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外文翻译--现代变频器技术分析.doc

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外文翻译--现代变频器技术分析.doc

ModernfrequencychangertechnicalanalysisChengXiHeilongjianglongmaymininggroupco.,ltd.Thegeneralfrequencychangerbyitsmeritsandsoonintellectualization,digitization,networkreceivespeoplesfavormoreandmore,butalongwiththegeneralfrequencychangerapplicationscopesexpansion,exposessomequestions.Inviewofthesequestions,thisarticlecarriedonhasanalyzedandproposedthecountermeasure.First,overtonequestionandcountermeasure.Thegeneralfrequencychangersmaincircuitformgenerallybytherectificationpart,thecontravariantpartandthefilterpartiscomposed.Therectificationpartforthethreephasebridgetypeuncontrolledrectifier,theinvertorspartistheIGBTthreephasebridgetypeinvertors,andtheoutputisthePWMprofile.Becausethegeneralfrequencychangersrectificationpartusesthediodeuncontrolledbridgetypelevelingcircuit,themiddlefilterpartusesthebigelectriccapacitytotakethefilter,thereforerectifiersinputcurrentinfactiscapacitorschargingcurrent,assumesahighermoreandprecipitouspulsewave,itsharmoniccomponentisbig.Fortheharmoniccancellation,mayuse1,Increasesthefrequencychangerelectricpowersupplyinternalresistance.Usuallyinthesituation,powerequipmentsinternalresistancemayplaythecushionfrequencychangerconcurrentfilterelectriccapacitysreactivepowerrole.Thiskindofinternalresistanceistransformersshortcircuitimpedance.Whenpowersourcecapacityrelativefrequencychangercapacityhour,thentheinternalresistancevaluerelativelyisbigger,theharmoniccontentissmallerWhenthepowersourcecapacityrelativefrequencychangercapacityisbigger,thentheinternalresistancevaluerelativelyisbigger,theharmoniccontentisbigger.Thereforebestchoiceshortcircuitimpedancebigtransformer.2,Installsthereactor.Installsthereactorisactuallyincreasesthefrequencychangerelectricpowersupplysinternalresistancefromexterior.Installsthedirectcurrentreactorinfrequencychangersexchangesideinstallmentexchangereactororinfrequencychangersdirectcurrentside,alsoorinstalls,suppressestheharmoniccurrent.3,Transformerheterogeneitymovement.Thegeneralfrequencychangersrectificationpartissixpulsewaverectifiers,thereforeproducestheovertoneisbig.Ifusingtransformersheterogeneitymovement,causesphaseanglemutualdeviation30°likeY△,△△thecombinationtwotransformerconstitutiontobeequalto12pulsewaveeffects,thenmayreducetheloworderharmoniccurrent28,playstheharmonicsuppressionrole.4,Adjustsfrequencychangerscarrierratio.Solongascarriercomparedtoenoughbig,isinferiortheovertonetobepossibletosuppresseffectively,speciallythereferencewavepeaktopeakvalueandthecarrierpeaktopeakvaluearesmallerthan100,13followingoddnumberovertonesnolongerappear.5,Specialpurposefilter.Thespecialpurposefilteruseinexaminingthefrequencychangerharmoniccurrentthepeaktopeakvalueandthephase,andproducesonewiththeharmoniccurrentpeaktopeakvaluetobethesame,butthephasejustrightoppositeelectriccurrent,passesthroughinthefrequencychanger,absorptionharmoniccurrent.Second,matchingofloadquestionandcountermeasure.ProducesmachinerystorquecharacteristicstodivideintothreetypesroughlyPermanenttorqueloading,airblowerpumpclassloadandpermanentpowertermination.Inviewofthedifferentloadtype,shouldchoosethedifferenttypethefrequencychanger.1,Permanenttorqueloading.Thepermanenttorqueloadingisreferstotheloadmomenttohavenothingtodowiththerotationalspeed,underanyrotationalspeed,thetorquemaintainsconstant.Butthepermanenttorqueloadingdividesintothefrictionclassloadandthepotentialenergytypecapacitytwokinds.2,Airblowerpumpclassload.Theairblowerpumpclassloadispresentindustryfieldapplicationmostequipment,althoughthepumpandairblowerscharacteristicaremanyandvaried,butmainlybythecentrifugalpumpandthecentrifugalfanapplication,thegeneralfrequencychangersareprimarilymostinthiskindofloadapplication.Thiskindofloadisnothightofrequencychangersperformancerequirement,onlyrequeststheefficiencyandthereliability,thereforethechoicehastheU/fconstcontrolmodelfrequencychangerthen,likeMitsubishifrequencychangerFRF540Lseries.Airblowerloadinactualmovementprocess,becausetherotorinertiaisquitebig,thereforefrequencychangersrisetimeandthedecelerationtimeareaveryimportantquestion.Theairblowerloadssystemrotorinertiacomputationisveryimportant.Whenfrequencychangerconcretedesign,accordingtothecomputedresult,carriesonthesuitablerevision,whenthefrequencychangerstartsdoesnotoccurtheoverflowtripandthefrequencychangerdeceleratewhendoesnothaveintheovervoltagetripsituation,choiceshortesttime.Butthepumpclassloadintheactualmovementprocess,easytohavethebuzz,thebuildthepressureandthewaterhangstheeffect,thereforetimefrequencychangershaping,mustchooseissuitableforthepumpclassloadthefrequencychanger,andfrequencychangerinfunctionhypothesistimemustaimattheabovequestiontocarryonestablishesalone.3,Permanentpowertermination.Thepermanentpowerterminationreferstotheloadwhichthetorqueroughlyandtherotationalspeedisinreverseproportion,likecoiler,unwindingcoilerandsoon.Speakingofcertainspeedchangescope,whenactuatesthepermanentpowerterminationusingthefrequencychanger,usuallytheconsiderationselectsthepermanenttorquevelocitymodulationmethodbelowsomerotationalspeed,whenishigherthanthisrotationalspeedonlythenselectsthepermanentpowervelocitymodulationmethod.Usuallyiscalledthisrotationalspeedspotsthebasefrequency,butthispointcorrespondencesvoltageoutputstheratedvoltageforthefrequencychanger.Third,givesoffheatthequestionandthecountermeasure.Frequencychangersgivingoffheatisproducesbytheinternalloss.Carriesontheradiationtothefrequencychanger,usuallyuse1,Usestheventilatorradiation.Frequencychangersinternalinstallationventilatormaycarryofffrequencychangersboxbodyinteriorradiation,iftheventilatorcannotthenormalwork,immediatelystopthefrequencychangermovement.2,Reducesinstallstheambienttemperature.Generalfrequencychangersenvironmentoperatingtemperaturegeneralrequestin10℃to50℃,ifcantakethemeasuretoreducethefrequencychangeroperatingtemperatureasfaraspossible,thenfrequencychangersservicelifelengthens,theperformanceisalsoquitestable.MayadopttwomethodsregardingthisquestionFirst,constructstheindependentfrequencychangerlowpressure,theinteriorinstallstheairconditioning,maintainsthelowpressurethetemperaturein15℃to20℃betweenSecond,frequencychangersinstallmentspaceneedstosatisfythefrequencychangerinstructionforusetherequest.Theabovetalksaboutthefrequencychangergivesoffheatisreferstothefrequencychangerintheratedrangethenormaloperationloss.Whenthefrequencychangerhastheunusualmovementforexampleoverflow,whencrossespressure,thelosswhichoverloadandsoonproduces,mustavoidthiskindofphenomenonthroughthenormalshapingtheoccurrence.Regardingtheairblowerpumpclassload,takeMitsubishifrequencychangerFRF540astheexample,whenthefrequencychangerisoppositeinitsratedload120overloads,itsdurationis60seconds,anddoesnotallowwithin300secondstopresentthesecondoverload.Whenthefrequencychangerpresentstheoverload,becausethepowerunititwindsthroughtheexcesscurrentelevatestemperature,causesthefrequencychangeroverheated,bymustcauseitstemperaturedecreasetocausefrequencychangersoverheatedprotectionmovementassoonaspossibletoeliminate,thisundercookingisfrequencychangersoverloadcycle.Thedifferentfrequencychanger,itsoverloadmultiple,theoverloadtimeandtheoverloadcyclearenotsame,anditsoverloadmultipleisbigger,theoverloadtimeisshorter.Electricalmachinerywhichactuatesregardingthefrequencychanger,maydivideintotwokindsaccordingtoitsworkingconditionLongtermworkingsystemandredundantshorttimeworkingsystem.Thelongtermworkingsystemselectricalmachinerymayaccorditsnamebrandstipulationdatalongtermmovement.Inviewofthiskindofload,thefrequencychangermaycarryontheshapingaccordingtotheelectricalmachinerydataplatedata,likecontinuousrunningoilpump,ifitselectricalmachinerypoweristime22kW,maychoosetheFRF54022kfrequencychangerthen.Theredundantshorttimeworkingsystemelectricalmachinery,itscharacteristicistheduplicationandshorttime,namelyelectricalmachinerysoperatingtimeandtheidletimecarriesonalternately,moreoverisquiteshort,thetwosum,accordingtothecountrystipulatedthatdonotsurpassfor60seconds.Theredundantshorttimeworkingsystemelectricalmachinerypermitsitsoverload,andhascertainelevationoftemperature.Thistime,ifchoosesthefrequencychangeraccordingtotheelectricalmachinerydataplatedata,willcreatefrequencychangersdamageinevitably.Inviewofthiskindofload,thefrequencychangerinthereferenceelectricalmachinerydataplatedatassituationmustaccordingtotheelectricalmachineryloaddiagramandfrequencychangersoverloadmultiple,theoverloadtime,andtheoverloadcyclecomestheshaping.Ifisredundanttheshorttimemovementtheelevator,itselectricalmachinerypoweris18.5kW,maychoosetheFRA54022Kfrequencychanger.Throughhastheproblemtothegeneralfrequencychangermovementprocessintheanalysis,proposedsolvesthesequestionactualcountermeasure,alongwiththe

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