Gate Driver Power Supply With Low-Capacitance-Coupling and Constant Output Voltage for Medium-Voltage SiC MOSFETs

With the development of wide band-gap devices, Silicon Carbide (SiC) semiconductor devices in 10 kV–15 kV voltage class offer potentials in medium-voltage (MV) systems. To ensure reliable operation of these MV SiC devices, gate driver power supplies must meet specific requirements: MV isolation capability, low coupling capacitance, stable performance across fluctuating voltage potentials, and assembly convenience. This paper proposes a customized gate driver power supply solution. The proposed core-series-coupling planar transformer meets the specified requirements and significantly reduces common-mode capacitance by series connection of core, while maintaining ease of manufacturing. Additionally, the open-loop voltage regulator circuit model ensures precise output voltage by accounting for winding resistance and magnetizing inductance. This paper presents an MV SiC gate driver that achieves a partial discharge inception voltage of 11.5 kV and the transformer exhibits a low coupling capacitance of 0.42 pF. Additionally, this paper conducts a 6 kV / 30 A double pulse test, demonstrating the robust performance of the gate driver even at switching speeds of 133.9 V/ns during turn-off and 111.6 V/ns during turn-on transients.