WIRELESS POWER TRANSMISSION

PRESENTED BY

ASHISH KUMAR 1273520331

SHRI PRAKASH RAO 1273520330

AJAY KUMAR ARYA 1273520347

BITTO KR. GAUTAM 1273520305

RAJ KISHOR 1273520332

SUBMITTED TO

MISS PRIYA BAJPAI

(DEPT. OF ELECTRICAL ENGG.)

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OVERVIEW

• INTRODUCTION• DEFINITION• HISTORY• TYPES OF WPT

Atmospheric conduction methodElectrodynamic induction method

• Advantages and disadvantage• Applications• Conclusion

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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.

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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.

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HISTORY

• Nikola Tesla in late 1890s

• His vision for “World Wireless System”

• The 187 feet tall tower to broadcast energy

• All people can have access to free energy

• Due to shortage of funds, tower did not operate

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HISTORY

• Tesla 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 in to research after 100 years by a team led by Marin Soljačić from MIT. The project is named as ‘WiTricity’.

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METHODS

Different methods of transmission proposed by different scientist and scholars are:

1. Atmospheric conduction method of Tesla

2. Electrodynamic induction method:Microwave methodLaser method

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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 .

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ATMOSPHERIC CONDUCTION METHODHigh 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 .

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LIMITATIONS OF ATMOSPHERIC CONDUCTION METHOD

• Economically challenging.

• Periodic changes in atmospheric condition.

• Maintaining high tower potential every time.

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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

LASER TRANSMISSION

• Not dispersed for very long• LASER is highly directional, coherent• But, gets attenuated when it propagates through

atmosphere• Simple receiver• Photovoltaic cell• Cost-efficient

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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.

CURRENT CURRENT

LASER

TRANSFORMER

OPTICAL FIBRE

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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 Wave Coupling extends the principle of Electromagnetic induction

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APPLICATIONS

Near-field energy transferElectric automobile charging

○ Static and movingConsumer electronicsIndustrial purposes

○ Harsh environment Far-field energy transfer

Solar Power SatellitesEnergy to remote areasCan broadcast energy globally (in future)

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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

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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.

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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

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