An active gate driver with adjustable gate current for SiC MOSFET switching performance optimization

Silicon Carbide (SiC) MOSFETs are prone to current/voltage overshoot and high-frequency oscillation under high-speed switching conditions, which increases the stress of device and limits the efficiency and reliability of power converters. To address these issues, this paper begins by establishing a stage-specific model of the switching process of SiC MOSFETs, and analyses the generation mechanism of overshoot and oscillation as well as the influence of driving parameters. Based on this analysis, an active gate driver (AGD) with closed-loop feedback control of the gate current is proposed. By detecting the slopes of drain current (did/dt) and the drain-source voltage (dvds/dt), the AGD adaptively engages a shunt or a current injection circuit to dynamically change the gate current, thereby to realise the precise suppression of the current/voltage overshoots and high-frequency oscillations. Simulation results demonstrate that compared with the traditional gate drive method, the proposed AGD effectively optimizes the switching trajectory of SiC MOSFETs and significantly mitigates transient overshoot and high-frequency oscillations.