Czasopismo Techniczne z. 17. Elektrotechnika z. 1-E

Czasopismo Techniczne z. 17. Elektrotechnika z. 1-E

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The model of permanent magnet synchronous machines for diagnostic purpose

Węgiel, Tomasz
Article
2008
In this paper an analytical method of analyzing the flux density distribution in the air gap and the mathematical model for permanent magnet synchronous machines with non-uniform air gap are presented. The paper contains a way of calculating flux density distribution in the air gap for machine with eccentricity and shows the comparison results of calculation for simplified model and FEM. This approach is presented by an example of 3-phase PM synchronous machine.

Modelowanie silników karuzelowych

Węgiel, Tomasz
Article
2008
This paper deals with mathematic model of carousel motor. This motor is constructed with a stator typical for AC machines and with a rotor of a new design. The stator is traditionally used to produce p-poles sinusoidal EMF. The rotor consists of 2p rotors located over active surface of the stator, and each of them can rotate around its own axis. Rotors are situated on interior surface of stator. The principle of motor work depends on utilizing attractive forces between the stator and the rotors. The rotors try to take position which correspond to the position of the maximum energy of electromagnetic field produced by the stator winding. The paper presents the method of creation of mathematic models for carousel motors. The co-energy functions and produced electromagnetic torques for carousel motors are shown in the paper.

Analiza transferu napięcia przez przekształtnik macierzowy 9×3 z jednoczesną zmianą częstotliwości

Sobczyk, Tadeusz
Article
2008
This paper presents an analysis of a matrix converter with a specific topology, which enables to change a number of phases and frequency of the multi-phase voltage system. Such inverters can be applied in an electric energy generation line of small power stations, in which multi-phase synchronous generators driven by high speed gas turbine are applied. The Fourier spectrum of input voltages is investigated for a matrix converter changing a 9 phase voltage system with high frequency, of the order a few hundred Hz, onto the 3 phase voltage system with commercial parameters. In the paper an idea of the matrix converter control is presented, which allows to fulfil such voltage transformation. The analysis in the frequency domain gives analytical expressions determining quantitatively and qualitatively the Fourier spectra of output voltages at idealized performances.

Zastosowanie algorytmu mrówkowego do wyznaczania maksymalnej grupy wzajemnie połączonych elementów

Schiff, Krzysztof
Article
2008
In this paper an ANT algorithm, which is used to find a maximum group of mutually connected electronic elements in order to minimize the total length of connections, is presented. The new algorithm differs from algorithms which have been presented in scientific papers until now. The main difference is a phase of ANT exploration which is absent in other ANT algorithms. Sizes of maximum clique indicated by ANT algorithm and the Algorithm 457 are compared. The influence of the local search was presented also and the (2,1)-exchange local procedure and the ANT procedure of local search was compared.

Upraszczanie funkcji wymiernych

Piwowarczyk, Tadeusz
Article
2008
A rational function in electrical circuits represents, among others, a transient state or a transmittance. Such a function must be simplified before it is used in a calculus. The main problem with simplification is the Abel theorem. However, it can be overcome by a special approach. The theory of transient states developed around symmetric polynomials delivers the algebra procedure designed for this purpose. It is expressed in a clear matrix notation. A concrete numerical example of a proposed procedure is enclosed to the article.

Moc chwilowa w stanie nieustalonym. Reprezentacja w dziedzinie skończonych ciągów liczbowych

Piwowarczyk, Tadeusz
Article
2008
In most cases the formulation of the criteria for some chosen properties of linear electrical circuits in transient states does not require the time function solutions. It is sufficient to analyze the appropriate Laplace transform which is known to be easy to obtain. It is obvious in case of the current I(s) and the voltage V(s). The analysis of time power can be treated in an analogous way providing we know its Laplace transform. The article shows how to find the Laplace transform P(s) of the time power p(t) if we know the Laplace transforms of the current I(s) and the voltage U(s).

Wykorzystanie komputerowych generatorów liczb losowych w układach stochastycznych przetworników analogowo-cyfrowych

Pędrak, Grzegorz
Article
2008
W artykule scharakteryzowano układ przetwornika stochastycznego, jego budowę i zasadę działania. Przedstawiono znane metody generowania liczb pseudolosowych o rozkładzie równomiernym. Zaimplementowano algorytmy wybranych metod generowania liczb pseudolosowych (RNG) do postaci programowych komputerowych generatorów w języku C/C++. W wyniku symulacji otrzymano sekwencje rozkładów liczb pseudolosowych, a następnie dokonano analizy tych rozkładów na podstawie parametrów i odpowiednich testów statystycznych. Przeanalizowano celowość wykorzystania generatorów liczb pseudolosowych w przetwornikach stochastycznych A/C.

Wpływ bezwładności oraz nasycania się głównego obwodu magnetycznego na sygnały diagnostyczne mówiące o stanie klatki

Maciołek, Wacław
Article
2008
This paper presents results of the analysis of an influence of the moment of inertia and the non-linearity of the main magnetic circuit on basic diagnostic signals used for the condition monitoring of an induction motor cage. A relatively simple model is used for this, in which a cage asymmetry is represented by respective coefficients and a magnetic non-linearity is modelled by using the equivalent magnetising currents. Simulating tests shows that both the moment of inertia and non-linearity have important impact on values of components with frequencies (1 – 2s)f0 and (1 + 2s)f0 in the Fourier spectrum of stator currents, which are most popular diagnostics signals for the cage monitoring. In conclusions it has been stated that for an effective diagnose the cage state should be permanently monitored in order to find the beginning of cage destruction.

Identyfikacja rozkładu w systemach rzeczywistych za pomocą estymatorów jądrowych

Łukasik, Szymon
Article
2008
Metody nieparametryczne znajdują coraz szersze zastosowanie w zagadnieniach współczesnej analizy i eksploracji danych. W artykule przedstawiono najpopularniejsze narzędzie powyższych metod – estymatory jądrowe. Poza koncepcją tychże estymatorów zaprezentowano także praktyczne aspekty estymacji oraz przykłady jej zastosowań do wyznaczania rozkładów z dziedziny fizyki wysokich energii, wykrywania uszkodzeń silnika asynchronicznego oraz analizy danych socjologicznych.