Motor Development Using JMAG

Contribution of JMAG

The areas and cause of losses that are difficult to measure using actual experiments on prototypes can be identified using JMAG. This section introduces the reasons why JMAG is selected by designers. The actual methods for performing analyses are presented in our Application Catalog (hereinafter referred to as JAC:

(1) Material Modeling Combining Convenience and Flexibility
Highly accurate modeling is required to obtain highly accurate analysis results. Material modeling is one of the most vital elements to obtaining loss [15][16]. JMAG contains material data for over 700 materials from 12 different manufacturers. The material characteristics can be modeled without specifying any complex settings by simply dragging and dropping the desired material from a list of materials to the model. Iron loss analyses accounting for stress dependency can be performed with ease using the wide range of materials registered in JMAG's material database that includes the magnetic flux density and stress dependency of iron loss.
Each of the material settings can also be specified by the user. The settings can be specified as desired so that even the measured data of iron loss can only be used for an analysis utilizing the material database in JMAG as a base.

Joule loss frequency components of a rotor core

Joule loss frequency components of a rotor core

Iron loss density distribution

Iron loss density distribution
(left: not accounting for stress; right: accounting for stress)

(2) Calculation Features for Obtaining Various Loss
The eddy currents and hysteresis loss which cause the iron loss can be obtained separately using the iron loss calculation features in JMAG (iron loss condition/iron loss study)[JAC069] [JAC106]. Highly accurate results are obtained using calculations that account for the nonlinear properties of materials. Especially in eddy current calculations[JAC022], the surface layers of a model can be comprehensively analyzed using mesh simulating the skin effect which accounts for the skin depth. The efficiency can be examined using the loss that is obtained[JAC058] [JAC103]. In addition, loss accounting for the carrier harmonics in the actual drive, such as inverters, can be obtained using features to link to circuit/control simulators[30][31][32][JAC090] [JAC059]. The link to the circuit/control simulator is not only used to analyze the current waveform during drive, but also examine the control system on the circuit side. Some case studies have even shown a reduction in loss by optimizing the excitation timing in SR motors[33].
In JMAG, the stress distribution obtained using a structural analysis can be set as a condition for the magnetic field analysis. A magnetic field analysis which takes into account the stress dependency of the permeability and loss can be performed by obtaining the stress distribution produced by shrink fitting and press fitting first in a structural analysis[JAC87] [JAC142].
Furthermore, the loss obtained in a magnetic field analysis can be specified as a condition in a thermal analysis[JAC018] Therefore, the rising temperature of the motor during drive can be investigated in addition to identifying the heat sources. The effects of thermal demagnetization of magnets caused by rising temperatures can also be investigated[JAC120].

(3) Visualizing Results in Versatile Post-processing
The quality of analysis is determined by its ability to extract valuable information from the results. JMAG offers versatile post-processing that supports the evaluation of analysis results from a wide-range of perspectives. The flow of eddy currents can be comprehensively displayed in the model using a multiple cut plane feature and the magnetic flux versus time can be displayed for particular points on a model using the probe feature. The magnetic flux pathways can also be displayed three dimensionally using flux lines. The graph feature can even be used to extract the loss versus time or the frequency components using FFT with ease.

This Technical Report has discussed the challenges of motor development as well as energy conservation, looked at ways of achieving higher efficiency, and introduced how JMAG is being used.
The next technical report will focus on attaining lower vibration and lower noise as well as reducing cost.


  1. Implementing JMAG Meidensha Corporation     2. Motor Development Using JMAG
  3. JMAG Application Catalog
[Iron Loss Analysis of an IPM Motor]   [Thermal Demagnetization Analysis of an SPM Motor]
  4. Exhibition Report - TECHNO-FRONTIER 2010 -

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