Fractional-order Internal Model Based Frequency Self-adaption Control for Active Power Filter

Precise current tracking is one of the important techniques to ensure the compensation performance of shunt active power filter (SAPF). Repetitive control is favored for its superior steady-state accuracy, but it has the problem of poor adaptability when frequency changes. This paper proposes a fractional-order internal model based frequency self-adaption control strategy. Fractional-order theory is introduced and Lagrange interpolation algorithm is implemented to achieve the superimposed fractional models. Parameter of the fractional delay link is designed and frequency characteristics of different methods are compared. Finally, this paper's strategy is used on a SAPF prototype and experiments are carried out.