CAE Software【Femtet】Murata Software Co., Ltd.
General
Axial gap type motor is analyzed.
Axial gap type motor consists of opposing disc type rotor and stator.
Cogging torque is analyzed which is incurred by the rotor’s rotation while no electricity is applied to the coils.
Analysis function for axial gap motor is applied.
The cogging torque and the magnetic flux density are solved.
Unless specified in the list below, the default conditions will be applied.
Item |
Setting |
Solver |
Magnetic Field Analysis [Luvens] |
Analysis Space |
3D |
Analysis Type |
Transient Analysis |
Unit |
mm |
Options |
Select Rotating Machinery.
[Conversion] Select Partial Model. Number of Divisions of the Whole Model: 4 Select Convert the result to the whole model and output it. |
The Rotating Machinery tab is set as follows.
Tab |
Setting Item |
Setting |
Rotating Machinery |
Rotational Movement |
Select Constant Velocity Number of Rotations: 1800[r/min] Rotor’s Initial Rotation Position: 0[deg] |
Gap Type |
Axial Gap |
|
Number of Slide Mesh Divisions |
Circumferential Division Angle: 1.0[deg] Rotation per Step: 1[mesh] Number of Slide Mesh Layers: 3 |
|
Location of Slide Mesh |
Deselect Automatic calculation Rotor Type: Outer Rotor
[Gap Radius] Inner: 110×10^-3[m] Outer: 112×10^-3[m]
[Gap’s Coordinates in Axial Direction (Z Coordinate)] Top Side of Upper Gap: 52×10^-3[m] Bottom Side of Upper Gap: 50×10^-3[m] Top Side of Lower Gap: -50×10^-3[m] Bottom Side of Lower Gap: -52×10^-3[m]
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Division Size of Slide Mesh in the Axis Direction |
Divide at uniform interval with specified mesh size 10.0[mm] |
Set the Mesh Tab as follows.
Tab |
Setting Item |
Setting |
Mesh |
Meshing Setup |
Automatically set the general mesh size: Deselect General mesh size: 5[mm] |
Ambient Air Creation |
Select Create ambient air automatically Ambient Air Scale: 1.2 |
The Transient Analysis tab is set up as follows.
With the settings as below, number of steps is 90, circumferential division angle is 1.0[deg], and rotation per step is 1[mesh], the rotation up to 90 degrees (=90*1.0*1) is analyzed.
Tab |
Setting Item |
Setting |
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Transient Analysis |
Time step |
Automatic |
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Table |
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A rotor core and coils are placed between stator cores and permanent magnets.
By utilizing the symmetry of the analysis model, it is made to be a quarter model.
“Ambient Air Creation” is selected.
It is assumed that coil1, 2, and 3 are made of fine copper wires which will have little effect of induced current. So, “No” is selected for the Options of Induced Current.
If “Yes” is selected, the loss by induced current will impact the analysis and correct cogging torque will not be obtained.
Body Number/Type |
Body Attribute Name |
Material Name |
34/Solid |
coil1 |
Cu |
35/Solid |
coil2 |
Cu |
36/Solid |
coil3 |
Cu |
33,37,38/Solid |
st_core |
core |
20,31/Solid |
mag1 |
mag |
19,30/Solid |
mag2 |
mag |
23,32/Solid |
rt_core |
core |
The material properties are set up as follows:
Body Attribute Name |
Tab |
Settings |
coil1 |
Current |
Induced current: deselect |
Stator/Rotor/Air |
Stator |
|
coil2 |
Current |
Induced current: deselect |
Stator/Rotor/Air |
Stator |
|
coil3 |
Current |
Induced current: deselect |
Stator/Rotor/Air |
Stator |
|
mag1 |
Direction |
Vector: X=0, Y=0, Z=1 |
Stator/Rotor/Air |
Rotor |
|
mag2 |
Direction |
Vector: X=0, Y=0, Z=-1 |
Stator/Rotor/Air |
Rotor |
|
rt_core |
Stator/Rotor/Air |
Rotor |
st_core |
Stator/Rotor/Air |
Stator |
The material properties are set as follows.
Material Name |
Tab |
Properties |
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Cu |
Conductivity |
Conductivity Type: Conductor Conductivity: 5.977×10^7[S/m] |
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mag |
Relative permeability |
Material Type: Permanent Magnet |
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Magnet |
Magnetization Characteristic Type: Linear Magnetization Strength: 0.5[T] Relative Permeability: 1.05 |
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core |
Permeability |
Magnetization Characteristic Type: Select B-H curve B-H Curve Table
|
Symmetric period boundary is set.
Boundary Condition Name/Topology |
Tab |
Boundary Condition Type |
Settings |
Symmetry |
Symmetry/Continuity |
Periodic |
Rotation Period (1 period) |
The distribution of the magnetic flux density at the rotation angle of 0[deg] is shown below.
The wave of cogging torque is shown as follows.