Automatique
Application of Direct Power Control in Wind EnergyConversion System
This paper describes the performance evaluation of thedirect power control for a three-phase pulse with modulationinverter fed by a variable speed wind energy conversion system.This, to ensure a maximum power point tracking of a wind.Proposed direct power control strategy is implemented in the d-qreference frame. The system modeling and control scheme areimplemented on Matlab/Simulink. The simulation results show thatthe use of the direct Power Control provide nearly sinusoidal inputwave form current, constant switching frequency operation,regulation of unity power factor in the connection of the grid sideconverter with the grid and the maintain of the DC-link voltageconstant. Finely, the results verify the validity and effectiveness ofthe proposed control. Voir les détails
Mots clés : Renewable energies, wind energy conversion system, Direct power control, simulation
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
Composite adaptive dynamic surface control of nonlinear systems in parametric strict-feedback form
In this paper, a composite adaptive dynamic surface control scheme is developed for a class of parametric strict-feedback nonlinear systems. The proposed composite adaptation law uses both the surface error and the estimation error to update the parameters. In addition, by using the dynamic surface control technique, the problem of the explosion of complexity in the adaptive backstepping design is avoided. It is proved that the proposed scheme guarantees uniform ultimate boundedness of all signals in the closed-loop system with arbitrary small surface error by adjusting the design parameters. Simulation results demonstrate the effectiveness of the proposed approach for an electrohydraulic actuator system. Voir les détails
Mots clés : Composite adaptation law, direct and indirect adaptive control, dynamic surface control, Lyapunov stability, parametric strict-feedback nonlinear systems
Modélisation Statistique pour l’Evaluation de l’Energie Eolienne
L’intérêt de ce travail est l’estimation et l’évaluation du potentiel éolien dans la ville de Annaba. Les données mensuelles et annuelles de la vitesse du vent, mesurées à 3 m de hauteur et recueillies par la station météorologique de l'aéroport international de Rabah-Bitat, sont rtraitées par une simulation en utilisant une fonction de distribution de Weibull. La fonction de densité de Weibull est utilisée en vue de l’évaluation du potentiel éolien mensuelle et saisonnière du vent à la hauteur 16m. Une analyse statistique des caractéristiques du vent ainsi que l'extrapolation des paramètres de Weibull sont présentées. Voir les détails
Mots clés : Energie éolienne, vitesse du vent, distribution de Weibull, modélisation statistique
Direct Power Control of DFIG Used in Wind EnergyConversion System
The problems caused by traditional systems on the environment of energy production havesucceeded, in the immediate, the utilization the renewable energies for to preserve theenvironment and to satisfy the energy. So, thanks to the encouragement of governments andthe global orientations, the development of wind energy has grown significantly due to thediversity of exploitable areas and to the relatively attractive costs. Therefore, the wind energyis becoming one of the most important renewable energy sources. Indeed, variable speedWind Energy Conversion System (WECS) have become the industry standard because oftheir advantages over fixed speed ones such as improved energy capture, better power quality.The WECS described in this work is show by figure 1. He includes the wind turbine, gearbox,DFIG, and back-to-back converters whereas the stator winding is fed by back-to-backbidirectional converter. In this system, the wind energy is transmitted Through theturbine to the three-phase DFIG. This energy is transmitted directly through a bridgerectifier and inverter to the electrical network. Voir les détails
Mots clés : Wind energy conversion system; Doubly Fed Induction Generator; Maximum power point tracking; Simulation
Grey Wolf Optimization of Fractional PID controllerin Gas Metal Arc Welding process
Gas metal arc welding (GMAW) plays the greatimportance in the welding industry. This paper presents a greywolf optimization (GWO) of fractional PID controller in orderto optimize arc length and arc current in the GMAW process.Firstly, fractional PID control of gas metal arc welding system isproposed, wherein the arc length and current of welding processare controlled, then the Grey Wolf Optimization is introduced tosolve multi-objectives functions of GMAW in order to find theoptimal parameters of fractional PID controller. The obtainedresults are compared with those given by fractional PIDcontroller in which our proposed method can ensure a betterdynamic behavior of the GMAWprocess. Voir les détails
Mots clés : GMAW, MIMO system, GWO, Fractional PID controller
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
Control of Matrix Converter Fed Induction Motor Drive
This paper presents a variable speed control of the squirrel induction machine fed by a three-phase matrix converter. Principle of vector control for induction motor and vector control strategy in synchronous reference frame are described. The use of matrix converter allows the availability of better switching devices, bi-directional power flow and sinusoidal input and output waveform. Also, the advantages of matrix converter are combined with the advantages of the field oriented control technique where Venturini algorithm is applied. We study the operation of the motor in the four regions of speed-torque plane. At this effect, the simulation results of the whole system are carried out with four quadrants of motor operations and the performance results obtained are presented and analyzed. A good performance of induction motor fed by a matrix converter is proved. Voir les détails
Mots clés : matrix converter, induction motor, vector control, modelling, Simulation.
Power Control of DFIG Driven by Matrix ConverterUnder Super and Sub Synchronous OperationModes
In this paper, we present the modeling and control of the wind energy conversion systemsbased on the doubly fed induction generator fed by AC/AC matrix converter. Firstly, wedeveloped the models of the different elements of the conversion chain. After, we consider thevector control strategy of the active and reactive powers in order to ensure an optimum operation.Finally, the dynamic model of a doubly fed induction generator and wind turbine grid connectedsystem is determined in the d-q synchronous reference frame.Therefore, the powers control isverified using software Matlab/Simulink. The behaviours of the sub-synchronous and supersynchronous operation modes is presented and discussed. The results prove that the power controlstrategy is well adapted to this kind of system. Voir les détails
Mots clés : wind systems, doubly fed induction generator, Bidirectional DC-DC Converter, Variable Speed Wind Turbine
Adaptive backstepping control using combined direct and indirect σ-modification adaptation
In this paper, by using the dynamic surface control technique, an adaptive backstepping controller using combined direct and indirect σ-modification adaptation is proposed for a class of parametric strict-feedback systems. In this approach, a σ-modification parameter adaptation law that combines direct and indirect update laws is proposed. At first, the x-swapping identifier with a gradient-type update law is presented for a class of parametric strict-feedback nonlinear systems. Next, the main steps of the controller design for a class of nonlinear systems in parametric strict-feedback form are described. The closed-loop error dynamics is shown to be globally stable by using the Lyapunov stability approach. Finally, simulation results for a single-link flexible-joint robot manipulator are given to illustrate the tracking performance of the proposed adaptive control scheme. Voir les détails
Mots clés : Backstepping control, direct and indirect adaptive control, adaptive dynamic surface control, Lyapunov stability, flexible joint manipulators