An Active Gate Driver with Controllable Gate Current for SiC MOSFETs

An active gate driver (AGD) with controllable gate current (CGC) for SiC MOSFETs is proposed to reduce voltage overshoots and current overshoots. In the CGC-AGD, the controllable current overshoot suppression circuit and voltage overshoot suppression circuit are designed to control the rate of changes in current (di/dt) and voltage (dv/dt) to effectively reduce overshoots. Meanwhile, the current conversion circuit and the push-pull amplifier circuit compensate for the current reduction resulting from the overshoot suppression. This paper simulated the current and voltage overshoot during the switching process based on a double pulse test set up with a 1200V SiC MOSFET by LTspice software. The simulation results show that the current overshoot was reduced by 60% and the voltage overshoot was reduced by 22% when compared to the conventional gate driver (CGD). While compared with the AGD circuit, the current overshoot of CGC-AGD is reduced by 26% and the voltage overshoot is reduced by 19%. These results demonstrate that the CGC-AGD has better suppress on current and voltage overshoot.