WIRELESS POWER TRANSMISSION USING MICROWAVES

SUBMITTED BYRUDRA SANKAR BANDYOPDHYAY

(14EC63R08)RF AND MICROWAVE ENGINEERING

SEPTEMBER, 2014DEPARTMENT OF ELECTRONICS AND ELECTRICAL COMMUNICATION

ENGINEERINGINDIAN INSTITUTE OF TECHNOLOGY KHARAGPUR

CONTENTS

• Introduction• Problems in present scenario• History of Wireless Power Transfer• Description• Advancement• Merits, Demerits and Biological Effects• Conclusion• References

INTRODUCTION

• Process of transfer of power without the aid of man made conductors

• Power transfer takes places through free space via microwaves

• Used in cases where wires are inconvenient , hazardous or impossible

• Differs from wireless communication as noise is not a factor in this case

PROBLEMS IN PRESENT SCENARIO

• High transmission and distribution loss• India has highest loss at a whooping 27%• This process involves higher efficiency , low

power cost and protection from power theft

HISTORY OF WIRELESS POWER TRANSFER

• Nicola Tesla considered the father of wireless power transfer

• Tesla applied the principle of resonance to transmit power wirelessly

• William Brown made the first wireless powered helicopter

OPERATION PRINCIPLE

MAGNETRON

MAGNETRON CONTD…

TRANSMITTING ANTENNA

• Should have good directivity to avoid power losses.

• Microstrip patch, parabolic reflector or slotted waveguide antenna are best suited

• Efficiency of 95% was achieved using slotted waveguide antenna

TRANSMITTING ANTENNA CONTD…

• For efficient transmission pulses with power spectral density of a Gaussian function should be transmitted

• η= (π*Dt*Dr)/(4*λ*r)• High power handling capacity

RECEIVER

• The receiver used in this case is called a ‘RECTENNA’

• As it’s name implies it is a rectifier combined with an antenna

• The main function of a rectenna is conversion of the microwave power received into dc power for practical uses

Rectenna

DEVIATION FROM IDEAL BEHAVIOUR

• Due to input voltage lower than the lower than junction voltage or higher than breakdown voltage

• Possible Solutions • 1. Increasing Aperture• 2. Developing more accurate rectifying circuit.

Observations

EXPERIMENTAL RESULTSTYPE OF ANTENNA OPERATING FREQUENCY

(GHz)CONVERSION EFFICIENCY(%)

PRINTED DIPOLE 2.45 85

CIRCULAR PATCH 2.45 81

PRINTED SQUARE RHOMBIC

5.6 78

SQUARE PATCH 8.41 66

ADVANCEMENT

• Dyengo recently developed microwave based rectenna and rectifier circuit to achieve conversion efficiency of 90% at 2 GHz band

• Low pass filter rejects spurious noise by 50dBc• Heat dissipated as power in microwaves can

be recycled

SPACE BASED SOLAR POWER

• Very innovative approach to the use of microwave power transfer

• Research going on from early 1970s• Components• Solar energy collector• DC to microwave converter • Large antenna array to beam down

(Microwave) power to ground

SCHEMATIC

MICROARIAL VEHICLE

OPERATION

• Operating frequency of 5.8 GHz• Used to monitor places where human cannot

reach directly such as a disaster struck area• No need of refueling • Highly directed power using phased arrays

MERITS

• Remove physical infrastructure “Grids and Towers” • Cost effective (Remove cost of towers and cables)• During rain and after natural disaster it is often hard to

manage cables and towers so it removes this difficulty• Losses during transmission and distribution can be removed• Microwaves (electricity) are more environments friendly. It

does not involve emission of carbon gases. • Electricity bills using conventional supply can be cut to very

low. • Zero fuel cost

DEMERITS

• Biological effects associated with the wireless transmission of electricity due to the high frequency microwave signals is the first demerit of this technology

• This project is a onetime expense but it involves a lot of initial expenditure. It is expected that the price of receive electricity through this technology would decline overtime

• This technology is limited to the use of few technologies like solar satellites and Tesla grid

• The transmission of electric current through this mode is susceptible to security risks like cyber war fare

Biological impacts

• ELECTROHYPERSENSITIVITY• ALTERED PHYSIOLOGY• OXIDATIVE STRESS AND DAMAGED DNA

CONCLUSIONS

• This concept offers greater possibilities for transmitting power with negligible losses and ease of transmission than any invention or discovery heretofore made. Dr. Neville of NASA states “You don’t need cables, pipes, or copper wires to receive power. We can send it to you like a cell phone call – where you want it, when you want it, in real time”. We can expect with certitude that in next few years. Wonders will be brought by its applications if all the conditions are favourable.

References• http://cleantechindia.wordpress.com/2014/2/8/indias-electricity-transmission-

and-distribution-losses• Tesla, “ My inventions”, Ben Johnson , Ed,Austin , Hart Brothers,p.91,1982• ] S. Sheik Mohammed, K. Ramasamy, T. Shanmuganantham Wireless Power

Transmission – A Next Generation Power Transmission System ©2010 International Journal of Computer Applications (0975 – 8887) Volume 1 – No. 13

• Joshua Le-Wei Li- Wireless Power Transmission: State-of-the-Arts in Technologies and Potential Applications Proceedings of the Asia-Pacific Microwave Conference 2011

• Andreev, A.D. Directed Energy Div., Raytheon Missile Syst., Albuquerque, NM, USA Hendricks, K.J. Multicavity Magnetron With the “Rodded” Quasi-MetamaterialCathodePlasma Science, IEEE Transactions on (Volume:41 , Issue: 3 ), Page(s):620 - 627, IEEE Nuclear and Plasma Sciences Society,IEEE

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• John M. Osepchuk, “Health and safety issues for microwave powertransmission”, Solar Energy, vol. 56, 1996