Pre-Synchronization Virtual Synchronous Generator Grid-Connection Strategy Based on Fuzzy Active Disturbance Rejection for Photovoltaic Storage

ObjectivesVirtual synchronous generator (VSG) technology is extensively utilized for its capability to regulate damping and inertia during inverter grid connection. However, line impedance is commonly present, and voltage and current distortions are prone to occur during the pre-synchronization process of disconnection and grid connection. Therefore, the control structure and pre-synchronization method of VSG are optimized.MethodsA photovoltaic power generation system and hybrid energy storage are used to replace a traditional DC source, simulating actual conditions. Virtual active power and virtual current are incorporated into the conventional VSG model to compensate for phase and amplitude differences during grid connection, thereby achieving frequency and voltage regulation. To address the issue of selecting PD control parameters in a traditional linear active disturbance rejection control (LADRC) system, fuzzy control is employed to adaptively adjust these PD parameters online. Furthermore, LADRC is introduced into the active power loop for secondary frequency regulation, which enhances system robustness.ResultsThe feasibility of the proposed method is verified through MATLAB/Simulink simulation, which demonstrates the excellent performance of the pre-synchronization control system.ConclusionsThe fuzzy LADRC enables rapid and smooth grid connection, suppresses grid-side current surges, and reduces frequency oscillations, thereby improving the stability of the grid-connected inverter-grid interaction system.