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EN
In this comprehensive study, the concept and structural diagram of the system for diagnostics of induction electric motors of vehicles with the development of algorithms for the operation of modular units for monitoring the state of the main structural elements are proposed. During the development of the diagnostic system, the peculiarities of the construction of diagnostic systems of rotating electric machines were investigated in the real conditions of their operation, and modern methods of current and vibration diagnostics were implemented. The work algorithms of each module are presented in the functional diagram of the general diagnostic system of and cover important defects of induction motors. The diagnostic system combines methods that use different diagnostic principles and criteria and are adapted for use in an embedded diagnostic system. The developed functional diagram of the diagnostic system can be used for practical implementation in physical form. The use of the proposed diagnostic system will make it possible to obtain continuous information about the state of both electrical and mechanical components of the induction motor when operating under load with a poor-quality power system in real operating conditions.
EN
Traction drives with vector control are widely used on mainline locomotives with induction motors. Traction motors can fail due to malfunctions that occur during the operation of locomotives. Real-time functional diagnostic systems are necessary to prevent the failure of traction motors. The implementation of such systems will allow to detect the occurrence of malfunctions in the traction motor at the initial stage and prevent the further development of the defect. In the work, a structural diagram of functional diagnostics for monitoring the condition of the rotor of an induction motor is proposed and an algorithm for its operation is developed.
EN
Fault diagnosis techniques of electrical motors can prevent unplanned downtime and loss of money, production, and health. Various parts of the induction motor can be diagnosed: rotor, stator, rolling bearings, fan, insulation damage, and shaft. Acoustic analysis is non-invasive. Acoustic sensors are low-cost. Changes in the acoustic signal are often observed for faults in induction motors. In this paper, the authors present a fault diagnosis technique for three-phase induction motors (TPIM) using acoustic analysis. The authors analyzed acoustic signals for three conditions of the TPIM: healthy TPIM, TPIM with two broken bars, and TPIM with a faulty ring of the squirrel cage. Acoustic analysis was performed using fast Fourier transform (FFT), a new feature extraction method called MoD-7 (maxima of differences between the conditions), and deep neural networks: GoogLeNet, and ResNet-50. The results of the analysis of acoustic signals were equal to 100% for the three analyzed conditions. The proposed technique is excellent for acoustic signals. The described technique can be used for electric motor fault diagnosis applications.
EN
This article aims to implement the fuzzy control for an asynchronous motor after a general representation of the vector control. We develop MAMDANI type fuzzy algorithm for MAS speed regulation; it’s one purpose is to cancel static error, decrease overshoot, decrease response time, and rise time to obtain an adequate response of the process and regulation and to have a precise, fast, stable and robust system. This paper investigates the design of a fuzzy-based approach for monitoring the inversion of the rotational speed of an induction motor. We will indeed present a robust vector control technique ex-tended to blur in the event of a fault. Direct torque control is known to produce fast and robust response in the AC drive system. However, in a steady state, a rapid and unexpected change in speed can occur which could be dangerous. The performance of the conventional PID controller can be improved by implementing fuzzy logic techniques. The first step is the modelling of the whole system, including the capacitors, the induction generator and the loads. The model is obtained using the Park transformation. The results are thus compared with those of the standard PID control. This approach is applied to a three-phase asynchronous motor (LS90Lz). The presented study improves the transient response time and the precision of the servo system. An inversion of the reference speed of rotation is considered, and the results are very convincing.
PL
Przyczyny usterek silnika i napędu nie ograniczają się tylko do jednej dziedziny techniki. Zarówno mechaniczne, jak i elektryczne usterki mogą doprowadzić do awarii silnika, a więc odpowiednia wiedzy decyduje o poprawie niezawodności działania silnika a jego kosztownym przestojem. W artykule scharakteryzowano wybrane uszkodzenia silników oraz przedstawiono opracowane w ramach prac badawczych zabezpieczenie silnika średniego napięcia, które umożliwia predykcję uszkodzenia: klatek wirnika i stopnia jego degradacji, łożysk oraz sprzęgu silnika z maszyną napędzaną. W artykule przedstawiono wyniki prac badawczo-rozwojowych przeprowadzonych w firmie Elektrometal Energetyka nad zabezpieczeniami predykcyjnymi silników SN opartymi na analizie zdudnień.
EN
The causes of engine and drive malfunctions are not limited to just one area of technology. Both mechanical and electrical faults can lead to engine failure, so having the right knowledge determines the improvement of the reliability of engine operation versus its costly downtime. The article characterizes selected motor faults and presents the medium-voltage motor protection developed as part of the research work, which allows prediction of the following faults: rotor cages and the degree of degradation, bearings and the coupling of the motor to the driven machine. The article presents the results of research and development work carried out at Elektrometal Energetyka S.A. on predictive protections for medium-voltage motors based on the analysis of ripple.
6
Content available remote Park’s vector approach to detect broken rotor bars in saturated Induction motor
EN
This paper deals with the problem of broken rotor bars fault diagnosis in saturated induction motor. Several techniques such as those based on vibration, axial leakage monitoring, zero-sequence component, negative sequence current, and motor current signature analysis have been used. However, these techniques do not take into account the effect of magnetic saturation. This paper presents a current Park’s Vector method for diagnosis in squirrel cage induction motor with the presence of magnetic saturation. The use of a current vector pattern trajectory and Modulus current spectrum analysis demonstrate that deformation of the Current Park’s Vector Pattern trajectory and the presence of new harmonics are indicators for predicting magnetic saturation and broken bars rotor fault. Our experimental results allow us to discriminate between the magnetic saturation in healthy and faulty squirrel cage induction motors.
PL
W artykule podjęto problematykę diagnostyki pękniętych prętów wirnika w nasyconym silniku indukcyjnym. Zastosowano kilka technik, takich jak oparte na drganiach, monitorowaniu upływu osiowego, składowej zerowej, składowej przeciwnej prądu i analizie sygnatur prądu silnika. Techniki te nie uwzględniają jednak wpływu nasycenia magnetycznego. W artykule przedstawiono aktualną metodę Parka Vector do diagnostyki silnika indukcyjnego klatkowego z obecnością nasycenia magnetycznego. Wykorzystanie trajektorii wektora prądu i analiza widma prądu modułowego pokazują, że deformacja trajektorii wzorca wektorowego Current Park i obecność nowych harmonicznych są wskaźnikami do przewidywania nasycenia magnetycznego i uszkodzenia wirnika z pękniętymi prętami. Nasze wyniki eksperymentalne pozwalają nam rozróżnić nasycenie magnetyczne w zdrowych i uszkodzonych silnikach indukcyjnych klatkowych.
EN
The algorithms for calculating steady-state modes, static characteristics, and transients in an asynchronous drive based on a wound-rotor induction motor and a starter in a rotor circuit are presented. The calculation is based on a mathematical model of an induction motor that takes into account the saturation of the magnetic circuit. The electromagnetic processes are described by a nonlinear system of equations of electrical equilibrium composed in a fixed three-phase coordinate system, the coefficients of which are the differential inductances of the circuits. The steadystate modes and static characteristics are calculated by solving the boundary value problem using the continuation method in the parameter.
PL
Przedstawiono algorytmy obliczania trybów pracy w stanie ustalonym, charakterystyk statycznych i stanów nieustalonych w napędzie opartym na silniku indukcyjnym z wirnikiem fazowym i rozrusznikiem obwodu wirnikowego. Obliczenia oparte są na modelu matematycznym silnika indukcyjnego uwzględniającym nasycenie obwodu magnetycznego. Procesy elektromagnetyczne opisane są nieliniowym układem równań równowagi elektrycznej w ustalonym trójfazowym układzie współrzędnych, z indukcyjnościami różnicowymi obwodów jako współczynnikami. Tryby pracy w stanie ustalonym i charakterystyki statyczne oblicza się rozwiązując problem wartości granicznych metodą kontynuacji w parametrze.
PL
W artykule przedstawiono analizę bezpośredniego polowo-zorientowanego sterowania silnikiem indukcyjnym tolerującego uszkodzenia wszystkich czujników prądów stojana. Do detekcji i kompensacji uszkodzeń czujników prądu zaproponowano podwójny zmodyfikowany obserwator Luenbergera. Dodatkowo, w porównaniu do aktualnie stosowanych rozwiązań, zastosowanie opisanej modyfikacji wektora błędu obserwatora umożliwiło zwiększenie jego odporności na zmiany parametrów silnika oraz dokładności estymacji prądu stojana. Badania eksperymentalne potwierdziły wysoką skuteczność proponowanego rozwiązania.
EN
The article presents an analysis of direct field-oriented control of an induction motor that tolerates failure of all stator current sensors. A dual modified Luenberger observer has been proposed for the detection and compensation of faults in current sensors. Additionally, compared to recent solutions, the use of the described modification of the observer's error vector allowed to increase its robustness to changes in motor parameters and the accuracy of stator current estimation. Experimental studies confirmed the high effectiveness of the proposed solution.
PL
W artykule przedstawiono szczegółową analizę wpływu czasu martwego falownika napięcia (FN) oraz jego kompensacji na jakość estymacji prądu stojana stosowanej w układach napędowych z silnikami indukcyjnymi (SI), tolerujących uszkodzenia czujników prądu (CS-FTC). Badania zostały zrealizowane w zakresie niskich prędkości kątowych, wynoszących od 1% do 20% wartości znamionowej, zarówno dla pracy silnikowej jak i prądnicowej, dla różnych wartości czasu martwego. Wyniki pokazują istotną poprawę jakości estymacji prądu stojana, co jest szczególnie ważne w przypadku kompensacji uszkodzeń czujników prądu w napędach z SI.
EN
This article presents a detailed analysis of the impact of voltage source inverter (VSI) dead time and its compensation on the quality of stator current estimation used in the current sensor fault-tolerant control (CS-FTC) of induction motor (IM) drives. The tests were carried out in the low angular velocity range, from 1% to 20% of the rated value, both for motoring and regenerating modes, for different values of dead time. The results show a significant improvement in the quality of stator current estimation, which is particularly important in the case of fault compensation in IM drive systems that tolerate faults of current sensors.
EN
In this study, a long short-term memory (LSTM) based estimator using rotating axis components of the stator voltages and currents as inputs is designed to perform estimations of rotor mechanical speed and load torque values of the induction motor (IM) for electrical vehicle (EV) applications. For this aim, first of all, an indirect vector controlled IM drive is implemented in simulation to collect both training and test datasets. After the initial training, a fine-tuning process is applied to increase the robustness of the proposed LSTM network. Furthermore, the LSTM parameters, layer size, and hidden size are also optimised to increase the estimation performance. The proposed LSTM network is tested under two different challenging scenarios including the operation of the IM with linear and step-like load torque changes in a single direction and in both directions. To force the proposed LSTM network, it is also tested under the variation of stator and rotor resistances for the both-direction scenario. The obtained results confirm the highly satisfactory estimation performance of the proposed LSTM network and its applicability for the EV applications of the IMs.
EN
This article presents an active current sensor (CS) fault-tolerant control (FTC) strategy for induction motor (IM) drive with adaptation of rotor and stator resistances. The stator current estimator with online adaptation of resistance parameters was applied for the reconstruction of missing current signals. A model reference adaptive system (MRAS), based on a neural network (NN), was used to estimate the rotor resistance. Additionally, stator resistance estimation was applied based on ratio index. The use of such a solution allowed for a significant increase in the quality of stator current reconstruction, which is particularly important for the design of CS fault detection (FD) and compensation algorithms. A wide range of simulation studies have been carried out for different operating conditions of the IM drive. The results showed that applying rotor and stator resistance estimation can improve the quality of stator current estimation by up to approximately 95% under rated operating point. The study was carried out for nominal and low speeds, with two, one, and without healthy CS.
EN
Since the induction motor operates in a complex environment, making the stator and rotor of the motor susceptible to damage, which would have significant impact on the whole system, efficient diagnostic methods are necessary to minimize the risk of failure. However, traditional fault diagnosis methods have limited applicability and accuracy in diagnosing various types of stator and rotor faults. To address this issue, this paper proposes a stator-rotor fault diagnosis model based on time-frequency domain feature extraction and Extreme Learning Machine (ELM) optimized with Golden Jackal Optimization (GJO) to achieve high-precision diagnosis of motor faults. The proposed method first establishes a platform for acquiring induction motor stator-rotor fault data. Next, wavelet threshold denoising is used to pre-process the fault current signal data, followed by feature extraction to perform time-frequency domain eigenvalue analysis. By comparison, the impulse factor is finally adopted as the feature vector of the diagnostic model. Finally, an induction motor fault diagnosis model is constructed by using the GJO to optimize the ELM. The resulting simulations are carried out by comparing with neural networks, and the results show that the proposed GJO-ELM model has the highest diagnostic accuracy of 94.5%. This finding indicates that the proposed method outperforms traditional methods in feature learning and classification of induction motor fault diagnosis, and has certain engineering application value.
PL
W szeregu publikacjach prezentowane są przykłady licznych awarii silników indukcyjnych dużej mocy. Analizując przyczyny awarii silników, można wymienić szereg nietypowych przyczyn, których początkiem są przede wszystkim uszkodzenia o charakterze mechanicznym i zmęczeniowym. Niejednokrotnie skutki takich uszkodzeń prowadzą do poważnych awarii o charakterze katastrofalnym. Celem opisanej ekspertyzy było wyjaśnienie przyczyn wystąpienia awarii silnika o mocy PN = 630 kW i napięciu zasilania UN = 6000 V, który stanowił napęd sprężarki agregatu chłodniczego. Awaria silnika miała miejsce w podziemiach kopalni węgla kamiennego. W przypadku opisanej awarii silnika mamy do czynienia z przypadkiem szczególnym zaliczanym do tzw. awarii nietypowych. Choć taka kwalifikacja zdarzeń jest nieformalna to określa ona bardzo rzadkie przypadki ich występowania.
EN
In the following series of publications, examples of failures of high-power squirrel cage motors are presented. While analysing failure cases of motors, it is possible to list out number of unusual causes, the beginning of which are primarily mechanical and fatigue damage. Often the effects of such damage leads to serious catastrophic failures. The purpose of the expertise was to explain the cause of failure of motor with power of PN = 610 kW and supply voltage of UN = 6000 V, which was powering refrigeration unit. The failure occurred in underground mine of bituminous coal. In the described case, we are dealing with special case of so-called atypical failures. Although such a qualification is informal, it defines very rare cases of their occurence.
EN
The three-phase induction motor is well suited for a wide range of mobile drives, specifically for electric vehicle powertrain. During the entire life cycle of the electric motor, some types of failures can occur, with stator winding failure being the most common. The impact of this failure must be considered from the incipient as it can affect the performance of the motor, especially for electrically powered vehicle application. In this paper, the intern turn short circuit of the stator winding was studied using Fast Fourier transform (FFT) and Shor-Time Fourier transform (STFT) approaches. The residuals current between the estimated currents provided by the extended Kalman filter (EKF) and the actual ones are used for fault diagnosis and identification. Through FFT, the residual spectrum is sensitive to faults and gives the extraction of inter-turn short circuit (ITSC) related frequencies in the phase winding. In addition, the FFT is used to obtain information about when and where the ITSC appears in the phase winding. Indeed, the results allow to know the faulty phase, to estimate the fault rate and the fault occurrence frequency as well as their appearance time.
EN
In the work, studies were carried out on the use of vibration diagnostic methods for monitoring the state of induction motors with a squirrel-cage rotor, operated in electric drives of transport equipment. The most common and difficult-todiagnose damage to an induction motor is turn-to-turn short circuits in the stator winding, which require timely determination and establishment of the degree of damage to prevent an emergency shutdown of the equipment. The main purpose of the study is to establish the most effective areas of application of vibration diagnostic methods in determining the technical condition of the stator of induction motors under load. The experiments were carried out using simulation modeling for cases of turn-to-turn short circuits in one and two phases simultaneously, as well as with the influence of a low-quality supply voltage system on vibration parameters. The results of the work are relevant for further improvement of systems for diagnostic control of drives of transport equipment to increase the efficiency and reliability of their work.
PL
Celem badań było rozszerzenie możliwości monitorowania i diagnostyki maszyn elektrycznych na podstawie drgań maszyny. Autorzy zaproponowali bezinwazyjną metodę diagnostyczną uwzględniającą wielofazowe zwarcia międzyzwojowe w uzwojeniu stojana. W pracy przedstawiono i omówiono zarówno proces pozyskiwania sygnału diagnostycznego jak również opracowaną metodę diagnostyczną. Opracowaną metodę zweryfikowano.
EN
The aim of the research was to extend the possibilities of monitoring and vibration diagnostics of electric machines. The authors proposed a non-invasive diagnostic method taking in to account multi-phase inter-turn short-circuits in stator winding. The process of acquiring of the diagnostic signal and proposed diagnostic method have been presented, concluded and discussed. Moreover, the developed method was verified and the error of the proposed method was calculated.
EN
The aim of the research was to extend the possibilities of monitoring and vibration diagnostics of electric machines. The authors proposed a non-invasive diagnostic method taking in to account multi-phase inter-turn short-circuits in stator winding. The process of acquiring of the diagnostic signal and proposed diagnostic method have been presented, concluded and discussed. Moreover, the developed method was verified and the error of the proposed method was calculated.
PL
Celem badań było rozszerzenie możliwości monitorowania i diagnostyki maszyn elektrycznych na podstawie drgań maszyny. Autorzy zaproponowali bezinwazyjną metodę diagnostyczną uwzględniającą wielofazowe zwarcia międzyzwojowe w uzwojeniu stojana. W pracy przedstawiono i omówiono zarówno proces pozyskiwania sygnału diagnostycznego jak również opracowaną metodę diagnostyczną. Opracowaną metodę zweryfikowano.
EN
The use of specialized rail rolling stock which is used for transporting ore from the quarry to the crushing plant at mining enterprises is analyzed here. Electric locomotives with an asynchronous traction electric drive and an on-board energy storage system are considered for use. The calculated dependencies of the electric locomotive tractive power were analyzed and it was established that on flat sections of the track profile, the movement is carried out with a power that does not exceed 50% of the nominal one. The movement with the nominal power is carried out on the controlled uphill during the cargo half-passage. To ensure the necessary power for movement in such areas, the use of an on-board energy storage system is proposed, which should feed the traction system while limiting the power consumed from the catenary. This happens when the voltage on the pantograph drops to a minimum level. The aim of this work is to determine the on-board energy storage system parameters during the operation of the electric locomotive with limitation of the power consumed from the traction network. Mathematical models of the energy exchange processes in the electric locomotive traction system have been developed. The criteria for comparing options for calculating the parameters of the on-board energy storage system have been proposed. The criteria take into account the reduction of energy consumption during movement, the efficiency of energy storage, and the complete use of the on-board energy storage system in terms of power and working energy capacity. Based on the calculation results, it was determined that the use of an energy storage device with a power of 3,540 kW and an operating energy capacity of 63.5 kWh provides a 10% reduction in energy consumption, which is being consumed while moving along the sample section of the road. The current that can be consumed by an electric locomotive with such parameters of the on-board energy storage system is limited by 600 A.
EN
Induction motors (IMs) experience power losses when a portion of the input power is converted to heat instead of driving the load. The combined effect of copper losses, core losses, and mechanical losses results in IM power losses. Unfortunately, the core losses in the motor, which have a considerable impact on its energy efficiency, are not taken into account by the generally employed dynamic model in the majority of the studies. Due to this, the motor rating often corresponds to the worst-case load in applications, but the motor frequently operates below rated conditions. A hybridized model reference adaptive system (MRAS) with sliding mode control (SMC) is used in this study for sensorless speed control of an induction motor with core loss, allowing the motor to operate under a variety of load conditions. As a result, the machine can run at maximum efficiency while carrying its rated load. By adjusting the 𝛼-axis current in the 𝛼 𝛽 reference frame in vector-controlled drives, the system’s performance is enhanced by running the motor at its optimum flux. Regarding the torque and speed of both induction motors with and without core loss, the Adaptive Observer Sliding Mode Control (AOSMC) has been constructed and simulated in this case. The AOSMC with core loss produced good performance when the proposed controller was tested.
PL
Zwiększająca się konsumpcja, rosnące wymagania dotyczące niezawodności dostawy energii elektrycznej do odbiorców oraz trudności związane z budową nowych obiektów elektroenergetycznych są wyzwaniami, z którymi zmierzyć się musi nowoczesna automatyka zabezpieczeniowa. Współczesne cyfrowe sterowniki polowe o znacznych możliwościach obliczeniowych umożliwiają implementację dodatkowych funkcji w postaci procedur obliczeniowych lub algorytmów przetwarzania sygnałów. Pojawia się zatem możliwość przeprowadzenia udoskonaleń klasycznych algorytmów decyzyjnych zabezpieczeń przez budowę zabezpieczeń predykcyjnych i adaptacyjnych. W artykule przedstawiono wyniki prac badawczo-rozwojowych przeprowadzonych w firmie Elektrometal Energetyka nad zabezpieczeniami adaptacyjnymi i predykcyjnymi silników SN.
EN
Increasing consumption, growing requirements for the reliability of electricity supply to consumers, and problems associated with the construction of new electric power facilities are challenges faced by modern protection automation. Modern digital field controllers with significant computational capabilities allow the implementation of additional functions, in the form of computational procedures or signal processing algorithms. Thus, the possibility of carrying out improvements to classical security decision-making algorithms, through the construction of predictive and adaptive protection. The paper presents the results of research and innovation work carried out at Elektrometal Energetyka S.A. on adaptive and predictive protection of MV motors.
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