A SEMINAR REPORT ON
B. Tech 3rd. YEAR (ECE)
Roll no. 1104231050
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
MADAN MOHAN MALAVIYA
UNIVERSITY OF TECHNOLOGY, GORAKHPUR, UTTAR PRADESH
WHY WE NEED?
BASIC OF WIRELESS ELECTRICITY
Normally, we picture electric devices
with wires. For example, laptop, cell
phone, lamp etc.
Remember every time you travel or
at home, you need to pack all the
adapters and chargers for your
devices. It’s unpractical, isn’t it.
The solution is near.
He did enlighten many lamps at the distance of
Later the team from Massachusetts Institute of
Technology (MIT) led by Prof. Marin Soljacic
extend his work and they named their
invention “WiTricity”(Wireless Electricity).
In the first trial, the team was able to
illuminate a 60-watt light bulb 7ft away.
WiTricity team from MIT
Why we need?
Now-a-days due to rapid increase of electronic goods
like cell phones ,laptops ,i-pods etc., which rely on the
chemical storage of energy by the battery & need to
recharge frequently twice a day.
Leads to lot of E-waste.
Precautions to be taken for electrician while working
otherwise he can get shock.
Transmission of energy through the air.
Process of transferring electric energy or power
over distance without wires.
Works on the principle of electromagnetic
Is a form of wireless energy transfer by
resonance, the ability to provide electrical energy
to remote objects without wires using oscillating
Also known as “WiTricity” and “Wireless Power
Power source (transmitter) provides power to the
devices where as capture device (receiver)
Working of Wireless electricity
Charging of a Laptop
DEMONSTRATION OF WIRELESS ELECTRICITY IN DAY-TO –DAY LIFE
Two theories:1)NEAR FIELD THEORY
Valid only for few range (in meter).
Uses Resonant inductive coupling
two coils that are tuned to resonate at the same
Where distance is few times the diameter of the
device & source.
Near field theory
2)FAR FIELD THEORY
Valid for large ranges (in km).
Uses radio wave and laser’s between source &
Where distance is much greater the diameter of
the device & source.
MICROWAVE POWER TRANSMISSION.
Fear field theory
Highly Resonant Strong Coupling Provides High Efficiency over
Energy Transfer via Magnetic Near Field can Penetrate and Wrap
Non-Radiated Energy Transfer, hence is Safe for People and
Scalable Design enables solutions from milliwatts to Kilowatts.
Flexible Geometry allows WPT Devices to be embedded into
No need of line of sight.
No need of power cables.
Wastage of power is small.
Reduction of e-waste by eliminating the need for
Does not interfere with radio waves.
Negative health implications.
Able to penetrate anything.
o Wireless power transmission can be possible only in few
o Efficiency is only about 40%.
o Need for standardization and adaptation. So a little
overheating occurs because of different voltages.
o Refitting old equipment or purchasing new equipment
could become a very expensive endeavor.
o Possibility of “energy theft”.
WPT makes products:
• No manual recharging or changing batteries.
• Eliminate unsightly, unwieldy and costly power cords.
• Never run out of battery power.
• Reduce product failure rates by fixing the ‘weakest link’.
More Environmentally Friendly:
• Reduce use of lots & loops of wires.
• Reduce E-Waste.
Think that the city will be covered
with WPT hot spots , just like
Wireless Internet, there will be no
need of charging batteries, or
carrying adapters all around !
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,
“WE CAN SAVE THE WORLD FROM WIRES”
o Nicola Tesla, ―”The transmission of electrical energy without wires”, Electrical World
and Engineer, March 1905. Page 2-5 .
o William C. Brown, ―”The history of power transmission by radio waves, Microwave
Theory and Techniques”, IEEE Transactions, 32(9 ), September 1984.
o A.B. Kurs, A. Karalis, R. Moffatt, J.D. Joannopoulos, P.H. Fisher, and M. Soljacic,
―”Wireless Power Transfer via Strongly Coupled Magnetic Resonances” Science, 317,
pp. 83-86 (2007)
o A. Karalis, J.D. Joannopoulos, and M. Soljacic, -”Efficient Wireless Non-radiative
Midrange Energy Transfer”, Ann. Phys., 323, pp. 34-48, (2008) published online April
o Hirai, J., Kim, T.-W. and Kawamura, A. -”Wireless transmission of power and
information and information for cableless linear motor drive” IEEE Trans. on power
electronics pp.15, 21 (2000).
o IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency
Electromagnetic Fields, 3 kHz to 300 GHz, IEEE Std. C95.1-2005