2023学年完整公开课版Principle of DC Converter

PrincipleofDCConverterContents1.Basicconcepts2.Operatingprincipleof6-pulsatingrectifier3.Operatingprincipleof6-pulsatingInverter4.Lossofpulseorcommutationfailure2DifferencebetweenACandDC3AC：Thedirectionandsizeofvoltageandcurrentchangeperiodicallywithtime,andthewaveformissinusoidal.DC：Thedirectionofvoltageandcurrentdoesnotchangeperiodicallywithtime,andthemagnitudeisnotfixed.Theconceptofcommutation4Rectifier-ConvertingACtoDCthroughacommutationvalve(rectifier).AC→DCInverter-Convertingdirectcurrenttoalternatingcurrentthroughacommutationvalve(inverter).DC→AC5Cathode(K)Anode(A)Controlpole(G)CathodeonthefrontAnodeonthebackControlpoleConverterequipment-thyristorBasiccharacteristicsofthyristors6Basiccharacteristics：Unidirectionalconnectivity，Itcanblockarangeofforwardandreversevoltageswhennotconducting，Afterturnon,thevoltageofthethyristorisalmostzero.TheconditionsofThyristorturnon

：

1.

Theanodevoltagemustbehigherthanthecathodevoltage,thevalvevoltageispositive；2.

Addingtherequiredtriggerpulsetothecontrolpole。Basiccharacteristicsofthyristors7TheconditionsofThyristorturnoff：

1.

Thecurrentflowingthroughtheconvertervalveisreducedtozero；2.

Thevalvevoltageiszeroornegativeforaperiodoftime。Thyristorcharacteristiccurve89Triggerangle：Fromthetimewhenthyristorbeginstowithstandforwardvoltagetothetimewhentriggerpulseisaddedtoit,thecorrespondingelectricalangle（α）isobtained.。Commutationangle：Theelectricalanglecorrespondingtothetimespentinthecommutationprocessisexpressedinμ.

ConverterValveAngleConcept10Valvevoltage：Thevoltagebetweenanodeandcathodeofbridgearmofconvertervalve。Whentheconvertervalveisturnedon,thevalvevoltageisalmostzero.Terminalvoltage：Thevoltageoftheearthtothecommoncathodeandthecommonanodeoftheconvertervalve.VoltageConceptofConverterValve11DCvoltage：DifferencebetweenCommonCathodeandCommonAnodeExtremeVoltageofConverterValve。UD＝UM-UNVoltageConceptofConverterValveContents1.Basicconcepts2.Operatingprincipleof6-pulsatingrectifier3.Operatingprincipleof6-pulsatingInverter4.Lossofpulseorcommutationfailure1213135462ibMNeaLcABCLd+ud

_IdiciaLcLcebecoEquivalentCircuitDiagramof6-PulseRectifier14Triggersequenceof6-pulserectifier：

V6→V1→V2→V3→V4→V5→V6→V1

Triggerintervalofeachvalve：60°

turnoncycleofeachvalve：120°V1V3V5V4V6V2UAUBUCThesequenceoftriggerandcommutationofrectifier15Phasevoltage:（1）Linevoltage:（2）Naturalcommutationpoint：ntersectionPointofPowerSupplyPhaseVoltagePowersupplyelectromotiveforce16AnalysisoftheFirstHalfBridgeV1、V2turnon

V2、V3

turnon

V1、V2turnon

→135462ibMNeaLcABCLd+ud

_IdiciaLcLcebecoOperatingprincipleof6-pulsatingrectifierα=0，μ=017

V1、V2turnon

voltage：

after

ωt=c3∵p3trigger，meanwhile∴V3turnon,V1turnoff135462ibMNeaLcABCLd+ud

_IdiciaLcLcebecoAnalysiscoftheFirstHalfBridge18V2、V3turn

onVoltage

、Valvecurrent、Phasecurrent、DCCurrentWaveform135462ibMNeaLcABCLd+ud

_IdiciaLcLcebecoAnalysiscoftheFirstHalfBridge19

V2、V3turnon

V3、V4turnon→135462ibMNeaLcABCLd+ud

_IdiciaLcLcebecoafter

ωt=c4∵p4trigger，meanwhile∴V4turnon,V2turnoffAnalysisofLowerHalfBridge20135462ibMNeaLcABCLd+ud

_IdiciaLcLcebecoV3、V4

turnonAnalysisofLowerHalfBridgeVoltage

、Valvecurrent、Phasecurrent

、

DCCurrentWaveform21ValidValueofVoltageofPowerLine（3）（4）Idealno-loadDCvoltageAverageValueofRectifierVoltageα=0，μ=022Trigger(Delay)Angle/DelayAngle/IgnitionAngle（）：Thetimefromthenaturalcommutationpointtothecontrolpoleofthethyristortotriggerthepulseexpressedbytheelectricalangle.AnalysiscoftheFirstHalfBridge

V1、V2turnon

V2、V3turnon→

V1、V2turnon

V2、V3turnonSameaswithouttriggerdelayandcommutationangleOperatingprincipleof6-pulsatingrectifierα>0，μ=023

when

ωt=c3～p3

∵p3nottrigger，although135462ibMNeaLcABCLd+ud

_IdiciaLcLcebeco∴V3

notturnonα>0，μ=0AnalysiscoftheFirstHalfBridge24

ωt>p3

∵p3trigger，meanwhile135462ibMNeaLcABCLd+ud

_IdiciaLcLcebeco∴V3turnon,V1turnoffAnalysiscoftheFirstHalfBridgeα>0，μ=0Voltage、Valvecurrent、Phasecurrent

、DCCurrentWaveform25

after

ωt>p4

∵p4trigger，meanwhile∴V4turnon,V2turnoff135462ibMNeaLcABCLd+ud

_IdiciaLcLcebecoAnalysisofLowerHalfBridgeα>0，μ=0Voltage

、Valvecurrent、Phasecurrent

、

DCCurrentWaveform26（5）Characteristic：increase

,

decrease.AverageValueofRectifierVoltageα>0，μ=0WorkingPrincipleofSingleBridge27Settheshortcircuitcurrenttoik135462ibMNeaLcABCLd+ud

_IdiciaLcLcebecoikα>0，μ>0WorkingPrincipleofSingleBridge28

Commutationessence：

Commutationisashort-timetwo-phaseshortcircuitinACsystem.ThecommutationiscarriedoutbyshortcircuitcurrentprovidedbyACpowersupply.Theprocessoftransferringcurrentfromonethyristortoanotherthyristorinthesamehalfbridge.Commutationcurrent：Shortcircuitcurrentduringcommutationα>0，μ>0WorkingPrincipleofSingleBridge29

Commutationvoltage：ACsupplyvoltageprovidingcommutationcurrentCommutationimpedance：Equivalentimpedancebetweenneutralpointofeachphasepowersupplyandbridgearmα>0，μ>0WorkingPrincipleofSingleBridge30135462ibMNeaLcABCLd+ud

_IdiciaLcLcebecoikVoltage、Valvecurrent、Phasecurrent

、

DCCurrentWaveform31

V1、V2turnon

V1、V2、V3turnon

V2、V3

turnon→→

V1、V2turnon

V2、V3

turnonSameastriggerdelayandcommutationangle

when

ωt=α～α＋μ，VoltageAnalysisoftheFirstHalfBridgeContents1.Basicconcepts2.Operatingprincipleof6-pulsatingrectifier3.Operatingprincipleof6-pulsatingInverter4.Lossofpulseorcommutationfailure3233LeadAngle/TriggerLeadAngle（）：Thetimelaggingbehindthenaturalcommutationpoint180degreestothetimewhenthecontrolpulseisemittedisindicatedbytheelectricalangle.ExtinguishingAngle/Turn-offOverheadAngle（）：Thetimewhenthepositivevoltageontheextinguishingvalveisnegativeexpressedbytheelectricalangle.

meanwhileSuitableconditions：Nouninterpretation34α=TriggerDelayAngleμ=Overlappingangleorcommutationangle

δ=Arcextinguishingdelayangle=α+μβ=Triggeringleadangle=π-α=γ+μγ=LeadAngleofExtinguishingArc=π-δNouninterpretation35ConnectingwithACSystem-ActiveInverter；ConnecttoasufficientlylargeDCpowersupply；Ithasthecontrolabilitytoadjustαintherangeof90°~180°.eaebecicLcibia+

udi－A4MN12563BCoLcLcIdLdikNecessaryConditionsforInverterOperationTheWayofInverterConnectingtoHVDCSystem36ebMNIdIdLceaeceaebeciaicLc135462ABCibicibiaLdLd+

Udr

－+

Udi

－A4MN12563BCOperatingprincipleof6-pulsatingInverter37

ωt∈(C3,α)/V1、V2turnonAnalysisofLowerHalfBridge

V1、V2turnon

V1、V2、V3turnon

V2、V3turnon

→→eaebecicLcibia+

udi－A4MN12563BCoLcLcIdLdVoltage

、Valvecurrent、Phasecurrent

、

DCCurrentWaveformOperatingprincipleof6-pulsatingInverter38

ωt=α～α＋μ/V1、V2、V3

turnoneaebecicLcibia+

udi－A4MN12563BCoLcLcIdLdikAnalysisofLowerHalfBridge39V1V3V5V4V6V2UAUBUCV1V3V5V4V6V2UAUBUCRUd2RectifiersideInvertersideUd1Ud1>Ud2IDPowerHVDCtransmissionContents1.Basicconcepts2.Operatingprincipleof6-pulsatingrectifier3.Operatingprincipleof6-pulsatingInverter4.Lossofpulseorcommutationfailure40DCNormalWaveform41NormalCurrent42Normaloperationwaveform43311V1V26110V2V3121100V3V42411000V4V548110000V5V633100001V1V6Rectifierside:V3missingmonopulse621546235LossofPulseRecordingatRectifier

Station(ValveInterfaceFault)

4414512345612354661214旁通3脉冲丢失InverterSideLostPulse46OnJuly20,2014,V6wasinadvertentlyturnedon,V3wasinadvertentlyturnedon,V3andV6formedbypasspairs.344556611223T1:V5TriggerT2:V6ErrorTriggerT3:ForwardvoltageonbothsidesofV3,openbymistakewithoutclosingT4:V3V6formsbypasspairsT5:VoltageUAB<0onbothsidesofV1,unabletotriggersuccessfullyT6:V2VoltageSatisfiesConditions,V6toV2commutation,12conductionFengxianStationErrorTrigger47351621,6valvesturnon(2)2,6valvesarereversed,6valvesarenotextinguished(3)1,3valvecommutation,3valveturnon(4)3and6valvesformbypasspairs(5)ACcurrentdecreasesandDCcurrentincreases51642CommutationFailureofInverterStationTHANKYOU49eaebecC1C3C5C1C3C2C6C4C2p2p1p4p3p5p1p6p3p2v2v3v6v1v3v4v5v6v1v2v6v1v5v6v4v5v1v2v2v3v3v4eaceabebaebcecbecaeabea

VoltageWaveformof6-PulseRectifier(α=0、μ=0)50eaebecC1C3C5C1C3C2C6C4C2p2p1p4p3p5p1p6p3p2v2v3v6v1v3v4v5v6v1v2v6v1v5v6v4v5v1v2v2v3v3v4iV1iV2iV3iV5iV4iV6Valvecurrentwaveform(α=0、μ=0)51eaebecC1C3C5C1C3C2C6C4C2p2p1p4p3p5p1p6p3p2v2v3v6v1v3v4v5v6v1v2v6v1v5v6v4v5v1v2v2v3v3v4iaibic

PhaseCurrentWaveform(α=0、μ=0)52p2p1p4p3p5p1p6p3p2v2v3v6v1v3v4v5v6v1v2v6v1v5v6v4v5v1v2v2v3v3v4eaebecC1C3C5C1C3C2C6C4C2Id+13513Id-246246

DCCurrentWaveform(α=0、μ=0)53eaebecC1C3C5C1C3C2C6C4C2eaebeceav2v3v6v1v3v4v5v6v1v2v6v1v5v6v4v5v1v2v2v3v3v4p2p1p4p3p5p1p6p3p2p5p4eaceabebaebcecbecaeaceabebcVoltageWaveformof6-PulseRectifier(α>0、μ=0)54eaebecC1C3C5C1C3C2C6C4C2eaebeceav2v3v6v1v3v4v5v6v1v2v6v1v5v6v4v5v1v2v2v3v3v4p2p1p4p3p5p1p6p3p2p5p4iV1iV2iV3iV5iV4iV6

Valvecurrentwaveform(α>0、μ=0)55eaebecC1C3C5C1C3C2C6C4C2eaebeceav2v3v6v1v3v4v5v6v1v2v6v1v5v6v4v5v1v2v2v3v3v4p2p1p4p3p5p1p6p3p2p5p4iaibic

PhaseCurrentWaveform(α>0、μ=0)56eaebecC1C3C5C1C3C2C6C4C2eaebeceav2v3v6v1v3v4v5v6v1v2v6v1v5v6v4v5v1v2v2v3v3v4p2p1p4p3p5p1p6p3p2p5p4Id+13513Id-246246

DCCurrentWaveform(α>0、μ=0)57pα＝0pα＝300pα＝600pα＝900pα＝1200pα＝1500pα＝1800

Converterud(α=0°~180°)58eaebeceaebecC1C2C3C4C5C6C1C1C2C3C4C5C6561566126112312234233453445645561566126112312234233453445645p1p2p3p4p5p6p1p2p3p4p5p6eaceabebaebcecbecaeaceabebaebcecbeca

VoltageWaveformof6-PulseRectifier(α>0、μ>0)59eaebeceaebecC1C2C3C4C5C6C1C1C2C3C4C5C6561566126112312234233453445645561566126112312234233453445645p1p2p3p4p5p6p1p2p3p4p5p6Valvecurrentwaveform(α>0、μ>0)60eaebeceaebecC1C2C3C4C5C6C1C1C2C3C4C5C6561566126112312234233453445645561566126112312234233453445645p1p2p3p4p5p6p1p2p3p4p5p6PhaseCurrentWaveform(α>0、μ>0)

DCCurrentWaveform(α>0、μ>0)61eaebeceaebecC1C2C3C4C5C6C1C1C2C3C4C5C6561566126112312234233453445645561566126112312234233453445645p1p2p3p4p5p6p1p2p3p4p5p6iV1iV3iV5iV1iV3iV5iV2iV4iV6iV2iV4iV6626126145634556112323434545656161212323445566112233445561223

p4

p3

p6

p1

p2

p5

p1.

p2

P4

p3

p6

p5C6C4C4C2C3