Immersion Oil Cooling Method of Discrete SiC Power Device in Electric Vehicle

Abstract

This paper introduces the design, optimization, and performance of immersion oil cooling for discrete SiC power devices in an electric vehicle's power control unit. The flow control of insulating oil, optimization of the flow channel, and the transition of discrete device packaging structure are studied. The research results show that immersion oil cooling features a better performance on the heat dissipation for discrete power devices in the power control unit. This provides basic technical support, including motor power electronic converter system integration and bus direct cooling, for the electric vehicle control system with a higher power density and lower thermal resistance in the future. In addition, compared with the cooling system of the power electronic converter in existing electric vehicles, the results show that the total thermal resistance of the immersion cooling method is lower than the traditional water cooling method. However, considering the smaller area, SiC MOSFET faces more severe heat dissipation challenges than Si IGBT.