Analysis of optimized phase locked loop for grid synchronization of solar PV system under grid disturbances

Abstract

AbstractIn this work, an optimal phase locked loop (PLL) is employed to estimate the fundamental grid frequency and phase angle under grid disturbances, which largely reduces the frequency and phase error. Conventional synchronous reference frame (SRF) offers considerable results for balanced grid conditions but has poor performance under grid disturbances with improper phase detection. In this regard, gravitational search algorithm (GSA)‐based optimization is utilized to optimally tune the proportional and integral (PI) gain values of conventional SRF PLL, which ensures the proper tracking of fundamental phase angle and frequency even during abnormal grid conditions, that is, voltage unbalance, frequency variations, high‐frequency harmonics, and phase variations. Further, integral square error (ISE) criteria, settling time, and overshoot are considered as objective functions to obtain the optimal value of current gain, present in the control loop of a grid‐tied solar photovoltaic (PV) system. The supremacy of the proposed work, compared to SRF and optimal SRF PLL, is tested with MATLAB®/Simulink studies and verified by dSPACE‐1104‐based hardware‐in‐loop (HIL) results for real‐time validation.