Génie électrique
A new time–frequency method for identificationand classification of ball bearing faults
In order to fault diagnosis of ball bearing that is one of the most critical components ofrotating machinery, this paper presents a time–frequency procedure incorporating a newfeature extraction step that combines the classical wavelet packet decomposition energydistribution technique and a new feature extraction technique based on the selection ofthe most impulsive frequency bands. In the proposed procedure, firstly, as a pre-processing step, the most impulsive frequency bands are selected at different bearing conditionsusing a combination between Fast-Fourier-Transform FFT and Short-Frequency Energy SFEalgorithms. Secondly, once the most impulsive frequency bands are selected, the measured machinery vibration signals are decomposed into different frequency sub-bands byusing discrete Wavelet Packet Decomposition WPD technique to maximize the detectionof their frequency contents and subsequently the most useful sub-bands are representedin the time-frequency domain by using Short Time Fourier transform STFT algorithm forknowing exactly what the frequency components presented in those frequency sub-bandsare. Once the proposed feature vector is obtained, three feature dimensionality reductiontechniques are employed using Linear Discriminant Analysis LDA, a feedback wrappermethod and Locality Sensitive Discriminant Analysis LSDA. Lastly, the Adaptive NeuroFuzzy Inference System ANFIS algorithm is used for instantaneous identification andclassification of bearing faults. In order to evaluate the performances of the proposedmethod, different testing data set to the trained ANFIS model by using different conditionsof healthy and faulty bearings under various load levels, fault severities and rotatingspeed. The conclusion resulting from this paper is highlighted by experimental resultswhich prove that the proposed method can serve as an intelligent bearing fault diagnosissystem. Voir les détails
Mots clés : Vibration signal processing Bearing fault diagnosis Bearing faults LDA, LSDA, ANFIS, WPD
Static eccentricity fault modeling in permanent-magnet synchronous motors
In this paper, a model based on the finite element analysis has been developed for healthy and eccentric PMSM. The proposed model is analyzed by time stepping Finite element method. The electromagnetic field distribution, air-gap magnetic flux density and the leakage inductances under healthy and eccentric rotor have been calculated. Meanwhile, the MCSA of the healthy and faulty PMSM is inspected under various static eccentricity levels. Voir les détails
Mots clés : PMSM, Finite Element Method, diagnosis, Static Eccentricity, Spectral analysis
Corrosive effects of the electromagnetic induction caused by the high voltage power lines on buried X70 steel pipelines
This paper diagnoses the corrosive effects of the electromagnetic induction caused by double circuit high voltage power lines (HVPL) on the buried X70 steel pipelines. To achieve this objective, firstly the electromagnetic interference between the double circuit HVPL and the X70 steel pipeline (the distribution of the magnetic field and the induced AC current densities in the buried X70 steel pipeline) and the factors affecting this interference such as the vertical distance between the double circuit HVPL and the X70 steel pipeline, and the conductor phase sequence orientation were studied. Then, electrochemical measurements were used to characterize the corrosion polarization properties of X70 steel in simulated soil at various AC current densities. The results show that with an increase in the AC current density, the corrosion rate of the X70 steel increased, indicating that the induced AC current density has accelerated the corrosion degree of X70 steel, by comparison with that in the absence of the AC current density. We can conclude from these results that the electromagnetic induction caused by the double circuit high voltage power lines affects the electrochemical characteristic of the X70 steel pipeline and accelerates the corrosion of the pipeline. Voir les détails
Mots clés : Electromagnetic induction, high voltage power line, induced AC current density, X70 steel pipeline, corrosion, Finite element method.
Diagnosis of AC corrosion on the buried pipeline due to the high voltage power line
This paper studies the electromagnetic effect of the high voltage power line on the X70 Steel pipeline and the factors affecting this interference. The induced voltage onto the pipeline was calculated for different separation distance between conductors, the existence of the earth wire, separation distance between transmission line and pipeline and the parallelism length. The induced AC current density was calculated function to the induced voltage, the soil resistivity, and the holiday diameter. The electrochemical characters of the X70 steel with and without influence of the alternating currents were studied in simulated soil solution. The results indicate that the AC density accelerate the corrosion degree of X70 steel in simulated soil solution comparing with that in the absence of the AC density. Voir les détails
Mots clés : Power lines, interference, induced voltage, induced current density, AC corrosion.
THE CONTRIBUTION OF DIRECT TORQUE CONTROL WITH APPLICATION OFFUZZY LOGIC ON THE PERFORMANCE OF A MULTI-LEVEL INVERTER FED INDUCTION MACHINEWITH A FAULT TOLERANCE
Today it is possible to obtain induction machine performances similar to those of dc machines through the mastering of power electronics and control.Moreover, there are new methods of control for sensorless speed traction-type applications already studied particularly those related to the Direct Torque Control technique (DTC). This study consists at optimizing the three-level DTC algorithm fed from an NPC structure multilevel inverter with fault tolerant using are the configurable redundant spare arm to increase the average value of the torque. The results obtained in the DTC are further improved by applying the technique of fuzzy logic Voir les détails
Mots clés : Multilevel Inverter, DTC, NPC, Fault tolerance, Fuzzy logic.
APPLICATION DE TECHNIQUE DE L'INTELLIGENCE ARTIFICIEL (R-N) POUR LA CONTROLE DIRECTE DE COUPLE D'UNE MAS ALIMENTEE PAR DES ONDULEURS MULTINIVEAUX.
Dans cet article nous présentons les résultats de simulation de la régulation de vitesse d’une machine asynchrone commandée par contrôle direct de couple par application de technique de l'intelligence artificiel comme réseau de neurone (DTNC). Comparativement à la commande directe du couple (DTC) à 12 secteurs . L’analyse des résultats montre de bonnes performances pour la vitesse et une réduction des fluctuations au niveau du couple et du flux dans la stratégie proposée pour le contrôle de l’association onduleur à trois niveaux machine asynchrone. Ce modèle est ensuite simulé sur Matlab/Simulink. Voir les détails
Mots clés : machine asynchrone, contrôle directe de couple (DTC), DTNC, onduleur à trois niveaux.
LA CONTRIBUTION DU CONTROLE DIRECTE DE COUPLE D'UNE MAS ALIMENTEE PAR DES ONDULEURS MULTINIVEAUX EN APPLIQUANT DE L'INTELLEGENCE ARTIFICIEL (LOGIQUE FLOUE).
Aujourd'hui, il est possible d'obtenir des machines asynchrones aussi performantes que celles à courant continue grâce à la maitrise de l’électronique de puissance et de commande. Par ailleurs, il existe de nouvelles méthodes de commande destinées aux applications type traction sans capteur de vitesse déjà étudiées s'agissant notamment de la technique de contrôle direct du couple (DTC). Cette étude consiste à l'optimisation de l’algorithme DTC à trois niveaux, en appliquant plusieurs approches pendant la conception des tables de commutations afin d’améliorer les résultats classiques notamment la réduction d’ondulation du couple. Les résultats obtenus dans la DTC classique sont encore améliorés en appliquant la technique de la logique floue. Voir les détails
Mots clés : machine asynchrone, contrôle directe de couple (DTC), onduleur à trois niveaux, logique floue
A COMPARATIVE STUDY OF TWO TYPES OF DTC WITH APPLICATION OFARTIFICIAL INTELLIGENCE: FUZZY LOGIC AND NEURON NETWORK ON THEPERFORMANCE OF A MULTI-LEVEL INVERTER FED INDUCTION MACHINE
We present in this paper the simulation results of the speed control of a 3 levels inverter-fed induction machine controlled by the Direct Torque Control with an application of artificial intelligence techniques both the fuzzy logic(DTC_FL) and the neural network (DTC_NN). A comparative study of these two techniques is also presented to illustrate the merits of each of the techniques on the performance of the 3-levels inverter-/induction machine set. Voir les détails
Mots clés : Induction machine, 3-Levels Inverter, Direct Torque Control (DTC), DTC_FL, DTC_NN
A comparative Study of Two Types of DTC With Application of Artificial Intelligence: Fuzzy Logic and Neuron Network on the Performance of a Multi-level Inverter Fed Induction Machine
We present in this paper the simulation results of the speed control of a 3 levels inverter-fed induction machine controlled by the Direct Torque Control with application of artificial intelligence techniques both the fuzzy logic(DTC_FL) and the neural network (DTC_NN). A comparative study of these two techniques is also presented to illustrate the merits of each of the techniques on the performance of the 3-levels inverter-/induction machine set. Voir les détails
Mots clés : Induction machine, 3-Levels Inverter, Direct Torque Control (DTC), DTC_FL, DTC_NN
A summary of Vibration analysis techniques forfault detection and diagnosis in bearing
Bearing is one of the most critical components ofrotating machinery .They are employed to support and rotate theshafts in rotating machinery. Therefore; any fault in the bearingscan lead to losses on the level of production and equipments aswell as the creation of an unsafe working environment forhumans. For that reason, the bearing fault diagnosis has receivedconsiderable attention from the research and engineeringcommunities in recent years. The purpose of this study is toreview the Vibration analysis techniques and explore theircapabilities, advantages and disadvantage in monitoring rollingelement bearings. Voir les détails
Mots clés : Vibration analysis, bearing Fault diagnosis, Fast Fourier Transform (FFT), Envelope Analysis (EA), Short Time Fourier Transform (STFT), Empirical Mode Decomposition (EMD)