bluuebunny/crossref_metadata_2025_split huggingface dataset:
A simplified approach to permanent magnet and reluctance motor characteristics determination by finite‐element methods
Authors: Reichert Konrad 
Published: July 2006

PurposeTo provide a new method for the determination of motor characteristics by means of FE‐methods suitable for multi‐variable design processes.Design/methodology/approachThe process is based on two‐dimensional, steady state and frequency domain FE‐analysis including a stepwise movement of the rotor. The process consists of the following steps: generation of an appropriate FE‐model with specific mesh generation; input of the machines parameters and the parameters of the simulation process; no load simulation: cogging torque T, no load fluxes ψmo and voltages uo and the phase angles of the windings currents; load simulation with given currents: average and the pulsating torque T, fluxes ψl(α), voltages U, two‐axis model parameters ψm, Ld and Lq; determination of operating characteristics: torque T, voltage U, current I, power P, angles β and δ cos ϕ, as functions of speed n. Based on machine parameters from step 3 and 4 determination of losses in the magnets by means of a frequency domain model and the fluxes in the magnet from steps 3 and 4.FindingsSpecial attention has to be given to the mesh design. The mesh configuration should be kept constant during the movement. Motor parameters are determined for one operating point. The process is very fast and accurate enough ( < errors) for design purposes.Practical implicationsIt is shown how FE‐methods can be used in motor design, avoiding time‐consuming transient simulations.Originality/valueIt is a new and very efficient FE‐process for motor design.
Simulation and experimentation of a single‐phase claw‐pole motor
Authors: Reinap A. , Alaküla M. , Nord G. , Hultman L.O. 
Published: July 2006

PurposeThe purpose of the paper is to evaluate theoretically and experimentally the static and dynamic characteristics of a single‐phase claw‐pole motor using soft magnetic composite (SMC) for the stator core.Design/methodology/approachOn the basis of the static characteristics, which are measured and obtained from a series of 3D FE magnetostatic solutions, the dynamic characteristics are simulated according to a proposed control strategy. The same strategy is tested in dSpace control environment. Apart from the evaluation of the prototype SMC motor, some study has been made in order to improve the existing motor design.FindingsThe static characteristics of the single‐phase claw‐pole motor have been modelled in 3D FE magnetostatic solver, where the rotor position and stator current have been changed. The characteristics compare well with the measurements, while the discrepancy with the cogging torque waveform needs further analyses and experiments to explain the real magnetization pattern of the plastic bounded ferrite magnet‐ring and the influence of magnetic hysteresis. The 3D FE magnetostatic optimization routine shows the maximum quantities for magnetic coupling and static core loss. Furthermore it is used to obtain the improved pole distribution so that the resting position of the unexcited motor co‐aligns at the position of the maximum electromagnetical torque. This is achieved by changing the angular width of claw‐poles. The specific output of the maximum coupling torque from the single‐phase claw‐pole motor can be increased from the recent 0.1 to 0.6 Nm/kg at a temperature rise of 60°. The simulations of dynamical characteristics show a good correlation with the experiments where the same control system in Simulink is applied to the prototype via dSpace. It is practically easier to implement a simple control strategy for the direct current controlled voltage source inverter. A more advantageous control system needs to be applied for the sampled current controller.Research limitations/implicationsThe influence of the magnetization of a multi‐pole magnet ring is not considered while computing the static characteristics in 3D FE magnetostatic solver.Practical implicationsThe evaluation of the realistic magnetization pattern in the magnet aggravates the proper theoretical evaluation of static characteristics.Originality/valueThe design of a small size powder core motor is faced with the complexity of evaluating properly the static characteristics, while the magnetization pattern is not exactly known. The broad search here is for an efficient tool to visualize the output of the 3D FE optimization for an improved design.
Stator optimization of six‐phase claw‐pole alternators using asymmetric winding arrangements
Authors: Schulte S. , Kaehler C. , Schlensok C. , Henneberger G. 
Published: July 2006

PurposeTo present a new approach for improvement and optimization of synchronous claw‐pole alternators without changing the general machine design.Design/methodology/approachVarious changes on the magnetically relevant parts of the machine design have been discussed formerly to achieve improved electromagnetic and acoustic behavior. The electrical part of the machine is considered in this paper, varying the stator winding arrangement to achieve optimized behavior.FindingsProvides information about motivation and the methodology of the optimization process. Presents the entire analysis, covering idea, technical and computational implementation as well as verification.Research limitations/implicationsIt describes a method based on the utilization of specific, partly self‐generated software, which perhaps limits its usefulness if mentioned tools are unavailable. However, the presented basic method is to be used generally.Originality/valueThis paper presents a promising approach to further optimize the design of synchronous claw‐pole alternators without major changes in the machine design.
Sliding‐surface interface conditions for 3D machine models discretised by the finite integration technique
Authors: Ion Mariana , De Gersem Herbert , Wilke Markus , Weiland Thomas 
Published: July 2006

PurposeTo propose trigonometric interpolation in combination with the sliding‐surface technique for modeling rotation in electrical machine models discretised by the finite integration technique (FIT).Design/methodology/approachLocked‐step, linear and trigonometric interpolation techniques are developed for coupling the stator and rotor model parts of an electrical machine model.FindingsLinear and trigonometric interpolation should be preferred over the locked‐step approach. Three‐machine models with sliding‐surface coupling discretised by the FIT result in efficient and reliable models.Originality/valueThe introduction of sliding‐surface techniques in the FIT, the trigonometric interpolation used in combination, the application of the FIT for simulating electrical machines.
3D nonlinear transient finite element analysis of eddy currents in the stator clamping system of large hydro generators
Authors: Schmidt Erich , Traxler‐Samek Georg , Schwery Alexander 
Published: July 2006

PurposeAn accurate calculation of eddy current losses in the stator clamping parts of large hydro generators is a matter of particular interest with the initial design and the design optimization because they can reach high values and produce local thermal hot‐spots due to the non‐linear magnetic behaviour of the clamping plate.Design/methodology/approachWith a fully 3D approach of the generator pole pitch, both time‐harmonic and non‐linear transient finite element analyses are carried out for the eddy currents using a magnetic vector potential formulation.FindingsWith the introduction of a novel modelling strategy for the non‐linear clamping plate, the total eddy current losses evaluated from both analysis methods show a good agreement. Nevertheless, the time‐harmonic solution in comparison with the non‐linear transient solution yields different local eddy current distributions in particular with the clamping plate.Research limitations/implicationsThe presented analyses use only the fundamental harmonic in the end region field. Further research will need to be carried out for the influence of the higher harmonics in the end region field and again the comparison of both analysis methods.Practical implicationsWith the intention of including the numerical analyses with design review and design optimization of the generators, the results obtained from both analysis methods are compared regarding the total eddy current losses as well as their local distributions.Originality/valueWith a fully 3D approach of the generator pole pitch, second order pentahedral and hexahedral edge elements are introduced with both time‐harmonic and non‐linear transient eddy current finite element analyses.
Inclusion of inter‐bar currents in multi‐slice FE modelling of induction motors – influence of inter‐bar resistance and skew discretisation
Authors: Gyselinck J. , López‐Fernández X.M. 
Published: July 2006

PurposeTo study the inclusion of inter‐bar (IB) currents in a multi‐slice finite element (FE) model of induction motors and in particular the effect of the associated skew discretisation. To validate the model experimentally.Design/methodology/approachBoth a classical uniform distribution and a gauss distribution of the slices and the lumped IB resistances are considered. Measurements on a 3 kW induction motor allows one to estimate its IB resistance and to validate the FE model.FindingsA gauss distribution of the slices allows one to use fewer slices and thus reduces the computational cost. The simulation results show that, at full load, skew changes the different loss components significantly, while the IB currents have a minor effect.Research limitations/implicationsThe direct measurement of the IB resistance is by no means trivial. In the frame of this paper, it was indirectly determined, namely by means of a short‐circuit test.Originality/valueThe gauss distribution of the slices and the IB resistance; the systematic study of the skew discretisation; the experimental determination of the IB resistance.
Eddy current heating in large salient pole generators
Authors: Riley C.P. , Michaelides A.M. 
Published: July 2006

PurposeThe purpose of the paper is to investigate pole face heating in large, salient pole generators and establish a modelling procedure for accurate rotor pole heat loss computation using finite element analysis.Design/methodology/approachFinite element‐based simulations of the dynamic electromagnetic problem in an idealized 60 Hz, six‐pole, three‐phase generator were carried out, including coupling to three‐dimensional finite element thermal analysis.FindingsThe effect of trailing pole face heating was effectively demonstrated. Accurate estimates of the ventilation and convective cooling were shown to be particularly important.Research limitations/implicationsAccurate heat transfer values could only be obtained using a very sophisticated model in a computational fluid dynamics analysis software package. The complexity of the stator end winding alone makes this a daunting challenge, without the inclusion of the rotation effects and stator cooling ducts. At this stage, it was deemed more useful to use the thermal analysis to observe trends.Practical implicationsThree‐dimensional effects are significant and require modelling. However, obtaining steady state behaviour using a 3D analysis is probably not viable yet. The synchronous operating conditions were obtained from a two‐dimensional analysis and used as the initial conditions for a full 3D analysis.Originality/valueThe paper has helped to enhance the understanding of pole face heat loss in large salient pole synchronous generators, fully examining the mechanisms causing the heating. A complete procedure to achieve this task in a realistic time frame using sophisticated finite element analysis tools has been proposed.
Representation of permanent magnet brushless machine by means of orthogonal functions
Authors: Witczak Paweł , Wawrzyniak Beata , Napieralska‐Juszczak Ewa 
Published: July 2006

PurposeTo develop a fast and accurate method of calculation of permanent magnet machines.Design/methodology/approachPresently two ways exist of modeling of synchronous machines – the classic one, when the concept of inductances Ldand Lqis used and the numerical, time‐stepping approach. The first cannot account for precisely the saturation effects, while the second one is highly time consuming. Proposed algorithm replaces inductances by the distributions of flux densities, which were used for their definition, obtained from finite element solutions. Mathematically, the analysis is converted from the space of trigonometric functions to the more general space of periodic functions.FindingsThe compact algorithm of analysis has been found, making it possible to extend its application to other types of machines.Research limitations/implicationsValidation of the proposed method was done only by cross‐checking with integral parameters coming from finite element solution.Practical implicationsA potentially useful idea of representation of an electric machine for control purposes.Originality/valueThe paper presents original concept of the new approach for the representation of electric machines. Parts of that methodology were discussed among specialists during two international conferences and received positive views.
Accuracy improvement in nonlinear magnetostatic field computations with integral equation methods and indirect total scalar potential formulations
Authors: Hafla Wolfgang , Buchau André , Rucker Wolfgang M. 
Published: July 2006

PurposeThe paper seeks to solve nonlinear magnetostatic field problems with the integral equation method and different indirect formulations.Design/methodology/approachTo avoid large cancellation errors in cases where the demagnetizing field is high a difference field concept is used. This requires the computation of sources of the scalar potential of the excitation field.FindingsA new formulation to compute these sources is presented. The improved computational accuracy is demonstrated with numerical examples.Originality/valueThe paper develops a novel formulation for the computation of sources of scalar excitation potential.
Magneto‐electric network models in electromagnetism
Authors: Demenko Andrzej , Sykulski Jan 
Published: July 2006

PurposeThe aim of this paper is to develop network models of an electromagnetic field containing both eddy and displacement currents. The proposed network models provide good physical insight, help understanding of complicated electromagnetic phenomena and aid explanation of methods of analysis of electromagnetic systems.Design/methodology/approachThe models consist of magnetic and electric networks coupled via sources. The analogy between the finite element method and the loop and nodal formulations of electric circuits is emphasised. The models include networks containing branches associated with element edges (edge networks) or facets (facet networks).FindingsMethods of determining mmf sources of magnetic networks from loop and branch currents in electric circuits, as well as emf sources in electric networks on the basis of the rate of change of loop and branch fluxes in electric networks, have been carefully considered. The models are general and allow creation of networks of electromagnetic systems containing non‐homogenous materials and multiply‐connected conducting regions.Originality/valueThe presented analogies between the finite element formulation and the equivalent network models not only facilitate understanding of the methods of field analysis but also help to formulate efficient computational algorithms.
Reconstruction of crack profile using fuzzy logic
Authors: Sikora Ryszard , Baniukiewicz Piotr 
Published: July 2006

PurposeThe aim of the paper is to develop an algorithm based on fuzzy logic (FL) systems for reconstructing cracks shapes, which will be faster and simpler to learn than neural networks, especially in case of large training set.Design/methodology/approachThe inverse model in defectoscopy can be considered as reverse model of the whole measurement process (crack‐sensor‐output). The most important disadvantage of the inverse neural models with dynamic networks is that the performance of training is disappointing due to large training set and many inputs of such networks. The paper proposes the FL as the substitute of neural network. The typical ANFIS networks are sufficient only for simulating systems with small number of inputs. For this reason the paper developed the learning algorithm that produces relatively small number of rules and it can be used in case of systems with hundred of inputs and thousands of training pairs.FindingsThis paper provides details about algorithm for reconstructing cracks profiles that produces relatively small number of rules of the fuzzy system. The basis rule of inverse model with moving window for one‐ and multi‐frequency method is described. The results of profile identification in 2D and 3D space for real and simulated data are presented as well.Originality/valueGenerally, the algorithm proposed in this paper can be widely used for simulating multi‐input systems, which are described by a large training set.
Computation of general nonstationary 2D eddy currents in linear moving arrangements using integrodifferential approach
Authors: Karban Pavel , Doležel Ivo , Šolín Pavel 
Published: July 2006

PurposeMost eddy current problems are solved using numerical schemes based on the differential approach. Nevertheless, there exist several classes of tasks where use of this approach may be complicated (problems characterized by geometrical incommensurability of individual subdomains, motion, etc.). In such cases, application of the integrodifferential approach may be an advantage. The paper seeks to present the theoretical background of the method.Design/methodology/approachThe mathematical model consists of a system of integrodifferential equations for current densities in electrically conductive domains.FindingsThe methodology is illustrated on an example. All computations are realized by a code developed and written by the authors.Originality/valueThe presented algorithm based on the integrodifferential approach makes it possible to solve problems that are only hardly solvable by classical differential methods.
Absorbing boundary conditions for compact modeling of on‐chip passive structures
Authors: Ioan Daniel , Ciuprina Gabriela , Radulescu Marius 
Published: July 2006

PurposeThe paper has the purpose of proposing a new open boundary condition to be used in conjunction with the finite integration technique (FIT) for the modelling of passive on‐chip components.Design/methodology/approachThis boundary condition is ensured by using a virtual layer that surrounds the computational domain.FindingsThe paper proves which are the optimal material properties of the equivalent layer of open boundary.Practical implicationsWhen modelling passive on‐chip components with FIT, the method proposed is more efficient than the strategic dual image technique.Originality/valueThe paper shows the advantage of this approach – that the analysis algorithm remains unchanged, while saving the field‐circuit compatibility properties, such as current conservation.
Wide frequency band analysis of an antenna by finite elements
Authors: Choua Y. , Le Bihan Y. , Pichon L. 
Published: July 2006

PurposeThe aim of this paper is to calculate the impedance of a loop antenna, etched on a dielectric substrate, over a wide frequency band using finite element method (FEM).Design/methodology/approachThe electromagnetic analysis of the global structure is performed with a full wave finite element formulation. In this work, two methods for the calculation of the impedance of the antenna are presented: receiving and transmitting mode. The results obtained are compared with boundary element method (BEM).FindingsThe paper finds that from the FEM analysis an equivalent circuit of a rectenna was obtained over a wide frequency band. A good agreement was obtained with a BEM approach in the case of an air‐like substrate. A dielectric substrate was considered. Such a configuration is more difficult to deal with BEM and makes the FEM attractive.Practical implicationsThe equivalent circuit allows a global circuit simulation of the whole rectenna (antenna, rectifying diodes and load). This simulation can be achieved using spice simulator for example.Originality/valueThis paper shows the potentiality of the FEM to simulate an antenna over a broad band frequency. Two methods for the calculation of the impedance of the antenna are presented. It is addressed to R&D designers in the microwave area.
Application of Spice simulator in the evaluation of crosstalk computational models
Authors: Tosin André , Gerlach Dietz Willian , França Sartori Carlos Antonio , Roberto Cardoso José 
Published: July 2006

PurposeThis paper aims to present an evaluation of the crosstalk models developed for a shareware version of Spice.Design/methodology/approachThe transmission line model is compared with π lumped circuit models by varying the number of cells. The influence of losses is also introduced, and some constraints regarding the models are examined, showing the suitability of the new Spice libraries developed by the authors. In order to validate the theoretical results some experiments were carried out.FindingsThe paper finds that Spice is a powerful engineering tool for students and technicians involved in EMC analyses.Originality/valueThe main aspects concerning the accuracy and integrity of the experimental data are emphasized and discussed in this paper.
Rigorous ADI‐FDTD analysis of left‐handed metamaterials in optimally‐designed EMC applications
Authors: Kantartzis Nikolaos V. , Tsiboukis Theodoros D. 
Published: July 2006

PurposeThe paper seeks to investigate the precise time‐domain modelling and broadband performance optimisation of 3D EMC structures formed by composite left‐handed metamaterials.Design/methodology/approachA frequency‐dependent alternating‐direction implicit finite‐difference time‐domain method is introduced. Developing a class of multi‐directional curvilinear schemes for double‐negative media, the unconditionally stable algorithm forms robust lattice tessellations and provides advanced models complicated media interfaces. Moreover, the erroneous refractions at the metamaterial boundaries are systematically analysed through dynamic stencil configurations and powerful perfectly matched layer absorbers.FindingsThe paper finds that the proposed technique leads to convergent discretisations that resolve all propagation bandwidths and enhances the design of promising periodical devices loaded by substrates of thin wires and split‐ring resonators. Furthermore, its versatile character subdues dispersion deficiencies far beyond the usual stability criteria. Numerical validation, addressing various up‐to‐date EMC devices like coupled antennas, waveguides, high‐pass filters and absorber linings in test facilities, confirms the merits of the algorithm.Originality/valueThe novel methodology offers an advanced nodal control process which drastically suppresses the serious dispersion errors of existing approaches as time‐step exceeds the Courant limit. The resulting grids can support coarse resolutions, while the general curvilinear framework, along with the ADI rationale, allows the accurate approximation of demanding permittivity and permeability constitutive profiles. Hence, high accuracy and confined computational overhead are achieved without the need of laborious assumptions.