Home / Examples / Magnetic Analysis (Luvens, Transient Analysis) / Example 5: Power Generation of IMP Generator

Example 5: Power Generation of IMP Generator

General

Power generation of IPM generator is analyzed.
The power is generated in the coils of the stator by the rotor's rotation.
The model is a permanent magnet synchronous generator with magnets built in the rotor.
The current generated by the rotor's rotation is calculated.
The analysis coupled with the external circuit is performed.
The current and the magnetic flux density are solved.
Unless specified in the list below, the default conditions will be applied.

Results will vary depending on Femtet version and the PC environment.

Analysis Conditions

Item	Settings
Analysis Space	2D
Thickness in Depth Direction	30 [mm]
Unit	mm
Solver	Magnetic Analysis [Luvens]
Analysis Type	Transient Analysis
Options	Select External Circuit Coupling. Select Rotating Machinery. [Partial Model (Symmetric Model) Setting] Select Partial Model. Division Number: 2 [Conversion of External Circuit I/O Values] Select Convert Number of Series: 1 Number of Parallels: 2 Select Convert results to full model for output

The Rotating Machinery tab is set as follows.

Tab

Setting Item

Settings

Rotating Machinery

Rotational Move

Select Constant Velocity

Number of Rotations: 3000 [r/min]

Rotor’s Initial Rotation Position: 0 [deg]

Number of Sliding Mesh Divisions

Circumferential Division Angle: 1.0 [deg]

Rotational Quantity per Step: 3 [meshes]

Number of Sliding Mesh Layers: 3

External circuit is as follows.

[R1] is a resistor to detect the generated power. It is placed where a battery is supposed to be placed.

Its value is set to be small enough, 0.001 [Ohm], for the battery's internal resistance.

Set the Mesh Tab as follows.

Tab

Setting Item

Settings

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: 1.25

The Transient Analysis tab is set up as follows.

The umber of calculation steps is 180, circumferential division angle is 1.0[deg], and rotational quantity per step is 3 [mesh]. The rotation up to 540 degrees (=180*1.0*3) is analyzed.

Tab

Setting Item

Settings

Transient Analysis

Timestep

Automatic

Table

Number	Calculation Steps	Output Interval
1	180	1

Model

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

This is a 2D analysis of a symmetric half model.

Half period rotation boundary (symmetry) is set.

[Ambient Air Creation] is selected.

Body Attributes and Materials

Body Number/Type	Body Attribute Name	Material Name
6/Sheet	Mag1	mag
7/Sheet	Mag2	mag
5/Sheet	Rotor	core
20/Sheet	Stator	core
22/Sheet	U1+	Cu
21/Sheet	W1-	Cu
25/Sheet	V1+	Cu
23/Sheet	U1-	Cu
26/Sheet	W1+	Cu
24/Sheet	V1-	Cu

The body attribute is set up as follows.

Body Attribute Name	Tab	Settings
Mag1	Direction	Vector: X=1, Y=0, Z=1
Mag1	Stator/Rotor/Air	Rotor
Mag2	Direction	Vector: X=1, Y=0, Z=-1
Mag2	Stator/Rotor/Air	Rotor
Rotor	Stator/Rotor/Air	Rotor
Stator	Stator/Rotor/Air	Stator
U1-	Current	Waveform: External Circuit Coupling Coil Name on the Circuit: U1 Turns: 15 [Turns] Direction: -Y Direction
U1-	Stator/Rotor/Air	Stator
U1+	Current	Waveform: External Circuit Coupling Coil name on the circuit: U1 Turns: 15[Turns] Direction: +Y Direction
U1+	Stator/Rotor/Air	Stator
V1-	Current	Waveform: External Circuit Coupling Coil Name on the Circuit: V1 Turns: 15 [Turns] Direction: -Y Direction
V1-	Stator/Rotor/Air	Stator
V1+	Current	Waveform: External Circuit Coupling Coil Name on the Circuit: V1 Turns: 15 [Turns] Direction: +Y Direction
V1+	Stator/Rotor/Air	Stator
W1-	Current	Waveform: External Circuit Coupling Coil Name on the Circuit: W1 Turns: 15 [Turns] Direction: -Y Direction
W1-	Stator/Rotor/Air	Stator
W1+	Current	Waveform: External Circuit Coupling Coil Name on the Circuit: W1 Turns: 15 [Turns] Direction: +Y Direction
W1+	Stator/Rotor/Air	Stator

The material properties are set as follows.

Material Name

Tab

Properties

Conductivity

Conductivity Type: Conductor

Conductivity: 5.977x107 [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
80000	2.15

Boundary Conditions

One period symmetric boundary is set.

Boundary Condition Name/Topology	Tab	Boundary Condition Type	Settings
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.

In the result table, the generated current is output as the circuit current of the resistor, which is for detecting the generated power.

The diagram below is time-generated current characteristic.

The generated power is about 155 [A] on average of the current in the steady state.