JMAG has powerful features for coupling the electromagnetic field analysis with circuit, thermal, and structural analyses.

To fully capture the complex phenomena occurring in an electric device, it is important to carefully consider all the assumptions that will be made in the model. A coupled analysis allows the complex phenomenon to be accurately represented for a thorough simulation

Coupling with a Circuit

When analyzing an electric device, the power supply or controller that drives the device cannot be separated from the device. JMAG offers features for coupling the magnetic field and the circuit for simultaneous simulation using the built in circuit simulator. JMAG can also be linked to some standard circuit/control simulation software such as MATLAB/Simulink and PSIM.

PWM power supply circuit

Magnetic flux density distribution of a linear motor

Thermal Analysis

JMAG's thermal analysis capability allows the coupling of the magnetic field analysis with a thermal analysis with eddy currents, iron loss and coil joule losses as heat sources. The magnetic field analysis can also include the temperature-varying properties of magnetic materials and conductors for a full 2-way coupling.

Example 1:
The design of an induction heating system for high frequency quenching needs a coupled electromagnetic field and thermal analysis to show the temperature distribution inside the heated object and the time history of the temperature.

Example 2:
Temperature control is critical for electric devices like motors. A thermal analysis allows you to view the heat generation and temperature distribution caused by coil current, iron loss, and eddy currents in the magnet.

High-frequency induction heating analysis of a crankshaft

Temperature variation after the motor starts running.

Coupling with Structural Analysis

JMAG’s structural analysis solver takes as input the electromagnetic force calculated from the electromagnetic field analysis to determine the stress distribution, vibration, and radiated sound distribution. JMAG also supports the use of the stress distribution in the electromagnetic analysis to determine the stress-dependent magnetization properties of materials.

Example 1:
The centrifugal force on the rotor of an IPM motor may cause structural problems. With JMAG, an analysis that includes the adhesion and contact of the magnet and rotor core as well as the stress of the bridge can be performed.

Example 2:
Motors are widely used in various applications that require smaller and lighter motors along with the reduction of vibration and noise. JMAG can be used to analyze vibration and radiation sound caused by slot harmonics and the inverter drive.

Stress analysis

Displacement depending on the degree of adhesion of the magnet

Compressive stress depending on the degree of adhesion of the magnet

Sound pressure analysis

Magnetic flux density distribution of a speaker

Sound pressure distribution of a speaker

JMAG has a large material database with a wide range of data provided by the leading material manufacturers. This data can be used directly in the simulations. JMAG supports advanced material modeling including anisotropy, temperature dependency, minor loop, magnetization, and demagnetization.

Material Database

The material database contains more than 700 data items for electromagnetic steel sheet, soft magnetic composite, and the permanent magnets, made by 12 manufactures. User-defined properties are also available.

Electromagnetic Steel Sheet

• 80 products available. The magnetization and loss properties are available for most of the materials.
• Lamination structure modeling, calculation with the lamination factor.
• Accurate modeling for loss calculation.
• Both oriented and non-oriented steel sheet.
• Stress dependence supported.

Eddy current distribution at the edge of the motor, taking into account the laminated structure.

Core Material

• The major core materials including ferrite and soft magnetic composite are available.

Ferrite and soft magnetic composite are available in the material database.

Magnet

• The demagnetization properties can be defined either from the material database or as used defined parameters. All typical magnetization patterns are available in JMAG. You can specify a pattern by selecting it from the list. Skew and step skew can be specified.
• Temperature dependence is supported.
• Magnetization analysis for analyzing the effects of both complete and incomplete magnetization.
• Demagnetization analysis for analyzing the effects of heat or a demagnetizing field.

Magnetization direction ( r ) component contour plot

Cogging torque with/without skew

The accuracy of a finite element analysis is strongly linked to the quality of the mesh. JMAG’s robust automatic meshing capabilities allow you to control the mesh pattern and element size to suit the analysis. Automatic Mesh The Automatic Mesh feature recognizes the model shape and gaps and automatically generates a high-quality mesh over the entire model including the surrounding air region and air gaps. The adaptive mesh feature uses simulation results to control the mesh size to provide a more optimal mesh. Mesh generated in the model and in the air region Specifying the Element Size The element size can be specified at vertices, edges, faces, and in regions allowing for a large degree of control over the mesh to maintain the accuracy of the analysis while using the minimum number of elements. Element size of the face Element size of the part Slide Mesh Option The rotation or translation motion of a motor can be accounted for by using a sliding mesh interface. On the interface the mesh is automatically created to have regular intervals reducing or eliminating mesh-related errors. Slide mesh modeling the rotation motion Slide mesh modeling the translation motion Layered Mesh For detailed modeling of laminated materials a layered mesh can be generated parallel to a specified solid face. Skin Mesh To include the skin effect accurately the mesh needs to have elements which are smaller than the skin depth at the surface of regions containing eddy currents. An optimal mesh can be generated by specifying the face and the size.

The goal of the analysis is to provide feedback to the design process for further improvement. To do so, it is important to extract as much valuable information from the analysis results as possible.

JMAG offers many options in the postprocessor, including contour and vector plots, animation, multiple cutting planes, graphs and tables, to support evaluation of the results from various angles.

Postprocessor

Magnetic flux lines of the SPM motor	Eddy current density distribution of the magnet(2D)	Eddy current density distribution of the magnet(3D)
Magnetic flux density distribution of the IPM motor	Magnetic flux density distribution of the alternator	Magnetic flux density distribution vector plot of the speed sensor

Inverter circuit and current waveform	Graphs of the induction motor (torque waveform, secondary current waveform, table)

Graph

Loss Calculation Tool

Inductance Calculation Tool

	Dependency of inductance on the current

Acoustic Analysis

Evaluate the radiated sound pressure around the speaker by the contour plot.