Quote:
Originally Posted by MazdaMatt
Mike, please fill me in on what way a lower frequency increases the size of components. Which components?
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Not mike, but this is the problem I'm running into... somewhat. I don't really know if it's a problem.
I sized the inductors so that there would be constant current (filtered output) in the output loop at a min current of 2A. However, that was at 100kHz. I lowered the switching frequency to 20kHz to reduce switching losses due to the initial heat problems. Now, at 20kHz, I don't have constant current in the output loop until I get up to about 5A. If I wanted constant current at a lower amperage, I'd need larger inductors.
Additionally, lower frequency requires more ripple current to be supplied by the input caps. More ripple current means more capacitors or larger capacitors or more expensive capacitors.
Anyway, I don't know yet if the un-filtered output at low current is a problem. I foresee it being an issue if I can't get a good current measurement below 5A. Hopefully I can filter the current reading from the current sensor to get an average current. (my hall effect DC clamp meter does this, so I should be able to as well?)