# Extended Chevrolet Express van converted



## Nathan219 (May 18, 2010)

Let me be the first to welcome you, There are some very intelligent people here, and you are not a noob you have a working electric vehicle.


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## madderscience (Jun 28, 2008)

+3 for hacking skills on the inverter 

a 10.8 kwh nominal battery (12 * 18 * 50 / 1000) is going to be on the small side for such a large vehicle, which likely explains the wide voltage swings under load and while regenerating. The quality of the batteries would make a difference as well, e.g. if they are cheap UPS or emergency lighting gels they won't handle the amps or cycling nearly as well as if perhaps they are a better brand like hawkers (what was used in white zombie before it was upgraded to lithium I believe) or maybe something designed for wheelchair service.

One thing you could try that might not break the bank to get a bit more torque at the expense of top speed would be to change your rear end gear ratio. If the van was an automatic chances are pretty good it is a 3.23 or 3.54 gear ratio. You could go to 3.77, 4.1, or several other standard ratios.

I'm looking at a direct drive conversion in a scion Xb (a mini-mini van basically) with a solectria AC55 system (80kw peak power). The whole thing should come in under 3000lbs hopefully and I am looking at probably a 4.77 or 5.3 gear ratio. Basically, whatever the highest ratio I can find for a divorced toyota differential to replace the engine and transaxle.

Cheers


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## subcooledheatpump (Mar 5, 2012)

Yeah the batteries are UPS batteries, not ideal. 

I got some nice big hawkers (42 Ah) for cheap, about 30 of them, but couldn't get anymore. Since it was to be a 500 volt+ conversion, I had to get some other smaller batteries. Someday I do hope to get some better batteries. I think the temperature also affects their current abilities. Where I live it's cold this time of year, and they seem to do a little better when they are warmed up though I choose to keep them cold in an effort to prevent sulfation.

The rear end in the van is 3.73, the biggest I can get without a transmission is a 4.1 though I'm not sure of the difficulty in changing gears, I've never even changed a pinion. Any input on that subject would be appreciated.

The motor seems to be okay at 1*F which is 60 Hz. The calculation I did tells me that for every 2 Hz, the van moves 1 MPH so 60 Hz gives me 30 MPH. So it struggles a bit going faster than 30 MPH. Depending on their condition the batteries drop to 460 volts attempting to go 60 Hz on some grades.

Thanks for the feedback


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## Bowser330 (Jun 15, 2008)

+1000 for DIY AC Inverters, really cool conversion. 

The extra low end torque of a DC setup might have suited your vehicle better, is there a reason you went AC > DC?


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## subcooledheatpump (Mar 5, 2012)

Many reasons for going AC. 

1. I am no expert in power electronics, but I wanted to make/modify an inverter. A simple DC controller would have been too easy for me to make. I felt like I could do better than that.

2. Stall torque. An AC motor with proper cooling can output continious peak torque even when stalled, not easy with a DC motor when the commutator and/or brushes can burn from being stalled. This feature is necessary with a vehicle this size, especially on hills. At a local industrial shop, the manager told me of a story where that very thing happend, right in front of the shop by a college professor driving an EV with a DC motor.

3. Regenerative braking, also necessary, with a vehicle this size, you'd be crazy not to. For this van to have any usable range it must have regenerative braking and it must be controllable. The van also eats brakes like they are a snack. They are not cheap. Regenerative braking saves alot of money. 

4. AC motors are an industrial standard. Go to just about any industrial surplus store and they have tons of AC motors to choose from. The motor I got for the van came from a surplus store up near the great lake in Ohio. It was very well priced and the size and weight were good for what I needed. DC motors, especially for EVs are a speciality; IE not in my price range.

5. AC motors are in the biggest and baddest EVs; Trains, Mining trucks, Excavators, Shuttle cars, and of course Teslas. There must be an attraction. They do use a bit less energy for the same output and they are smaller and lighter. 

One of the reasons I posted my conversion; to show AC can be easy and affordable. It seems people in the EV community are afraid of AC motors because of the complexity/cost of the controller/ inverter. Really it's not that bad. With a little knowledge and some scrap parts from a surplus store, anyone could make a usable AC controller. Of course anyone can feel free to ask me anything about the modification, I'd be glad to help.


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## Mark C (Jun 25, 2010)

I'm impressed with the DIY industrial motor controller and how you've made it work. I'm also curious about your battery situation. I am assuming {I know that can be a bad thing} that what you have is a temporary solution to test the waters as they intrude on precious load floor space. What's the longer term plan call for? Relocating them under the floor maybe, going lithium, .......


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## subcooledheatpump (Mar 5, 2012)

Yes the original plan was under the floor for the batteries, and for the batteries that run the hydraulic pump and the heater (and future A/C), under the hood. I put them in the back just to test their performance in the van before I make any permanent arrangements

I'm still a noob in many ways when it comes to this, but I'm slowly learning about how my plans will work out in the real world vs. what I have pictured in my head. 

The batteries will have to be better, especially to keep up with my plans of getting a bigger AC motor and more range + more speed. I'd like to bring the van back up to it's original power; 300 HP and still get 100 miles range. Not an easy task I realize but I'll try to do it anyway. 

The modified controller at the present time can output more power but the motor I have won't accept it. I switched to 200 amp current sensors and the motor only saturates. (hums but doesn't output more torque)

So this summer I'll be looking at getting a better motor.


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## Bowser330 (Jun 15, 2008)

Hey Subcooled,

Would you be willing to support more builds with converted VFD's Inverters? 

What I mean is, there have been some guys converting VFD's but they aren't very open with the design or clear with the steps to help others...now I understand it's their hardwork and no doubt they are deserve the enjoyment, but helping the community is also important.

You obviously know your way around a VFD and I wouldn't be surprised if you could build the VFD into an even more powerful inverter, say to match a more powerful AC motor...

I am sure a lot of people would like to know how hard (and expensive) it really is to convert a VFD into an inverter for a powerful Remy motor, for example...
http://vaxosystems.com/store/products/104-hvh250-090po-pm-g1-remy-electric-motor.aspx

Parallel Wound
Oil Cooled
Permanent Magnet
Generation 1 Housing
Rated Voltage – *320 VDC Bus*
Peak Power – 150 kW
Continuous Power – 90 kW
Peak Torque – 320 NM
Continuous Torque – 165 NM
Base Speed – 4600 RPM
Maximum Current – *600 Arms*
Weight – 50 kg


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## subcooledheatpump (Mar 5, 2012)

Yeah I'd be willing to help just about anyone with a modified VFD project. 

Modifying a VFD is really pretty straightforward, matching old parts to new parts. 

It gets tricky in higher power levels though. The problem is, larger IGBTs take more gate current to turn on quickly. So most of the time a modified VFD is limited to the existing gate drivers. The gate drivers of course can be replaced but there is a limit. The onboard power supplies on the VFDs can only source so much current; chances are they can only supply a few miliamps. So adding gate drivers and larger power supply capacitors can help increase the limit but it only goes so far. 


Thats one of the reasons I went for a higher voltage system, reduced IGBT current thus reduced gate drive current. 

Lower switching frequency also helps

For the motor in question from Vaxo systems, that would require 600V 600A IGBT modules. In theory it can be done from even a small VFD, but in order to counteract the need for larger gate drivers and spare the IGBTs from destruction, the switching frequency would need to be lowered to say 1 to 2 kHz. At that point you would then have a very loud EV. The noise doesn't really bother me but I know some don't like it. 

The other problem; IGBTs of that size are expensive. Not too many are up for the idea of playing with $1K+ of IGBTs and capacitors in an experiment that could blow up and then be worth nothing. There are always surplus stores, where I got all of my power electronics though. 

All in all though I'd be willing to help anyone, like I said in my previous posts; it's not that hard to make a good inverter for an AC motor. 75 kW or so is pretty easy. 100 kW+ is where it gets hard. I'm personally still trying to push the system in my van even further. I'm limited by my current motor and batteries though. 

Any specific questions about VFDs I'd be glad to answer


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## Bowser330 (Jun 15, 2008)

thank you for being a resource


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## subcooledheatpump (Mar 5, 2012)

Link to a little page I made, contains more information about converting a VFD like my own

http://www.dhcservice.com/EVExpress/VFDmod.htm


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## subcooledheatpump (Mar 5, 2012)

Got A new motor for the van, 30 HP 4 poles. I had a piece of cold rolled steel machined one side for the yoke (1.5") and the other side for the motor shaft (1.875") But oops! turns out the motor shaft is actually 1.625" no problem, a sleeve bearing is on the way later today and the motor will be lifted into the van. More updates coming soon


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## JRoque (Mar 9, 2010)

Hello Sub,

I had missed your VFD mod page before - excellent write up! Have you considered the need for snubbers now that the IGBTs are replaced and handling higher power?

Does the new motor have an encoder so you can run in vector mode?

I did some testing with a Hitachi VFD and it looked promising. The one thing I couldn't do was proper (in my view) regen using an external input other than deceleration. In other words, I wanted to apply a signal that corresponded to the amount of regen I wanted. 

I believe coasting, and only applying regen when wanting to slow down further, is the way to go. If I recall correctly, the problem was that as soon as I decelerated the drive would either regen to a stop or let the drive spin down freely. The latter was what I wanted but the problem was that in that mode, the drive lost it's sensorless voltage and could not measure RPM anymore. That resulted in no feedback as to what the motor was doing.

Perhaps adding a shaft encoder would have worked as RPM reporting is likely to continue without sensorless dependencies. But after that test, I left it there as so many other parameters and functions were still missing from an industrial VFD when compared to a purpose build controller like the Curtis or Soliton. There's also the packaging, cooling facilities, etc that seemed it would have taken months to make and debug. In hindsight, I would have been done by now!

Good work and very interesting thread. Looking forward to your updates.

JR


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## subcooledheatpump (Mar 5, 2012)

You can't actually see them, but I am using 3 snubbers on my inverter. I've also worked out a good scheme for controlling the motor that mixes hydraulic braking with regen and allows regen on pedal lift as well. 

The trick is using the current limiting feature of the VFD. During normal operation, the VFD software is programmed to limit the current to 150%. When the brake pedal is depressed, the current limit changes to 40% current limit. That way, the van will slow down under regen but with a lower current limit so the regen isn't as strong, but also, the hydraulic brakes can be applied at any time and the motor will continue regeneration. 

Also, the sleeve bearing looks like it's going to work, it's arrived and I'm going to try to fit it into the piece I had machined.


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## JRoque (Mar 9, 2010)

Hi, the guys at EVTV used a hydraulic sensor that puts out 0-5V depending on the brake pressure level. Depending on the sensor, the 5V max can be reached before the brakes have applied too much mechanical pressure hence leave most of the stopping to regen but still engage mech braking for safety. This is the kind of setup I'd like to use.

This stuff is hard to do right, no doubt. Some OEMs still resort to regening on accelerator positioning. I'm sure this works fine and I have been told before on this forum that you get used to it and it works very well so perhaps it's just a nit I should drop.

As for your regen percentage, that could work. Does it matter that the regen percentage is fixed vs varied vehicle speed? ie: will you notice a difference if you apply 40% regen while doing 5 MPH vs the same percentage at 70 MPH? And how much will affect braking expectations when your pack is already fully charged and not able to take that 40% regen current?

One of these days I'll contribute some useful idea instead of just asking a bunch of questions... 

JR


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## GuySmily (May 11, 2012)

I'd actually like to use up some of the dead zone at the top of the pedal before actually engaging the hydraulic brakes. Seems like you can adjust most factory pedals to add a little more "freeplay" / dead zone at the top.


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## subcooledheatpump (Mar 5, 2012)

As for the fixed percentage, it works best mainly at high speeds. Going slow, like 5 MPH, lifting the accelerator pedal stops the van just fine, of course people who aren't used to it step on the brake even going slowly and there is a slight 'thump'. Not a big deal but people are a bit suprised by it. As for the batteries, yes when they are full the regenerative braking doesn't work as well, but of course the hydraulic brakes can always be used. The deadzone in the brake pedal is actually used for the regen on braking, and pushing it down even further activates the hydraulic brakes. I tried to get it as close to a "normal" car as possible but it still has a way to go


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## subcooledheatpump (Mar 5, 2012)

The new motor has been installed. 
This is the mounting system, right angle brackets on all four sides of the tube steel that holds the motor

















this is the motor, I tried to paint it but ran out of black spray paint, I got some more. I'll be working on painting it and the tube steel tomorrow. 

The van does have more torque and power. I took it out driving and it's acceleration is improved, but I'll have to reprogram the controller, it's a little wacky since it was programmed for the 15 Hp motor. 

The solid mounts work good, but there is extra stress on the frame. The old transmission cross member had to be removed to get the motor into place. When I tried to replace it, it had to be hammered into place. Normally it slides right in, so I suspect I have added stress with my solid mounting system. That might be a good thing though. I can also hear the motor and the gears from the differential now. 

I also added a resistors to the output of my current sensors, so they will let more current flow without setting off the drives' over current protection

more updates tomorrow


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## JRoque (Mar 9, 2010)

Hi. Well that was quick.... Good job.

Two points:

1. See if it's possible to brace your motor support directly to the chassis and not through 4 bolts. Even if you weld some brackets that reach the underside it would be much better structurally that handing from bolts like it is now. Adding hard rubber mounts/pads to the motor base could help improve vibration noise.

2. Can you route that cable up and not down from the junction box? Or at least tuck it in over the motor support so it's not exposed to the road like it is now.

JR


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## subcooledheatpump (Mar 5, 2012)

Yeah I could do both of those pretty eaisly. 

thanks for the tips

I'm thinking of doubling up the brackets, one on the inside of each side in addition to the outside. 

I'll be working on that conduit for a while, I've got to get the right adapters for it to actually fit the conduit box. I just tied it up with plastic cable ties for a quick fix since I wanted to take it for a quick drive. 

Speaking of which, I took it for a drive. I hit probably about 50 MPH (going to get a GPS speedo). Definitely more power, torque and speed. Throttle is a little too sensitive so parking can be a bit of a problem. 

I since I now have 4 poles and before I had 6, each increase in frequency means 1.5 times more speed, which makes the throttle potentionmeter 1.5 times more sensitive.

My modified inverter seems to be okay but it hums pretty loud now. Peak current 150 amps. 

overall I'm happy but still, much more works needs to be done


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## subcooledheatpump (Mar 5, 2012)

Well today I've been working out the controller programming. I think I've got it where I like it.

I'm having some issues with the batteries though, I think they may not be able to supply the current I require safely. I can smell a sulfur like smell where the batteries are in the van. I'm thinking I've exceeded their maximum discharge rate. 

I'm thinking of getting more batteries and adding them in series, then leaving them only partially charged to allow more headroom for regenerative braking. Any thoughts?

Also, does anybody know of some decent batteries that don't have a high capacity, but have high current discharge abilities?

I don't want alot of capacity, because I don't want the van to take forever to charge, I won't be driving it long distances anyway. I just need the high current (150, maybe 200 amps) delivered without explosions or gasses building up


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## Nathan219 (May 18, 2010)

The A123 20 ah cells can supply 20C and are available. That is your best bet for a low capacity fully capable system. Example you can extract ~400 amps from the 20 Ah cell for 3 min. 
You could add a string of Lithium in parallel with your pack This would allow the Lithium cells to supply current during acceleration and absorb current during regen because of their low internal resistance. IMO some lithium cells are almost like capacitors with the way they can handle current. 


Good luck,

And keep up the posts I know I am interested in your progress!


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## subcooledheatpump (Mar 5, 2012)

New video, motor and driveshaft turning in the end just cause

Batteries seems to be okay now


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## JRoque (Mar 9, 2010)

Excellent! thanks for the video.

I would charge the batteries full and then, if possible in the VFD, limit the bus voltage max and regen current peak to protect the batteries. I agree with the previous comment on going with A123. Even if you just get enough of them to get to your bus voltage (serially connected), it will help with the high current draws and to soak up the quick rising regen.

I think you will notice a nice difference in low end torque if you install an encoder and run the controller in vector mode.

JR


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## subcooledheatpump (Mar 5, 2012)

Thanks for the advice guys. 

I'll have to work out how to get some of those A123 cells. 


Yeah I do need a FOC/vector drive with a little more intelligence as to what the motor is actually doing. 

The motor controller I have now is sensorless, does a pretty good job of making peak torque happen in the low end, but it's still too confused and the motor can step out sometimes


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## Otmar (Dec 4, 2008)

subcooledheatpump said:


> Yeah I do need a FOC/vector drive with a little more intelligence as to what the motor is actually doing.
> 
> The motor controller I have now is sensorless, does a pretty good job of making peak torque happen in the low end, but it's still too confused and the motor can step out sometimes


First of all, Nice Job! 
I love the idea of leveraging engineering that was done for higher volume applications and applying it to us hobbyists. 

I have a early Honda Insight sitting here converted to electric with a GM EV-1 motor and a Zilla 3 phase power section that really needs a control board. I am not willing at this time to program my own (too many other things to do!) but would like to get the car running and maybe also work toward a open solution to drive my small pile of EV-1 motors so others could make use of them. I am very interested in the idea of using a industrial VFD brain for this if I can get what I want without too much work. 

Electrically I'm fine since the Tri-Zilla has plenty of current capability and gate drives built in, but I'm concerned about choosing the right VFD for the control since I am not familiar with the various options. I'd love some advice on this part. I've spent enough on this project that a few hundred $ is not a problem, so it doesn't have to be the cheapest one on ebay. The motor is essentially a 137hp (wired as if it were a 60V 60hz) 4 pole Y connected unit that wants a ~312V battery and 400hz. It has a quadrature encoder with about 180 PPR IIRC. 



A few concerns that I have that may be non issues, but I'd love advice on them:
1) I see in the Toshiba VF-S11 data sheet that it can do "open loop vector". Does this mean it can't do vector with a speed sensor? I know from other AC drive projects that a speed sensor and a fast control loop is critical for smooth high torque starts. Once the rubber mounts and drive shafts start winding up the motor speed can change very rapidly and start up oscillations. Ideally I'd like a controller that is designed to handle that sort of thing. 
2) The inverter running my milling machine will shut off if the load goes too high, in the EV we want it to just limit to maximum torque. Is this what the S11 calls "constant torque" operation?
3) My intention for this car is to put it in a local car share. Therefore I'll need to include all the usual safeties and it will need to drive like a normal car. Right now if you try to accelerate too fast it shuts down and you have to coast to a stop to restart it, clearly it's too much of a "science project" right now (the current software was a local college senior engineering project). Is there anything about the VFD conversions that would stop it from being a nice turn key operation?

Thanks to all of you doing VFD conversions for blazing the trail and for any advice you can offer!


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## JRoque (Mar 9, 2010)

Hello Otmar, I'll let the OP comment on your questions. 

I bought an SJ300 drive some time ago to make the VFD conversion. I found that it did everything I needed except for proportional regen based on the brake pedal variable input. I suspect it will do that as well if I add a shaft encoder. You need an optional encoder board that's ~$130.

You can certainly limit current going forward or coming back from the motor. You can also fault on high/low bus voltage. You can regen on decel as many others do. The drive has a separate 24VDC logic power supply input so bus voltage can be independent. You can feed it 2 phase power or bypass the diode bridge altogether, though these would be moot once you've replaced the power section. It also supports RS485 and has a number of programmable I/O pins. The drive will adapt to most any motor automatically or you can enter the motor specs manually.

So it will move your car and do basic functions needed for that. If you contrast what's provided with what you get out of a Curtis drive, there's a wide margin for improvement and refinement, of course.

JR


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## subcooledheatpump (Mar 5, 2012)

Hi Otmar, 

Yes the VF-S11 is only Sensorless. 

It does have current and voltage limiting abilities that will prevent the drive from shutting off during any kind of overload, which as you said is essential 

The drive has a feature which it calls "autotuning" which automatically detects the resistance, and inductance of the motor stator and makes a model of what it thinks will be the best V/Hz ratio for the motor. It works in the van but as I said it's not perfect because it isn't always right. It makes an educated guess and it's reasonable, but not ideal.

As JRoque said, what is needed is a variable torque response regenerative braking system, so that when the brake pedal is pressed, the drive will serve negative torque proportional to the pressure on the pedal. 

The acceleration is pretty good though. Sometimes the motor steps out and you can hear the motor hum. If the accelerator is lifted you can feel the acceleration come back and you know that you're in synchronization again. This is due to what I said before, it needs a speed sensor and true vector control, not just sensorless.


At the moment I have a pretty wild and crazy idea, which will probably never work out in the real world, but I'm thinking of trying it none the less, and that is to modify a VFD and try to sell it on ebay, As is with no warranties. Not sure who would be interested but I am seeing more and more people getting interested in Induction motors and high voltage in EVs. So you never know

As far as driving the Tri Zilla, Just about any VFD with true vector control should do the job, and long as the encoder is compatible. I don't have any specific recommendations because there are so many VFDs out there, it's hard to say which one is the best. Most VFDs will autotune, that is automatically set the parameters/programming. So I'd say look for one with autotuning and a compatible input. I'd also check for switching frequency compatibility, just to make sure it will work with what the Tril Zilla gate drivers are expecting. I would say, but I'm actually not sure what the original tri zilla switching frequency was supposed to be. Also the voltage, I'd imagine the tri zilla works from a relatively higher voltage. 240 volt 3 phase VFD will need 340 DC to turn on and run so the Tri Zilla should be compatible with that

Also I'll be happy to answer any more questions you may have about VFDs and induction motors in EVs


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## Otmar (Dec 4, 2008)

subcooledheatpump said:


> At the moment I have a pretty wild and crazy idea, which will probably never work out in the real world, but I'm thinking of trying it none the less, and that is to modify a VFD and try to sell it on ebay, As is with no warranties. Not sure who would be interested but I am seeing more and more people getting interested in Induction motors and high voltage in EVs. So you never know


Doesn't sound too wild to me. Few people have the skills to upgrade a drive and doing several of the same at once could save some money. 

Thanks JR for the SJ300 info. So that one looks like a good possibility for my application with the SG-FB card added. I've been looking through the instruction manual and it looks like most settings can be changed on the fly with the RS-485 serial port. It looks pretty ideal to me. 

I see the SJ300 is obsolete and the SJ700 seems to be the new version of it. I wonder if it's worth the upgrade? http://www.hitachi-america.us/supportingdocs/forbus/inverters/news_releases/hitachi-introduces-sj700-series-ac-drives.pdf

We could use an Arduino to send torque and speed commands for drive and regen and control while reading the accelerator and brake pedals. I like that since it allows us to add any feature that we normally would want such as gradually reducing current as the battery voltage reaches the high or low limits and controlling the precharge and startup. 

Any other suggestions of the best drive to start the project?


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## subcooledheatpump (Mar 5, 2012)

The SJ700 looks pretty good just from what the one line in the PDF says 

"advance trip avoidance functions"

And the surge voltage supression

Plus it claims the sensorless vector can produce peak torque a .3 Hz. Might be work a look, though they are probably pretty expensive. Eventually though, they will show up used at the surplus stores. I'll keep an eye out for one. 

If you are keeping the transmission in your car(s) a drive with torque mode would be really useful I'd think. It could make the car behave essentially as if it still had the gas engine, just no gas. If you could then get a drive with torque mode and speed mode switchable with a small switch in the car, you could use them to switch between "race" and "street" modes. The speed mode would be good in the snow, since you always set the speed and not the torque, therefore you have control of the wheel speed and not the torque. The torque mode would be good for racing or fast acceleration, since you want it to hit maximum speed as fast as possible. Good in the corners too, you don't want regenerative braking on pedal lift when you are taking the corners fast.


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## JRoque (Mar 9, 2010)

Hi. I bought my 5HP SJ300 new on eBay for $300. There's a 1 HP version now, used, for ~$120. Too bad the encoder board is more than the drive itself, but it is also available on eBay.

I fought myself over what to do with the interface. On the one hand, you do get more flexibility by intercepting the pedal signals and massaging before sending to the drive. On the other hand, it might be more reliable to connect the pedals directly to the drive and use the micro to command max current and voltage levels. If the micro were to fail, the drive would still work. It would also reduce the chance of sudden max throttle or brakes if something were to go wrong with the micro. But I also have a counter argument for that so you can see I've gone nowhere with this. 

I did build a prototype to link the pedals to the drive and it worked well with the exception of proportional brake regen as mentioned above - the drive shuts down when you command 'stop' so it loses track of the motor speed. This will probably be cured by adding the encoder. 

The SJ300, and I imagine many more also, can resume motor speed realtime without the need to stop the motor like some old drives did. Hitachi also provides free software for their drives. I did try ProDrive package but never got it to talk to the VFD. IIRC, it had something to do with the drive port I was using and not the RS485 i/f. Allen Bradley, Siemens, ABB and Eurotherm come to mind as good drives also.

JR


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## subcooledheatpump (Mar 5, 2012)

Sad news today 

















While range testing the Express, the controller exploded. 

I suspect it was due to overvoltage. 

I was going down a hill, I had my foot on the brake pedal. At the bottom I let off the brake pedal and the controller exploded. 

To be honest, it needed a better controller anyway. The new controller I want to make will have better IGBTs, it will be liquid cooled and it won't be in the passenger compartment (the explosion was quite violent, I won't have anything like that sitting next to me again) and I want it to have FOC/Vector control 

Stay tuned for the next controller and an overhaul of the van


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## DDDvvv (Apr 2, 2012)

that is terrible news. all 3 phases are gone? at least, the motor did not "run away" ( ac motor advantage.) any new ideas/ plans for the next controller?


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## subcooledheatpump (Mar 5, 2012)

With the new controller, I will use 300 amp 1200 volt IGBTs (or maybe 600 amp 1200 volt), I will also use larger gate resistors to slow the switching to reduce voltage buildup. I'll keep the same switching frequency ( 3 kHz) and they will be liquid cooled

I'm also going to use a dynamic braking resistor to work in all braking situations, that way the voltage won't buildup and go out of control. 

My theory is, the capacitors I used are 350 volts each, so in series that means 700 volts max. When I had my foot on the brake pedal the voltage was 720 volts, usually it goes alot higher though. I suspect when I let off it jumped too high for the capacitors to take.

Which brings me to my next change, I will use the highest voltage capacitors I can get, which are hopefully 450 volts or more. In series I want 900 volts DC, higher than the cut off point of most 500 volt VFDs. (830 volts) 

Also most VFDs it seems activate the brake chopper at 730 volts, so again, probably too much voltage caused my problems. 

The induction motor was definietly a good choice, especially since I had to get it towed with the rear wheels on the ground, meaning the motor had to be turning. Not a problem for the induction motor.


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## subcooledheatpump (Mar 5, 2012)

These are the replacement IGBTs, they are CM300DY-24H

Up next, liquid cooled heatsink/coldplate and 450 volt 6000 microfarad capacitors


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## subcooledheatpump (Mar 5, 2012)

IGBTs are mounted on the liquid cooled heatsink


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## subcooledheatpump (Mar 5, 2012)

I got the new controller (temporarily) in today. 

I tested it, and it works. Some programming to work out, but it works. 

In the upper left of the picture is the water cooling pump. I decided to keep the controller inside the van, and move the batteries out. The controller is now where the accessory batteries used to be. The accessory batteries will be moved to where the engine used to be.


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## DDDvvv (Apr 2, 2012)

now thats one fiiine water cooled heatsink!!!
where/how did you get it done? because i want one..


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## subcooledheatpump (Mar 5, 2012)

The surplus store that I get my power electronics from has them for sale. 

Sadly though, they don't have them up on ebay, you actually have to go in person to get one. 

I knew where they were for a while and one day I decided to get one. Even some of the employees were impressed with it, they didn't know it was there...


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## Nathan219 (May 18, 2010)

You need to tell us where you get your electronics from, because most people I am sure don't have access to a surplus store like the one you are blessed with.


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## subcooledheatpump (Mar 5, 2012)

http://www.ctr-surplus.com/ebayauctions.html


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## NintendoKD (Apr 29, 2012)

cool link, lots of goodies there, I'll need that one for my build.


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## subcooledheatpump (Mar 5, 2012)

Okay small update, I'm getting a controller with torque control, DTC, with speed and torque modes. Freight company is supposed to be picking it up tomorrow. I will update again when I get it. 

The contactors and other controls for the heater, brakes, and steering have all been put into proper electrical enclosures. I also got a vacuum pump to operate the HVAC dampers/air doors. Pictures soon


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## subcooledheatpump (Mar 5, 2012)

I got the new controller
It's an ABB ACS601

















I am a little confused with something though, It seems I can't get full torque with DTC, I can only get full torque in scalar mode with "IR Compensation" which I assume is more or less equal to torque boost or voltage boost. 

The torque control with DTC works great, it just doesn't provide full torque, which is important. Torque control is also important, I just can't seem to make both happen at the same time. 

Any thoughts on this?


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## Tesseract (Sep 27, 2008)

subcooledheatpump said:


> ...I am a little confused with something though, It seems I can't get full torque with DTC...


DTC needs accurate rotor position information to deliver high torque at 0 to very low RPM; are you using an encoder or resolver?


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## subcooledheatpump (Mar 5, 2012)

I'm not using any encoder now. Knowing that I may attempt to attach one. The drive came with (what I assume is) an encoder board. I've got an encoder as well. Now to get it onto the motor.. 

Thanks for the info


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## subcooledheatpump (Mar 5, 2012)

Okay, the van now has yet another motor, a 30 HP 6 pole motor, and things are looking pretty good. 

The controller seems to be able to get up to 3 x nominal torque from the motor. The DTC is great, it drives just like the normal gas version in torque mode, and it can go into speed mode with the flip of a switch for regenerative braking. 

The biggest issue now is the batteries... they just can't output enough current. Youtube kind of ruined the video, but you might be able to see where the bus voltage drops down to aronud 445 volts 

Max power at this point seems to be something like 50 kW when the batteries are charged and heated.

Still, the van seems to be able to do 50 MPH on level roads pretty easy.


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## TEV (Nov 25, 2011)

Congratulation for your drive test. Also a very dramatic end


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## subcooledheatpump (Mar 5, 2012)

Thanks, and yeah that cell phone... it has interrupted so many important life events! It finally got the van too


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## flyn_brian (Oct 21, 2012)

Dude that is awesome. I first ran into your videos on YouTube with your explanation on IGBT's. Could you explain further on your hack on the ABB ACS601 VFD. I am considering converting a Saturn SL1 and I have experience with those particular drives. So there would be no problem for me to program one up to do what I want.


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## subcooledheatpump (Mar 5, 2012)

The ACS601 I didn't really 'hack', not like the VFS-11 anyway. 

I'm using the ACS601 with the torque control macro, and I'm using a toggle switch to switch between Torque and speed control (DI3) 

Speed and torque refrence are both set to AI1, thats my PB6 pedal potentiometer input.

The current limit is set to 160% Ihd and torque limit is set to 300%. 

The batteries just hook right into the DC bus connections. I use 10 Ohm precharge resistors, though I'm not sure if they are even needed, I think the ACS series may have built in precharge resistors. 

Motor control is set to DTC and the output goes right to the 30 HP motor.

Thats really all I've done.

Good luck with your projects, and please post your results!


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## flyn_brian (Oct 21, 2012)

I know this is going to take me a while to do as money is tight right now but at least I have a donor car and I just bought an ABB ACS601 drive on ebay. Batteries seem to be the major hurdle. The drive I bought is only a 5 hp unit so I think it will need to be beefed up with some larger IGBT's along with the proper gate resistors.


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## subcooledheatpump (Mar 5, 2012)

It probably is possible to change the IGBTs, though I'm not really sure how badly that would throw off the DTC operation, since it's reliant on current and voltage sensors. 

It might be proportional, IE bigger current sensors for bigger IGBTs, just like my hacked VF-S11. That was only a PWM drive though. 

Someone like Stiive or PSTechPaul would probably know more specifics on hacking a DTC drive


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## DDDvvv (Apr 2, 2012)

how many horses does that abb drive throw out? whats the ratings?


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## subcooledheatpump (Mar 5, 2012)

Rating is 70 KVA at nominal voltage and current, my calculator says 65280 watts 
(680*96)

At maximum current and voltage, 74942 watts (707*106) These assume A power factor of 1, of course.

Nominal input voltage 480 VAC, 680 VDC
Maximum input voltage 500 VAC, 707 VDC
Heavy Duty Current 65 Amps
Nominal Current 96 Amps
Maximum Current 106 Amps
Trip Current 195 Amps

So with the right batteries, I'm looking at about 100 HP. As I said before, the batteries I have now limit me to about 50 kW, 66 HP


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## subcooledheatpump (Mar 5, 2012)

Okay, now that the van drive systems are sorted out, I'm trying to do some research as to how much power it takes (Whr/mile)

I drove the van 2 miles, a few hills along the way, outdoor temperature 52F

This was the pack voltage when I left; 667.1. Divide by 50 batteries that would be 13.342 volts per battery








Then when I returned; pack voltage was 633.7, or 12.674 volts per battery









From what I can see on the internet, a lead acid battery is at 100% state of charge with 12.6 volts.This is puzzling.. So I have extracted energy from the battery pack, but how much? 

My drive isn't much help, my kwhr meter apparently isn't working...

Also updated the front page with new information.


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## Ziggythewiz (May 16, 2010)

Every lead battery is different, so full V for one is not the same as another. 52 degrees will also be much different than 80. 

Mine are full at 13.2 and half empty at 12.6.

What kind of kWh meter do you have, and how is it connected?


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## subcooledheatpump (Mar 5, 2012)

The VFD has a built in kilowatt hour meter. It has registered some power on the meter, as the drive is used, but I can't seem to make it move. It could be that it needs to be connected to 3 phase input for the meter to work.. 

Given that information I take it there is no easy way to measure the energy used other than a real kWhr meter... well thanks for the info about the battery voltages. Any other help with how I go about measuring energy would be appreciated. 

Ultimately, I'd like to get the range of the van to something like 15 to 20 miles and have a discharge current of atleast 100 amps, 200 would be better. The batteries I have now I don't think can do the first, and I know for sure can't do the second.... not for long anyway. I'll have to come up with some method to measure how much energy it uses to estimate how much I'll need to meet my range goals


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## Ziggythewiz (May 16, 2010)

It may be you just didn't drive far enough to move the meter. Is there any way to reset it? Maybe it would give fractions if not taking up 6 digits for the running count.

If not, I'd recommend a JLD404. Under $100 all in and both an informative and powerful little gadget.


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## Ace_bridger (Nov 22, 2011)

...or just use a domestic Kwh meter and plug the charger into that. Monitor how miles you did and then monitor how many Kwh it takes to the charge the pack pack up. Divide one by the other and bingo, wh/m.

I got my Kwh meter for the quivalent of $9 from ebay and I can monitor charge current, volts, VA, Kwh...errr, Frequency...cost to charge. It give me a good idea about what exactly the charger is doing.

Hope this helps...if not, ignore!


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## subcooledheatpump (Mar 5, 2012)

Good idea, thanks for the tip.

Only one problem, My van also charges the accessory batteries when it charges the traction battery. That may be alright though, it would give me an idea of overall energy used. I could always unhook the accessory batteries during the charge test and monitor the voltages of the batteries, then stop recording once they reach their previous voltage. something like 670 volts


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## cts_casemod (Aug 23, 2012)

Great project. 
Trouble is finding VFD with real IGBTs as most use smart modules ($$$$).

When you say 75KW...? With 100Amps IGBTs? Mine has 50Amps for 15KW with 120% peak and another one with 70Amps IGBT with 180% peak.

I am wondering what would happen if you hook your drive to half the voltage? I converted mine to 320V but I am having current issues and just wondering if they wont be because of limited gate driving power. Car runs fine after initial startup but goes into current trip at startup. I always thought the unit should adjust voltage accordingly to avoid this.


Regards,
Carlos


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## subcooledheatpump (Mar 5, 2012)

I believe the drive I have now (ABB ACS 601) would have atleast 150 amp IGBTs. 

The nominal current is 96 amps, and usually the IGBTs used are rated for twice that. 

During Regen, the drive will start reducing braking torque at 770 volts DC. So I believe it could work at 750 volts and 100 amps (it can do 130 amps peak) for 75 kW

The old drive I converted (and destroyed due to stupidity) I believe could also do the same, it would turn off at 840 volts DC and the IGBTs I used were rated for 100 amps nominal, 200 peak.


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