mppt report

66
i COMPARISON STUDY OF MAXIMUM POWER POINT TRACKER TECHNIQUES FOR PV SYSTEM APPLIED TO UNIVERSAL MOTOR A PROJECT REPORT Submitted by DHARMIGARI SHRI SURYA (312211105027) DUVVURI VENKATA PAVAN KUMAR (312211105030) KURAPATI VINUTHNA (312211105053) in partial fulfillment for the award of the degree of BACHELOR OF ENGINEERING in ELECTRICAL AND ELECTRONICS ENGINEERING SRI SIVASUBRAMANIYA NADAR COLLEGE OF ENGINEERING, KALAVAKKAM ANNA UNIVERSITY: CHENNAI 600025 APRIL 2015

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Maximmum Power Point tracking

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  • i

    COMPARISON STUDY OF MAXIMUM POWER

    POINT TRACKER TECHNIQUES FOR PV SYSTEM

    APPLIED TO UNIVERSAL MOTOR

    A PROJECT REPORT

    Submitted by

    DHARMIGARI SHRI SURYA (312211105027)

    DUVVURI VENKATA PAVAN KUMAR (312211105030)

    KURAPATI VINUTHNA (312211105053)

    in partial fulfillment for the award of the degree

    of

    BACHELOR OF ENGINEERING

    in

    ELECTRICAL AND ELECTRONICS ENGINEERING

    SRI SIVASUBRAMANIYA NADAR COLLEGE OF ENGINEERING,

    KALAVAKKAM

    ANNA UNIVERSITY: CHENNAI 600025

    APRIL 2015

  • ii

    ANNA UNIVERSITY:CHENNAI 600025

    BONAFIDE CERTIFICATE

    Certified that this project report COMPARISON STUDY OF MAXIMUM

    POWER POINT TRACKER TECHNIQUES FOR PV SYSTEM

    APPLIED TO UNIVERSAL MOTOR is the bonafide work of

    DHARMIGARI SHRI SURYA(312211105027),

    DUVVURI VENKATA PAVAN KUMAR (312211105030),

    KURAPATI VINUTHNA(312211105053), who carried out the project work

    under my supervision.

    DR. V.KAMARAJ Mr. M. PANDI KUMAR

    HEAD OF THE DEPARTMENT GUIDE

    Professor Assistant Professor

    Department of Electrical Department of Electrical

    andElectronics Engineering andElectronics Engineering

    SSN College of Engineering, SSN College of Engineering,

    Kalavakkam, Kalavakkam,

    Chennai 603110 Chennai - 603110

  • iii

    VIVA VOICE EXAMINATION

    The Viva examination for the project work, Comparison study of Maximum

    Power Point Tracker techniques for PV system applied to universal motor

    submitted by

    DHARMIGARI SHRI SURYA(312211105027),

    DUVVURI VENKATA PAVAN KUMAR (312211105030),

    KURAPATI VINUTHNA(312211105053)

    held on ___________________

    Internal Examiner External Examiner

  • iv

    ACKNOWLEDGEMENT

    I would like to express my gratitude to the below mentioned people who

    have been instrumental in the completion of this project.

    I express my deep respect to PADMA BHUSHAN Dr. SHIV NADAR,

    Chairman, SSN Institutions for working on a great mission and vision and

    providing excellent infrastructure.

    I thank our President Ms. KALA VIJAYAKUMAR for providing the

    required facilities and infrastructure which helped me to complete the project.

    The Principal, Dr. S. SALIVAHANAN provided a great support to work. I

    express my gratitude to him.

    I would like to dedicate my sincere thanks to my guide Dr.

    V.KAMARAJ Professor and Head, Department of Electrical and Electronics

    Engineering, who has been kind, patient and provided great support. I express

    my deep felt gratitude to him.

    I would also like to thank our project coordinator Mr.M.PANDI

    KUMAR, Assistant Professor, Department of Electrical and Electronics

    Engineering, who showed their benevolence and helped us through tough

    periods.

    I extend my sincere thanks to the staff members and lab technicians,

    Department of Electrical and Electronics Engineering for providing great

    support at different times. I am grateful to them.

  • v

    ABSTRACT

    The need for renewable energy sources is on the rise because of the acute energy

    crisis in the world today. India plans to produce 20 Gigawatts Solar power by

    the year 2020, whereas we have only realized less than half a Gigawatt of our

    potential as of March 2010. Solar energy is a vital untapped resource in a

    tropical country like ours. Photovoltaic(PV) offers an environmentally friendly

    source of electricity, which is however still relatively costly today. The main

    hindrance for the penetration and reach of solar PV systems is their low

    efficiency and high capital cost. The maximum power point tracking (MPPT) of

    the PV output for all sunshine conditions is a key to keep the output power per

    unit cost low for successful PV applications. In order for photovoltaic (PV)

    systems to maximize their efficiency of power generation, it is crucial to locate

    the maximum power point (MPP) in real time under realistic illumination

    conditions. The current-voltage (I-V) characteristics of PV devices are

    nonlinear, and the MPP may vary with intrinsic and environmental conditions.

    Maximum power point tracking (MPPT) control is expected to seek the MPP

    regardless of the device and ambient changes.These techniques vary in many

    aspects as simplicity, digital or analogical implementation, sensor required,

    convergence speed, range of effectiveness, implementation hardware,

    popularity, cost and in other aspects. Our project aims on a comparitive study

    between four most popular MPPT techniques which are Incremental

    conductance algorithm, Perturb and Observe algorithm , Current sweep method,

  • vi

    Short Circuit Current method and Open Circuit Voltage Method. Universal

    motor will be used as load to the PV system. The prototyping PV system is

    implemented with a boost DC-DC converter using Microcontroller and

    MATLAB Simulink tools to execute the MPPT algorithms. Few comparisons

    such as voltage, current and power output for each different combination have

    been recorded. The above mentioned algorithms are implemented and tested

    under different conditions and the test results are analyzed and compared. This

    comparison helps in determining the optimal efficient technique and

    significantly improves the tracking accuracy and speed of the MPPT control.

  • vii

    TABLE OF CONTENTS

    CHAPTER NO. TITLE PAGE NO.

    ABSTRACT iv

    LIST OF TABLES ix

    LIST OF FIGURES ix

    1. INTRODUCTION 1

    1.1 NEED FOR RENEWABLE ENERGY

    1.2 DIFFERENT SOURCES OF RENEWABLE

    ENERGY

    1.2.1 WIND POWER

    1.2.2 SMALL HYDRO POWER

    1.2.3 BIOMASS

    1.2.4 GEOTHERMAL

    1.2.5 SOLAR POWER

    1.3 LITERATURE REVIEW

    1.4 OBJECTIVE

    1.5 FUTURE SCOPE OF RENEWABLE

    ENERGY RESOURCES

    1.6 THESIS OUTLINE

    2. MODELLING OF PV PANEL 10

    2.1 PHOTOVOLTAIC CELL

    2.2 PV CELL

    2.3 PV ARRAY

    2.4 PV MODELLING

    2.4.1 NOMENCLATURE

    2.4.2 INTRODUCTION

    2.4.3 MATHEMATICAL MODEL OF

    PHOTOVOLTAIC CELL

  • viii

    2.4.4 REFERENCE MODEL

    2.4.5 STEP BY STEP PROCEDURE FOR

    SIMULINK MODELLING OF PV

    MODULE

    2.4.6 CONCLUSIONS

    3. BOOST CONVERTER 28

    3.1 MODE1 OPERATION OF BOOST

    CONVERTER

    3.2 MODE2 OPERATION OF BOOST

    CONVERTER

    3.3 MODELLING OF BOOST CONVERTER

    USING MATLAB

    3.4 DESIGN APPROACH OF PROPOSED

    BOOST CONVERTER

    4. MAXIMUM POWERPOINT TRACKING 33

    4.1 AN OVERVIEW OF MAXIMUM POWER

    POINT TRACKING

    4.2 DIFFERENT MPPT TECHNIQUES

    4.3 PERTURB AND OBSERVE

    4.4 INCREMENTAL CONDUCTANCE

    4.5 FRACTIONAL OPEN CIRCUIT VOLTAGE

    4.6 FRACTIONAL SHORT CIRCUIT CURRENT

    4.7 DETAILS OF PERTURB AND OBSERVE

    ALGORITHM

    4.7.1 MODELLING OF P&O ALGORITHM

    4.7.2 COMPLETE MODEL OF PV PANEL

    WITH MPPT

    4.7.3 OUTPUT CHARACTERISTICS

    4.8 DETAILS OF INCREMENTAL CONDUCTANCE

    ALGORITHM

    4.8.1 MODELLING OF INCREMENTAL

    CONDUCTANCE ALGORITHM

    4.8.2 COMPLETE MODEL OF PV PANEL

    WITH MPPT

  • ix

    4.8.3 OUTPUT CHARACTERISTICS

    4.9 DETAILS OF SHORT CIRCUIT CURRENT

    ALGORITHM

    4.9.1 COMPLETE MODEL OF PV PANEL

    WITH MPPT

    4.9.2 OUTPUT CHARACTERISTICS

    4.10 DETAILS OF OPEN CIRCUIT VOLTAGE

    ALGORITHM

    4.10.1 COMPLETE MODEL OF PV PANEL

    WITH MPPT

    4.10.2 OUTPUT CHARACTERISTICS

    4.11 COMPARISON OF MPPT

    5. HARDWARE IMPLEMENTATION 45

    5.1 HARDWARE COMPONENTS

    5.2 HARDWARE SETUP

    5.3 SUB CIRCUITS

    5.3.1 SUPPLY CIRCUIT

    5.3.2 CONTROL CIRCUIT

    5.3.3 OPTOCOUPLER CIRCUIT

    5.3.4 POWER CIRCUIT

    5.4 MATLAB INTERFACE WITH ARDUINO

    FOR SERIAL COMMUNICATION

    5.5 TESTING AND RESULT

    6 CONCLUSION AND FUTURE WORK 51

    7 REFERENCES 52

    LIST OF TABLES

    TABLE NO. TABLE NAME PAGENO.

    2.1 ELECTRICAL CHARACTERISTICS 12

    DATA OF SOLAR 36W PV MODULE

  • x

    3.1 SPECIFICATIONS FOR BOOST 21

    CONVERTER

    4.1 COMPARISON OF MPPT ALGORITHM 43

    5.1 HARDWARE COMPONENTS 45

    LIST OF FIGURES

    FIGURE NO. FIGURE NAME PAGENO.

    1.1 MPPT TECHNIQUE WITH SOLAR CELL 9

    2.1 DIFFERENT SOLAR MODULES 11

    2.2 SCHEMATIC CROSS-SECTION OF A TYPICAL 11

    SOLAR CELL

    2.3 EQUIVALENT CIRCUIT OF PV CELL 12

    2 SUBSYSTEM1

    3 CIRCUIT UNDER SUBSYSTEM1

    4 SUBSYSTEM2

    5 CIRCUIT UNDER SUBSYSTEM2

    6 SUBSYSTEM3

    7 CIRCUIT UNDER SUBSYSTEM3

    8 SUBSYSTEM4

    9 CIRCUIT UNDER SUBSYSTEM4

    10 SUBSYSTEM5

    11 CIRCUIT UNDER SUBSYSTEM5

    12 SUBSYSTEM6

    13 CIRCUIT UNDER SUBSYSTEM6

    14 INTERCONNECTION OF ALL 6

    SUBSYSTEMS

    15 SIMULINK MODELOF PV MODULE

    16(a) INPUT TIME VARYING IRRADIATION

    16(b) INPUT CONSTANT TEMPERATURE-25 C

    16(c) OUTPUT I-V CHARACTERISTICS WITH

    VARYING IRRADIATION

    16(d) OUTPUT P-V CHARACTERISTICS

    WITH VARYING IRRADIATION

    17(a) INPUT TIME VARYING TEMPERATURE

    17(b) OUTPUT I-V CHARACTERISTICS WITH

  • xi

    VARYING TEMPERATURE

    17(c) OUTPUT P-V CHARACTERISTICS

    WITH VARYING TEMPERATURE

    17(d) OUTPUT POWER VS TIME

    3.1 CIRCUIT DIAGRAM OF A BOOST

    CONVERTER 29

    3.2 MODE 1 OPERATION OF THE BOOST

    CONVERTER 29

    3.3 MODE 2 OPERATION OF THE BOOST

    CONVERTER 30

    3.4 MODELLING OF Boost DC-DC

    CONVERTER 30

    4.1 FLOWCHART OF PERTURB & OBSERVE

    ALGORITHM 37

    4.2 MODELLING OF P&O ALGORITHM

    4.3 COMPLETE MODEL OF PV PANEL WITH

    MPPT 37

    4.4 OUTPUT CHARACTERISTICS 37

    4.5 IINCREMENTAL CONDUCTANCE MPPT

    FLOW CHART 38

    4.6 MODELLING OF INCREMENTAL

    CONDUCTANCE ALGORITHM 38

    4.7 COMPLETE MODEL OF PV PANEL

    WITH MPPT 38

    4.8 OUTPUT CHARACTERISTICS 38

    4.9 FLOWCHART FOR SHORT CICUIT

    CURRENT ALGORITHM 40

    4.10 COMPLETE MODEL OF PV PANEL WITH

    MPPT 40

    4.11 OUTPUT CHARACTERISTICS 40

    4.12 FLOWCHART FOR OPEN CIRCUIT

    VOLTAGE ALGORITHM 41

    4.13 COMPLETE MODEL OF PV PANEL WITH

    MPPT 41

  • xii

    4.14 OUTPUT CHARACTERISTICS 42

    5.1 HARDWARE SETUP 45

    5.1.1 WITHOUT BOOST CONVERTER 46

    5.1.2 WITH BOOST CONVERTER

    OPERATING 46

    5.1.3 BOOST CONVERTER 46

    5.1.4 GATE DRIVE CIRCUIT 47

    5.1.5 ARDUINO 47

  • 1

    CHAPTER 1

    INTRODUCTION

    It's certainly clear that fossil fuels are mangling the climate and that the status

    quo is unsustainable. There is now a broad scientific consensus that the world

    needs to reduce greenhouse gas emissions more than 25 percent by 2020 -- and

    more than 80 percent by 2050. The idea of harnessing the suns power has been

    around for ages.

    The basic process is simple. Solar collectors concentrate the sunlight that falls

    on them and convert it to energy. Solar power is a feasible way to supplement

    power in cities. In rural areas, where the cost of running power lines increases.

    Solar power, a clean renewable resource with zero emission, has got tremendous

    potential of energy which can be harnessed using a variety of devices. With

    recent developments, solar energy systems are easily available for industrial and

    domestic use with the added advantage of minimum maintenance. Solar energy

    could be made financially viable with government tax incentives and rebates.

    An exclusive solar generation system of capacity 250KWh per month would

    cost around Rs. 20 lakhs, with present pricing and taxes (2013). Most of the

    developed countries are switching over to solar energy as one of the prime

    renewable energy source.

    1.1 THE NEED FOR RENEWABLE ENERGY

    Renewable energy is the energy which comes from natural resources such as

    sunlight, wind, rain, tides and geothermal heat. These resources are renewable

    and can be naturally replenished. Therefore, for all practical purposes, these

    resources can be considered to be inexhaustible, unlike dwindling conventional

    fossil fuels. The global energy crunch has provided a renewed impetus to the

  • 2

    growth and development of Clean and Renewable Energy sources. Clean

    Development Mechanisms (CDMs) are being adopted by organizations all

    across the globe. Apart from the rapidly decreasing reserves of fossil fuels in the

    world, another major factor working against fossil fuels is the pollution

    associated with their combustion. Contrastingly, renewable energy sources are k

    known to be much cleaner and produce energy without the harmful effects of

    pollution unlike their conventional counterparts.

  • 3

    1.2 DIFFERENT SOURCES OF RENEWABLE ENERGY

    1.2.1 WIND POWER

    Wind turbines can be used to harness the energy available in airflows. Current

    day turbines range from around 600 kW to 5 MW of rated power. Since the

    power output is a function of the cube of the wind speed, it increases rapidly

    with an increase in available wind velocity. Recent advancements have led to

    aerofoil wind turbines, which are more efficient due to a better aerodynamic

    structure.

    1.2.2 SMALL HYDROPOWER

    Hydropower installations up to 10MW are considered as small hydropower and

    counted as renewable energy sources. These involve converting the potential

    energy of water stored in dams into usable electrical energy through the use of

    water turbines. Run-of-the-river hydroelectricity aims to utilize the kinetic

    energy of water without the need of building reservoirs or dams.

    1.2.3 BIOMASS

    Plants capture the energy of the sun through the process of photosynthesis. On

    combustion, these plants release the trapped energy. This way, biomass works as

    a natural battery to store the suns energy and yield it on requirement.

    1.2.4 GEOTHERMAL

    Geothermal energy is the thermal energy which is generated and stored within

  • 4

    the layers of the Earth. The gradient thus developed gives rise to a continuous

    conduction of heat from the core to the surface of the earth. This gradient can be

    utilized to heat water to produce superheated steam and use it to run steam

    turbines to generate electricity. The main disadvantage of geothermal energy is

    that it is usually limited to regions near tectonic plate boundaries, though recent

    advancements have led to the propagation of this technology.

    1.2.5 SOLAR POWER

    The tapping of solar energy owes its origins to the British astronomer John

    Herschel who famously used a solar thermal collector box to cook food during

    an expedition to Africa. Solar energy can be utilized in two major ways. Firstly,

    the captured heat can be used as solar thermal energy, with applications in space

    heating. Another alternative is the conversion of incident solar radiation to

    electrical energy, which is the most usable form of energy. This can be achieved

    with the help of solar photovoltaic cells or with concentrating solar power

    plants.

    As the Photovoltaic module exhibits non-linear V-I Characteristics, which are

    dependent on solar Insolation and environment factors, the development of an

    accurate power electronic circuit oriented model is essential to simulate and

    design the photovoltaic integrated system. In this paper, the design of PV

    system using simple circuit model with detailed circuit modelling of PV module

    using MATLAB/Simulink and the physical equations governing the PV module

    is presented.

  • 5

    1.3 LITERATURE REVIEW

    Studies show that a solar panel converts 21-40% of energy incident on it to

    electrical energy. A Maximum Power Point Tracking algorithm is necessary to

    increase the efficiency of the solar panel.

    There are different techniques for MPPT such as Perturb and Observe (hill

    climbing method), Incremental conductance, Fractional Short Circuit Current,

    Fractional Open Circuit Voltage, Fuzzy Control, Neural Network Control etc.

    Among all the methods Perturb and observe (P&O) and Incremental

    conductance are most commonly used because of their simple implementation,

    lesser time to track the MPP and several other economic reasons.

    Under abruptly changing weather conditions (irradiance level) as MPP changes

    continuously, P&O takes it as a change in MPP due to perturbation rather than

    that of irradiance and sometimes ends up in calculating wrong MPP. However

    this problem gets avoided in Incremental Conductance method as the algorithm

    takes two samples of voltage and current to calculate MPP. However, instead of

    higher efficiency the complexity of the algorithm is very high compared to the

    previous one and hence the cost of implementation increases. So we have to

    mitigate with a trade-off between complexity and efficiency.

    It is seen that to get maximum efficiency we are getting which type of

    converter. We are choosing here boost converter because it provide us more

    voltage at output then input. We can also choose buck-boost converter but due

    to our simplification and requirement we are selecting boost converter. It is

    very simple to implement and has high efficiency both under stationary and

    time varying atmospheric conditions.

  • 6

    N. Pandiarajan and Ranganath Muth, This paper presents a unique step-by-

    step procedure for the simulation of photovoltaic modules with Matlab/

    Simulink. One-diode equivalent circuit is employed in order to investigate I-V

    and P-V characteristics of a typical 36 W solar module. The proposed model is

    designed with a user-friendly icons and a dialog box like Simulink block

    libraries [1].

    Alpesh P. parekh, Bhavarty N. Vaidya and Chirag T. Patel, In this paper, the

    design of PV system using simple circuit model with detailed circuit modelling

    of PV module is presented. In this paper, Equivalent circuit of the PV module &

    Simulink model for each equation has presented and complete circuit oriented

    model has also presented [2].

    Pandiarajan N, Ramaprabha R and Ranganath Muthu, Circuit model of

    photovoltaic (PV) module is presented in this paper that can be used as a

    common platform for the material scientists as well as power electronic circuit

    designers to develop the better PV power plant. Detailed modeling procedure

    for the circuit model with numerical dimensions is presented using power

    system block set of MATLAB/ Simulink. The developed model is integrated

    with DC-DC boost converter with closed loop control of maximum power point

    tracking (MPPT) algorithm. The simulation results are validated with the

    experimental set up [3].

    P.Sathya, Dr.R.Natarajan, this paper presents the design and implementation

    of high performance closed loop Boost converter for solar powered HBLED

    lighting system. The proposed system consists of solar photovoltaic module, a

    closed loop boost converter and LED lighting module. The closed loop boost

    converter is used to convert a low level dc input voltage from solar PV module

  • 7

    to a high level dc voltage required for the load. To regulate the output of the

    converter, closed loop voltage feedback technique is used. The feedback voltage

    is compared with a reference voltage and a control signal is generated and

    amplified. The amplified signal is fed to 555 Timer which in turn generates a

    PWM signal which controls the switching of MOSFET. Thus by switching of

    MOSFET it would try to keep output as constant. Initially the boost converter,

    timer circuit, amplifier circuit and LED light circuits are designed, simulated

    and finally implemented in printed circuit board. The simulation studies are

    carried out in MULTISIM. The experimental results for solar PV and boost

    converter obtained in both software and hardware was presented in this paper

    [7].

    Vandana Khanna, Bijoy Kishore Das, Dinesh Bisht, A Simulation model for

    simulation of a single solar cell and two solar cells in series has been developed

    using Simelectronics (Matlab/Simulink) environment and was presented in this

    paper. A solar cell block is available in simelectronics, which was used with

    many other blocks to plot I-V and P-V characteristics under variations of

    parameters considering one parameter variation at a time. The effect of variation

    of parameters such as series resistance, Rs, shunt resistance Rsh, diode

    parameters: diode saturation current, Is and ideality factor, N, could be seen on

    the characteristics of a single solar cell. Effect of two environmental parameters

    of temperature and irradiance variations could also be observed from simulated

    characteristics. Matlab coding has been done to find the maximum power

    output, Pm, and voltage at maximum power output, Vm, of a single solar cell

    and two solar cells (in series) under different values of parameters. The Pmand

    Vm values are tabulated here in this paper for variation of one parameter at a

    time, considering the diode parameters: Is and N, resistances: series and shunt,

    temperature and irradiance [5].

  • 8

    G. Venkateswarlu and Dr.P.Sangameswar Raju, The study of photovoltaic

    systems in an efficient manner requires a precise knowledge of the IV and PV

    characteristic curves of photovoltaic modules. A Simulation model for

    simulation of a single solar cell and two solar cells in series has been developed

    using Sim electronics (Mat lab /Simulink) environment and is presented here in

    this paper. A solar cell block is available in simelectronics, which was used with

    many other blocks to plot I-V and P-V characteristics under variations of

    parameters considering one parameter variation at a time. Effect of two

    environmental parameters of temperature and irradiance variations could also be

    observed from simulated characteristics [4].

    1.4 OBJECTIVE

    The basic objective would be to study MPPT and successfully implement the

    MPPT algorithms either in code form as well as using the Simulink/Simscape

    model. Modelling of the solar cell in Simulink/Simscape and interfacing both

    with the MPPT algorithm to obtain the maximum power point operation would

    be of prime importance. After simulating our result with the help of

    Simulink/Simscape we would like to implement it on hardware using Field

    Programmable Gate Array (FPGA).

    Fig.1.1 MPPT Technique with Solar Cell

  • 9

    1.5 FUTURE SCOPE OF RENEWABLE ENERGY RESOURCES

    The current trend across developed economies tips the scale in favour of

    Renewable Energy. For the last three years, the continents of North America and

    Europe have embraced more renewable power capacity as compared to

    conventional power capacity. Renewables accounted for 60% of the newly

    installed power capacity in Europe in 2009 and nearly 20% of the annual power

    production

    1.6 THESIS OUTLINE

    This thesis has been broadly divided into 7 chapters. The first one being the

    introduction, chapter 2 is on photovoltaic effect and modelling of solar cell with

    Matlab Simulink/Simscape and effect of load mismatching. In chapter 3 we will

    study about Boost Converter. Chapter 4 is on maximum power point tracking

    and study of the various algorithms. Chapter 5 will discuss about FPGA &

    Hardware Implementation. Result and conclusion is discussed in chapter 6 & 7.

  • 10

    CHAPTER 2

    MODELLING OF PV PANEL

    2.1 PHOTOVOLTAIC CELL

    A photovoltaic cell or photoelectric cell is a semiconductor device that converts

    light to electrical energy by photovoltaic effect. If the energy of photon of light

    is greater than the band gap then the electron is emitted and the flow of

    electrons creates current.

    However a photovoltaic cell is different from a photodiode. In a photodiode

    light falls on n-channel of the semiconductor junction and gets converted into

    current or voltage signal but a photovoltaic cell is always forward biased.

    2.2 PV MODULE

    Usually a number of PV modules are arranged in series and parallel to meet the

    energy requirements. PV modules of different sizes are commercially available

    (generally sized from 60W to 170W). For example, a typical small scale

    desalination plant requires a few thousand watts of power

    2.3 PV ARRAY

    A PV array consists of several photovoltaic cells in series and parallel

    connections. Series connections are responsible for increasing the voltage of the

    module whereas the parallel connection is responsible for increasing the current

    in the array.

  • 11

    Fig.2.1 Different Solar Modules

    2.4 PV MODELLING

    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.3 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.

  • 12

    Fig.2.2 Schematic Cross-Section of a Typical Solar Cell

    The most important component that affects the accuracy of the simulation is the

    PV cell model. Modelling of PV cell involves the estimation of the I-V and P-V

    characteristics curves to emulate the real cell under various environmental

    conditions. An ideal solar cell is modelled by a current source in parallel with a

    diode. However no solar cell is ideal and thereby shunt and series resistances

    are added to the model as shown in the Fig.4

    Fig.2.3 Equivalent Circuit of PV Cell

    The current source Ipv represents the cell photo current, Rsh and Rs are used to

    represent the intrinsic series and shunt resistance of the cell respectively.

    Usually the value of Rsh is very large and that of Rs is very small, hence they

    may be neglected to simplify the analysis.

    2.4.1.NOMENCLATURE

    Vpv is output voltage of a PV module (V) Ipv is output current of a PV module

    (A)

    Tr is the reference temperature = 298 K

    T is the module operating temperature in Kelvin

    Iph is the light generated current in a PV module (A) Io is the PV module

    saturation current (A)

    A = B is an ideality factor = 1.6

    k is Boltzman constant = 1.3805 10-23

    J/K q is Electron charge = 1.6 10-19

    C

    Rs is the series resistance of a PV module

  • 13

    ISCr is the PV module short-circuit current at 25 oC and 1000W/m

    2 = 2.55A

    Ki is the short-circuit current temperature co-efficient at ISCr = 0.0017A / oC

    is the PV module illumination (W/m2) = 1000W/m2

    Ego is the band gap for silicon = 1.1 Ev

    Ns is the number of cells connected in series Np is the number of cells connected

    in parallel

    2.4.2.INTRODUCTION

    Among the renewable energy resources, the energy due to the photovoltaic (PV)

    effect can be considered the most essential and prerequisite sustainable resource

    because of the ubiquity, abundance, and sustainability of solar radiant energy.

    Regardless of the intermittency of sunlight, solar energy is widely available

    and is free. Recently, photovoltaic system is recognized to be in the forefront in

    renewable electric power generation. It can generate direct current electricity

    without environmental impact and contamination when exposed to solar

    radiation. Being a semiconductor device, the PV system is static, quiet, free of

    moving parts, and has little operation and maintenance costs.

    PV module represents the fundamental power conversion unit of a PV

    generator system. The output characteristics of a PV module depend on the solar

    insolation, the cell temperature and the output voltage of the PV module. Since

    PV module has nonlinear characteristics, it is necessary to model it for the

    design and simulation of maximum power point tracking (MPPT) for PV

    system applications.

    Mathematical modeling of PV module is being continuously updated to enable

    researcher to have a better understanding of its working. [1]- [6]

    In this paper, a step-by-step procedure for simulating PV module with

  • 14

    subsystem blocks, with user-friendly icons and dialog in the same way as

    Matlab/ Simulink block libraries is developed. Section III presents the PV

    module equivalent circuit and equations for Ipv, the output current from the PV

    module. The reference model presented in section IV provides data for Solkar

    make 36 W PV module for simulation. In section V, the step-by-step modeling

    procedure of PV module is presented with simulation results. Finally, brief

    conclusions are drawn in Section VI.

    2.4.3.MATHEMATICAL MODEL FOR A PHOTOVOLTAIC MODULE

    A solar cell is basically a p-n junction fabricated in a thin wafer of

    semiconductor. The electromagnetic radiation of solar energy can be directly

    converted to electricity through photovoltaic effect. Being exposed to the

    sunlight, photons with energy greater then the band-gap energy of the

    semiconductor creates some electron-hole pairs proportional to the incident

    irradiation.

    The current source Iph represents the cell photocurrent. Rsh and Rs are the

    intrinsic shunt and series resistances of the cell, respectively. Usually the value

    of Rsh is very large and that of Rs is very small, hence they may be neglected to

    simplify the analysis.

    PV cells are grouped in larger units called PV modules which are further

    interconnected in a parallel-series configuration to form PV arrays.

    The photovoltaic panel can be modeled mathematically as given in equations

    (1)- (4) [3] [5].

    Module photo-current:

    I ph [I SCr K i (T 298)] * /1000 (1)

    Module reverse saturation current - Irs:

  • 15

    I rs I SCr /[exp(qVOC / N S kAT ) 1] (2)

    The module saturation current I0 varies with the cell

    temperature, which is given by

    T 3 q * Eg 0 1 1

    I

    0

    I

    rs

    [ ] exp[ ] (3)

    Tr Bk T

    r T

    2.4.4.REFERENCE MODEL

    Solar make 36 W PV module is taken as the reference module for simulation

    and the name-plate details are given in Table 1.

    TABLE 2.1: ELECTRICAL CHARACTERISTICS DATA OF

    SOLAR 36W PV MODULE

    Rated Power 37.08 W

    Voltage at Maximum power (Vmp) 16.56 V

    Current at Maximum power ( Imp) 2.25 A

    Open circuit voltage ( VOC) 21.24 V

    Short circuit current ( ISCr) 2.55 A

    Total number of cells in series (Ns) 36

    Total number of cells in parallel (Np) 1

    Note: The electrical specifications are under test conditions of irradiance of 1

    kW/m2, spectrum of 1.5 air mass and cell temperature of 25

    oC.

    2.4.5.STEP BY STEP PROCEDURE FOR SIMULINK MODELING OF

    PV MODULE

    A model of PV module with moderate complexity that includes the temperature

  • 16

    independence of the photocurrent source, the saturation current of the diode,

    and a series resistance is considered based on the Shockley diode

    equation.Being illuminated with radiation of sunlight, PV cell converts part of

    the photovoltaic potential directly into electricity with both I-V and P-V output

    characteristics.Using the equations given in section III, simulink modeling is

    done in the following steps

    A. Step 1

    Subsystem 1 is shown in Figure 1. This model converts the module operating

    temperature given in degrees Celsius to Kelvin.

    B. Step 2

    Subsystem 2 is shown in Figure 4. This model takes following inputs.

    Insolation/ Irradiation (G / 1000) 1 kW/ m2 = 1.

    Module operating temperature TaK = 30 to 70oC

    Module reference temperature TrK = 25oC.

  • 17

    Short circuit current (ISC) at reference temp. = 2.55A

    Fig 4.SUBSYSTEM2

    This model calculates the short circuit current ( ISC) at given operating

    temperature. Figure 5 gives the circuit under subsystem

    C. Step 3

    Subsystem 3 is shown in Figure 6. This model takes short circuit current ISC at

    reference temp. = 2.55A and Module reference temperature TrK = 25oC as

    input.

  • 18

    Using equation 2, the reverse saturation current of the diode is calculated in

    subsystem 3. Figure 7 gives the circuit under subsystem 3.

    D. Step 4

    Subsystem 4 is shown in Figure 8.

  • 19

    This model takes reverse saturation current Irs, Module reference temperature

    TrK = 250 C and Module operating temperature TaK as input and calculates

    module saturation current. Figure 9 gives the circuit under subsystem 4.

    E. Step 5

    Subsystem 5 is shown in Figure 10.

    This model takes operating temperature in Kelvin TaK and calculates the

  • 20

    product NsAkT, the denominator of the exponential function in equation (4).

    Figure 11 gives the circuit under subsystem 5.

    F. Step 6

    Subsystem 6 is shown in Figure 12.

    This model executes the function given by the equation (4). The following

    function equation is used.

    IPV = u(3)-u(4)*(exp((u(2)*(u(1)+u(6)))/(u(5)))-1)

    Figure 13 gives the circuit under subsystem 6.

  • 21

    G. Step 7

    All above six models are interconnected as given in Figure 14.

    Figure 14. Interconnection of all six subsystems

    The final model is shown in Figure 15. The workspace is added to measure Ipv,

    Vpv, Ppv in this model. The time tout is stored in workspace with scope model

    can be used to plot graph.

  • 22

    The final model takes irradiation, operating temperature in Celsius and module

    voltage as input and gives the output current Ipv and output voltage Vpv.

    Matlab code for plotting XY graph is given below.

    plot (Vpv,Ipv)

    plot (Vpv, Ppv)

    The code for plotting scope signals is

    plot(tout,Ipv)

    H. Performance Estimation

    With the developed model, the PV module characteristic is estimated as follows.

    (i) I-V and P-V characteristics under varying

    irradiation with constant temperature are obtained as shown in Figures 16(a) to

    16(d).

    1. In Figure 16(a), the input irradiation is shown. Between 0 and 1 s, the

    irradiation is 200W/m2, between 1 and 2 s it is 600 W/m, while from 2 s

    onwards it is 1000W/m2.

  • 23

    4. The P-V output characteristics of PV module with varying irradiation at

  • 24

    constant temperature are shown in Figure 16(d).

    _ The above graphs are user friendly.

    _ When the irradiation increases,

    _ The current output increases

    _ The voltage output also increases. This results in net increase in power output

    with increase in irradiation at constant temperature.

    (ii) I-V and P-V Characteristics under constant irradiation with varying

    temperature are obtained in Figures 17(a) to 17(d).

    1. In Figure 17(a) the time varying temperature signal is shown. Between 0 and

    1 second, the temperature of 250C is applied and it is increased to 50 and 750C.

  • 25

    2. The I-V output characteristics of PV module with varying temperature at

    constant irradiation of 1000W/m2 are shown in Figure 17(b).

    3. The P-V output characteristics of PV module with varying temperature at

    constant irradiation are shown in Figure 17(c).

    4. The output power vs. time of PV module is shown in Figure 17(d). The

    power output reduces with increase in temperature at constant irradiation.

  • 26

    _ When the operating temperature increases,

    _ The current output increases marginally

    _ But the voltage output decreases drastically

    _ Results in net reduction in power output with rise in temperature

    The results are verified and found matching with the manufacturers data sheet

    output curves.

    2.4.6. CONCLUSIONS

    The step-by-step procedure for modeling the PV module is presented.

    Thismathematical modeling procedure serves as an aid to induce more people

    into photovoltaic research and gain a closer understanding of I-V and P-V

    characteristics of PV module.

    REFERENCES

    [1] M.Veerachary,Power Tracking for Nonlinear PV Sources with Coupled

    Inductor SEPIC Converter, IEEE Transactions on Aerospace and Electronic

    Systems, vol. 41, No. 3, July 2005.

    [2] I. H. Altas and A.M. Sharaf, A Photovoltaic Array Simulation Model for

    Matlab-Simulink GUI Environment, IEEE, Clean Electrical Power,

    International Conference on Clean Electrical Power (ICCEP '07), June 14-16,

  • 27

    2007, Ischia, Italy.

    [3] S.Chowdhury, S.P.Chowdhury, G.A.Taylor, and Y.H.Song, Mathematical

    Modeling and Performance Evaluation of a Stand-Alone Polycrystalline PV

    Plant with MPPT Facility, IEEE Power and Energy Society General Meeting -

    Conversion and Delivery of Electrical Energy in the 21st Century, July 20-24,

    2008, Pittsburg, USA.

    [4] Jee-Hoon Jung, and S. Ahmed, Model Construction of Single Crystalline

    Photovoltaic Panels for Real-time Simulation, IEEE Energy Conversion

    Congress & Expo, September 12-16, 2010, Atlanta, USA.

    [5] S. Nema, R.K.Nema, and G.Agnihotri, Matlab / simulink based study of

    photovoltaic cells / modules / array and their experimental verification,

    International Journal of Energy and Environment, pp.487- 500, Volume 1, Issue

    3, 2010.

  • 28

    CHAPTER 3

    BOOST CONVERTER

    A boost converter is designed to step up a fluctuating or variable input voltage

    to a constant output voltage of 24 volts with input range of 6-23volts in. To

    produce a constant output voltage feedback loop is used. The output voltage is

    compared with a reference voltage and a PWM wave is generated, here Spartan

    6 FPGA kit is used to generate PWM signal to control switching action.

    A DC to DC converter is used to step up from 12V to 24V. The 12V input

    voltage is from the battery storage equipment and the 24V output voltage serves

    as the input of the inverter in solar electric system. In designing process, the

    switching frequency, f is set at 20 kHz and the duty cycle, D is 50%.

    Here we want to introduced an approach to design a boost converter for

    photovoltaic (PV) system using microcontroller. The converter is designed to

    step up solar panel voltage to a stable 24V output without storage elements such

    as battery. It is controlled by a FPGA unit using voltage-feedback technique.

    The output of the boost converter is tracked, measured continuously and the

    values are sent to the microcontroller unit to produce pulse-width-modulation

    (PWM) signal. The PWM signal is used to control the duty cycle of the boost

    converter. Typical application of this boost converter is to provide DC power

    supply for inverter either for grid-connected or standalone system. Simulation

    and experimental results describe the performance of the proposed design.

    Spartan 6 FPGA is used to perform tasks in the proposed design.

    As stated in the introduction, the maximum power point tracking is basically a

    load matching problem. In order to change the input resistance of the panel to

  • 29

    match the load resistance (by varying the duty cycle), a DC to DC converter is

    required.

    It has been studied that the efficiency of the DC to DC converter is maximum

    for a buck converter, then for a buck-boost converter and minimum for a boost

    converter but as we intend to use our system either for tying to a grid or for a

    water pumping system which requires 230 Vat the output end, so we use a boost

    converter.

    Fig.3.1 Circuit Diagram of a Boost Converter

    3.1. MODE 1 OPERATION OF THE BOOST CONVERTER When the switch is closed the inductor gets charged through the battery and

    stores the energy.In this mode inductor current rises(exponentially) but for

    simplicity we assume that the charging and the discharging of the inductor are

    linear.The diode blocks the current flowing and so the load current remains

    constant which is being supplied due to the discharging of the capacitor.

    Fig.3.2 Mode 1 Operation of the Boost Converter

    3.2. MODE 2 OPERATION OF THE BOOST CONVERTER In mode 2 the switch is open and so the diode becomes short circuited. The

    energy stored in the inductor gets discharged through opposite polarities which

    charge the capacitor. The load current remains constant throughout the

  • 30

    operation. The waveform for a boost converter are shown in figure.

    Fig.3.3 Mode 2 Operation of the Boost Converter 3.3. MODELING OF BOOST CONVERTER USING MATLAB SIMSACPE

    Fig.3.4 Modelling of Boost DC-DC Converter

    3.4. DESIGN APPROACH OF PROPOSED BOOST CONVERTER Load Requirement: The load is a simple 4 x 4 LED panel and each row

    containing 4 LED in a line would require a current of 10- 15 mA and thus total

    of 60 mA to all four branches and thus having a resistance of 570. As each

    LED gives a drop of 2.1 volts to become forward biased, so a minimum of 8.4

  • 31

    volts is required to glow 4 LED in series, for this a voltage of 24 V is required

    to be supplied to LEDs. Thus the load requirement is 570 with 42 mA of total

    current thus required voltage was 24 V. Since a potential divider is used whose total resistance is 1100 so total

    equivalent resistance is Req = (1100) (570) = 375.Based on this load

    requirement the other parameters would be calculated and the specifications are

    tabulated in the following table.

    Table 3.1 Specification for Boost Converter

    S.No. Component Value

    1 Inductor 290H 2 MOSFET 1N5408 IRF 840 3 Power Diode IN5408 4 Input Capacitor 470F 5 Output Capacitor 330 F 6 Resistive Load 50, 50W

    Duty Cycle: The duty cycle can be found using the following relation-

    D=1

    Inductor value: The value of inductor is determined using the following relation Lmin=D (1-D

    2)*R/2*Fs

    An inductor is practically designed using the following parameters and is shown

    in the figure 22.

    Formula for inductor design, L = (d2n2) / (l + 0.45d)

    Required dimensions of inductor Coil length, l= 8.1 cm

    Diameter, d= 6.3 cm Inductance value required, L= 151 H Number of turns, n=64

  • 32

    Where L is inductance in micro Henrys, d

    is coil diameter in meters, l is coil length in meters, and n is

    number of turns

    Capacitor value: The value of capacitor is determined from the following equation

    C=D/Fs*R*Vr Where C is the minimum value of capacitance,

    D is duty cycle, R is output resistance, Fs is switching frequency, and Vr is output voltage ripple factor.

  • 33

    CHAPTER 4

    MAXIMUM POWER POINT TRACKING ALGORITHM

    4.1. AN OVERVIEW OF MAXIMUM POWER POINT TRACKING

    A typical solar panel converts only 30 to 40 percent of the incident solar

    irradiation into electrical energy. Maximum power point tracking technique is

    used to improve the efficiency of the solar panel. According to Maximum

    Power Transfer theorem, the power output of a circuit is maximum when the

    Thevenin impedance of the circuit (source impedance) matches with the load

    impedance. Hence our problem of tracking the maximum power point reduces

    to an impedance matching problem. In the source side we are using a boost

    convertor connected to a solar pan el in order to enhance the output voltage so

    that it can be used for different applications like motor load. By changing the

    duty cycle of the boost converter appropriately we can match the source

    impedance with that of the load impedance.

    4.2. DIFFERENT MPPT TECHNIQUES There are different techniques used to track the maximum power point. Few of

    the most popular techniques are:

    1) Perturb and Observe (hill climbing method)

    2) Incremental Conductance method 3) Fractional short circuit current 4) Fractional open circuit voltage

    4.3 PERTURB & OBSERVE

    Perturb & Observe (P&O) is the simplest method. In this we use only one

    sensor, that is the voltage sensor, to sense the PV array voltage and so the cost

  • 34

    of implementation is less and hence easy to implement. The time complexity of

    this algorithm is very less but on reaching very close to the MPP it doesnt stop

    at the MPP and keeps on perturbing on both the directions. When this happens

    the algorithm has reached very close to the MPP and we can set an appropriate

    error limit or can use a wait function which ends up increasing the time

    complexity of the algorithm. However the method does not take account of the

    rapid change of irradiation level (due to which MPPT changes) and considers it

    as a change in MPP due to perturbation and ends up calculating the wrong MPP.

    To avoid this problem we can use incremental conductance method.

    4.4. INCREMENTAL CONDUCTANCE

    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 eliminated. However 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 complicated system. This is the reason that

    Perturb and Observe and Incremental Conductance method are the most widely

    used algorithms. Owing to its simplicity of implementation we have chosen the

    Perturb & Observe algorithm for our study among the two.

  • 35

    4.5. FRACTIONAL OPEN CIRCUIT VOLTAGE

    The near linear relationship between VMPP and VOC of the PV array, under varying

    irradiance and temperature levels, has given rise to the fractional VOC method.

    VMPP = k1 Voc where k1 is a constant of proportionality. Since k1 is dependent on the

    characteristics of the PV array being used, it usually has to be computed

    beforehand by empirically determining VMPP and VOC for the specific PV array at

    different irradiance and temperature levels. The factor k1 has been reported to be

    between 0.71 and 0.78. Once k1 is known, VMPP can be computed with VOC

    measured periodically by momentarily shutting down the power converter.

    However, this incurs some disadvantages, including temporary loss of power.

    4.6. FRACTIONAL SHORT CIRCUIT CURRENT Fractional ISC results from the fact that, under varying atmospheric conditions, IMPP

    is approximately linearly related to the ISC of the PV array.

    IMPP =k2 Isc

    Where k2 is a proportionality constant. Just like in the fractional VOC technique, k2

    has to be determined according to the PV array in use. The constant k2 is generally

    found to be between 0.78 and 0.92. Measuring ISC during operation is problematic.

    An additional switch usually has to be added to the power converter to periodically

    short the PV array so that ISC can be measured using a current sensor.

    4.7. DETAILS OF PERTURB & OBSERVE ALGORITHM

    The Perturb & Observe algorithm states that when the operating voltage of

    the PV panel is perturbed by a small increment,if the resulting change in power P is

    positive,then we are going in the dir of perturbationection of MPP and we keep on

  • 36

    perturbing in the same direction.If P is negative,we are going away from the

    direction of MPP and the sign of perturbation supplied has to be changed.

    The flowchart for the P&O algorithm is shown in the figure

    Fig.4.1 Flowchart Of Perturb & Observe Algorithm

    4.7.1. MODELLING OF P&O ALGORITHM

    Fig.4.2 Modelling of P&O Algorithm

  • 37

    4.7.2. COMPLETE MODEL OF PV PANEL WITH MPPT

    Fig.4.3 Complete Model of PV Panel With MPPT

    4.7.3 OUTPUT CHARACTERISTICS

    FIG 4.4 OUTPUT CHARACTERISTICS

  • 38

    4.8 DETAILS OF INCREMENTAL CONDUCTANCE ALGORITHM

    The flowchart for the Incremental Conductance algorithm is shown in the figure

    Fig-4.5:Incremental conductance MPPT Flow chart

  • 39

    4.8.1. MODELLING OF INCREMENTAL CONDUCTANCE

    ALGORITHM

    Fig.4.6 Modelling of Incremental Conductance Algorithm

    4.8.2. COMPLETE MODEL OF PV PANEL WITH MPPT

    Fig.4.7 Complete Model of PV Panel With MPPT

  • 40

    4.8.3 OUTPUT CHARACTERISTICS

    PV CELL OUTPUT INC CONDUCTANCE OUTPUT

    FIG 4.8 OUTPUT CHARACTERISTICS

    4.9 DETAILS OF SHORT CIRCUIT CURRENT ALGORITHM

    The flowchart for the Short Circuit Current algorithm is shown in the figure

    FIG 4.9 FLOWCHART FOR SHORT CICUIT CURRENT ALGORITHM

  • 41

    4.9.1. COMPLETE MODEL OF PV PANEL WITH MPPT(SHORT CIRCUIT

    CURRENT)

    Fig.4.10 Complete Model of PV Panel With MPPT

    4.9.2 OUTPUT CHARACTERISTICS

    PV CELL OUTPUT SHORT CIRCUIT CURRENT OUTPUT

    FIG 4.11 OUTPUT CHARACTERISTICS

  • 42

    4.9DETAILS OF FRACTIONAL OPEN CIRCUIT VOLTAGE ALGORITHM

    The flowchart for the Open Circuit Voltage algorithm is shown in the figure

    FIG 4.12 FLOWCHART FOR OPEN CIRCUIT VOLTAGE ALGORITHM

    4.9.1. COMPLETE MODEL OF PV PANEL WITH MPPT(OPEN CIRCUIT

    VOLTAGE)

    Fig.4.13 Complete Model of PV Panel With MPPT

  • 43

    4.9.2 OUTPUT CHARACTERISTICS:

    PV CELL OUTPUT OPEN CIRCUIT VOLTAGE OUTPUT

    FIG 4.14 OUTPUT CHARACTERISTICS

    4.10 COMPARISON OF MPPT ALGORITHMS:

    Comparing different parameters, it is evident that each algorithm is suited for

    different purposes. Below table shows a comparison between these algorithms.

    ERRORS P AND O INCREMENTAL

    CONDUCTANCE

    SHORT

    CIRCUIT

    CURRENT

    OPEN

    CIRCUIT

    VOLTAGE

    MEAN

    ABSOLUTE

    PERCENTAGE

    ERROR

    0.093780528

    0.00442

    0.098105

    0.578062

    MEAN

    PERCENTAGE

    ERROR

    9.3780528

    0.442

    9.8105

    57.8

    MEAN

    ABSOLUTE

    ERROR

    0.1

    0.002264999

    0.133459

    1.74725082

    TABLE 4.1 COMPARISON OF MPPT ALGORITHMS

  • 44

    Conclusion from the table 4.1

    Due to minimum error in Incremental Conductance,Incremental Conductance is

    the Optimum Algorithm.

    4.11 COMPLETE MODEL OF PV PANEL WITH MPPT(INCREMENTAL

    CONDUCTANCE) APPLIED TO UNIVERSAL MOTOR

  • 45

    CHAPTER 5

    HARDWARE IMPLEMENTATION

    5.1 Hardware Components

    The Components used for the project are listed in the Table 5.1

    Table 5.1 Hardware Components

    COMPONENT NAME SPECIFICATION

    Capacitor 470 F ,50 V

    Inductor ecore 22 SWG (0.5mH)

    Mosfet IRF 840

    Diode IN4007 , 3A

    Transformer 220/12 V

    Optocoupler IC TLP 250

    Resistors 460,1k,1.2 k

    Universal motor 240v,60Hz,,50-1000W

    Adruino

  • 46

    5.2 Hardware Setup

    The entire Hardware Setup for the project is Shown in the Figure 5.1

    Figure 5.1 Hardware SetupFIG 5.1.1 Without Boost Converter

    Fig 5.1.2With Boost Converter Operating

  • 47

    Fig 5.1.3 BOOST CONVERTER

    Fig 5.1.4 Gate Drive Circuit

    Fig 5.1.5 Arduino

  • 48

    5.3 Sub Circuits

    The entire hardware setup consists of the following sub circuits:

    1. Supply Circuit

    2. Control Circuit

    3. Optocoupler Circuit

    4. Power Circuit

    5.3.1 Supply Circuit

    The AC input supply is stepped down to 12 V from 230 V using a step down

    transformer. Using a diode bridge rectifier AC voltage is converted to DC voltage.

    5.3.2 Control Circuit

    The control circuit is used to produce the pulses to trigger the MOSFET of

    the boost converter.

    5.3.3 Optocoupler Circuit

    The optocoupler circuit is used to isolate the Power Circuit from Control

    Circuit. The supply of 12 V is given to the pin 5 and the output of the optocoupler

    is taken from pin 4 and it is used to trigger the MOSFET switch of the boost

    converter.

    5.3.4 Power Circuit

    The power circuit consists of consists of the boost converter whose

    output voltage greater than the input voltage depending on the boost mode of

    operation.

  • 49

    5.4 Matlab interface with Arduino for serial communication:

    MATLAB Support Package for Arduino(also referred as Arduino-I/O

    Package) allows us to communicate with an Arduino over a serial port.It

    consists of a MATLAB API on the host computer and a server program that

    runs on the Arduino.Together,they allow us to access transmit and receive serial

    data from Arduino.

    In this project we received data from Arduino such as solar current reading (I),

    solar voltage reading (V), solar power reading (P), time (in Sec) (T), battery

    voltage reading (Vb) and develop a real time plot of I-V, P-V on Matlab to monitor

    maximum power point of solar array And also plot graph of V, P, I, Vb

    with respect to time to check variation in this parameter.

    5.5 TESTING AND RESULT.

    The experimental test was recorded in Chennai, India. Perturb & observer and

    Incremental conductance algorithms based MPPT experiments are performed on

    these days to show the robustness to the varying atmosphere and compare their

    performances. We take real time reading on Matlab for 100 second and plot graph

    of I vs. V, P vs. V and also plot graph of P, V, I, Vb with respect to time. Results

    of perturb & observer method are shown in Fig-10 and Fig-11 in which Fig -10.

    has graph of solar power, solar voltage, solar current, battery voltage with respect

    to time from which we got instantaneous value of solar voltage, solar current, solar

    power with respect to time and in Fig-11 shows the graph of solar current versus

    solar voltage and solar power versus solar voltage which shows maximum power

    point generated by the solar panels when the solar charger was running the perturb

    and observer algorithm in which solar charger charges battery.

  • 50

    Similarly the Results of incremental conductance method are shown in Fig -12 and

    Fig -13 in which Fig -12 has graph of solar power, solar voltage, solar current,

    battery voltage with respect to time from which we would get instantaneous value

    of solar voltage, solar current, solar power with respect to

    time and in Fig -13 shows the graph of solar current versus solar voltage and solar

    power versus solar voltage which shows maximum power point generated by the

    solar panels when the solar charger was running the incremental conductance

    algorithm in which solar charger charges battery.

    Fig -10 and Fig -13 represents graphs of maximum power point tracker when

    battery is in bulk condition so it tracks the maximum power point algorithm. Fig -

    14 and Fig -15 represents graphs of maximum power point tracker when battery is

    in float condition. In this state we try and keep the battery voltage at 14 volt by

    decreasing the pwm value.

  • 51

    CHAPTER 6

    CONCLUSION AND FUTURE WORK

    Using MPPT with solar panel installations has clear advantages. The initial

    investment is smaller because smaller panel wattage is required (very little

    potential power is wasted), and adding correct battery-charging algorithms

    will also decrease operating costs (batteries are protected and last longer).

    In this project we present four MPPT algorithms implemented on a synchronous

    Boost converter and compare them on real time graph obtain in Matlab. From this

    we come to know that Incremental conductance method has less oscillation.The

    maximum power point tracker works because there is a difference between the

    solar panels MPP voltage and the batterys charging voltage. The IV curves for an

    actual solar panel show that the MPP voltage goes down as the temperature of the

    solar panel goes up, this means that the solar panels Maximum power point

    voltage is lower as the panel temperature rises. On the other hand, if the

    temperature of the solar panel is low and the battery is mostly discharged, the

    maximum power point tracker will show higher power gains. My experience with

    maximum Power point Tracking has shown that large power gains are possible

    only under ideal circumstances. If the solar panels are cool, the batteries mostly

    discharged and voltage drops in the system are low, maximum power point tracker

    gets higher efficiency should occur. Under other conditions the maximum power

    point tracker efficiency will be lower, especially if the solar panels are being used

    in hot conditions

  • 52

    REFERENCES:

    1.Arun KumarVerma, Bhim Singh and S.C Kaushik, An Isolated Solar Power

    Generation using Boost Converter and Boost Inverter, in Proc. National

    Conference on Recent Advances in Computational Technique in Electrical

    Engineering, SLITE, Longowal (India), 19-20 March, 2010, paper 3011, pp.1-8.

    2.Comparison of MPPT Algorithms for DC-DC Converters Based PV Systems by

    A.Pradeep Kumar Yadav,S.Thirumaliah,G.Haritha International Journal of

    Advanced Research in Electrical, Electronics and Instrumentation Engineering

    Vol. 1, Issue 1, July 2012

    3.Eftichios Koutroulis and Freder Blaabjerg , (2012), A New Technique

    for Tracking the Global Maximum Power Point of PV Arrays Operating

    Under Partial-Shading Conditions , IEEE Journal of Photovoltaics , Vol. 2 , No. 2,

    pp. 184-190.

    4.G. Acciari, D. Graci, and A. La Scala, (2011), Higher PV module efficiency

    by a novel CBS bypass, IEEE Trans. Power Electron, Vol. 26, No. 5, pp.

    13331336.

    5.G. Villalva, J. R. Gazoli, E. Ruppert F, "Modeling and circuit-based simulation

    of photovoltaic arrays", Brazilian Journal of Power Electronics, 2009 vol. 14, no.

    1, pp. 35-45, ISSN 1414-8862.

  • 53

    6.International Conference on Microelectronics, Communication and Renewable

    Energy (ICMiCR-2013)

    Experimental Implementation of Micro-controller based MPPT for Solar PV

    System Ahmed Bin-Halab,Adel Abdennour,Hussein Mashlay in-Halabi Adel

    Abdennour Hussein Mashaly Department of Electrical Engineering ,King Saud

    University ,Riyadh, Saudi Arabia.

    7.Mihnea Rosu-Hamzescu, Sergiu Opera Practical Guide to Implementing

    Solar Panel MPPT Algorithms"

    8.M. Miyatake, M. Veerachary, F. Toriumi, N. Fujii, and H. Ko, (2011)

    Maximum power point tracking of multiple photovoltaic arrays: A PSO

    approach, IEEE Trans. Aerosp. Electron. Syst., Vol. 47, No. 1, pp. 367380.

    9.M. Berrera, A. Dolara, R. Faranda and S. Leva, Experimental test of seven

    widely-adopted MPPT algorithms, 2009 IEEE Bucharest Power Tech Conference,

    June 28th - July 2nd, Bucharest, Romania.

    10.N.Pandiarajan and Ranganath Muth Mathematical Modeling of

    Photovoltaic Module with Simulink in 2011 1st International Conference on

    Electrical Energy Systems.

    11. N. Femia, G. Petrone, G. Spagnuolo and M. Vitelli, (2005)

    Optimization of and observe maximum power point tracking method, IEEE

    Trans. Power Electron., Vol. 20, No. 4, pp. 963973.

  • 54

    12.Nevzat Onat, Recent Developments inMaximumPower Point Tracking

    Technologies for Photovoltaic Systems, Hindawi Publishing Corporation

    International Journal of Photoenergy Volume 2010, Article ID 245316, 11 pages.

    13.Pandiarajan N, Ramaprabha R and Ranganath Muthu Application Of

    Circuit Model For Photovoltaic Energy Conversion System

    14.P.Sathya, Dr.R.Natarajan Design and Implementation of 12V/24V Closed

    loop Boost Converter for Solar Powered LED Lighting System in International

    Journal of Engineering and Technology (IJET) Volumeg No 1 Feb-Mar 2013.

    15.P. S. Revankar, W. Z. Gandhare and A. G. Thosar Government College of

    Engineering, Aurangabad, Maximum Power Point Tracking for PV Systems

    Using MATLAB/SIMULINK, 2010 Second International Conference on Machine

    Learning and Computing.

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