Pseudo-Partial-Power Converter without High Frequency Transformer for Electric Vehicle Fast Charging Stations

Abstract

This paper presents a new partial power converter (PPC) for the DC-DC stage of electric vehicle (EV) fast charging stations. The proposed converter handles only a fraction of the total power delivered from the grid to the battery, increasing the overall system efficiency and power density, while potentially reducing the cost of the charger. The proposed topology is based on a switched capacitor between the AC terminals of an H-bridge converter, and does not require high frequency isolation transformers to provide a controllable voltage source between the DC-link and the battery. The proposed concept can be implemented using interleaved power cells, which can improve the power quality, reduce inductor size, and enable scalability for higher power rating chargers. The operating principle, partial operation analysis, control scheme, and simulation results are presented to validate the proposed concept.