Squirrel-cage Asynchronous Motor Research Articles

A novel deep convolutional neural network and its application to fault diagnosis of the squirrel-cage asynchronous motor under noisy environment

The intelligent classification achieved through the utilization of deep learning networks, which possess the capability to automatically extract essential features from data, has garnered significant attention within the domain of fault diagnosis research. Nevertheless, within the industrial production process, the data collected inevitably suffers from noise contamination, thereby adversely affecting the network’s diagnostic results. To enhance the denoising prowess and mitigate the risks associated with overfitting in deep learning networks, this paper introduces the input gate structure of long short-term memory and an attention module into the convolutional neural network to propose a novel architecture known as the gate convolutional attention neural network (gate-CANN), which subsequently finds application in the domain of squirrel-cage asynchronous motor fault diagnosis. Firstly, the sensor-acquired time domain vibration undergo conversion into two-dimensional time–frequency images through the employment of continuous wavelet transform (CWT). Subsequently, the CWT images in two directions are put into gate-CANN for feature extraction, respectively. Finally, feature fusion and fault diagnosis are achieved in the end of network. To validate the effectiveness of the proposed method, it undergoes verification using the fault diagnosis testbed specific to squirrel cage asynchronous motors. The obtained results demonstrate that, in comparison to alternative diagnostic methods, the proposed approach exhibits superior capabilities in terms of noise resistance and generalization.

Indirect Space Vector Modeling of Asynchronous Motor for High-Speed Electric Vehicle Propulsion

This paper presents a high performance squirrel-cage asynchronous motor (ASM) drive, proposed for high-speed electric vehicle (EV) propulsion. This is an indirect space vector control (IDSVC) scheme in the rotor flux frame of reference, in which the modeling is based on synchronously rotating coordinate system transformation. Space vector pulse width modulation (SVPWM) inverter fetches the controlled stator direct and quadrature axis responses from the speed and current controllers and supply necessary voltages to stator of ASM. The output voltage waveforms of SVPWM inverter are not sinusoidal in nature, which allows undesired harmonics at high frequency of operation. This due to inconsistent switching frequency. A second-order low-pass (SOLP) RLC filter with Butterworth approximation and was designed and connected in series with SVPWM inverter to grab harmonic free speed and torque profile during high speed operations. Similarly, another SOLP with a quality factor equal to 2 is designed and speed profiles of both filters are compared. The system is developed and simulated in MATLAB/SIMULINK to observe the speed and torque tracking capabilities. Simulation results show that the performance of drive under steady and dynamic states were good with Butterworth filter approximation with robust IDSVC scheme adopted over wide range speed-drive curve.

Comparison between PI-DTC-SPWM and fuzzy logic for a sensorless asynchronous motor drive

Currently, asynchronous cage motors are among the most commonly requested machines accentuated by their extension to the field of electric vehicles. Therefore, the development of robust and sophisticated controls for this machine is of significant interest. Artificial intelligence control techniques, such as fuzzy logic, are at the forefront of recent research. However, their design becomes much more complicated for a motor via a multilevel inverter. The main purpose of this paper is to show that it is possible to achieve fuzzy logic control of a squirrel cage asynchronous motor supplied via the usual two-level inverter. This is achieved, by adopting a DTC strategy based on a sinusoidal PWM with multilevel inverter. It employs a feedback information estimator with dual structure between the sliding mode observer at low speed and the model reference adaptive system in sliding mode at high speed. For both installations, speed is regulated using a sliding mode controller.

Applying sliding mode technique for the nonlinear DTC-SPWM control strategy of sensorless squirrel cage asynchronous motor

The classical Direct Torque Control has been elaborated to achieve advanced performance of asynchronous motor, especially in speed behaviours. Due to its high level of ripples and variable frequency, several modifications have been proposed to improve it. In this paper, two modified strategies of the direct torque control dedicated to asynchronous motors are presented, the first method is based on the sinusoidal pulse width modulation and PI regulators for regulating torque, speed and stator flux. The second is based on sliding mode control where the principal purpose is to force the system’s trajectory to slide along the switching surface by a well-defined control law. Furthermore, this paper aims to design two observers; the first will be evaluated by the direct calculation method and the second will be formed by sliding mode. These observers can improve control performance while eliminating mechanical sensors and thereby increasing the overall system’s reliability.

3 Fazlı Asenkron Motorun Farklı Çalışma Koşulları Altındaki Tepkisinin Vektör Kontrol Tekniği ile Analizi

Asenkron motorlar yaygın kullanım alanlarına sahiptir. Tasarımları güvenilir ve ucuz olmasıyla birlikte kontrolü zordur. Bu nedenle kontrol sistemini basitleştirmek amacıyla çeşitli sistemler geliştirilmiştir. Bu sistemlerden birisi de Vektör Kontrol (Alan Yönlendirmeli Kontrol) dür. Bu çalışmada 3 fazlı sincap kafesli bir asenkron motorun doğrudan, kapalı çevrim, vektör kontrol tasarımı Matlab/Simulink ortamında yapılmıştır. Belirlenen sabit bir referans hıza ulaşma durumu, belirli aralıklarla değişen referans hızlara ulaşma durumu, devreye yük alındığı durumda daha önce belirlenmiş referans hıza tekrar ulaşma durumu gibi durumlar incelenmiş ve asenkron motorun referans hızlara rahatlıkla ulaştığı görülmüştür. Tasarımın doğruluğu ve işe yararlığı ispatlanmıştır.

Broken Rotor Bar Fault Diagnosis of Squirrel Cage Asynchronous Motor Based on Vibration Spectrum and Current Spectrum

In this paper, the vibration spectrum and current spectrum analysis technology are used to accurately diagnose the broken rotor bar fault of the slurry circulating pump motor. This paper elaborates on the mechanism of broken rotor bar fault, deduces the common motor pole pass frequency calculation formula, introduces the specific diagnosis process and disintegration of the broken slurry circulating pump motor’s rotor bar breakage fault. The cause of the fault is analyzed, and this type of the fault diagnosis method is also summarized.

Діагностування обмоток статора асинхронного двигуна з використанням моделювання на основі годографа вектора Парка

Despite the large number of methods for monitoring the condition of the stator windings of squirrel-cage induction motors, the issue of improving and developing diagnostic equipment with a high degree of reliability that meets modern operational requirements remains unresolved. The available methods take into account only the limiting or permissible states of the winding parameters, which do not allow us to evaluate defects at an early stage of their development. An especially hard-to-diagnose damage requiring further research is the interturn short circuit in the phase of the stator winding. The paper considers a method for diagnosing interturn closure of a stator winding using mathematical modeling based on the hodograph of the Park vector. For this purpose, a mathematical model of an induction motor with established adequacy to real processes was chosen, with which the computing unit of the Park vector was used. As a result of modeling, using an example of an asynchronous motor model AIR with a power of 11 kW, the hodographs of the Park vector for a stator without defects in nominal mode were obtained; as a result of interturn closure with complex phase resistance reduced to 80% in nominal mode and in idle mode. It is established that the considered method of applying the simulation model of a squirrel-cage asynchronous motor based on the hodograph of the Park vector allows modeling defects in the stator windings, studying their effect on motor operation, and also diagnosing the degree of defects that occur in the stator. When applying the method of spectral analysis of the hodograph of the Park vector to diagnose interturn closure faults of the stator winding, it is necessary to take into account the influence on the result of the parameters of the supply network, the nature of the load, the influence of external electromagnetic fields, transient processes in the motor, etc., accounting for which requires additional research. The possibility of using method of the hodograph of the Park vector for diagnostics of windings of induction motors remotely, without stopping the operation of the motor and when used in fully automated diagnostic systems, makes this method the most promising for further development and use.

The Analysis of the Digital AC Motor Speed Control System Operation

Abstract The article presents the analysis of the automatic alternate current motor control system, carried out by the author. The automatic control system has been implemented on the existing laboratory stand, containing: the squirrel-cage asynchronous motor and the frequency inverter. The existing stand imposed one of the available speed control methods for the motor and the necessity of the appropriate elements selection for the automatic control system [1]. The automatic control system has been designed and created as the constant value follow-up digital controller. To designate the parameters of the control object the unit step method of was used. After registering the output changes caused by the unit step, the characteristic curve was received that allowed to determine the alternative transmittance of the control object which, in turn, has made possible to find the appropriate controller settings.

NEURAL NETWORKS APPLICATION FOR MECHANICAL PARAMETERS IDENTIFICATION OF ASYNCHRONOUS MOTOR

A method for identification of mechanical parameters of asynchronous motor is presented in this paper. The identification method is based on the use of our knowledge about the system. This paper clarifies the method using the example of identifying mechanical parameters of the three-phase squirrel-cage asynchronous motor. Model of mechanical subsystem of the motor is presented as well as results of simulation. The special neural network is used as identification model and its adaptation is based on the gradient descent method. Parameters of mechanical subsystem are derived from the values of synaptic weights of the neural identification model after its adaptation. Deviation of identified mechanical parameters in case moment of inertia was up to 0.03\% and in case of load torque was 1.45 \% of real values.

Study into overcurrent protection technology for mine asynchronous motor

In the running of mine motor, it is extremely vulnerable to overcurrent faults such as short-phase failure or short circuit, so the study in overcurrent protection for asynchronous motor is of great significance. The characteristics of overcurrent failure for mine asynchronous motor are analyzed, a mathematical model of overcurrent fault is established and the overcurrent protection principle is analyzed in this paper. Due to the malfunction defect of traditional symmetrical short-circuit protection in the starting of large motor, a new protection scheme is proposed, which is to adopt the phase-sensitive protection based on power factor detection and short-circuit fault detection scheme based on wavelet transform Mallat algorithm. Meanwhile, a method of asymmetrical fault protection based on negative-sequence current detection is proposed in the paper. In addition, overcurrent protection technology is applied to the overcurrent protection of mine squirrel cage asynchronous motor, of which the effectiveness and the practicality have been verified.

The Boot Method Analysis of Three-Phase Asynchronous Motor

The boot method of three wound-rotor asynchronous motors and three-phase squirrel-cage asynchronous motor are described; As to reduce the start current and to increase the starting torque, the principle of all kinds of startup methods are analyzed; the advantages and disadvantages of various starting methods are evaluated; Development directions of modern motor startup are pointed out.

Breaks Strip Breakdown with the Parameter Identification Law Diagnosis Mouse Cage Asynchronous Motor Rotor

According to the three-phase squirrel-cage asynchronous motor rotor broken bar fault, presented with parameters identification method of asynchronous motor parameter identification to monitoring and diagnosis of rotor resistance variation of rotor bar breaking principle. Choose a three-phase squirrel-cage asynchronous motor in three working points of experiments, results show that the method is correct and feasible. This method is based on the three-phase squirrel-cage asynchronous motor steady state model parameter equation, using the method of least squares identification parameters, and consider the effects of temperature on the parameters, by the parameter variation in diagnosis of broken rotor bar fault. Advantages of simple scientific method, this method can also be used in conjunction with other methods and, on the three-phase squirrel-cage asynchronous motor rotor has no fault diagnosis.

An online broken bar fault detection method and its application to squirrel-cage asynchronous motors

In this paper, an improved online stator current analysis method is proposed for detecting the rotor broken bar fault of three-phase squirrel-cage asynchronous motors. With the rapid development of the advanced digital filtering technique (such as ZOOM-FFT) and the rotor slot harmonics (RSH) techniques for slip measurement, it is possible to accurately estimate a motor’s slip rate from the precise measurements of the harmonic components of a rotor and the power supply frequency. This enables us to find the characteristic spectrum of a bar-broken rotor from the stator current spectrum. We proposed an online algorithm to detect the motor broken bar fault by localising and checking the existence of the fault-related characteristic spectrum. The proposed method overcomes the drawback of traditional current spectral analysis approaches. In particular, this paper addresses the problem that the side lobe spectral components are covered by the fundamental frequency and noises. This method has been validated in our experiment with a 30 kW three-phase induction motor. The experiment results show that the proposed method is able to detect small broken rotor bar fault with good application perspective.

Design of Intelligent Explosion-Proof Electromagnetic Starting Reactor Based on PIC16F887

According to high-voltage squirrel-cage AC asynchronous motor using string reactor to reduce voltage starting,there are some shortcomings such as circuit complexity, operation and maintenance trouble, the unfavorable to maintain and update and so on. Design of an intelligent explosion-proof electromagnetic starting reactor based on PIC16F887 microcontroller is proposed, this reactor has time type, current type, time-current starting type which can be set and it has temperature detection protection function in the starting process. After starting completion, it also has the bypass electrical locking function which can real-time monitor the current, voltage and temperature signals to realize intelligent. Using the reactor of controller already has been applied rated voltage 10kV, rated power 1600kW fan commissioning in a coal mine, the test results indicate that this reactor controls current smoothly in the starting process, and has reliable starting performance, easy operation, and high degree of intelligence.

Time-stepping finite element analysis on the influence of skewed rotors and different skew angles on the losses of squirrel cage asynchronous motors

To study the influence of skewed rotors and different skew angles on the losses of squirrel cage asynchronous motors, a 5.5-kW motor was taken as an example and the multi-sliced field-circuit coupled time stepping finite element method (T-S FEM) was used to analyze the axially non-uniform fundamental and harmonic field distribution characteristics at typical locations in the stator and rotor cores. The major conclusions are: firstly the skewed rotor exhibits a decrease in the harmonic copper losses caused by slot harmonic currents in the stator winding and rotor bars. Secondly, the skewed rotor shifts the non-uniform distribution of field in the axial direction, which leads to more severe saturation and an increase in iron losses. The heavier the load, the more pronounced the increase in iron losses. Furthermore, the influences of different skew angles on motor losses are studied systematically, with skew angles from 0.5 to 1.5 stator tooth pitch. It is found that the lowest total loss occurs at 0.8 stator tooth pitch, and the slot harmonics can be decreased effectively.

Speed estimation of vector controlled squirrel cage asynchronous motor with artificial neural networks

In this paper, the artificial neural networks as a sensorless speed estimator in indirect vector controlled squirrel cage asynchronous motor control are defined. High dynamic performance power semi conductors obtainable from direct current motors can also be obtained from asynchronous motor through developments in digital signal processors (DSP) and control techniques. With using of field diverting control in asynchronous motors, the flux and moment can be controlled independently. The process of estimating the speed information required in control of vector controlled asynchronous motor without sensors has been obtained with artificial neural networks (ANN) in this study. By examining the data obtained from the experimental study concluded on the DSP application circuit, the validity and high performance of the ANN speed estimator on real-time speed estimation has been demonstrated.

The Mechanical Transient Process at Asynchronous Motor Oscillating Mode

The Mechanical Transient Process at Asynchronous Motor Oscillating ModeThe research object is squirrel-cage asynchronous motor connected to single-phase sinusoidal. There are shown, that by connecting to the stator windings a certain sequence of half-period positive and negative voltage, a motor rotor is rotated, but three times slower than in the three-phase mode. Changing the connecting sequence of positive and negative half-period voltage to stator windings, motor can work in various oscillating modes. It is tested experimentally. The mechanical transient processes had been researched in rotation and oscillating modes.

Finite Element Thermal Modeling of an Induction Motor

In the present paper, the authors implement a steady state finite element analysis of the heat field inside an induction motor. The tested machine is a standard squirrel cage asynchronous motor of Totally Enclosed Fan Cooled "TEFC" design. The thermal calculation is done in a 2D radial view that represents an angular space of 12.857 ° (rotor tooth pitch) of the considered machine. To validate the proposed thermal model, the temperature measurements at different points within the motor were obtained using 16 sensors (CTN thermistors) placed inside the test motor. The simulated temperatures so obtained are in good agreement with the measured ones, and the 2D study seems to be appropriate to characterize the heating of the active parts of the machine.

Inverter-Fed Asynchronous Motors for Traction Systems

Publisher Summary Variable-frequency inverter-fed asynchronous motor constitutes, in the field of electric traction, an effective option to traditional d.c. motor. The success of this equipment is connected to the advantages the squirrel cage asynchronous motor may provide lower weight and small dimensions, higher power at high speed, less maintenance requirements, higher mechanical rotor strength, lower cost, and greater travelling comfort and is a direct consequence of the enormous progress obtained by power electronics during recent years, both as concerns costs and reliability. Rotor temperature measurement is possible in different positions. Thermo-resistors are employed and the signal is transferred from the rotating part by a collector. The voltages, currents, and couples waveforms may be acquired both under steady and transient state conditions, on a minicomputer that may be connected contemporaneously with a maximum of 8 analogical and 4 (16 bit) digital channels. It is, thus, possible to obtain experimentally both instant values and harmonic analysis first disc storing and them printing or plotting.

Double squirrel cage asynchronous motors for speed reversing drives

This paper is a further step in the study of induction machines supplied with limited current at variable frequency. We outline the performances of the double squirrel cage asynchronous motors which can be used in drives requiring continuous starting and braking operations with or without speed reversing. We show the possibility of feeding the machine in motor and braking operations with voltage versus frequency laws so that the armature current is equal to the limit value for the breakdown slips at different frequencies. Last of all, we outline the influence of the electrical parameters of the motor in the steady state behaviour at variable frequency, with special reference to the driving torque - speed characteristics and to the amplitude of the alternative torques. Als weitere Fntwicklung der Beobachtungen über die mit wechselnden Frequenz und Spannung und begrenztem Strom gespeiste Drehfeldmaschinen werden im folgenden die Betriebseigenschaften von Doppelkafigasynchron-motoren untersucht, zur Anwendung für Antrieb, die aufeinanderfolgende Anläufe und Bremsungen unter oder ohne Geschwindigkeitsumkehrungen erfordern. Es wird gezeigt, daβ die Maschine in Betrieb als Motor sowie als Bremse nach Spannung-Frequenz-Gesetzen zu speisen ist, sodaβ der Anker-strom dem Grenzstrom entsprechend den Kippenschüpfen unter verschiedenen Frequenzen gleich ist; zudem wird der Einfluβ von elektrischen Para metern des Motors über dessen stationäre Betriebseigenschaften mit wechselnder Frequenz unterstrichen, besonders bezüglich der Eigenschaften 'Drehmoment - Geschwindigkeit' sowie der Amplitude der Pendelmomente.