2. Content
2
• What is WiTricity?
• History of Wireless power
• Experimental design of WiTricity technology
• WiTricity basics
• Wireless energy transfer techniques
• Working principle of WiTricity
• Is WiTricity safe?
• WiTricity Applications
• Benefits and Advantages
• Limitations
• Conclusion
• References
3. What is WiTricity
3
• WiTricity is nothing but Wireless Electricity.
• Transmission of electrical energy from one object to
another without the use of wire is called WiTricity.
• Because of the wiTricity, some of the devices won’t
require batteries to operate.
Cables are going to bereplaced byWiTricity
4. We human love electricity !
And to power our electronics devices we buy..
..
Which ends as…..
4
Which ends as…..
5. Why not wires??
• As perstudies,mostelectricalenergytransferis throughwires.
• Mostof theenergyloss is duringtransmission
• On an average, more than30%
• In India, it exceeds by40%
Why not batteries??
Estimatedthat40 millionbatteriesperyearaddtothee-waste
burden.
Andof courseitsnota goodsign.
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6. History of Wireless power
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In late 1890’s, Sir Nikola Tesla proposed the method of
wireless power transmission.
In 1899, he was able to light 200 lamps over 25 miles away
without using wires.
As it was in radiative mode, most of the power was wasted
and less efficiency about 15% only.
In 2005, Dave Gerding coined the term WiTricity which is
being used today.
Wireless elecTricity
7. Built the wardenclyffe
tower(Tesla tower) which could
broadcast power wirelessly using
far-field techniques. Called off as
it radiated power into
surroundings raising issues of
power loss
Power theft
Health concerns
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8. The forgotten invention is reborn in
2007
8
The idea of wireless
electricity has been
around since the early
days of the Tesla coil.
But thanks to a group of MIT
scientists, "WiTricity" (as these
scientists call it) is now one
step closer to practical reality.
In 2007,6 MIT members headed
by Marin Soljacic were able to
successfully transmit power to a
bulb within a distance of 2m ata
freq of 9.9MHz .
They use concepts of non
radiative mid range energy
transfer, Resonance,
inductive coupling.
Efficiency at that point was
just approximately 43%.
9. Experimental design
Experimental scheme consists of two Self-resonant
coils. One coil (source coil) is coupled inductively to an
oscillating circuit; the other (device coil) is coupled
inductively to a resistive load. Self-resonant coils rely
on the interplay between distributed inductance and
distributed capacitance to achieve resonance.
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10. WiTricity Technology
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Power source is connected to acpower.
Bulb is connected to capture device.
Bluelinesrepresentthemagneticnearfield
induced bythe powersource.
Yellow lines represent the flow ofenergy
from the source to the capturecoil.
Thispowerlightsupthe bulb.
Themagneticfieldcanwraparound theobstacle
between powersource andcapture coil.
13. Fundamentals
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• Electricityis a general term that
encompasses a variety of phenomena
resulting from the presence and flow of
electriccharge.
• Magnetismis a force that acts at a
distance due to a magnetic field. This field
is caused by moving electrically charged
particles or is inherent in magnetic
objects such as magnet.
14. • Electromagneticinduction isthe
production of voltage across a
conductor moving through a
magneticfield.
• Energy/Power Coupling: Energy
coupling occurs when an energy
source has a means oftransferring
energy to anotherobject.
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15. Typesof wireless energy transfer
techniques
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Short
range–
Inductive
coupling
Mid range–
Resonance
Inductive
coupling
Long range-
Electromagetic
Wave Power
Transfer
16. How does Inductive Couplingwork??
16
Inductivecouplingworksontheprinciplesof
electromagnetism:
“When a current (electricity) passes through a
wire,itgeneratesa magneticfieldperpendicularto
thewire.
Whena wireis inproximitytoa magneticfield,it
generates a current in thatwire.”
Magneticfields decay quickly , makinginductive
couplingeffective only at very shortranges.
• Wireless Charging Pad(WCP),electricbrushesare
someexamples
• On a WCP,thedevicesaretobekept,batterywill
be automaticallycharged.
17. How does Resonant Induction work??
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• Resonant induction still usesthe
sameprinciplesas magnetic
induction(magneticfieldsto
transfercurrent), but it uses
resonance to increase the range
at whichthetransfercan
efficientlytake place.
• “Resonance", a phenomenon that
causes an object to vibrate when
energy ofa certainfrequency is
applied.
WiTricityis based on Resonant Inductive coupling..
18. Long range: Far field powertransfer
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• Far-fieldmethod achieves longer ranges whichis much
greater than the diameter ofdevice.
• These far-fieldtype techniques includeRadio &
Microwave Power Transmission Techniques &LASER
Techniques.
19. How WiTricity works
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1)Power from mains to antenna, whichis made ofcopper.
2) Antenna resonatesata frequencyof10MHz, emitting
electromagnetic waves.
3) 'Tails'of energy from antenna'tunnel' upto 2.5m (8.2ft).
4) Electricitypicked upbylaptop's antenna, whichmust also be
resonating at10MHz. Energyused to re-charge device.
5)Energynot transferredtolaptop re-absorbedbysource
antenna.People/otherobjectsnotaffectedasnotresonatingat
10MHz.
22. Is WiTricity Technologysafe?
22
• WiTricity’stechnologyis a non-
radiativemode of energy
transfer, relyinginsteadonthe
magnetic nearfield.
• Magneticfieldsinteractvery
weaklywithbiological
organisms—peopleand
animals—andarescientifically
regarded to be safe.
• WiTricityproductsarebeing
designedtocomplywith
applicablesafetystandardsand
regulations.
23. WiTricity Applications
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Consumer Electronics
• Automatic wireless charging of mobile electronics in home, cars, offices.
• Mobile phones, Laptops, Game controllers etc.
Industrial Applications
• Direct wireless power and communication interconnections at points of usein
harshenvironments.
• In Drilling, Mining, Underwateretc.
Transportation
• Automatic wireless charging for existing electric vehicleclasses.
• In Golf carts, Carsetc.
Other Applications( Medical devices, Military applications
and Robots)
25. Benefits ofWiTricity
It will make products:
MoreConvenient:
• -No manual recharging or changingbatteries.
• -Eliminate unsightly, unwieldy and costly powercords.
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MoreReliable:
• -Never run out of batterypower.
More EnvironmentallyFriendly:
• -Reduce use of disposablebatteries.
• -Use efficient electric ‘grid power’ directly.
26. Advantages
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• Safe, fairly efficient, goodrange
• Boonforthedeviceswhichusesmidrangepower
• No need of line ofsight.
• Noneedof powercablesandbatteries.
• Ewaste is eliminated.
• More secure, no risk of getting shocked.
• Maintenance cost will be saved.
27. Limitations
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• Transmissions possible only in fewmeters.
• Possibility of “energytheft”.
• Efficiency decreases withdistance.
• Theresonanceconditionshouldbesatisfiedandifany
errorexists,thereisnopossibilityofpowertransfer.
28. Conclusion
Think that the city will be covered with
WPT hot spots, just like wireless internet,
there will be no need of charging batteries,
or carrying adaptors all around.
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29. Future of Witricity
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If we apply this idea to the whole city, we might not have to use any wired
cable. Moreover, in the future, it would save the material cost, and
“WE CAN SAVE THE WORLD,YEAH!!!”
30. References
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• Peter Vaessen,” Wireless Power Transmission”, Leonardo Energy,
September 2009.
• Richard M. Dickinson, and Jerry Grey, “Lasers for Wireless Power
Transmission”.
• White Paper on Solar Power Satellite (SPS) Systems, URSI, September
2006.
• Richard M. Dickinson, and Jerry Grey, “Lasers for Wireless Power
Transmission”.
• T. R. Robinson, T. K. Yeoman and R. S. Dhillon, “Environmental impact of
high power density microwave beams on different atmospheric layers”.
• C.C. Leung, T.P. Chan, K.C. Lit, K.W. Tam and Lee Yi Chow, “Wireless
Power Transmission and Charging Pad”.
• David Schneider, “Electrons unplugged”, IEEE Spectrum, May 2010.
