1. Mr. AJIT A. JADHAV
WiTricity : A WORLD
WITHOUT WIRES

2. Content
• What is 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

3. What isWiTricity
• 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 WiTricty.

4. Why not wires ??
• As per studies, most electrical energy transfer is
through wires.
• Most of the energy loss is during transmission.
• On an average, more than 30%.
• In India, it exceeds by 40%.
Why not batteries ??
• Estimated that 40 million batteries per year add
to the e-waste burden.
• And of course its not a good sign.

5. History of Wireless power
• In late 1890 : 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 about
15% only.
• In 2005 : DaveGerding coined the
term WiTricity which is being used
today.
• In 2009 : Sony shows a wireless
electrodynamics-induction powered

6. Experimental design
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.

7. basics
magnetism
Magnetic
induction
Electro
magnetism
Resonant
magnetic
coupling
RESONANC
E
electricity
Energy
coupling
Basics of WiTricity

8. Electromagnetic induction 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
coupling occurs when an energy
source has a means of transferring

9. Resonance : 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

10. WiTricity Technology
 Power source is connected to ac
power.
 Bulb is connected to capture device.
 Bluelinesrepresentthemagnetic near
field induced bythe power source.
 Yellow lines represent the
flow ofenergy from the source to the
capturecoil.
 Thispower lightsupthe bulb.
 The magneticfieldcanwrap around the
obstacle between powersource and
capture coil.

11. Types and Technologies of WPT
 Near-field techniques (Short Range)
1. Inductive Coupling
2. Resonant Inductive Coupling
3. Air Ionization
 Far-field techniques (Long Range)
4. Microwave Power Transmission (MPT)
5. LASER power transmission

12. 1. INDUCTIVE COUPLING : Primary and secondary
coils are not connected with wires. Energy transfer is
due to Mutual Induction.
A. Near-field techniques
2. RESONANCE INDUCTIVE COUPLING(RIC) :
Combination of inductive coupling and resonance.
Resonance makes two objects interact very strongly and
inductance induces current.

13. 2. RESONANCE INDUCTIVE COUPLING(RIC) :
3. Atmospheric conduction method : In this method a
closed circuit is made using transmitter, ionized path between
upper atmosphere and transmitter, second ionized path
connecting receiver.
The circuit back to the transmitter is completed through the
earth.

14. ADVANTAGES DISADVANTAGES
 No wires
 No e-waste
 Need for battery is
eliminated
 Efficient energy
transfer using RIC
 Harmless, if field
strengths under
safety levels
 Maintenance cost is
less
 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
Advantages & Disadvantages Of Near-field Techniqu

15. B. Far-field techniques
1. MICROWAVE POWER TRANSFER (MPT) : Power
transmission via radio waves can be made more
directional, allowing longer distance power beaming, with
shorter wavelengths of electromagnetic radiation, typically
in the microwave range.
A rectenna may be used to convert the microwave energy
back into electricity which has an efficiency of 95%.
Transmitted waves are received at rectenna which rectifies,
gives DC as the output. Power beaming using microwaves
has been proposed for the transmission of energy from
orbiting solar power satellites to Earth.

16. 2. 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.
B. Far-field techniques….

17. ADVANTAGES DISADVANTAGES
 Efficient
 Easy
 Need for grids, substations
etc are eliminated.
 Low maintenance cost.
 More effective when the
transmitting and receiving
points are along a line-of-sight.
 Can reach the places which
are remote.
 Radiative
 Needs line-of-sight
 Initial cost is high
 When LASERs are used,
• conversion is inefficient
• Absorption loss is high
When microwaves are used,
interference may arise.
Advantages & Disadvantages Of Far-field Technique

18. 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.
Principle :

19. How wireless power works
 Magnetic coil is housed in a box and can be set in wall
or ceiling.
 Antenna A is powered by mains which resonates at a
particular frequency.
 Electromagnetic waves are transmitted through the air
 Second magnetic coil, antenna B fitted in laptop or TV
resonates with the same frequency as first coil and
absorbs energy.
 Energy charges the device.

20. Is WiTricity safe ?
 WiTricity, however turns electricity into a magnetic
field, which is a non-radiative transfer method.
Magnetism interacts very minimally with biological
organisms and is not harmful at all to humans or
animals.
 WiTricity has been scientifically proven not to be
harmful and has been designed to comply with
applicable safety standards and regulations.

21. Applications of WiTricity
21
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 usein
harshenvironments.
• In Drilling, Mining, Underwateretc.
Transportation
• Automatic wireless charging for existing electric vehicleclasses.
• In Golf carts, Carsetc.
Other Applications( Medical devices, Military applications
and Robots)

22. Benefits andAdvantages
A. Benefits :
It will make products :
- More Convenient
- No manual recharging or changing batteries.
- Eliminate unsightly, unwieldy and costly power cords.
22
- More Reliable:
- Never run out of battery power.
More Environmentally Friendly:
- Reduce use of disposable batteries.
- Use efficient electric ‘grid power’ directly.

23. B. Advantages :
Benefits and Advantages….
• Safe, fairly efficient, good range.
• Boon for the devices which uses midrange
power.
• No need of line ofsight.
• No need of power cables and batteries.
• E-waste is eliminated.
• More secure, no risk of getting shocked.
• Maintenance cost will be saved.

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

25. Just imagine our future