In view of the increasingly serious situation of power grid harmonic pollution

the traditional repetitive control is improved from the perspective of the resonant controller to ameliorate the steady-state compensation accuracy and dynamic response performance of an active power filter (APF). The optimal repetitive control parameters are obtained for the control object. In order to overcome the dynamic performance deficiency of one-cycle response delay in the repetitive control

an error iteration proportional-integral (PI) control is proposed for ensuring the steady-state accuracy as far as possible while improving the dynamic response speed. Finally

the embedded form of repetitive control is improved. By setting an order feed-forward channel

the structure of improved composite control is optimized. Experiment and simulation results have verified the accuracy and effectiveness of the control strategy proposed.