外文翻譯電動汽車dcdc電源轉(zhuǎn)換器的原理、建模和控制

外文原文Principle,ModelingandControlofDC-DCConvertorsforEVZHANGCheng-ning,SUNFeng-chun,ZHANGWang(SchoolofVehicleandTransportationEngineering,BeijingInstituteofTechnology,Beijing100081)Abstract:DC-DCconvertorscanconverttheEV’shigh-voltageDCpowersupplyintothelowvoltageDCpowersupply.Inordertodesignanexcellentconvertoronemustbeguidedbytheoryofautomaticcontrol.Theprincipleandthemethodofdesign,modelingandcontrolforDC-DCconvertorsofEVareintroduced.Themethodofthesystem-responsetoaunitstep-functioninputandthefrequency-responsemethodareappliedtoresearchingtheconvertor’smat-hematicsmodelandcontrolcharacteristic.ExperimentsshowthatthedesignedDC-DCconvertor’soutputvoltageprecisionishigh,theantijammingabilityisstrongandtheadjustableperformanceisfastandsmooth.Keywords:EV;DC-DCconvertors;automaticcontrol;mathematicsmodel;BodedrawingCLCnumber:U469-72Documentcode:AGenerallytherearetwopowersuppliesinEV.OneistheDChigh-voltagepowersupplythatisusedbyhighpowerdevicessuchastractionmotorsandairconditionersetc.TheotheristheDClow-voltagepowersupplythatisusuallyusedinsomecontrolcircuitandlow-voltageelectricaldevicessuchastheinst-rumentandlighting.Itsratingvoltageis24Vor12V.Thelow-voltagepowersupplycanbegainedfromthehigh-voltagepowersupplybyaDC-DCconver-tor.Inthispaper,themainperformanceofthedesignedconvertoristhattheinputvoltagerangeisfromDC250VtoDC450V,theoutputvoltageisDC24V,themaximumoutputcurrentisDC20A,andtheoutputprecisionis1%.1PrincipleoftheConvertor1.1TheBlockDiagramoftheDC-DCConvertorTheblockdiagramoftheDC-DCconvertorisshowedinFig.1.ThebatteryseriesprovidetheDChigh-voltageinputUs.Thelow-voltageoutputofthecon-vertorisUo.ThesettingvalueUioftheconvertorisequaltoorisinproportiontothedemandedoutputvoltageUo.Theconvertorisaclosed-loopnegativefeedback-systemwithvoltagefeedback.1.2PowerSwitchCircuitThepowerswitchcircuitwithsemi-bridgemodeisshowedinFig.2.L1andC1constituteaninputfiltertoavoidhigh-frequencyimpulsesflowingbac-kwards.CapacitorsC2andC3constitutethepartial-voltagecircuitwhileresist-ancesR1andR2doso.IGBT1andIGBT2aresemiconductorswitchdevices.C6isaseparationDCcapacitor.T1isatransformerthatreducesthevoltage.L2andC7constituteanoutputfilter.RListheloadresistance.WhenthePWMsignalsinthereversesemi-wavesareinputtedontoIGBT1andIGBT2’scontrolpoles,thecorrespondingDCvoltagecanbeyieldedfromtheconvertor.Fig.2Principlecircuitofpowerswitchwithsemi-bridgemode1.3ControlCircuitThechipSG3525isusedinthePWMcontrolcircuitshowedinFig.3.Vccisthepowervoltageappliedtothechip,itis1V.Abase-voltageof5.1Visyieldedonpin16ofthechipthatispartiallyusedasparametervoltageinputUi.Thechipincludesasawtooth-wavegenerator.RtandCtaretheexternalresis-tanceandcapacitythatdeterminethesawtooth-wave’sfrequency.Pin2ofthechipisapositive-phaseinputport.VoltageinputUiisputtedtotheport,hereUi=2.5V.Pin1ofthechipisthenegative-phaseinputportwherethefeedbackvoltageisinputted.Pin9ofthechipistheoutputendoftheinsideamplifierofthechip.Theproperresistanceandcapacitorareconnectedbetweenthepin1andpin9torealizecompensationoftheDC-DCconvertor.C8istheintegralcapacitor.Theintegralcompensatorisadoptedasthesystem-compensationofthesystem.ThePWMimpulsesareyieldedfrompin11andpin14ofthechip.WhenthePWMcontrolcircuitoperatesnormally,Uionthepin2andUbonthepin1shouldbebalanced.WhenUbisnotequaltoUi,thePWMwidthcanbeautomaticallyadjustedbythePWMcontrolcircuittomakeUbequaltoUi.Bythiswaywecancontroltheoutputvoltageoftheconvertor.Fig.3TheconnectioncircuitforthePWMcontrolchipSG35251.4DriveCircuitThedrivecircuitofIGBTusuallyadoptsapulse-transformeroranopto-couplertoisolatethepowercircuitfromthecontrolcircuit.Anindividualpowersupplyisneededifanopto-couplerisused,whichincreasesthecomplexityofthesystem.Sotheisolation-circuitadoptsapulse-transformershowedinFig.4.TransistorsBG1andBG2inFig.4composeacomplementationpoweramplificationcircuit.T2isthepulse-transformerthatisolatesthepowercircuitfromthecontrolcircuit.R5andC8composetheaccelerationcircuit.ThediodeD6eliminatesnegativeimpulses.ThediodeD7andtransistorBG3composetherapiddischargecircuitofthedistributingcapacitoratthecontrolpoleofIGBT.Fig.4PrinciplecircuitforIGBTdrive2ModelingandControl2.1ModelingTheDC-DCconvertorisavoltagenegativefeedback-system.Aimingtoobtainthebetterdynamicandstaticcharacteristicwemustmodelandanalyseitintheory.AccordingtoRef.[1],DC-DCconvertorsaretheapproximatesecond-ordersystems.Inordertoobtainaccurateparameters,themethodofthesystem-2.1.1MeasuringtheOpen-LoopSystem’sResponsetoaUnitStep-FunctionInputTheblockdiagramformeasuringisshowninFig.5.Theconcretemethodisdescribedasfollows:①Thevoltagefeedbacksignaliscutoff;②ThesettingvalueofthechipSG3525adoptsthemiddlingvalueUi0tomakethewidthofanimpulsebeabout0.5T;③Ui0issuperimposedwithdUithatiscomposedbypositiveandnegativerectanglewaveimpulses.TheamplitudeofdUiistakentobeequalto0.2Ui0.ItshouldmakedUobeeasytobeobservedtoselecttherectanglewavefrequency,adoptingf1=400Hz;④TheoutputwaveformofUo(=Uo0+dUo)isshowninFig.6.AsshowninFig.6whenf1=400Hz,periodT=2.5ms(5grills),thetimeforthemaximumvoltagevalueisabout0.2grills.dUo’sstablevoltageamplitudeis-grills.Peakovershootis1grill.Everygrillintheverticaldirectionrepresents5V.Bythiswaythedataofsystem-responsetoaunitstep-functioninputcanbeobtainedasfollows:peaktimetp=0.1ms;peakovershootσp=1/2=50%;outputandinput’sincrementalratioK0=dUo/dUi=10/1=10.Fig.5Themeasuringblockdiagramoftheopen-loopsystemFig.6Thesystem-responsetoaunitstep-functioninput2.1.2DeterminingtheOpen-LoopTransferFunctionAccordingtoRefs.[2,3],wehavethedampingratioξ,undampednaturalfrequencyωnandtransferfunctionofcontrolledobjectGp(s)asfollows:InordertoensurethatwhentheoutputvoltageUo=24Vthefeedbackvoltagetopin1oftheSG3525is2.5VtobalancetheinputvoltageUi=2.5V,wetakethefeedbackandmeasuringfactorasKb=Ub/Uo=-15/-4=01104.(4)2.2DesignofthePIDRegulator2.2.1ThePrincipleSchemeandTransferFunctionofthePIDRegulatorToresistthedisturbanceofthepowersupplyvoltageandloadcurrenttotheDC-DCconvertorsoastoimprovecontrolprecision,anintegralcompensatorisadopted.TheprincipleschemeoftheintegralcompensatorisshowninFig.7.Fig.7TheprincipleschemeoftheintegralcompensatorItstransferfunctionisGc(s)=Ki/s=1/(RCs).(5)InFig.7andEq.(5),R=10kΩ,C=0.1μF,Ki=1/(RC)=1/(10×103×011×10-6)=100TheBodeDrawingoftheSystemOpen-LoopTransferFunctionThesystemopen-looptransferfunctionistheproductofthecontrolledobject’s,feedbackandmeasuringcircuit’sandintegralcompensator’stransferfunctions.WehaveG(s)=Gc(s)Gp(s)Gb(s)=ThesystemBodedrawingisshowninFig.8fromEq.(6).Thecurves①and④arerespectivelythelogarithmicgain-frequencycharacteristic,logarithmicphase-frequencycharacteristicofcontrolledobjectGp(s).Thecurves②and⑤arerespectivelythelogarithmicgain-frequencycharacteristic,logarithmicphase-frequencycharacteristicofthefeedbackandmeasuringcircuitjointtheintegralcompensator.Thecurves③and⑥arerespectivelythelogarithmicgain-frequencycharacteristicandlogarithmicphase-frequencycharacteristicofthecompensatedopen-loopsystem.ByFig.8weknowthatthesystemisI-modelsystem.Whentheinputdoesn’tchange,thereisn’tsteady-stateerror.Itsoriginalphase-marginfrequencyωc=1016rad/s,phasemarginγ=89.21°,sotheadjustableperformanceofthesystemisfastandsmooth.Fig.8TheBodedrawingofthesystemopen2looptransferfunction3TheResultandConclusionofExperimentWhentheloadresistanceRL=1.2Ω,theexperimentdataofUs,Is,Uo,Io,η(ηisefficiencyoftheconvertor)areshowninTab.1.WhentheloadresistanceRL=2.4Ω,theexperimentdataofUs,Is,Uo,Io,ηareshowninTab.2.4Conclusions①Becausetheintegralcompensatorisadopted,theoutputvoltageUooftheconvertorhasquitehighprecisioneveniftheinputpowervoltageandtheloadchanges.②Thewidthoftheimpulsesisadjustedautomaticallyintheconvertortorealizeconstantoutputvoltagevalue.Withtheincreaseoftheinputvoltagethewidthoftheimpulsesturnnarrow,theconvertor’sefficiencydrops.IntheprocessofdesigningaDC-DCconvertor,wemustdiminishtheadjustablerangeoftheimpulsewidthandmaketheimpulsewidthwiderwhentheconvertoroperates.③Thereasonablevalueoftheresistanceandcapacitorinthefeedbackcircuitmustbeselectedsothatthefeedback-systemhasenoughgainmarginandphasemarginthatcanguaranteethecontrol-systemtobeadjustedsmoothly.References:[1]CaiXuansan,GongShaowen.High-frequencyelectronics(inChinese)[M].Beijing:SciencePress,1994.232-246.[2]ZhangWang,WangShiliu.Automaticcontrolprinciple(inChinese)[M].Beijing:BeijingInstituteofTechnologyPublishingHouse,1994.71-72.[3]D’AzzoJJ.Linearcontrolsystemanalysisanddesign[M].SanFrancisco:McGraw-HillBookCompany,1981.83-92.電動汽車DC-DC電源轉(zhuǎn)換器的原理、建模和控制張承寧,孫逢春,張旺(北京理工大學(xué)車輛與交通工程學(xué)院,北京100081)摘要：為了設(shè)計出在電動汽車上把高壓直流電源變換成低壓直流電源的高品質(zhì)DC-DC變換器,采用自動控制理論進(jìn)行指導(dǎo).介紹電動汽車DC-DC變換器原理和設(shè)計,建模與控制方法.應(yīng)用階躍響應(yīng)法、頻率法研究其數(shù)學(xué)模型和控制特性,并且進(jìn)行分析和計算.實驗結(jié)果表明,用這種方法所研制的電動汽車DC-DC變換器輸出電壓精度高,抗干擾能力強(qiáng),調(diào)節(jié)特性快速、平穩(wěn).關(guān)鍵詞：電動汽車;DC-DC變換器;自動控制;數(shù)學(xué)模型;Bode圖中圖分類號U469172文獻(xiàn)標(biāo)識碼A通常有兩種電源電動汽車。一個是直流高壓電源采用高功率設(shè)備,如牽引電機(jī)和空調(diào)等。另一個是低壓直流電源,通常被用在一些控制電路和低壓電器設(shè)備,如儀表和照明。它的額定電壓24V或12V低壓供電,可由高電壓供電直流-直流變換器得到在本文中,主要性能設(shè)計的是輸入電壓轉(zhuǎn)換器,范圍從直流250V到直流450V,輸出直流電壓24V、最大輸出電流是直流20A,輸出精度為1%。1變換器原理1·1直流-直流變換器的原理框圖直流-直流轉(zhuǎn)換器的原理框圖如圖1所示，電池組提供直流高壓輸入Us，低壓變頻器的輸出是Uo。變頻器的調(diào)定值Ui等于或者是按比例到要求的輸出電壓Uo。這個轉(zhuǎn)換器是一個負(fù)電壓反饋閉環(huán)系統(tǒng)。1·2功率開關(guān)電路圖2所示電路的電源開關(guān)半橋接模式，L1和C1構(gòu)成一個輸入濾波器來避免高頻脈沖反流，C2和C3電容器與電阻R1和R2分別構(gòu)成部分電壓回路，T1和T2是半導(dǎo)體開關(guān)，C6是一個分離直流電容器，T1是一個減少電壓的變壓器，L2和C7構(gòu)成一個輸出過濾器，RL是負(fù)載電阻。當(dāng)逆向半波上的PWM信號均在T1和T2的控制限時，相應(yīng)的直流電壓可以從自己的變換器中產(chǎn)生。圖2電路的電源開關(guān)半橋接模式1·3控制電路用于PWM控制電路的SG3525芯片如圖3所示，Vcc是芯片的電源電壓，它是12V，在芯片腳16上5.1V的基極電壓部分作為參數(shù)輸入界面電壓Ui，芯片包含一個鋸齒波發(fā)生器，Rt和Ct是確定的鋸齒波頻率的外部電阻和電容，芯片的腳2是正的輸入端口，輸入電壓Ui是針對端口，Ui=2.5V，芯片的腳1是輸入反饋電壓的負(fù)輸入端，芯片的腳9是芯片內(nèi)部放大器輸出結(jié)果。連接在腳1和腳9之間適當(dāng)?shù)碾娮韬碗娙輰崿F(xiàn)直流—直流變換器的補(bǔ)償。C8是積分電容，采用整體補(bǔ)償系統(tǒng)的補(bǔ)償制度，PWM脈沖從腳11和腳4產(chǎn)生，當(dāng)PWM控制電路正常運行時，腳2上的Ui和腳1上的Ub應(yīng)該平衡，當(dāng)Ui不等于Ub時，PWM技術(shù)寬度可自動調(diào)節(jié)PWM控制電路使Ui等于Ub，通過這種方法我們可以控制變壓器的輸出電壓。圖3用于PWM控制電路的SG3525芯片1·4驅(qū)動電路IGBT驅(qū)動電路通常采用脈沖變壓器或光耦合器通過控制電路隔離電源電路，如果光耦合器需要使用個人電源，就會增加系統(tǒng)的復(fù)雜度，所以隔離電路采用脈沖變壓器如圖4所示，如圖4中晶體管BG1和BG2組成一個互補(bǔ)的功率放大電路，T2是控制電路中的脈沖變壓器隔離電路，R5和C8組成加速電路，二極管D6消除負(fù)脈沖，二極管D7和晶體管BG3在IGBT的控制下組成快速放電電路分布電容。圖41GBT驅(qū)動電路原理2建模和控制2·1建模直流—直流轉(zhuǎn)換器是一個電壓負(fù)反饋系統(tǒng)，以獲得良好的動態(tài)和靜態(tài)特性，我們必須理論上模型和分析，根據(jù)參考【1】，直流—直流轉(zhuǎn)換器是近似二階系統(tǒng)，為了獲得正確的參數(shù)，本文采用對單位階躍函數(shù)輸入系統(tǒng)響應(yīng)的方法。2·1·1對單位階躍函數(shù)輸入的開環(huán)系統(tǒng)響應(yīng)測量測量原理框圖如圖５所示，基本方法是描述如下：①電壓反饋信號被切斷②調(diào)定值上的芯片SG3525采用中等價值Uio是每個脈沖密度達(dá)到大約0.5特，③Uio與Uio，它將會使Uo容易被觀察去選擇矩形波的頻率，采用f1=400赫茲，④Uo的輸出波形如圖6所示，當(dāng)f1=400赫茲時，周期T=2.5毫秒（5格），最大電壓值的時間約為0.1毫秒，Uo為穩(wěn)定電壓幅值時為1ms,峰值超調(diào)為1格，每格在垂直方向代表5V，通過這種方法，系統(tǒng)響應(yīng)的數(shù)據(jù)輸入到一個單位階躍函數(shù)可以得到如下：峰值時間tp=0.1ms峰值超調(diào)σp=1/2=50%;輸出和輸入的增量的比Ko=dUo/dUi=10/1=10.圖5開環(huán)系統(tǒng)測量原理框圖圖6對單位階躍函數(shù)輸入系統(tǒng)響應(yīng)2·1·2開環(huán)傳遞函數(shù)的確定根據(jù)參考【2、3】，我們有阻尼比ξ、被控制對象Gp(s)、固有頻率ωn無阻尼自由振動微分方程：為了確保輸出電壓Uo=2.4V電壓反饋給SG3525腳1的為2.5V，來平衡輸出電壓Ui=2.5V時，我們采用反饋和測量的參數(shù)Kb=Ub/Uo=2.5/24=