A Multifunctional VSC for Grid Synchronized SPV System with Mode Transfer Capability

Abstract

This work presents a multifunctional VSC (Voltage Source Converter) for a two-stage single-phase distribution network synchronized battery less PV (Photovoltaic) array generating system with seamless mode transfer capability. This system depicts excellent response at load perturbations and ensures electricity to local loads in day time even in absence of the power grid and cloudy days. The hybrid DSC filter algorithm based control prohibits deterioration of the grid power quality at nonlinear loading besides utility network parameter drifts and the grid voltage distortions. The estimated active load current component and in phase grid voltage unit vector are processed together to make the utility network synchronized PV system multitasking.  VSC not only injects surplus power extracted through PV panel to the grid in synchronized mode, but it also provides load harmonics and reactive power compensation.  VSC maintains instantaneous power equilibrium not only in grid tied mode but in an islanded mode too under dynamic conditions. This also ensures sinusoidal load voltage in an islanded mode. The THDs (Total Harmonics Distortions) in the utility network current and PCC voltage are found below 5% in both the modes and in compliance with constraints of the IEEE-519 and the IEEE-929 PQ standards.