Applied sciences

Archives of Electrical Engineering

Content

Archives of Electrical Engineering | 2011 | vol. 60 | No 1 March |

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Abstract

A method for modeling of the dynamics characteristics for a 5-phase permanent magnet tubular linear motor (PMTLM) is presented. Its electromagnetic nonlinear field analysis with finite element method (FEM) has been coupled with the circuit model. The calculation model includes the equations for electrical circuits and mechanical quantities as well. They have been obtained using Lagrange's method. The calculated and measured waves of the mover position have been compared for several values of the excitation current. This comparison yields a good agreement. Presented calculation model is very useful in designing and optimization of the PMTLM and in the calculation of the parameters for the control algorithms intended for such a type of actuators.
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Authors and Affiliations

Bronisław Tomczuk
Andrzej Waindok
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Abstract

This research presents a method of modeling and numerical simulation of a reluctance stepper motor using reduced finite-element time-stepping technique. In presented model, the circuit equations are reduced to non-stationary differential equations, i.e. the inductance mapping technique is used to find relationship between coil inductance and rotor position. A strongly coupled field-circuit model of the stepper motor is presented. In analyzed model the magnetostatic field partial differential equations are coupled with rotor motion equation and solved simultaneously in each iterative step. The nonlinearity problem is solved using Newton-Raphson method with spline approximation of the B-H curve.
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Authors and Affiliations

Jakub Bernat
Jakub Kołota
Sławomir Stępień
Grzegorz Szymański
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Abstract

The paper presents a method of computing electrical and mechanical variables of BLDC motors. It takes into account electrical, magnetic and mechanical phenomena in the power supply-converter-BLDC motor-load machine system. The solution to the problem is the so-called circuit-field method. The results determined with the use of time stepping finite element method were used as the parameters of equations of the developed mathematical model. Losses in the motor, losses in transistors and diodes of the converter as well as the actual back EMF waveforms, variable moment of inertia and variable load torque are accounted for. The designed laboratory stand and the test results are presented in the paper. The experimental verification shows the correctness of the developed method, algorithm and program. The developed computational method is universal with respect to different electromechanical systems with cylindrical BLDC motors. It can be applied to electromechanical systems with BLDC motors operating at constant but also variable load torque and moment of inertia.
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Authors and Affiliations

Marek Ciurys
Ignacy Dudzikowski
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Abstract

This paper presents a method for estimation of core losses in banks of single phase power transformers that are subjected to an injected DC current such as geomagnetically induced currents (GIC). The main procedure of the core loss calculation is to obtain a magnetic flux density waveform in both time and location by using a novel algorithm based on 3D FEM inside the core and then to calculate the loss distribution based on loss separation theory. Also, a simple and effective method is proposed for estimation of losses of asymmetric minor loops by using combination of symmetric loops. The effect of DC biasing on core losses in single phase power transformers is investigated and the sensitivity of core type and material is evaluated. the results shows that DC current biasing could increase core losses up to 40 percent or even more.
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Authors and Affiliations

Seyed Mousavi
Göran Engdahl
Edris Agheb
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Abstract

An extension of the modified Jiles-Atherton description to include the effect of anisotropy is presented. Anisotropy is related to the value of the angular momentum quantum number J, which affects the form of the Brillouin function used to describe the anhysteretic magnetization. Moreover the shape of magnetization dependent R(m) function is influenced by the choice of the J value.
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Authors and Affiliations

Krzysztof Chwastek
Jan Szczygłowski
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Abstract

The paper presents a formula useful for prediction of loss density in soft magnetic materials, which takes into account multi-scale energy dissipation. A universal phenomenological P(Bm, f) relationship is used for loss prediction in chosen soft magnetic materials. A bootstrap method is used to generate additional data points, what makes it possible to increase the prediction accuracy. A substantial accuracy improvement for estimated model parameters is obtained in the case, when additional data points are taken into account. The proposed description could be useful both for device designers and researchers involved in computational electromagnetism.
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Authors and Affiliations

Jan Szczygłowski
Paweł Kopciuszewski
Krzysztof Chwastek
Mariusz Najgebauer
Wiesław Wilczyński
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Abstract

The purpose of that paper is to develop of unified equations of electromechanical energy converters accounting for the magnetic non-linearity of the main magnetic circuit of a converter. The concept of applying higher order forms of winding currents for the description of the co-energy function is introduced in order to derive the structure of converter equations via mathematical analysis. Also, another concept of equivalent magnetizing currents is applied to determine the higher order forms for selected converters designs. The structure of circuital equations for converters with multiple windings has been unified by means of the introduction of matrices of dynamic and nonlinear inductances following the higher order forms of the co-energy function.
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Authors and Affiliations

Tadeusz Sobczyk
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Abstract

The paper investigates a significant influence of transients on steady states in a matrix converter with the one-periodic control strategy. Proposed controller can be used as an interconnection device within a power system for a power flow control. However, the presence of inductances in external systems has the significant influence on steady state of a matrix converter operation. The special current injection method has been developed to ensure a proper operation of a matrix converter. Presented analysis of steady states is carried out in a frequency domain using the harmonic balance method. Obtained numerical results, which are confirmed by a time domain analysis, prove the effectiveness of the proposed method.
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Authors and Affiliations

Dariusz Borkowski
Tadeusz Sobczyk
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Abstract

This paper investigates the possibility of exciting high quality trapped resonant modes on frequency selective surfaces consisting of identical sub-wavelength metallic inclusions (symmetrically split rings) with no structural asymmetry but exhibitting electrical asymmetry. The electrical symmetry is broken by using different dielectric substrates. The existence of such anti-symmetric trapped mode on geometrical symmetric structure is demonstrated through numerical simulation. Numerical results suggest that the high quality factor observed for these resonant modes is achieved via weak coupling between the "trapped modes" and free space which enables the excitation of these modes.
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Authors and Affiliations

Mihai Rotaru
Jan Sykulski
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Abstract

A simplified isoperibol calorimetry method for measuring specific heat in solids is described. Taking advantage of the classical Nernst dependency the specific heat is calculated from time-domain temperature curves registered for a sample forced heating and natural cooling phase. In order to improve accuracy of the measurements a correction factor, taking into account the heat transferred to the surrounding, is introduced along with a procedure of statistical elimination of unavoidable measurement deviations. The method is implemented in a simple and straightforward measuring system involving no vacuum calorimeter. The method is applicable for quick and routine specific heat measurements performed on small solid dielectric or metallic specimens at near-room temperature. Test results of various materials used commonly in electrical engineering are demonstrated and discussed as well as comparison to drop calorimetry and differential scanning calorimetry reference measurements is included. The overall repeatability of the test method and the simplified apparatus is estimated as not worse than 2.6%.
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Authors and Affiliations

Leszek Moroń
Paweł Żyłka

Instructions for authors

ARCHIVES OF ELECTRICAL ENGINEERING (AEE) (previously Archiwum Elektrotechniki), quarterly journal of the Polish Academy of Sciences is OpenAccess, publishing original scientific articles and short communiques from all branches of Electrical Power Engineering exclusively in English. The main fields of interest are related to the theory & engineering of the components of an electrical power system: switching devices, arresters, reactors, conductors, etc. together with basic questions of their insulation, ampacity, switching capability etc.; electrical machines and transformers; modelling & calculation of circuits; electrical & magnetic fields problems; electromagnetic compatibility; control problems; power electronics; electrical power engineering; nondestructive testing & nondestructive evaluation.

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