Active gate control for series connected SiC MOSFETs

Silicon (Si) is the most widely used in power electronic devices. However, due to its limitations regarding switching frequency and blocking voltage, 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. However, the commercially available SiC devices need to be improved to achieve higher voltage rating. To achieve high voltage and power, series connection of devices is promising alternative. Despite of the advantage of series connection, it causes critical issue which is voltage unbalance that harms the devices. Therefore, the voltage balancing control must be performed in devices series connection. In this paper, the active gate driver (AGD) control method is proposed to balance the voltages. A gate resistance modulation method is applied for dynamic voltage sharing. The proposed method is verified in LTspice siumlation.