Liste des documents

Nombre total de résultats : 1844
Pertinence Titre A-Z Plus récents Plus anciens
10 25 50
Année de publication
et

Real Time Implementation of Grid Connected Wind Energy Systems: Predictive Current Controller

N. Hamouda, B. Babes, S. Kahla, Y. Soufi  (2019)
Article de conférence

This work, suggests a new control strategy usingFinite-Control-Set Model-Predictive-Control (FCS-MPC) for thecontrol of a wind turbine system (WTS) based on PermanentMagnet Synchronous Generator (PMSG). The consideredcontroller is separated on two parts: FCS-MPC-based on thecurrent control loop for the single switch mode rectifier tooptimally release the maximum wind power, and FCS-MPCbased on the voltage control loop for the voltage source inverterto enhance the THD of grid currents. A wind energy systemprototyping platform was developed and accomplished in thelaboratory, and the experimental results are provided to verifythe performances of the considered FCS-MPC strategies. Voir les détails

Mots clés : Finite-Control-Set Model-Predictive-Control (FCSMPC), Permanent Magnet Synchronous Generator (PMSG), Wind Turbine System (WTS), Maximum Power Point Tracking (MPPT), Grid Connected, Experimental Results

A DC/DC Buck Converter Voltage Regulation UsingAn Adaptive Fuzzy Fast Terminal Synergetic Control

Noureddine Hamouda, Badreddine BABES, Mohamed MEZAACHE  (2019)
Article de conférence

In this paper, an adaptive fuzzy fast terminalsynergetic voltage regulation for DC/DC buck converter isdesigned based on recently developed synergetic theory and aterminal attractor method. The advantages of presentedsynergetic control include the characteristics of finite timeconvergence, insensitive to parameters variation and chatteringfree phenomena. Rendering the design more robust, fuzzy logicsystems are used to approximate the unknown parameters in theproposed controller without calling upon usual modellinearization and simplifications. Taking the DC/DC buckconverter in continuous conduction mode as an example, thealgorithm of proposed synergetic control is analyzed in detail. Allthe simulation results demonstrate the effectiveness and the highdynamic capability of the proposed AF-FTSC control techniqueover the FTSC strategy Voir les détails

Mots clés : synergetic control, fuzzy logic system, terminal technique, finite time convergence, DC/DC buck converter

Elaboration et caractérisation de couches minces d'oxyde dezinc dopées aux métaux pour des applicationsphotovoltaïques et en détection de gaz.

BOUGHELOUT Abderrahmane (2019)
Thèse de doctorat

Le travail présenté dans cette thèse porte sur l’élaboration et l’étude de films d’oxydes  métalliques d’oxyde de zinc (ZnO) non dopé et dopé à l’aluminium (AZO) et d’oxyde de cuivre  (Cu2O) dont les propriétés sont modulées par la variation de la pression partielle d’oxygène (PO2) dans l’intervalle [0,05 - 1,30 mbar] tout en maintenant la pression d'argon fixée à 0,05 mbar, en vue de leur application dans différents domaines. Les dépôts ont été réalisés en utilisant la technique de pulvérisation DC et le dépôt laser pulsé (Pulsed Laser Deposition) (PLD). Les différentes propriétés des échantillons ont été étudiées à travers des analyses de diffraction de rayons X (XRD), de spectroscopie Raman, de transmissions optiques (UV – vis), de microscopie électronique à balayage (MEB) et de mesures électriques d’effet Hall et de caractéristiques courant-tension (I-V) dans le cas des hétérojonctions. Tous les résultats révèlent l’influence particulière des différents intervalles de valeur de la pression d’oxygène, sur les films déposés de ZnO et de Cu2O. Un traitement thermique par un laser infrarouge de différentes énergies, effectué sur les couches de Cu2O a affecté considérablement leurs différentes propriétés. Des hétérojonctions Cu2O/AZO et Cu2O/ZnO/AZO ont été déposées sur des substrats de verre par dépôt de laser pulsé. Elles ont aussi été caractérisées par microscopie à force atomique (AFM) et par microscopie électronique à balayage (MEB). On montre que l’insertion d’une couche de ZnO entre Cu2O et Le film AZO dans l’hétérojonction augmente la taille moyenne des grains et améliore la rugosité de la surface supérieure de l’hétérojonction (surface de la couche AZO). Les mesures de courant-tension (I-V) révèlent que les hétérojonctions réalisées, présentent des comportements remarquables de diodes. La présence du film mince intermédiaire de ZnO réduit de manière significative les courants parasites et de fuite à travers la barrière, améliore la qualité de l’hétérostructure, modifie la bande d’énergie entre les couches AZO et Cu2O en la rendant moins abrupte (plus lisse) et contribue à diminuer la possibilité de la recombinaison des porteurs de charge à l'interface, augmentant ainsi leur durée de vie. L’activité photocatalytique des films ZnO et Cu2O a été étudiée au moyen d’essais sur la photodégradation de la rhodamine B (RhB) et du méthyl-orange (MO) sous irradiation directe de rayons solaires. Une étude comparative a été menée entre le ZnO et le Cu2O pour la décoloration de la Rhodamine B et du Methyl-orange sous la lumière solaire. Les résultats ont montré que les films de ZnO présentent une activité photocatalytique plus grande avec la rhodamine B que le méthyle orange, qui présente plutôt une photodégradation plus importante avec les films de catalyseur de Cu2O. Après exposition des films à la lumière solaire pendant 6 h, un taux d'élimination de 81,69% a été obtenu pour le méthylorange sur des films de Cu2O, tandis que pour la rhodamine B, le meilleur taux d'élimination (60,85%) a été obtenu avec le ZnO.La pression partielle d’oxygène, le traitement thermique au cours des dépôts sont des paramètres clé affectant les propriétés des films d’oxydes métalliques déposés, leur conférant une application appropriée. Voir les détails

Mots clés : oxydes transparentes conducteurs, pulvérisation cathodique, caractérisation électrique, dopage des semiconducteurs, caractérisation optique, caractérisation structurale.

Study and development of a new process for the treatment and purification of industrial effluents contaminated by metals by electrodeposition

Souad brick chaouche, Ahmed HADDAD, AICHA BENSMAILI  (2019)
Article de conférence

Currently, Electrochemical methods find wide application in the treatment of industrial effluents to reduce their organic matter content, in inorganic sulfur compounds and nitrogen, or in harmful metals for the environment. Electrochemistry is not only applied to wastewater, but also on contaminated soils, incineration residues or sewage sludge wastewater from the metallurgical industry. Electrochemistry has proved its effectiveness, which allowed him to integrate the environmental industry. Environmental electrochemical technologies allow to control pollution, to recycle materials, to carry out the rehabilitation of sites, monitoring (monitors and sensors for gases and liquids), the efficient conversion of energy, the prevention of corrosion, removal of contaminants and disinfection of water. Electrochemical processes can therefore be efficient and economical when properly designed, and they integrate harmoniously with the environmental industry. These processes require compact installations and can thus integrate into existing industrial waste treatment chains. The present work aims so the elaboration of an electrochemical process of treatment and purification of industrial effluents contaminate with metals. Indeed, the use of this technique can allow both the elimination of these metals by electroplating on a cathode, a recovery of metals, a saving of precipitation reagents and a reduction in the amount of sludge to be removed, as well as surface treatments where the applications concern gold recovery, silver, copper, cadmium, nickel, zinc, iron and lead ... etc. The metal that can be recovered in the form of valorizable cathodes, which allows the depollution of the environment. This work requires in-depth studies of design considerations and the development of an electrolytic cell. Voir les détails

Mots clés : electrochemical, environment, pollution

PredictiveControl of a Grid Connected PVSystemsIncorporating Active Power FilterFunctionalities

N. Hamouda, B. Babes, S. Kahla, Y. Soufi, J. PETZOLDT, T. Ellinger  (2019)
Article de conférence

This paper presents a multifunction operation of adouble stage grid connected photovoltaic system, with insertionthe active power filter (APF) functionalities. This system is usedto compensate the reactive power, suppression harmonicscurrents supply the nonlinear loads and inject the active powerinto grid. Our work is focused on the grid side, a perturbationand observation control is used to reach the maximum powerpoint tracking (MPPT) regardless of solar radiation. On the gridside, a modified instantaneous active and reactive poweralgorithm (P-Q) based on a multi-variable filter (MVF) is usedin order to identify the harmonics currents reference underdistorted source voltage condition, also a modified predictivecurrent control (PCC) algorithm is used to control the sourcevoltage inverter in order to ensure compensate reactive powerand harmonic currents, feed the non linear load and inject thesurplus generated power into the grid. In Matlab/Simulinksoftware, the proposed control scheme is investigated under loadchange and radiation change conditions. Simulation resultsshows that the proposed PCC of the APF guarantees a flexiblesettlement of real power amounts exchanges with the grid with ahigh power factor operation. Furthermore, the grid currentrecovers its sinusoidal waveform with a total harmonic distortion(THD) meet to IEEE-519 standard Voir les détails

Mots clés : Photovoltaic system (PV), activ power filter (APF), Predictive current control (PCC), active and reactive power theory (P-Q), multivariable filter (MVF), total harmonic distortion (THD)

Conception of a friction stir welding tool

M. AISSANI, S. Gachi, D.H. BASSIR, F. Boubenider, Y. Benkedda  (2008)
Article de conférence

Friction stir welding is a new process that allows a solid-state joining technology of metallic components. Applications and development within this approach has incr eased during the last decade. In this process, the geometry of friction tool plays a fundamental role to obtain suitable microstructures in the weld and the heat affected zones, thus it will be then possible to improve the strength and fatigue resistance of the joint. Among the articles related to the friction process, only few have treated the manufacturing process of the tool. In this work, we will focus on this last point. To increase the welding quality and the process reliability, the design of the tool includes a shaft-spring-based system aimed at avoiding premature damage, furthermore to allow the measure of applied friction pressure. Our improved friction tool has then been tested for applied this welding technique on Al-2024 and Al-7075 aluminium alloys sheets. The weld quality has been evaluated by means of a microstructure analysis and micro-hardness measurements. The ability to increase the welding speed, the changes of the crystalline plans orientation in the mixed part of thermo-mechanically affected zone and grains sizes observed in micrographics underline the effect of the pin geometry and its displacement. The micro-hardness curve shows good mechanical properties. Finally, the obtained results show a su ccessful welding with accep table quality and open new interesting perspectives. Voir les détails

Mots clés : Aluminium, conception, Friction Stir Welding, tool, Micro-hardness

Microstructural Study of Thin Films CuFe Obtained by ThermalEvaporation of Nanostructured Milled Powde

H. Mechri, A. Haddad, M. Zergoug, M. Azzaz  (2017)
Publication

Commercial copper and iron powders were used as starting materials. These powderswere mechanically alloyed to obtain Cu(100-x) Fex supersaturated mixture. The milling duration waschosen in such a way as to obtain a nanostructured mixture and to form a supersaturated solidsolution of CuFe; the powder mixture was used to deposit CuFe on a glass substrate.The elaboration of our films has been carried out using thermal evaporation process (physical vapordeposition) under 1 × 10-6 mbar vacuum from an electrically heated tungsten boat, using thesupersaturated solid solution Cu(100-x) Fex powder obtained by mechanical alloying. The filmsdeposition has been done on glass substrates. In this study, we present the composition effect on thestructural and magnetic proprieties of Cu(100-x) Fex powder and thin films. The chemicalcomposition, structural and magnetic proprieties of milled powders and thin films were examinedby SEM, TEM, XRD, XRF and VSM. Voir les détails

Mots clés : thin film, CuFe Solid Solution, microstructure, DRX, MET, VSM

Caractérisation morphologique et mécanique deu polyéthylène semi cristallin extrudé

LAABED Abdellatif (2012)
Mémoire de magister

La tuyauterie en polyéthylène a haute densité (PEHD) sont utilisés pour la conduite d'eau potable marqué par un trait bleu, et la conduite du gaz naturel de ville marqué par un trait jaune. Le but de cette étude et de caractérisé ces matériaux morphologiquement et surtout mécaniquement, due a un taux de crisallinté remarquable, qui sera quantifié par plusieurs méthodes de caractérisations. cette cristallinité est causé par son historique de fabrication qui est l'extrusion.  Voir les détails

Mots clés : Polymere, PEHD, extrusion, Cristallinité, DSC

CFD method for analysis of the effect of drill pipe orbital motion speed and eccentricity on the velocity profiles and pressure drop of drilling fluid in laminar regime

Hicham Ferroudji, Ahmed Hadjadj, Titus Ntow Ofei, Mohammad Aziz Rahman, Ibrahim Hassan, Ahmed HADDAD  (2019)
Publication

Due to the axial and lateral loads applied to the drill pipe during the drilling process, this last may loseits stability and begins to make complicated motions like the orbital one. In the present paper, thisorbital motion of the drill pipe is modelled using CFD method to investigate its effect on the axial andtangential velocity profiles in the wide and narrow regions of the eccentric annulus (E=0.2, E=0.4,E=0.6 and E=0.8), as well as, effect of the orbital motion speed on pressure drop gradient of drillingfluid is studied. Our results show that increment of the orbital motion speed from 100 to 400 rpmcauses an increase of 913% of the maximum axial velocity, however, this increment is estimated atabout 100% in the case where the drill pipe makes pure rotation for the eccentric annulus (E=0.8),Moreover, orbital motion of the inner pipe prevents the secondary flow to appear in the wide region ofeccentric annulus. For all eccentricities, the tangential velocity of the orbital motion case in the narrowregion for 400 rpm speed is 120% higher than pure rotation one Voir les détails

Mots clés : Orbital motion, eccentricity, velocity profiles, pressure drop, drilling fluid, laminar flow

Numerical study of parameters affecting pressure drop of power-law fluid in horizontal annulus for laminar and turbulent flow

Hicham Ferroudji, Ahmed Hadjadj, Ahmed HADDAD, Titus Ntow Ofei  (2019)
Publication

Efficient hydraulics program of oil and gas wells has a crucial role for the optimization of drilling process. In the presentpaper, a numerical study of power-law fluid flow through concentric (E = 0.0) and eccentric annulus (E = 0.3, E = 0.6 andE = 0.9) was performed for both laminar and turbulent flow regimes utilizing a finite volume method. The effects of innerpipe rotation, flow behavior index and diameter ratio on the pressure drop were studied; furthermore, the appearance anddevelopment of secondary flow as well as its impact on the pressure drop gradient were evaluated. Results indicated thatthe increment of the inner pipe rotation from 0 to 400 rpm is found to decrease pressure drop gradient for laminar flow inconcentric annulus while a negligible effect is observed for turbulent flow. The beginning of secondary flow formation in thewide region part of the eccentric annulus (E = 0.6) induces an increase of 9% and a slight increase in pressure drop gradientfor laminar and turbulent flow, respectively. On the other hand, the variation of the flow behavior index and diameter ratiofrom low to high values caused a dramatic increase in the pressure drop. Streamlines in the annulus showed that the secondary flow is mainly induced by eccentricity of the inner pipe where both high values of diameter ratio and low values of flowbehavior index tend to prevent the secondary flow to appear. Voir les détails

Mots clés : Computational fluid dynamics (CFD) · Power-law fluid · Pressure drop · Secondary flow