An EAFOGI-FLL Based Adaptive Control for Seamless Operation of a Solar Photovoltaic System

This paper presents an enhanced adaptive fourth order generalized integrator with frequency locked loop (EAFOGI-FLL) based control that improves the power quality of a solar photovoltaic system (SPVS) in grid-connected mode (GCM) and standalone mode (SAM), ensures seamless operation, makes the grid currents sinusoidal and, also eliminates DC offset. It ensures unity power factor (UPF) operation of the grid to minimize line losses. The control maintains the point of common coupling (PCC) voltages sinusoidal in GCM and SAM even in the presence of nonlinear loads. The FLL enables effective frequency tracking with grid frequency variations and makes the system adaptive. The SPVS is run in maximum power point tracking (MPPT) mode in GCM and, with an improved control in SAM to ensure power balance. The system is analyzed using a developed simulink model in different conditions.