Prognostics of Power MOSFET due to unclamped inductive switching

In this paper the real time prognostics of power MOSFET is presented experimentally through repetitive unclamped inductive switching based accelerated aging test. As per MIL Handbook 217F, the failure rate of electrolytic capacitors is very high followed by switching transistors. In power electronic systems power MOSFETs are preferred switching transistors for high frequency applications. The practical reliability of MOSFET is much different from their datasheet due to the thermal stress arising from the real time operation. In this paper, the wear out conditions of MOSFET due to avalanche energy stress is determined from the junction temperature rise due to unclamped inductive switching based accelerated aging test. The test will help in selecting the switching power MOSFET for the power electronic converters.