Paper id 26201470

International Journal of Research in Advent Technology, Vol.2, No.6, June 2014 E-ISSN: 2321-9637

Design and Analysis of Photovoltaic Panel Array on the Basis of Radiation Variation Kavitha H. N1, Rajiv Dahiya2, Electronics and communication1, 2, PDM college of Engg1, 2 Email: kavithahn.ec@gmail.com1 , rajiv_engg@pdm.ac.in2

Abstract- The most common type of photovoltaic (PV) installation in residential applications is the centralized architecture. This realization aggregates a number of solar panels into a single power converter for power processing. The performance of Photovoltaic Panels measured on the basis of the efficiency of the system by variation in the radiation and constant temperature. Extensive simulation results are presented to verify these two performances. In this thesis we are analysis the performance of the PV array by using both the simulation results and simulink model. PV array gives higher efficiency. Analytical results are validated through detailed computer simulations using the Matlab/Simulink mathematical software package.

Index Terms- PV, Photovoltaic, Temperature, Radiation.

1. INTRODUCTION The world has paid attention to renewable energy due to fuel energy depletion and global warming. Among various renewable energies, PV system focused on high power generating system in the past. However, with development of semiconductor, it has been popularly used in low power applications such as buildings and home [1]-[3]. Basically, PV system needs PV panel to convert solar PV energy into electrical energy.

A PV array is made up of rectangular modules (or panels) that measure between 2 and 5 feet on a side.

The most common type of PV module has an aluminum frame and a glass cover protecting a collection polycrystalline PV cells. When exposed to light, each PV cell produces 0.5 volt DC — so if you add up the number of cells and divide by 2, you know the voltage of the module. The best performing commercially available PV cells are roughly 20% efficient at converting solar energy into electricity [7] .

Thin-film PV products have relatively low efficiencies usually in the range of 10% to 12% so they require almost twice the area required for a polycrystalline PV array with the same electrical output.

The operation of a photovoltaic (PV) cell requires 3 basic attributes: 1).The absorption of light, generating either electron-hole pairs, 2).The separation of charge carriers of opposite types. 3).The separate extraction of those carriers to an external circuit.

This electricity can then be used to power a load, such as a water pump, or it can be stored in a battery.

PV cells are based on a variety of light-absorbing materials, including crystalline and amorphous silicon, thin films such as cadmium telluride (CdTe) and copper indium gallium selenide (CIGS) materials, and organic/polymer-based materials.

A PV cell may be represented by the equivalent circuit model shown as fig. 1, consisting of a photon current source (IL), a diode, a series resistance (rs), and a shunt resistance (rsh).The series resistance (rs) represents the ohmic losses in the front surface of the cell and the shunt resistance (rsh) represents the loss due to diode leakage currents.

The conversion efficiency ( ) is defined as:

‌(1) and the fill factor (FF) given by

...(2) where Pin is the power input to the cell, Voc is the open circuit voltage, Isc is the short circuit current, and Im and Vm are the maximum cell current and voltage respectively at the maximum power point,

Fig. 1 Equivalent circuit of photovoltaic cell

Pm = ImVm. Critical PV cell performance parameters, such as the equivalent cell shunt and series resistance and the

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International Journal of Research in Advent Technology, Vol.2, No.6, June 2014 E-ISSN: 2321-9637 electrical conversion efficiency and fill factor, may be determined from I-V measurements. The cell must be maintained at a constant temperature and a radiant source with a constant intensity and a known spectral distribution must be used.

module with a number of cells connected in series and parallel the curves of individual cells simply add up along the voltage and current axes, respectively. To increase the output even more for a larger-scale electricity production system, several modules are connected in series and parallel to form a PV array.

2. PHOTOVOLTAIC SIMULINK MODEL PV cells have been made with silicon (Si), gallium arsenide (GaAs), copper indium diselenide (CIS), cadmium telluride (CdTe), and a few other materials.

The common denominator of PV cells is that a p–n junction, or the equivalent, such as a Schottky junction, is needed to enable the photovoltaic effect.

Understanding the p–n junction is thus at the heart of understanding how a PV cell converts sunlight into electricity.

Fig. 3 Simulink model

Fig. 2 Equivalent circuit for a solar cell

The actual current in a solar cell is the ideal current, i.e. the short-circuit current ISC, minus the current that flows through the diode, Id …(3) To get the relation of current and voltage in a PV cell we substitute the Shockley diode equation to the equation above. This yield

… (4) A photovoltaic array [4-5] (PV system) is an interconnection of modules which in turn is made up of many PV cells in series or parallel. As the voltage output of one PV cell is only about 0.5 V, several cells are coupled in series in order to increase the output. An assembly of a number of cells coupled and encapsulated in an appropriate package is called a solar or PV module that is the basic element for photovoltaic electricity production [9-10]. The voltage output of a module is a sum of the voltages of its cells connected in series. To increase the current, cells are connected in parallel, and similarly the current output of a module is a sum of the currents of the individual cells connected in parallel. In the I − V curve of a

Simulation performed using simulink model with the variation of temperature and radiation. Fig. 6.13 depicts the Simulink model for PV array. Fig. 6.14 shows the I-V curve at various temperature and constant irradiance. Fig. 6.15 demonstrates the P-V curve at various temperature and constant irradiance.

The power produced by a single module is seldom enough for commercial use, so modules are connected to form array to supply the load. The connection of the modules in an array is same as that of cells in a module. Modules can also be connected in series to get an increased voltage or in parallel to get an increased current.

Negative Factors affect the performance of Photovoltaic Cell [6] such as: The natural reflection of light off the surface of solar cells can greatly reduce efficiency. The reflection of light can be as high as 36% for untreated surfaces. The reflection of light off the surface due to the electric conductors further decreases the efficiency by reducing the amount of light shining through the solar cell. The reduction in light is equivalent to how much these contacts cover the surface, which is typically 8%.

Positive Factors affect the performance of Photovoltaic Cell [6-8] are: Making solar cells with shallow junctions that are less than 0.2 microns thick are called blue cells and can improve the efficiency of solar cells. Making the solar cell with a back surface field (BSF), which is a p+ layer on the bottom of the cell, can increase VOC and ISC resulting in a better FF and a higher efficient cell. The reflection of light off the surface of the solar cell can be reduced from as high as 36% to 5% if an antireflection coating, such as Silicon Oxide (SiO), and surface texturing are used.

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International Journal of Research in Advent Technology, Vol.2, No.6, June 2014 E-ISSN: 2321-9637 4. SIMULATION RESULTS Performance analysis based on the radiation variation and constant temperature There are three classic parameters that are very important on the PV characteristics namely shortcircuit current (Isc), open-circuit voltage (Voc) and the maximum power point (Pmp = Imp*Vmp).). Experiment is performed for radiation (s=120, 100, 80, 60, 40, 20) and temperatures as 28oC. Fig. 6.6 shows the I-V curve at 120W/m2 irradiance and constant temperature. Fig. 6.7 depicts the P-V curve at 120W/m2 irradiance and constant temperature. Fig. 6.8 demonstrates the P-I curve at 120W/m2 irradiance and constant temperature.Fig. 6.9 shows the I-V curve at various irradiance and constant temperature. Fig. 6.10 demonstrates the P-V curve at various irradiance and constant temperature. Fig. 6.11 shows the P-I curve at various irradiance and constant temperature.

Fig. 6.12 shows the Efficiency of PV array model with changing solar radiation. Simulation result reveals that as the solar radiation goes on increasing the efficiency of PV array goes on decreasing.

Fig. 5 P-I curve at 120W/m2 irradiance and constant temperature

Fig. 6 I-V curve at various irradiance and constant temperature Fig 4. I-V curve at 120W/m2 irradiance and constant temperature

Fig. 5 P-V curve at 120W/m2 irradiance and constant temperature

Fig. 7 P-V curve at various irradiance and constant temperature

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International Journal of Research in Advent Technology, Vol.2, No.6, June 2014 E-ISSN: 2321-9637 REFERENCES

Fig. 8 P-I curve at various irradiance and constant temperature

Fig. 9 Efficiency of PV array model with changing solar radiation

[1] J. P. Benner and L. Kazmerski, “Photovoltaics gaining greater visibility,”IEEE Spectr., vol. 36, no. 9, pp. 34–42, Sep. 1999.

[2] Z. Zhao, M. Xu, Q. Chen, J.-S. Lai, and Y. Cho, “Derivation of boostbuck converter based highefficiency robust PV inverter,” in Proc. IEEE Energy [3] R.W. Erickson and A. P. Rogers, “A microinverter for buildingintegrated photovoltaics,” in Proc. 24th Annu. IEEE Appl. Power Electron. Conf. Expos., Feb. 15–19, 2009, pp. 911–917.K. Elissa, “Title of paper if known,” unpublished.

[4] “Space Power and Radiation Effects,” class notes for EC3230, Department of Electrical and Computer Engineering, Naval Postgraduate School, Spring 2009.

[5] Frank kreith, D. Yogi Goswami, 2007, Handbook of Energy Efficiency and Renewable Energy, CRC Press, 2007.

[6] Markvart, T. and Castaner, L., (2003), "Practical Handbook of Photovoltaics, Fundamentals and Applications" Elsevier, 2003.

[7] Bishal Dhakal and Fernando Mancilla–David, “Centralized and Modular Architectures for Photovoltaic Panels with Improved Efficiency,” IEEE, 2012.

[8] A photovoltaic systems using advanced mppt method implemented in matlab. [Online]. Available: http://www.eetimes.com.

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[10] Z. M. Salameh and F. Dagher: The effect of electrical array reconfiguration on the performance of a PV powered volumetric water pump, IEEE Trans., EC-5, pp. 653 658, 1990.

5. CONCLUSION Note that the change in temperature will not likely to affect the function of MPPT because the power electronics operates much faster than the weather or temperature change. The actual temperature condition was not well known at the time of study. This paper is concerned with Photovoltaic Panels with Improved Efficiency.

In this thesis, we evaluate the performance of Photovoltaic Panels on the bases of the efficiency of the system by variation in the temperature and by variation in solar radiation.

Simulation result depicts that the efficiency of the system goes on decreasing with the increase in solar radiation it means that with low value of solar radiation PV array gives higher efficiency. Analysis of PV array on the basis of I-V, P-V and P-I characteristics by varying any one of the parameter either temperature or solar radiation and taking other parameter constant.

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