科技英语英译汉.docx
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科技英语英译汉.docx
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科技英语英译汉
科技英语翻译(电子类)
电
磁
波
类
论
文
翻
译
姓名:
XXXXX
学号:
130810XXXX
学院:
理学院
专业:
电子信息科学与技术
任课教师:
XXXXXXX
1.2.1WirelessPowerTransmissionMechanisms
WPTisthetransmissionofelectricalenergyfromapowersourcetooneormoreloadswithoutdirectlyusingsolidwiresorconductors.Itcanbegenerallyclassifiedasradiativeornon-radiativebasedontheenergytransmissionmechanisms.
Intheradiativeorfar-fieldtechnology,alsocalledpowerbeaming,poweristransferredintheformofelectromagneticradiationlikemicrowavesorlaserbeams[5-9].Relyingonthehigh-frequencysignalemissionofapowersource,energycanbetransportedoverlongdistances,whichwouldbemuchgreaterthanthesizeofthetransmittingandreceivingdevicesliketheantenna.Duetotheomni-directionalpropagationofelectromagneticwavesintheair,thetransmittermustbeaimedatthereceivertoincreasetheenergytransmissionefficiency.Inaddition,thepotentialhealthrisksofhumanexposuretoelectric,magnetic,andelectromagneticfieldsintheopenenvironmentareassociatedwithallwirelesspowersystemsfromshortrangetolong-range,lowpowertohighpower,lowfrequency(kHz)tohighfrequency(GHz),whichlimitthenon-radiatedtechnologyaswell[10-14].
Thenon-radiativeornear-fieldtechnologycantransferpowerwithinshortrangecomparedtoitsradiativecounterpart.Itfurtherfallsintotwofurthercategories,capacitivecouplingandinductivecoupling.Inthecapacitivecouplingtechnology[15-20],poweristransmittedthroughtheelectricfieldbetweenapairofmetalplates,whichformacapacitor.Duetothelimitationsofthehazardousvoltagesimposedontheelectrodesrequiredtotransferacertainamountofpower,itshowsadvantagesonlyinlow-powersmall-air-gap(within1mm)applications,thoughthe
potentialsinkilowatt-levelapplicationshaverecentlybeenreportedin
[19-20].Incontrast,theinductivecouplingtechnology[21-22]makesuseofthemagneticfieldinducedbythealternatingcurrentsinapairofcoils,likeatransformer,whichissuitableforlowtohighpowerlevelsoveralongerenergytransmissiondistance(>1mm).Duetothefactthatthemagneticcouplingbetweentwoadjacentcoilsinaninductively-coupledWPTsystemisusuallyweak,itspowertransferefficiencywilldroptremendouslyastheair-gapbecomeslonger.
Inordertoincreasetheefficiencyofaninductively-coupledWPT,themagneticresonancetechnologyisused,wherepoweristransferredbythemagneticfieldbetweentworesonantcircuits,oneinthetransmittercoilandtheotherinthereceivercoil.Forexample,onecapacitorisconnectedinserieswiththetransmitterandanothercapacitorisconnectedinparallelwiththereceiver,whichareusedtocompensatetheleakageinductancealongeachpowerflowloopsoastotunethetwocircuitsatthesamedesiredresonantfrequency.Ithasbeenreportedin[23-24]thatusingmagneticresonancecaneffectivelyincreasethe
transmissionrangewhilemaintaininganacceptableefficiency.TherebythistechnologycontributestotherapiddevelopmentofWPTfrom
short-rangetomid-range[25-30]andisadoptedbymostinductiveWPTsystemsnowadays.Thediscussioninthefollowingchapterswillfocusontheinductively-coupledWPTemployingmagneticresonance.
1.2.2Applications
WPTisregardedasapreferablesolutionforcontactlesssupplyofpoweroveracertainair-gap.Duetoitsexclusiveadvantagesofsafety,flexibility,andconvenience,itfindsvariousapplicationsrangingfrommicrowattbiomedicalimplantabledevicestokilowattbatterychargingsystems.
A.Biomedicalimplants.
Biomedicalimplantabledevices,suchasglucosemonitoringimplants,
pacemakers,andcochlearimplantsasshowninFigure1.3,arewidelyusedtomonitordiseases,stimulatehumanorgans,anddelivermedicines.Howevertherisksofthebattery-replacingsurgerywhentheenergystoredisdepletedhasbecomeanissue.Whatismore,thebulkybatteryembeddedintheelectronicdeviceslimitstheminiaturizationoftheimplants,whichhascrucialsignificanceforeffectivenessandpatientsafety.Thetechnologyofwirelesspowering,ortranscutaneousenergytransmission,enablesconvenientwirelesscharging,andevenremovalofthebattery.TheuseofWPTthroughradio-frequencyelectromagneticwavesinbiomedicalapplicationshaskindledsincethe1970s[31-34].Nowadaysithasbeensuccessfullyimplementedinartificialhearts[35-37],cardiacpacemakers[38-40],cochlearimplants[41-42],andothergeneric
biomedicalimplantabledevices[43-45].Severalcontrolmethodshavebeen
reportedin[46-50]tofulfilltheoutputregulationpurposewhilemaintaininghighefficiencyagainstthecouplingandloadingchanges.
B.Consumerelectronics.
OnebigapplicationfieldofWPTliesinconsumerelectronicproducts,
amongwhichthemostsuccessfulcommercializationcaseisthewirelessbatterychargingtechnologyformobilephones[51-57].Theplanarwindingtopologywithachargingsurfaceisregardedasthemostsuitableforthelowpowermobileandwearabledevicechargingaswellasmanyotherconsumerelectronicdevicesofhigherpowerlevels.Despitethefeaturesofsafetyandconveniencecomparedwiththecord-basedchargingmethods,theadoptionofacommonwirelesschargingplatformforarangeofconsumerelectronicshasenvironmentalsignificanceinthatitcanreducethedumpingoftonsofwastedchargers.Figure1.4listssomewirelesschargingproductsavailableonthemarket.
C.Electricvehicles.
Thedevelopmentoftheelectricvehicle(EV)technologyisregardedasaneffectivewaytoreducethegreatdemandforfossilfueldemandandgreenhouseemissions.Despitetheenvironmentalbenefits,EVshavenotgotthebusinesssuccessinthemarketduetothebottleneckofthebatterytechnology.Theinsufficientenergydensity,lowlifetime,andhighcostofLithium-ionbatteries[58-59]whicharecurrentlyusedinmostEVsgreatlyconstraintheoverallperformanceofanEVandcanmakeitunattractivetoconsumers.Forexample,theenergydensityofthecommercializedLithium-ionbatteriesinEVsisonly90–100Wh/kg,whichissopoorcomparedwiththegasoline’s12000Wh/kg.Inaddition,theplug-inchargerhasdisadvantageslikeincreasedrisksinhostile
environments,andreducedreliabilityunderharshclimates,inparticularincoldsnowyzones.Thereforeitisessentialtofindaconvenient,safe,andreliablesolutiontochargeEVs.Inductive-coupledWPTisregardedasapreferredalternative[60-65].
WPTcangetridofthechargingcablesandconnectorsandcontactlesslychargeanEVwhenitisparkedoveraneffectivechargingarea,usingso-calledstationarycharging[66-74].Thetransmitteronthegroundandthereceiveronthevehicleshouldbeaccuratelyalignedtoensurecontinuouspowerflowathighefficiencyinspiteoftheloosecouplingbetweenthetransmittingpadandthereceivingpad.Severalnewstructuresofthechargingpadshavebeenproposedin[69-71,73-74]toenhancethemagneticcouplingandachievegoodtolerancetomisalignment.Investigationsonoptimalcompensationdesignandcontrolmethodshavebeenreportedin[66-68,72]tobuildanefficientwirelesschargingsystem.Figure1.5depictsaprototypicalstationarywirelesschargingsystemwherethebluecircleonthegroundisthetransmittingpad.
Dynamicwirelesscharging,whichmakesuseofelectrifiedroadways,canprovidecontinuouspowertransferwhentheEVismoving,andtherebyreducetheon-boardbatterycapacity[75-84].ThisonlinechargingtechnologycanmakeEVsmorecompetitiveovertraditionalinternalcombustionvehiclesandmorepopularinthemarket.Thedesignconcerningdifferentkindsofpowersupplyrailsalongtheroadbedandassociatedpickupcoilsonthechassisofthecarshasbeenwidelyinvestigated.Figure1.6demonstratestheconceptofadynamicwirelesschargingsystemwheremultiplelumpedcoilsalignedontheroadconstitutethechargingtrackandcanprovidepowersupplywhentheEVispassingoverthemonebyone.
ItisbelievedthattheoverallbatterycapacityofEVswillgrowconsiderablywhentheygetwidelyusedinthenearfuture.AtthattimethewirelessEVchargingsystemwillplayanimportantroleinsmartgridmanagement[85-87].ThebidirectionalWPTtechnology[88-93]canmakeeverysingleEVwhichisindirectlyconnectedtothegridtakepartinpowerflowmanagementinthegridlikeloadbalancingbyvalleyfilling.
D.Othermiscellaneousapplications.
Besidestheaforementioned,WPTcanbewidelyusedinother
applications.Itfindsapplicationsinfactoryautomation,forexampledecentralizedpowersupplyinamanufacturingfloor[94],andcontactlessenergytransmissionforservomotors[95].Aninnovativecompanyhasbeenfoundedtoprovidewirelesslightingsolutions[96].WPTisanefficientwaytoachieveunderwaterpowerdelivery[97-98]andcanbeadoptedinundergroundmining[99-100].Morepotentialapplicationsinchallengingenvironmentsaretobeexploited.
1.2.3SystemDesignConsiderations
ThereareseveralimportantfactorstoconsiderwhiledesigningaWPT
system.Fromthepreviousdiscussion,theconceptofmagneticresonancerequiresacapacitorconnectedwiththecoiltocompensateitsself-inductance,orleakageinductance.InFigure1.7fourbasiccompensationtopologiesarepresenteddependingonhowthecompensatecapacitorsareconnectedwiththecoils,whichareseries-series(SS),series-parallel(SP),parallel-series(PS),andparallel-parallel(PP),whereL1istheself-inductanceofthetransmitter,R1isthecoilresistanceofthetransmitter,L2istheself-inductanceofthereceiver,R2isthecoilresistanceofthere
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