PROJECT REPORT ON WIRELESS POWER TRANSMISSION

A Project Report On Wireless Power Transmission in PDF Format
desiged by Vipul Kumar Jangir.

1. A
MajorProject
“WirelessPowerTransmission”
Submittedthepartialfulfillmentforawardthedegreeof
BachelorofTechnology
In
ElectricalEngineering
From
RajasthanTechnicalUniversity,Kota
Session2019-2020
GuidedBy SubmittedBy
Mr.YogeshVerma VipulKumarJangir
DepartmentofElectricalEngg. SumitKumar
SandeepSaini
RanjeetVerma
RajuLalMeena
RajeshJangid
PradeepDan
IVB.Tech.VIIISem
Submittedto
Mr.RahulGarg
HeadofDepartment
DepartmentofEelectricalEngineering
MAHARISHIARVINDINSTITUTEOFENGINEERING&
TECHNOLOGY,JAIPUR

2. I
ACKNOWLEDGEMENT
WewouldliketoexpressourgratitudeandthankstoMaharishiArvindInstituteOf
Engineering&Technology,forprovidinganopportunityforfulfillingourmostcherished
desireofreachingourgoalsandthushelpingtopaveabrightcareerforus.
WewouldliketosincerelythankourHODandguide,Mr.RahulGarg,Departmentof
ElectricalEngineering,MAIET,forhisencouragement,supportandhisvaluableguidance
andinput,andforhelpinguswiththeprojectandpreparethereportforthesame.
WealsothankalltheFacultymembersandtechnicalstaffoftheDepartmentofElectrical
Engineeringfortheircontinuedsupportandguidanceandinhelpingussuccessfullycomplete
outproject.
Wewouldliketothankourparentsandfriendsforextendingfortheirhandsdirectlyor
indirectlyateveryjunctureofneed.

3. II
ABSTRACT
Thetransmissionofelectricalenergyfromsourcetoloadforadistancewithoutany
conductingwireorcablesiscalledWirelessPowerTransmission.Theconceptofwireless
powertransferwasrealizedbyNikolaTesla.Wirelesspowertransfercanmakearemarkable
changeinthefieldoftheelectricalengineeringwhicheliminatestheuseconventionalcopper
cablesandcurrentcarryingwires.Daybydaynewtechnologiesaremakingourlifesimpler.
Wirelesschargingthroughresonancecouldbeoneofthenexttechnologiesthatbringthe
futurenearer.Inthisprojectithasbeenshownthatitispossibletochargelowpowerdevices
wirelesslyviainductivecoupling.Itminimizesthecomplexitythatarisesfortheuseof
conventionalwiresystem.Inaddition,theprojectalsoopensupnewpossibilitiesofwireless
systemsinourotherdailylifeuses.
Inthisprojectwewilltrytoachievetransmissionofpowerthroughwirelesstechnology.The
mainapplicationofthismightbeseeninthetransmissionofenergyfromsatellitesolarpower
plants.ThemethodsoftransmittingpowerthroughwirelesstechnologyincludeRIC
(ResonantInductiveCoupling),microwaveandlasertransmissiontechniques.Ouraimisto
developasystemforpowertransmissionusingoneoftheabovetechniquesmainlyRICor
Microwavetransmission.

4. III
TableofContents
CHAPTER1INTRODUCTION....................................................................................1
1.2FieldRegions:........................................................................................................1
CHAPTER2LITERATURESURVEY........................................................................3
2.2Tesla’sExperiment:...............................................................................................3
CHAPTER3OVERVIEW............................................................................................4
CHAPTER4WITRICITY.............................................................................................5
4.1WhatWiTricityisnot?..........................................................................................5
4.2WhatWiTricityis?................................................................................................6
4.3WhyWiTricity?.....................................................................................................6
4.4Range:....................................................................................................................7
4.5EvanescentWaves:................................................................................................7
4.6Howitworks:........................................................................................................8
CHAPTER5BASICCONCEPTOFWIRELESSPOWERTRANSFER....................9
5.1InductiveCoupling................................................................................................9
5.2InductiveCharging................................................................................................9
CHAPTER6INDUCTANCEOFCOILANDCOILDESIGN..................................11
6.3Lossesincoil:......................................................................................................12
6.4BlockDiagram.......................................................................................................12
6.5CircuitDiagram...................................................................................................13
6.6Componentsusedintransmitter:.........................................................................14
6.7Componentsusedinreceiver:.............................................................................15
CHAPTER7TRANSMITTER....................................................................................16
7.1Workingoftransmittercircuit:............................................................................16
7.2DCsupply:...........................................................................................................16

5. IV
7.3Oscillatorcircuit:.................................................................................................16
7.4Workingofoscillatorcircuit:..............................................................................16
7.5Transmittercoil:..................................................................................................17
CHAPTER8RECEIVER............................................................................................18
8.1WorkingofReceiver:..........................................................................................18
8.2Receivercoil:.......................................................................................................18
8.3Rectifier:..............................................................................................................18
8.4Operationofbridgerectifier:...............................................................................18
8.5VoltageregulatorIC:...........................................................................................19
8.6Buckconverter:...................................................................................................19
CHAPTER9PCBLAYOUT.......................................................................................20
9.1Transmitter:.........................................................................................................20
9.2Receiver:..............................................................................................................20
CHAPTER10WIRELESSPOWERTRANSMISSION.............................................21
10.5FarFieldMethods:............................................................................................22
CHAPTER11MAGNETICRESONANCEINDUCTION........................................25
11.1ResonantInduction:...........................................................................................25
11.2TermsrelatedtoResonance:.............................................................................26
11.3ImplementationofMRIinourproject:.............................................................27
CHAPTER12WIRELESSPOWERTRANSMISSIONUSING
RESONANTINDUCTIVECOUPLING......................................................................28
CHAPTER13OSCILLATORDESIGN.....................................................................30
CHAPTER14ANTENNADESIGN...........................................................................34
CHAPTER15FINALASSEMBLY............................................................................39
CHAPTER16RESULTS............................................................................................45
CHAPTER17CONCLUSION....................................................................................48

6. V
CHAPTER18POSSIBLEAPPLICATIONSANDFUTUREWORK......................49
17.1Applications:.....................................................................................................49
17.2Futurework:......................................................................................................49
CHAPTER18REFERENCES.....................................................................................51
CHAPTER19BIOGRAPHY………………………………………………………..58
APPENDIX…………………………………………………………………………..59

7. VI
LISTOFFIGURES
Figure1:Singlesourcecoilpoweringmultipledevices………………………………6
Figure2:Theratioofthedistancebetweenthetwoobjects…………………………..7
Figure3:WiTricitycircuitusedtoglowLEDbulb…………………………………...8
Figure4:InductiveCouplingwithFourComponentFluxes………………………….9
Figure5:SingleLayerCoil…………………………………………………………11
Figure6:BlockDiagram……………………………………………………………..12
Figure7:CircuitDiagramOfTransmitter…………………………………………..13
Figure8:CircuitDiagramOfReceiver………………………………………………13
Figure9:TRANSMITTER…………………………………………………………16
Figure10:BlockDiagramOfTheReceiverModule…………………………….18
Figure11:PCBLayoutOfTransmitter……………………………………….20
Figure12:PCBLayoutOfReceiver…………………………………………..20
Figure13:Comparison……………………………………………………………24
Figure14:BlockDiagramOfWirelessPowerTransmissionUsingResonant
InductiveCoupling…………………………………………………………………..28
Figure15:CircuitDescriptionOfRoyerOscillator………………………………31
Figure16:DesignOfRoyerOscillator…………………………………………….32
Figure17:CoilDesign1………………………………………………………..35
Figure18:CoilDesign2………………………………………………………….36
Figure19:CoilDesign3………………………………………………………….37
Figure20:HighFrequencyConverter1…………………………………………..40
Figure21:HighFrequencyConverter2…………………………………………41
Figure22:HFConverterClosed1……………………………………………….42
Figure23:HFConverterClosed2………………………………………………..43

8. VII
Figure24:TransmissionandReceivingcoils…………………………44
Figure25:CROWaveformsAtNoLoadInput………………………..45
Figure26:CROWaveformsAtNoLoadOutput………………………46
Figure27:CROWaveformsAtNoLoadedOutput……………………..47
Figure28:PossibleApplicationsAndFutureWork………….48

9. VIII
LISTOFTABLES
Table1:Componentsusedintransmitter……………………………………14
Table2:Componentsusedinreceiver……………………………………….15
Table3:Componentsareusedtomaketheoscillator………………………33
Table4:Comparisonofthedesigns…………………………………….38

10. 1
CHAPTER1INTRODUCTION
1.1HISTORY
Wirelesspowertransfer(WPT)isthetransmissionofelectricalpowerfromapowersourceto
aconsumingdevicewithoutusingdiscretemanmadeconductors.Researchershave
developedseveraltechniquesformovingelectricityoverlongdistancewithoutwires.Some
existonlyastheoriesorprototypesbutothersarealreadyinuse.Thispaperprovidesthe
techniquesusedforwirelesspowertransmission.Itisagenerictermthatreferstoanumberof
differentpowertransmissiontechnologiesthatusetime-varyingelectromagneticfields.
Wirelesstransmissionisusefultopowerelectricaldevicesincasewhereinterconnecting
wiresareinconvenient,hazardous,orarenotpossible.ForexamplethelifeofWSNisits
nodewhichconsistsofseveraldevicecontrollers,memory,sensors,actuators,transceivers
andbatteryandbattery.Thetransceivercanoperateinfourstates,i.e.
1)Transmit
2)Receive
3)Idleand
4)Sleep.
Themajorenergyproblemofatransmitterofanodeisitsreceivinginidlestate,asinthis
stateitisalwaysbeingreadytoreceive,consuminggreatamountofpower.However,the
batterhasaveryshortlifetimeandmoreoverinsomedevelopmentsowingtobothpractically
andeconomicallyinfeasibleormayinvolvesignificantresiststohumanlife.Thatiswhy
energyharvestingforWSNinreplacementofbatteryistheonlyanduniquesolution.In
powerbyelectromagneticfieldsacrossaninterveningspacetooneormorereceiverdevices,
whereitisconvertedbacktoelectricpowerandutilized.Incommunicationthegoalisthe
transmissionofinformation,sotheamountofpowerreachingthereceiverisunimportantas
longasitisenoughthatsignaltonoiseratioishighenoughthattheinformationcanbe
receivedintelligibly.Inwirelesscommunicationtechnologies,generally,onlytinyamountsof
powerreachthereceiver.Bycontrast,inwirelesspower,theamountofpowerreceivedisthe
importantthing,sotheefficiency(fractionoftransmittedpowerthatisreceived)isthemore
significantparameter.
1.2FieldRegions:
Electricandmagneticfieldsarecreatedbychargeparticlesinmattersuchaselectrons.A
stationarychargecreatesanelectrostaticfieldinthespacearoundit.Asteadycurrentof
charge(directcurrent,DC)createsastaticmagneticfieldaroundit.Theabovefieldscontain
energy,butcannotcarrypowerbecausetheyarestatic.Howevertime-varyingfieldscancarry
power.Acceleratingelectriccharge,suchasarefoundinanalternatingcurrent(AC)of
electronsinawire,createtime-varyingelectricandmagneticfieldsinthespacearoundthem.
Thesefieldscanexertoscillatingforceontheelectronsinareceiving“antenna”,causing
themtomovebackandforth.Theserepresentalternatingcurrentwhichcanbeusedtopower
aload.Theoscillatingelectricandmagneticfieldssurroundingmovingelectricchargesinan
antennadevicecanbedividedintotworegions,dependingondistance.Rangefromthe
antenna.Differenttechnologiesareusedfortransmittingpower:Near-fieldornon-radiative
region-Thismeanstheareawithinaboutwavelength(λ)oftheantenna.

11. 2
1.3IssuesinWPT
Oneofthemajorissueinpowersystemisthelossesoccursduringthetransmissionand
distributionofelectricalpower.Asthedemandincreasesdaybyday,thepowergeneration
increasesandthepowerlossisalsoincreased.Themajoramountofpowerlossoccursduring
transmissionanddistribution.Thepercentageoflossofpowerduringthetransmissionand
distributionisapproximatedas26%.
Themainreasonforpowerlossduringtransmissionanddistributionistheresistanceofwires
usedforgrid.Theefficiencyofpowertransmissioncanbeimprovedtocertainlevelbyusing
highstrengthcompositeoverheadconductorsandundergroundcablesthatusehigh
temperaturesuperconductor.But,thetransmissionisstillinefficient.AccordingtoWorld
ResourcesInstitution(WRI),India’selectricitygridhasthehighesttransmissionand
distributionlossesintheworldawhopping27%.NumberspublishedbyvariousIndian
governmentagenciesputthatnumberat30%,40%andgreaterthan40%.Thisisattributedto
technicallosses(grid’sinefficiencies)andtheft.Theabovediscussedproblemcanbesolved
bychooseanalternativeoptionforpowertransmissionwhichcouldprovidemuchhigher
efficiency,lowtransmissioncostandavoidpowertheft.MicrowavePowerTransmissionis
oneofthepromisingtechnologiesandmaybetherighteousalternativeforefficientpower
transmission.
1.4ResonantInductiveCoupling
Resonance,suchasresonantinductivecoupling,canincreasethecouplingbetweenthe
antennasgreatly,allowingefficienttransmissionatsomewhatgreaterdistance,althoughthe
fieldsstilldecrease,althoughthefieldsstilldecreaseexponentially.Thereforetherangeof
near-fieldsdevicesisconventionallydividedintotwocategories:Shortrange-uptoaboutone
antennadiameter:Drange≤Dant.Thisistherangeoverwhichordinarynon-resonant
capacitiveorinductivecouplingcantransferparticleamountsofpower.
Mid-range-upto10timestheantennadiameter:range≤10Dant.Thisisrangeoverwhich
ordinarynon-resonantcapacitiveorinductivecouplingcantransferpracticalamountofpower.
Far-fieldorradiativeregion:Beyondabout1wavelength(λ)ofantenna,theelectricand
magneticfieldsperpendiculartoeachotherandpropagateasanelectromagneticwave;
exampleareradiowaves,microwave,orlightwaves.Thispartoftheenergyisradiative,
meaningitleavestheantennawhetherornotthereisareceiverabsorbsit.Theportionof
energywhichdoesnotstrikethereceivingantennaisdissipatedandlosttothesystem.The
amountofpoweremittedaselectromagneticwavesbyanantennadependsontheratioofthe
antenna’ssizeDanttothewavelengthofwavesλ,whichisdeterminedbythefrequencyf
wherethefrequency:λ=c/f.Atlowfrequenciesfwheretheantennaismuchsmallerthanthe
sizeofthewaves,Dant<<λ,verylittlepowerisradiated.Thereforethenear-fielddevices
above,whichuselowerfrequencies,radiatealmostnoneoftheirenergyaselectromagnetic
radiation.AntennasaboutthesamesizeasthewavelengthDant≈λsuchasmonopoleor
dipoleantennasradiatepowerefficiently,buttheelectromagneticwavesareradiatedinall
directions.Soifthereceivingantennaisfaraway,onlyasmallamountoftheradiationwill
hitit.Therefore,thesecanbeusedforshorterrangeinefficientpowertransmissionbutnotfor
shortrangetransmissionbutforlongrangetransmission.However,unlikefields,
electromagneticradiationcanbefocusedbyreflectionorrefractionintobeams.Byusinga
highgainantennaoropticalsystemwhichconcentratestheradiationintoanarrowbeam
aimedatthereceiver,itcanbeusedforlongrangepowertransmission.FromtheRayleigh
criterion,toproducethenecessarytofocusasignificantamountoftheenergyonadistant
receiver,anantennamustbemuchlargerthanthewavelengthofthewaveusedDant>>λ=
c/f.Practicalbeampowerdevicesrequirewavelengthinthecentimetreregionorbelowinthe
correspondingtofrequenciesabove1GHz,inthemicrowaverange.

12. 3
CHAPTER2LITERATURESURVEY
2.1HISTORY
In1826Andre-MarieAmperedevelopedampere’scircuitallawshowingthatelectriccurrent
producesamagneticfield.MichaelFaradaydevelopedFaraday’slawofinductionin1831,
describingtheelectromagneticforceinducedinaconductorbyatime-varyingmagneticflux.
In1862JamesClerkMaxwellsynthesizedtheseandotherobservations,experimentsand
equationsofelectricity,magnetismandopticsintoaconsistenttheory,derivingMaxwell’s
equations.Thissetofpartialdifferentialequationsformsthebasisformodern
electromagneticincludingthewirelesstransmissionofelectricalenergy.
2.2Tesla’sExperiment:
TeslawasdemonstratingwirelesspowertransmissioninalectureatColumbia
College,NewYork,in1891.ThetwometalsheetsareconnectedtohisTeslacoil
oscillator,whichappliesahighfrequencyoscillatingvoltage.Theoscillatingelectric
fieldsbetweenthesheetsionizesthelowpressuregasinthetwolongGeisslertubes
heisholding,causingthemtoglowbyfluorescence,similartoneonlights.
ExperimentinresonantinductivetransferbyTeslaatColoradoSprings1899.Thecoil
isinresonancewithTesla’smagnifyingtransmitternearby,poweringthelightbulbat
bottom.InventorNikolaTeslaperformedthefirstexperimentsinwirelesspower
transmissioninwirelesspowertransmissionattheturnofthe20thcentury,andmay
havedonemoretopopularizetheideathananyotherindividual.Intheperiod1891to
1904heexperimentedwithtransmittingpowerbyinductiveandcapacitivecoupling
usingspark-excitedradiofrequencyresonanttransformer,nowCalledTeslacoils,
whichgeneratedhighACvoltages.Withthesehewasabletotransmitpowerforshort
distanceswithoutwires.IndemonstrationsbeforetheAmericanInstituteofElectrical
Engineersandthe1893ColumbianExpositioninChicagohelitlightbulbsfrom
acrossastage.HefoundhecouldincreasethedistancebyusingareceivingLCcircuit
tunedtoresonancewiththetransmitter’sLCcircuit,usingresonantinductive
coupling.AthisColoradospringslaboratoryduring1899-1900,byusingvoltagesof
theorderof10megavoltsgeneratedbyanenormouscoil.Hewasabletolightthree
incandescentlampsatadistanceofaaboutonehundredfeet.Theresonantinductive
couplingwhichTeslapioneeredisnowafamiliartechnologyusedthroughout
electronicsandiscurrentlybeingwidelyappliedtoshort-rangewirelesspower
systems.

13. 4
CHAPTER3OVERVIEW
3.1Advantages
Itmakesdevicesmoreconvenientandthusmoredesirabletopurchasers,byeliminatingthe
needforapowercordorbatteryreplacement.·Thepowerfailureduetoshortcircuitand
faultoncableswouldneverexistintransmission.·Reductionofe-wastebyeliminatingthe
needofpowercords.·Wirelesschargingoffersnocorrosionastheelectronicsareall
enclosed,awayfromwateroroxygenintheatmosphere.
3.2Disadvantages
ThecapitalcostforparticleimplementationofWPTseemsveryhigh.·WPTmaycause
interferencewithpresentcommunicationsystems.·Lessefficiencycomparedtotraditional
charging.
3.3BiologicalImpacts
Commonbeliefsfeartheeffectofmicrowaveradiation.Butthestudiesproventhatthe
microwaveradiationlevelwouldbeneverhigherthanthedosereceivedwhileopeningthe
microwaveovendoor,meaningitslightlyhigher.
3.4Applications
WPTfindsitsapplicationsinavariousfields.Itcanbeusedinmovingtargetssuchasfuel
freeairplanes,fuelfreeelectricvehicles,movingrobotsandfuelfreerackets,automatic
wirelesschargingformobilerobots,cordlesstoolsandinstrumentwhicheliminatescomplex
mechanisms,andlabourintensivemanualrechargingandbatteryreplacement.·Another
applicationofWPTissolarpowersatellites,energytoremoteareas,broadcastenergy
globally.WPTareusedforUbiquitouspowersource,RFPowerAdaptiveRectifyingCircuits
(PARC).
3.5FutureScope
Witricityisbuildinganearfieldwirelesschargingapparatusforconsumerdeviceswiththe
helpoftheHaiergroup,aChineseelectronicsmanufacturer.Witricitydemonstratedthis
technologybywirelesspoweringa32inchtelevisionatadistanceofsixfeet.Delphi
AutomotivesisworkingwithWitricitytodevelopawirelesschargingsystemforelectriccars.
Thegroundbreakingtechnologywillenabletoautomotivemanufacturertointegratewireless
chargingintothedesignofhybrid&electricvehicles.Thereisanotherstandardprotocolfor
chargingmobilephoneinitiatedbytheWirelessPowerConsortium.

14. 5
CHAPTER4WITRICITY
4.1WhatWiTricityisnot?
4.1.1TraditionalMagneticInduction:
ThoughWiTricitylooksliketraditionalmagneticinduction,itisnotthesame.Inthe
traditionalmagneticinductionsystem,conductivecoilstransmitpowertoeachother
wirelesslyoververyshortdistances.Inthissystemtwocoilsmustbeveryclosetoeachother
andmayevenoverlap.“Theefficiencyofpowertransferdropsbyordersofmagnitudewhen
distancebetweenthecoilsbecomeslargerthantheirsizes”.Examplesoftraditionalmagnetic
inductionpowerexchangeareelectronictoothbrushes,chargingpads,etc.
4.1.2RadioactivePowerTransfer:
Tofacilitatetransferofinformationoverawidespectrumtomultipleusers,radiofrequency
energyisbroadcastedthroughradiation.Eachradioorwirelessreceiverunitneedstohavean
amplifiersectionwithexternalpowersupplysoastoreceivetheinformation.Radio
transmissioniscapableoflowpowerinformationtransfer,butineffectiveincaseofpower
transferasmostofthepowerislostinfreespaceduetoradiation.Otheralternativesofpower
transfersuchasfeedingmorepowerintothetransmittersorusingdirectedradiationsusing
antennascausehighriskofinterferencewithotherradiofrequencydevicesandalsoposea
safetyhazardforlivingorganismswhichcomeinbetweentheline-of-sightofthetransmitter
andthereceiver.Theselimitationsmakeradiotransmissionanimpracticalmeansofwireless
powertransferforconsumer,commercial,oranyindustrialapplication.
Theothermeansofwirelesspowertransferincludevisibleandinvisiblelightwavessuchas
sunrays,laserbeams,etc.Thesunbeinganexcellentsourceoflightenergy,extensive
researchisbeingcarriedouttocapturethisenergyandconvertittoelectricalenergyusing
photovoltaiccells.Acollimatedbeamoflaserrayscanbeusedtotransferenergyinatargeted
way.Butitrequiresaclearline-of-sightbetweenthetransmitterandthereceivertoinsure
safeandefficienttransmission.
4.1.3MRI:
MRIstandsforMagneticResonanceImagingusedtodevelopdiagnosticimagesofsoft
tissuesinthehumanbody.ItcannotbecomparedwithWiTricity,i.e.,ResonantMagnetic
Couplingastheybothhavecontrastingprinciples.TheprocedureofMRImakesuseofa
strongDCmagnetwhichorientsthemagneticfieldsofatomspresentinthehumantissues
andalsoaffectstheradiofrequencyfieldssoastomanipulatethoseatomsinadesiredwayto
obtainclearimagesofthetissuestructure.

15. 6
4.2WhatWiTricityis?
ThetermWiTricityisablendofthewords‘wireless’and‘electricity’.Itisaformofnon
radiativepowertransfer.Mostoftheothertechniquesdiscussedaboveuseradiativeformsof
powertransfer.WiTricityisdifferentasitusesmagneticcoupling.Inthisaclearlineofsight
betweentheemitterandreceiverisnotneeded.WiTricityisalsoasafemodeofpower
transferastheinteractionbetweenthemagneticfieldsandbiologicalorganismsisnot
hazardous.
TheseattributesmakeWiTricityaformofpotentialtechnologywhichcanbeusedtotransfer
electricity/powerbetweenelectricalsourcesandreceiverswithouttheuseofwiresorcables.
Keepingcertainfactorsinmindandalsoensuringthattheelectromagneticfieldisstrong
enoughtoallowreasonablepowertransfer,itispossibletotransferpoweroveracertain
amountofdistance.“Thisispossibleifboththeemitterandthereceiverachievemagnetic
resonance”.Wirelesstransmissionofenergyisveryhelpfulinareaswhereuninterruptedand
instantaneouspowerisrequiredandusingwiresinconvenient,hazardous,orimpossible.
4.3WhyWiTricity?
Imagineaworldinwhichyoudonotrequiretheuseofanykindsofcordstopowerorcharge
yourelectronicdevices.Everythingfromyourlamptoyourcellphoneandevenyour
televisionsetcanbechargedorpoweredwithoutcords.Thiscanbemadepossiblewiththe
useofWiTricity.Centuriesago,scientistswouldhavelaughedattheideaofwireless
communication,buttodaywecannotimagineaworldwithoutcellphonesandtheinternet.
Therapidgrowthanddevelopmentintheresearchofwirelesstechnologyhashelpedthe
worldthinkoutofthebox.Nowitistimefortheworldtothinkevenfurtherandexplorethe
worldofelectronicswhichcanbepoweredwirelesslythroughthetechnologyprovidedby
WiTricity.Byusingasinglesourcecoil,multipledeviceswithreceivingcoilcanbepowered.
Withwidespreaduseitcouldeveneliminatecostlybatteriesandtherewillbenomoremessy
wires.
Figure1:Singlesourcecoilpoweringmultipledevices

16. 7
4.4Range:
WiTricitytechnologyisdesignedfor“mid-range”distances,whichweconsidertobe
anywherefromacentimetertoseveralmeters.Theactualoperatingrangeforagiven
applicationisdeterminedbymanyfactors,includingpowersourceandcapturedevicesizes,
desiredefficiency,andtheamountofpowertobetransferred.
Asshownbelow,theratioofthedistancebetweenthetwoobjectsandtheirradius
increases,theratioofcouplingcoefficientandresonancewidthsdecreases.
Figure2:Theratioofthedistancebetweenthetwoobjects
Heretheratioofcouplingcoefficientandresonancewidthrepresentsefficiency.Using
differentmaterialswillallowustohavelesslossatabetterdistance/radiusratio,becauseas
perequationspermittivityofmediumisalsoanimportantfactor.
4.5EvanescentWaves:
Anearfieldstandingwavewhoseintensitydecaysexponentiallyasittravelsadistancefrom
thepointofitsoriginiscalledasanevanescentwave.Thesewavesobeythepropertyof
generalwaveequations.Theyareoriginatedattheboundarybetweentwomediahaving
differentwavemotionpropertiesandtheirintensityismaximumwithinone-thirdofa
wavelengthfromthesurfaceofoccurrence.Evanescentwavesareobservedinareasof
electromagneticradiation,quantummechanics,acousticsandstringwaves.
Inthefieldofopticsandacoustics,whenthewavestravelinginamediumstriketheboundary
atananglegreaterthanthecriticalangle,theyundergototalinternalreflectionwhichgives
risetoevanescentwaves.Physically,sincetheelectricandmagneticfieldsarecontinuousata
boundaryofthemedium,theevanescentwavesaregenerated.Similarly,inthecaseof
quantummechanics,theparticlemotionwhichisrepresentedbytheSchrödinger
wave-functionisnormaltotheboundaryandiscontinuous.

17. 8
4.6Howitworks:
Themostsimpleandcommonexampleofacousticresonanceisshatteringofawineglassby
anoperasinger.Whenidenticalwineglassesarefilledwithdifferentquantityofwine,they
eachhavedifferentresonancefrequencies.Now,whenanoperasingersingsandacertain
voicepitchmatchestheresonantfrequencyofaspecificglass,theacousticenergy
accumulatedbytheglassissufficientforittoexplode,whileotherglassesremainunaffected.
Thus,thereexistsastronglycoupledregimeinallsystemsofcoupledresonatorsandhighly
efficientenergytransferisachievedwhenoperatedinthisregime.
SinceWiTrcityoperatesinanon-radiativefield,thereisanadvantagethatevenifthe
receivingcoildoesnotpickupallthepower,theresidualpowerremainsinthevicinityofthe
sendingcoilandisnotlostintheenvironmentduetoradiation.TheWiTricitycircuitis
designedinawaythatthefrequencyofthealternatingcurrentisincreasedtotheresonant
frequency.Thetravellingcurrentinducesmagneticandelectricfieldsintheinductorand
capacitorloopsrespectivelywhichextendsupto5metersaroundthedevice.Thismagnetic
fieldinducesanelectriccurrentintheinductorloopofanymobilegadgethavingthereceiver
coilwiththesameresonantfrequency.Thusboththecircuitsresonatetogetherandenergy
transferisachieved.
Figure3:WiTricitycircuitusedtoglowLEDbulb.
TheabovecircuitisagoodexampleoftheWiTricitysystem.Ascanbeseenfromthe
diagram,itusestwocoilswhicharetunedatthesameresonantfrequency.Themainsupplyis
giventotransformerwhichinduceshighfrequencyAContheprimarycoil.Whensecondary
coilcomesinthevicinityoftheprimarycoil,powergetstransferredfromprimaryto
secondary.Powertransfertakesplaceashighfrequencygetsinducedonthesecondarycoil.
Thesignalatthesecondarycoilisrectifiedandgiventotheload.
SomethingtheMITteamrealizedisthatifevanescenttails(tailsofenergy)aremadelarger
thanthesizeoftheobjects,energycouldbeconservedandenergylostduetoradiationwillbe
less.Thisissomethingthattheydiddifferentlyfrommanyprevioustests,becausemostofthe
time,longevanescenttailsleadtohigherinterferencebetweenthedevices.

18. 9
CHAPTER5BASICCONCEPTOFWIRELESSPOWER
TRANSFER
5.1InductiveCoupling
InductiveorMagneticcouplingworksontheprincipleofelectromagnetism.Whenawireis
proximitytoamagneticfield,itgeneratesamagneticfieldinthatwire.Transferringenergy
betweenwiresthroughmagneticfieldsisinductivecoupling.
Ifaportionofthemagneticfluxestablishedbyonecircuitinterlinkswiththesecondcircuit,
thentwocircuitsarecoupledmagneticallyandtheenergymaybetransferredfromonecircuit
totheanothercircuit.
Thisenergytransferisperformedbythetransferofthemagneticfieldwhichiscommonto
thebothcircuits.
Inelectricalengineering,twoconductorsarereferredtoasmutual-inductivelycoupledor
magneticallycoupledwhentheyareconfiguredsuchthatchangeincurrentflowthroughone
wireinducesavoltageacrosstheendoftheotherwirethroughelectromagneticinduction.
Theamountofinductivecouplingbetweentwoconductorsismeasuredbytheirmutual
inductance.
Figure4:InductiveCouplingwithFourComponentFluxes
Powertransferefficiencyofinductivecouplingcanbeincreasedbyincreasingthenumberof
turnsinthecoil,thestrengthofthecurrent,theareaofcross-sectionofthecoilandthe
strengthoftheradialmagneticfield.Magneticfieldsdecayquickly,makinginductive
couplingeffectiveataveryshortrange.
5.2InductiveCharging
Inductivechargingusestheelectromagneticfieldtotransferenergybetweentwoobjects.A
chargingstationsendsenergythroughinductivecouplingtoanelectricaldevice,whichstores
theenergyinthebatteries.Becausethereisasmallgapbetweenthetwocoils,inductive
chargingisonekindofshortdistancewirelessenergytransfer.

19. 10
Inductionchargerstypicallyuseaninductioncoiltocreateanalternatingelectromagnetic
fieldfromwithinachargingbasestation,andasecondinductioncoilintheportabledevice
takespowerfromtheelectromagneticfieldandconvertsitbackintoelectricalcurrentto
chargethebattery.Thetwoinductioncoilsinproximitycombinetoformanelectrical
transformer.Greaterdistancescanbeachievedwhentheinductivechargingsystemuses
resonantinductivecoupling.

20. 11
CHAPTER6INDUCTANCEOFCOILANDCOILDESIGN
6.1Introduction
Anidealinductorhasinductance,butnoresistanceorcapacitance,anddoesnotdissipateor
radiateenergy.However,realinductorshaveresistance(duetotheresistanceofthewireand
lossesincorematerial),andparasiticcapacitance(duetotheelectricfieldbetweentheturns
ofwirewhichareatslightlydifferentpotentials).Athighfrequenciesthecapacitancebegins
toaffecttheinductor'sbehavior;atsomefrequency,realinductorsbehaveasresonantcircuits,
becomingself-resonant.Atfrequenciesabovethisthecapacitivereactancebecomesthe
dominantpartoftheimpedance.Energyisdissipatedbytheresistanceofthewire,andbyany
lossesinthemagneticcoreduetohysteresis.Athighcurrents,ironcoreinductorsalsoshow
gradualdeparturefromidealbehaviorduetononlinearitycausedbymagneticsaturation.At
higherfrequencies,resistanceandresistivelossesininductorsgrowduetoskineffectinthe
inductor'swindingwires.Corelossesalsocontributetoinductorlossesathigherfrequencies.
6.2SingleLayerCoil
Figure5:SingleLayerCoil
Asinglelayercoil,asshowninfigure,hastwoadvantages.Firstly,likeallaircorecoils,itis
freefromironlossesandthenon-linearitymentionedabove.Secondly,singlelayercoilshave
theadditionaladvantageoflowself-capacitanceandthushighself-resonantfrequency.
Inthesimplecaseofasinglelayersolenoidalcoiltheinductancemaybecalculatedas
follows:

21. 12
WhereListheinductance,disthecoildiameterinmeters,listhecoillengthinmetersandn
isthenumberofturns.
6.3Lossesincoil:
Athighfrequencies,particularlyradiofrequencies(RF),inductorshavehigherresistanceand
otherlosses.Inadditiontocausingpowerloss,inresonantcircuitsthiscanreducetheQ
factorofthecircuit,broadeningthebandwidth.InRFinductors,whicharemostlyaircore
types,specializedconstructiontechniquesareusedtominimizetheselosses.Thelossesare
duetotheseeffects:
I.Skineffect:Theresistanceofawiretohighfrequencycurrentishigherthanitsresistance
todirectcurrentbecauseofskineffect.Radiofrequencyalternatingcurrentdoesnotpenetrate
farintothebodyofaconductorbuttravelsalongitssurface.Therefore,inasolidwire,most
ofthecrosssectionalareaofthewireisnotusedtoconductthecurrent,whichisinanarrow
annulusonthesurface.Thiseffectincreasestheresistanceofthewireinthecoil,whichmay
alreadyhavearelativelyhighresistanceduetoitslengthandsmalldiameter.
II.Parasiticcapacitance:Thecapacitancebetweenindividualwireturnsofthecoil,called
parasiticcapacitance,doesnotcauseenergylossesbutcanchangethebehaviorofthecoil.
Eachturnofthecoilisataslightlydifferentpotential,sotheelectricfieldbetween
neighboringturnsstoreschargeonthewire.Sothecoilactsasifithasacapacitorinparallel
withit.Atahighenoughfrequencythiscapacitancecanresonatewiththeinductanceofthe
coilformingatunedcircuit,causingthecoiltobecomeselfresonant.
6.4BlockDiagram
Figure6:BlockDiagram

22. 13
6.5CircuitDiagram
Figure7:CircuitDiagramOfTransmitter
Figure8:CircuitDiagramOfReceiver

23. 14
6.6Componentsusedintransmitter:
Table1:Componentsusedintransmitter
Component’sName Component’sValueOrCode
VoltageSource,Vdc 15V
Capacitor,C 10nF
Resistor,R1 39ohm,5watt
Resistor,R2 39ohm,5watt
Resistor,R3 39ohm,5watt
Resistor,R4 39ohm,5watt
Resistor,R5 5.6kohm
Resistor,R6 5.6kohm
Diode,D1 1N4148
Diode,D2 1N4148
MOSFET,Q1 IRF540
MOSFET,Q2 IRF540
RadioFrequencyChoke,L1 120µH
RadioFrequencyChoke,L2 120µH
Transmittercoil,L 8µH

24. 15
6.7Componentsusedinreceiver:
Table2:Componentsusedinreceiver
Component’sName Component’sValueorcode
Diode,D1 OA79
Diode,D2 OA79
Diode,D3 OA79
Diode,D4 OA79
Capacitor,C1 10Nf
Capacitor,C2 100µF
VoltageRegulatorIC ICLM7812
Receivercoil,L 8µH

25. 16
CHAPTER7TRANSMITTER
7.1Workingoftransmittercircuit:
ThetransmittermoduleofourprojectismadeupofaD.C.powersource,anoscillatorcircuit
(commonlyknownasaninverter)andatransmittercoil.
TheD.C.powersourceprovidesaconstantD.C.voltagetotheinputoftheoscillatorcircuit.
There,thisD.C.powerisconvertedtoahighfrequencyA.C.powerandissuppliedtothe
transmittercoil.Thetransmittercoil,energizedbythehighfrequencyA.C.current,produces
analternatingmagnetic
field.
Figure9:TRANSMITTER
7.2DCsupply:
TheD.C.PowerSourceconsistsofasimplestepdowntransformerandarectifiercircuit.The
transformerstepsdownthevoltagetoadesiredlevelandtherectifiercircuitconverttheA.C.
voltagetoD.C.
7.3Oscillatorcircuit:
TheprototypeoscillatorCircuitdesignedfortheprojectisamodifiedRoyeroscillator.This
oscillatorcircuitisincrediblysimpleyetaverypowerfuldesign.Veryhighoscillatingcurrent
canbeachievedwiththiscircuitdependingonthesemiconductorused.Herehighcurrentis
necessarytoincreasethestrengthofthemagneticfield.
7.4Workingofoscillatorcircuit:
ThecircuitconsistsofwithtwochokeslabeledL1andL2,twosemiconductors(Here
N-channelEnhancementpower-MOSFETS)labeledQ1andQ2,aresonatingcapacitor
labeledC2andaninductor(herethetransmittercoil)labeledL3.Cross-coupledfeedbackis
providedviathediodesD1andD2.R1,R3andR2,R4arethebiasingnetworkfor
MOSFETS.
Whenpowerisapplied,DCcurrentflowsthroughthetwosidesofthecoilandtothe
transistors’drain.Atthesametimethevoltageappearsonbothgatesandstartstoturnthe
transistorson.Onetransistorisinvariablyalittlefasterthantheotherandwillturnonmore.

26. 17
Thecurrentwouldcontinuetoincreaseuntilthecoil(transformer)saturates.Theresonating
capacitorCcausesthevoltageacrosstheprimarytofirstriseandthenfallinastandardsine
wavepattern.
AssumingthatQ1turnedonfirst,thevoltageatthedrainofQ1’swillbeclampedtonear
groundwhilethevoltageatQ2’sdrainrisestoapeakandthenfallsasthetankformedbythe
capacitorandthecoilprimaryoscillatorthroughonehalfcycle.Afterthat,D1willbeforward
biasbymorevoltagethanD2andhenceitwillturnonQ2andcyclerepeats.
Theoscillatorrunsatthefrequencydeterminedbytheinductanceofthecoil,thecapacitor
valueandtoalesserextent,theloadappliedtothesecondary(Sourcecoil).Theoperating
frequencyisthefamiliarformulaforresonance,
F=1/2×π×√(LC)
7.5Transmittercoil:
Forthisprojectthetransmittercoilwasconstructedwith92mmdiameter,17swgcopper
wireand7turns.
Fromtheequationofinductanceofasinglelayeraircorecoil,wegetinductanceL=8.1uH.

27. 18
CHAPTER8RECEIVER
8.1WorkingofReceiver:
Thereceivermoduleofourprojectismadeupofareceivercoil,arectifiercircuitanda
voltageregulatorIC.Andadditionalbuckconvertertogetmorecurrentbydecreasingoutput
voltageto5volt.
AnA.C.voltageisinducedinthereceivercoil.TherectifiercircuitconvertsittoD.C.andthe
voltageregulatorIChelpstomaintainaconstantlimitedvoltageattheload.
Thefollowingblockdiagramgivesageneralideaofthereceivermodule:
Figure10:BlockDiagramOfTheReceiverModule
8.2Receivercoil:
Receivercoilforourprojectisdesignedsameastransmittercoilwithsamevalue.
8.3Rectifier:
Adiodebridgeisanarrangementoffour(ormore)diodesinabridgecircuitconfiguration
thatprovidesthesamepolarityofoutputforeitherpolarityofinput.Whenusedinitsmost
commonapplication,forconversionofanalternatingcurrent(AC)inputintodirectcurrenta
(DC)output,itisknownasabridgerectifier.Theessentialfeatureofadiodebridgeisthat
thepolarityoftheoutputisthesameregardlessofthepolarityattheinput.
8.4Operationofbridgerectifier:
DuringthePositivehalfcycleoftheinputACwaveformdiodesD1andD3areforward
biasedandD2andD4arereversebiased.Whenthevoltage,morethanthethresholdlevelof
thediodesD1andD3,startsconducting–theloadcurrentstartsflowingthroughit.Duringthe
negativehalfcycleoftheinputACwaveform,thediodesD2andD4areforwardbiased,and
D1andD3arereversebiased.LoadcurrentstartsflowingthroughtheD2andD4diodes.
Furtherwecanusecapacitorfiltertoremoveripplespresentinoutputofbridgerectifier.
Aftercapacitorfilter,smoothDCvoltageispresentattheinputofvoltageregulator.

28. 19
8.5VoltageregulatorIC:
Avoltageregulatorisanelectricalregulatordesignedtoautomaticallymaintainaconstant
voltagelevel.Itmayuseanelectromechanicalmechanism,orelectroniccomponents.
Dependingonthedesign,itmaybeusedtoregulateoneormoreACorDCvoltages.Inthis
project,LM7812voltageregulatorICisusedsinceitallowednomorethan12vtotheoutput.
8.6Buckconverter:
Itistotallyoptionalpartinreceivercircuit.Itisusedheretoincreasecurrentatoutput.Buck
converterisDCtoDCconverterwhichstepdownthevoltageandaccordingtoit,itincrease
outputcurrent.Efficiencyofconverterishigh(nearabout98%)andhenceverysmallamountof
powerlossinthismodule.

29. 20
CHAPTER9PCBLAYOUT
9.1Transmitter:
Figure11:PCBLayoutOfTransmitter
9.2Receiver:
Figure12:PCBLayoutOfReceiver

30. 21
CHAPTER10WIRELESSPOWERTRANSMISSION
10.1NeedforWPT
Wirelesspowertransfer(WPT)isthetransmissionofelectricalenergyfromapowersource
toanelectricalload,suchasanelectricalpowergridoraconsumingdevice,withouttheuse
ofdiscreteman-madeconductors.
Wirelesstransmissionisusefultopowerelectricaldevicesincaseswhereinterconnecting
wiresareinconvenient,hazardous,orarenotpossible.
10.2DifferentmethodsforWPT
WirelesspowertechniquesfallintotwoCategories:
1.Non-RadiativeorNearFieldMethod
2.RadiativeorFarFieldMethod
10.3NearFieldMethod
Innon-radiativetechniques,poweristypicallytransferredbymagneticfieldsusingmagnetic
inductivecouplingbetweencoilsofwire.Applicationsofthistypeincludeelectrictoothbrush
chargers,RFIDtags,smartcards,andchargersforimplantablemedicaldeviceslikeartificial
cardiacpacemakers.
10.4ResonanceInductionandotherMethods
ResonantinductivecouplingorElectrodynamicinductionisthenearfieldwireless
transmissionofelectricalenergybetweentwomagneticallycoupledcoilsthatarepart
ofresonantcircuitstunedtoresonateatthesamefrequency.Thisprocessoccursina
resonanttransformer,anelectricalcomponentwhichconsistsoftwohighQcoils
woundonthesamecorewithcapacitorsconnectedacrossthewindingstomaketwo
coupledLCcircuits.
Resonanttransformersarewidelyusedinradiocircuitsasbandpassfilters,andinswitching
powersupplies.Resonantinductivecouplingisalsobeingusedinwirelesspowersystems.
WewilldiscussaboutResonanceindetailinfurtherChapters.

31. 22
10.5FarFieldMethods:
InRadiativeorfar-fieldtechniques,alsocalledpowerbeaming,poweristransferredby
beamsofelectromagneticradiation,likemicrowavesorlaserbeams.Thesetechniquescan
transportenergylongerdistancesbutmustbeaimedatthereceiver.Proposedapplicationsfor
thistypearesolarpowersatellites,andwirelesspowereddroneaircraft.
Wirelesspowerusesthesamefieldsandwavesaswirelesscommunicationdeviceslikeradio,
anotherfamiliartechnologythatinvolveselectricalenergytransmittedwithoutwiresby
electromagneticfields,usedincellphones,radioandtelevisionbroadcasting,andWi-Fi.
Farfieldmethodsachievelongerranges,oftenmultiplekilometerranges,wherethe
distanceismuchgreaterthanthediameterofthedevice(s).
10.6Microwave
Microwavesareaformofelectromagneticradiationwithwavelengthsrangingfromone
metertoonemillimeter;withfrequenciesbetween300MHz(100cm)and300GHz(0.1cm).
Powertransmissionviaradiowavescanbemademoredirectional,allowinglongerdistance
powerbeaming,withshorterwavelengthsofelectromagneticradiation,typicallyinthe
microwaverange.Arectennamaybeusedtoconvertthemicrowaveenergybackinto
electricity.Rectennaconversionefficienciesexceeding95%havebeenrealized.Power
beamingusingmicrowaveshasbeenproposedforthetransmissionofenergyfromorbiting
solarpowersatellitestoEarthandthebeamingofpowertospacecraftleavingorbithasbeen
considered.
Powerbeamingbymicrowaveshasthedifficultythat,formostspaceapplications,the
requiredaperturesizesareverylargeduetodiffractionlimitingantennadirectionality.
Powerbeamingbymicrowaveshasthedifficultythat,formostspaceapplications,the
requiredaperturesizesareverylargeduetodiffractionlimitingantennadirectionality.For
example,the1978NASAStudyofsolarpowersatellitesrequireda1-kmdiameter
transmittingantennaanda10kmdiameterreceivingrectennaforamicrowavebeamat2.45
GHz.Thesesizescanbesomewhatdecreasedbyusingshorterwavelengths,althoughshort
wavelengthsmayhavedifficultieswithatmosphericabsorptionandbeamblockagebyrainor
waterdroplets.
Wirelesshighpowertransmissionusingmicrowavesiswellproven.Experimentsinthetens
ofkilowattshavebeenperformedatGoldstoneinCaliforniain1975andmorerecently(1997)
atGrandBassinonReunionIsland.Thesemethodsachievedistancesontheorderof
kilometer.Underexperimentalconditions,microwaveconversionefficiencywasmeasuredto
bearound54%.

32. 23
10.7LasersandotherMethods
Inthecaseofelectromagneticradiationclosertothevisibleregionofthespectrum,power
canbetransmittedbyconvertingelectricityintoalaserbeamthatisthenpointedata
photovoltaiccell.Thismechanismisgenerallyknownas'powerbeaming'becausethepower
isbeamedatareceiverthatcanconvertittoelectricalenergy.Atthereceiver,special
photovoltaiclaserpowerconverterswhichareoptimizedformonochromaticlightconversion
areapplied.
Advantagescomparedtootherwirelessmethodsare:
Collimatedmonochromaticwavefrontpropagationallowsnarrowbeamcross-section
areafortransmissionoverlargedistances.
Compactsize:solidstatelasersfitintosmallproducts.
Noradio-frequencyinterferencetoexistingradiocommunicationsuchasWi-Fiandcell
phones.
Accesscontrol:onlyreceivershitbythelaserreceivepower.
Drawbacksinclude:
Laserradiationishazardous.Lowpowerlevelscanblindhumansandotheranimals.
Highpowerlevelscankillthroughlocalizedspotheating.
Conversionbetweenelectricityandlightislimited.Photovoltaiccellsachieve40%–50%
efficiency.(Notethattheconversionefficiencyoflaserlightintoelectricityismuch
higherthanthatofsunlightintoelectricityusingsolarcells).
Atmosphericabsorption,andabsorptionandscatteringbyclouds,fog,rain,etc.,causeup
to100%losses.
Requiresadirectlineofsightwiththetarget.
Laser'power-beaming'technologywasexploredinmilitaryweaponsandaerospace
applications.Also,itisappliedforpoweringofvariouskindsofsensorsinindustrial
environment.Lately,itisdevelopedforpoweringcommercialandconsumerelectronics.
Wirelessenergytransfersystemsusinglasersforconsumerspacehavetosatisfylasersafety
requirementsstandardizedunderIEC60825.

33. 24
10.8Comparison
Figure13:Comparison

34. 25
CHAPTER11MAGNETICRESONANCEINDUCTION
11.1ResonantInduction:
Resonantinductivecouplingorelectrodynamicinductionisthenearfieldwireless
transmissionofelectricalenergybetweentwomagneticallycoupledcoilsthatarepartof
resonantcircuitstunedtoresonateatthesamefrequency.Thisprocessoccursinaresonant
transformer,anelectricalcomponentwhichconsistsoftwohighQcoilswoundonthesame
corewithcapacitorsconnectedacrossthewindingstomaketwocoupledLCcircuits.
Resonanttransformersarewidelyusedinradiocircuitsasbandpassfilters,andinswitching
powersupplies.
Resonanttransferworksbymakingacoilringwithanoscillatingcurrent.Thisgeneratesan
oscillatingmagneticfield.Becausethecoilishighlyresonant,anyenergyplacedinthecoil
diesawayrelativelyslowlyoververymanycycles;butifasecondcoilisbroughtnearit,the
coilcanpickupmostoftheenergybeforeitislost,evenifitissomedistanceaway.The
fieldsusedarepredominantlynon-radiative,nearfields,asallhardwareiskeptwellwithin
the1/4wavelengthdistancetheyradiatelittleenergyfromthetransmittertoinfinity.
Non-resonantcoupledinductors,suchastypicaltransformers,workontheprincipleofa
primarycoilgeneratingamagneticfieldandasecondarycoilsubtendingasmuchaspossible
ofthatfieldsothatthepowerpassingthroughthesecondaryisascloseaspossibletothatof
theprimary.Thisrequirementthatthefieldbecoveredbythesecondaryresultsinveryshort
rangeandusuallyrequiresamagneticcore.Overgreaterdistancesthenon-resonantinduction
methodishighlyinefficientandwastesthevastmajorityoftheenergyinresistivelossesof
theprimarycoil.
Usingresonancecanhelpimproveefficiencydramatically.Ifresonantcouplingisused,each
coiliscapacitivelyloadedsoastoformatunedLCcircuit.Iftheprimaryandsecondarycoils
areresonantatacommonfrequency,itturnsoutthatsignificantpowermaybetransmitted
betweenthecoilsoverarangeofafewtimesthecoildiametersatreasonableefficiency.
OneoftheapplicationsoftheresonanttransformerisfortheCCFLinverter.Another
applicationoftheresonanttransformeristocouplebetweenstagesofasuperheterodyne
receiver.

35. 26
11.2TermsrelatedtoResonance:
11.2.1Couplingcoefficient:
kisthecouplingcoefficient,Le1andLe2istheLeakageinductance.
Thecouplingcoefficientisthefractionofthefluxoftheprimarythatcutsthesecondarycoil,
andisafunctionofthegeometryofthesystem.Thecouplingcoefficient,k,isbetween0and
1.
Systemsaresaidtobetightlycoupled,looselycoupled,criticallycoupledorovercoupled.
Tightcouplingiswhenthecouplingcoefficientisaround1aswithconventionaliron-core
transformers.Overcouplingiswhenthesecondarycoilissoclosethatittendstocollapsethe
primary'sfield,andcriticalcouplingiswhenthetransferinthepassbandisoptimal.Loose
couplingiswhenthecoilsaredistantfromeachother,sothatmostofthefluxmissesthe
secondary.InTeslacoilsaround0.2isused,andatgreaterdistances,forexamplefor
inductivewirelesspowertransmission,itmaybelowerthan0.01.
11.2.2Energytransferandefficiency:
Thegeneralprincipleisthatifagivenoscillatingamountofenergyisplacedintoaprimary
coilwhichiscapacitivelyloaded,thecoilwill'ring',andformanoscillatingmagneticfield.
Theenergywilltransferbackandforthbetweenthemagneticfieldintheinductorandthe
electricfieldacrossthecapacitorattheresonantfrequency.Thisoscillationwilldieawayata
ratedeterminedbythegain-bandwidth(Qfactor),mainlyduetoresistiveandradiativelosses.
However,providedthesecondarycoilcutsenoughofthefieldthatitabsorbsmoreenergy
thanislostineachcycleoftheprimary,thenmostoftheenergycanstillbetransferred.
TheprimarycoilformsaseriesRLCcircuit,andtheQfactorforsuchacoilis:
Q=(1/R)sqrt(L/C).
BecausetheQfactorcanbeveryhigh,(experimentallyaroundathousandhasbeen
demonstratedwithaircoredcoils)onlyasmallpercentageofthefieldhastobecoupledfrom
onecoiltotheothertoachievehighefficiency,eventhoughthefielddiesquicklywith
distancefromacoil,theprimaryandsecondarycanbeseveraldiametersapart.
Itcanbeshownthatafigureofmeritfortheefficiencyis:
U=k*sqrt(Q1*Q2)
WhereQ1andQ2aretheQfactorsofthesourceandreceivercoilsrespectively,andkisthe
couplingcoefficientdescribedabove.

36. 27
11.2.3Powertransfer:
BecausetheQcanbeveryhigh,evenwhenlowpowerisfedintothetransmittercoil,a
relativelyintensefieldbuildsupovermultiplecycles,whichincreasesthepowerthatcanbe
received—atresonancefarmorepowerisintheoscillatingfieldthanisbeingfedintothecoil,
andthereceivercoilreceivesapercentageofthat.
11.2.4Voltagegain:
Thevoltagegainofresonantlycoupledcoilsisdirectlyproportionaltothesquarerootofthe
ratioofsecondaryandprimaryinductances.
A=k*sqrt(L2/L1)
11.2.5Transmittercoilsandcircuitry:
Unlikethemultiple-layersecondaryofanon-resonanttransformer,coilsforthispurposeare
oftensinglelayersolenoids(tominimizeskineffectandgiveimprovedQ)inparallelwitha
suitablecapacitor,ortheymaybeothershapessuchaswavewoundlitzwire.Insulationis
eitherabsent,withspacers,orlowpermittivity,lowlossmaterialssuchassilktominimize
dielectriclosses.
Toprogressivelyfeedenergy/powerintotheprimarycoilwitheachcycle,differentcircuits
canbeused.OnecircuitemploysaColpittsoscillator.
11.3ImplementationofMRIinourproject:
InourprojectweusetheprincipleofInductionforthetransferofpowerfromtheprimaryto
thesecondarycoil.ByusingonlyInductiononecannotgetagoodstablepoweratthereceiver
endsoweusetheprincipleofResonantMagneticInduction.

37. 28
CHAPTER12WIRELESSPOWERTRANSMISSIONUSING
RESONANTINDUCTIVECOUPLING
12.1Introduction
Previousworkinthisfieldhasindicatedthatwirelesspowertransmissionbetweentwo
inductivelycoupledcoilshaspoorrangeandefficiency.Thisisstandardinductivecoupling
whichresultsinlowpowerefficiency(<30%)andlargecoilssincemostofthefluxisnot
linkedbetweenthecoils.Theresonanceofaninductivelycoupledsystemincreasesthe
amountofmagneticfluxlinkedbetweencoilsandimprovesthepowertransmission
significantly.Inthisproject,wewillintroducewirelesspowertransferusingresonant
inductivecouplingtoincreasepowertransferefficiencyanddensitywithsmallercoils.
Weusetwocoils,transmittingcoilandreceivingcoilthataretunedtoresonateataparticular
frequencysothatthepowertransmissionimprovessignificantly.Inthisprojectwehaveused
aRoyerOscillatorandavariablecapacitortotunethecircuit.
12.2BlockDiagram
Figure14:BlockDiagramOfWirelessPowerTransmissionUsingResonantInductive
Coupling

38. 29
12.3BasicComponents
12.3.1Step-downTransformer:
Supplyistakenfromanormal220V,50Hzsinglephasesocketandfedtothestepdown
transformer.Ithasacurrentratingof2A.Here,wehavesteppeddownthevoltagefrom220V
ACto12VAC.
12.3.2BridgeRectifier:
TheoutputfromthetransformerisrectifiedusingaBridgeRectifiermodule.Attheoutputwe
geta12VunregulatedDCoutput.
12.3.3VoltageRegulator:
WeneedtoobtainaconstantregulatedDCvoltagetosupplytheoscillatorcircuit.Hencewe
haveusedaBuckConvertermodule.ItisaDC-DCconverterwhichgivesaregulatedDC
supplyattheoutput.
12.3.4Oscillator:
Weneedtogetanoscillatingsignalatthetransmittingcoil.Henceweuseasuitableoscillator
circuittogetasinusoidaloutput.WehavechosenRoyerOscillatorcircuitinourproject.
12.3.5Transmission&ReceivingCoils:
Wehaveusedtwocoilswhichinductivelycoupledandtheirfluxislinkedwitheachother.
Thesebehavelikeanaircoretransformerforthetransmissionofpower.Wehavechosen
copperandaluminumcoilsofdifferentsizestofindtheoptimumdesignformaximumpower
transfer.
12.3.6OutputRectification:
Atthereceivingend,weagainuseaBridgeRectifiermoduletogetaDCoutputfrom
thereceivingcoil.ThisDCoutputisunregulated.WehenceuseaBuckConverterto
getaconstantrectifiedvoltage.ThisregulatedDCvoltageissuppliedtoanykindof
DCload.

39. 30
CHAPTER13OSCILLATORDESIGN
13.1Introduction
Anelectronicoscillatorisacircuitthatproducesaperiodic,oscillatingelectronicsignal,often
asinewaveorasquarewave.Oscillatorsconvertdirectcurrent(DC)fromapowersupplyto
analternatingcurrent(AC)signal.Theyarewidelyusedinmanyelectronicdevices.Common
examplesofsignalsgeneratedbyoscillatorsincludesignalsbroadcastbyradioandtelevision,
clocksignalsthatregulatecomputersandquartzclock,andthesoundsproducedbyelectronic
beepersandvideogames.
Oscillatorsareoftencharacterizedbythefrequencyoftheiroutputsignal:
Alowfrequencyoscillator(LFO)isanelectronicoscillatorthatgeneratesafrequency
below≈20Hz.Thistermistypicallyusedinthefieldofaudiosynthesizers,to
distinguishitfromanaudiofrequencyoscillator.
Anaudiooscillatorproducesfrequenciesintheaudiorange,about16Hzto20kHz.
AnRFoscillatorproducessignalsintheradiofrequency(RF)rangeofabout100kHzto
100GHz.
Inthisprojectwewillbeusingaclassofoscillatorknownasrelaxationoscillator.
13.2RelaxationOscillator
Anonlinearorrelaxationoscillatorproducesanon-sinusoidaloutput,suchasasquare,saw
toothortriangularwave.Itconsistsofanenergy-storingelement(capacitoror,morerarely,
aninductor)andanonlinearswitchingdevice(alatch,Schmitttrigger,ornegativeresistance
element)connectedinafeedbackloop.Theswitchingdeviceperiodicallychargesand
dischargestheenergystoredinthestorageelementthuscausingabruptchangesintheoutput
waveform.
Someofthemorecommonrelaxationoscillatorcircuitsarelistedbelow:
Pearson-Ansonoscillator
Ringoscillator
Delaylineoscillator
Royeroscillator
Multivibrator

40. 31
13.3RoyerOscillator
ARoyeroscillatorisanelectronicrelaxationoscillatorthatemploysasaturablecore
transformer.Itwasinventedandpatentedin1954byGeorgeH.Royer.Ithastheadvantages
ofsimplicity,lowcomponentcount,rectangularwaveforms,andeasytransformerisolation.
Bymakingmaximumuseofthetransformercore,italsominimizesthesizeandweightofthe
transformer.TheclassicRoyercircuitoutputssquare;amodifiedversion,essentiallyby
addingacapacitor,turnsitintoaharmonicoscillator,outputtingsinewaves.Bothversions
arewidelyused,mainlyaspowerinverters.
13.3.1CircuitDescription:
Thecircuitconsistsofasaturable-coretransformerwithacenter-tappedprimarywinding,a
feedbackwindingand(optionally)asecondarywinding.Thetwohalvesoftheprimaryare
drivenbytwotransistorsinpush-pullconfiguration.Thefeedbackwindingcouplesasmall
amountofthetransformerfluxbackintothetransistorsbasestoprovidepositivefeedback,
generatingoscillation.Theoscillationfrequencyisdeterminedbythemaximummagnetic
fluxdensity,thepowersupplyvoltage,andtheinductanceoftheprimarywinding.
Figure15:CircuitDescriptionOfRoyerOscillator

41. 32
13.4RoyerOscillatorinWPT
Magneticcouplingisattractivebecauseitallowsfairlylargeamountsofpowertobe
transmittedwithoutneedforhighvoltages.ThebasicideaisagaintohavetwohighQ
resonantcircuits,whicharenowcoupledmagneticallyandarepreferredtohaveaslow
characteristicimpedanceaspossible.
Thefirstmodificationtothecircuitwastoremovetheflybacktransformerandputanair
coredinductorinitsplace.Tominimizethecharacteristicimpedanceofthetankcircuit,we
firstusedasingleloopofcopperpipe.Tankcapacitorwassplitintomoreparallelcapacitors
oflowervalueforhighercurrentrating,andalsosplittheinductorintwogoingtodrainof
eachMOSFET,inordertoavoidtappingthecenterofthecopperloop.
13.4.1Design:
Figure16:DesignOfRoyerOscillator
Ourexperimentalrealizationoftheschemeconsistsoftwocoilstunedatthesamefrequency.
AnoscillationcircuitisconnectedwithasourcecoilSisinturncoupledresonantinductively
toaloadcarryingcoilQ.Thecoilsaremadeofanelectricallyconductingcopperwireofa
cross-sectionalradiuswoundintoaconcentriccoilofmultipleturn,radiusr.Thenaradio
frequencyoscillatingsignalispassedthroughthecoilS,itgeneratesanoscillatingmagnetic
fieldthroughtheinductanceofthecoilS,whichistunedatthesamefrequencybythe
inductanceofthecoilandaresonatingcapacitorc.TheloadcoilQ,tunedatthesame
resonantfrequencyreceivesthepowerthroughthemagneticfieldgeneratedbythesourcecoil
S.
Fortheoscillatorcircuitpresented,lowESRpolypropylenecapacitorsarehighly
recommendedtohandlethehighcurrentflowingthroughtheLCtank.Moreover,othertype
ofcapacitorcreateshighspikesinthesinusoidalwaveattheLCtankcircuitandaffectsthe
MOSFETs.However,Mylarcapacitorsatfirstwereusedwhichhaspolyesterasthedielectric.
Thecircuitbecameunstablebyusingthistypeofcapacitor.LaterMKPcapacitorswereused
whichperformedmuchbetter.Atfirst,thetransmittercircuitdidnotoscillate;insteadone
MOSFETandinductorheateduprapidly.Lateritwasfoundthat,shortcircuitwascausedby

42. 33
thevoltageofpowersupplyrisingtooslowlyonpower-up.Thiswassolvedbyusingaswitch
onthelowvoltagesidethatisimmediatelybetweentheoscillatorcircuitandtherectifier.
Aftertheoscillatorcircuitstartedtooscillateverylittlepowerwasavailableontheloadcoil.
Becausethereceivercoilwasslightlyoutofresonance,itcouldnotpickupthepower
properly.ThiswassolvedbybuildingbothLC-tankcircuitswithidenticalloopsand
capacitances,sothatboththecircuitshavethesameresonantfrequency.
Thefollowingtableshowsthecomponentswhichareusedtomaketheoscillator:-
Table3:Componentsareusedtomaketheoscillator
ComponentsName ComponentsValueorcode
VoltageSource,Vdc 15V
Capacitor,C1 100nF
Capacitor,C 60nF
Resistor,R1 100Ω
Resistor,R2 100Ω
Resistor,R3 10kΩ
Resistor,R4 10kΩ
Diode,D1 1N4142
Diode,D2 1N4142
MOSFET,Q1 1RF1010
MOSFET,Q2 1RF1010
RadioFrequencyChoke,L1 100
RadioFrequencyChoke,L2 100

43. 34
CHAPTER14ANTENNADESIGN
14.1Introduction
Anantenna(pluralantennaeorantennas),oraerial,isanelectricaldevicewhichconverts
electricpowerintoradiowaves,andviceversa.Itisusuallyusedwitharadiotransmitteror
radioreceiver.Intransmission,aradiotransmittersuppliesanelectriccurrentoscillatingat
radiofrequency(i.e.ahighfrequencyalternatingcurrent(AC))totheantenna'sterminals,and
theantennaradiatestheenergyfromthecurrentaselectromagneticwaves(radiowaves).In
reception,anantennainterceptssomeofthepowerofanelectromagneticwaveinorderto
produceatinyvoltageatitsterminals,whichisappliedtoareceivertobeamplified.Typically
anantennaconsistsofanarrangementofmetallicconductors(elements),electrically
connected(oftenthroughatransmissionline)tothereceiverortransmitter.Anoscillating
currentofelectronsforcedthroughtheantennabyatransmitterwillcreateoscillating
magneticfieldsaroundtheantennaelements,whilethechargeoftheelectronsalsocreatesan
oscillatingelectricfieldalongtheelements.Thesetime-varyingfieldsradiateawayfromthe
antennaintospaceasamovingtransverseelectromagneticfieldwave.Conversely,during
reception,theoscillatingelectricandmagneticfieldsofanincomingradiowaveexertforce
ontheelectronsintheantennaelements,causingthemtomovebackandforth,creating
oscillatingcurrentsintheantenna.
14.2ResonantAntenna
Themajorityofantennadesignsarebasedontheresonanceprinciple.Thisreliesonthe
behaviorofmovingelectrons,whichreflectoffsurfaceswherethedielectricconstantchanges,
inafashionsimilartothewaylightreflectswhenopticalpropertieschange.Inthesedesigns,
thereflectivesurfaceiscreatedbytheendofaconductor,normallyathinmetalwireorrod,
whichinthesimplestcasehasafeedpointatoneendwhereitisconnectedtoatransmission
line.Theconductor,orelement,isalignedwiththeelectricalfieldofthedesiredsignal,
normallymeaningitisperpendiculartothelinefromtheantennatothesource(orreceiverin
thecaseofabroadcastantenna).
14.2.1LoopAntenna:
Loopantennasconsistofalooporcoilofwire.Loopswithcircumferenceofawavelengthor
largeractsimilarlytodipoleantennas.Howeverloopssmallincomparisontoawavelength
actdifferently.Theyinteractwiththemagneticfieldoftheradiowaveinsteadoftheelectric
fieldasotherantennasdo,andsoarerelativelyinsensitivetonearbyelectricalnoise.However
theyhavelowradiationresistance,andsoareinefficientfortransmitting.Theyareusedas
receivingantennasatlowfrequencies,andalsoasdirectionfindingantennas.

44. 35
14.3DesignDetails
14.3.1FirstDesign:
Singleturncoil,18cmindiametermadeof6mmcoppertube.
Resistance:0.1Ω
Inductance:1µH
Qfactor:44.7
Resonantfrequency:520kHz
Maximumdistance:3cm
Figure17:CoilDesign1

45. 36
14.3.2SecondDesign:
75turncoil,16cmindiametermadeof0.51mmdiameteraluminumwire.
Resistance :5Ω
Inductance :400µH
Qfactor :17.88
Resonantfrequency:60kHz
Maximumdistance:7cm
Figure18:CoilDesign2

46. 37
14.3.3ThirdDesign:
25turncoil,16cmindiametermadeof1.15mmdiametercopperwire.
Resistance:0.3Ω
Inductance:42µH
Qfactor:96.6
Resonantfrequency:114kHz
Maximumdistance:40cm
Figure19:CoilDesign3

47. 38
14.4Comparisonofthedesigns
Table4:Comparisonofthedesigns
Design Description Resistance
Ω
Inductance
µH
Resonant
frequency
kHz
Distance
cm
Q
factor
1st Singleturncoil,
18cmindiameter
madeof6mm
coppertube.
0.1 1 520 3 44.7
2nd 75turncoil,16cm
indiametermade
of 0.51mm
diameter
aluminumwire.
5 400 60 7 17.88
3rd 25turncoil,16cm
indiametermade
of1.15mm
diametercopper
wire.
0.3 42 114 40 96.6

48. 39
CHAPTER15FINALASSEMBLY
15.1Introduction
Packagingisthetechnologyofenclosingorprotectingproductsfordistribution,storage,sale,
anduse.Packagingalsoreferstotheprocessofdesigning,evaluating,andproducingpackages.
Packagingcanbedescribedasacoordinatedsystemofpreparinggoodsfortransport,
warehousing,logistics,sale,andenduse.Packagingcontains,protects,preserves,transports,
informs,andsells.Inmanycountriesitisfullyintegratedintogovernment,businessand
institutional,industrial,andpersonaluse.
15.2Purposeofpackaging
Packagingandpackagelabelinghaveseveralobjectives
Physicalprotection–Theobjectsenclosedinthepackagemayrequireprotectionfrom,
amongotherthings,mechanicalshock,vibration,electrostaticdischarge,compression,
temperature,etc.
Barrierprotection–Abarriertooxygen,watervapor,dust,etc.,isoftenrequired.
Permeationisacriticalfactorindesign.Somepackagescontaindesiccantsoroxygen
absorberstohelpextendshelflife.Modifiedatmospheresorcontrolledatmospheresare
alsomaintainedinsomefoodpackages.Keepingthecontentsclean,fresh,sterileand
safeforthedurationoftheintendedshelflifeisaprimaryfunction.Abarrierisalso
implementedincaseswheresegregationoftwomaterialspriortoenduseisrequired,as
inthecaseofspecialpaints,glues,medicalfluids,etc.Attheconsumerend,the
packagingbarrierisbrokenormeasuredamountsofmaterialareremovedformixingand
subsequentenduse.
Convenience–Packagescanhavefeaturesthataddconvenienceindistribution,
handling,stacking,display,sale,opening,reclosing,using,dispensing,reusing,recycling,
andeaseofdisposal.

49. 40
15.3FinalPackaging
15.3.1HighFrequencyConvertor:
Figure20:HighFrequencyConverter1

50. 41
Figure21:HighFrequencyConverter2

51. 42
15.4HFConvertorClosed
Figure22:HFConverterClosed1

52. 43
Figure23:HFConverterClosed2

53. 44
15.5TransmissionandReceivingcoils
Figure24:TransmissionandReceivingcoils

54. 45
CHAPTER16RESULTS
16.1CROWaveforms
16.1.1NoloadInput
Figure25:CROWaveformsAtNoLoadInput

55. 46
16.1.2NoloadOutput
Figure26:CROWaveformsAtNoLoadOutput

56. 47
16.1.3LoadedOutput
Figure27:CROWaveformsAtNoLoadedOutput

57. 48
CHAPTER17CONCLUSION
Thegoalofthisprojectwastodesignandimplementawirelesspowertransfersystemvia
magneticresonantcoupling.Afteranalyzingthewholesystemsystematicallyforoptimization,
asystemwasdesignedandimplemented.Experimentalresultsshowedthatsignificant
improvementsintermsofpowertransferefficiencyhavebeenachieved.
Wehavedescribedanddemonstratedthatmagneticresonantcouplingcanbeusedtodeliver
powerwirelesslyfromasourcecoiltoaloadcoilwithanintermediatecoilplacedbetween
thesourceandloadcoilandwithcapacitorsatthecoilterminalsprovidingasamplemeanto
matchresonantfrequenciesforthecoils.Thismechanismisapotentiallyrobustmeansfor
deliveringwirelesspowertoareceiverfromasourcecoil.

58. 49
CHAPTER18POSSIBLEAPPLICATIONSANDFUTUREWORK
17.1Applications:
1)SmartPhones,PortableMediaPlayers,DigitalCamerasandTablets.
2)PublicAccessChargingTerminal.
1)ComputerSystems
2)Miscellaneous:Wirelesschargersarefindingitswayintoanythingwithabatteryinsideit.
ThisincludesgameandTVremotes,cordlesspowertools,cordlessvacuumcleaners,soap
dispensers,hearingaidsandevencardiacpacemakers.Wirelesschargersarealsocapableof
chargingsupercapacitors(supercaps),oranydevicethatistraditionallypoweredbya
low-voltagepowercable.
17.2Futurework:
Totransmitthepowertoagreaterdistance,ahighpowerradiofrequencyamplifierconnected
withanoscillatorisneeded.ButtheconstructionofthebulkyRFpoweramplifierrequires
muchtimeandpatience.
Highpowervacuumtubetransistoramplifierwithhighcurrentwillmakethesystemmore
efficient.
Acrystaloscillatorcircuitmightbeabetteroptionforthetransmittercircuitsinceitcan
produceaveryhighfrequencyA.C.current
.
Furthereffortonthissameprojectcanyieldsomerealsolutionsthatcansolvetheproblems
ofthisproject.Theknowledgeofthisprojectwillhelpthosewhowanttodesignawireless
chargingsystem.

59. 50
Figure28:POSSIBLEAPPLICATIONSANDFUTUREWORK

60. 51
CHAPTER18REFERENCES
https://en.wikipedia.org/wiki/Wireless_power_transfer
https://markobakula.wordpress.com
http://4hv.org/e107_plugins/forum/forum_viewtopic.php?74096
http://www.instructables.com/id/ZVS-Driver/
http://electronics.stackexchange.com/questions/175170/understanding/
http://www.smps.us/inverters.html
http://wiki.4hv.org/index.php/Royer_oscillator
https://www.wirelesspowerconsortium.com/
http://www.icnirp.org/en/frequencies/high-frequency/index.html
http://www.eurekalert.org/pub_releases/2014-04/tkai-wpt041714.php

61. 52
CHAPTER19BIOGRAPHY
1)JacobMillmanandChristosC.Halkias,―IntegratedElectronics:AnalogandDigital
CircuitsandSystems
2)MuhammadH.Rashid,―PowerElectronics:Circuits,Devices,andApplications
3)RobertL.BoylestadandLouisNashelsky,ElectronicDevicesandCircuitTheory
4)WilliamH.Hayt,Jr.andJohnA.Buck,EngineeringElectromagnetics

62. 53
APPENDIX
1)DatasheetofMOSFETIRF540.
2)DatasheetofOA79.
3)DatasheetofLM7812.