Grid Connected System for Two-stage Solar Photovoltaic Based Stand-Alone Scheme Having Battery as energy storage

Abstract

Stand alone renewable energy based on photovoltaic systems accompanied with battery storage system are beginning to play an important role over the world to supply power to remote areas. The objective of the study reported in this paper is to elaborate and design a bond graphs model for sizing standalone domestic solar photovoltaic electricity systems and simulating the performance of the systems in a tropical climate. The systems modelled consist of an array of PV modules, a lead-acid battery, and a number of direct current appliances. This paper proposes the combination of lead acid battery system with a typical stand alone photovoltaic energy system under variable loads. The main activities of this work purpose to establish library graphical models for each individual component of standalone photovoltaic system. With solar customers in many states now receiving a low price for electricity sold back to the grid, battery back-up systems can be a viable alternative as they use the electricity stored during the day to run your house at night. They also have the advantage of being able to supply power during power outages.Grid-connected systems do not need batteries which reduces considerably initial capital costs and energy costs. For a comparable load, grid-tied systems use smaller PV arrays than stand-alone systems. In order to address this issue, a two-stage stand-alone scheme consisting of a novel transformer coupled dual-input converter (TCDIC) followed by a conventional full-bridge inverter is proposed. The proposed TCDIC can realize maximum power point tracking and battery charge control while maintaining the proper voltage level at the load terminal. A suitable control strategy for the proposed TCDIC devised for manipulating the TCDIC to realize the first two aforementioned objectives, while the third objective is achieved by employing a conventional proportional integral (PI) controller to control the output voltage of the full bridge inverter through sinusoidal pulse width modulation. The simulation results are performed by using Matlab/Simulink software.