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Old 10-22-2015, 03:50 AM   #2222 (permalink)
e*clipse
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Join Date: Jul 2010
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Honestly, Paul, I wouldn't go to that trouble.

I think that between what SBE shows on their various tests and what I've seen on my simulation, the specifics are very important. IMHO, Doing a test with a different inductance, resistance and bus connection system would be too much variation.

I think the motor inductance has a very strong relation to the ripple current, for example. Other factors like bus impedance and switch "on" resistance also had big affects on the ripple current.

I did get through to someone at SBE who was a little more willing to help. I asked him for at least some rough parameters that would allow me to see if my model was reasonably accurate. Here's the reply; it's good to see that the model is working!

Quote:
The ripple current usually equal to 60% current rated. Base on ripple current number to decide how big capacitance you need..

But the ripple voltage will be too high if the capacitance is too low. So you should decide what’s the capacitance your system minimum needed.

Thanks,

Wayne Liu
SBE
Paul - have you been able to check out these capacitors with respect to the turn-off voltage spike? A while ago I though you said that someone @ SBE said a capacitor rated for 700V would be adequate. Or maybe I'm remembering something else?
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