Compact three phase inverter in Silicon Carbide technology for auxiliary converter used in railway applications

Abstract

The low switching losses of the Silicon Carbide (SiC) components enable power converter to operate at higher switching frequencies and higher junction temperature. Operating at high switching frequencies enables to reduce volume and weight of passive component. Operating at high junction temperature helps to reduce size and weight of the cooling system or even enables the use of a natural cooling system. As a result, reduction of end-system cost can be achieved. This paper explains difficulties of using Silicon Carbide Power switch working at high switching rate and high junction temperatures. The paper explains how to overcome these difficulties. It demonstrates that it is not obligatory to use high technology gate driver or high temperature power capacitor in a Silicon Carbide converter. The paper demonstrates that if the design of the complete system is “well done”, classical technology could be used. So a “low cost” Silicon Carbide power converter is achievable. Target applications are auxiliary converter for railway applications. An optimized SiC three phase inverter is built. This inverter uses a Silicon Carbide power MOSFET of 1200V and 100A from Cree. Some design and optimization points of the inverter are demonstrated. Experimental results are shown at the end of the paper.