An ESR Quasi-Online Identification Method for the Fractional-Order Capacitor of Forward Converters Based on Variational Mode Decomposition

An quasi-online equivalent series resistance (ESR) identification method that considers the impact of capacitance based on variational mode decomposition (VMD) of forward converters is proposed in this paper. Firstly, the capacitance impact is included in ESR derivation. Subsequently, VMD is adopted to process characteristic signals for harmonic analysis, filter out noise and simplify circuits design. The experiments and simulation are employed to verify the proposed method. In addition, in order to overcome the disadvantages of using ideal capacitors in traditional simulation, fractional-order capacitors are constructed to describe the non-ideal characteristics of the capacitor. Meanwhile, the identification result is compared with the LCR meter measurement. Thus, the superiority of the proposed ESR quasi-online identification method and the construction method of fractional-order capacitors are confirmed through comparative analysis.