Vector control motorWord下载.docx

Vector control motorWord下载.docx

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AC 

synchronous 

and 

inductionmotors.[2] 

Itwasoriginallydevelopedforhigh-performancemotorapplicationsthatarerequiredtooperatesmoothlyoverthefull 

speed 

range,generatefull 

torque 

atzerospeed,andhavehighdynamicperformanceincludingfast 

acceleration 

anddeceleration.However,itisbecomingincreasinglyattractiveforlowerperformanceapplicationsaswellduetoFOC'

smotorsize,costand 

powerconsumption 

reductionsuperiority.[3][4] 

Itisexpectedthatwithincreasingcomputationalpowerofthemicroprocessorsitwilleventuallynearlyuniversallydisplacesingle-variable 

scalar 

volts-per-Hertz 

（V/f）control.[5][6]

Contents

[hide] 

∙1 

Developmenthistory

∙2 

Technicaloverview

∙3 

Applicationrecap

∙4 

Seealso

∙5 

References

Developmenthistory[edit]

BlockdiagramfromBlaschke'

s1971USpatentapplication

TechnicalUniversityDarmstadt'

sK.HasseandSiemens'

F.Blaschkepioneered 

vector 

controlofACmotorsstartingin1968andintheearly1970s,Hasseintermsofproposingindirectvectorcontrol,Blaschkeintermsofproposingdirectvectorcontrol.[7][8] 

TechnicalUniversityBraunschweig'

sWernerLeonhardfurtherdevelopedFOCtechniquesandwasinstrumentalinopeningupopportunitiesfor 

ACdrives 

tobeacompetitivealternativeto 

DCdrives.[9][10]

Yetitwasnotuntilafterthecommercializationof 

microprocessors,thatisintheearly1980s,thatgeneralpurposeACdrivesbecameavailable.[11][12] 

BarrierstouseofFOCforACdriveapplicationsincludedhighercostandcomplexityandlowermaintainabilitycomparedtoDCdrives,FOChavinguntilthenrequiredmanyelectroniccomponentsintermsofsensors,amplifiersandsoon.[13]

The 

Parktransformation 

haslongbeenwidelyusedintheanalysisandstudyof 

andinductionmachines.ThetransformationisbyfarthesinglemostimportantconceptneededforanunderstandingofhowFOCworks,theconcepthavingbeenfirstconceptualizedina1929paperauthoredby 

RobertH.Park.[14] 

Park'

spaperwasrankedsecondmostimportantintermsofimpactfromamongallpowerengineeringrelatedpaperseverpublishedinthetwentiethcentury.ThenoveltyofPark'

sworkinvolveshisabilitytotransformanyrelatedmachine'

slinear 

differentialequationsetfromonewithtimevaryingcoefficientstoanotherwithtime 

invariant 

coefficients.[15]

Technicaloverview[edit]

OverviewofkeycompetingVFDcontrolplatforms:

VFD,withsensororsensorless

Scalarcontrol

V/f（VoltsperHertz）control

Vectorcontrol

DTC（Directtorquecontrol）

DSC（Directself-control）

SVC（Spacevectormodulation）

FOC（Field-orientedcontrol）

DirectFOC

IndirectFOC

SignalFlowGraph（SFG）forInductionMotor

SFGEquations

（d,q）CoordinateSystemSuperimposedonThree-PhaseInductionMotor[16]

SimplifiedIndirectFOCBlockDiagram 

[3] 

[17][18]

SimplifiedDirectFOCBlockDiagram 

[19]

SensorlessFOCBlockDiagram 

[20][21]

WhiletheanalysisofACdrivecontrolscanbetechnicallyquiteinvolved（"

Seealso"

section）,suchanalysisinvariablystartswithmodelingofthedrive-motorcircuitinvolvedalongthelinesofaccompanying 

signalflowgraph 

andequations.[20]

Invectorcontrol,anACinductionorsynchronousmotoriscontrolledunderalloperatingconditionslikeaseparately 

excited 

DCmotor.[22] 

Thatis,theACmotorbehaveslikeaDCmotorinwhichthefieldfluxlinkage 

armature 

fluxlinkagecreatedbytherespectivefieldandarmature（ortorquecomponent）currentsare 

orthogonally 

alignedsuchthat,whentorqueiscontrolled,thefieldfluxlinkageisnotaffected,henceenablingdynamictorqueresponse.

Vectorcontrolaccordinglygeneratesathree-phase 

PWM 

motorvoltageoutputderivedfroma 

complexvoltagevectortocontrolacomplexcurrentvectorderivedfrommotor'

sthree-phasemotorstatorcurrentinputthrough 

projections 

or 

rotations 

backandforthbetweenthethree-phasespeedandtimedependentsystemandthesevectors'

rotatingreference-frametwo-coordinate 

timeinvariantsystem.[23]

Suchcomplex 

motorcurrentspacevectorcanbedefinedina（d,q）coordinatesystemwithorthogonalcomponentsalongd（direct）andq（quadrature）axessuchthatfieldfluxlinkagecomponentofcurrentisalignedalongthedaxisandtorquecomponentofcurrentisalignedalongtheqaxis.[22] 

Theinductionmotor'

s（d,q）coordinatesystemcanbesuperimposedtothemotor'

sinstantaneous（a,b,c）three-phase 

sinusoidal 

systemasshowninaccompanyingimage（phasesa&

bnotshownforclarity）.Componentsofthe（d,q）systemcurrentvector,allowconventionalcontrolsuchasproportionalandintegral,or 

PI,control,aswithaDCmotor.

Projectionsassociatedwiththe（d,q）coordinatesystemtypicallyinvolve:

[20][23][24]

∙Forwardprojectionfrominstantaneouscurrentsto（a,b,c）complex 

currentspacevectorrepresentationofthethree-phase 

system.

∙Forwardthree-to-twophase,（a,b,c）-to-（

）projectionusingthe 

Clarke 

transformation.Vectorcontrolimplementationsusuallyassumeungroundedmotorwithbalancedthree-phasecurrentssuchthatonlytwomotorcurrentphasesneedtobesensed.Also,backwardtwo-to-threephase,（

）-to-（a,b,c）projectionusesspacevectorPWMmodulatororinverseClarketransformationandoneoftheotherPWMmodulators.

∙Forwardandbackwardtwo-to-twophase,（

）-to-（d,q）and（d,q）-to-（

）projectionsusingtheParkandinverseParktransformations,respectively.

However,itisnotuncommonforsourcestousethree-to-two,（a,b,c）-to-（d,q）andinverseprojections.

While（d,q）coordinatesystemrotationcanarbitrarilybesettoanyspeed,therearethreepreferredspeedsorreferenceframes:

[16]

∙Stationaryreferenceframewhere（d,q）coordinatesystemdoesnotrotate;

∙Synchronouslyrotatingreferenceframewhere（d,q）coordinatesystemrotatesatsynchronousspeed;

∙Rotorreferenceframewhere（d,q）coordinatesystemrotatesatrotorspeed.

Decoupled 

torqueandfieldcurrentscanthusbederivedfromrawstatorcurrentinputsforcontrolalgorithmdevelopment.[25]

WhereasmagneticfieldandtorquecomponentsinDCmotorscanbeoperatedrelativelysimplybyseparatelycontrollingtherespectivefieldandarmaturecurrents,economicalcontrolofACmotorsinvariablespeedapplicationhasrequireddevelopmentofmicroprocessor-basedcontrols[25] 

withallACdrivesnowusingpowerfulDSP（digitalsignalprocessing）technology.[26]

Inverterscanbeimplementedaseither 

open-loop 

sensorlessorclosed-loopFOC,thekeylimitationofopen-loopoperationbeingmimimumspeedpossibleat100%torque,namely,about0.8 

Hzcomparedtostandstillforclosed-loopoperation.[9]

Therearetwovectorcontrolmethods,director 

feedback 

vectorcontrol（DFOC）andindirectorfeedforward 

vectorcontrol（IFOC）,IFOCbeingmorecommonlyusedbecauseinclosed-loopmodesuchdrivesmoreeasilyoperatethroughoutthespeedrangefromzerospeedtohigh-speedfield-weakening.[27] 

InDFOC,fluxmagnitudeandanglefeedbacksignalsaredirectlycalculatedusingso-calledvoltageorcurrentmodels.InIFOC,fluxspaceanglefeedforwardandfluxmagnitudesignalsfirstmeasurestatorcurrentsand 

rotor 

speedforthenderivingfluxspaceangleproperbysummingtherotoranglecorrespondingtotherotorspeedandthecalculatedreferencevalueof 

slip 

anglecorrespondingtotheslipfrequency.[28][29]

Sensorlesscontrol（seeSensorlessFOCBlockDiagram）ofACdrivesisattractiveforcostandreliabilityconsiderations.Sensorlesscontrolrequiresderivationofrotorspeedinformationfrommeasuredstatorvoltageandcurrentsincombinationwithopen-loopestimatorsorclosed-loopobservers.[20][21]

Applicationrecap[edit]

1.Statorphasecurrentsaremeasured,convertedtocomplexspacevectorin（a,b,c）coordinatesystem.

2.Currentvectorisconvertedto（

）coordinatesystem. 

Transformedtoacoordinatesystem 

rotatingin 

referenceframe,rotorpositionbeingderivedby 

integrating 

thespeedbymeansof 

speedmeasurement 

sensor.

3.Rotor 

fluxlinkage 

vectorisestimatedbymultiplyingthestatorcurrentvectorwithmagnetizinginductanceLm 

low-passfiltering 

theresultwiththerotorno-load 

timeconstant 

Lr/Rr,namely,therotorinductancetorotorresistanceratio.

4.Currentvectorisconvertedto（d,q）coordinatesystem.

5.d-axiscomponentofthestatorcurrentvectorisusedtocontroltherotorfluxlinkageandtheimaginaryq-axiscomponentisusedtocontrolthemotortorque.WhilePIcontrollerscanbeusedtocontrolthesecurrents, 

bang-bang 

typecurrentcontrolprovidesbetterdynamicperformance.

6.PIcontrollersprovide（d,q）coordinatevoltagecomponents.Adecouplingtermissometimesaddedtothecontrolleroutputtoimprovecontrolperformancetomitigatecrosscouplingorbigandrapidchangesinspeed,currentandfluxlinkage.PI-controlleralsosometimesneed 

attheinp