Performance comparison of 10 kV#x2013;15 kV high voltage SiC modules and high voltage switch using series connected 1.7 kV LV SiC MOSFET devices

Abstract

. The 10 kV to 15 kV SiC MOSFET and 15 kV SiC IGBT are state of the art high voltage (HV) devices designed by Cree Inc. These devices are expected to increase the power density of converters and are expected to replace 4.5 kV/6.5 kV Si IGBTs. However, these are not commercially available. On the other hand low voltage (LV) 1.7 kV SiC MOSFET is commercially available, and it is replacing existing 1.7 kV Si-IGBT and it can meet immediate need of medium or high voltage (MV or HV) converter applications with series connection of these devices and can replace existing 4.5 kV/6.5 kV Silicon (Si) IGBT. Therefore, 10 kV-15 kV SiC modules and series connected 1.7 kV SiC MOSFET will be competing with each other for MV and HV converter applications. Hence, to explore the capability of low voltage SiC devices for MV or HV applications, a HV switch (10 kV-15 kV) using the series connection of 1.7 kV/300 A SiC MOSFET modules has been investigated. For making HV switch using series connected 1.7 kV SiC MOSFET, a simple RC snubber method has been used for dynamic voltage sharing to offset the turn-off delays due to mismatch of device characteristics and gate signals. Experimental switching characterization with different values of RC snubbers has been carried out, and a methodology has been outlined to find the optimal RC snubber which gives minimum voltage sharing difference, snubber losses and total semiconductor losses. In addition, experimental switching characterization of 10 kV-15 kV SiC modules is presented. Furthermore, a performance comparison of HV 10 kV-15 kV SiC modules and HV switch using series connected 1.7 kV SiC MOSFETs is presented in this paper.