The influence of demagnetisation and temperature on the performance of PM machines
Identifieur interne : 000684 ( Istex/Corpus ); précédent : 000683; suivant : 000685The influence of demagnetisation and temperature on the performance of PM machines
Auteurs : John Simkin ; Alex Michaelides ; Chris RileySource :
- COMPEL - The international journal for computation and mathematics in electrical and electronic engineering [ 0332-1649 ] ; 2006-07-01.
Abstract
Purpose The paper seeks to present finite element methods for modelling hard magnetic material magnetisation and degradation in service. It aims to describe methods of representing the hysteretic behaviour of permanent magnets, and allowing for variations in the material characteristics caused by temperature and demagnetising fields. Designmethodologyapproach A permanent magnet DC motor example is used to demonstrate the complete modelling cycle. The magnetisation of the ringsegments of the stator magnets was modelled using a transient, nonlinear, eddycurrent solver. The rings were transferred to the PMDC motor. The demagnetisation of the magnets in service was studied as a function of load, operating armature current and temperature. Findings The effect of hard magnetic material demagnetization was accurately quantified. Its dependence on the reversefield armature currents and operating temperature was demonstrated. The benefits of accurately representing the material characteristics in PMDC motors were clearly identified. Research limitationsimplications The model for hard magnetic materials under magnetizing and demagnetising fields can only be perfected by using measured data. The measurements are hard to perform, in particular the effect of demagnetising fields at an angle to the easy magnetization axis is very difficult to measure. Originalityvalue The paper enhances the understanding of the process of hard magnetic material magnetisation and demagnetisation, fully examining the mechanisms and their dependence on parameters such as magnetising and demagnetising fields and temperature. The paper demonstrates how FEA methods can help to design electrical machine by accurately representing magnetic material properties and processes.
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DOI: 10.1108/03321640610666925
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<record><TEI wicri:istexFullTextTei="biblStruct"><teiHeader><fileDesc><titleStmt><title xml:lang="en">The influence of demagnetisation and temperature on the performance of PM machines</title><author><name sortKey="Simkin, John" sort="Simkin, John" uniqKey="Simkin J" first="John" last="Simkin">John Simkin</name><affiliation><mods:affiliation>Vector Fields Ltd, Kidlington, UK</mods:affiliation></affiliation></author><author><name sortKey="Michaelides, Alex" sort="Michaelides, Alex" uniqKey="Michaelides A" first="Alex" last="Michaelides">Alex Michaelides</name><affiliation><mods:affiliation>Vector Fields Ltd, Kidlington, UK</mods:affiliation></affiliation></author><author><name sortKey="Riley, Chris" sort="Riley, Chris" uniqKey="Riley C" first="Chris" last="Riley">Chris Riley</name><affiliation><mods:affiliation>Vector Fields Ltd, Kidlington, UK</mods:affiliation></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">ISTEX</idno><idno type="RBID">ISTEX:BC93B02F4C3D64AE34315959746EEA6BEC9ADCE1</idno><date when="2006" year="2006">2006</date><idno type="doi">10.1108/03321640610666925</idno><idno type="url">https://api.istex.fr/document/BC93B02F4C3D64AE34315959746EEA6BEC9ADCE1/fulltext/pdf</idno><idno type="wicri:Area/Istex/Corpus">000684</idno></publicationStmt><sourceDesc><biblStruct><analytic><title level="a" type="main" xml:lang="en">The influence of demagnetisation and temperature on the performance of PM machines</title><author><name sortKey="Simkin, John" sort="Simkin, John" uniqKey="Simkin J" first="John" last="Simkin">John Simkin</name><affiliation><mods:affiliation>Vector Fields Ltd, Kidlington, UK</mods:affiliation></affiliation></author><author><name sortKey="Michaelides, Alex" sort="Michaelides, Alex" uniqKey="Michaelides A" first="Alex" last="Michaelides">Alex Michaelides</name><affiliation><mods:affiliation>Vector Fields Ltd, Kidlington, UK</mods:affiliation></affiliation></author><author><name sortKey="Riley, Chris" sort="Riley, Chris" uniqKey="Riley C" first="Chris" last="Riley">Chris Riley</name><affiliation><mods:affiliation>Vector Fields Ltd, Kidlington, UK</mods:affiliation></affiliation></author></analytic><monogr></monogr><series><title level="j">COMPEL - The international journal for computation and mathematics in electrical and electronic engineering</title><idno type="ISSN">0332-1649</idno><imprint><publisher>Emerald Group Publishing Limited</publisher><date type="published" when="2006-07-01">2006-07-01</date><biblScope unit="volume">25</biblScope><biblScope unit="issue">3</biblScope><biblScope unit="page" from="741">741</biblScope><biblScope unit="page" to="747">747</biblScope></imprint><idno type="ISSN">0332-1649</idno></series><idno type="istex">BC93B02F4C3D64AE34315959746EEA6BEC9ADCE1</idno><idno type="DOI">10.1108/03321640610666925</idno><idno type="filenameID">1740250324</idno><idno type="original-pdf">1740250324.pdf</idno><idno type="href">03321640610666925.pdf</idno></biblStruct></sourceDesc><seriesStmt><idno type="ISSN">0332-1649</idno></seriesStmt></fileDesc><profileDesc><textClass></textClass><langUsage><language ident="en">en</language></langUsage></profileDesc></teiHeader><front><div type="abstract">Purpose The paper seeks to present finite element methods for modelling hard magnetic material magnetisation and degradation in service. It aims to describe methods of representing the hysteretic behaviour of permanent magnets, and allowing for variations in the material characteristics caused by temperature and demagnetising fields. Designmethodologyapproach A permanent magnet DC motor example is used to demonstrate the complete modelling cycle. The magnetisation of the ringsegments of the stator magnets was modelled using a transient, nonlinear, eddycurrent solver. The rings were transferred to the PMDC motor. The demagnetisation of the magnets in service was studied as a function of load, operating armature current and temperature. Findings The effect of hard magnetic material demagnetization was accurately quantified. Its dependence on the reversefield armature currents and operating temperature was demonstrated. The benefits of accurately representing the material characteristics in PMDC motors were clearly identified. Research limitationsimplications The model for hard magnetic materials under magnetizing and demagnetising fields can only be perfected by using measured data. The measurements are hard to perform, in particular the effect of demagnetising fields at an angle to the easy magnetization axis is very difficult to measure. Originalityvalue The paper enhances the understanding of the process of hard magnetic material magnetisation and demagnetisation, fully examining the mechanisms and their dependence on parameters such as magnetising and demagnetising fields and temperature. The paper demonstrates how FEA methods can help to design electrical machine by accurately representing magnetic material properties and processes.</div></front></TEI><istex><corpusName>emerald</corpusName><author><json:item><name>John Simkin</name><affiliations><json:string>Vector Fields Ltd, Kidlington, UK</json:string></affiliations></json:item><json:item><name>Alex Michaelides</name><affiliations><json:string>Vector Fields Ltd, Kidlington, UK</json:string></affiliations></json:item><json:item><name>Chris Riley</name><affiliations><json:string>Vector Fields Ltd, Kidlington, UK</json:string></affiliations></json:item></author><subject><json:item><lang><json:string>eng</json:string></lang><value>Magnetism</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>Finite element analysis</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>Electric motors</value></json:item></subject><language><json:string>eng</json:string></language><abstract>Purpose The paper seeks to present finite element methods for modelling hard magnetic material magnetisation and degradation in service. It aims to describe methods of representing the hysteretic behaviour of permanent magnets, and allowing for variations in the material characteristics caused by temperature and demagnetising fields. Designmethodologyapproach A permanent magnet DC motor example is used to demonstrate the complete modelling cycle. The magnetisation of the ringsegments of the stator magnets was modelled using a transient, nonlinear, eddycurrent solver. The rings were transferred to the PMDC motor. The demagnetisation of the magnets in service was studied as a function of load, operating armature current and temperature. Findings The effect of hard magnetic material demagnetization was accurately quantified. Its dependence on the reversefield armature currents and operating temperature was demonstrated. The benefits of accurately representing the material characteristics in PMDC motors were clearly identified. Research limitationsimplications The model for hard magnetic materials under magnetizing and demagnetising fields can only be perfected by using measured data. The measurements are hard to perform, in particular the effect of demagnetising fields at an angle to the easy magnetization axis is very difficult to measure. Originalityvalue The paper enhances the understanding of the process of hard magnetic material magnetisation and demagnetisation, fully examining the mechanisms and their dependence on parameters such as magnetising and demagnetising fields and temperature. The paper demonstrates how FEA methods can help to design electrical machine by accurately representing magnetic material properties and processes.</abstract><qualityIndicators><score>4.069</score><pdfVersion>1.3</pdfVersion><pdfPageSize>519 x 680 pts</pdfPageSize><refBibsNative>true</refBibsNative><keywordCount>3</keywordCount><abstractCharCount>1765</abstractCharCount><pdfWordCount>1165</pdfWordCount><pdfCharCount>8177</pdfCharCount><pdfPageCount>7</pdfPageCount><abstractWordCount>242</abstractWordCount></qualityIndicators><title>The influence of demagnetisation and temperature on the performance of PM machines</title><genre><json:string>research-article</json:string></genre><host><volume>25</volume><pages><last>747</last><first>741</first></pages><issn><json:string>0332-1649</json:string></issn><issue>3</issue><subject><json:item><value>Engineering</value></json:item><json:item><value>Electrical & electronic engineering</value></json:item></subject><genre><json:string>journal</json:string></genre><language><json:string>unknown</json:string></language><title>COMPEL - The international journal for computation and mathematics in electrical and electronic engineering</title><doi><json:string>10.1108/compel</json:string></doi></host><publicationDate>2006</publicationDate><copyrightDate>2006</copyrightDate><doi><json:string>10.1108/03321640610666925</json:string></doi><id>BC93B02F4C3D64AE34315959746EEA6BEC9ADCE1</id><fulltext><json:item><original>true</original><mimetype>application/pdf</mimetype><extension>pdf</extension><uri>https://api.istex.fr/document/BC93B02F4C3D64AE34315959746EEA6BEC9ADCE1/fulltext/pdf</uri></json:item><json:item><original>false</original><mimetype>application/zip</mimetype><extension>zip</extension><uri>https://api.istex.fr/document/BC93B02F4C3D64AE34315959746EEA6BEC9ADCE1/fulltext/zip</uri></json:item><istex:fulltextTEI uri="https://api.istex.fr/document/BC93B02F4C3D64AE34315959746EEA6BEC9ADCE1/fulltext/tei"><teiHeader><fileDesc><titleStmt><title level="a" type="main" xml:lang="en">The influence of demagnetisation and temperature on the performance of PM machines</title></titleStmt><publicationStmt><authority>ISTEX</authority><publisher>Emerald Group Publishing Limited</publisher><availability><p>EMERALD</p></availability><date>2006</date></publicationStmt><sourceDesc><biblStruct type="inbook"><analytic><title level="a" type="main" xml:lang="en">The influence of demagnetisation and temperature on the performance of PM machines</title><author><persName><forename type="first">John</forename><surname>Simkin</surname></persName><affiliation>Vector Fields Ltd, Kidlington, UK</affiliation></author><author><persName><forename type="first">Alex</forename><surname>Michaelides</surname></persName><affiliation>Vector Fields Ltd, Kidlington, UK</affiliation></author><author><persName><forename type="first">Chris</forename><surname>Riley</surname></persName><affiliation>Vector Fields Ltd, Kidlington, UK</affiliation></author></analytic><monogr><title level="j">COMPEL - The international journal for computation and mathematics in electrical and electronic engineering</title><idno type="pISSN">0332-1649</idno><idno type="DOI">10.1108/compel</idno><imprint><publisher>Emerald Group Publishing Limited</publisher><date type="published" when="2006-07-01"></date><biblScope unit="volume">25</biblScope><biblScope unit="issue">3</biblScope><biblScope unit="page" from="741">741</biblScope><biblScope unit="page" to="747">747</biblScope></imprint></monogr><idno type="istex">BC93B02F4C3D64AE34315959746EEA6BEC9ADCE1</idno><idno type="DOI">10.1108/03321640610666925</idno><idno type="filenameID">1740250324</idno><idno type="original-pdf">1740250324.pdf</idno><idno type="href">03321640610666925.pdf</idno></biblStruct></sourceDesc></fileDesc><profileDesc><creation><date>2006</date></creation><langUsage><language ident="en">en</language></langUsage><abstract><p>Purpose The paper seeks to present finite element methods for modelling hard magnetic material magnetisation and degradation in service. It aims to describe methods of representing the hysteretic behaviour of permanent magnets, and allowing for variations in the material characteristics caused by temperature and demagnetising fields. Designmethodologyapproach A permanent magnet DC motor example is used to demonstrate the complete modelling cycle. The magnetisation of the ringsegments of the stator magnets was modelled using a transient, nonlinear, eddycurrent solver. The rings were transferred to the PMDC motor. The demagnetisation of the magnets in service was studied as a function of load, operating armature current and temperature. Findings The effect of hard magnetic material demagnetization was accurately quantified. Its dependence on the reversefield armature currents and operating temperature was demonstrated. The benefits of accurately representing the material characteristics in PMDC motors were clearly identified. Research limitationsimplications The model for hard magnetic materials under magnetizing and demagnetising fields can only be perfected by using measured data. The measurements are hard to perform, in particular the effect of demagnetising fields at an angle to the easy magnetization axis is very difficult to measure. Originalityvalue The paper enhances the understanding of the process of hard magnetic material magnetisation and demagnetisation, fully examining the mechanisms and their dependence on parameters such as magnetising and demagnetising fields and temperature. The paper demonstrates how FEA methods can help to design electrical machine by accurately representing magnetic material properties and processes.</p></abstract><textClass><keywords scheme="keyword"><list><head>Keywords</head><item><term>Magnetism</term></item><item><term>Finite element analysis</term></item><item><term>Electric motors</term></item></list></keywords></textClass><textClass><keywords scheme="Emerald Subject Group"><list><label>cat-ENGG</label><item><term>Engineering</term></item><label>cat-EEE</label><item><term>Electrical & electronic engineering</term></item></list></keywords></textClass></profileDesc><revisionDesc><change when="2006-07-01">Published</change></revisionDesc></teiHeader></istex:fulltextTEI><json:item><original>false</original><mimetype>text/plain</mimetype><extension>txt</extension><uri>https://api.istex.fr/document/BC93B02F4C3D64AE34315959746EEA6BEC9ADCE1/fulltext/txt</uri></json:item></fulltext><metadata><istex:metadataXml wicri:clean="corpus emerald not found" wicri:toSee="no header"><istex:xmlDeclaration>version="1.0" encoding="UTF-8"</istex:xmlDeclaration><istex:document><!-- Auto generated NISO JATS XML created by Atypon out of MCB DTD source files. Do Not Edit! --><article dtd-version="1.0" xml:lang="en" article-type="research-article"><front><journal-meta><journal-id journal-id-type="publisher-id">compel</journal-id><journal-id journal-id-type="doi">10.1108/compel</journal-id><journal-title-group><journal-title>COMPEL - The international journal for computation and mathematics in electrical and electronic engineering</journal-title></journal-title-group><issn pub-type="ppub">0332-1649</issn><publisher><publisher-name>Emerald Group Publishing Limited</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.1108/03321640610666925</article-id><article-id pub-id-type="original-pdf">1740250324.pdf</article-id><article-id pub-id-type="filename">1740250324</article-id><article-categories><subj-group subj-group-type="type-of-publication"><compound-subject><compound-subject-part content-type="code">research-article</compound-subject-part><compound-subject-part content-type="label">Research paper</compound-subject-part></compound-subject></subj-group><subj-group subj-group-type="subject"><compound-subject><compound-subject-part content-type="code">cat-ENGG</compound-subject-part><compound-subject-part content-type="label">Engineering</compound-subject-part></compound-subject><subj-group><compound-subject><compound-subject-part content-type="code">cat-EEE</compound-subject-part><compound-subject-part content-type="label">Electrical & electronic engineering</compound-subject-part></compound-subject></subj-group></subj-group></article-categories><title-group><article-title>The influence of demagnetisation and temperature on the performance of PM machines</article-title></title-group><contrib-group><contrib contrib-type="author"><string-name><given-names>John</given-names> <surname>Simkin</surname></string-name><aff>Vector Fields Ltd, Kidlington, UK</aff></contrib><x></x><contrib contrib-type="author"><string-name><given-names>Alex</given-names> <surname>Michaelides</surname></string-name><aff>Vector Fields Ltd, Kidlington, UK</aff></contrib><x></x><contrib contrib-type="author"><string-name><given-names>Chris</given-names> <surname>Riley</surname></string-name><aff>Vector Fields Ltd, Kidlington, UK</aff></contrib></contrib-group><pub-date pub-type="ppub"><day>01</day><month>07</month><year>2006</year></pub-date><volume>25</volume><issue>3</issue><issue-title content-type="short">ISEF 2005 conference papers</issue-title><fpage>741</fpage><lpage>747</lpage><permissions><copyright-statement>© Emerald Group Publishing Limited</copyright-statement><copyright-year>2006</copyright-year><license license-type="publisher"><license-p></license-p></license></permissions><self-uri content-type="pdf" xlink:href="03321640610666925.pdf"></self-uri><abstract><sec><title content-type="abstract-heading">Purpose</title><x> – </x><p>The paper seeks to present finite element methods for modelling hard magnetic material magnetisation and degradation “in service”. It aims to describe methods of representing the hysteretic behaviour of permanent magnets, and allowing for variations in the material characteristics caused by temperature and demagnetising fields.</p></sec><sec><title content-type="abstract-heading">Design/methodology/approach</title><x> – </x><p>A permanent magnet DC motor example is used to demonstrate the complete modelling cycle. The magnetisation of the ring‐segments of the stator magnets was modelled using a transient, non‐linear, eddy‐current solver. The rings were transferred to the PMDC motor. The de‐magnetisation of the magnets “in service” was studied as a function of load, operating armature current and temperature.</p></sec><sec><title content-type="abstract-heading">Findings</title><x> – </x><p>The effect of hard magnetic material de‐magnetization was accurately quantified. Its dependence on the reverse‐field armature currents and operating temperature was demonstrated. The benefits of accurately representing the material characteristics in PMDC motors were clearly identified.</p></sec><sec><title content-type="abstract-heading">Research limitations/implications</title><x> – </x><p>The model for hard magnetic materials under magnetizing and demagnetising fields can only be perfected by using measured data. The measurements are hard to perform, in particular the effect of demagnetising fields at an angle to the easy magnetization axis is very difficult to measure.</p></sec><sec><title content-type="abstract-heading">Originality/value</title><x> – </x><p>The paper enhances the understanding of the process of hard magnetic material magnetisation and demagnetisation, fully examining the mechanisms and their dependence on parameters such as magnetising and demagnetising fields and temperature. The paper demonstrates how FEA methods can help to design electrical machine by accurately representing magnetic material properties and processes.</p></sec></abstract><kwd-group><kwd>Magnetism</kwd><x>, </x><kwd>Finite element analysis</kwd><x>, </x><kwd>Electric motors</kwd></kwd-group><custom-meta-group><custom-meta><meta-name>peer-reviewed</meta-name><meta-value>no</meta-value></custom-meta><custom-meta><meta-name>academic-content</meta-name><meta-value>yes</meta-value></custom-meta><custom-meta><meta-name>rightslink</meta-name><meta-value>included</meta-value></custom-meta></custom-meta-group></article-meta></front><body><sec><title>1 Introduction</title><p>High energy efficiency and power to weight ratio are paramount to the design of modern electrical machines in the ever‐demanding aerospace and automotive sectors. Designers strive to exploit new materials through improved design, and by tailoring the design to specific operating requirements and conditions. Therefore, highly functional and accurate machine simulation software is needed to achieve these tasks efficiently in an industrial environment. The software must be capable of representing the hysteretic behaviour of permanent magnets, and allow for variations in the material characteristics arising from changes in the operating temperature. This paper will describe recent software developments that address these requirements.</p></sec><sec><title>2 Modelling the magnetisation process in hard magnetic materials</title><p>A facility to model the magnetisation of permanent magnets has been included in the OPERA‐2d finite element analysis package <xref ref-type="bibr" rid="b1">Miller (2006)</xref> and <xref ref-type="bibr" rid="b2">Michaelides <italic>et al.</italic> (2002)</xref>. A transient, non‐linear, eddy‐current simulation of the magnetisation fixture can be performed in OPERA‐2d/DM. The model of the permanent magnet material is based on measured characteristics of the permanent magnet. During non‐linear analysis, OPERA‐2d/DM can use a virgin BH curve, shown in <xref ref-type="fig" rid="F_1740250324001">Figure 1</xref>, for material magnetisation and then secondary, temperature dependent “de‐magnetisation” BH curves as the field decreases.</p><p>The magnetisation distribution evaluated in OPERA‐2d/DM can be transferred to an OPERA‐2d “application model” for the static and dynamic electromagnetic analysis of the device in which the magnetised section(s) are employed.</p><p><xref ref-type="fig" rid="F_1740250324002">Figure 2</xref> shows the field distribution in a permanent magnet DC (PMDC) motor with ring‐segment magnets. The magnetisation of the ring‐segments was modelled using OPERA‐2d/DM and subsequently transferred for a magnetostatic analysis of the PMDC motor.</p><p><xref ref-type="fig" rid="F_1740250324003">Figure 3</xref> shows simulated and measured data of the radial field in the airgap of this PMDC machine. Good agreement between OPERA‐2d/DM/ST results and experiment is noted.</p></sec><sec><title>3 Modelling the de‐magnetisation of permanent magnet materials “in service”</title><p>The push for increased efficiency, smaller size, reliable performance and low cost solutions has forced the need for extending the demagnetisation model to account for demagnetisation of the magnetised segments “in service”.</p><p>The extended model starts as before with a virgin BH curve and sets of temperature dependent demagnetisation curves, as shown in <xref ref-type="fig" rid="F_1740250324004">Figure 4</xref>. Additional data defining the recoil behaviour of the material is now being provided and the necessary field history of the material is stored so that de‐magnetisation in the application device, the electrical machine, can be modelled.</p><p>A permanent magnet DC machine, employed in low cost automotive applications, was modelled with the wound rotor rotating to different positions, and the armature currents continuously changing according to the function of the commutator. The motor employed low‐cost ferrite permanent magnet rings, the magnetization of which was analysed in OPERA‐2d/DM, using the methods described in Section 2.</p><p><xref ref-type="fig" rid="F_1740250324005 F_1740250324006">Figures 5 and 6</xref> show the rotor at different positions, depicting the corresponding field distribution as well as armature currents.</p><p>During the simulation, the permanent magnet field is continuously monitored with the magnet operating on a de‐magnetisation or a recoil BH curve depending on the level of reverse field induced by the armature currents.</p><p>At the end of the pre‐defined rotation, the magnetisation level reached in different sections (elements) of the magnet, due to armature excitation effects, was recorded and compared with the levels prior to armature excitation (<xref ref-type="fig" rid="F_1740250324007">Figure 7</xref>). <xref ref-type="fig" rid="F_1740250324007">Figure 7</xref> confirms that armature reaction resulted in B‐field levels reaching a minimum of 0.15 T, a level which would result in the magnet operating on recoil curves as the armature excitation varied.</p><p>The “irreversible” effects of the armature reaction on the PM magnetisation at higher armature current levels can be quantified by plotting the B‐field just inside the permanent magnet after the end of the simulation (with armature currents reducing to zero) and comparing these with results before the onset of rotation (and with no armature excitation). Sections of the permanent magnet have been permanently demagnetised by approximately 5 per cent, as shown in <xref ref-type="fig" rid="F_1740250324008">Figure 8</xref>.</p></sec><sec><title>4 Three‐dimensional analysis</title><p>Magnetising fixtures may exhibit some important three‐dimensional effects, due to end windings. Three‐dimensional software is required to model these effects to enable the design of effective magnetisers.</p><p>The model of a magnetising fixture, used to magnetise hard magnetic PMDC motor rings is shown in <xref ref-type="fig" rid="F_1740250324009">Figure 9</xref>, and the resulting B‐field distribution in the magnetised rings is shown in <xref ref-type="fig" rid="F_1740250324010">Figure 10</xref>. The fixture end‐windings result in a higher B‐field level at the ends of the magnet ring.</p><p>Further work is currently concentrating on the extension of facilities for modelling the degradation of permanent magnets “in service”. Vector hysteresis loss models are also being considered to further enhance the accuracy of materials modelling, leading to the design of highly efficient electrical machines within the OPERA environment.</p></sec><sec><title>5 Conclusions</title><p>Novel modelling methods for the accurate modelling of the magnetisation of hard magnetic material sections were presented in this paper. The use of magnetised sections in the “application device” (a PMDC machine) was demonstrated. An extended demagnetisation model was subsequently presented, to model the degradation of the magnets “in service”. Three‐dimensional modelling of magnetising fixtures was also introduced.</p></sec><sec><fig position="float" id="F_1740250324001"><label><bold>Figure 1<x> </x></bold></label><caption><p>Virgin and secondary “de‐magnetisation” curves</p></caption><graphic xlink:href="1740250324001.tif"></graphic></fig></sec><sec><fig position="float" id="F_1740250324002"><label><bold>Figure 2<x> </x></bold></label><caption><p>Ring segment magnets, as part of a PMDC machine (model courtesy of Magnequench)</p></caption><graphic xlink:href="1740250324002.tif"></graphic></fig></sec><sec><fig position="float" id="F_1740250324003"><label><bold>Figure 3<x> </x></bold></label><caption><p>Radial B‐field in machine airgap</p></caption><graphic xlink:href="1740250324003.tif"></graphic></fig></sec><sec><fig position="float" id="F_1740250324004"><label><bold>Figure 4<x> </x></bold></label><caption><p>The extended de‐magnetisation model, including temperature dependent recoil curves</p></caption><graphic xlink:href="1740250324004.tif"></graphic></fig></sec><sec><fig position="float" id="F_1740250324005"><label><bold>Figure 5<x> </x></bold></label><caption><p>Equi‐potentials and armature currents in PMDC machine (9 degree position)</p></caption><graphic xlink:href="1740250324005.tif"></graphic></fig></sec><sec><fig position="float" id="F_1740250324006"><label><bold>Figure 6<x> </x></bold></label><caption><p>Equi‐potentials and armature currents in PMDC machine (27 degree position)</p></caption><graphic xlink:href="1740250324006.tif"></graphic></fig></sec><sec><fig position="float" id="F_1740250324007"><label><bold>Figure 7<x> </x></bold></label><caption><p>Minimum B‐levels reached in permanent magnet sections (elements)</p></caption><graphic xlink:href="1740250324007.tif"></graphic></fig></sec><sec><fig position="float" id="F_1740250324008"><label><bold>Figure 8<x> </x></bold></label><caption><p>B‐field before and after rotation (no armature excitation)</p></caption><graphic xlink:href="1740250324008.tif"></graphic></fig></sec><sec><fig position="float" id="F_1740250324009"><label><bold>Figure 9<x> </x></bold></label><caption><p>Three‐dimensional magnetiser model</p></caption><graphic xlink:href="1740250324009.tif"></graphic></fig></sec><sec><fig position="float" id="F_1740250324010"><label><bold>Figure 10<x> </x></bold></label><caption><p>B‐field in the resulting magnetised rings</p></caption><graphic xlink:href="1740250324010.tif"></graphic></fig></sec></body><back><ref-list><title>References</title><ref id="b2"><mixed-citation><person-group person-group-type="author"><string-name><surname>Michaelides</surname>, <given-names>A.</given-names></string-name></person-group>, <person-group person-group-type="author"><string-name><surname>Taylor</surname>, <given-names>S.C.</given-names></string-name></person-group> and <person-group person-group-type="author"><string-name><surname>Riley</surname>, <given-names>C.</given-names></string-name></person-group> (<year>2002</year>), <source><italic>Dynamic Analysis of Rotating and Linear Electrical Machines</italic></source>, Med'Power 2002,Athens.</mixed-citation></ref><ref id="b1"><mixed-citation><person-group person-group-type="author"><string-name><surname>Miller</surname>, <given-names>D.</given-names></string-name></person-group> (<year>2006</year>), “<article-title><italic>Simulation of the transient magnetization process in permanent magnet structures</italic></article-title>”, Internal Report, Magnequench Technology Center, Research Triangle Park, North Carolina.</mixed-citation></ref></ref-list><app-group><app id="APP1"><title>Corresponding author</title><p>John Simkin can be contacted at: John.Simkin@vectorfields.co.uk</p></app></app-group></back></article></istex:document></istex:metadataXml><mods version="3.6"><titleInfo lang="en"><title>The influence of demagnetisation and temperature on the performance of PM machines</title></titleInfo><titleInfo type="alternative" lang="en" contentType="CDATA"><title>The influence of demagnetisation and temperature on the performance of PM machines</title></titleInfo><name type="personal"><namePart type="given">John</namePart><namePart type="family">Simkin</namePart><affiliation>Vector Fields Ltd, Kidlington, UK</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Alex</namePart><namePart type="family">Michaelides</namePart><affiliation>Vector Fields Ltd, Kidlington, UK</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Chris</namePart><namePart type="family">Riley</namePart><affiliation>Vector Fields Ltd, Kidlington, UK</affiliation><role><roleTerm type="text">author</roleTerm></role></name><typeOfResource>text</typeOfResource><genre type="research-article" displayLabel="research-article"></genre><originInfo><publisher>Emerald Group Publishing Limited</publisher><dateIssued encoding="w3cdtf">2006-07-01</dateIssued><copyrightDate encoding="w3cdtf">2006</copyrightDate></originInfo><language><languageTerm type="code" authority="iso639-2b">eng</languageTerm><languageTerm type="code" authority="rfc3066">en</languageTerm></language><physicalDescription><internetMediaType>text/html</internetMediaType></physicalDescription><abstract>Purpose The paper seeks to present finite element methods for modelling hard magnetic material magnetisation and degradation in service. It aims to describe methods of representing the hysteretic behaviour of permanent magnets, and allowing for variations in the material characteristics caused by temperature and demagnetising fields. Designmethodologyapproach A permanent magnet DC motor example is used to demonstrate the complete modelling cycle. The magnetisation of the ringsegments of the stator magnets was modelled using a transient, nonlinear, eddycurrent solver. The rings were transferred to the PMDC motor. The demagnetisation of the magnets in service was studied as a function of load, operating armature current and temperature. Findings The effect of hard magnetic material demagnetization was accurately quantified. Its dependence on the reversefield armature currents and operating temperature was demonstrated. The benefits of accurately representing the material characteristics in PMDC motors were clearly identified. Research limitationsimplications The model for hard magnetic materials under magnetizing and demagnetising fields can only be perfected by using measured data. The measurements are hard to perform, in particular the effect of demagnetising fields at an angle to the easy magnetization axis is very difficult to measure. Originalityvalue The paper enhances the understanding of the process of hard magnetic material magnetisation and demagnetisation, fully examining the mechanisms and their dependence on parameters such as magnetising and demagnetising fields and temperature. The paper demonstrates how FEA methods can help to design electrical machine by accurately representing magnetic material properties and processes.</abstract><subject><genre>Keywords</genre><topic>Magnetism</topic><topic>Finite element analysis</topic><topic>Electric motors</topic></subject><relatedItem type="host"><titleInfo><title>COMPEL - The international journal for computation and mathematics in electrical and electronic engineering</title></titleInfo><genre type="Journal">journal</genre><subject><genre>Emerald Subject Group</genre><topic authority="SubjectCodesPrimary" authorityURI="cat-ENGG">Engineering</topic><topic authority="SubjectCodesSecondary" authorityURI="cat-EEE">Electrical & electronic engineering</topic></subject><identifier type="ISSN">0332-1649</identifier><identifier type="PublisherID">compel</identifier><identifier type="DOI">10.1108/compel</identifier><part><date>2006</date><detail type="title"><title>ISEF 2005 conference papers</title></detail><detail type="volume"><caption>vol.</caption><number>25</number></detail><detail type="issue"><caption>no.</caption><number>3</number></detail><extent unit="pages"><start>741</start><end>747</end></extent></part></relatedItem><identifier type="istex">BC93B02F4C3D64AE34315959746EEA6BEC9ADCE1</identifier><identifier type="DOI">10.1108/03321640610666925</identifier><identifier type="filenameID">1740250324</identifier><identifier type="original-pdf">1740250324.pdf</identifier><identifier type="href">03321640610666925.pdf</identifier><accessCondition type="use and reproduction" contentType="copyright">© Emerald Group Publishing Limited</accessCondition><recordInfo><recordContentSource>EMERALD</recordContentSource></recordInfo></mods></metadata><serie></serie></istex></record>Pour manipuler ce document sous Unix (Dilib)
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