WiTricity technology is a non-radiative mode of energy transfer, relying on the magnetic near field. Magnetic fields interact very weakly with biological organisms—people and animals—and are scientifically regarded to be safe.

1. Wireless Power Transfer Via Resonant Inductive Coupling
WITRICITY
Yusra Kaleem
(2013-T.E.-058)
Department of Telecommunication Engineering
Sir Syed University Of Engineering & Technology, Karachi.

2. IntroductiontoWiTricity?
 Nikola Tesla had visions of wireless power about 100 years ago. He set up a
tesla coil in the beginning of 1900 and the idea was supposed to be able to
transfer power anywhere on earth.
 We can’t live without Electricity. There are trillions of dollars that have been
invested in the infrastructure around the world putting up wires.
 We use 40 billion disposable batteries per year for very less amount of power.
But the batteries have limited life.
 Wireless electricity or wireless power transmission is one of the emerging
technologies today.
 The idea of this technology is transmitting power from a source to any receiver
using the free space, same as the TV and radio transmission or same as your
wireless LAN or WIFI.

3.  Some of the uses as of the moment are for charging iPod, cell-phones, digital
cameras, mp3, iPhone and other electronic devices.
 Transfer of electricity without using connections between input and load is
termed as wireless electricity.
 This is not like wireless transmission of signals which we used in the cell
phones.
 In cell phones signals are sent in the form of micro waves whereas in this
mode of transition electricity is transferred in the form of magnetic rays.
Witricity technology is more than …
 Traditional magnetic induction
 Radiative power transfer
 Tesla’s vision of a wireless world.

4. Historyof WiTricity
 Originally demonstrated in 1964 on CBS using model helicopter.
 1969-1975 30 kW over 1 mile at 84% efficiency.
 Wireless power transmission dates back to the19th century when Nikola Tesla
used conduction-based systems to transfer wireless Power.
 The first experiment of WiTricity was conducted in the year 2006 by a five-
member team of researchers from Massachusetts Institute of Technology (MIT).
 MIT powered 60 watt light bulb from 2 meters (7 ft.) at 40% efficiency.

5. HowDoesWiTricityWorks?
 Near-field inductive coupling through magnetic fields.
 Interact weakly with surrounding objects (biological tissue).
 Basic Working Principle:
1. Source coil powered by a main supply usually your power outlet
2. Yellow line is the energy flow from the source that is receiving coil
3. Conducting material that blocks some transmitted energies (blue line)
4. The receiving coil that is connected to the device like your cell-phones, iPods,
mp3, and others.

6. WorkingPrinciple
 Witricity works on the principle of mutual induction between the two coils.
 There are two copper coils arranged one at the sender end and other at the receiver
end.The first coil is attached to the power source while the second coil to the light bulb.
 When the power is switched on the first coil converts the electricity into magnetic field,
which is oscillating at a particular frequency i.e. AC source.
 The second coil at the receiver end converts the magnetic field into electricity .The
surrounding environment is unaffected.

7. Projecting magnetic field
Magnetic vector notation
dB=udH
Induced EMF due to change in flux

9. Key Terms
Electricity: The flow of electrons (current) through a conductor (like a wire), or charges
through the atmosphere (like lightning).
Magnetism: Oscillating magnetic fields vary with time, and can be generated by
alternating current (AC) flowing on a wire. The strength, direction, and extent of magnetic
fields are often represented and visualized by drawings of the magnetic field lines.
Electromagnetism: A term for the interdependence of time-varying electric and
magnetic fields. For example, it turns out that an oscillating magnetic field produces an
electric field and an oscillating electric field produces a magnetic field.

10. Magnetic Induction: A loop or coil of conductive material like copper, carrying an
alternating current (AC), is a very efficient structure for generating or capturing a
magnetic field. If a conductive loop is connected to an AC power source, it will
generate an oscillating magnetic field in the vicinity of the loop. A second
conducting loop, brought close enough to the first, may “capture” some portion of
that oscillating magnetic field, which in turn, generates or induces an electric
current in the second coil. The current generated in the second coil may be used to
power devices. This type of electrical power transfer from one loop or coil to
another is well known and referred to as magnetic induction.
Energy/Power Coupling: Energy coupling occurs when an energy source has a
means of transferring energy to another object.
Key Terms

11. Key Terms
Resonance: It can be thought of as the natural frequency
at which energy can most efficiently be added to an
oscillating system. Example of resonance is the way in
which a singer can shatter a wine glass by singing a single
loud, clear note.
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.

12. Features And Benefits
Witricity’s technology Technology benefits
1. Highly resonant strong coupling High efficiency over distance
1. Energy transfer via magnetic
field
Can penetrate and wrap around obstacles
1. Non radiative energy transfer Safe for living beings and other environmental
objects
1. Scalable design From miliwatts to kilowatts
1. Flexible geometry Device that can fit into OEM (Original Equipment
Manufacturer)

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

14. WitricityTomorrow

15. Advantages
 An advantage is that we can produce electricity anywhere without wires.
 The power can be delivered in any direction i.e. omnidirectional.
 Most common things in our surroundings do not interact with these
magnetic fields and thus not harmful to other living beings.
 Significant de-cluttering of office space.
 No need for meter rooms and electrical closets.
 Reduction of e-waste by eliminating the need for power cords.
 Need more light in your office, no need for electrician. Simply place the
lamp where ever you need it.
 No need of line of sight.
 Does not interfere with radio waves.
 Less costly.

16. System Description
 Across an application space that spans power levels from less than a watt to multiple
kilowatts, a wireless energy transfer system based on HR-WPT often has a common
set of functional blocks.

17. System Description

18. Resonant Repeaters For Long Range Power Transfer

19. Applications
Can be really helpful in charging and implanting
medical devices inside human body including
LVAD, heart assist pumps, pace marks, infusion
pumps, and for surgical replacement of primary
batteries.
LED lights are directly powered by highly
resonant wireless energy transfer system.
For charging full electric and hybrid
electrical vehicles.
Can be used for several military applications
and defense systems.

20. Applications

21. SWOT Analysis
SUCCESS:
1. Transferring electricity wirelessly using free
space.
2. It is completely a safe technology. 100
time safer than making a phone call.
3. Non-radiative mode energy transfer (no
radiations – no radio waves – no harm).
4. Magnetic field interacts very weakly with
biological organisms (humans, animals &
environmental objects).
5. Wastage of power is small.
6. Transmission distance is in mid ranges
from a centimeter to several meters.
WEAKNESS:
1. To achieve better wireless power
transmission the resonance condition
should be satisfied i.e. the power source
must be of same frequency of receiving coil.
2. Possibility of “energy theft”. Someone can
be using your internet or your power.

22. SWOT Analysis
OPPORTUNITY:
1. Endless applications:
 Home electronics.
 Industrial.
 Transportation (Electric vehicles).
 Automatic charging of high tech military
systems (Defense systems).
 Medical devices.
 Wireless charging of smart cards.
2. Range of wireless power transmission can be
increased by using repeaters.
1. No need of line of sight.
2. Does not interfere with radio waves.
3. Less costly.
4. Power can be transmitted through any non-
metallic material including solids, liquid and
gasses.
5. Ability to power devices from single source
resonator.
THREAT / LIMITATION:
1. Strong ferromagnetic material cause low
power transfer, but the magnetic field has
the ability to “wrap around” many metallic
obstacles that might block the magnetic field
and can still transfer power.

23. Practical Model Description

24. WiTricityConcerns
Q: Is WiTricity technology safe?
Q: How much power can be transferred?
Q: Over what distance can WiTricity technology transfer power?
Q: How efficient is WiTricity technology?
Q: Does the efficiency depend on the coil shape or material?
Q: Can WiTricity technology transfer power through walls or obstructions?
Q: How well does WiTricity technology work in the presence of metal walls?
Q: How does WiTricity's technology differ from traditional magnetic induction?
Q: How does WiTricity technology differ from radiative power transfer?
Q: How does WiTricity technology differ from Magnetic Resonance Imaging (MRI)?
Q: How does WiTricity technology differ from Tesla’s Vision of a Wireless World?
Q: Are there other applications apart from just charging up portable devices?
Q. Can power be transmitted through materials other than air? What are the limitations?

25. AnyQuestions???