High voltage IGBTs in medium frequency traction power supply

Abstract

A converter system comprising series-connected converter submodules based on medium-frequency (MF)-DC/DC converters can replace the conventional traction transformer. This reduces mass and losses. The use of multilevel topology permits the connection to the HV catenary. A suitably chosen DC link voltage avoids excessively oversizing the power semiconductors, while providing sufficient redundancy. The medium-frequency switching performance of typical and dedicated 6.5kV IGBTs has been characterized and is discussed here (→ZCS, ZVS).