Simulink仿真演示外文翻译.docx

Simulink仿真演示外文翻译.docx

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Simulink仿真演示外文翻译

英文原文

SimulinkDemos

Simulinkisatoolformodeling,analyzing,andsimulatingphysicalandmathematicalsystems,includingthosewithnonlinearelementsandthosethatmakeuseofcontinuousanddiscretetime.

AsanextensionofMATLAB,SimulinkaddsmanyfeaturesspecifictodynamicsystemswhileretainingallofgeneralpurposefunctionalityofMATLAB.

RundemosforotherSimulinkproductsyouhaveinstalled.Trythesedemostosee

whichSimulinkproductsmightbeappropriatefortheworkyoudo.NotethatthisisacomprehensivelistofSimulinkproducts.YourparticularinstallationofMathWorks

IntheContentspane,foreachSimulinkproduct,seedocumentationExamplestoview

moresamplecodeyoucanrunorcopy.

Three-phaseThree-levelPWMConverter（discrete）

Thisdemonstrationillustratessimulationofa3-phase,3-levelinverterandDiscrete

3-phasePWMGenerator.ItalsodemonstratesharmonicanalysisofPWMwaveforms

usingthePowergui/FFTtool.

CircuitDescriptionThesystemconsistsoftwothree-phasethree-levelPWMvoltagesourceconverters

connectedintwinconfiguration。

TheinverterfeedsanACload（1kW,500var60Hz208Vrms）throughathree-phasetransformer.

Harmonicfilteringisperformedbythetransformerleakageinductance（8%）andload

capacitance（500var）.EachofthetwoinvertersusestheThree-LevelBridgeblock

wherethespecifiedpowerelectronicdevicesareIGBT/Diodearmconsists

of4

IGBTs,4antiparalleldiodes,and2neutralclampinginverteris

controlledinopenloop.PulsesaregeneratedbytheDiscrete3-PhaseDiscretePWM

Generatorblock.ThisblockisavailableintheExtras/DiscreteControlBlockslibrary.

ThisPWMgeneratorormodulatorcanbeusedtogeneratepulsesfor3-phase,2-level,

or3-levelconvertersusingonebridgeortwobridges（twinconfiguration）.Inthis

demo,thePWMmodulatorgeneratestwosetsof12pulses（1setperinverter）atP1

andP2outputs.Openthe'Discrete3-phasePWMGenerator'menu.Noticethatthe

generatorcanoperateeitherinsynchronizedorun-synchronizedmode.

Whenoperatinginsynchronizedmode,thecarriertriangularsignalissynchronizedon

aPLLreferenceangleconnectedtoinput'wt'.Insynchronizedmode,thecarrierchoppingfrequencyisspecifiedbytheswitchingratioasamultipleoftheoutputsinusoidal0.85pumodulatingsignalsareprovidedbythe'Discrete3-phaseProgrammableSource'toobtainamodulationindexof0.85.Thecarriersignalsaresynchronizedonthemodulatingsignals.inthePWMGeneratorblock,youcaninsteadselect'Un-synchronized'and'Internalgenerationofmodulatingsignals'.Insuchacasethemagnitude（modulationindex）,frequencyandphaseangleoftheoutputsignalsarespecified.directlyinsidethePWMGeneratorblockthisexampletheDCbusvoltageis400V（+/-200V）,choppingfrequencyis1080Hz（18*60Hz）,magnitudeofthethreemodulatingsignalsis0.85（correspondingtoamodulationindexm=0.85）andthefrequencyofthethreegeneratedsignalsis60ordertoallowfurthersignalprocessing,signalsdisplayedontheScopeblock（sampledatsimulationsamplingrateof3240samples/cycle）arestoredinavariablenamed'psb3phPWM3level_str'（structureswithtime）.

Demonstration

RunthesimulationandobservethefollowingthreewaveformsontheScopeblock:

Phase-neutralvoltageVan_inv1generatedbyinverter1（trace1）,phaseAvoltageVaa_invertergeneratedbythetwininverter（trace2）andphase-phaseloadvoltageVab_load（trace3）.TheVan_inv1waveformclearydemonstratesthethreelevels:

+200V,0V,and-200thesimulationiscompleted,openthePowerguiandselect'FFTAnalysis'todisplaythe0-5000Hzfrequencyspectrumofsignalssavedinthe'psb3phPWM3level_str'structure.TheFFTwillbeperformedona2-cyclewindowstartingatt=0.1-2/60（last2cyclesofrecording）.Selelecttheinputlabeled'Vaa_inverter'.ClickonDisplayandobservethefrequencyspectrumoflast2fundamentalcomponentofVaa_inverterandTHDforthe0-5000HzfrequencyrangearedisplayedabovethespectrumoftheforwardvoltagedropsintheIGBTs（Vf=1V）anddiodes（Vfd=1V）,themagnitudeofthefundamentalvoltageoftheinverter（335V）isslightlylowerthanthetheoreticalvalue（340Vform=0.85）.Asexpectedforatwininverter,firstharmonicsoccuraroundmultiplesofdoubleofcarrierfrequency（n*2*1080Hz+-k*60Hz）.Thesamecircuitusingtwo-levelinvertersintwinconfigurationisavailableinthepsb3phPWM.mdldemonstrationthisdemoandcomparetheharmoniccontentsinthe2-leveland3-levelinvertervoltageforthesamemodulationindex（m=0.85）.Harmonicsoccuratthesamefrequenciesbuttheirmagnitudeisapproximatelytwotimeslowerfora3-levelinverter.

DC/DCandDC/ACPWMConverters（discrete）

ThisdemonstrationillustratesuseoftheUniversalBridgeandDiscretePWMPulseGeneratorblocks.ItalsodemonstratesharmonicanalysisofPWMwaveformsusingthePowergui/FFTtool.

CircuitDescription

ThesystemconsistsofthreeindependantcircuitsillustratingvariousPWMDC/DCandDC/ACconvertersarecontrolledinopenloopwiththeDiscretePWMGeneratorblockavailableintheExtras/DiscreteControlBlockslibrary.

ThethreecircuitsusethesameDCvoltage（Vdc=400V）,carrierfrequency（1080Hz）

andmodulationindex（m=0.8）.Fromtoptobottom,thethreecircuitsare:

1.DC/DC,two-quadrantconverter（one-arm;two-switches）

2.DC/AC,bipolarconverter（one-arm;two-switches）

3.DC/AC,monopolarconverter（two-arms;four-switches）

Inordertoallowfurthersignalprocessing,signalsdisplayedonthethreeScope

blocks（sampledatsimulationsamplingrateof3240samples/cycle）arestoredinthree

variablesnamed'psb1phPWM1_str','psb1phPWM2_str'and'psb1phPWM3_str'

（structureswithtime）.

Demonstration

RunthesimulationandobservethefollowingtwowaveformsontheScopeblocks:

currentintotheload（trace1）,voltagegeneratedbythePWMinverter（trace2）.

Oncethesimulationiscompleted,openthePowerguiandselect'FFTAnalysis'to

displaythe0-5000Hzfrequencyspectrumofsignalssavedinthethree

'psb1phPWMx_str'structures.TheFFTwillbeperformedona2-cyclewindow

startingatt=0.1-2/60（last2cyclesofrecording）.ForeachcircuitselelectInput

labeled'Vinverter'.ClickonDisplayandobservethefrequencyspectrumoflast2

fundamentalcomponentofVinverter（DCcomponentincaseofcircuit

1）isdisplayedabovethespectrumthemagnitudeofthe

fundamentalorDCcomponentoftheinvertervoltagewiththetheoreticalvalues

giveninthecircuit.

Comparealsotheharmoniccontentsintheinvertervoltageforthetwo-switchand

four-switchDC/ACinverters.

Forthetwo-switchinverter,thefirstharmonicsoccuraroundthecarrierfrequency

（1080Hz+-k*60Hz,withamaximumof103%at1080Hz）,

whereasforthefour-switchinverterharmonicsarelowerandappearatdoubleof

carrierfrequency（maximumof40%at2*1080+-60Hz）.Asaresult,thecurrentis

"cleaner"forthefour-switchinverter.

IfyounowperformaFFTonthesignalIloadyouwillnoticethattheTHDofload

currentis7.3%forthetwo-switchinverterascomparedtoonly2%forthe

four-switchinverter。

CircuitDescription

Athree-phasemotorrated3HP,220V,1725rpmisfedbyasinusoidalPWM

inverter.Thebasefrequencyofthesinusoidalreferencewaveis60Hzwhilethe

triangularcarrierwave'sfrequencyissetto1980Hz.

ThePWMinverterisbuiltentirelywithstandardSimulinkblocks.Itsoutputgoes

throughControlledVoltageSourceblocksbeforebeingappliedtotheAsynchronous

Machineblock'sstatorwindings.Themachine'srotorisshort-circuited.Itsstator

leakageinductanceLlsissettotwiceitsactualvaluetosimulatetheeffectofa

smoothingreactorplacedbetweentheinverterandthemachine.Theloadtorque

appliedtothemachine'sshaftisconstantandsettoitsnominalvalueof11.9N.m.Themotorisstartedfromstall.Thespeedsetpointissetto1.0pu,or1725rpm.This

speedisreachedafter0.9s.

Demonstration

Takealookatthesimulationparameters.TheMaximumtimestephasbeenlimitedto

10microseconds.

Thisisrequiredduetotherelativelyhighswitchingfrequency（1980Hz）ofthe

inverter.

Observethattherotorandstatorcurrentsarequite"noisy,"despitetheuseofa

smoothingreactor.ThenoiseintroducedbythePWMinverterisalsoobservedinthe

electromagnetictorquewaveformTe.However,themotor'sinertiapreventsthisnoise

fromappearinginthemotor'sspeedwaveform.TheRMSvalueofthefundamentalcomponentofthelinevoltageatthemachine's

statorterminalsisextractedwithaFourierblock,whichcanbefoundinthe

MeasurementsgroupoftheExtraslibrary.

Finally,observethePWMinverter'soutput.Usethezoomonthevaboscilloscopeto

zoominonthewaveform.

Simple6-pulseHVDCTransmissionSystem（discrete）

Thisdemonstrationillustratessteady-stateandtransientperformance

ofasimple500MW（250kV-2kA）HVDCtransmissionsystem

CIRCUITDESCRIPTION

A500MW（250kV,2kA）DClinterconnexionisusedtotransmitpowerfroma315

kV,5000MVAACnetwork.ThenetworkissimulatedbyaLLRdampedequivalent

（impedanceangleof80degreesat60Hzand3rdharmonic）.Theconverter

transformerandtherectifieraremodelledrespectivelywiththeUniversal

TransformerandUniversalBridgeblocksTheconverterisa6-pulserectifier.Itis

connectedtoa300kmdistributedparameterlinethrougha0.5Hsmoothingreactor

inverterissimulatedbyasimpleDCvoltagesourceinserieswithadiode（to

forceunidirectionalconduction）andsmoothingreactorreactivepower

requiredbytheconverterisprovidedbyasetoffilters（Cbankplus5th,7thandhigh

passf