Hardware Design and Testing of Compact Power Submodule with 3.3 kV SiC Devices

This paper presents a compact half-bridge submodule hardware design based on a 3.3 kV SiC MOSFET, suitable for applications such as medium- to high-voltage motor drives, photovoltaic grid connection, and fast charging of electric vehicles. First, the selection of power device models was completed, followed by the determination of an appropriate isolated power supply and the design of a gate driver circuit with high CommonMode Transient Immunity (CMTI). The designed gate driver circuit integrates functions such as short-circuit protection, undervoltage protection, and Miller clamp. Additionally, the capacitor design solution was carefully evaluated, balancing the Equivalent Series Resistance (ESR), Equivalent Series Inductance (ESL), and volume of the capacitors, ultimately achieving a solution with high compactness and low ESL, with a capacitor volume of 1.8 L and an ESL of only 12.6 nH. The paper concludes with the development of a module prototype, along with the setup of a buck converter and a 1.5 kV double-pulse test platform to evaluate the performance of the designed submodule. Experimental results show that, under a switching speed of 50 kV/μs, the voltage overshoot during device turn-on is only 13.3%, and the parasitic inductances of the main circuit and bus capacitor are well controlled.