Characterization of Electro-Thermal Coupling Behaviors and Safe Operating Area of SiC MOSFET Modules in Pulsed Power Applications

With the development of high-temperature packaging technology, silicon carbide (SiC) MOSFETs can operate under high-temperature conditions with junction temperatures exceeding 175℃, providing a solution for pulsed power applications facing instantaneous high currents and significant temperature fluctuations. However, the electro-thermal coupling behaviors and safe operating area (SOA) of SiC MOSFETs in a wide temperature range are unclear, and there is a lack of guiding principles for SiC module packaging and heat dissipation design in pulsed power applications. In this paper, an electro-thermal coupling model of SiC MOSFET modules is established. The electrical model over a wide temperature range (25℃ - 375℃) is built in Simulink, and the thermal finite element (FE) model is established in COMSOL, while MATLAB script is used to implement interaction between the two models. Then, detailed analyses are conducted on the electro-thermal coupling behaviors of SiC MOSFET modules. Besides, the impact of packaging on the SOA of SiC MOSFET modules is researched. In addition, a transient junction temperature measurement method of SiC MOSFETs is proposed by using the on-state resistance Rds(on) as the temperature-sensitive electrical parameter (TSEP). Finally, the discharge experiments of the capacitor bank through resistive loads are carried out under short pulse and long pulse, respectively, and the experimental results are consistent with the model.