10kV SiC MOSFETs versus 6.5kV Si-IGBTs for medium frequency transformer application in railway traction

Nowadays, AC single phase power supply is widely used in railway electrification. To step down the input voltage, rail vehicles should board a heavy and bulky transformer. In recent years, several multilevel topologies including medium frequency transformers were proposed to replace the low frequency input transformer. The objective is to reduce weight and volume on the traction drive while increasing the efficiency. This paper focuses on the series-resonant DC/DC converter which is used in a well-known indirect structure. An opposition-method test bench allows to operate in rated conditions and hybrid power modules using 10 kV Silicon Carbide MOSFETs are compared to classical 6.5 kV Si IGBTs modules.