Electrotechnique

Nombre total de résultats : 98
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An advanced control approach for current harmonic cancellation using shunt active power filter

N. Hamouda, K. E. Hemsas, H. Benalla, A. Boutaghane  (2015)
Publication

Generally, low harmonic frequencies such as the harmonic of the order 5 and 7 have agreat influence to deteriorate the network current and interim the grid power factor. The objectiveis; to cancel out the selected harmonic order from the network current. The shapes of waves andthe values of the THD of the network current before and after applying the proposed techniqueare introduced. The system is simulated and investigated using MATLAB/Simulink. The resultsprove the effectiveness of the design and control strategy (α-β). This paper deals with design,analysis and simulation of a three phase three wire shunt selective active power filter. Itcompensates the harmonic currents selectively under balanced power network. In order toimprove, the power factor of the supply network, an advanced control approach based on amultivariable filter is adopted. The novelty of the proposed control approach developed in thispaper is to use a multi-variable filter (MVF), which can extract the harmonics content of loadcurrent reference, according to the axis of Concordia. Voir les détails

Mots clés : harmonic, shunt selective active power filter control, power factor, multi-variable filter, MVF, axis of Concordia, THD

Etude Comparative des Techniques de Filtrage Actif Sélectif par le Référentiel Synchrone de Park d-q et l’Approche FMV

Noureddine Hamouda, Kamel Eddine Hemsas, Hocine Benalla  (2014)
Publication

To minimize the total harmonic distortion (THD) and improve the power factor (PF), this paper presents a comparative study between two techniques of shunt power active filter (SPAF) by a selective action of harmonics. These two techniques are based on the SAPF of certain low frequency harmonics (5th and 7th) whose identification of the harmonics of references of the first is made by the axis synchronous d-q of the Park, and the second is done by the approach of self-tuning filter (STF) Thereafter, The active simultaneously filtering of the 5th and 7th harmonics of the current of load catches. The shapes of the signals and the THD values resulting from the results of digital simulations (Matlab-Simulink) elaborate the effectiveness and the best technique of this type of filtering. Voir les détails

Mots clés : PF, THD, Harmonics, SAPF, STF, d-q Park Synchronous Axis

Real Time Implementation of Shunt Active PowerFilter (SAPF)for Harmonic suppression and PowerQuality Improvement

B. Babes, A. Bouafassa, L. Rahmani, N. Hamouda  (2013)
Publication

In this paper, A Shunt Active Power Filter (SAPF) is implemented using a dSPACEDS1104 processor to compensate harmonics and reactive power produced by nonlinearload. The reference source current is computed based on the measurement of harmonicsin the supply voltage and load current. A hysteresis based current controller has beenimplemented in a DSP processor for injecting the compensating current into the powersystem, so that SAPF allows suppression of the harmonics and reactive power componentof load current, resulting in a supply current that is purely sinusoidal. Simulation andexperimental results of the proposed SAPF to meet the IEEE-519 standards are presented. Voir les détails

Mots clés : Harmonics, Power quality, Active power filter, hystérisis comparator, real time control

L’impact d’une Charge Fortement Capacitive Sur la Qualitédu Filtrage d’un FAP Contrôlé Par un Filtre Multi-VariableHautement Sélectif

N. Hamouda, H. Benalla, K. E. Hemsas  (2014)
Publication

This article is devoted to the depollution of the electrical supply networks by shunt active power filter (SAPF). We start by studying a self tuning filter (STF) based on Concordia transformation. This transformation is based on the extraction of the references of harmonic currents in the Concordia axis to compensate network harmonic and by consequence, improve the quality of power system. Next, we present the influence of a strongly capacitive load on the quality of the filtering of a SAPF controlled by a STF approach. This influence is validated by numerical simulations under Matlab-Simulink environment of a system of power PD3 a diode debited in a strongly capacitive load this results prove the major influence of this types of load in filtering quality. Voir les détails

Mots clés : SAPF, harmonic, STF, System of Power PD3, Quality of Energy, Strongly Capacitive Load, Concordia transformation

Modeling, control and fault diagnosis of an isolated wind energy conversion system with a self-excited induction generator subject to electrical faults

Issam Attoui, Amar Omeiri  (2014)
Publication

In this paper, a contribution to modeling and fault diagnosis of rotor and stator faults of a Self-ExcitedInduction Generator (SEIG) in an Isolated Wind Energy Conversion System (IWECS) is proposed. In orderto control the speed of the wind turbine, while basing on the linear model of wind turbine system about aspecified operating point, a new Fractional-Order Controller (FOC) with a simple and practical designmethod is proposed. The FOC ensures the stability of the nonlinear system in both healthy and faulty conditions.Furthermore, in order to detect the stator and rotor faults in the squirrel-cage self-excited inductiongenerator, an on-line fault diagnostic technique based on the spectral analysis of stator currents ofthe squirrel-cage SEIG by a Fast Fourier Transform (FFT) algorithm is used. Additionally, a generalizedmodel of the squirrel-cage SEIG is developed to simulate both the rotor and stator faults taking iron loss,main flux and cross flux saturation into account. The efficiencies of generalized model, control strategyand diagnostic procedure are illustrated with simulation results. Voir les détails

Mots clés : Wind energy conversion systems, fault detection and diagnosis, SEIG, Fractional-Order Controllers

Contribution to the Fault Diagnosis of a Doubly Fed Induction Generator for a Closed-loop Controlled Wind Turbine System Associated with a Two-level Energy Storage System

Issam Attoui, Amar Omeiri  (2014)
Publication

In this article, a contribution to the fault diagnosis of adoubly fed induction generator for a closed-loop controlled wind turbinesystem associated with a two-level energy storage system usingan on-line fault diagnostic technique is proposed. This technique isproposed to detect the rotor fault in the doubly fed induction generatorunder non-stationary conditions based on the spectral analysis of statorcurrents of the doubly fed induction generator by an adaptive fastFourier transform algorithm. Furthermore, to prevent system deterioration,a fractional-order controller with a simple design method isused for the control of the whole wind turbine system. The fractionalordercontroller ensures that the system is stable in both healthy andfaulty conditions. Additionally, to improve the production capacityunder wind speed fluctuations and grid demand changes, a two-levelenergy storage system consisting of a supercapacitor bank and leadacidbatteries is proposed. The obtained simulation results show thatthe objectives of the fault diagnosis procedure and control strategyare reached. Voir les détails

Mots clés : Wind energy conversion systems, adaptive Fast Fourier transform, doubly fed induction generator, fault detection and diagnosis, fractional-order control, two-level energy storage system

CESOP: Computer Aided Ultrasonic Testing with Expertise and Arc Welding Parameters Optimization

F.BETTAYEB, K.Alem, B.MAAMACHE  (1998)
Publication

In metallic constructions, the assemblage techniques are in continual evolution dealing with the technological progress. However one can not insure the quality of an assemblage without proceeding to a quality control. A comparative study on DDT methods, presented during the SMIRT10 in Montrey 1989 has shown that the radiography appears better than the manual ultrasonic testing for the detection of almost welding defects type. Neither it is efficient for the diagnostic, the manual ultrasonic testing gives performances about 50% of detection. On the other hand, the mechanized or automatic ultrasonic testing, insures a probability of detection for plan or volume defects in the order of 80%.On the basis of these estimations, we have judged that it would be judicious to encourage the automatic ultrasonic testing. For this purpose and in the goal to approach the ultrasonic testing method by the radiography on adopting the imagery and the signal processing to the ultrasonic techniques, we present the system, that allows the interpretation automation of the ultrasonic signals identified (1), and simulates the recognition of the defect shape according to the radiography principle (2). Results of this interpretation, provided by << ARCUS >> will be confided to the expert system << SYSO >> (3) for the diagnostic of the defects causes. The exploitation of<< SYSO >> has shown that, a bad determination of welding parameters is the most current defect cause. The << OPTIMA >> system, modeled on the computer methods basis, help to the optimization of the arc welding parameters. These three [3] processes << ARCUS >>, << SYSO>> and << OPTIMA >> cooperate through coupling interfaces to create the: Computer aided Ultrasonic Testing, with Expertise and Arc Welding Parameters Optimization, called << CESOP >>,whose purpose is improving the arc welding quality and increasing as well as the security of the assembled construction. Voir les détails

Mots clés : Welds, During Manufacture

Étude de comportement de la barrière isolante en vue de son optimisation

Samira BENHARAT (En préparation)
Thèse de doctorat

L’augmentation sans cesse de la tension de transport de l’énergie électrique, impose aux concepteurs d’examiner les moyens nécessaires pour réduire les intervalles inter-électrodes. L’insertion d’une barrière isolante entre les électrodes constitue une des solutions. Cette barrière isolante constitue un obstacle à l’évolution directe de la décharge. Son comportement dépend de plusieurs facteurs ; électriques (présence et évolution de la charge d’espace), géométrique (largeur, épaisseur et position de la barrière) et natures de l’environnement et de la barrière. Il est demandé, dans ce travail, d’examiner l’influence de chacun de ces paramètres afin d’établir un critère pouvant permettre d’optimiser la barrière. Voir les détails

Mots clés : calcul de champ électrique, décharges électriques, barrière isolante

Application d’un onduleur multi-niveau a la compensation de la puissance réactive

Khoukha BERAHAL (En préparation)
Thèse de doctorat

L’industrie de l’énergie électrique et de plus en plus confrontée à des problèmes liés à de nouvelles contraintes qui touchent différents aspects de la production, du transport et de la distribution de l’énergie.Les éléments FACTS (Flexible Alternative current Transmission Systems) apportent des solutions nouvelles pour faire faces à ces contraintes.Les convertisseurs à niveaux multiples sont une nouvelle génération de convertisseurs qui prend sa place dans le domaine de la haute tension. Les facteurs hauts qui les caractérisent sont surtout une meilleure tenue en tension et les forme d’ondes en comparaison avec les structures traditionnelles englobent. C’est dans le but d’exploiter les avantages des convertisseurs multi-niveaux pour la compensation de la puissance réactive dans les réseaux électriques que ce travail de recherche s’insert. Voir les détails

Mots clés : puissance réactive, FACTS, STATCOM, Onduleur de tension

Identification et commande par la théorie des intervalles

Halim MERABTI (En préparation)
Thèse de doctorat

Dans cette thèse, nous avons abordé plusieurs objectifs dans le domaine de la commande prédictive : • Le développement d’un algorithme de commande prédictive robuste basé sur la théorie des systèmes dont les incertitudes sur les paramètres sont décrites par des intervalles flous. Cet algorithme est utilisé pour la commande des systèmes non linéaires. • L’utilisation de metaheuristiques pour la solution du problème d’optimisation de la commande prédictive ; plusieurs metaheuristiques ont été utilises et comparés • L’optimisation multi objectifs dans le cadre de la commande prédictive. En effet, dans un grand nombre de problèmes du monde réel, il s'agit d'optimiser simultanément plusieurs objectifs d'un même problème souvent conflictuels et leur résolution dans un temps raisonnable devient nécessaire. Dans ce travail, nous nous sommes intéressés à l'optimisation multi objectifs par l'algorithme PSO : Particle swarm optimisation. Voir les détails

Mots clés : commande prédictive, algorithme PSO