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Old 01-16-2009, 04:08 PM   #224 (permalink)
MPaulHolmes's Avatar
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Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
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Just so I understand:

Drive board is the power section with the mosfets, big capacitors, and big diodes, and control board is the low power stuff, right?

I think that's a great idea. Most controllers I know of sort of intertwine the two because of a DC-DC converter that turns full pack voltage into 12v and 5v for the control board. That's why I went with a 12v battery to power the controller. Full pack voltage becomes completely independent of the control section.

You could literally have 2 boxes! A control board and a power section. There is one thing to consider, though. The 12v output of the PWM signal from the gate driver that goes to the gates of the mosfets must be as short as possible. You could have the 2 halves of the controller sort of snap together making the connection.

The control board gets 12v power from the car's auxiliary battery that powers lights and blinkers and stuff. There's a 12v-12v isolated DC-DC converter inside the control board. The isolated 12v supply needs to share a common ground with the full pack voltage. So, the control board black box would need an input from pack voltage minus. Other than that, I don't think there would need to be any other interface required.

So, to sum up:
Control board black box has battery pack B- input pin, auxiliary 12v plus input, auxiliary 12v minus input, 0-5k input pin1 and pin2, and PWM signal output pin. It could also have an input for ISP (in system programming).

Power board has battery pack B+ and B- input, M- output.

Is that it? Or did I miss something? That would be nice and clean. Great idea!
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