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第1页原文Title：RAPIDCHARGESYSTEMFORLEAD-ACIDBATTERYOFSOLARENERGYSTREETLIGHTBASEDONSINGLE-CHIPMICROCOMPUTER1.IntroductionOurcountryisveryrichinsolarenergyresourcesandtheutilizationofsolarenergyheatisoneofthetechnologiesthatareofthehighestcommercialdegreeandthemostuniversalapplicationinnewandrenewableenergyresources.Undertheinitiativeofbuildingsavingsociety,thesolarenergyelectro-opticilluminationisourcountry'srealisticchoiceundertheexistingnationalconditionanditreducestheexpendituresofmunicipaladministrationonstreetlamptoacertainextent.Especiallyinthenewly-builturbanroadsectionandremoteborderdistrictthathasdifficultyinusingelectricity,itisofthestrongestpromotionandistakenseriouslybyFinancedepartment;itishonoredasthe21stcentury'sgreenproject.2.ThebasictheoryofbatterychargingInthemid-1960s,AmericanscientistMashasdonethemassiveexperimentalstudytothecharging-upprocessofringentaccumulatorcell,andproposedacceptablechargingcurvetakenbytheaccumulatorbythelowestgasefficiencyforpremise,thecurvefunctionisiifthechargingcurrentchangesaccordingtothiscurve,itmayreducethedurationofcharginggreatly,andhasnotaffectonbattery'scapacityanditslife,thusithadestablishedresearchdirectiontothemethodofthefastcharging.iscalledthecurvethebestchargepatterninprinciple.ItMayseethattheinitialchargingcurrentisverybigfromtheMascurve,butweakensveryquickly.Theprimarycauseisthatitcomesintobeingthephenomenonofpolarizationduringtheprocessofcharging.Thephenomenonofpolarizationisreferstothattheinteriorthesealedaccumulatorhasproducedtheoxygenandthehydrogenduringitsprocessofcharging,whentheoxygencannotbeabsorbedpromptly,thenitpilesuponthepositiveplate,enlargethepressureoftheinteriorofbattery,thebattery’stemperaturerises,reducespositiveplate'sareasimultaneously,performancebytheincreaseofinteriorresistance.Thepolarizationcanaffectthespeedandthequalityofcharging,andevenreducethelifeofaccumulator.Therefore,it’simportanttodevelopfastchargesystemofbatterywhoseperformanceisfineandmovementisreliable.ByNotaffectingtheservicelifeofaccumulatorasfaraspossibleforpremise,ithopedthatitcanfillthebatterycapacitysufficientlyadopting第2页thebiggestchargingcurrentinashorttime,andthebatteryneitherproducestoomuchgasesnorcausestheinteriorhyperpyrexiaduringtheprocess.3.SolarstreetlightsystemInthesolarstreetlightsystem,accumulator’schargingsourceisfromthesolarcell,thechangeofclimateandtheuser'sexcessiveusingelectricityareveryeasytocausetheaccumulatorover-discharge,andthereforethenormalwork'sguaranteerateofthesolarstreetlightislowerthanthesituationofalternatingcurrentbyfar.IftheLead-acidbatteryisinthestateofover-dischargeduringuseprocess,thentheaccumulator'slifewillreducegreatly.Otherwise,iftheaccumulatorcellhasbeenintheuseprocessfloatsthechargeortheshallowdischargecondition,thenaccumulatorcell'sservicelifewilllengthengreatly,evenlengthenonemoretime.Therefore,thefunctionofthecharginganddischargingcontrolsystemisobviousinthestreetlightsystemmerelyreliesonthesolarcellforthebatterycharging,itsperformancehasdecidedaccumulator'sperformance,system'sreliabilityandsystem'scostdirectly.3.1pulsechargingmethodThetheoreticalbaseofpulsefastchargemethodisbysuperimposingcertainfrequency,widthandhighnegativepulseormidwaystopsforashorttimeduringthecharge,makestheleadionparticipatesintheresponseproducePbbydissolvingPbS04andPbO2withenoughtimeandenhancesitsdensity,alsomakestheprocreantH+andHS04-ionputasidewithenoughtimefromthesurfaceofelectrode.Itssyntheticaleffectistoreducethepolarizationoftheaccumulator'sconcentration,permittoenlargethechargingcurrent,reducethechargingtime.Becausethephenomenonofpolarizationisoftennotobviousduringtheinitialperiodofcharging,itmayadoptbigelectriccurrent0.8~1timeofratedcapacitytocarryontheconstant-currentcharge,makestheaccumulatorchargingattaintothe50%~60%ratedcapacityinashorttime.Stoptochargewhenthesinglestandardvoltageofaccumulatorrisesto2.4V,thewaterstartstodecomposeandmicroairemits(aboutis25milliseconds).Inordertoeliminatetheelectricchargeaccumulationoftheelectrochemistrypolarizationandthegaswhichformsintheporeofpoleplate,afterstoppingsufficiently,Makingtheaccumulatorthroughonebigcurrentpulsewhosedirectionisoppositetochargebydischargingafterstoppingcharging,thenstops(about40milliseconds)chargingagain,thedepthofpulseis第3页1.5~3timesofchargingcurrent,thepulsewidthis150~1000microseconds.Thelatercharging-upprocessfollowsthiscyclicuntilsufficiently.Thismaymakethespeedofpolarizationreduceobviously,thussolvestheproblemofaccumulator’slifeinfluencedbyfast-charge.3.2mastercontrollerP87LPC767Thecontrolloopstillconsumesaccumulator’senergyaftercontrolcircuitcuttingoffload’sreturnrouteandthereforethecontrolloopmustreducetheelectroniccomponenttoreducethepowerlostasfaraspossible.Stemmingfromthisintention,thiselectriccircuittakesmicrocontrollerP87LPC767ofPHILIPSasCPU.Thismicrocontrollersuitsformanysituationsrequestinghighdensity,lowcost,particularlyitspowerlossisonly0.44mA~1.7mAwhenitworksround100kHz~4MHz,thesupplyvoltageis3.3V,that’sverysuitableforpowersupplysystemofaccumulator.P87LPC7