Active Gate Control for Multiple Series Connected SiC MOSFETs

Silicon (Si) is the most widely used in power electronic devices. However, due to its limitations regarding blocking voltage and switching frequency, wide band gap (WBG) materials have been under extensive research. Especially, Silicon carbide (SiC) device is expected to replace the Si device in many high voltage/power application. Although the low voltage SiC device that can replace the Si device is commercially available, device for high voltage and power application is under development. In order to achieve high voltage and power, series connection of SiC devices can be considered. Besides the advantage of series connection, it causes voltage unbalance issue that must be solved. In this paper, the active gate driver (AGD) control is used to balance the voltages. A gate resistance modulation method is presented for dynamic voltage sharing. It controls the gate current to adjust dv/dt. With different time of gate resistance modulation, the dv/dt of each device is adjusted to balance the voltages. The proposed method is verified in three different cases in Matlab/Simulink.