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: http://www.jmag-international.com/catalog/index.html).
(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 . 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
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[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.
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.