Decoupling and Control of Real and Reactive Power in Grid-Connected Photovoltaic Power System

The paper presents a detailed modeling and simulation of different control schemes of the real and reactive power flows in a three-phase voltage source inverter (VSI) interfacing a photovoltaic (PV) generation system to the power grid. Synchronisation of the inverter and grid AC waveforms is achieved using a phase-locked-loop (PLL) circuit. An effective decoupling strategy based on proportional-integral (PI) controllers is designed to eliminate the interaction between the two current components. Finally, the influence of the grid disturbances on the PV system and the influence of the solar energy intermittency on the power grid have been tested. The overall model is implemented in Matlab and Simulink/SimPowerSystems toolboxes. Simulations results with the PV system operating with real irradiance data will be presented to demonstrate the performance of the proposed decoupling and control strategies under different conditions of the power grid