7 Simulation of PV Systems Under Normal and Partially Shaded Conditions Reshma Gopi R. 1 , Sreejith S 2 1 Research Scholar, 2 Associate Professor SELECT, Vellore Institute of Technology, Vellore, India International Journal of Research in Electrical & Electronics Engineering Volume 3, Issue 1, January-March, 2015, pp. 07-17 ISSN Online: 2347-5439 Print: 2348-0025, DOA : 09032015 © IASTER 2014, www.iaster.com ABSTRACT This paper deals with mathematical modeling and simulation of a photo voltaic cell under normal (without partial shading) and partially shaded conditions to analyze its electrical characteristics. The maximum power that could be generated by a PV System depends on temperature and irradiance variations. The maximum power increases as the irradiance increases and vice versa. While, maximum power decreases as the temperature increases. In order to obtain full utilization from the PV array, it is necessary to analyze the characteristics of PV System. The simulation has been performed through Matlab/Simulink environment. This paper also discusses boost converter design, its simulation and output characteristics. Keywords: Maximum Power Point Tracking, Photovoltaic cells, DC-DC Converter, Choppers, Inverters, pulse width modulation, Partial Shading. 1. INTRODUCTION Photovoltaic (PV) generation gained increased importance as a renewable energy sources due to factors such as worldwide increase in energy demand, simplicity of allocation, absence of fuel cost, low maintenance, lack of noise, lack of wear due to the absence of moving parts, longer life, absence of pollution, less time for installation, highly mobile and portable parts and output power capability to match peak load requirement. [1], [2].Solar powered Systems generate electricity using Photovoltaic cells, which converts light energy directly into electrical energy. PV systems can be either stand alone or connected to utility grid [11]. Photovoltaic cells are combined to make modules that are enclosed in glass or plastic. Materials used in solar cells are Monocrystalline Silicon module and Polycrystalline Silicon module. In general, PV generation systems have two major problems; the conversion efficiency of electric power generation is low (in general less than 17%, especially under low irradiation conditions), and the amount of electric power generated by solar arrays changes continuously with weather conditions [10]. The PV arrays found applications such as battery charges, solar powered water pumping systems, solar hybrid vehicles and satellite power systems[1],[8]. A circuit based approach has been used by many researchers to analyse the characteristics of PV module to extract maximum power. PV systems have to operate at their maximum power point for better utilization [7]. Photovoltaic power varies with insolation, temperature and load characteristics [3], [5], [6]. Photovoltaic power is directly proportional to irradiance and inversely proportional to temperature [12],[17]. Circuit based approaches like one diode model and two diode model cannot be used when irradiance is nonuniform [15], [16].This paper discusses a mathematical model to discuss the characteristics of PV system.