Liste des communications
Eccentricity Fault Diagnosis based on Wavelet Transform and Neuro-Fuzzy Inference System in Doubly-fed Induction Generator
he development of wind turbine system is becoming very influential, in conditions of power qualityand very interesting for ecological protection. However, their potential is considerable in the world, thewind energy sources have drawn more and more attention all over the world recent years to improve theserious environment problems and deal with the shortage of fossil fuels in recent years [1]. The doubly-fedinduction generator (DFIG) is one of essential part of wind turbine system and has dominated in the field ofelectromechanical energy conversion system because of robustness and low cost [2]. So, for a substantialprofit, the diagnosis should be properly developed to ensure a production system more make safe.Production systems must be provided with reliable protection systems as any failure can lead to inevitabledamage [3].The occurrence of different faults can be completely in damage this machine type and inevitably cause theprocess to stop, resulting in loss of production consequently [4]. Therefore, it is necessary to develop amodel machine allow to detect the presence of the faults.Wind turbine is prone many failures and because of their size and localization, it is very costly to repair oremplace their component. In generally, mechanical faults are the most encountered in wind turbinessystems at the gearbox. These faults can occur at the level of ball, inner and outer race bearings, andflanges of the machine shaft. In scientific research tasks shows that rotor faults are more frequentbreakdowns, [5, 6]. In this paper we are interested to study the rotor eccentricity faults types [7].The DFIG in this type of faults can be subjected to counteract between the center of rotation of the shaftand the center of the rotor resulting the oscillations in the electromagnetic torque, uneven distribution of thecurrents in the rotor and the unbalance of stator current. This phenomenon is called static or dynamiceccentricity, and both at the same time creates the fault mixed eccentricity, whose origin may be related toincorrect positioning of the bearings during assembly or bearing failure [8, 9].Eccentricity Fault Diagnosis based on WaveletTransform and Neuro-Fuzzy Inference System inDoubly-fed Induction GeneratorMerabet. HichemResearch Center in Industrial Technologies (CRTI) P.O.Box 64, Cheraga, Algeria.h.merabet@csc.dzBahi. TaharElectrical Department, University of Annaba, Algeriatbahi@hotmail.comBedoud. khouloudResearch Center in Industrial Technologies (CRTI) P.O.Box 64, Cheraga, Algeria.k.bedoud@csc.dzDrici. DjalelResearch Center in Industrial Technologies (CRTI)P.O. Box 64, Cheraga, Algeria.d.drissi@csc.dzTSeveral methods of diagnosis are based on spectral analysis of the electromagnetic quantities, using themagnetic flux, stator current and the neutral voltage vibration signal analysis and especially the statorcurrent which requires only a current sensor [10, 11]. Therefore most of the recent research has bennedirected towards non-invasive techniques such as stator current and vibration signal analysis, motorsignature analysis with wavelet transform, courant envelope, Artificial Intelligence such as NeuralNetwork, Fuzzy Logic and Fuzzy Neural Network. The analysis of the stator currents in the waveletdomain remains the most commonly used because the spectrum results contains a source of information onthe majority of electrical and/or mechanical faults and magnetic properties can appear in the machine [12,13].The artificial intelligences based on fuzzy logic system inference, artificial neural network (ANN) orcombined structure techniques of artificial neural fuzzy interference system (ANFIS) are widely used in thenew monitoring[14, 15].Therefore, in order to increase the efficiency and the reliability of the monitoring in the field of the(DFIG) supervision, the proposed technique is based on wavelet transform and Neuro-Fuzzy inferencesystem (ANFIS).In this paper, the investment interest in wind turbine conversion system based on DFIG is presented.Then, we focus on the study of their designs and the development of a global model for doubly-fedgenerator in case of rotor eccentricity faults.Finally, in order to validate the considered method, the proposed model has been simulated and validatedby numerical simulations using MATLAB/Simulink. Voir les détails
Mots clés : eccentricity, fault, diagnosis, wavelet, ANFIS, DFIG
The corrosion resistance ofsupermartensitic steels compared to martensitic steels in different corrosion media
The supermartensitic stainless steels deduced from the refinement of the compositionof martensitic steels, have a low carbon content with 13% of chromium, 5% of nickel and 2%of molybdenum, this new generation of steel has an improved ductility with a good resistancemechanical and excellent resistance to corrosion. In this work, a comparative study of thecorrosion behavior of these two stainless steels in different aggressive chlorinated andsulphurized media was carried out. Stationary (polarization curves) and transient(electrochemical impedance) electrochemical methods have been applied. The rate ofcorrosion as a function of time was determined by the mass loss method and thecharacterization of the surface condition was studied by optical microscopy. Two types ofcorrosion were observed: uniform corrosion in which the half-reactions are homogeneouslydistributed in 0.5M H2SO4, followed by localized corrosion observed in 0.5M NaCl for bothsteels. According to the polarization curves, the corrosion potential differs betweenmartensitic steel and supermartensitic steel where it has a higher potential with -0.342 V / Ag/ AgCl in 0.5M H2SO4 and -0.339 V / Ag / AgCl in 0.5M NaCl. In parallel, the polarizationresistance given by EIS shows that in both media, supermartensitic steel is more resistant thanmartensitic steel where it has an Rp equal to 7200 Ohm in 0.5M H2SO4 and 8340 Ohm 0.5MNaCl. These results are confirmed by the optical microscope microstructure. Voir les détails
Mots clés : corrosion, martensitique stainless steel, supermartensitique stainless steel
Direct Power Control of DFIG Used in Wind EnergyConversion System
The problems caused by traditional systems on the environment of energy production havesucceeded, in the immediate, the utilization the renewable energies for to preserve theenvironment and to satisfy the energy. So, thanks to the encouragement of governments andthe global orientations, the development of wind energy has grown significantly due to thediversity of exploitable areas and to the relatively attractive costs. Therefore, the wind energyis becoming one of the most important renewable energy sources. Indeed, variable speedWind Energy Conversion System (WECS) have become the industry standard because oftheir advantages over fixed speed ones such as improved energy capture, better power quality.The WECS described in this work is show by figure 1. He includes the wind turbine, gearbox,DFIG, and back-to-back converters whereas the stator winding is fed by back-to-backbidirectional converter. In this system, the wind energy is transmitted Through theturbine to the three-phase DFIG. This energy is transmitted directly through a bridgerectifier and inverter to the electrical network. Voir les détails
Mots clés : Wind energy conversion system; Doubly Fed Induction Generator; Maximum power point tracking; Simulation
Etude du pouvoir d’inhibition des terres rares contre lacorrosion des aciers bas carbone
Afin de limiter la dégradation des aciers en service, des traitements de surface sontappliqués .L’association de différentes couches permet de protéger les matériaux contre lacorrosion de manière durable. Les composés à base de chrome hexavalent sont depuistoujours les plus utilisés dans le secteur aéronautique, car ils sont simples à mettre en oeuvre etsont reconnus comme étant les inhibiteurs les plus efficaces de la corrosion des aciers. Lesrécentes directives européennes précisent que l’utilisation des composés à base de chromehexavalent doit être réduite, voire supprimée, car ceux-ci ont été reconnus cancérigènes ettoxiques pour l’environnement. De nombreux travaux ont été réalisés ces dernières annéesmais, aujourd’hui, la plupart des solutions de substitution ne présentent pas le même niveaude performances que les procédés à base de chrome hexavalent. Un des traitements alternatifsde passivation utilise des oxydes de terres rares, notamment le cérium. L’utilisation ce derniercomme inhibiteur qui remplace le chrome hexavalent est caractérisé par la formation descouches minces est généralement associée à la formation d’oxydes ou d’hydroxydes decérium sur les sites cathodiques de la surface métallique. La caractérisation électrochimiquede ce procédé d’inhibition a été évaluée dans des milieux agressifs tels que NaCl 0.1 M,Na2SO4 0.1M et aussi une eau industrielle. Ainsi, la résistance à la corrosion obtenue surl’acier A 366 a été étudiée. Pour l’ensemble des échantillons, la durée de protection a étéévaluée grâce à la mesure de Ecorr. En parallèle, l’efficacité est suivie par la mesure de larésistance de polarisation, de la densité de courant de corrosion et aussi la spectroscopied’impédances électrochimique. En conclusion, les résultats des différentes techniquesélectrochimiques ont montré que le cérium peut très bien et avec une efficacité équivalenteremplacée le chrome hexavalent. Voir les détails
Mots clés : corrosion, chrome, cerium, impédance
Study of the resilience of a composite materialintended for the orthopedic prosthesis of a tibia
This approach is based on the mechanical characterization of a biomaterial which is an organiccomposite with a thermosetting polymer matrix reinforced with a glass fiber; this composite has beenproduced by a conventional casting method. Currently, composite polymer-matrix objects occupy animportant place in the aeronautics, automotive, medical industry etc……, for this purpose, we areinterested in the study of a mechanical property of a thermosetting polymer matrix compositereinforced with glass fiber, this composite is intended for the orthopedic prosthesis of a tibia, thisproperty called resilience. For so doing, we have realized a Charpy shock test on a sample of thepolymer matrix composite reinforced with a glass fiber for the orthopedic prosthesis of a tibia. Wehave also supported this study by a hardness test and microscopic characterization (SEM) to revealthe microstructure of the composite. Voir les détails
Mots clés : composite – mechanical property – resilience –hardness – microstructure
CHARACTERISTICS OF CALAMINE AND NATURAL PIGMENT FOR ANTI-RUST PAINTINGS
Abstract.This work has a double objective. On the one hand, the valorization of natural raw materials, in particular, the oolithic iron ores which do not find their use in iron and steel because of their high phosphorus content and on the other hand the recycling of steel by-products.. The ultimate goal is to synthesize an anti-corrosion paint.In this first part, we will study the characterization of these two components by their chemical analysis, their grinding (fineness) and their thermal analysis (TGA, DSC).Chemical analysis showed that the pigment contains 53.18% of total iron and gangue dominated by silica. Calamine in turn contains 73.83% of iron in the form of iron oxides (FeO, Fe3O4 and Fe2O3).Iron pigment is composed mainly of hematite with a little of goethite.Grinding tests showed that the scale is much more suitable for grinding than pigment. The granulometric analysis measured by a laser granulometer (Hydro 2000MU) gave us a volume distribution of the particles with a size between 0.7 and 32 microns for scale and between 0.6 and 40 microns for the pigment and Their specific areas are 1.6 and 1.5 m2 / g..Thermogravimetric analysis (TGA) and the thermal variation of flow (DSC) showed that the iron pigment loses weight with phase dissolution by consuming energy when the temperature increases. Scale gains weight by the formation of new phase with heat.Exploration picture by scanning electron microscope of red iron pigment shows a grain aggregate formed rounded over at least iron oxide and gangue. The analysis by EDS shows a predominance of iron with a relatively large matrix containing the four predominant oxides in the case of iron ore deposits. Chemical elements forming these four oxides are silicon, calcium, aluminum and magnesium.The observation scale milled for 5 min SEM showed a homogeneous structure composed of sizes of iron oxide grains and shapes ranging from 1 µm to 10 µm. Voir les détails
Mots clés : Pigment iron, scale (calamine), iron oxides, grinding, Simultaneous thermal analysis.
Investigation of Blade Diagnosis by Empirical Mode Decomposition
The bladed disk components are considered as the most common cause of failures in turbomachines. The failure of a single blade can potentially compromise the total integrity of the machine. The aim of this article is to detect the blade failures such as crack, deformations, fracture of blade and blade loss using vibration analysis. Many signal analysis methods are able to extract useful information from vibration data. Currently, the most of these methods use temporal analysis based on scalar indicators. However, these methods present some limitations. In the present work, we are interested to the vibration signal analysis by the Empirical Mode Decomposition (EMD) and Fast Fourier Transform (FFT). The EMD is one of the most important topics in digital signal processing, by using this method the measured signals are decomposed into Intrinsic Mode Functions (IMFs) and then the spectrum of some IMFs are generated. By using the real vibration measurements from a pilot scale, the obtained results show that Blade defects are detected successfully. Voir les détails
Mots clés : Turbomachinery, Blade faults, Scalar Indicators, EMD, FFT
Characterization and Microstructural of Hot Rolling Mill Scale
In the IMETAL-El Hadjar complex, during the steel manufacturing process, a significant amount of scale is produced onthe surface of slabs and billets of hot-rolled steel. In the various rolling mills, the quantity of scale produced is estimated to be about0.1% of the annual production of the steel complex. The quality of the thin steel sheet during the rolling process is affected by thebehavior of the iron oxide layers formed on their surfaces (scale).This amount of scale which is a fatal by-product of the forging and rolling processes can be reused in certain areas and applied byappropriate recycling techniques such as agglomeration of iron ores in the blast furnace as a raw material. This aspect of recycling istaken into consideration.The objective of this study is to identify the microstructural properties of the scale, using different analytical methods such as X-raydiffraction and scanning microscopy.Several samples were used for characterization of the locally produced scale.The analyzes of the results given by SEM showed that hematite and magnetite, the main phases present in the scale, are stacked inthin layers of a magnitude of the order of a micron meter. These phases of iron oxides are confirmed by the analysis of the spectragiven by the X-ray diffractometer.The presence of silicon in the scale is due to the covering powder used on the wall layers of the ladles. Voir les détails
Mots clés : mill scale, Oxidation, hot rolling, Microstructural properties, SEM, X-ray.
Characterization and Microstructural of HotRolling Mill Scale
In the IMETAL-El Hadjar complex, during the steel manufacturing process, a significant amount of scale is produced on the surface of slabs and billets of hot-rolled steel. In the various rolling mills, the quantity of scale produced is estimated to be about 0.1% of the annual production of the steel complex. The quality of the thin steel sheet during the rolling process is affected by the behavior of the iron oxide layers formed on their surfaces (scale).This amount of scale which is a fatal by-product of the forging and rolling processes can be reused in certain areas and applied by appropriate recycling techniques such as agglomeration of iron ores in the blast furnace as a raw material. This aspect of recycling is taken into consideration.The objective of this study is to identify the microstructural properties of the scale, using different analytical methods such as X-ray diffraction and scanning microscopy.Several samples were used for characterization of the locally produced scale.The analyzes of the results given by SEM showed that hematite and magnetite, the main phases present in the scale, are stacked in thin layers of a magnitude of the order of a micron meter. These phases of iron oxides are confirmed by the analysis of the spectra given by the X-ray diffractometer.The presence of silicon in the scale is due to the covering powder used on the wall layers of the ladles. Voir les détails
Mots clés : mill scale, Oxidation, hot rolling, Microstructural properties, SEM, X-ray
SYNTHEASE NOUVEAUX VERRES A BASE D’OXYDES D’ANTIMOINE Sb2O3-PbCl2-As2O3 / AgCl ET LEURS CARACTERISATIONS
Le développement rapide de la technologie photonique nécessite de plus en plus des matériaux efficaces adaptés aux appareils photoniques tels que les matériaux pour amplificateurs et lasers de forte puissance. L’amplification optique basée sur le principe de l’effet laser peut être obtenue dans des matrices cristallisées ou vitreuses grâce aux émissions radiatives des ions de terres rares. Les verres sont parmi les matrices intéressantes pour leur transparence dans une large région optique et pour leur aptitude à recevoir de grandes quantités d’ions de terres rares. Ils peuvent être utilisés comme matériaux infrarouge dans le domaine militaire, la chirurgie et la médecine aussi bien sous forme de fibres qu'à l'état d'échantillons massifs (lentilles, hublots, etc...). A cet effet, une nouvelle famille de verres stables d’oxydes et d’halogénures dans les systèmes ternaires Sb2O3-PbCl2-As2O3 et Sb2O3-PbCl2-AgCl a été mise au point avec une pureté dépassant 98%. Plusieurs caractérisations ont été réalisées sur deux systèmes ternaires à savoir l’analyse thermique différentielle, la méthode de la poussée d’Archimède, la microindentation pour la détermination des propriétés élastiques des composants, les Ultra-violets et infra rouge pour l’obtention des propriétés optiques. Les résultats obtenus par la DSC (Differential Scanning Calorimetry) ont montré que certaines compositions ne présentent pas de pics de cristallisation d’où leur grande stabilité thermique. Il apparaît que la structure de ces verres est plus ouverte d’où les faibles valeurs des propriétés mécaniques. Les verres à base de silice sont opaques aux infrarouges à partir de 2,5 à 3 microns, alors que les verres halogénés et oxyhalogénés sont transparents jusqu'à 7 et 8 microns. Voir les détails
Mots clés : oxyhalogénés, DSC, verre, optique, vitreuses, transparence