Abstract

The large-scale integration of photovoltaic (PV) generation introduces critical challenges for power systems, including voltage stability issues and increasing requirements for reactive power compensation. To address these challenges, PV inverters can be operated as Distribution Static Synchronous Compensators (D-STATCOM) to simultaneously supply active power and provide ancillary reactive power support. This paper proposes a control strategy for grid-connected PV-based D-STATCOM systems that incorporates a Fuzzy-PI controller for DC-link voltage regulation and a Dual Second-Order Generalized Integrator Phase-Locked Loop (DSOGI-PLL) for accurate phase angle detection. The Fuzzy-PI controller improves DC-link voltage regulation by adaptively tuning PI controller parameters and surpasses the complexity in mathematics design of conventional PI controller with the robustness of fuzzy logic principles. Meanwhile, the DSOGI-PLL enhances synchronization performance under unbalanced or distorted grid conditions, ensuring reliable current control in the synchronous reference frame. Simulation studies conducted in MATLAB/Simulink demonstrate that the proposed approach achieves the following outcomes: stable active power delivery, superior DC-link voltage regulation (following neatly reference signal and stabilizing under grid voltage variations), and effective compensation of local demands and grid support of reactive power under voltage contingencies. These results highlight the feasibility and improved performance of integrating advanced control methods of which archivable by the proposed control model into PV-based D-STATCOM configurations for modern distribution networks.