Example2 Vibration Analysis of IPM Motor

General

The vibration of a stator by the electromagnetic force of the IPM motor is analyzed.
Displacement, stress, torque, magnetic flux density, and iron loss are solved.
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.
Unless specified in the list below, the default conditions are applied.

Analysis Condition

Item	Setting
Analysis Space	2D
Thickness in Depth Direction	60[mm]
Unit	mm
Solver	Magnetic Analysis [Luvens]
Analysis Type	Transient Analysis
Analysis Options	Select External Circuit Coupling. Select Rotating machinery. Select Planar Strain. [Reference type of electromagnetic force of the magnetic transient analysis results] Select Value at each step.

The Rotating Machinery tab is set as follows.

Tab

Setting Item

Setting

Rotating Machinery

Rotational Movement

Select Constant Velocity

The Number of Rotations: 1800[r/min]

Rotor’s Initial Rotation Position: 0[deg]

Number of Sliding Mesh Divisions

Circumferential Division Angle: 1.0[deg]

Rotational Quantity per Step: 1[mesh]

Number of Sliding Mesh Layers: 3

External circuit is as follows.

3-phase AC with 60Hz and 5A is applied.

The U phase is calculated with a function to [search for power phase at the maximum torque].

As [Conversion of external circuit I/O values] is ON, the resistance value of the FEM coil is set to the phase resistance which is equivalent to a full model instead of a quarter model.

See [External Circuit Conversion] and [Example of External Circuit Conversion Setup] for the details of conversion.

Set the Mesh Tab as follows.

Tab

Setting Item

Setting

Mesh

Meshing Setup

Set the general mesh size automatically: Deselect

General Mesh size: 1[mm]

Automatic Ambient Air Creation

Select Create ambient air automatically

Ambient Air Scale: 1.2

The Transient Analysis tab is set up as follows.

The number of steps is 90, circumferential division angle is 1.0[deg], and rotational quantity per step is 1[mesh]. The rotation up to 90 degrees (=90*1.0*1) of the mechanical angle is analyzed.

It can be converted to the electric angle of 180[deg] (mechanical angle x number of poles=90*4/2). Half period of the electric angle is analyzed.

As the input power is specified by current, the coil current is in the steady state from the beginning. The torque is also in the steady state.

To calculate the iron loss, it is necessary to set the timesteps for one period of electric angle in the steady state, and to define the iron loss characteristic for the material property.

Tab

Setting Item

Setting

Transient Analysis

Timestep

Automatic

Table

Number	Calculation steps	Output interval
1	90	1

Model

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

The motor has 4 poles and 24 slots.

This is a 2D model analysis.

The stress analysis is performed on the stator domain only. The rotational displacement around the stator is fixed by the boundary condition [Fix].

Generally, if only magnetic analysis is executed, a period-symmetric model is used which utilizes the symmetry of the model as in Example 1 of magnetic transient analysis.
In this example, however, a full model is used because a periodic boundary is not supported in the stress analysis.

Body Attributes and Materials

Body Number/Type	Body Attribute Name	Material Name
14/Sheet	Mag1	NMX-S43SH_Hitachi Metal*
15/Sheet	Mag2	NMX-S43SH_Hitachi Metal*
63/Sheet	Mag3	NMX-S43SH_Hitachi Metal*
62/Sheet	Mag4	NMX-S43SH_Hitachi Metal*
66/Sheet	Rotor	35JN270_JFE Steel*
65/Sheet	Stator	35JN270_JFE Steel*
37/Sheet	U1+	008_Cu *
38/Sheet	U1+	008_Cu *
39/Sheet	W1-	008_Cu *
40/Sheet	W1-	008_Cu *
41/Sheet	V1+	008_Cu *
42/Sheet	V1+	008_Cu *
43/Sheet	U1-	008_Cu *
44/Sheet	U1-	008_Cu *
45/Sheet	W1+	008_Cu *
46/Sheet	W1+	008_Cu *
47/Sheet	V1-	008_Cu *
48/Sheet	V1-	008_Cu *

* Available from the material DB

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
	Current	Click Yes for induced current setting.
	Stator/Rotor/Air	Rotor
	Analysis Domain	Deselect Stress Analysis.
Mag2	Direction	Vector: X=1, Y=0, Z=-1
	Current	Click Yes for induced current setting.
	Stator/Rotor/Air	Rotor
	Analysis Domain	Deselect Stress Analysis.
Mag3	Direction	Vector: X=-1, Y=0, Z=-1
	Current	Click Yes for induced current setting.
	Stator/Rotor/Air	Rotor
	Analysis Domain	Deselect Stress Analysis.
Mag4	Direction	Vector: X=-1, Y=0, Z=1
	Current	Click Yes for induced current setting.
	Stator/Rotor/Air	Rotor
	Analysis Domain	Deselect Stress Analysis.
Rotor	Layer	Select Take layer into account Space: 97[%] Layer direction vector: X=0, Y=1, Z=0
	Stator/Rotor/Air	Rotor
	Analysis Domain	Deselect Stress Analysis.
Stator	Layer	Select Take layer into account Space: 97[%] Layer direction vector: X=0, Y=1, Z=0
Stator	Stator/Rotor/Air	Stator
U1+	Current	Waveform: External circuit coupling Coil name on the circuit: U1 Turns: 35[Turns] Direction: +Y direction
U1+	Stator/Rotor/Air	Stator
V1+	Current	Waveform: External circuit coupling Coil name on the circuit: V1 Turns: 35[Turns] Direction: +Y direction
V1+	Stator/Rotor/Air	Stator
W1-	Current	Waveform: External circuit coupling Coil name on the circuit: W1 Turns: 35[Turns] Direction: – Y direction
W1-	Stator/Rotor/Air	Stator
U1-	Current	Waveform: External circuit coupling Coil name on the circuit: U1 Turns: 35[Turns] Direction: – Y direction
U1-	Stator/Rotor/Air	Stator
V1-	Current	Waveform: External circuit coupling Coil name on the circuit: V1 Turns: 35[Turns] Direction: – Y direction
V1-	Stator/Rotor/Air	Stator
W1+	Current	Waveform: External circuit coupling Coil name on the circuit: W1 Turns: 35[Turns] Direction: +Y direction
W1+	Stator/Rotor/Air	Stator