Replacing Si-IGBT by SiC Mosfet in high Gain Inverter: Challenges and Opportunities

With the recent innovations and popularity of wide band gap devices (WBGD) like SiC and GaN Mosfets, it is very important to understand the feasibility of directly replacing their silicon counterparts by the WBGD, in power electronic converters, to achieve improved efficiency. This paper discusses the impact of replacement of Si-IGBT based design by SiC Mosfets in Boost-VSI. The challenges faced due to the sensitivity of SiC Mosfets to high frequency noises have been reported. Generally, modifying the gate drive circuit serves as a solution to the problem. This paper proposes a solution to deal with the challenges, without modifying the gate driver circuit. A 500W prototype of boost cascaded voltage source inverter (Boost-VSI) is designed and implemented using Si-IGBT as well as SiC Mosfet with same gate driver circuit. A comparative analysis of efficiencies of both the designs is done. Experimental results and analysis validate the significant increase in efficiency of the converter with SiC Mosfet.