Current loop control strategy research for shunt active power filter

Since traditional PI controller cannot realize zero steady-error harmonic compensation for active power filter. In this paper, two types of output current control strategy composite controller with PI controller and repetitive controller parallel and specified order zero steady-error controller were proposed. Composite controller with PI controller and repetitive controller parallel running improves steady performance since repetitive controller can follow periodic disturbance with zero steady-error, while PI controller ensures rapidly responding. Specified order zero steady-error technology can realize zero steady-error control for single frequency harmonic. Simulation and experiment show these two methods are very useful. However, they should be tested in applications of industry field.