A Study of Power Quality Regulation Strategies of Energy Storage Converters

High penetration of photovoltaic generation in low-voltage distribution networks often leads to voltage limit violations and increased harmonic distortion. Owing to its four-quadrant output capability, an energy storage converter can be utilized for coordinated mitigation of voltage and harmonic issues. Existing approaches typically allocate fixed converter capacity for voltage regulation and harmonic compensation, which can improve power quality to a certain extent but suffer from limited flexibility. In this study, a power quality management strategy is proposed for energy storage converter. The line impedance at the point of common coupling is first estimated, and corresponding optimization algorithms are then executed based on the impedance and voltage information. Active and reactive power of the energy storage converter are optimally allocated for voltage regulation, while the remaining capacity is utilized for harmonic mitigation. The proposed strategy enhances the flexibility of power quality management, and its feasibility is verified through experimental results.