High-Voltage Isolated Power Supply Structure for Gate Drivers of Medium-Voltage SiC Devices

This letter proposes two novel gate driver isolation structures with potted printed circuit board (PCB) windings and cylindrical rod-based cores to drive medium-voltage silicon carbide devices. The first design uses two cylindrical rod cores, each for the primary and secondary winding, and uses a coupling coil to improve the magnetic coupling between the primary and the secondary side. The second design improves upon the first design and uses a single cylindrical core for both the primary and the secondary windings, eliminates the coupling coil, and brings upon the ability to drive a half-bridge structure. Both structures are designed to maintain the required insulation standards. The isolation structures achieve a peak partial discharge voltage greater than 15-kV peak, with an isolation capacitance within 5 pF. The structure of the PCB windings and the ferrite cores for the designs provides excellent repeatability and easy manufacturability. Experimental results validate the design and operation of the gate driver isolation structures.