Classificationrelationship
ClassificationofDCpowersupplies:
DCpowersuppliesaredividedintolinearDCpowersuppliesandhigh-frequencyswitchingpowersupplies.
Workingprinciple
TheworkingprocessofthemaincircuitofthelinearpowersupplyisthattheinputpowerisfirstsubjectedtoapreliminaryACvoltagestabilizationbyapre-regulatedcircuit,andthentransformedintoaDCpowersupplythroughtheisolationandrectificationofthemainworkingtransformer.Thenthroughtheintelligentcontrolofthecontrolcircuitandthesingle-chipmicro-processingcontroller,thelinearadjustmentelementisfinelyadjustedtooutputahigh-precisionDCvoltagesource.
1,powertransformerandrectifier:TheACpoweristransformedintotherequiredDCpower;
2.Pre-regulationcircuit:TheinputACorDCvoltageispre-regulatedandpre-regulatedbyrelaycomponentsorthyristorcomponents,therebyreducinglinearadjustmentcomponentsPowerconsumption,improveworkefficiency.Andensuretheoutputvoltagesourcehighprecisionandhighstability;
3,linearadjustmentelement:finelyadjustthefilteredDCvoltagetomaketheinputvoltagereachtherequiredvalueAndaccuracyrequirements;
4,filtercircuit:topreventandabsorbthepulsatingwave,interference,andnoiseoftheDCpowersupplytothegreatestextent,soastoensurethattheoutputvoltageoftheDCpowersupplyhaslowripple,lownoiseandlowInterference;
5.Single-chipmicrocomputercontrolsystem:Thesingle-chipmicro-processingcontrollercompares,judges,calculates,analyzesandprocessesvariousdetectedsignals,andthenissuescorrespondingcontrolinstructionstostabilizetheDCTheoverallvoltagestabilizationsystemofthepowersupplyworksnormally,reliablyandcoordinately;
6.Auxiliarypowersupplyandreferencevoltagesource:providehigh-precisionreferencevoltagesourceandpowersupplyrequiredfortheoperationofelectroniccircuitsfortheDCvoltagestabilizationsystem;
7.Voltagesamplingandvoltageadjustment:detecttheoutputvoltagevalueoftheDCstabilizedpowersupplyandsetandadjusttheoutputvoltagevalueoftheDCstabilizedpowersupply;
8,thecomparisonamplifiercircuit:Theoutputvoltagevalueoftheregulatedpowersupplyiscomparedwiththevoltageofthereferencesourcetoobtaintheerrorvoltagesignal,andthenthefeedbackisamplifiedandthelinearadjustmentelementiscontrolledtoensuretheoutputvoltageisstable;
9.Currentdetectioncircuit:obtainsDCstabilityTheoutputcurrentvalueofthevoltagepowersupplyisusedforcurrentlimitingorprotectioncontrolinformation;
10.Drivecircuit:Apoweramplifiercircuitfordrivingexecutablecomponents;
11.Display:DisplayofoutputvoltagevalueandoutputcurrentvalueofDCstabilizedpowersupply.
Comparisonbetweenlinearpowersupplyandswitchingpowersupply
Thevoltagefeedbackcircuitoflinearpowersupplyworksinlinear(amplified)state,switchingpowersupplymeansthatthetubeusedforvoltageadjustmentworksinsaturationandcut-offZone,thatis,thestateoftheswitch.
Linearpowersuppliesgenerallysampletheoutputvoltageandsendittoacomparisonvoltageamplifierwithareferencevoltage.TheoutputofthisvoltageamplifierisusedastheinputofthevoltageregulatortubetocontrolthejunctionvoltageoftheregulatortubetochangewiththeinputAndchange,therebyadjustingitsoutputvoltage,buttheswitchingpowersupplychangestheoutputvoltagebychangingtheonandofftimeoftheregulatortube,thatis,changingthedutycycle!
Fromthepointofviewofitsmaincharacteristics:thelinearpowersupplytechnologyisverymature,theproductioncostislow,itcanreachahighdegreeofstability,therippleissmall,itsowninterferenceandnoisearerelativelysmall,butbecauseitworksinPowerfrequency(50Hz),thevolumeofthetransformerisrelativelylarge,andtheefficiencyislow(generally,theefficiencyoffullloadoperationisonlyabout80%).Theoverallvolumeisrelativelylargeanditisrelativelyheavy.Andtheinputvoltagerangeisrequiredhigh;andtheswitchingpowersupplyisthehighfrequencyoftheworkState,thesizeofthetransformerisrelativelysmallandrelativelylight,buttheoutputrippleislargerthanthatofalinearpowersupply,butduetoitssimplestructure,lowcostandhighefficiency(theefficiencyofswitchingpowersuppliesonthemarketcanalsoreachmorethan90%)inmanyoccasionsIthasreplacedthelinearpowersupply,whichisthedevelopmenttrendofthepowersupplyinthefuture.
Linearpowersupply,SimplecomparisonofSCRpowersupplyandswitchingpowersupplycircuit
Aboutthecircuitstructure,isitalinearpowersupply,aSCRpowersupplyoraswitch?Thepowersupplydependsonthespecificoccasionandshouldbeusedreasonably.Thesethreekindsofcircuitsarewidelyusedbothathomeandabroad,andeachhasitsowncharacteristics.SCRpowersupply,withitspowerfuloutputpower,makeslinearpowersupplyandswitchingpowersupplyirreplaceable.Linearpowersuppliesarewidelyusedbecauseoftheirhighaccuracyandsuperiorperformance.Switchingpowersupplieshavereducedvolumeandweighttovaryingdegreesduetotheomissionofbulkypowerfrequencytransformers,andarealsowidelyusedinmanysituationswheretheoutputvoltageandoutputcurrentarerelativelystable.
1.Thecircuitstructureofthethyristorpowersupplyisasfollows:
Inlayman’sterms,thethyristorisadevicethatcontrolsthevoltage,becausetheconductionangleofthethyristorcanbeusedControlledbythecircuit,astheoutputvoltageUochanges,theconductionangleofthethyristoralsochanges.ThevoltageUiappliedtotheprimarytransformerofthemaintransformeralsochangesaccordingly.
Thatis,onlypartofthe~220Vmainspowerisaddedtotheprimaryofthemaintransformerafterbeingcontrolledbythethyristor.WhentheoutputvoltageUoishigh,theconductionangleofthethyristorislarge,andmostofthemainsvoltageis"putover"bythethyristor(asshowninFigure1above),sothevoltageappliedtotheprimaryofthetransformer,thatis,Uiisrelativelyhigh.High,ofcoursetheoutputvoltagewillbehigherafterrectificationandfiltering.WhentheoutputvoltageUoisverylow,thethyristorconductionangleisverysmall,andmostofthemainsvoltageis"blocked"bythethyristor(asshowninFigure2below),andonlyaverylowvoltageisappliedtothetransformerTheprimary,thatis,Uiisverylow,andofcoursetheoutputvoltageisverylowafterrectificationandfiltering.
Two.Themaincircuitofthelinearpowersupplyisasfollows:
Thelinearpowersupplyisactuallyahigh-powertriodeconnectedinseriesattheoutputendofthethyristorpowersupply(actuallymultipleonesareconnectedinparallel),andthecontrolcircuitonlyneedstooutputasmallcurrenttoThebaseofthetriodecancontroltheoutputhighcurrentofthetriode,sothatthepowersystemisregulatedagainonthebasisofthethyristorpowersupply.Therefore,thevoltagestabilizationperformanceofthislinearstabilizedpowersupplyisbetterthanthatoftheswitchingpowersupplyorthethyristorpowersupply.1-3ordersofmagnitude.However,thepowertransistor(alsoknownastheregulatortube)generallytakesup10volts,andevery1ampereofoutputcurrentwillconsume10wattsofpowerinsidethepowersupply.Forexample,thelossofa500V5Apowersupplyonthepowertubeis50watts,accountingforthetotaloutput2%ofthepower,sotheefficiencyofthelinearpowersupplyisslightlylowerthanthatofthethyristorpowersupply.
Themaincircuitoftheswitchingpowersupply
Fromthecircuit,itcanbeseenthatthemainspowerbecomes311Vhighvoltageafterrectificationandfiltering,andafterK1~K4powerswitchesworkinorder,itbecomesThepulsesignalisappliedtotheprimaryofthehigh-frequencytransformer,andtheheightofthepulseisalways311V.WhenK1andK4areturnedon,311Vhigh-voltagecurrentflowsintotheprimarytransformerprimarythroughK1intheforwarddirectionandflowsoutthroughK4,formingapositivepulseattheprimarytransformerprimary.Similarly,whenK2andK3areturnedon,311Vhigh-voltagecurrentflowsinreversethroughK3.TheprimarytransformerofthemaintransformerflowsoutthroughK2,andareversepulseisformedattheprimarytransformerofthetransformer.Inthisway,aseriesofforwardandreversepulsesareformedonthesecondarysideofthetransformer,whicharerectifiedandfilteredtoformaDCvoltage.WhentheoutputvoltageUoishigh,thepulsewidthiswide,whentheoutputvoltageUoislow,thepulsewidthisnarrow,sotheswitchtubeisactuallyadevicethatcontrolsthepulsewidth.Inthecaseofnospecialvolumerequirements,linearpowersuppliesaregenerallyused,whicharemainly:
1.Thelinearpowersupplyhasgoodaccuracy(1to3ordersofmagnitudebetterthanswitchingpowersuppliesorthyristorpowersupplies),applicableInmanyoccasions,generaluserswillnotaskquestionsaboutperformance,accuracy,andtechnicalindicators.
2.Itiseasytomaintain,becausemostusershavemaintenancepersonnelwhoarefamiliarwithlinearpowersupplies,andtheyalsohavesparepartsinthisarea.Maintenancetools,amultimetercanbasicallysolvetheproblem,andamorecarefulelectriciancanalsodoit.
3.Aftermaintenance,therearegenerallynosequelae,thefaultcanbecompletelyeliminated,andtheperformancecanbecompletelyrestored.Aslongasthepowersupplyisusedcorrectlyandrepairedintime,itisnotaproblematallforapowersupplyfor10years.
Useoflinearpowersupply
Linearpowersupplyproductscanbewidelyusedinscientificresearch,universities,laboratories,industrialandminingenterprises,electrolysis,electroplating,chargingequipment,etc.
Comparisonofadvantagesanddisadvantages
Theadvantagesoflinearpowersupply:stableperformance,nointerferencesuchashigh-frequencyripple.
Disadvantagesoflinearpowersupply:heatgenerationandlowenergyefficiency.Thereisnosuper-poweredpowersupplytochoosefrom.