DC-DC Converter Architecture for Fast Electric Vehicle (EV) Battery Charging Applications

This paper introduces an innovative DC-DC converter architecture designed for fast Electric Vehicle (EV) battery charging. The proposed system utilizes a novel multi-primary, single secondary adder transformer. Multiple resonant full-bridge inverters supply the transformer's primaries, and the combined secondary voltage is rectified by an active bridge to power the EV battery. This input-parallel-output-series architecture promotes modularity and ensures inherent current sharing. The converter achieves a wide output voltage range (250-920V) and a peak power output of 180kW while maintaining soft switching transitions across the entire operating voltage range. Detailed mathematical modeling is demonstrated for system design and selection of temporal characteristics under various load conditions. To validate the concept, a scaled-down prototype with a voltage range of 47V-210V and power range of 0.35kW-1kW, demonstrating peak efficiency of 97.2% was developed.