JMAG Newsletter July,2013Product Report

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Introducing JMAG-Designer Ver.12.1

We released JMAG-Designer Ver.12.1 in June, 2013. A wide variety of new functions have been added, including pre- and post-processing, solvers, and coupling, and the product now boasts greater stability and ease of use with better loss analysis accuracy and new tools for MBD, linking functions, and geometry editor functions.
This article introduces the most important new functions in Ver.12.1, focusing on loss analysis, MBD, and geometry creation.

Overview

This Product Report introduces fifteen functions that have been added to Ver. 12.1, with an explanation of their development background and goals, dividing Ver. 12.1's functions into seven categories.

Materials Modeling and Loss Analysis

To raise the efficiency of devices, particularly motors, to the upper limit, materials modeling and loss analysis technologies for simulation are needed beyond what has been available in the past.
Our new materials modeling and loss analysis functions share the goals of more directly handling hysteresis properties and eddy currents in laminated steel sheet to be closer to actual phenomena, and of improved accuracy in the high-frequency region of areas with high saturation and silicon sheet.
Also, it is now possible in analysis to specify areas of deterioration from warping when dealing with degradation of magnetic properties due to punching.

Advanced Iron Loss Calculation

In past versions of JMAG, loss calculation was carried out by obtaining the coefficients needed for hysteresis loss and eddy current loss calculation formulas from magnetic flux density distributions, using magnetic field analysis and loss data for each frequency in post-processing.
In Ver.12.1, a new method has been developed that provides accuracy across a wider range of frequencies and magnetic flux densities than was possible before, by directly handling the core's hysteresis properties and electric conductivity.

1. Hysteresis Loss Calculation
For hysteresis loss calculation, it is now possible to define hysteresis loops directly from the new GUI, in addition to the calculation methods that were already available (fig. 1).
The properties of materials with BH characteristics and loss data already in the materials database can be analyzed by automatically generating hysteresis loops from their DC magnetizing properties.
Even if the amplitude of the magnetic flux density is the same, loss calculation can be done reflecting differences in loss due to the location of the minor loops by directly accounting for hysteresis properties (fig. 2). Compared with previous calculation methods, accuracy for hysteresis loss is greatly improved in high-saturation regions with superimposed direct current or with high-frequency components superimposed over a fundamental wave.

Fig. 1 Specifying hysteresis loops from the GUI
Fig. 1 Specifying hysteresis loops from the GUI

Fig. 2 Difference in minor loop location with the same amplitude (left) and difference between previous and new hysteresis loss analysis methods (right)
Fig. 2 Difference in minor loop location with the same amplitude (left) and difference between previous and new hysteresis loss analysis methods (right)

2. Eddy Current Loss Calculation
For eddy current loss analysis, a new calculation method has been introduced that uses the lamination loss function included in Ver.12 in iron loss calculations. This method, in contrast to previous calculations that were based on loss data tables per frequency, runs analysis accounting for the thickness of each lamination of steel sheet based on the specified electric conductivity. Eddy current loss calculation accounting for laminated construction is also made possible for 2D models by considering the results from solving Maxwell's equations in the lamination direction as corrections to 2D analyses. Accuracy for eddy current loss values, which previously had a tendency toward overestimation particularly in high-frequency regions, has been greatly improved because it is no longer necessary to apply extrapolation/interpolation processing when analysis frequencies are outside the range of a loss data table.

Fig. 3 Eddy current loss from lamination loss
Fig. 3 Eddy current loss from lamination loss

Modeling Accounting for Degradation

JMAG provides methods for mapping stress distributions or multiplying total applied BH characteristics by a scale factor in order to model magnetization properties due to production degradation.
Newly-added analysis functions that account for processing stress allow analysis with direct specification of regions that are degraded due to processing. Degraded regions are specified by selecting the region edges for 2D models or solid faces for 3D models, and specifying the amount of deformation (fig. 4).
Changes in properties due to processing deformation are specified in a magnetic flux density - magnetization correction coefficient table for magnetic properties, and in a magnetic flux density - loss correction table for loss properties.
Increases in iron loss density adjacent to the punching region can be confirmed by comparing the iron loss density distributions with and without processing degradation around the teeth and slots (fig. 5).

Fig. 4 Specifying the degraded region in a 2D model.
Fig. 4 Specifying the degraded region in a 2D model.

Fig. 5 Comparing iron loss density distributions with and without degradation(left: without degradation; right: with degradation in the slots)
Fig. 5 Comparing iron loss density distributions with and without degradation
(left: without degradation; right: with degradation in the slots)

JMAG-RT

JMAG-RT's utility has been broadened for HILS in addition to SILS/MILS. With the increase in applications that operate JMAG-RT and their further establishment in business, demand has risen for reduced RT model generation time and for more targets for using JMAG-RT. In Ver.12.1, needs for versatile control simulation have been met with reduced RT model generation time, support for parallel circuits, and improved precision for JMAG-RT Viewer, with a particular focus on work efficiency.

Reduced RT Model Generation Time

RT model generation time has been greatly reduced by focusing on symmetry in geometries and periodicity in three-phase AC in order to reduce the number of calculation cases. Further, we plan to accelerate nonlinear iterative calculation in magnetic field calculations carried out during RT model generation by providing specialized tunings for JMAG-RT. Table 1 shows a comparison of RT model generation time between Ver.12.1 and the previous version.

Table 1 Comparison of RT model generation time between old and new versions.
Table 1 Comparison of RT model generation time between old and new versions.

Support for Parallel Circuits

Up to now, motor models in JMAG-RT were provided with the assumption that their FEM coil circuits were constructed in series. When the target's circuit was parallel, circuit conversion processing was necessary for correction before and after generating an RT model.
Ver.12.1 makes it easier and cheaper, with corrective processing no longer necessary because parallel circuits can be accounted for during RT model generation (fig. 6). Circulating current is not considered in each parallel circuit, so m-series/n-parallel structures and n-parallel/m-series structures are seen as equivalent.

Fig. 6 RT model parallel circuit structures supported in Ver.12.1
Fig. 6 RT model parallel circuit structures supported in Ver.12.1

JMAG RT-Viewer for Spatial Harmonics Models

Spatial harmonics models not only reflect nonlinear properties of magnetization characteristics in inductance and amount of magnetic flux, but also provide precise data reflecting the spatial harmonics of slot harmonics and others. By reflecting these precise RT models in JMAG-RT Viewer, it is now possible to provide more accurate torque-rotation speed properties and efficiency maps (fig. 7).

Fig. 7 Comparison of rotation speed-torque properties for each calculation method
Fig. 7 Comparison of rotation speed-torque properties for each calculation method

Model Based Design and Multi-physics

For model based design using finite element method electromagnetic field analysis (hereafter FEA), interactive data exchange of results as load conditions is necessary, in addition to creation of analysis models based on the physical phenomena from one CAD model.
Ver.12.1 accelerates model based design by improving multipurpose file output functions and including a new user interface for Abaqus CSE.

Multi-Purpose File Export Tool

This tool was first included in Ver.12, allowing JMAG analysis results together with mesh generated in JMAG to be output in Nastran format.
In Ver.12.1, in addition to the earlier functionality, mesh data created in other applications in Nastran format can be imported, and physical quantities including electromagnetic force and loss calculated in JMAG can be mapped onto mesh data as load conditions.
Further, thermal transfer coefficient distributions that are output in CSV format can be imported into JMAG thermal transfer analysis data from analysis results of other thermo-hydrodynamic software and set as thermal transfer boundary conditions. When the temperature dependency of a thermal transfer boundary condition is small, analysis results can be obtained in a short time by using JMAG's thermal transfer analysis.

GUI for Abaqus CSE

CSE in Abaqus is a function that controls coupled analysis with Abaqus and other software. Processing with input from the command line or patch files is necessary for coupled analysis using CSE.
In Ver.12.1, a JMAG GUI is included for coupled analysis with JMAG (fig. 8). This provides an easy-to-use environment for JMAG-Abaqus coupled analysis.

Fig. 8 GUI for Abaqus interface
Fig. 8 GUI for Abaqus interface

Transformer Analysis

Higher and higher frequencies are being used for the drive frequency in small-scale power transformers in order to reduce their size even more. These higher frequencies lead to problems such as increased loss and localized heat generation because of skin effects and proximity effects in the windings. In order to reduce loss and localized heat generation, the use of litz wire has increased, and therefore so has the need for analysis that accounts for litz wire.

Improved Litz Wire Calculation

The number of litz wires per bundle that can be used and the solving speed in analysis within transformer studies have been greatly increased (fig. 9).
It is not unusual for the number of strands in a litz wire bundle to be more than 100, but investigation using transformer studies is made possible by the great increase in calculating ability.

Fig. 9 Litz wire analysis (left), and solving speed comparison between versions (right)
Fig. 9 Litz wire analysis (left), and solving speed comparison between versions (right)

Mesh Functions

The expanded slide mesh functions released in Ver.12 have been extended further. The application range and calculation speed for expanded slide mesh have been greatly improved over the previous version.

Improved Expanded Slide Mesh

The new expanded slide mesh functions are a combination of earlier functions and extruded mesh functions (fig. 10). Higher calculation speeds can be achieved with reduced model scale, while maintaining calculation precision. Table 2 is a comparison of number of elements and calculation time with the previous version. Expanded slide mesh functions can also be applied to full models. (Ver. 12 only supported partial models)

Fig. 10 Differences in mesh with the same model
Fig. 10 Differences in mesh with the same model

Table 2 Comparison of model scale and analysis time
Table 2 Comparison of model scale and analysis time

Pre- and Post-Processing

Pre- and post-processing functions have been added to enable users' ease-of-use, work efficiency, and detailed analysis, including: conversion of 2D models to 3D models while preserving materials and conditions; improved set functions; and optimization functions focusing on specified components with FFT processing.

Conversion from 2D Models to 3D Models

This is a function for simple creation of 3D models by using extrusion operations on already-existing 2D models. Materials and conditions are preserved, so analysis can be done immediately after conversion to a 3D model (fig. 11). It is convenient when, after 2D analysis, you want to run detailed analysis considering 3D effects. For example, models created in JMAG-Express can be easily expanded into 3D models.

Fig. 11 Conversion into a 3D model by extrusion and preservation of materials and conditions
Fig. 11 Conversion into a 3D model by extrusion and preservation of materials and conditions

Improved Set Functions

Analysis templates are a very convenient functionality for taking the settings, conditions, and results processing from one analysis model and applying them to other analysis models. Until now, if an analysis template was applied to a CAD model without set information, the problem arose that the analysis template's information was lost.
With new set functions, when an analysis template is applied to a CAD model without set information, an empty set is created in the CAD model. This greatly reduces the work of resetting set information because the user can easily see what kind of solid/surface/edge information should be set for the empty set.

FFT Data for Optimization

For analysis using optimization, it is necessary to record output values for target functions in response graphs. In Ver.12, users' output table values could be recorded as response graphs, but table values processed using FFT after analysis were not supported.
Measures dealing with certain frequencies, for example reducing noise in the audible range, are needed in actual design. Optimization calculation, such as to control only specific frequencies in a waveform processed with FFT, is necessary in carrying out analysis for this purpose.
With new response graph functions, FFT results can be used in optimization calculations by recording table values processed with FFT as response values. Fig. 12 shows results from an example with target functions set to maximize the first-order component and minimize the 3rd-order component of a motor's induced voltage. With the flux-barrier shape as a design variable, the induced voltage and the 3rd-order component of the magnetic flux density are displayed with the geometry for each case.

Fig. 12 Comparison of distribution of 3rd-order component of magnetic flux density (above), and induced voltage (below) for each case
Fig. 12 Comparison of distribution of 3rd-order component of magnetic flux density (above), and induced voltage (below) for each case

Flux-Line Drawing for 3D Models

In addition to previously-available functions for drawing flux lines from a coordinate point specified on a model, it is now possible draw 3D flux lines passing through a specified cross-section (fig. 13). By drawing vector fields such as magnetic flux density and current density as continuous flow lines, the analysis target's physical phenomena can be obtained objectively as electromagnetic circuits or electric circuits.

Fig. 13 Current density distribution (left) and flux line distribution (right) of a ring coil and conductor sheet model
Fig. 13 Current density distribution (left) and flux line distribution (right) of a ring coil and conductor sheet model

Geometry Editor

As mentioned at the beginning of this article, geometry creation functions in Ver.12.1 have been developed with the goals of high stability and ease-of-use.
For optimization calculations and parametric analyses combining multiple design variables, a high degree of robustness in constraint conditions is desirable for the various geometries that arise in the calculation process. New constraint functions have improved robustness to meet these demands.
Also, the Geometry Editor employs functions to improve ease-of-use at various points. The Geometry Editor now allows you to check interference, display previews during constraint setting, set features together for assembly models, and select targets according to setting targets of basic shapes/constraints/regions.

Improved Robustness for Constraint Functions

Improved algorithms have led to a great improvement in robustness for constraint functions. Angle constraints have been particularly strengthened for better robustness.
Also, other constraint condition functions now make it possible to confirm constraints in advance via a preview. Constraints can be confirmed before conditions are finalized in order to see whether the constraints are set as intended, or whether there is any unintended motion (fig. 15). Also, the various constraints that are set are displayed hierarchized by type in the Model Manager (fig. 16). Constraint conditions that are needed as design variables can be located easily.

Fig. 14 Improved robustness for constraint functions
Fig. 14 Improved robustness for constraint functions

Fig. 15 Preview display during constraint setting
Fig. 15 Preview display during constraint setting

Fig. 16 Constraint condition hierarchy (left)(right shows the constraint conditions list from the previous version)
Fig. 16 Constraint condition hierarchy (left)
(right shows the constraint conditions list from the previous version)

Improved Geometry Editor

Several points of improvement in the Geometry Editor's operability when creating model geometries are presented here.
A highly-requested feature for confirming measurements in the Geometry Editor is now available. The need to go back and fix mistakes is reduced because measurements can be checked at each point while creating a geometry without changing to the main Designer screen. Functions for checking interference between regions and solids have also been added. These also reduce the need to go back to fix mistakes, by checking whether there is interference during model creation.
Geometry editing functions have also been strengthened. Direct editing of assemblies constructed from multiple parts is possible. Up to now operations were necessary for each part when setting features for geometry models, but in Ver.12.1, features can be set to assemblies directly. Fig. 18 shows an example of direct application of an extrude cut to an assembly to change it to a 1/2 model, using a full model of an electromagnetic relay.
Further, it is possible to select either basic shapes, constraints, or regions for editing operations by applying a select filter function to operation targets (fig. 19). For example, if you only want to reapply constraints and you click to select the constraint filter, the operation target will always be constraint only, and basic shape or region will not be not erroneously selected. This means that not only is selection easy, but also mistakes due to operation can be avoided with this function.

Fig. 17 Confirming measurements (left), and checking region interference (right) with the Geometry Editor
Fig. 17 Confirming measurements (left), and checking region interference (right) with the Geometry Editor

Fig. 18 Extrude cut on an assembly
Fig. 18 Extrude cut on an assembly

Fig. 19 Selecting a setting target using select filter (constraint selection (left), region selection (right))
Fig. 19 Selecting a setting target using select filter (constraint selection (left), region selection (right))

In Conclusion

The functions of Ver.12.1 introduced in this issue are also published in the New Features materials found at the webpage below, so please take a look.
JMAG-Designer Ver.12.1 New Feature (SWF, 3,701KB)

If there are any points on which you are unclear regarding the new functions, or if you would like more information, please feel free to contact our support staff.

(Takayuki Nishio)

Contents

  1. Implementing JMAG - Mazda Motor Corporation, Using Simulation to Support Automobile Evolution -
  2. Product Report - Introducing JMAG-Designer Ver.12.1 -
  3. Explaining FEA - Issue 3 FEA for Understanding Detailed Phenomena -
  4. Paper Introduction - Issue 4 Applications for Induction Heating Phenomena -
  5. Fully Mastering JMAG - Common Questions for JMAG -
  6. Fully Mastering JMAG - Issue 9 Understanding Thermal from A to Z -
  7. Event Information


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