Nombre total de résultats : 98
Pertinence Titre A-Z Plus récents Plus anciens
10 25 50
Année de publication

Répartition de champ électrique dans un système pointe-plan avec barrière isolante

BENHARAT Samira, Slimane Bouazabia  (2015)
Article de conférence

The objective of our work is the study by numerical simulation of the distribution of the electric field according to geometric measurements of the insulating barrier and its position in the inter-electrodes gap Voir les détails

Mots clés : Electrical discharge, insulating barrier, finite element, electrical field

Fault tolerant control of energy processes

boutasseta nadir (2019)
Thèse de doctorat

This work deals with the control of energy systems subject to faults. The objective is toaccommodate faults by the design of a control law that takes into account the existence ofinternal faults and dysfunctions caused by external environment.Energy systems are characterized by the dependence of their performance on energyefficiency, the total efficiency is the result of the operation of elementary energy processesto verify the final objective which is the production of energy in its final form. Thesupervision of these processes and tolerance to faults allow the improvement of individualperformances and the achievement of global efficiency at a lower cost.In this context, renewable energy conversion processes are characterized by the aspect oftheir dependence on climatic conditions and direct exposure to outdoor environment,resulting in the occurrence of different types of faults and dysfunctions. Solar photovoltaicrenewable energy generation systems are considered in this work as they dominaterenewable electricity capacity expansion. The study of the effect of various abnormalevents and degraded operating modes of solar photovoltaic systems is performed and afault-tolerant control law is proposed to enhance the efficiency of these energy processes.A reconfiguration of controller is designed to switch between an improved current-basedparticle swarm optimization technique and the incremental conductance algorithm.Practical implementation of the proposed approach shows excellent performance in realoperating conditions when compared to traditional maximum power point algorithms. Voir les détails

Mots clés : fault-tolerant control, energy systems, renewable energy, Solar energy, Photovoltaic, Maximum Power Point Tracking, Particle Swarm Optimization

Modélisation électromagnétique d’un système de contrôle non destructif par courant de Foucault

Oualid SEMAOUN, Kahina MERMOURI  (2014)
Mémoire de Master

Nous avons étudié dans ce mémoire un modèle électromagnétique du contrôle non destructif par courant de Foucault d’un système sonde-pièce d’une géométrie 2D axisymétrique. Notre recherche bibliographique étendue, nous a permis de consulter assez de modèles physiques récents, ainsi que les méthodes numériques exploitées dans la résolution de la formulation magnétodynamique en régime fréquentiel. Pour notre cas, on a opté pour l’application champ magnétique du module AC/DC de COMSOL à la base des éléments finis, à fin de calculer le potentiel vecteur magnétique azimutal représentant une variable principale pour la détermination de toutes les autres grandeurs électromagnétiques et électriques du système. Partant d’une source d’excitation sinusoïdale du capteur placé à proximité d’une pièce à matériau conducteur, on est arrivé au calcul de la variation d’impédance aux bornes du capteur. Cette grandeur électrique, résultante de la topologie de perturbation des lignes de courant de Foucault, nous informe sur l’existence des défauts à la surface de la pièce. Expérimentalement, nous avons pratiqué un balayage de la sonde sur une pièce à deux défauts distants et de profondeur différente, l’impédance mesurée est plus grande lorsque le défaut est plus profond. Ces résultats ont été comparés avec ceux obtenus numériquement, et l’erreur relative a été de l’ordre 3%. Voir les détails

Mots clés : contrôle non destructif, Courant de Foucault, Électromagnétisme, méthode des éléments finis, Impédance d’un capteur, Défauts.


DRICI Djalel, Merabet hichem, Aouabdi Salim, Boudiaf Adel  (2018)

The fault of broken rotor bars in a three phase induction motor is diagnosed by using the wavelet Packet analysis. In this paper Daubechies wavelet is selected as the wavelet base and the wavelet coefficient is obtained from the wavelet transform of current signal of the faulty induction motor. Tghe energy of wavelet components appear to be useful for detecting different electrical faults. In this paper we will study the problem of broken rotor bars Voir les détails

Mots clés : Wavelet Packet, Analysis, diagnosis fault, induction motor, broken bar

Sensor Monitoring of the Concentrations of Different Gases Present in Synthesis of Ammonia Based On Multi-Scale Entropy and Multivariate Statistics

Aouabdi Salim, Taibi Mahmoud  (2015)

This paper presents powerful techniques for the development of a new monitoring method based on multi-scale entropy (MSE) in order to characterize the behaviour of the concentrations of different gases present in the synthesis of Ammonia and soft-sensor based on Principal Component Analysis (PCA). Voir les détails

Mots clés : Ammonia synthesis, Concentrations of different gases, Soft sensor, Multi-scale entropy, multivariate statistics.

Evaluating the Flicker caused byElectric Arc Furnacethrough the Multi-scale Entropy MSE Algorithm SampEn

Aouabdi Salim, BENDJAMA Hocine  (2018)
Article de conférence

This paper presents a new method to evaluate the Arc voltage quality in electric arc furnace (EAF). It has been shown that is possible to allow the representation of nonlinear dynamics and coupling effects between different waves for irregularity of electrical signals issued by electrical components though multi-scale entropy algorithm SampEn. This work shows the behavior of the feature extraction with SampEn when it’s used to evaluate the signals that deviate the arc voltage in (EAF). Flicker effect with voltage imbalances are analyzed by means of the SampEn concept. Voir les détails

Mots clés : Entropy, Arc voltage signals quality, Flicker effect, voltage imbalance

Improving the Power Quality of the Arc WeldingSupply using an Active Power Filter

N. Hamouda, B. Babes, A. Boutaghane, S. Kahla, R. AMRAOUI, M. Mezaach  (2018)
Article de conférence

This paper presents a new circuit topology suitablefor arc welding inverter applications, this topology is based onshunt active power filter (APF), in order to improve the powerquality and reduced the total harmonic distortion (THD) byconsequently improve the power factor (PF), a modified activeand reactive power method (p-q),which is combined with aself-tuning filter, is used to identify the harmonics currentsreferences of the load current, Also a PI controller has beenused to maintain the level of DC-link voltage at a constantvalue and improves its dynamic response; the voltage sourceinverter of APF is controlled by hysteresis current controller.The Major favorable features of this topology like fastresponse to load and source voltage conditions will result inbetter welding performance. The performance of the entiresystem is evaluated on the basis of THD of the source current,input power factor, dynamic response, voltage regulation androbustness to prove its effectiveness in terms of excellent powerquality. Voir les détails

Mots clés : arc welding, Active power filter (APF), power factor (PF), total harmonic distortion (THD), modified active and reactive method (p-q)

Analysis and Simulation in Electrical Networks Using SSSC Device for Damping Power Oscillations

M. MEZAACHE, S. BENHARAT, A. Boutaghane, S. CHAOUCH, B. Babes, R. AMRAOUI, O. BENAOUDA, N. Hamouda  (2018)
Article de conférence

A large power system has many interconnections and bulk power transmissions over long distance. As a result, there low frequency inter-zone oscillations which make the system vulnerable to cascade failures. Many different methods have been proposed to alleviate the oscillations in the power system. For many years, Power System Stabilizer (PSS) has been one of the devices traditionally used to dampen oscillations. It is reported that during some operating conditions, PSS may not effectively attenuate oscillations; for this reason, other effective alternatives are required in addition to PSSs. On the other hand, the advent of FACTS has led to a new and more versatile approach to controlling the power system in a desired way. These devices based on very advanced power electronics components (GTO, IGBT,…). FACTS devices according to their network connection are distinguished countervailing series, shunt and hybrid such as: SSSC, ASVC and IPFC, respectively. One of the best-innovated Flexible AC Transmission System devices is the Static Synchronous Series Compensator. The purpose of this paper is to study the control functions provided by the SSSC in controlling the power flow of the load capacity of power lines. Voir les détails


Fault-tolerant power extraction strategy for photovoltaic energy systems


Photovoltaic (PV) arrays are subject to various types of environmental disturbances and component-related faults that affect their normal operation and result in a considerable energy loss. The nonlinear current-voltage (I-V) characteristic curve of the PV array prevents the detection and isolation of the faults and also makes the tracking of the maximum power operating point (MPP) more difficult. Fault detection and identification (FDI) techniques have been proposed to detect the presence of faults and isolate them. Many maximum power point tracking (MPPT) methods have been proposed to find the best operating point in the presence of disturbed environmental conditions. However, existing FDI methods do not consider the tracking of the MPP in faulted operating conditions, and available MPP tracking methods do not consider the occurrence of faults in the PV system. The objective of this study is to propose a fault-tolerant control (FTC) strategy to detect the presence of abnormal operating conditions and reconfigure the MPPT procedure to search for the new suboptimal operating point. The FDI method is based on monitoring the PV panel generated power for the presence of abrupt changes; the MPPT reconfiguration is based on a combination between Incremental Conductance (IncCond) Algorithm and an Improved Current-based Particle Swarm Optimization (ICPSO) tracking technique. Simulation and experimental results show an excellent performance of the proposed FTC method in the presence of various types of faults. Voir les détails

Mots clés : Fault-tolerant control (FTC), Particle swarm optimisation (PSO), Photovoltaic (PV) arrays, Line-Ground fault, Line-line fault, Partial shading, Maximum Power Point Tracking (MPPT)

A Fuzzy Logic Based Approach for the monitoringof Open Switch Fault in a SVM Voltage SourceInverter fed Induction Motor Drive

Hichem MERABET, Tahar Bahi, Khouloud BEDOUD, Djalel DRICI  (2018)

The reliability of power electronics system such as three phase inverter is important in many industrial processes. The monitoring in industrial systems represents an important economic objective. To guarantee the safety and the continuity in production, exploitation and to record the useful events with the feedback experience for the curative maintenance. One of the possible faults that occur in inverter is the open switch fault. The cost of this schedule can be high, and this justifies the development of fault diagnostic methods.In this work we present a reliable strategy for monitoring and detection of open switch in Space Vector Modulation of voltage source inverter (SVM-VSI) faults using the fuzzy logic approach. The principle of the suggested approach strategy is based on the acquisition of stator currents, to calculate the average absolute values of currents (AAVC), which allows the real-time detection and localization of inverter IGBT open-circuit faults using just the motor phase currents. A model of the system is built using MATLAB/SIMULINK. Simulation results are presented showing the monitoring approach performance under distinct operating conditions. Voir les détails

Mots clés : Monitoring, Detection, fault inverter, SVM, VSI, AAVC