Variable Gate Voltage Control for Paralleled SiC MOSFETs

Silicon carbide (SiC) MOSFETs have been widely used in different power conversion applications due to their advantages of high switching frequency and low loss. Parallel connection of SiC MOSFET is a cost-effective and necessary solution for high power rating converter. However, due to the differences of devices parameters, imbalance current exists, which may damage the system. In this paper, the issues of the paralleling SiC MOSFETs are well analyzed based on the static characteristics of the devices. Based on the analysis, we can find that the unbalanced transient current caused by the differences of threshold voltages are important and require to be mitigated when paralleling SiC MOSFETs. Then, the operational principles of the proposed variable gate voltage control are presented. Simulation and experiment results are presented and analyzed to validate the effectiveness of the proposed active gate driving method.