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Design and Development of a Wireless Lamp Charging System

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Wireless is a technology of transmitting power through an air gap to electrical devices for the purpose of energy replenishment. The recent progress in wireless charging techniques and development of commercial products has provided a promising alternative way to address the energy tailback of unadventurously portable-power devices. This work is an innovative application of Faraday's laws of electromagnetic induction. A charging station sends energy through inductive coupling to an electrical device, which stores the energy in the batteries. Because there is a small gap between the two coils, inductive charging is one kind of short-distance wireless energy transfer. Induction coils are attached to transmitter and the portable device, so that the device receives power from the electromagnetic field created by the transmitting unit and stores the energy in the battery.
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Page 1-9 © MAT Journals 2017. All Rights Reserved
Journal of Power Electronics and Devices
Volume 3 Issue 1
Design and Development of a Wireless Lamp Charging System
Engr. Ajayi-Smart Emmanuel Abiodun
Department of Computer Engineering, Ekiti State University,
AdoEkiti, Ekiti State, Nigeria
E-mail: ajayismartea@yahoo.com
Abstract
Wireless is a technology of transmitting power through an air gap to electrical devices for
the purpose of energy replenishment. The recent progress in wireless charging techniques
and development of commercial products has provided a promising alternative way to
address the energy tailback of unadventurously portable-power devices. This work is an
innovative application of Faraday’s laws of electromagnetic induction. A charging station
sends energy through inductive coupling to an electrical device, which stores the energy in
the batteries. Because there is a small gap between the two coils, inductive charging is one
kind of short-distance wireless energy transfer. Induction coils are attached to transmitter
and the portable device, so that the device receives power from the electromagnetic field
created by the transmitting unit and stores the energy in the battery.
Keywords: Wireless, lamp, energy, electromagnetic induction, power
INTRODUCTION
In this eon of modernization and
rejuvenation, electricity has become the
insurmountable cup of life. A spell without
electricity makes the 2lst Century-Man’s
thinking go dry. The cradle of the
orthodox form of electricity is through
wires. But thankfully, rigorous and
continuous research and development has
brought frontward a major discovery, and
this provides electricity devoid of the use
of wires. This wonder baby is called
Inductive charging or wireless charging.
The term inductive charging was coined
by Dave Gerdingnow being used by the
MIT researchers and every other living
being today. Inductive charging works on
the principle of a transformer[6] (a device
that transfers electrical energy from one
circuit to another through inductively
coupled conductors).
The nitty-gritty of this technology dates
back to the 19th century, (in the 1890s)
where it was first introduced by an
American Serbian scientist known as
Nikola Tesla. He used conduction-based
systems instead of resonance magnetic
fields to transfer wireless power. He
captured the imagination of the world with
his invention of the Tesla coil, a device
that could transmit electricity through the
air, no wires required [8]. More than 100
years later, the world would respond by
adapting this breakthrough technology.
But things are notably moving rapidly in
the world of wireless power transfer, with
some new notions coming to the vanguard
in the last few years, also more and more
gadget makers are getting the hip of the
idea of a world without power bricks, this
technology is classed as one that is about
to explode[17].
Computer and Electronics Engineering
have become very broad fields in the
recent infrastructure of the world due to
the increasing demand for electronic
devices, which in turn reduced human
efforts by factor of tens[16]. One of the
largest and hottest torrents of this sea is
Wireless Electronics Systems.
Engineering is slightly saturating in some
of the torrents such as pure digital
electronics.
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Journal of Power Electronics and Devices
Volume 3 Issue 1
In this fast growing electronics world
many electronic devices have increased
dramatically over the years. But there are
few tradeoffs in the field of electronics,
such as, efficiency, convenience and cost
issues. Efficiency issue includes losses due
to heating of the devices and other losses
in the transmission and transfers of energy.
Also some of the electronics devices are
not available commercially because the
efficiency problem is solved with higher
cost and high-technology logic circuits and
their user interface comes with lots of
human efforts[13]. One of the biggest
issues encountered is convenience for the
portable devices such as: carrying the
charging cords and adapters everywhere
you go. Many people have more than one
portable device nowadays and each comes
with its own power charger. Since we
claim to live in a wireless world should we
lack the successful use of Wireless Power
Transfer devices? No!
Inductive charging will ensure that cell
phones, laptops, tablets and other power-
gluttonous devices get charged on their
own, jettisoning the need of ever plugging
them in. Even better, because of Inductive
charging some of the devices won't require
batteries to function[11]. This powered
coil will create an electromagnetic field
around itself, and when a second induction
coil gets near enough, the power
willautomatically be transferred to it and
converted back into an electrical current.
By installing the second coil inside another
device, youcan wirelessly supply power
which can then be used to activate the
device, and chargeits batteries.
Although most induction chargers only
operate over a short distance, however,
and while physical contact between a
device and its base unit isn't necessary for
induction to work, the fields generated are
so weak that it is usually the only way to
get close enough[7].
WIRELESS/INDUCTIVE APPLICATIONS
Wireless/inductive charging technology
for mobile phones was first introduced by
the Finnish company Nokia in late 2011,
their first wireless charging models were
the Lumia model 800 series to their current
flagship Lumia 950 and 950 XL.
In 2014 Miller Paul created his own
wireless phone charger called the Palm
Pre's wireless charger compliant with Qi
enabled devices e.g. Lumia 925, Galaxy
S5 et al.
Wireless /inductive charging technology
for electric vehicles; In 2013 the American
car manufacturer Chrysleradded built-in
wireless charging option to their 2013
Dodge Dart, also the technology is called
Qi (pronounced "Chee"), and it is available
on the 2014 Jeep Cherokee and also in
Toyota Avalondue.)
In early 2013 Oral Bintroduced
toothbrushes that used wireless/inductive
charging technology, to charge their
toothbrushes without the risk of
electrocution due to the plastic covering in
both ends.
A rechargeable lamp that charges and
works wirelessly without
physical/conventional contact[5][17].
This enhances reliability; since the
charging plug on the lamp may suffer
mechanical or physical damage easily, this
type of charging standard is needful, also
because a given standard is used we can
basically charge several lamps with one
wireless charger[10] (albeit not at the same
time)
To reduce electric shock, plugging and
unplugging a cable is more dangerous
because there is a minute chance it could
fray and shock you. By contrast, induction
hardware can be safely encased in thick
plastic and still work[8].
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Page 1-9 © MAT Journals 2017. All Rights Reserved
Journal of Power Electronics and Devices
Volume 3 Issue 1
The make sure that the induction charger
creates a field that is not dangerous to have
any effect on the human body. This is
going to be achieved by using high quality
premium copper coils.
This is why electric toothbrushes have
long used induction to charge: the units
can remain sealed and waterproof.
METHODOLOGY
The action of an electrical transformer is
the simplest instance of wireless energy
transfer[14]. The primary and secondary
circuits of a transformer are not directly
connected. The transfer of energy takes
place by electromagnetic coupling through
a process known as mutual induction.
There is also an added benefit, because of
the ability to step the primary voltage
either up or down. The battery charger of a
mobile phone or the transformers on the
street is examples of how this principle can
be used[3]. Induction cookers and many
electric toothbrushes are also powered by
this technique. The main drawback to
induction, however, is the short range. The
receiver must be very close to the
transmitter or induction unit in order to
inductively couple with it. To create a
working wireless charging system and
transfer electrical energy, we need both the
receiver and the transmitter coil to run at
same frequency[2][4]. In other words,
impedance of both receiver and transmitter
should be matched in order to transfer
maximum possible energy[9][5].
This circuit mainly works on the principle
of mutual inductance. Power is transferred
from transmitter to the receiver wirelessly
based on the principle of “inductive
coupling”[12].
Fig 1: Schematic diagram of Wireless
Charging System
The first circuit is used to produce voltage
wirelessly, initially a transformer is used to
step down the voltage from 220 V to 12V.
This step-down voltage is applied to the
diode. The IN4007 diode is used to allow
the voltage to flow in one direction only.
This is then passed to the 7812 voltage
regulator. The output of this regulator is a
12V DC voltage[15]. Two capacitors are
placed before and after the voltage
regulator to eliminate the ripples[13]. Next
it is connected to the oscillator circuit. It
produces a frequency. The values of
resistors and capacitors are calculated in
such a way that it produces oscillations.
Then it is fed to the inductor, the Inductor
is used to induce the voltage in the second
circuit. In the second circuit, another
inductor is used for the mutual inductance.
A voltage multiplier circuit is used after
the inductor. It is then connected to the
voltage regulator 7805[1].
At the output of the regulator a capacitor is
connected. Thus output is connected to the
battery of the lamp.
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Journal of Power Electronics and Devices
Volume 3 Issue 1
Fig 2: The Standards for the Transmitters And Receiver
SYSTEM DESCRIPTION
The transmitting unit which transfers
power to the second unit, i.e. receiving
unit via inductively coupled coils. The
microcontroller sends instruction to the
LCD to display information as
programmed commands
This is divided into two units:
Transmitting Unit and Receiving unit.The
block diagram of wireless power system is
shown in fig 3. Power starts in the
transmitter mobile device battery and is
converted into AC power through the
power amplifier. Power is transferred
through the air between these two coupled
coils. The received AC power is then
rectified and is available to charge the
portable device battery and power a load.
Fig 3: Circuit Diagram of Wireless Charging System
The transmitter and receiver coils of the
system developed in this work are sized
after a common wireless power
application[17]. Thus, the receiver coil in
this system is designed to be 2cm in girth,
and 5cm from one end of the coil to
another and the transmitter coil is designed
to be larger, 10 cm, from one end to
another for better coupling with the
receiver coil. Power is transferred through
the air between these two coupled coils.
With these dimensions the
systemworksperfectly.
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Journal of Power Electronics and Devices
Volume 3 Issue 1
Table 1: Equipment Used for the System
S/N
Equipment
Type
1
Microcontroller
PIC 16F876A
2
Copper coil
Nil
3
Voltage Regulators
7805 and 7812
4
LED
Red
5
Resistors
4.7k,22k and 10k
6
Capacitors
Erie Ceramic
7
Diode
(1N4007)
8
Batteries
9V,3V
9
LCD Display (16 x 2)
10
Transistors
2N2222(NPN)
TESTING
Diverse tests were carried out on all the
components (for efficiency, workability
and usability). This was done at any and
every stage of construction. Tests were
also carried on the bread boarded work,
before the ultimate test on soldered work
on Vero board.
Components Test
All the components like: Resistors,
Capacitors, connecting wires, LEDs,
Transistors were tested with the help of a
digital multimeter to make certain their
values and also ensure that they were not
malfunctioning. Continuity was tested for
the connecting wires, while voltage
resistance was checked in some
components.
Breadboard Test
The circuit was first constructed on
breadboard, the bread boarded circuit was
lay open to numerous checks in order to
discern where there were lapses, and if
any, they were all fixed. Input and output
of each stage were tested and they all
kowtowed to the plan.
Veroboard Test
This was the last test carried out after the
all components had been soldered on Vero
board.
As this was the final stage of the
construction, arduous tests were carried
out here. A digital multimeter was used to
measure input voltage of each component
as well as its output voltage, and final
output of the wireless lamp charging
system was also measured.
Fig 4: Complete Construction of the Wireless lamp Charging System
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Page 1-9 © MAT Journals 2017. All Rights Reserved
Journal of Power Electronics and Devices
Volume 3 Issue 1
RESULTS
The lamp charges inductively without any
form of conventional contact from the
receiving unit and the transmitter unit. So,
the current received from the transmitter
unit varies with distance (as measured by
the Multimeter). Below is a table that
illustratesand also a corresponding graph.
Table 2: Comparison of distance(cm) to charge rate(maH)
Distance(cm)
Current(maH)
0.0
600
0.5
525
1.0
457
1.5
403
2.0
355
2.5
310
3.0
250
3.5
202
4.0
147
4.5
99
5.0
40
5.5
6
6.0
0
Fig 5: A graph of charging distance(cm) against output current(maH)
The deduction from the table and graph is
simple and very clear: The farther the
distance the lower the charge rate, Vice
versa
To make sure of the efficiency of the
project, I charged the lamp
conductively/conventionally and it took 2
hours (120 minutes) to fully charge. I also
charged the lamp inductively from a
distance of 0cm and it took 2hours 36
minutes (156 minutes) to charge it fully.
Relating this mathematically we have:
Full charge (inductive) = 100% = 156
minutes
Full charge (conductive) = 100% =120
minutes
E(Efficiency) =156-120= 36
E = * 100 = 30%
The calculation above indicates that the
inductive charging module is 30% less
efficient than the conductive charging
process (i.e. its 70% efficient)
With the knowledge of the efficiency
intact, I can move on to calculate the
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Page 1-9 © MAT Journals 2017. All Rights Reserved
Journal of Power Electronics and Devices
Volume 3 Issue 1
efficiency of the various distances from
the table 5 above.
D1 (distance 1): 0cm = *70 =
70%
D2 (distance 2): 0.5cm = *70 =
61.25%
D3 (distance 3): 1.0cm = *70 =
53.37%
D4 (distance 4): 1.5cm = *70 =
47.07%
D5 (distance 5): 2.0cm = *70 =
41.47%
D6 (distance 6): 2.5cm = *70 =
36.17%
D7 (distance 7): 3.0cm = *70 =
29.17%
D8 (distance 8): 3.5cm = *70 =
23.57%
D9 (distance 9): 4.0cm = *70 =
17.15%
D10(distance 10): 4.5cm = *70 =
11.55%
D11 (distance 11): 5.0cm = *70 =
4.67%
D12 (distance 12): 5.5cm = *70 =
0.7%
D13 (distance 13): 6.0cm = *70 =
0%
Fig 4.3 Results: Transmitting coil and Receiving coil
LIMITATIONS
Power is somewhat wasted due to mutual
induction. It will work for very short
distances only. If you want to use it for
long distances, then the number of
inductor turns should be high.
CONCLUSION
The project was aimed to design and
implement a wireless lamp charging
system. After undertaking different tests,
eventually the obliged outcome is put
forward; it is a convenient, “fast”, risk-free
and efficient approach to charge lamps.
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Page 1-9 © MAT Journals 2017. All Rights Reserved
Journal of Power Electronics and Devices
Volume 3 Issue 1
This assembly works anywhere within the
range of 0cm-5.5cm. At last, the obliged
result was attained for effective and
compelling result.
RECOMMENDATION
It is recommended that a means by which
users can charge their devices with greater
distance should be added, such that the
user is flexible while using the lamp,
concurrently as it is charging it may use.
It is indorsed that an automatic alarm or
notification system be instilled in the
future, as it will guarantee that users are
notified automatically of when their
devices are low in power at a certain range
within the transmitting unit. This can be
effected via NFC (Near Field
Communication) or Bluetooth
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