25T客車逆變器的工作原理ZHENGZHOURAILWAYVOCATIONAL&TECHNICALCOLLEGE客車電氣裝置/BUSELECTRICALINSTALLATIONSpeaker主講人Zhangjia張嘉一、結構組成ThestructureandcompositionoftheinverterTFG23逆變器箱的組成、參數與原理TGF23系列型25T客車逆變器箱適用于具有DC6O0V供電電壓的動車組、車輛或其它具有相應供電制式及功率等級的設備。TGF23series25TpassengertraininverterboxissuitableforEMU,vehiclesorotherequipmentwithcorrespondingpowersupplysystemandpowerlevelwithDC600Vpowersupplyvoltage.該逆變器箱包括2臺35kVA的逆變電源裝置和1臺不小于10kVA的變壓器。Theinverterboxincludestwo35kVAinverterpowersupplydevicesandonetransformernotlessthan10kVA.逆變電源為空調、電加熱器以及其他車載交流380V用電設備供電，變壓器為AC220V用電設備供電。Theinverterpowersuppliespowerforairconditioners,electricheatersandotherin-trainAC380Velectricalequipment,andthetransformersuppliespowerforAC220Velectricalequipment.

TFG23逆變器箱的組成、參數與原理TGF23系列包括提供給長客廠的TGP23型及TGF23D型(高寒高包車用)、提供給四方廠的TGF23A型(軟硬車用)、TGF23B(高包車用)、TGF23C(餐車用)。TGF23seriesincludetheTGP23andTGF23DmodelsprovidedtoChangchunRailwayVehiclesCo.,Ltd.andtheTGF23BandTGF23CmodelsprovidedtoQingdaoSifangLocomotive&RollingStockCo.,Ltd.TGF23D型逆變器箱與其余四種的主要區別在于其三相變壓器容量為15kVA，其他為12KVA。ThemaindifferencebetweenTGF23Dinverterboxandtheotherfourtypesisthatitsthree-phasetransformercapacityis15kVA,whileothersare12KVA.其余四種之間的主要區別體現在柜體吊裝和出線規劃方面的差異。Themaindifferencesbetweenthefourtypesarereflectedincabinethoistingandoutgoinglineplanning.TFG23逆變器箱的組成、參數與原理二、主要技術參數Maintechnicalparameters

TFG23逆變器箱的組成、參數與原理三、25T–2×35kVA＋12kVA逆變器工作原理Workingprincipleofthe25T–2×35kVA＋12kVAinverter（一）主電路的組成Compositionofthemaincircuit1．輸入輸出隔離電路Inputandoutputisolatedcircuit

圖中的KM1、KM3電磁接觸器，其主要功能是在逆變器、輸入電路或輸出負載發生故障時實施隔離，防止故障擴散。TheKM1andKM3electromagneticcontactorsinthefigurearemainlyusedtoisolateandpreventfaultpropagationintheeventofinverter,inputcircuit,oroutputloadfaults.TFG23逆變器箱的組成、參數與原理2.中間支撐電路Intermediatesupportcircuit主要由濾波電容C1、C2組成。IntermediatesupportcircuitmainlyconsistsoffiltercapacitorsC1,C2.其主要功能是濾平輸入電路的電壓紋波，當負載變化時，使直流電壓平穩。由于逆變器功率較大，因此濾波電容的容量較大，一般使用電解電容。Itsmainfunctionistofilterthevoltagerippleoftheinputcircuit.Whentheloadchanges,itcanmaketheDCvoltagestabilized.Duetothelargepoweroftheinverter,thefiltercapacitorhasalargecapacity.Therefore,anelectrolyticcapacitorisusuallyused.R1和R2的另一個作用是在逆變器停止工作時，將電容上的電壓放掉。AnotherroleofR1andR2istoreleasethevoltageonthecapacitorwhentheinverterstopsworking.但由于電解電容的電壓等級限制（一般最高工作電壓為450V），需要兩個電容串聯后再并聯。Butduetothevoltagelevellimitofelectrolyticcapacitors,twocapacitorsneedtobeconnectedinseriesandthenconnectedinparallel.由于電容自身參數的離散，使得串聯的兩個電容電壓無法完全一致，因此采用電容兩端并聯均壓電阻的方法，如圖中的R1和R2。Duetothedifferentparametersofthecapacitor,thevoltagesofthetwocapacitorsconnectedinseriescannotbeexactlythesame.Therefore,themethodofconnectingvoltageequalizingresistorsinparallelatbothendsofthecapacitorisused,suchasR1andR2inthefigure.TFG23逆變器箱的組成、參數與原理3.緩沖電路Snubbercircuit

由R0和KM2組成。ThesnubbercircuitconsistsofR0andKM2.電容的特性是電壓不能突變，因此在合閘瞬間，電容的電壓很低，基本可以認為瞬間短路，因此對電源造成很大的沖擊電流，這個電流足以使保護熔斷器熔斷，因此逆變器電路一般都有輸入緩沖電路。Thecharacteristicofcapacitanceisthatthevoltagecannotchangesuddenly,sothatatthemomentofclosing,thevoltageofthecapacitorisverylow,whichcanbasicallybeconsideredasaninstantshortcircuit.Thenalargeinrushcurrentiscausedtothepowersupply,whichisenoughtoblowtheprotectivefuse.Therefore,invertercircuitsusuallyhaveinputsnubbercircuit.其工作原理為：Theprincipleoftheinputsnubbercircuitasfollows：

在輸入端施加電壓時，先通過緩沖電阻R0對電容充電，當電容電壓充到一定值時（比如540V），KM2吸合，將R0短路。Whenavoltageisappliedtotheinput,thecapacitorisfirstchargedthroughthesnubberresistorR0,andwhenthecapacitorvoltageischargedtoacertainvalue,KM2pullsinandR0isshort-circuited.只有電阻R0短路后，三相逆變電路才能啟動工作。OnlyaftertheresistorR0isshort-circuited,thethree-phaseinvertercircuitcanstarttowork.

TFG23逆變器箱的組成、參數與原理4．橋式三相逆變電路Bridgethree-phaseinvertercircuit由V1~V6組成的橋式三相逆變主電路是逆變器的核心電路，目前大部分逆變器采用IGBT和IPM作為開關器件。Thebridge-typethree-phaseinvertermaincircuitcomposedofV1toV6isthecorecircuitoftheinverter.Atpresent,mostinvertersuseIGBTandIPMasswitchingdevices.TFG23逆變器箱的組成、參數與原理5．交流濾波電路ACfiltercircuit由L1～L3和C1～C3組成，主要是將逆變器輸出的PWM波變成準正弦波。ACfiltercircuitconsistsofL1toL3andC1toC3.ItmainlyconvertsthePWMwaveoutputbytheinverterintoaquasi-sinewave.早期的逆變器輸出波形PWM波，諧波含量高，很多負載無法適應。EarlyinvertersoutputPWMwaveshavehighharmoniccontent,somanyloadscannotbeconnected.根據鐵路新的技術條件要求，25T客車使用的逆變器輸出為正弦波，由于驅動和保護技術的不斷完善，使逆變器的調制頻率提高，最高可達到6k～8k，因而濾波電感和電容的體積并不太大。Accordingtothenewrequirementsoftherailway,theoutputoftheinverterusedinthe25Tpassengertrainisasinewave.Thecontinuousimprovementofdriveandprotectiontechnologyhasincreasedthemodulationfrequencyoftheinverter,upto6kto8k,sothatthevolumeofthewaveinductorandcapacitorisnottoolarge.導通順三相逆變器的主電路如圖所示Themaincircuitofthethree-phaseinverterisshowninthefigure.圖中，輸入端為A、B，輸出為U、V、W，右上角為V1～V6的導通順序，陰影部分為各個IGBT的導通時間，每一格的時間為л/3。Inthefigure,theinputterminalsareA,B,andtheoutputterminalsareU,V,W.TheupperrightcorneristheconductionsequenceofV1~V6,theshadedpartistheon-timeofeachIGBTandthetimeofeachgridisл/3.根據各IGBT的導通順序，可以繪出U、V、W的線電壓波形。AccordingtotheconductionsequenceofeachIGBT,thelinevoltagewaveformsofU,V,andWcanbedrawn.三相線電壓之間的相位差為2л/3，幅值與直流電壓Ud相等，只要按照一定的順序控制6個逆變管的導通與截止，就可以把直流電逆變成三相交流電。Thephasedifferencebetweenthethree-phaselinevoltageis2л/3,andtheamplitudeisidenticaltotheDCvoltageUd.Aslongasthesixinvertertubesareturnedonandoffinacertainorder,thedirectcurrentcanbeconvertedintoathree-phasealternatingcurrent.導通順序T1、T2時間內，V1、V4同時導通，U為+，V為-，UUV為+且Um=Ud。DuringT1andT2time,V1andV4conductsimultaneously,Uis+,Vis-,UUVis+andUm=Ud.根據各IGBT的導通順序，可以繪出U、V、W的線電壓波形。AccordingtotheconductionsequenceofeachIGBT,thelinevoltagewaveformsofU,V,andWcanbedrawn.(1)(2)每一格時間為π/3導通順序T3、T4時間內，V3、V6同時導通，V為+，W為-，UVW為+且Um=Ud。DuringT3andT4time,V3andV6conductsimultaneously,Vis+,Wis-,UVWis+andUm=Ud.T6、T1時間內，V4、V5同時導通，V為-，W為+，UVW為-且Um=-Ud。、DuringT6andT1time,V4andV5conductsimultaneously,Vis-,Wis+,UVWis-andUm=-U