MATLAB – Based Software for Modeling and Studying Grid – Tied Photovoltaic Systems

On-grid photovoltaic systems are well known and established systems in countries where solar energy is considered for residential buildings. MATLAB – based interactive software was developed to perform a quick and reliable design of grid – tied photovoltaic systems. The software is one of a kind, since it was the first time to build such a user-friendly comprehensive tool using MATLAB. The reason behind choosing MATLAB as a programming environment was primarily because of its powerful capabilities in numerical computation, data analysis and visualization. MATLAB also offers impressive and easy-to-use tools in applications development using Graphical User Interfaces (GUIs). The software was originally developed to serve educational purposes in the university domain, keeping in mind that MATLAB is considered a standard tool for tackling engineering problems. In the first stage of this project, the software was created by using simple script programming in m-files, and then these m-files were used later on with Graphical User Interface programming. It’s an essential step before installing a PV system, whether it is stand alone or grid-tied systems, to perform a detailed study which showcases its technical and economical feasibility. The technical validity of the PV system can be achieved by insuring that the system is working with a sufficient overall light-to-electricity conversion efficiency. This can be insured by a good selection of the system components such as PV panels, inverters, and cables, connecting the system components in a permissible manner, and a proper installation of the PV arrays in order to increase the sun light exposure and reduce surface temperatures. The software was developed to perform a sequential task designing and planning procedure, which means that the design procedure consists of a number of dependent tasks that follow each other as shown in Figure.1. The software was equipped with a daily 13-year period meteorological database for number of cities in the United Arab Emirates (UAE) and PV system components database (i.e. PV modules, inverters, etc). MS Excel was used to build the databases, due to the simplicity of linking Excel to MATLAB routines and the ease of carrying out adjustments in the databases whenever necessary. The first task in the design procedure is to specify the site information and carry out the solar irradiance study. This is simply done by selecting the city of investigation, specifying the PV installation area orientation and inclination angle, and finally determining a proper reflectivity factor depending on the surrounding ground surfaces and structures (i.e. sand, grass, snow, etc). 6