A 200 kW high-efficiency and high-power density xEV motor controller based on discrete SiC MOSFET devices

As one significant component of the Electric-Driven System of xEV (all types of electric vehicles), motor controllers have been widely applied and researched. However, the performance of controllers based on Si IGBT is limited due to the characteristics of semiconductors, while the volume and weight of SiC MOSFET modules limit the power density of controllers. Therefore, a scheme for motor controllers based on paralleled discrete SiC MOSFET devices is exhibited in this paper. First, the paper analyzes the current sharing problem of paralleled devices, which is a critical problem limiting the efficiency and power density of the controller. Furthermore, according to the analysis results, a comprehensive optimized scheme for motor controller design is proposed from three aspects of device parameter selection, circuit symmetrical layout, and spatial structure design. The design effectively improves the power density and efficiency of the controller. Finally, this paper carries out simulation analysis and mechanical back-to-back tests based on an actual prototype, verifying the effectiveness of the proposed scheme. The test results show that the rated power of the motor controller is up to 200 kW, the power density is more than 50 kW/L (and 50 kW/kg), and the peak efficiency is up to 99.3%.