Effects of Current Commutation Methods on SiC MOSFET and Si IGBT Based 4-Quadrant Switches

Silicon Carbide (SiC) MOSFETs are promising replacements for Silicon (Si) IGBTs in various power electronic topologies. While extensive research exists on SiC MOSFET based 2-quadrant switches, studies on 4-quadrant switch topologies remain limited. A 4-quadrant switch is typically formed by combining multiple 2-quadrant switches such as MOSFETs, IGBTs, or diodes. Designing such topologies presents challenges, including commutation methods (2-step and 4-step), finite switching speed constraints, variable ON state voltage drops, and quadrant-dependent transition (turn ON/OFF) times. This research systematically investigates these challenges through analysis, simulation, and experimental validation in a controlled FPGA based test environment. The study focuses on selecting an optimal commutation method, analysing the impact of 2-step and 4-step switching on transition times and ON state voltage drops, and evaluating the maximum switching frequency and efficiency of converters utilizing SiC MOSFET based 4-quadrant switches. The findings demonstrate the advantages of these converters in terms of reduced transition times, higher switching frequencies, and improved efficiency, establishing SiC MOSFET based 4-quadrant switches as a viable alternative to Si IGBT based designs.