Performance Evaluation of 3.3 kV SiC MOSFET and Schottky Diode Based Reverse Voltage Blocking Switch for Medium Voltage Current Source Inverter Application

SiC power devices are used for medium-voltage (MV) motor drive and traction applications due to their higher temperature operation, switching frequencies, and higher efficiencies than Si-based devices. This article investigates three 3.3 kV reverse blocking or current switch configurations for their suitability in MV current-source inverter (CSI) applications. The three configurations are 1) Type I - SiC MOSFET and series Schottky diode; 2) Type II - SiC MOSFETs connected in common-source (CS); and 3) Type III - SiC MOSFETs connected in common-drain (CD) configuration. The switch configurations are characterized by comparing their on-state and switching performance at different junction temperatures varying from 25°C to 125°C. The results are used to evaluate three-phase CSI losses with three different switch configurations and choose the preferred switch configuration for MV-based CSI applications based on inverter efficiency while considering a wide range of operating points. The permissible limits of a 3.3 kV Type I switch-based CSI are presented, thus providing a safe operating area (SOA) of the switch configuration for a CSI application. Finally, the CSI is built using Type I switch configuration and is experimentally validated with an R-L load.