中英翻译--开关电源.doc

SwitchingPowerSupplySwitchingpowersupplyisavoltageconversioncircuit,themainworkisthestep-upandstep-down,arewidelyusedinmodernelectronicproducts.Alwaysworkbecausetheswitchingtransistorintheonandoffstate,socalledswitchingpowersupply.Switchingpowersupplyinrealtermsisanoscillatorcircuit,theconversionofelectricalenergynotonlyusedinpowercircuit,thecircuitinotherapplicationsarealsocommon,suchasLCDbacklightcircuits,suchasfluorescentlamps.Switchthesourcecomparedwiththetransformerhighefficiency,goodstability,smallsizeandotheradvantages,disadvantagesistherelativelysmallpower,andhigh-frequencyinterferenceonthecircuit,circuitcomplexity,suchaseasymaintenance.Talkingaboutswitchingpowersupplybeforeyoufamiliarwiththefeedbackoscillatorcircuittransformer,canproducearegularpulsecurrentorvoltageofthecircuitiscalledoscillationcircuit,transformerfeedbackoscillatorcircuitisabletomeettheseconditionsthecircuit；itinthebasicamplifiercircuitwithafeedbackloopcomposedofC2,L1electiontoformaparallelresonantfrequencycircuit,theinstantaneouspowerinthecircuitturn-VT,thistimeintheC2,L1,composedofparallelresonantcircuitshaveaveryrichharmonic,whentheplusparallelresonancefrequencyandthenaturalfrequencyofthesamecircuit,thecircuittoenterastateofoscillation,andVTthroughL3feedbacktofurtherenlargethebase,andultimatelytheformationofaregularpulsecurrentorvoltageoutputtotheloadRL.Switchingpowersupplyisaroundthetransformerandthefeedbackoscillatorcircuitdesign,butthebasisoftheoriginalincreaseinthenumberofprotectionandcontrolcircuits,analysisofouroscillationcircuitcanbeusedtoanalyzethemethodofswitchingpowersupply.SwitchingPowerSupplyvibrationbywayofsub-swingcanbedividedintoself-excitedanditexcitedthetwo,sincethereisnoneedforplus-excitedself-oscillationsignalsource,sincetheexcitationcanseeitasafeedbackoscillatorcircuittransformer,anditisexcitedistotallydependentontheoutsidetomaintaintheoscillation,inthepracticalapplicationofself-excitationofacomprehensiverangeofapplications.Accordingtothestructureofincentivessignalclassification；canbedividedintopulse-width-modulatedpulseamplitudemodulationandtwopulse-width-modulatedsignaltocontrolthewidth,thatis,frequency,pulseamplitudemodulationcontrolsignalofthemagnitudeoftheroleofthetwothesamesothatoscillationfrequencyismaintainedatwithinacertainrange,totheeffectofvoltagestability.Windingtransformercanbedividedintothreetypesingeneral,agroupinvolvedintheprimarywindingoftheoscillation,agroupistomaintaintheoscillationofthefeedbackwinding,thereisagroupoftheloadwindings.Householdappliancesusedinswitchingpowersupply,aftertheACto220Vbridgerectifier,convertedintoabout300VDC,filterintothetransformerisaddedaftertheswitchtohigh-frequencyoscillationsofthecollector,feedbackwindingbacktothebasetomaintaintheoscillationcircuit,loadsensorwindingsoftheelectricalsignal,byrectification,filtering,theDCvoltageregulatorhasbeentoprovidepowertotheload.Windingintheprovisionofelectricpowerload,butalsotakeupthecapacityofvoltagestability,thetheoryisthenacircuitvoltageoutputvoltagesamplingdevicestomonitortheoutputvoltagechanges,timelyfeedbacktoadjusttheoscillationfrequencyoscillatorcircuittoachievethevoltagestabilityThepurposeofthecircuitinordertoavoidinterference,thefeedbackvoltagetotheoscillatorcircuitwillbeisolatedoptocoupler.Mostswitcheshaveastandbypowercircuit,switchingpowersupplyinstandbymodestilloscillating,butthefrequencyofnormalworkinghoursthanlower.Someswitchingpowersupplyarecomplex,numerouscomponents,manyprotectionandcontrolcircuit,intheabsenceoftechnicalsupport,maintenanceisaheadachewiththematter.Ifacethiskindofsituationis,firstofall,Iwillfindtheswitchanditsparticipationintheexternaloscillationcircuit,itseparatedfromthecircuittoseeifitmettheconditionsforoscillation,suchasdetectionbiasandwhetheritisnormal,whetherpositivefeedbackfailure,aswellasitsownswitches,switchingpowersupplyhasverylargeprotection,afterexclusionoftheprosecutionandloadcontrolandprotectioncircuit.thecontrolcircuitwhileoutputfromthesample,withthesetstandards,thencontrolledinverter,changeitsfrequencyorpulsewidthoutputachievestability,ontheotherhand,accordingtotestdataprovidedbythecircuitbycircuitprotectionidentification,Controlcircuitfortheunitforvariousprotectionmeasures.SMPSdevelopmentsandtrendsintheUnitedStatesin1955Roje(GH.Roger)inventionoftheself-excitedoscillationpushredeemtransistorsingletransformerDCconverters,high-frequencyconversionisthebeginningofcontrolcircuit,1957UnitedStatesinvestigationtournament(JenSen)sincetheinventionofthepush-pulldoubleFlybacktransformers,1964Americanscientistsproposestoabolishthefrequencytransformerseriesswitchingpowersupplyscenario,Thispowertotherightsizeandweightofthedeclinewasafundamentalway.Tothe1969high-powersilicontransistorbecausethepressureincreasediodereverserecoverytimeshortened,andothercomponentsimprove,andfinallyturnedintoa25kHzswitchingpowersupply.Currently,switchingpowersupplytosmall,Lightvolumeandthecharacteristicsofhighefficiencyhasbeenwidelyusedinelectroniccomputer-drivenvarietyofterminalequipment,Communicationsequipmentalmostallelectronicequipment,theelectronicinformationindustryindispensabletotherapiddevelopmentofapowermode.Currentlythemarketforsaleintheswitchingpowersupplyusingbipolartransistorsmadeof100kHz.usemadeof500kHzMOSpower,thoughpractical,butitsfrequencytobefurtherenhanced.Toimprovetheswitchingfrequency,itisnecessarytoreducetheswitchingloss,andtoreducetheswitchingloss,youneedtohavehigh-speedswitchingdevices.However,theswitchingspeed,willbeaffectedbythecircuitinductanceandcapacitancediodeorstoredchargearisingfromtheimpactofthesurgeornoise.Thiswillnotonlyaffectthesurroundingelectronicequipment,butalsogreatlyreducethereliabilityofthepowersupplyitself.Amongthem,withtheswitchtopreventKai-closedbythevoltagesurge,itisR-CorL-CCompositebumpers,andthestoragechargebythediodecurrentsurgecausedbytheusemadeofamorphouscoressuchasmagneticbumper.However,thehighfrequencyof1MHzandabove,usingresonantcircuit,Switchtoenablethevoltageorcurrentthroughtheswitchwasasine,whichcouldreducetheswitchingloss,Thiscanalsocontrolthesurgeoccurred.Switchessuchasresonantmodeswitching.CurrentlysuchSMPSofveryactive,becausethismeansnosignificantincreaseswitchingspeedcantheoreticallyputswitchinglossfalltozero.andthenoiseissmall,isexpectedtobecomehigh-frequencyswitchingpowersupplyofoneofthemainways.Atpresent,manycountriesintheworldareworkingonseveraltrillionHzconverterpracticalresearch.开关电源开关电源是一种电压转换电路，主要的工作内容是升压和降压，广泛应用于现代电子产品。因为开关三极管总是工作在“开”和“关”的状态，所以叫开关电源。开关电源实质就是一个振荡电路，这种转换电能的方式，不仅应用在电源电路，在其它的电路应用也很普遍，如液晶显示器的背光电路、日光灯等。开关源与变压器相比具有效率高、稳性好、体积小等优点，缺点是功率相对较小，而且会对电