Abstract
Wireless charging of gadgets is one of the new emerging technologies in the world at the
moment. The most common method used at the moment is wireless power transfer by inductive
coupling. . Wireless power transfer is one of the simplest and inexpensive ways of charging as it
eliminate the use of conventional copper cables and current carrying wires. In this project write
up, a methodology and principle of operation are devised for wireless power transfer through
inductive coupling, and a feasible design is modeled accordingly. The inductive coupling
technique is used since currently it’s the easiest method of wireless power transfer because of
high efficiency and large amount of the energy transferred. In the report paper, results of
experiments done to check wireless working will be shown. Also to further show its versatility
and range of applications the power transferred will be used to charge a battery with the aid of
additional circuitry. We will also study the effect of placing hurdles between the transmitter and
receiver so as to establish if it is an alternative in the medical industry for charging pace makers
etc. This research work focuses on the study of wireless power transfer for the purpose of
transferring energy at maximum efficiency within a small range or in the near field region
Contents
Declaration - - - - - - - - - - - - - - - - - - - - - - ii
Declaration of Originality - - - - - - - - - - - - - - - - - - iii
Dedication - - - - - - - - - - - - - - - - - - - - - - iv
Acknowledgement - - - - - - - - - - - - - - - - - - - - v
LIST OF TABLES - - - - - - - - - - - - - - - - - - - - viii
LIST OF FIGURES - - - - - - - - - - - - - - - - - - - - ix
Abstract - - - - - - - - - - - - - - - - - - - - - - - xi
List of Abbreviations - - - - - - - - - - - - - - - - - - - xii
CHAPTER 1: INTRODUCTION - - - - - - - - - - - - - - - - - 1
11Background - - - - - - - - - - - - - - - - - - - - - 1
12 Problem Statement - - - - - - - - - - - - - - - - - - - 1
13 Objectives - - - - - - - - - - - - - - - - - - - - - 2
131 Overall objective - - - - - - - - - - - - - - - - - - 2
132 Specific objectives - - - - - - - - - - - - - - - - - - 2
14 Justification for the Study - - - - - - - - - - - - - - - - - 2
15 Scope of work - - - - - - - - - - - - - - - - - - - - 3
16 Project Paper Organization - - - - - - - - - - - - - - - - - 3
CHAPTER 2: LITERATURE REVIEW - - - - - - - - - - - - - - - 5
21 Outline of the Chapter - - - - - - - - - - - - - - - - - - 5
22 History of Wireless Power Transfer - - - - - - - - - - - - - - 5
23 Main concepts of wireless transmission of electric energy - - - - - - - - - 6
24 Health and safety considerations - - - - - - - - - - - - - - - 9
25 WPT Standards and Alliances - - - - - - - - - - - - - - - - 10
Qi by the Wireless Power Consortium (WPC) - - - - - - - - - - - - 10
Rezence by the Alliance for Wireless Power (A4WP) - - - - - - - - - - 10
Power Matters Alliance (PMA) - - - - - - - - - - - - - - - - 10
CHAPTER 3: THEORETICAL FRAMEWORK - - - - - - - - - - - - 12
CHAPTER 4: METHODS AND MATERIALS - - - - - - - - - - - - 17
41 General Principle of Design - - - - - - - - - - - - - - - - 17
42Hardware and Software Components - - - - - - - - - - - - - -
20
4211Power Supply - - - - - - - - - - - - - - - - - - 21
4212DC - DC Boost Converter - - - - - - - - - - - - - - - 21
4213 Royer Oscillator - - - - - - - - - - - - - - - - - - 22
4214 Full Wave Bridge Rectifier - - - - - - - - - - - - - - - 23
4215 The Microcontroller Unit - - - - - - - - - - - - - - - 25
4216 The LCD Screen - - - - - - - - - - - - - - - - - 28
4217 Switching Circuit - - - - - - - - - - - - - - - - - 30
422 Software - - - - - - - - - - - - - - - - - - - - - 31
4221USBasp - - - - - - - - - - - - - - - - - - - - 31
4222 Programming Language - - - - - - - - - - - - - - - 32
CHAPTER 5: RESULTS AND DISCUSSIONS - - - - - - - - - - - - 34
51 Results - - - - - - - - - - - - - - - - - - - - - - 34
52 Analysis and Discussion - - - - - - - - - - - - - - - - - 37
CHAPTER 6: CONCLUSIONS AND RECOMMENDATIONS - - - - - - - - 40
61 Conclusions - - - - - - - - - - - - - - - - - - - - 40
62 Recommendations - - - - - - - - - - - - - - - - - - 41
REFERENCES - - - - - - - - - - - - - - - - - - - - - 42
APPENDICES - - - - - - - - - - - - - - - - - - - - - 43
CHAPTER 1: INTRODUCTION
11Background
If you are using an electronic device perhaps a mobile phone and you need to recharge the
battery then you will probably have to get a charger and connect the phone to the wire But what
if you could charge it without having to connect it to wire? Meaning power will be transferred
wirelessly This is possible through a concept called Wireless Power Transmission Research and
studies have been done ever since the 19th century but it is only recently that this concept has
begun to be implemented
Currently engineers are trying to discover how to increase the efficiency of power transmitted
wirelessly and also methods that that are safe to human beings and the environment and
notwithstanding, methods that are cheaper and hence can be commercially viable Though still in
the early stages, several electronic companies are beginning to roll out devices that can
wirelessly transmit power
Wireless power transmission (WPT) is based on the principle of electromagnetic induction
Electromagnetic induction works on the concept of a primary coil generating a predominantly
magnetic field and a secondary coil being within that field so a current is induced within its coils
This causes the relatively short range due to the amount of power required to produce an
electromagnetic field
12 Problem Statement
The project seeks to eliminate the use of wires in the transmission of power from the source to
the device to be powered Although WPT is based on electromagnetic induction, there are
various methods that are used Some are less efficient than others and costly while others don’t
allow for a longer range of transmission In this project, it is required to design and construct an
electronic device that shall transmit power within a small range The device can then be used to
charge batteries for devices like pace makers
In the project a suitable method will be used to ensure that enough power is transmitted
wirelessly so that it can then charge batteries The major challenge will be in the coupling circuit
which comprises of the coils where electromagnetic induction occurs The number of turns of the
coil, inductance
13 Objectives
The project has a main objective whose achievement is aided by breaking it further down into
other smaller specific objectives This helps in showing comprehensively how the final objective
of the project is achieved in a clear and concise manner 131 Overall objective
The main objective of the project is to develop a device for wireless power transfer
132 Specific objectives
The project will be divided into the following specific objectives that will aid in achieving the
main objective ï‚Â� Design and assemble a power supply unit ï‚Â� Step up the dc supply ï‚Â� Design and assemble an appropriate oscillator ï‚Â� Develop transmitter and receiver coils ï‚Â� Design the receiver module and rectify the ac voltage received on the receiver
coil ï‚Â� Designing a battery charging circuit
14 Justification for the Study
The need for devices that can wirelessly transmit power has over the years increased Currently a
lot of research is being conducted in order to obtain suitable methods that can be used in the
development of such devices The following are reasons why it is important
a) Flexibility: WPT will eliminate the use of conductors and wires Rather than have
many wires running from a power source to power devices, the power can be
transmitted wirelessly hence the mess caused by cables can be avoided and also more
devices can be powered without having them all placed next to the power source
b) Safety: With the increase in electrification in areas, cases of electrical shocks have
been rampant as people and even animals end up touching the conductors WPT will
eliminate these conductors hence preventing the electrical shocks
c) Convenience: The application of WPT will enable the convenient use of devices For
example, in the medical field pacemakers which use batteries can be recharged rather
than having a surgery every time the battery life is over This will save on costs for
surgery and also is a more convenient option
d) Reliability: Many times people are using a device and it runs out of power yet one
doesn’t have a cord to charge the device or perhaps there is no source of power
around However with WPT the devices can be charged wirelessly hence the risk of
low battery power will be eliminated
15 Scope of work
This project covers the hardware and software design and implementation of a device that will be
able to transfer power wirelessly The study will look into the methods that are currently in use
and seek to improve on the areas where the performance is low The hardware system will
involve the design and construction of a transmitter and receiver modules Once there is proof
that power has been transmitted, a battery charging circuit will be designed and developed to
charge a 9V battery so as to show the application of a wireless power transfer device The
software system will include code that will control ensure the system is intelligent enough to
determine the battery capacity and also to display the various parameters that are important
16 Project Paper Organization
This project paper comprises five chapters namely: ï‚Â� Chapter 1:Introduction
This gives the project definition, project overview, objectives, project justification and
scope of work
ï‚Â� Chapter 2: Literature Review
This chapter presents information on the evolution and present state of theory, practice
and research of wireless power transmission
ï‚Â� Chapter 3: Theoretical Framework
In this chapter the theory behind the design of the project is given
ï‚Â� Chapter 4: Methodology and Materials
This chapter gives a detailed explanation on how the device once assembled operates It
also explains the components used and their role in the design of each part of the device
ï‚Â� Chapter 5: Results and Analysis
