英语翻译原文.docx

英语翻译原文.docx

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英语翻译原文

AStudyofEnergy-SavingACSpeed–GoverningSystemwithElectromagneticLoad

CHENZheng-shi,LIUJuanXXX

（MaomingCollege,Maoming525000,China）

Abstract:

　Anewkindofvariablefrequencyspeed-governingexperimentsystemwhichhasthestructureoftwoparallelinvertersatDCbusandoutputofinverterdrivingtwoseriesasynchronousmotorsatthesameshaftispresentedinthispaper.TheresultsoftheexperimentshowthatthiscreativeACvariablefrequencyspeed-governingexperiment

systemcan:

a）realizetheloadrelationshipofdirectelectromagnetictorquebetweenthemotorgroup;b）getthecontinuouscontrolprocesseasilyforthereactionloadandpotentialenergyloadduringfourquadrant;c）achievethetotalavailabilityoftheregeneratedenergyatanykindofload.Thesystem’spowerconsumptionmakesupunder30%ofactualloadpoweratanykindofload.

Keywords:

ACspeed-governing;electromagneticload;energysaving;differencefrequency

1DevelopmentofACspeed–governing

Foralongtime,becauseDCMotorSpeedsuperiorperformanceandcoveruptheshortcomingsofcomplexstructures,andotherwidelyusedinengineeringprocesses.DCmotorratedspeedinthefollowingrun-time,maintainingaconstantcurrentexcitation,armaturevoltagecanbeusedtochangethemethodofachievingaconstanttorquespeedintheratedspeedoverrunningandmaintainingthearmaturevoltageconstant,canbeusedtochangethemethodexcitationconstantpowertransferSpeed.Usedspeed,double-loopDCconvertercurrentsystemwillbeanexcellentstaticanddynamicgovernorcharacteristics.

Therefore,duringthe1980sbeforethetransmissionspeedinthefield,DCconverterhasbeenthedominantposition.Inrecentyears,therapiddevelopmentofscienceandtechnologytospeedthedevelopmentoftheexchangecreatedaveryfavorabletechnicalconditionsandmaterialbasis.ACMotorSpeedControlsystemnotonlytheperformancewiththeperformanceofDCMotors,andthecostandmaintenancecostslowerthantheDCmotorsystems,higherreliability.

（1）ModerntypesofACDriveSystem

ModerncommunicationsystemsfromACMotorSpeed,powerelectronicpowerconverters,controllersanddetectors,andotherfourmajorcomponents.Powerelectronicpowerconverters,controllers,powerconsumptionisconcentratedinonetest,knownasthefrequencyconverter（VVVFdevices）.ACMotordifferent,andmultiplytospeedtheexchangeofdifferentsystems.Sospeedofmoderncommunicationsystemscanbedividedintoasynchronousmotorspeedcontrolsystemandsynchronousmotorspeedregulationsystem.Atpresenttherearethreemorecommonprogramme,whichistheexchangeofasynchronousmotorspeedregulationsystem,SRMexchangesystemandspeedtheexchangeofpermanentmagnetsynchronousmotorspeedregulationsystem.Speedinthedesign,whichismoreappropriatetotheprogramme,whichrequiredfurtheranalysis.

Throughoutthedevelopmentofcommunicationtechnologiesspeed,wecanseethatmoderncommunicationtechnologiesspeedthedevelopmentoffuturetrendsanddevelopments.

1,intelligentcontrolsystemtospeedtheexchangeofimpactstudies.

2,speedcontrolsystemtoimprovetheefficiencyoftheexchangemethod.

3,thepressureFrequencyDeviceresearch.

4,systemreliabilitystudies.

（2）ACDriveSystemBenefits

Foralongtime,duetoDCconvertersystemperformanceisbetterthanACDriveSystem,DCconvertersystemhasbeeninareasdominatedbyspeed.However,theDCconvertersystemhasseveralshortcomingsbelow.

1,aDCmotordrag.DCMotorspronetofailure,maintenancedifficulties.

2,Useislimited.Inflammable,explosiveandapoorenvironmentwhereminingcannot.

3,theDCmotorofstructuralfactors,sothatsinglespeedandcapacityconstraints,resultinginDCconvertersystemdevelopmentwaslimited.

4,DCmotorprices,farhigherthanACmotors.

Withelectricity,electronictechnologydevelopment,especiallyinthedevelopmentofcontroltechnologyinrecentyears,exchangesspeedaccesstotheleapinthedevelopment.ACDriveSystembelowseveralmajoradvantages.

1,ACMotorparticularcageinductionmotorpricesmuchlowerthantheDCmotor.

2,ACMotordifficulttofailure,maintenanceissimple.

3,ACmotorthereisnorestrictionontheuseofoccasions.

4,ACmotorscanbemuchgreaterthanthecapacityofsingleDCmotor.

Let’sreviewforamomentsomeofthevarioustermsastheyareusedtodescribesolid-statefrequencycontrollers.Therearerigidtechnicaldefinitionsasgenerallyusdterminology.First,thetechnicaldefinitionsassuggestedbyorganizationssuchasIEC,NEMA,andIEEE（InstituteofElectronicsEngineers）:

（1）Converter:

anoperativeunitforpowerconversioncomprisingoneormorevalvedevices（powersemiconductors,forexample）.

（2）Self-commutatedconverter:

aconverterinwhichthecommutationvoltagesaresuppliedbycomponentswithintheconverters.

（3）Rectifier:

aconverterforconversionfromACtoDC.

（4）Inverter:

ainverterforconversionDCtoAC.

（5）IndirectACconverter:

aconvertercomprisingarectifierandaninverterwithaDClink.

Formoranther,anddefinition5coversthecompletesystem.However,generalusageintheUnitedStatesistocallit“inverter”:

PWMinverter,adjustablevoltageinverter,orcurrentsourceinverter.

PWMVersusAVIVersusCSI

Allthreeofthemostcommonlyusedadjustable-frequencycontrollersconsistofthreebasicsections.TheinputsectionconvertstheincomingACpowertoAC.Thecentersection,orDClinkorDCvoltage.TheoutputsectioninvertstheDCintoACofACofthedesiredfrequency.

Thedifferencesamongthesethreetypesofcontrollersarethemannerinwhichtheadjustablevoltageisobtained,andthetechniqueusedtocreatetheadjustablefrequency.

PWM

PulseWidthModulation（PWM）manytypesoftechnology,andisconstantlydeveloping.Canbasicallybedividedintofourcategories,namelywidthPWM,sinePWM,PWMflux-trackingmethodoftrackingPWMandcurrentlaw.PWMtechnologytoovercomethephasedapplicationoftheprincipleofalldefectssothatthemotorstatorexchangeshavebeenclosetosine-voltageandcurrent,improvingtheelectricalpowerfactorandthepoweroutput.MostmodernPWMcircuitgeneratedbyhighoutputHSOtheSCM（80,196）anddigitalsignalprocessors,softwareprogramminggeneratedbyPWM.Inrecentyears,newdigitalPWMgenerationchipsforHF4752,SLE4520,M18,andsoachievepractical,andhavepracticalapplications

Pulse-widthmodulation（PWM）utilizesdiodesintheinputstagetoprovideafixed-voltageDCbus.Theoutput,orinverterstage,createsaseriesofpulsesofconstantvoltagewiththepulsewidthsandquantitiesvaryingasrequiredbythedesiredbythedesignedoutputfrequencyandvoltage.Theoutputsectionsuppliesandcontrolsbothparameters,adjustablefrequencyandadjustablevoltage.

AVI

Adjustable-voltageinverters（AVI）usethyristorsinthestagetoobtainadjustablevoltageintheDClink.TheoutputstageswitchesthisDCvoltagewiththyristorsortransistorsorGTOstoobtainasquare-wavewhosewidthandtimingsequencecontrolisobtainedinthesecondstage.

CSI

Currentsourceinverters（CSIs）aresimilartoAVIs,exceptthatthecontrolisarrangedtoprovideaseriesofsquarewavesofcurrentoutput.

2　Thestructureandthefeatureofthesystem

　　　　Fig.1showstheprincipleandstructureofthisACexperimentsystem.TheworkprocessoftraditionalACspeed-governingisthatvariablevoltagefromfrequencyconverterdrivesaninductionmotorwhichmakesgeneratorsupplytosomeloadssuchasresistorandelectricheatingelement,andthenproducestheelectromagnetictorqueonthegeneratorasloadtorqueofmotor.Butthisloadtorqueisbalancedbyachievingthecurrentpowerfromfrequencyconverter.SothetraditionalACspeed-governingexperimentsystemisaprocessofenergyconsuming.

Fig.1　ACspeed-governingexperimentsystem

TheACspeed-governingexperimentsystem,whichisshowninFig.1,hasbeengreatlyimprovedatstructure.Normalmotor-generatorarechangedintotwomotorsatthesameshaftandthetwoinvertersareparallelatDCbus.Thentheoutputofvariablefrequencycurrentdrivesthetwomotorsseparately.Twoinverterscanbecontrolledbymeansofdifferencefrequency.Theadvantageofthisexperimentsystemisnotonlyinthechangeofstructure,butmoreimportantisthatthefunctionindex,controlfeaturearemuchmoreimproved,especiallyforitscharacteristicofeconomicalenergy.Ifthelossbeyondthemotorloadisnotconsidered,theexperimentresultsshowaprocessofregenerateenergybeingfeededbackandutilizedtotallyinfact.

3　Analysisofsystemprinciple

3.1　Formandfeatureofmotorload

TheworkingprincipleofthissystemisthatbothinductionmotorsfixedonsingleaxisaredrivenbyACdifferecefrequencyvoltagethataretheoutputsoftwoinvertersbymeansofsettingdifferencefrequency.Itcanbeprovedbytheanalysisoftorquefeatureandparameterexpressionthatthetorqueofmotorone（M1）producedbyhighfrequencyvoltageisbiggerthantorqueofmotor（M2）producedbylowfrequencyvoltage.SoM1worksatthestateofmotor（quadrantone）anditselectromagnetictorqueisasthemaintorquetodriveM2,whichworksatthestateofgenerator（quadranttwo）andoverstepsthesynchronousspeed（n>n02）.Itisobviouslythatifthesystemhasthepossibilitytorecoverregenerateenergy,M2willproducetheelectromagnetictorquewhichhastheoppositedirectiontoM1,andmakesmotor-generatorgroupgettheloadrelationshipofdirectelectromagnetictorque.Fig.2showseachmechanicalfeaturesoftwomotors