Impact of SiC MOSFET traction inverters on compact-class electric car range

Abstract

The advent of power devices based on Wide Band Gap (WBG) semiconductor materials, like the Silicon Carbide (SiC) MOSFETs, can improve the overall performance of the power converter systems, by reducing the conversion losses and enabling operation at higher switching frequency. This paper analyzes the range extension of electric vehicles (EVs) ensuing from the adoption of SiC devices for the traction inverter. As a case study, a compact-class electric car equipped with a Silicon (Si) IGBT traction inverter is considered. After introducing the driving cycle used to evaluate the range, the time graphs of currents and voltages applied by the inverter to the traction motor along the driving cycle are calculated. A loss model for Si and SiC devices is then formulated, and the losses of the Si IGBT inverter over the driving cycle are found and compared to the losses obtainable with a SiC MOSFET inverter. For the case study, the analysis shows that a SiC MOSFET inverter can extend the electric car range up to 5%.