Wyniki 1-3 spośród 3 dla zapytania: authorDesc:"Ivanna VASYLCHYSHYN"

Development of Macromodels using the Evolutionary Algorithms of Optimization

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A new technique for mathematical model development based on evolutionary algorithms and optimization approach to macromodels construction has been proposed in this paper. Examples of models constructed with the use of the proposed algorithm have been presented. A comparison of new models and models created using sole optimization approach has been done. Streszczenie. Praca przedstawia nową metodę budowania makromodeli przy użyciu algorytmów ewolucyjnych optymalizacji. Proponowane podejście zostało zilustrowane przykładami konkretnych modeli, a wyniki porównane z tymi uzyskanymi przy zastosowaniu tradycyjnych deterministycznych metod optymalizacji (Budowa makromodeli z użyciem algorytmów ewolucyjnych). Keywords - mathematical model, macromodel, optimization, evolutionary algorithms Słowa kluczowe: modelowanie matematyczne, optymalizacja, algorytmy ewolucyjne Introduction At present time there is a considerable progress in construction of macromodels of electrotechnical components designed for the transients’ analysis. The permanent growth of macromodel complexity leads to the necessity of the macromodel construction process automation in case it is possible. A promising approach in this direction is the usage of optimization. According to this technique the values of macromodel coefficients are found by the minimization of some goal function Q(λ). This function represents the deviation of the object behavior calculated using the model being constructed and experimental data as a function of model coefficients. By finding the point where the mentioned function reaches its minimum we will find an optimal set of the model coefficients within a selected mathematical form of the model representation. Described approach can be used for the construction of macromodels in any mathematical form, which is represented by a limited set of coefficients. Also it does not impose any restrictions on required input information except [...]

Determining of complex magnetic permeability of the ferromagnetic material by complex impedance of inductance coil with ferromagnetic core DOI:10.12915/pe.2014.04.053

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The article presents a methodology of determining of complex magnetic permeability of ferromagnetic material by the results of measuring complex impedance of inductance coil with ferromagnetic core. The complex impedance of the inductance coil was measured with immittance meter E7-25. Streszczenie: W pracy przedstawiono metodę wyznaczania zespolonej przenikalności magnetycznej materiału przez pomiar zespolonej indukcyjności cewki z rdzeniem wykonanym z badanego materiału. Impedancja zespolona została zmierzona przy pomocy miernika immitancji E7- 25, opisanego w pracy. (Wyznaczanie zespolonej przenikalności magnetycznej przez pomiar zespolonej indukcyjności) Keywords: Inductance coil with ferromagnetic core, complex impedance, magnetic permeability. Słowa kluczowe: indukcyjność, cewka, rdzeń ferromagnetyczny, impedancja zespolona, przenikalność magnetyczna. doi:10.12915/pe.2014.04.53 Introduction A laying-on parametric eddy current probe (inductance coil with ferromagnetic core) with U-type core is traditionally used in the process of eddy current defectoscopy for ferromagnetic material with anisotropy properties. This eddy current probe is a coil with ferromagnetic U-type core with winding of number turns w thereon. To determine active resistance and reactance introduced by the tested area of ferromagnetic material it is necessary to know complex magnetic permeability. Earlier we devoted a number of works to research of interrelation of eddy current probe with ferromagnetic specimen [1]-[3]. Mathematical model of physical processes which occurs in the ferromagnetic core of the coil The objective of the research is development of methods for determining complex magnetic permeability of ferromagnetic material by the results of measuring of active resistance and reactance of inductance coil with toroidal core (shown in Fig.1). Fig. 1. A coil with toroidal ferromagnetic core The flux induced in the ferromagnetic core of inductance[...]

Evaluation of Discrete Modeling Efficiency of Asynchronous Electric Machines

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In the paper the problem of effective mathematical macromodels in the form of state variables intended for asynchronous motor transient analysis is considered. Their comparison with traditional mathematical models of asynchronous motors including models built into MATLAB/Simulink software was carried out and analysis of their efficiency was conducted. Streszczenie. W artykule przedstawiono matematyczne makromodele silników asynchronicznych w postaci równań stanu przeznaczonych do analizy czasowej. Porównano je z tradycyjnymi modelami matematycznymi, w tym modelami wbudowanymi w MATLAB/Simulink (Ocena efektywności dyskretnych modeli maszyn asynchronicznych) Keywords: asynchronous motor, transient process, discrete macromodel Słowa kluczowe: maszyna asynchroniczna, stany nieustalone, makromodele dyskretne Introduction The creation of effective mathematical models intended for analysis of transient processes in electromechanical systems (EMS) elements is an important and relevant scientific problem. In the presented paper the research of the effectiveness of existing mathematical models of the electromechanical systems elements on the example of mathematical models of asynchronous motor was carried out. Traditionally, asynchronous motor is considered as a system of windings with magnetic coupling, which parameters are active resistances and inductances, and the processes in the electric machine must be analyzed using equations of electrical and mechanical equilibrium. The algorithm intended for calculation of the electric equilibrium equations makes it possible to define dependence of these parameters as a function of magneto motive force and machine slipping. These dependencies are presented in the form of mathematical models of the electric machine for the transient processes analysis [4,6]. Determination of parameters of electric and mechanical equilibrium equations, provided the correct processing of the results of the calcul[...]

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