1. Seminar
on
WiTricity: Future of Electricity
Submitted to:
Mr. Abhinav Bansal
Assistant Professor
Department of ECE
Submitted by:
Hina Saxena
ECE-3rd year
Roll no.: 1103331064
Department of electronics & Communication

2. Contents
• What do you mean by WiTricity?
• Need of 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
• References

3. What is WiTricity
• 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 be replaced by WiTricity

4. Why we need Witricity
• We use Wires..

5. And we use..

6. Which sometimes ends as..

7. Why not wires??
• As per studies, most electrical energy transfer is throughwires.
• Most of the energyloss is during transmission
• On an average, more than30%
• In India, it exceeds by 40%
Why not batteries??
Estimated that 40 billionbatteries per year add to the e-waste burden.
And of courseits not a good sign.

8. And this is possible due to
WIreless elecTRICITY
or WiTricity..
Imagine your cell phones, laptops, i-pods and
other power hungry devices getting charged on
their own, eliminating the need of plugging in.

9. History of Wireless power
 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.
 In 2005, Dave Gerding coined the term WiTricity which is
being used today.

10. 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

11. The forgotten invention is reborn in
2007
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 at a
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%.

12. Experimental design
Our 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.

13. WiTricity Technology
Power source is connected to ac power.
Bulb is connected to capture device.
Blue lines represent the magnetic near field
induced by the power source.
Yellow lines represent the flow of energy from
the source to the capture coil.
This power lights up the bulb.
The magnetic field can wrap around the obstacle
between power source and capture coil.

14. Basics of witricity

15. Fundamentals
• Electricityis a general term that
encompasses a variety of phenomena
resulting from the presence and flow of
electric charge.
• Magnetism is 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.

16. • Electromagneticinduction is the
production of voltage across a
conductor moving through a
magnetic field.
• Electromagnetism is one of the four
fundamental interactions of nature,
along with strong interaction, weak
interaction and gravitation. It is the
force that causes the interaction
between electrically charged particles;
the areas in which this happens are
called electromagnetic fields
• Energy/Power Coupling: Energy
couplingoccurs when an energy
source has a means of transferring
energy to another object.

17. • Resonance : It is the tendency of a
system to oscillate with larger
amplitude at some frequencies than at
others. These are known as the system's
resonant frequencies (or resonance
frequencies). At these frequencies, even
small periodic driving forces can
produce large amplitude oscillations.
• Resonant Magnetic Coupling: Magnetic
coupling occurs when two objects
exchange energy through their varying
or oscillating magnetic fields. Resonant
coupling occurs when the natural
frequencies of the two objects are
approximately the same.

18. Types of wireless energy transfer
techniques
Short range–
Inductive
coupling
Mid range–
Resonance
Inductive
coupling
Long range-
Electromagnetic
Wave Power
Transfer

19. How does Inductive Coupling work??
Inductive coupling works on the principles of
electromagnetism:
“When a current(electricity) passes through a
wire, it generates a magneticfieldperpendicular to
the wire.
Whena wire is in proximity to a magnetic field, it
generates a current in that wire.”
Magneticfields decay quickly , making inductive
coupling effective only at very short ranges.
• Wireless ChargingPad(WCP),electric brushes are
some examples
• On a WCP, the devices are to be kept, batterywill
be automaticallycharged.

20. How does Resonant Induction work??
• Resonant induction still uses the
same principles as magnetic
induction (magnetic fields to
transfer current) , but it uses
resonance to increase the range
at which the transfer can
efficiently take place.
• “Resonance", a phenomenon that
causes an object to vibrate when
energy of a certain frequency is
applied.
WiTricity is based on Resonant Inductive coupling..

21. Long range: Far field power transfer
• Far-fieldmethodachieves longer ranges which is much
greater than the diameter of device.
• These far-field type techniques include Radio &
Microwave Power Transmission Techniques & LASER
Techniques.

22. How WiTricity works
1) Power from mains to antenna, which is made of copper.
2) Antenna resonates at a frequency of 10MHz, emitting
electromagnetic waves.
3) 'Tails' of energy from antenna 'tunnel' up to 2.5m (8.2ft).
4) Electricity picked up by laptop's antenna, which must also be
resonating at 10MHz. Energy used to re-charge device.
5)Energy not transferred to laptop re-absorbed by source
antenna. People/other objects not affected as not resonating at
10MHz.

24. Efficiency Chart of WiTricity
It is observedthat efficiency decreases with increasein distance between
source coil and load coil.

25. Is WiTricity Technology safe?
• WiTricity’s technology is a non-
radiative mode of energy
transfer, relying instead on the
magnetic near field.
• Magnetic fields interact very
weakly with biological
organisms—people and
animals—and are scientifically
regarded to be safe.
• WiTricity products are being
designed to comply with
applicable safety standards and
regulations.

26. WiTricity Applications
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 use in
harsh environments.
• In Drilling, Mining, Underwater etc.
Transportation
• Automatic wireless charging for existing electric vehicle classes.
• In Golf carts, Cars etc.
Other Applications( Medical devices, Military applications
and Robots)

27. Benefits of WiTricity
It will make products :
More Convenient:
• -No manual recharging or changing batteries.
• -Eliminate unsightly, unwieldy and costly power cords.
More Reliable:
• -Never run out of battery power.
• -Reduce product failure rates by fixing the ‘weakest link’: flexing wiring
and mechanical interconnects.
More Environmentally Friendly:
• -Reduce use of disposable batteries.
• -Use efficient electric ‘grid power’ directly instead of inefficient battery
Charging.

28. Advantages
• Safe, fairly efficient, goodrange
• Boon for the devices which uses midrange power
• No needof line of sight.
• No needof power cables and batteries.
• Magnetic fields interact weakly with biological masses
(humans), and energy is only transmitted between
resonating objects.

29. Limitations
• Transmissions possible only in few meters.
• Possibility of “energy theft”.
• Efficiency decreases withdistance.
• The resonance condition should be satisfied and if any
error exists, there is no possibility of power transfer.

30. Future of Witricity
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!!!”

31. References
• www.wikipedia.com
• S. Sheik Mohammed, K. Ramasamy, T. Shanmuganantham,”
Wireless power transmission – a next generation power
transmission system”, International Journal of Computer
Applications (0975 – 8887)
• An article published in the Science Magazine as “Wireless
Power Transfer via Strongly coupled magnetic fields ”
• www.witricity.com
• http://www.sciencedirect.com/science/journals