Differences in Dimensioning SiC MOSFETs and Si IGBTs for Traction Inverters

This paper describes, how the dimensioning of SiC MOSFETs and Si IGBTs for light railway differs in various aspects due to their specific electrical and thermal properties. Instead of comparing IGBT and SiC modules with the same nominal current, the output current during a load cycle is scaled to identify the maximum output capability for a given power cycling lifetime. Furthermore, it is shown which specific properties of the SiC MOSFET lead to the significantly increased current density in comparison to Si IGBT modules.