bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of critical thermal operations for high‐speed permanent magnet electrical machines
Authors: Kolondzovski Zlatko 
Published: August 2008

PurposeThe thermal design of high‐speed electrical machines is a greater challenge in comparison with conventional electrical machines. When designing the machine, the calculated temperatures in all parts should be lower than their critical temperatures. This paper aims to perform thermal analysis for different rotor types according to the level of shield from eddy currents in order to achieve a safe thermal design of the machine.Design/methodology/approachThe machine under study in the paper is a high‐speed permanent magnet (PM) motor designed for speed n=31,500 rpm and power P=130 kW. A thermal‐network method was used for thermal analysis of the machine.FindingsThe minimum value of the coolant flow in the air gap that provides an effective cooling of the machine was estimated. The coolant itself is not able to provide an effective cooling of the magnets if they are not shielded from eddy currents.Research limitations/implicationsThe results are obtained only by the thermal‐network method. Numerical techniques and practical measurements for comparison and validation of the existing results should be implemented in future.Practical implicationsThe paper offers useful practical information when a safe thermal design of a high‐speed PM electrical machine should be performed.Originality/valueThe paper demonstrates how three different design types of a high‐speed PM electrical machine are thermally analysed in order to find out which type fulfils the rigorous thermal criteria. The practical significance of the paper is beneficial for the designers of high‐speed PM electrical machines.
High frequency electromagnetic emissions of cylindrical laminated cores
Authors: Duchesne Stéphane , Lecointe J‐Ph. , Périsse F. , Napieralska‐Juszczak Ewa 
Published: August 2008

PurposeThis paper aims to propose a high‐frequency (HF) model able to compute the flux density in the vicinity of the laminated stator core of an AC machine.Design/methodology/approachExperiments form the main approach. Analytical results previously obtained with a simplified rectangular laminated structure are confirmed with a standard cylindrical magnetic core.FindingsThree frequency domains are defined, depending on the skin depth relative to the thickness of the magnetic sheets. A methodological approach is proposed for each domain. For higher frequencies, the magnetic core can be considered as transparent for external field computation.Research limitations/implicationsThe HF model is valid for skin depths much lower than the thickness of the magnetic sheets.Practical implicationsThe proposed HF model provides a link between the weak field measured in the natural void existing between the stator core and the housing of large electrical machines. With such a link, it is possible to develop a new monitoring system able to detect and to localize the partial discharges in the stator winding of a large machine.Originality/valueThe low‐frequency limit of the model has been measured. It corresponds to a ratio of 1/40 between the skin depth and the magnetic sheet thickness. Therefore this model offers a new perspective for maintenance applications.
Attenuation of magnetic field components through an AC machine stator
Authors: Thailly D. , Romary R. , Roger D. , Brudny J‐F. 
Published: August 2008

PurposeNon‐intrusive magnetic measurements in AC machines are possible with small flat coils stuck on the external surface of the housing of a running motor. The aim of the paper consists in determining transmission coefficients able to give a direct relationship between the weak external flux density and the airgap one.Design/methodology/approachAn experimental approach shows that the decoupling principle can be applied. Transmission coefficients are determined separately for the stator yoke, the motor housing and the external air.FindingsFor low frequencies and a housing made of steel, eddy current can be neglected. The transmission coefficient depends strongly of the mode (number of poles) of the rotating field. Conversely, for higher harmonic ranks, the additional attenuation caused by eddy currents in the housing does not practically depend on the mode but is strongly dependant on the frequency.Research limitations/implicationsThe transmission coefficients are determined considering a 2D electromagnetic model and several simplifying hypothesis. Experiments prove the validity of the proposed approach up to 550 Hz.Practical implicationsUp to now, many fault detection systems are based on the presence of additional harmonics in the external magnetic field spectrum. With the knowledge of simple transmission coefficients, an analysis of the variation of the magnitude of critical spectrum lines is now possible for a more precise fault detection in AC machines.Originality/valueTo the authors' knowledge, the only alternative way for the interpretation of external field measurements consist in using a numerical method with a full model of the machine which takes a lot of computation time. The proposed transmission coefficients provide a faster method valid for most of the interesting spectrum lines.
3D finite element analysis of skewed squirrel‐cage induction motor using novel mesh modification method
Authors: Kawase Yoshihiro , Yamaguchi Tadashi , Watanabe Masashi , Toida Naotaka , Zhipeng Tu , Minoshima Norimoto 
Published: August 2008

PurposeThis paper aims to describe a novel 3D finite element mesh modification method for motors with the skewed rotor in detail, the method having been developed by solving the Laplace equation.Design/methodology/approachUsing the mesh of the skewed squirrel‐cage induction motor created by the novel method, the torque, the bar‐current, the electrical losses and so on are analyzed by the 3D finite element method.FindingsIt was found that the torque ripple, the bar‐current ripple and the losses of the motor with the skewed rotor are smaller than those of the motor with the no‐skewed rotor. In addition, the validity of the analysis is clarified by comparing the calculated and the measured results.Originality/valueThe usefulness of the method is clarified by the 3D finite element analysis of a skewed squirrel‐cage induction motor.
Three‐phase distributed constants model of induction machines for EMC and surge propagation studies
Authors: Della Torre Francesco , Leva Sonia , Paolo Morando Adriano 
Published: August 2008

PurposeThis paper aims to provide a complete three‐phase distributed constants model of cable‐induction machine systems useful for EMC and overvoltages propagation studies.Design/methodology/approachThe paper considers a three‐phase distributed constants model for the supply cable and a model of the same type for the induction machine. All the magneto‐electric links between phases are considered. The Clarke transform is applied in order to reduce the analytical complexity of the obtained model. A new numerical method is also proposed for the integration of the resulting whole three‐phase model, very similar, in terms of methodology, to the well‐known finite differences models.FindingsThe whole model for the three‐phase drives is used for EMC and overvoltages propagation studies. The proposed examples highlight how, thanks to the Clarke model, the dynamic analysis of the three‐phase drives in case of application of a standard fault source or an equivalent pulse width modulation (PWM) impulse, become easy to implement on a standard PC and with standard software (i.e. Matlab). The obtained results, compared with those that are presented in the literature, confirm the validity of the proposed model and numerical approach.Originality/valueThe developed model is of a three‐phase type because it is not possible to consider a single‐phase equivalent model in case of asymmetric voltage sources (i.e. asymmetric faults or PWM inverter voltage supply). The model also includes all the magneto‐electric couplings between phases that play a fundamental role in the considered applications.
Geometrical transformations and equivalent materials in computational electromagnetism
Authors: Nicolet A. , Zolla F. , Ould Agha Y. , Guenneau S. 
Published: August 2008

PurposeThis paper aims to review various techniques used in computational electromagnetism such as the treatment of open problems, helicoidal geometries and the design of arbitrarily shaped invisibility cloaks. This seemingly heterogeneous list is unified by the concept of geometrical transformation that leads to equivalent materials. The practical set‐up is conveniently effected via the finite element method.Design/methodology/approachThe change of coordinates is completely encapsulated in the material properties.FindingsThe most significant examples are the simple 2D treatment of helicoidal geometries and the design of arbitrarily shaped invisibility cloaks.Originality/valueThe paper provides a unifying point of view, bridging several techniques in electromagnetism.
Models for integrated components coupled with their EM environment
Authors: Ioan Daniel , Schilders Wil , Ciuprina Gabriela , van der Meijs Nick , Schoenmaker Wim 
Published: August 2008

PurposeThe main aim of this study is the modelling of the interaction of on‐chip components with their electromagnetic environment.Design/methodology/approachThe integrated circuit is decomposed in passive and active components interconnected by means of terminals and connectors which represent intentional and parasitic couplings of a capacitive and inductive nature. Reduced order models are extracted independently for each component.FindingsThe paper shows that one of the main theoretical problems encountered in the modelling of RF components is the difficulty to define a unique terminal voltage, independent of the integration path (this independence being a condition to allow the connection of the component in an electric circuit, where the voltage does not depend of the path shape). The concept of an electromagnetic circuit element that allows the interconnection between IC models is proposed as a solution for this drawback. The system is described either with EM field models, or by electric/magnetic circuits. By using the new concept of hooks, the EM interaction is described effectively with a reduced number of quantities.Research limitations/implicationsSince hooks have a virtual character, their identification is the result of an optimization procedure. By increasing their number the model accuracy is improved as also is the computational effort. The optimal automatic identification of electric and magnetic hooks is the subject of further research. Currently, the hooks are placed manually.Practical implicationsThe modelling of IC components with hooks is part of a new methodology that takes a layout description of typical RF functional blocks that will operate at RF frequencies up to 60 GHz and transform them into sufficiently accurate, reliable electrical simulation models, taking EM coupling and variability into account. This will decrease extra design iterations, over‐dimensioning or complete failures in the design cycle of RF‐IC.Originality/valueFor the first time, the concept of magnetic terminals is used to describe interactions in RF integrated circuits. These EM “hooks” are defined in mathematical terms, as proper boundary conditions. The concept of hooks is also new. The proposed modeling methodology for EM coupling is also new. The paper is useful for nEDA designers.
Steady‐state performance analysis for hysteresis motor with magnetic anisotropy
Authors: Kurihara Kazumi , Kubota Tomotsugu 
Published: August 2008

PurposeThe purpose of this paper is to present a novel steady‐state performance analysis for the hysteresis motor whose rotor ring is made of Fe‐Cr‐Co magnet steel with magnetic anisotropy.Design/methodology/approachIn order to analyze the motor performance at synchronous pull‐out, the finite‐element method is used, where hysteresis torque is obtained from the magnetic field analysis of the hysteresis motor with the isotropic magnet. The reluctance torque due to magnetic anisotropy can be obtained by using the difference of the B‐H hysteresis‐loop area between the anisotropic and isotropic magnets.FindingsThe good agreement between computed and measured performance in an experimental motor validates the proposed analysis.Originality/valueThe proposed method is quite useful for the design and analysis of the hysteresis motor with magnetic anisotropy.
Scalarizing cost‐effective multi‐objective optimization algorithms made possible with kriging
Authors: Hawe Glenn , Sykulski Jan 
Published: August 2008

PurposeThe purpose of this paper is threefold: to make explicitly clear the range of efficient multi‐objective optimization algorithms which are available with kriging; to demonstrate a previously uninvestigated algorithm on an electromagnetic design problem; and to identify algorithms particularly worthy of investigation in this field.Design/methodology/approachThe paper concentrates exclusively on scalarizing multi‐objective optimization algorithms. By reviewing the range of selection criteria based on kriging models for single‐objective optimization along with the range of methods available for transforming a multi‐objective optimization problem to a single‐objective problem, the family of scalarizing multi‐objective optimization algorithms is made explicitly clear.FindingsOne of the proposed algorithms is demonstrated on the multi‐objective design of an electron gun. It is able to identify efficiently an approximation to the Pareto‐optimal front.Research limitations/implicationsThe algorithms proposed are applicable to unconstrained problems only. One future development is to incorporate constraint‐handling techniques from single‐objective optimization into the scalarizing algorithms.Originality/valueA family of algorithms, most of which have not been explored before in the literature, is proposed. Algorithms of particular potential (utilizing the most promising developments in single‐objective optimization) are identified.
Modelling and simulation of stator winding inter‐turn faults in permanent magnet synchronous motors
Authors: Ahmed Farooq Jawad , Raminosoa Tsarafidy , Djerdir Abdesslem , Miraoui Abdellatif 
Published: August 2008

PurposeThe purpose of this paper is to present a new model to study inter‐turn short circuit faults in a permanent magnet synchronous machine.Design/methodology/approachThe machine is modeled by using classical two‐axis theory, and the equations are modified to take into account the stator inter‐turn faults. A state space form of the system is presented for dynamic simulations.FindingsThe machine model is global and can work in both normal and fault conditions due to a fictitious resistance in the winding circuit. Various simulation results have been presented indicating the fault instant and its corresponding effect. Validation is carried out by transient time finite element simulations.Originality/valueThe model can serve as a step towards development of fault detection and diagnosis algorithms.
Spectral analysis of permanent magnet electric machines
Authors: Witczak Pawel , Wawrzyniak Beata 
Published: August 2008

PurposeThis paper aims to provide the mathematical background for representation of permanent magnet AC machines in terms of rotating magnetic field waves of any shape instead of being restricted to the sinusoidal. The general idea is to replace the inductances in the mathematical model of the machine by means of adequate time functions of the flux linkage.Design/methodology/approachOn the basis of several 2D or 3D solutions obtained by the finite element (FE) approach, the set of basis functions is generated for further post‐processing. These functions enable fast and accurate computations of back EMF time shape at any load conditions, which in turn gives the instantaneous values of terminal quantities like torque or voltage, depending on the regime of interest.FindingsThe permanent magnet machine (PMM) has been represented by means of the traveling non‐dispersive waves of the flux density in the air gap rotating with specified group velocity. The conversion between distributions of the flux density in space and flux linkage in time is obtained through filtering in the spectral domain using 2D or 3D discrete Fourier transform. The change of magnetic saturation due to arbitrary value of the machine load is incorporated by the interpolation between known magnitudes of the basis functions at given a priori RMS values of phase currents. It has been proved that a sinusoidal field machine is particular to the presented theory.Research limitations/implicationsThe paper deals with the steady state of PMM; however, the extension towards the transient analysis is possible.Practical implicationsThe paper presents a fast and accurate model of PMM for the analysis of its basic electromagnetic quantities.Originality/valueThe analysis of terminal quantities being different in time from sinusoidal or constant distributions, both electrical and mechanical, is usually performed by means of a time stepping approach. The required computing effort is still too high for real time applications. The presented method starts from single FE solutions and converts their accuracy on the set of mutually orthogonal functions having the clear representation in the spectral, mode‐frequency domain. The magnitudes of these basic functions enable one to express the electromagnetic power in a form equivalent to classic dq representation, but not constrained by sinusoidal input quantities.
Permanent magnet synchronous motors
Authors: Donsión M.P. 
Published: August 2008

PurposeThis paper aims to apply a two‐axis model for accurate representation of the characteristics of permanent magnet synchronous motors (PMSM) of the interior type.Design/methodology/approachFor a three‐phase PMSM, it uses a voltage source inverter with six power transistors with independent switching and PSIM software with Matlab for checking, by simulation, how some parameters influence the start process.FindingsIt was found that pulsating components generate the synchronizing torque.Originality/valueThe paper provides a model for accurate representation of the characteristics of permanent magnet motors.
A new method of biomolecular recognition of avidin by light scattering of ZnS:Mn nano‐particles
Authors: Rabiee M. , Mirhabibi A.R. , Moztar Zadeh F. , Aghababazadeh R. , Mohaghegh Pour E. , Lin L. 
Published: August 2008

PurposeThe purpose of this paper is to develop a new method for biomolecular recognition based on light scattering of ZnS:Mn nano‐particle functionalised with biotin.Design/methodology/approachZnS:Mn nano‐particles was successfully synthesised from quaternary water‐in‐oil micro‐emulsion system. The addition of biotin and the subsequent specific binding events alter the dielectric environment of the nano‐particle, resulting in a spectral shift of the particle plasmon resonance. Cyclohexane was used as oil, Triten X‐100 as surfactant, n‐hexanol as a co‐surfactant and mercaptoethanol for the best linking of biological part to nano‐particle. Measurement of the content of avidin was achieved by detecting the Department of Biomedical Engineering change in the excited emission. For qualitative and quantitative analyses of this product, scanning electron microscopy, transmission electron microscopy, energy dispersive X‐ray spectroscopy and spectrograph techniques were used.FindingsIt was observed that with reducing particle size, emission shifted to the lower wave lengths. In addition, with conjugation between avidin and biotin by mercaptoethanol in biologic media, spectral emission decreased.Practical implicationsThe method developed could be utilised for synthesis of a variety of ZnS:Mn nano‐particles for a wide range of diagnostic applications.Originality/valueThe method for biomolecular recognition based on light scattering of ZnS:Mn nano‐particle functionalised with biotin developed was novel.
A novel natural adhesive from rice bran
Authors: Wang W.H. , Zhang X.Q. , Li X.P. 
Published: August 2008

PurposeThe purpose of this paper is to investigate a new approach for making a bio‐based adhesive from a new resource, rice bran (RB) adhesive.Design/methodology/approachRB solution was prepared and its pHs were adjusted to either 8.5‐9.0 or 10.0‐10.5. The solid content of slurry was controlled at ≈18 per cent and then gelatinised in a water bath shaker at 60°C for 2 h or at 100°C for 1 h. The bonding strength of RB adhesive was determined by testing the strength of three‐layer plywood. A differential scanning calorimeter (DSC) was used for detecting the reaction energy and curing temperature. According to the DSC analysis, hot pressing at three temperatures was performed to select the best bonding conditions. Then, a two level split‐plot design was used to determine the effects of gelatinisation and pH on the bonding strength of RB adhesive. Thus, the formulation of RB adhesive was optimised. In order to improve the water resistance of RB adhesive, toluene diisocyanate (TDI) was used as a cross linking agent.FindingsIn the study reported here, a RB adhesive was developed by alkaline modification. Very high pH was not necessary, when RB adhesive with pH 10.0‐10.5 was gelatinised at 100°C for 1 h, its bonding strength was significantly lower than pH 8.5‐9.0 gelatinised at 60°C for 2 h. Water resistance of RB adhesive improved significantly when TDI was added as a cross linking agent. Compared to pure RB adhesive, the RB‐TDI mixed adhesive started curing at a higher temperature. For RB adhesive curing, 130°C was a suitable hot pressing temperature.Research limitations/implicationsThough the RB adhesive developed had a good bonding strength, its water resistance and dark colour was not satisfactory, which risks discolour of light colour wood. Further study is needed to solve this problem.Practical implicationsThe approach provided a bio‐adhesive with good bonding strength, reasonable working life, and without formaldehyde emission. Based on further study, RB adhesive could be considered a promising alternate adhesive in many applications such as paper board bonding and plywood.Originality/valueIt provided a potential way to utilise by‐product of agriculture, RB as industrial raw material. This will do farmers a great favour. Meanwhile, the modified RB adhesive is promising to partly or completely replace urea formaldehyde resin that mainly used in wood industry, avoiding formaldehyde emission and reducing the dependence on petroleum products.