Wyniki 1-10 spośród 10 dla zapytania: authorDesc:"Andrii KALINOV"

An algorithm for electric circuits calculation based on instantaneous power component balance

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A method for nonlinear circuit calculation based on the algorithm of formulation and solution of instantaneous power components balance equations has been developed and verified. The offered algorithm of instantaneous power components formation is grounded on the discrete convolution of two series and implemented using MathCad mathematical package. The presented algorithm has been applied for calculation of a nonlinear inductance circuit at sinusoidal supply voltage. Streszczenie. W pracy rozwinięto oraz zweryfikowano metodę obliczania obwodów elektrycznych nieliniowych, bazującą na równowadze mocy chwilowej. Pokazany algorytm formowania składników mocy chwilowej ma podstawę w dyskretnym splocie dwóch szeregów i jest zrealizowany w pakiecie MathCad. Przedstawiony algorytm służy do rozwiązywania obwodu z nieliniowymi indukcyjnościami. ,(Algorytm obliczania obwodów elektrycznych bazujący na równowadze mocy chwilowej) Key words: nonlinear electric circuit, nonlinear inductance, instantaneous power, harmonic balance, discrete convolution. Słowa kluczowe:nieliniowy obwód elektryczny, indukcyjność nieliniowa, moc chwilowa, równowaga harmonicznych, splot dyskretny Introduction Calculation of nonlinear electric circuits underlies the analysis of various electric devices. An efficient and easily applied calculation method is necessary for attainment of sufficient accuracy of determining the parameters of electric circuits of electrical devices containing various nonlinear elements [1]. Calculation of nonlinear electric circuits is known to be reduced to calculation of nonlinear equations describing physical phenomena in electric circuits. Analysis of the literature revealed the small parameter method [2] to be a common representative of classic methods of such equations solution [2]. The use of this method is limited by the following faults: complication of calculation dependences with every consequent approximation and with increase of the[...]

Comparison of induction motor diagnostic methods based on spectra analysis of current and instantaneous power signals

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The comparison of effectiveness of induction motors fault detection methods based on experimental results analysis is presented. Researches showed possible disadvantages of the current spectra analysis method and advantages of the method based on phase power and total three-phase instantaneous power spectra analysis[...]

Sensorless vector-control system with the correction of stator windings asymmetry in induction motor

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Estimation of induction motor stator windings asymmetry influence on power and dynamic characteristics of sensorless vector control systems is performed. A system of vector control in a three-phase coordinate system is developed. This system makes it possible to compensate for induction motor windings asymmetry by correction of flux linkage assignment. Streszczenie. Analizowano wpływ asymetrii uzwojeń twornika silnika indukcyjnego na właściwości dynamiczne przy sterowaniu bezczujnikowym. Badano układ silnika trójfazowego. Przedstawiono metody korekcji wpływu asymetrii uzwojeń. (Bezczujnikowe wektorowe sterowanie silnikiem indukcyjnym z korekcją asymetrii uzwojeń) Key words: asymmetry, stator windings, power characteristics, vector control system. Słowa kluczowe: silnik indukcyjny, sterowanie bezczujnikowe, asymetria uzwojeń Introduction Sensorless induction motor (IM) vector control systems (VCS) are widely spread in industry. Long-term performance of IM results in occurrence of various damages. As diagnostics results show [1], at present, a great number of IM with unsymmetrical stator windings are used. According to statistic data, more than half IM failures occur due to stator windings damages [2, 3]. The main reason for this consists in damages of conductor and slot insulation which can be caused by both violation of motor production or repair methods and abuse. It results in short circuits: winding short circuits, interfacial ones and ironwork faults [4, 5]. As, due to the crisis, industrial enterprises reduce the amount of repair work, when some sections of stator winding of high- and medium-power motors fail, these sections are not removed out of the slots, but are excluded from the circuit and the sections ends are connected passing over the faulty ones [3]. As a result, the stator winding becomes asymmetric and henceforth the motor operates with this winding. Consequences of operation of IM with unsymmetrical stator wi[...]

Estimation of the efficiency of vibration power application for induction motor diagnostics DOI:10.12915/pe.2014.12.43

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A method for calculation of an induction motor vibration power in frequency domain on the basis of harmonic composition of the signal of vibration acceleration or vibration velocity is offered. When this method is realized, there are no problems connected with integration of continuous signals in time domain. To estimate the efficiency of the proposed method the root-mean-square values of vibration power are calculated on the basis of harmonic composition of vibration velocity for most common induction motors fault types. It is shown that, when the root-mean-square values of vibration velocity are the same, the root-mean-square values of vibration power significantly differ, which may result in wrong diagnostics of induction motor faults. Streszczenie. W artykule zaproponowana została metoda obliczeń drgań mocy silników indukcyjnych w obszarze częstotliwościowym przy użyciu składowych harmonicznych sygnału akceleracji bądź szybkości drgań. Podczas używania tej metody nie u8jawniają się problemy związane całkowanie sygnałów ciągłych w obszarze czasu. Aby oszacować efektywność proponowanej metody wartości skuteczne mocy drgań zostały obliczone na podstawie składowych harmonicznych szybkości drgań dla większości typów defektów silników indukcyjnych. Zostało pokazane, że podczas gdy wartości skuteczne prędkości drgań są takie same, wartości skuteczne mocy drgań są znacząco różne. Stąd może wynikać błędna diagnostyka defektów silników indukcyjnych. (Oszacowanie efektywności zastosowania drgań mocy do diagnostyki silników indukcyjnych) Keywords: vibrating power, velocity, harmonic structure. Słowa kluczowe: moc drgań, prędkość, struktura harmoniczna. doi:10.12915/pe.2014.12.43 Introduction Energy conversion in induction motors (IM) is inevitably connected with occurrence of variable forces and moments giving rise to vibration. Spectral and phase characteristics of vibration shift, vibration velocity and vibration acceleration are widely used [...]

An analytical method for calculation of passive filter parameters with the assuring of the set factor of the voltage supply total harmonic distortion DOI:10.15199/48.2017.12.49

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Decrease of the higher harmonics (HH) level in electrical networks is a part of the general problem of reduction of nonlinear load influence on the supply network and improvement of the quality of electrical energy in electricity consumption systems [1]. Nowadays the solution to this problem is based on the use of passive filter-compensating devices (FCD). Unlike power active filters [2-3], FCDs are the simplest and most economical filters, which caused their widespread use. FCDs are designed individually for every particular case of their application [4-7]. It guarantees the possibility for attaining the highest parameters of HH filtration. The data necessary for FCD design: 1) rated voltage; 2) the required compensation for the reactive power at the reference frequency; 3) the values of the currents of nonlinear load harmonic components; 4) the network short circuit power; 5) the required parameters of the electrical energy quality at the nonlinear load power lines (or at another point of contiguity) [4-7]. It should be noted that the correct calculation of the passive filter parameters is impossible without a qualitative analysis of the currents harmonic composition which is generated by the nonlinear load [8-9]. Also, it should be mentioned that most methods for calculation of the passive filter parameters are numerical. An essential disadvantage of such calculation of the filter optimal parameters consists in the fact that it is not always possible to unambiguously determine the degree of reduction of voltage supply total harmonic distortion (THDU). Problem statement Development of the method for calculation and choice of passive filtration devices that will enable determination of the passive filter parameters depending on the required factor of distortion of the THDU. Material and results of the research As the problem of the analysis of electricity supply systems can be reduced to the calculation of electric circ[...]

An Algorithm for Induction Motor Monitoring System Based on Electrical Signals Analysis DOI:10.15199/48.2018.06.03

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Modern technologies allow one ensure comprehensive control of production operation, which increase its reliability and efficiency. However, sudden failures of operational equipment could lead to production breaks, which, in turn, lead to financial losses. As induction motors (IM) are used to drive predominant number of actuating mechanisms, theirs failures cause most significant financial losses and could lead to failure of other industrial equipment. In order to avoid significant financial losses due to production stoppage because of sudden IM failure it is reasonable to use monitoring systems at important parts of production process. Such systems should use data for analysis which could be easily measured and don’t need expensive additional equipment. The best choice, in this case, is collection data from electrical signals for further analysis. As it was stated in [1], induction motor diagnostics and monitoring, as well as its life forecast and necessity of maintenance, could be done basing on analysis of electrical energy transformation process. One of the features describing energy processes in IM is its power consumption. This signal is quite suitable to be chosen as a basis for IM diagnostic and monitoring system, as it doesn’t require suspension of production, and needs only motor’s measured currents and voltages, while all the rest necessary features could be computed indirectly. Moreover, power spectra signal analysis is more reliable than current spectra analysis and contain additional information which could be used for evaluation current motor technical conditions [2]. In [3] it were derived mathematical expressions for determination power spectra frequencies related to most frequently caused IM damages. However, low-quality of supply mains, electrical disturbances and simultaneous presence of several damage types could cause difficulties in diagnostics basing on these frequencies. Thus, ther[...]

The review of methods and systems of the fault-tolerant control of variable-frequency electric drives DOI:10.15199/48.2019.01.36

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Introduction Correct functioning of variable-frequency electric drives (VFD) with induction motors (IM) depends on the reliable operation of IM, a three-phase autonomous voltage invertor (AVI), and a control system (CS). IM malfunctions include failures of: - one or several phases of the stator; - electrical asymmetry; - magnetic asymmetry; - mechanical breaks, etc. AVI malfunctions include: - the failure of a separate semiconductor switch; - the failure of one or two invertor arms; - the malfunction or failure of the control driver, etc. CS malfunctions include: - the break of angular rotation frequency sensor; - the break of the current sensors; - the breaks at the formation of the control signals, etc. The share of IM malfunction is the biggest in the whole scope of VFD failures. When IM operates with insignificant defects or with the breaks at the early stages of their development the system maintains its operability. In this case the quality of control deteriorates; the indices of the energy efficiency of the process of the electromechanical energy conversion decreases, the losses increase essentially and variable components of the electromagnetic torque and consumed active power appear. In such cases fault-tolerant control systems (FTC) are of great interest. They usually consist of two parts: the system of diagnostics and fault revelation and the system of the formation of special control impacts for their compensation. The scope of FTC systems is determined by the elements for which it is important to maintain an operational state in case of damage, despite the reduction in power, speed and energy efficiency: - electric transport drive; - electric drive of critically important technological objects; - electric drive of fire pumps, pumping stations of public water supply and water disposal; - electric drive of ventilation systems. Problem statement With the given significant number of developed fault toler[...]

Decrease of the thermal overloads of a variable-frequency electric drive at damages in the electric circuit of an induction motor stator DOI:10.15199/48.2019.05.11

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Damages in the stator power electric circuits stand out of the main causes of induction motors (IM) failure. Therefore, according to the research [1], the cause of 25% - 40% of IM failures consists in turn-to-turn shorting resulting from the stator winding insulation damages. The occurrence of turnto- turn shorting in the windings of IM of alternating current variable-frequency electric drives (ED) results in local overheat of particular semiconductor switches of frequency convertors (FC). A break of the whole winding or a parallel section of IM phase winding is a logical development of the turn-to-turn shorting. For IM with the number of parallel winding paths exceeding four a break of one path results in the asymmetry of the stator winding three-phase system and usually ends in the motor emergency outage. ED operation with asymmetric windings of the stator phases may also result in thermal overloads of particular FC switches and IM phases [2]. Timely detection and elimination of IM damages at the early stages of their development may increase the life span of the technological equipment and reduce the financial losses caused by unpredictable disconnection of the equipment resulting from technological faults or IM failure. Thus, fault-tolerant control systems (FTC) are of special interest as they are able to detect various types of damages at the initial stage and operatively adapt the control law in such a way that ED functionality remains for a long time till there is a possibility of IM repair or change [3]. There are two groups of the conventional methods of fault-tolerant control of IM with damages in the stator power electric circuit. The first group includes methods only allowing the detection of occurring damages and the termination of ED operation at their further development [4, 5]. This group may also include software redundancy methods based on the switch between the control algorithms from complex to simpler[...]

A diagnostic of induction motors supplied using frequency converter basing on current and power signal analysis DOI:10.15199/48.2016.12.02

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Abstract. The paper describes a way for providing induction motor diagnostic in case of motor fed using frequency converter, when additional distortions caused by pulse-width modulation could affect the diagnostic result. It is proposed to use preliminary clarification of current and voltage signals, aimed to exclude from consideration harmonics caused by pulse-width modulation, with further re-computation of power spectra using discrete convolution algorithm. Streszczenie. Artykuł opisuje metodę diagnostyki silnika indukcyjnego zasilanego przetwornikiem częstotliwości w przypadku występowania zakłóceń spowodowanych modulacją szerokości impulsu. Zaproponowano wstępne oczyszczanie sygnałów prądowych i napięciowych mające na celu wyłączenie z rozważań harmonicznych generowanych modulacją szerokością impulsu. Prowadzi to do ponownego obliczania spektrum mocy z wykorzystaniem dyskretnych algorytmów konwolucyjnych. (Diagnostyka silników indukcyjnych zasilanych z przetworników częstotliwości opartych na analizie sygnałów prądu I mocy) Key words: induction motors, fault diagnosis, instantaneous power, frequency domain analysis, frequency converters. Słowa kluczowe: silniki indukcyjne, diagnostyka uszkodzeń, moc chwilowa, analiza częstotliwościowa, przetworniki częstotliwości Introduction Nowadays reliable operation of induction motors (IM), as one of the biggest energy consumers that are used almost at all fields of industry, is very important task. To ensure their safety and reliability, it is essential to provide diagnostics of IM technical conditions. Traditional diagnostic techniques determine suspension of production, and partly disassembling of IM along with harmful testing operations. Thus, alternative diagnostic techniques become popular last years. These techniques allows one to provide diagnostic under operational conditions, they are not harmful for equipment, have well-grounded theoretical basis and provide reliable results. The[...]

Experimental research of the loading system for an induction motor with the use of a double-fed machine DOI:10.15199/48.2017.01.42

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The performed analysis of different systems for testing induction motors under load with the use of a frequency converter enables choosing the most rational variant taking into consideration the specific conditions of the production. The specific character of use of a double-fed machine in generator mode for testing induction motors with different number of ports in loading operating modes was investigated. Conducted experimental research confirms a possibility of creation of a loading mode for induction motors with different number of ports using double-fed machines with recuperation of both active and reactive power into supply mains. Streszczenie. Przedstawiono analizę różnych systemów testowania silników indukcyjnych pod obciążeniem z wykorzystaniem przetwornika częstotliwości, który umożliwia wybranie najbardziej racjonalnego wariantu z punktu widzenia specyficznych warunków produkcyjnych. Przebadany został specyficzny charakter wykorzystania podwójnie zasilanej maszyny w modzie generatorowym do testowania silników indukcyjnych. Przeprowadzone badania eksperymentalne potwierdziły możliwość utworzenia modu obciążenia silnika indukcyjnego z różną liczbą wejść w sytuacji kiedy liczba wejść jest różna przy użyciu podwójnie zasilanych maszyn z odzyskiwaniem zarówno energii biernej jak i czynnej do zasilających jednostek. (Badanie eksperymentalne system obciążenia silnika indukcyjnego z użyciem podwójnie zasilanej maszyny) Key words: induction motors, frequency converter, double-fed machines, load test Słowa kluczowe: silniki indukcyjne, przetworniki częstotliwości, podwójnie zasilana maszyna, test obciążenia Introduction Besides modern diagnostic methods by parameters of electric instantaneous [1] and vibration [2] powers the one of the ways to test induction motors (IM) is to test them under loading conditions [3, 4]. In spite of indirect methods of determination the energy characteristics [5] and loadcarrying capacity of the IM, testin[...]

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