A Single Voltage-Balancing Gate Driver Combined With Limiting Snubber Circuits for Series-Connected SiC MOSFETs

Abstract

Silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors (MOSFETs) are required to be connected in series to meet the high-voltage requirement since the blocking voltage of a single device is limited. In order to solve the voltage unbalancing problem in such a series-connection application, a single voltage-balancing gate driver combined with limiting Snubber circuits is proposed in this article. This gate driver only requires one standard driver circuit to drive two series-connected SiC MOSFETs by adding simple coupling circuits, and limiting Snubber circuits are applied for voltage balancing, and thus, low-cost, simple structure and high reliability are acquired. The analysis is given to demonstrate the working process of such a circuit structure, and the key parameters’ design and setting are focused on. In the LTspice simulation of two SiC MOSFETs in series, the proposed gate driver shows good voltage balancing performance as the power loop current increasing. Besides, the branch of series-connected SiC MOSFETs is in reliable ON- or OFF-state during steady process. Finally, the experimental results further verify the performance of proposed single voltage-balancing gate driver.