Junction temperature monitoring of silicon carbide MOSFET based on turn‐off voltage spike

Abstract

Because of the advantages of high switching speed, silicon carbide (SiC) devices are widely used in high‐power power electronic equipment. Real‐time monitoring of junction temperature is very important for the safe operation of equipment. There have been many studies on traditional junction temperature monitoring methods based on Si IGBT, but the dynamic characteristics of SiC MOSFETs are changed due to their different physical structure and parasitic parameters, which make the traditional methods no longer applicable. In this paper, the junction temperature can be extracted from the switching process of SiC MOSFET by using the turn‐off voltage spike as the index of thermosensitive electrical parameter (TSEP). In addition, the effect of working voltage, current, and different materials on turn‐off voltage spike is also studied. The simulation platform of Ansys/Simplorer and the experimental test platforms are built, and the theory of junction temperature detection based on turn‐off voltage spike is verified. The simulation and experimental results show that turn‐off voltage spike is a feasible TSEP, which can be used to extract junction temperature of SiC MOSFET with good linearity and instantaneity.