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Winter,2010
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Technical Report Vol.2
A Powerful Simulation Engine
- What Does the JMAG Mesh Generation Engine have to Offer? -
These technical reports introduce the scope of JMAG's technological development.
This edition introduces the value and future of one of the two major foundations
of the simulation engine, the mesh generation engine.
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Optimized Mesh for Analysis of Electromechanical Machines
The JMAG mesh generation engine is for specialized analyses of electromechanical
machines. The mesh is optimized based on the needs of our users.
There is a wide range of phenomena acting on electromechanical devices
from magnetic saturation and the skin effect to electromagnetic induction
and motion. The areas that interest each user differ with the various phenomenon
requiring a unique mesh for each type of analysis. This means that our
users need the ability to generate a wide range of mesh.
A highly accurate mesh can be generated based on the analysis experience
of the user with the universal mesh generation engines that are on the
market today, provided there is enough time. However, the need to be able
to generate a high quality mesh "simply" is huge. CAE is a tool
used to "support" in manufacturing, and is not beneficial unless
it can be used in the design and development process.
The JMAG mesh generation engine specializes in the analysis of electromechanical
machines, requiring no analysis experience and very little time. A mesh
that accurately simulates a wide range of electromagnetic phenomena can
be generated simply. A comparison of eddy current losses obtained by generating
mesh at different resolutions is indicated in Fig. 1. The resolution of
the mesh affects the results that are obtained.
Fig. 1 Comparison of eddy current loss with different resolutions of mesh
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Accuracy and Simplicity is Vital
The mesh generation engine in JMAG that specializes in analyzing electromagnetic
machines focuses on a highly accurate mesh that is simple to generate.
Two areas of development that allows JMAG to enhance the accuracy of the
mesh while making it simpler to generate are outlined below.
(1) Improving accuracy by reducing mesh noise
A high quality of mesh is necessary because a highly accurate cogging torque
analysis is required to further reduce the cogging torque of motors, which
is only approximately 0.1% of the output torque, in addition to reducing
vibration and noise. In this case, the mesh noise affects the analysis
causing inaccurate results.
The JMAG mesh generation engine reduces the mesh noise using noise canceling
technology. The noise canceling technology allows for the cogging torque
to be examined highly accurately without any analysis experience. A comparison
of the cogging torque with and without noise canceling technology is indicated
in Fig. 2. The periodicity and symmetry of the cogging torque waveform
becomes deformed when the mesh noise is not reduced causing inaccurate
analysis results while the accuracy can be maintained when the mesh noise
is reduced.
(2) Automatically generating high quality mesh efficiently
Generating mesh is merely a part of creating a model for an analysis. However,
generating an appropriate mesh necessary to improve the accuracy of an
analysis requires the user understands the electromagnetic phenomena occurring
within machines and has the pertinent analysis experience. The user has
to be capable of automatically generating a high quality mesh efficiently
to obtain accurate results.
The JMAG mesh generation engine is enhancing the automatic mesh generation
function that can generate a high quality mesh using adaptive mesh. Adaptive
mesh generates the optimal mesh for a highly accurate analysis of electromagnetic
phenomena while linking to the JMAG solver in the program.
A high quality mesh can be automatically generated efficiently without
the user being aware of its existence. The Keihin Corporation presented
a hands on example of the automatic mesh generation function for developing
actuators at the JMAG Users Conference 2005.
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