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Abstract—Wide band gap (WBG) devices, like silicon carbide (SiC) MOSFET has gradually replaced the traditional silicon counterpart due to their advantages of high operating temperature and fast switching speed. Paralleling operations of SiC MOSFETs are unavoidable in high power applications in order to meet the system current requirement. However, parasitics mismatches among different paralleling devices would cause current unbalance issues, which would reduce the system reliability and maximum current capability. Thus, to achieve current balancing operation, this paper proposes a solution of using multi-level active gate driver, where the dynamic current sharing during turn-on and turn-off processes are achieved by adjusting the delays, intermediate turn-on and turn-off voltages. The static current sharing is maintained by regulating the static turn-on gate voltage, where the on-state resistance mismatch between different devices can be compensated. A double pulse test setup with two different SiC MOSFETs is built to emulate the scenario of worst case application with large differences of threshold voltage and on-state resistance. The experimental results demonstrate that the proposed active gate driver can achieve both dynamic and static current sharing operations for SiC MOSFETs with paralleling operation. Moreover, the system control diagram is discussed. Simulation studies are conducted to achieve closed-loop control of the paralleled SiC MOSFETs with the aid of the active gate driver approach. 

Wide band gap (WBG) devices have been widely adopted in numerous industrial applications. In medium voltage applications, multi-level converters are necessary to reduce the voltage stress on power devices, which increases the system control complexity and reduces power density and reliability. High voltage silicon carbide (SiC) MOSFET enables the medium voltage applications with less voltage level, simple control strategy and high power density. Nevertheless, great challenges have been posed on the gate driver design for high voltage SiC MOSFET. Wireless power transfer (WPT) can achieve power conversion with large airgap, which can satisfy the system isolation requirement. Thus, in this article, a WPT based gate driver is designed for the medium voltage SiC MOSFET. The coil is optimized by considering voltage isolation, coupling capacitance, size, and efficiency. Experimental prototype was built and tested to validate the effectiveness of the proposed WPT based gate driver.