly and add a message on the group to use this site for communication. 

Tom


----------



## theboy16 (Feb 28, 2008)

so, since we're making our own PWM controller, we could use any kind of potentiomenter we want for the input, and not just the standard 0-5kohm boxes.

why re-invent the wheel when we most vehicles now have a throttle by wire setup anyways? 

did i miss something? lemme know!


----------



## Bugzuki (Jan 15, 2008)

I tried joining a yahoo group once, but it was extremely hard to follow what was going on and was very unorganized. Sorry, but I will not join another Yahoo group. If you want to do something like that do it here. If you want I have a website that I could setup to serve the documents and stuff. It is www.hybridaction.com I have not gotten it where I want it, but I was trying to make a site to support the electric vehicle arena.

Let me know. This should be taken to a different thread or to PMs so that this thread does not get highjacked.


----------



## ecvs (Mar 4, 2008)

Thanks anyways but I'll keep the communication here and the files on the yahoo group. I don't see any confusion with the yahoo group... relatively easy to navigate. You simply join the group, and once your membership is processed by me, you can access the files, links, etc on the left navigation. I don't particularly like the posting method on yahoo but that is why I'll use this forum. Anyways... I have chosen the Pic18Fxx31 series microprocessor where you can find links to the data pages on it at the yahoo group. This processor is specifically designed for motor controllers for every type of motor and set up you can think of. This way no matter who wants to build a controller they have a good basis to start from.
Tom


----------



## ecvs (Mar 4, 2008)

I have also found an IGBT driver IC all inclusive that looks promising. 
Check out the link here if your interested in something that should work for most IGBT's http://cc.msnscache.com/cache.aspx?q=72917663878831&mkt=en-CA&lang=en-CA&w=98868780&FORM=CVRE
Tom


----------



## theboy16 (Feb 28, 2008)

the article seems incomplete, there is reference to some figures, but i didn't see them. did i miss something?


----------



## ecvs (Mar 4, 2008)

Sorry about that. For some reason the link falls apart... that also happend to me tonight... but I found it as a PDF file ...here http://powerelectronics.com/mag/503PET21.pdf
I have also set it up as a link on the yahoo group and you are now approved as a member now


----------



## ecvs (Mar 4, 2008)

I have added the schematic diagram of the Universal IGBT controller drive in the files section on the yahoo group evcs. This circuit could easily be used with a simple pulse width modulator to make a basic high power drive system.
Please follow the link from my previous post to read up on the component values. There is a component parts list found there. I will add exact component values once I decide which IGBT I will use... most likely I'm going for a 1200Volt 800 Amp IGBT.
Tom


----------



## ecvs (Mar 4, 2008)

Mr. Sharkey said:


> Other important features? Like:
> 
> Current limiting
> RPM limiting
> ...


Please explain what Interlock ladder inputs are? 
Thanks
Tom


----------



## Greenflight (Sep 13, 2007)

So... After weeks of trying to figure out why I couldn't get my compiler to compile ADC programs (and bragging about the PICs ADC ability), I officially qualify as an idiot... It turns out the PIC I'm using (16F828A) doesn't support ADC.  

TLC549 serial A/D converter ICs on the way to my house as we speak...


----------



## TheSGC (Nov 15, 2007)

Greenflight said:


> So... After weeks of trying to figure out why I couldn't get my compiler to compile ADC programs (and bragging about the PICs ADC ability), I officially qualify as an idiot... It turns out the PIC I'm using (16F828A) doesn't support ADC.
> 
> TLC549 serial A/D converter ICs on the way to my house as we speak...


My PIC 18 just came in today and now I have to figure out how to interface it with my computer...

Anyways, my nice test controller that is 84 Volts 250 AMPS continuous that consists of mostly Radio Shack parts is nearing its completion. All I have to do now is finish putting it together in a case and get some pretty pictures!


----------



## Greenflight (Sep 13, 2007)

Yeah, I'm sure the 18F series has ADC... Oh well. What programmer are you using?

You know, I've been playing around a little with 555s, and I can't get one to work as a controller... Any chance you could post a schematic or diagram?


----------



## TheSGC (Nov 15, 2007)

It took sometime and trial an error to get a 555 controller working, but I will gladly post my schematics tomorrow. I have all my notes and sketches in a notebook and not in a complete understandable format, so I will make it into one and post it. I have even come up with a current limiter for it, but it requires a 50mv shunt. The only thing is that it requires a 3 wire pot, so the PB5/6 needs the extra wire to be soldered onto it. (I haven't found a way around that yet, but I am wokring on it) I designed it using a 5K potentiometer from Radio Shack and then had one of those "oh ****!!" moments when my PB5 came in and it was 2 wire, but luckily its the same pot and has the extra connector for the third wire right there.


----------



## theboy16 (Feb 28, 2008)

so... any word on what interlocking ladder inputs are? cuz i'm confused!


----------



## Mesuge (Mar 6, 2008)

n8thegr8 said:


> I stumbled on this thread, and I clicked about the arduino for some reason. I'm building one to program for something along the lines of an *open-source scanguage* to display instantaneous mileage/speed/etc. for my ICE car.


That sounds very interesting, can you elaborate a little bit more or start a separate thread? Thanks


----------



## Mesuge (Mar 6, 2008)

aeroscott said:


> im doing the same thing.on evdl i(about Jan.2,08) found a link to circuitceller.com/microchip2007/winners/mt2291.html this is 100 hp 3 phase motor controller.it can also be a dc controller with some mods. link from that to (microchip.com/motor)app notes ,web casts,etc.it will take 100's of hours but microchip all the info you can absorb.school on the net!its a huge site.


Plans for 100kW AC drive - diy style and no reaction so far*?* Am I on the right forum? EV anybody? huh
Perhaps it was just a typo in that original hyperlink (this works):
http://www.circuitcellar.com/microchip2007/winners/mt2291.html
http://www.microchip.com/motor


----------



## ecvs (Mar 4, 2008)

Mesuge said:


> Plans for 100kW AC drive - diy style and no reaction so far*?* Am I on the right forum? EV anybody? huh
> Perhaps it was just a typo in that original hyperlink (this works):
> http://www.circuitcellar.com/microchip2007/winners/mt2291.html
> http://www.microchip.com/motor


I have looked over this design and notice that the power drive section is not on the schematics provided. I have sent an email to the one fellow who has left his email to for contacting to see if I can get complete information package for it and have asked for permission to host it on the open source evcs (electric vehicle controller system) group on yahoo. 
Tom


----------



## Mesuge (Mar 6, 2008)

Tom, thanks for the info, I've been still reading the abstract at that point. So, homebrew 100kW AC drive -> too good to be true? I'm wondering how regen, EMI, possible add-on high voltage bidirectional charger and other important issues stemm from their design? The internet seems to be oddly silent on this topic and particular drive, strange hah. Here is that mentioned short comment on EVDL from Danny:

http://www.diyelectriccar.com/forums/showpost.php?p=18765&postcount=1
http://tech.groups.yahoo.com/group/ev/message/36054

update: Tom, are you sure?, have you read all the word (.doc) documentation, at one point they provide additional external hyperlink for schematics.. other than that the whole downloadable info pack ~47megs seems to be complete: manual, code, schematics, pictures.. 

--
Also the projected price < $2.5k in new parts and less ebay/surplus (add time assembly/solder job) 
seems reasonable in comparison to other ~100kW on the market, although one has to take into account
this one is still somewhat experimental..

Spec from user manual: 

"_..The rated continuous output current from the inverter is 200A (RMS). This allows up to approximately 96kW output when running from_
_a 230 to 480VDC voltage in a maximum 30°C (85F) ambient temperature environment. Thus, the system is capable of running a standard_
_3-Phase ACIM of up to 96kW which is generally enough to accelerate any common car up to highway speeds. The power module is _
_capable of driving other types of motors and electrical loads that do not exceed the maximum power limit and are predominantly inductive..._"
--

Again downloads here:
http://www.circuitcellar.com/microchip2007/winners/mt2291.html

some more theory:
http://www.microchip.com/motor

-


----------



## Greenflight (Sep 13, 2007)

Wow... That looks like a pretty sweet deal. So far (dial up) I haven't downloaded anything yet. What link did you follow to download the "info pack" that you're talking about?


----------



## Dan Frederiksen (Jul 26, 2007)

2500$ in parts is not good. done right I expect more like 200$ in parts. maybe less


----------



## Greenflight (Sep 13, 2007)

ecvs said:


> I have also found an IGBT driver IC all inclusive that looks promising.
> Check out the link here if your interested in something that should work for most IGBT's http://cc.msnscache.com/cache.aspx?q=72917663878831&mkt=en-CA&lang=en-CA&w=98868780&FORM=CVRE
> Tom


Do you know of a source for these chips? I checked some of the usuals (mouser, digi-key) and couldn't find them.


----------



## Mesuge (Mar 6, 2008)

As pointed out previously the suggested pricetag is upto $2.5k which is an estimate based on new parts and some equipment needed for the watercooling/sealants which can be used for several of these drives etc. Most likely it could be done for much less, check ebay/surplus shops for these IGBT/gates and so on. List of all parts/kits/vendors needed is enumerated in the manual:

by "infopack" I mean the second link on that site (~47megs):
http://www.circuitcellar.com/microchip2007/winners/entries/MT2291.zip

--
$200 for 100kW AC 3phase inverter hah? Well good luck.. 
Mind you many of the parts (development board related) in this project are needed for debugging, so a standalone drive version with preselected/matching specific induction e-motor would make it even cheaper. 

If you don't like the price, perhaps call da AC king Mr. Cocconi to give you similar discount on his $25k system (~150kW)..
--

In any case we need firstly some independent replication/verification of this project, preferably in any sort of driving EV mule..

From what I've read so far it seems to me that regen functionality will need some additional circuitry like brake chopper/resistor etc.. But it is implemented in software and general design of the drive. Regen is for sure in the first area of questions we should ask the authors about..


----------



## Mesuge (Mar 6, 2008)

Component part list/datasheet digested from manual (pricing for new):

_1a/ High Voltage Module - Components:_
--------------------------------------
- [BG2B-5015] Gate Driver Assembly (Powerex): 3x (~ $110)
http://www.pwrx.com/Result.aspx?q=BG2B-5015
http://www.pwrx.com/TechnicalDocument.aspx?id=800

- [CM400DY-12(N)F] Dual-IGBT Modules (Powerex) : 3x (~ $200N-260F)
http://www.pwrx.com/Result.aspx?q=CM400DY-12NF

- [AN_121KIT] Bus-bar Current Sensor (GMW Ass.): 2x (~ $30)
http://www.gmw.com/magnetic_sensors/sentron/csa/CSA-1_Acc.html#AN121


- [250x160mm Hydroblock ] Liquid Cooled IGBT Coldplate (D6 Industries): 1x (~ $180)
http://www.d6industries.com/heatsinks/index.htm

'---- optional/or other form of cooling/supporting mechanics/frame


_1b/ High Voltage Module - Hardware:_ 
------------------------------------
- lots of smallish bits and pieces see manual, that copper bus bar perhaps most expensive item..


_2/ Control Board Components:_
------------------------------
- [dsPIC30F6010A] MCU (Microchip): 1x (~ $11)
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1335&dDocName=en025842

- [dsPICDEM 1.1 General Purpose Development Board] Dev. board for dsPIC30F6010A (Microchip): 1x (~ $299-399)
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en023537
(Or alternatively diy version of this dev board as depicted in the manual, right?)
The schematics for all these *boards are included in the documentation pack with date 10/15/07 -
no revision mentioned though.. 
According to one submanual, it was also supposedly placed for download here in latest 1.4 revision but can't find it:
(most likely it's the same version) www.elex.camosun.bc.ca

- CANBUS Doughter *Board/USB 

----
So, there are some costs involved (~ $1.5k as new) but it could be chopped down significantly either as samples, ebay/surplus/ or uni/work lab equipment etc.. Add a few bucks for quality DC & 3phase connectors. The price of trusty industrial induction e-motor is not included as these can be sourced at every local scrap yard just for the price of the metal. And new ones are relatively cheap anyway..


----------



## Greenflight (Sep 13, 2007)

I like it... Maybe after I get a little more experience I'll try to build one. It looks like after you build the driver the power stages could be just about anything you want. Very cool.


----------



## ecvs (Mar 4, 2008)

Mesuge said:


> Tom, thanks for the info, I've been still reading the abstract at that point. So, homebrew 100kW AC drive -> too good to be true? I'm wondering how regen, EMI, possible add-on high voltage bidirectional charger and other important issues stemm from their design? The internet seems to be oddly silent on this topic and particular drive, strange hah. Here is that mentioned short comment on EVDL from Danny:
> 
> http://www.diyelectriccar.com/forums/showpost.php?p=18765&postcount=1
> http://tech.groups.yahoo.com/group/ev/message/36054
> ...


I have downloaded most of the files for this project from circuitcellar. It is a good design as far as I can see.
I did finally find the power drive section upon digging deep. I haven't found any references to more information available somewhere else. Could you send me the links?
This project has everything and more for any AC motor for industrial use. I like the fact that the system I'm designing is using the same manufacturer powerrex for the components. In fact I chose the VLA500-01 IGBT driver. I have pricing on the VLA500-01( 57 dollars in qty, somewhat more for small orders) from Richardson Electronics and hopefully have samples happening. I have asked the owner of the project if I may host it and it's associated files on the evcs.
The first system I'm designing is essentially a stripped down version of this one for the power drive section.
Because for the first system, I'm only doing a brushed DC motor drive system, which only requires one drive channel. For AC or brushless you need at least 3.
I'm still going to use the 18F series pic because its cheap and will do everything the pic they chose will.
The only thing I don't like about their system in fact is their choice for the developement board. Apparently the software to use it is 700 bucks or there abouts.
Tom


----------



## ecvs (Mar 4, 2008)

Dan Frederiksen said:


> 2500$ in parts is not good. done right I expect more like 200$ in parts. maybe less


Hi Dan,
I have to agree with you on that one. A basic DC brushed version should be much cheaper than 2500, but remember their system is a system rated up to 300 hp motors, and it's AC. They need more drive channels and electronics to control it. And they bought the farm with the development board they used and its associated software. It's a one time fee (probably good if you were into making these systems for multiple uses)
I'm going to have a decent system together in a while on the evcs yahoo group for in and around 400 bucks is where I'm hoping to keep it at. But time will tell.
Tom


----------



## Dan Frederiksen (Jul 26, 2007)

mark my words Mesuge. take a look at pricing for IGBTs in the TO247 or TO220 form factor. try digikey.com. using the large modules you get robbed. that's why curtis, zilla, kelly etc controllers don't use them. 400V 250A is not all that hard to do even in 3-phase.

I am quite familiar with Alan Cocconi and while he has built some good systems they are grossly lacking in price optimization. either he doesn't care or he doesn't understand it can be done.

somewhat disappointing that in all the world I seem to be the most likely person to demonstrate how cheaply it can be done. and I am the great procrastinator.


----------



## Mesuge (Mar 6, 2008)

ecvs said:


> The only thing I don't like about their system in fact is their choice for the developement board.
> Apparently the software to use it is *700 bucks* or there abouts.
> Tom


 
Tom> I gather you are talking about the expensive LabView suite for PC, right? Since the authors of this AC drive design have incorporated CANbus protocol to their control boards and the source code is available, I think it won't be that hard to hook it up with some opensource SCADA/HMI/process control software out there with similar basic functions as LabView.. From what I understand so far, in this drive design they are moving only that PID function related data stream (torque, flux, speed, plus IGBT failure signal, overheat etc.) on the CANbus which is not much. Most of the driving code is done at "black box" assembly prog. lang. level of the microchip, which is not meant to be accessible from basic user interface higher up (CANbus/LabView/PC)..

Just google it there are some viable opensource alternatives or much cheaper commercial/shareware apps. to LabView with CANbus/Modbus/Profibus protocol connectivity in them.. Also, there might be some evaluation licences for LabView, so you could test the system/control boards and tweak your induction motor of choice according to that supplied manual for this AC drive design and later move on another software for permanent operation..

Another great advantage of using industry grade SCADA system are cheap PLC I/O modules (upto 100s I/Os), which can be used to monitor every battery, control relays, read analog/digital odometer and any sensory data inputs of your EV for that matter etc. And all of this information is packed into single database, which is great for testing/debugging and obviously the major operational parameters of interest could be recalculated into human form and displayed on carputer's 7-10" lcd or PDA. Perhaps most of this functionality could be also achieved by developing your own specific hw/sw from scratch but in the end you will save just a few % (if any) of the budget and spend giant amounts of time on it, hence the modularity and replicability of such an endevour also suffers.. And if there is any enemy/disadvantage to the overall diy approach it's often in the modularity & replicability domain, which scares many people off..

Example of PLC in an EV: 
http://aztext.com/images/PLC_ZCC.gif
http://aztext.com/ZCC_photo_montage.cfm
(apart from the ~20 stock, there are no additional I/O expansions slots installed in this particular case, see these 4blank slots to the right, but could be filled by various I/O & relay/comm. modules, check the manufs. web for options)


Dan> Well, I'm not saying it can't be done on super tight budget or that you personally are not up to the task, I'm sorry if you take it like that, perhaps just petty scepticism on my part, I'm looking forward to documentation of your project!


----------



## TheSGC (Nov 15, 2007)

That AC controller does look rather interesting. And I still haven't been able to write up those schematics due to the fact that I have been dealing with flooded basements for the past two days. I also discovered that soldering copper wires to alumimun bars is a PAIN!! I have to get some copper plates and then bolt them down to my aluminum connectors and then solder my wires to them.


----------



## Dennis (Feb 25, 2008)

I would also like to add that PLC's are easy to program and MUCH MORE POWERFUL in raw processing power versus a pic micro controller. I mean even a 5 year old could program a PLC, its just ladder logic. I have RSlogix to program Allen Bradly PLC's..


----------



## Evan (Feb 20, 2008)

All of the PLC systems I have seen don't use regen on the motor though. They ether use DC injection or dump the extra power into a resistor. Does this thing have regen?


----------



## aeroscott (Jan 5, 2008)

Tom, we mite need a extra channel for the 3 phase model . I found a wound rotor motor ( well generator).Its a miller bobcat ,about 160 lbs,16 in. long,9.75 in. dia, 1.5 in. dia shaft. So for high starting torque the field is energized then as rpm's come up it is deenergized and becomes induction . i'll post this on welder as motor in technical discussion. OH, thanks to all for input on motor controller. John Stubbe


----------



## ecvs (Mar 4, 2008)

Ok update on the controller for the open source group on yahoo EVCS.
I have free samples comming of the VLA502-01's . Apparently they are available from Richardson Electronics. Also the IGBT's that I want to use (using two or possibly 3 in parallel) are relatively cheap... sales guy said about 40 bucks @. These are 1200 volts 400 amps, two will be plenty but if the need arises 3 can be done with very few extra components. 
Once I get all the components together for the power drive section I will build it and take pics, drawings etc. and post them on yahoo.
Please be patient. 
Essentially anyone will be able to build this section and add the rest of the system as it gets developed. We should be able to play around with a motor and a basic PWM just to see that it works. I will look into the possibility of using a PLC. What sort of cost are we looking at for a PLC? 
I have to find myself a decent brushed or PM motor for the single channel first. I may just bite the bullet and buy a new one. 
Tom


----------



## ngrimm (Oct 19, 2007)

Wow, you're moving right along on this. Is amps rating on the IGBT's you are considering measured as a pulsed rate or continuous? I noticed there is a big difference in the two ratings of the Mosfets I have been looking at in that the pulsed rating is much higher. Norm


----------



## MrCrabs (Mar 7, 2008)

Dennis said:


> I would also like to add that PLC's are easy to program and MUCH MORE POWERFUL in raw processing power versus a pic micro controller. I mean even a 5 year old could program a PLC, its just ladder logic. I have RSlogix to program Allen Bradly PLC's..


Yeah, but does your average DIYer have RSLogix, or Nxt, or Concept?
To program a pic all you need is a serial cable, to program a PLC you need some very pricey software.

Is there any more info out there about people using a PLC in their EV? I would love to design my own control system with the full power of a PLC, but it just seems like overkill.


----------



## Dennis (Feb 25, 2008)

> I would love to design my own control system with the full power of a PLC, but it just seems like overkill.


Then a pico controller which is a nano-PLC will be adequate for the job.


http://www.ab.com/programmablecontrol/plc/pico/controller.html

Here are many models to choose from as well:

http://www.ab.com/en/epub/catalogs/12762/2181376/2416247/1239730/3676481/tab5.html

The models that allow expansion of I/0 and use 12 DC power with display are this one:

1760-L18DWD-EX ( I personally think this is the perfect one)

others have some features missing:

w/o expansion option, but all other features:

1760-L12DWD

w/o display option, but all other features:

1760-L18DWD-EXND


If 12 volts is not your cup of tea then they also have 24 volt powered ones just below the 12 volt powered ones on that list.


The programming software is free for download here:

http://www.ab.com/programmablecontrol/plc/pico/picosoft.html

To buy the PLC's: http://shop.rockwellautomation.com/RA/index.jsp?scrnCurrentStore=RA


----------



## ngrimm (Oct 19, 2007)

I'm not sure what it would change in the design but I think it would be good if you could easily separate the controller section from the output stage. Then you could upgrade the power and voltage later as the parts prices come down. Norm


----------



## aeroscott (Jan 5, 2008)

would the plc seam like overkill with a 2 or 4 motor set up. thinking of ac motors plugged into standard independent suspension hubs or 2 motors on 2 differentials (4 wheel drive).ps Norm, the power module is remote from the cpu.


----------



## Dennis (Feb 25, 2008)

> I'm not sure what it would change in the design but I think it would be good if you could easily separate the controller section from the output stage. Then you could upgrade the power and voltage later as the parts prices come down. Norm


PLCs are modular in design, meaning there are actually modules that plug into a back plane slot of the PLC rack. You can buy any I/O module that suites your needs and simply plug it in to the back plane slots and the PLC will know its there with no need for updating software code. It has all the addresses of the ports already hard programmed in. Its not like a Windows computer in where you have to have a driver for unknown hardware. 

There are I/O analog modules that can put out 0-10 volts and some motor controllers support such an input as throttle. My AXE7234 can be set to take inductive, 0-10 volts, 0-5K, or 0-1K as throttle types.

The beauty of this is you can program in a limit on RPM's into the PLC for example and have an RPM sensor hooked up to an I/0 module and if the RPM's exceed the limit, then the PLC can immediately shutdown the motor controller since it has control over throttle input. On yeah the display will tell you what fault has occurred if you programmed the PLC to alert by display output.

Not only that but since PLCs are so fast they can multi task. So you can have the PLC monitor all sorts of sensors and have it shut down the problem area and/or alert you of the problem.



> would the plc seam like overkill with a 2 or 4 motor set up. thinking of ac motors plugged into standard independent suspension hubs or 2 motors on 2 differentials (4 wheel drive).ps Norm, the power module is remote from the cpu.


The PLC models I linked to from Allen Bradley are the perfect choice for this setup. Supporting up to 32 I/O is more than adequate for the job. It is a nano PLC which is the smallest you can go. The big daddy's are PLC's like the SLC 500!!! That's what you would call over kill!


----------



## ecvs (Mar 4, 2008)

ngrimm said:


> I'm not sure what it would change in the design but I think it would be good if you could easily separate the controller section from the output stage. Then you could upgrade the power and voltage later as the parts prices come down. Norm


Hi ngrimm,
This is exactly what I am intending to do on the open source evcs group in yahoo. I am building the drive section as a module and then I am going to do a very basic PWM to test it first. Then I will build a pic controller system again modular. 
Tom


----------



## Dennis (Feb 25, 2008)

There is one thing that is bothers me somewhat is that do you plan to send the PWM signal from the controller section by means of wires to the power section? That would severely distort the PWM modulation signal form the inductance of the wire. Its best to have a voltage level increase or decrease from controller section as a signal for the the power section to determine the duty cycle of the PWM by looking at the voltage level. I am sure you can program a pic as a ramp oscillator on the power section and then have it take voltage level input and from those two inputs it should put out a pulse width modulation duty cycle in proportion to the DC level from the controller. 

You can do the same for the switching frequency (determines motor speed), but at 400 Hertz for the switching frequency for the top speed of the motor, you might be able to get away with using the controller section to generate the frequency from 0-400 Hertz and sending it by copper wires to the power section.


----------



## Dan Frederiksen (Jul 26, 2007)

exactly how much do you imagine a <20kHz 5v pwm signal will be distorted over 20cm Dennis?


----------



## ecvs (Mar 4, 2008)

PWM signals are low voltage signals Dennis. Typically they are ttl level going into the drivers. If you are running a long distance perhaps you would have loss. But in an EV its not likely to even worry about it. Usually the PWM will be very close to the driver section. I would shield it with coax to cut down on noise emmisions. 
Tom


----------



## ngrimm (Oct 19, 2007)

I wish I had something to contribute to the project but I don't know anything about programming the micro controllers. I don't know if it would help but I think I could get a 1-2 hp 24 volt dc pump motor from a forklift in my area and donate it to the cause. Norm


----------



## Dennis (Feb 25, 2008)

Dan Frederiksen said:


> exactly how much do you imagine a <20kHz 5v pwm signal will be distorted over 20cm Dennis?



I tested about 20cm of non shielded, non twisted wire pairs at 15KHz, 5 volts and varied the duty cycle from 5% to 90% with my function generator. The output showed no ringing nor did it show any trailing or leading edge voltage spikes on my oscilloscope.

I even used a 102pF capacitor as a load and it still did not show any ringing ...

So yeah you proved a point....



> PWM signals are low voltage signals Dennis. Typically they are ttl level going into the drivers. If you are running a long distance perhaps you would have loss. But in an EV its not likely to even worry about it. Usually the PWM will be very close to the driver section. I would shield it with coax to cut down on noise emmisions.
> Tom


Well my real world testing proved your point well for transistor-transistor logic signal. Shielding would not be a bad idea as at least it can help prevent interference..


----------



## Dan Frederiksen (Jul 26, 2007)

good test Dennis. I was merely extrapolating from busses on motherboards with similar signals running many MHz. from that I didn't expect them to really be fragile. 
If I were to separate into two sections I would probably keep the driver on the low voltage side and send the gate line over wire to the power section. shouldn't be a problem either.


----------



## Madmac (Mar 14, 2008)

Dennis was correct, increasing the length of the drive cables introduces potential problems. The signal will be distorted by two mechanisms. one is the cable itself acts as it acts as both inductor with capacitance, if not carefully designed this can introduce oscillations on the fast switching edges (remember this is more than a logic signal as it is driving an LED). To see this on a scope you would need a bandwidth of 500Mhz upward. By adding a small value resistor or ferrite bead to the correct point this can be damped. 
Secondly there can be coupling from the high voltage power signals by virtue of dv/dt or rate of voltage change. If the correct choice of components is not used and care taken in layout coupling can again cause oscillations lasting a few 10's of nsecs that can lead to early failure of the switching device. (this is why you get specific opto's and DC/DC converters for these applications to reduce the effects but they will effect everything in the circuit if care is not taken)


Had a quick google for some documents that show up this problem. Most application notes from power FET or IGBT vendors mention in passing. The document at https://circle.ubc.ca/bitstream/2429/273/1/ubc_2008_spring_zhang_yong.pdf
does show what can happen.

Doing a DC chopper the effects will be easy to mask, in an AC inverter where one device is switching on as the other switches off any problems will show up a lot more.

Some problems can be investigated with an accurate Spice model of the switch taking into account strays. The rest of the problems can only be found when you build the prototype. If it was that easy to build inverters everybody would do it.

Madmac


----------



## Dan Frederiksen (Jul 26, 2007)

Madmac, I don't believe you for a second but perhaps you could point out on which page out the 99 there is in the pdf that the problem is shown


----------



## Madmac (Mar 14, 2008)

Would suggest you read chapter 5 although there are a few other references. I only skim read it so may have missed a few other things.

Madmac


----------



## ecvs (Mar 4, 2008)

The drive side is isolated by opto coupling on any good design to the driver section. There is no way any ringing is going to happen on the pwm signal. As long as you isolate your monitoring of voltage and current with hall effect transistors on your power drives, there is no way any problem is going to arise with the pwm signal. Typical signals are 20khz. You won't need a 500mhz scope to see the rising and falling edges of a pulse that slow. 
Tom


----------



## theboy16 (Feb 28, 2008)

will normal industrial 3 phase motors, typically operated at 60hz work with PWM?

Also, here in Canada, the standare voltage of these motors is 347/600 volt 3phase. how can we amplify our pack voltage (144-240v) to meet this requirement?

i think the US standard is 277/480 volts, but i could be wrong


----------



## Dennis (Feb 25, 2008)

> will normal industrial 3 phase motors, typically operated at 60hz work with PWM?


The problem with regular industrial 3-phase motors are/is the designer(s) do/did not foresee a user to use such a motor in variable speed application and therefore are not going to take that into account for the motor. If you do run a 3-phase motor that the designer(s) intended for 60/50 Hertz line frequency then the result will be high harmonics and a very good chance of reducing motor life as the induced voltage from the high PWM switching speeds will cause insulation breakdown from the corona produced which heats up the insulation.

Now there are 3-phase motors call Inverter Duty rated which are intended to work with variable frequency drives that can be bought from the various motor manufacturers such as Baldor, GE, Marathon, Leeson, Reliance Electric, and US motors.


----------



## Madmac (Mar 14, 2008)

Tom
Would suggest you read chapter 5 and look at the scope traces of gate drive signals. Even in the best designed systems there will be a small amount of glitching in the drive signal. Parasitic oscillations can be difficult to trace.

The major cause of problems in any high power switching design, be it motor inverter, ups, switchmode power supply or sinewave dimmer (a product I am involved in the design of at the moment) is coupling due to the speed of the switching edge or dv/dt. This can easily be a positive feedback and create instabilities.

To keep heat dissipation as low as possible the switching device should switch quickly so that the transition thru the linear phase is as quick as possible. The faster the transition the higher dv/dt is.

As for a piece of wire 12 inches long or a PCB trace that long that is unterminated it can severely distort a signal if the edges are very fast as in high data rate applications, would suggest you read up on transmission line theory. This is not applicable to the drive of an inverter though.

The turn on time of a power IGBT should be less than 150 / 200 nsec. To see that the leading edge and trailing edge are correct needs a scope that will resolve 20 / 30 nsec. Even a 500Mhz scope will be slightly distorting the drive as that band width is its 3db point.

If you are testing a product out in the field then a 60Mhz scope would be fine to just check the drive looks OK, but that is not good enough to qualify a product in development.

Dennis

Modern motors are designed to filter the PWM drive in the windings. You can run a normal motor on an inverter if you use inductors to filter the drive (low speed still has issues). This adds greatly to the cost which is why inverter compatible motors were developed.

Madmac


----------



## Dan Frederiksen (Jul 26, 2007)

everything is pwm so yes it has to work somehow. raising the voltage can be done with a boost converter circuit.
afaik 3-phase voltage ends up a bit higher than the input DC voltage because AC sends the DC voltage out in opposing directions to make a bigger span than the DC itself


----------



## Dennis (Feb 25, 2008)

> Tom
> Would suggest you read chapter 5 and look at the scope traces of gate drive signals. Even in the best designed systems there will be a small amount of glitching in the drive signal. Parasitic oscillations can be difficult to trace.
> 
> The major cause of problems in any high power switching design, be it motor inverter, ups, switchmode power supply or sinewave dimmer (a product I am involved in the design of at the moment) is coupling due to the speed of the switching edge or dv/dt. This can easily be a positive feedback and create instabilities.
> ...



I pretty much agree with everything you said. I was not able to pick up any abnormalities with the test Dan wanted my to try with 20cm of wire with <20KHz PWM squarewave though. I do know at high frequencies of say 40KHz I most certainly will be able to pick up those leading or trailing edge voltage spikes as well as the ringing if any. My scope only cost about $800 so its not nowhere near as capable as a $15,000 60GHz model would be which would have no trouble showing leading or trailing edge voltage spikes on low frequencies.

I have a 1MHZ crystal oscillator TTL compatible that easily shows up the effects that parasitic inductance and capacitance can cause with waveform signals. The O-scope shows severe ringing of about 8 volts above 5 volts of the squarewave and some dips at about 3 volts below 5 volts of the squarewave.


----------



## ecvs (Mar 4, 2008)

Well time will tell. I have read the link and its chapter 3 that addresses noise, as well as chapter 5. Interesting reading. Apparently twisting the discreet wires will work to create some inductive reactance, if you have any issues with noise. I doubt it will become a large issue if you isolate everything from the power drive, with opto, and lems and using a totally seperate power supply for drive vs control circuitry. 
Now on another note. 
I'm calling on all the fellows/gals if any on here who are involved in making their own homemade controller to share what they have information wise. I would put your information in a separate file on the yahoo group called evcs (stands for electric vehicle control system). This may help you as people will comment and give their advice on what you have going on. I have put the beginnings of my design on there as well as an open source circuit for a 3 phase motor controller. 
Please contact me through my hotmail address... [email protected] if you would like to submit your design to me I will make sure it gets uploaded on the yahoo group evcs.
Tom


----------



## TheSGC (Nov 15, 2007)

I still haven't gotten my schematics consolidated yet. Hopefully tonight I will have something scanned in and I can post it. Just a quick specs of the controller: 24 to 144 Volts, 275 AMPS limited, IGBT technology, 2 KHz operating frequency, and mostly out of Radio Shack parts.

I have a PIC programmer on the way and a few PIC18F2331 that I will use for my final controller, that will hopefully include so many features it will be rediculous. I custom built my IGBT driver, and it works quite nicely too, and that will be in my shematic sheet.

Does anyone know what size the main capacitor should be in a controller? In uF I mean. Right now I have two 200 Volt 680uF capacitors in parallel and I think its overkill.


----------



## ngrimm (Oct 19, 2007)

Don't know if it applies but my Curtis 1204x which is 35 volts @ 400 amps has fourteen 1000 uf caps on the output. Norm


----------



## Dennis (Feb 25, 2008)

Those capacitors are there so that as the MOSFETS or IGBT's switch into conduction mode to allow current to flow to the motor, the sudden current draw does not cause severe electrical noise when using filtering capacitors which IT WILL if there are no capacitors to discharge their charge when a sudden current surge is needed. Try going from 0 amps to 300+ amps in 250nS to 0 amps again to see the effects it has on the rest of the electrical system if no capacitors were used!!!!!!


----------



## Madmac (Mar 14, 2008)

Remember to select the right characteristic capacitors, ie. low ESR and high ripple current (this does equate to being the expensive types). The wrong type of capacitor will be more or less useless even if the voltage and value are correct.

Madmac


----------



## Dan Frederiksen (Jul 26, 2007)

Madmac, do you know a low esr high current cap product line?


----------



## TheSGC (Nov 15, 2007)

I've had a hard time figuring out the capacitors on the input line. I don't think using capacitors on the output of the IGBT is a smart thing since it would reek havok on the out voltages to the motor. At least that's what I have read, although is works nicely on dampening the noise from the controller.

So what I have done is taken the large caps from ATX power supplies since they are PWM based and should be able to handle the pulses, and I stuck them on the battery +.- of my controller.


----------



## Madmac (Mar 14, 2008)

Dan
Most manufacturers do a product line that meets the requirements.
I usually spec Nichicon as they have a reputation for reliability and price is mid range. Check out the QR range (or the NW)

http://www.nichicon.co.jp/english/products/alm_larg/list_f.htm

Madmac


----------



## epyon (Mar 20, 2008)

Do you still need a geine pig . I have the car , a 94 Lincoln Mark 8 . I'm not the best with electronics , but I'm the best with mechanics . P.M me and let me know so we can talk . If you need to , I'll send the car to you with the motor and trany put in (AOD FORD) if needed .


----------



## ecvs (Mar 4, 2008)

For the members here who are also members of the yahoo group evcs, design files from the powerrex site have been added that are pertinent to the VLA500 series IGBT drivers.
Tom


----------



## Dan Frederiksen (Jul 26, 2007)

epyon, when you say you are the best with mechanics does that mean you can make the adapter between the motor and the transmission?
both the mount and the coupling of the motor axel and clutch plate


----------



## aeroscott (Jan 5, 2008)

picked up a mitsubishi FX0N-40MR-ES/UL and FXon-8EYR-ES/UL, This is a plc used to control 2 dc low power gear motors in a label machine . any input ? thanks, john


----------



## epyon (Mar 20, 2008)

Dan Frederiksen said:


> epyon, when you say you are the best with mechanics does that mean you can make the adapter between the motor and the transmission?
> both the mount and the coupling of the motor axel and clutch plate


I can make plates for engines , but this is my first electric car . I have built COBRA kit cars and and lots of street cars with different engines and tranys for people and they still work fine . I haven't done a electric before but it can't be that off the norm . But direct-drive is what I really want first .


----------



## ecvs (Mar 4, 2008)

For the members of the yahoo group evcs----
3 members are talking about the powerex driver boards and 1 for sure is thinking of using a BG2B board, so I thought I'd better put this thread together. I hope you all use the BG2A board... read why. 
I have uploaded into the files section two driver boards. BG2A &
BG2B. 
The BG2B is rated up to 400 amps and the BG2A is rated up to 1400
amps. Both are rated for 2500 Volts. With either board you can run up to 3 IGBT's in parallel. This means the BG2B tops out at 1200 amps, while the BG2A tops out at 4200 amps....yikes!
Both are available from powerex built up or bare board and you do the
work of building and obtaining discreet components.
The BG2A is able to run at frequencies around 20khz while the BG2B I
believe is for slower switching speeds. I am still waiting on a BG2A
board to come in for my first design. I'm told approx 56 bucks,
although I'm getting a freebie (maybe that's why its taking so
long). I think that is quite reasonable pricing for what you get.
Desaturation protection, short circuit protection, gate surge
protection, input surge protection and opto isolation from PWM to
driver. Both boards are roughly the same price, therefore, I would go with the BG2A and this will leave yourself wide open to use much higher power IGBT's if you need it for speed/acceleration for your EV.
My first system will likely be interfaced with 144 volt battery pack,
and I would like to use two IGBT modules that have a 250 volt/600 amp rating (powerex CM600HA-5F) in parallel giving a total of 1200 amps possible. This should provide a decent acceleration. If I need a third one its just a little more plumbing of the bussbar and a few more components to bump it up to 1800 amps.
Tom


----------



## ngrimm (Oct 19, 2007)

That sounds like a great setup. Are you able to post pics or links? Norm


----------



## ecvs (Mar 4, 2008)

Pics will be posted on the yahoo group once we get the parts and as the whole system comes together we will be putting a complete package of information together for those who wish to build a similar unit. 
The yahoo group can be found as evcs. We have a 300 hp system on there and a lot of information on the various powerex parts that will be used once we get them. 
Tom


----------



## aeroscott (Jan 5, 2008)

tom, I can't open the files need to find the program that created it. john stubbe


----------



## ecvs (Mar 4, 2008)

The files I think are mostly word documents. Perhaps try again. If it doesn't work there is also a link to the information package on the yahoo group links to circuit cellar link is called AC drive controller
I know yahoo has been having some issues with people accessing various areas lately. They say they are working on it. Hopefully it gets cleared up soon. I did have another member respond to me that he was able to open all files no problem.
Tom


----------



## aeroscott (Jan 5, 2008)

thanks tom , I have all the circuit cellar files . I was thinking of the vls500 or something like that , its Micros top preforming board . A little more money but will handle the 1000 amp igbt . I think I need six for the 3 phase drive .


----------



## Madmac (Mar 14, 2008)

The desire seems to be to get the highest drive current possible. It is quite easy to design an output stage that will do 20,000 Amps. But why?

The down side to increasing the output current is two fold. Firstly the efficiency of the drives is not as good, it is easier to get for example very low switching losses on a 300 or 400 amp drive at an exceptable price. Secondly, nearly all battery chemistries are damaged each time a high current peak is drawn. While the individual decrease in capacity every surge is very small it will add up to wasting significant battery life. Even if you have a battery pack of 100AHr with 10C max. discharge rate limiting the current to 400 Amps instead of 1000Amps will give significantly longer battery life. If you are drag racing then the challenge is the reverse, battery life and cost are not the same targets.

The current draw for modest acceleration should be the target with designing the most efficient output stage to get the longest battery life (and greatest range per charge). Many commercial electric vehicles and hybrids deliberately limit the rate of acceleration to avoid damage to the batteries.

Madmac


----------



## ecvs (Mar 4, 2008)

The open source controller we are designing on yahoo will be able to have any IGBt up to 1400 amps and 3 in parallel would give 1400 X 3. I'm not planning on using IGBT's that big for my pickup truck conversion. The point of making the design able to handle that high an IGBT current is so it is universal. For those that wish to drag race and for those who don't need that much power, they would use a smaller current rated IGBT. This also allows anyone to build the controller and try it out with various IGBT's to see what sort of performance they like. If they need to move up the current to get more take off speed then they are only an IGBT change away from doing that instead of redesigning the driver section. This is why I chose the BG2A driver board from powerex.
Tom


----------



## Dan Frederiksen (Jul 26, 2007)

IGBT, diode and caps but yes. the 3 parts in the power section.
also, it's my impression that even the module IGBT wont do their rated current continuously. I don't have hard data on it but that's what I hear. maybe half, also depending on switching frequency and probably varies from product to product. voltage drop, etc


----------



## aeroscott (Jan 5, 2008)

Dan Frederiksen said:


> IGBT, diode and caps but yes. the 3 parts in the power section.
> also, it's my impression that even the module IGBT wont do their rated current continuously. I don't have hard data on it but that's what I hear. maybe half, also depending on switching frequency and probably varies from product to product. voltage drop, etc


Dan , that's what I understand too . this large power has additional metal working and battery dump loading ideas behind it . I also like real fast cars .


----------



## Madmac (Mar 14, 2008)

The quoted collector current is a maximum steady state parameter. The actual max current will depend on cooling and the switching conditions. 

Taking DC as an example. 
For a 400 amp device the VCEsat is a max value of 2.7 volts. The dissipation is 400 x 2.7 watts or 1080. The device has a thermal resistance of .18 degrees C per watt, and a typical heat sink will add .04 for junction with thermal paste and .2 for the heat sink. A total of .42 degrees C per watt. Multiply by the 1080 watts needed to be got rid of and the temperature rise will be .42 x 1080 =453.6 degrees C. The data sheet shows that the max die temperature is 175 degrees C. So to limit the the temperature to max the current must be reduced to 175/453.2 x 400 = 154 amps.

In the very simple case of DC the max current would be around 150 Amps. Doing the same for dynamic conditions of high speed switching is much more complicated as the worst case switching speed is needed to analyse the dissipation as the device switches on and off (there is a small transition thru a linear region where the voltage across the device is varying as the current increases resulting in significant dissipation each transition. This is one of the trade offs for the switching frequency, the lower it is, the less transitions, the lower the power dissipated (and why the aim is to switch cleanly on and off as fast as possible)

Madmac


----------



## aeroscott (Jan 5, 2008)

Madmac , thanks for the info , I was thinking of oil cooling the entire power section . But don't know about oils effect at high temps on the parts . I had found a site that made oil and water cooled dynometers(induction generators ) for jet engines etc . All different sizes from 7" x 12" and up . the water cooled was just a jacket on the stator , when oil cooling was added they got about 2.5 x the hp of water cooling . So do you think oil cooling the top side of the igbt's would help much with water cooling the bottom . john


----------



## xrotaryguy (Jul 26, 2007)

*Homemade Controller Design*

I finally got around to drawing a circuit board layout for a DC motor controller. I plagiarized from Dan's design pretty heavily. Would you guys take a look at this thing and let me know if this makes any sense? Thanks.


----------



## Dan Frederiksen (Jul 26, 2007)

*Re: Homemade Controller Design*

it's not plagiarism. it's freeware. meant to be copied and modified.
I'm actually not sure but I think that the freewheel diode needs a similar current capability as the transistor. I think you can use another CM600 for that and use its reverse diode. unfortunately a single CM600 can't serve both functions


----------



## xrotaryguy (Jul 26, 2007)

oic, so I should use a diode like this one. Powerex makes it and the data sheet specifically says "freewheeling diode".


----------



## ww321q (Mar 28, 2008)

Wow ! Xrotaryguy and Dan Frederiksen . I just might be able to put that together ....cool!....J.W.


----------



## theboy16 (Feb 28, 2008)

that looks very cool and feasible. things started looking a little hairy for me a few weeks back, when i got lost with all this micro mumbo jumbo. You guys are obviously working very hard at this project, and it is greatly appreciated from everyone else who doesn't understand the micro stuff. 

Keep up the great work!!!

Steph


----------



## aeroscott (Jan 5, 2008)

I found some Trace grid tie inverters 5 kw will not work as stand alone must have grid power going in (no ul listing). they want 200 each maybe we can use some parts . they also have some water cooled ones ( scraping out ) can't remember the name i will pull the heat exchangers (al plate / copper tube ) I'll get the name /model . there may be gate diver and other parts that anyone can think of . not ul listed so can't be grid tied ( legally ). I'll grab the igbt's also , might be good air conditioning driver .


----------



## xrotaryguy (Jul 26, 2007)

aeroscott said:


> I found some Trace grid tie inverters 5 kw will not work as stand alone must have grid power going in (no ul listing). they want 200 each maybe we can use some parts . they also have some water cooled ones ( scraping out ) can't remember the name i will pull the heat exchangers (al plate / copper tube ) I'll get the name /model . there may be gate diver and other parts that anyone can think of . not ul listed so can't be grid tied ( legally ). I'll grab the igbt's also , might be good air conditioning driver .


Nice, gotta love scrap parts. 



> that looks very cool and feasible. things started looking a little hairy for me a few weeks back, when i got lost with all this micro mumbo jumbo. You guys are obviously working very hard at this project, and it is greatly appreciated from everyone else who doesn't understand the micro stuff.


Just read this thread about 90 more times. That's what I did  I'm learning as much from this thread as you are.


----------



## aeroscott (Jan 5, 2008)

xrotaryguy said:


> Nice, gotta love scrap parts.
> 
> 
> Just read this thread about 90 more times. That's what I did  I'm learning as much from this thread as you are.


 xrotary, my head is spinning too. check micro's web site videos to teach you in depth. I go over them every 2 weeks or so to refresh . there's about 50 hours worth in 25 minute long units .


----------



## ww321q (Mar 28, 2008)

aeroscott what is the web sight for micro ? thanks ........J.W.


----------



## aeroscott (Jan 5, 2008)

aeroscott said:


> im doing the same thing.on evdl i(about Jan.2,08) found a link to circuitceller.com/microchip2007/winners/mt2291.html this is 100 hp 3 phase motor controller.it can also be a dc controller with some mods. link from that to (microchip.com/motor)app notes ,web casts,etc.it will take 100's of hours but microchip all the info you can absorb.school on the net!its a huge site.


from post #89 the microchip.com site in archived somthing ? thats web casts .


----------



## theboy16 (Feb 28, 2008)

*Re: Homemade Controller Design*



xrotaryguy said:


> I finally got around to drawing a circuit board layout for a DC motor controller. I plagiarized from Dan's design pretty heavily. Would you guys take a look at this thing and let me know if this makes any sense? Thanks.


what's the square device with the hatches? the HV cable from the IGBT runs through it; looks like it senses something...


----------



## TheSGC (Nov 15, 2007)

That's a Hall Effect Current Sensor.

What gauge wire are you using to connect the IGBT to the connectors on the casing? I am thinking about 8 gauge, but I am unsure. It's a very short distance, so it doesn't have to be huge I think. 

How does one decide on the freewheel diode on the motor? I found that all that it needs is an Idiode pulse of your motor AMPs.


----------



## ecvs (Mar 4, 2008)

Madmac,

Lets see if we are on the same page with the operating temperatures... I think maybe you slipped a digit but I could be wrong... lets take a look at a 1400V 1000 amp IGBT powerex # CM1000HA-28H here's the link to the spec sheet...http://www.pwrx.com/pwrx/docs/cm1000ha28h.pdf
Ok now the Vsat you can see on this particular IGBT is 3.1 volts (the higher the current the worst this rating gets)
If we were to run it wide open 1000 amps (yikes) we would develop 3100 watts. Now on the same spec sheet the device increases .018 per degrees C/Watt... now if my math is right (and it's not always)we are in and around 55.8 degrees C . Worst than this is the freewheel diode with a .050 degrees C/Watt. Now with pwm your going to have a duty cycle that has an extensive range so it will be somewhat better than DC . Anyways... check over my calculations and see if I'm on the same page... I understood what you were saying ... just wondering if you slipped on that .18 rating per degrees C/W... 
My design would never run an IGBT wide open anyways... I plan to limit current at 600 amps. I did talk with a powerex rep named John Donlon on this very subject today and he said the delta gate temp should no be more than 60 degrees C if you want to have a controller that lasts 20 years.
I believe it would be best to cool the IGBT with water or oil to keep that temperature down as low as we can. Neuroticart is doing just that as he has been explaining on the yahoo group. Apparently he is boring out some aluminum and plumbing it.
Tom


----------



## aeroscott (Jan 5, 2008)

tom , on the oil cooling I was thinking of flooding the power box so everything in there is cooled like x-ray equipment . then water cooling the bottom . I'm going to see some water cooled grid tie inverters on Thursday being junked out . these are 4or 5 kw ,I was thinking of 6 cooling units for one of our controllers , 100 units to be junked .


----------



## Madmac (Mar 14, 2008)

ECVS

You are correct with the thermal resistance on the part you quoted. This figure is very low and not typical of power devices. (care does need to be taken in reading this data sheet, see comment below). For example look at the CM400DU-12NFH part used in the 3 phase inverter mentioned earlier this thread (either the Powerex or the Mitsubishi part) and the figure is .13 C/W. Lowering the thermal resistance increases the cost of manufacture, as with all engineering things a trade off is made. 

I gave the example to show that the manufacturer states a limit (max or min) figure for all parameters, that does not mean they all apply at the same time. It is also wise to design for the max figure on Vsat. Some parts may have this value and a design should work with all parts supplied. That makes a small increase from 3.1 to 4.5 volts.

You have only taken the thermal resistance from the die to the case and not included a figure for the thermal paste layer or the heatsink itself.

Finally the data sheet does not specify exactly what they are measuring. It may well be the die to internal heatsink. If you look at the data sheet for the device above you will see the data is a little more detailed. Normally the Tc reference point(s) is shown on the drawings.


Designing for 60C is fairly standard for all consumer type products and good advice. A quick check is at that temp you can just about keep a finger on it (assuming it is not live!!).

Madmac


----------



## ecvs (Mar 4, 2008)

Aeroscott,

Just wondering how big these scrap units are? Sounds like an excellent idea for cooling if its the right size. Any idea on cost? 
Also you mentioned something earlier about pic micro having a 50 hour online course or something like that... can you give the link details?
Thanks
Tom


----------



## aeroscott (Jan 5, 2008)

ecvs said:


> Aeroscott,
> 
> Just wondering how big these scrap units are? Sounds like an excellent idea for cooling if its the right size. Any idea on cost?
> Also you mentioned something earlier about pic micro having a 50 hour online course or something like that... can you give the link details? left side of link " archived quick list ", same stuff , better layout
> ...


 tom no idea on size / coast ,will see tomorrow . http://techtrain.microchip.com/webseminars/archived.aspx


----------



## aeroscott (Jan 5, 2008)

inverter water cooled igbt , picked up 10 units yesterday . alu box heavy plate on the igbt side , welded / press braked thin alu box 4'' x 9" x 1". easy to make . will post pictures soon .


----------



## wakinyantanka (Apr 8, 2008)

Having read this post several times I have one question.Why couldn't we use a curtis 1505 controller and use the voltage regulator in Dans schematic to provide it with the proper voltage to operate and remove the mosfets that are on the board and build a separate air cooled unit that houses what ever amperage and voltage requirement mosfets we need?
I have one of these little units and looking at the board itself it has all the individual components you guys are listing in the schematic and then some.
After looking at the websites selling them it also looks to have several features some of you where wanting for your controllers.
Please let me know if I'm off base here as I am new to the controller scene.


----------



## aeroscott (Jan 5, 2008)

hi all had a light day or should I say I played a little . went over to U C Davis to talk to the electric car program guys . well ran into a grad student and started to ask about building controllers , oil cooling motors and talked about the silicon battery development . in there program they do not open the controller box may be from ac propulsion . the professor said oil cooling was so complicated that it would take 800 units to get it right . he did say to check the library . I wonder what they study in that program . they do not build controllers or motors .


----------



## Dan Frederiksen (Jul 26, 2007)

wakinyantanka, assuming my design works (which is not guaranteed) why not just use that?


----------



## xrotaryguy (Jul 26, 2007)

aeroscott said:


> I wonder what they study in that program . they do not build controllers or motors .


haha, too funny. I get the same feeling sometimes talking to the instructors at my school. I try to run a couple of ideas past them, and without fail, they well me the conventional way to do it. 

If I talk to my class mates, they have all kinds of crazy ideas... many of them very good. 

Oh well, I guess that's the way the education system works. You learn enough to prove to potential employers that you're interested.

Ok, back on topic. I made a couple of changes to my speed controller. Namely, changed the free wheeling diode to a unit that should be better suited to the task. I also enlarged the text where I could. whaddya think?


----------



## wakinyantanka (Apr 8, 2008)

Dan Frederiksen said:


> wakinyantanka, assuming my design works (which is not guaranteed) why not just use that?


Hi Dan,
I guess my thought is that we know these little units work for small motors why not not do some performance upgrades and boom we have it, no worrying about programing or writing code or any of that. I mean why reinvent the wheel, these little things are cheap, the upgrade components are cheap, we can isolate are high power mosfets and rectifiers to reduce noise and I think,(could be wrong because I'm no expert), have a rock solid controller thats cheap and reliable.
That being said, I'm doing a scratch build from the ground up, my own design of vehicle, composite monocoque structure, blah, blah, blah, so I need the microcontrollers for lighting, instrumentation, on board generator control and so on. Those critters are very useful and I plan on writing code for them, but it's far easier to write code to turn on lights and monitor voltage for the battery pack than it is to control a motor. In my humble opinion, and believe me its just opinion I do not want to ruffle feathers or upset anyone as my expertise is in building drag racing gas powered cars not electric cars. So by all means, anyone who can enlighten me on this please do so. Time is money and I want to focus on finishing my body and driveline components.


----------



## Madmac (Mar 14, 2008)

xrotaryguy

C1 will need to be a low ESR cap. A 100nF to 1mfd ceramic cap in parallel would also be a good idea. The current sensor output could almost certainly do with a R/C network to filter noise. Decoupling caps on the CPU and output of PSU's would help as well.

Circuit is difficult to follow. Usually the circuit symbol is drawn to show the component in an easy way to follow, not a physical layout. Also labeling a pins function is also useful.

Madmac


----------



## wakinyantanka (Apr 8, 2008)

wakinyantanka said:


> Hi Dan,
> I guess my thought is that we know these little units work for small motors why not not do some performance upgrades and boom we have it, no worrying about programing or writing code or any of that. I mean why reinvent the wheel, these little things are cheap, the upgrade components are cheap, we can isolate are high power mosfets and rectifiers to reduce noise and I think,(could be wrong because I'm no expert), have a rock solid controller thats cheap and reliable.
> That being said, I'm doing a scratch build from the ground up, my own design of vehicle, composite monocoque structure, blah, blah, blah, so I need the microcontrollers for lighting, instrumentation, on board generator control and so on. Those critters are very useful and I plan on writing code for them, but it's far easier to write code to turn on lights and monitor voltage for the battery pack than it is to control a motor. In my humble opinion, and believe me its just opinion I do not want to ruffle feathers or upset anyone as my expertise is in building drag racing gas powered cars not electric cars. So by all means, anyone who can enlighten me on this please do so. Time is money and I want to focus on finishing my body and driveline components.


C'mon guys no other input? I need to know if this is a viable option.
Thanks


----------



## TheSGC (Nov 15, 2007)

wakinyantanka said:


> C'mon guys no other input? I need to know if this is a viable option.
> Thanks


I would so most likely not a viable option. Most controllers have the current limiting built into it, so changing the components would do nothing. At that point the amount of work required to properly upgrade the controller would be so much that it would be easier to either build your own from scratch, or just buy a new larger one.

BUT I am spectulating here. I would love to get my hands on a dead 48 volt controller and take a good look myself and see if there is an easy way to increase the voltage and amperage.


----------



## Dan Frederiksen (Jul 26, 2007)

I don't really know enough about the Curtis controllers to say but yes I'd also say the current limiting is hardwired. you could still increase the voltage limit but that might have problems too. you could try changing the fet, diode and caps to higher voltage and run it. it's cheap so wont be a disaster if it fails.

one thing worth checking is the capacitance of the FETs. if the new FETs have higher capacitance it might overload the driving circuit because the average current to fill and empty the gates is too high. also the new FETs might need higher driving voltage but not sure.
it should be possible somehow of course. even changing the current limit. but in the long run I really believe it's better to have a nice clean new design so you don't need to find a controller that costs more than all the rest put together.


----------



## wakinyantanka (Apr 8, 2008)

Dan Frederiksen said:


> I don't really know enough about the Curtis controllers to say but yes I'd also say the current limiting is hardwired. you could still increase the voltage limit but that might have problems too. you could try changing the fet, diode and caps to higher voltage and run it. it's cheap so wont be a disaster if it fails.
> 
> one thing worth checking is the capacitance of the FETs. if the new FETs have higher capacitance it might overload the driving circuit because the average current to fill and empty the gates is too high. also the new FETs might need higher driving voltage but not sure.
> it should be possible somehow of course. even changing the current limit. but in the long run I really believe it's better to have a nice clean new design so you don't need to find a controller that costs more than all the rest put together.


Hi Dan,
Looking at mosfets in general don't they all use the same gate driver voltage, 0-15v? My thought is that we use a low power source, dc/dc convertor to get the curtis the proper operating voltage so we are not overloading it or asking it to do something its not already doing. Then replace the 5 fets that are in the board with correct # of fets for our personal application. The rectifier diodes and all the high amperage components would then be in a separate box and we wire the curtis to activate the replacement fets as if it is the driver instead of the whole controller.
Or should I forget all this and just build my own driver and controller.
I think microchip has the basic code already written for a dc motor, just need to cut and paste.


----------



## xrotaryguy (Jul 26, 2007)

Madmac said:


> xrotaryguy
> 
> C1 will need to be a low ESR cap. A 100nF to 1mfd ceramic cap in parallel would also be a good idea. The current sensor output could almost certainly do with a R/C network to filter noise. Decoupling caps on the CPU and output of PSU's would help as well.
> 
> ...


Super! thanks for the input. I will reference some more circuit diagrams as I work on my understanding of controllers. Hopefully my next diagram will be easier to follow or more conventional.


----------



## ngrimm (Oct 19, 2007)

Hello wakinyantanka.
If you look at the topic below that I started a while back, I proposed upgrading a curtis pmc controller from a forklift. I still have one of mine apart and haven't given up on increasing the voltage. At least I have a reverse engineered schematic. Is there a schematic available for the controllers you are referring to? Norm
http://www.diyelectriccar.com/forums/showthread.php/curtis-controller-voltage-upgrade-9908.html


----------



## wakinyantanka (Apr 8, 2008)

ngrimm said:


> Hello wakinyantanka.
> If you look at the topic below that I started a while back, I proposed upgrading a curtis pmc controller from a forklift. I still have one of mine apart and haven't given up on increasing the voltage. At least I have a reverse engineered schematic. Is there a schematic available for the controllers you are referring to? Norm
> http://www.diyelectriccar.com/forums/showthread.php/curtis-controller-voltage-upgrade-9908.html


Hey ngrimm,
No I do not have a schematic for it. My thought was just to use it as the driver board and add the fets for my application. I'm thinking now I'll just forget it and buy the components and put one together myself. It doesn't look terribly complicated and from what I'm reading microchip has code for dc motor control already written.


----------



## wakinyantanka (Apr 8, 2008)

Hey guys,
Just got off the phone with a motor driver board manufacturer and he said that my idea would not work because the higher voltage mosfets require a driver that is compatible with them and these smaller boards can't handle it.
Oh well, just a thought.....


----------



## Dan Frederiksen (Jul 26, 2007)

did you ask how they were incompatible?
I'm not sure he necessarily knew exactly what he was talking about


----------



## wakinyantanka (Apr 8, 2008)

Dan Frederiksen said:


> did you ask how they were incompatible?
> I'm not sure he necessarily knew exactly what he was talking about


Yes, he said that the high voltage mosfets we require should be driven by a high voltage gate driver like the fan7361 which is capable of charging and draining multiple high power mosfets. This device is not on the board I have or any other low voltage system. Apparently, the gate driver and mosfets must be capable of handling similar voltages.


----------



## wakinyantanka (Apr 8, 2008)

Hey Dan,
What is the device in your design that is connected to the low voltage supply module? It is listed as; L1 1mh.


----------



## wakinyantanka (Apr 8, 2008)

Does anyone know if the free wheel diode amperage has to match the amperage of the mosfets or igbts that are used? Also, what does the free wheel diode accomplish?
Thanks
Hate to be a pest but just want to understand as much as I can about building these units.


----------



## TheSGC (Nov 15, 2007)

wakinyantanka said:


> Does anyone know if the free wheel diode amperage has to match the amperage of the mosfets or igbts that are used? Also, what does the free wheel diode accomplish?
> Thanks
> Hate to be a pest but just want to understand as much as I can about building these units.


 
I have been searching for this answer too, and so far then only thing I have found is that the Idioide Pulse should be equal or great to the max motor current. So for instance I have chosen two diodes from Radio Shack that have 300 AMP pulse each for my 250 AMP limited controller. 

The freewheel diode stops the reverse voltage created by a collasping magnetic field, and allows the motor to spin more effectively.


----------



## wakinyantanka (Apr 8, 2008)

Dan,
Doing some more research today and realized the driver that you have listed in your circuit schematic will not work to drive the mosfet/igbt you have listed.
Apparently we will be required to use a high side mosfet driver that will handle the high side voltage capability of the system. Most high side drivers can handle up to 600v. The unit listed will handle high current but is a low side driver and would not be able to handle voltages above 48v.

High side direct drivers for N-channel devices
The majority of power supply applications utilize
N-channel MOSFETs as the main power switch
because of their lower price, higher speed and
lower on-resistance. Using N-channel devices as
a high side switch necessitates a gate drive circuit
which is referenced to the source of the
MOSFET. The driver must tolerate the violent
voltage swings occurring during the switching
transitions and drive the gate of the MOSFET
above the positive supply rail of the power
supply. In most cases, the gate drive voltage must
be above the highest DC potential available in the
circuit. All these difficulties make the high side
driver design a challenging task.

Source: Design And Application Guide
For High Speed MOSFET Gate Drive Circuits
By Laszlo Balogh

http://focus.ti.com/lit/ml/slup169/slup169.pdf


----------



## Dan Frederiksen (Jul 26, 2007)

you dare question my design? : )

what makes you think that we need a high side design?


----------



## theboy16 (Feb 28, 2008)

although this micro stuff is over my head, i enjoy following in, and would like to thank everyone who's working so hard on it, so that the rest of us can save a whack of money, and have a custom controller

Steph


----------



## wakinyantanka (Apr 8, 2008)

Dan Frederiksen said:


> you dare question my design? : )
> 
> what makes you think that we need a high side design?



Not questioning the design, questioning the ability of the driver to handle voltages above 48volts. 
I'd hate to put it together only to have it cook on first real world test.


----------



## ww321q (Mar 28, 2008)

I wonder if this is usable ? On another page it said 1200v 600a usable range
http://www.pwrx.com/pwrx/docs/m57962.pdf
these are only $20........................J.W.


----------



## ww321q (Mar 28, 2008)

the other page..................................................J.W.
http://www.pwrx.com/Result.aspx?q=m579


----------



## Dan Frederiksen (Jul 26, 2007)

wakinyantanka, I'm not an EE, I just read a chapter of a book and asked some questions to learn just enough to formulate the design. but as I understand it so far the driver doesn't need to handle the high voltage. the FET/IGBT does. the gate pin should not let high voltage into the driver so all it has to handle from what I know is it's own 0-15v signal. it's called low side driver meaning it's in the low voltage side of things. a high side driver doesn't handle more voltage but its span is 15v in the high end. for instance from 250v down to 235v. in a sense a high side drive has its ground on the + wire. doesn't really handle more voltage, it's just inverted as I understand it.
provided the gate current doesn't exceed the driver's ability and there are no stray voltage spikes in the circuit (which could be protected against if needed) I think the driver will work. I think it is designed to control a transistor that handles much more than 48v but I could be wrong


----------



## wakinyantanka (Apr 8, 2008)

Dan Frederiksen said:


> wakinyantanka, I'm not an EE, I just read a chapter of a book and asked some questions to learn just enough to formulate the design. but as I understand it so far the driver doesn't need to handle the high voltage. the FET/IGBT does. the gate pin should not let high voltage into the driver so all it has to handle from what I know is it's own 0-15v signal. it's called low side driver meaning it's in the low voltage side of things. a high side driver doesn't handle more voltage but its span is 15v in the high end. for instance from 250v down to 235v. in a sense a high side drive has its ground on the + wire. doesn't really handle more voltage, it's just inverted as I understand it.
> provided the gate current doesn't exceed the driver's ability and there are no stray voltage spikes in the circuit (which could be protected against if needed) I think the driver will work. I think it is designed to control a transistor that handles much more than 48v but I could be wrong


Hey Dan,

I guess the only thing to do is build a prototype and see what happens.
I am just learning this myself and was more than confused when I read the statement. I was thinking along the same lines as you until I read that article. Maybe I'll give it another read through to see if I misunderstood.

Also, what is the device labeled L1 1mH?


----------



## Dan Frederiksen (Jul 26, 2007)

that's an inductor. electric current has momentum which means once in motion it will continue until resistance slows it down. an inductor is a device that takes advantage of that simply by having a long wire similar to a heavy flywheel. the heavier the harder it is to change it's speed. the result is that it smoothes out the current flow. it cleans the pulsed supply coming from the rest of the circuit. actually the windings in the motor serves the same function for the power transistor which pulses. mH is milli henry. henry is a unit of inductance


----------



## wakinyantanka (Apr 8, 2008)

Dan Frederiksen said:


> that's an inductor. electric current has momentum which means once in motion it will continue until resistance slows it down. an inductor is a device that takes advantage of that simply by having a long wire similar to a heavy flywheel. the heavier the harder it is to change it's speed. the result is that it smoothes out the current flow. it cleans the pulsed supply coming from the rest of the circuit. actually the windings in the motor serves the same function for the power transistor which pulses. mH is milli henry. henry is a unit of inductance


Thanks Dan, where did you get the part?

Did we ever figure out if the free wheel diode amperage has to be the same as the total capacity of the controller?


----------



## aeroscott (Jan 5, 2008)

good find on the inductor. passed my pipe welding test. check out the evtech.org group a sub group of evdl devoted to ev electronics


----------



## ngrimm (Oct 19, 2007)

Hey Dan. Maybe I missed something but isn't the free-wheel diode part of the cm600ha24h module you are using? To quote the data sheet "Each module consists of one igbt transistor in a single configuration with a reverse connected super fast recovery free-wheel diode" Norm


----------



## Dan Frederiksen (Jul 26, 2007)

I buy most parts on digikey.com

I'm actually not certain about diode current but I figure they need to be the same. as I see it the diodes can have the same max current load all the time as the transistors, they just have the load when the transistors don't. if the motor doesn't swallow the energy the transistors can set 500A in motion at a <5% duty cycle and those 500A will then ideally run around the motor-diode circuit at near 100% duty cycle. as I see it


----------



## Dan Frederiksen (Jul 26, 2007)

ngrimm, unfortunately the diode often included in IGBTs is not wired right for this type of application. maybe it works out in AC controllers because they can serve as eachothers diodes. in the DC arangement it's largely useless as I see it so you need a separate one.

also I don't use the cm600. I bought two initially because they were cheap on ebay but I later learned that small components are much cheaper and I wanted a design that used only new parts so everyone could build it without having to get lucky on ebay. the cm600 costs 450$ new. equivalent power can be gotten for 1/10th of that in small components


----------



## wakinyantanka (Apr 8, 2008)

Hey guys,
Just wondering if anyone has thought about using adjustable linear regulators for low voltage supply. 
What would be the drawback/advantage to these?


----------



## Dan Frederiksen (Jul 26, 2007)

if they are like voltage limiters they waste a lot of energy. if the energy consumption is very small it can work though. dropping 250v down to 12v is only 5% efficient. but if you need just 1w you waste 19watt. (and will need appropriate cooling)


----------



## Dennis (Feb 25, 2008)

Speaking of inductors it might be wise to have an inductor inline to the motor connection to reduce ringing. A capacitor connected from *C*ollector to *E*mitter although will work is not recommended as it will affect the rise and fall time of the IGBT device which is not what is wanted when the intent of the device is being used as a switch rather than operated in its linear region which one who designs a motor controller wants to get out of that region quickly to prevent heat build up of the IGBT device. 


Here is how to measure any ringing that might be present on the device with respect to ground:


----------



## wakinyantanka (Apr 8, 2008)

Dan Frederiksen said:


> if they are like voltage limiters they waste a lot of energy. if the energy consumption is very small it can work though. dropping 250v down to 12v is only 5% efficient. but if you need just 1w you waste 19watt. (and will need appropriate cooling)


I'll try to find some specs on them and get them posted.

http://focus.ti.com/lit/ds/symlink/tl783.pdf

Let me know what you think.


----------



## wakinyantanka (Apr 8, 2008)

Dennis said:


> Speaking of inductors it might be wise to have an inductor inline to the motor connection to reduce ringing. A capacitor connected from *C*ollector to *E*mitter although will work is not recommended as it will affect the rise and fall time of the IGBT device which is not what is wanted when the intent of the device is being used as a switch rather than operated in its linear region which one who designs a motor controller wants to get out of that region quickly to prevent heat build up of the IGBT device.
> 
> 
> Here is how to measure any ringing that might be present on the device with respect to ground:



Dennis,
I'm going the igbt route as it looks like I can get what I need with one unit.
Also, Zilla is using them so they have to work well. Everything I've read says they work as well if not better than Mosfets at the 20-30khz range.
Would you have any suggestions as to developing an appropriate schematic?
I'll be using the ATMEGA-8 microcontroller for processing.
Thanks


----------



## Dennis (Feb 25, 2008)

I am not saying its bad to use an IGBT. I am saying that if you want your IGBT that you pay $300 for to not blow up on you that you should take the precautions to make sure ringing is not present or it can destroy it. All transistors whether they are IGBTs, Bi-polar or even MOSFETS have a maximum voltage they are rated for that if exceeded will destroy the device. Hopefully your motor should have enough inductance that ringing will be minimum. You will need to test your circuit to find out though. If you wish to not use an inductor then I suppose you can use a Metal Oxide Varistor connected between C and E of the IGBT transistor although if the ringing continues to exceed the MOV rating for long durations it can eventually cause the MOV to degrade or even fail catastrophically (catch on fire).


----------



## wakinyantanka (Apr 8, 2008)

Dennis said:


> I am not saying its bad to use an IGBT. I am saying that if you want your IGBT that you pay $300 for to not blow up on you that you should take the precautions to make sure ringing is not present or it can destroy it. All transistors whether they are IGBTs, Bi-polar or even MOSFETS have a maximum voltage they are rated for that if exceeded will destroy the device. Hopefully your motor should have enough inductance that ringing will be minimum. You will need to test your circuit to find out though. If you wish to not use an inductor then I suppose you can use a Metal Oxide Varistor connected between C and E of the IGBT transistor although if the ringing continues to exceed the MOV rating for long durations it can eventually cause the MOV to degrade or even fail catastrophically (catch on fire).


The unit I am using is rated at 1200v, 1000 amps continuous 2000 amps pulse width modulated. My system voltage will be 144v, so I doubt I will run into any overload problems.


----------



## Dennis (Feb 25, 2008)

Ringing can be many times higher in voltage potential than power supply voltage. Case in point, I built a 12 volt motor controller that had ringing in excess of 60 volts from the Drain terminal of the MOSFET with respect to ground. Luckily the MOSFET do not go boom when this occurred even though it was rated at a maximum of 40 volts. 

If you do build your motor controller, just be sure that the ringing is at least 2 times below the max working voltage of the IGBT for safety margin. If it were me I would still use an inductor to reduce the ringing or hope the motor inductance is sufficient for the damping of the ringing oscillations.


----------



## aeroscott (Jan 5, 2008)

does a larger motor have less ringing because of more material. a smaller motor with the same controller then would be prone to ringing . is this tuning a controller to the motor .


----------



## wakinyantanka (Apr 8, 2008)

Dennis said:


> Ringing can be many times higher in voltage potential than power supply voltage. Case in point, I built a 12 volt motor controller that had ringing in excess of 60 volts from the Drain terminal of the MOSFET with respect to ground. Luckily the MOSFET do not go boom when this occurred even though it was rated at a maximum of 40 volts.
> 
> If you do build your motor controller, just be sure that the ringing is at least 2 times below the max working voltage of the IGBT for safety margin. If it were me I would still use an inductor to reduce the ringing or hope the motor inductance is sufficient for the damping of the ringing oscillations.


Can you recommend a safe schematic to use for this application?
I found this over at osmc;
http://tech.groups.yahoo.com/group/osmc/files/DC%20control/

Looks like a very nice set up, although I do not need the full h-bridge as I'm using reverse in the transmission I have. It looks like this design will allow for the components to be interchanged to suit ones needs.


----------



## Dennis (Feb 25, 2008)

If the designer tested it and had no failures then give it a try. I guess you do not have an Oscilloscope? If not then just take the risk I guess.


----------



## aeroscott (Jan 5, 2008)

I found 500 meg hz scope techtronics said to run good at 490 meghz older with the slip in modules $350.00. is this over kill for our 20k hz controllers.


----------



## aeroscott (Jan 5, 2008)

Dennis , how would you build the inductor . i'm thinking it goes between the igbt and motor .


----------



## Dennis (Feb 25, 2008)

> I found 500 meg hz scope techtronics said to run good at 490 meghz older with the slip in modules $350.00. is this over kill for our 20k hz controllers.


A 500 Mhz Bandwidth Tektronix? They want $350 for it? Those scopes are about $8,000 new! Just one question though: did they calibrate it to NIST standards? I bought a Instek GDS806 for around $900 brand new. It's only 60 MHz Bandwidth and it picks up the ringing on waveforms very well. The one you are looking at is much better and can show up even more detail than my cheap one can.



> Dennis , how would you build the inductor . i'm thinking it goes between the igbt and motor .


I use a yellow/white painted toroid core with the motor wire connections wound around the toroid a few turns. In your case in using HIGH POWER, a little toroid is not going to do the job because it will saturate very easily from the large currents involved. I suppose you can test a toroid core out of a car audio amplifier that no longer works. They have large toroid cores in them for the DC-DC converter. Better yet, you can buy toroid cores.


----------



## wakinyantanka (Apr 8, 2008)

Lets not let this thread die. Anyone have any new info?


----------



## MPaulHolmes (Feb 23, 2008)

Greenflight said:


> You can pick up a 600A IGBT on ebay for pretty cheap... Might be a better solution than MOSFETs. I have one, but I'm not exactly ready to use it...


I got a good deal on 4 600amp IGBTs on Ebay. I've read a lot of their documentation, and they suggest keeping continuous current below 200amps per device. Fortunately, Powerex sells a cheap kit to help parallel 2 of those beasts.


----------



## MPaulHolmes (Feb 23, 2008)

Yes, Please thread, don't die! I just started my IGBT based controller about a couple weeks ago, and I'm going to need some help. Here's where I am right now:

I bought 4 1200v 600amp IGBTs on ebay for a total cost of $50.
I'm planning on paralleling 2 of them, and using the other 2 in parallel as free-wheeling diodes in parallel with the motor. I know, it's hard to parallel IGBTs, but Powerex designed a driver circuit (not just a driver) to make it a little more plug-and-play. The kit is called the BG2B. Just the Printed Circuit Board for the BG2B is $20. The other parts aren't too expensive.

I've been programming the Atmel ATMega16 using their free C software development environment. All the programming is still on the computer, since I haven't ordered the chip or ISP programmer for the chip yet. If anyone wants the software, I've heavily documented it, so it's pretty easy to read, and you can have it. It is a work in progress, though.

I'm trying to figure out the best way to monitor junction temperature of the IGBTs. I've gotten some good ideas from the EV Tech list, but I want a simple way to use a thermistor as input into one of the Analog/Digital Converter channels of the microcontroller to smoothly weaken the duty cycle if the IGBTs get too hot. Maybe I could put the thermistor on the heatsink? Suggestions?

I ordered 2 2.5 pound copper heat sinks when I thought I would only need 2 of the IGBTs. According to the Zilla guy, those are too tiny (ya, for his 2000amp beasts!!!), so I'm currently bidding on a 10 pound Aluminum heatsink designed for 6 1200v 200amp IGBTs, as well as a fan that hooks up to it. I was thinking about going with liquid cooling, but this is supposed to be a budget project!


----------



## MPaulHolmes (Feb 23, 2008)

wakinyantanka said:


> Thanks Dan, where did you get the part?
> 
> Did we ever figure out if the free wheel diode amperage has to be the same as the total capacity of the controller?


This topic came up on the EV Tech list, and according to Lee Hart (one of their top 2 or 3 experts, right up there with the Zilla guy), the answer to that question is "YES". He also said that you could use the free-wheel diode in the IGBT, but that you would have a lower PWM frequency. Maybe 10kHZ or even a little less.


----------



## wakinyantanka (Apr 8, 2008)

MPaulHolmes said:


> This topic came up on the EV Tech list, and according to Lee Hart (one of their top 2 or 3 experts, right up there with the Zilla guy), the answer to that question is "YES". He also said that you could use the free-wheel diode in the IGBT, but that you would have a lower PWM frequency. Maybe 10kHZ or even a little less.


EV Tech list?????
Where is that?
When and how did you talk to the "zilla" guy?
I would like very much to see your programming for the atmega as I'm using the same microchip.
Thanks


----------



## MPaulHolmes (Feb 23, 2008)

wakinyantanka said:


> EV Tech list?????
> Where is that?
> When and how did you talk to the "zilla" guy?
> I would like very much to see your programming for the atmega as I'm using the same microchip.
> Thanks


You can get some information about the EV Tech list by going to evtech.org.
To subscribe to evtech, simply write a message to: 
[email protected].

The Zilla guy, Otmar obenhoensh or something like that, (he has a weird name, but don't tell him I said that!) is on the EV Tech list. Every now and then he responds to questions or comments on the list. It's a VERY knowledgeable group. It's a little intimidating. Most have been engineers for many years. They can be a bit of a wet blanket at times if you have an idea that may not work, but it is still a very good resource.

I'll email you the code I have so far. I tried pasting it, and it kept doing smiles and stuff when I didn't want it to! Feel free to ask any questions about it. Programming a controller is sort of a mess. No question is dumb.


----------



## MPaulHolmes (Feb 23, 2008)

Wait a minute! You can attach files. Ya. I'll do that. Here you go:
OK, this is really stupid! it won't let me attach a file "xxxxxx.c" it has to be 
"xxxxxx.txt" or some other approved .???. Ah! OK, I'm going to change that to a TXT file, so make sure you change it back to .c


----------



## wakinyantanka (Apr 8, 2008)

MPaulHolmes said:


> Wait a minute! You can attach files. Ya. I'll do that. Here you go:
> OK, this is really stupid! it won't let me attach a file "xxxxxx.c" it has to be
> "xxxxxx.txt" or some other approved .???. Ah! OK, I'm going to change that to a TXT file, so make sure you change it back to .c


Will the compiler change that back to c?


----------



## MPaulHolmes (Feb 23, 2008)

wakinyantanka said:


> Will the compiler change that back to c?


I'm using AVR Studio 4 and ATMega16 by the way. Yep, you can just rename it to XXXXX.C from XXXXX.TXT inside AVR Studio 4. Just go up to SAVE AS under FILE menu, and save it there.


----------



## zacknolden (May 2, 2008)

Having a controller over temperature foldback/shutdown, interlock ladder inputs would be cooler for a Home-made controller.
_______________________________________________
Hit the Road with Autopartswarehouse


----------



## ngrimm (Oct 19, 2007)

MPaulHolmes said:


> Wait a minute! You can attach files. Ya. I'll do that. Here you go:
> OK, this is really stupid! it won't let me attach a file "xxxxxx.c" it has to be
> "xxxxxx.txt" or some other approved .???. Ah! OK, I'm going to change that to a TXT file, so make sure you change it back to .c


Thank you for sharing the file. This is the first time I've seen what any kind of controller code would look like for this application. I noticed you are using an ATMega16 and Dan Fredrickson is using ATMega8. Do you think the code will be similar if not interchangeable between the two? Thanks again. Norm


----------



## Dan Frederiksen (Jul 26, 2007)

I did a first simple test today: 
http://www.diyelectriccar.com/forums/showthread.php/first-baby-step-test-my-controller-13014.html


----------



## wakinyantanka (Apr 8, 2008)

I think we are on the right path. Found this pic. of a homemade controller. This fellow now works for Tesla Motors and unfortunately did not make any schematics.


----------



## Dan Frederiksen (Jul 26, 2007)

yep. J.B. Straubel. I asked him for schematics once but he probably never intended it to be open source.
he went the large component way which I intended at first too but it seems much more elegant with smaller parts. and much much cheaper unless it's based on surplus


----------



## xrotaryguy (Jul 26, 2007)

Sorry I haven't been watching this thread for a while. I have decided not to use a DC motor and have been working on a 3-phase motor controller design instead. I'll try to reply to some of the comments that I should have been watching though.



tehsgc said:


> theboy said:
> 
> 
> > What is the square thing with the hacth marks on it wrapped aboutd the high voltage wire?
> ...


Thesgc is exactly right. Sorry, I should have labeled that. Oops.  The square thing is indeed a hall effect sensor. Actually, I don't think that it necessarily works as a hall effect sensor, but it does work as a current sensor. Don't ask me how it does that  




thesgc said:


> What gauge wire are you using to connect the IGBT to the connectors on the casing? I am thinking about 8 gauge, but I am unsure. It's a very short distance, so it doesn't have to be huge I think.


Actually, I think that the wire needs to be quite large dosn't it? I mean, the motor may draw as much as 600A while accelerating from a stop. If the wire is as small as 8 gauge, it is likely to catch on fire in a big hurry. I was considering using 0 (zero) gauge or 1 gauge or 2 gauge wire on the entire high voltage circuit. 

Another reason not to use a small gauge gauge wire is that it gets hot when a high current is being passed through it. Even if the wire doesn't get hot enough to damage the insulation, or catch it on fire, or even if there is not insulation on the conductor, making excessive heat is simply throwing energy away. Given the fact that most of us can not afford $30k worth of Li ion batteries, energy is at a premium. Using heavy gauge wires is imperative.

This is another one of the reasons that I decided to go with AC. Many AC motors are designed to be run at 230V rms or 460V rms. This translates to 325V peak and 650V peak respectively. In other words, the battery pack would need to be either 325 or 650 volts. So, if a 144V DC system pulls 600A while accelerating from a stop, the power delivery under those conditions is 86400W. To get 86400W with a 460V rms 3-phase system, you would only need to pull 187.8 amps. 

This should be a much more efficient way to move an EV. The current is lower, so the wires don't need to be as big and thus the car is lighter. Also, the motor isn't subject to such high current either, so it doesn't get so hot upon acceleration which means less energy is lost in the motor. This also means that less energy is required because less cooling is required (no external fan perhaps). AC motors don't have brushes either, so they have less mechanical resistance within them... oh, and because there are no brushes, they are lower maintenance than brushed DC motors. AC motors tend to be smaller, and more importantly lighter than DC motors too, so the car can be lighter for that reason too which makes the car more efficient again.



thesgc said:


> How does one decide on the freewheel diode on the motor? I found that all that it needs is an Idiode pulse of your motor AMPs.


I have been told (by Dan Fredricson) that the freewheel diode needs to be rated for the same current as the transistor (IGBT or MOSFETs). This makes sense because the diode could potentially be conducting the same amount of current as the transistor.



madmac said:


> C1 will need to be a low ESR cap. A 100nF to 1mfd ceramic cap in parallel would also be a good idea.


Ok, a low ESR capacitor can be one that has a high capacitance rating right? I don't really understand why the capacitor needs to have high capacitance (scary, I know  ), but I will take your word for it. I really need to review the capacitors section in my physics book. 

I don't understand why I would want a second capacitor in parallel. Would both of the capacitors have the same capacitance? Or is one supposed to have a higher capacitance rating than the other?


----------



## Dennis (Feb 25, 2008)

> I don't understand why I would want a second capacitor in parallel. Would both of the capacitors have the same capacitance? Or is one supposed to have a higher capacitance rating than the other?


Paralleling multiple capacitors reduces the overall ESR, which results in longer life of the capacitors and is cheaper as well than buying a large size capacitor.


----------



## xrotaryguy (Jul 26, 2007)

Dennis said:


> Paralleling multiple capacitors reduces the overall ESR, which results in longer life of the capacitors and is cheaper as well than buying a large size capacitor.


Ok, so two capacitors of equal capacitance then. I guess the don't absolutely need to be equal, but then they don't need to be of different capacitances either, so I would just make them equal.

Thanks Dennis


----------



## TheSGC (Nov 15, 2007)

I have changed from 8 gauge wire to copper buss bars and then I plan on connecting 3/0 gauge wire from the controller to the motor and batteries. I have been given 6 feet of the 3/0 gauge, and its freaking huge, and I might be getting 35 feet more for free.

Now I am learning to program my PIC18F2331 and MPLAB is out of my league for the time, so I am using a BASIC compilier that will make the HEX files and allow me to download them to the PIC. It's simple, but for the time simple is all I want.


----------



## ga2500ev (Apr 20, 2008)

TheSGC said:


> I have changed from 8 gauge wire to copper buss bars and then I plan on connecting 3/0 gauge wire from the controller to the motor and batteries. I have been given 6 feet of the 3/0 gauge, and its freaking huge, and I might be getting 35 feet more for free.
> 
> Now I am learning to program my PIC18F2331 and MPLAB is out of my league for the time, so I am using a BASIC compilier that will make the HEX files and allow me to download them to the PIC. It's simple, but for the time simple is all I want.


Piece of advice from a long time PIC developer: don't write in assembly unless you absolutely have to. Writing in BASIC (or another high level language) will speed your development and simplify your debugging. Only jump to assembly if and only if you have a speed sensitive piece of code that cannot be handled in your high level language.

Developing in FORTH is one of my summer projects.

ga2500ev


----------



## Madmac (Mar 14, 2008)

The two caps on the drive serve different functions. A low ESR electrolytic will supply the initial surge when the driver changes state to overcome the inductance in the connections from the power supply. The low value ceramic is used to suppress interference on the power rails that may cause the drive to glitch its outputs.


Dan
"he went the large component way which I intended at first too but it seems much more elegant with smaller parts. and much much cheaper"


It may seem more elegant but is a pain in the b*tt to design correctly. If you look at the device data sheets for the spread of turn on times. The first to turn on will take all the current. The die will get hot spots and fail after a time, maybe 10 hours, maybe 100 hours. If you are unlucky it will fail while you are in traffic to full on.....
There are many tricks to get turn on times under control from selecting devices to slowing turn on times down. The cost of getting legal advice after you have run into the back of someone will be much more than a single device. 

Madmac


----------



## xrotaryguy (Jul 26, 2007)

Greenflight said:


> Here's a link to a guy that built a golf cart controller with an Atmega. Looks like his circuit is a lot like Dan's. He has the C code and everything on there. Might be useful.
> 
> http://www.zeva.com.au/speedy/


I've been looking at building a DC controller again. I looked at the controller on the ZEVA site but am having trouble understanding one of the circuits. Specifically, the schematic has an adjustable resistor, but I don't know why. Also, the adjustable resistor has 3 wires sticking out of it. Why is that? The adjustable resistor is circled in red.


----------



## Madmac (Mar 14, 2008)

A variable resistor or preset has two connections that are the resistor and the third to tap off at any point. This allows the same part to act as a resistive divider and by connecting the slider to one end to act as just a variable resistor.

The circuit has a major design error. A zener diode will conduct when its voltage is exceeded. It needs the current to be limited as the internal resistance is low. In the design above when the preset is at the top end the zener will short out the 24 volt rail, once the zener has gone pop the processor will probably go the same way.

I guess the use is to monitor the battery rail and cut off so as not to over discharge.

Madmac


----------



## ga2500ev (Apr 20, 2008)

Does anyone have a status report?

I'm busy researching my own controller because I believe it's going to be critical for doing a cost effective conversion.

One useful page I'm come across is the EVDL Gems Wiki page for motor controllers:

http://wiki.saymoo.org/EvdlGems/CategoryMotorControllers?highlight=(EvdlGems\/CategoryEvdlGems)

Lots of tips and rules of thumb.

My current thought is trying to parallel IGBTs. I realize the issue of thermal runaway because uneven current distribution causes the hot one to current overload. But when you can find deals like this current Ebay special:

http://tinyurl.com/4mkswqIt's kind of hard to resist. For $110 you can parallel 5 600Vx300A units with a 3x or 4x derating if you limit current to 400A total.

Just looking for ideas and magic smoke stories as you continue development.

ga2500ev


----------



## xrotaryguy (Jul 26, 2007)

I decided to get a little soldering practice before I start the assembly of some semi-complicated components. Fry's Electronics sells a DC motor speed controller for $29.99, which is a good price and it very applicable to what I am doing, so I bought one. Here is a vid of the results.


----------



## TheSGC (Nov 15, 2007)

My status report:

My controller is functional and seems to work just fine with my motor and the 12 volt deep cycle. I will leaving for vacation this week and when I get back I will be getting 3 or more batteries and will do a higher voltage test with my motor. 

I just did a 66 volt test using DeWalt batteries and will post the link to the video. It went well.


----------



## TheSGC (Nov 15, 2007)

Whoa... Double Post..


----------



## gerd1022 (Jun 9, 2008)

I had a successful test of my prototype controller using a similiar setup to dan fred.'s... I havent gotten the pwm chip yet so i used my friends signal generator... 

That thing is very nice... I half want to just use that as my controller (not really). Frequency adjustment on the fly anyone?


----------



## ww321q (Mar 28, 2008)

I got a couple IGBTs to hopefully build a controller , but I know nothing about designing a circuit . I envy you guys with more then two brain cells like me . J.W.


----------



## TheSGC (Nov 15, 2007)

ww321q said:


> I got a couple IGBTs to hopefully build a controller , but I know nothing about designing a circuit . I envy you guys with more then two brain cells like me . J.W.


My design is so simple its hilarious. 2 KHz 555 timer based, 500 AMP limited and 24 to 156 volts using an IGBT. I am hesitant to post my design since I have not done an actual in car testing and it's a one of a kind design.

I too only have two brain cells. One is for engineering and the other is for SciFi....


----------



## ww321q (Mar 28, 2008)

I found a guy on Youtube "AudiMouse" that is working on his own controller to . He wouldn't tell me anything . I guess he thinks if I built it and it blew up I would sue . Oh well ! J.W.


----------



## TheSGC (Nov 15, 2007)

Ok Testing Progress-

The controller works perfectly fine using 12 volts on my traction motor, the ADC K99-4007, and also seems to work just as well at 66 volts with a weed whacker motor since the DeWalt batteries probably can't handle the amp draw and I won't dare jam more than 12 volts on my traction motor unless it's attached to a mass.

Here is a link to the video on my site using 66 volts: http://civicity.blogspot.com/2008/07/back-from-vaca.html

Here is a link to the 12 volt video. The controller looks different between the videos because the 12 volt one was taken a few months ago and I have since changed the outer casing and went from a water cooling system to a fin heatsink, with a few other enchancements.
http://civicity.blogspot.com/2008/03/controller-video.html


Now my controller is not programmable and is all discrete components. The reason behind this is for a while I was having trouble with the PIC programming so I decided on discrete to get started. Well, over the past few weeks I have been working with the PICs again and it turns out the A/D converters are too slow for effective current limiting.


----------



## Doc (Jul 5, 2008)

Just a few tips for you guys building your own controllers.

www.mcselec.com have a very nice Atmel basic pgr called Bascom, free for up to 4k of code. It makes it very easy to use AD's, PWM and LCD's. 
This is my latest hoby project http://denoizer.office-on-the.net it has 6 pwm outputs from a atmega 168
Also check out the IRFP90 power mosfet 200V 96A, digikey sells it for about $6
And if you are building your own charger, Texas Instruments UC2906 and the App notes U-104 and U-166


----------



## Vwbeamer (Jun 16, 2008)

Whay can't you just run a another throttle pot in series with the main throttle pot and use it to set the idle?

Why do you even need an idle? The torque converter should build pressure quick enough to make the car drivable.


----------



## TheSGC (Nov 15, 2007)

Vwbeamer said:


> Whay can't you just run a another throttle pot in series with the main throttle pot and use it to set the idle?
> 
> Why do you even need an idle? The torque converter should build pressure quick enough to make the car drivable.


Here's the easy explanation: The second the torque converter stops spinning, my transmission will disengange and WILL NOT engange until it is place back into Park and then spun up again. The car cannot be spun up in Drive, so idling is a must.


----------



## theboy16 (Feb 28, 2008)

so, at some point this thread took off and flew right above my head, which i'm sure has happend to almost everyone here, except the very few bright lights that shine hope onto all of us who don't want to spend 4000$ on a controller.

how are things coming along? has anyone managed a successful prototype?


Steph


----------



## TheSGC (Nov 15, 2007)

theboy16 said:


> so, at some point this thread took off and flew right above my head, which i'm sure has happend to almost everyone here, except the very few bright lights that shine hope onto all of us who don't want to spend 4000$ on a controller.
> 
> how are things coming along? has anyone managed a successful prototype?
> 
> ...


 
I do have a prototype that has passed all the bench tests sucessfully and is waiting for my EV to be done. (Waiting on coupling- any day now)

I am now working on a more improved controller, that has about $200 worth of parts and when I am done, it will also have an LCD screen to show the status of the controller and the current draw. I am using a PIC microcontroller and the only thing I have left to do is figure out how to use my serial LCD screen.


----------



## xrotaryguy (Jul 26, 2007)

TheSGC said:


> I do have a prototype that has passed all the bench tests sucessfully and is waiting for my EV to be done. (Waiting on coupling- any day now)
> 
> I am now working on a more improved controller, that has about $200 worth of parts and when I am done, it will also have an LCD screen to show the status of the controller and the current draw. I am using a PIC microcontroller and the only thing I have left to do is figure out how to use my serial LCD screen.


I am also building a DC controller, but I'm only doing it so that I can get my feet wet. I'll be building an AC controller because AC is cheaper if you can build the controller yourself. "If" is the most important word in that statement


----------



## theboy16 (Feb 28, 2008)

TheSGC - awsome on your controller. have you posted schematics and pictures anywhere, and what kind of voltage/current can it handle?

xrotaryguy - i'm looking forward to your AC controller, i'm a fan of regen, and surplus motors that are abundant in this mining town where i live


keep up the good work guys!!!

Steph


----------



## Doc (Jul 5, 2008)

I'm building one as well.
a 600A DC controller for 120V with eco mode 
It will have current, temp and rpm sensors/indicators and cruise control and some other features I'm fiddleing with. I use an Atmel MCU and will probably build in a PC USB or WiFi interface for reprogramming and settings. In eco mode it will ramp up throtle and have a lower current limit.
As soon as I have more accurate drawings, I will put on a web site.

I have a problem finding a source for a current shunt I need, maybe someone could help me? I need a MLB-600-50 from Empro, 
http://www.emproshunts.com/webstore/item.aspx?sku=MLB-600-50
I've got a quote from them for $28 but they have a minimum order of $75 and $50 in s&h  Anyone on this forum knows if I could get it somewhere else?


----------



## morvolts (Jun 19, 2008)

TheSGC said:


> Here's the easy explanation: The second the torque converter stops spinning, my transmission will disengange and WILL NOT engange until it is place back into Park and then spun up again. The car cannot be spun up in Drive, so idling is a must.


Please give the specific model # of the trans you are experimenting with. Ive never heard of anything that bizzare and cant see a valid engineering reason for that feature.Im guessing you mean that the engine wont start in gear and that is a safety feature of the Park/Neutral safety switch along with the brake release for the shifter to be moved from Park position.If this is the case it should start in the N position.An electric motor wont have any problem pumping the fluid again once its stopped.


----------



## gerd1022 (Jun 9, 2008)

doc-

I'm using a Tamura model current sensor for my controller. I havent hooked it up yet, but all you do is feed it 5 volts, and it returns 0-5 volts linearly corresponding to 0-MAX amps (im using the 600 amp model)

all you do is run the current carrying wire through the little window.

they are 17 bucks for the 600 amp version on digikey, no minimum order and about 5 buck shipping...

dont know if it would work for your application.


----------



## TheSGC (Nov 15, 2007)

gerd1022 said:


> doc-
> 
> I'm using a Tamura model current sensor for my controller. I havent hooked it up yet, but all you do is feed it 5 volts, and it returns 0-5 volts linearly corresponding to 0-MAX amps (im using the 600 amp model)
> 
> ...


I am looking at those now, and they seem to be ideal for current detection. They keep the logic system isolated from the traction pack, which is the greatest concern. I am in the process of wiriting the code for my status LCD, and once that is done I will be placing everything together, and this current sensor looks like it will be a breeze to use since it's a 0-5 volt system to start with.


----------



## Doc (Jul 5, 2008)

Thanks for the tip on those Gerd102.
I've ordered one and will try it.
Keep in mind though, it's a AC/DC +-600A sensor with a 2.5V offset and it doesn't swing to rail, so for 0-600A it will output 2.5-4V, maxing out at 900A at 4.8V

/Doc


----------



## TheSGC (Nov 15, 2007)

Doc said:


> Thanks for the tip on those Gerd102.
> I've ordered one and will try it.
> Keep in mind though, it's a AC/DC +-600A sensor with a 2.5V offset and it doesn't swing to rail, so for 0-600A it will output 2.5-4V, maxing out at 900A at 4.8V
> 
> /Doc


I noticed that too, but it shouldn't be a problem since all you have to adjust is your software.


----------



## Doc (Jul 5, 2008)

TheSGC said:


> I noticed that too, but it shouldn't be a problem since all you have to adjust is your software.


True, depends on what resolution you need. I'll put a OP after mine to get the full 0-5V swing


----------



## TheSGC (Nov 15, 2007)

Wow, I just hit a snag in my controller design. With PIC processors, the PWM should be 1/500 of the clock speed for the best operation, which is fine when running at the internal speed of 8 MHz. Perfect, actually, since that lands on 16 KHz. But here is my little snag. My LCD display is serial, and operates at a baud rate of 38400 kbps, which an 8 MHz PIC cannot do. 

So now my controller is a two part system. One PIC will control the motor and current limit (Running at 8 MHz) and the other PIC will control the LCD display and the user interface for the controller (Running at 40 MHz).

This controller is getting more and more impressive as I go on. Although, I decided not to implement the AMP usage yet because I am making this idiot proof, and fast moving numbers seem to scare people. All I want the screen to show at this time is the Sofware Version, Mode and Over Current/Over Temp.


----------



## Qer (May 7, 2008)

TheSGC said:


> Wow, I just hit a snag in my controller design. With PIC processors, the PWM should be 1/500 of the clock speed for the best operation, which is fine when running at the internal speed of 8 MHz. Perfect, actually, since that lands on 16 KHz. But here is my little snag. My LCD display is serial, and operates at a baud rate of 38400 kbps, which an 8 MHz PIC cannot do.


Hm? Why not? Can't you divide the clock with 208 and be happy with the mere 0.2% error?


----------



## TheSGC (Nov 15, 2007)

Qer said:


> Hm? Why not? Can't you divide the clock with 208 and be happy with the mere 0.2% error?


I can't do that because there are set equations for the baud generator.
[8,000,000Hz/38400Kbps]/64 -1 = 2.25
8,000,000Hz/[64(2+1)] = 41,666 kbps

8.5% error really sucks. According to the datasheet, 8MHz clock is only good up to a 9600 kbps baud rate, anything higher and you need an external clock. 

[40,000,000Hz/38400kbps]/64-1 = 15.27
40,000,000Hz/[64(15+1)] = 39062.5 kbps
A mere 1.7% error, which seems to work just fine for the LCD.


----------



## Qer (May 7, 2008)

TheSGC said:


> I can't do that because there are set equations for the baud generator.
> [8,000,000Hz/38400Kbps]/64 -1 = 2.25
> 8,000,000Hz/[64(2+1)] = 41,666 kbps
> 
> ...


Hm. Fixed 64-divider. That's a tad sucky, yes. I guess switching to AVR isn't an option? Otherwise they can do up to 115.2 kb reasonably well (-3.5%) and 38.4 kb very well (0.2%) at 8 MHz.


----------



## Wragie (Jul 26, 2008)

One comment is the lower the baud rate the more you can get away with. I would look at the display and see how low a baud rate you can use. This will vary with the model and what you are displaying. Most serial types work quite well at 2400/4800/9600, everything over that wastes cycles. The lower the speed the greater the baud error is tolerated. 

You could also just shoot just the data to a second pic that only deals with the display. Then use it to capture the data and integrate the data into the desired format and then sustain the display.


----------



## TheSGC (Nov 15, 2007)

Wragie said:


> One comment is the lower the baud rate the more you can get away with. I would look at the display and see how low a baud rate you can use. This will vary with the model and what you are displaying. Most serial types work quite well at 2400/4800/9600, everything over that wastes cycles. The lower the speed the greater the baud error is tolerated.
> 
> You could also just shoot just the data to a second pic that only deals with the display. Then use it to capture the data and integrate the data into the desired format and then sustain the display.


I am just going to shoot the data to another pic. The LCD I have only works at 38400.


----------



## OHM (Jun 30, 2008)

Is it possible for a controller designer could take a leaf out of auto
manufacturers like toyota and split the main ¨brains¨ from the rest
rest of the IGBTs and anything that gets hot?

This way maybe a cheap Delco automotive ecu could be used
and have more control over any kind of malfunction or heat?

If so this also could be an easier method to convert an ICE car to an EV.
You could use most of the guages and control systems already part of 
the vehicle etc.


----------



## TheSGC (Nov 15, 2007)

OHM said:


> Is it possible for a controller designer could take a leaf out of auto
> manufacturers like toyota and split the main ¨brains¨ from the rest
> rest of the IGBTs and anything that gets hot?
> 
> ...


Most of the dash systems still work with an EV. As for the "brains" being separated from the IGBTs, the reason why they aren't is because of the short wiring they require to keep induction low and to prevent any sray EM from influencing the control. 

Also an automative ECU does not have anything that can even remotely control a series wound motor, like PWM, A/D conversions, throttle input, current sense and limit so they would be pretty useless.


----------



## TheSGC (Nov 15, 2007)

I have an update on this controller-

Since I have been bogged down with school work, I had to suck it up and order a controller just to get the EV going. This gives me plenty more time to find the proper materials to make the controller (casing, heatsinks and dc-dc converters) and to add some other features.

Here are the list of features I have now:
-24-156 Volts 
-Up to 500 AMP programmable current limiting
-Over Temperature Slowdown/Shutdown
-Programmable IDLE control
-0-5K Throttle Input

Now here is the list of features I am working on:
-LCD Status Display
-Battery Pack monitor
-IntelliDrive

Now the IntelliDrive is something I have been working on paper for quite some time. The idea behind IntellDrive is that controller would be optimzed for each motor (programmably) so minimize motor damage and bring the best performance. You would put in the max amps and the contunuous amps and the 1 hour/30 minute/15 minute/5 minute amps. It will also be able to estimate the range of what left in your pack, record driving trips, and let you set a desired range and the controller will limit the battery current to a level it thinks will give you that range. (You would have to program in the pack voltage, battery type and AH ratings)


----------

