A composite current control method of the three phase shunt active power filter

Aiming at the influence of nonlinear loads on the quality of power grid, a shunt active power filter (SAPF) topology is proposed. According to this topology, the mathematical model of the three-phase shunt active power filter is established. Based on the model, it's transfer function is deduced, and the current controller is designed on account of PI control strategy. By analyzing the limitation of the PI controller in current tracking control method used for active power filters, a composite control strategy combining repetitive control with PI control method is proposed to improve the steady performance of the control system. Experimental results demonstrate that the current control method combining repetitive control with PI control method has a high steady-state compensation accuracy, which can effectively suppress harmonic currents caused by nonlinear loads and greatly improve grid current waveform.