Electroluminescence-Based Junction Temperature Measurement Approach for SiC Power MOSFETs

The measurement of the junction temperature of power semiconductor devices during operation is highly relevant for efficient power electronic applications. This paper presents a novel galvanic isolated sensing approach for the online junction temperature measurement of a silicon carbide (SiC) mosfet. It is based on the temperature-dependent changes in the spectrum of the light emission from the body diode of the SiC mosfet. The spectrum exhibits two characteristic peaks at roughly 380 nm and around 480 nm. The first peak's intensity increases with rising temperature, whereas the other decreases. Consequently, the junction temperature can be derived from the ratio of the filtered intensities of those two wavelength regions. The proposed method is studied on the basis of a virtual experiment and experimentally validated by means of static characterization and dynamic double pulse measurement.