1) Wireless power transmission through resonance coupling was proposed by Nikola Tesla in 1899 and experiments were conducted at MIT to transmit power without wires over short distances. 2) Witricity uses resonant inductive coupling to efficiently transfer power between two electromagnetic resonators over mid-range distances without power loss. 3) Applications of wireless power include powering consumer electronics, electric vehicles, and industrial/transportation systems without wires, helping reduce e-waste and installation costs.

1. ELECTRICITY THROUGH
WIRELESS
TRANSMISSION-
WITRICITY
by
Apoorva

2. Introduction
 In our present electricity generation system
we waste more than half of its resources.
Especially transmission and distribution
losses are main concern of the present
power technology.
 The transmission and distribution system
causes a loss of 26% to 30% of energy
generated.
 The transmission of power without wires is

3. History of Wireless Power
In 1899, Sir Nikola Tesla Proposed
a method of Wireless Power
Transmission.
Nikola Tesla – The Genius
He enlighted 200 lamps at the
distance of 40 km, Wirelessly !
The efficient midrange power
transfer concept is Witricity. In this
model source and load are in
Magnetic resonance so there is no
power loss.

4. Research at MIT
* Prof. Soljacic – Another
Genius
MIT-IBM Collaboration
* He did succeed to
redesign Tesla’s
experiment in safer way.
* They had lit up a 60W
bulb with a power source
at a distance of 7 feet(over
2m) with no wires

5. The forgotten invention is reborn in 2007
RESONANCE COUPLING
 A group of engineers at MIT came up with the idea to use
resonant induction to transmit power wirelessly.
“Resonance", a phenomenon that causes an object to vibrate when
energy of a certain frequency is applied.

6. Experiment demonstrated at MIT.
A 60W light bulb lit from source at a distance of 2m from
load.

7. Electric bulb lightened even when a barrier was
kept in between.

8. Need of Witricity:
* Cell phones, i pods, laptop computers are
capable of re-charging themselves without
ever being plugged in.

9. What is WiTricity ?
definition is :
* “Transmission of energy through the air”.
* A system of two electromagnetic
resonators coupled mostly through
their magnetic fields.
** Cables are going to replaced by WiTricity.
Efficient power transfer

10. Types and Technologies
 Near-field techniques
 Inductive Coupling
 Resonant Inductive Coupling
 Air Ionization
 Far-field techniques
 MicrowavePower Transmission (MPT)
 LASER power transmission

11. Inductive coupling
 Primary and secondary coils are not
connected with wires.
 Energy transfer is due to Mutual Induction

12. Cont…
 Energy transfer devices are usually air-cored
 Transformer is an example
 Wireless Charging Pad(WCP),electric brushes
are some examples
 The charging pad (primary coil) and the
device(secondary coil) have to be kept very
near to each other

13. Resonance Inductive
Coupling(RIC)
* Same concept as Inductive coupling just
that the coils operate at resonant
frequency leading to efficient transfer of
energy over a larger distance.
* Interacts weakly with extraneous off resonant
objects.
* Radiation loss will be negligible

14. Resonant Inductive Coupling

15. Air Ionization
 Toughest technique under near-field energy
transfer techniques
 Air ionizes only when there is a high field
 Needed field is 2.11MV/m
 Natural example: Lightening
 Not feasible for practical
implementation.

16. Far-field energy transfer
 Microwave Power Transfer(MPT)
 Transfers high power from one place to another.
 Steps:
 Electrical energy to microwave energy
 Capturing microwaves using rectenna
 Microwave energy to electrical energy
 AC can not be directly converted to microwave
energy
 AC is converted to DC first
 DC is converted to microwaves using magnetron
 Transmitted waves are received at rectenna
which rectifies, gives DC as the output
 DC is converted back to AC

17. LASER transmission
 LASER is highly directional, coherent
 Not dispersed for very long
 But, gets attenuated when it propagates
through atmosphere
 Simple receiver
 Photovoltaic cell
 Cost-efficient

18. Applications
 Direct Wireless Power
 No device needs wires
 For TVs, toasters or any form of
Immobile devices
 Automatic Wireless Charging
 Device with rechargeable
batteries
charges itself
 For any form of mobile device

19. Some more Applications…
* Consumer electronics.
*Industrial
 would be free of heavy installation of wires and devoid
of any hazardous electric shock incidents.
*Transportation
 Could charge an electric car or automobile.

20. Wireless power transmission is
safe
 Human beings or other objects placed
between the transmitter and receiver do
not hinder the transmission of power.
 magnetic fields tend to interact very
weakly with the biological tissues of the
body, and so are not prone to cause any
damage to any living beings.

21. Advantages
 Efficient and reliable power.
 Creation of a shock free environment devoid of
any chances of power thefts.
 Provides solution to the ever increasing demand
for power.
 A solution to reduce e-waste- a more safe
environment.
 A more cost effective methodology for getting
electricity to your houses which includes paying
less for use of power.
 Not affected by the day and night cycle, leads to
lesser limitations on power harvesting.

22. Disadvantages.
 For short and mid range transfer system
has to be set at the right frequency or
there would be no power transfer.
 For long range the installation cost is high.

23. CONCLUSION
 Transmission without wires- a reality
 Efficient
 Low maintenance cost. But, high initial
cost
 Better than conventional wired transfer
 Energy crisis can be decreased
 Low loss
 In near future, world will be completely
wireless