MPPT CONTROLLER FOR GRID CONNECTED PV SYSTEM UNDER MISMATCHED ENVIRONMENTAL CONDITIONS

Abstract

The demand for electrical energy is increasing exponentially and conventionally fossil fuels are greatly used to meet that demand. With growing concern about environment, to meet this increased demand, application of Renewable Energy Sources (RES) has been in light. Solar PV has garnered greater attention for power generation among various RES such as wind energy, fuel cells, biogas, and photovoltaic (PV) systems due to its large availability, low maintenance, and pollution-free nature. Solar cells/modules convert solar energy directly into electrical energy. The characteristics of PV depend upon irradiation and temperature. The temperature and the irradiation of the solar cell depend on the atmospheric conditions. As a result, tracking the maximum power point (MPP) in any scenario is vital to achieve that the PV panel produces the maximum possible power. The major goal of this study is to come up with the optimum Maximum Power Point Tracking (MPPT) algorithm for controlling a grid-connected solar PV system under varying environmental conditions. In this work a 700W grid connected solar PV system consisting solar PV array, buck-boost converter, inverter, MPPT controller and inverter control is designed. The modelling and simulation are done in MATLAB/Simulink software. For the proposed system conventional MPPT algorithm- incremental conductance is developed and implemented. The conventional MPPT algorithm- IC have slower speed and high cost; in order to increase the efficiency of tracking intelligent controller is included in the MPPT technique. A fuzzy based maximum power point tracking algorithm is proposed for grid connected solar PV system under mismatched environmental conditions. The fuzzy based maximum power point tracking algorithm is based on a sugeno type fuzzy logic controller with uncertainty handling capabilities. Changes in PV voltage and power are regarded inputs to the fuzzy based controller, while a change in duty cycle is considered the output of the fuzzy based controller. In order to validate the effectiveness of the developed MPPT control, two set of working conditions for analysis such as steady state irradiance and step dynamic change irradiance are considered in MATLAB / Simulink environment. The developed controller is compared with each other in terms of maximum power ratio, transient time, and overshoot.