Applicability of thermal impedance spectroscopy via gate voltage variation for IGBTs and SiC MOSFETs

This article investigates which junction temperature swings arise from minimal sinusoidal superposition of the gate voltage in the on-state for IGBT and SiC MOSFET semiconductors. For this purpose, a simulation model is created based on extensive curve tracer measurements and validated by temperature measurements with different types of sensors in a laboratory experiment. The thermal impedance can be determined by temperature swings at different frequencies. Based on these findings, the feasibility of degradation detection during load cycles is investigated.