Driving Cycle Power Loss Analysis of SiC-MOSFET and Si-IGBT Traction Inverters for Electric Vehicles

This paper presents the calculation process for a detailed and fast analysis of EV traction inverter losses applying either MOSFETs or IGBTs in arbitrary driving cycles. An open-source tool was developed and every step of the calculation – starting with the driving cycle, the driving resistances, the set points of the permanent magnet synchronous motor, the modulation scheme, and finally the inverter loss calculation – is presented.A SiC-MOSFET and a Si-IGBT-based inverter with similar ratings and identical housing are compared exemplarily for various driving cycles. Static and dynamic losses derived from double-pulse tests of the SiC-MOSFET and continuous measurements from a dynamometer test bench are compared to datasheet values and calculation results. In all analyzed operation points, the SiC-MOSFET has lower losses than the Si-IGBT, although the performance advantage of the SiC-device is higher for driving cycles with a high amount of partial-load operation points. For high-power operation points or driving cycles with high power demands the advantage is less pronounced.