Research on an LLC Resonant Converter Based on Fractional-Order Capacitor

Breaking through the limitations of integer-order models to enhance the dynamic characteristics of voltage converters has consistently been a crucial research direction in voltage converter studies. This paper proposes a fractional-order capacitor-based LLC resonant converter. The resonant frequency and gain characteristics of the proposed converter are analytically derived and investigated. By adjusting the order of the fractional-order capacitor, both the resonant frequency and voltage gain of the LLC resonant converter can be effectively regulated. Moreover, the proposed converter demonstrates superior capability in suppressing impulse voltage and current during startup, thereby eliminating the need for the conventional soft-start circuit in traditional LLC resonant converters and consequently reducing control complexity. A simulation model of the fractional-order capacitor-based full-bridge LLC resonant converter was developed on the MATLAB/Simulink platform. The simulation results validate the correctness and effectiveness of the proposed converter theory, providing a foundation for optimized control of the converter.