A Notch Control Strategy of Energy Storage Converter for Suppressing Grid Harmonics

Harmonic currents introduced by nonlinear loads are prone to cause grid current distortion. However, the conventional filter-based method can only suppress harmonics extracted by the filter, and it is difficult to effectively suppress the harmonics of uncertainty loads, such as coupled harmonics introduced by the pulse load. First, the mechanism of grid current distortion caused by nonlinear loads is revealed based on the impedance model. Then, a notch control strategy is proposed for the energy storage converter, which can significantly reduce the impedance of the energy storage converter and make the optimized converter more like a notch filter. In addition, the impact of the control parameters on the proposed control and the operational limitations of the optimized converter are discussed. Finally, simulation and experimental results verify that the proposed control can effectively suppress broadband harmonics without harmonic extraction filters.