1. WiTricityWiTricity

2. Wireless Power TransmissionWireless Power Transmission
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3. What is WPT?What is WPT?
The transmission of energy from one
place to another without using wires
Conventional energy transfer is using
wires
But, the wireless transmission is made
possible by using various technologies
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4. HistoryHistory
Nikola Tesla in late 1890s
Pioneer of induction techniques
His vision for “World Wireless System”
The 187 feet tall tower to broadcast energy
All people can have access to free energy
Due to shortage of funds, tower did not
operate
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5. ORIGINAL WORK OF TESLAORIGINAL WORK OF TESLA
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6.  There’s something new coming up to play
with ‘Wireless Electricity’.
 In the first successful trial of its kind, the
team was able to illuminate a 60-watt
light
bulb 7ft away .
 The team from Massachusetts Institute
of Technology, who call their invention
‘WiTricity‘.

7. What Is Inductive Coupling?
InductiveCoupling is a method for short range
wireless energy transfer.
 Its range can vary, but it’s often very short.
Short Range Wireless EnergyShort Range Wireless Energy
Transmission: Inductive CouplingTransmission: Inductive Coupling

8. Inductive couplingInductive coupling
Primary and secondary coils are not
connected with wires.
Energy transfer is due to Mutual
Induction
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9. How does Inductive CouplingHow does Inductive Coupling
Work?Work?
 Inductive coupling works on the
principles of electromagnetism:
When a current (electricity) passes
through a wire, it generates a magnetic
field perpendicular to the wire.
When a wire is in proximity to a
magnetic field, it generates a current in
that wire.
Magnetic fields decay quickly , making
inductive coupling effective only at very
short ranges.

10.  What Is Resonant Induction?
 A group of engineers at MIT came up with the
idea to use resonant induction to transmit
power wirelessly. They deemed their result
“WiTricity” (like Wi-Fi) . WiTricity can
transmit electricity wirelessly at 40% efficiency
to about 7 feet.
Medium Range Wireless EnergyMedium Range Wireless Energy
Transmission: Resonant InductionTransmission: Resonant Induction

11. Resonance Inductive Coupling(RIC)Resonance Inductive Coupling(RIC)
Combination of inductive coupling and
resonance
Resonance makes two objects interact
very strongly
Inductance induces current
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12. How resonance in RIC?How resonance in RIC?
Coil provides the inductance
Capacitor is connected parallel to the
coil
Energy will be shifting back and forth
between magnetic field surrounding the
coil and electric field around the
capacitor
Radiation loss will be negligible
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13. Block diagram of RICBlock diagram of RIC
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14. An exampleAn example
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16. WiTricity (contd…)WiTricity (contd…)
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17. DisadvantagesDisadvantages
Distance constraint
Field strengths have to be under safety
levels
Initial cost is high
In RIC, tuning is difficult
High frequency signals must be the supply
Air ionization technique is not feasible
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18. Microwave PowerMicrowave Power
Transfer(MPT)Transfer(MPT)
Transfers high power from one place to
another. Two places being in line of sight
usually
Steps:
◦ Electrical energy to microwave energy
◦ Capturing microwaves using rectenna
◦ Microwave energy to electrical energy
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19. MP T (contd…)MP T (contd…)
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
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20. Solar Power Satellites (SPS)Solar Power Satellites (SPS)
To provide energy to earth’s
increasing energy need
To efficiently make use of renewable
energy i.e., solar energy
SPS are placed in geostationary orbits
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21. SPS (contd…)SPS (contd…)
Solar energy is captured using photocells
Each SPS may have 400 million photocells
Transmitted to earth in the form of
microwaves/LASER
Using rectenna/photovoltaic cell, the
energy is converted to electrical energy
Efficiency exceeds 95% if microwave is
used.
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22. RectennaRectenna
Stands for rectifying antenna
Consists of mesh of dipoles and diodes
Converts microwave to its DC
equivalent
Usually multi-element phased array
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23. Rectenna in USRectenna in US
Rectenna in US receives 5000MW of
power from SPS
It is about one and a half mile long
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24. Other projectsOther projects
Alaska’21
Grand Bassin
Hawaii
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25. MIT's WiTricity is only 40 to 45% efficient and they
have to be twice as efficient to compete with the
traditional chemical batteries.
 Aim is to get a robotic vacuum or a laptop working,
charging devices placed anywhere in the room
 The researchers have said that in another five
years time, they will come up with a WiTricity
system for commercial use.
What's the Future of WiTricity?What's the Future of WiTricity?

26. ConclusionConclusion
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
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