完整版外文翻译基于PLC异步电动机运行监控系统设计与实施毕业论文.docx

完整版外文翻译基于PLC异步电动机运行监控系统设计与实施毕业论文.docx

《完整版外文翻译基于PLC异步电动机运行监控系统设计与实施毕业论文.docx》由会员分享，可在线阅读，更多相关《完整版外文翻译基于PLC异步电动机运行监控系统设计与实施毕业论文.docx（13页珍藏版）》请在冰点文库上搜索。

完整版外文翻译基于PLC异步电动机运行监控系统设计与实施毕业论文

DesignandImplementationofPLC-BasedMonitoringControlSystemforInductionMotor

ZHUShao-ying，XUYu，HeZheng-wen

XianJiaotongUniversity，Xian710049，P.R.China

Abstract：

Theimplementationofamonitoringandcontrolsystemfortheinductionmotorbasedonprogrammablelogiccontroller（PLC）technologyisdescribed.Also,theimplementationofthewiththeresultsobtainedfromtestsoninductionmotorperformanceisprovided.ThePLCcorrelatestheoperationalparameterstothespeedrequestedbytheuserandmonitorsthesystemduringnormaloperationandundertripconditions.TestsoftheinductionmotorsystemdrivenbyinverterandcontrolledbyPLCproveaspeedregulationascomparedtoaconventionalcontrolsystem.TheefficiencyofPLCcontrolisincreasedatindustrialcontrolofelectricdrives.

Keywords：

Computer-controlledsystems,computerizedmonitoring,electricdrives,inductionmotors,motioncontrol,programmablelogiccontrollers（PLCs）,variable-frequencydrives,voltagecontrol.

I.INTRODUCTION

Sincetechnologyformotioncontrolofelectricdrivesbecameavailable,theuseofprogrammablelogiccontrollers（PLCs）withpowerelectronicsinelectricmachinesapplicationsintroducedinthemanufacturingautomation[1],[2].Thisuseoffersadvantagessuchaslowervoltagedropwhenturnedonandtheabilitytocontrolmotorsandotherequipmentwithavirtuallyunitypowerfactor[3].ManyfactoriesusePLCsinautomationprocessestodiminishproductioncostandtoincreasequalityandreliability[4]–[9].Otherapplicationsincludemachinetoolswithimprovedprecisioncomputerizednumericalcontrol（CNC）duetotheuseofPLCs[10].Toobtainaccurateindustrialelectricdrivesystems,itisnecessarytousePLCsinterfacedwithpowerconverters,personalcomputers,andotherelectricequipment[11]–[13].Nevertheless,thismakestheequipmentmoresophisticated,complex,andexpensive[14],[15].

FewpaperswerepublishedconcerningdcmachinescontrolledbyPLCs.TheyreportboththeimplementationofthefuzzymethodforspeedcontrolofadcmotorgeneratorsetusingaPLCtochangethearmaturevoltage[16],andtheincorporationofanadaptivecontrollerbasedontheself-tuningregulatortechnologyintoanexistingindustrialPLC[17].Also,othertypesofmachineswereinterfacedwithPLCs.Thereby,anindustrialPLCwasusedforcontrollingsteppermotorsinafive-axisrotorposition,directionandspeed,reducingthenumberofcircuitcomponents,loweringthecost,andenhancingreliability[18].Forswitchedreluctancemotorsasapossiblealternativetoadjustablespeedacanddcdrives,asinglechiplogiccontrollerforcontrollingtorqueandspeedusesaPLCtoimplementthedigitallogiccoupledwithapowercontroller[19].OtherreportedapplicationconcernsalinearinductionmotorforpassengerelevatorswithaPLCachievingthecontrolofthedrivesystemandthedataacquisition[20].Tomonitorpowerqualityandidentifythedisturbancesthatdisruptproductionofanelectricplant,twoPLCswereusedtodeterminethesensitivityoftheequipment[21].

II.PLCASSYSTEMCONTROLLER

APLCisamicroprocessor-basedcontrolsystem,designedforautomationprocessesinindustrialenvironments.Itusesaprogrammablememoryfortheinternalstorageofuser-orientatedinstructionsforimplementingspecificfunctionssuchasarithmetic,counting,logic,sequencing,andtiming[23],[24].APLCcanbeprogrammedtosense,activate,andcontrolindustrialequipmentand,therefore,incorporatesanumberofIOpoints,whichallowelectricalsignalstobeinterfaced.InputdevicesandoutputdevicesoftheprocessareconnectedtothePLCandthecontrolprogramisenteredintothePLCmemory（Fig.1）.

Fig.1.ControlactionofaPLC.

III.CONTROLSYSTEMOFINDUCTIONMOTOR

InFig.2,theblockdiagramoftheexperimentalsystemisillustrated.Thefollowingconfigurationscanbeobtainedfromthissetup.

a）Aclosed-loopcontrolsystemforconstantspeedoperation,configuredwithspeedfeedbackandloadcurrentfeedback.Theinductionmotordrivesavariableload,isfedbyaninverter,andthePLCcontrolstheinverterVfoutput.

b）Anopen-loopcontrolsystemforvariablespeedoperation.TheinductionmotordrivesavariableloadandisfedbyaninverterinconstantVfcontrolmode.

c）Thestandardvariablespeedoperation.Theinductionmotordrivesavariableloadandisfedbyaconstantvoltage-constantfrequencystandardthree-phasesupply

Theopen-loopconfigurationb）canbeobtainedfromtheclosed-loopconfigurationa）byremovingthespeedandloadfeedback.Ontheotherc）resultsiftheentirecontrolsystemisbypassed.

IV.HARDWAREDESCRIPTION

Thecontrolsystemisimplementedandtestedforawoundrotorinductionmotor,inTableI.Theinductionmotordrivesadcgenerator,whichsuppliesavariableRload.Thethree-phasepowersupplyisconnectedtoathree-phasemainswitchandthentoathree-phasethermaloverloadrelay,whichprovidesprotectionagainstcur-rentoverloads.Therelayoutputisconnectedtotherectifier,whichrectifiesthethree-phasevoltageandgivesadcinputtotheinsulatedgatebipolartransistor（IGBT）inverter.Itstechnicalspecifications[25]aresummarizedinTableII.TheIGBTinverterconvertsthedcvoltageinputtothree-phasevoltageoutput,whichissuppliedtothestatoroftheinductionmotor.OntheotheraPLCmodularsystem[5],[26]–[28].ThePLCarchitecturereferstoitsinternalareshowninTablesIIIandIV.

Aspeedsensorisusedforthespeedfeedback,acurrentsensorisusedfortheloadcurrentfeedback,andasecondcurrentsensorisconnectedtothestatorcircuits[32].Thus,thetwofeedbackloopsoftheclosed-loopsystemaresetupbyusingtheloadcurrentsensor,thespeedsensor,andtheAIM.

V.RESULTS

Thesystemwastestedduringoperationwithvaryingloadsincludingtestsoninductionmotorspeedcontrolperformanceandtestsfortripsituations.ThePLCmonitorsthemotoroperationandcorrelatestheparametersaccordingtothesoftware.

Atthebeginning,forreferencepurposes,theperformanceofinductionmotorsuppliedfromastandard380V,50-Hznetworkwasmeasured.Then,theexperimentalcontrolsystemwasoperatedbetweennoloadandfullload（1.0Nm）inthetwodifferentmodesdescribedinSectionIII:

a）inductionmotorfedbytheinverterandwithPLCcontrol;

b）inductionmotorfedbytheinverter.

TherangeofloadtorqueandofspeedcorrespondstothedesignofthePLCtheprevioussections.

Thespeedversustorquecharacteristicswerestudiedintherange500–1500rminandisillustratedinFig.7.Theresultsshowthatconfigurationb）operateswithvaryingspeed-varyingloadtorquecharacteristicsfordifferentspeedsetpoints.Configurationa）operateswithconstant-speed-varyingloadtorquecharacteristicsinthespeedrange0–1400rminand0–100%loads.However,intherangeofspeeds1400rminandloads70%,thesystemoperateswithvarying-speed-varying-loadandtheconstantspeedwasnotpossibletobekept.Thus,for1400rminbothcon-figurationsa）andb）93%ofthesynchronous.

Fig.6.Flowchartofcutoffrestartmotorsoftware.

Theefficiencyfordifferentvaluesofwasalsostudied.InFig.8,theefficiencyisshownnormalized,usingasbasevalueor1p.u.theefficiencyoftheinductionmotorsuppliedfromthestandardnetwork.AsdepictedinFig.8,theresultsshowthatconfigurationa）inallcasesconfigurationb）.Also,atoperationwithloads70%,thenormalizedefficiencyis>1,meaningthattheobtainedefficiencywithPLCcontrolistheefficiencyofinductionmotoroperatedfromthestandard380-V,50-HznetworkwithoutthecontrolofPLCandwithouttheinverter.Accordingtothisfigure,theefficiencyofPLC-controlledsystemisincreasedupto10–12%comparedtothestandardmotoroperation.

Fromatheoreticalpointofview,ifweneglectmagnetizingcurrent,anapproximatevaluefortheefficiencyis

wheresistheslipandarethestatorandrotorwindingresistances,respectively.AscanbeseenfromFig.7,thePLC-controlledsystema）workswithverylowslipvalues,almostzero.Inallspeedandloadtorqueconditions,theconfigurationa）configurationb）,thusthebejustifiedandespeciallyatincreaseinmagnetizingcurrentresultinginincreasedlosses.

Thissystempresentsasimilardynamicresponseastheclosed-loopsystemwithVfspeedcontrol.Itstransientperformanceislimitedduetooscillationsontorque[32]andthisbehaviorrestrictstheapplicationofthissystemtoprocessesthatonlyrequireslowspeedvariation.

VII.CONCLUSION

SuccessfulexperimentalresultswereobtainedfromthepreviouslydescribedschemeindicatingthatthePLCcanbeusedinautomatedsystemswithaninductionmotor.ThemonitoringcontrolsystemoftheinductionmotordrivenbyinverterandcontrolledbyPLCprovesitsspeedregulationatconstant-speed-variable-loadoperation.

TheeffectivenessofthePLC-basedcontrolsoftwareissatisfactoryupto96%ofthesynchronousspeed.TheobtainedefficiencybyusingPLCcontrolisincreasedascomparedtotheopen-loopconfigurationoftheinductionmotorfedbyaninverter.Specifically,atoftheinductionmotorsuppliedfromastandardnetwork.

Despitethesimplicityofthespeedcontrolmethodused,thissystempresents:

•constantspeedforchangesinloadtorque;

•fulltorqueavailableoverawiderspeedrange;

•verygoodaccuracyinclosed-loopspeedcontrolscheme;

•.

Thus,thePLCprovedtobeaversatileandefficientcontroltoolinindustrialelectricdrivesapplications.

References

[1]BashoreD,OliaroG,RoneyP,etal.FusionEngineeringandDesign,1999,43:

239

[2]zuruYon