A Multiport Partial Power Processing Converter With Energy Storage Integration for EV Stationary Charging

Battery storage system (BSS) integration in the fast charging station (FCS) is becoming popular to achieve higher charging rates with peak-demand shaping possibility. However, the additional conversion stage for integrating the BSS increases the system losses, size, and cost. The concept of a partial power processing converter (PPPC) can mitigate this effect. Compared to conventional used full power processing converter (FPPC), PPPC reduces the amount of transferred power from the BSS to the electric vehicle (EV) by the converter. As a consequence, the power losses generated by the converter are reduced, leading to lower sized converters and higher system efficiencies. This article proposes a dc/dc multiport converter that allows the integration of battery storage in FCS based on a partial power processing concept while maintaining the specific requirements in terms of isolation for FCS. The proposed three-port partial power processing converter (3P-PPPC) is derived from the commonly used triple active bridge (TAB) converter. The resulting design tradeoffs, the dynamic behavior, and limitations of the topology are investigated. Furthermore, the round-trip efficiency of the 3P-PPPC for integrating BSS in FCS is compared with conventional FPPC solutions, highlighting the superiority of the proposed topology. A prototype has been built to validate the 3P-PPPC.