we interim report

8/2/2019 WE Interim Report

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Project Report

WIRELESS ELECTRICITY

Submitted By

Roll No.: STUDENT NAME

2K8-MRCE- EC-117 Sakshi Sharma

2K8-MRCE- EC-120 Shashank Gupta

2K8-MRCE- EC-127 Trikeshwar Singh Braria

2K8-MRCE- EC-129 Vaibhav Gupta

April 2012

MANAV RACHNA COLLEGE OF ENGINEERING

ECE DEPARTMENTAFFILIATED BY MAHARISHI DAYANAND UNIVERSITY, ROHTAK


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CERTIFICATE

This is to certify that the following students:-

Sakshi Sharma (2K8-MRCE- EC-117)

Shashank Gupta (2K8-MRCE- EC-120)Trikeshwar Singh Braria (2K8-MRCE- EC-127)

Vaibhav Gupta (2K8-MRCE- EC-129)

have worked on the project Wireless Electricity and completed it successfully.

Project Guide Project Coordinator

MR. SATYAM K. SHARMA MS. MAYA SAXENA

HOD of ECE Department

MR. INDRASH BABBAR

2012

DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING

MANAV RACHNA COLLEGE OF ENGINEERING, FARIDABAD

(AFFILATED TO MAHARISHI DAYANAND UNIVERSITY)

DISTRICT FARIDABAD


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ABSTRACT

Transmission of electrical energy from one object to another without the use of wires is

called as Wireless Electricity. Wireless Electricity will ensure that the cellphones, laptops,

iPods and other power hungry devices get charged on their own, eliminating the need of

plugging them in and with every family member owning their cellphones, the drawers are

overflowing with all sorts of wires. How many times have you wished if there could be some

way to do away with all the wiry clutter? When you are on the way to work and your

cellphone beeps in hunger for a battery charge, haven't you wished for your cellphone

battery to get 'self charged'. Even better, because of Wireless Electricity some of the

devices won't require batteries to operate.

This remarkable discovery of the "True Wireless" and the principles upon which

transmission and reception, even in the present day systems, are based, Dr. Nikola Tesla

shows us that he is indeed the "Father of the Wireless." The most well- known and famous

Wardenclyffe Tower (Tesla Tower) was designed and constructed mainly for wireless

transmission of electrical power, rather than telegraphy. The most popular concept known is

Tesla Theory in which it was firmly believed that Wardenclyffe , would permit

wireless transmission and reception across large distances with losses . In spite of

this he had made numerous experiments of high quality to validate his claim of possibility of

wireless transmission of electricity. But this was an unfortunate incidence that people of that

century was not in a position to recognize his splendid work otherwise today we may

transmit electricity wirelessly and will convert our mother earth a wonderful adobe full of

electricity.

Wireless Electricity - Wireless Electricity, these words are simpler said than done. The

concept behind this fascinating term is a little complex. However, if you want to understandit, try and picture what I state in the next few lines. Consider two self resonating copper coils

of same resonating frequency with a diameter 20 inches each. One copper wire is

connected to the power source (Wireless Electricity transmitter), while the other copper

wire is connected to the device (Wireless Electricity Receiver).


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The electric power from the source causes the copper coil connected to it to start

oscillating at a particular (MHz) frequency. Subsequently, the space around the copper

coil gets filled with non- magnetic radiations. This generated magnetic field further transfers

the power to the other copper coil connected to the receiver. Since this coil is also of the same

frequency, it starts oscillating at the same frequency as the first coil. This is known as

'coupled resonance' and is the principle behind Wireless Electricity.

Imagine

Wireless Electricity will ensure that the cellphones, laptops, iPods and other power hungry

devices get charged on their own, eliminating the need of plugging them in. Even better,

because of Wireless Electricity some of the devices won't require batteries to operate.

But as success doesnt come easy the main hindrance to this concept is that the range of the

wireless electricity transfer is very small but efforts to improve the range are in progress and

this concept will surely emerge out as a successful phenomenon in the near future.


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Contents

Chapter 1. Introduction and Aim of the project...8

1.1 Advantages and Applications.9

Chapter 2. Wireless Electricity Technology: The Basics

2.1 The Basic Elements

2.1.1 Electricity12

2.1.2 Magnetism . 12

2.1.2 Electromagnetism . 12

2.1.3Magnetic induction . 12

2.1.4 Energy Power Coupling .13

2.1.5 Resonance13

2.1.6 Resonant Magnetic Coupling ... 13

2.1.7 Wireless Electricity Technology 14

Chapter 3. Hardware.15

3.1 Block Diagram15

3.2 Block Diagram Description.15

3.3 Circuit Diagram ..17

3.4 Circuit Diagram Description....17

3.5 Working.18

3.6 Testing18

3.7 Flowchart..19


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Chapter 4. Wireless Electricity is More Than.20

4.1 Traditional Magnetic Induction......20

4.2 Radiative Power Transfer21

4.3 Magnetic Resonance Imaging (MRI)22

4.4 Tesla's Vision of a Wireless World22

Chapter 5. Features and Benefits..23

5.1Highly Resonant Strong Coupling Provides High Efficiency OverDistance..23

5.1.1 Energy transfer and efficiency

5.1.2 Coupling coefficient

5.1.3 Power transfer

5.1.4 Voltage gain

5.1.5 Transmitter coils and circuitry

5.1.6 Receiver coils and circuitry

5.2Energy Transfer via Magnetic Near Field Can Penetrate and WrapAround Obstacles23

5.2.1 Electrostatic Induction Method

5.3Non-Radiative Energy Transfer is Safe for People andAnimals..23

5.4Scalable Design Enables Solutions from milliwatts toKilowatts24

5.5Flexible Geometry Allows Wireless Electricity Devices to beembedded into OEM Products24

Chapter 6. Questionnaire..25

Chapter 7. Conclusion..27
http://en.wikipedia.org/wiki/Resonant_inductive_coupling#Energy_transfer_and_efficiencyhttp://en.wikipedia.org/wiki/Resonant_inductive_coupling#Coupling_coefficienthttp://en.wikipedia.org/wiki/Resonant_inductive_coupling#Power_transferhttp://en.wikipedia.org/wiki/Resonant_inductive_coupling#Voltage_gainhttp://en.wikipedia.org/wiki/Resonant_inductive_coupling#Transmitter_coils_and_circuitryhttp://en.wikipedia.org/wiki/Resonant_inductive_coupling#Receiver_coils_and_circuitryhttp://en.wikipedia.org/wiki/Resonant_inductive_coupling#Receiver_coils_and_circuitryhttp://en.wikipedia.org/wiki/Resonant_inductive_coupling#Receiver_coils_and_circuitryhttp://en.wikipedia.org/wiki/Resonant_inductive_coupling#Transmitter_coils_and_circuitryhttp://en.wikipedia.org/wiki/Resonant_inductive_coupling#Voltage_gainhttp://en.wikipedia.org/wiki/Resonant_inductive_coupling#Power_transferhttp://en.wikipedia.org/wiki/Resonant_inductive_coupling#Coupling_coefficienthttp://en.wikipedia.org/wiki/Resonant_inductive_coupling#Energy_transfer_and_efficiency


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Appendix A. References.28

B. List of diagrams...29

C. Detail of componentsused...31


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CHAPTER 1. Introduction

In this era of modernization, electricity has become the cup of life. A moment without

electricity makes your thinking go dry. The major source of conventional form of electricity

is through wires. The continuous research and development has brought forward a major

breakthrough, which provides electricity without the medium of wires. This wonder baby is

called Wireless Electricity.

There are certain small but very useful discoveries made in history, which changed the world

forever, Newtons gravitational law, Watts steam engine,Thomsons bulb and many more.

But a renaissance occurred with the invention of Electromagnetic Waves by Maxwell. Sir

Jagdish Chandra Bose successfully generated electromagnetic waves having wavelength in

the range of 5mm to 25 mm. Thereafter an Italian scientist named Marconi succeeded in

transmitting electromagnetic waves up to a distance of several miles.

And with this there started a new era called WIRELESS TECHNOLOGY. Today, as we can

see the word wireless is common in day today life. Wireless communication has made

the world smaller. Almost each and everything is wireless or cordless. Cordless mouse,

cordless keyboard, satellite communication, mobiles, cordless microphones and headphones,

wireless internet service i.e. WIFI, etc. And these have definitely increased the standard of

living.

In fact it dates back to the 19th century, when Nikola Tesla used conduction based systems

instead of resonance magnetic field to transfer wireless power. As it is in Radiative mode,

most of the Power was wasted and has less efficiency. Further, in 2005, Dave Gerding coined

the term Wireless Electricity which is being used by the MIT researchers today.

Moreover, we all are aware of the use of electromagnetic radiations(radio waves) which is

quite well known for wireless transfer of information. In addition, lasers have also been used

to transmit energy without wires. However, radio waves are not feasible for power

transmissions because the nature of the radiation is such that it spreads across the place,

resulting into a large amount of radiations being wasted. And in the case of lasers, apart from

requirement of uninterrupted line of sight (an obstacle hinders the transmission process).

Transmission of electrical energy from one object to another without the use of wires iscalled as Wireless Electricity. Wireless Electricity will ensure that the cellphones, laptops,


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iPods and other power hungry devices get charged on their own, eliminating the need of

plugging them in. Even better, because of Wireless Electricity some of the devices won't

require batteries to operate.

Figure 1. Nikola Tesla

Aim

To successfully transfer electricity wirelessly.

1.1 Advantages and Applications

Wireless Electricity wireless power transfer technology can be applied in a wide

variety of applications and environments. The ability of our technology to transfer

power safely, efficiently, and over distance can improve products by making them

more convenient, reliable, and environmentally friendly. Wireless ElectricityTechnology

can be used to provide:

Direct Wireless Powerwhen all the power a device needs is provided wirelessly and

no batteries are required. This mode is for a device that is always used within range of its

Wireless Electricity power source.

Automatic Wireless Chargingwhen a device with rechargeable batteries charges

itself while still in use or at rest, without requiring a power cord or battery replacement. This


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mode is for a mobile device that may be used both in and out of range of its Wireless

Electricity power source.

Wireless Electricity technology is designed for Original Equipment Manufacturers (OEM's)

to embed directly in their products and systems.

Wireless Electricity technology will make your products:

More Convenient:

No manual recharging or changing batteries.

Eliminate unsightly, unwieldy and costly power cords.

More Reliable:

Never run out of battery power.

Reduce product failure rates by fixing the weakest link: flexing wiring and mechanical

Interconnects.

More Environmentally Friendly:

Reduce use of disposable batteries.

Use efficient electric 'grid power' directly instead of inefficient battery charging.

Consumer Electronics

Automatic wireless charging of mobile electronics (phones, laptops, game controllers, etc.) in

home, car, office, Wi-Fi hotspots while devices are in use and mobile.

Direct wireless powering of desktop PC peripherals: wireless mouse, keyboard, printer,

speakers, display, etc. eliminating disposable batteries and awkward cabling.


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Figure 2: Consumer Applications

Industrial

Direct wireless power for wireless sensors and actuators, eliminating the need for

expensive power wiring or battery replacement and disposal.

Figure 3: Industrial Applications

Future Applications

Direct wireless power interconnections and automatic wireless charging for implantable

medical devices (ventricular assist devices, pacemaker, etc.). Automatic wireless charging

and for high tech military systems (battery powered mobile devices, covert sensors,

unmanned mobile robots and aircraft, etc.).

Direct wireless powering and automatic wireless charging of smart cards.

Direct wireless powering and automatic wireless charging of consumer appliances, mobilerobots, etc.


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Figure 4: Future Applications


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4

: as c ectr c ty ec no ogy

Wireless Electricity technology is transferring electric energy or power over distance without wires.

with the basics of electricity and magnetism, and work our way up to the Wireless Electricity

technology.

2.1 The Basic Elements

Electricity:The flow of electrons (current) through a conductor

(like a wire), or charges through the atmosphere (like lightning). A

convenient way for energy to get from one place to another.

Magnetism:A fundamental force of nature, which causes certain

types of materials to attract or repel each other. Permanent magnets,like the ones on your refrigerator and the earth's magnetic field, are

examples of objects having constantmagnetic fields.

Oscillating magnetic fields vary with time, and can be

generated by alternating current (AC) flowing on a wire. The

strength, direction, and extent of magnetic fields are often

represented and visualized by drawings of the magnetic field lines.

Figure 5: An illustration

representing the

earth's magnetic field

Electromagnetism: A term for the interdependence of time-

varying electric and magnetic fields. For example, it turns out that and

oscillating magnetic field produces a magnetic an electric field andan

oscillating electric field produces field.

Magnetic Induction:A loop or coil of conductive material like

copper, carrying an alternating current (AC), is a very efficient

structure for generating or capturing a magnetic field.

If a conductive loop is connected to an AC power source, it will

generate an oscillating magnetic field in the vicinity of the loop. A

second conducting loop, brought close enough to the first, may

capture" some portion of that oscillating magnetic field, which in

turn, generates or induces an electric current in the second coil. The

current generated in the second coil may be used to power devices.

This type of electrical power transfer from one loop or coil to another

is well known and referred to as magnetic induction. Some common

examples of devices based on magnetic induction are electric

transformers and electric generators.

Figure 6:As electric current ,I

flow in the circuit it give rise

to a magnetic field, which

wrap around wire and when

current is reversed magnetic

field also get reversed

Figure 7: The blue

lines represent the

magnetic field when

current flows through

a coil and current is

reversed, magnetic

field also get reversed


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Energy/Power Coupling: Energy coupling occurs

when an energy source has a means of transferring energy

to another object. One simple example is a locomotive

pulling a train carthe mechanical coupling between

the two enables the locomotive to pull the train, and

overcome the forces of friction and inertia that keep the

train stilland, the train moves. Magnetic coupling

occurs when the magnetic field of one object interacts

with a second object and induces an electric current in or

on that object. In this way, electric energy can be

transferred from a power source to a powered device.

In contrast to the example of mechanical coupling given

for the train, magnetic coupling does not require any

physical contact between the object generating the energy

and the object receiving or capturing that energy.

Figure 8: An electric transformer is

a device that uses magnetic induction

to transfer energy from its primary

winding to its secondary winding,

without the windings being

connected to each other. It is used to

"transform" AC current at one

voltage to AC current at a differentvoltage.

Resonance: Resonance is a property that exists in many different physical systems. It can be

thought of as the natural frequency at which energy can most efficiently be added to an oscillating

system. A playground swing is an example of an oscillating system involving potential energy and

kinetic energy. The child swings back and forth at a rate that is determined by the length of the

swing. The child can make the swing go higher if she properly coordinates her arm and leg action

with the motion of the swing. The swing is oscillating at its resonant frequency and the simple

movements of the child efficiently transfer energy to the system. Another example of resonance is

the way in which a singer can shatter a wine glass by singing a single loud, clear note.

In this example, the wine glass is the resonant oscillating system. Sound waves traveling through

the air are captured by the glass, and the sound energy is converted to mechanical vibrations of the

glass itself. When the singer hits the note that matches the resonant frequency of the glass, the

glass absorbs energy, begins vibrating, and can eventually even shatter. The resonant frequency of

the glass depends on the size, shape, thickness of the glass, and how much wine is in it.

Resonant Magnetic Coupling: Magnetic coupling occurs when two objects exchange

energy through their varying oscillating magnetic fields. Resonant coupling occurs when the

natural frequencies of the two objects are approximately the same.


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Figure 9: Two idealized

resonant magnetic coils, shown

in yellow. The blue and red

color bands illustrate their

magnetic fields. The coupling

of their respective magnetic

fields is indicated by the

connection of the color bands.

Figure 10: The Wireless

Electricity power source, left,

is connected to AC power.

The blue lines represent the

magnetic near field induced

by the power source. The

yellow lines represent the

flow of energy from thesource to the Wireless

electricity capture coil,

which is shown powering a

light bulb. Note that this

diagram also shows how the

magnetic field (blue lines)

can wrap around a

conductive obstacle between

the power source and the

capture device.

Wireless Electricity Technology:Wireless Electricity power sources and capture devices

are specially designed magnetic resonators that efficiently transfer power over large distances

via the magnetic near-field. These proprietary source and device designs and the electronic

systems that control them support efficient energy transfer over distances that are many times

the Size of the sources/devices themselves.


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CHAPTER 3. Hardware

3.1 Block Diagram

Figure 11: Block diagram

3.2 Block Diagram Description AC Mains: The law of conservation of energy states that anything that needs to beoperated requires energy for its operation. Thus to operate our circuit we would need some

energy source. This energy is provided by the AC Supply provided in our homes. The voltage

that is provided in our homes is of 50Hz frequency having voltage level of 220 Volts.

Function Generator: The basic requirement of wireless electricity transmission isoperation of circuit at resonance frequency which would increase the range of the magnetic

field in its vicinity so that it can generate magnetic flux in secondary coils with maximum

efficiency. If we would not use resonance frequency then the Transmission of magnetic flux

can be reduced by a factor of upto a million. That is the reason why we have to employ a

function generator to convert the frequency of a AC Main Supply to the resonant frequency

which is decided by the inductance and capacitance which we would be using.

AC mains

Function

Generator Primary Coil Medium

Secondary

coil

Electrical

Equipments


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Primary and Secondary Coils: The primary coil is in the form of a parallel resonantcircuit containing Capacitance and inductance. The Capacitance and inductance generate the

resonance in the coil. When we pass AC Current through our coil then as the current passes

through the inductance a magnetic field is generated in its vicinity. However the magnitude

of magnetic field is very low to use in practical applications. To make it practically viable we

use resonant frequency which would increase the magnitude with which the transmission

takes place by a huge factor of even upto a million times. The resonant frequency is decided

by the capacitance and inductance. The inductance that we are using is of copper. The copper

coil would be having low resistance that would help us to change the current to our will by

adjusting the variable resistance that we would attach in series to the coil. By changing the

value of this resistance, we would be able to control the current.

Medium of Transmission: The basic advantage of the principle of our project is thatthe transmission can take place across different mediums. The magnetic field that we use has

the property to propagate through different materials. Thus we are able to transmit electricity

through different materials, without thinking about the materials that would be there between

the primary coil and secondary coil. The magnetic field can transmit across different

mediums such as brick, wood, cement, etc. Thus the line of sight does not play a role in

propagation of magnetic field.

Electrical Equipments: Various electrical equipments can be operated with theapplication of wireless electricity depending upon the power rating that is required by them.

However there is a limitation on the distance across which they can be operated. The

maximum range across which wireless electricity may be used to run different equipments

can be extended upto a distance of around 5 meters. Further research is going on to increase

the range for the transmission.


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3.3 Circuit Diagram

Figure 12: Circuit Diagram

3.4 Circuit Diagram DescriptionWe are using a parallel LC Circuit. L is used to generate the magnetic flux and C is used to

Condition the sine wave signal. A resistance is connected in series to the parallel LC circuit

which would regulate the current flowing through the circuit. The resistance is set keeping in

mind the current requirement of a circuit and the impedances provided by the parallel LC

circuit.

The inductance of the coil that we are using is found by the formula

L= (0 N2

A)/l

Where L is the inductance of the coil,

0 is the permeability of free spaceN is the number of turns that we are using in our coil.

A is the cross sectional area of the coil

And l is the length of the coil.

Thus, we found L to be equal to 126.2 H. The capacitance that we have used has a value of

0.33 F.

The resonant frequency is found out by the formula

f= 1/2)Thus we have found f to be equal to 1.02 MHz.

The current that we need in the primary coil is calculated on the basis of the efficiency that

we are getting in the transmission and the current that is needed in the secondary coil for the

operation of the electronic component. The current value is adjusted by changing the value of

resistance that we connect in series to the primary coil as per the Ohms Law.

We have XL and XC Connected in Parallel, and R in series so the equivalent resistance of the

circuit is


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Req= R + XL||XC

= R+ (XL. XC )/( XL+XC )

Now XL = 2fL and XC =1/2fC

C=0.33F and L= 126.2H

Thus XL = 808.8 ohms and XC =0.47 ohms

Thus XL||XC =0.469 ohms.

We adjust the value of resistance according to our current requirements. So we set the

resistance at 2 ohms to generate a current of 2 Amperes according to ohms law.

3.5 WorkingWe are providing 220 Volts at 50 Hz frequency to a function generator. The function

generator has a task of converting the frequency of the AC Mains to the resonant frequency

that we require for our operation to take place. The function generator thus converts 50 Hz

frequency signal to 1.02 MHz frequency signal at the voltage level of 15 Volts. This Voltage

Signal sends an AC current to the primary coil generating magnetic flux in the inductance.

The AC currents value is set by then resistance connected in series. The inductance thus

generate a magnetic flux which is the reason by which our primary and secondary coils are

connected .And the voltage induced in the secondary coils is passed through a capacitance of

value 0.33F and a load is connected to this capacitance .If we check using a CRO at the

output of secondary coil, we can measure current induced across the secondary coil. This

current is used to drive our load connected to the secondary winding.

3.5.1 LC Tuned Circuit

An LC circuit, also called a resonant circuit or tuned circuit, consists of an inductor,

represented by the letter L, and a capacitor, represented by the letter C. When connectedtogether, they can act as an electrical resonator, an electrical analogue of a tuning fork,

storing electrical energy oscillating at the circuit's resonant frequency.

LC circuits are used either for generating signals at a particular frequency, or picking out a

signal at a particular frequency from a more complex signal. They are key components in

many electronic devices, particularly radio equipment, used in circuits such as oscillators,

filters, tuners and frequency mixers.
http://en.wikipedia.org/wiki/Inductorhttp://en.wikipedia.org/wiki/Capacitorhttp://en.wikipedia.org/wiki/Resonatorhttp://en.wikipedia.org/wiki/Tuning_forkhttp://en.wikipedia.org/wiki/Resonant_frequencyhttp://en.wikipedia.org/wiki/Electronic_oscillatorhttp://en.wikipedia.org/wiki/Electronic_filterhttp://en.wikipedia.org/wiki/Tuner_%28electronics%29http://en.wikipedia.org/wiki/Frequency_mixerhttp://en.wikipedia.org/wiki/Frequency_mixerhttp://en.wikipedia.org/wiki/Tuner_%28electronics%29http://en.wikipedia.org/wiki/Electronic_filterhttp://en.wikipedia.org/wiki/Electronic_oscillatorhttp://en.wikipedia.org/wiki/Resonant_frequencyhttp://en.wikipedia.org/wiki/Tuning_forkhttp://en.wikipedia.org/wiki/Resonatorhttp://en.wikipedia.org/wiki/Capacitorhttp://en.wikipedia.org/wiki/Inductor


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An LC circuit is an idealized model since it assumes there is no dissipation of energy due to

resistance. For a model incorporating resistance see RLC circuit. The purpose of an LC

circuit is to oscillate with minimal damping, and for this reason their resistance is made as

low as possible. While no practical circuit is without losses, it is nonetheless instructive to

study this pure form to gain a good understanding.

An LC circuit can store electrical energy oscillating at its resonant frequency. A capacitor

stores energy in the electric field between its plates, depending on the voltage across it, and

an inductor stores energy in its magnetic field, depending on the current through it.

If a charged capacitor is connected across an inductor, charge will start to flow through the

inductor, building up a magnetic field around it, and reducing the voltage on the capacitor.Eventually all the charge on the capacitor will be gone and the voltage across it will reach

zero. However, the current will continue, because inductors resist changes in current, and

energy to keep it flowing is extracted from the magnetic field, which will begin to decline.

The current will begin to charge the capacitor with a voltage of opposite polarity to its

original charge. When the magnetic field is completely dissipated the current will stop and

the charge will again be stored in the capacitor, with the opposite polarity as before. Then the

cycle will begin again, with the current flowing in the opposite direction through the

inductor.

The charge flows back and forth between the plates of the capacitor, through the inductor.

The energy oscillates back and forth between the capacitor and the inductor until (if not

replenished by power from an external circuit) internal resistance makes the oscillations die

out. Its action, known mathematically as a harmonic oscillator, is similar to a pendulum

swinging back and forth, or water sloshing back and forth in a tank. For this reason the circuit

is also called a tank circuit. The oscillation frequency is determined by the capacitance and

inductance values used. In typical tuned circuits in electronic equipment the oscillations are

very fast, thousands to millions of times per second.

3.5.1.1 Resonance effect

The resonance effect occurs when inductive and capacitive reactances are equal in absolute

value. The frequency at which this equality holds for the particular circuit is called the

resonant frequency. The resonant frequency of the LC circuit is
http://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/RLC_circuithttp://en.wikipedia.org/wiki/Dampinghttp://en.wikipedia.org/wiki/Electrical_energyhttp://en.wikipedia.org/wiki/Resonant_frequencyhttp://en.wikipedia.org/wiki/Electric_fieldhttp://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Harmonic_oscillatorhttp://en.wikipedia.org/wiki/Pendulumhttp://en.wikipedia.org/wiki/Reactance_%28electronics%29http://en.wikipedia.org/wiki/Electrical_resonancehttp://en.wikipedia.org/wiki/Electrical_resonancehttp://en.wikipedia.org/wiki/Reactance_%28electronics%29http://en.wikipedia.org/wiki/Pendulumhttp://en.wikipedia.org/wiki/Harmonic_oscillatorhttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/Electric_fieldhttp://en.wikipedia.org/wiki/Resonant_frequencyhttp://en.wikipedia.org/wiki/Electrical_energyhttp://en.wikipedia.org/wiki/Dampinghttp://en.wikipedia.org/wiki/RLC_circuithttp://en.wikipedia.org/wiki/Electrical_resistance


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where L is the inductance in henries, and C is the capacitance in farads. The angular

frequency has units ofradians per second.

The equivalent frequency in units ofhertz is

LC circuits are often used as filters; the L/C ratio is one of the factor that determines their

"Q" and so selectivity. For a series resonant circuit with a given resistance, the higher the

inductance and the lower the capacitance, the narrower the filter bandwidth. For a parallel

resonant circuit the opposite applies. Positive feedback around the tuned circuit

("regeneration") can also increase selectivity (see Q multiplier and Regenerative circuit).

Stagger tuning can provide an acceptably wide audio bandwidth, yet good selectivity.

3.5.1.2 Parallel LC circuit

Resonance

Here a coil (L) and capacitor (C) are connected in parallel with an AC power supply. Let R

be the internal resistance of the coil. When XL equals XC, the reactive branch currents are

equal and opposite. Hence they cancel out each other to give minimum current in the main

line. Since total current is minimum in this state the total impedance is maximum.

Resonant frequency given by:

Note that any reactive branch current is not minimum at resonance, but each is given

separately by dividing source voltage (V) by reactance (Z). Hence I=V/Z, as per Ohm's law.

Atfr, line current is minimum. Total impedance is maximum in this state a circuit iscalled a rejecter circuit.
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Belowfr, circuit is inductive. Abovefr, circuit is capacitive.

Impedance

The same analysis may be applied to the parallel LC circuit. The total impedance is then

given by:

and after substitution of and and simplification, gives

.

Note that

but for all other values of the impedance is finite (and therefore less than infinity).

Hence the parallel LC circuit connected in series with a load will act as band-stop filter

having infinite impedance at the resonant frequency of the LC circuit.

3.5.1.3 Applications of resonance effect

1. Most common application is tuning. For example, when we tune a radio to aparticular station, the LC circuits are set at resonance for that particular carrier

frequency.

2. A series resonant circuit provides voltage magnification.3. A parallel resonant circuit provides current magnification.4. A parallel resonant circuit can be used as load impedance in output circuits of RF

amplifiers. Due to high impedance, the gain of amplifier is maximum at resonant

frequency.

5. Both parallel and series resonant circuits are used in induction heating.
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3.5.2 Bridge Rectifier

A diode bridge is an arrangement of four (or more) diodes in a bridge circuit configuration

that provides the same polarity of output for either polarity of input. When used in its most

common application, for conversion of an alternating current (AC) input into direct current a

(DC) output, it is known as a bridge rectifier. A bridge rectifier provides full-wave

rectification from a two-wire AC input, resulting in lower cost and weight as compared to a

rectifier with a 3-wire input from a transformer with a center-tapped secondary winding.

The essential feature of a diode bridge is that the polarity of the output is the same regardless

of the polarity at the input.

3.5.2.1 Basic operation

According to the conventional model of current flow originally established by Benjamin

Franklin and still followed by most engineers today, current is assumed to flow through

electrical conductors from the positive to the negative pole.[2]

In actuality, free electrons in a

conductor nearly always flow from the negative to the positive pole. In the vast majority of

applications, however, the actual direction of current flow is irrelevant. Therefore, in the

discussion below the conventional model is retained.

In the diagrams below, when the input connected to the left corner of the diamond is

positive, and the input connected to the right corner is negative, current flows from the

upper supply terminal to the right along the red (positive) path to the output, and returns to

the lower supply terminal via the blue (negative) path.
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When the input connected to the left corner is negative, and the input connected to the

right corner is positive, current flows from the upper supply terminal to the right along the

red (positive) path to the output, and returns to the lower supply terminal via the blue

(negative) path.

In each case, the upper right output remains positive and lower right output negative. Since

this is true whether the input is AC or DC, this circuit not only produces a DC output from an

AC input, it can also provide what is sometimes called "reverse polarity protection". That is,

it permits normal functioning of DC-powered equipment when batteries have been installed

backwards, or when the leads (wires) from a DC power source have been reversed, andprotects the equipment from potential damage caused by reverse polarity.

Prior to the availability ofintegrated circuits, a bridge rectifier was constructed from "discrete

components", i.e., separate diodes. Since about 1950, a single four-terminal component

containing the four diodes connected in a bridge configuration became a standard commercial

component and is now available with various voltage and current ratings.
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Figure AC, half-wave and full wave rectified signals.

3.5.2.2 Output smoothing

For many applications, especially with single phase AC where the full-wave bridge serves to

convert an AC input into a DC output, the addition of a capacitor may be desired because the

bridge alone supplies an output ofpulsed DC (see diagram to right).

The function of this capacitor, known as a reservoir capacitor (or smoothing capacitor) is to

lessen the variation in (or 'smooth') the rectified AC output voltage waveform from the

bridge. There is still some variation, known as "ripple". One explanation of 'smoothing' is

that the capacitor provides a low impedance path to the AC component of the output,

reducing the AC voltage across, and AC current through, the resistive load. In less technical

terms, any drop in the output voltage and current of the bridge tends to be canceled by loss of

charge in the capacitor. This charge flows out as additional current through the load. Thus the

change of load current and voltage is reduced relative to what would occur without the

capacitor. Increases of voltage correspondingly store excess charge in the capacitor, thus

moderating the change in output voltage / current.
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The simplified circuit shown has a well-deserved reputation for being dangerous, because, in

some applications, the capacitor can retain a lethal charge after the AC power source is

removed. If supplying a dangerous voltage, a practical circuit should include a reliable way to

discharge the capacitor safely. If the normal load cannot be guaranteed to perform this

function, perhaps because it can be disconnected, the circuit should include a bleeder resistor

connected as close as practical across the capacitor. This resistor should consume a current

large enough to discharge the capacitor in a reasonable time, but small enough to minimize

unnecessary power waste.

The capacitor and the load resistance have a typical time constant = RCwhere CandR are

the capacitance and load resistance respectively. As long as the load resistor is large enough

so that this time constant is much longer than the time of one ripple cycle, the above

configuration will produce a smoothed DC voltage across the load.

When the capacitor is connected directly to the bridge, as shown, current flows in only a

small portion of each cycle, which may be undesirable. The transformer and bridge diodes

must be sized to withstand the current surge that occurs when the power is turned on at the

peak of the AC voltage and the capacitor is fully discharged. Sometimes a small series

resistor is included before the capacitor to limit this current, though in most applications the

power supply transformer's resistance is already sufficient. Adding a resistor, or better yet, an

inductor, between the bridge and capacitor can ensure that current is drawn over a large

portion of each cycle and a large current surge does not occur.

Figure
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3.6 TestingThe testing is carried out on the working circuit. We calculate the efficiency of the current in

secondary coil with respect to the primary coil i.e. the efficiency of output according to the

input can be said to be approximately 50% at a distance of 15 cm. We also observe that when

we vary the distance of the secondary coil with respect to primary coil, there is a variation in

the strength of the voltage signal induced. The signal strength is increased when the distance

between the primary and secondary coils reduces. Similarly the signal strength reduces when

the coils are moved apart.


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220V, 50 Hz sine wave signal istaken from the AC mains.

The function generator convertsinput signal to 15V, 1.02MHz signal

This acts as a input signal to LCparallel Circuit

Inductor produces magnetic flux

Magnetic Flux links with thesecondary coil at resonant frequency

Electric field is generated insecondary coil

This Current is used to drive the load

on secondary side


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CHAPTER 4. Wireless Electricity Technology Is More Than.......

4.1 Traditional Magnetic Induction

At first glance, Wireless Electricity technology for power transfer appearsto be traditional magnetic induction, such as is used in power transformers,

where conductive coils transmit power to each other wirelessly, over very

short distances. Inductive charging uses the electromagnetic field to

transfer energy between two objects. 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.

The two coils must be very close together, and may even overlap, but the

coils do not make direct electrical contact with each other. Induction

chargers typically 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 converts it back into electrical current to charge the battery. The

two induction coils in proximity combine to form an electrical transformer

However, the efficiency of the power exchange in traditional magnetic

induction systems drops by orders of magnitude when the distance

between the coils becomes larger than their sizes. In addition to electric

transformers, other devices based on traditional magnetic induction

include rechargeable electric toothbrushes, and inductive charging pads

which require that the object being charged be placed directly on top of, or

very close to, the base or pad supplying the power.

The power exchange efficiency of some induction systems is improved by utilizing resonant

circuits. These so-called resonantly enhanced induction techniques are used in certain medical

implants and high-frequency RFIDs for example. However, to the best of our knowledge,

Wireless Electricity founding technical team was the first to discover that by specially

designing the magnetic resonators, one could achieve strong coupling and highly efficient

energy exchange over distances much larger than the size of the resonator coils, distances very

large compared to traditional schemes.

Figure 14: Magnetic

Induction charging of car

Figure 13: Magnetic Induction

transfer of Energy


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4.2 Radiative Power Transfer

Wireless Electricity technology for power transfer is non-radiative and relies on near-field

magnetic coupling. Many other techniques for wireless power transfer rely on radiative

techniques, either broadcasted or narrow beam (directed radiation) transmission of radio, or

light waves. Broadcasted radiation of radio frequency energy is commonly used for wireless

information transfer because information can be transmitted over a wide are to multiple users.

The power received by each radio or wireless receiver is miniscule, and must be amplified in a

receiving unit using an external power supply. Because the vast majority of radiated power is

wasted into free space, radio transmission is considered to be an inefficient means of power

transfer. Note that while more energy can be supplied to the receiver by "cranking up the

power" of the transmitters in these systems, such high power levels may pose a safety hazard

and may interfere with other radio frequency devices

In addition to radio waves, visible and invisible light waves can also be used to transfer energy.

The sun is an excellent radiative source of light energy, and industry and academia are working

hard to develop photovoltaic technologies to convert sunlight to electrical energy. A laser beam is

a form ofdirectedlight radiation, in which visible or invisible light waves may be formed into a

collimated beam, delivering energy in a targeted way. However, as in the case of directed radio

waves, safe and efficient transmission of laser power requires a clear line of sight between the

transmitter and receiver.

Figure 15: Radiative Power Transfer


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4.4 Tesla's Vision of a Wireless World

In the late 1800's and early 1900's, at the dawn of the electrification of

the modern world, some scientists and engineers believed that using

wires to transfer electricity from every place it was generated to every

place that it could be used would be too expensive to be practical.

Nikola Tesla, one of the most well known of these scientists,

Had a vision for a wireless world in which wireless electric power

and communications would reach around the world, delivering

information and power to ships at sea, factories, and every home on the

planet. Tesla contributed significantly to our understanding of

electricity and electrical systems and is credited with inventing three-

phase AC power systems, induction motors, fluorescent

lamps, radio transmission, and various modes of wireless electric

power transfer. Wireless Electricity technology for power transfer is

different than the technologies proposed by Tesla, but his work is

referenced and acknowledged in the scientific articles published by

Wireless Electricity founding technical team.

Figure 17: Nikola Teslas

Wardenclyffe tower built onLongIsland, NY in 1904.

Thistower was intended toImplement Teslas vision of

transmitting power and

information around the world.

The tower was destroyed in

1917.


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CHAPTER 5.Features and Benefits

5.1 Highly Resonant Strong Coupling Provides High Efficiency over

Distance

Wireless Electricity mode of wireless power transfer is highly efficient over distances

ranging from centimeters to several meters. Efficiency may be defined as the amount of

usable electrical energy that is available to the device being powered, divided by the amount

of energy that is drawn by the Wireless Electricity source. In many applications, efficiency

can exceed 70%. And Wireless Electricity sources only transfer energy when it is needed.

When a Wireless Electricity powered device no longer needs to capture additional energy, the

Wireless Electricity power source will automatically reduce its power consumption to a

power saving "idle" state.

Resonant inductive coupling or electrodynamic induction is the near field wireless

transmission of electrical energy between two coils that are tuned to resonate at the same

frequency. The equipment to do this is sometimes called a resonant or resonance

transformer. While many transformers employ resonance, this type has a highQand is often

air cored to avoid 'iron' losses. The two coils exist as two separate pieces of equipment.

Resonant transfer works by making a coilringwith 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 field (sometimes called evanescent waves),

as all hardware is kept well within the 1/4 wavelength distance they radiate little energy from

the transmitter to infinity.

One of the applications of the resonant transformer is for the CCFL inverter. Another

application of the resonant transformer is to couple between stages of a super-heterodyne

receiver, where the selectivity of the receiver is provided by tuned transformers in the

intermediate-frequency amplifiers. Resonant transformers such as the Tesla coil can generate

very high voltages with or without arcing, and are able to provide much higher current than
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electrostatic high-voltage generation machines such as the Van de Graaff generator. Resonant

energy transfer is the operating principle behind proposed short range wireless electricity.

Using resonance can help efficiency dramatically. If resonant coupling is used, each coil is

capacitively loaded so as to form a tuned LC circuit. If the primary and secondary coils are

resonant at a common frequency, it turns out that significant power may be transmitted

between the coils over a range of a few times the coil diameters at reasonable efficiency.

5.1.1 Energy transfer and efficiency

The general principle is that if a given oscillating amount of energy (for example alternating

current from a wall outlet) is placed into a primary coil which is capacitively loaded, the coil

will 'ring', and form an oscillating magnetic field. The energy will transfer back and forth

between the magnetic field in the inductor and the electric field across the capacitor at the

resonant frequency. This oscillation will die away at a rate determined by the Q factor,

mainly due to resistive and radiative losses. However, provided the secondary coil cuts

enough of the field that it absorbs more energy than is lost in each cycle of the primary, then

most of the energy can still be transferred.

The primary coil forms a series RLC circuit, and the Q factor for such a coil is:

For R=10 ohm,C=1 micro farad and L=10 mH, Q is given as 1000.

Because the Q factor can be very high, (experimentally around a thousand has been

demonstrated with air cored coils) only a small percentage of the field has to be coupled from

one coil to the other to achieve high efficiency, even though the field dies quickly with

distance from a coil, the primary and secondary can be several diameters apart.

5.1.2 Coupling coefficient

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 is between 0 and 1.
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Systems are said to be tightly coupled, loosely coupled, critically coupled or over-coupled.

Tight coupling is when the coupling coefficient is around 1 as with conventional iron-core

transformers. Over-coupling is when the secondary coil is so close that it tends to collapse the

primary's field, and critical coupling is when the transfer in the pass-band is optimal. Loose

coupling is when the coils are distant from each other, so that most of the flux misses the

secondary, in Tesla coils around 0.2 is used, and at greater distances, for example for

inductive wireless power transmission, it may be lower than 0.01.

5.1.3 Power transfer

Because the Q can be very high, even when low power is fed into the transmitter coil, a

relatively intense field builds up over multiple cycles, which increases the power that can be

receivedat resonance far more power is in the oscillating field than is being fed into the

coil, and the receiver coil receives a percentage of that.

5.1.4 Voltage gain

The voltage gain of resonantly coupled coils is proportional to the square root of the ratio of

secondary and primary inductances.

Voltage Gain L2/L1

L1 and L2 are the inductance of primary and secondary coils.

5.1.5 Transmitter coils and circuitry

Unlike the multiple-layer secondary of a non-resonant transformer, coils for this purpose are

often single layer solenoids (to minimise skin effect and give improved Q) in parallel with a

suitable capacitor. Insulation is either absent, with spacers, or low permittivity, low loss

materials such as silkto minimise dielectric losses.

5.1.6 Receiver coils and circuitry

The receiver is a secondary coil connected to a device which is to be worked upon. The

secondary receiver coils are similar designs to the primary sending coils. Running the
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secondary at the same resonant frequency as the primary ensures that the secondary has a low

impedance at the transmitter's frequency and that the energy is optimally absorbed.

To remove energy from the secondary coil, different methods can be used, the AC can be

used directly or rectified and a regulator circuit can be used to generate DC voltage

depending upon the application.

5.2 Energy Transfer via Magnetic Near Field Can Penetrate and Wrap

Around Obstacles

Wireless energy transfer or wireless power is the transmission of electrical energy from a

power source to an electrical load without a conductive physical connection. Wirelesstransmission is useful in cases where interconnecting wires are inconvenient, hazardous, or

impossible. The problem of wireless power transmission differs from that of wireless

telecommunications, such as radio. In the latter, the proportion ofenergy received becomes

critical only if it is too low for the signal to be distinguished from the background noise. With

wireless power, efficiency is the more significant parameter. A large part of the energy sent

out by the generating plant must arrive at the receiver or receivers to make the system

economical.

The magnetic near field has several properties that make it an excellent means of transferring

energy in a typical consumer, commercial, or industrial environment. Most common building

and furnishing materials, such as wood, gypsum wall board, plastics, textiles, glass, brick,

and concrete are essentially "transparent" to magnetic fieldsenabling Wireless Electricity

technology to efficiently transfer power through them. In addition, the magnetic near field

has the ability to "wrap around" many metallic obstacles that might otherwise block the

magnetic fields.

An electric current flowing through a conductor carries electrical energy. When an electric

current passes through a circuit there is an electric field in the dielectric surrounding the

conductor; magnetic field lines around the conductor and lines of electric force radially about

the conductor.

In a direct current circuit, if the current is continuous, the fields are constant; there is a

condition of stress in the space surrounding the conductor, which represents stored electric
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and magnetic energy, just as a compressed spring or a moving mass represents stored energy.

In an alternating current circuit, the fields also alternate; that is, with every half wave of

current and of voltage, the magnetic and the electric field start at the conductor and run

outwards into space with the speed of light. Where these alternating fields impinge on

another conductor a voltage and a current are induced.

Any change in the electrical conditions of the circuit, whether internal or external involves a

readjustment of the stored magnetic and electric field energy of the circuit, that is, a so-called

transient. A transient is of the general character of a condenser discharge through an

inductive circuit. The phenomenon of the condenser discharge through an inductive circuit

therefore is of the greatest importance to the engineer, as the foremost cause of high-voltage

and high-frequency troubles in electric circuits.

Electromagnetic induction is proportional to the intensity of the current and voltage in the

conductor which produces the fields and to the frequency. The higher is the frequency, the

more intense the induction effect. Energy is transferred from a conductor that produces the

fields (the primary) to any conductor on which the fields impinge (the secondary). A part of

the energy of the primary conductor passes inductively across space into secondary conductor

and the energy decreases rapidly along the primary conductor.

A high frequency current does not pass for long distances along a conductor but rapidly

transfers its energy by induction to adjacent conductors. Higher induction resulting from the

higher frequency is the explanation of the apparent difference in the propagation of high

frequency disturbances from the propagation of the low frequency power of alternating

current systems. The higher the frequency, the more preponderant become the inductive

effects that transfer energy from circuit to circuit across space. The more rapidly the energy

decreases and the current dies out along the circuit, the more local is the phenomenon.

The flow of electric energy thus comprises phenomena inside of the conductor and

phenomena in the space outside of the conductorthe electric fieldwhich, in a continuous

current circuit, is a condition of steady magnetic and dielectric stress, and in an alternating

current circuit is alternating, that is, an electric wave launched by the conductor to become

far-field electromagnetic radiation traveling through space with the speed of light.
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In electric power transmission and distribution, the phenomena inside of the conductor are of

main importance, and the electric field of the conductor is usually observed only incidentally.

Inversely, in the use of electric power for radio telecommunications it is only the electric and

magnetic fields outside of the conductor that is electromagnetic radiation, which is of

importance in transmitting the message. The phenomenon in the conductor, the current in the

launching structure, is not used.

The electric charge displacement in the conductor produces a magnetic field and resultant

lines of electric force. The magnetic field is a maximum in the direction concentric, or

approximately so, to the conductor. That is, a ferromagnetic body tends to set itself in a

direction at right angles to the conductor. The electric field has a maximum in a direction

radial, or approximately so, to the conductor. The electric field component tends in a

direction radial to the conductor and dielectric bodies may be attracted or repelled radially to

the conductor.

The electric field of a circuit over which energy flows has three main axes at right angles

with each other:

1. The magnetic field, concentric with the conductor.2. The lines of electric force, radial to the conductor.3. Thepower gradient, parallel to the conductor.

Where the electric circuit consists of several conductors, the electric fields of the conductors

superimpose upon each other, and the resultant magnetic field lines and lines of electric force

are not concentric and radial respectively, except approximately in the immediate

neighborhood of the conductor. Between parallel conductors they are conjugate of circles.

Neither the power consumption in the conductor, nor the magnetic field, nor the electric field,are proportional to the flow of energy through the circuit.

However, the product of the intensity of the magnetic field and the intensity of the electric

field is proportional to the flow of energy or the power, and the power is therefore resolved

into a product of the two components i and e, which are chosen proportional respectively to

the intensity of the magnetic field and of the electric field. The component called the current

is defined as that factor of the electric power which is proportional to the magnetic field, and
http://en.wikipedia.org/wiki/Concentrichttp://en.wikipedia.org/wiki/Vector_%28geometric%29http://en.wikipedia.org/wiki/Parallel_%28geometry%29http://en.wikipedia.org/wiki/Conjugate_element_%28field_theory%29http://en.wikipedia.org/wiki/Conjugate_element_%28field_theory%29http://en.wikipedia.org/wiki/Parallel_%28geometry%29http://en.wikipedia.org/wiki/Vector_%28geometric%29http://en.wikipedia.org/wiki/Concentric


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the other component, called the voltage, is defined as that factor of the electric power which

is proportional to the electric field.

In radio telecommunications the electric field of the transmit antenna propagates through

space as a radio wave and impinges upon the receive antenna where it is observed by its

magnetic and electric effect. Radio waves, microwaves, infrared radiation, visible light,

ultraviolet radiation, X rays and gamma rays are shown to be the same electromagnetic

radiation phenomenon, differing one from the other only in frequency of vibration.

5.2.1 Electrostatic induction method

Electrostatic or capacitive coupling is the passage of electrical energy through a dielectric. In

practice it is an electric field gradient or differential capacitance between two or more

insulated terminals, plates, electrodes, or nodes that are elevated over a conducting ground

plane. The electric field is created by charging the plates with a high potential, high

frequency alternating current power supply. The capacitance between two elevated terminals

and a powered device form a voltage divider.

The electric energy transmitted by means of electrostatic induction can be utilized by a

receiving device, such as a wireless lamp. Tesla demonstrated the illumination of wireless

lamps by energy that was coupled to them through an alternating electric field.

"Instead of depending on electrodynamic induction at a distance to light the tube . . . [the]

ideal way of lighting a hall or room would . . . be to produce such a condition in it that an

illuminating device could be moved and put anywhere, and that it is lighted, no matter where

it is put and without being electrically connected to anything. I have been able to produce

such a condition by creating in the room a powerful, rapidly alternating electrostatic field.

For this purpose I suspend a sheet of metal a distance from the ceiling on insulating cords and

connect it to one terminal of the induction coil, the other terminal being preferably connected

to the ground. Or else I suspend two sheets . . . each sheet being connected with one of the

terminals of the coil, and their size being carefully determined. An exhausted tube may then

be carried in the hand anywhere between the sheets or placed anywhere, even a certain

distance beyond them; it remains always luminous."

The principle of electrostatic induction is applicable to the electrical conduction wireless

transmission method.
http://en.wikipedia.org/wiki/Radio_wavehttp://en.wikipedia.org/wiki/Electromagnetic_radiationhttp://en.wikipedia.org/wiki/Electromagnetic_radiationhttp://en.wikipedia.org/wiki/Capacitive_couplinghttp://en.wikipedia.org/wiki/Dielectrichttp://en.wikipedia.org/wiki/Differential_capacitancehttp://en.wikipedia.org/wiki/Nikola_Teslahttp://en.wikipedia.org/wiki/High_frequencyhttp://en.wikipedia.org/wiki/Electrostatic_fieldhttp://en.wikipedia.org/wiki/Electrostatic_fieldhttp://en.wikipedia.org/wiki/Electrostatic_fieldhttp://en.wikipedia.org/wiki/High_frequencyhttp://en.wikipedia.org/wiki/Nikola_Teslahttp://en.wikipedia.org/wiki/Differential_capacitancehttp://en.wikipedia.org/wiki/Dielectrichttp://en.wikipedia.org/wiki/Capacitive_couplinghttp://en.wikipedia.org/wiki/Electromagnetic_radiationhttp://en.wikipedia.org/wiki/Electromagnetic_radiationhttp://en.wikipedia.org/wiki/Radio_wave


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In some cases when small amounts of energy are required the high elevation of the

terminals, and more particularly of the receiving-terminal D', may not be necessary, since,

especially when the frequency of the currents is very high, a sufficient amount of energy may

be collected at that terminal by electrostatic induction from the upper air strata, which are

rendered conducting by the active terminal of the transmitter or through which the currents

from the same are conveyed."

5.3 Non-Radiative Energy Transfer is Safe for People and Animals

Wireless Electricity technology is a non-radioactive mode of energy transfer, relying instead

on the magnetic near field. Magnetic fields interact very weakly with biological organisms

people and animalsand are scientifically regarded to be safe. Professor Sir John Pendry of

Imperial College London, a world renowned physicist, explains: "The body really responds

strongly to electric fields, which is why you can cook a chicken in a microwave. But it

doesn't respond to magnetic fields. As far as we know the body has almost zero response to

magnetic fields in terms of the amount of power it absorbs." Evidence of the safety of

magnetic fields is illustrated by the widespread acceptance and safety of household magnetic

induction cook tops.

Through proprietary design of the Wireless Electricity source, electric fields are almost

completely contained within the source. This design results in levels of electric and

magnetic fields which fall well within regulatory guidelines. Thus Wireless Electricity

technology doesn't give rise to radio frequency emissions that interfere with other electronic

devices, and is not a source of electric and magnetic field levels that pose a risk to people or

animals.

Limits for human exposure to magnetic fields are set by regulatory bodies such as the FCC,

ICNIRP, and are based on broad scientific and medical consensus. Wireless Electricity

technology is being developed to be fully compliant with applicable regulations regarding

magnetic fields and electromagnetic radiation.

5.4 Scalable Design Enables Solutions from milliwatts to Kilowatts

Wireless Electricity systems can be designed to handle a broad range of power levels. The

benefits of highly efficient energy transfer over distance can be achieved at power levels


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ranging from milliwatts to several kilowatts. This enables Wireless Electricity technology to

be used in applications as diverse as powering a wireless mouse or keyboard (mill watts) to

recharging an electric passenger vehicle (kilowatts). Wireless Electricity technology operates

in a "load following" mode, transferring only as much energy as the powered device requires.

5.5 Flexible Geometry Allows Wireless Electricity Devices to be embedded

Into OEM Products

Wireless Electricity technology is being designed so that it can be easily embedded into a

wide variety of products and systems. The physics of resonant magnetic coupling enables

Wireless Electricity engineers to design power sources and devices of varying shapes and

sizes, to match both the packaging requirements and the power transfer requirements in

a given OEM application. Wireless Electricity has designed power capture devices compact

enough to fit into a cell phone.


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CHAPTER 6: Questionnaire

The concept being so new and innovative brings in so many questions. Hereafter, some

questions are being answered on the basis of study done on the topic and relevant topics.

Is Wireless Electricity technology safe?

Human beings or other objects placed between the transmitter and receiver do not hinder

the transmission of power. Wireless Electricity technology is a non-radiative mode of energy

transfer, relying instead on the magnetic near field. Magnetic fields interact very weakly

with biological organismspeople and

Animalsand are scientifically regarded to be safe. Wireless Electricity products are being

designed to comply with applicable safety standards and regulations.

How much power can be transferred?

Till now, Scientists has been able to transfer more than 60W power. The technology by itself

is capable of scaling from applications requiring milliwatts to those requiring several

kilowatts of power.

Over what distance can Wireless Electricity technology transfer power?

Wireless Electricity technology is designed for "mid-range" distances, which we consider to

be anywhere from a centimeter to several meters. The actual operating range for a given

application is determined by many factors, including power source and capture device sizes,

desired efficiency, and the amount of power to be transferred.

How efficient is Wireless Electricity technology?

The power transfer efficiency of a Wireless Electricity solution depends on the relative sizes

of the power source and capture devices, and on the distance between the devices. Maximum

efficiency is achieved when the devices are relatively close to one another, and can exceed

80%.


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What's the Future of Wireless Electricity?

MIT's Wireless Electricity is only 40 to 45% efficient and according to Soljacic, they have

to be twice as efficient to compete with the traditional chemical batteries. The team's

next aim is to get a robotic vacuum or a laptop working, charging devices placed anywhere in

the room and even robots on factory floors. The researchers are also currently working on

the health issues related to this concept and have said that in another three to five years

time, they will come up with a Wireless Electricity system for commercial use.


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CHAPTER 7: Conclusion

The transmission of power without wires is not a theory or a mere possibility, it is now a

reality. The electrical energy can be economically transmitted without wires to specific

terrestrial distance. Many researchers have established in numerous observations,

experiments and measurements, qualitative and quantitative.

Dr. N. Tesla is the pioneer of this invention. Wireless transmission of electricity have

tremendous merits like high transmission integrity and Low Loss (90 97% efficient) and

can be transmitted to anywhere in the globe and eliminate the need for an inefficient, costly,

and capital intensive grid of cables, towers, and substations. The system would reduce the

cost of electrical energy used by the consumer and get rid of the landscape of wires, cables,

and transmission towers. It has negligible demerits like reactive power which was found

insignificant and biologically compatible. It has a tremendous economic impact to human

society.


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Appendix

A.References http://www.Wireless Electricity.com http://www.Wireless Electricitypower.com http://www.sciencemag.org/cgi/data/1143254/DC1/1 http://www.sciencemag.org/cgi/content/abstract/1143254 http://www.witric.com/2007/06/10/Wireless Electricity-impact/ An article published in the Science Magazine as "Wireless Power Transfer via

strongly Coupled Magnetic Resonances by Andre kurs, Science 317, 83(2007); Dol:

10.1126/ science.1143254.

"Efficient Non-Radiative Midrange Energy Transfer" by Aristeidies karalis, MarlinSoljacic.


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B. List of Diagrams Page No.Figure 1. Nikola Tesla..9

Figure 2: Consumer Applications...10

Figure 3: Industrial Applications....11

Figure 4: Future Applications.....11

Figure 5: An illustration representing the earth's magnetic field...12

Figure 6:As electric current, I flow in the circuit it give rise to a magnetic field, which wrap

around wire and when current is reversed magnetic field also get

reversed12

Figure 7: The blue lines represent the magnetic field when current flows through a coil and

current is reversed, magnetic field reversed. ....12

Figure 8: An electric transformer is a device that uses magnetic induction to transfer energy

from its primary winding to its secondary winding, without the windings being connected to

each other. It is used to "transform" AC current at one voltage to AC current at a different

voltage. ..13

Figure 9: Two idealized resonant magnetic coils, shown in yellow. The blue and red color

bands illustrate their magnetic fields. The coupling of their respective magnetic fields is

indicated by the connection of the color bands. ...14

Figure 10: The Wireless Electricity power source, left, is connected to AC power. The blue

lines represent the magnetic near field induced by the power source. The yellow lines

represent the flow of energy from the source to the Wireless electricity capture coil, which is

shown powering a light bulb. Note that this diagram also shows how the magnetic field (blue

lines) can wrap around a conductive obstacle between the power source and the capture

device. ...14


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Figure 11: Block diagram...15

Figure 12: Circuit Diagram.....17

Figure 13: Magnetic Induction transfer of Energy..20

Figure 14: Magnetic Induction charging of car...20

Figure 15: Radiative Power Transfer..21

Figure 16: MRI...22

Figure 17:Nikola Teslas Wardenclyffe tower built on LongIsland, NY in 1904. Thistower

was intended to implement Teslas vision of transmitting power and information around the

world. The tower was destroyed in 1917.....22


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C.Detail of Components used Primary and Secondary Coils- identical copper coils with 44 turns and L=126.2H. 0.33uF Capacitor. Function generator. CRO Connecting wires & CRO Probes Multimeter


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