Generation of Electrical Energy Using Piezoelectric

Material from Train Wheels: Bangladesh Perspective

Md. Mostaqim Billah Arnab1*, Shah Md. Rahmot Anik Paul Mishu6
Ullah2, Md. Ashraful Alam3, Raton Kumar Nondy4, A BSS Associate Engineer
S M Forhadul Alam5 Operation and Maintenance Department
1, 2, 3, 4
Department of EEE Banglalink Digital Communication Limited
5
Department of Physics Narayanganj, Bangladesh.
1, 2, 3, 4, 5
University of Dhaka (Mymensingh Engineering
College) Mymensingh, Bangladesh.
*E-mail:arnab.mostaqim@gmail.com

Abstract—Scientists are desperately searching for renewable one of the most interesting methods of obtaining the energy
and green sources of energy to produce electrical power. In past surrounding a system is to use piezoelectric materials. This
several years, researchers have begun using piezoelectric technique utilizes piezoelectric components where
material for structural vibrations suppression. These materials deformations produced by different means are directly
transform mechanical energy to electrical energy and vice versa. converted to electrical charge via piezoelectric effect.
The objective of this paper is to present an effective method for Piezoelectric materials have a crystalline structure that
producing usable electrical energy from available sound energy provides a unique ability to convert an applied mechanical
from train wheels. We have observed that huge amount of sound strain into an electrical potential or vice versa. Our paper
energy is wasted in train movement (traction) System. In this includes how to utilize the energy which is wasted, creates
paper an approach has been made to make fruitful application of pollution to the environment. The sound energy of the moving
the wasted sound energy. The proposed conversion circuit was
train wheels which is nothing but pollution can be converted
tested in sound sources of train wheels and a comparison was
made between other sources using this conversion circuit and a
into electrical energy with the help of piezoelectric material or
better result from train wheels have observed. The output of transducer. Then this electrical energy will be saved with the
conversion circuit is around 12 volt which is sufficient to charge a help of a rechargeable DC source. This energy can be used to
rechargeable DC battery where a fully discharged 9 volt dc run a train compartment’s lights and fans and other necessary
battery was found to be fully charged within half an hour from purpose. Here we discover the technology to generate electric
transduced electric power. The proposed electric power supply power from sound of train wheels in which the system used is
can be used to run low power electrical equipments like light, fan reliable and this technique will help conserve our natural
etc. in train compartments. resources.
Keywords—Piezoelectric material, transducer, super capacitor,
train wheels, DC battery. II. PREVIOUS WORK
During the last decades, piezoelectric materials made huge
I. INTRODUCTION progress in entering commercial mass markets throughout all
At present in the universe the primary need for survival of branches, where piezoelectric are used as the basis materials
all organisms is energy. Everything what happens in the for actuators as well as sensors. Especially in transportation
surrounding is the expression of flow of energy in one of the industry, they found numerous fields of applications. The
forms. In this fast moving world small country like development of piezoelectric actuators for fuel injection
Bangladesh, where population is greater than its territory, systems is a popular application of the near past, active noise
there the current power generation has become insufficient to and vibration reduction is a current activity, and the use of
fulfill their demands. Therefore to overcome this problem we piezoelectric materials for energy harvesting in vibrating
need to implement the techniques of optimal utilization of structures is one possible future trend [1].
conventional sources for conservation of energy. At present, a
great deal of research effort has been directed to finding eco- The greatest untapped sources of piezo-electric energy are
friendly and renewable sources of energy. freeways and busy roads. If piezo-electric mats were installed
under the busiest sections [a little ways under the surface], the
Renewable energy sources such as hydropower, solar thousands of tons of vehicles passing over each day would
power and wind power require high financial investments but generate massive amounts of electricity for the city's use. The
give lower power output with respect to its cost. Another basis of this system is that they have unique abilities to harvest
source nuclear power plant gives a good source of power but energy from weight, motion, vibration and temperature
the initial setting up and maintains costs are higher than other changes. The energy generated from the moving vehicles is
renewable sources. In recent years, there has been growing stored in huge batteries and from the batteries the energy is
interest in harnessing the power of mechanical vibrations and used for the city’s energy consumption. This can be used for
pressure to generate electricity. Piezoelectric materials play a example to light the street lights at night from the entire
vital role in generating power which range is μW to mW. It is energy stored in the batteries. It can also be used for powering

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the household gadgets and in short the city as a whole saving interesting properties for the production of electricity,
lots of fuel used in electricity generation in an eco-friendly however artificial piezoelectric materials such as PZT (Lead
way [2]. Zirconate Titanate) present advantageous characteristics.
Piezoelectric materials belong to a larger class of materials
Health monitoring and damage detection concepts have called ferroelectrics. One of the defining traits of a
attracted many researches in the past [3] [4], especially with ferroelectric material is that the molecular structure is oriented
involvement of piezoelectric materials as the sensing elements such that the material exhibits a local charge separation,
[5]. Within the aforementioned project In Mar, a new known as an electric dipole. Throughout the artificial
development is under research. This is a wear detection piezoelectric material composition the electric dipoles are
system for train wheels. The idea is to detect the changes in orientated randomly, but when a very strong electric field is
the vibration behavior of the entire wheel caused by the applied, the electric dipoles reorient themselves relative to the
surface changes on the rolling contact area, Theoretical work Electric field; this process is termed poling. Once the electric
on the vibration behavior of train wheels encourage to choose field is extinguished, the dipoles maintain their orientation and
this kind of method [6]. Piezoelectric sensors are placed on the material is then said to be poled. After the poling process
distinct areas of the wheel, changing the displacements on the is completed, the material will exhibit the piezoelectric effect.
surface into electrical signals. The biggest problem is to
The mechanical and electrical behavior of a piezoelectric
adequately define the correlation between modal behavior of material can be modeled by two linearized constitutive
the wheel and the measured signals as well as the sensitivity of equations. These equations contain two mechanical and two
the overall concept to the comparably small changes in modal electrical variables. The direct effect and the converse effect
parameters. may be modeled by the following matrix equations: Direct
Researchers are also working on the idea of utilizing the Piezoelectric Effect: D = d.T + εT.E (1)
vibrations caused from the machines in the gym. At Converse Piezoelectric Effect: S = sE.T + dt.E (2) [9]
workplaces, while sitting on the chair, energy can be stored in
the batteries by laying piezoelectric crystals in the chair. Also,
the studies are being carried out to utilize the vibrations in a
vehicle, like at clutches, gears, seats, shock-ups, foot rests [7].
In Bangladesh, researchers are also working on the idea of
electrification of Streets of Dhaka City Using Solar and
Piezoelectric Energy [8].

III. WHAT IS PIEZO-ELECTRIC MATERIAL?

The word piezoelectricity means electricity resulting from
pressure. Piezoelectricity is the charge that accumulates in
certain solid materials stress. Piezoelectricity is the ability of
some materials (notably crystals and certain ceramics) to
generate an electrical potential in response to applied
mechanical stress. This may take the form of a separation of
electric charge across the crystal lattice. If the material is not
short circuited, the applied charge induces a voltage across the Fig. 1. Electromechanical conversion via piezoelectricity phenomenon.
material. The word is derived from the Greek word piezien,
which means to squeeze or press. The conversion of Where D is the electric displacement vector, T is the stress
mechanical energy into electrical one is generally achieved by vector, εT is the dielectric permittivity matrix at constant
converters alternator type or commonly known dynamo. But mechanical stress, sE is the matrix of compliance coefficients
there are other physical phenomena including piezoelectricity at constant electric field strength, S is the strain vector, d is the
that can also convert mechanical movements into electricity. piezoelectric constant matrix, and E is the electric field vector.
The phenomenon that produces an electric charge when a The subscript t stands for transposition of a matrix. When the
force is applied to piezoelectric material is known as the material is deformed or stressed an electric voltage can be
piezoelectric effect. The piezoelectric effect exists in two recovered along any surface of the material (via electrodes).
domains, the first is the direct piezoelectric effect that Therefore, the piezoelectric properties must contain a sign
describes the material’s ability to transform mechanical strain convention to facilitate this ability to recover electric potential.
into electrical charge, the second form is the converse effect, The piezoelectric effect is the process of internal generation of
which is the ability to convert an applied electrical potential electrical charge resulting from an applied mechanical force.
into mechanical strain energy figure 1. The direct piezoelectric The origin of the piezoelectric effect was, in general, clear
effect is responsible for the materials ability to function as a from the very beginning. The displacement of ions from their
sensor and the converse piezoelectric effect is accountable for equilibrium positions caused by a mechanical stress in crystals
its ability to function as an actuator. A material is deemed that lack a centre of symmetry must result in the generation of
piezoelectric when it has this ability to transform electrical an electric moment, i.e., in electric polarization. Attempts to
energy into mechanical strain energy, and likewise transform calculate the piezo constants of a crystal based on this model
mechanical strain energy into electrical charge. The were first undertaken by the brothers Curie as shown in
piezoelectric materials that exist naturally as quartz were not following figure 2.

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 signal is alternating. So, we need to amplify and rectify it to
get a reasonable output DC voltage which may charge a
rechargeable energy source.
In our proposed method, for conversion of sound energy
into electrical energy we used several piezoelectric
transducers. These transducers are taken from acoustic-electric
guitars because they are small. In our experiment, a small
buzzer of 6 volt, 2 KHz sinusoidal wave has used. The
resultant buzzer has worked as sound source and created about
200mV across those transducers which are in ac form. For
filtering, storing and prevent this ac voltage a 1 farad of 5.5
volt super capacitor has used. All super capacitors used in
parallel to the piezoelectric material. The super capacitor is
also known as Electrical Double Layer Capacitor (EDLC).
Super capacitors are differs from other general capacitors. It
can bridge the gap between capacitors and batteries with its
Fig. 2. Origin of piezoelectric effect and polarization.
high capacitance value. Super capacitors required short time to
charged, that’s why available sound energy can be easily
stored as electrical energy. But it needs much longer time to
IV. ADVANTAGE OF GENERATION OF ELECTRICITY USING discharge. So, the stored electrical energy can be hold for
PIEZO-ELECTRIC MATERIAL longer time than other capacitors.
• It could help us to reduce the scarcity of electrical
energy globally and help in the development of
mankind and reduction of CO2 as electric energy is
one of the cleanest energy.
• The noise pollution in the road would be able to
convert into electric energy and lights the street
lightning, signals and various other electrical
Appliances.
• Power generation with low cost and using non-
conventional energy sources which will help us to
conserve the conventional energy sources to meet the
future demand.
• By using this method, electricity will be generated
throughout the year without depending on other
factors.
• Easy for maintenance and no fuel transportation Fig. 3. Simulation circuit diagram of conversion from sound energy to
problem. Pollution free power generation. electrical energy.
• No need of manpower during power generation.
In our proposed method, sound energy generated from
• To store the electricity in DC rechargeable source. train wheels was used to produce small electric energy at the
• It can be use at any time when it necessary. terminal of the piezoelectric transducer. This small energy was
• Easy construction. stored in super capacitor. 20 pieces super capacitor and
• Less number of parts required. Produced electricity transducer parallel set up has constructed and we get 20 output
can be used for many purposes. voltages. In our proposed method we has used LM324
operation amplifier to add those output voltage together, as
V. SYSTEM ARCHITECTURE AND WORKING PROCEDURE shown in figure 3. These 20 transducers-super capacitors
The goal here to design a circuit in which sound or air produced about 4Voutput voltage. The saturation voltage of
pressure applied on piezoelectric transducer. In piezoelectric LM 324 Op amp is 5V. That is the biasing voltage Vcc=5V.
material sound or air pressure applied on piezoelectric Which indicates that it won’t be benefited if we added more
transducer as mechanical strain and electrical charges will be transducers-super capacitors before the adder circuit, because
produced on the faces of the crystal. In a piezoelectric it will exceeds the highest saturation voltage of LM
material, total induced charge Q is directly proportional to the 324.Output of the added circuit than applied to a quadrupler
applied force F, given by the relation, which will increase the added output voltage 4V to around
12V .For our experiment we have taken a 9V DC rechargeable
Q = kF, where k is a piezoelectric constant. battery and it’s found that with this quadrupler output of 12V,
a 9V DC rechargeable battery can easily be charged within
Here direct voltage from piezoelectric transducer is very few
half an hour. It was also observed that the quadrupler output
(200 mV – 2 V). Also, the nature of the produced electric voltage varies with the frequency of AC signal used to operate

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the buzzer. When there is no sound or low sound than the 4 10.70 10.70 11.49
output of Quadrupler will be below 9V and by flowing current 5 10.50 10.62 11.41
in reverse direction the battery will try to discharge. To 6 9.80 10.51 11.32
8 9.08 10.28 10.19
prevent this problem diodes have placed towards the
10 8.70 10.13 10.08
quadrupler to rechargeable battery. This diode works as 12 8.44 9.99 9.83
reverse biased and oppose the reverse flow of current from 14 7.80 9.80 9.78
battery. As a result the battery cannot get discharged in 18 7.50 9.73 9.70
absence of sufficient sound source. The complete system 16 7.20 9.65 9.63
architecture setup has shown in figure 4. 20 7.04 9.59 9.50
24 6.80 9.54 9.34
28 6.45 9.41 9.17
36 5.78 8.8 8.92
48 5.50 7.43 8.38
60 4.31 7.23 7.15
78 3.70 6.73 5.23
Output of the voltage quadrupler circuit was 12 volt with 60
mA from 118 dB sound. It’s found that with this output
voltage a fully discharge 9V DC battery can easily be fully
charged within only 30 minute. The proposed circuit could
generate 12 volt, so by increasing the number of our
experimented circuit we could easily increase up the output
voltage according to the desired voltage of a train
compartment. It has another advantage that the total cost of the
circuit is very low. We just need to spend money during on its
Fig. 4. Block Diagram showing the generating and storing electricity from initial setup but there is no running cost is zero.
sound source (Running train wheels).

VII. CONCLUSION
VI. SIMULATION RESULT In this paper, an effective and efficient new sound source has
The conversion circuit shown in Figure 4 has tested in introduced which can be used as a suitable renewable energy source.
outdoor environment to measure its performance. Tested Here continuous sound source from running train wheels is proposed
sound source was train wheels and it’s near air pressure. These as a new renewable sound source. The performance of the circuit for
different frequencies of sound was tested and it was observed that the
typical high sound sources usually play no role except
circuit works well for frequencies usually available from train
producing noise. As it experimented that the circuit could wheels.
generate electrical energy about 12V from a small sound
source, so it will be benefited if we place this circuit in a noisy References
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[8] Rahnuma Rifat Chowdhury , Muhammad Salahuddin Kabir,
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