Comprehensive comparison between SiC-MOSFETs and Si-IGBTs based electric vehicle traction systems under low speed and light load

In this paper, the performance of both SiC-MOSFETs and Si-IGBTs based electric vehicle (EV) traction systems under low speed and light load are investigated and compared comprehensively, particularly from efficiency point of view. Both conduction loss and switching loss of SiC-MOSFET are analyzed and modeled taking temperature effect into account. Such methodology yields more accurate prediction of losses. The temperature distributions of the two inverters with the same heat sink are described by ANSYS finite element analysis (FEA), respectively. This paper first explore that the motor has extreme high efficiency under low speed and light load when it is driven by SiC-MOSFETs based inverter, which thanks to higher switching speed of SiC MOSFETs. Experimental results show that the SiC-based traction system has higher system efficiency compared to the Si-based traction system under low speed and light load. And experimental results also give more confidence of the losses models of SiC MOSFETs.