A detailed model and control strategy for a three-phase grid-connected PV system: a case study of Oued El Kebrit 15 MWp PV plant

Abstract

The growing integration of photovoltaic (PV) power into the grid has brought on challenges related to grid stability, with the boost converter and the inverter introducing harmonics and instability, especially under non-linear loads and environmental changes. Therefore, conducting practical testing on grid-connected PV systems under various conditions can be difficult and often impossible due to the destructive nature of many scenarios. Existing research often lacks comprehensive modeling, real-world validation, and explicit adherence to grid connection standards. Thus, this paper aims to present a detailed modeling, design, and control strategy for a grid-connected PV system that accurately reflects the behavior of the 15-megawatt-peak (MW_p) PV plant at Oued El Kebrit, Algeria, while adhering to the IEEE 929–2000 and European EN 50160 grid connection standards. The developed one-megawatt model encompasses all components of the double-stage topology, namely the PV array, boost converter, maximum power point tracking (MPPT) controller, three-phase pulse width modulation (PWM), voltage source inverter (VSI), LCL filter, grid synchronization technique with a phase-locked loop (PLL), VSI dual-loop current controller with PI regulators, and other grid connection components. The entire proposed model, implemented in MATLAB/Simulink, was used to simulate various scenarios under different weather conditions, including standard test conditions (STC), a sudden drop in solar irradiation, and a real-world scenario. The simulation and comparison outcomes with real-life data collected from the Oued El Kebrit PV plant showed close alignment with the performance of the actual PV plant; this not only validated the model’s reliability and efficiency but also confirmed its compliance with IEEE and EN standards.