Example7 Torque Analysis of IPM Motor (Current Source)

General

  • Torque characteristics of IPM motor (Interior Permanent Magnet Motor) is analyzed when the electricity is applied.
    The model is a permanent magnet synchronous motor with magnets built in a rotor.

  • The form of model is same as Exercise 1, but the three-phase AC source is used in the external circuit.
    (Exercise 1 uses the three-phase AC voltage source.)

  • The analysis is coupled with the external circuit.

  • The homogenizing method is applied to simulate the layer structure of the electromagnetic plates of steel for the core.

  • The torque and the magnetic flux density are solved.
     

  • Unless specified in the list below, the default conditions will be applied.
     

  • In this exercise, the model is half period symmetric for your easy understanding.
    Fast calculation is possible by making this model 1/4 period symmetric.
    Obtain the project file of 1/4 period symmetric model. (Save the project file before open)

Analysis Conditions

Item

Setting

Solver

Magnetic Field Analysis [Luvens]

Analysis Space

2D

Analysis Type

Transient Analysis

Unit

mm

Options

Select External Circuit Coupling.

Select Rotating machinery.

 

[Conversion]

Model Thickness: 30×10^-3[m]

Select Partial Model.

Number of Divisions of the Whole Model: 2

Circuit Configuration Number of Series: 1

Circuit Configuration Number of parallels: 2

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]

Number of Slide Mesh Divisions

Circumferential Division Angle: 1.0[deg]

Rotation per Step: 1[mesh]

Number of Slide Mesh Layers: 3

 

External circuit is as follows.

60[Hz] three-phase AC is applied.

 

Set the Mesh Tab as follows.

Tab

Setting Item

Setting

Mesh

Meshing Setup

Automatically set the general mesh size: Deselect

General mesh size: 1[mm]

Ambient Air Creation

Select Create ambient air automatically

Ambient Air Scale: 1.2

 

The Transient Analysis tab is set up as follows.

The umber of steps is 180, circumferential division angle is 1.0[deg], and rotation per step is 1[mesh]. The rotation up to 180 degrees (=180*1.0*1) is analyzed.

Tab

Setting Item

Setting

Transient Analysis

Time step

Automatic

Table

Number

Calculation steps

Output steps

1

180

1

 

Graphical Objects

A rotor core and magnet are placed in the center. A stator and coils are placed around them.

The motor has 4 poles.

This is a 2D model analysis. By utilizing the symmetry of the analysis model, it is made to be a half period symmetric model.

Rotation period boundary (symmetric) is set.

“Ambient Air Creation” is selected.

  • In this exercise, the model is half period symmetric for your easy understanding. Fast calculation is possible by making this model 1/4 period symmetric.
    In the quarter model, the number of series in the circuit is 2 and the resistance value of FEM coil in the external circuit is half of the half model.

Body Attributes and Materials

Body Number/Type

Body Attribute Name

Material Name

14/Sheet

Mag1

mag

15/Sheet

Mag2

mag

13/Sheet

Rotor

core

37/Sheet

Stator

core

39/Sheet

U1+

Cu

40/Sheet

U1+

Cu

41/Sheet

W1-

Cu

42/Sheet

W1-

Cu

43/Sheet

V1+

Cu

44/Sheet

V1+

Cu

45/Sheet

U1-

Cu

46/Sheet

U1-

Cu

47/Sheet

W1+

Cu

48/Sheet

W1+

Cu

49/Sheet

V1-

Cu

50/Sheet

V1-

Cu

 

The body attribute is set up as follows.

For the core, the homogenizing method is selected to simulate the layered steel plates.

Body Attribute Name

Tab

Setting

Mag1

Direction

Vector: X=1, Y=0, Z=1

Stator/Rotor/Air

Rotor

Mag2

Direction

Vector: X=1, Y=0, Z=-1

Stator/Rotor/Air

Rotor

Rotor

Layer

Select Take layer into account

Space: 97[%]

Layer direction vector: X=0, Y=1, Z=0

Stator/Rotor/Air

Rotor

Stator

Layer

Select Take layer into account

Space: 97[%]

Layer direction vector: X=0, Y=1, Z=0

Stator/Rotor/Air

Stator

U1-

Current

Waveform: External circuit coupling

Coil name on the circuit: U1

Turns: 35[Turns]

Direction: – Y direction

Stator/Rotor/Air

Stator

U1+

Current

Waveform: External circuit coupling

Coil name on the circuit: U1

Turns: 35[Turns]

Direction: +Y direction

Stator/Rotor/Air

Stator

V1-

Current

Waveform: External circuit coupling

Coil name on the circuit: V1

Turns: 35[Turns]

Direction: – Y direction

Stator/Rotor/Air

Stator

V1+

Current

Waveform: External circuit coupling

Coil name on the circuit: V1

Turns: 35[Turns]

Direction: +Y direction

Stator/Rotor/Air

Stator

W1-

Current

Waveform: External Circuit Coupling

Coil name on the circuit: W1

Turns: 35[Turns]

Direction: – Y direction

Stator/Rotor/Air

Stator

W1+

Current

Waveform: External circuit coupling

Coil name on the circuit: W1

Turns: 35[Turns]

Direction: +Y direction

Stator/Rotor/Air

Stator

 

The material properties are set as follows.

Material Name

Tab

Properties

Cu

Conductivity

Conductivity Type: Conductor

Conductivity: 5.977×10^7[S/m]

mag

Permeability

Material Type: Permanent magnet

Magnet

Magnetization Characteristic Type: Linear

Magnetization Strength: 1.25

Relative Permeability: 1.05

core

Permeability

Magnetization Characteristic Type: Select B-H curve

B-H Curve Table

Magnetic Field [A/m]

Magnetic Flux Density [T]

0

0

58

0.42

90

0.8

180

1.19

380

1.37

1100

1.48

2000

1.55

3000

1.608

11000

1.81

20000

1.91

 

Boundary Condition

Half period symmetric boundary is set.

Boundary Condition Name/Topology

Tab

Boundary Condition Type

Setting

Symmetric

Symmetry/Continuity

Periodic

Rotation Period (1 period)

Results

The distribution of the magnetic flux density at the rotation angle of 0[deg] is shown below.

 

The diagram below shows time-torque characteristics.

About 20[N*m] of torque is obtained.