By T.SELVALAKSHMI, FINAL YEAR ECE DR.G.U.POPE COLLEGE OF ENGINEERING, SAWYARPURAM

1. WIRELESS POWER
TRANSMISION
BY
T.SELVALAKSHMI,
FINAL YEAR ECE
DR.G.U.POPE COLLEGE OF ENGINEERING,
SAWYARPURAM

2. OVERVIEW
 Abstract
 Introduction to wireless power transmission(WPT)
 Need of WPT
 History of WPT
 Varieties of WPT
 Advantages And Disadvantages
 Applications
 Future Scope
 Conclusion
 Reference

3. ABSTRACT
• Wireless power transmission (WPT) has been attracting a wide range of subjects in
various fields and also become a highly active research area because of their
potential in providing high technology to our daily lives. The wireless power
transmission will be mandatory to use in the near future because this technology
enables the transmission of electrical energy from a power source to an electrical
load across an air gap without interconnecting wires. In this paper, we carry out a
pilot study to present the existing technologies of wireless power transmission, their
recent technology as well as its future trends. Furthermore, we also describe plenty
of applications in wireless transmission.

4. INTRODUCTION TO WPT
• Efficient transmission of electric power from one
point to another through vacuum or an atmosphere
without the use of wire or any other substance.
• WPT can transport power to locations which are
otherwise not possible or impractical to reach.

5. WHY NOT WIRES? NEED OF WPT
• 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%
• Reliable
• Environmentally sound
• Efficient
• Low Maintenance Cast
• Can be used for short-range or
long-range

6. HISTORY OF WPT
• In 1897 Nikola Tesla pioneer of induction
techniques,had a vision for “World Wireless
System”.
• A 187 feet tall tower was build to broadcast
energy
• So that all people can have access to free
power.
• He managed to 200 light lamps from a
distance of 40km.
• Figure:Telsa’s colorado springs lab

7. GENERAL BLOCK DIAGRAM OF WPT SYSTEM

8. VARIETIES OF WPT
WPT
Near-field
technique
s
Inductive
coupling
Resonant
Inductive
coupling
Far-field
technique
s
Microwave
power
transmissi
on
LASER
power
transmissi
on

9. INDUCTIVE COUPLING
• Primary and secondary coils are not connected with
wires
• Energy transfer is due to Mutual inductance
• Example:Transformer,Wireless Charging
Pad(WCP),Electric brushes
• On a WCP,the devices are to be kept,battery will be
automatically charged
• 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.

10. RESONANT INDUCTIVE COUPLING(RIC)
• Combination of inductive
coupling and resonance.
• Resonance makes two objects
interacts very strongly.
• Inductance induces current.

11. RIC VS. INDUCTIVE COUPLING
• RIC is highly efficient.
• RIC has much greater range than inductive coupling.
• RIC can be one-to-many,But usually inductive coupling is one-to-one.
• Devices using RIC technique are highly portable.

12. ADVANTAGES &DISADVANTAGES OF NEAR-
FIELD TECHNIQUES
• ADVANTAGES
 No wires
 No e-waste
 Need for battery is eliminated
 Efficient energy transfer using RIC
 Harmless, if field strengths under safety level
 Maintenance cost is less
• Disadvantages
 Distance constraint
 Field strengths have to be under safety level
 Initial cost is high

13. FAR-FIELD ENERGY TRANSMISSION
• It aims at high power transfer.
• It can be LASER or Microwave transmission.
• It needs line-of-sight.
• It is radiative in nature.
• AC cannot be directly converted to microwave energy.
• AC is converted to DC first.
• DC is converted to microwaves using magnetron.
• Transmitted waves are received at rectenna which rectifies, gives DC as the output.
• DC is converted back to AC.

14. LASER TRANSMISSION
• LASER is highly directional, coherent.
• Not dispersed for very long.
• But, gets attenuated when its propagates through atmosphere.
• Simple receiver
• Photovoltaic cell
• Cost-efficient.

15. SOLAR POWER SATELLITES( SPS )
• To efficiently make use of
renewable energy i.e.,solar energy.
• SPS are placed in geostationary
orbits.
• Solar energy is captured using
photocells.

16. RECTENNA
• Rectenna Stands for rectifying antenna
• Consists of mash of dipoles and
diodes.
• Converts microwave to its DC
equivalent
• Rectenna in US
• It receives about 5000MW of power
from SPS.
• It is about one and a half mile long.

17. PROJECTS BASED ON WPT
ALASKA’ 21 GRAND BASSIN
HAWII
DEMONSTRATION

18. ADVANTAGES OF FAR-FIELD TECHNIQUES
• 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

19. DISADVANTAGES OF FAR-FIELD
TECHNIQUES
• 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
• Fried Bird effect

20. APPLICATIONS
• Near-field energy transfer
• Electric automobile charging
• Static and moving
• Consumer electronics
• Industrial purposes
• Far-field energy transfer
• Solar power satellites
• Energy to remote areas
• Can broadcast energy globally(in future)

21. FUTURE SCOPE
• In future transmission will be without wires.
• It would be more efficient.
• Low maintenance cost, but high initial cost.
• Better than conventional wired transfer.
• Energy crisis can be decreased.
• Low power loss.
• In near future, world will be completely wireless.

22. REFERENCE
• http://www.Leonardo-energy.com/sites/Leonardo-
energy/files/root/pdf/2009/wirelesspower.pdf
• http://www.witricity.com/assets/highly-resonant-power-transfer-keslerwitricity-
2013.pdf
• “A Few Things you occasionally wanted to know about wireless power
transmission.” Potter, Seth.
http://www.spacefuture.com/archive/a_few_things_you_occasionally_wanted_to_kn
ow_about_wireless_power_transmission.shtml