A modified adaptive fuzzy control of three-phase active power filter for harmonic compensation

In this paper, a modified adaptive fuzzy control with approximation-error-adaptive capability (MAFCAEAC) is proposed to improve dynamic performance of three-phase active power filter (APF). Firstly, the mathematical model of active power filter with parameter perturbation and unknown external disturbance is established. Then based on the direct adaptive fuzzy control structure, the compensation control term based on the fuzzy approximation error is designed to relax the dependence on the assumption that the fuzzy approximation error is square integrable. The adaptive estimation of the fuzzy approximation error is designed to avoid the high gain and chattering problem caused by the previous compensation items. The parameters are derived from the Lyapunov stability analysis to guarantee tracking performance and stability of the closed-loop system. Simulation studies in the MATLAB/SimPower Systems Toolbox demonstrate that the proposed control methods offer a good behavior in both steady state and transient operation during balanced and unbalanced load.