Energy Loss Analysis in a SiC/IGBT Propulsion Inverter over Drive Cycles Considering Blanking time, MOSFET’s Reverse Conduction and the Effect of Thermal Feedback

Abstract

This paper presents a comparison of power and energy 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. Two different drive cycles are chosen for the loss comparisons, the ECE-City manual and the Worldwide Harmonized Light Vehicles Test Cycle (WLTC). For the WLTC, the urban and highway phases are included. The focus of this paper is to determine the influence of the thermal feedback on the power loss calculation over the driving patterns. The analysis shows that, without accounting for the thermal feedback, the power loss levels are considerably underestimated, up to 1.5% on the conduction losses of the SiC inverters and up to 3% on the switching losses of the IGBT inverter over the ECE-City manual. Similarly, for the WLTC drive cycle, a loss increases up to 3.5% on the conduction losses of the SiC and up to 6% on the switching losses of the IGBT inverters are observed, when considering the thermal feedback. The data is derived at a chosen high torque, low speed operating point of a permanent magnet synchronous machine (PMSM) over the drive cycles. The operating point is considered as a worse operating condition from the power loss perspective.