李坤英文翻译.docx

李坤英文翻译.docx

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李坤英文翻译

毕业设计（论文）

外文文献翻译

专业

新能源科学与工程

学生姓名

李坤

班级

能源111

学号

1110604120

指导教师

张胜超

电气工程学院

1、英文原文

SolarTrackingSystem:

MoreEfficientUseofSolarPanels

J.Rizk,Y.Chaiko

Abstract：

Thispapershowsthepotentialsystembenefitsofsimpletrackingsolarsystemusingasteppermotorandlightsensor.Thismethodisincreasingpowercollectionefficiencybydevelopingadevicethattracksthesuntokeepthepanelatarightangletoitsrays.Asolartrackingsystemisdesigned,implementedandexperimentallytested.Thedesigndetailsandtheexperimentalresultsareshown.

Keywords：

RenewableEnergy,PowerOptimization.

I.

INTRODUCTION

Extrectinguseableelectricityfromthesunwasmadepossiblebythediscoveryofthephotoelectricmechanismandsubsequentdevelopmentofthesolarcell–asemi-conductivematerialthatconvertsvisiblelightintoadirectcurrent.Byusingsolararrays,aseriesofsolarcellselectricallyconnected,aDCvoltageisgeneratedwhichcanbephysicallyusedonaload.Solararraysorpanelsarebeingusedincreasinglyasefficienciesreachhigherlevels,andareespeciallypopularinremoteareaswhereplacementofelectricitylinesisnoteconomicallyviable.Thisalternativepowersourceiscontinuouslyachievinggreaterpopularityespeciallysincetherealisationoffossilfuel’sshortcomings.Renewableenergyintheformofelectricityhasbeeninusetosomedegreeaslongas75or100yearsago.SourcessuchasSolar,Wind,HydroandGeo-thermalhaveallbeenutilisedwithvaryinglevelsofsuccess.Themostwidelyusedarehydroandwindpower,withsolarpowerbeingmoderatelyusedworldwide.Thiscanbeattributedtotherelativelyhighcostofsolarcellsandtheirlowconversionefficiency.Solarpowerisbeingheavilyresearched,andsolarenergycostshavenowreachedwithinafewcentsperkW/hofotherformsofelectricitygeneration,andwilldropfurtherwithnewtechnologiessuchastitanium-oxidecells.Withapeaklaboratoryefficiencyof32%andaverageefficiencyof15-20%,itisnecessarytorecoverasmuchenergyaspossiblefromasolarpowersystem.

Thisincludesreducinginverterlosses,storagelosses,andlightgatheringlosses.Lightgatheringisdependentontheangleofincidenceofthelightsourceprovidingpower（i.e.thesun）tothesolarcell’ssurface,andtheclosertoperpendicular,thegreaterthepower[1-7].Ifaflatsolarpanelismountedonlevelground,itisobviousthatoverthecourseofthedaythesunlightwillhaveanangleofincidencecloseto90°inthemorningandtheevening.Atsuchanangle,thelightgatheringabilityofthecellisessentiallyzero,resultinginnooutput.Asthedayprogressestomidday,theangleofincidenceapproaches0°,causingansteadyincreaseinpoweruntilatthepointwherethelightincidentonthepaneliscompletelyperpendicular,andmaximumpowerisachieved.

Asthedaycontinuestowarddusk,thereversehappens,andtheincreasinganglecausesthepowertodecreaseagaintowardminimumagain.

Fromthisbackground,weseetheneedtomaintainthemaximumpoweroutputfromthepanelbymaintaininganangleofincidenceascloseto0°aspossible.Bytiltingthesolarpaneltocontinuouslyfacethesun,thiscanbeachieved.ThisprocessofsensingandfollowingthepositionofthesunisknownasSolarTracking.Itwasresolvedthatreal-timetrackingwouldbenecessarytofollowthesuneffectively,sothatnoexternaldatawouldberequiredinoperation.

II.

THESENSINGELEMENTANDSGNALPROCESSING

Manydifferentmethodshavebeenproposedandusedtotrackthepositionofthesun.ThesimplestofallusesanLDR–aLightDependentResistortodetectlightintensitychangesonthesurfaceoftheresistor.Othermethods,suchasthatpublishedbyJeffDammin‘HomePower’[8],usetwophototransistorscoveredwithasmallplatetoactasashieldtosunlight,asshowninFig.1.

Fig.1Alternativesolartrackingmethod

Whenmorningarrives,thetrackerisinstateAfromthepreviousday.Theleftphototransistoristurnedon,causingasignaltoturnthemotorcontinuouslyuntiltheshadowfromtheplatereturnsthetrackertostateB.Asthedayslowlyprogresses,stateCisreachedshortly,turningontherightphototransistor.ThemotorturnsuntilstateBisreachedagain,andthecyclecontinuesuntiltheendoftheday,oruntiltheminimumdetectablelightlevelisreached.Theproblemwithadesignlikethisisthatphototransistorshaveanarrowrangeofsensitivity,oncetheyhavebeensetupinacircuitundersetbiasconditions.Itwasbecauseofthisfactthatsolarcellsthemselveswerechosentobethesensingdevices.Theyprovideanexcellentmechanisminlightintensitydetection–becausetheyaresensitivetovaryinglightandprovideanear-linearvoltagerangethatcanbeusedtoanadvantageindeterminingthepresentdeclinationorangletothesun.Asaresult,asimpletriangularset-upwasproposed,withthetwosolarcellsfacingoppositedirections,asshowninFig.2.

Initsrestposition,thesolarcellsbothreceiveanequalamountofsunlight,astheangleofincidence,althoughnot90°,isequalinbothcasesasseeninFig.3.

Fig.2Set-upofsolarreferencecellsFig.3Solarreferencecellsatrestposition

Fig.4Solarreferencecellsatasignificantangletothesun

ItcanbeseeninFig.4thatasthesunmovesinthesky,assumingthatthesolartrackerhasnotyetmoved,theangleofincidenceoflighttothereferencepanelswillcausemorelighttofallononecellthantheother.

Thiswillobviouslycauseavoltagedifference,wherethecellthatisfacingthesunwillhavehigherpotentialthantheother.Thisphenomenonwillresultinadetectablesignalateachcell,whichcanbeprocessedbyasuitablecircuit.

III.APROTOTYPESOLARTRACKER

ThefinalstageinvolvedcouplingthecircuitrytothemotorandmountingitontothebracketThefinalproductisseencompleteinFig.5.IthasaSolarex9Wsolararraymadeofpolycrystallinesiliconmountedontheflanges,whichwasborrowedfromthetechofficers.

Quitesimplyhavingtwotestsubjectscarriedouttesting.Thefirstscenarioinvolvedremovingthepanelfromthetrackerandlayingitinaflatorientation.Theoutputwasconnectedtoaloadthatwoulddissipate9Wthatwouldmatchthepanel’s

rating.9Wat12Vcorrespondstoacurrentof0.75A,sobyOhm’slaw;aload

resistancewascalculatedasbeing16Ω.A15Ω50Wresistorwastheclosestvaluefoundandwasconnectedtothepanel.Thetrackingdevicestillrequirespower,buta12Vbatterythatisconnectedinachargingarrangementwiththesolarpanelsuppliesit.Thevoltageacrossandcurrentthroughtheloadwasmonitoredusingtwoseparatemultimeters,andwasrecordedeveryhalf-houronacleardayintoanExcelspreadsheet.Thereadingsweretakenonaspanofdaysthatpossessedsimilarconditionsincludingnocloudcover.ThereadingsareshownbelowinagraphgeneratedbyExcelinFig.6.

Itispossibletocalculateapercentageincreaseandanaverageincreasebywritingtheappropriatecalculationsinexcel.Itwasfoundthatinthiscase,thefixedpanelprovidedanaverageof39%ofits9W,or3.51W,calculatedovera12-hourperiod.Bycontrast,thetrackedsolarpanelachievedanoverall71%output,or6.3Woverthesametimeframe.Attheearlierandlaterhours,thepowerincreaseoverthefixedpanelreachedupto400%.Thisamountstoanaverage30%increaseinpowersimplybymaintainingthesolarpanelasperpendicularaspossibletothesun.

Toensurethatpowerwasnotbeingwasted,thedeviceitselfwasalsomonitoredforcurrentdrawntopoweritself.Whenthedevicewasatrest,anammeterwasplacedinserieswiththebattery.Thetotalcurrentat12Vwasmeasuredasonly4mA,whichcorrespondedtoapowerdissipationof48mWundernoload.

Fig.5AprototypesolartrackerFig.6Experimentalresultsofpowerincreasefor

trackedpanel

IV.CONCLUSION

Asolartrackerisdesignedemployingthenewprincipleofusingsmallsolarcellstofunctionasself-adjustinglightsensors,providingavariableindicationoftheirrelativeangletothesunbydetectingtheirvoltageoutput.Byusingthismethod,thesolartrackerwassuccessfulinmaintainingasolararrayatasufficientlyperpendicularangletothesun.Thepowerincreasegainedoverafixedhorizontalarraywasinexcessof30%.

REFERENCES

[1]Fahrenburch,A.andBube,R.1983,Fundamentalsofsolarcells,AcademicPress,NewYork.

[2]Partain,L.D.1995,SollarCellsandtheirapplications,JohnWiley&Sons.NewYork.

[3]EWeise,RKlockner,RKniel,MaShengHong,QinJianPing,“RemotePowerSupplyUsingWindandSolarenergy–aSino-GermanTechnicalCooperationProject”,BeijingInternationalConferenceonWindEnergy,Beijing,1995

[4]WichertB,LawranceW,FrieseT,FirstExperienceswithaNovelPredictiveControlStrategyforPV-DieselHybridEnergySystems,Solar’99

[5]DuryeaS,SyedI,LawrenceW,AnAutomatedBatteryManagementSystemforPhotovoltaicSystems,InternationalJournalofRenewableEnergyEngineering,

Vol1,No2,Aug1999

[6]TwidellJ,WeirJ,RenewableEnergySystems,ChapmanandHall,1994

[7]CentreforResourcesandEnvironmentalStudies,ANU,SustainableEnergySystems–PathwaysforAustralianEnergyReforms,CambridgeUniversityPress,1994

[8]Damm,J.Issue#17,June/July1990.Anactivesolartrackingsystem,HomeBrewMagazine.

2、

对应的中文翻译

出处：

WorldAcademyofScience,EngineeringandTechnology,2008,41:

313-315

中文2847字

太阳能跟踪系统:

更有效率地运用的太阳能电池板

J.里兹克Y.查克

摘要：

本文展示了由使用步进电机和光传感器来简单跟踪太阳的内部系统。

通过改进跟踪系统，在跟中太阳光的过程中，使得太阳能电池板与太阳成一个直角。

该文章包含了太阳能跟踪系统的设计、实施和实验