Power Loss in SiC MOSFET based Four-quadrant Switch

SiC MOSFET being fast switching, high voltage blocking, high junction temperature withstanding, and low loss device, has the edge over Si IGBT. Therefore, SiC MOSFET's applications are in high power density matrix converter, battery charger in electric vehicles, and many other. The matrix converter utilises four-quadrant switches, which allow both positive and negative current and block both positive and negative voltage. Since SiC MOSFETs being much better than Si IGBTs, the four-quadrant switches are realised using them. The conducting and blocking devices for the four-quadrant switch vary with the change in quadrant of operation, and the switching involves the turn ON and turn OFF of two devices. Therefore, the characteristics and power loss are bound to vary with the quadrant of operation. Very limited work is available on SiC based four-quadrant switches in the literature. Hence, a thorough investigation of the four-quadrant switch as a single entity along with power loss analysis is done in this paper. Further, this paper presents approximate conduction and switching power loss analysis of the four-quadrant switch. The research is performed by developing approximate mathematical equations for power loss and then testing the SiC MOSFET based four-quadrant switch in all four quadrants.