Power cycling methods for SiC MOSFETs

The evaluation of power cycling results needs correct measurement of the course of thermal resistance. Hence an accurate online measurement of the junction temperature is necessary. Different measurement and power cycling methods were evaluated. The method of measuring the voltage drop of the SiC MOSFET body diode pn-junction at low measurement current with sufficient negative gate-voltage was found most suitable one. In addition power losses during power cycling test should be generated in forward MOSFET-mode at high positive gate-voltage. Otherwise test results will not be application conform.