1. Wireless Power
Transmission (WPT)
S.Nandha Kumar,
S.Farith Ashik Rahuman
Final Year-EEE,
Syed Ammal Engineering College,
Ramanathapuram..
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2. What is WPT ?
The transmission of energy from one place
to another without using wires
Conventional energy transfer is using Wires
But the wireless transmission is made
possible by using various technologies
This phenomena is also known as WITRICITY
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3. History of WPT
Nikola Testla in late 1890’s gave the
concept of Witricity
He was able to transfer energy from one
coil to another coil
He managed to light 200 lamps from a
distance of 40km
The idea of tesla is taken into research
after 100 years by team led by Marin
Soljacic from MIT. 10/8/2016WIRELESS POWER TRANSMISSION 3

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 40%
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5. Why WPT?
Reliable
Efficient
Fast
Low Maintenance Cost
Can be used for Short range as well as
long range.
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6. Energy Coupling
The transfer of energy,
Magnetic Coupling
Inductive Coupling
Simplest Wireless Energy Coupling is
a transformer.
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7. Types and Technologies of WPT
Near-Field Techniques:
Electromagnetic Radiation
Inductive Coupling
Magnetic Resonant Coupling.
Far-field Techniques:
Microwave Power Transmission(MPT)
LASER power Transmission. 10/8/2016WIRELESS POWER TRANSMISSION 7

8. Near Field Techniques
Electromagnetic(EM) Radiation:
 Energy from the transmission antenna of a
power source to the receiver antenna
through radioactive EM waves is the process
of emission by EM Radiation.
 Two section classified in the sense of the
direction of emitting energy,
Omni Directional radiation,
Unidirectional radiation.
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9. Inductive Coupling
It is generally coupling between to LC
circuits where resonant frequency is
same.
It works by magnetic field induction
Primary and Secondary coils are not
connected with wires.
Energy transfer is due to Mutual Induction.
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10. Inductive Coupling (contd..)
Transformer is also an example
Energy transfer devices are usually air-
cored
Wireless charging pad(WCP),electric
brushes are some examples
On a WCP,the devices are to be
kept,battery will be automatically charged
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11. Inductive Coupling(contd..)
Electric brush also charges using inductive
coupling
The charging pad (primary coil) and the
device (secondary coil) have to be kept
very near to each other
It is preferred because it is comfortable
Less use of wires
Shock proof. 10/8/2016WIRELESS POWER TRANSMISSION 11

12. Resonance Inductive Coupling(RIC)
Combination of inductive coupling and
resonance
Resonance makes two objects interact
very strongly
Inductance induces current.
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13. How resonance in RIC?
Coil provides the inductance
Capacitor is connected parallel to the
coil
Energy will be shifting back and forth
between magnetic field surrounding
the coil and electric field around the
capacitor
Radiation loss will be negligible.10/8/2016WIRELESS POWER TRANSMISSION 13

14. Witricity
Based on RIC
Led by MIT’s marin soljacic
Energy transfer wirelessly for a
distance just more than 2m
Coils were in helical shape
No capacitor was used
Efficiency achieved was around 40%
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15. Witricity… Some statistics
 Used frequencies are 1Mhz and 10Mhz
 At 1Mhz,field strengths were safe for human
 At 10Mhz,field strength were more than ICNIRP
standards
Witricity Now
 No more helical coils
 Companies like intel are also working on devices that
make use of RIC
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16. Far-Field Techniques
 The far-field techniques are measuring
the electrical load far from the power
source.
 These techniques aim at high power
transfer and need line of sight.
 It can be separated into two categories,
which are,
 Microwave power transmission and
 Laser power transmission.
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17. Microwave Vs LASER Transmission
Microwave
 Transmission via radio waves
 More developed
 High efficiency upto 85%
 Cause Interference with
satellite communication
industry
 Losses occur due to
atmospheric absorption and
scattering by clouds,fog,rain
etc is less
LASER
 Transmission via laser beam
 Recently developed
 Allows the efficient transmission of
power (40%-50%)
 Confirms to limit an eye and skin
damage
 Atmospheric absorption and scattering
by clouds,fog,rain etc causes upto
100% losses.
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18. Recent Technologies
Qi Technology:
 This technology uses the small inductors to transmit
power over higher frequencies and also support a charging
distance of a few cm.
A4WP Technology:
 Its enabling the efficient transfer of power to electronic
devices.
 This is based on reference power transmitting and
receiving resonators without the use of interconnecting
wires.
 Advantage of A4WP is allowing charger to be embedded in
the objects where the magnetic fields can still emit the
energy from the objects.
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19. Power Matters Alliance(PMA) Technology
 This is the organization with the aim of forward
thinking in a global,not for profit, industry where
better power supply for battery equipped devices
using wireless charging technology has been
working with a bunch of research group leaders.
 PMA growth and success is attributed to a unique
approach of making wireless charging ubiquitous
in the places that consumers need it most as well
as the hard work and dedication for members.
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20. 10/8/2016WIRELESS POWER TRANSMISSION 20

21. Applications of WPT
Field of electronics
Electronics is the largest application field of using WCS is being implemented
in electronic products such as Laptop,Ipad,Smartphones..etc
Medical devices
WPT has been widely used for implanted medical devices includes LVAD
heart assist pumps,pacemakers and infusion pumps
Electrical vehicles
Rechargeable hybrid and battery electric vehicles can be directly powered
with WCS.These system deliver 3.3kw at high efficiency over a distance of
20Cm.
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22. LED lighting
With using WPT in LED lights,we can directly charge our devices. So it
can eliminate the need for batteries in under cabinet task lighting.
Defense systems
Use of defense system is helmet mounted electronics where night vision is included
and radio devices that can be powered wirelessly from a battery pack carried in
the solidiers vest ,eliminating the need for disposable batteries or a power cord
connecting the helmet to the vest mounted battery pack.
Solar power Satellites(SPS)
It is the large application of WPT by using satellites with giant solar arrays
and placing them in GEO.These satellites plays a pivotal role to generate
and transmit the power as microwaves to the earth.
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23. Conclusion
 There recent technological applications that make the human
life more beneficial in the present world.
 The huge magnetic field and large charging distance must be keep
ahead this technology then other standards whereas Qi and
PMA also improving very fast.
 More applications that are in under research with wireless
power charging and in the field of robotics will be in our daily
uses only if wireless power keeps improving.
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24. THANK YOU
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