This document discusses wireless power transfer technologies and their application to LED lighting systems. It begins with an introduction to wireless power transfer and wireless-driven LED systems. It then provides background on the history of wireless power by discussing Nikola Tesla's Tesla coil experiments. The document outlines four main methods of wireless power transfer: electromagnetic induction, capacitive coupling, resonant inductive coupling, and microwave transmission. It also discusses LEDs and their advantages for lighting. The document concludes that wireless power techniques have opportunities to make LED products more convenient and reliable compared to traditional wired systems.

1. WIRELESS DRIVEN LED
SEMICONDUCTOR
LIGHTNING SYSTEM
MALAVIKA S
S7 F
ROLL NO-33
1

2. CONTENTS
• Introduction
• History of power transfer
• Tesla coil
• General principle and classification of wireless
power transfer
• Electromagnetic induction
• Capacitive coupling
• Types of capacitive coupling
• Resonant inductive coupling
• Microwave transmission
• LED
• Application
• Conclusion
• Reference 2

3. INTRODUCTION
• Transmission of electrical energy from a power source to an electrical load
without man-made conductors.
• The wireless-driven led (wd-led) -combine the advantages of wireless
electrical power transfer and led semiconductor lighting technology
• Traditional led lighting system sensitive to rigid environment such as
humidity, corrosive and flammable
• The wireless-driven LED lighting system should contain LED lighting
module, wireless electrical power transfer system, LED driving circuit and
electrical energy storage system.
3

4. HISTORY OF POWER TRANSFER
Tesla coil
 A Tesla coil is an electrical resonant transformer circuit invented by
Nikola Tesla around 1891
 It is used to produce high-voltage, low-current,
high frequency alternating-current
 Tesla used his Tesla coil circuits to perform the first experiments
in wireless power transmission at the turn of the 20th century 4

5. 0PERATION
• The high electric field causes the air around the high voltage
terminal to ionize and conduct electricity
• Colorful corona discharge, brush discharge
• A Tesla coil is a radio frequency oscillator that drives an air-core
double-tuned resonant transformer to produce high voltages.
• Uses simple spark gap
5
Fig 1:tesla coil in operation

6. CONT..
6
 Transformer(T): to step the AC mains voltage up to a high enough voltage to
jump the spark gap(5 and 30kV).
 Capacitor (C1): with the primary winding L1 forms tuned circuit of the Tesla
transformer
 Spark gap(SG) that acts as a switch in the primary circuit
 Tesla coil (L1, L2): an air-core double-tuned resonant transformer, which
generates the high output voltage.
 Capacitive electrode(E): in the form of a smooth metal sphere
or torus attached to the secondary. Its large surface area suppresses
premature corona discharge and streamer arcs, increasing output voltage.
Fig 2:spark excited tesla
coil

7. GENERAL PRINCIPLE & CLASSIFICATION OF
WPT
1.Electro magnetic induction
• Known as inductive charging
• The transmitter(L1) and receiver coils(L2) form a transformer .
• AC through (L1) creates an oscillating magnetic field (B) by Ampere's
law.
• The magnetic field passes through (L2), where it induces an
alternating EMF (voltage) by Faraday's law of induction,which creates
an AC current in the receiver
7
Fig 3:electromagnetic induction

8. CONT..
• The power transferred increases with frequency and the mutual
inductance M, which depends on the distance D between them
• A widely-used figure of merit is the coupling coefficient(K) ,equal to the
fraction of magnetic flux through L1 that passes through L2.
• Safe way of connection, the products can be enclosed from air, water
or plastic in the atmosphere.
• The transmission power and efficiency will change if the distance
between the two coils become closer or farther
8

9. 2.CAPACTIVE COUPLING
• In capacitive coupling (electrostatic induction), 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. 9
Fig 4 a)capacitive coupled power transfer
b)simplified ckt

10. CONT..
• Voltage is applied to the transmitting plate, and the oscillating electric
field induces an alternating potential on the receiver plate by electrostatic
induction
• Causes an alternating current to flow in the load circuit
• The amount of power transferred increases with
the frequency, capacitance between the plates, proportional to the area
of the smaller plate and inversely proportional to the separation
10

11. CONT..
• Used for low power applications, because the very high voltages required to
transmit significant power can be hazardous,cause side effects such
as ozone production.
• Electric fields interact strongly with most materials, including the human body,
due to dielectric polarisation.
• The field is largely confined between the capacitor plates ,reduces interferences
• Alignment requirements between the transmitter and receiver are less critical
11

12. TYPES
• Bipolar design:two transmitter plate two receiver plates.
• Each transmitter plate is coupled to a receiver plate.
• The transmitter oscillator drives the transmitter plates in opposite phase by a
high alternating voltage
• The alternating electric fields induce opposite phase alternating potentials in
the receiver plates
• This "push-pull" action causes current to flow back and forth between the
plates through the load.
• The two plates in the receiving device must be aligned face to face with the
charger plates
12

13. • Unipolar design: the transmitter and receiver have only one active
electrode,
• Either ground or large inactive capacitive electrode serves as the return
path for the current.
• The transmitter oscillator and the load is connected between the electrodes
and a ground connection,
• Inducing an alternating potential on the nearby receiving electrode , causing
alternating current to flow through the load and ground. 13

14. 3.RESONANT INDUCTIVE COUPLING
• Resonant inductive coupling or electro dynamic induction
• Wireless transmission of electrical energy between two magnetically
coupled coils that are part of resonant circuits tuned to resonate at the same
frequency.
• 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 14

15. CONT..
• 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
• Because the coil is highly resonant,energy placed in the coil dies away
relatively slowly , if a second coil is brought near it, the coil can pick up most of
the energy before it is lost
• The fields used are predominately non-radiative , near field hardware is kept
well within the 1/4 wavelength distance they radiate little energy from the
transmitter to infinity.
• If two coils resonate with the same frequency, a lot of energy moves from the
transmitting coil to the receiving coils
15

16. 4. MICROWAVE TRANSMISSION
• Transmitting energy by the use of electromagnetic waves called
microwaves
• Frequency range (1ghz to 300ghz)
• Wavelength (30cm down to 1cm)
• Distance covered by microwave signal depends on antenna height.
• To increase coverage each antenna has a built in repeater that
regenerates that signal before passing it on to the next antenna
• Antennas are placed for each 25miles
• Microwave power transmission belongs to a long-distance power
transmission technology.
16

17. • The 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.
It relies on three key elements:
1.Use of radio frequency to achieve transmission
2.Clear line of sight with no obstacle in path way
3.Regular relay stations required due to line of sight and cost consideration
17

18.  ADVANTAGE
• Multiple channel
• Large bandwidth
 DISADVANTAGE
• Towers are expensive to build
• Signal absorption by atmosphere
• Line of sight will be disrupted by obstacles
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19. LED
• LED is a PN junction diode which emits light when forward biased
• The amount of light output is directly proportional to forward current.
• N-type layer is formed on a P-type substrate by a diffusion process.
• Terminals from both layer make anode and cathode .
• light energy is released at the junction when electrons and holes are
recombined.
• After recombination the electrons in the conduction band of N-region
falls into the holes in the valance band of P-region .
• The difference in energy between the conduction band and valance
band is radiated in the form of light
19

20. • The semiconductor material used for manufacturing LED:
Gallium arsenide-infrared radiation
Gallium phosphide-red or yellow
Gallium arsenide phosphide-red or green
Gallium nitride-blue
• Si and Ge is not used ,because they are heat producing materials
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21. ADVANTAGE
• Products are more convenient by eliminating the wires in the lighting
system.
• Safer and more reliable by eliminating the fire hazard and risk of short
circuit with conductive interconnections,
• Waterproof and explosion proof by removing the electric contacts and
wires that connect led lighting module
• More flexible by transferring electric power to LED lighting module
through air, water, glass and plastic without any electric connection.
• Improve the reliability
• Electrical shock protection,
• Portable and environmentally sound
21

22. CONCLUSION
• Opportunities and challenges always go alone with the new
technologies.
• 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 system
• And with the commercialization of wireless-driven LED products,
more and more related applications will be found.
22

23. REFERENCE
[1] 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 23

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