Liste des publications
Theoretical design and performance of InxGa1-xN single junction solar cell
The insertion of optimized Window and a back surface field (BSF) layers on an InxGa1-xN p-n basic single junction (BSJ) solar cell is the chief reason behind the reduction of front and back recombination. In this context, this work is focused on the selection of the suitable parameters including the indium (In) content, thickness and doping concentration for the InxGa1-xN inserted layers, that gives the best photovoltaic performances. At this aim, numerical simulations were performed using the computational numerical modeling TCAD Silvaco-Atlas to design, optimize the InxGa1-xN BSJ and extract the above Window and BSF parameters that enhance the BSJ performances. A short circuit current density ?(J?_sc) of 26.15 mA⁄?cm?^2 , an open circuit voltage ?(V?_oc) value of 0.904 V and a fill factor (FF) value of 79.67 % are obtained under AM1.5G illumination, exhibiting a maximum conversion efficiency (η) of 19.62 %. Other parameters like the external quantum efficiency (EQE), electric field developed, the current density-voltage (J-V) and the power density-voltage (P-V) characteristics are also calculated and plotted for the designed solar cell. Voir les détails
Mots clés : InGaN, solar cell, BSF layer, Window layer, simulation, Silvaco
Robust Fuzzy On–Off Synthesis Controller for Maximum Power Point Tracking of Wind Energy Conversion
Due to the major discrepancy between the exigent demands regarding the electrical energy quality and the irregular nature of the wind, which is characterized by random and instantaneous speed variations, it is vital to determine the optimal operating point that maximizes the efficiency of the obtained electrical energy in the grid from wing generators. The present paper addressed the above-mentioned problem by introducing a fuzzy logic control system in the standard on–off control strategy. The purpose is to maximize the power point tracking of wind energy and to reduce the mechanical loads in which variable wind speed is considered. This idea has the ability to drive the conversion system to its optimal operating point, thereby solving the switching component problem (also referred to as the chattering problem) of the standard on–off control strategy. To examine the validity of the proposed idea, the obtained results are compared with those given by the standard on–off control strategy wherein our method can ensure a better dynamic behavior of the wind energy conversion system. Voir les détails
Mots clés : Wind Energy Conversion System (WECS), Maximum Power Point Tracking (MPPT), Standard and fuzzy on–off controller, Induction generator (IG)
Detection of Broken Rotor Bar Fault in Squirrel Cage Induction Motor using Wavelet Packet Analysis
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. The 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, wavelet paket, analyses
Improved Sliding Mode Controller for Maximum Power Point Tracking of WECS.
Due to the major discrepancy between the exigent demands regarding the electrical energy quality and the irregular characters of the wind, which is characterized by a random and instantaneous speed variation, it is suitable to determine the optimal operating point that maximizes as much as possible the efficiency of the obtained electrical energy in the grid. The present paper deals with the above-mentioned problem by introducing an additional low-frequency component in the standard sliding mode control strategy. The purpose is to maximize the power point tracking of wind energy and to reduce the mechanical loads where the variable wind speed is considered. This idea has the ability to drive the conversion system to the optimal operating point by which the switched component problem, commonly called also the chattering problem of the standard sliding mod control strategy that should be solved. To examine the validity of the proposed idea, the obtained results are compared with those given by the standard sliding mode control strategy wherein our method can ensure a better dynamic behavior of the wind energy conversion system. Voir les détails
Mots clés : Maximum Power Point Tracking MPTT, Standard and Improved Sliding mode controller, Induction Generator IG
Friction stir welding process improvement through coupling an optimizationprocedure and three-dimensional transient heat transfer numerical analysis
The present study deals with the improvement of the Friction Stir Welding process, through the prediction of theoptimal operating conditions, necessary for welding typical Aluminum-Lithium alloy material AA2195-T8. Anoptimization strategy coupled with 3D transient heat transfer computation were used to improve the FSWprocess parameters such as welding velocity, tool rotation velocity, tool diameter and applied force. The optimizationprocedure is based on three criteria: the control of the maximum temperature during FSW; the minimizationof the Heat Affected Zone (HAZ) length and finally the reduction of the total welding energy. Theobtained optimal parameters have given an ideal welding temperature in the workpiece, thereby ensuring goodwelding quality, gain in energy consumption and decrease both the welding time and the HAZ length. Voir les détails
Mots clés : Friction Stir Welding (FSW), Heat transfer, finite volume method, SQP algorithm optimization method
Structural, electronic and optical properties for chalcopyrite semiconducting materials: ab-initio computational study
Investigation of the physical properties of chalcopyrite materials using ab-initio methods have been carried out to simulate a new structure of thin-films photovoltaic cells with high conversion efficiency. The Density Functional Theory calculations have been performed using Wien2k computational package by employing the full-potential linearized augmented plane wave method. Structural and electronic properties of chalcopyrite semiconducting material Copper–Indium–Gallium–Selenium i.e. CuIn1-xGaxSe2 have been investigated using local density approximation for the exchange-correlation potential. The electronic structures and linear optical properties have been studied using both the semi-local Becke-Johnson potential and its modified form i.e. mBJ and TB-mBJ. Computational results are in good agreement with those acquired experimentally. The viability of alloys in realization of ultra-thin-film based (CIGS) solar cells with high performance has been proposed after simulation and analysis study using one of solar cell simulation tools. The studied material exhibits capability to become a promising candidate for fabrication of optoelectronic and photovoltaic devices. Voir les détails
Mots clés : Chalcopyrite, FP-LAPW, optical properties, Thin-films solar cells, wien2k
Particle Swarm Optimization Based Maximum Power Point Tracking Algorithm for Photovoltaic Energy Conversion System
In order to extract the maximum power from PV system, the maximum power point tracking (MPPT) method is one of the most popular and widely used and it has always been applied in photovoltaic energy conversion system. However, this method exhibits fluctuations among the maximum power point (MPP) due to the nature of unpredicted and changes of the environmental parameters. Therefore, it is significant to include an intelligent controller that can track the maximum peak regardless of parameters variations such as: irradiation and temperature. This paper describes the design and development of particle swarm optimization (PSO) based maximum power point tracking (MPPT) algorithm for photovoltaic energy conversion system. The proposed MPPT is simple, flexible, accurate and efficient in maximum photovoltaic power tracking. In this work, MATLAB/Simulink simulation package is used to simulate the performance of the proposed MPPT algorithm. The performance of the proposed PSO algorithm is evaluated by comparing it with the conventional P&O method in terms of tracking speed and accuracy. The simulation results demonstrate that the tracking capability of the PSO algorithm is more efficient, comparing to the traditional one, particularly under parameters variation conditions. Voir les détails
Mots clés : Photovoltaic systems, Maximum Power Point Tracking (MPPT), Particle Swarm Optimization (PSO), perturb and observe (P&O)
Effect of root pass filler metal on microstructure and mechanicalproperties in the multi-pass welding of duplex stainless steels
This paper is focused on the estimation of the effect of root pass chemical composition, in multi-pass GTA Weldments, onmicrostructure and mechanical properties of duplex stainless steel welds.We used two different fillermetals, the super duplex ER2594 and duplex ER 2209. Microstructures of different passes of welded joints are investigated using optical microscope andscanning electron microscope. The relationship between mechanical properties, corrosion resistance, and microstructure ofwelded joints is evaluated. It is found that the tensile and toughness properties of the first weldment, employing the combinationof ER 2594 in the root pass and ER 2209 in the remaining, are better than that of the second weldment employing ER 2209 allpasses, due to the root pass grains refinement and its alloy elements content as chromium Cr and nitrogen N. The microstructureindicates the presence of austenite in different forms on the weld zone of ER 2209, same in the case of ER 2594, but with highercontent and finer grains size, in particularWidmanstätten austeniteWA. Potentiodynamic polarization tests of the first weld metalevaluated in 3.5% NaCl solution at room temperature have been demonstrated a corrosion resistance higher than that of thesecond weld metal. This work addressed the improvement of the corrosion resistance using appropriate filler metal withoutgetting any structural heterogeneity and detrimental changes in the mechanical properties. Voir les détails
Mots clés : Gas tungsten arc welding (GTAW), duplex stainless steel, Root pass, Filler metal, Microstructure and mechanical properties
Design and real time implementation of sliding mode supervised fractionalcontroller for wind energy conversion system under sever working conditions
Wind energy conversion system (WECS) is increasingly taking the place to be the most promised renewablesource of energy, which obliges researchers to look for e?ective control with low cost. Thus, this paper proposesto build a suitable controller for speed control loop to reach the maximum power point of the wind turbine undersever conditions and to ensure the stability of the outer voltage regulation loop to meet high range of loadvariations. In literature, a major defect of the well-used conventional PI controller is the slow response time andthe high damping. Nowadays, intelligent controllers have been used to solve the drawbacks of the conventionalones but they demand high speed calculators and expensive cost. Moreover, many solutions proposed thefractional order PI controller (FO-PI) by extending the order of integration from integer to real order. The FO-PIcontroller presents also some weakness in steady state caused by the approximation methods. The idea of thispaper is to propose a Sliding Mode Supervised Fractional order controller (SMSF) which consists of conventionalPI controller, FO-PI controller and sliding mode supervisor (SMS) that employs one of the controllers to ensuregood steady and transient states. WECS laboratory prototype is built around real-time dSPACE cards andevaluated to verify the validity of the developed SMSF. The results clearly ful?ll the requirements, con?rm itshigh performance in steady and transient states and demonstrate its feasibility and e?ectiveness. Voir les détails
Mots clés : Maximum Power Point Tracking (MPPT), Wind Energy Conversion System (WECS), PI controller, Fractional order PI controller, Sliding mode control, Direct power control
A Fuzzy Logic Based Approach for the monitoringof Open Switch Fault in a SVM Voltage SourceInverter fed Induction Motor Drive
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