Multi-port isolated LLC resonant converter for distributed energy generation with energy storage

Distributed energy generation systems with energy storage and microgrids have attracted increasing research interest in recent years. Therefore, multi-ports dc-dc converters have gained more interest. However, when integrating into multiple port converters, the power flow control and ports regulation increase in complexity. In this paper, an isolated multi-port bidirectional converter based on an LLC converter is presented. The converter operates as a dc transformer at a fixed switching frequency and duty cycle without any control loop. The resonant tanks are designed to ensure soft-switching for the whole power range and minimize the voltage variation of the unregulated ports. In order to verify the converter operation, a 1 kW prototype with a 600 V maximum voltage has been implemented.