WiTricity: Future of Electricity
Mr. Abhinav Bansal
Department of ECE
Roll no.: 1103331064
Department of electronics & Communication
• 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
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
Why not wires??
• As per studies, most electrical energy
transfer is through wires.
• Most of the energy loss is during
• On an average, more than 30%
• In India, it exceeds by 40%
Why not batteries??
Estimated that 40 billion batteries per
year add to the e-waste burden.
And of course its not a good sign.
And this is possible due to
Imagine your cell phones, laptops, i-pods and
other power hungry devices getting charged on
their own, eliminating the need of plugging in.
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.
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
The forgotten invention is reborn in
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, inductiv
Efficiency at that point was
just approximately 43%.
O u r e x p e r i me n t a l s c h e me
c o n s i s t s o f t w o S e l f -
r e s o n a n t c o i l s . O n e c o i l
(s o u r c e c o i l ) i s c o u p l e d
i n d u c t i v e l y t o a n
o s c i l l a t i n g c i r c u i t ; t h e
o t h e r (d e v i c e c o i l ) i s
c o u p l e d i n d u c t i v e l y t o a
r e s i s t i v e l o a d . S e l f -
r e s o n a n t c o i l s r e l y o n t h e
i n t e r p l a y b e t w e e n
d i s t r i b u t e d i n d u c t a n c e a n d
d i s t r i b u t e d c a p a c i t a n c e t o
a c h i e v e r e s o n a n c e .
Power source is connected to ac
Bulb is connected to capture
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.
• Electricity is a general
term that encompasses
a variety of phenomena
resulting from the
presence and flow of
• Magnetism is a force
that acts at a distance
due to a magnetic field.
This field is caused by
charged particles or is
inherent in magnetic
induction is the
voltage across a
through a magnetic
• Electromagnetism is
one of the four
nature, along with
gravitation. It is the
force that causes
• 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
frequencies). At these
small periodic driving
forces can produce
Types of wireless energy transfer
How does Inductive Coupling work??
Inductive coupling works on
the principles of
“When a current
through a wire, it generates
a magnetic field
perpendicular to the wire.
When a wire is in proximity
to a magnetic field, it
generates a current in that
Magnetic fields decay
quickly , making inductive
coupling effective only at
very short ranges.
How does Resonant Induction
• Resonant induction
still uses the same
principles as magnetic
fields to transfer
current) , but it uses
resonance to increase
the range at which the
efficiently take place.
• “Resonance", a
causes an object toWiTricity is based on Resonant
Long range: Far field power transfer
• Far-field method achieves
longer ranges which is much
greater than the diameter of
• These far-field type techniques
include Radio & Microwave
Power Transmission Techniques
& LASER Techniques.
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-
Efficiency Chart of
It is observed that efficiency decreases
with increase in distance between source
Is WiTricity Technology
technology is a non-
radiative mode of
instead on the
magnetic near field.
• Magnetic fields
interact very weakly
and animals—and are
regarded to be safe.
• Automatic wireless charging of mobile electronics in home, cars, offices.
• Mobile phones, Laptops, Game controllers etc.
• Direct wireless power and communication interconnections at points of use in
• In Drilling, Mining, Underwater etc.
• Automatic wireless charging for existing electric vehicle classes.
• In Golf carts, Cars etc.
Other Applications( Medical devices, Military applications
Benefits of WiTricity
It will make products :
• -No manual recharging or changing
• -Eliminate unsightly, unwieldy and costly
• -Never run out of battery power.
• -Reduce product failure rates by fixing
the „Weakest link‟: flexing wiring and
More Environmentally Friendly:
• -Reduce use of disposable batteries.
• -use efficient electric „grid poWer‟
• Safe, fairly efficient, good
• Boon for the devices which uses
• No need of line of sight.
• No need of power cables and
• Magnetic fields interact
• Transmissions possible only in
• possibility of “energy theft”.
• Efficiency decreases with
• The resonance condition should
be satisfied and if any error
exists, there is no possibility of
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
• 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 ”