Energies, Vol. 18, Pages 4066: Enhancement of Power Quality in Photovoltaic Systems for Weak Grid Connections

Energies, Vol. 18, Pages 4066: Enhancement of Power Quality in Photovoltaic Systems for Weak Grid Connections

Energies doi: 10.3390/en18154066

Authors:
Pankaj Kumar Sharma
Pushpendra Singh
Sharat Chandra Choube
Lakhan Singh Titare

This paper proposes a novel control strategy for a dual-stage grid-connected solar photovoltaic (PV) system designed to ensure reliable and efficient operation under unstable grid conditions. The strategy incorporates a Phase-Locked Loop (PLL)-based positive sequence estimator for accurate detection of grid voltage disturbances, including sags, swells, and fluctuations in solar irradiance. A dynamic DC-link voltage regulation mechanism is employed to minimize converter power losses and enhance the performance of the Voltage Source Converter (VSC) under weak grid scenarios. The control scheme maintains continuous maximum power point tracking (MPPT) and unity power factor (UPF) operation, thereby improving overall grid power quality. The proposed method is validated through comprehensive simulations and real-time hardware implementation using the OPAL-RT OP4510 platform. The results demonstrate compliance with IEEE Standard 519, confirming the effectiveness and robustness of the proposed strategy.