A Robust 10 kV SiC MOSFET Gate Driver with Fast Overcurrent Protection Demonstrated in a MMC Submodule

This paper focuses on a robust 10 kV SiC MOSFET gate driver with an improved desaturation protection scheme for overcurrent protection. The gate driver is designed for 10 kV/20 A SiC MOSFETs in a modular multilevel converter (MMC) submodule. The gate driver has short circuit protection, status feedback in every switching cycle, dead time insertion, and undervoltage lockout (UVLO) function to support robust continuous operation of the MOSFET and converter. Practical design considerations are elaborated to achieve these functions. With a digital blanking time of 600 ns, the improved desat protection achieves a response time of <350 ns under hard switching fault (HSF), and a response time of <200 ns under fault under load (FUL) and flashover fault. All functions of the gate driver are fully validated in a MMC submodule with a rated dc-link voltage of 6.5 kV.