Design of a Bidirectional CLLC Resonant DC-DC Converter for Energy Storage System

This paper presents a bidirectional full-bridge CLLC resonant DC-DC converter designed for energy storage systems. The converter architecture comprises two sets of full-bridge CLLC resonant converters, configured in a single input double output arrangement. The frequency modulation control is employed to regulate power flow between the battery storage system and the DC bus via the CLLC resonant network. Furthermore, duty control of the primary switches enables individual power handling of each battery module, facilitating voltage balancing among battery modules. To ensure efficient operation, the CLLC resonant topology is employed, guaranteeing zero-voltage-switching (ZVS) across a wide range of power levels, while interleaving operation reduces current ripple. Experimental validation using a 1-kW prototype circuit demonstrates the performance of the proposed DC-DC converter.