wireless energy transfer_term paper

8/8/2019 Wireless Energy Transfer_Term Paper

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VINOD GUPTA SCHOOL OF MANAGEMENT, IIT KHARAGPUR

Wireless Energy TransferA Paper on Wireless Power Transmission

MBA 2010-2012

MANAGEMENT INFORMATION SYSTEMS TERM PAPER

INSTRUCTOR PROF. PRITHWIS MUKERJEE

SUBMITTED BY

SATHISHWARAN.R

10BM60079

MBA 2010-2012


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WIRELESS ENERGY TRANSFERNovember 9,

2010

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Table of Contents

ABSTRACT ................................ ................................ ................................ ................................ ......... 3

INTRODUCTION ................................ ................................ ................................ ................................ . 3

TECHNOLOGY EVOLUTION ................................ ................................ ................................ ................ 3

WIRELESS POWER TRANSMISSION KEY TECHNOLOGIES................................ ................................ . 5

APPLICATIONS................................ ................................ ................................ ................................ ... 7

CURRENT PLAYERS ................................ ................................ ................................ .......................... 10

CHALLENGES ................................ ................................ ................................ ................................ ... 12

WAY FORWARD ................................ ................................ ................................ .............................. 13

CONCLUSION................................ ................................ ................................ ................................ ... 13

REFERNCES................................ ................................ ................................ ................................ ...... 14


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ABSTRACT:

Wireless energy transfer is a very exciting technology which promises to radically change the way we

perform any activity. In this paper I like to explore the concept of transmitting power without using

wires. I will also like to discuss about how the technology developed and evolved over the years. The

paper will also cover the practical experiments conducted and look at a few companies that havesuccessfully brought out working products into the market. The advantages, disadvantages and the

biological impacts will also be covered in the paper. And finally the paper will also discuss the way

forward in the wireless power transmission field.

1. INTRODUCTION

Electricity has become so much a part and parcel of our life that we cannot now imagine living without

it. Day by day the usage of power is increasing at a higher rate as peoples economic wellbeing

improves. Conventional methods of producing power results in greenhouse gases and pollutes the

environment. However the technology for alternative sources of energy like solar, wind etc is still

considered costly. One method of improving the environment is by reducing the transmission and

distribution losses. As power consumption increases the transmission and distribution losses also

increases. According to official figures the transmission and distribution losses in India stand at 23 %.

However according to a paper by The Energy and Resource Institute (TERI) these losses have been

estimated to be of the order of 50 % in some states. Also as per a study by SBI Capital markets for

DVB the T&D losses have been estimated to be 58%. Though use of state of the art conductors will

reduce the losses, still a substantial amount of power produced is lost.

Also power theft has become rampant in many parts of the world. It is one of major contributors to the

distribution losses in the world. According to the ministry of power around 20% of power produced inIndia is stolen. Transmitting power through wires also poses serious problems of safety with exposed

live wires. These persisting and urgent problems can be overcome by the advent of new technology.

Wireless Power transmission is one such technology which can change the way we produce and

transmit power. Also we can one day be in a world without messy wires at home and on the street.

2. TECHNOLOGY EVOLUTION

The technology is based on the Amperes law showing that electric current produces a magnetic field.

In 1831 Michael Faraday developed the law of induction stating that an electromagnetic force is

induced in a conductor by a time-varying magnetic flux [1]. It was Nicholas Tesla that showed that

power can be transmitted without wires as early as 1891. He demonstrated wireless illumination of a

lamp at the Worlds Columbian Exposition in Chicago.


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Wardenclyffe tower also known as Tesla Tower was built to demonstrate the transmission of power

without wires. At the Worlds Fair in 1904, a 75W airship motor is driven by energy transmitted

through space at a distance of at

least 100 feet. William Brown

published a paper proposing

usage of microwave energy for

wireless power transmission in

1961. In 1964 he also

demonstrated a model helicopter

which receives its entire power

requirement from a microwave

beam. In 1968 Peter Glaser

proposes transferring solar

energy from space using power

beaming technology. This led to the concept of Solar Power satellites much later. Experiments in tensof kilowatts were carried out at the Goldstone Deep Space Communication complex as early as 1975.

In 1988 Auckland Uniservices, the commercial company of The University of Auckland, patents a

technology for a prototype for contactless power supply. Daifuku, a Japanese company and

Auckland Uniservices develops a wireless technology for car assembly plants and material handling

in 1989. In 1996 Auckland Uniservices commissions 1st

commercial IPT Bus in the world at

Whakarewarewa, in New Zealand. Splash power formed in the UK in 2001, the company uses

coupled resonant coils in a flat "pad" style to transfer tens of watts into a variety of consumer devices,

including lamp, phone, PDA, iPod. In 2005, Prof Boys' team at The University of Auckland refines 3-

phase IPT Highway and pick-up systems allowing transfer of power to moving vehicles in the lab. A

physics research group, led by Prof. Marin Soljacic at MIT powered a 60W light bulb with 40%

efficiency at a 2 metres (6.6 ft) distance with two 60 cm-diameter coils in 2007.

Bombardier launches Primove, Catenary -free tracks for trams and light rail vehicles in 2008.The

vehicle uses contactless power transfer and its electric supply components are invisible, hidden under

the vehicle and beneath the track. Wireless Power Consortium, a business alliance of 20 firms to

develop open standards for wireless charging also formed in the same year. Palm a division of HP

launched Palm Pre first mobile in the world to use wireless charging using Palm touchstone charger in

2009. LaserMotive won the 2009 NASAs Beam Power Challenge by transmitting over a kilowatt

more than several hundred meters. Recently Sony has announced electrodynamic-induction powered

TV set. Haier group too demonstrated completely wireless LCD television at CES 2010 based on

Marin Soljacic research. Also System on Chip group in University of British Columbia developed an

optimization tool for design of highly efficient wireless power transfer system using multiple coils. The

design was optimized for implantable application and power transfer efficiency of 82% was achieved.


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3. WIRELESS POWER TRANSMISSION KEY TECHNOLOGIES

Near Field is a wireless transmission technique that can cover a distance of a few times that of the

size of the device. The technique does pose some radiative losses and also there may be resistive

losses.

Induction Coupling:

Induction is based on faradays law which states that The induced electromotive force (emf) in any

closed circuit is equal to the time rate of change of the magnetic flux through the circuit . Faraday

explained that magnetic lines of force were responsible for such an effect. It is the concept of

Electromagnetic induction based on which the operation of generators, electric

motors, transformers, induction motors, and

most other electrical machines works. When

electrical current moves through a wire, it

creates a circular magnetic field around the wire.

Also when the wire is bent into a coil it amplifies

the magnetic field. When the number of loops is

increased the magnetic field around it also

increases. If a second coil of wire is placed

inside this magnetic field a current is generated

in the second wire.

By this principle several devices can be recharged at once. For E.g. Splashpower, a UK based

company had come up with a recharging pad Splashpad which uses induction principle. Electronic

devices are fitted with splashmodule (a built-in receiver) to recharge while they are resting on the pad.

These splashmodules have compatible coils and the circuitry that is necessary to deliver electricity to

those batteries.

Resonant Energy Transfer:

Resonant energy transfer is one of the near field technologies for energy transfer in which two coils

who is resonant on the same frequency. One of the advantages is that it does not require a magnetic

core unlike induction. Nicolas Tesla used the concept and developed the Tesla Coil which produced

high voltages and provided safety since magnetic field does not affect the living tissues. Also the

device could transmit power over higher distances than inductive coupling. Marin Soljacic, along with

researchers at MIT developed a theoretical analysis on the technology and showed that power can betransmitted to a few times the coil diameter with good efficiency using resonant energy transfer in

2006. For transmitting power through increased distances the inductive coupling method is inefficient

and a vast amount of energy is wasted in the form of resistive losses in the primary coil. If the both the

coils are resonant at the same frequency, significant power can be transmitted between them over a

higher range.


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ionized at high voltages between two electrodes. The technology uses an ultraviolet beam to ionize

the gases between the transmitter and receiver. Also conductivity of the earth can be utilised to

transmit power. The earth has radii about 4000 miles and is charged. Also there is the atmosphere

which is charged and a small stratum separates the two which is an insulator. One can create a

difference in potential between and earth and the atmosphere and the energy could be recovered.

Studies are going on how to make this technology though it is only theoretical stage right now.

4. APPLICATIONS

Electricity Transmission:

Wireless Power transmission can radically change the way we produce and transmit power. Electricity

generation, transmission and distribution face a lot of challenges. In a power hungry world we need to

reduce the losses in transmitting power so that we can use

power more efficiently. Power is a very valuable commodity in

the light of low availability of conventional sources of energy.

Also the renewable sources are more costly. Hence it

becomes imperative that we reduce the losses which stand

currently at around 30 - 50% in India.

Wireless power transmission has a higher efficiency and the

technology can be used for transmitting power through

microwaves or laser. Also the transmission is relatively safe

since there are no live wires that are required which prevents

accidental electrocution. Also one must have noticed the

crowded electric wires on the streets and around theresidential and commercial establishments. From the aesthetic

point of view wireless can provide a polished look to a city or home. Also the land acquisition which is

a burning issue currently can be reduced by adopting wireless transmission.

PoW

ering the Home:

Resonance Induction can replace the wires of the homes. A coil is placed with two capacitance plates

which can hold charge. The coil resonates when electricity flows through it. The resonance frequency

is equal to the product of inductance and capacitance generated. Another coil can be placed in any of

the devices a typical home uses. When this coil resonates with the same frequency electricity can

tunnel along to the coil in the form of electromagnetic waves. If there are other coils which resonate in

a different frequency then there will be no transfer of energy. One coil has the power to transfer

energy to many coils. This technology has the power to transmit electricity to all the devices in the

home.


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Wireless Charging:

Splashpower, a UK based company had come up with a pad or a table like arrangement which uses

the concept of induction to charge any

electronic device which placed on it. The

pad acts as the transmitter and the

appropriate circuit is placed on the

device which converts the magnetic field

into electricity. Also nowadays the

electronic toothbrush is charged using

the induction concept of transfer or

electric energy. Mobile phones, Laptops

and ipods could be charged without ever

connecting it to the wire.

Defence:

Wireless transmission can be used to

operate unmanned vehicles which do not

have to land in order to refuel. Power

can be directed at the vehicles and the onboard receiver can transform it into power for its use. There

are working prototypes that have been developed by Canadas communication research centre for

unmanned planes. Also microwave transmission can be used for destabilising an approaching enemy

like the Active Denial System.

Space based Solar PoX

er:

Space based solar power is harnessing suns energy in space and transmitting the same for earths

use. The solar panels can be placed on a satellite or even in the moon. The power thus generated

can be transmitted to the earth. Solar irradiance which is a measure of the solar power generation

capability is about 950 W/m2 on earth and about 1367 W/m2 for extraterrestrial. Also solar power on

earth can be harness only for about 12 maximum in a place and it depends largely on climatic

conditions. Whereas space offers 24 hours for harnessing the solar power. There are two problems

that need to be addressed, one is sending the solar power satellites and the other is the transmission

back to earth. The first requires advances in technology of satellite solar panels. Microwave powertransmission technique can be used for the transfer of this power to earth. The satellite can convert

the solar energy into microwave and direct them towards the earth surface. A receiver such as a

rectenna can collect this microwave and convert it back to electricity.

Many problems that are associated with generating solar power on earth like dependence on weather,

land acquisition, protection of wildlife can be entirely avoided. NASA has instituted the Space Solar

Power Exploratory Research and Technology program to look into the possibility of generating power


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in space. One of the mandates of the program is to formulate a plan for generating power using solar

satellites.

Nuclear power brings with it

questions of wastage and its

disposal. This concept doesnot have any such known

threats. Also when there are

major natural disasters like the

earthquake or tsunami it is

possible to direct the solar

satellite to the affected region

and provide as much of the

energy that is required. It has

the capability to provide instant

power supply to anywhere in

the world. Also with

geosynchronous satellites the

power can be transmitted 24

hrs a day. Also in conflict

zones like Iraq and Afghanistan the military can be supplied with power by just redirecting the

satellites. A mobile receiving station can then generate the required energy. The lives lost in

protecting he gallons of fuel needed for war can be saved.

Spacecraft Propulsion:

Beam powered propulsion can be used to transmit power to spacecraft or even the commercial

airlines. Fuel costs and the pollution associated with it are one of the major pain points concerning the

spacecraft. The beam could be a microwave beam or a laser beam. Fuel forms most of the weight

associated with a rocket and with a beam powered propulsion the fuel is left back on the earth

surface. Lasermotive beamed power up to 1 km during the NASA beaming competition. Also a laser

broom to clean up the space debris is also being planned.

Transport:

Researchers at the University of Auckland have successfully adapted the wireless power transmission

for vehicle movement and they call the technology Inductive Power transfer. One can place a track on

the roads of our highways and each vehicle or car is fitted with a receiver which converts the power

transmitted into electricity to power the electric motors that drive the vehicle. There is no requirement

to plug in to charge your electric vehicle.

Fuel is not required and by combining the solar satellites with the transport one can imagine a world

where global warming was a thing of the past.


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Contactless Smart Cards:

Contactless smart card is an IC chip which stores information and communicates with a terminal via

radio waves. These cards can be used as a means for identification like the recent Aadhar cards

planned for India. Also business transactions can be effected without human intervention. They have

been widely implemented in transport, security and electronic payments.

5. CURRENT PLAYERS

Bombardier:

In many streets around the world the trams and trains add to the visual pollution of the landscapes

and the architecture of the city. Bombardier has come up with Primove which provides catenary-free

tracks. The trams can be used for overhead as well as underground railway lines. It results in

eliminating the overhead wires and there is no wear and tear. The trams can be operated in all

weather conditions.

In a conventional system the power is taken from the overhead power lines. In Primove a cable is

placed along the tracks which are connected to the power supply network. A receiver coil is placed

underneath each vehicle which turns the magnetic field into electricity which is used to move the train.

Also since the power will flow only when the whole vehicle covers the cables it is safe also.

HeY

lett-Packard:

HP through its subsidiary Palm has introduced Palm pre which can be charged wirelessly using the

Palm Touchstone mobile charger. The phone can be charged just placing it on the dock. The dock

and phone work on the principle of resonant induction. The primary coil is available in the dock and

the phone carries the secondary coil. As the electricity flows through the doc it generates a magnetic

field which induces electricity in the secondary coil.

WiTricity:

Witricity is involved in developing the wireless power technology and they have come up with a

number of advancements in the technology. It is being guided by Marian Soljacic from MIT.


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Intel:

Researchers at Intel are working on transferring power without wires called Wireless Resonant

Energy Link (WREL). Justin Rattner the chief technology officer of Intel demonstrated the technology

at the Intel Developer Forum (IDF) in 2008. The demonstration included to light up a 60W bulb

wirelessly using a resonator.

Fulton Inno

ation:

Fulton innovation has developed the ecoupled technology for transferring wireless power. It is

operating under the parent company Alticor, Inc. The technology uses the principle of inductive

coupling between the primary and secondary coil. The technology automatically identifies whether a

device needs charging or not and also does not charge if i t is fully charged. The power transfer has

almost 98 % efficiency and Fulton has filed more than 220 patents on this technology.

Sony:

Sony has developed an efficient method for transmitting power based on resonance. Using the

system a 60W bulb can be lit at a distance of over 50 cm. It has also introduced the concept of

extender units which increases the distance without compromising on the efficiency which stands at

80%. It is planning to implement this technology in its future products.

One key technology that has been advanced is the use of extenders to increase the distance.The

extender units also resonate in the same frequency and there is minimum loss in the process. Sony

plans to implement it in it television sets and mobile phones being powered wirelessly.

Wireless Poa

er Consortium:

Wireless Power consortium is an alliance of 20 business firms which are involved in developing a

common standard for wireless power transfer. The consortium is in the process of developing a

universal standard for charging wirelessly so that various devices can be charged without need to

change the charging station. It aims to bring together different brands and devices so that any device

can be recharged using a common station. The open standard Qi was launched in 2009.


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LaserMotib

e:

LaserMotive is a Seattle based company which won the NASAs Power beaming competition winning

$ 900,000. The company is involved in developing systems which can transmit electricity over long

distances using laser. The beam is generated and the beam size is controlled. This beam moves

through the atmosphere or space and reaches the photovoltaic receiver. The receiver converts it into

electrical energy. There is no requirement for bulky equipment and wires. All it requires are

equipments at the transmitting and receiving end and nothing in between. There is no time as the

system can be set just by implementing

the two ends and does not require poles,

wires etc.

LaserMotive is also involved in

developing the technology for power

transmission for unmanned aerial

vehicles (UAV). Distance traversed in the

case of a UAV is limited by the fuel

requirement. The technology that has

been developed by lasermotive frees up

the UAV from landing to recharge its

batteries. The laser beam is sent from a

ground station and a receiver attached to

the UAV converts this beam into electrical energy. Lasermotive is also involved in developing

technology for defence purposes. Military bases can benefit from the technology as power can be

transmitted over long distances and there is no need to refuel in the midst of combat.

6. CHALLENGES

Uniform Standards for Wireless Charging:

The Wireless Power Consortium was formed to develop a uniform open standard so that devices can

work across charging stations. Though some big names like nokia, Phillips and Sanyo are part of the

consortium the open standard has not been implemented in many devices due to certain differences

in the standard. The Qi standard that has been must be adopted as a universal standard and

implemented across devices.

Biological Impacts:

A major misconception among many consumer public is that wireless transfer of power affects the

living tissues and causes damage. According to WHOM factsheet on Electromagnetic fields and

Public health continued exposure to magnetic fields well above 100 mT will lead to nervous system


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problems. However the power that will be used for wireless power transmission is well below that

which can affect the tissues. This challenge can be overcome by generating awareness among the

larger public.

Economic Impact:

The cost associated with wireless power transmission technology is very high. While the cost may be

high initially there is nil to small maintenance cost associated. Since there is no requirement of any

wires and charging equipment, material can be saved. Only a receiving station is required for each

house and transmitter to the devices, since all the devices will be enabled with receivers. Also it

reduces the transmission and distribution losses. There is no chance of any power theft which can be

a great saving for a country.

Laser Technology is inefficient:

Laser beam technology is a highly inefficient form of technology with efficiency as low as 40 to 50%.

The efficiency needs to be improved and more research needs to be carried out in this area.

7. WAY FORWARD

Nations have gone to war in search of fuels to satisfy their energy needs. If the solar power satellite

technology is implemented there will not be any power scarcity. Also if the wireless power is

implemented in transport by laying cables under the roads this power can be used to run vehicles.

Also the same power can be used to charge our homes. From flying aircraft to combating war the

whole picture could change. Also since there is not carbon emission we can free our world from the

effects of global warming. The world should come together to set up research centres and

organizations to take the technology forward.

8. CONCLUSION

The transmission of electricity without wires has become a reality thanks to the advancement of

technology. It has the power to change radically the way we perform any activity. From Teslas

Wardenclyffe tower to the present laser beam from lasermotive technology has come a long way. Let

us hope that in the interest of all the people of the world this technology is adapted and implemented

across the world in the near future.


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9. REFERENCES:

y http://en.wikipedia.org/wiki/Wireless_energy_transfer

y http://www.powermin.nic.in/JSP_SERVLETS/internal.jsp

y http://www.uniservices.co.nz/LinkClick.aspx?fileticket=9i4tKmVqhmY%3d&tabid=345

y http://www.bombardier.com/en/transportation/sustainability/technology/primove-catenary-free-

operation

y http://lasermotive.com/

y http://www.witricity.com/

y http://en.wikipedia.org/wiki/ECoupled

y http://www.who.int/mediacentre/factsheets/fs322/en/index.html

y

http://www.sony.net/SonyInfo/News/Press/200910/09-119E/index.html

y http://blogs.intel.com/research/2008/08/you_have_to_see_thiswireless_p.php

y http://www.teriin.org/upfiles//pub/papers/ft33.pdf

y http://online.wsj.com/article/SB124885874162589595.html

y http://www.howstuffworks.com/wireless-power.htm

wireless energy transfer_term paper

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