FAKULTI KEJURUTERAAN ELEKTRIK

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

FINAL YEAR PROJECT

FINAL REPORT

DEVELOPMENT OF SELF-POWERED DUAL-AXIS SOLAR TRACKING

SYSTEM

Chan Zhi Hao

Supervisor:

Zamani Md Sani

Bachelor of Mechatronic Engineering with Honours

May 2013

DEVELOPMENT OF SELF-POWERED DUAL-AXIS SOLAR TRACKING

SYSTEM

CHAN ZHI HAO

A report submitted in partial fulfillment of the requirements for the degree

of Bachelor of Mechatronic Engineering with Honours

Faculty of Electrical Engineering

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

2013

“ I hereby declare that I have read through this report entitle “ Development of Self-

powered Dual-axis Solar Tracking System ” and found that it has comply the partial

fulfillment for awarding the degree of Bachelor of Mechatronic Engineering with Honours ”

Signature : .......................................................

Supervisor’s Name : Zamani Md Sami

Date : .......................................................

To my beloved father and mother

I declare that this report entitle “ Development of Self-powered Dual-axis Solar Tracking

System ” is the result of my own research except as cited in the references. The report has

not been accepted for any degree and is not concurrently submitted in candidature of any

other degree.

Signature : ...........................................................

Name : CHAN ZHI HAO

Date : ...........................................................

i

ACKNOWLEDGEMENT

In completing this project, I have received a lot of helps from my supervisors,

lecturers, researchers and family members and fellow friends.

First, I want to give my upmost thanks to my supervisor, En Zamani Md Sani who

gave me an opportunity to do this project, for guiding and assisting me through the

completion of this project. Without his guidance and persistent help, this project would not

have been successful.

Next, I would like to express deepest appreciation to my parents in supporting me

mentally and financially, for their encouragements and supports.

It is also my duty to record my thankfulness to my fellow friends that gave advice

at some points and lent me a hand in completing the project. Also to a friend that offered

this private space for field test and analysis of the prototype.

Finally, I also take this opportunity, my sense of gratitude to one and all who,

directly or indirectly, have helped me in this project.

ii

ABSTRACT

Solar energy is the most readily available energy available on earth. The energy of the sun

is used since ancient times. With fast growing environmental concerns over the climate

change risks associated with power generation with non-renewable energy, solar power

has been the best answer over the decades. However, the output power of the solar cell

panel is highly affected by the sunlight incident angle. By tracking the solar panel to the

sun, it can always be pointing at the optimum angle to harvest the maximum solar energy

throughout a day or a year. In this project, a new method of solar tracking is presented.

The sun movements are studied to design the prototype of sensor and the solar tracker. By

using arrangement of six (6) Photodiode and one (1) solid cylinder, a prototype sun-

pointing sensor is designed. The sensor works by determining the location of solid

cylinder’s shade and tracker would track the sun position in opposite direction. The dual-

axis mechanism of the tracker would enable the system to track based on the sun azimuth

and altitude. Two DC motors with worm gear are used as actuators; first motor rotates at x-

axis (elevation) while second motor rotates at z-axis (azimuth). Also, a potentiometer is

also used to read the solar panel elevation position. The solar energy harvested is then

stored in a Lithium Polymer (Li-Po) battery. The method is discussed here for an

automatic operation of the system which includes an intelligent tracking method, self-

sufficient power supply; using microcontroller and active tracker. Moreover the prototype

is designed to suit smaller system which is suitable for small domestic or household home-

grown solar power plant; where it is affordable, automatous, required minimum

maintenance and endplay. After the system is built, various experiments are done to test

the functionality and sustainability of the tracker. The performance of the active solar

tracker is also compared to the fixed solar panel to determine the improvement in solar

energy harvesting capability. The tracker is able to follow the movement of sun throughout

the day; while power is stored in the battery. There is also increase in efficiency of 28%

when compared to fixed panel.

iii

ABSTRAK

Tenaga suria merupakan tenaga yang paling sedia ada di bumi kita. Tenaga matahari

digunakan sejak zaman purba. Dengan perkembangan yang pesat, alam sekitar

menghadapi risiko termasuk perubahan iklim. Penjanaan kuasa boleh diperbaharui

menjadi isu hangat. Tenaga solar telah menjadi jawapan yang terbaik bagi kuasa boleh

diperbaharui sejak beberapa dekad dahulu. Walau bagaimanapun, kuasa keluaran sel papan

solar adalah dipengaruhi oleh sudut tuju cahaya matahari. Dengan menjejaki papan solar

terhadap matahari, ia akan sentiasa menunjuk pada sudut yang optimum untuk

memperoleh tenaga solar yang maksimum sepanjang hari atau setahun. Dalam projek ini,

satu kaedah baru alat pengesanan solar telah dibentangkan. Pergerakan matahari dikaji

sebelum mereka-bentuk prototaip alat pengesanan dan papan solar bergerak tersebut.

Dengan menggunakan susunan enam (6) fotodiod dan satu (1) silinder, prototaip alat

pengesan menunjuk matahari direka. Alat pengesan tersebut berfungsi dengan menentukan

lokasi bayang-bayang silinder supaya dapat mengesan kedudukan matahari dalam arah

bertentangan. Mekanisme dwi-paksi penggerak itu akan membolehkan sistem untuk

bergerak berdasarkan elevation dan azimuth matahari. Dua DC motor dengan wrom gear

digunakan sebagai penggerak; motor pertama berputar pada paksi-x (elevation) manakala

kedua motor berputar pada paksi-z (azimut). Selain itu, potensiometer juga digunakan

untuk membaca kedudukan elevation papan solar. Tenaga solar yang diperoleh kemudian

disimpan di dalam bateri Lithium Polymer (Li-Po). Kaedah projek ini dibincangkan di sini

adalah operasi automatik yang merangkumi kaedah pengesanan, bekalan kuasa sendiri,

pengawal pintar, mikropengawal dan penggerak aktif. Selain itu prototaip itu direka untuk

disesuaikan dengan sistem yang lebih kecil yang sesuai untuk rumah dan loji jana kuasa

kecil untuk isi rumah; di mana ia adalah berharga berpatutan, automatik, dan memerlukan

kadar penyelenggaraan yang minimum. Selepas sistem ini dibina, pelbagai eksperimen

dilakukan untuk menguji fungsi dan kemapanan projek ini. Prestasi penggerak solar aktif

juga dibandingkan kepada papan solar tidak bergerak untuk menentukan peningkatan

dalam keupayaan memperoleh tenaga solar. Kesimpulannya, papan solar bergerak itu

dapat mengikuti pergerakan matahari sepanjang hari, sedangkan kuasanya disimpan di

dalam bateri. Peningkatan dalam kecekapan sebanyak 29% juga dapat dilihat jika

dibandingkan dengan papan solar tidak bergerak.

iv

TABLE OF CONTENTS

CHAPTER TITLE PAGE

ACKNOWLEDGEMENT i

ABSTRACT ii

ABSTRAK iii

TABLE OF CONTENTS iv

LIST OF TABLES viii

LIST OF FIGURES ix

LIST OF ABBREVIATIONS xii

LIST OF APPENDICES xiii

1 INTRODUCTION 1

1.1 Significant of Study 2

1.2 Motivation 2

1.3 Problem Statement 3

1.4 Objective 4

1.5 Scope 4

2 LITERATURE REVIEW AND PROJECT BACKGROUND 5

2.1 Solar Panel Basics 5

2.2 Solar Panel Angle and Some Astrology 6

2.3 Fixed Solar Panel Efficiency Review 8

2.4 Solar Energy Gain with Solar Tracking 10

v

CHAPTER TITLE PAGE

2.5 Tracking System for Automatic solar tracker 11

2.5.1 Mechanical Tracker 11

2.5.2 Electronic Tracker 12

2.5.3 Time and Date Based Tracker 14

2.6 Summary of Literature Review 14

3 METHODOLOGY 17

3.1 Introduction and Overview of the Project 17

3.2 The Four Subsystems 18

3.2.1 Subsystem 1: Actuator 18

3.2.1.1 Dual Axis Solar Tracker Design 18

3.2.1.2 DC Motor Torque Calculation 19

3.2.1.3 The Base and Supporting Link 22

3.2.2 Subsystem 2: Sensors 24

3.2.2.1 Sun Pointing Sensor Prototype Design 24

3.2.2.2 Solar Panel Elevation Position Reading 26

3.2.3 Subsystem 3: Control Electronics 28

3.2.3.1 Microcontroller and H-Bridge 28

3.2.3.2 Microcontroller Program 30

3.2.3.3 Program Flow Chart 31

vi

CHAPTER TITLE PAGE

3.2.4 Subsystem 4: Power supply 34

3.2.4.1 Battery 35

3.2.4.2 Battery Charger and Boost Converter 35

3.2.4.3 Solar Panel 36

3.2.4.4 Power Saving 37

3.3 Project Experiments and Tests 38

3.3.1 Test for the developed sun pointing sensor of Photodiodes. 38

3.3.2 Experiment for Dual Axis tracking ability with developed sun pointing sensor. 39

3.3.3 Power usage test 39

3.3.4 Full system field test 40

4 RESULTS AND DISCUSSIONS 41

4.1 Chapter Overview 41

4.2 Full Electrical Circuit 41

4.3 Sun Pointing Sensor 42

4.4 Overall Design of the Solar Tracker 43

vii

CHAPTER TITLE PAGE

4.5 Tests and Experiments Results and Discussions 43

4.5.1 Test for the developed sun pointing sensor of Photodiode. 43

4.5.1.1 Results and Analysis 43

4.5.1.2 Discussion 44

4.5.2 Experiment for Dual Axis tracking ability with developed sun pointing sensor. 46

4.5.2.1 Results and Analysis 46

4.5.2.2 Discussions 47

4.5.3 Power Usage Test Result and Discussions 49

4.5.4 Full System Field test 50

4.5.4.1 Results and Analysis 50

4.5.4.2 Discussions 54

5 CONCLUSION AND RECOMMENDATION 56

5.1 Chapter Overview 56

5.2 Conclusion 56

5.3 Recommendations 57

REFERENCE 58

APPENDIXES 60

viii

LIST OF TABLES

TABLE TITLE PAGE

2.1 Important Solar Angles 8

2.2 Major difference between Fixed Solar Panel with Solar Panel with Tracking 14

2.3 Evaluation chart of each electric actuators for the project 15

2.4 Evaluation chart of each electronic sensors for the project 16

2.5 Summary of previously developed Solar Tracking System 16

3.1 The output voltage and A2D step size at each positions 27

3.2 Pin voltage readings of Photodiode under various conditions 38

3.3 Solar energy gain comparison between Fixed and Tracking Solar panel 40

4.1 Pin Voltage readings of Photodiodes in various lighting conditions for photodiode covered by shadow and under light 44

4.2 Observation of the panel movement according to the dark area 47

4.3 Current Draw of the full system at each stages 49

4.4 The open-circuit voltage, short-circuit current and output power of fixed and tracking solar panel 52

4.5 Average value for open-circuit voltage, short-circuit current and output power of fixed and tracking solar panel 54

ix

LIST OF FIGURES

FIGURE TITLE PAGE

1.1 The World Solar Energy Map 3

1.2 (a) The sunlight is diffused away from the panel 4

1.2 (b) The sun light stay more focus 4

2.1 The p-SI and n-Si node in PV cells produced by doping 6

2.2 Angle of the position of the sun in on the equinox at latitude 30° 7

2.3 Solar angles used for PV panels 7

2.4 Output current of a solar cell 9

2.5 A passive solar tracker using two identical cylindrical tubes 12

2.6 (a) sun-pointing sensors, 13

2.6 (b) tilted mount of photo sensors, 13

2.6 (c) precise sun pointing by means of a collimator 13

3.1 The 4 subsystems of the project 17

3.2 Overview of the project 18

3.3 (a) The 2 axis mechanism used in this project 19

3.3 (b) This mechanism that should be avoided 19

3.4 The worm with worm wheel 21

3.5 (a) The cross section of the dc motor with gear set 21

3.5 (b) The assembled dc motor 21

3.5 (c) The clutch and clutch gear 21

3.5 (d) Assembly for 5402:1 gear ratio 21

3.6 (a) Motor 1 is placed close to the panel, small r, less torque required 22

3.6 (b) Motor 1 is placed futher to the panel, large r, more torque required 22

x

FIGURE TITLE PAGE

3.7 First design during development stage 23

3.8 Final deisgn of the solar tracker 23

3.9 The sundial used during the old days to tell the time 24

3.10 (a) Sketch up of the designed sun pointing sensor 25

3.10 (b) Shadow casted at one of the photodiodes 25

3.11 (a) Photodiode with an adjustable pull down resistor 25

3.11 (b) Schematics to show clear view of the circuit 25

3.12 Potentiometer placed at the bottom of the panel to read the elevation 26

3.13 Turning the potentiometer, “left” and “right” resistance to varies 26

3.14 The three positions of elevation 27

3.15 The PIC 16F877A from Microchip 28

3.16 2 pins 1.8432MHz XT Crystal Oscillator used in this project 29

3.17 L293B Dual Channel H-Bridge 29

3.18 Control system block diagram 30

3.19 The program main flow chat. 32

3.20 Single Cell 3300mAh Li-Po Battery 35

3.21 Sparkfun LiPo Charger/Booster PRT11231 36

3.22 6V 0.84A Solar Panel 36

3.23 Reconnecting electrical connections 37

3.24 A few position of light source is shined towards the sensor 39

4.1 Project Full Circuit 41

4.2 Inside the electrical box 42

xi

FIGURE TITLE PAGE

4.3 (Left) Design using LDR, (Right) Final design using photodiode 42

4.4 (a) The preliminary design 43

4.4 (b) the final design of the overall prototype 43

4.5 Shows value higher than 150000 Lux under direct sunlight 44

4.6 Resistance against Light Intensity for LDR 45

4.7 Top view of the sensor 46

4.8 (a) The solar tracker movement for Motor 1 and Motor 2 46

4.8 (b) Photos of the solar tracker movements 47

4.9 Light source from A to B what will cast shadow to either 1 or 2 48

4.10 (a) Solar panel position before minute changes 48

4.10 (b) Solar panel position after minute movements 48

4.11 Before and after elevation reading for minute changes 49

4.12 The setup of the field test on top of a roof 50

4.13 Comparison of the panel direction the morning and evening 51

4.14 Open circuit Voltage against Time 53

4.15 Short Circuit Current against Time 53

4.16 Output Power against Time 54

xii

LIST OF ABBREVIATIONS

Si – Silicon

RMSD – Root-mean-square deviation

NASA – National Aeronautics and Space Administration

LDR – Light Dependent Resistor

PLC – Programmable Logic Controller

PV – Photovoltaic

DC – Direct Current

A2D – Analogue to Digital

PWM – Pulse Width Modulation

Li-Po – Lithium Polymer

LP – Low Power

XT – X-tal

HS – High Speed

WDT – Watch Dog Timer

LED – Light Emitting Diode

xiii

LIST OF APPENDICES

APPENDIX TITLE PAGE

A Microchip PIC 16F87XA Microcontroller 60

B Four Channel H-Bridge L293B 61

C Microchip MCP73831 Single Cell Management Controllers 62

D Texas Instruments TPS61200 Voltage Boost Converter 63

E Power Cell - LiPo Charger/Booster PRT-11231 64

F OSRAM SFH203 P Photodiode 65

G TAMIYA 700110 Crank Axle Gearbox 66

H Mabuchi FA-130 DC Motor 67

I PIC16F977A MikroC Source Code (parts) 68

J TURNITIN Report 70

1

CHAPTER 1

INTRODUCTION

This chapter presents the significant of study, motivation, problem statement,

project objective and scope of the project.

Since ancient time, solar energy has been used and harvested for the benefits of

well-being of humans; by using the radiant light and heat of solar energy, human used the

sun to dry things and to cook foods. Nowadays, the way human harvest the energy source

from the sun has greatly improved. Various solar energy technologies such as heating

directly from the sun, photovoltaic solar cells, solar architecture, thermal electricity,

artificial photosynthesis and others can make contribution to improve humans‟ energy

security.

As human awareness towards greener environment increases, human also shift

from using non-renewable source of energy or fossil fuels towards renewable energy such

as solar, wind and hydro energy. The clean, inexhaustible and affordable solar power is

definitely the way to go for long term benefits.

2

1.1 Significance of Study

This study will be a significant endeavour in improving the efficiency of solar

panel for electricity generation. It also includes the study of solar altitude of the sun and

the mechanism for tracking system of the solar panel holder. By tracking the sun position

and moving the solar panel to the direction of the sun, the solar panel holder is assured to

be able to harvest the maximum solar energy throughout the day. This research will also

provide recommendations on how to improve the tracking sensor for higher precision

tracking. Moreover, the tracking system is to be kept at an affordable price so that

individuals and household can use this method. Besides, people in underprivileged

countries could benefit from the use of a solar electricity generation system. Consequently,

this approach would greatly cut the electricity bill, provide basic needs for the

underprivileged, decrease carbon footprint of each individuals and delay global warming

crisis.

1.2 Motivation

With petrol piece increasing exponentially which lead to increases of electric bills,

at no other time in our history have renewable sources of energy been more critical - for

our economy, for our self-preservation, for our planet. Alternative source of energy is

needed to cut down our daily expenses and to save our earth. One of the alternative

renewable energy that is widely used is the solar power.

1.75x1017 Joules is the number of energy earth receives from the sun for each

seconds. Studies show that by covering 1% of the land on earth with photovoltaic cells,

human can obtain enough electricity to satiate the world‟s energy consumption until year

2050.

Solar energy can be obtained all over the globe and require little space, hence

suitable for private residential power plant. Also, Malaysia is located at the earth equator

which is blessed with good amount of sun light throughout the year. Malaysia receives

average of 11 hours of day light every day, which makes this place very suitable for solar

energy harvesting. Furthermore, as shown in Figure 1.1, the solar energy distributed

3

around the earth shows that there are many countries that are suitable to choose solar

energy as the source of electricity.

Figure 1.1: The World Solar Energy Map, shows solar distribution throughout a year [1].

The reason solar energy is preferred because it does not pollute the air when being

converted into electricity. Solar energy systems would significantly contribute to reduction

in greenhouse gas emissions and therefore reduce the impact of global warming and

provide a better environment for future generations.

1.3 Problem Statement

One of the biggest issues with traditional fixed static solar panels is reflection.

Traditional static solar panel is unable to harvest the maximum solar energy of the sun

because of different position in azimuth and elevation of the sun. Referring to Figure 1.2, a

lot of sunlight is either reflected or diffused away when the panel is in shallow angle. The

problem worsens when there are clouds or hazes that reduce the intensity of light. This

cause fixed solar panel to only harvest the maximum energy at a specific time of a day or a

year, as the position of the sun in the sky moves during the day (and during the year), there

are often lengthy periods when static panels cannot optimally collect sunlight especially at

non-tropical countries. Efficiency of the solar panel would be optimal when the light hits

the panel at a steep 90 degree. Solar tracking is one of the most straightforward methods to

improve the performance and economics of a solar installation. An active 2-axis solar

tracking panel holder and a sensor for tracking the sun position has to be designed to

effectively increase the efficiency of harvesting the solar energy. The solar panel holders

should operate with the goal of minimizing the angle of incidence between the ray of

incoming sunlight and the solar panel.

4

Figure 1.2: (a) The sunlight is diffused away from the panel because of the angle between

the panel and direction of lights. (b) The sun light stays more focus to the solar panel as

there is no angle difference.

1.4 Objective

The objectives of this project are:

1. To study the azimuth, elevation and altitude of the sun.

2. To develop a prototype tracking sensor, sending signal to the solar panel holder

3. To develop a mechanism for the actuator of the panel with 2 degree of freedom.

4. To compare the efficiency of the solar tracking panel to the static fixed panel.

1.5 Scope

The scope of this project is:

1. Development of a new type of sensory system that is able to track the sun correctly.

2. Development of a prototype solar panel holder with two-axis actuator mechanism

at elevation and azimuth.

3. The solar tracker should enable the solar panel to improve harvest yield of solar

energy.

4. The system should be self-sufficient by charging a battery and supply to load at the

same time.

5

CHAPTER 2

LITERATURE REVIEW AND PROJECT BACKGROUND

To complete this project, many sources have been reviewed, which include journals,

articles, books and internet. These sources served as the ideas and thoughts that lead to the

success of this project.

2.1 Solar Panel Basics

A solar panel is a connected assembly of solar cells which also known as

photovoltaic (PV) cells. Solar panels can be used to generate and supply electricity in

commercial and residential applications by converting sun light to electricity.

Photovoltaic cells use light energy (photons) from the sun to generate electricity.

Wafer-based crystalline silicon cells or thin-film cells based on cadmium telluride or

silicon are used to make these PV cells. PV cells have one or more electric field that acts to

force electrons freed by light absorption to flow in a certain direction. Electrical

connections are made to achieve a desired output voltage and current by connecting them

in series and/or parallel. The cells must also be protected from the surrounding such as

scratches and moisture [2].

Doping for common semiconductor (normally silicon for PV) involves adding

atoms with different number of electrons to create unbalanced number of electrons in the

base material. As in Figure 2.1, in each photovoltaic cell, a p-n junction is created in

silicon by the doping process. When the cells are exposed to photons, electrons will flow

from n-junction to the p-junction which allows electric current to flow.

Another interesting fact is when these PV cells are made into miniature size; it

became photodiode that can be used as sensor. When large cells are made, they are

arranged in series and parallel to form what is normally seen, the solar panel.

6

Figure 2.1: The p-SI and n-Si node in PV cells produced by doping, they cause electron to

move when photons strike the surface; hence, cause current to flow [2].

Recently, some solar panel designs also include concentrators in which light is

focused by lenses or mirrors onto an array of smaller cells. Also, Solar tracking also

improve the solar panel to harvest the maximum light throughout a day and a year.

There are many reasons solar panels are chosen as a more preferable good

alternative for electricity generation. No fuel is needed for solar energy generation; hence,

does not release polluting substance. Besides, there are no or least moving parts to wear

out (eg. compared to hydroelectric generation). Also, solar panels are quick responding,

adaptable for on-site installation and easy maintenance. Furthermore, with the introduction

of Feed in Tariff (FiT), solar power can be integrated with other renewable energy sources

and the grid. Last, they are simple and efficient.

2.2 Solar Panel Angle and Some Astrology

On one day every year when the sun is positioned directly above our planet's

equator, it is equinox. It is when the angle between a line that points to the sun and a line

that points vertically matches the latitude of a position. In the equator, equinox happens

when the sun is directly perpendicular to the equator while at the latitude of 30°, then on

the equinox the sun will be 30° to the south from the vertical (see Figure 2.2). The sun's

position on the equinox is the average location of the sun throughout the year and is a great

reference to use when designing a solar system for a specific location.