Impedance Modeling and Analysis of PV Inverters Considering Fractional‐Order Characteristics of Elements

ABSTRACT Concerning the fact that the inductors and capacitors are of fractional order, this paper establishes the impedance model for fractional‐order LCL‐type photovoltaic inverter based on the harmonic linearization method and verifies the correctness of the fractional‐order impedance model through simulation. The impedance characteristics of the inverter‐side inductor, grid‐side inductor, and filtering capacitor under different orders are also analyzed. The impedance criterion studies the system's stability of the fractional‐order element at different orders, and the suitable fractional‐order element is selected for hardware‐in‐the‐loop experiments based on the analysis results. The findings of the experiment demonstrate that the stability of the inverter is influenced by the order of its fractional‐order elements and that the stability of the system made up of the chosen fractional‐order elements is superior to that of the integer‐order system.