Three-Phase Interleaved Bidirectional LLC Resonant Converter for High-Efficiency PV-Battery Energy Storage Systems

Bidirectional DC–DC converters that offer high efficiency, galvanic isolation, and dependable operation across a broad voltage range are necessary for residential photovoltaic–battery energy storage systems. Conventional methods, such as dual-active-bridge (DAB) converters and non-isolated buck-boost converters, have drawbacks in terms of reduced efficiency under partial-load conditions, circulating current losses, and safety requirements. A three-phase interleaved bidirectional LLC resonant converter for home PV-battery applications is proposed in this paper. In order to guarantee consistent resonant behavior and soft-switching operation in both charging and discharging modes, the suggested architecture makes use of a symmetrical LLC structure. Interleaving is used to improve thermal performance, lower current ripple, and increase power scalability. A passive current balancing technique based on flying capacitors is presented to address current imbalance across phases, allowing automated current sharing without the need for extra sensors or intricate control schemes. The basic harmonic approximation is used to assess the converter's working principle, and a frequencybased control plan is put into place to manage bidirectional power flow. MATLAB/Simulink simulations and laboratory prototype testing are used to validate the suggested system. The suggested converter's appropriateness for home energy storage applications is confirmed by the findings, which show steady operation, efficient current sharing among phases, and high conversion efficiency.