Witricity Sushila

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Sunday, April 15, 20121


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Witricity is nothing butwireless electricity.

Transmission of electrical energy from one

object to another without the use of wires iscalled as Witricity.

Because of Witricity some of the devices won't

require batteries to operate.

Sunday, April 15, 2012 2wireless electricity


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Sunday, April 15, 2012wireless electricity 3

.

The story started late one night

a few years ago. It was probably

the sixth time that month that

MIT Professor Marin Soljacic

was awakened by his mobile

phone beeping battery low. At

that time it occurred to him that

there is electricity wired all

through his house, office-everywhere. He think about- how

it is possible to use electricity

without using wires

Eureka! Coupled Resonators


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Sunday, April 15, 2012

4

wireless electricity

basics

electricity

magnetism

Energycoupling

Magneticinduction

Electro

magnetism

Resonant

magnetic

coupling

resonance


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Electricityis a general term thatencompasses a variety ofphenomena resulting from the

presence and flow of electriccharge.

Magnetism is a force that acts at adistance due to a magnetic field.

This field is caused by movingelectrically charged particles or isinherent in magnetic objects suchas magnet.



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Electromagnetic inductionis the

production of voltage across a

conductor moving through a

magnetic field.

Electromagnetismis one of the

four fundamental interactions of

nature, along with strong

interaction, weak interaction and

gravitation. It is the force thatcauses the interaction between

electrically charged particles; the

areas in which this happens are

called electromagnetic fieldsEnergy/Power Coupling: Energy

coupling occurs whenanenergy

source has a means of

transferring energy to another

object


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Resonance :is the tendency of asystem to oscillate with largeramplitude at some frequencies

than at others. These are knownas the system's resonantfrequencies (or resonancefrequencies). At thesefrequencies, even small periodic

driving forces can produce largeamplitude oscillations

Resonant Magnetic Coupling:Magnetic coupling occurs whentwo objects exchange energythrough their varying oroscillating magnetic fields.Resonant coupling occurs whenthe natural frequencies of the twoobjects are approximately thesame.Sunday, April 15, 2012wireless electricity 7


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The Transfer of Electricity from one place to another withoutwires is known as Witricity.

There is witricity power sources(transmitter) andcapture

devices(receiver).

Power source provides power to the devices where as capture

devicecaptured it to work.

Power source and capture devices are specially designedmagnetic resonators.

Magnetic resonators efficiently transfer power over large

distance via the magnetic near-field.


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Near field is a wireless transmissiontechnique over distances comparable to or

a few times the diameter of devices.

Near field is usually magnetic.

Near field energy is non radiative .but some

radiative and resistive losses will occur.



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Two resonant objects of the same resonantfrequency tend to exchange energy.

Itexchange energy strongly ,whileinteracting weakly with living beings and

other environmental objects.

Coupled resonators are said to be operate in

strongly coupled regimeto avoid material

absorption and radiative loss.Sunday, April 15, 2012wireless electricity 10



Strength of interaction is very high.

Coupling constantg>=1

Energy transfer is very efficient.

The rate of energy transfer is substantiallyhigher than rate of energy lose.



The first experiment of witricity, the concept of

wireless electricity, was conducted in the year 2006, by

researchers from Massachusetts Institute ofTechnology. The Assistant Professor of this team of

researchers was Marin Soljacic.

2007: A physics

research group, led by

Prof. Marin Soljacic,at MIT,

wirelessly power a 60Wlight bulb with 40%

efficiency at a 2 meters

(6.6 ft) distance using two

60 cm-diameter coils



Power source is connected to ac

power.

Bulb is connected to capture device.

Blue lines represent the magnetic

near field induced by the power

source.

Yellow lines represent the flow of

energy from the source to the capture

coil.

This powers light bulb.

The magnetic field can wrap

around the obstacle between power

source and capture coil.


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Traditional magnetic induction.

Radiative power transfer.

Teslas vision of a wireless world.



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Used in power transformers.

conductive coils transmit power to each other

wirelessly, over very short distance.


An electric tooth

brush uses

traditional magnetic

induction to

recharge its

batteries


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Radio frequency energy is used for wireless

power transfer.

Radiated power is wasted into free space Need line of sight.

Harmful.


Microwave oven utilizes

radiation to cook foods


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Nikola Tesla the most well

known scientist had a visionof wireless world.

In which wireless electric

power and communicationwould reach around the

world, delivering information

and power.


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Witricitys Technology Technology BenefitHighly resonant strong coupling High efficiency over distance

Energy transfer via magnetic near

field

Can penetrate and wrap around

obstacles

Non radiative energy transfer Safe for living beings and otherenvironmental objects

Flexible geometry Device that can fit into OEM

(original equipmentmanufactures)products

Scalable design From Mw to kW


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Direct wireless power-within the range of

witricity power source

Automatic wireless charging- both in and out

of range of its witricity power source.



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Automatic wireless charging

of mobile electronics in

home, car, office,...while

devices are in use and

mobile.

Direct wireless powering of

stationary

deviceseliminating

expensive custom wiring,unsightly cables and wall-

wart power supplies.

Sunday, April 15, 2012 25wireless electricity


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Robots, packagemachinery, assemblymachinery, machinetools.

Direct wireless powerand communicationinterconnections atpoints of use in harshenvironments.

Direct wireless powerfor wireless sensorsand actuators,eliminating the needfor expensive powerwiring or batteryreplacement anddisposal.



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Automatic wireless

charging for existingelectric vehicle classes:golf carts, industrialvehicles.

Automatic wirelesscharging for futurehybrid and all-electricpassenger and

commercial vehicles, athome, in parkinggarages, at fleet depots,and at remote kiosks.



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Direct wireless powerinterconnections and

automatic wirelesscharging for implantable

medical devices .

Automatic wireless

charging and for high tech

military systems.

Direct wireless powering

and automatic wireless

charging of smartcards.

Direct wireless poweringand automatic wireless

charging ofconsumer

Appliance, mobile robots,

etc.



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No need of line of sight.

No need of power cablesand batteries.

Does not interfere with

radio waves.


Wastage of power issmall .

Negative health

implications.

Highly efficient than

electromagnetic

induction

Less costly.


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Wireless power transmission can be

possible only in few meters.

Efficiency is only about 40%.



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Teams next aim is to get a robotic vacuum

or a laptop working, charging devices

placed any where in the room and evenrobots on factory floors.

In another 3 to 5 years time. they will come

up with a witricity for commercial use.



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