A Current Source Gate Driver for Reducing Switching Losses in SiC MOSFETs Under Hard Switching Conditions

The switching speed of silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors (mosfets) is limited when using conventional voltage source gate drivers (VSDs) with fixed gate resistance. This article proposes a novel current source gate driver (CSD) for SiC mosfets to reduce switching losses under hard switching conditions. Unlike conventional CSDs that rely on a single inductor, the proposed CSD utilizes auxiliary inductors to accelerate gate capacitance charging and discharging during switching transients, enabling faster switching speeds. Compared to existing CSDs, the proposed design further reduces both turn-on and turn-off times, significantly lowering switching losses. The proposed CSD consists of seven control switches, four diodes, and three inductors, with a detailed discussion of its logic circuit and design methodology. Its operating principles during switching transients and the relationship between gate current and switching losses are theoretically analyzed. A double pulse test is conducted to validate the experimental performance, comparing the proposed CSD with conventional VSD and existing CSDs. Under light-load and full-load conditions, the proposed CSD reduces total switching losses by up to 53.1% and 73.5%, respectively, compared to the conventional VSD. Experimental results confirm that the proposed CSD effectively reduces switching time and losses, demonstrating its improved efficiency.