An Online Junction Temperature Monitoring Method for SiC MOSFET Based on Drain-source Voltage Change Rate During Turn-on Transient

Abstract

This paper analyzes the turn-on transient of silicon carbide (SiC) metal oxide semiconductor field effect transistor (MOSFET) based on the basic physical equation, and the analysis model of drain-source voltage change rate (dv ds/dt ) during turn-on transient is derived. The change rule of dv ds/dt of SiC MOSFET during turn-on transient and its temperature-dependent characteristics are studied, and the calculations generally fit the measurements well. Experimental results show that the magnitude of turn-on dv ds/dt increases with increasing temperature and exhibits good linearity. The influence of driving conditions on the temperature dependence of the turn-on dv ds/dt is also analyzed through the model, finding that the temperature sensitivity can be improved by reducing the driving forward bias voltage and increasing the driving resistance. Finally, the online junction temperature monitoring experiments are used to verify the accuracy and effectiveness of the proposed method.