Witricity is a technology that allows wireless transmission of electrical energy between two objects without using wires. It works using near-field inductive coupling through magnetic field resonance between two coils that have the same resonant frequency. While earlier wireless power proposals radiated most power inefficiently, witricity can transfer power efficiently over short and mid-range distances. It has advantages over wires and avoids issues with batteries by enabling wireless charging of various electronic devices either built-in or placed near a transmitter. Researchers are working to improve witricity's range and efficiency for applications like powering electronics and charging electric vehicles wirelessly.

1. WITRICITYWITRICITY
Submitted by :Submitted by : Submitted to:Submitted to: . .. .
Krishan kant meena Mrs. Swapnila KhangarotKrishan kant meena Mrs. Swapnila Khangarot
15ESREE20015ESREE200 ((Head of Department of EEHead of Department of EE))
~ WIRELESS ELECTRICITY

2. WHAT IS WITRICITY?
 Transmission of Electrical energy
from one object to other without
use of wires.

3. History of WitricityHistory of Witricity
 In 1899, Sir Nikola Tesla ProposedIn 1899, Sir Nikola Tesla Proposed
a method of Wireless Powera method of Wireless Power
TransmissionTransmission..
 As it is in Radiative mode, mostAs it is in Radiative mode, most
of the Power was wasted and hasof the Power was wasted and has
less efficiency.less efficiency.
 The efficient midrange powerThe efficient midrange power
transfer concept is Witricity.transfer concept is Witricity.

4. Need of Witricity:
 Due to Rapid development of autonomous electronics like
laptops, cell-phones etc. devices typically rely on chemical
energy storage(Battery)
If we adopt this witricity concept to these devices, we may eliminate
the problems caused by the battery. We may use this by fixing on our
room ceiling to charge our devices wirelessly.

5. How does Witricity Work?How does Witricity Work?
Near-field inductive coupling through magnetic
fields.
Interact weakly with surrounding objects.
The basic principle involved in Witricity concept is,
Two objects having same resonating frequency and
in Magnetic resonance at Strongly coupled regime
tend to exchange energy , while dissipating
relatively little energy to the extraneous off-resonant
objects.

6. Methods of wireless energy
transfer
Radiative Methods
 Omni-Directional Radiation
 Uni-Directional Radiation
Non Radiative Methods
 Electromagnetic Induction
 Resonant Coupling

7. Uni-DirectionalUni-Directional
Radiation :Radiation :
► can be efficiently used forcan be efficiently used for
energy transfer even for longenergy transfer even for long
distancesdistances
► but require existence of anbut require existence of an
uninterruptible line-of-sightuninterruptible line-of-sight
► Also not Eco friendly.Also not Eco friendly.
Omni-DirectionalOmni-Directional
Radiation :Radiation :
► Since radiation spreadsSince radiation spreads
in all directions, a vastin all directions, a vast
majority of power wouldmajority of power would
end up being wasted intoend up being wasted into
free space.free space.
► So radioactive modes ofSo radioactive modes of
omni directionalomni directional
antennas are not suitableantennas are not suitable
for the Power transfer.for the Power transfer.

8. ElectromagneticElectromagnetic
InductionInduction
 The action of an electrical transformer is theThe action of an electrical transformer is the
simplest instance of wireless energy transfer.simplest instance of wireless energy transfer.
 The energy is transferred from primary toThe energy is transferred from primary to
secondary coil by induction coupling.secondary coil by induction coupling.
 The main drawback to induction, however, is theThe main drawback to induction, however, is the
short range. The receiver must be in very closeshort range. The receiver must be in very close
proximity to the transmitter or induction unit inproximity to the transmitter or induction unit in
order to inductively couple with it.order to inductively couple with it.

9. Examples of Electromagnetic inductionExamples of Electromagnetic induction
 The electricThe electric
toothbrush batterytoothbrush battery
charger.charger.
 The induction cookerThe induction cooker
stovetop.stovetop.

10. Resonant couplingResonant coupling
 In 2007 researchers at MIT found a way ofIn 2007 researchers at MIT found a way of
increasing the distance between the primaryincreasing the distance between the primary
and secondary coil of a transformer byand secondary coil of a transformer by
introducing the phenomenon of resonanceintroducing the phenomenon of resonance
between the two coils.between the two coils.
 ““Resonance", a phenomenon that causes anResonance", a phenomenon that causes an
object to vibrate when energy of a certainobject to vibrate when energy of a certain
frequency is applied.frequency is applied.

12. How Resonant Coupling actually worksHow Resonant Coupling actually works

13. Frequency of Oscillating circuitFrequency of Oscillating circuit
►The frequency of oscillations can beThe frequency of oscillations can be
approximated asapproximated as
F = 1 / (2π √(LC)F = 1 / (2π √(LC) ))
Where f = frequencyWhere f = frequency
L = inductanceL = inductance
C = capacitanceC = capacitance

14. ► In real-world LC circuits there's alwaysIn real-world LC circuits there's always
some resistance which causes thesome resistance which causes the
amplitude of the current to grow smalleramplitude of the current to grow smaller
with each cycle, however it does not effectwith each cycle, however it does not effect
the frequency of the circuit. After a fewthe frequency of the circuit. After a few
cycles the current diminishes to zero. Thiscycles the current diminishes to zero. This
is called a "damped sinusoidal" waveform.is called a "damped sinusoidal" waveform.

15. • Where there's a natural frequency there's a way
to excite a resonance. We do this by hooking an
alternating current (AC) power supply to the
circuit.

16.  we have put a resistor back in the circuit. If there
is no resistor in the circuit the current's amplitude
will increase until the circuit burns up.
 As a rule of thumb, a circuit will not oscillate
unless the resistance (R) is low enough to meet
the following condition:
R=2 √(LC)

17. Disadvantages of resonant couplingDisadvantages of resonant coupling
 Works only in midrange, around 7 to 10Works only in midrange, around 7 to 10
feet.feet.
 Efficiency is only 40 % .Efficiency is only 40 % .

18. Advantages of Resonant CouplingAdvantages of Resonant Coupling
No need for direct line of sight.No need for direct line of sight.
Elimination of power cables and wires.Elimination of power cables and wires.
Does not interfere with radio waves.Does not interfere with radio waves.
Energy is only transferred between theEnergy is only transferred between the
resonant coils.resonant coils.

19. No chance of getting an electric shock as theNo chance of getting an electric shock as the
energy transfer only takes place between theenergy transfer only takes place between the
resonant objects.resonant objects.
The electrical component of theThe electrical component of the
electromagnetic field of the transmitting coilelectromagnetic field of the transmitting coil
is very small and magnetic fields tend tois very small and magnetic fields tend to
interact very weakly with the biologicalinteract very weakly with the biological
tissues of the body, and so are not prone totissues of the body, and so are not prone to
cause any damage to any living beings.cause any damage to any living beings.
Only one transmitting source can power upOnly one transmitting source can power up
many receiving coils of same resonantmany receiving coils of same resonant
frequency.frequency.

20. Human beings or other objects placedHuman beings or other objects placed
between the transmitter and receiverbetween the transmitter and receiver
do not hinder the transmission ofdo not hinder the transmission of
power.power.

21. Efficiency can be increased with time,Efficiency can be increased with time,
most of the 60% lost is from heatmost of the 60% lost is from heat
radiated from the coils.radiated from the coils.
Still more efficient than traditionalStill more efficient than traditional
wires.wires.

23. Witricity TodayWitricity Today
• MIT powered 60 watt light bulb from 2
meters (7 ft) at 40% efficiency
• MIT researchers working on improving
the technology

24. Witricity TomorrowWitricity Tomorrow
1) Power from mains to antenna, which is made of copper
2) Resonates 10MHz (electromagnetic waves)
3) Tunnel up to 2m (6.5ft)
4) Electricity received by antenna, also resonating at 10MHz.
5) Energy not transferred to laptop re-absorbed by source
antenna. People/other objects not affected as not resonating
at 10MHz

25. ApplicationsApplications
• Wireless power to consumerWireless power to consumer
electronics.electronics.
• Wireless charging for Laptops andWireless charging for Laptops and
Cell phones.Cell phones.

26. • TransportationTransportation ::
Charging pads for electric cars soCharging pads for electric cars so
you don’t have to plug the car inyou don’t have to plug the car in
every time you come into theevery time you come into the
garage.garage.

30. Conclusion:Conclusion:
• Witricity is a promising new technology
which will finally free us from the hassle of
batteries and charging them.
• It will also help us get rid of all the wires
associated with electric appliances.
• According to the latest research, it is now
possible to run an LCD TV without electric
wiring.

32. WORLD IN OUR DREAMWORLD IN OUR DREAM

33. Witricity ConcernsWitricity Concerns
 Will it harm me?Will it harm me?
 Will it harm the environment?Will it harm the environment?
 Will it interfere with importantWill it interfere with important
communication?communication?

34. QuestionsQuestions
?