bluuebunny/crossref_metadata_2025_split huggingface dataset:
A polynomial chaos meta‐model for non‐linear stochastic magnet variations
Authors: Offermann Peter , Hameyer Kay 
Published: July 2013

PurposeDue to the production process, arc segment magnets with radial magnetization for surface‐mounted permanent‐magnet synchronous machines (PMSM) can exhibit a deviation from the intended ideal, radial directed magnetization. In such cases, the resulting air gap field may show spatial variations in angle and absolute value of the flux‐density. For this purpose, this paper aims to create and evaluate a stochastic magnet model.Design/methodology/approachIn this paper, a polynomial chaos meta‐model approach, extracted from a finite element model, is compared to a direct sampling approach. Both approaches are evaluated using Monte‐Carlo simulation for the calculation of the flux‐density above one sole magnet surface.FindingsThe used approach allows representing the flux‐density's variations in terms of the magnet's stochastic input variations, which is not possible with pure Monte‐Carlo simulation. Furthermore, the resulting polynomial‐chaos meta‐model can be used to accelerate the calculation of error probabilities for a given limit state function by a factor of ten.Research limitations/implicationsDue to epistemic uncertainty magnet variations are assumed to be purely Gaussian distributed.Originality/valueThe comparison of both approaches verifies the assumption that the polynomial chaos meta‐model of the magnets will be applicable for a complete machine simulation.
A posteriori error estimator for harmonic A‐φ formulation
Authors: Tang Zuqi , Le Menach Yvonnick , Creuse Emmanuel , Nicaise Serge , Piriou Francis , Nemitz Nicolas 
Published: July 2013

PurposeIn this paper, the aim is to propose a residual‐based error estimator to evaluate the numerical error induced by the computation of the electromagnetic systems using a finite element method in the case of the harmonic A‐φ formulation.Design/methodology/approachThe residual based error estimator used in this paper verifies the mathematical property of global and local error estimation (reliability and efficiency).FindingsThis estimator used is based on the evaluation of quantities weakly verified in the case of harmonic A‐φ formulation.Originality/valueIn this paper, it is shown that the proposed estimator, based on the mathematical developments, is hardness in the case of the typical applications.
Model of dynamic operation of stepper linear reluctance motor based on field approach
Authors: Mikołajewicz Jacek 
Published: July 2013

PurposeThe aim of this paper is to analyse the influence of various methods of controlling a stepper linear reluctance motor on the dynamic parameters of this motor.Design/methodology/approachConstruction, principle of working, and mathematical model of a four‐band stepper linear reluctance motor are shortly discussed. In order to elaborate an effective tool for motor performance analysis, a circuital approach was applied. To increase model accuracy, major parameters of the model (main self‐ and leakage inductances) were calculated on the basis of a 3D electromagnetic field distribution using Finite Element Method (FEM). The nonlinearity of the core was taken into account. Elaborated mathematical model was implemented in MatLab‐Simulink environment. Selected results of investigations are presented.FindingsThe elaborated mathematical model and the review of control methods are very useful for analysis of dynamic operation of stepper linear reluctance motors.Originality/valueThe paper provides a review of control methods of stepper linear reluctance motors.
Impact of windings switching on torque‐speed curves of PM BLDC motor
Authors: Krykowski Krzysztof , Hetmańczyk Janusz , Makieła Dawid 
Published: July 2013

PurposeWhen phase windings of brushless DC motor are switched, additional voltage drops across inductances of main circuit appear. These drops lead to, among other effects, increase of torque‐speed curve slope. The discussed research has been aimed at working out a simple and precise method of identifying torque‐speed characteristic of PM BLDC motor. The elaborated method takes into account the influence of windings switching and motor inductances on motor torque‐speed characteristic. In order to assess the results, extensive test simulations of models implemented in Matlab/Simulink software have been run. Results of analysis and test simulations have been compared with lab test results of two real PM BLDC motors.Design/methodology/approachAnalytical calculations take into consideration phenomena occurring during windings switch‐overs and impact of inductance on emerging voltage and rotational speed drops. It has been pointed out that on account of main circuit inductance, the average value of source current is less than average value of equivalent current generating electromagnetic torque. For analysis sake it has been assumed when windings are being switched‐over the current is kept constant; the motor parameters have also been assumed to be constant.FindingsA novel and accurate method of determining torque‐speed characteristics of PM BLDC motor has been worked out. This method has been investigated with the help of motor computer models implemented in Matlab/Simulink software and the obtained results have been subsequently compared with results of laboratory tests of two commercially available PM BLDC motors.Research limitations/implicationsThe object of the research was brushless DC motor with permanent magnet excitation. The impact of windings switch‐overs on torque‐speed curves of the motor has been analysed. Analytical method which makes it possible to determine torque‐speed curve of this motor very easily has been elaborated. Computer model of PM BLDC motor for Matlab/Simulink software has also been worked out. Extensive simulations helping to verify the proposed method have been run. Results of analysis and simulation tests have been verified by means of laboratory tests of two commercially available PM BLDC motors.Practical implicationsPM BLDC motors are used more and more widely. The new method of determining PM BLDC motors torque‐speed curves will facilitate analysis and design of drive systems utilizing these motors and will also speed up calculations.Originality/valueThe presented method of determining torque‐speed curves of PM BLDC motor is novel and much more precise than methods commonly used nowadays. Recognized methods usually neglect impact of inductance on motor properties.
Evaluating performances of electric machines supplied by the sinusoidal and pulse width modulated voltages
Authors: Štumberger Gorazd , Štumberger Bojan , Stojan David , Plantić Željko , Deželak Klemen , Čemažar Matjaž , Dolinar Drago 
Published: July 2013

PurposeMany authors reported the decrease of performances when electric machines and electromagnetic devices were supplied by pulse width modulated (PWM) voltages. However, these statements are rarely supported by measurements performed under fair conditions. The aim of this paper is to compare the performances of a single‐phase transformer and a three‐phase permanent magnet synchronous motor (PMSM) supplied by sinusoidal and PWM voltages and to find a way to evaluate the decrease of performances when PWM voltages are applied.Design/methodology/approachIn order to perform a fair comparison between performances of the tested objects supplied by sinusoidal and PWM voltages, an experimental system was built. It contains a single‐phase and a three‐phase linear rectifier for supply with sinusoidal voltages and an H‐bridge inverter and a three‐phase inverter for supply with PWM voltages. The tests and measurements were performed on a single‐phase transformer and three‐phase PMSM, where different constant loads and different modulation frequencies were used. The test conditions were identical for the supply by sinusoidal and PWM voltages. The measured data, used for the evaluation of performances, were the input and output power and the time behaviours of currents and voltages together with their THDs.FindingsThe results presented in the paper clearly show that the efficiency of the singe‐phase transformer and three‐phase PMSM decreases with the increasing level of voltage THD. To properly determine the THD of PWM voltage, the sampling frequencies above 1 MHz and special equipment are normally required. However, if the modulation frequency is not too high, also the current THD, which can be easily determined, can be used to evaluate the decrease of efficiency in the case of supply by PWM voltages.Originality/valueThe results presented in the paper clearly show that the efficiency of the singe‐phase transformer and three‐phase PMSM decreases with the increasing level of voltage THD.
Sizing of active power filters using some optimization strategies
Authors: Grabowski Dariusz , Maciążek Marcin , Pasko Marian 
Published: July 2013

PurposeThe change in the way of active power filters (APF) location can lead to overall cost reduction due to less number or less power of APFs required. The goal of this paper was to minimize the APF currents what is equivalent to solution with less apparent power of installed devices. The next step consists in development of new methods of APF optimal location.Design/methodology/approachSome scripts integrating optimization and harmonic analysis methods in Matlab and PCFLO software environments have been developed in order to achieve the goal.FindingsSolution to the minimization problem determines the current spectrum of an APF connected to a selected system bus in accordance with some optimization strategies which among others enable minimization of THDV coefficients.Research limitations/implicationsThe APF control algorithm defined in the frequency domain and based on given current spectrum could lead to some problems with synchronization between APF instantaneous current and compensated current waveforms.Originality/valueThere are many papers on APFs but usually systems in which an APF is connected near a nonlinear load are analyzed. Some attempts to solve the more complex problems of synchronized multipoint compensation have been already made but there is still no generally accepted and commonly used solution.
Improved iron loss calculation for non‐centered minor loops
Authors: Fratila Mircea , Benabou Abdelkader , Tounzi Abdelmonaïm , Dessoude Maxime 
Published: July 2013

PurposePulse width modulated (PWM) inverters are widely used to feed induction motors for variable speed applications. The use of PWM power supplies induces additional magnetic losses in the magnetic circuit of the electrical machine. The aim of this paper is to present a novel analytical approach to account for these losses.Design/methodology/approachThe methodology proposed here consists in identifying the analytical method with a static Preisach hysteresis model. The Preisach model was validated by comparing it with measurements obtained from an Epstein frame. Then, the results obtained with this approach were compared with a basic analytical method that is widely used.FindingsThe authors' model provides a fast way for estimating the minor loop iron losses introduced by static convertors. They compared the proposed model with another analytical model (J. Lavers model) for different wave forms. One can observe that the J. Lavers model overestimates the iron losses introduced by the non‐centred minor loops.Originality/valueIn this paper, an improved analytical model is presented which estimates the non‐centred minor loop iron losses. In order to do a precise estimation of the iron loss introduced by the minor loops, the authors' model takes into account the position and the size of the minor loop. The proposed model is identified from a static Preisach model.
Hysteresis curves of a resistance spot welding transformer
Authors: Petrun Martin , Chwastek Krzysztof , Dolinar Drago 
Published: July 2013

PurposeThe aim of the paper is to provide a simple and reliable hysteresis model for prediction of magnetization curves of a resistance spot welding transformer (RSWT) core, operating in a wide range of flux densities and excitation frequencies.Design/methodology/approachThe hysteresis model considered in the paper is the T(x) description advanced by J. Takács. Three options to extend the model to the dynamic magnetization conditions are considered. The excitation conditions differ from those prescribed by international standards.FindingsThe quasi‐static Takács model combined with a fractional viscosity equation similar to that proposed by S.E. Zirka outperforms other considered options. The effect of eddy currents may be considered as a disturbance factor to the frequency‐independent quasi‐static hysteresis loop.Research limitations/implicationsThe combined approach yields in most cases a satisfactory agreement between theory and experiment. For highest frequency considered in the paper (1 kHz) excessive “heels” were observed in the modelled loops. This artifact may be reduced by the introduction of a more complicated relationship for the viscous term. Future work shall be devoted to this issue.Practical implicationsThe combined Takács‐Zirka model is a useful tool for prediction of magnetization curves of a RSWT core in a wide range of flux densities and excitation frequencies.Originality/valueThe usefulness of the Takács description has been verified in a practical application. The model is able to predict magnetization curves under non‐standard excitation conditions.
SMA actuators: theory, performance curves and design problems
Authors: Kluszczyński Krzysztof , Kciuk Marek 
Published: July 2013

PurposeThe main purpose of the paper is to develop model basing on the modified and properly‐adopted Fermi‐Dirac equation which combines proper accuracy with adequate simplicity as well as to show how steady state and transient curves resulting from this model can be applied for solving design task.Design/methodology/approachThe standard Fermi‐Dirac equation was modified and extended. Full performance cycle for the SMA actuator was characterized by double‐valued function describing the actuator activation and the actuator deactivation. All these functions and parameters can be easily determined by analysis of measurement data or with use of Hooke‐Jeeves optimization algorithm.FindingsSMA linear actuator can be used in mechatronic systems as a special non‐standard drive when ultra‐light mass and very simple mechanical construction of power feed system is required. The proposed steady‐state and transient performance curves as well as operation diagram constitute sufficient base for effective designing SMA drive systems.Research limitations/implicationsThe greatest disadvantage of a SMA actuator is long time of deactivation resulting from slow self‐cooling process. As far as efficiency is concerned as essential factor for choosing the most suitable linear actuator, there is no sense to take into account a linear SMA actuator because of its very low efficiency.Practical implicationsDesigner can use performance curve which determines proper length of SMA actuator and range of its motion. The proposed model can be implemented in SMA drive control unit for controlling position of the actuator.Originality/valueSimilarities between change of martensitic phase during transition process and probability P of electron energy level distribution described by the Fermi‐Dirac two‐variable equation were taken into account. Such an approach seems to express in the most suitable way the physical nature of m‐a transition. The authors decided to extend concept (proposed in Jayender et al.) and to adopt the Fermi‐Dirac equation for describing behaviour of a SMA linear actuator.
Identification of current flow depending on the mechanical deformation in a stranded cable
Authors: Zeroukhi Youcef , Napieralska Juszczak Ewa , Komeza Krzysztof , Morganti Fabrice , Vega Guillaume 
Published: July 2013

PurposeIn the majority of devices for measuring the resistance of wires or cables, the supplying voltage is applied via some clamping arrangement. Thus, current enters the bundle of conductors through the side surface of the outside wire. The purpose of this project was to establish the distance from the supplying point after which the current may be considered to be uniform and normal to the cable cross‐section.Design/methodology/approachWhen current passes from one wire to another, the crucial parameter is the resistance of the contact region. The paper presents a method by which this region can be identified and relevant resistance measured. A comprehensive simulation was conducted for different types of wires and cables to assess the influence of design parameters on the current distribution and uniformity.FindingsThe distance from the current entry point (the clamps) to the position where current density may be considered uniform has been established. This has facilitated estimating recommended positions of voltage taps with reference to current taps.Practical implicationsThe look‐up tables and graphs allow adjustments to the position of the taps and/or correction of the measured results.Originality/valueThe original contribution of this paper is in the way the contact region is identified where current passes from one wire to another. Original relationships have been proposed showing the relationship between contact resistance and the design parameters of the cable and mechanical stress.
Information needs analysis of the aerospace discipline
Authors: Du Weichun , Song Shuang 
Published: July 2013

PurposeThe purpose of this paper is to identify the core literature of aerospace studies and the databases necessary to ensure its coverage in a collection for aerospace scientists. The paper also aims to examine whether China has different needs from other countries.Design/methodology/approachA sequence of bibliometric analyses was used. Institutions and countries with high aerospace research productivity were identified from 4,290 papers published in “aerospace engineering” journals in Science Citation Index. Journal papers cited in these papers (14,618 extracted from 17,015 citations in all) were analyzed to discover the core source journals for aerospace research. The availability of the core journals in online databases determined necessary library provision for aerospace research.FindingsThe most productive aerospace research institutions are in China and the USA. Journals are the most important information resources. While 20 per cent of cited journals were discipline‐specific, 80 per cent were in related fields. Chinese researchers had similar resource needs to researchers from other countries. To provide for aerospace research, a library collection needs to include the databases of the field, and commercial and open access journals that cover aerospace engineering, related disciplines and the sciences in general.Originality/valueThe paper reveals the characteristics of the literature of the aerospace discipline for the first time. It identifies the core journals used by aerospace researchers and the bundle of online resources necessary to adequately provide for research in the field. The technique used can be applied to other disciplines.
Logistics alliance management capabilities: where are they?
Authors: Brekalo Lisa , Albers Sascha , Delfmann Werner 
Published: July 2013

Purpose
– Due to the continued high failure rate of logistics alliances, the purpose of this paper is to propose incorporating the widely neglected dynamic capabilities approach into the explanation of logistics alliance performance.

Design/methodology/approach
– The authors identify specific characteristics of logistics alliances that are used to argumentatively develop a framework of logistics alliance management capabilities.

Findings
– We propose an initial framework of logistics alliance management capabilities, based on the dynamic capabilities approach of strategic management, with the aim of improving logistics alliance success.

Research limitations/implications
– The presented framework offers a basis for a wider range of empirical studies. Qualitative researchers are encouraged to further specify and better understand the sub-processes that underlie logistics alliance management capabilities in different alliance settings. Quantitative studies could help to reliably assess the differences and performance implications of these capabilities.

Practical implications
– The authors
'
conceptualization supports managers in their relevant strategic and organizational attempts to enhance logistics alliance success.

Originality/value
– This paper contributes to the logistics literature by making a more general yet established construct accessible to logistics scholars and practitioners. The roots of the authors
'
logistics alliance management capabilities construct in dynamic capabilities provide a framework that is new and potentially more comprehensive than the collection of somewhat isolated alliance success factors that have hitherto been proposed in the logistics literature.
The impact of dependence and trust on supply chain integration
Authors: Zhang Min , Huo Baofeng 
Published: July 2013

Purpose
– The purpose of this paper is to investigate the joint influence of dependence and trust in supply chain relationships on supply chain integration (SCI) and financial performance.

Design/methodology/approach
– This study develops a dependence-trust-SCI-performance model and tests it using structural equation modeling based on empirical data collected from 617 manufacturers in China.

Findings
– The results show that trust with customers/suppliers significantly influences SCI. Although dependence on customers/suppliers has no direct effect on SCI, it improves SCI indirectly through trust with customers/suppliers. Both supplier integration and customer integration significantly improve financial performance.

Practical implications
– This study suggests that manufacturers should manage dependence and trust in supply chain relationships simultaneously to enable SCI. When there is high-level dependence on customers/suppliers, manufacturers should invest resources to develop trust with those customers/suppliers. Moreover, to achieve a better financial performance, manufacturers should integrate with both customers and suppliers.

Originality/value
– This study contributes to the literature by providing empirical evidence regarding the direct effect of trust on SCI, and the indirect influence of dependence on SCI through trust. This extends extant knowledge regarding the joint impact of dependence and trust on SCI. Hence, both researchers and practitioners should pay attention to interdependence among different relationship management practices. Moreover, this study also empirically supports the argument that SCI improves firms
'
financial performance.