Comparison of Si SJMOS and SiC MOSFET for Single Phase PFC Application

Silicon superjunction MOSFET (Si SJMOS) with SiC Schottky diode is a popular choice in single-phase dual-boost PFC converter applications due to their lower cost, standard gate driving voltage, and high reliability. SiC Schottky barrier diode (SBD) can mitigate the issue of poor reverse recovery of the body diode of Si SJMOS and improve the converter’s efficiency. SiC MOSFETs are now available in the voltage range of 600-650V, where they can be used as an alternative to the Si SJMOS. It is generally believed that using SiC MOSFET in place of Si SJMOS will increase the converter’s efficiency. However, SiC MOSFET in this voltage range (600-650V) has a similar on-state performance to Si SJMOS. On the other hand, SiC MOSFET is expensive when compared with Si SJMOS. Also, being a new device, the reliability data for SiC MOSFETs from the field is not available. This work presents a comparative study of the switching dynamics of similarly rated SiC MOSFET and Si SJMOS, where SiC SBD is used as a free-wheeling diode. Two sets of 650V SiC MOSFET and Si SJMOS of different current ratings are considered for comparison. The experiments are conducted for a range of gate resistance and operating currents.