3.3变压器漏感对整流电路的影响 The influence of transformer leakage inductance on rectifier circuit中英版

Powerelectronicstechnology电力电子技术3.3Influenceoftransformerleakageinductanceonrectifiercircuit3.3变压器漏感对整流电路的影响Item3Rectifiercircuit项目三整流电路TeachingResourcesDatabaseof

NationalVocationalEducationPowerSupplyTechnologyBilingualcourses3.3Influenceoftransformerleakageinductanceonrectifiercircuit

变压器漏感对整流电路的影响前面分析整流电路时，均来考虑包括变压器漏感在内的交流侧电感的影响，认为换相是瞬时完成的。Inthepreviousanalysisoftherectifiercircuit,theinfluenceofACsideinductanceincludingtransformerleakageinductancewasconsidered,andthecommutationwasconsideredtobeinstantaneous.但实际上变压器绕组总有漏感，该漏感可用一个集中的电感表示，并将其折算到变压器二次侧。Infact,thereisalwaysleakageinductanceinthetransformerwindings,whichcanbeexpressedbyaconcentratedinductanceandconvertedtothesecondarysideofthetransformer.由于电感对电流的变化起阻碍作用，电感电流不能突变，因此换相过程不能瞬间完成，而是会持续一段时间。Becausetheinductancehindersthechangeofthecurrent,theinductancecurrentcannotbeabrupt,sothecommutationprocesscannotbecompletedinstantly,butwillcontinueforaperiodoftime.

实际工作中，整流变压器存在漏抗，晶闸管之间的换流不能瞬时完成，会出现参与换流的两个晶闸管同时导通的现象，同时导通的时间对应的电角度称为换相重叠角γ。Inpracticalwork,therectifiertransformerhasleakagereactance,andtheconverterbetweenthethyristorscannotbecompletedinstant.Therewillbethephenomenonthatthetwothyristorsparticipatingintheconverterconductatthesametime,andtheelectricalanglecorrespondingtotheconductiontimeiscalledcommutationoverlapangleγ.1、换相重叠角γCommutationoverlapangleYLl为变压器的每相绕组折合到二次侧的漏抗Llistheleakagereactanceofeachphasewindingofthetransformerconvertedtothesecondaryside

图1考虑变压器的漏抗后相控整流电路的等效电路及输出电压电流的波形Figure1Theequivalentcircuitandthewaveformofoutputvoltageandcurrentofthephase-controlledrectifiercircuitafterleakagereactanceofthetransformerareconsidered

3.3Influenceoftransformerleakageinductanceonrectifiercircuit

变压器漏感对整流电路的影响

当ωt１时刻触发Ｔ２时，Ｂ相电流不能瞬时上升到Ｉd值，Ａ相电流不能瞬时下降到零，电流换相需要时间tγ，换流重叠角所对应的时间为tγ=γ/ω。在重叠角期间，Ｔ１、Ｔ２同时导通，产生一个虚拟电流Ik

，Whenωt１triggersＴ２,theBphasecurrentcannotrisetotheIdvalue,Aphasecurrentcannotfalltozero,thecurrentcommutationrequirestimetγ，thecorrespondingtimefortheoverlapAngleofthecommutationistγ=γ/ω.Duringtheoverlapangle,T1andT2simultaneouslyturnon,producingavirtualcurrentIk,2、工作过程WorkingprocessLl为变压器的每相绕组折合到二次侧的漏抗Llistheleakagereactanceofeachphasewindingofthetransformerconvertedtothesecondaryside

3.3Influenceoftransformerleakageinductanceonrectifiercircuit

变压器漏感对整流电路的影响图1考虑变压器的漏抗后相控整流电路的等效电路及输出电压电流的波形Figure1Theequivalentcircuitandthewaveformofoutputvoltageandcurrentofthephase-controlledrectifiercircuitafterleakagereactanceofthetransformerareconsidered

而整流输出电压为Andtherectifieroutputvoltageis由图可知Thefigureshows2、工作过程Workingprocess3.3Influenceoftransformerleakageinductanceonrectifiercircuit

变压器漏感对整流电路的影响图1考虑变压器的漏抗后相控整流电路的等效电路及输出电压电流的波形Figure1Theequivalentcircuitandthewaveformofoutputvoltageandcurrentofthephase-controlledrectifiercircuitafterleakagereactanceofthetransformerareconsidered

在γ期间，直流输出电压比uA或uB都小，使输出电压波形减少了一块阴影面积,降低的电压值为

。Duringγ,theDCoutputvoltageissmallerthaneitherUAorUB,sothattheoutputvoltagewaveformisreducedbyashadowarea,andthereducedvoltagevalueis.式Formula

ud表明：Shows图中的阴影面积大小为：Thesizeoftheshadowareainthefigureis:2、工作过程Workingprocess3.3Influenceoftransformerleakageinductanceonrectifiercircuit

变压器漏感对整流电路的影响图1考虑变压器的漏抗后相控整流电路的等效电路及输出电压电流的波形Figure1Theequivalentcircuitandthewaveformofoutputvoltageandcurrentofthephase-controlledrectifiercircuitafterleakagereactanceofthetransformerareconsidered

图1考虑变压器的漏抗后相控整流电路的等效电路Figure1Theequivalentcircuitofphase-controlledrectifyingcircuitaftertheleakagereactanceofthetransformerisconsidered1）换相压降Uγ

CommutationpressuredropUγ3、参数计算Parametercalculation上式中是变压器每相漏感折合到二次则的漏电抗。Intheaboveformula,theleakagereactanceofthetransformerisconvertedtothesecondaryleakageinductanceperphase.在图2.5.1(a)所示的三相半波可控整流电路中，整流输出电压为3相波形组合（即一周期内换相3次），每个周期内有3个阴影面积，这些阴影面积之和3S除以周期2π，即为换相重叠角期间输出平均电压的减少量，称为换相压降Uγ。

Inthethree-phasehalf-wavecontrollablerectifiercircuitshowninFigure2.5.1(a),therectifieroutputvoltageisathree-phasewaveformcombination(i.e.,threecommutationtimeswithinonecycle),andtherearethreeshadowareasineachcycle.Thesumoftheseshadowareasis3Sdividedbytheperiod2π,whichisthereductionoftheoutputaveragevoltageduringthecommutationoverlapAngle,calledcommutationvoltagedropUγ.

换相压降Uγ正比于负载电流Ｉd，它相当于整流电源增加了一项等效电阻，但这个等效内阻并不消耗有功功率。CommutationvoltagedropUγisproportionaltotheloadcurrentID,whichisequivalenttoaddinganequivalentresistancetotherectifiersupply,butthisequivalentinternalresistancedoesnotconsumeactivepower.

3.3Influenceoftransformerleakageinductanceonrectifiercircuit变压器漏感对整流电路的影响上式表明，当Ll或Id增大时，γ将增大；当α增大时，γ减小。必须指出，如果在负载两端并联续流二极管，将不会出现换流重叠的现象，因为换流过程被续流二极管的存在所改变。

TheaboveequationshowsthatwhenLLorIDincreases,γwillincrease;Asαincreases,γdecreases.Itmustbenotedthatifthecontinuationdiodesareconnectedinparallelatbothendsoftheload,therewillbenooverlapinthecommutationbecausethecommutationprocessisalteredbythepresenceofthecontinuationdiodes.2、换相重叠角γcommutationoverlapangleY图1考虑变压器的漏抗后相控整流电路的等效电路及输出电压电流的波形Theequivalentcircuitandthewaveformofoutputvoltageandcurrentofthephase-controlledrectifiercircuitafterleakagereactanceofthetransformerisconsidered3.3Influenceoftransformerleakageinductanceonrectifiercircuit变压器漏感对整流电路的影响2、换相重叠角γ计算过程Calculationprocessofcommutationoverlapangleγ在图2.5.1(b)中为便于计算，将坐标原移到Ａ、Ｂ相的自然换流点，设Infigure2.5.1(b),fortheconvenienceofcalculation,theoriginalcoordinateismovedtothenaturalcommutationpointofphaseAandphaseB,andlet由式(5.5.1)可得

ItcanbeobtainedfromEquation(5.5.1)将上式两边同乘以ω得Multiplyω

bothsidesofthisequation从电路工作原理可知，当电感Ll中电流从０变到Id时，正好对应ωt从α变到α+γ，将此条件代入式(5.5.5)得Fromtheworkingprincipleofthecircuit,itcanbeseenthatwhenthecurrentintheinductanceLl

changesfrom0toId,itexactlycorrespondstothechangeofωtfromαtoα+γ.ThisconditionissubstitutedintoEquation(5.5.5)toobtain即Namely则换相重叠角为

Thenthecommutationoverlapangleis3.3Influenceoftransformerleakageinductanceonrectifiercircuit变压器漏感对整流电路的影响2、换相重叠角γ的计算过程Calculationprocessofcommutationoverlapangleγ表1各种整流电路换相压降和换相重叠角的计算Table1Calculationofcommutationvoltagedropandcommutationoverlapangleofvariousrectifiercircuits3.3Influenceoftransformerleakageinductanceonrectifiercircuit变压器漏感对整流电路的影响CircuitformSingle-phasefullwaveSinglephasefullyc