I have a system that powers a transformer via a line to line power supply of 115Vac(L-N) for a total of 200Vac(L-L)
In order to control the ON/OFF of the transformer, the NEUTRAL line is used to control a set of MOSFETS triggered off by the Line to Neutral connection. The circuit is as following:
The circuit works well as intended during normal operation for ON/OFF purposes. But if I induce a diode (D7) to one of the phase (L1), the MOSFET attached to it will burn up (M1 in this case). I am using MOSFET IRFBF20S
I have simulated the circuit as I can't run measurements during the induced fault. But all I can think of is that somehow the body diode is conducting or the MOSFET is turning ON but not completly causing the RdsON to be too high.