A novel voltage regulation technique for a three phase grid connected photovoltaic system using fuzzy fractional order pi controller

Abstract

Since past few years the density of the grid connected photovoltaic (PV) systems is increasing to meet the additional demand for electricity. The usage of renewable energy sources is encouraged by various government organizations by giving incentives, thus leading to reduction in the fuel imports, saving foreign currency, protecting the environment from pollution by avoiding burning of coal and increasing the reserves of the fossil fuels. Challenges are also increasing proportionately with increase in number of the grid connected PV systems and one of them is voltage regulation. Irrespective of solar insolations, PV cell operating temperatures and loading conditions, the voltage has to be maintained within the prescribed limits as per the standards. Different methods of controllers for voltage regulation are available in the literature. A novel fuzzy fractional order proportional plus integral (FFOPI) controller is proposed in this paper for voltage regulation of the grid connected PV systems. The proposed FFOPI controller combines two techniques, a fuzzy logic controller (FLC), which further regulates a fractional order proportional plus integral (FOPI) controller. The effectiveness of the proposed methodology is illustrated by simulating the proposed FFOPI controller for voltage regulation of a grid connected photovoltaic system in Matlab/Simulink. The performance of FFOPI is compared with integer order proportional plus integral controller (IOPI) and FOPI controller. The simulation results reveal that the proposed FFOPI controller outperforms the IOPI controller and FOPI controller performance.