# Open source ac vfd conversion



## subcooledheatpump (Mar 5, 2012)

You might want to read through my thread 

http://www.diyelectriccar.com/forum...ed-chevrolet-express-van-converted-70662.html

and Etischer's thread

http://www.diyelectriccar.com/forums/showthread.php?t=15363


Also, keep in mind each VFD is a little different than the rest. 

They all come with different gate drivers and different switching frequencies, this makes it difficult to take any VFD and convert it. You really need to get lucky and get one with the right gate drivers. 

I'm one of those few people who have converted a VFD and I'd be glad to help


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## Ziggythewiz (May 16, 2010)

Where are these $250 new AC induction motors?


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## subcooledheatpump (Mar 5, 2012)

Believe it or not at some surplus stores they sell pratically new induction motors really cheap. 

The motor I have in my van actually did cost me $250, but to this day I can't figure out why it was even at the surplus store I got it from. It looked brand new, no scratches, no chipped paint, nothing. 

Still even if you can't find a new motor you can find a good used one for cheap, much less than any "designed for EV" DC motor. Many people say "AC is too expensive" but they are only talking about "designed for EV" AC motors. Scrap yard industrial motors that still work are a good alternative, if you can spare the room and weight.


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## DDDvvv (Apr 2, 2012)

*choosing a suitable vfd*

thanks Subcooled. great conversions.
ill need your help.

i've been looking at the allen bradley 1336 drive. it looks promising because it:
supports sensorless vector control 
is readily available (ebay)
is very affordable
accepts a dc input
230v ac available (300 dc)
changeable logic input boards, to even support motor encoders.
manuals and app notes readily available.

im open for ideas about any other vfd drives suitable for this project.


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## subcooledheatpump (Mar 5, 2012)

*Re: choosing a suitable vfd*

DDDvvv, you might want to get a 1336 drive from between 2 to 10 HP and take it apart and take some pictures. If you can show me what you're working with I can try to help you understand the insides of it. 

Also how is your knowledge of IGBTs and power electronics in general? You'll have to make an IGBT inverter assembly, the drive will be generating the signals, but you'll have to provide the correct hardware and hardware setup.

One last thing, the Toshiba VF-S11 7 to 10 HP drives are perfect for conversion, except for no encoder input. The VF-AS1 would have that though


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## DDDvvv (Apr 2, 2012)

*Re: choosing a suitable vfd*

electronics, no problem. power electronic projects are my second passion, next to programming 8 bit pic microcontrollers. i went with the 1336 because of the many input options available.

i just bought two 1336s hp drives @ $30 each. ebay item #330378811150. the guy has like 27 available. i could not pass on that. since it does not come with a controller, i also purchased a ha2 programming controller.


i also checked out your toshiba vf drive, but i 've invested alot of research time on the 1336 drive. thanks for the advice.

what did you replace the current sensors with?


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## subcooledheatpump (Mar 5, 2012)

*Re: choosing a suitable vfd*

The current sensors I replaced with HAS 100-S hall effect current sensors

They don't seem to have any left on ebay where I got mine, but these will also work

http://www.ebay.com/itm/LEM-HAL-100...-Cur-Measuring-Range-/190635745485#vi-content


I've tested both HAS 100-S and HAL 200 current sensors and they both work with the drive. I just stuck with the HAS 100-S because it works well with the drives' current limiting stall protection feature with respect to the motors abilities.


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## DDDvvv (Apr 2, 2012)

*Re: choosing a suitable vfd*

thanks for the reply. for days, ive been scratching my head about current sensing, and you just gave me a solution. i think my mistake was searching for one at mouser.com where they cost upwards of $260 each. 

here's my plan;
*the 2 vfd's arrive sometimes this week
get them running on 240v ac 
*familiarize myself with tuning/programming the vfd#1 while concurrently dismantling and planning with vfd#2 (i ordered 2)
*construct the igbt power module
*install / run modified power module
*move from 230v ac to dc
*buy a more powerful induction motor (im using a 5hp induction motor currently)
*buy donor car
*install.

my main plan is to save money on controller and motor. this savings will go towards a better (newer?) donor car or lithium battery system.

enough of daydreaming!!!
i wish i knew the model number of the igbt module in a 1336 drive. i have a bulletin 1333 drive .75hp and im wondering if its the same. this way, i can start shopping for modules with same characteristics.


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## subcooledheatpump (Mar 5, 2012)

*Re: choosing a suitable vfd*

Yeah you save alot by going with a DIY VFD conversion

Can't wait to see your work with these drives. I wish more people would get into this, we need all information we can get.


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## DDDvvv (Apr 2, 2012)

*vfds just arrived*








finally the vfds are here. had to buy the programming terminal separate for around $30.

wifes got big plans for me all weekend long so they get to rest before their teardown.


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## JRoque (Mar 9, 2010)

Nice thread so far! 

I experimented with a Hitachi VFD some time ago. I have all the parts including 6+ IGBT 600V/400A, current sensors, copper bus, caps, snubbers, etc. My backup plan was to use the PM600CLA060 and ​BP6A-L driver. In the end, I thought I would be better off buying an off-the-shelf solutions like Curtis'.

The high DC bus voltage is a main concern. At 600V, there are special precautions needed for routing wiring - ask a European about their regulations. To get to the higher voltage, you need more cells. This translates into higher battery pack cost and, more importantly, added weight. Converting 600V to 12V to run the rest of the system will require a custom and/or expensive solution. Or a separate pack as depicted on this thread. The motors should also be rated for VFD which means they have higher level insulation and can safely spin faster, too.

If you're running your motor in vector mode, was it easy to find the VFD feedback board and shaft encoder for your motor?

JR


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## subcooledheatpump (Mar 5, 2012)

Higher voltage might be more dangerous, but it would make the vehicle more efficient.
Less lost to heat in the wires, lighter wires too.
More batteries means more energy, that means greater range and more power. 

Of course you can go with many smaller units, instead of fewer largers ones. 

The motor insulation problem isn't a big issue in EVs where the cables from the motor and to the inverter can be made short. It's a bigger problem in industry where motors are sometimes Kilometers or even miles away from the VFD.

I don't see an issue with high voltage really though. I've never had an accident with my 600V+ system. Just don't touch it, and don't create obvious short circuit hazards.


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## DDDvvv (Apr 2, 2012)

finally desoldered the main igbt module in vfd1. took 30 minutes with a 100watt iron and desoldering pump.

no broken traces. hopefully, I can have the same luck with the rectifier module. 

meanwhile, ive been running vfd2 on a 5hp motor, getting familiar with control. I get a overcurrent fault at speeds less than 10hz
. with no load. still tweaking the programmer.


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## subcooledheatpump (Mar 5, 2012)

Nicely done, you mind sharing the IGBT model number? 

Are you using any torque boost on the VFD2?

Can't wait to see more


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## DDDvvv (Apr 2, 2012)

here is the uprooted module. 30amp 600 v module.








this are the replacements. 300amp 1200v modules from prx. looks like the
heatsink I planned to use for them is too small.









this are the plan-b modules. 75amp 600v intelligent modules by fairchild. they call them fsam75sm60a. built in protection, gate drivers and isolators. costed around 20 bucks a pop. (ebay) parallel 10 of them to drive 750amps.


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## DDDvvv (Apr 2, 2012)

unfortunately, current software version does not support torque boost. im planning to upgrade the software soon.


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## subcooledheatpump (Mar 5, 2012)

Looks like as is the case with most intelligent modules, the FSAM75SM60A's will actually start conduction with a negative gate signal, and stop with a positive signal. Opposite the way of a normal IGBT. You'd probably need a hex buffer to serve as a signal inverter to use the intelligent modules


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## DDDvvv (Apr 2, 2012)

yes. this one will need a 7408 to invert the input signal. ive been using them for medium dc motor control with no issues at all. very simple to implement.


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## DDDvvv (Apr 2, 2012)

spent the last two days drilling cutting and measuring. this is the housing for the poject. 

the reason for all the power modules is because im planning (later) for an all in one controller, charger and hv converter.

still need to drill for module support.










this is my donor vehicle. a 1998 astro cargo van. been sitting at my backyard for 2 yrs. i changed 2 fuel pumps in six months, and finally gave up on it. wife has been occasionally nagging me to take it to the junkyard.

hey Subcooled; what different thing would you do about your conversion?


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## subcooledheatpump (Mar 5, 2012)

You mean if I had to change something what would it be? and would that be in refrence to the controller or the whole project?

About the van in general; I'm in the process right now of getting a bigger motor, since the van I have is extra heavy (almost 8000 lbs?) that should give me better acceleration. also more batteries

The controller; I need a controller with torque mode+vector mode. The one I have now only does speed control with sensorless vector. Speed control works to a certain degree. I can't however, step on the hydraulic brake, then start back on the accelerator with the van still rolling. That creates a synchronization problem since the motor must coast during hydraulic braking to avoid a conflict of the motor fighting the hydraulic brakes. Regenerative braking serves to elminate most of those problems though. Just letting off the accelerator and letting regenerative braking stop the van seems to be adequate for normal driving situations.

So I should have converted a controller with torque mode and vector mode so I can use regenerative braking to assist the hydralic brakes. Then resume acceleration even if the van is still moving.


Side note: those astro fuel pumps are a pain. My dad had one he used in a business. The thing went through 6 fuel pumps before he realized what I told him was correct; the stock wiring harness to the fuel pump causes problems and has to be cut. 

You're converting it though so it's not an issue.
I also played with an old astro once, put an electric motor in it. It worked pretty well but it was in bad shape so I scrapped it.


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## DDDvvv (Apr 2, 2012)

i meant as the conversion in general . thanks for the reply.

im having the same problem in sensorless vector control in my tests (ac 240v on unconverted vfd). if i take motor to high speed, then stop the vfd, i have to wait until the motor comes to a stop, before trying to reapply power, else i get delays and vibrations and overload faults.

ive been fighting with this for the last week, and im beginning to think that the solution is a vfd with true torque control also. ofcourse, this would mean a different vfd. thats why im holding off on the conversion, until i can figure this out.

yes, astros are a pain. there's whole forums dedicated to their problems out there. this one weighs around 5000#, no rust at all. previous owner sprayed that protective stuff on underside and inside all panels. and since it was headed to the junk yard, its like a free donor car.

i just ordered a brand new baldor motor for $495 on ebay (free shipping). its 20hp, ~1800 rpm and its the lightest 20hp i could find out there, weighing 220#. i plan on opening it up, to hook it up to delta, like those aussies, and running it at 120hz , to double the nominal horsepower rating.

still beats spending $2000+ on those warp motors that everyone is trying to lick....


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## JRoque (Mar 9, 2010)

Hi. Does your VFD have an auto motor tune function and have you run it? I've had good results with a Hitachi SJ300 VFD. I can run tests in sensorless mode and set the amount of regen current to stop it. I can slow it down and speed it up without issues. For EV applications, you'll likely need full vector mode and that's why I was asking if you had found a sensor board for your VFD and encoder for your motor.

JR


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## aeroscott (Jan 5, 2008)

I have been wondering about taking any good VFD and changing brain ( vector chip etc) .


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## DDDvvv (Apr 2, 2012)

JRoque said:


> Hi. Does your VFD have an auto motor tune function and have you run it? I've had good results with a Hitachi SJ300 VFD. I can run tests in sensorless mode and set the amount of regen current to stop it. I can slow it down and speed it up without issues. For EV applications, you'll likely need full vector mode and that's why I was asking if you had found a sensor board for your VFD and encoder for your motor.
> 
> JR


i cant find any autotune features on this vfd's. i also think that the encoder route is the solution for ev applications (for this drive). luckily, encoder boards are available. im in the process of ordering one. on the other hand, i could just use decelleration. thanks for the advise. i just read up on that hitachi drive. lots of goodies in it.



> I have been wondering about taking any good VFD and changing brain ( vector chip etc) .


its doable, but you might need full schematics, for the donor vfd, play around with desodering high pin count surface mount chips, and 16 or 32 bit programming resources - a major headache for me. this particular vfd uses a 16 bit 84 pin chip, which integrates all the functions.


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## DDDvvv (Apr 2, 2012)

@ Jroque 

about the encoder, there's no specific encoder needed. the encoder board will accept anything from 1 ppr to 4096 ppr, quadrature or single pulse. just specify in the encoder setup what you got. encoders are not that hard to source. the only hurdle will be adapting it to your motor shaft. im planning on doing this with my lathe.


good news; tuning problems finally solved. the problem was that the acceleration rate was set at 10 seconds (drive default; time it takes to get motor from 0 to 60 hz) and this was really confusing to the sensorless module. took that all the way to zero, and drive runs like a dream. stopping, running and resuming at any speed is all possible. no overload faults anymore. i tried the full reverse test several times ; take drive to maximum, then hit the reverse button to get drive to maximum speed on the other direction. took 3 seconds, and a screeching sound. (you will never get to do this on an ev, even on emergency regenerative braking).

moving on to the power module construction.


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## mizlplix (May 1, 2011)

I am interested in the motor side mods.

Kevin in Topeka runs a HUGE Baldor motor (400#) with the Curtis controller used in AC50 drives. It is in a full sized pick up. It uses the 4 speed auto trans and runs well.

I was wondering about a maybe-future upgrade for the AC50. It would need to be somewhere in-between (AC50 and that giant Baldor).

Could you guys elaborate on motor selection and mods, please?

Miz


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## DDDvvv (Apr 2, 2012)

that ac50 motor looks great, 50hp (peak) @ 115 pounds. i think it uses a curtis 1238 controller. but for me, it costs a fortune; $4000+ for the motor alone.

im not equipped to give ac motor advice as of now. the motor mod idea is gained from the australian ev forums, who are waaay ahead of everyone in the ac industrial motors for ev game. from what ive read, majority of ac motors are wired for star configuration. the trick is to find the center of the star, or wye (virtual neutral), bring out the wires, and rewire for delta. current rating doubles, voltage required is halved, speed remains the same. with voltage halved, you have the option to run the motor at double the frequency = higher power outputs.

i dont know what horsepower ratings you are interested in, but they suggest a 2-pole motor ( ~ 3500rpm) if using a transmission, and a 4-pole (~1800rpm) if going direct drive. this is a fact they have tested. 

please read up on it to confirm (and correct me if im wrong) before making a decision. im going with the 4-pole direct drive idea. my new motor has not yet been delivered. i will document any mods on the motor.


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## rochesterricer (Jan 5, 2011)

DDDvvv said:


> that ac50 motor looks great, 50hp (peak) @ 115 pounds. i think it uses a curtis 1238 controller. but for me, it costs a fortune; $4000+ for the motor alone.


Actually, that price is not for the motor alone, it is the package price for the motor and Curtis controller together. Example:

http://www.evparts.com/products/str...8-to-96-volt-street-vehicle-motors/mt5615.htm


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## subcooledheatpump (Mar 5, 2012)

Thanks for posting your findings, DDDvvv. 

I was thinking of doing the same thing with my van, set "ACC" time to 0, that way I can just floor the pedal after braking and the drive will instantly spit out a high frequency. 

I believe you are right about the aussie guys and their motors as well. They all say you can attempt to do that yourself, mod the motor, or get it rewound at a shop. 

However, if you've got a 480 volt drive and a 240 volt motor, there is no need for any modifications as long as your drive can output the current required for peak torque. 

The only real downside is that going to half the voltage on a motor will require twice the current to make full torque.


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## DDDvvv (Apr 2, 2012)

current sensors just arrived. did some more drilling and wiring. wife just kicked me out of the dining room, because its becoming a huge mess. so its back to the little basement dungeon, with bench full of other unfinished projects. this is the mess;








@ Subcooled
what are you using for line chokes and spike suppression? im trying to wind my own inductors. I think we need transient filters on the main bus, to protect the power devices. the 75hp and above drives incorporates a bunch.


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## subcooledheatpump (Mar 5, 2012)

I do have some inductors from an old 30 HP VFD, I'm not using them but I am thinking about putting them in. So far at about 50-60 kW I'm not having any problems, I think the inductance of the battery loop might be enough to keep the voltages from the battery fairly stable during switching. I still get noise in the AM radio though.

Your power electronics section is looking really good so far, looks like you might be trying for a laminated capacitor bus?


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## DDDvvv (Apr 2, 2012)

the two big caps are 10000uf each, but at 250v. will be series tied to get 5000uf @ 500v.
will work for testing purposes, and then later, replace with a 20000uf bank. 

about the inductor, im hitting the hardware stores for high current inductor ideas. I need a copper or aluminum strip. one thats easy to roll.


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## aeroscott (Jan 5, 2008)

DDDvvv said:


> i cant find any autotune features on this vfd's. i also think that the encoder route is the solution for ev applications (for this drive). luckily, encoder boards are available. im in the process of ordering one. on the other hand, i could just use decelleration. thanks for the advise. i just read up on that hitachi drive. lots of goodies in it.
> 
> 
> 
> its doable, but you might need full schematics, for the donor vfd, play around with desodering high pin count surface mount chips, and 16 or 32 bit programming resources - a major headache for me. this particular vfd uses a 16 bit 84 pin chip, which integrates all the functions.


My thinking was gutting to the driver cards , If I remember right , the driver cards are just depending on the signal from processor . And the drivers have some of the protective systems . I"M studying power electronics web casts on you tube and test instruments will move into control systems soon .


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## idarusskie (Feb 17, 2011)

Interesting thread.
I have been thinking along this line as well.

My wife works in a motel and I was noticing that the washer they have ( a 60 lb extruder) has a VDF and about 10 different spin speeds. the motor is 5 horse 3 phase motor. Sometimes you can find these units that have been scraped.

my question. how big of a motor do you need? Is there a thread on horse power calculations?


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## mizlplix (May 1, 2011)

As I am functionally non-literate in electronics, I wish all of you good and I sincerely hope you combine your talents to this field.

We in the EV community need a higher voltage, 1000AMP AC controller/inverter to plug the big gap between the Curtis line and the "top end" offerings from others.

The motor side is being researched by our Aussie friends. They are light years ahead of us in AC motor mods.

Miz


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## DDDvvv (Apr 2, 2012)

aeroscott said:


> My thinking was gutting to the driver cards , If I remember right , the driver cards are just depending on the signal from processor . And the drivers have some of the protective systems . I"M studying power electronics web casts on you tube and test instruments will move into control systems soon .


yes, this vfd has a separate driver/output board. contains a good dc flyback converter, which powers all the low voltage needs, with isolated windings to power each of the three igbt high side drivers. im looking at it closely for future projects. success in your studies.



> I have been thinking along this line as well.
> 
> My wife works in a motel and I was noticing that the washer they have ( a 60 lb extruder) has a VDF and about 10 different spin speeds. the motor is 5 horse 3 phase motor. Sometimes you can find these units that have been scraped.
> 
> my question. how big of a motor do you need? Is there a thread on horse power calculations?


scrapped vfd's = free parts, like power driver boards, hv modules, caps, etc, which can be reused/converted. go for it.

i think there's a sticky on motor calculations on this forum.



> As I am functionally non-literate in electronics, I wish all of you good and I sincerely hope you combine your talents to this field.
> 
> We in the EV community need a higher voltage, 1000AMP AC controller/inverter to plug the big gap between the Curtis line and the "top end" offerings from others.
> 
> ...


thanks for the wishes. later, after the success of this project, im moving on to a 480v or 575v vfd. just like subcooled, i think that a lot of gains will be realised if voltage is increased, instead of current. all we need is a very powerful simple hv converter. thats on the works too. toyota did it, i can do it too. in fact, toyota's prius system jacked up the bus voltage to 650v on the 2010, from 600v on previous years models. they must have figured out the advantages of reduced system current.

the aussies are working hard on the ac motors, short of testing them on wind tunnels. nice research considering the limited voltage options of their induction motors. here in the states, we can choose between 200v, 240v, 240/460v, 400v, 575v etc, at any horsepower rating, and they are all over the place.

im reading up on snubbers and igbt protection. its scary when you learn about the stresses on this devices during switching. especially where 100 amp + currents are involved. ill order some snubber caps, before powering this up.


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## aeroscott (Jan 5, 2008)

went on You Tube, power electronics lecture , found C Deep , Prof.B.G. Fernandes , Lectures 1 threw 43 about 1 hr. each . starts very basic but detailed goes on to very advanced , lecture 9 gets into igbt's ( 25 minutes into it) . snubers are talked before #9 but with intro of igbt's will be talked in very great detail uper 30-43 gets into space vector modulation . The Indian/ English is very hard to understand at times , but Fernandes is much better ten some you can listen to . sound quality varies . I found this while on WWW.eevblog.com by Dave Jones on electronics has 200 plus vid's testing equipment ,tear downs ,etc. I highly recommend his series . Only wish I ran into this sooner . You'll love Fernandes use of the bird finger for counting . lol . And love what our Aussie mates are doing , Dave Jones will give you a good high energy aussie blast , he 's great fun . back to lecture #9


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## DDDvvv (Apr 2, 2012)

removed original current sensors, rectifier, and gate resistors. the gate resistors are 85ohms; prx recomends 1ohm minimum and 10 ohms max for the igbts im planning on using. im thinking of using 6.8 or 8.2 ohms. later, when I hook up the snubbers, im allowed to go down all the way to 1ohm. hopefully, I can start testing over this weekend, if kids give me a break....


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## aeroscott (Jan 5, 2008)

looking forward to your progress . In the near future I plain to have the test equipment to test this kind of mod.


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## subcooledheatpump (Mar 5, 2012)

Looking good, just make sure the original gate drivers can source that much current without blowing up. You'd be switching 15 amps peak with a 1 ohm resistor

It might be a good idea to add a few extra capacitors to the supply side of the gate drivers.(I did with my controller) V=L*DI/DT affects the gate drivers as well and you don't want the voltage to build up between the power supply and the gate driver input terminals


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## DDDvvv (Apr 2, 2012)

the 1 ohm idea was just a far thought. the gate dirvers are toshiba tlp250, rated for 1.5 amps. ever since i read its datasheet, i have been thinking of replacing the gate drivers (much later) to something like a 3120. i also thought of piggybacking two tlp250's to jack up the gate current. this will be much much later, pending results of initial conversion.


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## Randen (Apr 23, 2012)

Hello, Got here just in time. There's a beautiful S-10EV in my shop with a 360V Nimh pack charged and tested. I had bought it with issues the DC-DC converter was done. The nicely sealed box also housed a 3 phase drive for the on board heat pump. This portion is solved with an off the shelf converter and a china VFD. Now the Power Inverter Modual. This has some huge 750A IGBTs liquid cooled waiting to be drivin with a hacked VFD. The motor (liquid cooled) is another peice of art 85Kw with a single speed transaxle. I could use a little direction with connection of the hacked VFD. I'll get some pictues this week with schematics of whats there so we can proceed without me making some silly errors.

Thanks Everyone
Randen


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## aeroscott (Jan 5, 2008)

what motor is in your S-10EV , as I have the Ranger ev with dead battery and blown fuse , after I get my lithium pack installed I was thinking of changing out vfd like you are doing as the Seamonans is capable of lots more and not to thrilled with fords over control of max speed , min ac temp etc. Did yours have a 4x4 frame as the Ranger does .


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## aeroscott (Jan 5, 2008)

subcooledheatpump said:


> Looking good, just make sure the original gate drivers can source that much current without blowing up. You'd be switching 15 amps peak with a 1 ohm resistor
> 
> It might be a good idea to add a few extra capacitors to the supply side of the gate drivers.(I did with my controller) V=L*DI/DT affects the gate drivers as well and you don't want the voltage to build up between the power supply and the gate driver input terminals


Could you expand a little more on V=L*DI/DT . I'm newly studying this area having a hard time .Load= supply amps/ supply on time (load= average power) ?


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## Randen (Apr 23, 2012)

Aeroscott wrote:
what motor is in your S-10EV , as I have the Ranger ev with dead battery and blown fuse , after I get my lithium pack installed I was thinking of changing out vfd like you are doing as the Seamonans is capable of lots more and not to thrilled with fords over control of max speed , min ac temp etc. Did yours have a 4x4 frame as the Ranger does 

The Chev S10 EV is a basic S-10 with the drive train changed out to front wheel drive. It actually the same drive train as the EV1 but a derated motor. (85 Kw) All the electric production vehicles had a speed limiter. The electric S-10 has some interesting tech like a electrical operated heat pump and powerstreering (3phase motors) However in my opinion a little complex to try and maintain.

Randen


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## subcooledheatpump (Mar 5, 2012)

V=L*DI/DT (or V=L*ΔI/ΔT)
is a formula used to determind the voltage of an inductor when alternating current is applied

Voltage of inductor is equal to inductance times rate of current change (delta current/delta time)

The reason I bring it up in this discussion; whenever an IGBT switches, it is inevitably switching some inductance, so there will always be some kind of voltage building up higher than the bus voltage. If this is left unchecked, the voltage can exceed the IGBTs rating and destroy it. Like I was saying about the gate drivers, it affects them as well, since they are also switching some kind of inductance. Capacitors serve to counter this by absorbing voltage and turning the inductive charge into current instead. then the formula is I=C*dV/dT, or current is capacitance time rate of voltage change.

Oh and after I saw your post Randen, my van uses a 3 phase hydraulic pump for power steering and brakes as well, seems to me they work just as well as any other method


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## aeroscott (Jan 5, 2008)

Randen said:


> Aeroscott wrote:
> what motor is in your S-10EV , as I have the Ranger ev with dead battery and blown fuse , after I get my lithium pack installed I was thinking of changing out vfd like you are doing as the Seamonans is capable of lots more and not to thrilled with fords over control of max speed , min ac temp etc. Did yours have a 4x4 frame as the Ranger does
> 
> The Chev S10 EV is a basic S-10 with the drive train changed out to front wheel drive. It actually the same drive train as the EV1 but a derated motor. (85 Kw) All the electric production vehicles had a speed limiter. The electric S-10 has some interesting tech like a electrical operated heat pump and powerstreering (3phase motors) However in my opinion a little complex to try and maintain.
> ...


I didn't realize they went front wheel drive , nice . I would like to see some pictures of that system . I was thinking of adding a Prius transaxile to the Ranger to make it 4x4 . What problems do you foresee with the accessories .


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## aeroscott (Jan 5, 2008)

subcooledheatpump said:


> V=L*DI/DT (or V=L*ΔI/ΔT)
> is a formula used to determind the voltage of an inductor when alternating current is applied
> 
> Voltage of inductor is equal to inductance times rate of current change (delta current/delta time)
> ...


Thanks I need to see some vids to help it soak in .


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## DDDvvv (Apr 2, 2012)

those snubber capacitors are taking forever to get here. no progress until I get them.

on another note, I picked up the 20hp motor, 45 miles away. so much for ebay free shipping. o well its here now.








took me 30 minutes to get it downstairs. weighs 230 pounds. I guess im not as young anymore. bracing myself for sore musles.

took it apart immediately, to analyze it for any mods.









I set my sights on a heavily taped area, attacked the varnished fabric and tape, (carefully) and I was rewarded with this









the blob of copper connecting the wires is the centerpoint of the star or wye winding, the virtual neutral. im sooo happy...


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## Randen (Apr 23, 2012)

Here is the drawing illustrating the IGBT connections on the Delta igbt modual and the delpi IGBT pack. The truck is in perfect condition but like all the rest about 15k miles on it and something goes wrong. Too bad, it is a nice system but now no support and no parts avalible. I would like to drive the Delphi IGBT with the delta VFD. 

Thanks Randy


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## Randen (Apr 23, 2012)

The picture are the 85 Kw liquid cooled motor mounted to a single speed transaxle. The motor/transaxle has a resolver and the park/drive gear selector is complemented with switches to select back/forward or disable when in park or neutral. also some temp sensors. Very nice package.

Randen


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## Randen (Apr 23, 2012)

*Photo of Delphi IGBTs*

Again a very nice set-up the IGBT's are mounted inside a liquid tight enclosure against a liquid cooled heat sink. The copper busses are precision formed with snubbing and huge electrolytic's buffering the spikes and induction voltages. Can't wait to drive by the gas station.

Randen


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## Randen (Apr 23, 2012)

*delta VFD*

A photo of the delta VFD. I've tested and operated it on the 350VDC. driving a small 3 Ph. motor. Has some neat profiles to tune the operation. Hope this can be integrated as I know this one the best.

Randen


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## Randen (Apr 23, 2012)

*S-10 ev*

The truck came to me with a DC-DC converter problem that has plagued the little truck fleet. There are so many safety interlocks with GM propietary language that is almost imposible to crack. If the air-conditioner doesn't work you can't charge it. If the DC-DC converter doesn't work you can't drive it. Hmm, on a gasoline version if the red oil light comes on you "can" drive that, for for a short while anyway. I would like to simplify it, the onboard charger looks after the batteries. The VFD drives the truck, the aircondition will be driven by a seperate VFD. And the DC-DC converter will be an off the shelf brand $220.00 instead of the $3400.00 GM replacement.


Randen


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## palmer_md (Jul 22, 2011)

what's up with the hijack? it is getting confusing with two authors.


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## DDDvvv (Apr 2, 2012)

@Randen
you are lucky to get a big headstart with that factory produced ev. i would hook up straight to those gates. i would probably pre-test out of vehicle first, with equally rated different igbt's, on a different motor. i dont know if you will have to switch the current sensors. 

on another note, im still not qualified to advise you on this issue, since i dont have a modified inverter yet. Subcooled might be able to help. thanks for the posts and pics.


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## subcooledheatpump (Mar 5, 2012)

@Randen, Did you get my reply to your PM? If you can send me a close up of some of those IGBTs I might be able to help you. Also the original IGBT# from the delta VFD. 

The inverter looks like it has 6 IGBTs like expected, but the diagram is a bit confusing. I think I have an idea whats going on but some more pictures of the actual inverter would be helpful


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## Randen (Apr 23, 2012)

*Delphi controller*

Yes the delphi has a total of 6 IGBTs. 2 for each phase. What would you like to get a close-up of? I did get the PM and responded Thanks

Randen


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## DDDvvv (Apr 2, 2012)

life got too busy. 

i decided to change the original design, to this design









the previous design was getting too heavy. it had a 24 x 12 x 3/4 inch aluminum plate and only 5000uf worth of bus caps. in any case there was not much room for charger/converter. (too ambitious). so i decided one project at a time. 

design 2 has space for 24 @ 1000uf x 450v. (@ $1.35 each, ebay), is smaller and much lighter. now to the drill machine.


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## PStechPaul (May 1, 2012)

I just found this thread and I plan to watch it with interest. So far I'm just working on a little utility vehicle and a garden tractor for electric conversion, and I am using a DC bus with a standard VFD and three phase motor. I'm also thinking about overclocking the motor and using a higher voltage for a HP boost. I even have a small motor that I rewound from a single phase 120V to three phase 8 VAC 12 pole, and overclocked it to 4x.

One thing I wanted to comment on is the large capacitors you are using on these VFDs. If you are running on pure DC from batteries, you shouldn't really need very much, unless you are looking for short-term surge power. I have about 1600 uF on my 320 VDC link, with a 2 HP VFD and motor, and I figure that will give me about 82 W-seconds, or only about 50 mSec at 2 HP (1600 W). They are critical for a VFD running on single phase AC, of course, but with three-phase input you only need to hold the voltage near peak for about 1.5 mSec.

I'm using a DC-DC converter which transforms 12 VDC to 320 VDC, using a square wave at 500 Hz, with deadtime of only 2 uSec, so a full wave bridge would not need much capacitance at all. But I'm using a doubler circuit for the 12 VDC input, so I need some capacitance. But at 500 Hz, it's only for 1 mSec.

Looking forward to hearing more about your conversion projects. Someday I hope to do an electric conversion for a highway vehicle, but for now I'm happy enough with my 1999 Saturn SL1 which averages 35 MPG and can get over 45 MPG highway.


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## subcooledheatpump (Mar 5, 2012)

The capacitors aren't for smoothing input AC or for smoothing battery current/voltage. 

They are for absorbing voltage spikes during IGBT turn off. The Capacitance needed is proportional to the current being switched. More current means more capacitors. 

Just in my personal experience, I've noted that switching 100 amps will require 36000 microfarad, thats what I have in my own modified VFD controller. I've blown quite a few IGBTs using less than that.


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## PStechPaul (May 1, 2012)

I've tried to find more information on the sizing of the DC link capacitors and the failure modes of IGBTs. The following article explains quite a few details of a large VFD and it only describes the capacitors as needed for smoothing the rectified AC. But it also mentions snubbers for the IGBTs and inductors and filters for smoothing the voltage supplied to the motor. It also shows the use of a dynamic brake, which is used to dissipate the kinetic energy stored in a rotating motor when stopping.
http://www.danfoss.com/NR/rdonlyres/B07BD285-5895-48C9-AB04-2B0FBED854F6/0/vfdlesson3.pdf

Here is the list of the lessons:
http://www.danfoss.com/North_Americ...d+Education/AFD-101+for+Industrial+Market.htm

Has anyone looked at the waveforms of drives to compare the effects of link capacitance? I have a feeling that the failures may be due to high frequency switching transients, which are best handled by snubbers. And there also needs to be some smaller non-electrolytic capacitors across the DC supply of the bridge, with very low inductance and ESR at high frequencies. You might be able to use, say, a 0.47 uF polypropylene or metal film capacitor to reduce the high voltage transients.

Here is a detailed analysis of IGBT characteristics and failures, and snubbers:
http://www.fairchildsemi.com/an/AN/AN-9020.pdf

And other possibly helpful resources:
http://www.toshont.com/ag/vfddesign/ag_15_igbts.pdf
http://www.toshont.com/vfddes.htm
http://www.toshont.com/ag/vfddesign/AG40EM.pdf (specifically about DC link capacitors)
http://www.electro-tech-online.com/...-reviews/95988-rcd-snubber-igbt-inverter.html (discussion of DC link bypass and snubber capacitors)

Some of this information may be especially important for DIY modified drives. I have learned a lot just from an initial scan of some of these documents.


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## subcooledheatpump (Mar 5, 2012)

http://www.ebay.com/itm/Lot-Of-10-A...532?pt=LH_DefaultDomain_0&hash=item2ebc947134

These are your best bet as far as film snubber capacitors. I personally use 3 of them in my modded VFD

Also about sizing the capacitors; thats a little tricky but it usually comes down to this: higher currents and higher switching frequencies means you need more capacitance. Since V=L*DI/DT, that means if we are switching more current (DI) and we are switching it quickly (DT) we will get more voltage at the IGBTs terminals and therefore more capacitance is needed to absorb it.

Slowing the IGBTs transistion from on to off works to reduce those DI/DT losses but that also means they will dissipate more heat 

This is explained in the articles above, and also 

www.mitsubishielectric.com/semiconductors/files/manuals/powermos4_0.pdf

Just to add to the list


If the bus inductance (L) is lowered that also means less capacitance is needed. 

I always stick to the basics though, bigger is better. I'd rather play on the safe side and have too much capacitance rather than too little and end up with hundreds or thousands of dollars of destroyed IGBTs


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## aeroscott (Jan 5, 2008)

PStechPaul said:


> I've tried to find more information on the sizing of the DC link capacitors and the failure modes of IGBTs. The following article explains quite a few details of a large VFD and it only describes the capacitors as needed for smoothing the rectified AC. But it also mentions snubbers for the IGBTs and inductors and filters for smoothing the voltage supplied to the motor. It also shows the use of a dynamic brake, which is used to dissipate the kinetic energy stored in a rotating motor when stopping.
> http://www.danfoss.com/NR/rdonlyres/B07BD285-5895-48C9-AB04-2B0FBED854F6/0/vfdlesson3.pdf
> 
> Here is the list of the lessons:
> ...


A few hours to get threw the Danfoss lessons , thanks good find!


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## PStechPaul (May 1, 2012)

Something else to consider is line and link reactors. They may not be as important for a battery powered DC link, but it would be worthwhile investigating. I searched again for information on link capacitors, and I did not find much more, but these came up:
http://emainc.net/newsletter/comparison-between-ac-reactor-and-dc-link-choke/
http://www.pge.com/includes/docs/pd...e/energystatus/powerquality/line_reactors.pdf
http://igor.chudov.com/manuals/Siemens-SED2-Harmonics-Capacitors.pps

The last link is a PowerPoint presentation that, in page 10 and page 16, describes problems caused by higher link capacitors, and they use a 20 uF plastic capacitor rather than a more typical 1000 uF capacitor in their 15 HP drive. It shows how this lowers the peak switching current and therefore reducing high frequency transients. Here is another document that explains more. I think it is more about transients and harmonics caused by AC input switching, however:
http://www.us.sbt.siemens.com/HVP/Components/Documentation/SI033WhitePaper.pdf

Here is an application note from Microchip that explains how insufficient link capacitance may cause an overvoltage condition due to regenerative braking. With a battery bank, this might not occur, but if there is a diode between the batteries and the DC link, or if there is significant lead impedance, destructive high voltages could be generated.
http://ww1.microchip.com/downloads/en/AppNotes/00887a.pdf

Here is an IEEE study of an alternate connection for regeneration ultracapacitors for greater efficiency. It's rather technical but might be helpful, especially since it directly addresses vehicular applications:
http://scholarsmine.mst.edu/post_prints/pdf/Lu_09007dcc805e9646.pdf

This is very interesting:
http://www.nrel.gov/vehiclesandfuels/powerelectronics/pdfs/program_review_6-7-04_dc_link_cap.pdf

I also found this youtube demonstration featuring a three-phase motor conversion:
http://youtu.be/2tFSVniO_Cc

Enough for now!


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## subcooledheatpump (Mar 5, 2012)

Some good info. 

That video you posted is actually etischers conversion, he's posted it on this forum too. 

There are also videos on youtube of my own working 3 phase VFD conversion

http://www.youtube.com/subcooledheatpump


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## PStechPaul (May 1, 2012)

Interesting. I posted a comment on your video. I'm working﻿ on an electric conversion for a riding mower / utility vehicle, and once I am comfortable with the design, I may scale up to a road legal vehicle. I am convinced that the induction motor is the best choice overall for EVs. I'd be interested in seeing your complete schematic and other technical details. The 600 volts of batteries would scare me. And I bet they are expensive, probably about $1500 for 10 kWH. I'd use 10 90 A-H deep cycles for about $800.

There seem to be many different approaches to electric conversions, and I'm trying to look at the big picture to see where improvements might be made and where the existing technology is more or less efficient. There are always tradeoffs and it's hard to say what is really "best". If you haven't seen my own little three-phase conversion, here's my video:

http://youtu.be/y0qWY4bVnEA


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## aeroscott (Jan 5, 2008)

PStechPaul said:


> Something else to consider is line and link reactors. They may not be as important for a battery powered DC link, but it would be worthwhile investigating. I searched again for information on link capacitors, and I did not find much more, but these came up:
> http://emainc.net/newsletter/comparison-between-ac-reactor-and-dc-link-choke/
> http://www.pge.com/includes/docs/pd...e/energystatus/powerquality/line_reactors.pdf
> http://igor.chudov.com/manuals/Siemens-SED2-Harmonics-Capacitors.pps
> ...


very good stuff. Thanks , I would like to see what happens to the harmonics with the 12 and 18 diode system and how they are implemented . I'm just having a hard time seeing how more diodes would change things , but it is obviously what happens , just more expensive seams to be the reason for not using them . Funny it's called a 6,12,18 step inverter just because of the diode count .


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## PStechPaul (May 1, 2012)

aeroscott said:


> very good stuff. Thanks , I would like to see what happens to the harmonics with the 12 and 18 diode system and how they are implemented . I'm just having a hard time seeing how more diodes would change things , but it is obviously what happens , just more expensive seams to be the reason for not using them . Funny it's called a 6,12,18 step inverter just because of the diode count .


My understanding is that they use additional transformers to obtain 6 phase or 12 phase power, with 60 or 30 degrees per phase. The magnitude of ripple drops and the ripple frequency goes up, making it easier to filter. But I don't think it makes that much difference, especially if you are generating an output voltage lower than the input.

http://www.allaboutcircuits.com/vol_3/chpt_3/4.html
http://www05.abb.com/global/scot/sc...67f3/$file/hillside plant reference sheet.pdf
http://www.joliettech.com/abb_evaluating-harmonics-with-ac-drives.htm


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## aeroscott (Jan 5, 2008)

thanks , In regeneration voltage will always be above buss voltage . Part of the issue with the diodes is the reflective voltage coming back to the inverter , putting high voltage stress on the igbt's . If I have this wright . I wonder if there's a way to get the phase shift with caps or something for regen on aDC buss. added : if caps were added to say the first 6 diodes ,and not to the second set , bigger caps to a 3ed set , etc . would the diode reflections be increased in Hz with less amplitude seen by the igbt and battery .


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## DDDvvv (Apr 2, 2012)

got a lot of wiring done. the capacitor bank was a headache and next conversion will use big caps for convenience.

powerex specifies to have their power modules close to the driver, and if not possible, twist the gate/emitter wires at 3 twists per inch. this cancels out any stray inductances that could be dangerous, to the gates.

all thats remaining is wiring the current sensors, and replacing the gate resistors. i hope to get that done today, and move out of dining table (once again!) . wife's causing hell.


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## subcooledheatpump (Mar 5, 2012)

Speaking of stray inductance, those wires from the capacitor bank to the IGBTs might cause you problems


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## DDDvvv (Apr 2, 2012)

all replaced with solid busbar. thanks for the heads up.









gate resistors are in. only thing holding me back is the connectors for the current sensors.
off to the junk pile.


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## peggus (Feb 18, 2008)

Those busbars won't help you though as they are also high inductance. You need a laminated bus or you're going to have a bad time...


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## Nathan219 (May 18, 2010)

Looks nice 
laminated bus structures
or look at the animations on this page to see what is being talked about. Great work!


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## subcooledheatpump (Mar 5, 2012)

Well the busbars are better but you've still got wires hooking your capacitors togther. Who knows, if you lower the switching frequency enough and go with the maximum gate resistor (that was 8 ohms right?) the voltage buildup might not be too much for the IGBTs. Lower current on the IGBTs will also help. Since the gate resistor can't be the minimum, there will be more switching losses which means more heat. Lower current though will help minimize that. 

I'd say try for 3 kHz switching frequency at less than 100 Amps for your first test 

Looking good though


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## DDDvvv (Apr 2, 2012)

finally powered it up. im using rectified mains 240v through a 30amp breaker

every time i power it up, it takes out the main 100amp breaker, lights out, controller powers up for 6 seconds, then ofcourse gives an undervoltage fault.

the cap bank appears as a short circuit to my wimpy 100amp load management box. i tried various series connected transformers, to act as chokes, but still getting same results.

tomorrow, will try to series connect the range element. it will be like a 2400watt resistor, which will limit the inrush/nominal current to 10amps. hopefully, this will allow for initial tests. now i know why they use them capacitor precharge circuits. since i cant get any sleep, might as well read up on precharging circuits.

**the caps in the bank are inter-connected by single conductor cable.


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## subcooledheatpump (Mar 5, 2012)

Yeah a simple precharge resistor will help you avoid tripping the breakers. You don't really even need a heating element. A small 10 watt resistor rated for about 20 ohms should do the trick, I use two in my van. Incandescent light bulbs work too. Just put a volt meter on the capacitor bank and connect it with the resistor in series and watch the voltage pull up. Once it's all the way up to about 340 volts, bypass the resistor with a relay/contactor.


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## DDDvvv (Apr 2, 2012)

finally powered it up.

20ohm 300w resistor shunted to a contactor. drive display cycles through power up sequence, then gives a ground fault. in the user guide, it means that one of the outputs grounded more than 100 amps, _while motor was running. _

now i know that this did not happen because i have a ammeter on the power input, and the 20 ohm resistor is still in circuit, and i never got the chance to run the motor.

unplugging the current sensors has a different effect. you get a blown fuse (to motor) fault.

so all clues lead to the current sensors, so i opened the drive board to investigate.

the current sensors that im using are not compatible with this drive. they are hal-300. they require +/- 15volts and 0 volts (ground).

the drive does not supply a negative voltage to the current sensors. its more like +30 volts. so the sensor outputs ~9volt. controller checks sensor output, if greater than 4.5 volts, then its positive going, and if less than 4.5, phase is swinging negative output.

so i did some research and tried to get replacement current sensors as close in characteristics (and pin count) as the original la25-np sensors. i found something close. lt300-s is the closest i could find (on ebay). snugged 10 of them for $25, from the same seller selling those snubber capacitors.


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## subcooledheatpump (Mar 5, 2012)

I see, it appears you have a current transformer transducer. Sounds weird but it is different than just a hall effect current sensor. I actually had the same problems at first with my VFD but I had the opposite sensors.

I originally got what you need, a transformer/transducer. Turns out I needed a hall effect current sensor. 

Keep us posted


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## DDDvvv (Apr 2, 2012)

oh no. its also a hall effect current transducer. looks like everything from lem uses the hall effect principle. thats how they are able to sense dc current. 

speaking of sensors, ups just delivered them. that was fast. ill get to test them later in the night.


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## DDDvvv (Apr 2, 2012)

*Success at last!!!!!!!!*

















finally powered the contraption after a whole evening of checking and rechecking all the wiring.

i put my safety goggles on, turned on the power, set the drive to 2khz at volts/hz mode, and pressed the run button then started ramping up the speed. 

motor kicked on and ran with no issues. makes a lot of noise at 2khz switch frequency.

after running it for a whole hour, i changed it to run under 4khz and the noise disappeared. ramped all the way to 60hz, with no issues. 

the test motor is a 5hp with noisy old bearings, and no load. will resume tests tomorrow. i know this does not mean alot and the real test will be performance under load. but its a start.

anyone with ideas on how to load this motor will be really appreciated. im thinking of coupling the motor to a 3hp dc motor that i have, and applying a load to the motor as a generator.


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## subcooledheatpump (Mar 5, 2012)

*Re: Success at last!!!!!!!!*

Congratulations, very exciting stuff to see. 

I'd be a little leery about increasing the switching frequency any more than 4 kHz with those monster IGBTs while doing a load test. As I suspected you've got the current sensors I originally got and they didn't work. 

Good to know, different drives take different types of sensors and now the EV community knows about hacking an allen bradley 1336 drive. 

overall very impressive. I'll be looking forward to some load tests and also some readings of the IGBT temperatures and seeing your final cooling system

oh and for loading, this might work, might not depending on if the VFD needs the feedback noise of a motor to work; you could hook a 3 phase heater, or a bridge rectifier to the output and connect a resistor to the output of the rectifier for a load test. Certain VFDs I have will run just about anything, I even have a VFD running a metal halide light with an old motor stator as a ballast.


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## PStechPaul (May 1, 2012)

*Re: Success at last!!!!!!!!*

Using the DC motor as a generator and driving heater coils seems like a good load. If you have an AC generator head, that's another option. And a big air compressor may also be good. It won't generate as much heat and you'll get useful work, but it's probably not a very constant load.

A datalogger would be helpful to record various parameters as a function of time. You can get some inexpensive data acquisition boards with 8 channels of A/D and software to take samples at regular intervals and then plot the results. And there are also USB digital storage scopes that can display the actual phase voltage and current waveforms.

I was going to do some power and torque testing on my custom wound motor, and someone warned me that I should be very careful. He suggested getting a heavy iron base with T-slots, as for a milling machine, and bolting down the motor and generator. Also recommended a blast shield. There is a lot of angular momentum in a fast spinning rotor and if it should jam the motor will tend to twist violently and may even explode. At least that's what seemed to be the danger. Good luck!


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## aeroscott (Jan 5, 2008)

I'm looking of a cheap way to log wave forms , harmonics etc. I was thinking of a Math/Lab type free ware .Can you point me in the wright direction on these data boards .


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## PStechPaul (May 1, 2012)

aeroscott said:


> I'm looking of a cheap way to log wave forms , harmonics etc. I was thinking of a Math/Lab type free ware .Can you point me in the wright direction on these data boards .


Here are some inexpensive packages:
http://www.dataq.com/data-acquisition-starter-kits/data-acquisition-starter-kits.htm
http://www.mccdaq.com/solutions/USB-Data-Acquisition.aspx
http://www.hytekautomation.com/Products/IUSBDAQ.html
http://labjack.com/products

and on eBay:
http://www.ebay.com/sch/i.html?_nkw=data+acquisition+usb
http://www.ebay.com/sch/i.html?_nkw=pc+oscilloscope
http://www.ebay.com/sch/i.html?_nkw=pc+data+logger

You may be able to use your sound card for two-channel data acquisition.
http://hardandsoftware.mvps.org/sound_card.htm
http://www.tmworld.com/article/319702-Sound_Cards_Work_in_Some_Data_Acquisition_Applications.php
http://www.mathworks.com/products/daq/supportedio14006.html

I am in the process of making my own. So far I have a PIC18F4420 driving an LCD display and 8 channels of ADC. They will read battery voltage and current, link voltage and current, joystick position, and temperature. The ADCs have about 150 uSec conversion time so they could be used to analyze waveforms. If you are looking at two channels at 60 Hz you could get 50 samples per cycle, and be able to see harmonics up to 1.5 kHz or so. You really need a DSO for that. 

Also, if you need to log data over a long period of time (like a 10 minute run), you need a lot more data storage, and a fast way to transfer the data to a computer. I intend to sample the data I am concerned about at a rate of about 10/second, so if I want five channels the conversions will be 50/second. At 10 bits each, using RS232, you need 2 bytes per sample, and each byte takes 10 bits with 1 start and 1 stop bit. So that is 1000 bits per second, which is well below the usual default COM rate of 9600 bits/sec.

I have a proprietary product that takes samples at 2500 per second, to analyze a 60 Hz signal, so I am using 57.6 k baud rate. I store the data as 16 bit integers, so a typical test of 10 seconds results in a waveform file of 50 kB. A 10 minute run would be 3 MB. And that is for a single channel.


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## Coulomb (Apr 22, 2009)

*Re: Success at last!!!!!!!!*



DDDvvv said:


> anyone with ideas on how to load this motor will be really appreciated. im thinking of coupling the motor to a 3hp dc motor that i have, and applying a load to the motor as a generator.


What would be ideal is if you can arrange for the DC generator to charge the DC bus. That way, you only need to supply losses from the mains or test pack, so you can run the motor at higher power. But you would have to be lucky to be able to get bus voltage from a DC generator.


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## aeroscott (Jan 5, 2008)

PStechPaul said:


> Here are some inexpensive packages:
> http://www.dataq.com/data-acquisition-starter-kits/data-acquisition-starter-kits.htm
> http://www.mccdaq.com/solutions/USB-Data-Acquisition.aspx
> http://www.hytekautomation.com/Products/IUSBDAQ.html
> ...


Great thanks so much you saved me a lot of searching . DSO's that I've seen like the HP 54542, 500mhz , 4 channel , about $450-up but need to find if the data can be transferred to the computer without much hassle .I'll start looking over the links , thanks.


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## Stiive (Nov 22, 2008)

Hi,
Great job so far. Just wondering if there's been any further progress?

I'm very interested in how you went with that capacitor bank? I'm looking at a metalized polyprop bank at a massive cost, but wondering how your DC bus ripple looks with that cheap eBay alternative. What is the capacitance you've ended up with there?


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## DDDvvv (Apr 2, 2012)

hi 
there's been no big progress on this project. the other day, i pushed the drive to output 30 amps continuous. no heat, no temperature rise at all. was running good, until the 30amp breaker on my mains distribution box tripped.


the caps are ok. i measured them before install, and they averaged 880 uf. no surprise there, since they are rated at 20%. i would get 4 of those 10000 uf caps on ebay if i were doing this again. (2 for $43)


i've been busy searching for a different donor car. wife says to get practical with my "stupid" electric car shennanigans. i cannot drive kids around in my planned conversion; a cargo van. "get a nice car, remember, we have three kids"


i think i found one. a 99 bmw 540i sport. the guy will take $1400. in pristine condition, but motor blew up. he took the motor out, to replace it, then ran out of money. so half my job is already done. he probably thinks im a sucker, i did not tell him of my plans (just incase he decides to not sell, and go electric). as far as he knows, im buying an engine and getting my buddy to install it.
here it is, in his garage. notice all the parts around, from the engine teardown.


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## Stiive (Nov 22, 2008)

Thanks for your reply. I look forward to hearing about any further progress.

That's a very nice donor car. I think here in Aus we have special rules with converting newer cars to make sure all the safety features (such as ESP) still work as intended. Maybe you should check into this in your area.

Apart from that, it'd be a very sexy conversion.


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## DDDvvv (Apr 2, 2012)

theres no rules, no inspections over here. as long as its registered and insured, no one cares what you decide to drive, or what you are driving it with.

yes, very excited about this car. back in 2007, i wanted this same model, nearly grabbed one, and then my financial situation changed. got a 2000 jetta tdi diesel instead. the tdi just got totalled. so the big interest in ev. 

the cost of maintaining the bmw brand of cars is ridiculous, and that was the greatest turnoff. and they feed on premium gasoline only!!!

i figured out that since the 4.4 liter motor is gone, life will be easier. it has been my dream car for the past decade, the car i would get if i won the lotto.

im picking it up this weekend, and the guy threw in a 2 ton hoist, and a low profile jack in the deal.


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## subcooledheatpump (Mar 5, 2012)

As much as I like the Astro (well, love/hate), I think the BMW will make a more interesting conversion. Can't wait to see more


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## JRoque (Mar 9, 2010)

Ah... the wife units. They all seem to be made from the same raw materials: arsenic and sandpaper.  

That is a nice car but did you see the curb weight on that thing? At 3,800 lbs it's not the lightest and that makes a big difference in your conversion costs. No doubt it will be nice though and you must love your car first and foremost if you're going to spend so much time and money on it.

Ask about the transmission - any grinds when shifting? You'll probably end up needing a new clutch but ask how many miles that one has. How's the diff? Brakes? Were all recalls done? Any serious accidents? 

There's a couple of guys here with Beemers that can give you pointers if you need them. Check the garage or evalbum.

JR


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## DDDvvv (Apr 2, 2012)

transmission is automatic.

still in the car, hanging on cables. my plan with the astro van was to go direct (differential) drive. so the tranny has got to go.

the differential ratio is 1:2.81 . will switch to a 530i differential, which has 1:4.10 gear ratio, interchangeable, and costs around $150.(used)

im not worried about the weight at all. its like a big upgrade from the 5000+ pound astro.

was planning agm, but now im thinking lithium.


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## DDDvvv (Apr 2, 2012)

*an easier conversion project*

last week, i thought of a easier idea about converting a vfd. 

there's the usual approach of getting a large drive ( 75hp +), tapping into the dc bus, and you are good to go. this is easy, but this drives cost a fortune ( $ 2000 + for a used drive supporting vector control, encoder, and computer interface.

what if you could get a very cheap 100hp drive, and couple it to a small cheaper drive?

i set out to do just that.









got this from ebay. reliance gp2000, 100 hp, 480v, working when removed from service, $150. had to pick it up 150 miles away, but it was worth it.

got it home and opened her up, and it was full of goodies.

















400 amp 1200v igbt's complete with laminated insulated busbars, and a large square d 250 amp x 3 contactor.

this drive weighs 260lb, and is in a 5' x 2' x 3' cabinet. so whatever plans i have would involve getting all this goodies out of this cabinet, and designing a smaller lighter housing.

after gutting, this is what i got:









from left:
power modules on large heatsink, with 300 amp fuse, and snubber boards
4 x 6800uf 450v caps
gate drive board
gate drive power supply
square d 250 amp switch
3 x 200 amp fuses.
size 1 assorted cables.

why gut it? this drive does not support vector drive, or any form of feedback. its old, and only does a blind v/f profile. (although it has current sensors on two of its outputs). so the control circuitry has got to be replaced by something more modern.

it has a powerful gate drive board, so im planning to tap into the gate drive. just the heatsink and power modules weigh over 100 lb, might have to be changed later, for weight saving. probably go watercooled.

interesting thing is, the power supply board takes 240v ac, although the drive is a 480v version. so im deciding between 230v or 460v conversion.
will probably go 460v since the current rating would have to double if i went with the lower 230v. 

looking and studying this components, im beginning to see the design requirements of high hp ratings in this drives. from gate drive design to insulation, snubbing, and wiring.

going this way is also a good idea, since the cost would add up, if these components were purchased separately.


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## aeroscott (Jan 5, 2008)

beauty! great source of parts.


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## DDDvvv (Apr 2, 2012)

finally got the donor. my father in law took care of the towing. thanks old guy.

all parked in my driveway which sadly will be my work zone. ofcouse, engine is missing. hopefully, thats a good headstart.

ill probably move to a new build thread.

the car weighs 4900 lb gw, but for $1400, i could not pass on this.


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## Stiive (Nov 22, 2008)

*Re: an easier conversion project*



DDDvvv said:


> from left:
> power modules on large heatsink, with 300 amp fuse, and snubber boards
> 4 x 6800uf 450v caps
> gate drive board
> ...



Nice one! What you thinking of doing for control? Could be a good KiwiAC candidate


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## DDDvvv (Apr 2, 2012)

i havent decided on control yet. im designing a hv converter, (200v to 650v buck boost) and im split between using this 100hp parts for that, and a 480v 1hp industrial vector drive. 

the advantage of this is, you can feed it with anything; dc motor pwm, ac, other high power project,you can even feed it with your svm design output, or any other output.

i have put this side of things aside for now, since im in the planning/design stage of trying to get that motor into the car. i wish i could multitask.


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## picaboo (Jun 11, 2012)

I think I missed some action. Just finished reading up the entire thread in one breath...

I will be following this thread with keen interest. I am an electronics engineer, worked 15 years in VLSI and embedded electronics. So, not much practical experience in power electronics. But I eat and sleep embedded programming.

I will appreciate if you share a schematic of your arrangement till date, before sharing your venture into the bigger drive? It will allow newbies like me to follow better. With just photos it is kinda hard to follow the details.

Excellent energy you have, no doubt. 

--Kish


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## DDDvvv (Apr 2, 2012)

havent checked this thread in a while. 

i dont have any schematics, and i never drew any. all i did was locate the base and emitter connections on the donor vfd, yanked out the small power module, and route the B E connections to a more powerful group of modules, while observing the phase arrangement.

but this particular donor vfd was not complicated at all. but be careful.


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## picaboo (Jun 11, 2012)

Thanks for replying.

Did you start a new thread on this? If yes, where is it? I would like to follow the entire adventure


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## DDDvvv (Apr 2, 2012)

anything to do with vfd's will be on this thread. sorry for the long silence. i need to really keep up with this thread.


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## aeroscott (Jan 5, 2008)

I've been googling around to find out what would be needed for testing diy vfd 's running 2 or more at the same time at different speeds ( stability control and differential ) . Can some one help me with a link . I have a signal generator , 4 wire ohm meter , 2 frequency counter/timers (BCD output to computer ) , 50 Mhz hp scope 2 chanel (no BCD) not working right so looking for digital with BCD, , Elenco LCR-1801 , clamp meter dc etc. Looking at freeware to load tests to computer .


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## Stiive (Nov 22, 2008)

aeroscott said:


> I've been googling around to find out what would be needed for testing diy vfd 's running 2 or more at the same time at different speeds ( stability control and differential )


You would need two (or more) motors and two (or more) controllers.
What exactly are you trying to test?


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## aeroscott (Jan 5, 2008)

I have Prius motors , m1,m2 2 each plus a few 3 phase induction motors of various sizes , generators to 150 hp as possible dynos . 10 or so industrial vfd's small to 40 hp , 24 igbts 600a 1200v , 6 igbts 1000a 1200v, lots of big caps , etc . Prime interest is to set up test equipment to check / hack or build drives for 4 motor 4 wheel drive E class benz wagon and other simpler but more important projects like solar panel controller , battery charger , air conditioning , water pump , chain saw etc. I will pick the most simple projects to start with but continue collecting parts fore the most complex projects . I don't want to smoke parts . So I figured a power analyzer ($15,000 ) was not in the cards but I might find one cheep .So I know I can emulate one . So put together hall effect amp meters signal generators , counter/timers , scope etc . Putting all this information onto a computer , I hope will be manageable . Then I could look over the data during /after the run .


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## DDDvvv (Apr 2, 2012)

my latest acquisition: same 1336 drive but this is a 100 hp 480v class. works good but weighs 140 lb.

no electronic mods required. i just need to crack the whip on this bad boy while its running on a treadmill. thats too much weight for a controller.

let the fat trimming begin. target; 40lb


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## Nathan219 (May 18, 2010)

Where does he get such wonderful toys! Nice find a drive ratted for 100 hp continuous should be good for 150hp burst at least.


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## DDDvvv (Apr 2, 2012)

100hp constant torque rated
125hp variable torque
150 % of rated current allowed for 1 minute
180 % of rated current allowed for 10 seconds
200 % instantaneous current allowed
220 % hardware limit ( bus fuse will blow).
400 amp 1200 volts igbt modules
650v dc bus voltage nominal
400v dc undervoltage trip
810v dc overvoltage trip
0 - 400 hz adjustable frequency
0 - 480 v adjustable voltage

i think this will be more than adequate for driving a 25 horses nominal motor.


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## aeroscott (Jan 5, 2008)

I have a very similar unit but lower power 40 hp I think a second unit I striped the parts ( missing the caps) . The point is the case, cooling fins and fan are very heavy at least 1/2 the weight . So with a liquid heat exchanger (box) and alu case it will be much lighter and a little smaller .


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## DDDvvv (Apr 2, 2012)

yes. case weighs 60 lb, but it has the big heavy dc choke. heatsink is 29 lb, and im considering a 10 lb flat plate aluminum, same size, for modding to liquid cooling.


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## DDDvvv (Apr 2, 2012)

busy day today..

first, made sure drive works like its supposed to. took half the day to find out that the precharge board was faulty. (no wonder drive was so affordable) unplugged it, hooked up my own rectifier/precharge system, then motor, and drive works great. 

View attachment 13560


then began the teardown and cleaning;

View attachment 13561


View attachment 13562


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## DDDvvv (Apr 2, 2012)

shripped it down all the way to the bare case. this assembly ; chassis, dc choke, connectors weighs around 60 lb

this is all i need out of the chassis assembly, after lots of cutting, cleaning and assembly;









and this is the finished product. coming in at 61 lb, and half the size of the original drive. now i can carry it around easily, and it fits in the hood/trunk of my conversion.

i kept the 30lb heat sink, but not before i imaged a template of all the screws/holes on it, for a liquid cooled heat sink idea later down the road.


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## subcooledheatpump (Mar 5, 2012)

Nice, does the drive have torque mode?


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## DDDvvv (Apr 2, 2012)

after much research at allen bradley tech documents, i finally found this statement "......... since the 1336s drive does not support torque mode .............."

it will be hooked up with a motor encoder, so thats no big issue for me.


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## DDDvvv (Apr 2, 2012)

just another little update**

i finally figured out how to lower the voltage on this drive. went down all the way to 100 vdc. its a simple solution, i cannot beleive that it took me this long to form in my head.

i was not looking forward to sourcing/buying/installing a 650 vdc battery pack. will detail the procedure once i figure out how to draw diagrams.


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## bennettdan (Sep 20, 2007)

I am very interested in your project. I have a question for you could you tell me the part # of the IGBT out of the first two 1336 AB drives I am also looking to convert one?


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## DDDvvv (Apr 2, 2012)

if you mean the original device, its a 6mb130-e or something. theres an image of it on page 2 of this same thread.

its great to see someone trying out this project. but i abandoned the idea of converting a 3hp drive, and went for a 100hp drive instead. its waaay easier to convert, and everything is already built to handle the high power.

ill be glad to help.


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## flyn_brian (Oct 21, 2012)

DDDvvv said:


> just another little update**
> 
> i finally figured out how to lower the voltage on this drive. went down all the way to 100 vdc. its a simple solution, i cannot beleive that it took me this long to form in my head.
> 
> i was not looking forward to sourcing/buying/installing a 650 vdc battery pack. will detail the procedure once i figure out how to draw diagrams.


Am I missing something here I just read this entire thread and I know that some of these drives will accept Dc current and output 3phase AC current. And I believe the drive you have only accepts 460 VAC 3phase. Please elaborate as to how this feat is being perfomed


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## Coulomb (Apr 22, 2009)

flyn_brian said:


> Am I missing something here I just read this entire thread and I know that some of these drives will accept Dc current and output 3phase AC current. And I believe the drive you have only accepts 460 VAC 3phase.


Possibly what you're missing is that the electronics always runs from DC. They just rectify the incoming AC to DC. Usually there is even an explicit DC bus so that two or more inverters can share a DC bus, so the regen from one can power another. Even if there is no explicit DC bus, it's easy enough to connect after the rectifier, or even just connect to the AC terminals (pick any two), and suffer the slight voltage drop across the rectifier.

In other words, all industrial inverters / VFDs can run from DC, though a few are a little less convenient than others for this.


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## flyn_brian (Oct 21, 2012)

Thank you for clearing that up. Currently I own a Lenze AC Tech SCF 3phase VFD. The lowest possible input voltage I could run to this drive is 208 single phase AC. What would it take in DC voltage to run this drive?


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## Coulomb (Apr 22, 2009)

flyn_brian said:


> The lowest possible input voltage I could run to this drive is 208 single phase AC. What would it take in DC voltage to run this drive?


From the manual, the AC input tolerance is +10% and -15%. So for minimum pack voltage, you would set parameter 01 to say it's getting 208 VAC, and you probably need to keep the DC bus voltage above (208 * (1-0.15) * 1.414) = 250 VDC. There is likely a "low line voltage trip" or similar if the bus goes below this value. So you could use say 100 lithium cells, if you thought you could prevent them from sagging below 2.5 VPC; they would run around 3.35 PVC soon after charging, which would be about 335 VDC max, and 3.2 x 100 = 320 V nominal. 208 * (1 + 0.10) * 1.414 = 323.5; with rectifier losses that would be about 323 V. This is a bit tight; whether you would be getting overvoltage trips with 100 cells or not is unclear. So you might have to run with say 322/3.4 = 95 cells, and not let the cells sag below 250/95 = 2.63 VPC (average).

Whether or not you will have DC but trips really depends on whether the trips are set right to the specifications or not. The manual doesn't seem to give the actual limits. Often, the trip limits are pretty generous. Note that the capacitors must be able to take 240 * (1+0.10) * 1.414 = 373 V, so the overvoltage limit may be that high, or it may needlessly be lower.

If you really wanted to run a lower voltage than 250 V under sag, you could possibly find the voltage divider where it senses the DC bus, and either adjust the ratio higher or lower, or even compress the range by adding in some current from a constant voltage source like the 15 V rail.
You could even just ignore the actual DC bus voltage, and feed it what it's expecting (so it looks like exactly 209 VAC, for example). I suppose the overvoltage trip is actually somewhat useful, so adjusting the ratio such that 375 V measures as the high DC bus trip voltage yet 2.5 VPC (or whatever is realistic for your cells) doesn't trip undervoltage would probably be the most sensible way. Note that for an industrial controller, tripping off is a conservative, safe thing to do. Tripping off while driving is not necessarily conservative or safe, so you should not use these trips as your undervoltage protection of your cells. Have something else emit an alarm or cut back on power well before the drive trips off.

As long as you stay under about 375 V on the DC bus, all should be well, and you don't need the drive to tell you that your non-existent mains is out of spec.


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## Siwastaja (Aug 1, 2012)

Note that some old VFDs may use traditional transformers to make some low voltages for control. In that case, they need to be replaced by small switch mode power supplies of the same voltage; those run from DC, too.


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## PStechPaul (May 1, 2012)

Also, some large VFDs may have SCRs in place of diodes as the input bridge rectifier, which are phase fired to limit inrush current on the link capacitors. If you apply DC to the AC input, the SCRs will latch on and inrush current may be excessive. Thus a precharge resistor may be a good idea.
http://literature.rockwellautomation.com/idc/groups/literature/documents/wp/drives-wp014_-en-p.pdf


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## flyn_brian (Oct 21, 2012)

Coulomb said:


> Possibly what you're missing is that the electronics always runs from DC. They just rectify the incoming AC to DC. Usually there is even an explicit DC bus so that two or more inverters can share a DC bus, so the regen from one can power another. Even if there is no explicit DC bus, it's easy enough to connect after the rectifier, or even just connect to the AC terminals (pick any two), and suffer the slight voltage drop across the rectifier.
> 
> In other words, all industrial inverters / VFDs can run from DC, though a few are a little less convenient than others for this.


So If I open the drive which I haven't done just yet I should be able to connect DC after the rectifier. (I assume there would be a bridge rectifier). Also as said being a rectifier there would be a drop in voltage although not much it would mean less lithium cells. I think as an experiment I should try to get this drive working off DC and then keep my eyes pealed to get a much more stout drive. My vision is to get a drive to at least power a 15 hp motor. While I believe I could build a capacitor bank and put in some larger IGBT's I think it might be money ahead to find a larger drive that already has the capacity to run a larger motor.


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## flyn_brian (Oct 21, 2012)

PStechPaul said:


> Also, some large VFDs may have SCRs in place of diodes as the input bridge rectifier, which are phase fired to limit inrush current on the link capacitors. If you apply DC to the AC input, the SCRs will latch on and inrush current may be excessive. Thus a precharge resistor may be a good idea.
> http://literature.rockwellautomation.com/idc/groups/literature/documents/wp/drives-wp014_-en-p.pdf


Thank you for the info. The more I learn, the more I realize I need to learn and how much I have forgotten.


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## DDDvvv (Apr 2, 2012)

Ok, i promised to outline the procedure for reducing the battery voltage for a 480vdc class vfd.

this info pertains to my particular drive, an allen bradley 1336 plus, model 1336s-b100, a 100 hp drive.

please take the info as it is, dont ask me questions about a diferent drive, coz i dont know.

ok here's the block schematic from the troubleshooting guide:








thats all you get from this drive. i've added some highlights onto the image.

i gave up on hunting for the voltage dividers, because they are enclosed in a module of some sort, then the module sends the voltage info through a i2c or spi bus to the main controller ic. this is after pin 25 and 27 highlighted in pink

next step was to try feed it with the 24v aux input. only problem with that is, the gate drivers requre a high voltage input voltage; 650vdc for the drive to fire the gate drivers. those are the power inputs circled with red. another dead end.

so, there's only one option left, the main feed from the bus caps, circled in yellow. this two lines power everything else on the drive.

the trick is to disconnect the two wires circled with yellow from the bus capacitors, feed them with the high voltage that the gate/control board is expecting, and feed the bus caps, with whatever low voltage you want.

so, disconnect power leads to gate driver board, feed it with the high voltage its expecting, from a boost converter, feed the main bus with the lower voltage you want, and enjoy!

on my next post, ill show how to get a very affordable boost converter, that will accept 90-350vdc, and output around 540vdc, to feed to the gate driver board.


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## Coulomb (Apr 22, 2009)

DDDvvv said:


> i gave up on hunting for the voltage dividers, because they are enclosed in a module of some sort, then the module sends the voltage info through a i2c or spi bus to the main controller ic. this is after pin 25 and 27 highlighted in pink


Surely they don't have 650 VDC on that compact connector to the main board, J1. I would expect those signals to be already divided down.



> only problem with that is, the gate drivers require a high voltage input voltage; 650vdc for the drive to fire the gate drivers. those are the power inputs circled with red. another dead end.


That doesn't sound right.

I'm possibly not following everything here, but I suspect you haven't cracked it just yet.

I'm sure you realise that by providing some 1/6th (17%) of the rated DC bus voltage, you will get only about 17% of rated power, because the current capacity of the IGBTs doesn't increase to compensate for the lower voltage.

Interesting project though; I read with interest.


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## subcooledheatpump (Mar 5, 2012)

Maybe he means the gate driver board needs 600V+ to start the gate driver power supply. In other words run the switching power supply that runs basically the whole drive with a boost converter, then hook whatever to the capacitor bank. Older drives actually used to have the inverter and control power supply seperate, so you could do just this without any real modification. 

Only thing I see is what Coulomb pointed out, less voltage means less power for the same current. Still interesting though, as this allows for the batteries in the EV to run down very low while still being able to run the drive


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## DDDvvv (Apr 2, 2012)

sorry about the misunderstanding. i meant the gate drive power supply needing the high voltage supply to operate.

yes, i understand that the output power level is reduced, by lowering the supply voltage on this drive. by specifying the 100v low voltage, i was just experimenting with the lowest limits. i was not saying that i plan on using a 100v batt pack.

remember, once again, this is just an experiment. im hoping that this will open some more avenues, like swapping the current sensors, with double the rating, to increase the current to the motor, or simplify the use of a boost converter, like a prius system. i currently own a 208v prius battery pack from a local junkyard, and this is my experimental pack in this project. 

i drew up a couple of diagrams for those of us who still dont understand.

here's the internal block connection in this drive:









and here's the mods that i made to the drive:









the output igbt modules receive the lower voltage, the gate driver/control boards do not know, that, and they are happy, since they are receiving their regular voltage.


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## abelenkiy (May 25, 2012)

Hi, i have finally caught up to the thread. Awesome work. I just got inspired and ordered a few vfds from ebay. Do you by any chance have a link or idea mentioned for the boost circuit?

Thank you
Alex Belenkiy


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## Arlo (Dec 27, 2009)

Great thread guys.


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## DDDvvv (Apr 2, 2012)

Its been a long time since I updated this thread. Ive been busy with the design of a hv battery charger, which is nearIng completion.

Ok, boost converter: there's two choices. Design and make one, or modify one from a power supply to suit your needs.

I decided to go with option 2. Modify a ready made one. 









Here's the power supply to be modified. Its a dell dps-500cb server power supply. I think its used in their 2650 poweredge servers. Lots of them on ebay fo around $9. It outputs 12vdc at 42 amps, with a input voltage range of 100-240v ac. I will outline the procedure to use this very same supply as a 12vdc converter for ev applications at a later date.









Here's the power supply opened up. Its divided into two boards. Top board is the pfc circuit and bottom board is the power supply.









We are just interested with the pfc board. From my tests, it will take 95vdc to 350vdc and any voltage in between, and convert it to 403vdc. The interesting thing about it is that its always powered on, and is independent of the main low voltage flyback converter.









Here's the main capacitor, inductor and heatsink with diode and boost mosfet.

And here's the circuit traces showing the voltage divider we are interested in.









Of interest is R806-R822 and the smd resistors between, on thebunderside of the pfc pcb. These two sets of resistor dividers feed power to the pfc controller ic, a uc3854 and feed a 7.5v reference pin in the same ic. They feed from the pfc 403vdc positive output , and are used to regulate the output voltage. This is what needs to be modified.

After some calculations, I figured out that I could change the output from 403vdc to 540vdc by the addition of one resistor. A 100K ohm 1/4 watt resistor.









I cut the trace that feeds the voltage divider array, and added the 100k resistor. So when powered on, the controller ic will see a lower voltage on the v-divider, and will increase pwm duty to regulate voltage output to the setpoint, thus increasing output voltage.









Here it is, dishing out 536vdc. Remember, the 330uf 450v main cap has to be replaced. It wont handle the higher voltage. I replaced it with 2 680uf 450v caps wired in series.

I tried powering the vfd with the original 403vdc, and it never powered up. It is comfortable with 536vdc. 650vdc ic the nominal dc supply voltage required by the vfd.

I'm afraid of going higher than 540vdc since the pfc boost diode, mosfet, and aux power supply components (pfc board has a small flyback that provides standby power to main flyback) are rated for 600v. 540v is in the lower range for this vfd, but its regulated, and is only used to power the gate drive/control board.


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## PStechPaul (May 1, 2012)

Very interesting and informative. How much current will the PFC section produce at 540 VDC? I assume it matches the 500W power rating, so probably about 1 amp? Does it also provide this much with a boost from 170-180 VDC? I have a 7.5 HP 460V VFD I'd like to use on a 5 HP motor for a tractor, but I'd rather not have a 500 VDC battery pack which would be 42 x 12V12Ah SLAs. Much better if I could use 15 in series for 180 VDC. The 2.2 kWh would be OK since I would only need about 1-2 HP continuously and 5 HP occasionally, and 1 hour run time is fine. I figure I could use four of these in parallel for 2000W?

Do you have a link to these supplies on eBay? Thanks! 

OK, found some: http://www.ebay.com/itm/500W-Dell-P...pply-DPS-500CB-2650-J1540-0H694-/221170785782

$13 with free shipping. Others are cheaper but like $20 shipping.

Another good deal:
http://www.ebay.com/itm/Lot-of-2-Dell-Poweredge-2650-Power-Supply-DPS-500CB-J1540-/271156387614


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## DDDvvv (Apr 2, 2012)

I haven't done any current tests on the pfc converter. It should correspond to 500 watts. The gate drive board im powering up only requires 0.4 amps, so the original output current is more than adequate.

Power from the device is supposed to be lower, if using 120vac. The full power of 502watts is available if using 240vac.

There's a app note for this pfc controller ic, that I was studying, and it states that by changing a couple of resistors, and increasing the sense resistor wattage, output current can be increased. You could jack up the current, but that would mean switching all the power devices, and reinforcing the traces.

The parallel idea sounds good, but isolate each output with a diode, before linking all the outputs together. This way, the individual sense circuits dont get confused from the different voltages, however small they are.

There are lots of stronger power supplies out there. The dps-1670 will output 1670 watts , but the pfc and flyback share the same board. I would do some research first, if powering a vfd with it.

Its cheaper to buy two, on ebay, instead of one.


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## subcooledheatpump (Mar 5, 2012)

Very nicely done mod with the boost PFC. I'd be pretty sure it would be able to run just the gate drivers. If it came down to it, you could add more capacitance to the gate driver power supplies. I'd be more concerned about the voltage regulation of the boost PFC during regen, specifically the speed at which it can adjust the inductors pulse width. If that works fast enough I'd say you've cracked it


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## abelenkiy (May 25, 2012)

Wow!!! Where were you a year ago, i could have salvaged 30+ HP server power supplies 
So basically i can parrallel a bunch of these to allow me a much higher combined current.
Or copy and recreate the circuit using higher components to begin with.
A few dumb questions:
Do you know how much loss is involved per unit?
If tied together using diodes, how will regen work.

Thank you
Alex Belenkiy


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## DDDvvv (Apr 2, 2012)

The mod that I performed was aimed at powering only the gate drive board and control board. Not the whole vfd , including the power devices. Because its not powering the controller output igbt's, it will not see any high regen voltage. Just the full battery voltage, which will receive a controlled regulated regen voltage, (im working on that).

I have no idea about paralleling a bunch of this pfc converters. If I was making a powerful boost converter, I would probably make a single big one, or a pair.

Hopefully, someone can verify that by experimenting. Regen energy will be a pain, if going down this route. The power components in this pfc board are 600v 15 amp devices. So if your motor regenerates anything over 600v, component damage might occur.

Efficiency is about 87%. I used to have a datasheet of this power supply in one of my computers, I cant seem to find the datasheet, even on the web.


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## NintendoKD (Apr 29, 2012)

just reading through your thread, I am very interested. I want to build a high voltage version vfd, at 1200v or 2400v the current necessary would be much lower and the motor would be more efficient, but what kind of starin would that put on the driver circuit? I was looking at using hyperfast diodes in the readymade vfd's like this one:
http://galaxyic.en.alibaba.com/prod...0/IC_RHRG30120_30A_1200V_Hyperfast_Diode.html


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## DDDvvv (Apr 2, 2012)

1200v? 2400v  .You will probably have problems sourcing parts that can withstand that kind of voltage.

Then the motor insulation might cause hell in this kind of voltages. But thats just my opinion.
If you are interested in higher voltages, may I suggest a 575 vac class vfd (805vdc on dc bus), at the power rating that you desire. This way, you have the safety guards already inbuilt, and you don't need to play around with modifying the gate drivers.

And industrial motors are available, that match the 575v vfds

Then there's the pain of sourcing that kind of voltage, from a battery pack or a boost converter.........

Be prepared to jump through a lot of hoops, even for the 575v class system


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## subcooledheatpump (Mar 5, 2012)

I would agree 575 volt systems may be more of a pain, 480 volt systems are the most popular, you'll find tons of 480 volt motors and drives around the internet and surplus stores. Most 480 volt drive can go up to 700 volts without a problem, some can go up to 750 without problems


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## NintendoKD (Apr 29, 2012)

I didn't mean to hijack the thread here. Just trying to contribute. The insulation used on the coils in the motor is no different than insulation in let's say a HVT, like a MOT right? the motor will run cooler as the higher voltage will not allow current buildup in the coils while under load "normally the load is applied to the rotor and coils in lower voltages, the lower the voltage the higher load is placed on the coils..... to a point" In laymans terms this means lower operating temps in the motor, making the effective run time of the motor longer as the insulation won't be under strain. I thought we were talking about using an industrial motor here? they are built to the teeth, like a tank even. I don't think it will be that hard to source HV components, but you may have to shop around and won't be able to get them all from the same source, no one-stop-shopping. besides the high voltage is produced from the component so as long as there is nothing after it in the circuit then there shouldn't be a problem right? the pack voltage can be kept relatively low, you don't need 1200-2400vdc to make 1200-2400vac, just as long as you have the necessary current and pack voltage "120 vdc, @X amps to supply the inverter circuit buss. Realistically the current necessary to drive the buss will be effectively higher, but that shouldn't be a problem right? Maybe I'm just a novice here. Shoot, I don't even have a degree, what the hell do I know. Like I said, just wanted to try and contribute is all. I could only hope that any idea could be useful, even if it is a little unconventional. I love this forum, you guys are the best. I can't wait to see the final deal. I personally think that open source is the way to go. BTW, what I don't know is what would the final drive frequency be for your setup?


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## subcooledheatpump (Mar 5, 2012)

Yes the currents are lower, but the wires are smaller and there are more of them packed into a smaller space, so the heat is relatively the same. 

Because of this, high voltage motors are more efficient to an extent, but it may not be worth the time and money to invest in a higher voltage motor and drive. That is really your choice. You also need a boost converter, which can help when the battery voltage changes, but it also adds losses. So it's all in what you want to do, but for industrial, the most common, cheapest and easiest is a 480 volt system.


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## cts_casemod (Aug 23, 2012)

subcooledheatpump said:


> Yes the currents are lower, but the wires are smaller and there are more of them packed into a smaller space, so the heat is relatively the same.
> 
> Because of this, high voltage motors are more efficient to an extent, but it may not be worth the time and money to invest in a higher voltage motor and drive. That is really your choice. You also need a boost converter, which can help when the battery voltage changes, but it also adds losses. So it's all in what you want to do, but for industrial, the most common, cheapest and easiest is a 480 volt system.


 
You could use the PFC controller would be as a battery charger. I thought about that before but wasnt to worried to study it. You could charge a pack of 96 LiFEPO4 cells quite easily at 320V or even 640V with a 320-0-320 Configuration, fully PFC corrected.

I have one of those PS and might play with it. 4 PS would give a 2KW Charger for 40$, even cheaper than my 97% efficient Capacitive charger 

On this particular model the 500Watt rating is valid for both 115 or 230V. In fact the PFC section can handle 650W maximun for a few minutes. If there is enought interest I might open a topic about this.

As for the VFD I am in the same boat. Its quite hard to find something decent with FOC/torque vector. I opened a topic with some of the solutions I plan to try to improve my motor efficiency at low loads and low speeds.

One of the losses comes from torque boost. I need that when the car starts to roll, however after its rolling its just an extra voltage to the motor, wasted as heat say, when I am slowly driving in traffic. 
So the idea is to both implement a slip controll and a dynamic voltage adjustment.

Other loss comes from the motor being energized when no or little torque is being requested, again resistive losses when I could, say, be going downhill not using any power. It would be so much more efficient to let the motor freewheel on this conditions and activate regeneration for a short time as we do with the hydraulic brakes or allow it to resume operation from that rotation (that the encoder was reading) when extra power was required. I believe this is one or the gaps between AC and DC and DC clearly wins on this case. 


Its not really hard to syncronize an induction motor. As long as the frequency is the same the slip takes care of the rest unlike a syncronous motor


It would be nice if all the members that moded a VFD could participate on this topic and give sugestions


http://www.diyelectriccar.com/forums/showthread.php/ac-induction-motor-control-algoritm-84471.html


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## NintendoKD (Apr 29, 2012)

I do hope I didn't kill and bury this thread, good stuff here.


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## cts_casemod (Aug 23, 2012)

NintendoKD said:


> I didn't mean to hijack the thread here. Just trying to contribute. The insulation used on the coils in the motor is no different than insulation in let's say a HVT, like a MOT right? the motor will run cooler as the higher voltage will not allow current buildup in the coils while under load "normally the load is applied to the rotor and coils in lower voltages, the lower the voltage the higher load is placed on the coils..... to a point" In laymans terms this means lower operating temps in the motor, making the effective run time of the motor longer as the insulation won't be under strain. I thought we were talking about using an industrial motor here? they are built to the teeth, like a tank even. I don't think it will be that hard to source HV components, but you may have to shop around and won't be able to get them all from the same source, no one-stop-shopping. besides the high voltage is produced from the component so as long as there is nothing after it in the circuit then there shouldn't be a problem right? the pack voltage can be kept relatively low, you don't need 1200-2400vdc to make 1200-2400vac, just as long as you have the necessary current and pack voltage "120 vdc, @X amps to supply the inverter circuit buss. Realistically the current necessary to drive the buss will be effectively higher, but that shouldn't be a problem right? Maybe I'm just a novice here. Shoot, I don't even have a degree, what the hell do I know. Like I said, just wanted to try and contribute is all. I could only hope that any idea could be useful, even if it is a little unconventional. I love this forum, you guys are the best. I can't wait to see the final deal. I personally think that open source is the way to go. BTW, what I don't know is what would the final drive frequency be for your setup?


Let me just clarify a few points here: Although the current decreases the resistance on a higher voltage motor is higher so the losses remain constant. (PLoss =R*I^2) You may have a bit higher efficiency in the cabling/controller/battery but there is a premium for using contactors/cables and other equipment rated for high DC Voltages (ask me how I know). 

Where you really may win is by driving a low voltage motor with higher voltage, since it will continue to provide torque to a higer rpm. Say a 1440RPM 208V AC motor, being driven with 415VAC will provide nominal torque up to 2900RPM, hence doubling the horsepower. Of course this is valid in any motor, DC or AC, hence many conversions use 48V DC motors with 96 or 120V packs. The motor provides the same exact torque as with 48V but to a higher RPM. (HP = Torque * RPM)

415VAC = 600VDC - A 690VAC contactor will not work with 600VDC.

Sure, as you pointed, you can use a lower voltage battery pack and some kind of booster integrated into the motor controller. This will solve the high voltage problems at the source, but it is another source of inefficiency/weight and the complexity increases if regeneration is required.

I have been interested in using one myself, but have never found no one using one. Prius uses such system, but it is not documented enough to be used in our conversions.

Anyway moral of the history is higher voltage is not really a benefit in other that to allow a regular 415VAC motor to be used, however the costs of doing this can be the same or higher than getting a rewinded motor to, say 104V.

PS: 
Most American 12 lead motors can be run at 104V @ 60Hz without modifications.
12 Lead European motors can be run at 200-240VAC @ 50Hz without modifications. 

Same applies if you open a conventional 6 wire motor and are able to find the 6 individual coils (4 Pole motors)


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## epyon (Mar 20, 2008)

if you ever want a test car , I'm in . P.M me when ever . I'll send money for parts and beer


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