Active Gate Control method for Voltage Balancing of Series-Connected SiC MOSFETs

The series connection of silicon carbide (SiC) MOSFETs and the cascaded system allows operating at a higher voltage than the rated voltage of devices. However, the unbalancing voltage problem occurs in the series-connected devices. The main reason for the unbalancing voltage problem is the parasitic capacitance of the device's gate to the ground. There are several methods for balancing the series-connected device voltage. The snubber circuits, active clamp circuits and the active gate driver. In this paper, the active gate driver method is proposed to control the unbalanced device voltage. Also, the device voltage sensing circuit and the feedback controller are designed in detail. Finally, the proposed active gate driver is verified with the simulation.