1、9.14Topic 2D Boundary ConditionsAssigning Boundary Conditions Boundary Conditions Boundary conditions enable you to control the characteristics of planes, faces, or interfaces between objects. Boundary conditions are important to understand and are fundamental to solution of Maxwells equations. Purp

2、ose of the Exercise This exercise introduces various boundary conditions used in Maxwell 2D based on a simple example with coils and steel core. The user will learn how to use Vector Potential, Balloon, Symmetry and Matching Boundary (Master and Slave). Ansoft Maxwell Design Environment The followin

3、g features of the Ansoft Maxwell Design Environment are used to create the models covered in this topic 2D Sheet Modeling User Defined Primitives (UDPs): SRMCore Boolean Operations: Separate Bodies Boundaries/Excitations Current: Stranded Boundaries: Vector Potential, Balloon, Symmetry, Master/Slave

4、, Analysis Magnetostatic Field Overlays: H Vector 9.14-17 Ansoft Maxwell Field Simulator V12 Users Guide Summary of eight designs to be simulated 2_Balloon 1_VectorPotential 4_Symmetry_Odd and 6_NoSymmetry 3_Balloon_ChangeExcitation5_Symmetry_Even 7_Matching_Positive8_Matching_Negative Getting Start

5、ed Launching Maxwell To access Maxwell, click the Microsoft Start button, select Programs, and select Ansoft and then Maxwell 12. Or double click th e icon on the desktop. Setting Tool Options To set the tool options: Note: In order to follow the steps outlined in this example, verify that the follo

6、wing tool options are set : 1. Select the menu item Tools Options Maxwell 2D Options 2. Maxwell Options Window: 1. Click the General Options tab Use Wizards for data entry when creating new boundaries: ; Checked Duplicate boundaries with geometry: ; Checked 2. Click the OK button 3. Select the menu

7、item Tools Options Modeler Options. 4. 3D Modeler Options Window: 1. Click the Operation tab Automatically cover closed polylines: ; Checked 2. Click the Drawing tab Edit property of new primitives: ; Checked 3. Click the OK button Opening a New Project To open a new project: 1. In an Maxwell window

8、, click theon the Standard toolbar, or select the menu item File New. 2. Select the menu item Project Insert Maxwell 2D Design, or click on the icon. 3. Save the project with name “Ex_9_14_BasicBoundaryCondictions” to your own folder. Change the name of the design from “Maxwell2DDesign1” to “1_Vecto

9、rPotential”. Set Solution Type Select the menu item: Maxwell 2D Solution Type Magnetostatic, or right mouse click on 1_VectorPotential and select Solution Type. The Geometry Mode should be: Cartesian, XY Creating 2D Model The example that will be used to demonstrate how to assign boundary conditions

10、 does not represent any real-world product. The intent of this write-up is rather to demonstrate how boundary conditions are implemented. Set Model Units Select the menu item Modeler Units Select Units: mm (millimeters) Create Stator and Coils: A User Defined Primitive will be used to create the Sta

11、tor and Coils Draw User Defined Primitive Syslib Rmxprt SRMCore Use the values given in the panel below to create the Stator and Coils Click on the object just created in the drawing window and in the panel on the left change its name from SRMCore1 to Stator. Change the Material from vacuum to nicke

12、l. The stator and coils were created as one entity and they need to be separated. 1. Click on the Stator-Coil group so that they are selected 2. Select the menu item Modeler Boolean Separate Bodies, the result will be a single stator and eight coil cross-sections. As was done with the Stator, change

13、 the name, materials, and color for Coils. The material property for the Stator will be nickel, and the material property for the Coils will be copper. The name and color for each object is given below. Coil3Coil2 Coil1 Coil4 Coil5 Coil6 Coil7 Coil8 Stator Assign Current Source to Coils Select all e

14、ight coils by holding down the CTRL key and using your mouse or selecting from tree on the left hand side of the GUI Select the menu item Maxwell 2D Excitations Assign Current or right click Assign Excitations Current 1. Change the Base Name to Current 2. Change the value to 100 Amps The project tre

15、e now shows eight separate Excitations, each of them is pointing out of the plane (along Z axis): Changing directions of Excitations Right click on Excitations List , hold down CTRL key and select Current_2, Current_4, Current_6 and Current_8, then click on “Properties”, change direction from Positi

16、ve to Negative. Create the Problem Region One of the main differences between Maxwell V11 and V12 is that a Background Region is not automatically created when a project is started. A separate object needs to be specifically created. To create a rectangular region simply select Draw Region, or click

17、 the icon from standard toolbar. The size of this rectangular region is based on dimensions of the existing objects. Change Padding Percentage to 20. Click View Fit All All Views, or CTRL + D. Create an Analysis Setup Select the menu item Maxwell 2D Analysis Setup Add Solution Setup or right click o

18、n the Analysis in the project window Add Solution Setup Select General and verify the setting as follows Select Convergence and verify the setting as follows Set up Boundary Conditions Select the menu item Edit Select Edges or right click in the Modeler Select Edges Select outer edge of the Stator C

19、lick on the menu item Maxwell 2D Boundaries Assign Vector Potential Accpet the default value and OK. Save the Project Select the menu item File Save Check the Validity of the Model Select the menu item Maxwell Validation Check, or click on the icon The problem wont solve unless each item has a check

20、 mark. Analyze Select the menu item Maxwell 2D Analyze All, or click on theicon Solution Data To view the Solution Data, select the menu item Maxwell 2D Results Solution Data, or right click on Setup1 under Analysis Convergence Here you can view the Profile and the Convergence. Note: The default vie

21、w for convergence is Table. Click on the Plot radio button to view a graphical representations of the convergence data. Note: You dont have to wait for the solution to be done to do this. You can do this while the simulation is running, all information will update automatically after each pass is do

22、ne. Plot Mesh, H-Field Vector and Flux Line Click on the menu item Edit Select All Visible or Select All, or use CTRL + A , or select everything from the history tree window, then right mouse click in the modeler and select Plot Mesh . Do the same, select all objects, then right mouse click in the m

23、odeler and select Fields H H_Vector, and Fields A Flux Lines . The following H-field vector plot will appear, which is the result of the current excitation on the left side. If the plot is not as nice as you may want to see, you can double click on the legend bar, then change various settings under

24、Color map / Scale / Marker / Arrow or Plots tabs. Create Design2: 2_Balloon Click on design 1_VectorPotential in the Project Manager window and then right mouse click and select Copy Click on the project name Ex_9_14_Basic_BoundaryConditions, right click and select Paste, a new design called 1_Vecto

25、rPotential1 has been created, change the design name to 2_Balloon. Click on VectorPotential1 under Boundaries in the Project Manager, and press “Delete” from keyboard to remove the boundary condition. Right click in the modeler and select Select Edges, to change from object selection mode to edge se

26、lection mode. Left mouse click on one of the edges of the Region, then right mouse click and select All Object Edges to select all edges of the Region. Right mouse click again, Assign Boundary Balloon Run the simulation and compare H Field plot with the previous design that has vector potential boun

27、dary. Balloon on all edges of the RegionZero Vector Potential on the outer edge of the Stator Create Design3: 3_Balloon_ChangeExcitation Click on design 2_Balloon in the Project Manager window and then right mouse click and select Copy Click on the project name Ex_9_14_Basic_BoundaryConditions, righ

28、t click and select Paste, a new design called 2_Balloon1 has been created, change the design name to 3_Balloon_ChangeExcitation. Modify Current Excitation Click on Excitations Current_3 in the Project window, you will see a Properties window under Project window, change from Positive to Negative in

29、the Direction row. Also, Change Current_7 from Positive to Negative Change Current_4 and Current_8 from Negative to Positive. The purpose is to change the current excitation as shown in the graph below. Current_3Current_2Current_4Current_1Current_5Current_8Current_6Current_7Current_1 Positive Curren

30、t_2 Negative Current_3 Negative Current_4 Positive Current_5 Positive Current_6 Negative Current_7 Negative Current_8 Positive Run the simulation and compare H Field plot with Design2 2_Balloon that has different excitations. Design2: 2_BalloonDesign3: 3_Balloon_ChangeExcitation 9.14Topic 2D Boundar

31、y Conditions Symmetry Boundary Create Design4: 4_Symmetry_Odd Click on design 2_Balloon in the Project Manager window and then right mouse click and select Copy Click on the project name Ex_9_14_Basic_BoundaryConditions, right click and select Paste, a new design called 2_Balloon1 has been created,

32、change the design name to 4_Symmetry_Odd. Select all objects and right mouse click in the modeler Boolean Split, choose XZ plane to create half geometry. In the history tree, double click on CreateRegion under Vacuum Region, change Y Padding Percentage to 0. Remove the Balloon boundary, reassign the

33、 Balloon boundary to three edges (not on the symmetry edge). Change to Edge selection mode and click on the edge of the Region along X axis, right mouse click in the modeler Assign Boundary Symmetry, choose Odd (Flux Tangential). 9.14-20 Ansoft Maxwell Field Simulator V12 Users Guide Symmetry: Odd (

34、Flux Tangential) Run simulation and view results. Create Design5: 5_Symmetry_Even Click on design 4_Symmetry_Odd in the Project Manager window and then right mouse click and select Copy Click on the project name Ex_9_14_Basic_BoundaryConditions, right click and select Paste, a new design called 4_Sy

35、mmetry_Odd1 has been created, change the design name to 5_Symmetry_Even. Symmetry: Even (Flux Normal)Select the Symmetry boundary and change it to Even (Flux Normal). Run simulation and view results. 9.14Topic 2D Boundary ConditionsCreate Design6: 6_NoSymmetry Click on design 4_Symmetry_Odd in the P

36、roject Manager window and then right mouse click and select Copy Click on the project name Ex_9_14_Basic_BoundaryConditions, right click and select Paste, a new design called 4_Symmetry_Odd1 has been created, change the design name to 6_NoSymmetry. Select the Symmetry boundary and delete it. Run sim

37、ulation and view results. No Symmetry: by default an Odd (Flux Tangential boundary is assigned) The result should look the same as Design4: 4_Symmetry_Odd because odd symmetry or flux tangential is the default boundary condition. 9.14-24 Ansoft Maxwell Field Simulator V12 Users Guide Matching Bounda

38、ries (Master/Slave). Design2: 2_BalloonDesign3: 3_Balloon_ChangeExcitation Design7: 7_Matching_PositiveDesign8: 8_Matching_Negative Slave=MasterSlave= Master MasterMaster Matching Boundaries: Master/Slave Create Design7: 7_Matching_Positive Click on design 6_NoSymmetry in the Project Manager window and then right mouse click and select Copy. Click on the project name Ex_9_14_Basic_BoundaryConditions, right click and select Paste, a new design called 6_NoSymmetry1 has been created, change the design name to 7_Matching_Positive. Select all objects and right mouse click in the modeler Edit Bool