Transcript Presented By Ashutosh Trivedi (0704320011)           WiTricity HOW WIRLESS POWER COULD WORK How Safe is WiTricity? MIT's Experiment: The Future of WiTricity. METHODS USED FOR WIRELESS POWER TRANSMISSION ADVANTAGES OF WITRICITY DISADVANTAGES APPLICATIONS Conclusions.

Presented By
Ashutosh
Trivedi
(0704320011)
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WiTricity
HOW WIRLESS POWER COULD WORK
How Safe is WiTricity?
MIT's Experiment:
The Future of WiTricity.
METHODS USED FOR WIRELESS POWER
TRANSMISSION
ADVANTAGES OF WITRICITY
DISADVANTAGES
APPLICATIONS
Conclusions
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WiTricity is nothing but wireless electricity.
Transmission of electrical energy from one
object to another without the use of wires
is called as WiTricity.
WiTricity will ensure that the cellphones,
laptops, iPods and other power hungry
devices get charged on their own, eliminating
the need of plugging them in. Even better,
because of WiTricity some of the devices
won't require batteries to operate.
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WiTricity - Wireless Electricity, these words are simpler said than
done. The concept behind this fascinating term is a little complex.
However, if you want to understand it, try and picture what I state in
the next few lines. Consider two self resonating copper coils of same
resonating frequency with a diameter 20 inches each. One copper
wire is connected to the power source (WiTricity transmitter), while
the other copper wire is connected to the device (WiTricity Receiver).
The electric power from the power source causes the copper coil
connected to it to start oscillating at a particular (MHz) frequency.
Subsequently, the space around the copper coil gets filled with nonmagnetic
radiations. This generated magnetic field further transfers
the power to the other copper coil connected to the receiver. Since
this coil is also of the same frequency, it starts oscillating at the same
frequency as the first coil. This is known as 'coupled resonance' and
is the principle behind WiTricity
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Human beings or other objects placed between
the transmitter and receiver do not hinder the
transmission of power. However, does
magnetic coupling or resonance coupling have
any harmful effects on humans?
MIT's researchers are quite confident that
WiTricity's 'coupling resonance' is safe for
humans. They say that the magnetic fields tend
to interact very weakly with the biological
tissues of the body, and so are not prone to
cause any damage to any living beings.
MIT's Experiment:
In 2007, Marin Soljacic led a five member team of researchers at MIT
(funded by Army Research Office, National Science Foundation and the
Department of Energy) and experimentally demonstrated transfer of electricity
without the use of wires. These researchers were able to light a 60W bulb
from a source placed seven feet away, with absolutely no physical contact
between the bulb and the power source.
The first copper coil (24 inches in diameter) was connected to the power
source and the second was connected to the bulb, and were made to
resonate at a frequency of 10 MHz. The bulb glowed even when different
objects (like a wooden panel) were placed between the two coils. The system
worked with 40% efficiency and the power that wasn't utilized remained in
the vicinity of the transmitter itself, and did not radiate to the
surrounding environment
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MIT's WiTricity is only 40 to 45% efficient and according to Soljacic,
they have to be twice as efficient to compete with the traditional
chemical batteries. The team's next aim is to get a robotic vacuum or
a laptop working, charging devices placed anywhere in the room and
even robots on factory floors. The researchers are also currently
working on the health issues related to this concept and have said
that in another three to five years time, they will come up with a
WiTricity system for commercial use.
WiTricity, if successful will definitely change the way we live. Imagine
cellphones, laptops, digital camera's getting self charged! Wow! Let's
hope the researchers will be able to come up with the commercial
system soon. Till then, we wait in anticipation!
WiTricity, if successful will definitely change
the way we live. Imagine
cellphones, laptops, digital camera's getting
self charged!
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1. INDUCTION (INDUCTIVE COUPLING)
2.RESONANT INDUCTION (EVANESCENT WAVE
COUPLING
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This is the first method used for wireless power
transfer.The simplest example for wireless
energy transfer using this method is the electrical
transformer. in this electrically isolated from
each other. The transfer of energy takes place by
electromagnetic coupling through mutual
induction. The main draw back of this method is
the short range. For efficient working of a system
which uses this method, the receiver must be in
very close proximity to the. transmitter.
A larger, stronger field can be used for energy
transfer over low distance, but this process is
extremely inefficient. Since magnetic field
spreads in all direction, making a large wastage
of energy.
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In this a curved coils of wire uses as an
inductor. A capacitance plate which can hold
a charge attaches to each end of the coil. As
electricity travels through this coil the coil
begins to resonate. Its resonant frequency is
a product of the inductance of the coil and
the capacitance of the plate. Unlike multiple
layer secondry of non resonant transformer
single layer solenoids with closely spaced
capacitor plates on each end as shown in
figure 1 is used as transmitter and receiver.
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No need of line of sight — In witricity power transmission there is any need
of line of sight between transmitter and receiver. That is power transmission
can be possible if there is any obstructions like wood, metal, or other devices
were placed in between the transmitter and receiver.
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2.No need of power cables and batteries — Witricity replaces the use of
power cables and batteries.
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3.Does not interfere with radio waves
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4. Wastage of power is small - Electromagnetic waves would tunnel, they
would riot propagate through air to be absorbed or dissipated. So the
wastage is small.
5. Negative health implications — By the use of resonant coupling wave
lengths produced are far lower and thus make it harmless.
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6.Highly efficient than electromagnetic induction Electro magnetic induction system can be used for
wireless energy transfer only if the primary and
secondary are in very close proximity. Resonant
inductionsystem is one million times as efficient as
electro magnetic induction system.
7.Less costly - The components of transmitter and
receivers arecheaper. So this system is less costly
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1.Wireless power transmission can be
possible only in few meters.
2.Efficiency is only about 40 %, As witricity is
in development stage, lot of work is done for
improving the efficiency and distance
between transmitter and receiver.
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APPLICATIONS
Witricity has a bright future in providing
wireless electricity. There are no limitations in
witiricity power applications. Some of the
potential applications are pwering of cell
phones, laptops and other devices that
normally run with the help of batteries or
plugging in wires. Witricity applications are
expected to work on the gadgets that are in
close proximity to a source of wireless power,
where in the gadgets charges automatically
without necessarily having to get plugged in
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. By the use of witricity there is no need of
batteries or remembering to recharge
batteries periodically. If a source is placed in
each room to provide power supply to the
whole house, Witricity has many medical
applications. It is used for providing electric
power in many commercially available
medical implantable devices. Another
application of this technology includes
transmission of information. It would not
interfere with radio waves and it is cheap
andefficient.
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Witricity is in development stage, lots of
work is to be done to use it for wireless
power applications. Currently the project is
looking for power transmission in the range
of 100w. Before the establishment of this
technology the detailed study must be done
to check whether it cause any harm on any
living beings
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