高速旋转机械中英文对照外文翻译文献

外文资料翻译中英文对照外文翻译文献(文档含英文原文和中文翻译)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.高速旋转机械的低功率磁力轴承设计总结:磁悬液研究具有先进的研发技术，有一定的优势，广泛应用于旋转机械和航空航天等领域。最突出的优势，磁力轴承比传统的轴承功耗少。电磁铁是一个十分具有吸引力的选择，它可以进一步降低轴承的功耗。一组永久磁铁偏置，主动控制的磁轴承的柔性转子。永久磁铁和电磁铁的配置有效地提供通量在合适的气隙，同时将不稳定力量降到最低。该设计包括2个径向轴承和一个推力轴承。对设计理论和发展进行了简要讨论。一组操作的原型轴承的实验性能结果如下，结果包括负载能力的测量，轴承刚度和阻尼和转子的动态响应。有几个情况是例外，实验测量相匹配的预测性能非常好，这些轴承的功率消耗显减少。简介:磁力轴承有许多优点。一个最明显的优势是无摩擦的特点。整个润滑系统和机械油封，这增加了摩擦损失和不稳定性与交叉耦合轴承系数，可以消除这些类型的轴承的摩擦。一个磁力轴承的寿命，在正常情况下，可以远高于传统的轴承。由于好性质的轴承，机械零件不磨损。这可以明显提高系统的可靠性，降低成本的维修，中断盈利机器操作。如果设计得当，磁轴承工作的时间是不可能与其他类型的轴承长时间在严酷的条件和环境下进行。对于这些轴承的摩擦特性，另一个优点是功率损失。传统的流体膜轴承的功率消耗无时无刻，远远超过了磁性轴承。当一台机器使用传统的轴承到换用磁力轴承的时候，可以从一个数量级或更高的减少功率损耗。各种各样的程序完成了一些不同的工作和磁性轴承的运行。许多研究人员和工业研究人员已经进行了大量的实验研究，工业屏蔽电机泵的磁轴承的发展[1],和多磁轴承在工业广泛应用已被魏泽[2]报道。为挠性转子振动控制系统的开发与应[4]，成功研制出一种基于微机的磁力轴承数字控制器。正在进行的数字和自适应控制的磁轴承的持续研究，在研究永磁体结合电磁铁的使用，两个专利归功于菲利普[5，6]。这些专利包含了一些内容，主要是处理永久磁铁，这有助于本文讨论的轴承。Wilson和斯图~二[7]也应用了永磁偏置的概念，在一个直线运动轴承。ohkami等人[8]对使用永久磁铁的各种结构的磁力轴承进行了一些有意义的比较研究。土屋等人的另一篇论文，[9]悬浮于永磁体的磁悬浮转子高速转子稳定性的研究与评价。米克斯[10]还说出各种磁轴承的设计方法并进行比较和总结，控制电磁铁与磁轴承的永久磁铁的作用相结合，重量和功耗减少，今天的稀土永磁体，特别是钕铁磁体，拥有非常高的性能特点，在磁场强度，能源产品和热质量方面。磁铁设计人员能够将大量的磁能量集中在一个小的包中，使得更有效地利用可用空间。对永磁偏置磁轴承的设计本文设计的概念是由Studer[5报告的研究和发展变化，6]。下面两节简要说明如何在概念上操作的轴承。1.组合径向/推力磁轴承描述此轴承设计，揭示了各种磁性路径，这种轴承的径向和推力相结合的控制。轴承的径向部分是相同的，这是在上一节中描述的。然而，推力控制，实现由一个独特的磁通配置。永久磁铁的偏置磁通通过沿轴分裂之前，两个推力杆，返回到永久磁铁。一个积极的线圈产生磁场，在一个环形的形状，对称添加或减去在推力盘与推力杆之间的工作气隙磁偏置。2.设计理念本课题设计的轴承是不同于所有电磁轴承的设计中，他们采用永久磁铁和电磁铁。永久磁铁产生的偏置磁场在工作间隙和电磁铁是用来调节这个流量。在工作间隙建立偏置磁场的目的是对磁驱动器的控制力方程线性化。偏置磁通是一个额定磁通密度的控制磁通变化的。如果零的偏置磁通，（只有一个相对的致动器操作的时间，），然后由致动器所产生的致动器的转子上的二次力法，即，该力将在空气间隙中的磁通密度的平方成正比。因此，强制转换率将是零，当转子处于额定平衡位置和瞬态响应将受到不利影响。如果，轴承磁通调制约一个非零的偏置磁通，（与相对的致动器对称扰动），很容易地表明，力与控制磁通呈线性关系。下面的部分演示了这个重要关系。力量关系磁性致动器产生的空气间隙中的空气间隙的力可以表示由直接关系BG在空气间隙和J.Lo的磁通密度是具有自由空间的通透性。如果仅仅是一个轴的轴承被认为具有这种特性，由于轴上的净力作用，两个相反的作用致动器力的差异。假设两者的相对空气间隙的区域是相同的，通过磁力轴承作用于轴上的力可以表示为F。空气间隙中的磁通密度由2个源提供，即永磁体和线圈。为了正确地提供差分控制，在2个间隙的磁通对称扰动，一个间隙中的磁通增加，而相反的间隙中的磁通减少相同的量。这意味着BPM产生的永久磁铁的磁通密度和由线圈产生的磁通密度。替代式。L3、4）代入式（2），扩展和简化，作用在轴可以表示为Y表示对这种形式的轴力的方程，需要注意的是，力不仅是偏置电平，BPM比例很有趣，但它也是线性化控制流量。开环刚度和执行器增益在水平方向上的受力所产生的力，可以准确地近似截断泰勒级数展开的以下方式：如果在磁路平衡，然后在公式的第一项（6）等于零在《X代表和单位代表转子位移控制的电磁线圈的电流。“鸭王是KX参数定义为KX的量称为开环刚度是由于水平位移在水平力的变化。开环刚度是负的，这意味着轴承是不稳定的开环控制配置。不像一个正刚度弹簧位移，磁转子会增加吸引力。它的数量表示轴承的执行器增益。这是由于控制电流水平力的变化，垂直表达的成分存在等价表达式。用于开环刚度和执行器增益的表达式通过执行当差异化的力表达式来确定。这些表达式采取的形式那里的土地H代表长度和退磁力，分别代表在永磁体和N是在电磁线圈的匝数。控制系统说明该系统的控制元件是检测轴的运动的组件，确定所需的控制力，并由一个线圈电流所需的磁力轴承产生这种力量。该磁轴承系统有四个不同的组成部分：磁性致动器，位移传感器和相关的调理电路，模拟量控制器和功率放大器。实际的磁轴承主要由电磁线圈、铁磁极片、转子和永久磁铁组成。信号调理元件由电涡流感应位移传感器、信号放大和坐标转换电路组成。模拟控制器主要由三个独立的组件组成。组成比例（对）、积分（我）和派生（和）补偿网络的组成部分。这三个并联阶段通过相加放大器相加，以产生模拟控制器的输出。控制回路中的最后一个组成部分是功率放大器。该放大器，根据控制器的要求，提供所需的电流，以产生必要的磁通在轴承的磁场线圈。轴承转子系统的动态可以结合控制电子的工作特性，形成一个闭环控制系统。该控制系统中的简化框图形式中显示。位移传感器特性、模拟控制器和放大器组成了反馈控制器相对复杂的传递函数。反馈控制器将转子位置与致动器电流有关。此磁轴承系统的闭环传递函数，确定从这个框图，给出4.控制系统描述四磁极径向轴承定子，在设计上是相同的两个轴承。定子和转子的构造3%硅铁层压材料，厚度为0.007英寸。每个层压组件由约100片。叠片胶合在一起使用一部分活化剂/树脂胶粘剂和形状是电火花线切割加工（电火花加工。）轴承定子的外约3英寸，轴向长度约0.7英寸。层片的外直径约为1.5英寸。从软磁铁铁的推轴承组件进行加工。高能永磁体，由geodymium铁硼合金有30毫克的OE最大磁能积。轴承支撑体重约3.7IBM轴。5.承载能力应用于轴的最大负荷的测量，在失去支持，被绘制为一个函数的比例控制器增益KP，在这个测试中，在轴上悬挂重物。用这样一种方式，该力可以施加在所需的方向上构造一个滑轮系统。图中的力表示沿轴承轴施加的力。在较低的比例增益的最大负载的变化实际上是一个衡量系统的稳定性阈值。它是在式8注），开环刚度，KX是定义在一个标称工作点，即转子位置和控制电流等于零。然而，随着轴承的静载作用，稳态电流开始增加。它可以显示分析，KX具有控制电流的工作点的功能。即为控制电流的增大，KX也增加。增加比例增益补偿增加的KX从而提高系统稳定性的影响。在较高比例的收益的测量代表了更准确的测量轴承的实际负载能力。提供足够的稳定性，使磁饱和的轴承磁极结构达到。最大预测载荷是在磁饱和点上计算的。6.等效轴承刚度和阻尼测量的轴承的等效刚度，这个简单的测量是通过施加一个恒定的力，进