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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 modern drive systems, the high-efficient permanent magnet synchronous motors (PMSMs) have become one of the most substantial components. Nevertheless, such machines are exposed to various types of faults. Hence, on-line condition monitoring and fault diagnosis of PMSMs have become necessary. One of the most common PMSM faults is the stator winding fault. Due to the destructive character of this failure, it is necessary to use fault diagnostic methods that allow fault detection at its early stage. The article presents the results of experimental studies obtained from fast Fourier transform (FFT) and short-time Fourier transform (STFT) analyses of the stator phase current, stator phase current envelope and stator phase current space vector module. The superiority of the proposed method over the classical approach based on the stator current analysis using FFT is highlighted. The proposed solution is experimentally verified under various motor operating conditions. The application of STFT analysis discussed so far in the literature has been limited to the fault diagnosis of induction motors and the narrow range of the analysed motor operating conditions. Moreover, there are no works in the field of motor diagnostics dealing with STFT analysis for stator windings based on the stator current envelope and the stator current space vector module.
EN
Currently, in transport systems, as part of the main and auxiliary equipment, a large number of induction motors with a squirrel-cage rotor of different capacities are used. Their wide application in the transport industry is associated with the main advantages over other types of machines – a fairly high reliability, low cost and ease of maintenance. However, during the operation of these motors, a number of malfunctions can occur that affect the deterioration of the performance of the entire drive, the accuracy of its functions, or accelerate an emergency stop. To ensure proper control of the technical condition of electric motors, modern diagnostic systems are required that operate in real-time and operational loading mode with the transmission of data on the instantaneous state of the main control elements. The paper proposes a block diagram of the diagnostic built-in system and developed a modular unit for it to set the type and degree of the most complex damage - inter-turn short circuit in the stator winding.
EN
Various approaches have been proposed to monitor the state of machines by intelligent techniques such as the neural network, fuzzy logic, neuro-fuzzy, pattern recognition. However, the use of LS-SVM. This article presents an automatic computerized system for the diagnosis and the monitoring of faults between turns of the stator in IM applying the LS-SVM least square support vector machine. in this study for the detection of short circuit faults in the stator winding of the induction motor. Since it requires a mathematical model suitable for modelling defects, a defective IM model is presented. The proposed method uses the stator current as input and at the output decides the state of the motor, indicating the severity of the short-circuit fault.
5
EN
The article contains the results of research within the project to apply unipolar (axial) flux to obtain diagnostic signals carrying the information of: electrical asymmetries of machinery (inter-turn stator short-circuits, cage damages); rotational speed of the rotor and load torque. Inter-turn stator short-circuits can be detected both at starting process time (when they appear most often), as well as in steady states. Detection of rotor cage defects in steady states has a character of a comparative study, and over time, as the defects develop. For standard drives that are powered from the network and work in open systems, by measuring the voltage following a unipolar flux, it is possible to make measurement and recording of motor speed, which usually is almost never provided under industrial conditions. The study shows that a simple in its construction, cheap coil can be a very useful diagnostic tool. The measurements were carried out at the laboratory and motor workplace in the power plant, while in the test station, during the loading, characteristics illustrating the dependence of the torque on the axial flux and on the rotational speed were obtained. A way of using a single measurement to estimate the torque has been proposed. The method is relatively simple to implement and allows for a fully non-invasive determination of the load torque.
EN
The article presents the results of research on the use of an axial flux in the diagnostics of induction motor stator winding fed by a frequency converter. Voltage signal waveforms proportional to the axial flux were recorded during motor operation under various conditions and were analyzed with regard to the detection of stator winding short circuits. The taps of the selected coil turns of stator phases were introduced into the tested motor, which allowed to physical modelling inter-turn short circuits. The structure and operation of the computer system used to monitor the state of induction motor windings were discussed. The developed diagnostic system was made in the National Instruments LabVIEW environment. The analysis of faults of the axial flux was made in the detection of induction motor stator winding. The results of experimental research conducted using the developed diagnostic system have also been presented.
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