Present Status of SiC based Power Converters and Gate Drivers – A Review

Wide band gap (WBG) based semiconductor devices are considered to be the next generation of power electronic devices due to their higher switching frequency of operation with reduced device losses compared to their strong competitor Si based switches. Among the WBG devices (SiC, GaN), SiCs (Silicon Carbide) are considered to be the most preferable choice for the medium and higher power levels due to their reliability in physical construction. The major part of the loss reduction in SiC devices come from the lower on state resistance and the reduction in the reverse recovery losses associated with the antiparallel diodes. The total estimated loss reduction can be around 70% in SiC based converters compared to the Si based ones. However, there are issues related to driving these switches at safer operating area (SOA) with reduced switching losses at higher switching frequencies (20 kHz – 100 kHz), which also leads to a significant EMI/EMC issues in comparison to Si device (Operates at 20 kHz maximum). Higher switching frequency of operation further increases the effect of stray capacitances and associated oscillation which might not be acceptable for stable system operation. This paper will present different applications of SiC based inverters, challenges associated with high switching frequency SiC driver design and the problem with commercially available drivers.