HOW TO PROTECT MOSFET OR IGBT FROM VOLTAGE SPIKE

PROBLEM
I AM TRYING TO BUILD A FULL BRIDGE HIGH VOLTAGE 50 HzINVERTER (300V DC).
WHEN SWITCH ON THIS MOSFET WILL DAMAGED.I HAVE RECTIFIED 230 V AC .
used Fan7392 driver
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SOLUTIONS THAT I HAVE ADDED

 MOV OF 320V ,20mm dia
 1uF polyester capacitor across dc 300v power supply bus


common mode choke- ferrite  connected series with dc bus and inverted card

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  •  uf4007 -fast recovery diode across ground and high side mosfet source in reverse bias
  •  gate resistor of 100ohm (previously it was 10 )
  • 15v zenor across driver power supply 
  • 1n4148 diode across gate resistor for fast turn off
  • 15v zenor across gate and source of mosfet