Low Voltage Ride-Through and Arctangent Based VSC Control for High Gain Multiple PV Arrays Coupled to the Grid With Improved Power Quality Platform

This paper presents a grid-tied solar photovoltaic (PV) system designed to manage active and reactive power flow during normal and unbalanced voltage sag conditions while catering to non-linear load demands. Under normal voltage at the common point of connection (CPC), the PV system achieves unity power factor (UPF) operation by meeting active and reactive power requirements, with PV arrays operating at maximum power point (MPP) using the perturb and observe (P&O) algorithm. During unbalanced and voltage sags, the system employs a novel arctangent-based modified least mean square (AM-LMS) algorithm to maintain grid support and prevent overrating of the voltage source converter (VSC). This is achieved by curtailing the active power of one PV array through non-MPP operation and delivering reactive power to the grid in compliance with IEEE-1547-2018 standards. The AM-LMS algorithm provides fast convergence, adjustable step-size parameters, reduced computational burden, and robust control under normal and abnormal grid conditions. The system's ability to balance dynamics and steady-state performance minimizes grid current total harmonic distortion (THD) and ensures low-voltage ride-through (LVRT) capability. The proposed solution is modelled and analysed in MATLAB/Simulink and validated in real-time using OP4510 hardware. Results demonstrate effective utilization of installed PV capacity for grid support, enhanced power quality, and reliable VSC operation, making it a robust solution for modern grid-tied PV applications. The main findings of the work are good utilization of installed PV powers for the grid support during LVRT, effective fast convergence control of VSC with less burden on controller with power quality and prevent over rating operation of VSC during any grid support feature.