A Temperature-Dependent Analytical Model of SiC MOSFET Short-Circuit Behavior Considering Parasitic Parameters

Abstract

The superior electrical and thermal characteristics of silicon carbide (SiC) MOSFETs bring major challenges to its short-circuit reliability. To fully understand its short-circuit mechanism, estimate its safe operating area, and provide guidance for circuit design, it is crucial to establish a theoretical model to quantize the relationship between circuit parameters and short-circuit behavior of SiC MOSFETs. A temperature-dependent analytical model considering the parasitic inductances, nonlinear junction capacitances, and temperature dependence of the channel current is proposed in this article, which uses only the parameters in the datasheet or provided by manufacturers. The proposed model is established based on the analysis for each short-circuit stage in both single-device configuration and half-bridge configuration, and the quantitatively analytical results of the transient short-circuit waveforms, energy loss, and junction temperature rise can be calculated by solving the model. The accuracy of the analytical model is verified by comparing the analytical results with the experimental results. Furthermore, the effects of varied parameters on the short-circuit behavior are evaluated by the proposed analytical model. And the corresponding circuit design guidance for higher short-circuit reliability is given.