Hi, I'm no expert in power electronics but i was building a plasma speaker once with two N channel MOSFETs in half bridge configuration. I noticed that they were heating a lot so i checked the voltages across drain-source.
Apparently they were turning ON while the gate voltage input was supposed to be OFF.
I asked a professor and he told me that in high frequency applications, above 20kHz, (i was commuting at 40kHz) electro magnetic noise might induce the treshold voltage (3-5V) at the gate and therefore turn on the MOSFET and short circuit the half-bridge.
He told me that the way to fix this is to wire a 10kOhm resistor between Gate and Source of each MOSFET.
I hope this fixes your problem
Good luck :grin: