电池参数设置.docx
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电池参数设置
Description
TheBatteryblockimplementsagenericdynamicmodelparameterizedtorepresentmostpopulartypesofrechargeablebatteries.
Theequivalentcircuitofthebatteryisshownbelow:
Lead-AcidModel
Dischargemodel(i*>0)
f1(it,i∗,i,Exp)=E0−K⋅QQ−it⋅i∗−K⋅QQ−it⋅it+Laplace−1(Exp(s)Sel(s)⋅0).
ChargeModel(i*<0)
f2(it,i∗,i,Exp)=E0−K⋅Qit+⋅Q⋅i∗−K⋅QQ−it⋅it+Laplace−1(Exp(s)Sel(s)⋅1s).
Lithium-IonModel
DischargeModel(i*>0)
f1(it,i∗,i)=E0−K⋅QQ−it⋅i∗−K⋅QQ−it⋅it+A⋅exp(−B⋅it).
ChargeModel(i*<0)
f2(it,i∗,i)=E0−K⋅Qit+⋅Q⋅i∗−K⋅QQ−it⋅it+A⋅exp(−B⋅it).
Nickel-CadmiumandNickel-Metal-HydrideModel
DischargeModel(i*>0)
f1(it,i∗,i,Exp)=E0−K⋅QQ−it⋅i∗−K⋅QQ−it⋅it+Laplace−1(Exp(s)Sel(s)⋅0).
ChargeModel(i*<0)
f2(it,i∗,i,Exp)=E0−K⋅Qit+⋅Q⋅i∗−K⋅QQ−it⋅it+Laplace−1(Exp(s)Sel(s)⋅1s),
where,
EBatt =Nonlinearvoltage(V)
E0 =Constantvoltage(V)
Exp(s) =Exponentialzonedynamics(V)
Sel(s) =Representsthebatterymode.Sel(s)=0duringbatterydischarge,Sel(s)=1duringbatterycharging.
K=Polarizationconstant(Ah−1)orPolarizationresistance(Ohms)
i*=Lowfrequencycurrentdynamics(A)
i=Batterycurrent(A)
it=Extractedcapacity(Ah)
Q=Maximumbatterycapacity(Ah)
A=Exponentialvoltage(V)
B=Exponentialcapacity(Ah)−1
Theparametersoftheequivalentcircuitcanbemodifiedtorepresentaparticularbatterytype,basedonitsdischargecharacteristics.Atypicaldischargecurveiscomposedofthreesections,asshowninthenextfigure:
Thefirstsectionrepresentstheexponentialvoltagedropwhenthebatteryischarged.Dependingonthebatterytype,thisareaismoreorlesswide.Thesecondsectionrepresentsthechargethatcanbeextractedfromthebatteryuntilthevoltagedropsbelowthebatterynominalvoltage.Finally,thethirdsectionrepresentsthetotaldischargeofthebattery,whenthevoltagedropsrapidly.
Whenthebatterycurrentisnegative,thebatterywillrechargefollowingachargecharacteristicasshownbelow:
Notethattheparametersofthemodelarededucedfromdischargecharacteristicsandassumedtobethesameforcharging.
TheExp(s)transferfunctionrepresentsthehysteresisphenomenonfortheLead-Acid,NiCDandNiMHbatteriesduringchargeanddischargecycles.Theexponentialvoltageincreaseswhenbatteryischarging,nomattertheSOCofthebattery.Whenthebatteryisdischarging,theexponentialvoltagedecreasesimmediately:
DialogBoxandParameters
ParametersTab
Batterytype
Providesasetofpredeterminedchargebehaviorforfourtypesofbattery:
Lead-Acid
Lithium-Ion
Nickel-Cadmium
Nickel-Metal-Hydride
NominalVoltage(V)
Thenominalvoltage(Vnom)ofthebattery(volts).Thenominalvoltagerepresentstheendofthelinearzoneofthedischargecharacteristics.
RatedCapacity(Ah)
Theratedcapacity(Qrated)ofthebatteryinampere-hour.Theratedcapacityistheminimumeffectivecapacityofthebattery.
InitialState-Of-Charge(%)
TheinitialState-Of-Charge(SOC)ofthebattery.100%indicatesafullychargedbatteryand0%indicatesanemptybattery.Thisparameterisusedasaninitialconditionforthesimulationanddoesnotaffectthedischargecurve(whentheoption PlotDischargeCharacteristics isused).
UseparametersbasedonBatterytypeandnominalvalues
Loadthecorrespondingparametersintheentriesofthedialogbox,dependingontheselected Batterytype,the NominalVoltage andthe RatedCapacity.
Whenapresetmodelisused,thedetailedparameterscannotbemodified.Ifyouwanttomodifythedischargecurve,selectthedesiredbatterytypetoloadthedefaultparameters,andthenuncheckthe UseparametersbasedonBatterytypeandnominalvalues checkboxtoaccessthedetailedparameters.
MaximumCapacity(Ah)
Themaximumtheoreticalcapacity(Q),whenadiscontinuityoccursinthebatteryvoltage.Thisvalueisgenerallyequalto105%oftheratedcapacity.
FullychargedVoltage(V)
Thefullychargedvoltage(Vfull),foragivendischargecurrent.Notethatthefullychargedvoltageisnottheno-loadvoltage.
NominalDischargeCurrent(A)
Thenominaldischargecurrent,forwhichthedischargecurvehasbeenmeasured.Forexample,atypicaldischargecurrentforaAhNiMHbatteryis20%oftheratedcapacity:
*Ah/1h=.
InternalResistance
Theinternalresistanceofthebattery(ohms).Whenapresetmodelisused,agenericvalueisloaded,correspondingto1%ofthenominalpower(nominalvoltage*ratedcapacityofthebattery).Theresistanceissupposedtobeconstantduringthechargeandthedischargecyclesanddoesnotvarywiththeamplitudeofthecurrent.
Capacity(Ah)@NominalVoltage
Thecapacity(Qnom)extractedfromthebatteryuntilthevoltagedropsunderthenominalvoltage.Thisvalueshouldbebetween Qexp and Qmax.
Exponentialzone[Voltage(V),Capacity(Ah)]
Thevoltage(Vexp)andthecapacity(Qexp)correspondingtotheendoftheexponentialzone.Thevoltageshouldbebetween Vnom and Vfull.Thecapacityshouldbebetween0andQnom.
ViewDischargeCharacteristicsTab
PlotDischargeCharacteristics
Clicktoplotafigurecontainingtwographs.Thefirstgraphrepresentsthenominaldischargecurve(atthe NominalDischargeCurrent)andthesecondgraphrepresentsthedischargecurvesatthespecifieddischargecurrents.
Dischargecurrent
Allowstospecifydifferentvaluesofdischargecurrent.Thedischargecharacteristicsforthesecurrentsarepresentedinthesecondpartofthegraph.
Units
Chooseeither Time or Ampere-hour asthe x-axisfortheplot.
BatteryDynamicsTab
Batteryresponsetime(s)
Theresponsetimeofthebattery(at95%ofthefinalvalue).
Thisvaluerepresentsthevoltagedynamicsandcanbeobservedwhenacurrentstepisapplied:
Inthisexample,abatteryresponsetimeof30secsisused.
ExtractBatteryParametersFromDataSheets
ThissectiongivesanexampleofdetailedparametersextractedfromthePanasonicNiMH-HHR650Dbatterydatasheet:
Fromthespecificationtables,weobtaintheratedcapacityandtheinternalresistance.TheotherdetailedparametersarededucedfromtheTypicalDischargeCharacteristicsplot:
Parameter
Value
Ratedcapacity
Ah
InternalResistance
2mΩ
NominalVoltage (a)
V
RatedCapacity
Ah
MaximumCapacity (b)
7Ah*
FullyChargedvoltage (c)
V
NominalDischargeCurrent (d)
A
Capacity@NominalVoltage (a)
Ah
ExponentialVoltage (e)
V
ExponentialCapacity (e)
Ah
Theseparametersareapproximateanddependontheprecisionofthepointsobtainedfromthedischargecurve.Atool,calledScanIt(providedbyamsterCHEM,canbeusedtoextractvaluesfromdatasheetcurves.
TheparametersobtainedfromthedatasheetareenteredinthemaskoftheBatteryblockasinthefollowingpicture:
Thedischargecurves(thedottedlinecurvesinthefollowingplots)obtainedwiththeseparametersaresimilartothedatasheetcurves.
CellsinSeriesand/orinParallel
Tomodelaseriesand/orparallelcombinationofcellsbasedontheparametersofasinglecell,theparametertransformationshowninthenextfigurecanbeused.The Nb_ser variableinmaskbelowcorrespondstothenumberofcellsinseries,and Nb_par correspondstothenumberofcellinparallel:
BlockInputsandOutputs
m
TheSimulinkoutputoftheblockisavectorcontainingthreesignals.YoucandemultiplexthesesignalsbyusingtheBusSelectorblockprovidedintheSimulinklibrary.
Signal
Definition
Units
SOC
TheState-Of-Chargeofthebattery(between0and100%).TheSOCforafullychargedbatteryis100%andforanemptybatteryis0%.TheSOCiscalculatedas:
SOC=100(1−1Qt0i(t) dt).
%
Current
TheBatterycurrent
A
Voltage
TheBatteryvoltage
V
ModelValidation
Experimentalvalidationofthemodelshownamaximumerrorof5%(whenSOCisbetween10%and100%)forcharge(currentbetween0and2C)anddischarge(currentbetween0and5C)dynamics.
ModelAssumptions
Theinternalresistanceissupposedconstantduringthechargeandthedischargecyclesanddoesn'tvarywiththeamplitudeofthecurrent.
Theparametersofthemodelarededucedfromdischargecharacteristicsandassumedtobethesameforcharging.
Thecapacityofthebatterydoesn'tchangewiththeamplitudeofcurrent(NoPeukerteffect).
Themodeldoesn'ttakethetemperatureintoaccount.
TheSelf-Dischargeofthebatteryisnotrepresented.Itcanberepresentedbyaddingalargeresistanceinparallelwiththebatteryterminals.
Thebatteryhasnomemoryeffect.
Limitations
Theminimumno-loadbatteryvoltageis0voltandthemaximumbatteryvoltageisequalto2*E0.
Theminimumcapacityofthebatteryis0AhandthemaximumcapacityisQmax.
Example
The power_battery exampleillustratesa200volts,AhNiMHbatteryconnectedtoaconstantloadof50A.TheDCmachineisconnectedinparallelwiththeloadandoperatesatnoloadtorque.WhentheState-Of-Charge(SOC)ofthebatterygoesunder(40%),anegativeloadtorqueof200Nmisappliedtothemachinesoitactsasageneratortorechargethebattery.WhentheSOCgoesover80%,theloadtorqueisremovedsoonlythebatterysuppliesthe50ampsload.
Thesimulationproducesthefollowingsresults:
ThebatteryisdischargedbytheconstantDCloadof50A.WhentheSOCdropsunder,amechanicaltorqueof−200Nmisappliedsothemachineactsasageneratorandprovidesacurrentof100amps.Hence,50ampsgoestotheloadand50ampsgoestorechargethebattery.WhentheSOCgoesover,themechanicaltorqueisremovedandthemachineoperatesfreely.Andthenthecyclerestarts.
References
[1]Tremblay,O.,Dessaint,."ExperimentalValidationofaBatteryDynamicModelforEVApplications."WorldElectricVehi