Control of Three-Phase Inverters for Smart Grid Integration of Photovoltaic Systems

Abstract

This paper provides a smart photovoltaic (PV) inverter control strategy. The proposed controllers are the PV-side controller to track the maximum power output of the PV array and the grid-side controller to control the active and reactive power delivered to the electric grid through the inverter. A Volt-VAR regulator is proposed for controlling the reactive power exchange with the grid according to the voltage at the point of common coupling (PCC). The gains of the proposed proportional-integral (PI) controllers are optimized using a genetic algorithm (GA) via adaptive online tuning. The control methodology is then tested to a 33-bus radial distribution network under MATLAB/SimPowerSystem environment to prove the validity of the proposed control methodology and to analyze the interactions between the PV-based distributed generation (DG) and the power network. The optimal control of PV inverters demonstrated that the optimized Volt-VAR control strategy is both efficient and effective. The optimization of the PI controller parameters resulted in a good dynamic response under varying climatic conditions. The proposed control method enables the most efficient utilization of PVDG systems by extracting maximum power and contributing to grid voltage support.