无交流电动势、电流传感器的三相PWM整流器控制-外文翻译

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无交流电动势、电流传感器的三相PWM 整流器控制Dong-ChoonLee,Member,IEEE,andDae-SikLim1 三相 PWM 整流器A 系统模型图一所示为三相 PWM 整流器的主电路，电压等式给出如下：eaR pL00i avaeb0R pL0i bvbec00R pL i cvc( 1)图 1 无交流传感器三相PWM 整流器其中e i和v分别是源电压，线电流和整流器的输入电压，R和L分别

23、是输入，电阻和输入电感。当已知线电压峰值 E，角频率 和初始相位角 时，假定三相系统是平衡的，则源相位电压可以表达为eacos2ebE cos()3eccos(2)32( )其中t0(3)一种基于估计相位角m 的变换矩阵，将三相变量变换成一个同步的，dq 坐标系，这个矩阵是Ccos23sinMMcos(sin(2M32M3)cos()sin(M 2 3 )2)M3( 4)将（ 1）式变为 dq 坐标系使用式（ 4）11eqcR pLM LiqcvqcedcM LR pLidcvdc( 5)其中 p 是一个微分算子且MM将（ 5）式写成矢量形式eRiM LJipLiv ( 6)其中eqciqcv

24、qc01eivJ0 (7)edc ,idc ,vdc ,1用式（ 4）对（ 2）式进行变换E coseE sin( 8)其中M (9)通过前向差分来接近微分的限幅，分别将（6）式和（ 8）式用离散域表示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 是采样周期图 2 总的控制模块图B 系统控制12PI 控制器是用来调节直流输出电压和交流输入电流的。对于解耦电流控制，交叉耦合项用前馈式补偿，同时，源电压作为扰动的补偿。对于没有过调的暂态响应，引入 anti-windup 技术。消

25、除源电压和线电流传感器的总的控制模块图如图2 所示。源电压和线电流的估计算法在以后的章节中介绍。2 预测电流估计由于 DSP 存在计算时间，所以 I a (k ) 和 I c ( k) 不能立即计算。为了消除延迟的影响，可以使用状态监测器。另外，状态监测器可以对估计变量起到滤波作用。将式（ 5）用状态空间形式表达为xAxBu ( 12)yCx ( 13)其中R1L0ABLR1CL ,0L,iqceqcvqcxuidc,edcvdcY 是输出。分别将式（ 12）和式（ 13）分别变换成离散领域1 00 1X (k1)FX (k)GU (k) ( 14)Y (k)HX (k) ( )15其中1R

26、T1TT0FLRGLT1TT01L,L则加入了误差调整的监测器等式为X (k1)F X (k)GU (k ) K (Y(k )Y(k ) ( 16)其中， k 是监测器增益矩阵，“”是指估计量， X (k1)是提前一个采样周期13估计的状态变量。用式（ 15）和减去式（ 16），监测器的动态误差等式表述为err (k 1) FKCerr ( k) ( 17)其中 err (k )X (k) X (k ) 这里，假设模型参数与真实系统吻合的很好。图7 所示是闭环状态监测器的模块图。状态变量误差仅取决于初始误差，与输入无关。为了使式（17）趋于零状态，典型等式（ 17）的根应该限制在单位圆内。图 3 闭环状态监测器图 4 短脉冲区域3 实验与讨论A 系统硬件构造14图 5 系统硬件结构图 6 直流电流和相应相电流( 扇区 5 ) .图 5 所示是系统的硬件结构图。源电压是三相 110V。输入电阻和电感分别为0.06和 3.3mH。直流侧电容为 2350F，PWM 整流器的开关切换频率为 3.5KHZ . 使用 TMS320C31DSP 芯片设定在 33.3MHZ 作为主处理器，同时用到两个 12 位的 A /D 转换器：一个用来检测直流侧电流，另一个用来检测直流