Comparison of IGBT and SiC Inverter Loss for 400V and 800V DC Bus Electric Vehicle Drivetrains

Improving inverter selection for electric vehicles is a must when tackling overall vehicle efficiency and reduction of traction system losses. This paper investigates the efficiency benefits achieved by using an 800V dc bus voltage and wideband gap SiC carbide devices rather than a conventional IGBT inverter and a 400V dc bus. Inverters utilizing 600V IGBTs, 1200V IGBTs, 1200V hybrid silicon carbide (SiC) devices, and 1200V full SiC devices are modeled. The modeled loss for each inverter type is incorporated into a full electro-mechanical vehicle model as a way of accurately representing their behavior in an application. Measured data from experimental testing of a 180kW traction machine and a 1200V IGBT inverter were also used in developing and verifying the validity of the inverter model. Simulation results show around a 5% reduction in an electric vehicle’s energy consumption, and consequently a 5% increase in range, when a full SiC inverter is used. All results are normalized to a 600V IGBT inverter, showing that all the 1200V devices are more efficient and that the SiC devices show the most improvement overall.