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EN
The popularity of asynchronous machines, particularly squirrel cage machines, stems from their inexpensive production costs, resilience, and low maintenance requirements. Unfortunately, potential flaws in these devices might have a negative impact on the facility's profitability and service quality. As a result, diagnostic tools for detecting flaws in these types of devices must be developed. Asynchronous machine problems can be diagnosed using a variety of methods. Signal processing techniques based on extracting information from characteristic quantities of electrical machine operation can provide highly useful information about flaws. The purpose of this research is to develop efficient algorithms based on numerous signal processing approaches for correctly detecting asynchronous cage machine rotor defects (rotor bar ruptures).
EN
This paper aimed with diagnosis of defects in asynchronous machine. The used method is based on the exploitation of the behavioural laws of magnetostrictive and piezoelectric materials, under harmonic regime, used in the construction of the asynchronous machine. Piezoelectric sensors are used both in the stator and in the rotor. The used one in the stator serves to detect the rupture at the stator windings and the one used in the rotor helps us to detect the rupture of the rotor bars. The produced electric potential in the terminals of piezoelectric sensor is due to the deformation generated by magnetic induction under the effect of magnetostriction. A finite element method (FEM) is selected to be the resolution numerical method. This method is used for modelling the asynchronous machine under anomaly conditions and non-load.
PL
Przedmiotem artykułu jest transformator obrotowy. Służy on do przekazywania energii z części nieruchomej do części wirującej. Umożliwia bezstykowy przekaz energii, dlatego może być zastosowany w maszynie synchronicznej w celu eliminacji szczotek. W artykule przeprowadzono optymalizację, która pozwoli na zaproponowanie takiej konstrukcji z wykorzystaniem do tego celu rdzeni ferrytowych. Transformator obrotowy będzie zasilany napięciem o częstotliwości rzędu kiloherców, do wykonania uzwojeń została zaproponowana lica.
EN
The following paper covers rotary transformer topic. Duty of this device is to deliver energy from stator part to rotary part. This provide contactless energy transfer. Due to it can be used in synchronous machine in accordance to eliminate brushes. In this paper was conducted optimization process which provide to propose such design with use of ferrite cores. It will be supply with square voltage with range of kHz with litz wire winding.
4
Content available remote Evaluation of Discrete Modeling Efficiency of Asynchronous Electric Machines
EN
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.
PL
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.
PL
Przedstawiono możliwość zastosowania sterowania wymuszającego dynamikę w powiązaniu ze sterowaniem połowo zorientowanym do regulacji mocy maszyny asynchronicznej dwustronnie zasilanej.
EN
The paper presents the possibility to apply dynamics forcing control system interrelated with field-oriented control system for control of power of double-fed asynchronous machine.
PL
Zaprezentowano zastosowanie metody sterowania wymuszającego dynamikę do regulacji prędkości i mocy biernej maszyny dwustronnie zasilanej. Układ sterowania zrealizowany został w układzie współrzędnych związanych z wirnikiem, a jego struktura zapewnia minimalne sprzężenie torów regulacji. Przedstawiono syntezę praw sterowania i przykładowe wyniki symulacji pracy układu w wybranych trybach dynamicznych. Opisano zastosowanie obserwatora momentu obciążenia i wynikającą z niego odporność na zmiany momentu bezwładności układu.
EN
Application of Forced Dynamics Control method for speed and reactive power control of the doubly fed induction machine is presented in this paper. Control system works in co-ordinate system connected with rotor and good control path decoupling is provided. Speed and reactive power control laws synthesis is presented with simulation results of work in typical dynamic modes.
EN
The paper describes a precise method of approximation the relations between the flux linkages of the windings and the first and the third harmonic of MMF, generated by the windings currents. These nonlinear functions are approximated by a Fourier series of the first harmonic position and by the two-variable polynomials of the amplitudes of the both harmonics. They were formulated basing on the co-energy function of main magnetic field. The parameters of the polynomials are estimated base on the results of the field modelling. Shown results of the direct and indirect estimation method confirm the correctness of the proposed ways of the calculations. Presented method is designed to more precise modelling with circuit methods, the saturation effects in asynchronous machine.
PL
W artykule zaprezentowano zastosowanie sterowania wymuszającego dynamikę (FDC) do maszyny asynchronicznej dwustronnie zasilanej. Sterowanie FDC oparte zostało na metodzie połowo zorientowanej. Przedstawiono ideę sterowania FDC oraz jego adaptację do regulacji prędkości maszyny oraz mocy biernej pobieranej z sieci. Zaprezentowano wyniki badań laboratoryjnych napędu pracującego przy wymuszeniu kilku zadanych stanów przejściowych. Przedstawiono też wyniki badań dotyczących odporności układu na zmianę momentu bezwładności oraz wyniki badań układu pracującego z nadrzędnym regulatorem prędkości.
EN
Application of forced dynamics control (FDC) based on the field oriented control method for control of a doubly fed induction machine (DFIM) is presented in the paper. The idea of the FDC method and its adaptation to the control of speed and reactive power of the DFIM is described. The paper contains the laboratory test results of the DFIM working in three exemplary dynamic modes. The investigations of the influence of the moment of inertia on speed regulation and of the system of speed regulation with master control loop were performed and are described in the paper.
EN
The problems pertaining to capacitor-excited asynchronous machines, working as generators, are described. With the new experimental method, excitation characteristics were estimated for the machine working at a constant frequency. Based on the equivalent circuit diagram, the external characteristics were also obtained and compared to the experimantal ones. As a result, the conditions to stabilize the voltage by capacitors for different loads were formulated.
PL
Diagnostykę maszyny indukcyjnej prowadzi się zwykle w oparciu o sygnały wartości chwilowych prądów fazowych. Metody te związane są zwykle z wykonywaniem analizy harmonicznej tych przebiegów. Składowe harmoniczne wynikające z pogorszenia stanu maszyny mają stosunkowo małe wartości amplitud, czego efektem są problemy związane z interpretacją wyników analiz. Większość dostępnych w literaturze prac dotyczących diagnozowania maszyn indukcyjnych dotyczy maszyn zasilanych napięciem sinusoidalnym z sieci. Jedynie w ostatnich latach pojawiły się publikacje związane z badaniami diagnostycznymi przy zasilaniu maszyny ze źródeł o odkształconym napięciu.
EN
Diagnostics of induction motor is usually executed on the basis of the motor phase currents signals. The harmonic contents of the current signal are taken into account. The current harmonic components of the motor to be destroyed have relatively small amplitudes, what outcomes many problems connected with interpretation of analysis results. The most of papers referred to diagnostics of induction motors available in literature are involved to motors supplied by sinusoidal voltage. The present-day motor drives are using various converter devices with very varied control algorithms for motors control. The output voltage signal contain then many harmonic components, which make difficulties to the methods use. Therefore, the necessity appears to search for quality indicators providing estimation of motor drive state as the integrity, also including the figures of supplying voltage other than sinusoidal. The advantages of using for that purpose the value of true RMS stator current signal are presented in the paper (1). With the constant load torque assumption, the calculated as true RMS value has the constant component I0. This component is involved with the multiplicity com-ponents of the basic stator current component. Depending on the motor conditions the harmonic components frequencies depend on the motor rotation speed. The article presents the ability of uses of the value calculated as true RMS for diagnostics of the motor drive with asynchronous motor and a voltage inverter. The theoretical analyses are supplied by the presentation of labor test results with modeling of chosen damage states.
EN
Results of numerical modeling of squirrel-cage asynchronous motor with rotor circuit damages are presented in the paper. Possibilities of machine state rating in normal exploitation, based on the moving RMS signal and also proposed motor drive state estimation factors are also included. For modeling of the machine and proposed algorithm, the original program solution based on built C++ class library had been used. It had been shown, that the application of currents and voltages symmetry estimation factors and moving RMS currents and voltages diagrams oscillation estimation factors provides the identification of damage location. Analysis of proposed factors values makes the basis for indicating of damage location - either the supply source, or the stator circuit, or the rotor circuit asymmetry. Modeled damages have shown that not only the number of damaged rotor bars, but especially their symmetry in the rotor circuit has relevant meaning. Presented simulation results are being used for testing of proposed algorithms and building of a diagnostic device, based on Analog Devices SHARC 21065L processor.
PL
W artykule opisano układ bezpośredniego sterowania momentu (DTC) maszyny indukcyjnej dwustronnie zasilanej. Podano zasady sterowania momentu elektromagnetycznego silnika i mocy biernej w obwodzie stojana maszyny. Omówiono zalety i wady metody DTC oraz przedstawiono modyfikację metody, polepszającą właściwości układu. Przedstawiono wybrane wyniki badań symulacyjnych oraz laboratoryjnych.
EN
The direct torque control system of a double-fed induction machine is de-scribed in the paper. The principles of the control of the motor torque and of the reactive power in the stator circuit are presented. Advantages and faults of the DTC method are discussed and a modificated algorithm, ensuring better quality of the machine operation is proposed. The chosen results of simulation and experimental tests of the machine con-trolled according to the described method are presented in the paper.
PL
W artykule przedstawiono model matematyczny oraz program symulacyjny dynamiki silnika asynchronicznego uwzględniający uszkodzenia klatki wirnika. Prezentowany program zrealizowano przy użyciu techniki programowania obiektowego w języku C++. Rozwiązanie takie daje możliwość szybkiej budowy aplikacji ułatwiającej testowanie algorytmów diagnostycznych.
EN
The mathematical model and a program for simulation of dynamics of an asynchronous motor, including the damages of rotor bars, are presented in the paper. The presented program has been implemented using object-oriented programming techniques in C++ language. Such a solution gives an ability of quick building of applications, which can be used for testing of diagnostic algorithms.
14
Content available remote Analiza falkowa przebiegów maszyny asynchronicznej
PL
Do obliczenia przebiegów zmiennych stanu maszyny asynchronicznej zastosowano model "multislice 2.5D". Model ten oblicza pole magnetyczne w przekrojach prostopadłych do osi maszyny wykorzystując metodę elementów skończonych. Dla celów analizy guasi-stacjonarnych przebiegów w maszynie przedstawiono alternatywną do metody krótkoczasowego przekształcenia Fouriera (STFT) metodę falek (wavelet). Przedstawiono propozycję rozwiązania trudności numerycznych związanych z implementacją tej metody.
EN
A multislice, 2.5 dimensional model was used to calculate the state variables waveforms of the asynchronous machine. In this model, a magnetic field is calculated, in orthogonal to the machine's axis, two-dimensional intersections with the use of the finite element method. The wavelet transform was used to visualize the waveform's harmonic components. The performed analysis showed that the wavelet transform can be successfully used in the analysis of the asynchronous machine's waveforms, as an alternative to the short time Fourier transform.
EN
The rotating magnetic field in a symmetrical induction machine supplied with a sine-shaped and balanced system shows an asymmetrical shape if the magnetic medium is anisotropic. The shape of the air gap magnetic flux distribution is repeated twice per one revolution of the rotating field in a two-pole machine. The harmonic analyses show that all components rotate with variable magnitudes and non-uniform speeds. The variations are greater if the order of the component is higher. Only odd harmonics occur. Due to the spatial dependence of reluctance and the electric voltage balance in an induction machine, the magnetizing current also shows a spatial dependence.
EN
The torques of a magnetic brake and a solid rotor induction machine, fed by sinusoidal voltage sources, are simulated by a motional finite element method. Oscillatory solutions occurring for motional models with elevated velocities, are prevented by adaptive mesh refinement relying upon intermediate solutions stabilised by upwinded finite element test functions. A relaxed successive approximation deals with the non-linear material properties. The connections of the conductors and windings within the finite element model to external loads, impedances and supplies are represented by an electric circuit and added to the system of equations. The technical examples indicate the advantages of the motional formulation.
EN
The paper presents a model of induction machines, in which saturation for both the main and leakage fluxes of individual windings is represented. The model operates with the real winding currents what gives a chance to model saturation of leakage magnetic circuits separately for each winding. The saturation of the main magnetic circuit is modelled by introducing a magnetising current denned analytically by all machine currents. Such a model allows to study the interaction of saturation of separately treated magnetic circuits of the main and leakage fluxes. Remarkable results of simulations are shown in the paper.
EN
In the paper comparative studies of 2D-3D disc-type Switched Reluctance Motor (SRM) structures are performed. The calculation of magnetic field distributions and the static torque characteristics have been computed by means of Finite Element Method (FEM) for 2D and 3D motor structures. It has been emphasized that the calculations of the model structure (thanks to axial symmetry) have been done for a half of the volume while the boundary conditions are predefined. 3D structure of the model motor is built up, then the mesh is generated for number of elements exceeding 100 000. The results of 3D calculations are presented in the form of the static torque characteristics and magnetic flux curves versus rotor angular positions and current densities in the stator winding as well. Disc-type SR motors thanks to their specific structures are commonly used in automotive system, servo-drives, etc. The motor structure consists of the stator core toroidally shaped in which slots are placed on both sides of the active surface; moreover stator windings are wounded as Gramma type (made of identical coils surrounding the stator core). SRM are proposed to be mounted at the wheel of gearless electric vehicles (small cars, wheelchair, scooters, etc.).
EN
The paper presents an analysis of the magnetic field in a disk-type induction motor with double-sided stator and twin rotors. The magnetic flux density was found in a 3-D space using the reluctance network method (RNM). The results were compared with the measurements carried out on the real object.
EN
The paper presents the results of experimental verification of an analytical field model of a squirrel cage induction motor. Basic properties of the model are presented. Methods employed in the measurement are described. The obtained torque measurement data are compared with the simulation results for a selected machine prototype.
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