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Old 10-16-2015, 10:10 PM   #2200 (permalink)
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Originally Posted by MPaulHolmes View Post
You can use the same capacitor for the boost section. Think of the boost as just a 4th phase. Hooked up identically as the other 3 phases. But instead of going to a motor lead, it goes to the boost inductor.

That is beautiful, by the way!!
Thank you! It's one of those waking thoughts that worked itself out... I guess if you're nutty enough to be thinking about this all the time, perhaps some inspiration will come along...

That's great news about sharing the capacitor. Then a serious question I still haven't found a good answer for - maybe you have: How much capacitance will work? In this case the inductance would be ridiculously low. In fact, those "plates" are sort of a capacitor. Do you have a definitive source for some equations on this?

Those boost switches would probably need to carry more current than a phase leg. For example, if the battery voltage is 1/2X, the boost switches need to carry 2X, right?

Oh yea - there is the issue of measuring phase current. I guess it would be possible to use a sensor around the output leads. Do you have a cleaner suggestion? Maybe those little hall effect sensors on 1/2 of each output??

And on assembly - this would require soldering big pieces of copper. As far as I can tell, it would need to be all done at once. Any suggestions would be extremely helpful..
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