Improve power stage design, use planar DC bus, put closer modules, ddd snubbers and it shuld live much longer 
Building a 3 phase controller (Maybe)
Long Post, you have been warned.....
Some of you might remember this thread and for some back round it might be helpful to look over it briefly:
http://www.diyelectriccar.com/forums/showthread.php/diy-ac-motor-controller-super-size-30075.html
Others no doubt are aware of my own personal issues with the BLDC motor controller for my car which has died a second time roughly 2000 km after I brought it back to life from a mild internal fire last winter. See my build thread for details on that saga......
So far I can't quite figure out what is wrong with it this time and I am beginning to wonder if its worth bothering to fix it a second time even if I could. Options I am exploring right now are to try and replace the logic/driver board with an evaluation board but I am not quite sure which one to use.
The biggest stumbling block is finding one that I am sure can control an external driver since most appear to be intended for powering fractional horsepower inverters and are fully integrated with their own built in power stage - which is naturally way too small to push a 3000lb car up to highway speed. I'm wondering if they could be modified to run an external power stage but I'm not sure if it's worth doing this. Opinions wanted!
Of some of the things I found in the process, this was fairly interesting:
http://www.eefocus.com/设计我最赞/blog/08-09/155607_39e2c.html
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The ideas in that link could solve my problem for how to drive my existing IGBTs since I *think* the powerex BG2B-5015 units can run the IGBTs I already have. Some reorganizing inside the controller would be needed to physically fit them though. At roughly $100 each, they aren't cheap but it would get me running again and digikey does carry them.
Problem is I would still need a logic board to control the inverter. They show that too in the link, but they also had to modify an existing MCU developer board a few times before they could settle on something......I'm not sure if I could pull something like that off yet.
This board seems to have most of what I'm after since they claim it can run an external power stage, but finding a source proved challenging:
http://www.fujitsu.com/ca/en/servic...microcontrollers/datalib/devtools/91f267.html
And again, I'm still not sure if other boards that come with low power integrated power stage can be modified to drive an external power stage. Gaps in my knowledge are rather annoying in that area.
I stumbled over these during my research when a link showed up on an ecomodder discussion that google found for me:
http://www.ehitex.de/p_info.php?products_id=544&xID=574668e34207918b45cdf663e9e9cd2b
It's extremely unlikely that I am going to dish out that kind of money at this point but I did find the price to be fairly reasonable considering the 80kw power rating. I have looked over the PDF file here:
http://www.infineon.com/dgdl/AN+Hyb...47094&fileId=db3a30432239cccd01225a7cfb166c8a
and its not exactly plug & play, but all the major hardware is there. Most of the work appears to be in setting up the software to run the motor safely. I have to admire the compact and clean package layout (water cooled).
A smaller 30kw version is available here:
http://www.ehitex.de/p_info.php?products_id=543&xID=574668e34207918b45cdf663e9e9cd2b
The HybridKIT1 and 2 are built on the idea of an integrated single piece 3 phase IGBT power stage, and if you looked more closely in the AC motor thread I posted at the top, Technologic found a similar setup offered by Fuji. It would be nice, but I'm not particularly picky at this point.
Applied Power Systems in the USA does offer an impressive IGBT half and full bridge driver board that is rated for IGBTs up to 1700 amps. Not that I need that much but there seems to be a wide gap in the products I have been able to find with most being under rated for what I need.
http://www.appliedps.com/drivercircuits.htm
No, I haven't called and asked for a price yet, but I probably don't want to know anyway. Besides, that would still be only half the battle and I would still need a motor control logic board.
The general idea I am working on at the moment is to get a basic control setup together that could get the car running again but that could also be reused in the future if I decide to upgrade the power stage.
I haven't quite given up 100% on repairing the current setup, but after the second failure I felt compelled to try putting together a backup.
Some of you might remember this thread and for some back round it might be helpful to look over it briefly:
http://www.diyelectriccar.com/forums/showthread.php/diy-ac-motor-controller-super-size-30075.html
Others no doubt are aware of my own personal issues with the BLDC motor controller for my car which has died a second time roughly 2000 km after I brought it back to life from a mild internal fire last winter. See my build thread for details on that saga......
So far I can't quite figure out what is wrong with it this time and I am beginning to wonder if its worth bothering to fix it a second time even if I could. Options I am exploring right now are to try and replace the logic/driver board with an evaluation board but I am not quite sure which one to use.
The biggest stumbling block is finding one that I am sure can control an external driver since most appear to be intended for powering fractional horsepower inverters and are fully integrated with their own built in power stage - which is naturally way too small to push a 3000lb car up to highway speed. I'm wondering if they could be modified to run an external power stage but I'm not sure if it's worth doing this. Opinions wanted!
Of some of the things I found in the process, this was fairly interesting:
http://www.eefocus.com/设计我最赞/blog/08-09/155607_39e2c.html
The ideas in that link could solve my problem for how to drive my existing IGBTs since I *think* the powerex BG2B-5015 units can run the IGBTs I already have. Some reorganizing inside the controller would be needed to physically fit them though. At roughly $100 each, they aren't cheap but it would get me running again and digikey does carry them.
Problem is I would still need a logic board to control the inverter. They show that too in the link, but they also had to modify an existing MCU developer board a few times before they could settle on something......I'm not sure if I could pull something like that off yet.
This board seems to have most of what I'm after since they claim it can run an external power stage, but finding a source proved challenging:
http://www.fujitsu.com/ca/en/servic...microcontrollers/datalib/devtools/91f267.html
And again, I'm still not sure if other boards that come with low power integrated power stage can be modified to drive an external power stage. Gaps in my knowledge are rather annoying in that area.
I stumbled over these during my research when a link showed up on an ecomodder discussion that google found for me:
http://www.ehitex.de/p_info.php?products_id=544&xID=574668e34207918b45cdf663e9e9cd2b
It's extremely unlikely that I am going to dish out that kind of money at this point but I did find the price to be fairly reasonable considering the 80kw power rating. I have looked over the PDF file here:
http://www.infineon.com/dgdl/AN+Hyb...47094&fileId=db3a30432239cccd01225a7cfb166c8a
and its not exactly plug & play, but all the major hardware is there. Most of the work appears to be in setting up the software to run the motor safely. I have to admire the compact and clean package layout (water cooled).
A smaller 30kw version is available here:
http://www.ehitex.de/p_info.php?products_id=543&xID=574668e34207918b45cdf663e9e9cd2b
The HybridKIT1 and 2 are built on the idea of an integrated single piece 3 phase IGBT power stage, and if you looked more closely in the AC motor thread I posted at the top, Technologic found a similar setup offered by Fuji. It would be nice, but I'm not particularly picky at this point.
Applied Power Systems in the USA does offer an impressive IGBT half and full bridge driver board that is rated for IGBTs up to 1700 amps. Not that I need that much but there seems to be a wide gap in the products I have been able to find with most being under rated for what I need.
http://www.appliedps.com/drivercircuits.htm
No, I haven't called and asked for a price yet, but I probably don't want to know anyway. Besides, that would still be only half the battle and I would still need a motor control logic board.
The general idea I am working on at the moment is to get a basic control setup together that could get the car running again but that could also be reused in the future if I decide to upgrade the power stage.
I haven't quite given up 100% on repairing the current setup, but after the second failure I felt compelled to try putting together a backup.
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I already have data sheets printed off for the motorolla MC33035 IC and did some reading on that a while back. The main board in my current setup does have what I believe are trim pots on each of the 3 main resistor adjusted feedbacks to the microchip, but I never got the chance to investigate further since I wanted to have some proper meters in the car before I took the risk of adjusting anything.
One thing I was never able to verify is if the chip is capable of offering an effective regenerative braking. I think the three adjustments were for the acceleration, deceleration, and peak current limit. In theory the deceleration constant could affect regen, but the datasheet also mentioned the chip was designed to "coast" the motor if rotor speed exceeded the commanded speed, and the actual brake switch could be dangerous since it's basically uncontrolled and amounts to shorting out the motor.
What's strange is I did observe a fairly powerful electric braking effect when the motor was spun above the normal operating range from driving downhill in a low gear. Although again, I had no way to know if power was really going back into the battery in that instance. I guess I'll never know It felt like hitting a speed governor.
I've seen that line of powerex IPMs and they are very nice. Integrating the gate drive into the IGBT sounds like a great way to simplify everything and improve reliability. Not to mention space savings. 300 amps is a bit low for what I need (currently have 400amp modules) but $400 is a decent price for what it is. Its already getting close to what I would spend on external gate drivers that would be needed for rebuilding my existing setup.....
One thing I was never able to verify is if the chip is capable of offering an effective regenerative braking. I think the three adjustments were for the acceleration, deceleration, and peak current limit. In theory the deceleration constant could affect regen, but the datasheet also mentioned the chip was designed to "coast" the motor if rotor speed exceeded the commanded speed, and the actual brake switch could be dangerous since it's basically uncontrolled and amounts to shorting out the motor.
What's strange is I did observe a fairly powerful electric braking effect when the motor was spun above the normal operating range from driving downhill in a low gear. Although again, I had no way to know if power was really going back into the battery in that instance. I guess I'll never know
It felt like hitting a speed governor.I've seen that line of powerex IPMs and they are very nice. Integrating the gate drive into the IGBT sounds like a great way to simplify everything and improve reliability. Not to mention space savings. 300 amps is a bit low for what I need (currently have 400amp modules) but $400 is a decent price for what it is. Its already getting close to what I would spend on external gate drivers that would be needed for rebuilding my existing setup.....
DS conclusion is correct, and this is not a regenerative braking. After turning on lower transistors, the current circulates through the motor and transistors, dissipating power in their resistances. Fortunately, most controllers allow external PWM control (as a last resort, you can apply APWM directly to brake input pin), and this should allow regeneration: when transistors are on, circulating current rises and stores energy in motor phases leakage inductances, then after switching off, that energy discharges through aniparallel diodes to DC bus.
This is perfectly normal for speeds beyond base speed. BEMF has exceded DC bus voltage and regenerative current has flowed through antiparallel diodes even in the case the transistors have been completely switched off.
See http://en.wikipedia.org/wiki/Brushless_DC_electric_motor#Kv_rating
It was a real regenerative current. Uncontrolled, so it might be dangerous for your controller.Although again, I had no way to know if power was really going back into the battery in that instance. I guess I'll never know
Hmm........
I was already thinking to do that since I can easily make an aluminum liquid cooling setup in our shop.
You are very likely correct. The car struggled to reach 65 MPH and I highly doubt it really needs 50Hp to sustain that speed. I wonder if I was getting around on as little as 20 kw of power? Eventually I should be able to do some comparisons once its running again and I have working meters. Its one of a few questions that kept me up at night.
Although I heard from one source that IGBTs should not be run more than about half their rated capacity so 200 amps would be the safe limit on a 400 amp module. Does that sound right to you?? The infineon spec sheet for the FF400R06KE3 IGBTs states a peak current of 800amps for 1ms. I'm not sure if that means all of the 400 amp rating is safe to use even with adequate snubber protection.
http://www.cntongling.com/guowai/pdf/ff400r06ke3.pdf
How do I know if it gets over amped? It never overheated, but I realize thats not much to go on.
haha, no - and no. But if I need to I will get it. I'm in too deep to back out now so I might as well start looking for the tools.
I agree, but after all thats happened, there doesn't seem to be much choice.
Thanks for your input, it helps a lot.
Its been a few days of reading bits and pieces of various datasheets in my spare time and I'm now 90% sold on getting the dsPICDEM MC1 board:
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en023540
Seems to have everything I could ever want and then some including a brake chopper.
I'm still mulling over what to do about the power stage though. The integrated IPM route is tempting but I would feel bad not to use the IGBTs I have considering the cost of an upgrade.
Of course starting a controller from scratch would allow me to make something much cleaner and more compact. Hopefully more reliable too.
Thinking more about what Weisheimer for power rating of my current controller also has me mulling over if I really need more than 400amp rated units. As it is the car was underpowered but drivable and my best guess is it wasn't putting more than 20kw to the motor. Comparing to other conversions, that power seems about right for a car of this size and weight to sustain reasonable highway speeds. Realistically, my battery pack shouldn't be asked to deliver more than 30kw constant anyway due to the 1C continuous rating (200A cells x 156 system volts = 31.2kw). Peak is 5C for 15 seconds but I'll probably never see that considering the size of controller and motor needed for that. I wonder if 40kw really would be enough.....
Twice the power of what I had would probably come close to breaking traction and make for adequate power. Maybe I can take it snow boarding someday after all..... (a few 12% hills to face on the mountain)
So what do you guys think about the IGBT rating verses the actual controller output? What sort of safety net should there be?
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en023540
Seems to have everything I could ever want and then some including a brake chopper.
I'm still mulling over what to do about the power stage though. The integrated IPM route is tempting but I would feel bad not to use the IGBTs I have considering the cost of an upgrade.
Of course starting a controller from scratch would allow me to make something much cleaner and more compact. Hopefully more reliable too.
Thinking more about what Weisheimer for power rating of my current controller also has me mulling over if I really need more than 400amp rated units. As it is the car was underpowered but drivable and my best guess is it wasn't putting more than 20kw to the motor. Comparing to other conversions, that power seems about right for a car of this size and weight to sustain reasonable highway speeds. Realistically, my battery pack shouldn't be asked to deliver more than 30kw constant anyway due to the 1C continuous rating (200A cells x 156 system volts = 31.2kw). Peak is 5C for 15 seconds but I'll probably never see that considering the size of controller and motor needed for that. I wonder if 40kw really would be enough.....
Twice the power of what I had would probably come close to breaking traction and make for adequate power. Maybe I can take it snow boarding someday after all.....
(a few 12% hills to face on the mountain)So what do you guys think about the IGBT rating verses the actual controller output? What sort of safety net should there be?
You are telling me what I want to hear, thanks!
I never measured temperature direct from the source on the controller but I found that no matter how hard I was able to run the car, the cooling fans never came on unless it was a warm or hot summer day. During a heat wave, they came on just from being switched on and parked in the sun......
I think the fan cycling switch was set for 30C but I'd have to double check that.
Regarding temperature, the hybrid kits by infineon that I linked to earlier claim to be able to run at ICE coolant temperature in order to share the same cooling package. It made me wonder if an inverter like this can be used for heating the interior of the car but I wonder how wise it would be to have the controller that warm all the time. It's tempting because a separate heater does limit an EV's range and it would be a way to increase overall efficiency without sacrificing comfort. I'm getting ahead of myself though.
Either way, I am looking at a water cooled heat sink and a cooler up front in the car.
I never measured temperature direct from the source on the controller but I found that no matter how hard I was able to run the car, the cooling fans never came on unless it was a warm or hot summer day. During a heat wave, they came on just from being switched on and parked in the sun......
I think the fan cycling switch was set for 30C but I'd have to double check that.
Regarding temperature, the hybrid kits by infineon that I linked to earlier claim to be able to run at ICE coolant temperature in order to share the same cooling package. It made me wonder if an inverter like this can be used for heating the interior of the car but I wonder how wise it would be to have the controller that warm all the time. It's tempting because a separate heater does limit an EV's range and it would be a way to increase overall efficiency without sacrificing comfort. I'm getting ahead of myself though.
Either way, I am looking at a water cooled heat sink and a cooler up front in the car.
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