高速旋轉(zhuǎn)機(jī)械中英文對(duì)照外文翻譯文獻(xiàn)

外文資料翻譯中英文對(duì)照外文翻譯文獻(xiàn)(文檔含英文原文和中文翻譯)LowPowerMagneticBearingDesignForHighSpeedRotatingMachineryP.E.Allaire,E.H.Maslen,andR.R.Humphris,DepartmentofMechanicalandAerospaceEngineeringUniversityofVirginiaCharlottesville,VA22901C.K.SortoreAuraSystems,Inc.EISegundo,CA90245P.A.StuderMagneticConceptsSilverSprings,MD20901317SUMMARYAgneticsuspensiontechnologyhasadvancedtothepointofbeingabletoofferanumberofadvantagestoavarietyofapplicationsintherotatingmachineryandaerospacefields.Onestrongadvantageofmagneticbearingsoverconventionalbearingsisthedecreaseinpowerconsumption.Theuseofpermanentmagnets,alongwithelectromagnets,isoneappealingoptionwhichcanfurtherreducethepowerconsumptionofthebearing.Thedesignandconstructionofasetofpermanentmagnetbiased,activelycontrolledmagneticbearingsforaflexiblerotorispresented.Bothpermanentmagnetsandelectromagnetsareusedinaconfigurationwhicheffectivelyprovidesthenecessaryfluxesintheappropriateairgaps,whilesimultaneouslykeepingtheundesirabledestabilizingforcestoaminimum.Thedesignincludestworadialbearingsandathrustbearing.Thetheoreticaldevelopmentbehindthedesignisbrieflydiscussed.Experimentalperformanceresultsforasetofoperatingprototypebearingsispresented.Theresultsincludemeasurementsofloadcapacity,bearingstiffnessanddampingandthedynamicresponseoftherotor.Withfewexceptions,theexperimentalmeasurementsmatchedverywellwiththepredictedperformance.Thepowerconsumptionofthesebearingswasfoundtobesignificantlyreducedfromthatforacomparablesetofallelectromagneticbearing.INTRODUCTIONMagneticbearingshaveanumberofstrongadvantages.Onemostobviousadvantageistheirnon~ontacting,virtuallyfriction-freecharacteristics.Entirelubricationsystemsandtheneedformechanicaloilseals,whichaddtofrictionlossesandinstabilitiesassociatedwithcrosscoupledbearingcoefficients,canbeeliminatedbyusingthesetypesofbearings.Thelifeexpectancyofamagneticbearing,inmanycases,canbemuchhigherthanthatofconventionalbearing.Duetothenon~ontactingnatureofthebearings,mechanicalpartsdonotwearout.Thiscanobviouslyincreasesystemreliabilityanddecreasecostlyrepairsandnecessarymaintenancewhichinterruptprofitablemachineoperation.Ifdesignedproperly,amagneticbearingcanperformundermuchharsherconditionsandenvironmentsforextendedperiodsoftimewhichwouldnotbepossiblewithothertypesofbearings.Onefurtheradvantageofthefrictionlesscharacteristicofthesebearingsisthatofpowerloss.Thepowerconsumptionofaconventionalfluid-filmbearingisinmanycasesmuchmorethanforamagneticbearing.Powerlossreductionsofoneorderofmagnitudeormorecanbeexpectedwhenamachineisconvertedfromusingconventionalbearingstomagneticbearings.Avarietyofworkhasbeenaccomplishedonanumberofdifferentapplicationsandaspectsofmagneticbearings.Anextensiveamountofresearchhasbeenperformedbyanumberofuniversityandindustryresearchersonthedevelopmentofmagneticbearingsinan·industrialcannedmotorpump[1].AnumberofothersuccessfulindustrialapplicationsofmagneticbearingshasbeenreportedbyWeise[21.Burrowset.al.[3]presentsthedevelopmentandapplicationofamagneticbearingspecificallydesignedforthevibrationcontrolofaflexiblerotor.Keith,et.al.[4]successfullydevelopedaPC-baseddigitalcontrollerformagneticbearings.Continuingresearchisbeingperformedintheareasofdigitalandadaptivecontrolsformagneticbearings.Inresearchingtheuseofpermanentmagnetsincombinationwithelectromagnets,ofparticularinterestaretwopatentscreditedtoPhilipStuder[5,6].Thesepatentscontainanumberoffeatures,primarilydealingwithpermanentmagnets,whichhaveusefulapplicationtothebearingsdiscussedinthispaper.WilsonandStu~er[7]havealsoappliedthepermanentmagnetbiasconcepttoalinearmotionbearing.Ohkamiet.al.[8]haveperformedsomeinterestingcomparisonstudiesofmagneticbearingsofvariousconfigurationswhichusepermanentmagnets.AnotherpaperbyTsuchiyaet.al.[9]studiesandcommentsonthestabilityofahighspeedrotorwhichissuspendedinmagneticbearingsbiasedwithpermanentmagnets.Meeks[10]hasalsoperformedacomparisonofthevariousmagneticbearingdesignapproachesandconcludesthatthecombiningofactivelycontrolledelectromagnetswithpermanentmagnetsresultsinasuperiormagneticbearingintermsofsize,weightandpowerconsumption.Therareearthpermanentmagnetsoftoday,inparticularSm-CoandNd-Fe-Bomagnets,offerveryhighperformancecharacteristicsintermsofmagneticstrength,energyproductandthermalqualities.Themagnetdesignerisabletoconcentrateaverylargeamountofmagneticenergyinasmallpackage,makingmoreefficientuseofavailablespace.ThedesignconceptforthepermanentmagnetbiasedmagneticbearingdesigndiscussedinthispaperisavariationonresearchanddevelopmentreportedbyStuder[5,6].Thefollowingtwosectionsgiveabriefdescriptionofhowthebearingsconceptuallyoperate.RadialMagnetiCBearingDescriptionAdiagramofapermanentmagnetbiasedradialmagneticbearingisshowninFigure1.Thisbearingisdesignedtooperateatoneendoftherotorandcontrolradialforcesonly.Fouraxiallymagnetizedarcsegmentmagnetsarepositionedcircumferentiallyadjacenttothestator.Thebiasfluxgeneratedbythepermanentmagnetspassesdownthelaminatedstatorpoleleg,throughtheworkingairgap,axiallyalongtheshaft,thenreturnstothepermanentmagnetvia.aradialbiaspolepiece.Theactivecontrolfluxgeneratedbythecoilsalsopassesdownthestatorpolelegandthroughtheworkingairgap.Thereturnpathfortheactivefluxisthencircumferentiallyaroundthestator,asshowninFigure1.Thisdesignrequiresonlyfourpolesandfourcoils,unlikeanallelectromagneticdesignwhichgenerallyrequireseight.Inaddition,sincethecoilsforeachbearingaxisareconnectedinseries,thebearingcontrolsystemrequiresonlyfivecurrentamplifierchannels,whichishalfasmanyasrequiredoftheallelectromagneticbearing.CombinationRadial/ThrustMagneticBearingDescriptionAschematicofthisbearingdesign,revealingthevariousmagneticpaths,isshowninFigure2.Thisbearingcombinescontrolofbothradialandthrustforces.Theradialportionofthebearingisidenticaltothatwhichwasdescribedintheprevioussection.Thethrustcontrolhowever,isimplementedbyauniquemagneticfluxconfiguration.Thepermanentmagnetbiasfluxpassingalongtheshaftsplitsequallybetweenthetwothrustpolesbeforereturningtothepermanentmagnet.Asingleactivecoilproducesamagneticflux,intheshapeofatoroid,whichsymmetricallyaddsorsubtractstothebiasfluxintheworkingairgapsbetweenthethrustdiskandthrustpoles.DesignConceptThebearingsdesignedforthisprojectaredifferentfromallelectromagneticbearingdesignsinthattheyemploybothpermanentmagnetsandelectromagnets.Permanentmagnetsgeneratethebiasfluxintheworkingairgapsandelectromagnetsareusedtomodulatethisflux.Thepurposeofestablishingabiasfluxintheworkingairgapsistolinearizethegoverningforceequationofthemagneticactuator.Thebiasfluxisanominalfluxdensityaboutwhichthecontrolfluxisvaried.Ifabiasfluxofzeroisused,(onlyoneopposingactuatorisoperatedatatime,)thentheforcegeneratedbytheactuatorontherotorfollowsaquadraticforcelaw,i.e.,theforcewillbeproportionaltothesquareofthefluxdensityintheairgaps.Consequently,theforceslewratewillbezerowhentherotorisinthenominalbalancedpositionandthetransientresponsewillbeadverselyeffected.If,however,thebearingfluxesaremodulatedaboutanon-zerobiasflux,(withopposingactuatorssymmetricallyperturbed,)itiseasilyshownthattheforcebecomeslinearlyrelatedtothecontrolflux.Thefollowingsectiondemonstratesthisimportantrelation.ForceRelationshipsTheforcegeneratedinanairgapofareaAgandlengthgbyamagneticactuatorcanbeexpressedbythedirectrelationwhereBgisthefluxdensityintheairgapandJ.Loisthepermeabilityoffreespace.Ifonlyasingleaxisofthebearingisconsidered,thenthenetforceactingontheshaftwillbethedifferenceofthetwooppositeactingactuatorforces.Assumingtheareasofthetwoopposingairgapsarethesame,theforceactingontheshaftbythemagneticbearingcanbeexpressedasThefluxdensityintheairgapsisbeingsuppliedbytwosources,i.e.,thepermanentmagnetandthecoil.Inordertoproperlyprovidedifferentialcontrol,thefluxesinthetwogapsaresymmetricallyperturbedsothatthefluxinonegapisincreasedwhilethefluxintheoppositegapisdecreasedbythesameamount.ThisimpliesthatwhereBpmisthefluxdensitygeneratedby'thepermanentmagnetandBeisthefluxdensitygeneratedbythecoil.SubstitutingEqs.l3,4)intoEq.(2),expandingandsimplifying,theforceactingontheshaftcannowbeexpressedasByexpressingtheequationfortheforceontheshaftinthisform,itisinterestingtonotethattheforceisnotonlyproportionaltothebiaslevel,Bpm,butitisalsolinearizedwithrespecttothecontrolflux,Be..OpenLoopStiffnessandActuatorGainTheforcegeneratedbythebearinginthehorizontaldirection,Fx,canbeaccuratelyapproximatedbythetruncatedTaylorseriesexpansioninthefollowingway:Iftnemagneticcircuitisbalanced,thenthefirstterminEq.(6)isequaltozeroandwherexrepresentstherotordisplacementandierepresentsthecontrolcurrentintheelectromagneticcoil.TheparametersKxandKiaredefinedashequantityKxisreferredtoastheopenloopstiffnessandrepresentsthechangeinthehorizontalforceduetohorizontaldisplacement.Theopenloopstiffnessisalwaysnegativewhichimpliesthatthebearingisunstableintheopenloopcontrolconfiguration.Unlikeaactualspringwithapositivestiffness,apositivedispacementoftherotortowardthemagnetwillincreasetheattractiveforce.ThequantityKirepresentstheactuatorgainofthebearing.Itrepresentschangesinthehorizontalforceduetocontrolcurrent,ie.Equivalentexpressionsexistforthecomponentsoftheverticalforceexpression.Expressionsfortheopenloopstiffnessandtheactuatorgainaredeterminedbyperformingtheappropriatedifferentiationoftheforceexpression.TheseexpressionstakeontheformwhereLandHrepresentthelengthanddemagnetizationforce,respectively,ofthepermanentmagnetandNisthenumberofturnsintheelectromagneticcoil.ControlSystemDescriptionThecontrolelementsofthissystemarethosecomponentswhichdetectthemotionoftheshaft,determinetherequiredcontrolforceandgenerateacoilcurrentrequiredbythemagneticbearingtogeneratethisforce.Themagneticbearingsystemconsistsoffourdistinctcomponents:themagneticactuator,thedisplacementsensorsandassociatedconditioningcircuits,theanalogPIDcontrollerandthepoweramplifier.Theactualmagneticbearingmainlyconsistsoftheelectromagneticcoils,ironpolepieces,rotorandpermanentmagnets.Thesignalconditioningcomponentconsistsoftheeddycurrentinductiondisplacementsensors,signalamplificationandcoordinatetransformationcircuits.Theanalogcontrollerprimarilyconsistsofthreeseparatecomponents.Thecomponentstaketheformofproportional(P),integral(I)andderivative(D)compensationnetworks.Thesethreeparallelstagesareaddedtogetherthroughasummingamplifiertoproducetheoutputoftheanalogcontroller.Thelastcomponentinthecontrolloopisthepoweramplifier.Theamplifier,uponrequestofthecontroller,suppliestherequiredcurrenttomagneticcoilstoproducethenecessaryfluxesinthebearing.Thedynamicsofthebearing-rotorsystemcanbecombinedwiththeoperatingcharacteristicsofthecontrolelectronicstoformaclosed-loopcontrolsystem.ThiscontrolsystemisshowninasimplifiedblockdiagramforminFigure3.Thedisplacementsensorcharacteristics,analogcontrollerandamplifiermakeuptherelativelycomplextransferfunctionofthefeedbackcontroller,Gc(s).Thefeedbackcontrollerrelatestherotorpositiontotheactuatorcurrent.Theclosed-looptransferfunctionforthismagneticbearingsystem,asdeterminedfromthisblockdiagram,isgivenbywheremisthemassoftherotorsupportedbythebearing.PrototypeBearingConstructionThefour-poleradialbearingstators,asshowninthediagramsofFigures1and2,weredesignedtobeidenticalforbothbearings.Thestatorsandrotorswereconstructedof3%silicon-ironlaminationmaterialwhichhadathicknessof0.007inches.Eachlaminatedcomponentconsistsofapproximately100laminations.Thelaminationsweregluedtogetherusingatwopartactivator/resinadhesiveandtheshapewasmachinedbywireEDM(electricdischargemachining.)Thebearingstatorshaveanoutsidediameterofapproximately3.0inchesandanaxiallengthofapproximately0.7inches.Theoutsidediameterofthelaminatedrotorisapproximately1.5inches.Thethrustbearingcomponentsweremachinedfromsoftmagnetiron.Thehighenergypermanentmagnets,madeoutofageodymium-Iron-Boronalloy,haveamaximumenergyproductof30MG-Oe.Thebearingssupportashaftweighingapproximately3.7Ibm.LoadCapacityMeasurementsofthemaximumloadappliedtotheshaft,beforefallingoutofsupport,areplottedasafunctionofproportionalcontrollergain,Kp,inFigure4.Theforceinthistestwasappliedbyhangingweightsontheshaft.Apulleysystemwasconstructedinsuchawaythattheforcecouldbeappliedinthedesireddirection.Theforceintheplotsrepresentsforcesappliedalongthebearingaxes.Thevariationofthemaximumloadatlowerproportionalgainsisactuallyameasureofthestabilitythresholdofthesystem.ItisnotedinEq.t8)thattheopenloopstiffness,Kxisdefinedatanominaloperatingpoint,i.e.,rotorpositionandcontrolcurrentequaltozero.However,asthebearingisloadedwithastaticforce,thesteadystatecurrentbeginstoincrease.ItcanbeshownanalyticallythatKxisafunctionoftheoperatingpointofthecontrolcurrent.Thatis,asthecontrolcurrentcurrentincreases,Kxalsoincreases.IncreasingproportionalgainhastheeffectofcompensatingforthisincreaseinKxandconsequentlyincreasingthestabilityofthesystem.Themeasurementsmadeathigherproportionalgainsrepresentamoreaccuratemeasureoftheactualloadcapacityofthebearing.Enoughstabilityisprovidedsothatmagneticsaturationisreachedinthebearingpolestructures.ThemaximumpredictedloadsintheplotsofFigure4arecalculatedatthepointofmagneticsaturation.EquivalentBearingStiffnessandDampingMeasurementsoftheequivalentstiffnessofthebearingsareshowninFigure5.Thissimplemeasurementwasperformedbyapplyingaconstantforce,~F,andnotingthedisplacement,~x,oftheshaft(controllerintegratorsturnedoff.)ThestiffnessthenisgivensimplybyKeq=~F/~x.Alinearregressionwasperformedonthemeasureddata,whichresultedinverygoodcorrelation,ascanbeobservedintheplots.Itisnotedthattheproportionalgainhasadirecteffectonthestiffnessofthebearings,ashasbeenpreviouslydemonstratedbyHumphris,et.al.[11].Relativedampinginthebearingswasinvestigatedfromawhitenoisefrequencyresponseanalysisofthebearingandrotor.Theanalysiswasperformedbyinjectingnoise,composedofallfrequenciesofinterest,intooneaxisoftheturbine-endradialbearing,andperformingaFFT(FastFourierTransform)analysisonthevibrationresponseofthataxis.Thislinearfrequencyresponse,composedof100averages,isshowninFigure6.Thederivativecontrollergain,Krwasvariedthrougharangeofvaluesasnotedintheplot.Asexpected,thederivativegainhadadirecteffectonthedampinginthebearings[11].Thefirstlargespikerepresentsthefirsttwomodesofshaftvibration.Theyareveryclosetogetherinfrequencyandessentiallyindistinguishable.Thefrequencyofthesecondspikeisthethirdmodeofvibrationandthethirdsmallspikeatapproximately60,000cpmisthefourthmode.Itisnotedthatthevariationofthederivativegainstronglyeffectsthefirsttwomodes,hasasmalleffectonthethirdmodeandvirtuallynoinfluenceonthevibrationamplitudeofthefourthmode.CriticalSpeedsandRotorResponseThedampedsynchronouscriticalspeedsoftheflexibleshaftsupportedbythesebearingscanbeapproximatelydeterminedfromthewhitenoisefrequencyresponseplotsofFigure6.Thesevalues,however,representthezerospeednaturalfrequencies,andthegyroscopicstiffeningeffectsofanyattacheddiskswouldnotbeincluded.Sincethenaturalfrequencyisgivenby,wherekistheshaftstiffnessandminthemodalmassoftherotor,itisofcourseexpectedthattheobservedcriticalspeeds,whentheshaftwasspinning,wouldbehigher.PlotsshowingthevibrationmagnitudeandphasefortheshaftspeedsthatwereobtainedisincludedinFigure7.Amplitudeinformationwastakendirectlyfromthemagneticbearingsensorsandakey-phasesensorwasusedtoprovidethephaseinformation.AccordingtothemaximumvibrationamplitudesobservedinFigure7,thefirstvibrationmodeisobservedtooccuratapproximately10,000rpmandthesecondatapproximately13,000rpm.PowerConsumptionFinally,anumberofpowerconsumptionmeasurementsweremade.Measurementsofthepowerweretakenwithawattmeterforanumberofcases.Thismeterisusedwiththeassumptionthatthemeasuredvoltageandcurrentbeingsuppliedtothecontrolelectronicsissinusoidalinnature.Inaddition,itisrealizedthatitrepresentsasomewhatgrossmeasurementasitincludesalltheinefficienciesofthevariouselectroniccomponents.Table1summarizestheresults.Thenon~ssentialelectronicdiagnosticcomponentsofthebearingsystemwereobservedtoconsumeonlyabout7watts.Thesemeasurementsrepresentasignificantimprovementoverthe500wattsofapproximatetotalpowerconsumedbyacomparablecurrentbiasedallelectromagneticbearingdesign.CONCLUSIONSThebrieftheorywhichwaspresentedinthispaperestablishedthebasicelectromagneticandmechanicalrelationshipsnecessarytodevelopasetofpermanentmagnetbiasedmagneticbearings.Thedesigninvolvedbothradialandthrustbearings.Theavailabilityofnewerrare-earthhighenergypermanentmagnetsmadeitpossibletoeffectivelyprovidethenecessarybiasfluxesinthebearing.Thebearingsandrotorweresuccessfullyconstructedandoperated.Anumberoftestsandexperimentswereperformedonthebearing-rotorsystem.Thetestsconsistedofloadcapacity,stiffnessanddampingmeasurements.Theresultsprovedtobeverypositiveinthatthetheoreticalpredictionsandtheobservedperformancematchedreasonablywell,givingcredibilitytothemodelswhichwereusedtoperformtheanalysis.Ofparticularinterestforthisstudywasthemeasuredpowerconsumptionofthebearings.Itclearlydemonstratesthattheuseofpermanentmagnetscanimprovetheoperatingefficiencyofanactivemagneticbearing.Itwassuccessfullyobservedanddemonstratedthatthesebearingshavestrongpotentialforfutureuseasefficient,reliablebearings.However,furtherresearchanddevelopmentisrequiredintheareasofcontrols,magneticmaterialsandactuatordesignbeforeitispossibletoinstallthemintoausefulindustrialapplication.REFERENCES1.AllaireP.;Imlach,J.;McDonald,J.;Humphris,R.;Lewis,D.;Banerjee,B.;Blair,B.;Clayton,J.;Flack,R.:"Design,ConstructionandTestofMagneticBearingsinanIndustrialCannedMotorPump,"PumpUsersSymposium,TexasA&M,Houston,TX,May1989.2.Weise,D.A.:"PresentIndustrialApplicationsofActiveMagneticBearings,"Presentedatthe22ndIntersocietyEnergyConversionEngineeringConference,Philadelphia,Pennsylvania,August1987.3.Burrows,C.R.,Sahinkaya,N.;Traxler,A.;andSchweitzer,G.:"DesignandApplicationofaMagneticBearingforVibrationControlandStabilizationofaFlexibleRotor,"ProceedingsoftheFirstInternationalMagneticBearingsSymposium,ETHZurich,Switzerland,June1988.4.KeithF.J.,Williams,R.D.;Allaire,P.E.;andSchafer,R.M.:"DigitalControlofMagneticBearingsSupportingaMultimassFlexibleRotor,"PresentedattheMagneticSuspensionTechnologyWorkshop,Hampton,Virginia,February1988.5.Studer.P.A.:NASA,MagneticBearing,Patent3865442,PatentApplication100637,February1975.6.Studer,P.A.:NASA,LinearMagneticBearing,Patent4387935,PatentApplication214361,December1980.7.Wilson,M.;andStuder,P.A.:"LinearMagneticBearings,"PresentedattheInternationalWorkshoponRareEarth-CobaltMagnetsandTheirApplications,Roanoake,Virginia,June1981.8.Ohkami,Y.,Okamato,0.;Kida,T.;Murakami,C.;Nakajima,A.;Hagihara,S.;andYabuuchi,K.:"AComparisonStudyofVariousTypesofMagneticBearingsUtilizingPermanentMagnets,"PresentedattheInternationalWorkshoponRareEarth-CobaltPermanentMagnetsandTheirApplications,Roanoake,Virginia,June1981.9.Tsuchiya,K;Inoue,M.;Nakajima,A.;Ohkami,Y.;andMurakami,C.:"OnStabilityofMagneticallySuspendedRotoratHighRotationalSpeed,."PresentedattheAerospaceSciencesMeeting,Reno,Nevada,January1989.10.Meeks,C.:"TrendsinMagneticBearingDesign,"PaperpresentedatNavalSeaSystemsCommandMagneticBearingForum,Washington,D.C.,July1989.高速旋轉(zhuǎn)機(jī)械的低功率磁力軸承設(shè)計(jì)總結(jié):磁懸液研究具有先進(jìn)的研發(fā)技術(shù)，有一定的優(yōu)勢(shì)，廣泛應(yīng)用于旋轉(zhuǎn)機(jī)械和航空航天等領(lǐng)域。最突出的優(yōu)勢(shì)，磁力軸承比傳統(tǒng)的軸承功耗少。電磁鐵是一個(gè)十分具有吸引力的選擇，它可以進(jìn)一步降低軸承的功耗。一組永久磁鐵偏置，主動(dòng)控制的磁軸承的柔性轉(zhuǎn)子。永久磁鐵和電磁鐵的配置有效地提供通量在合適的氣隙，同時(shí)將不穩(wěn)定力量降到最低。該設(shè)計(jì)包括2個(gè)徑向軸承和一個(gè)推力軸承。對(duì)設(shè)計(jì)理論和發(fā)展進(jìn)行了簡(jiǎn)要討論。一組操作的原型軸承的實(shí)驗(yàn)性能結(jié)果如下，結(jié)果包括負(fù)載能力的測(cè)量，軸承剛度和阻尼和轉(zhuǎn)子的動(dòng)態(tài)響應(yīng)。有幾個(gè)情況是例外，實(shí)驗(yàn)測(cè)量相匹配的預(yù)測(cè)性能非常好，這些軸承的功率消耗顯減少。簡(jiǎn)介:磁力軸承有許多優(yōu)點(diǎn)。一個(gè)最明顯的優(yōu)勢(shì)是無(wú)摩擦的特點(diǎn)。整個(gè)潤(rùn)滑系統(tǒng)和機(jī)械油封，這增加了摩擦損失和不穩(wěn)定性與交叉耦合軸承系數(shù)，可以消除這些類型的軸承的摩擦。一個(gè)磁力軸承的壽命，在正常情況下，可以遠(yuǎn)高于傳統(tǒng)的軸承。由于好性質(zhì)的軸承，機(jī)械零件不磨損。這可以明顯提高系統(tǒng)的可靠性，降低成本的維修，中斷盈利機(jī)器操作。如果設(shè)計(jì)得當(dāng)，磁軸承工作的時(shí)間是不可能與其他類型的軸承長(zhǎng)時(shí)間在嚴(yán)酷的條件和環(huán)境下進(jìn)行。對(duì)于這些軸承的摩擦特性，另一個(gè)優(yōu)點(diǎn)是功率損失。傳統(tǒng)的流體膜軸承的功率消耗無(wú)時(shí)無(wú)刻，遠(yuǎn)遠(yuǎn)超過(guò)了磁性軸承。當(dāng)一臺(tái)機(jī)器使用傳統(tǒng)的軸承到換用磁力軸承的時(shí)候，可以從一個(gè)數(shù)量級(jí)或更高的減少功率損耗。各種各樣的程序完成了一些不同的工作和磁性軸承的運(yùn)行。許多研究人員和工業(yè)研究人員已經(jīng)進(jìn)行了大量的實(shí)驗(yàn)研究，工業(yè)屏蔽電機(jī)泵的磁軸承的發(fā)展[1],和多磁軸承在工業(yè)廣泛應(yīng)用已被魏澤[2]報(bào)道。為撓性轉(zhuǎn)子振動(dòng)控制系統(tǒng)的開(kāi)發(fā)與應(yīng)[4]，成功研制出一種基于微機(jī)的磁力軸承數(shù)字控制器。正在進(jìn)行的數(shù)字和自適應(yīng)控制的磁軸承的持續(xù)研究，在研究永磁體結(jié)合電磁鐵的使用，兩個(gè)專利歸功于菲利普[5，6]。這些專利包含了一些內(nèi)容，主要是處理永久磁鐵，這有助于本文討論的軸承。Wilson和斯圖~二[7]也應(yīng)用了永磁偏置的概念，在一個(gè)直線運(yùn)動(dòng)軸承。ohkami等人[8]對(duì)使用永久磁鐵的各種結(jié)構(gòu)的磁力軸承進(jìn)行了一些有意義的比較研究。土屋等人的另一篇論文，[9]懸浮于永磁體的磁懸浮轉(zhuǎn)子高速轉(zhuǎn)子穩(wěn)定性的研究與評(píng)價(jià)。米克斯[10]還說(shuō)出各種磁軸承的設(shè)計(jì)方法并進(jìn)行比較和總結(jié)，控制電磁鐵與磁軸承的永久磁鐵的作用相結(jié)合，重量和功耗減少，今天的稀土永磁體，特別是釹鐵磁體，擁有非常高的性能特點(diǎn)，在磁場(chǎng)強(qiáng)度，能源產(chǎn)品和熱質(zhì)量方面。磁鐵設(shè)計(jì)人員能夠?qū)⒋罅康拇拍芰考性谝粋€(gè)小的包中，使得更有效地利用可用空間。對(duì)永磁偏置磁軸承的設(shè)計(jì)本文設(shè)計(jì)的概念是由Studer[5報(bào)告的研究和發(fā)展變化，6]。下面兩節(jié)簡(jiǎn)要說(shuō)明如何在概念上操作的軸承。1.組合徑向/推力磁軸承描述此軸承設(shè)計(jì)，揭示了各種磁性路徑，這種軸承的徑向和推力相結(jié)合的控制。軸承的徑向部分是相同的，這是在上一節(jié)中描述的。然而，推力控制，實(shí)現(xiàn)由一個(gè)獨(dú)特的磁通配置。永久磁鐵的偏置磁通通過(guò)沿軸分裂之前，兩個(gè)推力桿，返回到永久磁鐵。一個(gè)積極的線圈產(chǎn)生磁場(chǎng)，在一個(gè)環(huán)形的形狀，對(duì)稱添加或減去在推力盤(pán)與推力桿之間的工作氣隙磁偏置。2.設(shè)計(jì)理念本課題設(shè)計(jì)的軸承是不同于所有電磁軸承的設(shè)計(jì)中，他們采用永久磁鐵和電磁鐵。永久磁鐵產(chǎn)生的偏置磁場(chǎng)在工作間隙和電磁鐵是用來(lái)調(diào)節(jié)這個(gè)流量。在工作間隙建立偏置磁場(chǎng)的目的是對(duì)磁驅(qū)動(dòng)器的控制力方程線性化。偏置磁通是一個(gè)額定磁通密度的控制磁通變化的。如果零的偏置磁通，（只有一個(gè)相對(duì)的致動(dòng)器操作的時(shí)間，），然后由致動(dòng)器所產(chǎn)生的致動(dòng)器的轉(zhuǎn)子上的二次力法，即，該力將在空氣間隙中的磁通密度的平方成正比。因此，強(qiáng)制轉(zhuǎn)換率將是零，當(dāng)轉(zhuǎn)子處于額定平衡位置和瞬態(tài)響應(yīng)將受到不利影響。如果，軸承磁通調(diào)制約一個(gè)非零的偏置磁通，（與相對(duì)的致動(dòng)器對(duì)稱擾動(dòng)），很容易地表明，力與控制磁通呈線性關(guān)系。下面的部分演示了這個(gè)重要關(guān)系。力量關(guān)系磁性致動(dòng)器產(chǎn)生的空氣間隙中的空氣間隙的力可以表示由直接關(guān)系BG在空氣間隙和J.Lo的磁通密度是具有自由空間的通透性。如果僅僅是一個(gè)軸的軸承被認(rèn)為具有這種特性，由于軸上的凈力作用，兩個(gè)相反的作用致動(dòng)器力的差異。假設(shè)兩者的相對(duì)空氣間隙的區(qū)域是相同的，通過(guò)磁力軸承作用于軸上的力可以表示為F?？諝忾g隙中的磁通密度由2個(gè)源提供，即永磁體和線圈。為了正確地提供差分控制，在2個(gè)間隙的磁通對(duì)稱擾動(dòng)，一個(gè)間隙中的磁通增加，而相反的間隙中的磁通減少相同的量。這意味著B(niǎo)PM產(chǎn)生的永久磁鐵的磁通密度和由線圈產(chǎn)生的磁通密度。替代式。L3、4）代入式（2），擴(kuò)展和簡(jiǎn)化，作用在軸可以表示為Y表示對(duì)這種形式的軸力的方程，需要注意的是，力不僅是偏置電平，BPM比例很有趣，但它也是線性化控制流量。開(kāi)環(huán)剛度和執(zhí)行器增益在水平方向上的受力所產(chǎn)生的力，可以準(zhǔn)確地近似截?cái)嗵├占?jí)數(shù)展開(kāi)的以下方式：如果在磁路平衡，然后在公式的第一項(xiàng)（6）等于零在《X代表和單位代表轉(zhuǎn)子位移控制的電磁線圈的電流。“鴨王是KX參數(shù)定義為KX的量稱為開(kāi)環(huán)剛度是由于水平位移在水平力的變化。開(kāi)環(huán)剛度是負(fù)的，這意味著軸承是不穩(wěn)定的開(kāi)環(huán)控制配置。不像一個(gè)正剛度彈簧位移，磁轉(zhuǎn)子會(huì)增加吸引力。它的數(shù)量表示軸承的執(zhí)行器增益。這是由于控制電流水平力的變化，垂直表達(dá)的成分存在等價(jià)表達(dá)式。用于開(kāi)環(huán)剛度和執(zhí)行器增益的表達(dá)式通過(guò)執(zhí)行當(dāng)差異化的力表達(dá)式來(lái)確定。這些表達(dá)式采取的形式那里的土地H代表長(zhǎng)度和退磁力，分別代表在永磁體和N是在電磁線圈的匝數(shù)?？刂葡到y(tǒng)說(shuō)明該系統(tǒng)的控制元件是檢測(cè)軸的運(yùn)動(dòng)的組件，確定所需的控制力，并由一個(gè)線圈電流所需的磁力軸承產(chǎn)生這種力量。該磁軸承系統(tǒng)有四個(gè)不同的組成部分：磁性致動(dòng)器，位移傳感器和相關(guān)的調(diào)理電路，模擬量控制器和功率放大器。實(shí)際的磁軸承主要由電磁線圈、鐵磁極片、轉(zhuǎn)子和永久磁鐵組成。信號(hào)調(diào)理元件由電渦流感應(yīng)位移傳感器、信號(hào)放大和坐標(biāo)轉(zhuǎn)換電路組成。模擬控制器主要由三個(gè)獨(dú)立的組件組成。組成比例（對(duì)）、積分（我）和派生（和）補(bǔ)償網(wǎng)絡(luò)的組成部分。這三個(gè)并聯(lián)階段通過(guò)相加放大器相加，以產(chǎn)生模擬控制器的輸出?？刂苹芈分械淖詈笠粋€(gè)組成部分是功率放大器。該放大器，根據(jù)控制器的要求，提供所需的電流，以產(chǎn)生必要的磁通在軸承的磁場(chǎng)線圈。軸承轉(zhuǎn)子系統(tǒng)的動(dòng)態(tài)可以結(jié)合控制電子的工作特性，形成一個(gè)閉環(huán)控制系統(tǒng)。該控制系統(tǒng)中的簡(jiǎn)化框圖形式中顯示。位移傳感器特性、模擬控制器和放大器組成了反饋控制器相對(duì)復(fù)雜的傳遞函數(shù)。反饋控制器將轉(zhuǎn)子位置與致動(dòng)器電流有關(guān)。此磁軸承系統(tǒng)的閉環(huán)傳遞函數(shù)，確定從這個(gè)框圖，給出4.控制系統(tǒng)描述四磁極徑向軸承定子，在設(shè)計(jì)上是相同的兩個(gè)軸承。定子和轉(zhuǎn)子的構(gòu)造3%硅鐵層壓材料，厚度為0.007英寸。每個(gè)層壓組件由約100片。疊片膠合在一起使用一部分活化劑/樹(shù)脂膠粘劑和形狀是電火花線切割加工（電火花加工。）軸承定子的外約3英寸，軸向長(zhǎng)度約0.7英寸。層片的外直徑約為1.5英寸。從軟磁鐵鐵的推軸承組件進(jìn)行加工。高能永磁體，由geodymium鐵硼合金有30毫克的OE最大磁能積。軸承支撐體重約3.7IBM軸。5.承載能力應(yīng)用于軸的最大負(fù)荷的測(cè)量，在失去支持，被繪制為一個(gè)函數(shù)的比例控制器增益KP，在這個(gè)測(cè)試中，在軸上懸掛重物。用這樣一種方式，該力可以施加在所需的方向上構(gòu)造一個(gè)滑輪系統(tǒng)。圖中的力表示沿軸承軸施加的力。在較低的比例增益的最大負(fù)載的變化實(shí)際上是一個(gè)衡量系統(tǒng)的穩(wěn)定性閾值。它是在式8注），開(kāi)環(huán)剛度，KX是定義在一個(gè)標(biāo)稱工作點(diǎn)，即轉(zhuǎn)子位置和控制電流等于零。然而，隨著軸承的靜載作用，穩(wěn)態(tài)電流開(kāi)始增加。它可以顯示分析，KX具有控制電流的工作點(diǎn)的功能。即為控制電流的增大，KX也增加。增加比例增益補(bǔ)償增加的KX從而提高系統(tǒng)穩(wěn)定性的影響。在較高比例的收益的測(cè)量代表了更準(zhǔn)確的測(cè)量軸承的實(shí)際負(fù)載能力。提供足夠的穩(wěn)定性，使磁飽和的軸承磁極結(jié)構(gòu)達(dá)到。最大預(yù)測(cè)載荷是在磁飽和點(diǎn)上計(jì)算的。6.等效軸承剛度和阻尼測(cè)量的軸承的等效剛度，這個(gè)簡(jiǎn)單的測(cè)量是通過(guò)施加一個(gè)恒定的力，進(jìn)