Heh, it's interesting that you found this thread. I have had your website bookmarked for a long time. Yeah, I've now blown up the controller twice. I think this makes my average about 60% since I've successfully tested with no blow ups like three times and blown it up twice. Luckily this last time was just a transistor, gate resistor, and a few diodes. I'm using $25 surplus 200A IGBTs right now so that explosions are less sad.
Here's my thoughts on my last blow up (which I unfortunately did not film at all.... stupid!):
I ordered a 50A 800V three phase rectifier off of ebay and used it connected to 240V single phase as my power source. Since I had precharge capacitors installed they were able to smooth the voltage to about 339V at rest. Unfortunately I never got to testing how much voltage fluctuation I was getting. However, I was only testing a 2HP motor unloaded so I doubt that the amperage was too high. I did have an oscilloscope running at the time. I put a probe on one of the three phase outputs to the motor while testing. I could see really large spikes on the output. They looked very short, perhaps like 1us. Here is where I wish I really wish I had video because all I can go on now are vague recollections after the fact. I'm not sure if the spikes were because A. I somehow managed to use IGBTs with no freewheel diodes. I doubt this because any reasonable half bridge should have them but I'll check B. using a rectifier would have caused the input voltage to be very unstiff and maybe that caused some issues C. I had way too long of a connection between the capacitor bank and the bus bars. I knew that was naughty but was hoping to get away with it. One thing is sure though, I had way too much inductance on the input side of the controller. D: Maybe my leads from driver to IGBT are too long. I mean, the wires are like 2.5" or something but maybe that's still too much. Or maybe something was getting induced on the lines. I might be able to shorten the leads even more.
Regrettably I didn't test for many of my guesses above. It blew up before I could.
Well, it's fixed again and I'll keep at it.
Quote:
Originally Posted by etischer
Your first spin video is just like mine =) I blew up my IGBTs too =)
<<URL removed>>
Now, two years later, I'm running closed loop vector control, and have racked up almost 30k miles!
It's great to see other people take on a such a project. I wish you luck.
Here's a link to my inverter project: <<URL removed>>
It's my first post, and I'm not allowed to post URLs yet =( You can google etischer and find my electric vehicle webpage.
Cheers
-Eric.
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