hello
I Design igbt based h bridge circuit for high voltage(300v) application. positive side igbt is on/off control,negative side igbt is controlled by pwm signals.run the circuit negative side igbt is failure after few seconds.any solution for this problem

 

You will get more answers if you post a schematic of the circuit. You explanation isn't very clear.

 

RE:""I Design igbt based h bridge circuit for high voltage(300v) application""
Impossible voltage. May be or 310 or 535 Volts or US the 154 Volts. Other-how You need to create a new standards for electro-compaanies.

RE:""positive side igbt is on/off control,negative side igbt is controlled by pwm signals"
Impossible circuitry. It would be unable to work any, if it is built this way.

RE:""run the circuit negative side igbt is failure after few seconds""
Some articles like a, the, to, of, etc may make the sentence less meaningless. However may quess Your problem is burning the igbt. It is obvious because the 50% of time You use a throughput current via it.

RE:""any solution for this problem""
Which one? That the circuit is meaningless or that there is strong will to violate the laws of nature??

Advice - post the circuit, probably You simply misunderstand how it works??