An enhanced current control strategy for three-phase shunt active power filters with repetitive controllers

This paper proposes an enhanced current controller for three-phase shunt active power filters (SAPFs). The proposed current controller is composed of a proportional-integral (PI) controller and two repetitive controllers (RCs) where the RCs are designed with a delay time of one sixth of the fundamental period (T/6). With the combination of these RCs, the SAPF can offer a good harmonic compensation performance under various types of nonlinear loads (three-phase or single-phase nonlinear loads). As consequence, the supply current is effectively compensated to be sinusoidal despite the nonlinear load current. In addition, the proposed SAPF also can provide a fast dynamic response under load variations to maintain the supply current sinusoidal. The effectiveness of the proposed controller is verified through simulation results.