外文翻译变频器使用浅谈精品.docx

外文翻译变频器使用浅谈精品.docx

《外文翻译变频器使用浅谈精品.docx》由会员分享，可在线阅读，更多相关《外文翻译变频器使用浅谈精品.docx（9页珍藏版）》请在冰豆网上搜索。

外文翻译变频器使用浅谈精品

Thefrequencyconverterisusedanddiscussedlightly

Theasynchronousmotorissuchmainpowerequipmentofmanufacturingenterpriseaselectricity,chemicalindustry,etc..Asthehighenergyconsumptionequipment,itsoutputpowercan'tbeuptothechangeprorataofload,majoritycanonlyturnonthroughguardorvalvedegreeregulate,buttheenergythatthemotorconsumesdoesnotchangemuch,thuscauseverygreatenergytoloss.Inrecentyears,onethatiswiththematurityoftheproductiontechnologyofthefrequencyconverterandrangeofapplicationoffrequencyconverterisextensivedaybyday,usethefrequencyconvertertocarryontechnologytotransformtothemotorpowerintotheenergy-conserving,high-efficiencyimportantmeansofeveryenterprise.

1.Frequencyconversionadjuststhespeedprinciple

n＝60f（1－s）/p

（1）Inthetype

n---Rotationalspeedoftheasynchronousmotor;

f---Frequencyoftheasynchronousmotor;

s---Themotoristransferedtothedifferencerate;

p---Logarithmverymuchofthemotor。

Canknowbytype

（1）rotationalspeednindirectproportiontofrequencyf,onlyneedchangefrequencyfandchangetherotationalspeedofthemotor,motivepowerfrequencyrealizethatspeedregulate.

Thefrequencyconverterismainlyadoptedandhandedin-frank-handoverthesidewhenfrequencyfchangesintherangeof0-50Hz,therotationalspeedofthemotorregulatestherangeverywidely.Frequencyconversiontransferspeedpasspersonwhochangeselectricity,exchangefrequentlyworkerpowerchangethroughtherectifierintoadirectcurrentsourcefirstjust,thenchangethedirectcurrentsourceintothefrequency,exchangepowercontrollableinvoltageinordertosupplythemotor.Thefrequencyconverteronethereisgenerallyfromrectificationcircuit,inthemiddleofdirectcurrentlink,goagainstnotbecomingandcontrollingpartingof4piecesnottomakeup.Rectificationpartthree-phasebridgecontrolledrectifier,isitchangesomeintoIGBTthree-phasebridgetypegoagainstthengdevicetogoagainst,andoutputforPWMwaveform,middledirectcurrentforstrainwave,directcurrentenergystorageandbufferinactivepowerlink.

Thewaveinharmonyissuppressed

Outstandingproblemthatfrequencyconverterusewhetherinharmonywaveinterfere,asfrequencyconverterwhenworking,outputinharmonywaveelectriccurrentofelectriccurrentwillleadtothefactinterferingtothepower.Thougheveryfrequencyconverterproducertakemeasuresandreachtofrequencyconverterinharmonyadministrationofwavenationalstandardrequirebasically,questionneedingtopaycloseattentiontomostinbutthewaveinharmonyremainstheselectingtypeofthefrequencyconverteranduses.

Containotherwavesinharmonybesidesbasewaveinthevoltageofoutputofthefrequencyconverter.Lowtimesofinharmonywaveusuallyexertagreatinfluenceonelectricalmachineryload,causethetorquetopulse,andhigherwaveinharmonymakesthefrequencyconverterexportleakingtheelectriccurrenttoincreaseofthecableagain,makeelectricalmachineryexertoneselfinsufficient,soleveltimesofinharmonywavethatfrequencyconverteroutputmustsuppress.

Becausetherectificationpartofthefrequencyconverteradoptsthecontrolledbridgetyperectificationcircuitofdiode,themiddlestrainwavepartadoptlargeelectriccapacityaswavefilter,sointroductionofrectifierelectriccurrenttochargeelectriccurrentcondenserinfact,itisasteeperpulsewave,itswaveinharmonyisrelativelylargeinweight.Inordertodispelthewaveinharmony,adoptthefollowingcountermeasuremainly:

a.Increasefrequencyconvertersupplypowerpowerimpedancegenerally,interiorimpedance,powerofequipmentcanisitbufferfrequencyconverterdirectcurrentstrainfunctionofinactivepower,waveofelectriccapacitytoplay.Impedanceisshortcircuitimpedanceofthevoltagetransformerinthiskind.Lookonpowercapacityrelativecapacitylittlefrequencyconverteras,interiorimpedancevaluerelativeandheavy,thelessthecontentofwaveinharmonyis;Therelativefrequencyconverterofcapacityofthepoweristhelargerincapacity,impedancevalueisrelativelow,thelargerthecontentofwaveinharmonyis.Choosefrequencyconverteratsupplyingpowerpowertransformering,hadbetterisitshortoutimpedanceheavyvoltagetransformertochoose.

b.Installreactorinstallreactortoincreasefromoutsidefrequencyconvertersupplypowerinteriorimpedanceofpoweractually.Installsthereactororinstallsatthesametimeontheexchangesideofthefrequencyconverterorthedirectcurrentsideofthefrequencyconverter,cansuppresstheelectriccurrentofwaveinharmony.

c.Therectificationpartofthefrequencyconverteris6pulsewaverectifiersthatthevoltagetransformerusuallyoperatesheterogeneously,sothewaveinharmonyproducedisrelativelybig.Useheterogeneousoperationofvoltagetransformer,suchasmakephaseplacecornerbadYof30°eachotherY－△、△－△2voltagetransformersmadeupareformedandequivalentto12pulsewaverectifiers,canreducetheelectriccurrentofwaveinharmony,playagoingtothewaveinharmonytosuppressrole.

d.RegulateyearofthefrequencyconverterBobImproveBobinyearofthefrequencyconverter,cansuppresswaveinharmonyonceeffectivelylow.

e.UsethewavefilterWavefiltercanmeasurefrequencyconverterinharmonywaveamplitudeandphaseplaceofelectriccurrent,producetheelectriccurrentcontrarytoelectriccurrentphaseplacethesameinamplitudeofwaveinharmony,thusabsorbeffectively.

3.Matchofload

3.1Squaretorqueload

Airblower,,pumploadwhetherindustryuseequipmentmostlive,frequencyconverteratmostapplicationattheload.Itplantssquaretorqueload.Generallyspeaking,haveU/f=Constcontrolfrequencyconverterofmodecanmeetthedemandofloadbasically,belowfoundationthemaincharacteristicquestionthatneednoticewhenintroducingpersonningwhoselectoffrequencyconverter.

3.1.1Haveavoidedloading

Airblowerdifficultoverloadaswaterpump,guaranteeitgreaterthanormeanthecapacityofthemotorslightlyatthecapacitytochoosefrequencyconverter;Overloadcapacityoffrequencyconverterthatchooseatthesametimerequiretobelowereven,upto120%generally,1min.Butshouldnoticewhenthefunctionparameterofthefrequencyconverterischosenandpresetted,becausetheloadonehindersthetorqueindirectproportiontothesquareofrotationalspeed,whentheoperatingfrequencyishigherthanthespecifiedfrequencyofthemotor,tohindertorquecanexceedthespecifiedtorqueload,overfreightmotor.Soisitcontrolsupremeoperatingfrequencycanexceedthespecifiedfrequencyoftheelectricalmachinerystrictlytowant.

3.1.2Matchthatthefrequencyconverteracceleratestimeandmoderatestimewhileopening/stopping

Becauseairblowerandloadofpumprotateinertiatobeheavy,itstartandwhenstoppingwithtoacceleratetimeandmoderatetimeitmatchestobeoneimportantproblemveryfrequencyconverter.Personwhoselectwhenusing,shouldcalculatetoacceleratetimeandmoderateaccordingtoloadparametertimechooseshorttimemostfrequencyconverterinfrequencyconverter,inordertotakeplacesituationthatvoltagetripwhenthefrequencyconverterhasnotflowedtotripwhilestartingandthefrequencyconverterismoderated.Butintheproductiontechnologysometimes,demandtobeverystricttothestart-uptimeofairblowerandpump,ifabove-mentionedtimethatcalculatecanatmeetingdemanding,shouldredesigntheselectingtypetothefrequencyconverter.

3.1.3Avoidtheresonance

Becausefrequencyconverterthroughchangepowerfrequencyofmotorisitchangeelectricalmachineryrotationalspeedrealizeenergy-conservingresulttocome,possibleunderacertainelectricalmachineryrotationalspeedandloadsomeresonance,axleofdepartment,,resonancefrequencycoincident,causeloadaxlevibrationthatdepartmentcantolerate,causeequipmentstoppageintransitorequipmentdamagesometimes,sowhenthefunctionparameterofthefrequencyconverterischosenandpresetted,shouldfollowtheresonancefrequencyoftheaxledepartmentofload,throughisitjumpsomefrequencyandwidthtoestablish,preventsystemfromtheresonancephenomenontakeplace.

3.1.4Suppressandpressitwithwaterhammereffect

Pumploadeasytoisitsuppresskeepandwaterhammereffecttohappeninthecourseofoperatingactually,soatthetimeoftheselectingtypeofthefrequencyconverter,shouldestablishalonetothisquestionwhenthefunctionisestablished.

a.SuppressandpressWhilerunningatalowspeed,becauseitexportthedoortomakethepressurerisetocloseinpumpload,thuscausethevapourofthepumptolose.Whenthefunctionofthefrequencyconverterisestablished,throughlimitminimumfrequencyoffrequencyconverterisitlimitminimumrotationalspeedofcriticalpoint,pumpofflowtocome,canavoidtheemergenceofthiskindofphenomenon.

b.WaterhammereffectPumploadflowsbackwardsbecauseofliquidgravityinthepumppipelinewhilesuddenlycuttingout.Isitstopvalvetobetightagainststopvalve,leadingtothefactelectricalmachineryoverturn,makefrequencyconverterbreakdownorburnoutbecausetheelectricalmachinerygenerateselectricitytogoagainst.Inthesystematicdesignofthefrequencyconverter,shouldmakethefrequencyconverterstopaccordingtothecontoursofmoderating,disconnectthemaincircuitaftertheelectricalmachinerytotallystops,orestablishthe"cuttingoutandmoderatingstopping"