OPTOELECTRONIC MODELING OF SOLAR PHOTOVOLTAIC SYSTEM FOR RURAL ELECTRIFICATION USING MATLAB

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1 International Journal of Electrical and Electronics Engineering Research (IJEEER) ISSN: X Vol.2, Issue 1 Mar TJPRC Pvt. Ltd., OPTOELECTRONIC MODELING OF SOLAR PHOTOVOLTAIC SYSTEM FOR RURAL ELECTRIFICATION USING MATLAB S.M. ALI, BISHNU PRASAD SAHU & STHITAPRAJNA RATH School of Electrical Engineering, KIIT UNIVERSITY, Odisha drsma786@gmail.com bishnu2u@gmail.com sthitaprajna.rath@gmail.com ABSTRACT Maximization of power from a solar photovoltaic module is of special interest for providing electrification to the rural people of Orissa. Optical phenomenon is adopted for achieving maximum power from the solar photovoltaic module as the efficiency of the solar photovoltaic system is very low. In the present work we analyze the design using the basic circuit equations of solar photovoltaic system including the seasonal effects of solar irradiation. Comparisons of solar photovoltaic systems with an improved model has been tested and performed through the help of Matlab and the results are displayed in this work. KEY WORDS - Solar photovoltaic cell; diffraction; total internal reflection; Matlab. 1. INTRODUCTION With the emerging use of renewable energy sources, photovoltaic power generation is used in many applications. Conventionally photovoltaic power generation is consisted of solar photovoltaic arrays and electric converter. Photovoltaic array formed by series/parallel combination of photovoltaic solar modules. The photovoltaic cell is a specially designed p-n junction or Schottky

2 21 Optoelectronic Modeling of Solar Photovoltaic System for Rural Electrification Using Matlab barrier device. The well-known basic diode equation describes the operation of photovoltaic cell. When the cell is illuminated, electron-hole pairs are produced by the interaction of the incident photons with the atoms of the cell. The electric field created by the cell junction causes the photo-generated electron-holes pairs to separate, with the electrons drifting into p-region. The maximum power can be achieved by incidenting more radiation on it. In this paper a new approach has been developed to increase the amount of radiation on the solar cell. 2. SOLAR PHOTOVOLTAIC MODELLING 2.1 BASIC EQUATIONS OF SOLAR CELL A solar cell can be represented by an equivalent circuit shown in Fig. 1 based on the electronics theory. I c R se + I ph I d I sh R sh V - Figure 1 : Equivalent circuit of single solar cell The symbols in Figure 1 are defined as follows: I ph : photocurrent I d : current of parallel diode I sh : shunt current I c : output current V: output voltage R sh : parallel resistance R se : series resistance

3 S.M. Ali, Bishnu Prasad Sahu And Sthitaprajna Rath 22 The I-V equation of Fig.1 is given in equation (1):-- Ic=Iph-I 0 {exp[ ]-1}- (1) The symbols used in equation (1) are I 0 : reverse saturation current q: electron charge( ) A: curve fitting factor K: Boltzmann constant Considering the photocurrent as short circuit current and under the power condition the equation becomes (2) Where V m and I m are maximum power point voltage and current respectively. The value of C 1 and C 2 given as (3) And the value of C 2 is obtained as ) (4) The three equations (2),(3),(4) are the basic equations and these equations are used in formulating the photovoltaic module. 2.2 MODELLING OF IMPROVED SOLAR PHOTOVOLTAIC MODULE Along with the usage of basic equations modeling of improved solar cell involves the usage of optical phenomenon like diffraction and total internal reflection as well as refraction. The solar photovoltaic module is covered within

4 23 Optoelectronic Modeling of Solar Photovoltaic System for Rural Electrification Using Matlab a glass cover with vacuum in the upper side of the solar panel and a glass grating of refractive index 1.52 and is placed across the length of the solar panel. The specifications of grating are 720 grooves per mm and blaze angle is Figure 2 : Design of Improved Solar Photovoltaic Module The diffracted angle of solar radiation through the glass grating can be calculated as β = (5) The symbols used in equation (5) are m: diffraction usually 2 λ: wavelength of light d: grooves per mm α: incident angle When the light strikes from the grating element, it makes an incident angle that satisfies the Snell s laws of refraction with its refracted angle greater than 90 0 and hence reflected totally from the surface of the glass chamber and strikes the solar photovoltaic module thereby increasing the amount of solar radiation.

5 S.M. Ali, Bishnu Prasad Sahu And Sthitaprajna Rath 24 The glass chamber itself acts as a protective membrane to the solar module from natural calamities and helps in increasing the amount of radiation on the solar module. 3. TESTING 3.1 Site Description Odisha which is the 8th largest (155,820 km 2 ) state in India has population of 36,706,920.Due to the unfavourable geographical features the people of Banki of Odisha receives lacks electric power. The area is 30km from Cuttack that lacks a proper electrification plan. The village stretches 950m from north to south and 1250m from east to west with a total area of around 1, m 2. The village population consisted of people per village and mainly agriculture is their means of livelihood. 3.2 Determination of Solar Radiation Estimated of average solar radiation: (6) Where Hav=monthly average horizontal solar radiation Ho=average monthly insolation at the top of the atmosphere a & b are the empirical constant depending upon climate and location. The formula for calculating the average insolation on the earth atmosphere can be calculated as (7) Where, φ=latitude angle of the location δ=declination angle

6 25 Optoelectronic Modeling of Solar Photovoltaic System for Rural Electrification Using Matlab ω=sunrise hour angle Average monthly solar radiation in kwhr/m 2 /day is shown below Table 1 : Solar Radiation Month Solar Radiation January 3.47 February 3.88 March 4.34 April 4.66 May 4.77 June 4.78 July 4.76 August 4.68 September 4.43 October 4.00 November 3.55 December LOAD DETERMINATION The total basic load demand for the villager s of Banki is estimated and shown below:--

7 S.M. Ali, Bishnu Prasad Sahu And Sthitaprajna Rath 26 Table 2 : Estimation of Load Demand Load Number Wattage(W) Usage (Hours/Day) Load(Wh) Televisions Fan Cfl Cfl SOLAR PHOTOVOLTAIC MODULE MODEL IN MATLAB A 175W PV module BP4175B was chosen for modeling in MATLAB. The PV module have 72 series connected monocrystalline 5 silicon cells. The concerned electrical characteristics specifications are shown in table 3. Table 3 : Electrical Characteristics of Solar Array Parameter Variable Values Maximum power Pm 175W Voltage at pmax Vm 35.4V Current at pmax Im 4.94A Short circuit current Isc 5.45A Open circuit voltage Voc 43.6V Temperature coefficient of Isc A (0.065±0.015)%/ 0 C The PV module was implemented in MATLAB using the equations had been presented in previous sections. The obtained characteristics graph for different months is shown below.

8 27 Optoelectronic Modeling of Solar Photovoltaic System for Rural Electrification Using Matlab Figure 3 : Power Voltage Graph Figure 4 : Current- Voltage Graph 3.5 COMPARISON OF IMPROVED SOLAR PV MODULE WITH GENERAL SOLAR PV MODULE The experiments for this paper were carried out under bright and sunny weather. The data, thus obtained are graphically summarized and illustrated below:--

9 S.M. Ali, Bishnu Prasad Sahu And Sthitaprajna Rath 28 Figure 5 : Maximum Power Versus Months Of The Year 3.6 IMPROVED SOLAR PV SYSTEM BUIT FOR ANALYSIS In most of the rural electrification, solar photovoltaic systems place an important role where the improved solar array is connected to the energy storage system i.e. battery. The array output in excess of load requirements is used to charge the battery. If excess power is still available after fully charging the battery, it may be shunted to dump heaters. When the sun is not available, the battery supplies the load and the charge controller supplies the direct current to the dc loads. Figure 6 : Battery Storage Solar System

10 29 Optoelectronic Modeling of Solar Photovoltaic System for Rural Electrification Using Matlab 4. CONCLUSIONS A MATLAB based PV module model is present in this paper. The model includes the improved solar photovoltaic module and energy storage system. Using the present model an investigation is carried out at the site Banki and obtained the following results: Irrespective of non-uniform insolation the improved solar photovoltaic module produces more power as compared to the conventional photovoltaic system which is clearly shown in the figure 5 for all seasons in a year. To satisfy the load demand of people of Banki, 100 solar modules are incorporated in the system that produces an power of 17 kwhr. Despite of mechanical improvement of solar photovoltaic system, it can be further improved in terms of materials used in the manufacturing of photovoltaic modules. 5. REFERENCES 1. Kun Ding, XinGao Bian,HaiHao Liu, Matlab-Simulink Based Modeling to Study the Influence of Non-uniform Insolation Photovoltaic Array, IEEE TRANSACTION ON ENERGY CONSERVATIONS, VOL.23, March Rai, G. D., Non Conventional Energy Sources, Khanna Publishers, India, Malek, Norhazwani Abd, Hasini Hasril,, Rahman, Adlansyah Abd, Jaffar Mohd Nasharuddin Mohd Improved Solar PV System for Malaysian Rural Electrification, Proceedings of IEEE Student Conference on Research and Development, December 2010.

11 S.M. Ali, Bishnu Prasad Sahu And Sthitaprajna Rath P. Baltas, M. Tortoleli, and P. E. Russel, Photovoltaic designer ASUPVD, Arizona State University, Department of Electrical and Computer Engineering, Rauschenbach, H. S., Solar cell array design handbook, Litton Educational Publishing Inc., USA, M. Buresch: Photovoltaic Energy Systems Design and Installation, McGraw-Hill, New York, Matlab and Simulink, The Mathworks, Inc. as of September 2006,