Abstract

The expansion of electric grid has made the conventional power system to be more prone to power quality issues especially harmonics. The injection of harmonics will lead to generation of poor quality grid current. Conventionally filters are used to avoid such problems, but they are bulky. This paper proposes an improved current controller to provide a high quality grid current under nonlinear loads and voltage distortions. The proposed control scheme uses a combination of proportional integral (PI) controller and repetitive controller (RC) and is employed in synchronously rotating reference frame. The repetitive control gives a simple and practical solution for multiple harmonics compensation. The proposed control does not require local load current measurement and grid voltage harmonic analysis. Thus it can be incorporated into the conventional system without the usage of any additional hardware. It provides better grid current quality compared to that of conventional PI controller. The control strategy is analyzed. Simulation results are presented to validate the feasibility of the proposed controller.