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DESIGN OF MICRO-POWER GENERATOR BASED ON
ELECTROMAGNETIC MECHANISM HARVESTING ENERGY FROM
DIRECT AIR FLOW
TAN JYE GIN
A thesis submitted
in fulfillment of the requirements for the Bachelor Degree Of Electronic
Engineering (Industrial Electronic)
Faculty of Electronic Engineering and Computer Engineering
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
JUNE 2013
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“I declare that this thesis entitle “DESIGN OF MICRO-POWER GENERATOR
BASED ON ELECTROMAGNETIC MECHANISM HARVESTING ENERGY
FROM DIRECT AIR FLOW” is the result of my own reaesrch except as cited in the
references. The thesis has not been accepted for any degree and is not concurrently
submitted in candidature of any other degree.”
Signature : ...........................................
Name : TAN JYE GIN
Date : ............................................
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“I declare that I have read this work and in my opinion this work is adequate in terms
of scope and quality foe the purpose of awarding a Bachelor’s Degree of Electronic
Engineering (Industrial Electronics).”
Signature : ...........................................
Name : DR. KOK SWEE LEONG
Date : ............................................
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To my beloved family and friends who, of all that walk the earch, are most precious
to me.
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ACKNOWLEGEMENT
In preparing this thesis, I was in contact with many people, researchers,
academicians and practitioners. They have contributed towards my understanding and
thought. In particular, I wish to express my sincere appreciation to my thesis
supervisor, Dr. Kok Swee Leong, for encouragement, guidance critics and friendship.
Without his continued support and interest, this thesis would not have been same as
presented here.
I am also indebted to University Techinical Malaysia Malacca (UTeM) in
allowing me to use entire facilities available to complete my testing and studies.
My fellow friends should also be recognised for their support. My sincere
appreciation also extends to others who have provided assistance at various occasions.
Their views and tips are useful indeed. Unfortunately, it is not possible to list all of
them in this limited space. I am grateful to all my family members.
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ABSTRACT
This project is to construct a micro-power generator based on electromagnetic
mechanism harvesting energy from direct air flow. The concept is to make a
magnet-attached cantilever to oscillate in the presence of direct air flow. The
oscillation happens when air travel and provide a force to push the cantilever
downward in a repetition manner as a result of vortex generated underneath the
cantilever. In order to generate electrical energy, a pair of magnet mounted on the
cantilever and with a magnetic coil in between and fixed vertically at the tip of the
cantilever is used to pick up the induced current. The E.M.F. voltage produced is
directly proportional to the rate of change of magnetic flux. Experiment is carried out
to analyze the output voltage produced by the micro-generator. The output power
generated is able to activate small electronic device, this is shown by an LED
indicator. A prototype for the micro power generator is constructed to demonstrate
the capability of the generator in producing a sufficient electrical power by
transforming kinetic energy to electrical energy. The direct air-flow is eco-friendly,
less cost and renewable.
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ABSTRAK
Projek ini dijalankan bertujuan untuk menjana kuasa mikro dengan kehadiran
aliran udara terus berdasarkan teori elektro-magnet. Penjanaan juasa dibinakan
melalui satu julur yang berayun tegak dengan kemasukan aliran angin terus.
Perayunan tersebut berlaku apabila penekanan julur secara berualang-ulang daripada
pengaliran angin terus akibat vorteks yang terdapat di bawah julur tersebut. Susunan
sepasang magnet dibina pada julur bersama gegelung magnet yang diletakkan di
tengah serta berdiri tegak di hujung julur adalah untuk menghasilkan tenaga elektrik.
Penghasilan voltan E.M.F. adalah berkadar langsung dengan kadar perubahan fluks
magnet. Eksperimen telah dilaksanakan untuk menganalisis penghasilan voltan
daripada penjana mikro ini. Kuasa hasilan daripada penjana mikro ini dapat
mengaktifkan alat elektronik yang memerlukan kuasa kecil seperti yang ditunjukkan
oleh isyarat LED. Satu prototaip penjana mikro kuasa ini dibinakan untuk
mengetengahkan keupayaan penjana ini menukarkan tenaga kinetik kepada tenaga
elektrik dengan bersumberkan aliran udara terus. Aliran udara terus merupakan satu
sumber yang mesra alam, kos rendah dan boleh diperbaharui.
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TABLE OF CONTENT
PAGE
Title page i
Declaration iii
Dedication v
Acknowledgement vi
Abstract vii
Abstrak viii
Table of content ix
List of Tables xi
List of Figures xii
1. INTRODUCTION
1.1 General Background 1
1.2 Project Overview 3
1.3 Problem Statement 3
1.4 Objectives 5
1.5 Scope of work 5
1.6 Report Structure 6
2. LITERATURE REVIEW
2.1 Introduction 7
2.1.1 Ambient Energy Souces 8
2.1.2 Ambient Energy System 9
2.1.3 Comparison of Power Density of Energy Harvesting Methods 11
2.1.4 VibrationEnergy-Harvesting Techiques 12
2.2 Basic Principles of Electromagnetic Energy-Harvesting 12
2.2.1 Working Principles 12
2.2.2 Faraday’s Law 14
2.2.3 Voltage Multipliers 14
2.3 Previous research related to current study
15
3. METHODOLOGY
3.1 Experimental Flow Chart 22
3.2 Simulation Software 24
3.2.1 Multisim Software 24
3.2.2 Proteus Software 25
3.3 Hardware Protype 26
4. RESULT AND DISCUSSIONS
4.1 Theoretical Hypothesis 30
4.2 Number of Turns of Coil 31
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4.2.1 Experimental Result 31
4.3 Stages of Multipliers 32
4.3.1 Simulation Result 33
4.3.2 Experimental Result 41
4.4 Discussion of Result 46
4.4.1 Stages of Multipliers 46
4.4.2 Comparision of Design 49
4.5 Fabrication Citcuit
51
5. CONCLUSION & SUGGESTION
5.1 Conclusion 53
5.2 Suggestion for Future Development 54
REFERENCES 56
APPENDIX 59
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LIST OF TABLES
TABLE TITLE
PAGE
2.1 Ambient Energy Sources 9
2.2 Comparison Power Density of Energy Harvesting Methods 11
2.3 Comparison of Vibration Energy-Harvesting Techniques 12
2.4 Comparison of electromagnetic vibration transducer prototypes 16
3.1 Common magnetic material properties 27
3.2 Specification of Energy Harvester 29
4.1 Result of Output Voltage 32
4.2 Simulation Output Voltage for Input Voltage = 0.1V 34
4.3 Result of Simulation Power for Input Voltage = 0.1V 37
4.4 Simulation Output Voltage for Input Voltage = 0.5V 39
4.5 Result of Simulation Power for Input Voltage = 0.5V 40
4.6 Experimental Output Voltage for Input Voltage=0.1V 42
4.7 Result of Experimental Power for Input Voltage = 0.1V 43
4.8 Experimental Output Voltage for Input Voltage=0.5V 44
4.9 Result of Experimental Power for Input Voltage = 0.5V 45
4.10 Comparison of Results for Input=0.5V 47
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LIST OF FIGURES
FIGURE TITLE
PAGE
1.1 Power consumption of various wireless standards 2
1.2 Projected Annual Battery Change Labor Cost 4
2.1 Scavengable Energies from Non-Biological Converted To
Electrical Energy for Use by Small Electric Unmanned Systems
8
2.2 Ambient Energy Systems 10
2.3 Comparisons of Battery and Energy Harvesting 10
2.4 Karman vortex street 13
2.5
2.6 Cantilever-Based Electromagnetic Micro-Generator 17
2.7 Relative Displacement in Electromagnetic Micro-Generator 17
2.8 Energy Harvester from Airflow 18
2.9 Principles Of Energy Harvester 19
2.10 Principles of Airflow Energy Harvester 20
2.11 Output Power of Airflow Energy Harvester 21
3.1 Project Flow Chart 23
3.2 Constructed Energy Harvester 26
3.3 Fabricated Tunnel 27
3.4 Turning Fan 27
3.5 Different numbers of turns of coil 28
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3.6 Acrylic 28
4.1 Graph of Mean Output Voltage vs Number of Turns of Coil 32
4.2 Designed Circuit 33
4.3 Simulation of Input and Output Waveform for Input Voltage
= 0.1V
33
4.4 Result of Measuring Voltage for Input Voltage = 0.1V 34
4.5 Comparison of Theoretical Capacity and Energy Stored 35
4.6 Simulation Power Generated for Input Voltage = 0.1V 37
4.7 Simulation of Input and Output Waveform for Input
Voltage=0.5V
38
4.8 Result of Measuring Voltage for Input Voltage = 0.5V 38
4.9 Comparison of Theoretical Capacity and Energy Stored 39
4.10 Simulation Power Generated for Input Voltage = 0.5V 40
4.11 Experimental circuit 41
4.12 Comparison of Theoretical Capacity and Energy Stored 42
4.13 Experimental Power Generated for Input Voltage = 0.1V 43
4.14 Comparison of Theoretical Capacity and Energy Stored 44
4.15 Experimental Power Generated for Input Voltage = 0.5V 45
4.16 Comparison of Voltage Output 48
4.17 Experimental Results with Standard Deviation 48
4.18 LTC 3535 in DFN Package 49
4.19 Circuit Layout of LTC 3535 50
4.20 Performance of LTC 3535 50
4.21 Snapshots from Proteus 51
4.22 Snapshots from ARES 51
4.23 Successful Fabricated Circuit (Front) 52
4.24 Successful Fabricated Circuit (Back) 52
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CHAPTER 1
INTRODUCTION
In this chapter, the discussion is mainly about the introduction and motivation
of this project. The investigation is included the background of project, project
overview, problem statement that inspired, objectives to carry out and the scope for
the project. The overall report structure is concluded at the end of this chapter.
1.1 General Background
Energy has become an essential element in human life which integrals with
the almost every civilian application in the developing modern societies such as
domestic, transport, industrial, medical, etc. Hence, there is a need for a secure and
accessible supply of energy for sustainability of the growing world population. The
term of “renewable energy” has been defined as the only solution to the growing
energy challenge [11]. Renewable energy is believed comes from the sources that are
easily replenished, likewise solar, wind, geothermal, wave, and tidal power [2].
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The argument of environmental damage from wind energy has been debated.
The wind energy system impacts on noise pollution and visual pollution. The
large-scale wind generation systems are built in more remote area and create noise
pollution which harshly harmful to native animal species as well as the nearby
residents. Visual pollution changes the image of the landscape. Climatological
impacts from wind generation system are also come across discussion. In the early
stage of implementation, avian mortality was an issue. The birds flying in close
proximity were likely to be dragged into the flow and killed [8].
Energy harvesting technologies are ideas of alternative energies by converting
non-electric environmental ambient energy into electrical energy. Obtaining an
energy autonomous and maintenance-free sensor system with long-availability life
time is the priority achievement [9]. Figure 1.1 shows the power acquired by special
purpose low-data rate network protocols such as Zigbee for transmission [6].
Figure 1.1: Power consumption of various wireless standards [6]
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1.2 Project Overview
Ambient energy harvester is known as power scavenging method. In this
context, airflow is presented naturally and regarded as an environment-friendly
power source.
The airflow energy harvester is proposed to have a geometry made of a wing
that attached to a cantilever spring, permanent magnet, coil, ferromagnetic circuit
with air gap and a conversation circuitry.
Alternating current (AC) is induced in a conductive coil when magnetic flux
changes. This can be done by either moving the coil or the permanent magnet. In this
project, air flow is used as the ambient source to oscillate a magnet which is attached
to a cantilever. When the direct airflow is entering the energy harvester, it is blocked
by the bluff body constructed. A vortex is circulated under the cantilever. Current is
generated when the cantilever moving along with the magnetic and cut the magnetic
flux through the moving coil. Power is harvested from this system is capable to
power up some small electronic devices such as wireless sensor node.
1.3 Problem Statement
A battery which is also known as a DC voltage source has finite amount of
current over time. The battery cannot supply a fixed amount of current at a constant
voltage indefinitely for any length of time. As the battery ages and becomes
discharged, its capacity to generate current is diminishing as the time goes by. Since
some of the batteries are not rechargeable, it may cause hazard to the users. The
leakage of chemical from the battery after long-used is also will lead to the
hazardous of environment and health [4].
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Thus, energy storage technologies have been greatly developed in the recent
past. However, the progress has not been mature to keep up with microprocessors,
memory storage, and wireless technology applications. The battery life time is
limited which unable to last for a longer period of time. Figure 1.2 illustrates the
annual battery change labor cost[5]. Maintenance of a large-scale network is difficult
to carry out for hundreds or thousands of sensor nodes [14].
Figure 1.2: Projected Annual Battery Change Labor Cost [5]
According to Zhu [16], the smart buildings in technology-driven generation
are equipped with intelligent systems which acquired numerous sensors. Wired
sensors have some drawbacks on high wiring and maintenance costs and time
consuming. Hence, wireless self-powered sensors are desirable in applications of
systems. However, batteries as a conventional power supply have a finite amount of
energy, difficulties to deploy in large scale or inaccessible locations and required
high maintenance. Furthermore, the operating temperature of batteries which is
ranging from -55℃ to +85℃ is insufficient to apply in some application [9].
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1.4 Objectives
Three specific objectives have been defined for this study;
1. To design an energy harvester based on electromagnetic mechanism
harvesting ambient energy from airflow.
2. To construct a prototype of the energy harvester using available
materials.
3. To analysis the workability of the air flow energy harvester on a daily
application.
1.5 Scope of the Project
Scope is designed so that the project is within the area of concern. The scopes
of the project are as follows:
1. The experiment is conducted in a fabricated tunnel which has length of
1-2metres and height of ≈25cm.
2. Size of energy harvester is small (12cm x 8cm x 6cm).
3. The airflow source is within closed environment.
4. The power harvested is in the range of mW and the voltage induced is
lesser than 2V.
5. The mechanical design of the cantilever is referred.
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1.6 Report Structure
In this report, there are three chapters are written. Each chapter has dedicated
different focus and discussions.
As in Chapter One, the project is introduced. Brief general background,
inspired problem statement, objectives, limits of the report is outlined.
Literature review is the main concern in Chapter Two. The literature review
evaluates the previous research that has been proposed. The review is described and
summarized.
Chapter Three is reporting on the methodology. The purpose of this chapter is
to explain and document the research approaches and testing strategy carried out in
the project.
Chapter Four is discussing the results and observations obtained .throughout
the research. Analysis on the output is presented for theoretical, simulation and
experimental findings.
In Chapter Five, the overall summary of the research based on the objectives
and achievements will be performed.
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CHAPTER 2
LITERATURE REVIEW
In this chapter, existing knowledge is outlined. The relevant information on
previous technologies is identified and justified.
2.1 Introduction
Energy harvesters have been discussed intensely for the potential to be
applied in wireless sensor node applications. The term of ambient energy harvesting
is applied. The harvested power is dependable on the energy source being harvested.
A survey has proved that the greatest effectiveness can be obtained by devices within
the range of 10-100 Hz [7]
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2.1.1 Ambient Energy Sources
Several of scavenging energy sources is categorized into five majors which
are photonic, kinetic, thermal, electromagnetic, autophagous (self-consuming)
structure-power. A suggestion [10] of scavengable energies from non-biological is
illustrated in Figure 2.1.
Figure 2.1: Scavengable Energies from Non-Biological Converted To Electrical
Energy for Use by Small Electric Unmanned Systems
Whereas Yildiz [14] claimed that no single power source is enough for all
applications and the energy source must be selected by considering the application
characteristics. Hence, the ambient energy sources are summarized with their
characteristics in Table 2.1 below.
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Table 2.1: Ambient Energy Sources
Energy Sources Characteristics
Human Body Mechanical and thermal energy is generated by human or
animal body by actions.
Natural Energy Wind, water flow, ocean waves, and solar energy are
limitless readily available from environment.
Mechanical Energy
Ambient mechanical energy sources are captured from
vibrations of machines, mechanical stress, strains of
high-pressure motors, manufacturing machines, and waste
rotations.
Thermal Energy Waster heat energy from furnaces, heaters, and friction
sources.
Light Energy
The energy is captured through photo sensors, photo
diodes, and solar photovoltaic (PV) panels regardless from
indoor or outdoor.
Electromagnetic
Energy
Inductors, coils, and transformers are the considered
ambient energy sources dependable on application
requirement.
2.1.2 Ambient Energy Systems
A general overview of ambient energy-harvesting systems is illustrated as
Figure 2.2 [14]. In Figure 2.2, there are three rows of division. The first row indicates
the energy sources; the second row shows the actual implementation and employed
tools and the third row illustrates the techniques of energy-harvesting from each
source.
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Figure 2.2: Ambient Energy Systems
Energy harvesting has different charging rate across time and physical
domains. The energy harvesting has shorter duty cycle and the average charging rate
is lower than the rate of energy consumption. Figure 2.3 shows the comparison of
battery and energy harvesting.
Figure 2.3: Comparisons of Battery and Energy Harvesting
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2.1.3 Comparison of Power Density of Energy Harvesting Methods
Kazmierski [3] reported that power densities acquired from machine vibration
application and human-powered application are 800μW/cm3 and 140μW/cm3
respectively. The power output for vibration-harvesting inertial generators is highly
stimulated by frequency and amplitude of the vibration source.
In the study of Yildiz [14], the comparison of power density of energy
harvesting methods is highlighted in Table 2.2. The values are summarized from
published studies, experiments conducted and the information captured by reading
materials. From the Table 2.2, a wide range of potential scavenging energy from
various ambient energy sources is provided.
Table 2.2: Comparison Power Density of Energy Harvesting Methods
Energy Source Power Density & Performance
Acoustic noise 0.003μW/cm3 @ 75Db
0.96μW/cm3 @ 100Db
Ambient light 100mW/cm2 (direct sun)
100μW/cm2 (illuminated office)
Vibration (micro-generator) 4μW/cm3 (human motion-Hz)
800μW/cm3 (machines-Hz)
Vibrations (Piezoelectric) 200μW/cm3
Airflow 1μW/cm2
Temperature variation 10μW/cm3
Ambient radio frequency 1μW/cm2
