Liste des documents
Finite-Set Model Predictive Decoupled Active and Reactive Power Control for Wind Energy Systems
This paper introduces a novel approach for direct power control of three-phase voltage source inverter in grid connected distribution wind energy systems. In this approach, the control of active and reactive power is based on finite-set model predictive control strategy. The proposed strategy has the simplicity of the direct power control technique and doesn’t require any current control loops. To meet the future generation of Permanent magnet synchronous generator wind turbines, a DC-DC boost converter is proposed at the machine-side to simplify the control and potentially reduce the cost of the wind energy system. The wind generation system requirements, such as maximum energy harvesting and regulation of grid active and reactive power are expressed as cost functions. Best switching states are selected and applied to the power converters during each sampling interval based on the minimization of cost functions. The feasibility of the proposed configuration and control scheme are verified through dSPACE 1104 experiments on a low power prototype. Voir les détails
Mots clés : Maximum Power Point Tracking, Finite-set model predictive control, Permanent Magnet Synchronous generator, Wind energy system
Enhanced Operation of Grid Connected Wind Energy Conversion System
In this paper, a novel discrete time predictive control strategy applied to a direct matrix converter (DMC)which allows an optimal control of a variable speed permanent magnet synchronous wind generator ispresented. The commutation state of the DMC in the subsequent sampling time according to anoptimization algorithm given by a simple cost functional and the discrete system model without the needfor any additional modulation scheme or internal cascade control loops. The control goals are regulationof the rotor torque and stator flux of the PMSG according to an arbitrary references established based onthe maximum power point tracker (MPPT), and also a good tracking of the output reactive power to itsreference ensures unitary power factor and improve the system stability. The complete control system hasbeen developed, analyzed, and validated by time domain simulation. The simulation results exhibit goodsystem performance and the efficiency control enhancement of the wind energy conversion system(WECS) using the direct matrix converter structure. Voir les détails
Mots clés : Finite Set Model Predictive Control(FS-MPC), Permanent Magnet Synchronous Generator (PMSG), Wind Energy Conversion System (WECS), Maximum Power Point Tracking (MPPT) Control, Direct Matrix Converter (DMC), Grid Connected
Real Time Implementation of Grid-connection controlusing Robust PLL for WECS in Variable SpeedDFIG-based on HCC
This paper presents the experimental real timeimplementation of a grid-connection field-oriented control (FOC)for wind turbine based on a doubly fed induction generator(DFIG). A control law is synthesized using a hybrid FOCHysteresisCurrent Controller (HCC) in Rotor side converter(RSC) and the stator is connected to grid via robust PLL (phaselocked loop). The regulation is achieved below the synchronousspeed (Hypo-synchronous mode). The implementation is realizedusing dSPACE1104 single board card control and acquisitioninterface. The obtained results of the proposed control presenthigh performance in steady and transient states with low THD ofthe stator injected current to the grid (<5%). Voir les détails
Mots clés : Doubly fed induction generetor (DFIG), Field oriented control (FOC), Hysteresis current controller (HCC), Rotor side converter (RSC), dSPACE1104
Experimental Design of Stand-alone Field Oriented Control for WECS in Variable Speed DFIG-based on Hysteresis Current Controller
This paper presents the experimental design of a stand-alone field-oriented control (FOC) for wind turbine based on a doubly fed induction generator (DFIG). The control law is synthesized using a hybrid FOC-Hysteresis current controller (HCC) in Rotor side converter (RSC) and the stator is connected to the resistive load via rectifier (nonlinear load). The regulation is achieved below the synchronous speed (Hypo-synchronous mode). The implementation is realized using dSPACE1104 single board control and acquisition interface. The obtained results of the proposed control present high performance in steady and transient states. Voir les détails
Mots clés : Doubly fed induction generetor (DFIG), Field oriented control (FOC), Hysteresis current controller (HCC), Rotor/Stator side converter (RSC/SSC), dSPACE1104
Predictive Control of Power Electronics Converters in Wind Energy Systems
In order to make a wind power generation truly costeffective and reliable, an advanced control techniques must beused. In this paper, we develop a new control strategy usingModel Predictive Control (MPC) approach for permanentmagnet synchronous generator based wind turbine system. Theproposed control law is based on two points: MPC-based torquecurrentcontrol loop for the generator-side converter to reach themaximum power point of the wind turbine, and MPC-basedcurrent control loop for the grid-side converter to satisfy the gridcode and to help improve system stability. A small-scale windturbine system prototype was built and tested in the laboratory,and the experimental results are provided to verify the validity ofthe developed control methods, MPPT algorithm andperformance of the system operations. Voir les détails
Mots clés : finite-set model predictive control (FSMPC), Permanent Magnet Synchronous Generator (PMSG), Wind Energy Conversion System (WECS), Maximum Power Point Tracking (MPPT) Control, Grid Connected, experimental validation
Phased array B-scan image enhancement based oncontinuous wavelet transform and Shannon energyalgorithm
In this work, we describe a novel algorithm for ultrasonic phased array signalsenhancement, based on continuous wavelet transform using the Mexican Hat wavelet mother(CMHWT) and normalized Shannon Energy (SE). The use of signal processing algorithms indefect detection gives generally very satisfactory results. Time–frequency analysis methods aremainly used to improve the defects detection resolution. Performance improvement is confirmedwhen the proposed approach is tested with B-scan signals containing delamination closer to thefront face. This work has successfully demonstrated that the proposed method can improve thequality of ultrasound B-scan signal. Voir les détails
Mots clés : phased array, Defects enhancement, CWT, Shannon energy, Mexican hat wavelet
Detection and classification of steel defects using machine vision and SVM classifier
the importance of quality control of steel products is increasing day by day in the manufacturing industrial systems because it offers the possibility of knowing the state of the products without stopping the production line which allows the control of a defect before it becomes a complex problem and avoiding production losses. Human quality control of steel products remains tedious, fatiguing, bit fast, bit robust, dangerous or impossible, therefore the use of automated vision system can significantly improve the quality inspection process, because the machine vision technology can overcomes the majority of manual inspection problems cited above and provide an interesting solution especially, with the impressive increasing of computing power of today's computers and the good quality of images that offer the current cameras.The main objective of this research is to propose an efficient control system based on machine vision technology and SVM classifier to classify different types of steel defects. Voir les détails
Mots clés : Defects steel, machine vision, pattern recognition, HOG, GLCM, SVM classifier
Investigation of Polycrystalline silicon TFT’s electrical characteristics
Low-temperature polycrystalline silicon thin film transistors (poly-Si TFT’s) on plastic substrate have been studied because of their high performance in Active Matrix Liquid Crystal Displays (AMLCD’s) and Active Matrix Organic Light-Emitting Diode (AMOLED) applications. The purpose of this work is to simulate the impact of varying the electrical and physical parameters (the interface states, active layer’s thickness and BBT model) in the transfer characteristics of poly-Si TFT to extract the electrical parameters like threshold voltage, mobility and to evaluate the device performance. The device was simulated using the ATLAS software from Silvaco. The results show that the electrical and physical parameters of poly-Si TFT affect significantly its transfer characteristics. Voir les détails
Mots clés : Poly-Si TFT, TCAD-ATLAS, electrical characteristics
SIMULATION DE L’INTENSITE DU FLUX SOLAIRE CONCENTRE RECUS AU NIVEAU DE L’ABSORBEUR
La plus grande ressource d’énergie techniquement accessible sur la planète est disponible dans les régions désertiques. Nous allons étudier plus particulièrement l’énergie solaire qui permet de récupérer la chaleur du rayonnement solaire au sein d’un fluide, cela par la conversion de l’énergie noble (énergie solaire) en énergie thermique par la mise en œuvre des capteurs solaires thermiques. Le présent travail propose une étude numérique des performances optiques d’un concentrateur cylindro-parabolique à eau, nous avons simulé la distribution du flux solaire autour du tube absorbeur à l’aide d’un logiciel SOLRACE en utilisant la méthode de Monté Carlo Ray-tracing. Voir les détails
Mots clés : Concentrateur cylindro-parabolique, Flux solaire, Simulation.
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