Liste des publications
Optimal control based RST controller for maximum power point tracking of wind energy conversion system
This paper presents an LQ optimal control based RST controller for maximum power tracking in a wind energy conversion system (WECS) connected to the electrical grid through a back-to-back converter. Input-output discrete WECS model has been used to implement the input-output optimal control approach. The performance criterion has two terms: the first one is involved for maximum power tracking and the other one for the mechanical fatigue loading (control input) minimization. The obtained simulation results with the considered control and a variable wind profile show an adequate dynamic of the considered conversion system. Voir les détails
Mots clés : wind energy conversion system, Induction generator (IG), LQ optimal control, RST controller
Energy storage based on maximum power pointtracking in photovoltaic systems: A comparisonbetween GAs and PSO approaches
In this paper, a comparison between GAs and PSO Approaches is considered to select andgenerate an optimal duty cycle which varies with photovoltaic parameter in order toextract the maximum Power from Photovoltaic System using real values of temperatureand insolation. The energy storage has very important role in renewable energy. To illustratethe energy storage, we have used a battery type lead-acid simulated in Matlab/Simulink. The obtained simulations results show the effectiveness and the robustness ofthe proposed approaches. Voir les détails
Mots clés : Photovoltaic systems, Chopper, MPPT, PSO, GAs, Energy storage
On-Off control based particle swarm optimization for maximum power point tracking of wind turbine equipped by DFIG connected to the grid with energy storage
In this paper, particle swarm optimization (PSO) is proposed to generate an On-Off Controller. On-Off Control scheme based maximum power point tracking is proposed to control the rotor side converter of wind turbine equipped with doubly fed induction generator connected to the grid with battery storage. The Grid Side Converter (GSC) is controlled in such a way to guarantee a smooth DC voltage and ensure sinusoidal current in the grid side. Simulation results show that the wind turbine can operate at its optimum power point for variable speed and power quality can be improved. Voir les détails
Mots clés : DFIG, Energy storage, Maximum Power Point Tracking, On-Off Control, Particle Swarm Optimization (PSO)
Design and real?time implementation of an adaptive fast terminalsynergetic controller based on dual RBF neural networks for voltagecontrol of DC–DC step?down converter
In this study, an improved Adaptive Fast Terminal Synergetic Controller (AFTSC) using Dual Radial Basis Function (RBF)Neural Networks (NNs) for output voltage control of an uncertain DC/DC step-down converters is proposed. Using theconsidered AFTSC, the with new manifold proposed here enables the DC/DC step-down converter’s state variables to trackthe preferred reference voltage in presence of disturbances from any initial condition with proper precision and limited time.To rendering the design more robust, a sort of dual RBFNNs are utilized to approximate in real-time unknown converternon-linear dynamics and reduce the modeling error without calling upon usual model linearization and simplifcations. Thestability of the closed-loop system is assured by means of the Lyapunov method. Considering the PWM DC–DC step-downconverter as an example, the considered adaptive RBFNN-FTSC law is studied in detail and implemented on a dSPACEds1103 card. All the simulation and experimental results illustrate the efciency and feasibility of the suggested controller. Voir les détails
Mots clés : Synergetic control (SC), Radial basis function neural network (RBFNN), · Fast terminal technique, Limited time, DC/DC step-down converter
A novel nature-inspired maximum power point tracking (MPPT) controller based on ACO-ANN algorithm for photovoltaic (PV) system fed arc welding machines
In this paper, a metaheuristic optimized multilayer feed?forward artificial neural network (ANN) controller is proposed to extract the maximum power from available solar energy for a three-phase shunt active power filter (APF) grid connected photovoltaic (PV) system supplying an arc welding machine. Firstly, in order to improve the maximum power point (MPP) delivered by PV arrays and to overcome the drawbacks in the conventional MPPT method under irradiation variation, a hybrid MPPT controller is designed, in which the input parameters include the PV array voltage and current, and the output parameter is the duty cycle of the DC/DC boost converter. The proposed approach abbreviated as ANN-ACO MPPT controller is based on an ant colony optimization (ACO) algorithm which is useful to train the developed ANN and to evolve the connection weights and biases to get the optimal values of duty cycle converter corresponding to the MPP of a PV array. Secondly, aiming to meet the various grid requirements such as power quality improvement, distortion free signals etc., a three-phase shunt APF is utilized, and a direct power control algorithm is designed for distributing the solar energy between the DC-link capacitor, arc welding machine and the AC grid. Finally, the performance of proposed control system is confirmed by simulation tests on a 12.2 kW PV system. Both simulation and experimental results have demonstrated that the deigned ANN-ACO MPPT controller can provide a better MPP tracking with a faster speed and a high robustness with a minimal steady-state oscillation than those obtained with the conventional INC method. Also, with the use of a three-phase shunt APF, all the power fluctuations from the arc welding machine disturbances are damped out and the output active and reactive power become controllable. Voir les détails
Mots clés : Solar Photovoltaic (PV) system, DC/DC boost converter, three-phase shunt APF, Hybrid ACO-ANN MPPT control, Feed-forward artificial neural network (ANN), Ant Colony Optimization (ACO) algorithm, Arc welding machine
A Robust Adaptive Fuzzy Fast Terminal Synergetic Voltage Control Scheme for DC/DC Buck Converter
In this paper, an adaptive fuzzy fast terminal synergetic voltage control scheme for DC/DC buck converter is proposed based on recently developed synergetic theory and a terminal attractor method. The advantages of presented synergetic control include the characteristics of finite time convergence, insensitive to parameters variation and chattering free phenomena. Rendering the design more robust, fuzzy logic systems are used to approximate the unknown parameters in the proposed controller without calling upon usual model linearization and simplifications. Taking the DC/DC buck converter in continuous conduction mode as an example, the algorithm of proposed synergetic control is analyzed in detail. All the simulation results demonstrate the effectiveness and the high dynamic capability of the proposed AF-FTSC control technique over the FTSC strategy. Voir les détails
Mots clés : synergetic control, fuzzy logic system; terminal technique; finite time convergence; DC/DC buck converter.
Fractional-Fuzzy PID Control Approach ofPhotovoltaic-Wire Feeder System (PV-WFS):Simulation and HIL-Based ExperimentalInvestigation
The utilization of solar photovoltaic (PV) generator as a power source for wire feedersystems (WFSs) of arc welding machines is one of the promising domains in solar PV applications. Thisarticle proposes a new type of welding WFS and investigates the PV penetrated energy systems. Theproposed system comprises of a solar PV generator, a DC/DC buck converter, and a permanent magnet DC(PMDC) motor. The power of the proposed standalone solar photovoltaic-wire feeder system (PV-WFS)can be widely improved using an intelligent fractional-order fuzzy proportional integral derivative (FOFuzzy-PID) regulator based on perturbing and observe (P&O) MPPT method. In this article, a FO-FuzzyPID regulator is also designed for a PMDC motor driven welding WFS system. Which will then control thewire feed rate of the welding WFS system. Furthermore, the dynamic reaction of the proposed solar PVWFS depends on the coefficients of these FO-Fuzzy-PID regulators, which are adjusted by a meta-heuristictuning algorithm based on particle swarm optimization (PSO) technique. The proposed strategy is testedusing MATLAB simulations and experimentally verified in real-time on a Hardware-in-the-loop (HIL)testing platform using a dSPACE®1104 board-based laboratory setup. Simulation and experimental resultsare acceptable and demonstrate the effectiveness, precision, stability, and dynamic reaction of the suggestedoptimized wire feeder regulating system and the considered intelligent P&O MPPT technique. Voir les détails
Mots clés : Buck converter, fractional-order fuzzy PID regulator, MPPT technique, PSO algorithm, PV module, wire feeder system (WFS).
Characterization and analysis of novel natural cellulosic fiber extracted from Strelitzia reginae plant
The purpose of this study is to evaluate in detail the usability of new cellulosic fibers extracted from the stem of the plant Strelitzia reginae, as a potential reinforcement for polymer composites. The morphological, physical, thermal, and mechanical properties of fibers were addressed for the first time in this paper. Both untreated and alkali-treated fibers were characterized, using scanning electron microscopy (SEM), Fourier-transform infrared, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), optical microscope, and X-ray diffraction (XRD) and applying tensile test for determining the mechanical behavior. For both fiber treated at one hour (T1H) and at four hours (T4H), the stem anatomy and fiber SEM micrographs showed a strong presence of fiber cells. Thermogravimetry and DSC showed that the fiber was thermally stable up to 233°C for untreated fiber, 254 and 240°C, respectively, In single-fiber tensile tests, it was observed that the fibers extracted from the stem of Strelitzia reginae were strong. The mean values of Young’s modulus exhibited by untreated fibers and treated (T1H) and (T4H) are, respectively, 9.89 GPa, 12.08, and 18.39 GPa. Also mean values of tensile strength are 271.79, 306.23, and 421.39 MPa. The XRD reveals the presence of cellulose with a Crystallinity Index of 70% for raw fiber and 72% for the treated one. Fourier-transform infrared analysis well demonstrated the effect of chemical treatment. It can be concluded from the results of all above experiments that the Strelitzia reginae fibers (SR) could serve as a possible reinforcement in composite materials. Voir les détails
Mots clés : natural fibers, Biocomposite, Surface analysis, SEM, FT-IR, thermal analysis, TGA, XRD, DSC
Synthesis, Characterization, and Photocatalytic Activity ofBa-Doped BiFeO3 Thin Films.
Abstract: In the present paper, Bi1-xBaxFeO3 (BBFO) thin films (where x = 0, 0.02 and 0.05) wereprepared by a combined sol-gel and spin-coating method. The influence of Ba substitutions on thestructural, microstructural, optical properties, and photocatalytic activity of BiFeO3 thin films hasbeen studied. X-ray diffraction pattern correlated with FTIR analysis results confirms that all thefilms have a perovskite structure of rhombohedral symmetry with an R3m space group. Atomicforce microscopy (AFM) and scanning electron microscopy (SEM) were used to investigate thesurface morphology and reveals microstructural modifications with the increase in Ba concentration.The optical properties show that the band gap is narrowed after doping with Ba ions and decreasesgradually with the increase of doping content. The photocatalytic investigations of depositedfilms revealed that Ba doping of BFO material leads to the enhancement of photocatalytic response.The present data demonstrates that Bi1-xBaxFeO3 (BBFO) thin films can be used in photocatalyticapplications. Voir les détails
Mots clés : perovskites; films; optical properties; doped BaTiO3; photocatalytic activity
Chemical sensor array modeling. Quartz crystal microbalance sensors.
The primary objective of the paper is to develop Gibbs- Duhem like equations for the interactions between Quartz Crystal Microbalance (QCM) based sensor array and a mixture of vapors. These differential equations connect the variations of the sensors partial sensitivities or the sensors response with the gas mixture components concentrations. Furthermore, Thermodynamic models in the case of conducting polymer sensors, whose multi-component adsorption follows the generalized adsorption model of Langmuir have been deduced, these are differential equations that connect the adsorption entropies to the selectivities of the sensors and coefficients of standardization at constant temperature Voir les détails
Mots clés : chemical sensor array, Quartz Crystal Microbalance sensors, gas mixture, modeling, equations of Gibbs-Duhem, adsorption entropy