Table Of ContentCOMPEL ISSN 0332-1649
The International Journal for Computation and Volume 21
Number 4
Mathematics in Electrical and Electronic
2002
Engineering
Selected papers from the 13th COMPUMAG Conference on the
Computation of Electromagnetic Fields Application Forum
Guest Editor
Professor F. Bouillault
This issue is
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Access to COMPEL online _________________________ 499
CONTENTS
Editorial advisory board ___________________________ 500
Abstracts and keywords ___________________________ 501
Introduction_______________________________________ 504
A current transformer modeling
YannLe Floch,Christophe Gue´rin,Dominique Boudaud, Ge´rard Meunier
andXavier Brunotte_____________________________________________ 505
Achieving the holy grail of seamless CAD data import
into analysis software
J. Oakley,C.P. Riley,S.Taylor andC.W. Trowbridge___________________ 512
Application of regularisation method of
quasi-singular integrals to compute eddy-current
distribution near cracks
PhilippeBeltrame andNoel Burais _________________________________ 519
Design of photonic band gap optical fibers using
finite elements
S.Guenneau,S.Lasquellec, A. Nicolet andF.Zolla____________________ 534
Analysis of techniques to compare complex data sets
CONTENTS
D.E.Coleby and A.P.Duffy _______________________________________ 540
continued
3-D eddy current computation for a transformer tank
HiroshiKanayama, Ryuji Shioya,Daisuke Tagami and
Satoshi Matsumoto______________________________________________ 554
Integration of control loops in coupled field circuit
model to study magnetic devices supplied by power
electronic converter and their control
G.Manot, Y. Lef`evre, H.Piquet andF.Richardeau____________________ 563
Calculation of winding losses using matrix modeling
of high frequency transformer
K.W.E. Cheng,K.F. Kwok,S.L.Ho andY.L.Ho______________________ 573
Eddy currents in thin plates modelled as surface
regions
Virgiliu Fireteanu,BernardPaya, JacquesNunsand TiberiuTudorache___ 581
Field and current flow analysis of the buried feeding
line of the innovative electric transport concept
STREAM
P.Alotto, F.Delfino, G.Molinari,M.Rossi, V.Sicilianoand
P.O. Ventura___________________________________________________ 591
Developments of an efficient global optimal design
technique – a combined approach of MLS and SA
algorithm
S.L.Ho, Shiyou Yang,Peihong Ni andH.C. Wong ____________________ 604
Magnetic field around the aluminium electrolysis
cells
AugustinMoraru, AureliuPanaitescu, IleanaPanaitescuand
Antoineta Soci__________________________________________________ 615
3D-FDTD characterization of an original low-loss
silicon line
AlexandreRichardson, Laurent Cirio,Laurent MartoglioandOdile Picon__ 624
A note from the publisher__________________________ 633
Index to volume 21, 2002 __________________________ 634
COMPEL EDITORIALADVISORYBOARD
21,4
ProfessorO.Biro ProfessorD.Lowther
GrazUniversityofTechnology,Graz,Austria McGillUniversity,VilleSaintLaurent,Quebec,
Canada
ProfessorJ.R.Cardoso
UniversityofSaoPaulo,SaoPaulo,Brazil ProfessorO.Mohammed
FloridaInternationalUniversity,Florida,USA
ProfessorC.Christopoulos
500
UniversityofNottingham,Nottingham,UK ProfessorG.Molinari
UniversityofGenoa,Genoa,Italy
ProfessorJ.-L.Coulomb
Laboratoired’ElectrotechniquedeGrenoble, ProfessorA.Razek
Grenoble,France EcoleSuperiordel’Electricite,GifsurYvette,
France
ProfessorX.Cui
NorthChinaElectricPowerUniversity,Baoding, ProfessorG.Rubinacci
Hebei,China UniversitadiCassino,Cassino,Italy
ProfessorA.Demenko ProfessorM.Rudan
Poznan´ UniversityofTechnology,Poznan´,Poland UniversityofBologna,Bologna,Italy
ProfessorE.Freeman ProfessorM.Sever
ImperialCollegeofScience,London,UK TheHebrewUniversity,Jerusalem,Israel
ProfessorSong-yopHahn ProfessorJ.Tegopoulos
SeoulNationalUniversity,Seoul,Korea NationalTechUniversityofAthens,Athens,Greece
ProfessorDr.-IngK.Hameyer ProfessorW.Trowbridge
KatholiekeUniversiteitLeuven,Leuven-Heverlee, VectorFieldsLtd,Oxford,UK
Belgium
ProfessorT.Tsiboukis
ProfessorN.Ida AristotleUniversityofThessaloniki,Thessaloniki,
UniversityofAkron,Akron,USA Greece
ProfessorA.Jack DrL.R.Turner
TheUniversity,NewcastleUponTyne,UK ArgonneNationalLaboratory,Argonne,USA
ProfessorA.Kost ProfessorDr.-IngT.Weiland
TechnischeUniversitatBerlin,Berlin,Germany TechnischeUniversitatDarmstadt,Darmstadt,
Germany
ProfessorT.S.Low
NationalUniversityofSingapore,Singapore ProfessorK.Zakrzewski
PolitechnikaLodzka,Lodz,Poland
COMPEL:TheInternationalJournal
forComputationandMathematicsin
ElectricalandElectronicEngineering,
Vol.21No.4,2002,p.500.
#MCBUPLimited,0332-1649
A current transformermodeling difficulty to evaluate accurately integrals for Abstracts and
YannLe Floch,Christophe Gue´rin, thecurrentdensitynearthecrack.Infact,due keywords
Dominique Boudaud, Ge´rard Meunier to the singular kernel of a dyadic Green
function, the integration is quasi-singular. A
andXavier Brunotte
specificregularisationalgorithmisdeveloped
Keywords Electrical circuits,
to overcome this problem and applied to
Transient flow,Nonlinearity, Magneticfields
represent eddy current distribution between
Thispaperpresentsthemodelingofacurrent two cracks. 501
transformer by various methods with the
FLUX3D software. The technique used is
Design ofphotonic bandgap optical
based on the finite element method coupled
fibers using finite elements
with electric circuits. A magnetic scalar
S.Guenneau, S.Lasquellec, A. Nicolet
potential reduced versus T formulation
0 and F.Zolla
(Tf2f) taking into account the electric
0
circuits with an air-gap is used for this Keywords Edgeelements,
purpose. The air-gap is described either by a Electromagnetism
thin volume region or bya surface region. Inthispaper,westudyanewclassofoptical
fibers to be utilized in future optics and
Achieving theholygrail ofseamless optoelectronics. These so-called photonic
CADdataimportintoanalysissoftware band gap (PBG) waveguides can be
classified into a fundamentally different way
J. Oakley,C.P. Riley,S.Taylor and
to all optical waveguides and possess
C.W. Trowbridge
radically different guiding properties due to
Keywords Computational methods, PBG guidance, as opposed to guidance by
Electromagnetics, Computer software,CAD total internal reflection.
One of the difficulties in electromagnetic
modelling has been the lack of standard Analysis oftechniques tocompare
CAD data to enable direct import of data complexdata sets
into analysis software. Many solid modelling
D.E. Coleby andA.P.Duffy
standardshavebeenproposedovertheyears,
butduetothemanyseparateinterestsinvolved Keywords Validation, Datacapture,
and differing geometrical requirements, a Correlation analysis
definitive standard has been elusive. Recently This paper analyses a number of techniques
theACISbasedSATformathasgainedfavour that can be used to compare complex data
andcanbeproducedbymanyproprietaryCAD sets,suchasthosearisingfromelectromagnetic
drawing packages. This paper exemplifies a simulationandexperimentation.Thetechniques
modern electromagnetic analysis tool that is assessed are: correlation, several reliability
abletodirectlyimportSATformatdata. factors and feature selective validation. The
study examines the performance of each
Application ofregularisation method technique for data comparison. The paper
ofquasi-singular integrals tocompute provides a comprehensive summary of the
eddy-current distributionnear cracks techniques and compares their performance
andcommentsontheiruseinthevalidationof
PhilippeBeltrame andNoel Burais
numericalmodellingcodesandmodeldesigns.
Keywords Eddycurrents,
Non-destructive testing, Evaluation
3-D eddy current computation for a
Forthincracks,ineddycurrenttesting(ECT), transformer tank
the field-flaw interaction is equivalent to a
Hiroshi Kanayama, RyujiShioya
currentdipolelayeronitssurface.Thedipole
Daisuke TagamiandSatoshi Matsumoto
densityisthesolutionofanintegralequation
with a hyperstrong kernel. The variation of Keywords Eddy currents, COMPEL:TheInternationalJournal
Domain decomposition method, A-method forComputationandMathematicsin
coil impedance and eddy current distribution ElectricalandElectronicEngineering,
is directly obtained from this density by a Alargescalecomputationofthree-dimensional Vol.21No.4,2002,
Abstractsandkeywords.
surface integration. There is a numerical eddy current problems is considered; their #MCBUPLimited,0332-1649
COMPEL numbers of degrees of freedom are near one alternativemethodtothefiniteelementandis
million. A parallel computing using the afilamentapproach.Experimentalresultsand
21,4
Hierarchical Domain Decomposition Method computation results using the proposed
(HDDM)is introduced tocompute large scale method arefoundto havegood agreement.
problems. Atransformer model is considered
as a numerical example, and HDDM is
Eddy currents inthinplates modelled
applicable to themodel.
as surface regions
502
Virgiliu Fireteanu,Bernard Paya,
Integration of controlloops incoupled Jacques NunsandTiberiu Tudorache
field circuitmodelto studymagnetic
Keywords Finite elementmethod,
devicessupplied by powerelectronic
Numerical methods, Modelling,
converter andtheir control
Eddy currents, Surface formulation
G.Manot, Y. Lef`evre, H.Piquet and
Thispaperanalyses theconditionsforwhich
F.Richardeau
the results of eddy currents computation in
Keywords Modelling, Magnetic fields, thin regions modelled by surface regions are
Control concordantwiththoseobtainedusingvolume
Inthispaper,wepresentamethodtotakeinto finiteelements.Theconceptsofgeometrically
account feedback control in software thin or thick region, electromagnetically thin
developed from coupled field circuit models. orthickregion,2Dor3Dproblem,transverse
The implementation of control loops is done or longitudinal flux problem are used to
in a software which is able to simulate characterise the limits of the surface model.
electromagnetic devices associated with The computation of eddy currents in sheets
power electronic circuits having a time heatedintransversefluxinductorsandofthe
dependent topology. The control strategy is eddy current losses in metallic casing of an
implemented in a discrete-time version and inductionfurnacehighlightsthesurfacefinite
can manage all controllable electronic element applicability.
switches by means of different electric or
magnetic quantities calculated during the
Field andcurrent flowanalysis of the
simulation (flux, currents, voltages, ...). buried feedingline oftheinnovative
Electrical systems involving magnetic
electric transport conceptSTREAM
devices, power electronic converters and
P. Alotto,F.Delfino, G.Molinari, M.Rossi,
their control devices can be similated in
V. SicilianoandP.O. Ventura
presence of phenomena such as eddy
currents or saturation of the magnetic Keywords Electrical machines, Transport,
material. 3D, Finite elementsimulation
STREAMistheacronymofanewconceptof
Calculation ofwinding losses using masstransitsystemdesignedanddevelopedby
matrixmodeling ofhigh frequency AnsaldoTrasportiS.p.A.toprovideanefficient
transformer solution to rubber-tyred transportation
problems in urban areas. One of STREAM’s
K.W.E. Cheng,K.F. Kwok,S.L.Ho and
most distinctive feature is the power supply
Y.L.Ho
system,whichusesamagneticliftcontactline
Keywords Eddycurrent loss, Transformer, embedded in the road surface to deliver
Filament traction power and to provide operating and
Calculation of the winding losses of high controlinformation.Inthispaperthefieldand
frequency transformer based on one- the current flow analyses of this buried
dimensional field analysis is normally feeding track are presented and discussed.
inapplicable for complex winding Analyses are aimed at determining the
configurations. This paper presents a matrix highest values of accessible voltages on the
modeling method which can produce a ground under different environmental and
generalized mechanism to solve the AC operating conditions. Results provided by a
winding losses. The transformer is modeled numerical simulation of the 3D model
in a matrix connected filament. This is an representing the feeding track allow us to
identify the most critical conditions and to is referring to a magnetostatic shield with Abstracts and
verifythesafetyandreliabilityofthesystem. double walls, designated to protect the
keywords
electronic data acquisition equipment when
Developments ofanefficient global is used in this environment. As introduction,
optimal design technique – a combined some features are presented and discussed
approach ofMLS and SAalgorithm for three models used in the field calculation
of magnetically polarised bodies and the
S.L.Ho, Shiyou Yang,Peihong Ni and
algorithm of iterative calculation in spaces 503
H.C. Wong
with sparse magneticbodies.
Keywords Surfaces, Model, Simulation,
Algorithms, Optimization
A new response surface model (RSM), the 3D-FDTD characterization ofan
movingleastsquares(MLS)approximation,is original low-loss silicon line
proposed for reconstructing the objective/
Alexandre Richardson, LaurentCirio,
constraint functions for the design
Laurent Martoglioand OdilePicon
optimization of electromagnetic devices. The
reconstructed functions are then combined Keywords Microstructures, Silicon
with the simulated annealing (SA) algorithm A numerical and experimental analysis of
to develop a computationally efficient an original inverted microstrip transmission
technique to obtain the global solutions. The line on standard Silicon substrate for
newmethodhas:theˆintelligence¤toarrange telecommunication applications is proposed.
the sample points, i.e. intensify the sample Simulations have been made using a time
points in regions where a local optimum is domain method such as Finite-Difference-
likely to exist; the flexibility in dealing with Time-Domain method (FDTD) to obtain
irregular sample points; the self-adaptive results on a large frequency band. However,
ability to regulate the parameters of the the main difficulty of the FDTD is due to
MLS models. Detailed numerical examples the absorbing boundary conditions (ABC)
aregiven tovalidate theproposed technique. which must be perfectly matched to the
inhomogeneous media with losses. Indeed,
Magnetic field around thealuminium thefinedimensionsprescribedbythestudied
electrolysis cells circuit lead to a long computational time. To
reduce the FDTD grid but also to simulate
AugustinMoraru, AureliuPanaitescu,
inhomogeneous medium with losses, an
IleanaPanaitescu, AntoinetaSoci
efficient and broadband ABC has to be
Keywords Magnetic fields,Magnetostatics implemented because classical ones are not
Twomagnetostatic applications arereported, suitabletosimulatealossysubstrate.Forthis
related to the magnetic field around the reason, a specific uniaxial perfectly matched
aluminium electrolysis cells. The first layers (UPML) is proposed. We compare
exhibits the magnetic field created by the numerical results obtained with FDTD, HP
current carrying parts in the cell Momentum and experimental ones to show
neighbourhood, by taking into account the the validation of the method applied to lossy
influence of the magnetic bodies. The second media.
COMPEL Introduction
21,4
The 13th COMPUMAG Conference on the Computation of Electromagnetic
504 Fields (July 2-5, 2001) was complemented – during the day immediately after
the Conference – by a TEAM Workshop and Application Forum. The aim of
the forum was to encourage and facilitate discussion on application problems
in numerical simulations of electromagnetic devices. The TEAM Workshop
andApplicationForumwereheldinaverypleasantplace:theVVFofEvian.
TEAMistheacronymfor‘‘TestingElectromagneticAnalysisMethods’’and
wasestablishedtovalidatetheeffectivenessofnumericaltechniques,basedon
developed benchmark problems. Existing ‘‘open’’ problems, as well as newly
proposedones,werediscussedduringtheTEAMWorkshopinEvian.
TogetherwiththeTEAMWorkshop,anApplicationForumwasorganized.
Duringanoralandapostersession,25papersrelatedtoindustrialapplications
of the numerical field computation were presented. Only papers dealing with
numerical methods were considered. The objective of the forum was to show
the impact of electromagnetic computation on the design of new industrial
devices.
Theauthorsofacceptedpaperswereinvitedtosubmitanextendedversion
for possible publication in COMPEL. These extended versions underwent a
newpeerreviewprocessinaccordancewiththerulesofCOMPEL.Aselection
of13papershavebeenacceptedandarepresentedinthisissue.
COMPEL:TheInternationalJournal
forComputationandMathematicsin
ElectricalandElectronicEngineering,
Vol.21No.4,2002,p.504.
#MCBUPLimited,0332-1649
Thecurrentissueandfulltextarchiveofthisjournalisavailableat
http://www.emeraldinsight.com/0332-1649.htm
A current transformer A current
transformer
modeling
modeling
Yann Le Floch
505
Cedrat Recherche, Meylan, France
Laboratoire d’Electrotechnique de Grenoble, Saint Martin d’H`eres,
France
Christophe Gue´rin
Cedrat Recherche, Meylan, France
Dominique Boudaud
Schneider Electric, Grenoble, France
Ge´rard Meunier
Laboratoire d’Electrotechnique de Grenoble, Saint Martin d’H`eres,
France, and
Xavier Brunotte
Cedrat Recherche, Meylan, France
KeywordsElectricalcircuits,Transientflow,Nonlinearity,Magneticfields
AbstractThispaperpresentsthemodelingofacurrenttransformerbyvariousmethodswiththe
FLUX3Dsoftware.Thetechniqueusedisbasedonthefiniteelementmethodcoupledwithelectric
circuits.AmagneticscalarpotentialreducedversusT formulationðT f2fÞtakingintoaccount
0 0
theelectriccircuitswithanair-gapisusedforthispurpose.Theair-gapisdescribedeitherbyathin
volumeregionorbyasurfaceregion.
1. Introduction
The study deals with a current transformer used in a low voltage circuit
breaker made by Schneider Electric (see Plate 1). FLUX3D software allows us
to take into account nonlinear transient magnetic problems coupled with
electriccircuits.Thissoftwareenablestomodelinaneffectivewaythecurrent
transformers by introducing a thin volume air-gap. This solution can be used
when modeling simple devices such as the current transformer presented in
this paper. When modeling more complex devices, difficulties due to the
geometricaldescriptionandthemeshingofthethinvolumeair-gapscanoccur.
Wewouldthenliketomodelthethinvolumeair-gapinanotherwaybyusing
shell elements which are surface elements with a thickness. Thus, a new
COMPEL:TheInternationalJournal
version which allows us to take into account electric circuits and surface air- forComputationandMathematicsin
ElectricalandElectronicEngineering,
gapshasbeendeveloped.Wewilldescribetheimprovementsobtained,thanks Vol.21No.4,2002,pp.505-511.
to the introduction of a surface air-gap with the electric circuits. qMCBUPLimited,0332-1649
DOI10.1108/03321640210437761
COMPEL
21,4
506
Plate1.
Thecurrenttransformer
usedforthemodeling
2. Description of the current transformer
The transformer is constituted by a magnetic core surrounded by two
secondary coils connected in series. The finite element modeling (in time
stepping and circuit equations) represents 1/8th of the device (see Figure 1).
The simulated curves correspond to a primary sinusoidal excitation ðI ¼
0
11;137Aandf ¼ 50HzÞandapurelyresistiveload.Thetotalsimulationtime
(40ms) corresponds to the transient mode of the sensor.
3. Formulation: T f2f
0
The present formulation ðT f2fÞ (Biro et al., 1993; Meunier et al., 1998) to
0
treat couplings between electric circuits and magnetic devices is shown in
Figure 2.
Figure1.
Descriptionofthe
currenttransformer
In magnetic circuit (V): A current
t
transformer
H ¼ 2gradðfÞ B ¼mH
modeling
In air and in air-gap (V )
0
507
X
H ¼ I t 2gradðfÞ B ¼mH
k 0k 0
k¼1;m
where m is the number of inductors.
t iscalculatedintheV regionwithaunitcurrentintheinductork,suchas:
0k 0
t £n ¼ 0 on G ¼ V >V
0k t 0
With this assumption, the relation between current and voltage is (Piriou and
Razek, 1992):
Z ›B
U ¼ R I þ t · dV
k k k 0k
›t
V0
To compute t , we have two solutions. The first solution is to use edge
0k
elements, which is natural in order to take into account the surface condition
t £n ¼ 0 on G. The other one is to compute nodal t . For this purpose, we
0k 0k
compute t in the air (V ) such as
0k 0
t ¼ h 2gradðdfÞ
0k 0k k
whereh isthemagneticfieldduetoaunitcurrentintheinductork,calculated
0k
with Biot and Savart’s formula (nodal value) in the air (V ),df the reduced-
0 k
total increment (Simkin and Trowbridge, 1979; Luong et al., 1996) calculated
with a unit current in the inductor k such as: gradðdfÞ£n ¼ h £n on
k 0k
G ¼ V >V :
t 0
Figure2.
FormulationT f2f
0
configuration
