1. WIRELESS POWER TRANSMISSION
Presented by
RADHIKA K
ROLL NO:-14C91D4312
BRANCH:-ELECTRONICS & ELECTRICAL ENGINEERING.

2. OVERVIEW INTRODUCTION DEFINITION HISTORY TYPES OF WPT
Atmospheric conduction method
Electrodynamic induction method
Advantages and disadvantage
Applications
Conclusion
References

3. INTRODUCTION
One of the major issues in power system is the losses occurring during the transmission and distribution of electrical power.
The percentage of loss of power during transmission and distribution is approximated as 26%.
The main reason for power loss during transmission and distribution is the resistance of wires used in grid.
According to the World Resources Institute (WRI), India’s electricity grid has the highest transmission and distribution losses in the world – a whopping 27-40%.
Tesla has proposed methods of transmission of electricity using electromagnetic induction.

4. DEFINITION As the word wireless means “without wire”.
Wireless energy transfer or wireless power is the transmission of electrical energy from a power source to an electric load without interconnecting man made conductors.
Wireless transmission is useful in cases where interconnecting wires are inconvenient, hazardous or impossible.

5. HISTORY
Sir NICOLAI TESLA was the first one to propose and research the idea of wireless transmission in 1899, since than many scholars and scientists have been working to make his dream a reality.
1899: Tesla continues wireless power transmission research in Colorado Springs and writes, "the inferiority of the induction method would appear immense as compared with the disturbed charge of ground and air method
1961: William C. Brown publishes an article exploring possibilities of microwave power transmission
2009: Sony shows a wireless electrodynamics-induction powered TV set, 60 W over 50 cm

6. METHODS
Different methods of transmission proposed by different scientist and scholars are:
Atmospheric conduction method of Tesla
2. Electrodynamic induction method:
Microwave method
Laser method

7. Atmospheric conduction method
In 1899 Sir NICOLAI TESLA and HEINRICH HERTZ powered a fluorescent lamp keeping it 25 miles away from source without using wire. Wireless power transmission experiments at WARDEN CLYFFE High frequency current, of a Tesla coil, could light lamps filled with gas (like neon). In this method a closed circuit is made using transmitter, ionized path between upper atmosphere and transmitter, second ionized path connecting receiver. The circuit back to the transmitter is completed through the earth .

8. Atmospheric conduction method
High potential is maintained at transmitter and receiver end as well. A high potential transmitter transmits an “electromotive impulse” through the ionized path to the upper atmosphere where it ionizes the air, and this air between the transmitter and receiver would conduct like a neon tube .

9. LIMITATIONS OF ATMOSPHERIC CONDUCTION METHOD
Economically challenging.
Periodic changes in atmospheric condition.
Maintaining high tower potential every time.

10. ELECTRODYNAMIC INDUCTION METHOD
We bring electromagnetic radiation into practice, which uses far field technique in order to achieve range into kilos, which includes two techniques:
LASERS
MICROWAVE

11. LASER transmission LASER is highly directional, coherent
Not dispersed for very long
But, gets attenuated when it propagates through atmosphere
Simple receiver
Photovoltaic cell
Cost-efficient

12. LASER METHOD
In the case of electromagnetic radiation closer to visible region of spectrum (10s of microns (um) to 10s of nm), power can be transmitted by converting electricity into a laser beam that is then pointed at a solar cell receiver.  This mechanism is generally known as "power beaming" because the power is beamed at a receiver that can convert it to usable electrical energy.
OPTICAL FIBRE
TRANSFORMER
LASER
CURRENT
CURRENT

13. MICROWAVE METHOD
Power transmission via radio waves can be made more directional, allowing longer distance power beaming, with shorter wavelengths of electromagnetic radiation, typically in the microwave range. A rectenna may be used to convert the microwave energy back into electricity. Rectenna conversion efficiencies exceeding 95% have been realized. Power beaming using microwaves has been proposed for the transmission of energy from orbiting solar power satellites to Earth.
The principle of Evanescent principle of Electromagnetic
Wave Coupling extends the
induction.

14. Applications Near-field energy transfer Far-field energy transfer
Electric automobile charging
Static and moving
Consumer electronics
Industrial purposes
Harsh environment
Far-field energy transfer
Solar Power Satellites
Energy to remote areas
Can broadcast energy globally (in future)

15. ADVANTAGES 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

16. DISADVANTAGES When microwaves are used, interference may arise
When LASERS are used, conversion is inefficient due to absorption losses.
It is radioactive in nature
Distance constraint , initial cost is high.
Field strength has to be under safety levels
High frequency signals should be supplied for air ionization which is not feasible.

17. CONCLUSION Transmission without wires- a reality Efficient
Low maintenance cost. But, high initial cost
Better than conventional wired transfer
Energy crisis can be decreased
Low loss
In near future, world will be completely wireless

18. References
S. Sheik Mohammed, K. Ramasamy, T. Shanmuganantham,” Wireless power transmission – a next generation power transmission system”, International Journal of Computer Applications (0975 – 8887) (Volume 1 – No. 13)
Peter Vaessen,” Wireless Power Transmission”, Leonardo Energy, September 2009
C.C. Leung, T.P. Chan, K.C. Lit, K.W. Tam and Lee Yi Chow, “Wireless Power Transmission and Charging Pad”
David Schneider, “Electrons unplugged”, IEEE Spectrum, May 2010
Shahrzad Jalali Mazlouman, Alireza Mahanfar, Bozena Kaminska, “Mid-range Wireless Energy Transfer Using Inductive Resonance for Wireless Sensors”
Chunbo Zhu, Kai Liu, Chunlai Yu, Rui Ma, Hexiao Cheng, “Simulation and Experimental Analysis on Wireless Energy Transfer Based on Magnetic Resonances”, IEEE Vehicle Power and Propulsion Conference (VPPC), September 3-5, 2008