EFFECT OF TEMPERATURE AND IRRADIANCE ON THE ELECTRICAL PERFORMANCE OF A PV MODULE

Usha Mandadapu 1 , S. Victor Vedanayakam 1 and K. Thyagarajan 2 . 1. Department of Physics, Madanapalle Institute of Technology and Science, Madanapalle. A.P. India. 2. Department of Physics, JNTUCEP. Pulivendula, A.P. India. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History

Solar cells are the devices, which convert the solar radiation into the electrical energy without effecting the environment . To predict the real behavior of solar cells like changes in maximum power, short circuit current and open circuit voltage by changing the temperature and irradiance can be studied by using the MATLAB (simulation model). In this paper, a single diode MATLAB model is used to study the changes in solar PV module by varying temperature (100C,200C,300C) and by varying the irradiance(400W/m2, 600W/m2, 800W/m2). To study the changes in electrical parameters of a solar PV modules KD330GX-LFB and KD325GX-LFB experimental data sheet are taken and the results are discussed in the conclusion.

…………………………………………………………………………………………………….... Introduction:-
The continuous use of fossil fuels for industrial purpose leads to huge damage to eco system and living conditions. To sustain our earth, the mankind has to decrease the green house gases like CO 2 ,Methane..,by choosing alternatives to fossil fuels. In order to conserve natural living spaces and not to harm the next generation utilization of renewable energy should increase. Among all the renewable energy sources, solar energy is having the large potential and small amount of it is utilizing for various purposes. Photovoltaic Effect converts solar energy to the electrical energy. Widely used applications of PV system are water heaters, street lights, electric vehicles, military and space applications (1,2). Solar panels and modules are works on the principle of Photo voltaic effect, and generates the electric power. These PV modules and panels are largely effected by different weather conditions. In this paper, mainly modeling parameters are explained. By changing the temperature of a simulink PV module, the changes in output parameters are observed. The simulated results are compared with the KD330GX-LFB, KD325GX-LFB experimental results. 2019 Tarak Salmi , Mounir Bouzguend, Adel Gastli, Ahmed Masmoudi developed solar PV module using basic semiconductor equations and they studied the performance of solar PV module under various atmospheric conditions(6). Jay Patel and Gaurang Sharma studied the characteristics of a module, they observed the solar cell performance under various temperature and irradiance conditions (7).

Characteristic I-V equation:-
The I-V equation of a solar cell, which represents the output of a solar cell is described by few researchers from past four decades (8). The solar cells is generally represented by the single diode due to its simplicity in computational time. The Single diode solar cell can be modeled using the electrical components current source, parallel resistor, series resistor.
The single diode photovoltaic I-V equation (8) = cell temperature at STC:25+273 =Coefficient of temperature of short circuit current (A/K).

Reverse Saturation Current:
In solar cell, the reverse saturation current is produced due to the diffusion of charges from n-side to p-side and p-side to n-side. The equation for Io is given from the literature as Tc= Standard temperature.
Ideality factor: The ideality factor gives us how closely the diode follows the ideal diode equation, the ideality factor is material dependent Some of the researchers like Bashahu and Nkunbabakura (12) used different methods to identify, ideality factor and suggested that it lies between 1.26 to 1.5 and "n" is assumed to be independent of temperature and solar radiation (10).   The temperature change of KYOCERA KD330GX-LFB is observed for the temperatures 10 0 C, 20 0 C, 30 0 C and the changes in P max, V mp, Imp, Voc, I sc are taken from the I-V , P-V graphs and those values are tabulated. The resistances for KD330GX-LFB simulink model are identified using the Newton_Rapshon method those values are Rp=493.206 ohm and Rs=0.2500.
By Varying Irradiance: Solar module efficiency depends upon the input variable irradiance, as the irradiance is changed from 400W/m 2 to 800W/m 2 the output efficiency of a module changes .To study the changes in the performance of a solar PV module, KD330GX-LFB and KD325GX-LFB are studied and the results are tabulated.     Table -2 and Table-4 represents the change in efficiency and fill factor, from those We can conclude that as, the temperature increases the efficiency decreases ,This is because of increased intrinsic recombination. By the increase of heat energy , band gap of semi conductor decreases the open circuit voltage which is a function of band gap, decreases faster than the increase in the short circuit current so it leads to the decrease in the efficiency. The negative temperature coefficient of Silicon material reveals that as the temperature increases, the maximum power output decreases. The Table-5 and Table-7 represents the changes in the parameters of solar cell with the change in the irradiance. The Table-6 and Table-8 represents the changes in the efficiency and fill factor with the changes in the irradiance. As the irradiance increases, the number of photons incidenting on the module produces maximum power and leads to increase in the efficiency . This generalized simulink model is used to study the changes in the output parameters of any photovoltaic module by using Newton-Rapshon numerical method to identify the suitable resistances.