An enhanced repetitive current control strategy for three-phase shunt active power filter

In this paper, an enhanced repetitive control strategy is proposed to improve the performance of shunt APF, which consists of a repetitive controller and a proportional-integral (PI) controller. The proposed repetitive controller directly combines with the equivalent closed-loop transfer function of the traditional PI feedback control. The steady-state performance and the dynamic response to load variations have been significantly improved compared to conventional control methods. The proposed control strategy is mainly to compensate harmonic currents, meanwhile, as well as compensation reactive-power and balanced three-phase supply currents. The effectiveness of the proposed control strategy is verified through experimental results.