JMAG Newsletter January, 2014Product Report

[Back]

Introducing JMAG-Designer Ver.13

We released JMAG-Designer Ver.13.0 in December, 2013. We have released Version 13.0 (which we'll call Ver. 13 from here on). With Ver.13, we focused on functional development aimed at high speed calculation and detailed modeling, in particular. The solver features the first parallel solver made for commercial use in the electromagnetic field analysis segment. Modeling technologies include higher accuracy in loss calculation for starters, realize small multiphysics through coupling of thermal and structural analyses for electromagnetic field analyses and provided a wide array of new functions. This product report introduces the most important new functions in Ver.13.

Overview

We released JMAG-Designer Ver.13 in January, 2013. Newly added are 40 or more functions in the development of Ver.13 including high parallel solver, high precision loss modeling, multiphysics function (Small Multiphysics as its main functions (Fig. 1).
The high parallel solver newly included in Ver. 13 drastically improves the actual time needed and degree of detail in an electromagnetic field analysis. This powerful solver enables users to avoid having to worry over how much time they'll need for analysis and enables trying out a wide variety of ideas.
With material modeling, Ver. 13 has been equipped with a material properties database that has a hysteresis group. Iron loss calculations can tap into this built-in data for analyses and, by allowing for minor loops in the details, improve the degree of accuracy in iron loss. Moreover, a higher precision loss analysis is realized taking into consideration the effect of stress due to production degradation. Analysis makes high-fidelity material modeling a reality not by envisioning a convenient ideal, but by being as close to an actual state as possible.
For phenomena modeling, we have strengthened coupling functions within JMAG to enable any user to use the software from anywhere at all as part of our pursuit of multiphysics. We will present analysis functions (small multiphysics) in the form of running magnetic field analysis including centrifugal force or thermal-magnetic field coupled analyses allowing for the effect of using a 1D heat analysis and a new coupling framework developed in our pursuit to become easier to use.

Fig. 1 Three Concepts and Functions Characterizing Ver. 13
Fig. 1 Three Concepts and Functions Characterizing Ver. 13

High speed solver

One of the most important features of Ver. 13 is the accelerated solver. A new acceleration technique in Ver. 13 is Multi-Slice function for achieving high speed analysis by using high parallel solver and skew effect for large/detailed analysis for 2D motor models.


High Parallel Solver (Magnetic Field Analysis)

The new high parallel solver now supports 128 parallels compared to the just 8 parallels maximum supported in a conventional SMP/DMP. This shows a comparison on an IPM motor model between the high parallel solver and the conventional SMP solver (Fig. 2). This shows solving speed is greatly enhanced without any decline in accuracy.
The high parallel solver drastically reduces analysis time and also achieves a large model analysis at high precision, which has been considered until now to be unrealistic. Analysis themes we could not venture into before are now possible, such as laminated steel sheets, coil wire/ends and detailed eddy current loss analysis for large machines.
For example, a transformer is composed of a number of parts including tank, clamp, shield and cover plate surrounding the body. Since each part becomes the generation source of eddy loss, detailed modeling requires an evaluation of local overheating. Until now, analysis scale was an obstacle, but making the analysis scale smaller also ensures the geometry must be simplified, which meant that loss evaluation had to be something qualitative.
The high parallel solver enables modeling of only the necessary degree of detail. Confirm concentrations of leakage flux caused by the connector or shield through the clamp acting as a magnetic bypass to the tank or eddy current causing localized heat. The high parallel solver will not only realize highly detailed analyses, it will also be able to show through the analysis detailed physical phenomena that had not been capable of being confirmed before.

 Fig. 2 Example of Acceleration using High Parallel Solver
Fig. 2 Example of Acceleration using High Parallel Solver

HPC


Multi-Slicing

For skewed motors, a 3D analysis may be often necessary considering magnetic flux in the axis direction. The scale of the analysis can be massive in the 3D analysis, and calculation cost is much more expensive than 2D analysis when it comes to calculation of analysis time and disk capacity to save data.
The Multi-Slice function is a new analysis function taking into consideration skew with a 2D model. The skew effect is allowed for by specifying the skew angle and cross-section of the axial direction. This function performs analysis allowing for skew by virtually using multiple models with different relative positions of rotor and stator from a 2D model. As this is an analysis bade on a 2D analysis, the answer is obtained quicker than it would be under a 3D analysis (Fig. 3, Table 1).

Fig. 3 Image of Analysis under Multi-Slicing
Fig. 3 Image of Analysis under Multi-Slicing

Table 1 Comparison of Multi-Slice Method and #D Analysis Calculation Time
Table 1 Comparison of Multi-Slice Method and #D Analysis Calculation Time

Multi-Slice Method

High-Speed, High-Precision Loss Calculation

JMAG has engaged in an effort to support higher accuracy of loss calculation for magnetic devices such as motors, depending on the various loss factors such as hysteresis priorities, laminated structure modeling and production degradation.
In Ver.13, we have continued with this flow and raised our standard of detail to an even higher level.


Greater Precision of Stress-Dependent Iron Loss Calculations

When evaluating the iron loss value, an analysis considering the impact of stress caused by processing deformation generated in the manufacturing process may be necessary. JMAG has focused on iron loss calculation functions (evaluation of stress scalar values) as a symbol of stress, but research in recent years has taught us of the importance of change over time in magnetic flux focused on the compressed primary axis direction of the stress.
The newly added stress dependency iron loss calculation function (tensor-vector value evaluation) enables a loss analysis allowing for magnetic flux density changes over time in response to the stress of each primary axis (Fig. 4, 5). In comparison to the conventional analyses, the ability to consider the impact of difference in directions of principal stress and magnetic flux density greatly enhanced the detail of iron loss analyses.

Fig. 4 Difference in Directions between Principal Stress Distribution (left) and Magnetic Flux Density Distribution (right)
Fig. 4 Difference in Directions between Principal Stress Distribution (left) and Magnetic Flux Density Distribution (right)

Fig. 5 Comparison of Differences in Handling Stress (Left: Scalar, Right: Tensile)
Fig. 5 Comparison of Differences in Handling Stress (Left: Scalar, Right: Tensile)

Iron Loss Calculation of Stress Dependency


Adding the Hysteresis Properties of a Magnetic Steel Sheet

Hysteresis properties affect not only the iron loss in magnetic devices, but also response characteristics, so there is a strong requirement for allowance to be made of this in analyses. JMAG enables analyses of detailed magnetic properties that take into account the hysteresis properties. However, since data of hysteresis properties usable in analyses is almost never found in market, obtaining it requires significant time and cost for many users.
With support from joint research facilities such as the Electrical Machinery & Apparatus Laboratory at Doshisha University, JMAG incorporated into the JMAG material database commonly used hysteresis property data of magnetic steel sheets (various types of 35A- and 50A-class magnetic steel sheets) (Fig.6). Users wishing to use the above mentioned magnetic steel sheets can realize a high-precision loss analysis without wasting time preparing material data.

Fig. 6 Example of Hysteresis Measurement Results to be Included
Fig. 6 Example of Hysteresis Measurement Results to be Included

Material Database

Multiphysics

Complex physical phenomena in reality need to be tackled from multifaceted approaches including magnetic, thermal and structural aspects in product design. However, when these designs are performed by each division in most cases, a need to fulfill the demand for the trade-off for each request item may cause a lot of hassle when trying to obtain optimal design values. To solve this problem, a cooperated/coupled analysis simulation via CAE dealing with complex phenomena would be an effective measure, but users also tend to hesitate to use this due to prioritizing preliminary learning of each analysis step.
The Multiphysics function newly introduced for Ver. 13 allows even magnetic circuit designers to easily handle an analysis taking into consideration the impact of both centrifugal force and heat (small multiphysics).
We have also added a new level on the JMAG-Designer treeview for coupling analysis functions, presenting a comprehensive coupling analysis environment that's easy to use.
Vibration analyses can now also handle items such as vibration phenomena due to having added an analysis function to the time region.

Multiphysics


Small Multiphysics

With the concept of multiphysics analysis functions that anybody can use easily, there is a small multiphysics function that enables coupling analyses accounting for centrifugal force analysis or heat during drive time in a magnetic field analysis.

1. Magnetic Field Analysis/Centrifugal Force Calculation
Centrifugal force can be calculated when concurrently running a magnetic field analysis for motors (Figure 7). Electric/magnetic circuit design such as torque and induced voltage under the specified rotational speed can be examined besides strength design to check if it has sufficient robustness to withstand the centrifugal force. Furthermore, the function to render and check physical quantity concurrently based on different phenomena such as stress/displacement distribution and magnetic flux distribution helps us to understand the phenomena in an objective manner.

Fig. 7 Mises Stress Distribution of IPM Motor Rotor
Fig. 7 Mises Stress Distribution of IPM Motor Rotor


2. Magnetic Field Analysis/ Thermal Equivalent Circuit Calculation
What is vital in a thermal analysis is heat exchange and heat release phenomena through parts which are not modeled in the magnetic field analysis, such as the bobbin and case. Detailed modeling which is often required in the magnetic field - thermal coupled analysis was an encouraging factor for users to perform an analysis.
In the newly created magnetic field-thermal coupled analysis using the heat equivalent circuit, settings in the heat equivalent circuit from the circuit editing screen for the magnetic field analysis enables an analysis taking into account the heat generation phenomena due to copper and iron losses. This shows, without using a complicated 3D thermal model and by employing a heat equivalent circuit, how increasing the coil heat generation and resistance values lowers the torque (Fig. 8). This analysis can be specified and run from a magnetic field analysis, allowing even non-experts such as electric/magnetic circuit designers to easily handle an analysis taking into consideration the heat generation.

Fig. 8 Easy Evaluation of the Heat Generation Effect using Heat Equivalent Circuit
Fig. 8 Easy Evaluation of the Heat Generation Effect using Heat Equivalent Circuit

Small Multiphysics


Thermal Stress Analysis Study

Heat generation phenomenon due to factors such as eddy current brings structural deformation of objects due to thermal stress, as well as has an impact on the physical property value such as electrical conductivity.
With the thermal stress analysis study, if the coefficient of thermal expansion in material properties is defined, it's possible for the temperature distribution as a load creating heat that outputs stress distribution and displacement distribution (Fig. 9). For conductors like bus bars that are subject to heat deformation in large currents, we provide an effective evaluation method.

Fig 9 Temperature Distribution and Thermal Deformation caused by Eddy Current Loss as a Heat Source図8 渦電流損失ヲ熱源トシタ熱変形
Fig 9 Temperature Distribution and Thermal Deformation caused by Eddy Current Loss as a Heat Source


New Framework for Coupled Analyses

1. Direct Execution of Coupled Analysis
A coupled analysis combines multiple analysis types such as magnetic field analysis and thermal analysis, but conventional JMAG-Designer did not support a framework for the coupled analysis and from Ver. 13 there is a new framework for coupling analysis. Preparing a new hierarchy called the analysis group in the new framework, magnetic field analysis studies and thermal analysis studies which are necessary for a coupled analysis are collectively managed within a group. This framework also supported parametric analyses during coupled analyses, greatly enhancing operability during coupled analysis.

Fig. 10 Adding Analysis Group
Fig. 10 Adding Analysis Group


2. Geometry data sharing between different analysis types
Target parts to be analyzed in the coupled analysis differ depending on the magnetic field analysis, thermal analysis and structural analysis. For example, in the high frequency induction heating, although heating coils are modeled for the magnetic field analysis to handle work piece's heat generation phenomena, only work piece is handled without modeling the heating coils for thermal analysis. Nonmagnetic objects which are omitted in the magnetic field analysis will be included as targets in the structural analysis.
As requirements differ regarding part data for coupled analyses or analysis types like this, each study is divided up into its own different solid model.
Ver.13 provides the shared solid model under new coupled analysis framework, which was divided by each analysis type in earlier versions (Fig. 11). Depending on the analysis type, parts not needed for an analysis can be directly controlled from the JMAG-Designer main window. For this reason, as a CAD model is a convenient function as it enables selection of the necessary parts for each particular type of analysis, so preparing a single, detailed, solid model in advance it will ensure there is enough for the geometry.

Fig. 11 Data Sharing in the Magnetic Field-Thermal Coupled Analysis (Gear Quenching)
Fig. 11 Data Sharing in the Magnetic Field-Thermal Coupled Analysis (Gear Quenching)


Vibration Transient Analysis

A transient response analysis function is added to the Ver. 13 vibration analysis, a structural analysis module (DS).
However, there are many cases requiring response sensitivity to a more instantaneous vibratory force of the type that can only damage equipment instead of a steady vibration phenomena. Even for users who deal with the electric/mechanical system, there is an increasing demand for acquiring a real time response of stress and displacement to the transient changes based on the electromagnetic phenomena.
This newly added new transient response analysis function enabled users to grasp stress and displacement variation overtime depending on the electromagnetic force generated instantly (Fig. 12).

Fig. 12 Variations in Suction Core Vibration Speed due to Moving Electromagnet
Fig. 12 Variations in Suction Core Vibration Speed due to Moving Electromagnet

Vibration Transient Analysis

Generating Mesh

Stray loss generated in large transformers or generators is often addressed as the theme of analysis because of its size. Stray loss is often caused by loss in the thin sheet structure surrounding the body and analyses must take into account the skin effect when a mesh is generated. The thin mesh function is a new mesh generation technique to meet this requirement.


Thin Shell Mesh Generation

This function is a mesh generation function that has been vastly improved to make it applicable to complicated thin sheet structures through such means as crossing it with existing thin sheet mesh functions (Fig. 13). Generating a layered mesh in the direction of sheet thickness enhances the precision of mesh generation, highly accurate expression of eddy current and analysis convergence.

Fig. 13 Stray Loss Density Distribution in a Large Transformer
Fig. 13 Stray Loss Density Distribution in a Large Transformer
Fig. 13 Stray Loss Density Distribution in a Large Transformer

Mesh Modeling

JMAG-RT/Efficiency Map

The correction function for each amplitude or phase of current is added to meet the rising demand for JMAG-RT solutions required for generating a plant model of the high precision motor.
Furthermore, JMAG-RT Viewer newly added the efficiency map function for induction machines which was also in high demand, where the temperature dependency of the efficiency map can be taken into account.


Correction of rtt file current amplitude/phase difference

JMAG-RT is a tool capable of providing a highly accurate motor plant model, but it is possible to partially correct at times, depending on things such as its drive condition (say, using a 2D model to study the effect of inductance on magnetic saturation in the coil end or when examining the 3D effects).
The new JMAG-RT can incorporate corrective-use data sheets (csv files) in response to rtt files containing torque and magnetic flux output values arbitrarily for each current amplitude and phase (Fig. 14).

Fig. 14 Current Amplitude/Phase Correction Dialog Box
Fig. 14 Current Amplitude/Phase Correction Dialog Box

JMAG-RT


Efficiency Map Supporting Induction Machines and Consideration of Temperature Dependency

JMAG-RT is second most heavily used application for induction machines which are used as a target of variable speed control, except for PM motors.
Rendering efficiency maps using rtt files from induction motors to align with this, we have responded to the expression of many requirements and new efficiency map functions will support induction motors (Fig. 15). Efficiency maps for induction machinery not only plot contours for each operation point, they also display slide contour mapping enabling optimal efficiency.
Also considering temperature correction coefficient when an efficiency map is generated enables confirmation of the temperature dependency of the efficiency map.

Fig. 15 Induction Motor Efficiency Map Example
Fig. 15 Induction Motor Efficiency Map Example
Fig. 16 Efficiency Map Temperature Dependency
20 deg C Efficiency Map
矢印 Fig. 16 Efficiency Map Temperature Dependency
60 deg C Efficiency Map
Fig. 16 Efficiency Map Temperature Dependency

JMAG-RT Viewer

Optimization


Displaying sensitivity analysis results using response surface

We've made the optimization function display a response value on the response surface for a design variable. Since the response values are displayed using contour for multiple variables, it is possible to confirm the sensitivity to design variables which is in the relationship of trade-off (Fig. 17).
Changing and improving the optimization algorithm enabled significant improvements in the optimum value. (*)
(*) We recommend setting one target function in Ver. 13's optimization function.

Fig. 17 Response Surface Results for Current Phase/Magnetic Width, Torque
Fig. 17 Response Surface Results for Current Phase/Magnetic Width, Torque

Optimization

Results Analysis

Ver.13 newly added a new function controlling display of distribution weights to enable clearer views of results.


Controlling Result Rendering Type for Each Part

To confirm the analysis results using contour or vector, they were exported to all of the targets displayed in the earlier versions, but displaying the contours and vectors at the same time will render them overlapping and make them difficult to view.
The new results rendering function can specify contours and vectors for each part, depending on the requirements. Fig. 18 shows what happens when flux leakage generated from the coil and core becomes loss in the shield. By showing loss generation only in the shield it becomes easy to discern the cause and effect of the leakage flux and loss it generates.

Fig. 18 Magnetic Flux Density (Vector) and Joule Loss (Contour) (Single Phase Transformer 1/8 model used)
Fig. 18 Magnetic Flux Density (Vector) and Joule Loss (Contour) (Single Phase Transformer 1/8 model used)


Density Control of Vector Rendering

Vector output being rendered in the unit of element depends on the mesh density. Models comprised of detailed mesh have many vectors to display, which makes it difficult to see some of the detailed distribution.
Using the in-built vector rendering density control function has enabled display of vector distribution, which makes it easier for users to see.

Fig. 19 Density Control of Magnetic Flux Density Vector (Magnetic Head Model)
Fig. 19 Density Control of Magnetic Flux Density Vector (Magnetic Head Model)

Results Evaluation

Model-based Development

We have tried with JMAG to realize an interface environment that seamlessly blends structural/vibration analyses and thermal liquid analyses with JMAG magnetic field analyses to make a reality of CAE creating a model-based development environment.
Ver. 13 expands to handle types of electromagnetic force from the Multi-Purpose Export Tool or LMS Virtual Lab interface.


Expansion of the Multi-Purpose File Export Tool

The multi-purpose export tool is a tool with the objective of taking JMAG analysis results such as electromagnetic force or loss and using them as load conditions for structural analysis or thermal analysis software other than JMAG.
File output in the Universal format is available as well as in the Nastran format. Broaden the CAE software band using JMAG's results.

Multi-Purpose File Export Tool


LMS-Virtual.Lab Interface expansion

LMS Virtual Lab. is a CAE software with an established reputation in the field of sound/vibration analysis. JMAG draws on electromagnetic force results obtained until now to enable mapping of electromagnetic force distribution generated on magnetic surfaces and transfer these to LMS Virtual.Lab.
The new LMS Virtual.Lab interface is also capable of adding to this a map of the internal distribution of electromagnetic force. Furthermore, Lorentz force and magnetostrictive force can also be mapped and vibration phenomena frequently occurring within electromagnetic phenomena can also be handled widely. Showing an example of using JMAG and LMS Virtual.Lab to obtain the sound pressure distribution emanated from magnetostrictive vibration generated from the core of the power transformer (Fig. 20).

Magnetic flux density distribution
Magnetic flux density distribution
Equivalent magnetostriction force vector
Equivalent magnetostriction force vector
Sound pressure distribution
Sound pressure distribution
Fig. 20 Example of Transformer Magnetostriction Vibration

LMS Virtual.Lab

In closing

The new functions described in this article have also been added to our Website and in seminars for updated versions of software.

(Takayuki Nishio)

Contents

 1. Implementing JMAG   - Panasonic Corporation   Taking household appliance technologies and presenting them to industry partners -
 2. Product Report   - Introducing JMAG-Designer Ver.13 -
 3. Product Report   - JMAG-VTB is Now Easier to Use -
 4. Solutions   - Motor Design Course   - Issue 2 Moving Forward with Motor Concept Design -
 5. Solutions   - Starting With Vibration Noise Analyses Vol. 1 (Motor Edition 1) -
 6. Paper Introduction   - Issue 6 Lesson on Advanced Iron Loss Analysis -
 7. Fully Mastering JMAG   - Common Questions for JMAG -
 8. Fully Mastering JMAG   - Issue 11 Electric Field Analysis from A to Z -
 9. JMAG University Partner Introduction   - Shanghai University -
 10. JMAG Product Partner Introduction   - Dassault Systèmes Simulia -
 11. Event Information


Top of Page

Contact US

Free Trial

Latest Issue
NewsLetter
January, 2016
Back Issue
Back Issue