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Maytech SUPERFOC6.8 50A sub zero cooling for fun and burst power. Mosfet power loss?

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Gargazol
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Maytech SUPERFOC6.8 50A sub zero cooling for fun and burst power. Mosfet power loss?

Hi

 

I have 2x Maytech SUPERFOC6.8 50A, and I’m playing with the idea of testing how much burst amp I can get out of them at different temperatures. I know I could just buy bigger controllers, but this is purely for fun and finding the limit of the units :)

My thought was mounting a copper block to the mosfet case on both sides and cooling this block with a peltier element. The hot side would be cooled by a CPU cooling block and a fan.

I am aware this is super inefficient and will drain the battery fast.

The whole board would be sealed in a box to prevent moisture and cooled to the wanted temperature before starting the tests.

My hope is I could cool the board to maybe -5 degrees c, and this could at the same time lower the RdsOn just a little, so it won’t heat up just as fast.

 

My question for you guys is now. How much heat (W) is it I need to remove from the board? I guess most heat comes from the mosfet switching loses, but I have no idea how much this really is. I will run in FOC mode at either 20 or 40Khz switching frequency.

TheFallen
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At the end of the day even if the MOSFETs are at -20°C if the die gets too hot too quickly it will break. I don't think you're going to get much in the way of gains.