A Novel Two-Stage Power Conversion Method Suitable for 1MHz-LDC of Electric Vehicles

초록

Low-Voltage DC-DC converters (LDCs) in electric vehicles require high power density and high efficiency operation over the wide range of load and input voltage variations. This paper introduces a novel topology which combines three 1 MHz half-bridge (HB) LLC resonant converters and an inverting buck-boost (IBB) converter to adjust the output voltage without frequency modulation. The switching frequency of the proposed converter is fixed at 1 MHz to achieve a constant frequency operation for the resonant converter. In the proposed topology, Gallium Nitride (GaN) devices and planar transformers are employed to optimize the converter operation at high frequency. A 1-MHz/1.8 kW-400/14 V prototype converter is built to verify the feasibility and the validity of the proposed LDC topology.

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