Power Loss Analysis in a SiC/IGBT Propulsion Inverter Including Blanking Time, MOSFET’s Reverse Conduction and the Effect of Thermal Feedback Using a PMSM Model

This paper presents a comparison of power losses for two silicon carbide (SiC) and one silicon insulated gate bipolar transistor (Si IGBT) power modules in a three-phase inverter, when considering the effect of blanking time and the MOSFET’s reverse conduction. The total power losses versus different switching frequencies are also compared for the three inverters. The focus of this paper is to determine the influence of junction temperature and thermal feedback on the power loss calculation. The analysis shows that, without accounting for the thermal feedback, the loss levels are substantially underestimated, 11-15% on the conduction losses of the SiC inverters and up to 18% on the switching losses of the IGBT inverter. The data is derived at a chosen high torque, low speed operating point of a permanent magnet synchronous machine (PMSM). The operating point is considered as a worse operating condition from the power loss perspective.