The presentation discusses the history and techniques of wireless electricity transmission. It describes Nikola Tesla's early experiments with wireless power in the 1890s using resonant inductive coupling. More recently, MIT researchers demonstrated mid-range wireless power transfer using coupled resonator theory, achieving 43% efficiency over 2 meters. Applications could include wirelessly charging electric vehicles and powering devices without batteries. Long-range microwave transmission could one day transmit solar power from satellites to Earth. While promising, wireless power faces challenges of efficiency over distance, health concerns, and high implementation costs.

1. PRESENTATION BY:-
ASHISH RAJ SAHU
ROLL NO-1112232015
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2. Why do we need wireless
electricity???
The ever increasing power demand
The need of electricity in every nook and
corner of the world
The demand of eco-friendly power
Requirement of efficient and reliable power
To reduce dependence on wires and batteries
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4. 4

5. In the year 1893,Nikola Tesla
proposed the method of
wireless transmission of electric
power
One of the greatest breakthroughs
of science at that time
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6. Built the wardenclyffe 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
A dream crashes……
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7. Types of wireless energy transfer
techniques are:-
Short range– Inductive coupling
Mid range– Resonance Inductive
coupling
Long range-
Microwave Transmission
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8. Uses electromagnetic induction
concept-A term for the
interdependence of time-varying
electric and magnetic fields
Wireless electricity makes use of
the concept-
“Oscillating electric field produces
magnetic field and oscillating
magnetic field produces electric
field”.
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10. Resonant Inductive Coupling
Uses almost the same
concept as Inductive
coupling just that the coils
operate at resonant
frequency leading to
efficient transfer of energy
over a larger distance
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11. D i f f e r e n t F r e q u e n c y
Resonance
Property of systems to operate at higher amplitudes at purticular
frequencies known as resonant frequencies than at others.
When 2 objects operate at same resonant frequency they transfer energy
efficiently between them without interfering with the off resonant objects.
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12. The glass which was having the resonant frequency
as of the singer’s voice accumulated sufficient
energy to explode eventually
D i f f e r e n t F r e q u e n c y
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14. The Witricity Team
In 2007,6 MIT members
headed by Marin Soljacic were
able to successfully transmit
power to a bulb within a
distance of 2m at a freq of
9.9MHz using concepts of
non radiative mid range energy
transfer
Resonance
inductive coupling
Efficiency at that point was just
approximately 43%
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15. Block diagram for witricity mechanism
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16. Circuit diagram for witricity
demonstration
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17. Coupled mode theory for range & rate of coupling
In the coupled mode theory system with 2 resonators follow the below 2 equations:-
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18. The solution of the equation show that at exact resonance
at: ωd= ωs and Γs=Γd
ad(t) depends on only geometry and distance between them
provided k/Γ>>1.
The solution of the equation show that at exact
resonance at: ω1=ω2 and Γ1=Γ2
the normal modes of the combined system are split
by 2κ.
 The energy exchange between the two objects takes place
in time Pi/κ and is nearly perfect, apart for losses, which are
minimal when the coupling rate is much faster than all loss
rates (κ>> Γs, d).
 The energy exchange between the two objects
takes place in time Pi/κ and is nearly perfect, apart
for losses, which are minimal when the coupling
rate is much faster than all loss rates (κ>> Γ1, 2).
 The desired optimal regime {κ/sqrt (Γs,d)>>1} is called
“Strong-Coupling” regime. There is No exchange of
Energy, unless κ/Γ>>1 is true.
 The desired optimal regime {κ/sqrt (Γ1,2)>>1} is
called “Strong-Coupling” regime. There is No
change in Energy, unless κ/Γ>>1 is true.
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19. Wireless electricity in our daily life
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20. Efficiency chart of witricity
It is observed that efficiency decreases with increase
in distance between source coil and load coil
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21. Applications of Witricity(short range and mid range)
1.DIRECT WIRELESS POWER
No device would need wires
For TVs, toasters or any form of immobile
electronic devices.
2. AUTOMATIC WIRELESS CHARGING
Device with rechargeable batteries
charges itself.
For any form of mobile devices .
3.INDUSTRIAL
would be free of heavy installation of
wires and devoid of any hazardous
electric shock incidents.
4.TRANSPORTATION
Could charge an electric car or automobile.
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22. Types of Long range/Far field
transmission techniques
Radio frequency Transmission
extracts small quantities of energy in the
range 902 and 928 MHz
Disadvantage—interference caused by
metal surfaces
Laser Transmission
Highly directional and coherent
Inefficient for wireless power
transmission
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23. Microwave Transmission
Aims at higher power transfer over longer
distances practically in the range of some miles
Requires a microwave source, antenna and
rectenna
operates in the frequency range of 1-40GHz
operates at the highest efficiency at 2.45GHz
Steps:
1.conversion of electrical to microwave energy
2.Capturing of microwave beams by Rectenna
3.conversion of microwave to electrical energy
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24. Block diagram for microwave power
transmission model
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25. Major components of the model
Microwave generator:
Microwave power sources used like Klystron,
magnetron, TWT or GaAs MESFETs
Output power is controlled by electronic
circuits.
Magnetron is most preferred at 2.45 GHz
Transmitting antenna:
Has the responsibility of transmitting power.
Patch, Microstrip, parabolic dish or slotted
waveguide antenna may be used.
Rectenna:
Consists of a antenna ,rectifying diodes and low
pass filter.
Rectenna area has to be large.
Important for receiving microwave power 25

26. Ontroller Rectenna block diagram
Matching circuit matches receiver load to antenna
Schottky diode generally used as rectifying diode to provide DC power
Low pass filter ensures no RF is input to the power management system
where electrical energy is stored.
Power management circuit enables storage of received power.
Controller ensures delivery of DC power in time when required.
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27. Applications of long range transmission
SOLAR POWER SATELLITES:
The most imp. Application or advancement:
absorb light energy from sun.
converted to electric energy and beamed to earth stations in
form of microwave beams
so it can power satellites,aircrafts,even supply electricity to
places where wired connections are not possible at lower
prices.
SPACE POWER TRANSMISSION AND LUNAR BASED PROJECTS:
satellites in space can receive microwave signals from earth
and beam it to any place on earth.
in future it encourages power projects on the moon
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29. Image of a Rectenna in US with diameter of about half a mile
which is important as 95% of the microwave power is received
by rectennas.US receives about 5000MW of power as a result.
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30. Wireless power transmission and reception
using microwaves
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31. Advantages:
1. Efficient and reliable power.
2. Creation of a shock free environment devoid of any chances
of power thefts.
3. Provides solution to the ever increasing demand for power.
4. A solution to reduce e-waste- a more safe environment.
5. A more cost effective methodology for getting electricity to
your houses which includes paying less for use of power.
6. SPS are not affected by the day and night cycle leads to
lesser limitations on power harvesting.
Disadvantages:
1.For short and mid range transfer system has to be set at the
right frequency or there would be no power transfer.
2.For long range the installation cost is high while EMI is also a
concern. 31

32. Conclusion:
Wireless electricity is not just a great idea but an urgent measure
that has to be taken to deal with the current energy crisis.
Even the smallest entity can lead to one of the most
mindboggling dilemmas of the world. Electrons the source of
electricity puts us in a similar fix. It is on us to decide how to tap
these electrons to be useful in our lives.
Wireless electricity comes with its baggage but no can deny
that it is here to stay.
Prospects & Issues:
From the discussion its clear that this idea needs awareness to
remove doubts from minds of the people about safety issues.
It requires both support from government and the people
financially and psychologically.
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33. References:
•An article published in the Science Magazine as “Wireless Power
Transfer via Strongly coupled magnetic fields ”
•“Efficient Non-Radiative Midrange Energy Transfer” by Aristeidies
karalis, Marlin Soljacic,2006.
• http://ieeexplore.ieee.org/Xplore/
•www.WiTricity.com
•www.WiTricitypower.com
•www.techjournal.com
•www.wikipedia.org
•http://www.sciencedirect.com/science/journals
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