Cogging Torque of Stepper Motorexamples|products|Murata Software Co., Ltd.

Example35 Cogging Torque of Stepper Motor

General

  • The cogging torque of a stepper motor is analyzed.
     

  • The relationship between the rotor angle and the torque is calculated with the motor rotation analysis function.
    See [Motor Rotation Analysis] for the detail.
     

  • Please be aware that this is a static analysis. The transient phenomena (dynamic magnetic field) is not analyzed.
    The coupled analysis with the external circuit cannot be performed either.
    If you want to analyze the transient phenomena or perform the coupled analysis with the external circuit, use the transient analysis (Luvens).
     

  • The torque curve and the magnetic flux density vectors are solved.
     

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

 

Analysis Space

Item

Settings

Analysis Space

3D

Model unit

mm

Analysis Conditions

Item

Settings

Solvers

Magnetic Field Analysis [Gauss]

Analysis Type

Static analysis

Options

Select “Calculate the torque”

 

Set the Torque Calculation tab as follows.

Tab

Setting Item

Settings

Torque Calculation

Coordinates on Center Axis:

X=0, Y=0, Z=0

Vectors of the Axis

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

 

Set the Mesh Tab as follows.

Tab

Setting Item

Settings

Mesh

Meshing Setup

Automatically set the general mesh size: Deselect

General mesh size: 3[mm]

Model

A stator and coils are placed in the air.

A magnet (rotor) is set in the center and its center is the rotation axis of the motor.

No current is flowing in coils.

Body Attributes and Materials

Body Number/Type

Body Attribute Name

Material Name

19/Solid

Rotor

Mag

12/Solid

Shaft

SM

14/Solid

Stator

SM

25/Solid

Coil

008_Cu *

26/Solid

Coil

008_Cu *

27/Solid

Coil

008_Cu *

28/Solid

Coil

008_Cu *

* Available from the Material DB

 

The magnetizing direction of Rotor is set as follows.

Body Attribute Name

Tab

Settings

Rotor

Direction

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

 

The material properties are set up as follows:

Material Name

Tab

Properties

SM

Permeability

Relative Permeability 3000

Mag

Permeability

Material Type: Permanent Magnet

Magnet

Magnetization Strength: 1

Boundary Conditions

No setting.

Motor Rotation Analysis

Tab

Item

Setting

Rotation Setting

Select the Bodies to Rotate

Rotor

Shaft

Rotation Angles

Start angle: 0[deg]

Stop angle: 360[deg]

Step angle: 30[deg]

 

  • Values for each variable can be set for each rotational angle on the variable setting tab.
    The coil current can be set for each rotational angle.

Results

On the [Model] tab,

click ▼ at the bottom of [Run Mesher/Solver] and click [Motor Rotation Analysis] .

Click [Start Calc] to start the calculation.

 

The result is output by csv format.

 

In the figure below, the horizontal coordinate is rotational angle, and the vertical coordinate is torque.