Liste des publications
Maximum Power Point Tracking of Wind Energy Conversion System Using Multi-objective grey wolf optimization of Fuzzy-Sliding Mode Controller
Ongoing electricity demand and the increasing growth of population have become necessary to provide alternative and clean sources of energy. Wind energy is one of the most important sustainable energies but the irregular characters of the primary source, which is characterized by a random wind speed variation, makes the process of control is difficult in order to maximize the power. This paper presents a multi objective grey wolf optimization (MOGWO) of fuzzy sliding mode controller in order to maximize the power captured by wind turbine; meanwhile, the mechanical loads are alleviated for variable speed wind energy conversion system (VS-WECS); firstly, Fuzzy logic theory based sliding mode control is developed by collecting the sliding surface data to reduce the chattering effect caused by the SMC, then the Grey Wolf Optimization is introduced to solve multi-objectives functions of WECS which are extracting the maximum power and alleviation the mechanical loads in order to find the optimal parameters of Fuzzy-Sliding mode controller to drive the conversion system to the optimal operating point. The obtained results are compared with those given by Sliding mode controller and Fuzzy-Sliding mode controller in which our proposed method can ensure a better dynamic behavior of the WECS. Voir les détails
Mots clés : Wind Energy Conversion System WECS, Maximum Power Point Tracking MPTT, Sliding mode control, fuzzy logic control, MO-GWO
Valuation of mill scale as iron pigments for painting anticorrosive.
The mill scale is a steelmaking byproduct. This work focuses on the valuation of the steel waste and its transformation to a usable product in the field of anti-corrosion paints. These iron oxides have been examined as a pigment and corrosion inhibitor in two types of paints with different concentrations (1 %, 3 %, 7 %, and 15 %) to determine the best formulation. Their properties were compared to that of an anticorrosion paint trademark based on iron oxide. For this purpose various techniques of mechanical and physical-chemical analysis were used; grinding is applied to pieces of mill scale for very fine powders (< 32 μm); the particle size of the milled scale analysis, to determine their particle size distribution; a primary electrochemical method used to evaluate the performance and scale vis-à-vis the phenomenon of corrosion behavior, and a UV-Visible spectroscopic method for determining the concentration of total dissolved iron. The experimental results showed that the anti-corrosion properties or rather inhibition efficiency increases with increasing concentration of the mill scale in the tested paints. Voir les détails
Mots clés : mill scale, corrosion inhibitor, spectroscopic, electrochemical analysis
Fuzzy-PSO controller design for maximum power point tracking in photovoltaic system
Photovoltaic power generation system becomes increasingly important, highly attractive as a clean and renewable energy sources, widely used today in many applications. Recently, researchers have strongly promoted the use of solar energy as a viable source of energy due to its advantages and which it can be integrated into local and regional power supplies. The P–V curve of photovoltaic system exhibits multiple peaks under various conditions of functioning and changes in meteorological conditions which reduces the effectiveness of conventional maximum power point tracking (MPPT) methods and the Particle swarm optimization (PSO) algorithm is considered to be highly efficient for the solution of complicated problems.In this paper, the application of this approach based MPPT algorithm for Photovoltaic power generation system operating under variable conditions is proposed to optimize and to design an intelligent controller comparing to conventional one. PSO Approaches is considered to select and generate an optimal duty cycle which varies with photovoltaic parameters in order to extract the maximum Power. Simulation results show that the proposed approach can track the maximum power point faster and can improve the performance of the system compared to the conventional method. Voir les détails
Mots clés : Particle Swarm Optimization (PSO), photovoltaic System, Boost, PWM, MPPT, FLC
Particle Swarm Optimization Backstepping Controller for a Grid-Connected PV/Wind Hybrid System.
The current paper investigates Backstepping controller using Particle Swarm Optimization for Photovoltaic "PV"/Wind hybrid system. The tested system was connected to the grid by three-phase inverter commissioned to address current depending on the grid parameters and still deliver its reactive power to zero. Backstepping control is a recursive methodology that uses Lyapunov function which can ensure the system stability. The best selection of Lyapunov function gains values should give a good result. In most of the literatures, the choice was based on the expertise of the studied system using hurwitzienne method considered as heuristic choice. The aim of this work is to propose an optimization using a powerful method commonly called Particle Swarm Optimization "PSO" able to calculate the gains values depending on the grid parameters by minimizing a selected criterion. The simulation results show that the PSO Backstepping controller gives good results shown in the current injected to grid with a small harmonic distortion despite climate change in the wind speed and the irradiation, which also shows the robustness of the applied control. Voir les détails
Mots clés : PV/Wind Grid-Connected, MPPT, Backstepping Controller, PSO, Matlab/Simulink
Quantum and conversion efficiencies optimization of superstrate CIGS thin-films solar cells using In2Se3 buffer layer
In this present contribution, AMPS-1D device simulator is employed to study the performances of superstrate SLG/TCO/p-Cu(In,Ga)Se2(CIGS)/n-ODC/n-In2Se3/Metal thin film solar cells. The impact of theTCO and Metal work functions on the cell performance has been investigated. The combination of optical transparency and electrical property for TCO front contact layer is found to yield high efficiency. The obtained results show that the TCO work function should be large enough to achieve high conversion efficiency for superstrate CIGS solar cell. Nevertheless, it is desirable for Metal back contact layer to have low work function to prevent the effect of band bending in the n-In2Se3/Metal interface. Several TCOs materials and metals have been tested respectively as a front and back contact layers for superstrate CIGS solar cells. An efficiency of 20.18%, with Voc ≈ 0.71 V, Jsc ≈ 35.36 mA/cm2 and FF ≈ 80.42%, has been achieved with ZnSn2O3-based as TCO front contact layer. In the case of SnO2:F front contact and indium back contact layers, an efficiency of 16.31%, with Voc ≈ 0.64 V, Jsc ≈ 31.4 mA/cm2 and FF ≈ 79.4%, has been obtained. The present results of simulation suggest an improvement of superstrate CIGS solar cells efficiency for feasible fabrication. Voir les détails
Mots clés : Cu(InGa)Se2 material, Superstrate solar cells, Transparent conducting oxides, Barrier height, AMPS-1D
Rolling bearing faults diagnosis based on empirical mode decomposition: Optimized threshold de-noising method
The faults of rolling bearings frequently occur in rotary machinery, therefore the rolling bearings fault diagnosis is a very important research project. The vibration signal is usually noisy and the information about the fault in the early stage of its development can be lost. A threshold de-noising method based on Empirical Mode Decomposition (EMD) is presented in this paper. Firstly, the signal is decomposed into a number of IMFs using the EMD decomposition. Secondly the algorithm based on the energy to determine the trip point is designed for IMF selection, then, by comparing the energy of the selected IMFs with excluded IMFs, singular selected IMFs are treated with soft threshold function, and finally the de-noised signal is obtained by summing up the selected IMFs, it is proved that the best IMFs can be summed up and properly de-noised by the proposed method. The results show the effectiveness of the proposed technique in revealing the bearing fault impulses and its periodicity and amelioration the sensibility of scalar indicator for real rolling bearing vibration signals Voir les détails
Mots clés : bearing fault detection, EMD, threshold Denoising, IMF selection, Singular IMF
EVOLUTION OF THE MICROSTRUCTURAL PARAMETERS OF COLD WORK Ti-6-Al-4V ALLOY.
AbstractThe aim of this work is to investigate cold worked Ti-6Al-4V (α+β) alloy. The alloy was examined by X-ray diffraction using Rietveld refinement method. MAUD software (Materials Analysis Using Diffraction) was used to analyze the microstructural parameters evolution (crystallite size, root mean square strain (r.m.s) and dislocation density. The Crystallite size is smaller in the β-phase compared to the α-phase. Microstrain and dislocation density are higher in the α-phase than those found in the β-phasefor the as received material. The microstructural parameters of Ti-6Al-4V alloy exhibit typical values of cold deformation state. The results show that the deformation process reducesthe crystallite size (coherent diffraction domains) from 520 to 210 ? in the α-phase. Consequently, the r.m.s increases from 5 E-4to 32 E-4and the dislocation density increases from 2.92 E+10to 4.6 E+11m-2after 85 % thickness reduction. Voir les détails
Mots clés : Ti-6Al-4V alloy, cold working, crystallite size, dislocation density
Modelling of thermodynamics of adsorption on sensor array films : application to the generalized multicomponent adsorption model of Langmuir
In the present study, by using of Gibbs Duhem formalism and simple mathematics, new models, which describe the response of the elements of a sensor array , have been developed .In addition , the thermodynamic ehavior of the interfaces sensor array fims gas mixture has been treated . Finally, the derived models were used for the generalized model of adsorption of Langmuir. Voir les détails
Mots clés : adsorption of Langmuir, Gibbs Duhem equations, intrinsic conducting polymers, modeling, sensor array
STRUCTURAL AND MAGNETIC PROPERTIES OF Fe–Co/Al2O3NANOCOMPOSITE POWDER PRODUCEDBY MECHANICAL ALLOYING
The effect of milling time and addition of elements on the microstructure, magnetic and mechanicalproperties of the Fe–xCo (x = 0, 5, 10, and 20 wt.%) matrix nanocomposite reinforced with 40 wt.%Al2O3 during mechanical alloying is examined. Fe–Al2O3 and Fe–Co–Al2O3 alloys are milled for 5,15, 20, and 30 h and 20 h, respectively. The balance between the welding and fracturing and asteady-state situation is found out in the Fe–Co–40 wt.% Al2O3 nanocomposite after 20 h, due to theCo introduction into the Fe matrix, but not in the Fe–Al2O3 nanocomposite. After 30 h of milling, theaverage crystallite size was 5 nm in the Fe matrix. The lattice strain increased to ~0.64% in the Fematrix after ?30 h of milling and in the binary Fe–20 wt.% Co matrix after 20 h of milling; theaverage crystallite size was 3 nm. The lattice strain increased to ~0.56% for the Fe–20 wt.% Comatrix after ?20 h of milling. The coercive field (Hc) increased from 6.407 to 82.027 Oe, while thesaturation magnetization (Ms) decreased from 20.732 to 15.181 emu/g in the Fe matrix duringmilling. The Hc and Ms are maximum for the binary matrix (20 and 10% Co, respectively) Voir les détails
Mots clés : Fe–Co matrix nanocomposite, alumina, Mechanical Alloying, microstructural evolution, magnetic properties.
Reliability of the High Strength Pipeline Steelunder Corrosion Defect
The demand of energy based on hydrocarbons, such as gas and oil, requires construction of more and more newpipelines. Therefore, the assessment of the remaining life of these pipeline structures became increasingly importantto ensure the continuity of production and distribution operations. The reliability of these industrial facilities islargely conditioned by specific characteristics of each system, by its conditions of use and its environment. Generally,the causes of deterioration of hydrocarbon transportation pipelines are related to the presence of apparent defects(pinholes, cracks, corrosion, etc). This study is aimed to estimate the reliability of pipeline structures. The B31Gmechanical model of degradation was used to assess the probability of failure through dimensions of defects. Voir les détails
Mots clés : Reliability, pipeline, Defects, Mechanical Model