传感器SRM驱动器中英文对照外文翻译文献.docx

传感器SRM驱动器中英文对照外文翻译文献.docx

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传感器SRM驱动器中英文对照外文翻译文献

中英文对照翻译

（文档含英文原文和中文翻译）

ASimpleExcitationPositionDetectionMethodforSensorlessSRMDrive

Acknowledgements

TheresearchforthispaperwasperformedinDr.G.Schröder’slaboratoryduringMr.Kim’s2006summerinternprogramofSiegenUniversity,Germany.TheauthorsthankKRF（KoreaResearchFoundation）forsupportingtheprogram.

Keywords

«SwitchedReluctanceDrive»,«SensorlessControl»

Abstract

ThispaperdescribesasimplifiednovelsensorlesscontrolofanSRMbydetectingacurrentlevelduringthenon-excitationperiod.Sincetheinductanceofthemotorisafunctionoftherotorposition,asimpledetectingcurrentpulsecausedbyaregulatedpulsevoltagegivesinformationontherotorposition.Inthispaper,asmalldetectingpulsecurrentiscomparedtothepresetcurrentlevelswhichareproportionaltoturn-onandturn-offpositions.Andthecomparisonresultsareusedfortheexcitationofthenextphase.Thesuggestedmethodisverifiedbysomesimulationsandexperimentaltests.

Introduction

Aswitchedreluctancemotor（hereinafterreferredtoasan“SRM”）isapowerdrivedevicewhichcanbeeasilyandinexpensivelymanufactured,andithasrelativelyhighreliabilitysinceitisproofagainstcertaindrivefaults.Hence,anSRMdrivesystemhassomecharacteristicscomparablewithanexistinginductionmotorinviewofhightorque,ahighoutputdensity,ahigh-efficientvariablespeeddrive,andaneconomicpowerinverterinapplicationfieldssuchasindustrialmachinery,airplanes,automobiles,consumerdevices,andothers[1-2].

InthecontrolofanSRM,onaccurateinformationofrotorpositionisessentialforcorrectphasewindingexcitation.Sincetheoutputtorqueisdependentontheexcitationperiodandexcitedphasecurrent,theaccuracyoftherotorpositionisveryimportant.Inageneralspeedcontrolsystem,anopticalencoderiswidelyusedfordetectingoftherotorposition.Recently,sensorlesscontrolandpositiondetectingtechniquesareinterestinginpracticalapplicationsduetoproblemsofopticalencoderinharshenvironmentandcost.

Inordertogetasensorlessrotorposition,mathematicalbasedobserversandfluxdetectingmethodsareused[3-6].Sincetheaccuracyoftheestimatedrotorpositionofanobserverisdependentonthe

mathematicalmodelandelectricalparameters,theestimationerrorislargeinthelowspeedrange.Anditisverydifficulttogettherotorpositioninstandstill.Althoughthefluxdetectingmethodcaneasilyestimatetherotorpositionwithoutanycomplexmathematicalmodel,alook-uptableoffluxandrotorpositionisrequired.Andtherelationshipoffluxandrotorpositionhasnon-linearcharacteristicduetothesaturationeffect.Recently,fuzzylogicandANN（ArtificialNeuralNetworks）havebeenusedinspeedestimation[7-8]

Thispaperpresentsasimplifiednovelapproachofsensorlesscontrolwithoutacomplexcalculationoftherotorpositionfromtheestimatedinductance.Sincetheoutputtorqueisdependentonexcitationpositionandexcitedcurrent,theproposedsensorlessschemedeterminestheexcitationpatternonlyfromthedetectingcurrentinanon-excitedphasewindingduringthedetectingperiod.Theturn-onandturn-offpositionsaredeterminedbythedetectingphasecurrentlevelsthatareinverse-proportionaltorotorpositioninthedetectingperiodofthepreviouslyexcitedphase.Inordertogetalinearrelationshipbetweenrotorpositionanddetectedphasecurrent,ashorttestvoltageisappliedduringthedetectingperiod.Sincetheproposedsensorlessschemedoesnotuseacomplexinductancecalculation,theexcitationpatterncanbeeasilydeterminedbyasimplecomparator.Thesuggested

methodisverifiedbysomesimulationsandexperimentaltests.

TheGeneralPrinciplesofSRM

Fig.1showsanSRdrivesystemanditstorquecharacteristics.IntheFig.1,theoutputtorqueisproducedintheinductancevariationregionshowninFig.1（b）.

（a）SRdrivesystem

（b）Torquecharacteristicswithconstantcurrent

Fig.1:

SRdrivesystemandtorquecharacteristics

Theoutputtorquecanbeexplainedbytherelationshipofcurrentandinductanceasfollows.

Inordertoestimatethephaseinductance,thephasecurrentexcitedbyaswitchingtestpulsevoltageisusedateverysamplingperiodshownasFig.2.

Fig.2:

Waveformoftestpulsevoltageandphasecurrentforinductanceestimation

Thevoltageequationforestimatingthephaseinductancecanbederiveddisregardingthevoltage

dropofthephaseresistanceandtheback-emf.From

（2）,thephaseinductancethatisafunctionofthe

rotorpositioniscalculated,andtherotorpositionisestimatedfromthecalculatedinductance

accordingto（3）.Inspiteofacomplexcalculation,theestimatedrotorpositionfromthecalculated

inductancehassomeerrorduetothesaturationeffectincludingthenon-linearcharacteristicsofthe

inductanceandthevoltagedropofthephaseresistance.

TheProposedSensorlessControlSchemeofSRM

SwitchingPatternDetermination

Fig.3:

Theproposeddetectingschemeofsensorlessexcitation

Fig.3showstheproposeddetectingalgorithmofthesensorlessexcitationofthe3-phaseSRM.Differentlyfromageneralexcitationmethod,theproposedschemehasexcitation,detectingandnonexcitationperiodsineachphase.

Intheexcitationperiodwhichisdeterminedbytheothersnon-excitedphases,excitedphasecurrentproducesoutputtorque.Andtheappliedvoltageofeachphasewindingintheexcitationperiodiscontrolledbythespeedcontrollerandexcitationcurrentcontroller.Theamplifieddetectedcurrentinthedetectingperiod,iscomparedtopresetturn-onandturn-offcurrents,IonandIoffwhicharedeterminedbyposition-currentcharacteristicoftheproto-typeSRM.Thecomparisonresultofferstheotherphase’sturn-onandturn-offpositionθonandθoff,respectively.Inthenon-excitationperiod,thephasecurrentdoesnotflowthroughthephasewinding.Inthedetectingperiod,theamplifieddetectedcurrenthasnearlylinearslopeduetothedecreasingphaseinductance.Sincethewidthofthetestpulsevoltageisverynarrowandthedetectedcurrentisverysmall,saturationeffectofphase

inductancecanbeignored.Sotheslopeofthedetectingcurrentislinearaccordingtorotorpositionineachphasewindings.Butthedetectingperiodofanun-excitedphaseislocatedinthenegativetorqueregionshownasFig.2.SincethedetectingphasecurrentproducesnegativetorqueandDC-linkvoltagecanbechanged,testpulsevoltageshouldbelimitedandcontrolledforthestableoperation.Inordertolimitthenegativetorqueproducedfromdetectingcurrent,thedurationoftestpulsevoltageiscontrolledaccordingtoDC-linkvoltageinthispaper.ThemaximumdetectingphasecurrentisproducedintheminimuminductancerangeandthedetectingperiodofvoltagepulsecanbederivedasfollowswithnegativetorquelimitTNLMT.Inthispaper,thenegativetorquelimitTNLMTisdeterminedas2%ofratedtorqueofSRM,andthemaximumperiodoftestpulseislimitedto20[us].

where,θmaxandθminaretherotorpositionofmaximuminductance,Lmaxandminimuminductance,Lmin,respectively.

Fig.4showsthedetailedblockdiagramofthesensorlessswitchingpositiondetectingmethod.Theproposedturn-onandturn-offpositionestimatorconsistsofthepositionlevelgeneratorandthecurrentlevelcomparator.Thepositionlevelgeneratorproducesturn-onandturn-offcurrentlevelsfrompre-calculatedlook-uptable.

Fig.4:

Theblockdiagramoftheproposedsensorlessswitchingpositiondetection

Thecontentofthelook-uptableissimplymeasuredwithafixedtestvoltagepulseaccordingtorotorposition.Becausethetestvoltagepulseisshortduetothelimitationofnegativetorqueproduction,theoutputcurrentlevelsareapproximatelyinverseproportionaltotheinductance.Ifthesensorlesscontrolsystemusesafixedturn-onandturn-offposition,thelook-uptablecanbeomitted.Sincethedetectingpulsecurrentisverysmallduetothelimitationofnegativetorque,itisamplifiedandlimitedabyzenerdiode.Thereferenceturn-onandturn-offposition,θ*on,θ*offchangewithIonandIofffromtheposition-currentlook-uptable.Thelook-uptableissimplepre-measuredwithtestpulses.Andthepresetturn-onandturn-offpositioncurrentarecomparedtotheamplifieddetectingcurrent.Thetriggerpulsesaregeneratedwhenthedetectingcurrentislargertheneachpresetvalue.ThetriggerpulsesareinputasinterruptsoftheDSP,andestimatedturn-on,turn-offpositionare

determined.Therotorspeedissimplyestimatedbytheestimatedturn-onandturn-offpositionofeachphase.

TheExcitationPhaseandPositionatStandstill

Inthestandstill,thefirstswitchingpatternisdeterminedfromdetectingcurrentexplainedintheFig.4.Itshowstherelationshipbetweendetectingcurrentandeachpossiblepositionatstandstill.Intheidealcase,pointa0,b0andc0whichthemaximumperiodofeachdetectingcurrentarethecriticalboundaryforthefirstexcitationphase.

Fig.5:

Thedetectingcurrentsofeachphaseaccordingtothestandstillposition

TheExperimentalResults

Inordertoverifytheproposedsensorlessscheme,a12/8SRMandaDSPcontrollerwith

asymmetricconverterareused.Table1showsthespecificationsofthe12/8SRMundertest.ThemaincontrollerisimplementedbyaTMS320F2812fromTexasInstrumentsanda600V/25AasymmetricconvertermoduleSK25GAD063TfromSEMIKRON.

Fig.6:

Theexperimentset-up

TheproposedsensorlessPIcontrollerisimplementedinaTMS320F2812.Anencoderisusedforpositionmonitoring.TheasymmetricconverterislocatedundertheDS