PIEZOELECTRIC GENERATOR

By

Mohd Ezzuan Bin Ahmad

Dissertation submitted

in partial fulfilment of the requirements

for the Degree

Bachelor of Engineering (Hons)

(Electrical & Electronics Engineering)

MAY20ll

Universiti Teknologi PETRONAS

Bandar Seri Iskandar

31750 Tronoh

Perak Darul Ridzuan

 CERTIFICATION OF APPROVAL

PIEZOELECTRIC GENERATOR

By

Mohd Ezzuan Bin Ahmad

A project dissertation submitted to the

El!lctrical and Electronic Engineering Programme
Universiti Teknologi PETRONAS
in partial fulfilment of the requirement for the
BACHELOR OF ENGINEERING (Hons)
(ELECTRICAL & ELECTRONIC ENGINEERING)

Approved:

Dr. Nursyarizal Mohd Nor

Project Supervisor

Universiti Teknologi PETRONAS

Tronoh, Perak

May201l

ii
 CERTIFICATION OF ORIGINALITY

This is to certizy that I am responsible for the work submitted in this project, that
the original work is my own except as specified in the references and
acknowledgements, and that the original work contained herein have not been
undertaken or done by unspecified sources or persons.

JK_·
(MOHO EZZUAN BIN AHMAD)

iii
 ABSTRACT

Piezoelectric are the materials that can be used to transform ambient

vibrations into electrical energy. This energy than will be stored and used to
power other devices. With the micro scale devices, piezoelectric power generation
can provide an alternative power sources used to operate certain types of sensors
or actuators. Piezoelectric generator is a device that will generate electrical energy
from the vibration sources. This project will pe using a milistructure of bi-morph
piezoelectric material. This material will be used to transfer the ambient vibration
into electrical energy. The piezoelectric generator is implemented on a
motorcycle, where it will absorb the vibration from motorcycle in order to convert
to electrical energy. Motorcycle always produce vibration when on the road, and
thus can be used to generate electrical energy using piezoelectric. This electrical
energy than will be used to power electrical components such as cellular phones,
or any gadgets that required electrical input power. Based on the piezoelectric
concept, it will convert the vibration energy to electrical energy.

iv
 ACKNOWLEDGEMENT

First of all I would like to express my gratitude to god for giving me the
strength and health to complete this project. Not forgotten to my parents and all
my family members for providing everything such as money and advises, which
are most needed in this project. I would like to thank to my supervisor, Dr
Nursyarizal for sharing his knowledge and giving me the support and guidance
throughout this project. I would also like to thank to Dr Haris, who is my co-
supervisor in this project for helping me in doing this project. I believe, without he
help of them, I could not finish this project within the given time. My
appreciation to UTP especially Electrical and Electronic Engineering department ,
by providing me the necessary assets and resources, not least, i offer my regards
to those who support me especially all my friends and lab technicians for
contributing their assistance and ideas for this project.

v
 TABLE OF CONTENS

CERTIFICATION OF APPROVAL. . ii

CERTIFICATION OF ORIGINALITY. iii

ABSTRACT. iv

ACKNOWLEDGEMENT. v

LIST OF FIGURES. ix

LIST OF TABLES. xi

INTRODUCTION. 1-3

1.1 Background of Study. 1

1.2 Problem Statement. 2

1.3 Objective • 2

1.4 Scope of Study. 3

LITERATURE REVIEW. 4-10

2.0 Introduction. 4

2.1 Fundamentals and Theory od Piezoelectric. 4

2.2 Piezoelectric Gemerator Principle. 7-8

2.3 Motorcycle Vibration. 9

2.4 Vibration to Electrical Energy Conversion. 10

METHODOLOGY. 11-13

3.1 Phasese in Piezo Generator. 11

3.1.1 Phase 1.. II

vi
 3.1.2 Phase 2••. II

3.1 .3 Phase 3•• 12

3.1.4 Phase 4 .• 12

3.2 Identification of Appropriate Hardware and Software. 13

3.3 Construct the Base of the Generator .. 14
3.4 Construct the Beam and the Piezoelectric Element. . . 14-15
3.5 Electric Circuit. . 15
3.5.1 Full Bridge Rectifier Circuit.. . 15
3.5.2 BMster Circuit. . 16

RESULT & DISCUSSION. 17-21

4.1 Develop Work Bench for Piezo Generator. 17-18

4.2 Prototype and Circuit Fabrication. 19-21

4.3 Result of Experiment. 22-29

4.2.1 DC Motor Experiment. . 22-24

4.2.2 Manual Vibration Experiment.. 25-27

4.2.3 DC Motor and Prototype experiment. . 28-29

4.3 Discussion. 30-33

4.3.1 Experiment I & 2. 30

4.3.2 Experiment 3. . 31

4.33 Justification of Result. 32-33

CONCLUSION & RECOMMENDATIONS•• 34-35

5.I Conclusion. 34

5.2 Recomendations.. 35

vii
REFERENCES.. 36-37

APPENDIXES. . 38-39

viii
 LIST OF FIGURES

Figure 1 : A piezoelectric disks generate voltage when deformed. . •7

Figure 2 : Energy Generating Floor System.. .8

Figure 3 : Piezo Transducers Concept .8

Figure 4 : Phases in Piezo Generator. .12

Figure 5 : Aluminium Dimensions . .14

Figure 6 : Piezoelectric and The Beam .15

Figure 7 : Full Bridge Rectifier Circuit. .15

Figure 8 : The Booster Circuit. .16

Figure 9 Work bench.. .18

Figure 10: The Prototype. .19

Figure 11 : The prototype With the FUll Wave Bridge Rectifier Circuit. .19

Figure 12 : The Full Wave Bridge Rectifier Circuit.. .20

Figure 13 : Output from Capacitor to The Battery. .20

Figure 14: Battery to the Circuit Booster. . .21

Figure 15 : The Prototype with the Full Circuit.. .21

Figure 16 : Voltage V s Time.. .24

Figure 17 : Current Vs Time .. .24

Figure 18: Voltage vs Time.. .27

Figure 19: Current vs Time.. .27

Figure 20 : Schematic Flow Diagram. .28

ix
Figure 21: Voltage Vs Time .. .29

Figure 22: Current Vs Time .. .29

X
 LIST OF TABLES

Table I : Material and Description. 13

Table 2 : Jobs Parts and Software. 13

Table 3 : Result from Experiment I. . 22-23

Table 4: Result from Experiment 2•. 25-26

xi
 CHAPTER!

INTRODUCTION

1.1 Background of Study

In Malaysia, the main activity in generating electricity is using the non·

renewable energy sources which are fuels and gases. This acitivity actually
produce a lot of carbon dioxide that will increase the concentrations of greenhouse
gases and will lead to the global warming. Moreover, the decreasing in these fuels
and gases had prompted the world to find another alternatives energy sources.
Thus, piezoelectricity is one of the alternative energy that will guarantee the
'green' energy.

The waste vibration energy needs to convert by using piezoelectric

generator and store as electrical energy in a battery. The battery will function as a
backup power supply for the charger when the piezoelectric generator cannot
produce any electrical energy. All this is based on principle of piezoelectric that is
direct effect, which can be converted from strain, mechanical or vibration energy
to electrical energy. The source of vibration will be taken from any moving
objects. In conjuction with that, motorcycle has been chosen to be the vibration
source.

Piezoelectric have many attractive features, such as not produce any

emission and have a high voltage. The circuit for this project will be designed to
boost and control the output voltage and current. Prototype for this project will be
specially designed to protect from damage due to high vibration, have high
efficiency to absorb vibration from any moving objects and make this innovation
portable to bring anywhere.

1
 1.2 Problem Statement

Nowadays, in a rapid growth world, there are more fuel and gas burning in
order to produce electricity. This is due to the increasing numbers of electrical
appliances around the world. These non-renewable energy sources are decreasing
rapidly and the world needs other alternatives energy sources. The piezoelectric is
one of alternatives energy sources. This energy can be generated from any sources
of vibration. One of the source of vibration is motorcycle. Every motorcycle
always produce vibration on the road. This vibration is actually a kind of energy
which we called as motion energy. So, instead of losing this energy for nothing,
this energy actually can be converted to an electrical energy using the
piezoelectric components. The piezoelectric energy has been used to generate
simple electricity to power microelectronic device such as mosfet and power
electronics equipments. However, the piezoelectric is not being used for any
vehicles yet. Due to small voltage produced, the piezoelectric only be used for
small applications only. This project will research on the power produced by the
piezoelectric effect and develop an application that can be used to transfer the
vibration from motorcycle to electrical energy.

1.3 Objective

Objectives of this project are as following:-

i. To identifY the piezoelectric effect.

ii. To identifY the behaviour of the voltage and current produced by the
piezolectric effect.
iii. To develop a piezoelectric generator to generate electricity from vibration.

2
 1.4 Scope of Study

This project required study from two aspects. First is to study the
characteristics, concept and the effect of the piezoelectric. The behaviour of the
voltage and current produced by the piezoelectric element will be emphasize in
this project. Next, is to measure the sensivity of the piezoelectric element. This
measurement will analyse the piezoelectric element weather the vibration from a
motorcycle is enough to cause the piezoelectric to produce voltage and current.
Both of this study then will be combined to produce a piezogenerator.

3
 CHAPTER2

LITERATURE REVIEW

2.0 Introduction

Piezoelectricity is the ability of certain crystals to generate a voltage in

response to applied mechanical stress. The word is derived from the Greek
piezein, which means to squeeze or press, The effect is reversible; piezoelectric
crystals, subject to an externally applied voltage, can change shape by a small
amount. The effect is of the order of nanometers, but nevertheless finds useful
applications such as the production and detection of sound, generation of high
voltages, electronic frequency generation, and ultrafine focusing of optical
assemblies [1].

2.1 Fundamentals and Theory of Piezoelectric

The piezoelectric effect is understood as the linear electromechanical

interaction between the mechanical and the electrical state in crystalline materials
with no inversion symmetry. The piezoelectric effect is a reversible process in that
materials exhibiting the direct piezoelectric effect. Piezoelectricity is found in
useful applications such as the production and detection of sound, generation of
high voltages, electronic frequency generation, microbalances, and ultra fine
focusing of optical assemblies. Piezoelectricity is the combined effect of the
electrical behaviour of the material using [2]:

D=eE (1)

Where D is the electric charge density displacement (electric

displacement), E is permittivity and E is electric field strength,and using Hooke's
Law:

S = sT (2)

4
 Where S is strain, s is compliance artd T is stress. These equations may be
combined into so-called coupled equations, of which the strain-charge form is:

{5} = [sE]{T} + [d'](E) (3)

(D} = [d]{T} t [E']{E} (4)

Where [d] is the matrix for the direct piezoelectric effect and [dt] is the
matrix for the converse piezoelectric effect. The superscript E indicates a zero, or
constant, electric field; the superscript T indicates a zero, or constant, stress field;
and the superscript t stands for transposition of a matrix.

The strain-charge for a material of the 4mm (C4v) crystal class (such as a
poled piezoelectric ceramic such as tetragonal PZT or BaTi03) as well as the
6mm crystal class may also be written as (ANSI IEEE 176):

•
•sil sf1 sfl 0 0 0 0
c
::1s,s, sf, sf:
(;:lr• .,. (:o '~~~") (!;)
SE 0 0 0
= ~J. ~t. "'
£i~ c 0 0 T, . 0 0
(5)
) 0 0 s£. 0 0 d:-4
s, I ) 0 0 0 s~ 0 Ts d 15 0 0 -
,; \ J u {) c u si6 =l1~sf1 - .sfz) '·T~:~-' 0 0 o·

(\ cD"
n;)
'= 0
du
0
0
d:n
0
0
dsg 0
0
d-;14
d,
0
0 ~(f}cr
0
E:;;::
0
I)
0
~ia/
)('1
E I
2
.EjJ
(6)

where the first equation represents the relationship for the converse
piezoelectric effect and the latter for the direct piezoelectric effect.

5
 In total, there are 4 piezoelectric coefficients, dij, eij, g~j, and hij defmed as
follows:

d E T (7)
"=
L)
(8Dt.)
8T·
= (8Di)
aT·
J J

, t )E=- (iJ'l'·
e£). . = (iJU· _l )s {8)

8Sj 8Ej

, )E _
g .. __ {8Ei (8St.)·T (9)
•1 I ar- aD
' J ].

(10)
h··= -(8Et)1J =- (8Tt_)s
L] 8S · 8D ·
' J J

Where the first set of 4 terms correspond to the direct piezoelectric effect
and the second set of 4 terms corresponds to the converse piezoelectric effect [3].

The conversion of mechanical energy into electrical can be generally

achieved by converters alternator types or commonly known as dynamo. But, the
piezoelectricity also can be used to transform the mechanical energy to electril:al
energy. The piezoelectricity used another type of conversion, which are from
vibtation or mechanical strain.

Basically, the piezoelectric effucts exist in two ways, which are the first
one is the direct piezoelectric effect and the other one is the reverse effect. The
direct effect describes the material's ability to transform mechanical strain into
electrical charge. This direct effect can be used as a sensor. Meanwhile, the
reverse effect is the ability of the material to convert an applied electrical potential
into mechanical strain energy. The application of the reverse effect is an actuator.
Figure 1 shows a piezoelectric disk generates voltage when deformed.

6
 Figure I : A piezoelectric disk generates a voltage when deformed (change in
shape is greatly exaggerated) [4]

2.2 Piezoelectric Generator Principle

The type of energy harvesting in this project is using the vibration source.
The vibration source can be found at any movement and this project will take the
source of vibration from the motorcycle. A motorcycle produces a constant level
of vibration and therefore it can be used to convert to electrical energy using the
piezoelectric element. The conversion will start from a mechanical energy source,
which is motorcycle. The motorcycle vibrations will be converted into electricity
through piezoelectric element. Then, the electricity produced will be converted
before supplying a storage system or the load. The piezoelectric has been used in
many wide applications.

The most popular application of this piezoelectric is in one of the subway

in Japan, where they invented the new piezoelectric energy generating floor. The
system will harvest the kinetic energy generated by crowds to power ticket gates
and display systems [5). This system use the piezoelectric element as the floor,
thus when they are crowd stepping on this floor will generate an electricity as
shown in Figure 2.

7
 Figure 2: Energy Generating Floor System [6]

The next application of this piezoelectric is to detect sound, e.g.

piezoelectric microphones (sound waves bend the piezoelectric material, creating
a changing voltage) and piezoelectric pickups for electrically amplified guitars. A
piezo sensor attached to the body of an instrument is known as a contact
microphone (7].

Piezoelectric materials are also being used as ultrasonic transducers for

medical purposes, and for industrial nondestructive testing, or NDT. The
transducer can act as both a sensor and an actuator. Ultrasonic transducers can
inject ultrasound waves into the body, receive the returned wave, and convert it to
an electrical signal (a voltage). Most medical ultrasound transducers are
piezoelectric [8]. Figure 3 shows how the piezoceramic can be used as
transducers.

Electncal t unent On

Figure 3 : Piezo Tranducers Concept [9]

8
 2.3 Motorcycle Vibration

A study about motorcycle vibration has been made through around the
world. The main objective of this study is to analyze the hazard that result from
this vibration. Motorcycle vibration was studied to evaluate riding comfort and
safety in terms of handling and stability. Since this project is about to harvest
energy from motorcycle vibration, so it is very crucial to know how strong the
vibration produced by the motorcycle. A research done by Motormu Y okomori,
Takeo Nakagawa and Tadao Matsumoto show that motorcycle actually has many
sources of vibrations [10]. the study stated that motorcylce vibrations are coming
from the motorcycle itself; posture of the hands and arms during the gripping of
the handlebars, the surrounding environment, and the period of time during which
the motorcycle is ridden.

According to the study, vibration is transmitted from the motorcycle along

the following three paths which are from the :-

• handlebarS to the hand-artrts and the body

• saddle to the buttocks,the waist, and the body

• foot ot the feet, the legs and the body

This study also stated that the vibration of the handlebars is caused by the
engine vibration, the roughness of the road, and the vibration of the frame and the
chasis. This shows that there ar~e actually many sources that cause the motorcycle
vibration. Thus, there are a bright future that these vibrations can actually produce
enough to give the piezoelectric works.

9
2.4 Vibration to Electrical Energy Conversion

The vibration to electrical energy conversion is now used average in the

world. This is because it is hard to find a constant type of vibration, especially in
environment that can produce vibration. Unlike other source such as wind, waves,
these can be found easily in our environment. The most popular invention of
vibration to electrical energy is the Power Micro-Electro-Mechanical System
(MEMS) which is a capacitive vibration to electrical energy converter with built-
in voltage. This design actually makes a parallelcplate electrostatic spring mass
system. The charging of the parallel-plate capacitor takes by utilizing materials
with different works functions for the electrodes. The Micro-Electro-Mechanical
System (MEMS) based capacitive energy is able to provide an output power of
4.28uW at an external vibration with a frequency of I kHz and an amplitude of
1.96m/s (0.2g). [11]

From this study, it shows that a conversion of vibration to electrical really

produce only a small amount of power. But this invention actually not use
piezoelectric element in the product. It is using the parallel·plate electrostatics to
produce the voltage.

10
 CHAPTER3

METHODOLOGY

3.1 Phases in Piezo Generator

There are four phases involved in this project. Ea.:;h one of the phase will
be achieved step by step.

3.1.1 Phase I

This is the first stage of this project which is to identify the piezoelectric
concept. The action to be taken in this stage is to do a deep research on how the
piezoelectric works. A part from that, the situational analysis is essential to do in
order to identify the piezoelectric concept.

3.1.2 Phase 2

The second stage in this project is to identify the measurement criteria for
evaluating the produce current and voltage by the piezoelectric element. At this
stage, a thorough search will be made via internet and from the library to collect
all available information on the measuring knowledge. The collections of the
technical report regarding the subject matter in the world are essential in order to
identifY the common criteria on measuring the current and voltage. The major
deliverable for this stage is the criteria on measuring the produced current and
voltage from the piezoelectric element. A part from that, the formula of
converting from the vibration to current and voltage will be achieved at this stage.

11
 3.1.3 Phase 3

To develop a energy converter from vibration is the third stage of this

project. An agile methodology for developing the converter is adopted in this
pbase. This is to redl.!ce time as well as to ensure the tool developed is parallel
with the user requirements. The major deliverable for this stage is the completion
of energy generator called Piezogenerator.

3.1.4 Phase 4

The final stage for this project is the implementation and user testing on
the system. This system is test in the lab. Figure 4 shows the full phases in this
project.

Phase 1:

Identify the Testing a Develop a Implement and

piezoelectric piezoelectric pretotype to testing the
co!ICt:pt element prototype on a
motorcycle

Figure 4 : Phases in Piezo Generator

12
3.2 Identification of Appropriate Hardware and Software

Table I and Table 2 show the list of suitable hardware, tools and software
that are being used in this project.

Table 1 : Material and Description

Material Description
·~··--·" --· - -·· -·-
Piezoelectric Bi- Crystal element that generates voltage when being stress or
Morph Sensor strain (vibration)

Amplifier, rectifier, stabilized and boost the electricity

Electronic circllit
generated

Zil!.c Material to be used as a beam due to low elastic modulus.

~- ·---------~--~----··-~----- ----------~ ------ ---------- - ------~-·--
---------·--------- --- ---- -·----·--- ----- - ------------
Aluminium To be used as the base of the prototype

DC Motor Use to generate vibration.

Table 2 : Jobs Parts and Software

Part Software

Diawiiig AiitoCAD

Documentation Microsoft Word 2003 & :2067

Electrical Circuit PSPICE, Pasco Data Studio

13
3.3 Construct the Base ofthe Generator

This project is using aluminium plate to make the permanent flat surface.
This is the base structure of the piezoelectric generator. Aluminium is used
because it has a solid structure. So that, it can transfer the vibration more to the
piezoelectric elements. Cutting machine is used to cut the aluminium plate to the
desired dimension. Figure 5 illustrates the dimension.

!~

lOcm
~~I
Figure 5 : Aluminium Dimension

3.4 Construct the Beam and the Piezoelectric Element

Basically, the beam that is used as the cantilever is using the Zinc plate.
The Zinc has lower elastic modulus value that makes it less stiff than other metals
materials. Thus, it can produce more vibration. The piezoelectric element will be
glued using epoxy on the beam. Figure 6 shows how it is glued.

14
 ~r==::;;;;:=:::;;::;;:::;:;;:;:;:;=:;:;Dfll I Piezoelectric element

Glue using epoxy

Zinc

Figure 6 : Piezoelectric and The Beam

3.5 Electric Circuit

3.5. 1 Full Bridge Rectifier Circuit

The voltage produced using piezoelectric element is in AC form. In other

words, it is in sinusoidal wave. Therefore, in order to use for mobile charger, it
needs to be converted into DC form. This is because; the mobile charger is using
the DC voltage. Schottky diodes are used in this rectifier circuit as they have very
minimum voltage drop, which is around 0.7 V. As to regulate the voltage, a IJ.1
Farad capacitor is placed at the output of the circuit. The capacitor also will be
used to charge battery when it receives energy. Figure 7 shows the diagram of the
full bridge rectifier used.

ACin

Battery

Figure 7: Full Bridge Rectifier Circuit

15
 3.5.2 Booster CitCilit

The booster circuit is constructed using LT1073. This circuit is a micro

power DC/DC converter that be used as a step-up or step-down converter. In this
project, it is basically being used to step up 2.5 v of voltage that was produced by
the battery to achieve 5 V of output. When the switch is ON, the diode will be
reversed biased, and will isolate the output stage. Then, the input will supply
energy to the inductor. When the switch is OFF, the output stage will receive
energy from the inductor as well as from the input.

The output filter capacitor is assumed to be very huge to ensure a constant

output voltage when in the steady-state analysis. The oscillator is then set
internally for 38 ms ON time and ISms OFF time, and thus optimizing the device
to step-up circuits where VoUT » 2 V1N, e.g, 2.5 V to 5 V.

:::~/,:r:-. ~M.1~~v~
:"T!=\To·

R2.
R1. ll09k
6801< ""TEXT>-
J2 2IEXT>- J1
C1
· 100uF
MAX1724EZK50 · <TEXT->
!)Q9st oo~~r IC
R3.
40,2k-
4EX-T>

Figure 8 : The Booster Circuit

16
 CHAPTER4

RESULTS AND DISCUSSIONS

4.1 Develop Work Bench for Piezo Generator

In order to test the piezoeleactric element, a work bench has been designed
which can be used to check the behaviour of the voltage and current produced by
this element. Actually, the work bench is almost the same with the prototype. The
only different is that the work bench has many different cantilever beams, so that
they can be tested using various experiment. This work bench is made for analyze
on how much exactly the voltage can be produced by a certain level of vibration.
This experiment is very crucial for this project because it will justizy wether the
vibration from the motorcylce can be used to make the piezo element to generate
electricity or not.

The piezo element used for this experiment is the Piezoelectric Bi-Morph
type. The testing tool is made up from zinc, aluminium, bolts and nuts. Basically,
the zinc is used as the beam which the piezo will be placed on it, and the
aluminium is used as the base for beam. There are several conditons that lead the
chosen of zinc as the beam. The zinc has lower Elastic Modulus than the
aluminium. The Elastic Modulus describes the mathematical description of an
object subrtances's tendency to be deformed elastically when a force is applied to
it [12]. According to the Static Properties of Materials under Standard Conditions
(approximately 20), the elastic modulus for aluminium is 72( 10) N/m meanwhile
forthezincis 13.1(10)N/m [13].

There is a huge difference between the value. The higher the elastic
modulus value, the stiffer the material. So that, by this condition, the zinc will be
used as the beam, as it will be more sensitive to any kind of vibration and it is
easy to capture the vibration. Figure 9 shows the work bench of the piezo
generator.

17
 Springhead
Piezoelectric
Nail
Zinc Beam

Aluminium
1 J
Box

.--A-Iu_m_i-ni_u_m----,1/

Figure 9 : Work Bench

The piezo element is glued on the beam and the beam will be placed on the
aluminium box. The position of the beam and piezo element will be at 20 percent
from the aluminium box. This is to ensure that when the beam start to oscillate,
the piezo element will get easy to be bend. Next, the whole thing is placed on a
piece of zinc surface. This zinc will be the medium for the vibration source to
move. As a de motor will be placed soon on this surface, it will generate a
vibration and hence the surface will receive the vibration and transfered to the
work bench. This work bench will be used for the experiment in order to
determine how much voltage and currrent actually this piezoelectric element can
produce due to vibration.

18
 4.2 Prototype and Circuit Fabrication

The prototype has been designed using autoCAD software. The prototype
is designed so that it can be put on motorcycle handlebar and anywhere that has
vibration source. Below are the figures of the prototype and the circuit used.

Figure 10 : The Prototype

Figure 10 shows the piezoelectric element with the base and the cantilever
beam. While in Figure 1 I, shows the piezoelectric element connected with the full
wave bridge rectifier circuit.

Figure 11 : The prototype with the Full Wave Bridge Rectifier Circuit

19
 ln Figure 12, shows the full wave rectifier circuit, which consists of
Schottky 4 diodes, a 1kO resistor and 1J.lF capacitor. In Figure 13 shows the
output from the rectifier circuit connected with the battery and then to the booster
circuit.

Figure 12 : The Full Wave Bridge Rectifier Circuit

Figure 13 : Output from Capacitor to The Battery

20
 Figure 14 shows the battery is connected with the circuit booster, while in
Figure 15 shows the full prototype with the full circuit.

Figure L4: Battery to the Circuit Booster

Figure 15 : The Prototype with the Full Circuit

21
 4.2 Results of Experiment

The work bench is then tested using Pasco Data Studio Software. This
software can be used to tested voltage and current, and frequency for this work
bench. The motor used for the experiment is a DC motor which will cause
vibration to the work bench when it turn on. As for the result, an AC voltage and
current are produced. Three different experiments are conducted in this stage,
which are the first one using DC motor as the source of vibration, the second
experiment is using manual vibration, and the third experiment will be using with
the full circuit of converter and booster to test the prototype. The voltage
produced is the RMS voltage. In all three experiments, there are two piezoelectric
element that has been tested with series connection.

4.2.1 DC Motor Experiment

For the first experiment, a DC motor is used for the source of vibration. A
12V DC motor with 50 Hz of frequency has been tested for this experiment. This
experiment only use 2 piezoelectric elements to be tested. This is to determine
how much actually the voltage and current can be produced with vibration. The
frequency of the vibration in this experiment is around 32 Hz. The result of this
experiment is tabulated in Table 3. For the sake of analysis, the tabulated data in
Table 3 is converted in graph figure as shown in Figure 16 and Figure 17.

Table 3 : Result from Experiment I

Time (Sec) Voltage (V) Time(Sec) Current (A)

0 -2.3378 0 -0.00000354
!l.l ...... . -O.IJ6 . 0.1 -0.00000452
0.2 1.7435 0.2 0.00000513
0.3 2.2397 0.3 0.00000458
0.4 O.i664 0.4 0.00000446
0.5 -2.471 0.5 -0.00000494
0.6 -0.2985 0.6 -0.00000543
0.7 2.1358 0.7 0.00000525

22
0;8 0.2462 0;8 0.00000347
0.9 -2.8358 0.9 -0.00000494
1.0 0.2734 I 0.00000525
1.1 1.7435 1.1 0.00000488
1.2 2.2397 1.2 0.00000494
1.3 0.1634 1.3 0.00000494
1.4 -2.371 1.4 -0.00000513
1.5 -0.2995 1.5 -0.00000494
1.6 2.1458 1.6 0.00000482
1.7 0.2362 1.7 0.00000482
!.8 -2.8558 1.8 -0.00000488
1.9 0.2704 1.9 0.00000482
2.0 1.7335 2 0.00000161
2.1 2.2297 2.1 0.00000447
2.2 0.1654 2.2 0.00000488
2.3 -2.471 2.3 -0.00000574
2.4 -0.2985 2.4 -0.00000813
2.5 2.1458 2.5 0.00000387
2.6 0.2362 2.6 0.00000456
2.7 -2.8358 2;7 -0;00000635
2.8 0.2704 2.8 0.00000484
2.9 1.7335 2.9 0.00000399
3.0 2.3297 3 0.00000511
3.1 0.1654 3.1 0.00000171
3.2 -2.471 3.2 -0.00000446
3.3 -0.2985 3.3 -0.00000418
3.4 2.1358 3.4 0.00000165
3.5 0.2362 3.5 0.00000551
3.6 -2.8457 3.6 -0.00000846
3.7 0.2704 3.7 0.00000177
3.8 1.7335 3.8 0.00000251
3.9 2.2'297 3.9 0.00000304
4.0 0.1654 4 0.00000415
4.1 -2.471 4.1 -0.00000476
4.2 -0.2985 4.2 -0.00000584
4.3 2.1358 4.3 0.00000599
4.4 0.2362 4.4 0.00000655
. ·- ___
4.5 .. - ----- -··-·
:z:s458
,
. '4.5 . -=llJTOUOU53T
4.6 0.2704 4.6 0.00000244

23
 Volt~ge vs Time
3
Voltage IV)
2
1
0 Time (Sec)
-1 0 2 3 5

-2

-3
-4 -Voltage

Figure 16: Voltage vs Time

r----------·-----------------------~-------------~-----------·-------------------·----,

i! Current (A)
current Vs Time I
1 0.00001
0.000008
0.000006
0.000004
0.000002
0
-0.00000 2 3 . --5 Time (Sec)
-0.00000
-0.00000 --Current (A)
I -0.00000
L-o.oooo1

Figure 17: Current vs Time

24
 4.2.2 Manual Vibration Experiment

In the second experiment, another type of movement is used.A human

finger has been used as the source of vibration which mean that the finger is used
to produce the vibration. In this experiment also, only 2 piezoelectric elements
only will be tested. No external circuit is used. The frequency is around 28 Hz
until 54 Hz. The result of this experiment is tabulated in Table 4. For the sake of
analysis, the tabulated data in Table 4 is converted in graph figure as shown in
Figure 18 and Figure 19.

Table 4: Result of Experiment 2

Time (Sec) Voltage(V) Time(Sec) Current (A)

10 0.9223 10 0.00000355
10.1 0.1251 10.1 0.00000461
10.2 -0.3674 10.2 -0.00000512
10.3 0.976 10.3 0.00000433
10.4 -3.1892 10.4 -0.00000432
10.5 2.4494 10.5 0.00000454
10.6
- .
0.1508 10.6 0.00000565
10.7 ·0.2649 10.7 ·0.00000567
10.8 1.6175 10.8 0.00000334
10.9 0.1459 10.9 0.00000456
II -0.6397 II -0.00000576
11.1 0.1886 11.1 0.00000444
11.2 -0.445 11.2 -0.00000496
11.3 1.3971 11.3 0.00000493
11.4 0.1953 11.4 0.00000523
11.5 -2.4378 11.5 -0.00000454
11.6 '0.116 11.6 -0.00000476
11.7 1.7335 11.7 0.00000482
11.8 2.2297 11.8 0.00000486
11.9 0.1654 11.9 0.00000443
12 -1.4'71 12 -0.00000465
12.1 -0.2985 12.1 -0.00000465
12.2 6.1458 12.2 0.00000499
12.3 0.2362 12.3 0.00000512
12.4 -1;8458 12.4 -0.00000832
12.5 0.2704 12.5 0.00000355
12.6 ·10 12.6 ·0.00000478

25
12;7 03638 123 0.00000634
12.8 -1.2336 12.8 -0.00000483
12.9 1.4972 12.9 0.00000398
13 -0.6775 13 -0.00000522
13.1 0.2411 13.1 0.00000176
13.2 -3.44!9 13.2 -0.00000435
13.3 0.9265 13.3 0.00000419
13.4 -0.7477 13.4 -0.00000165
13.5 4.3214 13.5 0.00000551
13.6 0.2094 13.6 0.00000876
13.7 -1.8201 13.7 -0.00000156
13.8 0.0385 13.8 0.00000251
13.9 2.2761 13.9 0.00000355
14 -2.3536 14 -0.00000478
14.1 1.8616 14.1 0.00000444
14.2 0.4718 14.2 0.00000567
14.3 -0.0897 14.3 -0.00000588
14.4 0.2258 14.4 0.00000644
14.5 -0.2063 14.5 -0.00000563
14.6 0.4407 14.6 0.00000223

26
 Voltage (V)

4
2
0
-2 0 2 4 6 8 16 -Voltage(V)
-4 Time (sec)
-6
-8
-10
-12

Figure 18: Voltage vs Time

r·-----···-- ····-------------·-··---··--·------·---·----- ---------- ---·-------------- ------·-- -···---- --------··----------,
Current Vs Time
.
1,
Current (A)
0.00001
0.000008
0.000006
0.000004
0.000002
0
-0.00000 0- - ... -. --5 5- - -- ----20 Time (Sec)
-0.00000
-0.00000
-0.00000
--Current (I) j
-0.00001
[ _ _ _ _ _ _ __

Figure 19: Current vs Time

27
 4.2. 3 DC Motor and Prototype experiment

This is the final experiment that determine the full result of this portable
piezoelectric generator. In this experiment, the full prototype, will be tested on a
de motor at frequency of 32 Hz. Figure 20 shows of how this piezoelectric
generator actually produce electricity in this experiment.

DC Motor Produce
vibr~ti()n v.-hE!n moving,

Jl
The vibration will vibrate
the piezoelectric
generator.

J.l
When vibrate, the
ph~zseleGtriG Will Greate
voltage and current.

J.l
Electricity produced and
will be fed on a charging
circuit.
·- --
:cr~
~·

The charging circuit will

store energy until
maximum.

J__L
When fully charged, the
energy will be usei:l to
charge handphone.

Figure 20 : Schematic Flow Diagram

28
 In this experiment, an empty ot discharged capacitor is used to be charged.
This capacitor actually represent the battery and will determine the whether the
voltage and current produced is enough to charge capacitor or not. Figures 21 and
22 below show the result of the graph obtained from this experiment. Due to long
data, the table will not be included in this report.

__________,.._, _______________________ --------------- ----------1

Volt~ge Vs Time
3.00E+OO i
Z.SOE+OO !

2.00[+00

L50E·t00
I
LOOE+OO -
_ ,. .,.", I

5.00E-01

0.00[+00

0 20 40 60 80 100
-S.OOE-01
I
Figure 21: Voltage Vs Time

~----------~urr~~~ ~s Time
I 0.000003 -- - · -· - --

1 0.0000025 -- -

I o.ooooo2 -:--
1 0.0000015 -

I o.ooooo1
1 o.oooooo5
-Current (A)
I o
0 40 60 80 100
-SE-07
I I

Figure 22: Current Vs Time

29
 4.3 Discussion

4.3.1 K--cperiment I & 2

From experiments 1 and 2, the voltage produced is quite high. Using the
DC motor, the voltage produced is approximately at constant 2 V. This value is
actually the value of two piezoelectric elements which means that 2 V is the value
of total voltage when the piezoelectric is put in series connection. Indeed, this
voltage can go more higher than that because from the manual experiment, the
voltage can reach until 10 V. It shows that the voltage produced is basically
depends on how much the piezo element can vibrate. The more vibration it gets,
the higher the voltage can produce. The target for this project is to ensure that the
voltage 11nd current produced can be used directly to charge at least a cellular
phone. For that purpose, the required voltage and current needed is 5V at I OOmA.

As for the current, from both experiments, the value of the current is very
low. The value of the current can be said vary from 0.000001 A until 0.000008 A.
This is equal to 1!!A until 811A. This value is too low for any direct applications.
This is because of the piezoelectric does not produce high current Due to the very
low current is the reason why it still cannot be used to generate a large scale of
electricity such as solar and hydro. So, the current produced is not enough to
charge a cellular phone. Theoretically, to charge a cellular phone, the current
required is at least around 100 rnA. From both experiments, it can be concluded
that the piezoelectric do produce high voltage but very low current value. Thus,
the piezoelectric cannot be directly used to charge a cellular phone without any
external circuit. Due to this situation, the generator will be used to store energy
first. This is demonstrated by charging a capacitor.

30
 4.3.2 Experiment 3

As for the third experiment, which is using the prototype and the full
circuit, it can be seen that the graph produced is actually in charging mode. When
the piezoelectric starts to vibrate, the voltage produce is ar.ound 2.2 V. But when it
pass through the rectifier circuit, there is voltage drop occur. This is because the
the diodes actually have internal resistance, and thus have voltage drop. When
measured at the bridge output, the reading is around 0.74 V. But at the input, the
reading is 2.1 V. When the value from the input minus the value from the output,
it gives 1.36 V. This 1.36 Vis actually the voltage drop in the circuit. So that 0.74
V is the l!(:rual O\ltp\lt valm: from the bridge circuit. As for the C\lrrent, the vallle is
still the same, which is around 4uA. Then when it pass through the capacitor of 11!
Farad, the graph produce a charging graph. This shown that the voltage and the
current produced is actually enough to charge the battery.

From the graph, the graph is increased and when the capacitor has been
fully charged, the graph will decrease because it will discharge. The process of
charge and discharge is so fast because the value of the capacitance used is small,
which is l!!F. When lower value of capacitance is used, it will charge and
discharge very fast, because it cannot hold the charge for longer time. The reason
for using lower value of capacitance is because to prove that the voltage and
current produced is enough to charge the capacitor. Bigger capacitor value such as
1 Farad can be used iii this experiment, but it requites longer time to show the
charging graph. Because when the capacitor is bigger, the time taken to charge the
capacitor become longer and thus the graph obtained will be slow.

The graph produced is not consistently increase. This is because in order to

charge the capacitor, a the current and voltage must be at steady state. However,
because of this experiment cannot give a stable voltage and current, due to the
vibration, it will not charge the capacitor steadily. Thus, as can be seen in Figure
21, the graph will not steadily increase. This experiment has shown that the
voltage and current produced enough to charge the capacitor.

31
 4.3.3 Justification ofResult

From all experiments, it can be seen that the current produced is not
enough to directly charge a cellular phone. This is because the current is too small
and not sufficent, even to light up a single LED. Because of this situation, the
current and voltage produced will be stored first in a battery. This is done by
looking at the third experiment, the values are enough to at least charge a
capacitor. The graph in experiment 3 shows that the voltage and current actually
has charged the capacitor, although it is not charging consistently due to the
inconsistent of vibration. The charging time will depend on the value of the
current supply. The bigger the value of the current, the faster it will charge and
thus will result in less time to charge. Meanwhile, if the current is very smail, then
it takes longer time to charge. The energy stored in the capacitor will then be used
to charge acellular phone or other electronic devies. The average output from the
piezogenerator is given below:

P=IV (11)

Where P is the power, I is the current and V is the voltage. Taking average
voltage of0.74V and 5uA, substitute in the above equation gives:

P = 5uA x 0.74V

= 3.7uW

Based on this result, the power will be stored first in a battery, and then the
battery will be used for other purposes. As for the efficiency is calculated below:

(12)

=24.67%

32
 The result of efficiency is very low and can be considered as not efficient
enough. There are several factors that cause the low performance of this
piezoelectric generator. The first one is because the it produce large voltage but
with an extremely low current. When current low, it will affect the performance of
the generator. Another reason is because the power is dissipated by electronic
devices such as diodes, which will resulting in lower efficiency. From overal
experiment, it can be said that the generator is able to charge the capacitor.

33
 CHAPTERS

CONCLUSION AND RECOMMENDATIONS

5.1 Conclusion

As a conclusion, this project has actually succeed in all objectives that

have been stated in the early of this report. This project use the piezoelectric effect
theory, which produce electricity form the vibration energy. From this project, the
vibration generated from the motorcycle will be used as the main source to
generate electricity using piezoelectric element. This piezoelectric generator is
portable, thus it can be used anywhere as long as there are sources of vibration.

The portable piezoelectric generator cannot directly charge a celhilar

phone the vibration because of low current. Then, it has been modified to be used
as battery charger, which has been demonstrated by charging a capacitor. The
piezoelectric generator will store energy in a battery, and then when the battery is
fully charged, it will be used to charge a cellular phone. This project is considered
as green technology since it produces no emission and thus it is environmentally
friendly.

34
 5.2 Recommendations

Improvising this project by adding some new features or functions is an

effective ways to utilized the waste energy as well as saving the cost of producing
electricity. Until now, the piezoelectric still cannot produce electrical energy for
large usage due to lack of current. In our market today, there are still no electrical
generator that use piezoelectric. The only thing available that use piezoelectric is
such as buzzer, and speaker which is not being use to generate electricity.

In the future, a bigger size of piezoelectric sensor will be used in order to

test output voltage and current. A current booster circuit will be designed so that
the output current can be used to charge a cellular phone.

35
 REFERENCES

[I] The Piezoelectricity

<http://www.spiritus-temporis.com/piezoelectricity/applications.html>

[2] , (I)- (I 0) Piezoelectricity

<http://en.wikipedia.org/wiki/Piezoelectricity>

[3], (I)- (10) Piezoelectricity

<http://en. wikipedia.org/wiki/Piezoelectricity>

[4] Piezoelectricity

<http://en. wikipedia.org!wiki!Piezoelectricity>

[5] Jorge Chapa, 2008, Energy Generating Floors to Power Tokyo Subways

<http://www.inhabitat.com/2008/12/ll/tokyo-subway-stations-get-
piezoelectric-floors/>

[6] Envirothink, December 12, 2008, Human Energy Powers Japanese

Subway Station

<http://envirothink.wordpress.com/2008/12/12/human-energy-powers-
japanese-subway-stationf>

[7] The Piezoelectricity

<http://www.spiritus-temporis.com/piezoelectricity/applications.htrnl>

[8] The Piezoelectricity

<http://www.spiritus-temporis.com/piezoelectricity/applications.html>

36
[9 ] Ingo Kuehne, Alexander Frey, Djordje Marinkovic, Gerald Eckstein and
Helmut Seidel, 7 March 2007, Power MEMS- A Capacitive Vibration to
Electrical Energy Converter With Built-in Voltage.

<http://www.sciencedirect.com >

[10) Motomu Yokomori, Takeo Nagakawa, and Tadao Matsumoto, 1986.

332-337

Handlebar Vibration of A Motorcycle During Operation On Difforent Road

Surfaces.

[ ll] Scott Meninger, Jose Oscar Mur-Miranda, Rajeevan Arnirtharajah,

Anantha P.Chandrakasan, and Jeffrey H.Lang, Fellow, IEEE, February 2001,
Vibration- t()- Electric Energy Conversion

[12] Elastic Modulus

<http://en.wikipedia.org/wiki/Elastic_modulus>

[13] Damping Properties of Materials Revision C by Tom Irvine, November

8,2004

37
APPENDIX

38
 Gantt Chart For FYP 2

No. Detail{ Week 1 2! 3 4 5 6 7 8 9 10. 11 12 13 14i

. .
. .

' 1 Design Current Booster

2 Testing.the circuit .·
'

3 Analysis ~
...a:
! .
ID
4 Submission of Progress Report a:
ti...
' 5 Submission of Draft Report .
' ...
:~:
. Ill
..

9
6 Submission of Technical Paper :i:

7 Submission of Final Report (soft copy) .··

8 VIVA
!

9 Submission of Final Report' (hard copy) '

D' Process

39