Resonant and Quasi-Z Source based Multiport Converter for High Power EV Fast Charging with Full and Partial Power Processing

In this paper, two new multiport converter (MPC) topology have been designed for fast-charging electric vehicles (EVs), integrating the grid, battery energy storage system (BESS), and EV charging. By using both Full Power Processing Converter (FPPC) and Partial Power Processing Converter (PPPC) configurations, the proposed design reduces size and costs, leveraging features like a quasi-Z-source converter (qZSC) for the BESS and a series resonant converter (SRC) for EV charging. The qZSC helps to boost BESS voltage, enabling bi-directional energy flow between grid and BESS, which can store energy during offpeak times and discharge to the grid or EVs during peak demand, supporting grid stability. Additionally, the PPPC configuration allows partial power to flow directly from BESS to EV, further reducing cost by lowering converter rating, reducing losses, ensuring galvanic isolation, and meeting safety standards. A prototype of 550 W has been built to validate the proposed converters.