The Performance Comparison of the SiC and Si Mosfets Used in the 3-Phase Brushless DC Motor Drives for Electric Vehicles

Abstract

This study was carried out to compare the Si and SiC MOSFETs in the market used on motor driver circuits. A motor driver circuit is designed to run the brushless DC motors. Thanks to the semiconductors used in the driver circuit, the motor receives current as desired. While performing this task, the MOSFETs get hot and lose power. This situation changes according to the material structure used inside the MOSFETs. Hence, it is planned to compare Si MOSFETs that have been in the market for a long time and SiC MOSFETs that have been used recently under different loads and different temperatures circumstances. Si and SiC MOSFETs are placed in the motor driver circuit, which has the same structure in the simulation environment. The operation of the motor under no load and on different mechanical loads has been analysed. In these cases, the response of the MOSFETs to temperature changes was also analysed by changing the cooling temperature. As a result of the study, SiC MOSFETs were less heated and less power loss was observed than Si MOSFETs. It has been observed that when the mechanical load is high, the switching speed of Si MOSFETs decreases despite the speed of SiC MOSFETs is not affected. As a result of this study, it has been observed that SiC MOSFETs used in the motor driver circuit work more efficiently than Si MOSFETs for electric vehicles.