Development of 50-kW isolated DC/DC converter with high-voltage IGBTs

The 6.5 kV insulated gate bipolar transistor (IGBT) is a new promising power device for high-voltage high-power applications. Due to its increased voltage blocking capability, the new HV IGBT can serve as a good replacement for GTO and IGCT thyristors in medium or medium-to-high power applications. One of its general application fields is railway traction. The paper discusses design and development considerations of the 50-kW auxiliary power supply to be used in 3.0 kV DC commuter trains. Focus is on the implementation of 6.5kV IGBTs in the primary inverter of APS to improve overall power density, system integrity as well as reliability of the whole system. For instance, topology selection, analysis and simulation of functional blocks of a converter for different operation points are described. A prototype of half-bridge isolated DC/DC converter with two 6.5kV 200A IGBT transistors was designed and built. Some design considerations are specified in the paper.