Suppression of parameter perturbation in active power filter based on sliding mode control

In order to avoid deviding the system model of the shunt active power filter which is developed in the synchronous dq reference frame into two separate loops, an unified control strategy used for harmonic current tracking and dc link voltage stability of the shunt active power filter is presented and realized by the sliding mode variable structure control. By analyzing the stability of the Lyapunov function, the robustness of the shunt active power filter is derived and the stability condition of sliding mode is presented. The method characterizes suppression to parameter perturbation. Finally, the simulation results show that the presented method is simple to be designed, easy to be realized, and exhibits strong robustness and good dynamic characteristics.