Multiple Wireless Power Transfer System.
MULTIPLE WIRELESS POWER TRANSFER SYSTEM
SAIDAH BINTI MUHTAR LUBIS
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
i
MULTIPLE WIRELESS POWER TRANSFER SYSTEM
SAIDAH BINTI MUHTAR LUBIS
This Report is Submitted in Partial Fulfillment of the Requirement for the Bachelor
Degree in Electronic Engineering (Wireless Communication) With Honours
Fakulti Kejuruteraan Elektronik dan Kejuruteraan Komputer
Universiti Teknikal Malaysia Melaka
June 2015
ii
iii
iv
v
DEDICATION
Dedicated to my beloved supervisor, lecturer, my family and all my friends.
vi
ACKNOWLEDGEMENT
I am grateful to ALLAH S.W.T for the good health and wellbeing that were
necessary to complete this thesis report. Alharndulillah, all Praise to thank to Allah
S.W.T the Almighty for giving me the Rahmah to finish my project successfully. I
would like to take this golden opportunity to express my appreciation and heartfelt
gratitude to my supervisor, Eng. Noor Badariah Binti Asan for the opportunity given
to me to do this project and for his belief. I really appreciate her guidance from the
initial to the final level that enabled me to develop an understanding of this research
thoroughly. Thank you very much for her endless support and ideas, during which she
has been patiently supervising my progress and encouraged me to do this project in the
right way. With full of hope, Allah SWT bless Her and family.
My sincere thanks go to all lecturers and members of the staff of the Faculty of
Electronics and Computer Engineering, UTeM, who helped me in many ways and
made my education journey at UTeM pleasant and unforgettable. This three years
experience with all you guys will be remembered as an important memory for me to
face the new chapter of life as an engineer.
I would like to thank my family, especially my loving parents for their love,
dream and sacrifice throughout my life. I am really thankful for their sacrifice,
patience, and understanding that were inevitable to make this work possible. Their
sacrifice had inspired me from the day I learned how to read and write until what I
vii
have become now. I cannot find the appropriate words that could properly describe my
appreciation for their devotion, support and faith in my ability to achieve my dreams.
Not to forget to all my supported siblings and my big family. I also would like to
express special thanks to all my friends for their valuable information, various
suggestions in improving the project and their cooperation towards the success of this
project.
Lastly, I would like to thanks any person which contributes to my final year
project directly on indirectly. I would like to acknowledge their comments and
suggestions, which was crucial for the successful completion of this study.
viii
ABSTRACT
Day by day new technologies are making our life simpler. This project
describes the development of a multiple wireless power transfer for the purpose of
demonstrating wireless power transfer. Wireless power transfer through resonant
inductive coupling could be one of the next technologies that bring the future nearer.
Wireless power transfer is a technique that converts energy from radio frequency (RF)
electromagnetic (EM) waves into DC voltage, which has been used here for the
purpose of providing a power supply to low power devices. In this project it has been
shown that it is possible to charge low power devices wirelessly via resonant inductive
coupling such as mobile phones without the need of wires and cables between the
power source and the power destination. It minimizes the complexity that arises for
the use of conventional wire system. In addition, the project also opens up new
possibilities of wireless systems in our other daily life uses. The system will
demonstrate wireless power transfer by charging a mobile phone. The project will
discuss the performance of the system and explore how better power levels and
efficiencies can be obtained.
ix
ABSTRAK
Hari demi hari teknologi baru membuat kehidupan kita lebih mudah. Projek ini
menerangkan perkembangan pemindahan tenaga secara wayarles bagi tujuan
menunjukkan pemindahan tenaga secara wayarles. Pemindahan tenaga secara
wayarles melalui gandingan induktif resonan boleh menjadi salah satu teknologi akan
datang yang akan membawa masa depan lebih hampir. Pemindahan tenaga wayarles
adalah satu teknik yang menukarkan tenaga daripada frekuensi radio (RF)
elektromagnetik (EM) gelombang ke DC voltan, yang telah digunakan di sini untuk
tujuan menyediakan bekalan kuasa untuk peranti-peranti kuasa rendah. Dalam projek
ini, telah menunjukkan bahawa adalah mungkin untuk mengecas peranti kuasa rendah
secara wayarles melalui gandingan induktif resonan seperti telefon bimbit tanpa
memerlukan wayar dan kabel antara sumber kuasa dan destinasi kuasa. Ia
mengurangkan kerumitan yang timbul bagi penggunaan sistem wayar konvensional.
Di samping itu, projek ini juga membuka kemungkinan baru bahawasanya sistem
wayarles boleh dingunakan di dalam kehidupan seharian. Sistem ini akan
menunjukkan pemindahan tenaga secara wayarles dengan mengecas telefon mudah
alih. Projek ini akan membincangkan prestasi sistem dan meneroka bagaimana tahap
kuasa yang lebih baik dan kecekapan yang boleh diperolehi.
x
TABLE OF CONTENTS
CHAPTER
CONTENT
PROJECT TITLE
i
DECLARATION STATUS OF REPORT FORM
ii
DECLARATION
iii
SUPERVISOR DECLARATION
iv
DEDICATION
v
ACKNOWLEDGEMENT
vi
ABSTRACT
viii
ABSTRAK
ix
TABLE OF CONTENTS
x
LIST OF TABLE
xiv
LIST OF FIGURE
xv
LIST OF APPENDIX
I
PAGE
xviii
INTRODUCTION
1.1
Project Background
2
1.2
Project Objectives
4
1.3
Problem Statement
5
1.4
Scope of Project
6
1.5
System Operation
7
1.6
Organization of the Report
8
1.7
Motivation
9
xi
II
LITERATURE REVIEW
2.1
Summary of Previous Project
10
2.2
Historical Background
14
2.3
Inductive coupling
16
2.3.1
2.4
2.5
III
Magnetic Field Due To Moving Charges
And Electric Currents
18
2.3.3
Inductive Charging
19
2.3.4
Resonant Frequency
20
2.3.5
Resonant Inductive Coupling
21
2.3.6
Coupling Factor
23
2.3.7 Quality Factor
24
2.3.8
25
General Expression for Transformer Efficiency
Nominal Specifications for Charging a Battery
of Mobile Phone
25
The Specification for Efficient Power Charging
29
2.5.1
The Wireless Power Consortium
29
2.5.2
Electromagnetic Shielding
31
METHODOLOGY
3.1
Planning
34
3.1.1
Data Collection
34
3.1.2
Hardware and Software Requirement
35
3.2
Simulation
37
3.3
Layout Design
38
3.4
Implementing
39
3.4.1
39
Project Board Circuit (PCB)
3.5
Checking
42
3.6
Analysis
42
3.7
Development of a Multiple Wireless Power Transfer
43
3.7.1
Transmitter Circuit
44
3.7.2
Receiver Circuit
49
xii
3.8
IV
Flowchart of Methodology Process
RESULT AND DISCUSSION
4.1
Implementation
54
4.2
Simulation Results
56
4.2.1
Transmitter Circuit
56
4.2.2
Receiver Circuit
58
4.3
4.4
Printed Circuit Board Development
60
4.3.1
The PCB Layout of Transmitter Circuit
61
4.3.2
The PCB Layout of Receiver Circuit
62
Hardware construction
4.4.1
V
51
62
Designing Copper Coil for Transmitter
and Receiver Circuit
62
4.4.2
Circuit Construction
65
4.4.3
Development Of Prototype
66
4.5
Measured Result Analysis
67
4.6
Troubleshoot circuit
69
4.7
Discussion
71
CONCLUSION AND RECOMMENDATION
5.1
Conclusion
72
5.2
Recommendation
73
xiii
REFERENCES
74
APPENDIX A
76
APPENDIX B
77
APPENDIX C
85
APPENDIX D
88
APPENDIX E
89
APPENDIX F
95
xiv
LIST OF TABLES
NO
TITLE
PAGE
2.1
Nominal Specifications For Lithium-ion Rechargeable Cell
27
3.1
The Dimensions of The Primary Coil
48
3.2
The Specification of 23 AWG Wire
48
4.1
Output Voltage of Transmitter Circuit by Simulation
58
4.2
Induced Voltage of Receiver Circuit
60
4.3
The Analysis in Designing a Coil
63
4.4
Input and Output of Coils
67
4.5
Range Charge Device and Induced Voltage
68
xv
LIST OF FIGURES
NO
TITLE
1.1
Simplified Drawing of Condition for Wireless
PAGE
Power Transfer to Mobile Devices
3
1.2
Scope of Project
6
1.3
Process of Multiple Wireless Power Transfer System
7
2.1
Block Diagram of the Contactless Charging System
11
2.2
Coupled Model
11
2.3
Primary Side with Reflected Impedance
12
2.4
Input Impedance Spectra for Different Couplings Showing
13
Two Typical Resonances
2.5
Distance Impacts Coil to Coil Efficiency
14
2.6
Arrangement of a Wireless Inductive Power Transmission System
17
2.7
Right Hand Grip Rule
18
2.8
Resonant Frequency
20
2.9
Resonant Coupled Windings with Resonant Capacitors
21
2.10
Strongly Coupled Transformer
24
2.11
Inductive Charging
26
2.12
Equivalent Circuit Charging Li-Ion Cell
28
2.13
Current and Voltage of a Li-Ion Cell Charging Using CC-CV Method
28
2.14
�
Logo
29
2.15
Member Companies of WPC
29
2.16
Typical Wireless-Power Functional Diagram
30
3.1
System Development Life Cycle (SDLC) Phase
32
3.2
Methodology
33
3.3
Transmitter Circuit Diagram
35
xvi
3.4
Receiver Circuit Diagram
36
3.5
Simulation Results by Multisim Software
37
3.6
The Fabrication Process
41
3.7
Block Diagram of Multiple Wireless Power Transfer System
43
3.8
Power Conversation Unit
44
3.9
The Adapter 12V DC
44
3.10
MOSFET IRFZ44N
46
3.11
Half Bridge Inverter
46
3.12
The Simple Parallel Resonant Circuit
47
3.13
Primary Coil Design
47
3.14
AWG Coil
48
3.15
Receiver Side
49
3.16
A Full-Wave Rectifier Circuit Using 4 Diodes
49
3.17
LM7805 Pinout Diagram
50
3.18
Flowchart of Final Year Project
53
4.1
Step How to Use The System
55
4.2
AC Signal Resulting In a Form of Triangle Wave
57
4.3
Transmitter Circuit
57
4.4
Output Waveform across Primary Coil in Transmitter Circuit
58
4.5
Receiver Circuit
59
4.6
Output Waveform across Secondary Coil in Receiver Circuit
59
4.7
Simulation Output for Receiver Circuit
59
4.8
PCB Layout of Transmitter Circuit
61
4.9
Back View of Transmitter Layout
61
4.10
Front View of Transmitter Layout
61
4.11
Back View of Receiver Layout
62
4.12
Front View of Receiver Layout
62
4.13
Designing Copper Coil for Transmitter and Receiver Circuit
63
4.14
Relationship between Number of Turns and Induced Voltage
64
4.15
Relationship between Diameter of Designed Coil and Induced Voltage
64
4.16
Transmitter Module
65
4.17
Receiver Module
65
4.18
Prototype of Multiple Wireless Power Transfer for Demonstration
66
4.19
Installing Transmitter Module and Receiver Module into Casing
66
xvii
4.20
The Analysis of Range to Charge a Device
68
4.21
Troubleshoot on Receiver Circuit
69
4.22
Dropping of Input Voltage
69
4.23
Replacement of New Diode on Trnsmitter Circuit
70
xviii
LIST OF APPENDIX
NO
TITLE
PAGE
A
Gantt Chart
76
B
IRFZ44N Datasheet
77
C
LM7805 Datasheet
86
D
Measured Inductance and Resonant Frequency
89
E
Guidelines for MOSFET Selection
90
F
Lithium-Ion Rechargeable Cell for Power Tools
96
1
CHAPTER 1
INTRODUCTION
New technologies emerge each and every day to make our life simpler. Despite
all these, we still rely on the classical and conventional wire system to charge our
everyday use low power devices such as mobile phones, digital camera etc. and even
mid power devices such as laptops. The conventional wire system creates a mess when
it comes to charging several devices simultaneously. It also takes up a lot of electric
sockets and not to mention the fact that each device has its own design for the charging
port. At this point a question might arise, “What if a single device can be used to charge
these devices simultaneously without the use of wires and not creating a mess in the
process?” The solution to all these dilemmas lies with inductive coupling, a simple and
effective way of transferring power wirelessly
This chapter introduces the general overview and background of this project
with the title “Multiple Wireless Power Transfer System”. This project is expected to
use a resonant inductive coupling technique. This chapter is divided into seven
sections. In section one gives the general preview of this chapter. Section two gives a
simple explanation of the background of the project and then continued with project
motivation. Next, constructing the problem statement by summarizing with the current
problem faced is being discussed in section four. Section five defines the objective of
this project as a guideline to the solutions of the problems faced. The scope of the
project is being described in section six. Finally, section seven will conclude the
organization of the report. It is a summary of the report in developing this project. One
2
of the main purpose of this project is to compare different wireless power transfer
development against each other’s and do enhancement on the current WPT system.
1.1
Project Background
Wireless Power Transmission (WPT) is the efficient transmission of electric
power from one point to another trough air without the use of wire or any other
substance. This can be used for applications where either an instantaneous amount or
a continuous delivery of energy is needed, but where conventional wires are
unaffordable, inconvenient, expensive, hazardous, unwanted or impossible. The power
can be transmitted using inductive coupling for short range, resonant induction for
mid-range and electromagnetic wave power transfer for high range. This project will
be developed by using near field or non-radiative method which is for mid-range.
Charging low power devices and eventually mid power devices by means of inductive
coupling could be the next big thing
Multiple wireless power transfer described in this project is motivated by the
potential application of resonant inductive coupling as a means for wireless power
transfer from a source coil to multiple receivers. Resonance inductive coupling
technology has been implemented with biomedical and consumer electronics
applications that demand higher power levels than previous wirelessly powered
devices [1], [2], [3]. As the power levels increase, efficiency and range become
important design considerations because these criteria determine the required amount
of power transmitted to sufficiently power a load. Magnetic resonance coupling
technology has been implemented with biomedical and consumer electronics
applications that demand higher power levels than previous wirelessly powered
devices. The industry realizes the demand for wireless power charging where mobile
devices can be charged without the need for connecting wires.
WPT devices have been thought to be possible since Nikola Tesla’s
transmission model in 1897. The newest technologies rely on inductive coupling
techniques to transmit power between transmitting and receiving coils. The most
common and probably the oldest consumer application of wireless energy transfer can
3
be found in the electric toothbrush [4]. The frequency at which the device transfers
power between the transmitter and receiver is dependent on the size of the coils. The
higher the frequency at which the device is transmitting, the smaller the transmitting
and receiving coils must be. Figure 1.1 shows the simplified drawing of condition for
wireless power transfer to mobile devices where primary components in any WPT
system are the coils.
Figure 1.1: Simplified Drawing of Condition for Wireless Power Transfer to Mobile
Devices
The system is broken into two parts, the transmitter circuit which provides
power for wireless transfer and the receiver circuit, which is the mobile device that
consumes the power. The power transmitter circuit contains the primary coil, the series
resonant capacitor and a DC to AC inverter that inverters the DC power supply into
the AC voltage needed to induce a magnetic field between the two coils. The power
receiver circuit contains the secondary coil, a parallel resonant capacitor and an AC to
DC converter. The primary and secondary coils form two halves of a resonant
transformer. To demonstrate that power was successfully transferred wirelessly, a
mobile phone was charged and there are multiple loads in wireless power transfer
systems. The amount of power transmitted and effectively received will depend on
how well the coils are designed.
Inductive coupling is an old and well-understood method of wireless power
transfer. The source drives a primary coil, creating a sinusoidal varying magnetic field,
4
which induces a voltage across the terminals of a secondary coil, and thus transfers
power to a load. This mechanism, responsible for power transfer in a transformer,
where the magnetic field is typically confined to a high permeability core, also
functions when the region between the primary and secondary coils is simply air.
Inductive coupling without high permeability cores is used, for example, to power
RFID tags and medical implants [5]. A common technique for increasing the voltage
received by the device to be powered is to add a parallel capacitor to the secondary to
form a resonant circuit at the operating frequency [6], [7].
1.2
Project Objectives
The main objective of this project is to build a multiple wireless power transfer.
In order to make this project successful, the objectives have been declared these
objectives must be achieved in completing this project. Objectives are a guidance of
any project, so the objectives have been listed below.
i.
To design and construct a method to transmit wireless electrical power through
space.
ii.
To design multiple port wireless power transfer system over range of few
centimeters transmission distance using mid range technology.
iii.
To develop a system of wireless power transfer for multiple small receivers
iv.
To study a system that was capable of charging a mobile phone using the
resonant inductive coupling technique.
5
1.3
Problem Statements
There are several problems based on recent way of wireless power transfer.
Firstly, today most rechargeable, portable electronic devices comes with their own
proprietary charger and cables. An average user of mobile electronic devices carries at
least three different chargers and at least an equal number of cables for energy charging
and data transfer functions. Cell phone consumer frustration encompasses not only the
inability to make or receive a call because of a dead battery, but also addressing the
added cost and inconvenience of juggling multiple chargers (at home, in the car, at the
office, etc.). This has led to changing consumer expectations to charge mobile devices
wirelessly, potentially eliminate the use of cables and chargers, and help mitigate the
“inconvenience” associated with carrying external chargers and cables.
Next, current wireless power transfer is capable of transmitting current at
distances of less than one inch. These distances allow for use in small consumer
electronic devices such as electric toothbrushes and razors [4]. While these
applications have proven to be profitable, the market still remains open for use in larger
electronic devices. An aspect of WPT that has been largely unexplored is the ability to
charge batteries and other electronic circuits.
Finally, wireless power technology is in high demand because of its
convenience to consumer and industrial marketplaces. While wireless power devices
have already been created by other companies and institutions, but they are still basic
and not practical.
SAIDAH BINTI MUHTAR LUBIS
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
i
MULTIPLE WIRELESS POWER TRANSFER SYSTEM
SAIDAH BINTI MUHTAR LUBIS
This Report is Submitted in Partial Fulfillment of the Requirement for the Bachelor
Degree in Electronic Engineering (Wireless Communication) With Honours
Fakulti Kejuruteraan Elektronik dan Kejuruteraan Komputer
Universiti Teknikal Malaysia Melaka
June 2015
ii
iii
iv
v
DEDICATION
Dedicated to my beloved supervisor, lecturer, my family and all my friends.
vi
ACKNOWLEDGEMENT
I am grateful to ALLAH S.W.T for the good health and wellbeing that were
necessary to complete this thesis report. Alharndulillah, all Praise to thank to Allah
S.W.T the Almighty for giving me the Rahmah to finish my project successfully. I
would like to take this golden opportunity to express my appreciation and heartfelt
gratitude to my supervisor, Eng. Noor Badariah Binti Asan for the opportunity given
to me to do this project and for his belief. I really appreciate her guidance from the
initial to the final level that enabled me to develop an understanding of this research
thoroughly. Thank you very much for her endless support and ideas, during which she
has been patiently supervising my progress and encouraged me to do this project in the
right way. With full of hope, Allah SWT bless Her and family.
My sincere thanks go to all lecturers and members of the staff of the Faculty of
Electronics and Computer Engineering, UTeM, who helped me in many ways and
made my education journey at UTeM pleasant and unforgettable. This three years
experience with all you guys will be remembered as an important memory for me to
face the new chapter of life as an engineer.
I would like to thank my family, especially my loving parents for their love,
dream and sacrifice throughout my life. I am really thankful for their sacrifice,
patience, and understanding that were inevitable to make this work possible. Their
sacrifice had inspired me from the day I learned how to read and write until what I
vii
have become now. I cannot find the appropriate words that could properly describe my
appreciation for their devotion, support and faith in my ability to achieve my dreams.
Not to forget to all my supported siblings and my big family. I also would like to
express special thanks to all my friends for their valuable information, various
suggestions in improving the project and their cooperation towards the success of this
project.
Lastly, I would like to thanks any person which contributes to my final year
project directly on indirectly. I would like to acknowledge their comments and
suggestions, which was crucial for the successful completion of this study.
viii
ABSTRACT
Day by day new technologies are making our life simpler. This project
describes the development of a multiple wireless power transfer for the purpose of
demonstrating wireless power transfer. Wireless power transfer through resonant
inductive coupling could be one of the next technologies that bring the future nearer.
Wireless power transfer is a technique that converts energy from radio frequency (RF)
electromagnetic (EM) waves into DC voltage, which has been used here for the
purpose of providing a power supply to low power devices. In this project it has been
shown that it is possible to charge low power devices wirelessly via resonant inductive
coupling such as mobile phones without the need of wires and cables between the
power source and the power destination. It minimizes the complexity that arises for
the use of conventional wire system. In addition, the project also opens up new
possibilities of wireless systems in our other daily life uses. The system will
demonstrate wireless power transfer by charging a mobile phone. The project will
discuss the performance of the system and explore how better power levels and
efficiencies can be obtained.
ix
ABSTRAK
Hari demi hari teknologi baru membuat kehidupan kita lebih mudah. Projek ini
menerangkan perkembangan pemindahan tenaga secara wayarles bagi tujuan
menunjukkan pemindahan tenaga secara wayarles. Pemindahan tenaga secara
wayarles melalui gandingan induktif resonan boleh menjadi salah satu teknologi akan
datang yang akan membawa masa depan lebih hampir. Pemindahan tenaga wayarles
adalah satu teknik yang menukarkan tenaga daripada frekuensi radio (RF)
elektromagnetik (EM) gelombang ke DC voltan, yang telah digunakan di sini untuk
tujuan menyediakan bekalan kuasa untuk peranti-peranti kuasa rendah. Dalam projek
ini, telah menunjukkan bahawa adalah mungkin untuk mengecas peranti kuasa rendah
secara wayarles melalui gandingan induktif resonan seperti telefon bimbit tanpa
memerlukan wayar dan kabel antara sumber kuasa dan destinasi kuasa. Ia
mengurangkan kerumitan yang timbul bagi penggunaan sistem wayar konvensional.
Di samping itu, projek ini juga membuka kemungkinan baru bahawasanya sistem
wayarles boleh dingunakan di dalam kehidupan seharian. Sistem ini akan
menunjukkan pemindahan tenaga secara wayarles dengan mengecas telefon mudah
alih. Projek ini akan membincangkan prestasi sistem dan meneroka bagaimana tahap
kuasa yang lebih baik dan kecekapan yang boleh diperolehi.
x
TABLE OF CONTENTS
CHAPTER
CONTENT
PROJECT TITLE
i
DECLARATION STATUS OF REPORT FORM
ii
DECLARATION
iii
SUPERVISOR DECLARATION
iv
DEDICATION
v
ACKNOWLEDGEMENT
vi
ABSTRACT
viii
ABSTRAK
ix
TABLE OF CONTENTS
x
LIST OF TABLE
xiv
LIST OF FIGURE
xv
LIST OF APPENDIX
I
PAGE
xviii
INTRODUCTION
1.1
Project Background
2
1.2
Project Objectives
4
1.3
Problem Statement
5
1.4
Scope of Project
6
1.5
System Operation
7
1.6
Organization of the Report
8
1.7
Motivation
9
xi
II
LITERATURE REVIEW
2.1
Summary of Previous Project
10
2.2
Historical Background
14
2.3
Inductive coupling
16
2.3.1
2.4
2.5
III
Magnetic Field Due To Moving Charges
And Electric Currents
18
2.3.3
Inductive Charging
19
2.3.4
Resonant Frequency
20
2.3.5
Resonant Inductive Coupling
21
2.3.6
Coupling Factor
23
2.3.7 Quality Factor
24
2.3.8
25
General Expression for Transformer Efficiency
Nominal Specifications for Charging a Battery
of Mobile Phone
25
The Specification for Efficient Power Charging
29
2.5.1
The Wireless Power Consortium
29
2.5.2
Electromagnetic Shielding
31
METHODOLOGY
3.1
Planning
34
3.1.1
Data Collection
34
3.1.2
Hardware and Software Requirement
35
3.2
Simulation
37
3.3
Layout Design
38
3.4
Implementing
39
3.4.1
39
Project Board Circuit (PCB)
3.5
Checking
42
3.6
Analysis
42
3.7
Development of a Multiple Wireless Power Transfer
43
3.7.1
Transmitter Circuit
44
3.7.2
Receiver Circuit
49
xii
3.8
IV
Flowchart of Methodology Process
RESULT AND DISCUSSION
4.1
Implementation
54
4.2
Simulation Results
56
4.2.1
Transmitter Circuit
56
4.2.2
Receiver Circuit
58
4.3
4.4
Printed Circuit Board Development
60
4.3.1
The PCB Layout of Transmitter Circuit
61
4.3.2
The PCB Layout of Receiver Circuit
62
Hardware construction
4.4.1
V
51
62
Designing Copper Coil for Transmitter
and Receiver Circuit
62
4.4.2
Circuit Construction
65
4.4.3
Development Of Prototype
66
4.5
Measured Result Analysis
67
4.6
Troubleshoot circuit
69
4.7
Discussion
71
CONCLUSION AND RECOMMENDATION
5.1
Conclusion
72
5.2
Recommendation
73
xiii
REFERENCES
74
APPENDIX A
76
APPENDIX B
77
APPENDIX C
85
APPENDIX D
88
APPENDIX E
89
APPENDIX F
95
xiv
LIST OF TABLES
NO
TITLE
PAGE
2.1
Nominal Specifications For Lithium-ion Rechargeable Cell
27
3.1
The Dimensions of The Primary Coil
48
3.2
The Specification of 23 AWG Wire
48
4.1
Output Voltage of Transmitter Circuit by Simulation
58
4.2
Induced Voltage of Receiver Circuit
60
4.3
The Analysis in Designing a Coil
63
4.4
Input and Output of Coils
67
4.5
Range Charge Device and Induced Voltage
68
xv
LIST OF FIGURES
NO
TITLE
1.1
Simplified Drawing of Condition for Wireless
PAGE
Power Transfer to Mobile Devices
3
1.2
Scope of Project
6
1.3
Process of Multiple Wireless Power Transfer System
7
2.1
Block Diagram of the Contactless Charging System
11
2.2
Coupled Model
11
2.3
Primary Side with Reflected Impedance
12
2.4
Input Impedance Spectra for Different Couplings Showing
13
Two Typical Resonances
2.5
Distance Impacts Coil to Coil Efficiency
14
2.6
Arrangement of a Wireless Inductive Power Transmission System
17
2.7
Right Hand Grip Rule
18
2.8
Resonant Frequency
20
2.9
Resonant Coupled Windings with Resonant Capacitors
21
2.10
Strongly Coupled Transformer
24
2.11
Inductive Charging
26
2.12
Equivalent Circuit Charging Li-Ion Cell
28
2.13
Current and Voltage of a Li-Ion Cell Charging Using CC-CV Method
28
2.14
�
Logo
29
2.15
Member Companies of WPC
29
2.16
Typical Wireless-Power Functional Diagram
30
3.1
System Development Life Cycle (SDLC) Phase
32
3.2
Methodology
33
3.3
Transmitter Circuit Diagram
35
xvi
3.4
Receiver Circuit Diagram
36
3.5
Simulation Results by Multisim Software
37
3.6
The Fabrication Process
41
3.7
Block Diagram of Multiple Wireless Power Transfer System
43
3.8
Power Conversation Unit
44
3.9
The Adapter 12V DC
44
3.10
MOSFET IRFZ44N
46
3.11
Half Bridge Inverter
46
3.12
The Simple Parallel Resonant Circuit
47
3.13
Primary Coil Design
47
3.14
AWG Coil
48
3.15
Receiver Side
49
3.16
A Full-Wave Rectifier Circuit Using 4 Diodes
49
3.17
LM7805 Pinout Diagram
50
3.18
Flowchart of Final Year Project
53
4.1
Step How to Use The System
55
4.2
AC Signal Resulting In a Form of Triangle Wave
57
4.3
Transmitter Circuit
57
4.4
Output Waveform across Primary Coil in Transmitter Circuit
58
4.5
Receiver Circuit
59
4.6
Output Waveform across Secondary Coil in Receiver Circuit
59
4.7
Simulation Output for Receiver Circuit
59
4.8
PCB Layout of Transmitter Circuit
61
4.9
Back View of Transmitter Layout
61
4.10
Front View of Transmitter Layout
61
4.11
Back View of Receiver Layout
62
4.12
Front View of Receiver Layout
62
4.13
Designing Copper Coil for Transmitter and Receiver Circuit
63
4.14
Relationship between Number of Turns and Induced Voltage
64
4.15
Relationship between Diameter of Designed Coil and Induced Voltage
64
4.16
Transmitter Module
65
4.17
Receiver Module
65
4.18
Prototype of Multiple Wireless Power Transfer for Demonstration
66
4.19
Installing Transmitter Module and Receiver Module into Casing
66
xvii
4.20
The Analysis of Range to Charge a Device
68
4.21
Troubleshoot on Receiver Circuit
69
4.22
Dropping of Input Voltage
69
4.23
Replacement of New Diode on Trnsmitter Circuit
70
xviii
LIST OF APPENDIX
NO
TITLE
PAGE
A
Gantt Chart
76
B
IRFZ44N Datasheet
77
C
LM7805 Datasheet
86
D
Measured Inductance and Resonant Frequency
89
E
Guidelines for MOSFET Selection
90
F
Lithium-Ion Rechargeable Cell for Power Tools
96
1
CHAPTER 1
INTRODUCTION
New technologies emerge each and every day to make our life simpler. Despite
all these, we still rely on the classical and conventional wire system to charge our
everyday use low power devices such as mobile phones, digital camera etc. and even
mid power devices such as laptops. The conventional wire system creates a mess when
it comes to charging several devices simultaneously. It also takes up a lot of electric
sockets and not to mention the fact that each device has its own design for the charging
port. At this point a question might arise, “What if a single device can be used to charge
these devices simultaneously without the use of wires and not creating a mess in the
process?” The solution to all these dilemmas lies with inductive coupling, a simple and
effective way of transferring power wirelessly
This chapter introduces the general overview and background of this project
with the title “Multiple Wireless Power Transfer System”. This project is expected to
use a resonant inductive coupling technique. This chapter is divided into seven
sections. In section one gives the general preview of this chapter. Section two gives a
simple explanation of the background of the project and then continued with project
motivation. Next, constructing the problem statement by summarizing with the current
problem faced is being discussed in section four. Section five defines the objective of
this project as a guideline to the solutions of the problems faced. The scope of the
project is being described in section six. Finally, section seven will conclude the
organization of the report. It is a summary of the report in developing this project. One
2
of the main purpose of this project is to compare different wireless power transfer
development against each other’s and do enhancement on the current WPT system.
1.1
Project Background
Wireless Power Transmission (WPT) is the efficient transmission of electric
power from one point to another trough air without the use of wire or any other
substance. This can be used for applications where either an instantaneous amount or
a continuous delivery of energy is needed, but where conventional wires are
unaffordable, inconvenient, expensive, hazardous, unwanted or impossible. The power
can be transmitted using inductive coupling for short range, resonant induction for
mid-range and electromagnetic wave power transfer for high range. This project will
be developed by using near field or non-radiative method which is for mid-range.
Charging low power devices and eventually mid power devices by means of inductive
coupling could be the next big thing
Multiple wireless power transfer described in this project is motivated by the
potential application of resonant inductive coupling as a means for wireless power
transfer from a source coil to multiple receivers. Resonance inductive coupling
technology has been implemented with biomedical and consumer electronics
applications that demand higher power levels than previous wirelessly powered
devices [1], [2], [3]. As the power levels increase, efficiency and range become
important design considerations because these criteria determine the required amount
of power transmitted to sufficiently power a load. Magnetic resonance coupling
technology has been implemented with biomedical and consumer electronics
applications that demand higher power levels than previous wirelessly powered
devices. The industry realizes the demand for wireless power charging where mobile
devices can be charged without the need for connecting wires.
WPT devices have been thought to be possible since Nikola Tesla’s
transmission model in 1897. The newest technologies rely on inductive coupling
techniques to transmit power between transmitting and receiving coils. The most
common and probably the oldest consumer application of wireless energy transfer can
3
be found in the electric toothbrush [4]. The frequency at which the device transfers
power between the transmitter and receiver is dependent on the size of the coils. The
higher the frequency at which the device is transmitting, the smaller the transmitting
and receiving coils must be. Figure 1.1 shows the simplified drawing of condition for
wireless power transfer to mobile devices where primary components in any WPT
system are the coils.
Figure 1.1: Simplified Drawing of Condition for Wireless Power Transfer to Mobile
Devices
The system is broken into two parts, the transmitter circuit which provides
power for wireless transfer and the receiver circuit, which is the mobile device that
consumes the power. The power transmitter circuit contains the primary coil, the series
resonant capacitor and a DC to AC inverter that inverters the DC power supply into
the AC voltage needed to induce a magnetic field between the two coils. The power
receiver circuit contains the secondary coil, a parallel resonant capacitor and an AC to
DC converter. The primary and secondary coils form two halves of a resonant
transformer. To demonstrate that power was successfully transferred wirelessly, a
mobile phone was charged and there are multiple loads in wireless power transfer
systems. The amount of power transmitted and effectively received will depend on
how well the coils are designed.
Inductive coupling is an old and well-understood method of wireless power
transfer. The source drives a primary coil, creating a sinusoidal varying magnetic field,
4
which induces a voltage across the terminals of a secondary coil, and thus transfers
power to a load. This mechanism, responsible for power transfer in a transformer,
where the magnetic field is typically confined to a high permeability core, also
functions when the region between the primary and secondary coils is simply air.
Inductive coupling without high permeability cores is used, for example, to power
RFID tags and medical implants [5]. A common technique for increasing the voltage
received by the device to be powered is to add a parallel capacitor to the secondary to
form a resonant circuit at the operating frequency [6], [7].
1.2
Project Objectives
The main objective of this project is to build a multiple wireless power transfer.
In order to make this project successful, the objectives have been declared these
objectives must be achieved in completing this project. Objectives are a guidance of
any project, so the objectives have been listed below.
i.
To design and construct a method to transmit wireless electrical power through
space.
ii.
To design multiple port wireless power transfer system over range of few
centimeters transmission distance using mid range technology.
iii.
To develop a system of wireless power transfer for multiple small receivers
iv.
To study a system that was capable of charging a mobile phone using the
resonant inductive coupling technique.
5
1.3
Problem Statements
There are several problems based on recent way of wireless power transfer.
Firstly, today most rechargeable, portable electronic devices comes with their own
proprietary charger and cables. An average user of mobile electronic devices carries at
least three different chargers and at least an equal number of cables for energy charging
and data transfer functions. Cell phone consumer frustration encompasses not only the
inability to make or receive a call because of a dead battery, but also addressing the
added cost and inconvenience of juggling multiple chargers (at home, in the car, at the
office, etc.). This has led to changing consumer expectations to charge mobile devices
wirelessly, potentially eliminate the use of cables and chargers, and help mitigate the
“inconvenience” associated with carrying external chargers and cables.
Next, current wireless power transfer is capable of transmitting current at
distances of less than one inch. These distances allow for use in small consumer
electronic devices such as electric toothbrushes and razors [4]. While these
applications have proven to be profitable, the market still remains open for use in larger
electronic devices. An aspect of WPT that has been largely unexplored is the ability to
charge batteries and other electronic circuits.
Finally, wireless power technology is in high demand because of its
convenience to consumer and industrial marketplaces. While wireless power devices
have already been created by other companies and institutions, but they are still basic
and not practical.