Gate drive unit DC-DC power supply for multi-level converters or series connection of IGBTs with high voltage insulation

Multilevel converters have become the dominant solution for medium voltage high power application [1]-[4]. These converter topologies e.g. M2C, SCHB, etc. generate new challenges for the DC-DC power supply (insulation, standby power, etc.) of the IGBT gate units. This paper presents an adaption of the cascaded flyback topology with high input voltage as DC-DC power supply for medium and high voltage multilevel cell converters or series connection of IGBTs. A mathematical model of the DCDC power supply is presented. This model and the selected operation regime of the converter allows the design of the converter as a single stage flyback DC-DC power supply. The performance and robustness of the proposed solution has been experimentally verified on a four stage cascaded flyback up to 1.4 kV/15 W as DC-DC power supply for IGBT gate drive units.