变频调速相关英文文献---外文翻译

DesignofVariableFrequencySpeedControlSystemBaseOnPLCAndFuzzyAlgorithmMing-junYAN1aShao-fengYAN1LiaoningRailwayVocationalandTechnologicalCollege,Jinzhou121000,China2FacultyofMechanicalEngineering&Automation,LiaoningUniversityofTechnology,Jinzhou,121001,China;E-mail:[e-mail];Keyword:PLC;fuzzyalgorithm;variablefrequencyspeedcontrol;closedloopcontrolAbstract:Aimingatacmotorclosed-loopcontroldifficult,afrequencyconversionsystemwasdesignedbaseonPLCandfuzzyalgorithm.ThispaperdealswithaPLCandfrequencyconvertercontroleACinductionmotormethod,aswellasconstructedtwo-dimensionalfuzzycontrollerbyPLC,realizethedynamiccontrolofnonlinearsystems,avoidingthecomplexityofmodeling,improvethesystemstabilityandanti-jammingcapability.On-sitetestingshowsthatthissystemhasahighintelligenceandbetterrobustness,canfrequencycontrolofmotorspeedaccurately.IntroductionAcinductionmotorischeap,easymaintenance,andsuitableforthebadenvironmentinuse.Butitisdifficulttodefinemathematicalmodeloftheacmotor,andthecalculationiscomplicated.Combiningwiththevariablefrequencyspeedclosed-loopcontrol,thefuzzycontrolsystembasedonPLCisputforwardinthepaper.Theadvantageisthatjustaccordingtothecontrolexperienceandbyusingfuzzyinferenceansatisfactorycontroleffecttononlinearobjectcanbegot.thesolutionisnotsuresystemoftheeffectiveway.itisaneffectivewaytosolveuncertainsystem.SystemconfigurationThedesignusesPLCandinvertertoadjustacinductionmotorspeed.ThesubstractionofthesettingspeedandtheactualspeedgotfromPLCcontrolmodulefeedbackmakesvelocityerror,thencontrolledvariablecanbegotthroughcalculatingbyPLC.Toachievethepurposeofcontrollingthemotorspeed,thecontrolledvariableshouldbepassedtothefrequenceconverter,whichdrivesacmotor,throughRS-485connector.Thesystemstabilityandanti-jammingabilityareimproved,asusingRS-485signalsdonotneedtobeconvertedbyD/Aconverter.Acmotorusesencodertomeasurespeed,whichovercomesthedeadzoneandnonlinearzonephenomenonthatusuallyexistedbefore,andmeanwhilereducesthevolumeanderror.Systemcompositionasshowninfigure1.Fig.1SystemCompositionThedesignoffuzzycontrollerThestructuredesignofthefuzzycontrollerWith2-dfuzzycontrollerandtheerroranderrorrateofthecontrolledvariablesasinput,thesystemputoutacontrolvariable.Becauseinthecontrolsystemfeedbacksoftheerrorandtheerrorratearedealtatthesametime,thesystemstabilityisensuredandoscillationphenomena[1,2]areprevent.Thefuzzycontrolstructurediagramisshowninfigure2.AdvancedMaterialsResearchVols562-564(2012)pp1931-1934Online:2012-08-30©(2012)TransTechPublications,Switzerlanddoi:10.4028/(ID:121.22.24.8,NortheasternUniversity,Shenyang,China-24/05/15,11:34:35)Fig.2Fuzzycontrolstructureprinciplediagrame(t)andec(t)isseparatelymeaningaccurateoffsetvalueanddeviationrate.Eistheobfuscationofe(t)andECistheobfuscationofec(t).Uisobfuscationoutputafterreasoning.u(t)isaccuratedefuzzificationoutput.obfuscationalgorithmandtherulesErrorfuzzysetandErrorratefuzzysetareselectingsevenelements[5],thatis{NB,NM,NS,0,PS,PM,PB}.Soasthefuzzyoutput.Accordingtothemanualcontroldataandalotofexploratoryrepeatedmanualadjustments,thebasicdomainofthespeeddeviation(e)canbedeterminedas[-8m/s，+8m/s],andthebasicdomainofthedeviation(ec)canbedeterminedas[-5m/s2,+5m/s2].Inordertorealizebycomputereasily,differencescheme[6,7]isadoptedindissociation.()()VkVke−=（2-1）()tkekekec)1()(−−=（2-2）ForVisexpectedspeed.InfuzzycalculationthevalueofeandecmustbetransformedintotheMoHuLundomainofthefuzzycontrollerbyitsquantificationfactors.Quantificationfactorscanbegotasfollowformula:+−−−=2)(**βααβeeabki（2-3）For[]βα,isactualdomain;[]ba,isbasicdomain.ComprehensivelyconsideringtheconcisenessofthePLCprogrammingalgorithmandthegeneralityinpracticaluse,thetrianglemembershipfunctionsareadopted.()[]()()≤−−≤−−∉=aubauabuaauacauA,b1,b1,,0µ（2-4）Fuzzycontrolrulesareestablishedbasedonexperienceinduction,namelybasedonoperationexperienceandnecessaryreasoning,sorting,refining,thefuzzycontrolrulesareestablished.Correspondingto2-dfuzzycontroller,aseriesoffuzzycontrolstatementscanbegot.ItsformisifE=XandEC=YthenU=Z.Suchas:ifE=PBandEC=NSthenU=PB;ifE=NSandEC=PSthenU=NS;……………………………………1932MaterialsEngineeringandAutomaticControlDefuzzificationandtheestablishmentoffuzzycontrollerlook-uptableDefuzzificationisrealizedbyusingweightedaveragemethod,whichiswidelyusedamongfuzzyalgorithmicapproaches.Theweightedaveragemethodformulaisasfollows:()()jUJjUµµ∑•∑=*u（2-5）ForlUrepresentseachfuzzysubsetsoutput;()jUwjµandjwseparatelyrepresentsMembershipFunctionsanditsvalues;*urepresentsaccurateoutputvalues.Relativetothediscretizationformofthefuzzyoutputvector,itsfuzzyoutputsubsetisexpressedasfollows:654561312321+++++−+−+−=µµµµµ

U（2-6）Relativetothediscretizationformofthefuzzyoutputvector,thecomputingmethodofdefuzzificationcanbeexpressedasfollows:()()()()()[]∑=+×++×++−×+−×+−×=1311312321*65456iluµµµµµ