Génie électrique

Nombre total de résultats : 75
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Effect of Zinc/Cadmium Proportion in the Properties of CdS LayersDeposited by Chemical Bath Depostion Method

R. Zellagui1, 2, H. Dehdouh2, F. boufelgha2, A. Boughelout2, T. Sahraoui1, D. Chaumont3, M. Adnane1 (2018)
Article de conférence

Cadmium poisoning and the cost of panel recovery which is very expensive and difficult in the buffer layersof CdS in solar cell, for these two drawbacks, we do a search on the effect of proportion of zinc/cadmium inthe properties layers of CdS. For this, our studies study the properties of CdxZn1-xS layers deposited bychemical bath (CBD). CdZnS thin films were synthesized by chemical bath deposition (CBD) with differentdeposition protocols to optimize deposition parameters such as temperature, deposition time, ionconcentrations and pH. The surface morphology, structural, optical and chemical properties of the CdZnS thinfilms were studied by SEM, XRD, Raman and UV-visible spectrophotometer. The transmittance is 80% inthe visible region 300 nm - 800 nm; the crystalline structure is hexagonal for x ≥ 0.5 and cubic for x≤0.5, thegrain size is between 85.7 and 100 nm. It is observe that the transmittance and the shape change with theconcentration of zinc in the solution; this result favours the application of these films in solar cells application.Voir les détails

Mots clés : CdZnS, chemical bath, SEM, Raman, solar cells, thin films.

Les techniques de reconnaissance de Formes Application : à la reconnaissance de l’écriture Arabe

Rachid Zaghdoudi (2018)
Thèse de doctorat

Le domaine de la reconnaissance de l’écriture arabe manuscrite a reçu un intérêt de recherche intensif aux cours des deux dernières décennies et se concrétise aujourd’hui par un grand nombre d’applications opérationnelles. Malgré ces avancées, le problème reste ouvert à la recherche et à l’expérimentation à cause des caractéristiques morphologiques complexes du manuscrit arabe qui sont à l’origine de la défaillance des traitements. Les travaux de recherches présentés dans cette thèse s’inscrivent dans ce cadre et constituent une contribution au domaine de la reconnaissance de l’écriture arabe manuscrite. Dans un premier temps, nous proposons une approche globale basée sur une combinaison parallèle de classifieurs pour la reconnaissance hors ligne de mots arabe manuscrits. Le système développé s’articule autour de quatre modules distincts : prétraitement, extraction de primitives, classification basée sur deux types de classifieurs : SVM et k plus proches voisins flou et un module de combinaison. Des expériences ont été effectuées sur des images de la base de référence INF/ENIT ont montré l’efficacité du système proposé.En second temps, nous présentons un nouvel algorithme de segmentation en caractères des mots arabes manuscrits. Cet algorithme est fruit d’une coopération entre un ensemble de règles morphologiques spécifiques à l’écriture arabe (AMS) et un classifieur SVM mono classe, dont la tache principale consiste à accepter ou rejeter les points de segmentation primaires générées par le module AMS. Il a montré de bons résultats de segmentation sur des mots extraits de la base de données de référence IFN/ENIT. Voir les détails

Mots clés : reconnaissance de l’écriture arabe manuscrite ; combinaison de classifieurs ; séparateurs à vaste marge ; k plus proches voisins flou ; la transformée en cosinus discrète, histogrammes des gradients orientés ; segmentation.

Contribution to Reconfigured Multi-Level Inverter FedDouble Stator Induction Machine DTC-SVM Control

O. F. Benaouda, A. Bendiabdellah, B. Cherif (2016)
Article de journal

The Dual Stator Induction Machine (DSIM) meets well with the need for high power applications. In the recent years, it has been increasingly used for variable speed drives. However, its control strategy is still a subject of research due to its complex structure, though it offers more reliable application in use due to the presence of double stators. The fault detection and localization in an inverter are profitable for better diagnosis and the inverter reconfiguration is the most required process to ensure acceptable service continuity. This paper tackles, on the one hand, a control strategy based on the Direct Torque Control combined with the Space Vector PWM of a DSIM (DTC-SVM-DSIM) and on the other hand, a three-level inverter fault detection and localization, reconfiguration of the inverter when operating under open-circuit IGBT switch faults. Several results are presented to illustrate the enhancement of torque and flux quality owed to the proposed control strategy and also to show the improvement of the open-circuit fault detection and localization method for better diagnosis as well as the inverter reconfiguration impact on the drive system service continuity.Voir les détails

Mots clés : DSIM, Multi-level Inverter, NPC, DTC, SVM, Reconfiguration

Bearing Fault Diagnosis Using De-noising Techniques Based on EMD Combined with Coefficients Correlation

Omar Fethi BENAOUDA, Rabah ABDELKADER, Abdelhafid KADDOUR, Ziane DEROUICHE (2018)
Article de conférence

The vibration signals of a rolling bearing contain important information which can be used in early defect detection and diagnosis. This signal is usually noisy and the information about the fault can be lost. In this paper, a new denoising method based on Empirical Mode Decomposition Iterative Interval Thresholding and estimation of the correlation coefficient (EMD-corIIT) is presented. The results are compared with others proposed methods. The application of this technique to the experimental results shows that this method can extract effectively the fault features of rolling bearing compared with the others cited methods.Voir les détails

Mots clés : Denoising EMD, thresholding, vibration signal, Bearing Fault, Correlation Coefficients

Desired Closed-Loop Based Self-Tuning Fractional PID Controller for Wind Turbine Speed Control

N. Fergani, A. Charef, I. Attoui (2015)
Article de conférence

Lately, fractional PID controller has gained more interests because it involves two more tuning parameters, the fractional order integration and the fractional order differentiation, in their structure. This type of controller has been introduced in the control system theory in a continuous effort to enhance the system control quality performances. In this paper a self-tuning fractional PID controller for wind turbine speed control is proposed. The fractional PID controller’s five parameters are self-tuned as the system dynamics or operating points change using formulas based on adesired closed loop response. A simulation study of the wind turbine speed control has been done to demonstrate and validate the performance and effectiveness of the proposed control scheme.Voir les détails

Mots clés : Fractional PID controller, self-tuning, wind turbine speed control

Analysis and evaluation of the impact of climatic conditions on thephotovoltaic modules performance in the desert environment

A Bouraiou, M. Hamouda, A. Chaker, M. Mostefaoui, S. Lachtar, M. Sadok, N. BOUTASSETA, M. Othmani, I. Attoui (2015)
Article de journal

The main objective of this study is to investigate the impact of climatic conditions on the performance ofphotovoltaic modules installed in the desert region in south of Algeria. Firstly, the performance ofISOFOTON 100 module under daily weather conditions is evaluated. Next, the effects of partial shadingand accumulation of sand dust for a period of two months on power loss and the current–voltagecharacteristics of photovoltaic modules are examined. Finally, the visual inspection of the degradationof the UDTS 50 modules such as discoloration of encapsulant and delamination show the influence ofhigh temperature and the other climatic factors in the Saharan environment after a long time exposureof more than 10 years observed in the field at the Unit of Research in Renewable energy URERMS Adrar.The performance degradation is also assessed using (I–V and P–V) curves normalized at STC conditioncompared with the nominal STC data given by the manufacturer. The experimental results show thatthe performance parameters such as maximum output current (Imax), maximum output voltage (Vmax),maximum power output (Pmax), open-circuit voltage (Voc), short-circuit current (Isc) and fill factor (FF)of UDTS 50 modules are degraded after these years of exposition.Voir les détails

Mots clés : Photovoltaic module, Performance evaluation, degradation, Desert environment

AN INTELLIGENT ONLINE SCHEME BASED K-NEAREST NEIGHBOR CLASSIFIER FOR GEAR SYSTEM FAULT DIAGNOSIS AND CLASSIFICATION

I. Attoui, B. Oudjani, M.S. BOUAKAZ, K. CHETTAH, W. RICHI (2018)
Article de conférence

Gear system faults in all sorts of rotating machines can result in partial or total breakdown,destruction and even catastrophes. By implementation of an adequate fault detection system, thereliability, productivity, safety and availability of the gearboxes that are used to transfer rotating powersource to other devices, provide speed, and torque conversions can be improved. In this paper, aspecific interest is carried to correctly identify type, location, and class of different defects that canappear in the gear and bearing in a gear system with various combinations under different speeds andloads. The solution is based on a three-step algorithm. The first step, based on the Wavelet PacketTransform WPT and FFT algorithms, is used to extract the features of the different sub-bandsfrequencies in the vibration signal from a gear system. Then, in the second step, a dimensionalityreduction based Linear Sequence Discriminant Analysis LSDA algorithm is conducted to reducecomputational overhead for diagnosis and to improve classification performance. Finally, the reducedfeatures were used as the input to a k-nearest neighbor classifier to evaluate the system diagnosisperformance. Based PHM Data Challenge, the experimental results obtained from real gear systemvibration signals for eight different health gearbox conditions demonstrated that the proposed methodis effective in both feature extraction, feature reduction, and also fault classification.Voir les détails

Mots clés : Data Analysis, Gear System, Fault Diagnosis, classification, Linear Sequence Discriminant Analysis.

Electromagnetic Interference Caused by High Voltage Power Lines on Buried Oil Pipelines

M.Ouadah, M.Zergoug, A.Younes (2012)
Article de conférence

The electromagnetic interference caused by power transmission lines to oil and gas buried pipelines is under investigation for many years. Especially during fault conditions, large currents and voltages are induced on the pipelines that may pose danger to working personnel or may accelerate the corrosion of the pipeline’s metal. In this research, the induced voltage in the oil buried pipelines due to the magnetic fields produced by nearby 400kV transmission lines have been computed. This effect results in a corrosion process which we have proposed some solutions.Voir les détails

Mots clés : C Interference, Induced Voltages, Electric Power Transmission Lines, pipeline, corrosion, cathodic protection.

Analysis of the Electromagnetic Interferences betweenOverhead Power Lines and Buried Pipelines

M'hamed OUADAH, Mourad ZERGOUG (2014)
Article de journal

The Analysis of electromagnetic interference between high voltage overhead power transmission lines and nearby gas/oil pipeline has been a topic of growing interest for many years. When pipelines are located in shared row with power lines, the pipeline can incur high induced voltages and currents due the AC interference. The induced voltage on pipeline can be dangerous for operator to touch the pipeline as well as pipe corrosion can result from AC discharge. This research evaluates and analyzes the electromagnetic interference effects on oil and gas buried pipelines created by the nearby high voltage transmission lines. The aim is to evaluate the AC corrosion likelihoods of pipelines and suggest proper mitigation solutions.Voir les détails

Mots clés : AC interference, Induced Voltages, Electric Power Transmission Lines, pipeline, AC Corrosion, Corrosion protection.

FAULT DIAGNOSIS OF ROTATING MACHINERY BASED ON VIBRATION SIGNAL ANALYSIS

I. Attoui, B. Oudjani, W. RICHI, K. CHETTAH, N. Fergani, N. BOUTASSETA (2017)
Article de conférence

In modern diagnostic approaches, the most important step consists in generating the features related to the faults evolution that is able to identify the relationships between the measured signal and the condition of the monitored system. This paper investigates an on-line algorithm that can make a robust fault diagnosis about the failure of rolling-element bearing and unbalance fault in rotating machinery. For this reason, based only on the measured vibration signals for different conditions, this paper propose many feature parameters that can be significantly reduced using a wrapper method to improve the effectiveness of the diagnostic approach. In order to demonstrate the effectiveness of the proposed diagnosis method for rotating machines fault diagnosis, different testing data for different fault conditions under different speeds are used. The experimental results demonstrate that a high accuracy has been achieved for unbalance faults and rolling-element bearing faults diagnosis.Voir les détails

Mots clés : Fault Diagnosis, Vibration analysis, Bearings Fault, unbalance Fault