無交流電動勢、電流傳感器的三相PWM整流器控制-外文翻譯

1、ACVoltageandCurrentSensorlessControlofThree-PhasePWMRectifiersDong-ChoonLee,Member,IEEE,andDae-SikLim1THREE-PHASEPWMRECTIFIERSASystemModelingFig.1showsthepowercircuitofthethree-phasePWMrectifier.ThevoltageequationsaregivenbyeaR pL00i avaeb0R pL0i bvbec00R pL i cvc ( 1)Fig. 1. Three-phase PWM rectifi

2、er without ac-side sensors.where,andarethesourcevoltage,thelinecurrent,andtherectifierinputvoltage,respectivelyandaretheinputresistanceandtheinputinductance,respectively.Whenthepeaklinevoltage,angularfrequency,andinitialphaseanglearegiven,assu mingabalancedthree-phasesystem,thesourcephasevoltageisex

3、pressedaseacos2ebE cos()3eccos(2)3( 2)Wheret0(3)Atransformationmatrixbasedontheestimatedphaseangle,whichtransformst hree-phasevariablesintoasynchronousdqreferenceframe,is1Ccos23sincos( M2)cos( M2)M33Msin( M32)sin( M32)( 4)Transforming( 1) intothe referenceframeusing(4)eqcR pLM L iqcvqcedcM LRpLidcvd

4、c( 5)wherepisadifferentialoperatorand. MMExpressing( 5) inavectornotationeRiM LJipLiv ( 6)where,eeqciqcvqcJ0 1ivvdc ,10(7)edc ,idc ,Takingatransformationof( 2) byusing( 4)eE cosE sin( 8)WhereM (9)Expressing( 6) and( 8) inadiscretedomain,byapproximatingthederivativeter min( 6) byaforwarddifference 9,

5、respectively,e( k1)Ri(k1)M LJi (k1)Li (k )i (k1)v(k1)T10( )e(k1)E cos( k1)E sin( k1) ( 11)WhereTisthesamplingperiod.2Fig. 2. Overall control block diagram.BSystemControlThePIcontrollersareusedtoregulatethedcoutputvoltageandtheacinputcurrent.Fordecouplingcurrentcontrol,thecross-couplingtermsarecompen

6、satedinafeedforward-typeandthesourcevoltageisalsocompensatedasadisturbance.Fortransientresponseswithoutovershoot,theanti-winduptechniqueisemployed10.TheoverallcontrolblockdiagrameliminatingthesourcevoltageandlinecurrentsensorsisshowninFig.2.Theestimationalgorithmofsourcevoltagesandlinecurrentsisdesc

7、ribedinthefollowingsections.2PREDICTIVECURRENTESTIMATIONThecurrentsofI a ( k)andI c (k)cannotbecalculatedinstantlysincethecalculationtimeoftheDSPisrequired.Toeliminatethedelayeffect,astateobservercanbeused.Inaddition,thestateobserverprovidesthefilteringeffectsfortheestimatedvariable.Expressing( 5) i

8、nastate-spaceform,xAxBu ( 12)yCx ( 13)where,3R1L0ABL10R1L ,0,CL01iqceqcvqcxuidc,edcvdcAndyistheoutput.Transforming( 12) and( 13) intoadiscretedomain,respectively,X (k1)FX (k)GU (k) ( 14)Y (k)HX (k) ( 15)where,1R T1TT0FLGLRT1TT01L,LThen,theobserverequationaddinganerrorcorrectiontermtoisgivenbyX (k 1)

9、F X (k) GU (k )K (Y(k )Y(k ) (16)WhereKistheobservergainmatrixand“”meanstheestimatedquantity,andX (k1)isthestatevariableestimatedaheadonesamplingperiod.Subtracting( 15) from( 16) ,theerrordynamicequationoftheobserverisexpresseda swhereerr (k1) FKCerr ( k) ( 17)err (k )X ( k)X (k ).Here,itisassumedth

10、atthemodelparametersmatchwellwiththerealones.Fig.3showstheblockdiagramoftheclosed-loopstateobserver.Thestatevariableerrordependsonlyontheinitialerrorandisindependentoftheinput.For( 17) toconvergetothezerostate,therootsofthecharacteristicequationof(17) shouldbelocatedwithintheunitcircle.Fig.3. Closed

11、-loop state observer.Fig. 4. Short pulse region.4EXPERIMENTSANDDISCUSSIONSA. SystemHardwareConfigurationFig.5showsthesystemhardwareconfiguration.Thesourcevoltageisathree-phase,110V. Theinputresistanceandinductanceare0.6and3.3mH,respectively.Thedclinkcapacitanceis2350FandtheswitchingfrequencyofthePWM

12、rectifieris3.5kHz.5Fig. 5. System hardware configuration.Fig. 6. Dc link currents and corresponding phase currents ( in sector V ) .TheTMS320C31DSPchipoperatingat33.3MHzisusedasamainprocessorandtwo12-bA/Dconvertersareused.Oneofthemisdedicatedfordetectingthedclinkcurrentandtheotherisusedformeasu6ring

13、thedcoutputvoltageandthesourcevoltagesandcurrents,whereacsidequantitiesarejustmeasuredforperformancecomparison.OneoftwointernaltimersintheDSPisemployedtodecidethePWMcontrolperiodandtheotherisusedtodeterminethedclinkcurrentinterrupt.Consideringtherectifierblankingtimeof3.5s,A/Dconversiontimeof2.6s,an

14、dtheothersignaldelaytime,theminimumpulsewidthissetto10s.A. ExperimentalResults Fig.6showsmeasureddclinkcurrentsandphasecurrents.IncaseofsectorVofthespacevectordiagram,thedclinkcurrentcorrespondstofortheswitchingstateofandforthatof.Fig.7( a) showstherawdclinkcurrentbeforefiltering.Ithasalotofringingc

15、omponentsduetotheresonanceoftheleakageinductanceandthesnubbercapacitor.Whenthedccurrentissampledattheendpointoftheactivevoltagevectorsasshowninthefigure,themeasuringerrorcanbereduced.Fig. 7. Sampling of dc link currents.7Fig. 8. Estimated source voltage and current at starting.Toreducethiserrorfurth

16、er,thelowpassfiltershouldbeemployed,ofwhichresultisshowninFig . 7( b) . Thecut-offfrequencyoftheButterworthssecond-orderfilteris112kHzanditsdelay timeisabout2sec.Sincetheringingfrequencyis258kHzandtheswitchingfrequencyis3.5 kHz,thefilteredsignalwithoutsignificantdelayisacquired.Fig.8showstheestimate

17、dsourcevoltageandcurrentatstarting.Withtheproposedinitialestimationstrategy,thestartingoperationiswellperformed.Fig.9showsthephaseangle,magnitude,andwaveformoftheestimatedsourcevoltage,whichcoincidewellwithmeasuredones.Fig.10showsthesourcevoltageandcurrentwaveformatunitypowerfactor. Figs.Withtheesti

18、matedquantitiesforthefeedbackcontrol,thecontrolperformanceissatisfactory.Thedcvoltagevariationforloadchangeswillberemarkablydecreasedifafeedforwardcontrolfortheloadcurrentisadded,whichispossiblewithoutadditionalcur-rentsensor when the PWM rectifier is combined with the PWMinverter for acmotor drives

19、.8Fig. 9. Estimated source voltage in steady state.( a) phase angle ( b) magnitude ( c) waveform.Fig. 10. Source voltage and current waveforms.(a) estimated ( b) measured.4 CONCLUSIONSThispaperproposedanovelcontrolschemeofthePWMrectifierswithoutemployinganyacinputvoltageandcurrentsensorsandwithusing

20、dcvoltageandcurrentsensorsonly.Reducingthenumberofthesensorsuseddecreasesthesystemcostaswellasimprovesthesystemreliability.Thephaseangleandthemagnitudeofthesourcevoltagehavebeenestimatedbycontr9ollingthedeviationbetweentherectifiercurrentanditsmodelcurrenttobezero.Forlinecurrentreconstruction,switch

21、ingstatesandmeasureddclinkcurrentswereused.Toeliminatetheeffectofthecalculationtimedelayofthemicroprocessor,thepredictivestateobserverwasused.Itwasshownthattheestimationalgorithmisrobusttotheparametervariation.Thewholealgorithmhasbeenimplementedforaproto-type1.5kVAPWMrectifiersystemcontrolledbyTMS32

22、0C31DSP.Theexperimentalresultshaveverifiedthattheproposedacsensoreliminationmethodisfeasible.10無交流電動勢、電流傳感器的三相PWM 整流器控制Dong-ChoonLee,Member,IEEE,andDae-SikLim1 三相 PWM 整流器A 系統(tǒng)模型圖一所示為三相 PWM 整流器的主電路，電壓等式給出如下：eaR pL00i avaeb0R pL0i bvbec00R pL i cvc( 1)圖 1 無交流傳感器三相PWM 整流器其中e i和v分別是源電壓，線電流和整流器的輸入電壓，R和L分別

23、是輸入，電阻和輸入電感。當(dāng)已知線電壓峰值 E，角頻率 和初始相位角 時，假定三相系統(tǒng)是平衡的，則源相位電壓可以表達(dá)為eacos2ebE cos()3eccos(2)32( )其中t0(3)一種基于估計(jì)相位角m 的變換矩陣，將三相變量變換成一個同步的，dq 坐標(biāo)系，這個矩陣是Ccos23sinMMcos(sin(2M32M3)cos()sin(M 2 3 )2)M3( 4)將（ 1）式變?yōu)?dq 坐標(biāo)系使用式（ 4）11eqcR pLM LiqcvqcedcM LR pLidcvdc( 5)其中 p 是一個微分算子且MM將（ 5）式寫成矢量形式eRiM LJipLiv ( 6)其中eqciqcv

24、qc01eivJ0 (7)edc ,idc ,vdc ,1用式（ 4）對（ 2）式進(jìn)行變換E coseE sin( 8)其中M (9)通過前向差分來接近微分的限幅，分別將（6）式和（ 8）式用離散域表示e( k1)Ri(k1)M LJi (k1)Li (k )i (k1)v(k1)( 10)Te(k1)E cos( k1)E sin( k1) ( 11)其中， T 是采樣周期圖 2 總的控制模塊圖B 系統(tǒng)控制12PI 控制器是用來調(diào)節(jié)直流輸出電壓和交流輸入電流的。對于解耦電流控制，交叉耦合項(xiàng)用前饋式補(bǔ)償，同時，源電壓作為擾動的補(bǔ)償。對于沒有過調(diào)的暫態(tài)響應(yīng)，引入 anti-windup 技術(shù)。消

25、除源電壓和線電流傳感器的總的控制模塊圖如圖2 所示。源電壓和線電流的估計(jì)算法在以后的章節(jié)中介紹。2 預(yù)測電流估計(jì)由于 DSP 存在計(jì)算時間，所以 I a (k ) 和 I c ( k) 不能立即計(jì)算。為了消除延遲的影響，可以使用狀態(tài)監(jiān)測器。另外，狀態(tài)監(jiān)測器可以對估計(jì)變量起到濾波作用。將式（ 5）用狀態(tài)空間形式表達(dá)為xAxBu ( 12)yCx ( 13)其中R1L0ABLR1CL ,0L,iqceqcvqcxuidc,edcvdcY 是輸出。分別將式（ 12）和式（ 13）分別變換成離散領(lǐng)域1 00 1X (k1)FX (k)GU (k) ( 14)Y (k)HX (k) ( )15其中1R

26、T1TT0FLRGLT1TT01L,L則加入了誤差調(diào)整的監(jiān)測器等式為X (k1)F X (k)GU (k ) K (Y(k )Y(k ) ( 16)其中， k 是監(jiān)測器增益矩陣，“”是指估計(jì)量， X (k1)是提前一個采樣周期13估計(jì)的狀態(tài)變量。用式（ 15）和減去式（ 16），監(jiān)測器的動態(tài)誤差等式表述為err (k 1) FKCerr ( k) ( 17)其中 err (k )X (k) X (k ) 這里，假設(shè)模型參數(shù)與真實(shí)系統(tǒng)吻合的很好。圖7 所示是閉環(huán)狀態(tài)監(jiān)測器的模塊圖。狀態(tài)變量誤差僅取決于初始誤差，與輸入無關(guān)。為了使式（17）趨于零狀態(tài)，典型等式（ 17）的根應(yīng)該限制在單位圓內(nèi)。圖 3 閉環(huán)狀態(tài)監(jiān)測器圖 4 短脈沖區(qū)域3 實(shí)驗(yàn)與討論A 系統(tǒng)硬件構(gòu)造14圖 5 系統(tǒng)硬件結(jié)構(gòu)圖 6 直流電流和相應(yīng)相電流( 扇區(qū) 5 ) .圖 5 所示是系統(tǒng)的硬件結(jié)構(gòu)圖。源電壓是三相 110V。輸入電阻和電感分別為0.06和 3.3mH。直流側(cè)電容為 2350F，PWM 整流器的開關(guān)切換頻率為 3.5KHZ . 使用 TMS320C31DSP 芯片設(shè)定在 33.3MHZ 作為主處理器，同時用到兩個 12 位的 A /D 轉(zhuǎn)換器：一個用來檢測直流側(cè)電流，另一個用來檢測直流