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Old 03-11-2014, 05:29 PM   #6282 (permalink)
MPaulHolmes's Avatar
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,832

Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
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Oh ya it wouldn't be a secret. I would open source that little bugger. The power section isn't anything terribly original. The purpose in life of a SBE capacitor is to be connected to half bridge igbts with copper sheets. Read any datasheet on how to reduce stray inductance in an inverter, and they'll show you 2 copper sheets to connect the igbts with the capacitor.

I would just want to make sure it works before posting things on the wiki. I sometimes get emails about a board on the wiki that I don't even remember making. haha.

One reason I wanted to match the turn on and turn off times so perfectly was so I could just use a current sensor on one of the igbts for torque control of the motor. Maybe I could have a current sensor on each of the 3 igbts, and then if the hardware overcurrent ever trips on any of the 3 (perhaps indicating that one is turning on before the others, and getting excessive current through it), then the end user could tweak the delays until that doesn't happen anymore. Oh no, igbt 1 got too much current. increment igbt 1 turn-on delay by 1 femtosecond LOL. save. done! boom shakalaka. That would add around $52 to the cost (2 current sensors), but for a prototype it wouldn't be bad to make it as bulletproof as possible.

My last project had to precisely and independently control 60 igbts (none were in parallel), so this should be a walk in the park! 3!? lame! haha.

I'll get a bill of materials together and see what everything costs.
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