A Bidirectional Resonant Converter With Integrated Four‐Switch Buck‐Boost Partial Power Processing

ABSTRACT A bidirectional resonant converter based on partial power processing is proposed in this paper, which meets the charge–discharge characteristic between the energy storage system and high‐voltage DC bus. It has significant advantages such as low loss and a wide voltage gain range. The main power circuit adopts an LLC resonant converter, which works at a fixed resonant frequency as a DC transformer (DCX) to fully leverage the performance advantages of LLC. The partial power processing circuit is integrated with the Four‐Switch Buck‐Boost (FSBB) converter and LLC‐DCX. The proposed converter can not only give full play to the advantages of Pulse Width Modulation (PWM) of FSBB but also give full play to the efficiency advantages of LLC‐DCX. Meanwhile, the partial power circuit can broaden the voltage regulation range of LLC‐DCX while reducing the converter loss. At the end of this article, to verify the feasibility of the theory, a 1 kW experimental prototype is built. The primary voltage is constant at 400 V, and the secondary voltage range is 350–450 V. The forward peak efficiency of the proposed converter is 96.88%, and the reverse maximum efficiency is 96.64%.