This document is a certificate certifying that Malavika S completed a seminar presentation entitled "Wireless driven LED semiconductor lightning system". It includes an abstract summarizing her seminar report, which proposed a wireless power transfer system to drive LED lighting. The system would contain an LED lighting module, wireless power transfer system using either inductive or magnetic resonance coupling, an LED driving circuit, and an energy storage system. The report discussed the history and principles of wireless power transfer technologies.

1. COLLEGE OF ENGINEERING, CHENGANNUR
KERALA
DEPARTMENT OF ELECTRICAL ENGINEERING
CERTIFICATE
This is to certify that the seminar entitled
Wireless driven LED semiconductor lightning system
Submitted by
MALAVIKA S( 19130661)
is a bonafidework done by her.
Head of the Department Coordinator

2. WIRELESS DRIVEN LED SEMICONDUCTOR
LIGHTNING SYSTEM
Seminar Report
Submitted in the partial fulfillment
of the requirements for the award
of the degree of
Bachelor of Technology
in
Electrical and Electronics Engineering
of
Cochin University of Science and Technology
by
MALAVIKA S
19130661
October, 2015
Department of Electrical Engineering
College of Engineering, Chengannur-689121
Phone: (0479) 2454125, 2451424 Fax: (0479) 2451424

3. ACKNOWLEDGEMENT
First and foremost I thank God Almighty for His grace and blessings, without
which this wouldn’t be possible.
I express my deep sense of gratitude to Prof. V P Jyothiraj, Principal,
College of Engineering Chengannur. I also express my gratitude to Dr. Deepa James, Head,
Department of Electrical and Electronics Engineering, who extended all support at her
disposal to its fullest, as always for the completion of my seminar.
I am greatly indebted to my seminar coordinator Miss. Lakshmi,
AsssociateProfessor, Department of Electrical and Electronics Engineering and Miss.
Vandana, Associate Professor, Department of Electrical and Electronics Engineering for
their scholarly assistance, kind treatment, encouragement and timely help in all possible
manners. I would also like to thank Mr. Bibin Baby John, Assistant Professor whose
timely guidance and advices have helped me in successful completion of my seminar.

4. ABSTRACT
Wireless power transfer technology is the transmission of electrical energy from a power
source to an electrical load without man-made conductors. Traditional LED lighting system
sensitive to rigid environment such as humidity, corrosive and flammable. Combining the
advantages of wireless electrical power transfer and LED semiconductor lighting technology,
the wireless-driven LED (WD-LED) lighting system has advantages of electrical shock
protection, convenient, reliable, portable and environmentally sound. The wireless-driven
LED lighting source will gain increasing attention in the civilian consumer electronics
market, military area and special lighting areas. To achieve wireless electric power transfer in
LED lighting system, the wireless-driven LED lighting system should contain LED lighting
module, wireless electrical power transfer system, LED driving circuit and electrical energy
storage system. The LED lighting module was driven by the electrical power, which was
transferred from a contact free system. Either inductive coupling or magnetic resonance
coupling is responsible for transferred the electrical power. Wireless-driven LED lighting
system has a good market prospects, this new technology will make these innovative LED
lighting products more available, convenient and reliable.

5. CONTENTS
1. INTRODUCTION
2. HISTORY OF POWER TRANSFER
2.1 TESLA COIL
3. .GENERAL PRINCIPLES AND CLASSIFICATIONOF WIRELESS
POWER TRANSMISSION SYSTEM
3.1 ELECTROMAGNETIC INDUCTION
3.2 CAPACITIVE COUPLIND
3.3 RESONANT INDUCTIVE COUPLING
3.4 MICROWAVE TRANSMISSION
4. LIGHT EMITTING DIODE
5. ADVANTAGES OF WD-LED SYSTEM
6. APPLICATION
7. CONCLUSION
8. REFERENCES

6. INTRODUCTION
When the interconnecting wires of lighting system are inconvenient, hazardous, or
impossible, some special lighting systems have higher requirements on reliability and
security, such as explosion- proof lamp, water-proof lamp, under-ground lamp.Owning to
higher request for water-proof, explosion- proof, the new engineering design must be
introduced into our lighting system. The concept of wireless power transfer can be dated back
to as early as year 1890 when Nicola Tesla made the first attempt to transfer considerable
amount of power without direct connection of wires, using Tesla coils designed by him. The
idea of transmitting electric power without wires has been around for over a century. In our
modern life, wireless communication has become an essential technology in many
areas.Wireless power transmission is the transmission of electrical energy from power source
to an electrical load without the use of interconnecting wires. Wireless transmission is useful
in cases where interconnecting wires are inconvenient, hazardous, or impossible. There are
four different fundamental methods for wireless energy transfer. The electrical energy can be
transferred by electromagnetism induction, capacitive coupling, magnetic resonance and
microwaves transmission. Traditional LED lighting system sensitive to rigid environment
such as humidity, corrosive and flammable. Combining the advantages of wireless electrical
power transfer and LED semiconductor lighting technology, the wireless-driven LED lighting
system is designed.The wireless-driven LED lighting system should contain LED lighting
module, wireless electrical power transfer system, LED driving circuit and electrical energy
storage system. The LED lighting module was driven by the electrical power, which was
transferred from a contact free system. Either inductive coupling or magnetic resonance
coupling is responsible for transferred the electrical power.

7. HISTORY OF POWER TRANSFER
TESLA COIL
A Tesla coil is an electrical resonant transformer circuit invented byNikola Tesla around 1891.
It
is used to produce high-voltage, low-current, high frequency alternating-current electricity. Tesla
experimented with a number of different configurations consisting of two, or sometimes three,
coupled resonantelectriccircuits.
Tesla used these coils to conduct innovative experiments in
electrical lighting, phosphorescence, X-ray generation, high frequency alternating
current phenomena, electrotherapy, and the transmission of electrical energy without wires.
Tesla used his Tesla coil circuits to perform the first experiments in wireless power
transmission at the turn of the 20th century,In the period 1891 to 1904 he experimented with
transmitting RF power between elevated metal terminals by capacitive coupling and between
coils of wire by inductive coupling
Tesla coil in operation, showing brush discharges from the toroid. The high electric
field causes the air around the high voltage terminal to ionize and conduct electricity,
producing colorfulcorona discharge, brush discharges and streamer arcs.
A Tesla coil is a radio frequency oscillator that drives an air-core double-tuned resonant
transformer to produce high voltages. Tesla's original circuits as well as most modern coils
use a simple spark gap to excite oscillations in the tuned transformer. More sophisticated
designs use transistor or thyristor switches or vacuum tube electronic oscillators
Tesla coils can produce output voltages from a hundred kilovolts to several million volts for
large coil. The alternating current output is in the low radio frequency range, usually between
50 kHz and 1mHz. Although some oscillator-driven coils generate a continuous alternating
current, most Tesla coils have a pulsed output the high voltage consists of a rapid string of
pulses of radio frequency alternating current.

8. The common spark-excited Tesla coil circuit, consists of these components:
 A high voltage supply transformer (T), to step the AC mains voltage up to a high
enough voltage to jump the spark gap. Typical voltages are between 5 and 30
kilovolts (kV).
 A capacitor (C1) that forms a tuned circuit with the primary winding L1 of the Tesla
transformer
 A spark gap (SG) that acts as a switch in the primary circuit
 The Tesla coil (L1, L2), an air-core double-tuned resonant transformer, which generates
the high output voltage.
 Optionally, a capacitive electrode (top load) (E) in the form of a smooth metal sphere
or torus attached to the secondary terminal of the coil. Its large surface area suppresses
premature corona discharge and streamer arcs, increasing the Q factor and output
voltage.
The specialized transformer coil used in the Tesla circuit, called a resonant
transformer, oscillation transformer, or RF transformer, functions differently from an
ordinary transformer used in AC power circuits While an ordinary transformer is designed
to transfer energy efficiently from primary to secondary winding, the resonant transformer is
also designed to store electrical energy. Each winding has a capacitance across it and
functions as an LC circuit (resonant circuit, tuned circuit), storing oscillating electrical
energy, analogously to a tuning fork. The primary winding (L1) consisting of a relatively few
turns of heavy copper wire or tubing, is connected to a capacitor (C1) through the spark
gap (SG).[14][15] The secondary winding (L2) consists of many turns (hundreds to thousands)
of fine wire on a hollow cylindrical form inside the primary. The secondary is not connected
to an actual capacitor, but it also functions as an LC circuit, the inductance (L2) resonates
with (C2), the sum of the capacitance between the windings of the coil, and the capacitance
of the toroidal metal electrode attached to the high voltage terminal. The primary and
secondary circuits are tuned so they resonate at the same frequency, they have the

9. sameresonant frequency. This allows them to exchange energy, so the oscillating current
alternates back and forth between the primary and secondary coils.

10. General Principle and Classification of The WirelessPower
Transmission System
A. Electromagnetism induction
Electromagnetism induction, also known as inductive charging is based on a few
simple principles. The technology usually requires two coils: a primary transmitter
and a secondary receiver. An alternating current is passed through the transmitter coil,
generating a magnetic field, as shown in Fig1. Then the receiver can transfer the
magnetic field to electric power. Induction usually use an induction coil to create an
alternating electromagnetic field from within a charging base station, and a second
induction coil in the portable device takes power from the electromagnetic field and
coverts it back into electrical current to power a device or charge the battery. The
electronic products which have the function of wireless power consortium require
more electronics and coils in both device and emitter, increasing the complexity and
cost products.
Figure 1 Electromagnetism induction by coils
In inductive coupling (electromagnetic induction or inductive power transfer, IPT), power
is transferred between coils of wire by amagnetic field. The transmitter and receiver coils
together form a transformer. An alternating current (AC) through the transmitter
coil (L1) creates an oscillating magnetic field (B) by Ampere's law. The magnetic field
passes through the receiving coil(L2), where it induces an alternating EMF (voltage)
by Faraday's law of induction, which creates an AC current in the receiver. The induced

11. alternating current may either drive the load directly, or be rectified to direct current (DC)
by a rectifier in the receiver, which drives the load.In most systems an electronic
oscillator generates a higher frequency AC current which drives the coil, because
transmission efficiency improves with frequency.The power transferred increases with
frequency and the mutual inductance M between the coils, which depends on their
geometry and the distance Drange between them. A widely-used figure of merit is
the coupling coefficient . This dimensionless parameter is equal to the
fraction of magnetic flux through L1 that passes through L2.This technology can
achieve the wireless power transfer without any electric connects. It provides a safe
way of connection, the products can be all enclosed and away from air, water or
plastic in the atmosphere. However, the transmission power and efficiency will
change if the distance between the two coils become closer or farther.
B. Capacitive coupling
Instead of using electromagnetism field induction, an alternative way of wireless
electric power transfer is to use electric field coupling to achieve capacitive power
transfer. As shown in Fig. 1a, a typical capacitive coupled electric power transfer
system is consisted of three parts, namely primary power transmitter, acting as a high
frequency voltage source; capacitive structure, functioning as the electric energy
transfer channel; and power receiver, acting as the secondary power conditioner, and
supply the electric power to the load. Ignoring the harmonics generated by the inverter
for simplification, a typical capacitive coupling power transfer system can be modeled
with a simple linear circuit as shown in Fig. 2b.

12. Figure 2a the structure of capacitive coupling power transfer, 2b the simplified Capacitive
power transfer circuit
As an alternative way of wireless power transmission, the capacitive coupling system has
some unique features. The coupling structure is very special, in the coupling part, the field is
mostly confined between metal plates, and the system employs the electric field as the
energy-carrying medium. Since the capacitive coupling is working under an alternative way,
there is very small power loss in the coupling structure as the system is operating. Due to the
capacitive structure in the coupling part, the electric field coupler functions as two capacitors
connected in series during the operation of the system. According to different applications,
the capacitive coupling structure can be designed to many different configurations.
In capacitive coupling (electrostatic induction), the dual of inductive coupling, power is
transmitted by electric field between electrodes such as metal plates. The transmitter
and receiver electrodes form a capacitor, with the intervening space as the dielectric.An
alternating voltage generated by the transmitter is applied to the transmitting plate, and
the oscillatingelectric field induces an alternating potential on the receiver plate
by electrostatic induction which causes an alternating current to flow in the load circuit.
The amount of power transferred increases with the frequency and
the capacitance between the plates, which is proportional to the area of the smaller plate
and (for short distances) inversely proportional to the separation.
Capacitive coupling has only been used practically in a few low power applications,
because the very high voltages on the electrodes required to transmit significant power
can be hazardous and can cause unpleasant side effects such as
noxious ozone production. In addition, in contrast to magnetic fields, electric fields
interact strongly with most materials, including the human body, due to dielectric
polarization. Intervening materials between or near the electrodes can absorb the
energy, in the case of humans possibly causing excessive electromagnetic field
exposure. however capacitive coupling has a few advantages over inductive. The field is
largely confined between the capacitor plates, reducing interference, which in inductive
coupling requires heavy ferrite "flux confinement" cores. Also, alignment requirements

13. between the transmitter and receiver are less critical. Capacitive coupling has recently
been applied to charging battery powered portable devices and is being considered as a
means of transferring power between substrate layers in integrated circuits
Capacitive wireless power systems
Bipolar
Unipolar
Two types of circuit have been used:
 Bipolar design: In this type of circuit, there are two transmitter plates and two
receiver plates. Each transmitter plate is coupled to a receiver plate. The
transmitter oscillator drives the transmitter plates in opposite phase (180° phase
difference) by a high alternating voltage, and the load is connected between the two
receiver plates. The alternating electric fields induce opposite phase alternating
potentials in the receiver plates, and this "push-pull" action causes current to flow
back and forth between the plates through the load. A disadvantage of this
configuration for wireless charging is that the two plates in the receiving device must
be aligned face to face with the charger plates for the device to work.
 Unipolar design: In this type of circuit, the transmitter and receiver have only one active
electrode, and either the ground or a large inactive capacitive electrode serves as the
return path for the current. The transmitter oscillator and the load is connected between
the electrodes and aground connection, inducing an alternating potential on the nearby
receiving electrode with respect to ground, causing alternating current to flowthrough the
load connected between it and ground.

14. C. Resonant inductive coupling
Resonant inductive coupling or electro dynamic induction is the near field wireless
transmission of electrical energy between two magnetically coupled coils that are part
of resonant circuits tuned to resonate at the same frequency. This process occurs in
a resonant transformer, an electrical component which consists of two coils wound on the
same core with capacitors connected across the windings to make two coupled LC circuits.
Resonant inductive coupling is also being used in wireless power systems. Here the two LC
circuits are in different devices; a transmitter coil in one device transmits electric power
across an intervening space to a resonant receiver coil in another device. This technology is
being developed for powering and charging portable devices. Resonant transfer works by
making a coil ring with an oscillating current. This generates an oscillating magnetic field.
Because the coil is highly resonant, any energy placed in the coil dies away relatively slowly
over very many cycles; but if a second coil is brought near it, the coil can pick up most of the
energy before it is lost, even if it is some distance away. The fields used are predominately
non-radiative, near fields, hardware is kept well within the 1/4 wavelength distance they
radiate little energy from the transmitter to infinity.
The coupling coefficient is the fraction of the flux of the primary that cuts the secondary coil,
and is a function of the geometry of the system.
The coupling coefficient, k, is between 0 and1.
Household devices produce relatively small magnetic fields. For this reason, chargers should
hold devices at the distance necessary to induce a current, which can only happen if the coils
are close together. A larger and stronger field could induce current from farther away, but the
process would be extremely inefficient. Meanwhile, a lot of power will be lost as the
transmission distance become larger, because the magnetic field spreads in all directions.
Resonant inductive coupling is the near field wireless transmission of electrical energy
between two coils that are tuned to resonate at the same frequency. An efficient way to
transfer power between coils separated by a few meters is that we could extend the distance
between the coils by adding resonance to the equation. Both systems should have the same
resonant frequency, the induction of electric power can be different.

15. Figure 3 Resonant induction coupling
As shown in Fig.3, each electronic device has a coupling receiver which consists of a cured
coil of wires as an inductor and a capacitance plate. As electricity travels through the
receiver, the coil begins to resonate. Its resonant frequency is a product of the inductance of
the coil and the capacitance of the capacitor. In the room, the emitter is the source of electric
energy. According to the theory, one coil can even send electricity to several receiving coils,
as long as they all resonate at the same frequency. Electricity, traveling along an
electromagnetic wave, can tunnel from one coil to the other as long as they both have the
same resonant frequency. As long as coils are out of the frequency range, resonant coupling
will not happen, since the magnetic fields around the coils aren’t strong enough to affect
much around them. Similarly, if the two coils resonate at different frequencies, nothing will
happen. But if two resonating coils with the same frequency get within a few meters of each
other, a lot of energy moves from the transmitting coil to the receiving coils, since they
resonate at the same frequency.

16. D Microwave power transmission
The above three power transmission methods belong to near-field techniques. Microwave
transmission refers to the technology of transmitting energy by the use of electromagnetic
waves whose wavelengths are conveniently measured in small numbers of centimeter (30cm
down to 1cm), these are called microwaves (1GHz to 300GHz). Microwave power
transmission is the use of microwaves to transmit power through outer space or the
atmosphere without the need for wires.The distance covered by microwave signal depends
upon height of antenna.in inorder to increase coverage each antenna has a built in reperater
that regenerates that signal before passing it on to the next antenna in line.the placement of
antenna to do this is approximately 25miles. It is a sub-type of the more general wireless
energy transfer methods. Microwaves power transmission is the most commonly proposed
method for transferring energy to the surface of the earth from solar power satellites or other
in-orbit power sources, or sending power to the earth from space. Microwave power
transmission belongs to a long-distance power transmission technology. It has more freedom
of choice of both receiver and transmitters, even mobile transmitters and receivers can be
chosen for the power transfer system. However, the total cost for the practical installation of
microwaves power transmission system is very high. Due to the working frequency or
wavelengths, the power in the transmission will interfere with present communication
systems.the main drawback of microwave sgnal is that they can be affected y weather
,especially rain.
It relies on three key elements:
 Use of radio frequency to achieve transmission(1GHz to 170GHz)
 Clear line of sight with no obstacle in path way
 Regular relay stations required due to line of sight and cost consideration
One of its major advantage is availability of multiple channel ,large bandwidth.
It also have some disadvantages like towers are expensive to build,signal absorption
by atmosphere(,microwave suffers from attenuation due to atmosphere),line of sight
will be disrupted if any obstacles such as new buildings are there in way.

17. LIGHT EMITTING DIODE
A PN junction diode which emits light when forward biased,is known as light emitting
diode(LED).The emitted light may be visible or invisible.The amount of light output is
directly proportional to forward current.Thus higher the forward current higher is the light
output. The arrow pointing on the symbol represent the light which is being transmitted away
from the junction.
Fig B shows the basic structure of a LED .here an N-type layer is formed on a P-type
substrate by a diffusion process.Then a thin P-type layer is grown on N-type layer.The metal
connection to both the layers make anode and cathode terminals are indicated.The light
energy is released at the junction when electrons and holes are recombined.The
recombination of holes and electrons takes place at the junction.After recombination the
electrons lying in the conduction band of N-region falls into the holes lying in the valance
band of P-region .The difference in energy between the conduction band and valance bandis
radiated in the form of light , in ordinary diodes this energy is radiated in the form of heat.
The semiconductor material used for manufacturing LED are gallium arsenide,gallium
arsenide phosphide,.The silicon and germanium is not used for manufacturing LED because
they are heat producing materials moreover they are very poor in emitting light radiations.
The LED’s radiate light in ifferent colour such as red ,green,yellow,blue,orange etc.some
LED’s emit infrared(invisible ) light also.the colour of emitted light depends upon type of
semiconductor used.Thus gallium arsenide emits infrared radiations,gallium arsenide
phosphide produces either red or yellow light,gallium phosphide emits red or green lightband
gallium nitride produces blue light.

18. Potential Applications of Wireless- driven LED Lighting System
Due to its unique features, WD-LED lighting system can be used in the following lighting
applications:
a) Wireless-driven/charging LED lighting systems
Schematic diagram of LED lights powered by wireless power transmission
LED lighting system can be directly powered with wireless electric power,
eliminating the electric connections compared to the traditional lighting products.
Combining the advantages of wireless electrical power transfer and LED
semiconductor lighting technology, the wireless-driven LED lighting system has
advantages of electrical shock protection, convenient, reliable, portable and
environmentally sound. As shown in Fig, to achieve wireless electric power transfer
in LED lighting system, the wireless-driven LED lighting system contain LED
lighting module, wireless electrical power transfer system, LED driving circuit and
electrical energy storage system. The LED lighting module was driven by the
electrical power, which was transferred from a contact free system. Either inductive
coupling or magnetic resonance coupling is responsible for transferred the electrical
power. Wireless-driven LED lighting system has a good market prospects, this new
technology will make these innovative LED lighting products more available,
convenient and reliable. In the movable light source field, the wireless-
driven/charging LED lighting systems with rechargeable battery have a good market
prospect. The movable LED lighting products are more convenient and safety with
wireless power technique. And in the plant lighting cultivation field, the WD-LED
lighting systems may float in the air or water without power cord, it is beneficial for
designers to design more novel lighting products.

19. b.Contact less driven led integrated chip or module
In this section, we mainly research in wireless electrical energy transmission tech,
LED integrated package tech, LED driver circuit tech.In recent years, many
researchers are working on the monolithic GaN optoelectronic system. In the future
research, the LED chips will be designed to be smaller to meet different application
requirements. However, as we all know, the traditional LED chips must have
positive and negative electrodes for electric connection and carrier injection. But the
electrodes take a part of area on chips, determining the chip can’t be too small.This
situation will be changed if wireless power technique is applied in the design of
monolithic LED optoelectronic devices. the monolithic GaN optoelectronic device
with wireless power technique include optoelectronic technology, TSV technology,
multilayer metal interconnection technology, LED drive circuit technology. The
monolithic LED chip can be powered without any electric connect, since a wireless
power receiver is integrated in the chip. If this integrated technology can be
achieved, it will be used in LED lighting field, decoration field, high resolution LED
TV.

20. ADVANTAGES
There are several motivations or advantages for apply this technology to the design of LED
lighting products, such as the following:
Advantages
 Make LED lighting products more convenient and novel to consumers, by
eliminating the wires as drive the lighting system.
 Make LED lighting products safer and more reliable by eliminating the fire hazard
and risk of short circuit with conductive interconnections, making the LED lighting
system waterproof and explosion proof by removing the electric contacts and wires
that connect LED lighting module with drive circuit or grid.
 Make the design of LED lighting products more flexible by using wireless power
technique, transferring electric power to LED lighting module through air, water,
glass and plastic without any electric connection.
 Improve the reliability by using wireless-driven method to separate the drive circuit
from lightning chips.
 electrical shock protection
 portable and environmentally sound.

21. CONCLUSION
Opportunities and challenges always go alone with the new technologies. As the wireless-
driven LED system, different products will have different problems in the design and
fabrication of new system. According to the design of different products and application
field, suitable wireless power transmission should be chose. A new technology always finds
its value only in that it can be applied in practical and commercial products. In many areas,
the wireless power technique can be integrated with LED lighting or display system, which
can make LED products more convenient or reliable compared to the traditional form or
design method. And with the commercialization of wireless-driven LED products, more and
more related applications will be found.

22. REFERENCE
1. Wikipedia.(2012,August7).Teslacoil[Online]Avaliable:http://en.wikipedia.org/wiki/Tesla
coil
2. Liang Huang and Aiguo Patrick Hu, “An overview of capacitively coupled power
transfer—a new contactless power transfer solution”, 2013 IEEE 8th Conference on
Industrial Electronics and Applications(ICIEA), pp 461- 464.
3. http://en.wikipedia.org/wiki/Microwave_transmission
4. Vikash Choudhary and Satendar Pal Singh, “Wireless Power Transmission: An Innovative
Idea”, International Journal of Educational Planning & Administration. ISSN 2249-3093
Volume 1, Number 3 (2011), pp. 203-210