A high-accuracy switching loss model of SiC MOSFETs in a motor drive for electric vehicles

摘要

Power loss estimation of power electronic devices is essential to the efficiency optimization of motor drives in electric vehicles. However, most existing power loss models of silicon carbide (SiC) metal-oxidesemiconductor field-effect transistors (MOSFETs) have a low accuracy due to the neglection of parasitic parameters in the motor drive circuitry. In this paper, the voltage and current trajectories of SiC MOSFETs in the switching transition of a motor drive system are analyzed in detail. Based on the analysis, the conduction and switching losses of SiC MOSFETs in the motor drive inverter are modeled. Compared with the traditional power loss models, the proposed analysis model includes parasitic inductances and capacitances in circuitry and the MOSFET, and the reverse recovery loss of the body diode, etc. The experimental results verified that the proposed power loss model has higher accuracy than the conventional model.