Design and Analysis of Grid-tied PV Power conditioning System Through LCL filter based on Capacitor Current Active Damping with Positive Output Virtual Impedance

In the grid-tied PV inverter systems, the design of a proper power conditioning system is an important issue to ensure high-quality power injection to the grid. In the low-voltage distribution network, the grid impedance variations change the resonant frequency of LCL filters. The capacitor current feedback active damping is one the most effective procedures to suppress the resonance of LCL filters. In this paper, A proportional-integral (PI) capacitor current feedback active damping method with positive virtual impedance shaping is proposed. Utilizing the proposed control strategy, the stability of the grid-tied PV inverter system against changes in grid impedance is well maintained. In addition, the system offers good performance against the PV power variations. In order to track the maximum power point, the incremental conductance (IC) procedure along with an integral regulator is utilized. Simulation of the overall system also includes solar panels, maximum power point tracking algorithm, DC-DC boost converter as well as an inverter, and LCL filter to model the grid-tied PV system with the most possible details. Simulations are carried out in MATLAB/Simulink, and it has been proved that the proposed control system maintains its stability against grid parameters variations.