High Frequency Three-Phase CRM Inverter with Integrated Magnetics for Auxiliary Power Supply in Railway Applications

This paper presents the design of a 30kW wide-band-gap (WBG) device based 3-phase inverter for auxiliary power supplies (APS) in railway applications. The critical conduction mode (CRM) based soft switching technique allows the inverter to operate at a switching frequency over 200 kHz and to reduce weight and size of the magnetic components. The 2-channel interleaving operation helps reduce the total current ripple and negative coupled inductor can reduce switching frequency variation range. The inductor design is detailly studied to optimize the inverter efficiency and power density. Finally, the inverter prototype reaches a peak efficiency of 99.20% and power density of 2.7kW/L.