A

PROJECT REPORT

ON

STUDY, ANALYSIS AND SIMULATION OF PHOTOVOLTAIC SYSTEMS USING MATLAB

Submitted in partial Fulfllment for award of the degree of

BACHELOR OF TECHNNOLOGY

IN

ELECETRIC & ELECTRONIC ENGINEERING

By

Omar Abdelrahim, BT11/005 Under guidance of

Mr.Dileep Kumar(Assistant Professor)

DEPARTMENT OF ELECTRICAL ENGINEERING

NIMS INSTITUTE OF ENGINEERING AND TECHNOLOGY,

NIMS UNIVERSITY,

JAIPUR, RAJASTHAN

INDIA

May-2015

CERTIFICATE

I hereby certify that the work which is being presented in the B.Tech Minor Project Report entitled

“STUDY, ANALYSIS AND SIMULATION OF PHOTOVOLTAIC SYSTEMS USING MATLAB”, in partial fulfilment of the requirement for the award of the Bachelor of Technology in Electrical & Electronics Engineering and submitted to the Department of Electrical Engineering of NIMS Institute of Engineering & Technology, NIMS University, Jaipur, Rajasthan(India) is an authentic record of my own work carried out during a period of 8 th semester, under the supervision of Dileep Kumar, Assistant Professor and HOD, Department of Electrical Engineering.

The matter presented in this thesis has not been submitted by me for the award of any other degree elsewhere.

Signature of Candidate

1.OMAR ABDELRAHIM

BT11/005

This is to certify that the above statement made by the candidate is correct to the best of my knowledge.

Date: Signature of Supervisor(s)

ACKNOWLEDGEMENT

We express our deep sense of gratitude and immense respect to our revered guide Mr. Dileep Kumar, Head of the Department, Department of Electrical Engineering for suggesting the problems and his invaluable guidance, constant encouragement and successful completion of work. We have proud privilege to accomplish this entire work. The sincerity integrity and punctuality which he has incorporated in us will take us a long way in life.

It is an organization which inculcates a sense of responsibility towards society. We would therefore thank all the teachers of NIET especially Electrical Engineering Department, who are always ready to provide help and assistance regarding any matter.

ABSTRACT

All life on the earth depends on solar energy. Green plants make food by means of photosynthesis. Light is essential from in this process to take place. This light usually comes from sun. Animal get their food from plants or by eating other animals that feed on plants. Plants and animals also need some heat to stay alive. Thus plants are store houses of solar energy. The solar energy that falls on India in one minute is enough to supply the energy needs of our country for one day. Man has made very little use of this enormous amount of solar energy that reaches the earth. Energy from the sun is called solar energy. The Sun’s energy comes from nuclear fusion reaction that takes place deep in the sun. Hydrogen nucleus fuses into helium nucleus. The energy from these reactions flow out from the sun and escape into space. Solar energy is sometimes called radiant energy. These are different kinds of radiant energy emitted by sun. The most important are light infrared rays. Ultra violet rays, and X- Rays.

Basically photovoltaic effect can be observed in nature in a variety of materials, but the materials that are capable to achieve best performance in sunlight are the semi-conductors because when photon from the sun are absorbed in a semiconductor, they create free electron with higher energies than the electron which provide the bonding in the base crystal. Once these electrons created, there must be an electric field to induce these higher energy electrons to flow out of the semi-conductor to do useful work. The electric field in most solar cells is provided by a junction of materials which have different electrical properties.

This project is based on Construction and connection of photovoltaic module and related theories about it. To utilize maximum energy from the photovoltaic cell first of all understanding of it characteristics is very important because of this in starting of project we done proper study on characteristics of photovoltaic module and maximum power point. After got proper understanding of characteristics we try to use output of photovoltaic cell efficiently with help of Maximum power point tracker and cuk converter.

TABLE OF CONTENTS

TITLE PAGE……………………………………………………………………….i

CERTIFICATE…………………………………………………………………….ii

ACKNOWLEDGEMENT…………………………………..…………….….……iii

ABSTRACT ……………………………………………………………………….iv

TABLE OF CONTENTS…………………………………………………………....….v

LIST OF FIGURES……………………..……………..…………………………..vi

CHAPTERS…………………………………………………………………....…..vii

LIST OF FIGURE

Fig-1.1:- Solar Isolation in India............................................................03

Fig-1.2:- Figure of Photo Voltaic Cell...................................................05

Fig-1.3:- Energy Output Vs. Tilt Angle...................................................07

FIG-3.1:- Equivalent Circuit Photo Voltaic Cell....................................11

Fig-3-2:- I-V & P-V characteristics of Photovoltaic Cell and MPP...... 12

Fig-3.3-Series Connection of PV Cell....................................................13

Fig-3.4-Series Connection of 10 PV Cell...............................................13

Fig-3-5:-Series Connected PV Cells Output Voltage & Current...........14

Fig-3-6:-Parallel Connected PV Cells Output Voltage & Current.........15

Fig-3.7- PV Module................................................................................15

Fig-3.8- Bypass Diode............................................................................16

Fig-3.9:-Working Of Bypass Diode.......................................................16

Fig-3.10- Constructed PV Module Using MATLAB.............................17

Fig-3.11- PV Module connected with variable load and constant.........18

Fig-3.12:- I-V characteristics of Photovoltaic Module using MATLAB.................................................................................................19

Fig-3.13:- P-V characteristics of Photovoltaic Module using

MATLAB..............................................................................................19

Fig-3.14:- I-V & P-V characteristics of Photovoltaic Module by four level Irradiance and Maximum Power point saw by ‘*’ using MATLAB.................................................................................................20

Fig-4.1:- Basic Diagram of System........................................................21

Fig-4.2:- Arrangement of PMDC Operated by PV Module Using MATLAB...............................................................................................22

Fig.4.3:- Irradiance and solver configuration.........................................22

Fig.4.4:- Connection of solar cell........................................................23

Fig.4.5:- Output device scope in MATLAB.......................................24

Fig-4.6:- Flow chart of the perturb & observe.......................................23

Fig-4.7:- Circuit Diagram of Cuck Converter.......................................29

Fig-5.1 Irradiance vs. Time.................................................................30

Fig-5.2:-Output IV characteristics When Irradiance vary A/C to Ramp

Signal.......................................................................................................30

Fig-5.3:- Output IV characteristics When Irradiance vary A/C to Constant

Signal ........................................................................................31

Fig-5.3:- Output PV characteristics When Irradiance vary A/C to Constant

Signal ........................................................................................31

CHAPTERS

Chapter 1 Introduction

1.1Solar Energy.........................................................................01

1.1.1General Introduction of Solar Energy .....................................................01

1.1.2 Solar Energy applications.........................................................................01

1.1.3Basic ideas about the pre-historic way of using solar energy.................02

1.1.4Solar Isolation in India...............................................................................02

1.1.5 In Rajasthan...............................................................................................02

1.2 Electricity from Solar Energy.......................................................03

1.3 Introduction of Photo Voltaic Cell................................................04

1.3.1 To Obtain A Useful Power Output From Photon Interaction in A Semi-conductor three Process Are required....................................................04

1.3.2 Photo Voltaic Cell Consist Of ...................................................................04

1.3.3History of Photovoltaic Cell.......................................................................04

1.3.4 How PV Cells Are Made............................................................................05

1.3.5 Type PV Panels...........................................................................................06

1.3.6 Operational system of a PV panel.............................................................07

1.4 Project Contain...............................................................................08

1.4.1 Study of Construction PV Module ………………………….…………..08

1.4.2 Study of Characteristic of PV Module.....................................................08

1.4.3 Study of Construction PV Module............................................................08

Chapter 2 Literature Review

2.1 Basic Photovoltaic Principles and Methods.................................09

2.2 Connection of solar cells and mismatch between, Packaging of modules, Failure modes for modules S. Brenner..............................09

2.3 Renewable and Efficient Electric Power System, Gilbert M. Masters..................................................................................................10

2.4 Neeraj Tiwari.................................................................................10

Chapter 3 Study of Construction of PV Module and Its

Characteristics

3.1 Equivalent Circuit Photovoltaic Cell ...........................................11

3.1.1 I-V and P-V characteristics of Photovoltaic Cell and Maximum Power Point......................................................................................................................12

3.2Connecting solar cells......................................................................13

3.2.1 Solar Cells in Series...................................................................................13

3.2.2 Solar Cells in Parallel ................................................................................14

3.3 Connection for a Module...............................................................15

3.3.1 Bypass Diode..............................................................................................16

3.4 Construction of PV Module Using MATLAB..............................17

3.5 Study of PV Cell V-I & P-V Characteristics using MATLAB...18

3.5.1 PV Cell V-I & P-V Characteristics with constant irradiance and variable load........................................................................................................18

3.5.2 Design of Other Module which has four level Irradiance and Maximum Power point saw by ‘*’at its output...................................................................20

Chapter 4 Use Simulink To Modelling The PV Array

4.1 Basic Arrangement PV Module....................................................21

4.2 Modelling of PV Array using MATLAB....................................22

4.2.1 Irradiance....................................................................................................22

4.2.2 Photovoltaic Module..................................................................................23

4.2.3 XY Plot Scope ............................................................................................24

4.2.4 Maximum Power Point Tracker Controller............................................24

4.2.5 Cuk Converter ........................................................................................27

Chapter 5 RESULTS & DISCUSSION

5.1 Irradiance Vs Time.........................................................................30

5.2 Output When Irradiance vary A/C to Ramp signal…...............30

5.3 Output When Irradiance vary A/C to Constant Signal.............31

CONCLUSION.....................................................................................32

REFERENCES.....................................................................................34

Chapter 1

INTRODUCTION

1.1Solar Energy:-

1.1.1- General Introduction of Solar Energy:-

Energy from the sun is called solar energy. The Sun’s energy comes from nuclear fusion reaction that takes place deep in the sun. Hydrogen nucleus fuses into helium nucleus. The energy from these reactions flow out from the sun and escape into space.

Solar energy is sometimes called radiant energy. These are different kinds of radiant energy emitted by sun. The most important are light infrared rays. Ultra violet rays, and X- Rays.

The sun is a large sphere of very hot gases. Its diameter is 1.39x106KM. While that of the earth is 1.27x104 KM. The mean distance between the two is 1.5x108KM. The beam radiation received from the sun on the earth is reflected in to space, another 15% is absorbed by the earth atmosphere and the rest is absorbed by the earth’s surface. This absorbed radiation consists of light and infrared radiation without which the earth would be barren.

All life on the earth depends on solar energy. Green plants make food by means of photosynthesis. Light is essential from in this process to take place. This light usually comes from sun. Animal get their food from plants or by eating other animals that feed on plants. Plants and animals also need some heat to stay alive. Thus plants are store houses of solar energy. The solar energy that falls on India in one minute is enough to supply the energy needs of our country for one day. Man has made very little use of this enormous amount of solar energy that reaches the earth.

1.1.2 Solar Energy applications :-

1. Heating and cooling of residential building.2. Solar water heating.3. Solar drying of agricultural and animal products.4. Salt production by evaporation of seawater.5. Solar cookers.6. Solar engines for water pumping.7. Solar Refrigeration.8. Solar electric power generation.9. Solar photo voltaic cells, which can be used for electricity.10. Solar furnaces.

1.1.3Basic ideas about the pre-historic way of using solar energy:-

Energy is a common Man’s daily commodity: The world energy consumption in 1975 was 8002 million tons of coal equivalents and is expected to shoot up to 27,400 million tons of coal equivalents in the year 2000. It is becoming scarce day by day even then its demand is on the increase. The increased population has led to depletion of energy. The process of mankind has influenced the subsequent exploitation of new sources of energy from time to time. The utilization of coal, the development of hydro electricity, the discovery of oil and gas and the advents of nuclear energy are significantly mile stones in human history. Each new source brought about a preformed change in the life style of the people. Each new source supplemented the other.

The size of the balance of fossil fuels will be over within a hundred years. Hence it is essential to tap the other sources of energy to supplement the existing energy demands of all non-conventional energy sources, solar energy holds the greatest promise as it is abundant, renewable and pollution free. Its collection, storage on conversion is also easy. Hence worldwide attention is now focused on various methods of utilization of solar energy. All life on the earth depends on solar energy. Green plants make food by means of photosynthesis. Light is essential from in this process to take place. This light usually comes from sun. Animals get their food from plants are store houses of solar energy.

The solar energy that falls on India in one minute is enough to supply the energy needs of our country for one day. Man has made very little use of this enormous amount of solar energy. That reaches the earth he has used solar energy indirectly, for many thousands of years. Wind mills which are driven by wind that result from infrared solar energy.

1.1.4 Solar Isolation in India :-

1. India is having 5 trillion kWh/year theoretical potential. Most of the country receives more than 4 kWh/m2/day.

2. In most parts of India, clear sunny weather is experienced 250 to 300 a year.

1.1.5InRajsthan:-

1. Best solar radiation in India.

2. Solar radiation 6-7 kWh/sq. Meter.

3. More than 325 sunny days in a year (amongst the best in India).

Fig-1.1:-Solar Isolation in India

1.2 Electricity from Solar Energy:-

Electricity energy is the most convenient form of energy. It is easy to use, transport, control and transform into other forms of energy. Modern society has an in satisfied hunger for energy. This need for energy will continue to increase as the newly developing

countries become more industrialized and the mature nations increase their scope of Mechanization. To satisfy this need, vast quantities of coal and petroleum products are required. More recently, the advent of nuclear energy has added vast quantities for future need although sun is the ultimate source of all the power which man has at his disposal; the conversion of solar radiation directly into electrical power by some cheap and efficient means has been sought for several decades. Many different methods have been tried for this purpose, but none of these could complete with conventional fossil fuel or hydro electric power plants.

1.3Introduction of Photo Voltaic Cell :-

Basically photovoltaic effect can be observed in nature in a variety of materials, but the materials that are capable to achieve best performance in sunlight are the semi-conductors because when photon from the sun are absorbed in a semiconductor, they create free electron with higher energies than the electron which provide the bonding in the base crystal.

Once these electrons created, there must be an electric field to induce this higher energy electron to flow out of the semi-conductor to do useful work. The electric field in most solar cells is provided by a junction of materials which have different electrical properties.

1.3.1 To Obtain A Useful Power Output From Photon Interaction in A Semi-conductor three Process Are required:-

1. The photons have to be absorbed in the active part of the material and result in electron being exited to higher energy potential.

2. The electron-hole charge carried created by absorption must be physically separated and move to the edge of the cell.

3. The charge carries must be removed from the cell and delivered to a useful load before they lose their extra potential.

1.3.2 Photovoltaic Cell Consist Of:-

1. Electron hole pairs of semiconductor because they do absorption of incident solar radiation.

2. Front and back electrode to collect charge and3. Region containing a drift for charge separation.

1.3.3History of Photovoltaic Cell:-

The first conventional photovoltaic cells were produced in the late 1950s, and throughout the 1960s were principally used to provide electrical power for earth-orbiting satellites. In the 1970s, improvements in manufacturing, performance and quality of PV modules helped to reduce costs and opened up a number of opportunities for powering remote terrestrial applications, including battery charging for navigational aids, signals, telecommunications equipment and other critical, low power needs.

In the 1980s, photovoltaic became a popular power source for consumer electronic devices, including calculators, watches, radios, lanterns and other small battery-charging applications. Following the energy crises of the 1970s, significant efforts also began to develop PV power systems for residential and commercial uses, both for stand-alone, remote power as well as for utility-connected applications. During the same period, international applications for PV systems to power rural health clinics, refrigeration, water pumping, telecommunications, and off-grid households increased dramatically, and remain a major portion of the present world market for PV products. Today, the industry’s production of PV modules is growing at approximately 25 percent annually, and major programs in the U.S., Japan and Europe are rapidly accelerating the implementation of PV systems on buildings and interconnection to utility networks.

Fig-1.2:- Figure of Photo Voltaic Cell

1.3.4 How PV Cells Are Made :-

The process of fabricating conventional signal and polycrystalline silicon PV cells begins with very pure semiconductor-grade poly silicon - a material processed from quartz and used extensively throughout the electronics industry. The polysilicon is then heated to melting temperature, and trace amounts of boron are added to the melt to create a P-type semiconductor material. Next, an ingot, or block of silicon is formed, commonly using one of two methods: 1) by growing a pure crystalline silicon ingot from a seed crystal drawn from the molten polysilicon or 2) by casting the molten polysilicon in a block, creating a polycrystalline silicon material.

Individual wafers are then sliced from the ingots using wire saws and then subjected to a surface etching process. After the wafers are cleaned, they are placed in a phosphorus diffusion furnace, creating a thin N-type semiconductor layer around the entire outer surface of the cell. Next, an anti-reflective coating is applied to the top surface of the cell, and electrical contacts are imprinted on the top (negative) surface of the cell. An aluminized conductive material is deposited on the back (positive) surface of each cell, restoring the P-type properties of the back surface by displacing the diffused phosphorus layer. Each cell is then electrically tested, sorted based on current output, and electrically connected to other cells to form cell circuits for assembly in PV modules.

1.3.5 Type PV Panels :-

There are a variety of solar panels based on semiconductor materials and manufacturing methods. Additionally, they can be classified according to their final shape  .Types of panels depending on the material and manufacturing process. The types of solar panels that can be found on the market related to the materials and manufactured process used as below.

1. Mono crystalline Panels:These panels are sections of a silicon bar in one piece crystallized perfectly. The efficiency of these panels does not reach more than a 24.7% in laboratory and a 16% for commercial ones. The Figure 2 shows a mono crystalline panel, the most common PV system.

2. Polycrystalline Panels:Similar to the previous type but in this case the process of silicon crystallization is different. Polycrystalline panels are formed by pieces of a silicon bar that have been structured as disordered crystals. They are visually very recognizable because it presents a granulated surface. A lower efficiency than monocrystalline (19.8% laboratory and commercial modules 14%) is provided by these panel and consequently the price is also lower. This is the kind of panels selected for our case study.

3. Amorphous Panels:These panels have a considerable thickness. Using silicon with another structure or other semiconductor materials thinner and versatile panels can be obtained. In some cases these panels allow adaptation to irregular surfaces. They are called Amorphous PV Solar Panels or thin-film PV modules and they can be classified according to the material employed:Amorphous Silicon (TFS):Also manufactured with silicon, but differently from the previous examples. In this case the material does not have a crystal structure. Panels of this type are commonly used for small electronic devices (calculators, watches) and small portable panels. Its peak performance in the laboratory is roughly 13% and the commercial modules of 8%. Cadmium telluride, with a performance in laboratory of 16% and 8% in commercial modules. Gallium Arsenide is one of the most efficient materials with a 20% of efficiency on commercial panels.

4. Tandem Panels:There are also Tandem panels, which combine two different types of semiconductor materials. Each type of material absorbs only a part of the electromagnetic spectrum of solar radiation and

because of this a combination of two or three types of materials can be used to collect more than one of the electromagnetic spectrums. This type of panel can be as efficient as 35%.

1.3.6 Operational system of a PV panel :-

The operation of the solar panels is based on the photovoltaic effect which occurs when solar radiation incidences in semiconductor materials (with a determinate internal structure and characteristics) producing electricity. During the period of exposure to solar radiation, the photons (basic particles of light and electromagnetic radiation) give their energy to electrons in semiconductor materials, and then these electrons can break the potential barrier of the pn-junction and exit through the semiconductor creating an electrical current. The solar cells are combined in many different ways to achieve both desired voltage and power. The power of a Solar Panel is directly related to the peak power output, which represents the maximum power that a panel can generated in full sunlight. Another important point for understanding the PV panel’s installation is the Tilt or angle of inclination of the panels in the roof. The best angle is around 30° from the horizontal (as per this information source).Other factors as the temperature of the panels have not been taken into account due to the low temperatures reached in the UK. Nevertheless, the temperature of the panels is relevant in other region and must be considered; a reduction in the efficiency of the system can be produced is the temperature is too high. 

Figuer-1-3:- Energy Output Vs. Tilt Angle

1.4 Project Contain:-

1.4.1 Study of Construction PV Module:-

In this project first of all studied about different type construction of photovoltaic module, its result and working of by-pass diode. After this photovoltaic cell module constructed using MATLAB.

1.4.2 Study of Characteristic of PV Module:-

After study all general things about photovoltaic cell to use it efficiently knowledge of Characteristic of PV Module is very important so first constant irradiance applied on created PV module and check characteristics. After this irradiance of different level is applied and check characteristics and represent maximum power point on it. This all work done using MATLAB.

1.4.3 Modeling and simulation of Photovoltaic Array with PMDC Machine :-

After above all study modal created in which permanent Magnet Motor is operated as load by PV Module with help of cuk converter which is controlled by Maximum power point tracker.

Chapter 2

Literature Review

2.1 Basic Photovoltaic Principles and Methods:-

The research paper [1] presents a nonmathematical explanation of the theory and design of PV solar cells and systems. It is written to address several audiences: engineers and scientists who desire an introduction to the field of photovoltaic, students interested in PV science and technology, and end users who require a greater understanding of theory to supplement their applications.

The book is effectively sectioned into two main blocks: Chapters 2-5 cover the basic elements of photovoltaic-the individual electricity-producing cell. The reader is told why PV cells work, and how they are made. There is also a chapter on advanced types of silicon cells. Chapters 6-8 cover the designs of systems constructed from individual cells-including possible constructions for putting cells together and the equipment needed for a practical producer of electrical energy. In addition, Chapter 9 deals withPV's future. Chapter 1 is a general introduction to the field. The authors of this document are Paul Hersch and Kenneth Zweibel. They would like to thank their colleagues at the Solar Energy Research Institute's Solar Electric Conversion Division who reviewed the manuscript for technical accuracy: Richard Bird, Kathryn Chewey, Satyen Deb, Keith Emery, Kay Firor, Steve Hogan, Larry Kazmerski, Jack Stone, Thomas Surek, and Simon Tsuo. Gary Cook and Richard Piekarski of the Technical Information Office, who designed the document, were also helpful readers. GraphicDirections of Boulder, Colorado, were responsible for the text's figures, often with valuable improvements. Ray David was the cover artist. Vincent Rice of the Photovoltaic Program Office at DOE was supportive throughout, giving impetus to the project. All introduction portion of the project report is made with help of above book.

2.2 Connection of solar cells and mismatch between, Packaging of modules, Failure modes for modules:-

The research paper [6] presents the behaviour and design ofsolar cells in isolation. In practice they are connected together and packaged as a module to provide specific power output and to protect the solar cells from the elements. We will look in more detail at the following issues Connection of solar cells and mismatch between, Packaging of modules, Failure modes for modules.

All study about Construction of module, array, connection of solar cell with them output, mismatch cases, blocking diode in this project report is based on this research paper.

2.3 Renewable and Efficient Electric Power System, Gilbert M. Masters :-

The research [15] contains information about all renewable sources electrical power system and made efficient electrical power system. All study about photovoltaic cell equivalent circuit; Test I-V and P-V characteristics for a photovoltaic module; determine the optimal conditions for operating a PV panel in a circuit with a known load and understand MPP (maximum power point); Investigate the effects of solar isolation, shading, and tilting angle of a solar panel on an I-V characteristic are basis of this book.

The research paper[2] mostly contain cuk converter, MPPT, PV system, simulation so all study about maximum power point tracker and cuk converter in this project is made with help of this research paper. To increase its efficiency MPPT techniques are used. The main disadvantage of solar system is its variable voltage. And to obtain a stable voltage from solar panels DC-DC converters are used. DC-DC converters are of mainly three types buck, boost and cuk. This paper presents use of cuk converter with MPPT technique. Generally buck and boost converters used. But by using cuk converter we can step up or step down the voltage level according to the load requirement. The circuit has been simulated by MATLAB and Simulink software.

Chapter 3

Study of Construction of PV Module and Its Characteristics

3.1 Equivalent Circuit Photovoltaic Cell :-

To Study Photovoltaic cell characteristics first of all understand equivalent Circuit Photo Voltaic Cell and its characteristics with meaning of Maximum power point. Incident sunlight can be converted into electricity by photovoltaic conversion using a solar panel. A solar panel consists of individual cells that are large-area semiconductor diodes, constructed so that light can penetrate into the region of the p-n junction. The junction formed between the n-type silicon wafer and the p-type surface layer governs the diode characteristics as well as the photovoltaic effect. Light is absorbed in the silicon, generating both excess holes and electrons. These excess charges can flow through an external circuit to produce power.

FIG-3.1:- Equivalent Circuit Photo Voltaic Cell

WhereIsc is short circuit current, I0 is the reverse saturation current of the diode, and A is temperature-dependent constant, A=q/kT [1]. If the solar cell is open circuited, then all of the Iscflows through the diode and produces an open circuit voltage Voc of about 0.5-0.6V. If the solar cell is short circuited, then no current flows through the diode, and all of the short-circuit current Isc flows through the short circuit.

Since the Voc for one solar cell is approximately 0.5-0.6V, then individual cells are connected in series as a “solar panel” to produce more usable voltage and power output levels. Most solar panels are made to charge 12V batteries and consist of 36 individual cells (or units) in series to yield panel Voc≈18-20V. The voltage for maximum panel power output is usually about 16-

17V. Each 0.5-0.6V series unit can contain a number of individual cells in parallel, thereby increasing the total panel surface area and power generating capability.

3.1.1 I-V and P-V characteristics of Photovoltaic Cell and Maximum Power Point:-

Figuer-3-2:- I-V & P-V characteristics of Photovoltaic Cell and MPP

Above figure illustrates the I-V curve and power output of a solar panel. If no load is connected with solar panel which is sitting in the sun, an open circuit voltage Voc will be produced but no current follows. If the terminals of the solar panel are shorted together, the short-circuit current Isc will flow but the output voltage will be zero. In both cases, no power is delivered by the solar panel. When a load is connected, we need to consider the I-V curve of the panel and the I-V curve of the load to figure out how much power can be delivered to the load. The maximum power point (MPP) is the spot near the knee of the I-V curve, and the voltage and current at the MPP are designated as Vm and Im. For a particular load, the maximum point is changing as the I-V curve is varying with the temperature, isolation, and shading. Because solar power is relatively expensive, it is important to operate panels at their maximum power conditions. In fact DC-DC converters are often used to “match” the load resistance to the venin equivalent

resistance of the panel to maximize the power drawn from the panel. These “smart” converters are often referred to as “tracking converters”.

3.2 Connecting solar cells :-We need to understand how the different connections between solar cells affect performance and most critically what happens when solar cell performance is mismatched. We will look at whether the solar cells are connected in:

1. Series: give greater voltage2. Parallel: gives greater current

3.2.1 Solar Cells in Series :-

Simplest thing to consider is when we have two identical solar cells connected in series.

Fig-3.3-Series Connection of PV CellSince the cells are in series, the currents will be matched (not a problem as they are identical), voltages will add. Useful for when we want a specific voltage, typical voltages for a single solar cell will be < 0.6 V.

Fig-3.4-Series Connection of10 PV Cell

Since the voltages add when in series, if the mismatch is in voltage there is no problem. When the mismatch is in current then we have a much bigger problem since in series we want current constant through allot the solar cells. So in series connected solar cells the current for the chain inset by the current of the worst performing cell, this is bad but it gets worse when we have a short circuit condition. We can get a situation where the worst performing solar cell is reverse biased and is dissipating power. Major cause of cracking and all-around destruction of solar cells in modules. Need to consider the current match condition and the IV-Characteristics for the solar cells. Current mismatch is worse than voltage mismatch. Can get a serious mismatch for nominally identical cells when one or more is shaded.

Figuer-3-5:-Series Connected PV Cells Output Voltage & Current

Voltages add together at each value of current. At higher currents output is pinned by the Isc of the bad cell therefore power reduction is severe. Power is being dissipated in bad cell Situation is most severe if we have a short circuit over the chain of cells.

3.2.2 Solar Cells in Parallel :-

Currents add, voltage is the same across cells in parallel. Obviously can use parallel connection to boost current output. Currents add, so no real problem, as long as open circuit voltages are same.

Power is reduced slightly compared to independently biased cells but effect is minimal. Mismatch in voltage is more drastic

Figuer-3-6:-Parallel Connected PV Cells Output Voltage & Current

.

3.3 Connection for a Module :-

Most often for a module we have 36 solar cells connected in series. Reason is, we will typically get 17-18 V output voltage which makes it compatible with 12 V applications.

Fig-3.7- PV Module

3.3.1 Bypass Diode :-

Put ‘bypass’ diode in parallel to cell with opposite polarity. This prevent PV module when one of cell in it suffer shadow or damage.

Fig-3.8- Bypass Diode

Diodes switch on when voltage across bad cell reaches turn on voltage. To understand its operation look at I-V curve for a solar cell with a bypass diode.

Figer-3-9:-Working Of Bypass Diode

The presence of the bypass diode limits the voltage across the cell in reverse bias to pass a certain current and hence less power is dissipated.

3.4 Construction Of PV Module Using MATLAB :-

Fig-3.10- Constructed PV Module Using MATLAB

There is 6 photo cell connected in series in one array. This type of three arrays connected in series and made Array which consist 18 cells. This type of two arrays which are connected in parallel is made array of 36 cells, this so on as till array made which consist 72 cells in Series.

In above figure represent a constant irradiance (300) applied in above discuss module than 39.7 output voltage got from it.

3.5 Study Of PV Cell V-I & P-V Characteristics using MATLAB :-

3.5.1 PV Cell V-I & P-V Characteristics with constant irradiance and variable load :-

Fig-3.11- PV Module connected with variable load and constant irradiance

In above circuit, Irradiance provided to PV Module and PV Module operated by varying resistance. Irradiance value is taking 1000 in default condition. But when we Increase the Irradiance than maximum power point goes high and when we decrease irradiance than can get more power output from PV Module. Maximum power point goes low. Two scopes are connected with this module one represent I-V characteristics & other represent P-V characteristics.

Fig-3.12:- I-V characteristics of Photovoltaic Module using MATLAB

Fig-3.13:- P-V characteristics of Photovoltaic Module using MATLAB

3.5.2 Design of Other Module which has four level Irradiance and Maximum Power point saw by ‘*’at its output:-

Fig-3.14:- I-V & P-V characteristics of Photovoltaic Module by four level Irradiance and Maximum Power point saw by ‘*’ using MATLAB.

Above is achieving by programming in script file for created module and load. This programming is representing in Appendix-A.

Chapter 4

Use Simulink to Modelling the PV Array

4.1 Basic Arrangement of PV Module:-

Fig-4.1- Basic Diagram of System

Above figure represent block diagram of typical solar cell connected instead of light bulb. Typically a solar cell can be modelled by a current source and an inverted diode connected in parallel to it. It has its own series and parallel resistance. Series resistance is due to hindrance in the path of flow of electrons from n to p junction and parallel resistance is due to the leakage current.

When irradiance hits the surface of solar PV cell, an electrical field is generated inside the cell. As seen in Fig.4.1 this process separates positive and negative charge carriers in an absorbing material (joining p-type and n-type). In the presence of an electric field, these charges can produce a current that can be used in an external circuit. This generated current depends on the intensity of the incident radiation. The higher the level of light intensity, the more electrons can be unleashed from the surface, the more current is generated.

4.2 Modelling of PV Array using MATLAB :-

Below diagram represent modelling of pv array in Matlab&Simulink.In this model there are various type of simulink components are used. When the constant irradiance comes on the pv module then it generate the electricity which is passes through the variable load. The load resistance is varied according to the ramp signal. The voltage is measure on the load on scope. The characteristics of voltage-current and power-voltage are shown on scope.

Fig-4.2- Modelling PV Array Using MATLAB

4.2.1 Irradiance :-

Fig.4.3 irradiance and solver configuration

In real world irradiance is not constant. It is vary according to time. For design system which can applicable in real world, provide variable irradiance is necessary. The irradiance in this project is constant irradiance.

Solver Configuration :The Solver Configuration block specifies the solver parameters that your model needs before you can begin simulation.

Each topologically distinct Simscape block diagram requires exactly one Solver Configuration block to be connected to it.

Simulink Ps Converter :The Simulink-PS Converter block converts the input Simulink® signal into a physical signal.

Use this block to connect Simulink sources or other Simulink blocks to the inputs of a Physical Network diagram.

4.2.2 Photovoltaic Module:-

As discuss in above chapter 3 there is 6 photo cells connected in series in one array. This type of three arrays connected in series and made Array which consist 18 cells. This type of two arrays which are connected in parallel is made array of 36 cells, this so on as till array made which consist 72 cells in Series.

Fig.4.4connection of solar cell

4.2.3XY Plot Scope:-

Fig.4.5 output device scope in Matlab

It is the output device which is use to get the PV and IV characteristics of PV array in Matlab. Plots second input (Y) against first input (X) at each time step to create an X-Y plot. Ignores data outside the ranges specified by x-min, x-max, y-min, y-max.

4.2.4 Maximum Power Point Tracker Controller:-

To make best use of the solar PV system, output is maximized by electrically tracking the operating point by manipulating the load to maximize the power output under changing condition of isolation and temperature. This is achieving with help of maximum power point tracker controller.

Several techniques for tracking MPP have been proposed, as described in Section I. Two algorithms are commonly used to track the MPPT - the P&O method and Inc Cond method. The P&O method has been broadly used because it is easy to implement. Figure 3 presents the control flow chart of the P&O algorithm. The MPP tracker operates by periodically incrementing or decrementing the solar array voltage. If a given perturbation leads to an increase (decrease) the output power of the PV, then the subsequent perturbation is generated in the same (opposite)direction. In Figure 3, set Duty out denotes the perturb bation of the solar array voltage, and Duty+ and Duty- represent the subsequent perturbation in the same or opposite direction, respectively.

Fig-4.6:- Flow chart of the perturb & observe

In this system MPPT is work by programming as provided to it. Programming as per change in duty cycle controlled method. Programming of MPPT represent in Appendix-B. MPPT output fed to PWM and this output fed to cuk converter. Duty cycle is multiply by 100 and saw percentage change in duty cycle in indicator.

Restrictions of Perturb & Observe algorithm

In a situation where the irradiation changes quickly, the Maximum Power Point also moves on the right hand side of the curve. The algorithm takes it as a change due to perturbation and in the next iteration it changes the direction of perturbation and hence goes away from the MPP as shown in the figure. However, in this algorithm we use only a single sensor, the voltage sensor, to sense the solar array voltage and so the cost of implementation is less and hence easy to carry out. The time complexness of this algorithm is very less but on reaching very close to the MPP it doesn’t stop at the MPP and keeps on perturbing in both the directions. When this happens the algorithm has reached very close to the MPP and we can set an appropriate error.

INCREMENTAL CONDUCTANCE METHOD:

Incremental conductance method uses two voltage and current sensors to sense the output voltage and current of the PV array. At MPP the slope of the PV curve is 0.

(dP/dV)MPP=d(VI)/Dv

0=I+VdI/dVMPP

dI/dVMPP = - I/V

The left hand side is the instantaneous conductance of the solar panel. When this instantaneous conductance equals the conductance of the solar then MPP is reached.

Here we are sensing both the voltage and current simultaneously. Hence the error due to change in irradiance is eradicated. Nevertheless, the complexity and the cost of implementation increases. As we go down the list of algorithms the complexity and the cost of implementation goes on increasing which may be suitable for a highly elaborated system. That is why the reason that Perturb and Observe and Incremental Conductance method are the most widely use algorithms. Owing to its simplicity of implementation we have chosen the Perturb & Observe algorithm for our study among the two.

4.2.5 Cuk Converter:-

Many years ago, Dracut invented the integrated magnetic concept called Dc-transformer, where the sum of Dc fluxes created by currents in the winding of the input inductor L1and transformer T is equal to Dc flux created by the current in the output inductor L2 winding. Hence the Dc fluxes are opposing each other and thus result in a mutual cancellation of the Dc fluxes. The main applications of this circuit are in regulated dc power supplies, where a negative polarity output may be desired with respect to the common terminals of the input voltage and the average output is either higher or lower than the dc input voltage. The typical schematic circuit for the Cuk Converter is as shown in Fig. 1. The capacitor C1acts as a primary means to store and transfer the power from input to output. The voltagevc1 is always greater than either input or output voltage. The average output to input relations are similar to that of a buck-boost converter circuit.The output voltage is controlled by controlling the switch-duty cycle. The ratio of output voltage to input voltage is given by:

Where, Vo and Vin are the output and input voltages, respectively. The term Io and Iinis the output and input currents, respectively. The term D is the duty ratio and denoted as the ratio of the on time of the switch to the total switching period. This shows the output voltage to be higher or lower than the input voltage, based on theduty-ratio D.

The Cuk converter is a step-down/step-up converter based on a switching boost-buck topology. Essentially, the converter is composed of two sections, an input stage and an output stage. The input voltage vg is fed into the circuit via inductor L1. When transistor Q1 is on, current i1builds the magnetic field of the inductor in the input stage. The diode CR1 is reverse biased, and energy dissipates from the storage elements in the output stage. When Q1 turns off, inductor L1 tries to maintain the current flowing through it by reversing polarity and sourcing current as its magnetic field collapses. It thus provides energy to the output stage of the circuit via capacitor C1. R1 and R2 are parasitic or stray resistances of inductor.

The voltage ratio of a Cuk converter is the same as that of a buck-boost converter, but its main advantage over other converters is that the input and output inductors result in a filtered current on both sides of the converter, while buck, boost, and buck-boost converters have a pulsating current that occurs on at least one side of the circuit i.e. either on input side or output side. This pulsation will increase the ripple in the circuit and due to this ripple; the efficiency of battery gets lowered. To ensure good efficiency ripple should be reduced. By controlling the duty cycle of the switch, the output voltage Vo can be controlled and can be higher or lower than the input voltage vg. By using a controller to vary the duty cycle during operation, the circuit can also be made to reject disturbances ,as second part of circuit consists of parallel resonance

circuit and it work as a tank circuit for specific frequency (resonant frequency) , and during resonance current will not be allowed to enter in the circuit.

Fig-4.7:- Circuit Diagram Of Cuk Converter

Using voltage-balance condition across L1, maximum voltage U1 across C1 can be rewritten as:

This equation shows that this operating mode causes high voltage stress across the devices. Capacitor C1.=

Inductor L1:-The value corresponding to the linear ramp during the switch on-time. This occurs due to the oscillation with capacitor C1 in the off interval.

Inductor L2:-

Capacitor C2:-

Chapter 5

RESULT & DISCUSSION

5.1 Irradiance Vs Time:-

Fihuer-5.1:- Irradiance Vs Time Graph

In real world we have to get work under 10 to 12 hour of solar isolation but here we count 12 second as a 12 hour and provide 12 second isolation as 12 hour. But for study it takes too much time so for simplicity 3 sec time is consider. For 0 to 1 second graph is increase than 1 to 2 second it’s got steady and after 2 to 3 it decreases. Above graph is input signal graph.

5.2 :-Output when Irradiance vary A/C to Ramp signal:-

Figure-5.2:- IV characteristic

5.3 :-Output when Irradiance vary A/C to Constant signal:-

Figuer-5.3:- IV characteristics

Figuer-5.4:- PV characteristics

Chapter 6

CONCLUSION

In summary, this study presents a general purposes PV simulation module and its application examples in Matlab/Simulink simulation environment. This PV model is easy to configure for a desired PV response characteristics and it directly connects to Sim Power Systems electrical circuit for transient response analyses. The PV module has two main parts: A behavioural model of PV cells and a power–limited electrical driver for circuit connection. The behavioural model estimates voltage and current potential of PV panel for a given solar radiation (G) and module temperature (Tc) conditions. The power–limited electrical driver implements a relevant electrical response on the load. The proposed PV module can be employed in transient analysis of power system supplied with PV panels. It is also useful for testing MPP tracking methods. Nowadays, solar energy integration in micro grids is becoming primary concern of power system industry. Modelling renewable energy sources for a large-scale power system integration simulation is more important today, because these simulation tools will be a part of optimal design and intelligent management process. And thus conclusion is drawn

[1] In this project 72 cells are used in series which are connected to constant irradiance. It gives the maximum output up to 147 watt.

[2] Maximum output is generate by the photo voltaic array when load is variable. in this project load is vary according to the ramp signal .the power is generated by PV array is in between 85 to 147 watt.

[3] When irradiance of photo voltaic array is vary according to the ramp signal then the output graph in between IV and PV are shown in above graph.

[4] When irradiance is vary according to the ramp signal then the output is zero at initial condition. When irradiance is at maximum level then output is also maximum.

6.2 FUTURE SCOPE:-

This photovoltaic based system project demonstration to utilize solar power for does desire work. With increase demand of energy, energy shortage is big problem this can be minimizing by increase usage of non conventional energy sources. In most parts of India, clear sunny weather is experienced 250 to 300 a year. India is having 5 trillion kWh/year theoretical potential. Most of the country receives more than 4 kWh/m2/day and photovoltaic array is best way to generate electricity from solar. So by maximize usage of photovoltaic array India can satisfy it power demand. Due to this future scope of photovoltaic based system is very bright in India but this project can be most suitable and would be use below to application in future.

[1] After increase size of photovoltaic array and photovoltaic output power this project would be use in farm or well to drawn pump. To use this project in this application is require arrangement which prevent connection of motor to photovoltaic array when irradiance is below one level.

[2] This project may more efficient if it integrated with wind mill so solar-wind integrated system found which is more efficient.

[3] In most of wind mill induction motor is used which first drawn by power supply and when it rotate more than its synchronous speed than its work as induction generator and give power. This starting time need of power is satisfy by government power grid in present time. But in future this starting time need of power would be satisfy by photovoltaic systems which make operation of wind mill very efficient. To use this project in this application may require arrangement to convert cuk converter output voltage in ac and fed it to induction motor of wind mill.

REFERENCES

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[4] DivyaTeja Reddy Challa1, I. Raghavendar2,” Implementation of Incremental Conductance MPPT with Direct Control Method Using Cuk Converter” International Journal of Modern Engineering Research (IJMER) Vol.2, Issue.6, Nov-Dec. 2012 pp-4491-4496 ISSN: 2249-6645

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