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Article
Publication date: 1 June 2004

B. Butrylo, F. Musy, L. Nicolas, R. Perrussel, R. Scorretti and C. Vollaire

This paper presents new trends in parallel methods used to solve finite element matrix systems: standard iterative and direct solving methods first, and then domain decomposition…

734

Abstract

This paper presents new trends in parallel methods used to solve finite element matrix systems: standard iterative and direct solving methods first, and then domain decomposition methods. For example, the current status and properties of two prevailing programming environments (PVM and MPI) are finally given and compared when implemented together with a finite element time domain formulation.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 23 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 June 2003

Jaroslav Mackerle

This paper gives a bibliographical review of the finite element and boundary element parallel processing techniques from the theoretical and application points of view. Topics…

1558

Abstract

This paper gives a bibliographical review of the finite element and boundary element parallel processing techniques from the theoretical and application points of view. Topics include: theory – domain decomposition/partitioning, load balancing, parallel solvers/algorithms, parallel mesh generation, adaptive methods, and visualization/graphics; applications – structural mechanics problems, dynamic problems, material/geometrical non‐linear problems, contact problems, fracture mechanics, field problems, coupled problems, sensitivity and optimization, and other problems; hardware and software environments – hardware environments, programming techniques, and software development and presentations. The bibliography at the end of this paper contains 850 references to papers, conference proceedings and theses/dissertations dealing with presented subjects that were published between 1996 and 2002.

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Engineering Computations, vol. 20 no. 4
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 19 July 2022

Yasuhito Takahashi, Koji Fujiwara and Takeshi Iwashita

This study aims to enhance the parallel performance of a parallel-in-space-and-time (PinST) finite-element method (FEM) using time step overlapping. The effectiveness of the…

54

Abstract

Purpose

This study aims to enhance the parallel performance of a parallel-in-space-and-time (PinST) finite-element method (FEM) using time step overlapping. The effectiveness of the developed method is clarified in a magnet eddy-current loss analysis of a practical interior permanent magnet synchronous motor (IPMSM) using a massively parallel computing environment.

Design/methodology/approach

The developed PinST FEM is a combination of the domain decomposition method as a parallel-in-space (PinS) method and a parallel time-periodic explicit error correction (PTP-EEC) method, which is one of the parallel-in-time (PinT) approaches. The parallel performance of the PinST FEM is further improved by overlapping the time steps with different processes in the PTP-EEC method.

Findings

By applying the overlapping PTP-EEC method, the convergence of the transient solution to its steady state can be accelerated drastically. Consequently, the good parallel performance of the PinST FEM is achieved in magnetic field analyses of the practical IPMSM using a massively parallel computing environment, in which over 10,000 processes are used.

Originality/value

In this study, the PinST FEM based on time step overlapping is newly developed and its effectiveness is demonstrated in a massively parallel computing environment, in which using either the PinS or PinT method alone cannot achieve sufficient parallel performance. This finding implies a new direction of parallel computing approaches for electromagnetic field computation.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 42 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 10 April 2007

G.B. Kumbhar, S.V. Kulkarni, R. Escarela‐Perez and E. Campero‐Littlewood

This paper aims to give a perspective about the variety of techniques which are available and are being further developed in the area of coupled field formulations, with selective…

1245

Abstract

Purpose

This paper aims to give a perspective about the variety of techniques which are available and are being further developed in the area of coupled field formulations, with selective bibliography and practical examples, to help postgraduate students, researchers and designers working in design or analysis of electrical machinery.

Design/methodology/approach

This paper reviews the recent trends in coupled field formulations. The use of these formulations for designing and non‐destructive testing of electrical machinery is described, followed by their classifications, solutions and applications. Their advantages and shortcomings are discussed.

Findings

The paper gives an overview of research, development and applications of coupled field formulations for electrical machinery based on more than 160 references. All landmark papers are classified. Practical engineering case studies are given which illustrate wide applicability of coupled field formulations.

Research limitations/implications

Problems which continue to pose challenges to researchers are enumerated and the advantages of using the coupled‐field formulation are pointed out.

Practical implications

This paper gives a detailed description of the application of the coupled field formulation method to the analysis of problems that are present in different electrical machines. Examples of analysis of generators and transformers with this formulation are presented. The application examples give guidelines for its use in other analyses.

Originality/value

The coupled‐field formulation is used in the analysis of rotational machines and transformers where reference data are available and comparisons with other methods are performed and the advantages are justified. This paper serves as a guide for the ongoing research on coupled problems in electrical machinery.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 26 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 7 September 2015

Tomonori Tsuburaya, Yoshifumi Okamoto and Shuji Sato

The purpose of this paper is to improve the performance of block-multicolor (BMC) ordering for the parallelized incomplete-Cholesky-preconditioned conjugate gradient (ICCG…

77

Abstract

Purpose

The purpose of this paper is to improve the performance of block-multicolor (BMC) ordering for the parallelized incomplete-Cholesky-preconditioned conjugate gradient (ICCG) method. Then, the BMC ordering based on level structure arising in reverse Cuthill-McKee RCM ordering is newly proposed. The name of proposed method is abbreviated as “RBMC”. This paper shows the validity of proposed method by comparison with greedy-based multicolor (MC) and conventional BMC on the real symmetric linear system derived from the voltage-driven finite element method in time domain.

Design/methodology/approach

In RBMC, the blocking and coloring is performed level by level. The number of synchronizations in forward and backward substitution is reduced so that all blocks can be colored with two colors. However, the load-balance in forward and backward substitution might deteriorate because the irregular block matrices are distributed around diagonal. To uniformize load-balance in forward and backward substitution, the RBMC combined with the concept of block red-black ordering has been developed.

Findings

The modified RBMC was the most effective for reduction of the elapsed time among four orderings (MC, BMC, RBMC, modified RBMC) owing to improvement of convergence characteristic and load-balance.

Originality/value

The proposed method had two advantages: although the number of unknowns per block must be previously determined in BMC, its parameter is automatically determined in proposed method, the number of synchronization in forward and backward substitution can be reduced.

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COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 5
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 23 September 2024

Gauthier Derenty-Camenen, Alexis Lepot, Olivier Chadebec, Olivier Pinaud, Laure-Line Rouve and Steeve Zozor

The purpose of this paper is to propose a compact model to represent the magnetic field outside the sources. This model provides the multipolar ordering of a spherical harmonic…

11

Abstract

Purpose

The purpose of this paper is to propose a compact model to represent the magnetic field outside the sources. This model provides the multipolar ordering of a spherical harmonic expansion far from the source while being valid in its close proximity.

Design/methodology/approach

The authors investigate equivalent surface sources that enable to compute the field very close to any chosen surface that encloses the source. Then the authors present a method to find an appropriate initial basis and its associated inner product that allow to construct multipolar harmonic bases for these equivalent sources, where any vector of order k produces a field that decreases at least as fast as the field produced by a multipole of order k. Finally, those bases are numerically implemented to demonstrate their performances, both far from the source and in its close proximity.

Findings

The charge distribution and normal dipole distribution are well-suited to construct multipolar harmonic bases of equivalent sources. These bases can be described by as few parameters as the decreasing spherical harmonic expansion. Comparison with other numerical models shows its ability to compute the field both far from the source and close to it.

Originality/value

A basis for normal dipole distribution has already been described in the literature. This paper presents a general method to construct a multipolar basis for equivalent sources and uses it to construct a basis for single-layer potential.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 43 no. 6
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 5 January 2010

Thomas Weidinger

The purpose of this paper is to present an analysis of common mode oscillations of several kilohertz in electrical drive systems. The analysed oscillations occur especially in…

290

Abstract

Purpose

The purpose of this paper is to present an analysis of common mode oscillations of several kilohertz in electrical drive systems. The analysed oscillations occur especially in electrical drive systems with active front end (AFE), common DC link and long motor cables and are independent of the well‐known reflection phenomenon. Owing to the resulting overvoltages, the motor isolation lifetime may be significantly reduced.

Design/methodology/approach

For the analysis of the described problem, all parts of the common mode system of an electrical drive system are carefully modelled. This leads to an analysis of the frequency behaviour of the common mode system. The excitation mechanisms are also analysed and simulation in the time domain is performed to show the resulting overvoltages. Finally, measurements confirm the findings.

Findings

The investigations identified the reasons for the oscillations: the common mode system behaviour, including the common mode resonant behaviour of some special kinds of motor. Furthermore, the excitation mechanism is found to be dependent on the modulation schemes of the AFE and the inverters. Accordingly, a special remedy concerning the modulation is derived and compared to other known remedies. The results of the simulations show the good efficiency of the proposed remedy.

Originality/value

The presented results describe important basics for the development of electrical drive systems. By taking these issues into consideration, many unpredictable failures can be avoided.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 29 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 3 August 2021

Sumathy P., Navamani Divya, Jagabar Sathik, Lavanya A., Vijayakumar K. and Dhafer Almakhles

This paper aims to review comprehensively the different voltage-boosting techniques and classifies according to their voltage gain, stress on the semiconductor devices, count of…

236

Abstract

Purpose

This paper aims to review comprehensively the different voltage-boosting techniques and classifies according to their voltage gain, stress on the semiconductor devices, count of the total components and their prominent features. Hence, the focus is on non-isolated step-up converters. The converters categorized are analyzed according to their category with graphical representation.

Design/methodology/approach

Many converters have been reported in recent years in the literature to meet our power requirements from mill watts to megawatts. Fast growth in the generation of renewable energy in the past few years has promoted the selection of suitable converters that directly impact the behaviour of renewable energy systems. Step-up converters are a fast-emerging switching power converter in various power supply units. Researchers are more attracted to the derivation of novel topology with a high voltage gain, low voltage and current stress, high efficiency, low cost, etc.

Findings

A comparative study is done on critical metrics such as voltage gain, switch voltage stress and component count. Besides, the converters are also summarized based on their advantages and disadvantages. Furthermore, the areas that need to be explored in this field are identified and presented.

Originality/value

Types of analysis usually performed in dc converter and their needs with the areas need to be focused are not yet completely reviewed in most of the articles. This paper gives an eyesight on these topics. This paper will guide the researchers to derive and suggest a suitable topology for the chosen application. Moreover, it can be used as a handbook for studying the various topologies with their shortfalls, which will provide a way for researchers to focus.

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Article
Publication date: 17 March 2014

Sheng Li, Xinhua Yao and Jianzhong Fu

For using wireless sensors to monitor spindle units without opening the spindle shell to replace the battery, harvesting the waste heat from spindle units of machine tools for…

236

Abstract

Purpose

For using wireless sensors to monitor spindle units without opening the spindle shell to replace the battery, harvesting the waste heat from spindle units of machine tools for thermoelectric generation to drive wireless sensors is studied in this paper. The paper aims to discuss these issues.

Design/methodology/approach

In this paper, the thermal network method and the analogies between electrical and thermal domains are used in the simulation of power output performance of thermoelectric generation on a rotating spindle. After that, experiments are done to obtain the real power output performance of the generation and evaluate the feasibility to drive wireless sensors.

Findings

The paper provides that the output voltage of the thermoelectric generations was nearly linear with the rotating speed of the spindle, the output voltage was sensitive to the fixed position of the generations, and the thermoelectric system could drive the wireless sensor well most of the time during continuous operation of the spindle.

Research limitations/implications

It is found that the thermoelectric generation could not provide enough power in the early start-up stage of the spindle rotation, so a high-efficiency power manage system, which will be studied in the future research, is needed to handle this problem.

Practical implications

The paper includes implications for the development of self-powered wireless sensors in the spindle unit for machine tool monitoring.

Originality/value

The paper develops a model of the power output performance of thermoelectric generation on a rotating spindle and tests the feasibility to drive wireless sensors with this power.

Details

Sensor Review, vol. 34 no. 2
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 21 August 2018

Polyanna Mara Pereira, Felipe Campelo, Takuya Mori, Hajime Igarashi and Ricardo Adriano

This paper aims to present a SPICE model to represent antennas in receiving mode. The model can be used to evaluate the performance of the antenna when it is coupled to several…

143

Abstract

Purpose

This paper aims to present a SPICE model to represent antennas in receiving mode. The model can be used to evaluate the performance of the antenna when it is coupled to several different nonlinear electric circuits. The proposed methodology is particularly suitable for rectenna applications, as it allows the analysis of different configurations for a rectenna more efficiently than using full-wave analysis simulators coupled directly to each rectifier circuit.

Design/methodology/approach

The model presented uses reciprocity theory to calculate the ideal voltage source of the Thevenin-equivalent circuit for an antenna. Vector fitting is then used to approximate the model to rational functions that can be converted to Resistor, Inductor and Capacitor circuits. Additional components are added to the circuit to prevent numerical instability.

Findings

Two rectennas are used to illustrate the performance of the proposed model, one based on a 2.45-GHz rectangular patch antenna and another based on a planar spiral antenna. The second antenna has impedance with positive and negative real parts along the frequency range, which could lead to numerical instabilities. The proposed method is shown to be stable while working with these negative resistance values, which may appear during circuit parameterization.

Research limitations/implications

The equivalent SPICE circuit model for the antenna makes it easy to simulate nonlinear circuits connected to the antenna and perform transient analyses. The computational cost of antenna analysis is reduced, being more computationally efficient than methods that involve full-wave simulation. This characteristic makes it an interesting approach for working with rectennas, or any application where the time constant of the circuit is much longer than the period of the incident wave.

Originality/value

For most antenna applications, the numerical stability of the circuit can be achieved using passive enforcement. However, depending on the phase response of the antenna, the impedance that represents its far-field characteristic may present a negative real part, in which case, passive enforcement will fail. In this paper, the problem of numerical instability is solved by introducing an offset resistance and a current-controlled voltage source to the model.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

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