MODELING AND SIMULATION OF SOLAR PHOTOVOLTAIC MODULE USING MATLAB/SIMULINK

Abstract

This paper presents the circuit model of photovoltaic (PV) module. Simulation and modeling is done using MATLAB/ Simulink software package. The proposed model is user friendly and can be used as a common platform for both applied physics scientist and power electronics engineers. A detailed modeling procedure is presented. The designed model is verified by using STP255-20/Wd PV module. The IV and PV characteristics are simulated at different temperature and irradiance conditions and the results are verified. The proposed model is very simple fast and accurate. The designed model can be used for analysis of PV characteristics and for simulation of maximum power point tracking algorithms. I. INTRODUCTION Energy is required for large number of purposes. Traditional energy is used from coal, natural gas, oil and nuclear energy. But they are exhaustible and polluting. So we need to find an alternate source which is renewable energy source. This can be more extensively used in many applications. Solar energy is a good option and the electricity produced is clean, long lasting, no moving parts, less maintenance and silent. It has experienced a remarkable growth for the past two decades in its widespread use from standalone and utility interactive PV systems (1, 2). The increase in a number of photovoltaic system installed all over the world brought the need for proper supervision and control algorithms as well as modelling and simulation tool for researcher and practitioners involved in its application is very mandatory. The modelling and simulation of PV have made a great transition and play a vital role in power generation. Simple circuit models have been proposed in literature (3, 4). Even though they are interesting, they are very tedious complicated and impractical. Thus because of numerical challenges, an accurate and comprehensive design of PV system in MATLAB Simulink model is proposed. In this paper modelling is limited to simulation of PV module characteristics. In section II, a simple circuit with detailed circuit modelling of PV module is presented for the design of PV system. In section III, physical equations governing the PV module are presented. A Simulink model is developed for each equation of PV module. In section IV, the numerical result for different temperature and irradiance conditions is presented. Section V presents the discussion and conclusion of the modelling process. II. BASIC CIRCUIT AND MATHEMATICAL MODEL A PV module consists of number of solar cells connected in series and parallel as per the requirement. When solar light falls on PV cell, light energy is converted to electrical energy without any moving parts. The transmitted light is absorbed within the semiconductor, by using this light energy to excite the free electrons from the low energy status to an unoccupied higher energy level. These excess electron hole pairs contribute to the flow of current. A general mathematical description of I-V output characteristics for a PV cell has been researched and analysed for the past four decades. Such an equivalent based circuit based model is mainly used for the Maximum power point tracking techniques (MPPT) (5, 6). Authors (7, 8, 9) discussed about solar power extraction. The equivalent circuit of the general model which consists of a photon current, a diode, a parallel resistor expressing a leakage current, and a series resistor describing an internal resistance to the flow of current is shown in Fig. 1. The current (Ipv) - voltage (Vpv) equation of a solar cell is given by: