Optimized weak-drive window strategy for active gate driving of SiC MOSFETs

Silicon carbide (SiC) MOSFETs exhibit remarkable advantages in high-power conversion systems owing to their fast switching characteristics. However, such high-speed behavior also introduces severe voltage overshoot and current spike issues, posing significant threats to device safety and system reliability. Active gate driving (AGD) techniques have been proven effective in mitigating these problems, yet they often result in increased switching losses. To address this trade-off, this paper proposes an optimized weak-drive window strategy for active gate drivers based on a detailed analysis of the SiC MOSFET switching transients. By precisely adjusting the gate-drive voltage within the critical switching intervals, a balance between overshoot suppression and switching loss is achieved. First, a behavior model is established to reveal the stress mechanisms during the switching transients. Then, under open-loop conditions, the start and end instants of the weak-drive window are accurately defined. By significantly shortening and precisely locking the duration of the weak-drive window, targeted control over the critical period is realized, thereby effectively suppressing voltage and current overshoots while maintaining fast switching performance. Experimental results demonstrate that the proposed method achieves an excellent trade-off between power loss and overshoot suppression, verifying the effectiveness and engineering applicability of the proposed optimization strategy.