Design Considerations of Auxiliary Power Supply Unit with SiC MOSFET for Lightweight Railway Vehicles

Railway vehicles are widely used worldwide. The weight reduction of railway vehicles can contribute to environmental friendliness by reducing energy and emissions. Hence, the investigations thereof are actively pursued. We herein propose to reduce the weight of the auxiliary power supply unit. The inverter of the auxiliary power source has been designed based on a Si IGBT. Si IGBTs are widely used in high-power applications. However, because Si IGBTs exhibit a low switching frequency and a relatively large switching loss, a large heat dissipation design is required. Therefore, a limitation in weight reduction exists. Meanwhile, SiC MOSFETs can drive a high switching frequency at a high power, and reduce heat dissipation due to low loss. Therefore, the SiC MOSFETs are validated through loss comparison and thermal analysis simulation. Additionally, the bus plate for minimizing stray inductance in the inverter drive was fabricated using various methods.