Study on the Imbalanced Voltage of Series-connected Active Power Semiconductor Devices in Power Conversion Systems

MOSFETs have been utilized in many applications for several electronic devices as switching power devices. However, the limited drain-source breakdown voltage makes it difficult to use one single MOSFET in high voltage power conversion systems. One of the attractive solutions to solve this issue is to connect MOSFETs in series, therefore, the applied voltage can be shared among the power devices to achieve higher efficiency and lower cost. Nonetheless, this circuit topology suffers from imbalance drain-source voltage (VDS) sharing among the series connected MOSFETs. The purpose of this paper is to investigate the imbalance voltage distribution caused by varied characteristics components between 3 kinds of most commonly used MOSFETs-Si, SiC and GaN.