Browsing by Author "Matviychuk, Yaroslav"
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Item Algorithm for identification of differential macromodel(Видавництво Львівської політехніки, 2011) Matviychuk, Yaroslav; Pauchok, VolodymyrTo provide a detailed description of the algorithm identifying differential macromodelling.Item Definition of dynamic system dimension on an output signal through correlation dimension in a pseudo-phase space(Видавництво Львівської політехніки, 2005) Matviychuk, YaroslavThe universal method is described which allows to receive a reliable estimation of a nonlinear system dimension only by one scalar output signal, at this the estimation does not depends on what an output signal of the system is used.Item Induction motor macromodel based on experimental data(Publishing House of Lviv Polytechnic National University, 2014) Matviychuk, YaroslavThe macromodel of transients of a threephase induction motor in the terms of stator current, rotation rate and loading on the axis is described. Experimantal data are averaged per an alternating current (AC) period. Regularization of the experimantal data differentiation is demonstrated using cubic smoothing splines. The number of coefficients of macromodel is minimized by reduction of the approximating polynomial. Due to the reduction of macromodel the identification became correct. Adequate behavior of the macromodel has been verified for input signals different from those for which the macromodel has been built. Experimental transients are reproduced by two continuous nonlinear maсromodels of the first order with a relative mean square error less than 1%. The received macromodel is notable for its low order and high-fidelity output signals. Описано макромодель трифазного асинхронного двигуна, отриману для таких параметрів, як навантаження на валу, струм живлення однієї з фаз та частота обертання ротора. Експериментальні дані усереднено за період змінного струму живлення. Продемонстровано регуляризацію обчислення похідних вихідних сигналів макромоделі за допомогою згладжуючих кубічних сплайнів. Кількість коефіцієнтів макромоделі мінімізовано за методом редукції апроксимуючого поліному. Завдяки редукції ідентифікація макромоделі стала коректною. Адекватну поведінку макромоделі перевірено на сигналах, відмінних від сигналів, за якими збудовано макромодель. Експериментальні перехідні процеси відтворено двома нелінійними макромоделями першого порядку зі середньоквадратичною похибкою, меншою за 1 %. Отримана макромодель вирізняється гранично малим порядком і високою точністю відтворення вихідних сигналів.Item Mathematical macromodeling of dynamic systems and examples of macromodels(Publishing House of Lviv Polytechnic National University, 2006) Matviychuk, YaroslavThe problems of macromodeling of continuous nonlinear dynamic systems with lumped constant parameters are considering. The common modeling structure in the form of the system of ordinary differential equations is shown. The regularised methods of its identification are described. The examples of macromodels of different complexity and nature are given.Item Numerical synthesis of the macromodel of generator with soft excitation of oscillations with the help of the second method of Lyapunov(Видавництво Національного університету «Львівська політехніка», 2004) Matviychuk, YaroslavTheoretical substantiation of a method for providing the convergence of a solution of mathematical model of an independent system to a given solution with the help of the second method of Lyapunov is considered. The method is illustrated by model of the self-oscillator, for which the conditions of "soft" excitation of oscillations are provided.Item Peculiarities of approximations application to the identification of mathematical macromodels(Видавництво Львівської політехніки, 2012) Matviychuk, Yaroslav; Malachivskyy, Peter; Hasko, RomanThe problem of mathematical macromodeling electronic devices. The results of macromodeling using approximations by the method of least squares and chebyshev approximation for the frequency detector, multivibrator and oscillator. The expediency of the method of least squares to reproduce the original signal macromodels of nonlinear electronic devices.Item Reduction principle of the mathematical model(2017-07-07) Matviychuk, Yaroslav; Lviv Polytechnic National UniversityThe detection and elimination principle of redundant elements in the mathematical model is proposed in this paper. The efficiency of the proposed approach has been analyzed based on the neural network model of economic system and differential equations model. Results prove the 16 times increasing in the model accuracy.Item Syncronous generator macromodel(Odessa National Polytechnic University, 2006) Matviychuk, YaroslavThe regularised method of macromodel identification, based on the splitting of the signal spectrum and to select such basic functions of approximation, are described on the example of synchronous generator macromodel.Item Synthesis of determined system reconstracting the given random sequence(Overseas Publishers Associa, 1999) Matviychuk, YaroslavA synthesis method for the ordinary differential equations is proposed. Their solutions reconstruct the statistical properties of the given pseudo-random sequence. The method is illustrated by an example of simulating singular Lorenz attractor and the sequence of pseudo-random numbers whish are uniformly distributed within [0,1] interval.Item Сreating electronic device macromodels by quadratic and Сhebyshev approximation(Publishing House of Lviv Polytechnic National University, 2012) Matviychuk, Yaroslav; Malachivsky, Peter; Hasko, RomanIn the article the problem of mathematical macromodeling of electronic devices has been considered. The results of macromodeling by the least squares approximation and the Chebyshev approximation for frequency detectors, multivibrators, and oscillators have been shown. The efficiency of the method of least squares in reproducing the original signal macromodels of nonlinear electronic devices has been proved. У запропонованій статті розглядається проблема макромоделювання електронних пристроїв. Представлено результати макромоделювання частотного детектора, мультивібратора та осцилятора шляхом апроксимації методом найменших квадратів та апроксимації многочленами Чебишева. Показано ефективність використання методу найменших квадратів для створення макромоделей сигналів нелінійних електронних пристроїв.