Effect of Commutation Control on Switching Frequency of SiC based Four Quadrant Switch

Abstract

SiC MOSFET has a clear edge over Si IGBT due to its enhanced characteristics like fast switching, high voltage blocking, high junction temperature withstanding, and low loss. Among the vast applications of SiC MOSFETs, high power density matrix converter require four quadrant switch. This switch allows alternating current and voltage to pass through and are capable of blocking them. One of the vital aspects of this converter is the current commutation. The standard commutation techniques are two step and four step. Although SiC MOSFETs are high switching speed devices, these commutation processes cause commutation delays. Hence, the effect of commutation control on the switching frequency of SiC MOSFET based four quadrant switch needs investigation. FPGAs are used to reduce the commutation delays due to parallelism and pipelining. However, research on maximum switching frequencies possible in SiC MOSFET based four quadrant switch is missing in the literature. Therefore, the paper finds the minimum commutation delays and the maximum switching frequencies in four quadrant switches using equations. It also explains the 3×1 matrix converter and the effect of FPGA on commutation delays with the help of simulation results. A laboratory prototype is used to implement and verify the investigations.