Voltage Balancing Control with Active Gate Driver for Series Connected SiC MOSFETs

Silicon carbide (SiC) device is expected to replace silicon (Si) device in many high voltage and power application due to potentially higher switching frequency and voltage capabilities. Even though its potential voltage capability, the highest voltage rating of a single commercial SiC MOSFET is 1.7 kV. An alternative method to achieve higher voltage is a device series connection. However, it causes a voltage unbalance issue during turn-off state that can harm the devices. Therefore, the voltage balancing control (VBC) must be considered in device series connection. In this paper, a VBC method with active gate driver (AGD) is proposed. A gate resistance modulation method with a signal time delay is adopted for dynamic voltage sharing. The proposed method is experimentally verified.