Fractional Order Sliding Mode CLLC Resonant Converter Based Strategy

CLLC converter serves as a crucial interface for facilitating the bidirectional transfer of energy between electric vehicles and the power grid, which is essential for achieving peak frequency regulation within the grid. This study addresses the challenges associated with the slow dynamic response and inadequate output voltage stability of existing CLLC resonant converters by introducing a fractional-order sliding mode control strategy. A dual closed-loop control system is developed to enhance the dynamic response, stabilize the output voltage, and improve overall system efficiency. The topology of the CLLC resonant converter is thoroughly analyzed to formulate a fractional-order mathematical model. Subsequently, a fractional-order PI controller for the current inner loop and a sliding-mode controller for the voltage outer loop are designed to implement the dual closed-loop control mechanism. The proposed control strategy is subjected to simulation under both startup and soft-switching conditions, with results indicating a significant improvement in the dynamic response capabilities and output voltage stability of the CLLC resonant converter.