Design Challenges of the 22 kV Solid-State Switch for Capacitor Discharge Application Based on 3.3 kV SiC MOSFET Super-Cascode

Due to the high voltage blocking capability and simple control method, the super-cascode topology can be implemented to develop a high-voltage switch. This paper presents a SiC MOSFET -based super-cascode switch used in the capacitor discharge circuit for medium voltage systems. Different design challenges including gate oscillations and gate discharge are mainly discussed. The solutions to overcome each issue are also provided with circuit modifications. Finally, a 22 kV super-cascode switch using ten SiC MOSFETs is developed in hardware for a 22 kV discharge circuit. The test results of the solid-state super-cascode switch as well as the discharge circuit are presented for performance verification.