A Closed-Loop Active Gate Driver of SiC MOSFET for Voltage Spike Suppression

Abstract

The development trend of power converter is high frequency, high efficiency and high-power density. Compared with silicon-based power devices, SiC MOSFET has been widely used because of its fast-switching speed, low switching loss and high operating temperature. However, voltage spikes and oscillations are easy to occur during the high-speed turn-off of devices, which will seriously threaten the safe operation of power electronic converters. To solve this problem, based on the detailed analysis of the device turn-off process, a closed-loop active gate driver circuit based on dv/dt voltage feedback is proposed. Based on the small signal analysis of control oriented MOSFET driver circuit, the stability of dv/dt control is studied, and the influence of key parameters of driver circuit on the stability of control system is analyzed. The experimental results show that compared with the conventional gate driver, the proposed active gate driver can effectively suppress the peak voltage in the turn-off process without significantly increasing the switching loss.