Fara Dimensiuni Transformator 2D 3D Natasa

8/18/2019 Fara Dimensiuni Transformator 2D 3D Natasa

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7.4

Example(2D/3DTransient)– CoreLoss

7.4-

Maxwell v15

Transformer Core Loss Calculation in Maxwell 2D and 3D

Thisexampleanalyzescoreslossesfora3phpowertransformerhavingalaminatedsteelcoreusingMaxwell2Dand3D.Thetransformerisrated115-

13.8kV,60Hzand30MVA.Thetestedpowerlossesare23,710W.Itisimportant

torealizethatafiniteelementmodelcannotconsiderallofthephysicaland

manufacturingcorelosseffectsinalaminatedcore.Theseeffectsinclude:

mechanicalstressonlaminations,edgeburrlosses,stepgapfringingflux,

circulatingcurrents,variationsinsheetlossvalues,…tonamejustafew.

Becauseofthisthesimulatedcorelossescanbesignificantlydifferentthanthe

testedcorelosses.

Thisexamplewillgothroughallstepstocreatethe2Dand3Dmodelsbasedon

acustomersuppliedbasemodel.Forcorelosses,onlyasinglemagnetizing

windingneedstobeconsidered.Corematerialwillbecharacterizedfornonlinear

BHandcorelosscharacteristics.Anexponentiallyincreasingvoltagesourcewill

beappliedinordertoeliminateinrushcurrentsandtheneedforanunreasonably

longsimulationtime(ofdaysorweeks).Finally,thecorelosswillbeaveraged

overtimeandthecorefluxdensitywillbeviewedinananimatedplot.

Thisexamplewillbesolvedintwopartsusingthe2DTransientand3DTransient

solvers.Themodelconsistsofamagneticcoreandlowvoltagewindingoneach

coreleg.

3D Model 2D Model


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7.4-

Maxwell v15


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7.4


7.4-

Maxwell v15

Launch Maxwell

To access Maxwell

ClicktheMicrosoftStart button,selectPrograms,andselectAnsoft and

thenMaxwell 15.

Opening a New Project

To Open a New Project

AfterlaunchingMaxwell,aprojectwillbeautomaticallycreated.Youcan

alsocreateanewprojectusingbelowoptions.

1. InanMaxwellwindow,clicktheOntheStandardtoolbar,orselectthemenuitemFile > New .

SelectthemenuitemProject > Insert Maxwell 3D Des ign, orclickonthe

icon

Set Solution Type

To Set Solution Type

SelectthemenuitemMaxwell 3D > Solution Type

SolutionTypeWindow:

1. ChooseMagnetic > Transient2. ClicktheOK button


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7.4


7.4-

Maxwell v15

Prepare Geometry

To Import Geometry

SelectthemenuitemModeler > Import

Locatetheparasolid file“Ex_7_4_Core_Loss.x_t”andOpen it.

Thegeometryisofatransformerwithcoresimplifiedinordertoreducethe

complexity.Userscanbringthegeometriesdirectlyanddosimplification

insideMaxwell.

Change Attributes

PressCtrl andselecttheobjectsLV_A, LV_B andLV_C andgoto their

propertieswindow,

1. ChangethecoloroftheobjectstoOrange

2. Changethetransparencyoftheobjectsto0

SelecttheobjectCore fromthehistorytreeandgoto Propertieswindow,

1. Changethetransparencyoftheobjectto0

Specify Excitations

To Create Coil Terminals

PressCtrl andselecttheobjectsLV_A, LV_B andLV_CSelectthemenuitemModeler > Surface Section

InSectionwindow,

1. SectionPlane:SelectXZ

2. PressOK

RenametheresultingsectionstoSectionA, SectionB andSectionC

respectively

SelectthesheetsSectionA, SectionB andSectionC fromthehistorytree

SelectthemenuitemModeler > Boolean > Separate BodiesDeletethesheetsSectionA_Separate1, SectionB_Separate1 and

SectionC_Separate1


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7.4


7.4-

Maxwell v15

Assign Excitations

PressCtrl andselectthesheetsSectionA, SectionB andSectionC fromthe

historytree

SelectthemenuitemMaxwell 3D > Excitations > A ssign > Coil Terminal

InCoilTerminalExcitationwindow,

1. BaseName:term_A

2. NumberofConductors:76

3. PressOK

Thiswillcreatethreeexcitationscorrespondingtoeachsection.Change

theirnamesasbelow:

1. RenametheexcitationcorrespondingtoSectionA asterm_A

2. RenametheexcitationcorrespondingtoSectionB asterm_B

3. RenametheexcitationcorrespondingtoSectionC asterm_C

Create Windings

SelectthemenuitemMaxwell 3D > Excitations > A dd W inding

InWindingwindow,

1. Name:WindingA

2. Type:Voltage

3. Stranded: Checked

4. InitialCurrent:0 A

5. Resistance:1 mOhm

6. Inductance:0 mH (Sincethisiscalculatedbysolver)

7. Voltage: Vpeak* 1-exp -50*time))*cos 2*pi*60*time)

8. PressOK

InAddVariablewindow,

1.

UnitType:Voltage2. Unit:V

3. Value:13800√2/√3= 11268

4. PressOK

Note: Thisisanexponentiallyincreasing(inseveralcycles)sinusoidal60Hzwaveformwithpeakmagnitudeof11,268V..


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7.4


7.4-

Maxwell v15

InSimilarwayaddtwomorewindings

WindingB

1. Name:WindingB

2. Type:Voltage





7. Voltage: Vpeak* 1-exp -50*time))*cos 2*pi*60*time+ 2/3*pi))

WindingC

1. Name:WindingC

2. Type:Voltage





7. Voltage: Vpeak* 1-exp -50*time))*cos 2*pi*60*time+ 4/3*pi))

Add Terminals to Windings

ExpandtheProjectManagertreetoviewExcitations

RightclickonWindingA andselectAdd Terminals

InAddTerminalswindow,

Selectterm_A

PressOK

InSimilarwayaddterm_B toWindingB

Addterm_C toWindingC


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7.4-

Maxwell v15

Assign Materials

To Assign Materials to Coils

PressCtrl andselecttheobjectsLV_A, LV_B andLV_C , rightclickand

selectAssign Material

InSelectDefinitionwindow,

1. Typecopper inSearchbyNamefield

2. PressOK toassignmaterial

To Assign Material to Core

SelecttheobjectCore fromthehistorytree,rightclickandselectAssign

Material

InSelectDefinitionwindow,selectthebuttonAdd Material

InView/EditMaterialwindow,

MaterialName:M125_027

RelativePermeability:

SetthetypetoNonlinear

SelectthebuttonBH Curve fromvaluefield

InBHCurvewindow,

SelectthebuttonImport DatasetSettheFileTypeto*.Tab

LocatethefileEx_7_4_core_loss_B_H.tabandOpen it

PressOK tocloseBHCurvewindow


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Maxwell v15

ReturntoView/EditMaterialwindow,

CoreLossType:SettoElectrical Steel

SetthetabatthebottomofwindowCalculatePropertiesfortoCore

Loss at one Frequency

InBPCurvewindow,

SelectthebuttonImport Dataset

SettheFileTypeto*.Tab

LocatethefileEx_7_4_core_loss_B_loss.tabandOpen it

CoreLossUnit:w/kg

MassDensity:7650 kg/m^3Frequency:60 Hz

Thickness:0.27 mm

Conductivity:5000000 S/m

PressOK tocloseBPCurvewindow


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7.4


7.4-

Maxwell v15

Notethatthecorelosscoefficientsarecalculatedautomatically.

PressOK tocreatethenewmaterial

PressOK tocloseSelectDefinitionwindow

Assign Mesh Operations

Inthetransientsolvers,thereisnoautomaticadaptivemeshing.Therefore,the

usermusteitherlinkthemeshfromanidenticalmodelsolvedusingthe

magnetostatic andeddycurrentsolvers,oralternativelyamanualmeshmustbe

created.Inthisexample,ameshiscreatedmanuallyusing“insideselection”to

createelementsthroughoutthevolumeoftheobjects.

To Assign Mesh Operations for Core

SelecttheobjectCore fromthehistorytreeSelectthemenuitemMaxwell 3D > M esh Operations > Assign > Inside

Selection > Length Based

InElementLengthBasedRefinementwindow,

Name:Length_Core

RestrictLengthofElements: Unchecked

RestricttheNumberofElements: Checked

MaximumNumberofElements:10000

PressOK


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7.4


7.4-1

Maxwell v15

To Assign Mesh Operations for Coils

PressCtrl andselecttheobjectsLV_A, LV_B andLV_C fromthehistory

tree

SelectthemenuitemMaxwell 3D > M esh Operations > Assign > Inside

Selection > Length Based

InElementLengthBasedRefinementwindow,

Name:Length_Coils

RestrictLengthofElements: Unchecked

RestricttheNumberofElements: Checked

MaximumNumberofElements:10000

PressOK

Set Core Loss Calculations

To Set Core Loss calculations for Core

SelectthemenuitemMaxwell 3D > E xcitations > Set Core Loss

InSetCoreLosswindow,

Core:

CoreLossSettings:

Checked

PressOK

Note: Oncethecorelosspropertiesaredefinedinmaterialdefinition,atick

markwillappearinthecolumnDefinedinMaterialindicatingcoreloss

coefficientsarealreadyspecified


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7.4


7.4-1

Maxwell v15

Set Eddy Effects

Sincewindingissingleobjectrepresentingmanystrandsandcoreissingleobjectrepresentingmanylaminations,eddyeffectmustbeturnedoffthem.

To Turn off Eddy Effects in Objects

SelectthemenuitemMaxwell 3D > Excitations > S et Eddy E ffects

InSetEddyEffectswindow,

EnsureEddyEffectsareUnchecked forallobjects

PressOK

Create Simulation Region

To Create Region

SelectthemenuitemDraw > Reg ion

InRegionwindow,

PaddingData:Pad individual directions

+/- X=30

+/- Y=200

+/- Z=30

Note: Thissmallpadding%isacceptableasfieldsarecompletelyconcentratedinsidethemagneticcoreandthereislittleornofringing


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7.4


7.4-1

Maxwell v15

Analysis Setup

To Create Analysis Setup

SelectthemenuitemMaxwell 3D > Analysis Setup > Add Solution Setup

InSolveSetupWindow,

General tab

Stoptime:0.1s

Timestep:0.0005 s

Save Fields tab

Type:Linear Step

Start:0.08 sStop:0.1 s

StepSize:0.0005 s

SelectthebuttonAdd to List >>

Solver tab

NonlinearResiduals:1e-6 (ToProvideaccurateconvergence

forBHCurve

PressOK

Save

To Save File

SelectthemenuitemFile > Save

Savethefilewiththename“Ex_7_4_Core_Loss.mxwl”

Analyze

To Run Solution

SelectthemenuitemMaxwell 3D > A nalyze All


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7.4


7.4-1

Maxwell v15

Create Reports

Plot Winding Currents Vs Time

SelectthemenuitemMaxwell 3D > Results > Create Transient Report >

Rectangular Plot

InReportwindow,

Category:Winding

Quantity:PressCtrl andselectCurrent WindingA),

Current WindingB) andCurrent WindingC)

SelectNew Report

Note: DonotcloseReportwindowaswewillcreatemoreplotsusingsame

window


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7.4


7.4-1

Maxwell v15

Plot Input Voltages Vs Time

InReportwindow,

Quantity

DeselecttheCurrentquantitiesalreadyselected

PressCtrl andselectInputVoltage WindingA),

InputVoltage WindingB) andInputVoltage WindingC)

SelectNew Report

Plot Cores Loss vs Time

InReportwindow,

Category:ChangetoLoss

Quantity:SelectCoreLoss

SelectNew Report

PressClose toclosereportwindow


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7.4


7.4-1

Maxwell v15

Calculate Avg Losses over a Time Range

InXYPlotCorrespondingtoCoreLoss,rightclickontheLegendandselect

Trace Characteristics > Add

InAddTraceCharacteristicswindow,

Category:Math

Function:Avg

ChangetheRangefromFulltoSpecified

StartofRange:80 ms

EndofRange:100 ms

SelectAdd andDone


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7.4


7.4-1

Maxwell v15

Create Flux Density Plot

To Plot Flux Density on Core

DoubleclickonMaxwell3DDesign1 inProjectManagerwindowtoexitPlot

view

SelecttheobjectCore fromthehistorytree

SelectthemenuitemMaxwell 3D > Fields > Fields > B > Mag_B

InCreateFieldPlotwindow,

PlotonsurfaceOnly: Checked

PressDone


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7.4-1

Maxwell v15

To Animate the Plot

SelectthemenuitemMaxwell 3D > F ields > An imate

InSetupAnimationwindow,

SweepVariable:Time

Selectvalues:Selectthetimerangefrom0.0805s to0.087s

PressOK

AnAnimationwindowwillpopupwhichwillenabletostart,stop,pausethe

animation.Animationspeedcanalsobevariedusingsamewindow.The

animationcanbealsoexportedinGIForAVIformatusingExportbutton


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7.4


7.4-1

Maxwell v15

Part 2: 2D Eddy Project

Create a 2D Design Automatically

To Create a 2D Design from 3D

SelectthemenuitemMaxwell 3D > Create D Design

InCreate2DDesignwindow,

CoordinateSystem:Global

SectionPlane:ZX

2DGeometryMode:XY

PressOK

Set Solution Type

To Set Solution Type

SelectthemenuitemMaxwell D > Solution Type

InSolutionTypewindow,

VerifythatGeometryModeissettoCartesian, XYSelecttheradiobuttontoMagnetic > Transient

PressOK

Set Model Depth

Setthedepthofthe2DXYmodeltogivethesameareaasinMaxwell3D=264704mm2.Sincethewidthofthecoreleg=580mm,setthedepth=456mm.

To Set Model Depth

SelectthemenuitemMaxwell D > Model > Set Model Depth

InDesignSettingswindow,

SetModelDepthto456 mm

PressOK


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7.4


7.4-2

Maxwell v15

Modify 2D Geometry

Modify Region

ExpandthehistorytreecorrespondingtothesheetRegion

DoubleclickonthecommandCreateRegion fromthehistorytree

InPropertieswindow,

Change+XPaddingDatato100

Change–XPaddingDatato100

PressOK

Delete Unnecessary Sheets

PressCtrl andselectthesheetsSectionA, SectionB andSectionC

SelectthemenuitemEdit > Delete

Separate Coil Sections

PressCtrl andselectthesheetsLV_A,LV_B andLV_C

SelectthemenuitemModeler > Boolean > Separate Bodies


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7.4


7.4-2

Maxwell v15

Specify Excitations

Assign Coil: Out

PressCtrl andselectthesheetsLV_A, LV_B andLV_C fromhistorytree

SelectthemenuitemMaxwell D > Exc itations > Ass ign > Co il

InCoilExcitationwindow,

BaseName:out

NumberofConductors:76

Polarity:Positive

RenametheexcitationscreatedtoA_out, B_out andC_out

Assign Coil: In

PressCtrl andselectthesheetsLV_A_Separate1, LV_B_Separate1 and

LV_C_Separate1 fromhistorytree

SelectthemenuitemMaxwell D > Exc itations > Ass ign > Co il

InCoilExcitationwindow,

BaseName:in

NumberofConductors:76

Polarity:Negative

RenametheexcitationscreatedtoA_in, B_in andC_inAdd Windings

SelectthemenuitemMaxwell D > Excitations > Add Winding

InWindingwindow,

1. Name:WindingA

2. Type:Voltage





7. Voltage: Vpeak* 1-exp -50*time))*cos 2*pi*60*time)

8. PressOK

InAddVariablewindow,

1. UnitType:Voltage

2. Unit:V

3. Value:13800√2/√3= 11268

4. PressOK


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7.4-2

Maxwell v15

Set Core Loss Calculations

To Set Core Loss calculations for Core

SelectthemenuitemMaxwell D > Excitations > Set Core Loss

InSetCoreLosswindow,

Core:

CoreLossSettings: Checked

PressOK

Analysis Setup

To Create Analysis Setup

SelectthemenuitemMaxwell D > Analysis Setup > Add Solution Setup

InSolveSetupWindow,

General tab

Stoptime:0.1s

Timestep:0.0005 s

Save Fields tab

Type:Linear Step

Start:0.08 s

Stop:0.1 s

StepSize:0.0005 s

SelectthebuttonAdd to List >>

Solver tab

NonlinearResiduals:1e-6

PressOK

Save

To Save File

SelectthemenuitemFile > Save

Analyze

To Run Solution

SelectthemenuitemMaxwell 3D > A nalyze All


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7.4-2

Maxwell v15

Mesh Information

To Plot Mesh on Core and Coils

SelectthemenuitemEdit > Select All Visible

SelectthemenuitemMaxwell D > Fields > Plot Mesh

InCreateMeshPlotwindow,

PressDone

To View Mesh Information

SelectthemenuitemMaxwell D > Results > Solution Data

InSolutionswindow,

SelectthetabMesh Statistics toviewmeshinformation


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7.4-2

Maxwell v15

Create Reports

Plot Winding Currents Vs Time

SelectthemenuitemMaxwell D > Results > Create Transient Report >

Rectangular Plot

InReportwindow,

Category:Winding

Quantity:PressCtrl andselectCurrent WindingA),

Current WindingB) andCurrent WindingC)

SelectNew Report

Note: DonotcloseReportwindowaswewillcreatemoreplotsusingsame

window


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7.4


7.4-2

Maxwell v15

Plot Input Voltages Vs Time

InReportwindow,

Quantity

DeselecttheCurrentquantitiesalreadyselected

PressCtrl andselectInputVoltage WindingA),

InputVoltage WindingB) andInputVoltage WindingC)

SelectNew Report

Plot Cores Loss vs Time

InReportwindow,

Category:ChangetoLoss

Quantity:SelectCoreLoss

SelectNew Report

PressClose toclosereportwindow


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7.4


7.4-2

Maxwell v15

Calculate Avg Losses over a Time Range

InXYPlotCorrespondingtoCoreLoss,rightclickontheLegendandselect

Trace Characteristics > Add

InAddTraceCharacteristicswindow,

Category:Math

Function:Avg

ChangetheRangefromFulltoSpecified

StartofRange:80 ms

EndofRange:100 ms

SelectAdd andDone


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7.4


7.4-2

Maxwell v15

Create Flux Density Plot

To Plot Flux Density on Core

DoubleclickonMaxwell2DDesign1 inProjectManagerwindowtoexitPlot

view

SelectthesheetCore fromthehistorytree

SelectthemenuitemMaxwell D > Fields > Fields > B > Mag_B

InCreateFieldPlotwindow,

PressDone


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Maxwell v15

To Animate the Plot

SelectthemenuitemMaxwell D > Fields > Animate

InSetupAnimationwindow,

SweepVariable:Time

Selectvalues:Selectthetimerangefrom0.0805s to0.087s

PressOK

AnAnimationwindowwillpopupwhichwillenabletostart,stop,pausethe

animation.Animationspeedcanalsobevariedusingsamewindow.The

animationcanbealsoexportedinGIForAVIformatusingExportbutton

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Fara Dimensiuni Transformator 2D 3D Natasa