An Efficient Control Scheme Based on PLL Integrated PI Controller for Grid-connected Solar Photovoltaic Systems

Abstract

The market for solar energy is growing these days, thanks to recent developments in Photovoltaic (PV) systems. The integration of solar energy to the grid is required for its optimum utilization. A novel control of a single stage 3 phase grid connected solar inverter is presented in this paper. A PV array, Voltage Source Inverter (VSI) for converting dc to ac, and a filter that connects it to the grid are the major components of the proposed system. The inverter output is regulated with respect to the grid using Synchronous Reference Frame (SRF) control. A 3-phase Phase Locked Loop (PLL) is used to lock the grid frequency and phase in relation to inverter output voltage. The Perturb and Observe (P&O) algorithm is used to obtain the reference voltage corresponding to the maximum PV power. To remove the high frequency harmonics, the inverter output is combined with an LCL filter. The dynamic performance of the proposed system under the number of stochastic environmental conditions are validated using MATLAB Simulink platform.
 HIGHLIGHTS
 
 The proposed PLL integrated PI controller provided high robustness under stochastic environmental conditions
 Enhanced system dynamic performance and accurate MPP tracking
 The inverter output is free from the high frequency harmonics
 Improved control performance
 
 GRAPHICAL ABSTRACT