Performance analysis of PLL control strategies on grid connected PV system under disturbed grid conditions

Abstract

The rising demand for renewable energy, particularly solar power, stems from its immediate availability and the imperative to curb carbon emissions associated with fossil fuel consumption. Consequently, there has been a significant surge in the installation and development of grid-connected Photovoltaic (PV) systems. However, integrating PV sources with the grid presents various challenges related to power quality. This article aims to explore how grid-connected PV systems perform when faced with different disruptions within the grid. To address this, a novel Dual Sliding Fourier Transform (DSFT) Phase-Locked Loop (PLL) control strategy has been proposed. The methodology involves modeling a typical grid-connected PV system. The proposed and conventional control strategies to regulate the grid-connected inverter have been implemented under four distinct disturbed conditions: frequency disturbance, harmonic disturbance, phase jump disturbance, and DC offset disturbance. This approach is further compared with the traditional techniques, namely Dual Second Order Generalized Integrator (DSOGI PLL) and decoupled stationary reference frame (d?? PLL). The evaluation criterion considers the time required to track frequency changes, mitigation of harmonics, and accuracy in phase error estimation. The findings reveal that the DSFT PLL control strategy outperforms the conventional techniques across all four disturbed conditions in the context of grid-connected PV systems.