電力電子技術（第5版）(英文版)課件：整流電路

Power

Electronics整流電路ACtoDCConverters(Rectifiers)Outline3.1Single-phasecontrolledrectifier3.2Three-phasecontrolledrectifier3.3Effectoftransformerleakageinductanceon

rectifiercircuits3.4Capacitor-filtereduncontrolledrectifier3.5Harmonicsandpowerfactorofrectifiercircuits3.6Highpowercontrolledrectifier3.7Invertermodeoperationofrectifiercircuit3.8Realizationofphase-controlinrectifiercircuits3.1Single-phasecontrolled

(controllable)rectifier3.1.1Single-phasehalf-wavecontrolledrectifier3.1.2Single-phasebridgefully-controlledrectifier3.1.3Single-phasefull-wavecontrolledrectifier3.1.4Single-phasebridgehalf-controlledrectifier3.1.1Single-phasehalf-wave

controlledrectifierHalf-wave,single-pulseTriggeringdelayangle,delayangle,firingangleResistiveload(3-1)3.1.1Single-phasehalf-wave

controlledrectifierInductive(resistor-inductor)loadBasicthoughtprocessoftime-domainanalysisforpowerelectroniccircuitsThetime-domainbehaviorofapowerelectroniccircuitisactuallythecombinationofconsecutivetransientsofthedifferentlinearcircuitswhenthepowersemiconductordevicesareindifferentstates.ωt=

a

，id=0(3-3)(3-2)Single-phasehalf-wavecontrolledrectifierwithfreewheelingdiodeMaximumforwardvoltage,maximumreversevoltageDisadvantages:OnlysinglepulseinonelinecycleDCcomponentinthetransformercurrentInductiveload(Lislargeenough)VTia)Tu1u2uVTLRdudVDiRVDR(3-5)(3-6)(3-7)(3-8)3.1.2Single-phasebridge

fully-controlledrectifierForthyristor:maximumforwardvoltage,maximumreversevoltageAdvantages:2pulsesinonelinecycleNoDCcomponentinthetransformercurrentResistiveloaddRTu1u2i2abVT1VT3VT2VT4udia)3.1.2Single-phasebridgefully-

controlledrectifierResistiveloadAverageoutput(rectified)voltage (3-9)Averageoutputcurrent(3-10)Forthyristor(3-11)(3-12)Fortransformer(3-13)3.1.2Single-phasebridge

fully-controlledrectifierCommutationThyristorvoltagesandcurrentsTransformercurrentInductiveload

(Lislargeenough)(3-15)Electro-motive-force(EMF)loadDiscontinuouscurrentidWithresistorElectro-motive-force(EMF)loadWithresistorandinductorWhenLislargeenough,theoutputvoltageandcurrentwaveformsarethesameasordinaryinductiveload.WhenLisatacriticalvalue(3-17)3.1.3Single-phasefull-wave

controlledrectifierTransformerwithcentertapComparisonwithsingle-phasebridgefully-controlledrectifier3.1.4Single-phasebridge

half-controlledrectifierHalf-controlComparisonwithfully-controlledrectifierAdditionalfreewheelingdiodeabRLu2i2udidVT1VT2VD3VD4VDRTAnothersingle-phasebridge

half-controlledrectifierComparisonwithpreviouscircuit:NoneedforadditionalfreewheelingdiodeIsolationisnecessarybetweenthedrivecircuitsofthetwothyristorsSummaryofsomeimportantpointsinanalysisWhenanalyzingathyristorcircuit,startfromadiodecircuitwiththesametopology.Thebehaviorofthediodecircuitisexactlythesameasthethyristorcircuitwhenfiringangleis0.Apowerelectroniccircuitcanbeconsideredasdifferentlinearcircuitswhenthepowersemiconductordevicesareindifferentstates.Thetime-domainbehaviorofthepowerelectroniccircuitisactuallythecombinationofconsecutivetransientsofthedifferentlinearcircuits.TakedifferentprinciplewhendealingwithdifferentloadForresistiveload:currentwaveformofaresistoristhesameasthevoltagewaveformForinductiveloadwithalargeinductor:theinductorcurrentcanbeconsideredconstant3.2Three-phasecontrolled

(controllable)rectifier3.2.1Three-phasehalf-wavecontrolledrectifier(thebasiccircuitamongthree-phaserectifiers)3.2.2Three-phasebridgefully-controlledrectifier(themostwidelyusedcircuitamongthree-phase

rectifiers)3.2.1Three-phasehalf-wave

controlledrectifierCommon-cathodeconnectionNaturalcommutationpointResistiveload,a=0oResistiveload,a=30oResistiveload,a=60oResistiveload,quantitativeanalysisWhena

30o,loadcurrentidiscontinuous.

Whena>30o,loadcurrentidisdiscontinuous.

(3-18)(3-19)AverageloadcurrentThyristorvoltages(3-20)1-resistorload2-inductorload3-resistor-inductorloadInductiveload,LislargeenoughLoadcurrentidisalwayscontinuous.Thyristorvoltageandcurrents,transformercurrent(3-18)(3-23)(3-24)(3-25)3.2.2Three-phasebridge

fully-controlledrectifierCommon-cathodegroupandcommon-anodegroupofthyristorsNumberingofthe6thyristorsindicatesthetriggersequence.

CircuitdiagramddbacidudVT1VT3VT5VT4VT6VT221TnialoadResistiveload,a=0oResistiveload,a=30oResistiveload,a=60oResistiveload,a=90oInductiveload,a=0oInductiveload,a=30oInductiveload,a=90oPowerElectronics31QuantitativeanalysisAverageoutputvoltageForresistiveload,Whena>60o,loadcurrentidisdiscontinuous.Averageoutputcurrent(loadcurrent)TransformercurrentThyristorvoltageandcurrentSameasthree-phasehalf-waverectifierEMFload,LislargeenoughAllthesameasinductiveloadexceptthecalculationofaverageoutputcurrent(3-26)(3-20)(3-27)(3-28)(3-29)3.3Effectoftransformerleakage

inductanceonrectifiercircuitsInpractical,thetransformerleakageinductancehastobetakenintoaccount.Commutationbetweenthyristorsthuscannothappeninstantly,butwithacommutationprocess.CommutationprocessanalysisCirculatingcurrentikduringcommutationCommutationangleOutputvoltageduringcommutationub-ua=2·LB·dia/dtik:0Idia=Id-ik:Id0ib=ik:0Id(3-30)ReductionofaverageoutputvoltageduetothecommutationprocessCalculationofcommutationangleId,gXB,gFora

90o,a,gQuantitativecalculation(3-31)(3-36)SummaryoftheeffectonrectifiercircuitsConclusionsCommutationprocessactuallyprovidesadditionalworkingstatesofthecircuit.di/dtofthethyristorcurrentisreduced.Theaverageoutputvoltageisreduced.Positivedu/dtNotchingintheACsidevoltage

Single-phasefullwaveSingle-phasebridgeThree-phasehalf-waveThree-phasebridgem-pulserecfifier①②Circuits3.4Capacitor-filtereduncontrolled

(uncontrollable)rectifierEmphasisofprevioussectionsControlledrectifier,inductiveloadUncontrolledrectifier:diodesinsteadofthyristorsWideapplicationsofcapacitor-filtereduncontrolledrectifierAC-DC-ACfrequencyconverterUninterruptiblepowersupplySwitchingpowersupply3.4.1Capacitor-filteredsingle-phaseuncontrolled

rectifier3.4.2Capacitor-filteredthree-phaseuncontrolled

rectifier3.4.1Capacitor-filteredsingle-phase

uncontrolledrectifierSingle-phasebridge,RCload3.4.1Capacitor-filteredsingle-phase

uncontrolledrectifierSingle-phasebridge,RLCload3.4.2Capacitor-filteredthree-phase

uncontrolledrectifierThree-phasebridge,RCload3.4.2Capacitor-filteredthree-phase

uncontrolledrectifierThree-phasebridge,RCloadWaveformwhenwRC

1.732a）wRC=

b）wRC<

3.4.2Capacitor-filteredthree-phase

uncontrolledrectifierThree-phasebridge,RLCload3.5HarmonicsandpowerfactorofrectifiercircuitsOriginatingofharmonicsandpowerfactorissuesinrectifiercircuitsHarmonics:workinginswitchingstates—nonlinearPowerfactor:firingdelayanglecausesphasedelayHarmfuleffectsofharmonicsandlowpowerfactorStandardstolimitharmonicsandpowerfactor3.5.1Basicconceptsofharmonicsandreactivepower3.5.2ACsideharmonicsandpowerfactorof

controlledrectifierswithinductiveload3.5.3ACsideharmonicsandpowerfactorof

capacitor-filtereduncontrolledrectifiers3.5.4HarmonicanalysisofoutputvoltageandcurrentForpuresinusoidalwaveformForperiodicnon-sinusoidalwaveformorwhereFundamentalcomponentHarmoniccomponents(harmonics)3.5.1Basicconceptsofharmonics

andreactivepower(3-54)(3-55)(3-56)Harmonics-relatedspecificationsTakecurrentharmonicsasexamplesContentofnthharmonicsInistheeffective(RMS)valueofnthharmonics.I1istheeffective(RMS)valueoffundamentalcomponent.Totalharmonicdistortion

Ihisthetotaleffective(RMS)valueofalltheharmoniccomponents.(3-57)(3-58)DefinitionofpowerandpowerfactorForsinusoidalcircuitsActivepowerReactivepower

Q=UI

sinjApparentpower

S=UIPowerfactor

l=cos

j(3-59)(3-60)(3-61)(3-63)(3-62)(3-64)DefinitionofpowerandpowerfactorFornon-sinusoidalcircuitsActivepowerP=UI1

cosj1PowerfactorDistortionfactor(fundamental-componentfactor)

n=I1/IDisplacementfactor(powerfactoroffundamentalcomponent)l1=cos

1Definitionofreactivepowerisstillindispute.(3-65)(3-66)ReviewofthereactivepowerconceptThereactivepowerQdoesnotleadtonettransmissionofenergybetweenthesourceandload.WhenQ10,thermscurrentandapparentpoweraregreaterthantheminimumamountnecessarytotransmittheaveragepowerP.Inductor:currentlagsvoltageby90°,hencedisplacementfactoriszero.Thealternatestoringandreleasingofenergyinaninductorleadstocurrentflowandnonzeroapparentpower,butP=0.Justasresistorsconsumereal(average)powerP,inductorscanbeviewedasconsumersofreactivepowerQ.Capacitor:currentleadsvoltageby90°,hencedisplacementfactoriszero.CapacitorssupplyreactivepowerQ.Theyareoftenplacedintheutilitypowerdistributionsystemnearinductiveloads.IfQsuppliedbycapacitorisequaltoQconsumedbyinductor,thenthenetcurrent(flowingfromthesourceintothecapacitor-inductive-loadcombination)isinphasewiththevoltage,leadingtounitypowerfactorandminimumrmscurrentmagnitude.PowerElectronics473.5.2ACsideharmonicsandpowerfactorof

controlledrectifierswithinductiveloadSingle-phasebridgefully-controlledrectifierACsidecurrentharmonicsofsingle-phasebridgefully-controlledrectifierwithinductiveloadConclusionsOnlyoddorderharmonicsexistIn

1/nIn/I1=1/nwheren=1,3,5,…(3-72)(3-73)Powerfactorofsingle-phasebridgefully-controlledrectifierwithinductiveloadDistortionfactorDisplacementfactorPowerfactor(3-75)(3-76)(3-77)Three-phasebridgefully-controlledrectifierACsidecurrentharmonicsofthree-phasebridgefully-controlledrectifierwithinductiveloadConclusionsOnly6k

1orderharmonicsexist(kispositiveinteger)In

1/nIn/I1=1/n(3-79)where(3-80)Powerfactorofthree-phasebridgefully-controlledrectifierwithinductiveloadDistortionfactorDisplacementfactorPowerfactor(3-81)(3-82)(3-83)3.5.3ACsideharmonicsandpowerfactorof

capacitor-filtereduncontrolledrectifiersSituationisalittlecomplicatedthanrectifierswithinductiveload.Someconclusionsthatareeasytoremember:Onlyoddorderharmonicsexistinsingle-phasecircuit,andonly6k

1(kispositiveinteger)orderharmonicsexistinthree-phasecircuit.Magnitudeofharmonicsdecreasesasharmonicorderincreases.Harmonicsincreasesandpowerfactordecreasesascapacitorincreases.Harmonicsdecreasesandpowerfactorincreasesasinductorincreases.3.5.4Harmonicanalysisofoutputvoltage

andcurrentwhereOutputvoltageofm-pulserectifierwhena=0o(3-85)(3-86)(3-87)RipplefactorintheoutputvoltageOutputvoltageripplefactorwhereURisthetotalRMSvalueofalltheharmoniccomponentsintheoutputvoltage

andUisthetotalRMSvalueoftheoutputvoltageRipplefactorsforrectifierswithdifferentnumberofpulses(3-88)(3-89)m23612∞gu（%）48.218.274.180.9940Harmonicsintheoutputcurrentwhere(3-92)(3-93)(3-94)(3-95)Conclusionsfora=0oOnlymk(kispositiveinteger)orderharmonicsexistintheoutputvoltageandcurrentofm-pulserectifiersMagnitudeofharmonicsdecreasesasharmonicorderincreaseswhenmisconstant.Theordernumberofthelowestharmonicsincreasesasmincreases.Thecorrespondingmagnitudeofthelowestharmonicsdecreasesaccordingly.Fora10oQuantitativeharmonicanalysisofoutputvoltageandcurrentisverycomplicatedfora10o.Asanexample,

for3-phasebridge

fully-controlledrectifier(3-96)3.6Highpowercontrolledrectifier3.6.1Double-starcontrolledrectifier

3.6.2Connectionofmultiplerectifiers3.6.1Double-starcontrolledrectifierDifferencefrom6-phasehalf-waverectifierCircuitWaveformsWhena=0oEffectofinterphasereactor(inductor,transformer)(3-97)(3-98)Quantitativeanalysiswhena=0o(3-99)(3-100)(3-101)(3-102)Waveforms

whena>0oComparisonwith3-phasehalf-wave

rectifierand3-phasebridgerectifierVoltageoutputcapabilitySameas3-phasehalf-waverectifierHalfof3-phasebridgerectifierCurrentoutputcapabilityTwiceof3-phasehalf-waverectifierTwiceof3-phasebridgerectifierApplicationsLowvoltageandhighcurrentsituations3.6.2ConnectionofmultiplerectifiersElectronicsPowerLargeroutputcurrent:

parallelconnectionConnection

ofmultiplerectifiersToincreasethe

outputcapacityToimprovetheACsidecurrentwaveformandDCsidevoltagewaveformLargeroutputvoltage:

seriesconnectionPhase-shiftconnectionofmultiplerectifiersParallelconnection12-pulserectifierrealizedbyparalleled3-phasebridgerectifiersPhase-shiftconnectionofmultiplerectifiers12-pulserectifierrealizedbyseries3-phasebridgerectifiersSeriesconnectionVoltageAverageoutputvoltageParallelconnection:

Seriesconnection:OutputvoltageharmonicsOnly12mharmonicsexistInput(ACside)currentharmonicsOnly12k±1harmonicsexistConnectionofmore3-phasebridgerectifiersThree:18-pulserectifier(20ophasedifference)Four:24-pulserectifier(15ophasedifference)Quantitativeanalysisof12-pulserectifierSequentialcontrolofmultiple

series-connectedrectifiersCircuitandwaveformsofseries-connectedthreesingle-phasebridgerectifiers3.7InvertermodeoperationofrectifiersReviewofDCgenerator-motorsystemshouldbeavoid