A Self-Sustained Circuit Building Block Based on 10-kV Silicon Carbide Devices for High-Voltage Applications

This paper presents a self-sustained circuit building block (CBB) that utilizes 10-kV silicon carbide (SiC) devices as the main switches. The CBB achieves a self-sustained operation by powering the gate drives of its main switches with the energy from its dc bus capacitor. The CBB can serve as one of the submodules in a multilevel converter for high-voltage applications. This paper focuses on the design of the 10-kV SiC device's gate drive and its associated auxiliary power supply (APS). The gate drive and its APS are the major technical challenges in the CBB development. The gate drive in the CBB features a common mode transient immunity (CMTI) over 200 kV/μs and fast protection functions. Its APS is based on an active voltage divider concept and achieves 7-kV input voltage with a simple circuit structure and control scheme. The operational principles and design guidelines of the gate drive and its APS are presented in detail. Test results of the CBB in a double-pulse test setup with a 7-kV dc bus voltage are presented to validate the design. Reliable operation of the CBB is demonstrated under dv/dt up to 100 kV/μs.