Fractional Power Processing Architecture for Ultra-Fast Charging of Electric Vehicles

This paper proposes a novel fractional power processing (FPP) based solution for developing efficient ultra-fast charging (UFC) infrastructure for electric vehicles. The proposed strategy allows only a fraction of power to be processed through the converter, while rest of the power is bypassed through a series path from source to load. This improves the overall power conversion efficiency and reduces the current and voltage stress on the devices. In addition, the proposed FPP based architecture utilises the battery discharge voltage itself for charging of the battery, thus reducing the required DC voltage at the source. The operation of the converter is discussed and its advantages are mathematically established. A laboratory prototype of the proposed solution with current-fed resonant dual active bridge converter is developed and its steady-state behaviour is verified. Further, the performance of the proposed architecture is compared with the full rated converter through a 48 V battery charging, and the experimental results are presented.