An enhanced repetitive control strategy for shunt active power filter with LCL output filter

This paper presents an enhanced control strategy for three-phase shunt active power filter to improve dynamic response performance without sacrificing steady-state accuracy. The proposed current controller composed of a repetitive controller and a proportional-integral controller connected in parallel, where the repetitive controller only need storage one-sixth of the fundamental period data. In addition, this paper analyses the reasons of delay time in detail, and presents a digital compensation method for the time delay. Experimental results verify the effectiveness of the proposed control strategy.