Attous D, “Sliding Mode Controls of Active and Reactive Power of a DFIG with MPPT for Variable Speed Wind Energy Conversion

Abstract: This paper presents the study of a variable speed wind energy conversion system based on a Doubly Fed Induction Generator (DFIG) based on a sliding mode control applied to achieve control of active and reactive powers exchanged between the stator of the DFIG and the grid to ensure a Maximum Power Point Tracking (MPPT) of a wind energy conversion system. The proposed control algorithm is applied to a DFIG whose stator is directly connected to the grid and the rotor is connected to the PWM converter. To extract a maximum of power, the rotor side converter is controlled by using a stator flux-oriented strategy. The created decoupling control between active and reactive stator power allows keeping the power factor close to unity. Simulation results show that the wind turbine can operate at its optimum energy for a wide range of wind speed

Contribution à l’Etude et à la Commande Robuste d’un Aérogénérateur Asynchrone à Double Alimentation

Dans le cadre de la recherche croissante à des nouvelles sources de production d’énergie électrique parmi elles les énergies renouvelables, cette thèse présente une contribution à l’étude et à la commande robuste de l’aérogénérateur asynchrone à double alimentation à pour objectif d’exploiter de l’énergie du vent pour produire d’une énergie propre sans pollution. Tout d’abord, nous avons exposé les modèles mathématiques de chaque élément de l’aérogénérateur (la turbine éolienne et sa commande MPPT + le générateur et sa commande vectorielle). Pour optimisé les gains des régulateurs classiques PI pour obtenir des bonnes performances, nous cherchons à déterminer les coefficients des régulateurs PI utilisés pour la commande vectorielle du générateur asynchrone à double alimentation sans le recours aux méthodes analytiques classiques pour le calcul des ces derniers. Pour ceux-ci nous essayons de développer un algorithme par la méthode d’essaim de particules (PSO) tout en visualisant la fonction objectif (fitness) dont on cherche à minimiser l’erreur dans un système asservi entre le signal d’entrée et le signal de sortie. Les lois de commande classique du type PI appliquées au générateur asynchrone à double alimentation donnent des bons résultats dans le cas des systèmes linéaires à paramètres constants. Pour des systèmes non linéaires où ayant des paramètres non constants, ces lois de commande classique peuvent être insuffisantes car elles sont non robustes. Pour cela on doit faire appel à des lois de commande insensibles aux perturbations et aux cas non linéaires. La commande par mode glissant est par sa nature une commande non linéaire constituent une bonne solution à ces problèmes liés à la commande classique. Dans la dernière partie de cette thèse, nous avons appliqué la commande par mode glissant pour contrôler la puissance active et réactive avec l’utilisation d’un onduleur commandé par la technique SVM pour améliorer la qualité d’énergie électrique pour injecter cet énergie au réseau électrique où la simulation a été effectué sous l’environnement Matlab/Simulink. Les résultats de simulation obtenus par l’application de la commande par mode glissant à l’aérogénérateur asynchrone à double alimentation sont considérablement acceptables

FUZZY SLIDING MODE CONTROLLER FOR DOUBLY FED INDUCTION MOTOR SPEED CONTROL

<p>This paper, presents a Direct Field-Oriented Control (DFOC) of doubly fed induction motor (DFIM) with a fuzzy sliding mode controller (FSMC). Our aim is to make the speed control robust to parameter variations. The variation of motor parameters during operation degrades the performance of the controllers. The use of the nonlinear fuzzy sliding mode method provides very good performance for motor operation and robustness of the control law despite the external/internal perturbations. The chattering effects is eliminated by a particular function "sat" that presents a serious problem to applications of variable structure systems. The fuzzy sliding mode controller is designed in order to improve the control performances and to reduce the chattering phenomenon. In this technique the saturation function is replaced by a fuzzy inference system to smooth the control action. The proposed scheme gives fast dynamic response with no overshoot and zero static error. To show the validity and the effectiveness of the control method, simulation results are performed for the speed control of a doubly fed induction motor. Simulation results showed that improvement made by our approach compared to conventional sliding mode control (SMC) with the presence of variations of the parameters of the motor, in particular the face of variation of moment of inertia and disturbances of load torque. The results show that the FSMC and SMC are robust against internal and external perturbations, but the FSMC is superior to SMC in eliminating chattering phenomena and response time.</p

Effet de la température sur la géométrie et la réactivité en hydrodésazotation (HDN) de la phénanthridine

En présence du catalyseur industriel NiMo/Al2O3, l’activité en HDN de la phénanthridine est d’autant plus grande que la température de la réaction est élevée. Cette relation température-activité serait due à la variation de la conformation de son intermédiaire réactionnel saturé (perhydrophénanthridine) en fonction de la température du milieu réactionnel. Dans ce travail, nous montrons par une étude RMN du carbone 13, que la conformation la plus favorable à l’adsorption de la perhydrophénanthridine sur le catalyseur NiMo/Al2O3 et par suite à sa désazotation (HDN) est la conformation cis-cis, adoptée sous la température de 420°C.Mots clés: HDN; phénanthridine; hydrogénation; conformation; NiMo/Al2O3.When the industrial catalyst NiMo/Al2O3 is used, the HDN activity of phenanthridine becomes higher as the reaction temperature is elevated. This temperature-activity relationship would be due to the variation of its reacting intermediary conformation which is saturated (perhydrophenanthridine) according to the temperature of the medium. In this work, through an NMR of carbon 13 study, we show that the cis-cis conformation is the most favorable for perhydrophenanthridine adsorption when using NiMo/Al2O3 and following an HDN reaction at 420°C.Keywords: HDN; phenanthridine; hydrogenation; conformation; NiMo/Al2O3

FUZZY SLIDING MODE CONTROLLER FOR DOUBLY FED INDUCTION MOTOR SPEED CONTROL

This paper, presents a Direct Field-Oriented Control (DFOC) of doubly fed induction motor (DFIM) with a fuzzy sliding mode controller (FSMC). Our aim is to make the speed control robust to parameter variations. The variation of motor parameters during operation degrades the performance of the controllers. The use of the nonlinear fuzzy sliding mode method provides very good performance for motor operation and robustness of the control law despite the external/internal perturbations. The chattering effects is eliminated by a particular function "sat" that presents a serious problem to applications of variable structure systems. The fuzzy sliding mode controller is designed in order to improve the control performances and to reduce the chattering phenomenon. In this technique the saturation function is replaced by a fuzzy inference system to smooth the control action. The proposed scheme gives fast dynamic response with no overshoot and zero static error. To show the validity and the effectiveness of the control method, simulation results are performed for the speed control of a doubly fed induction motor. Simulation results showed that improvement made by our approach compared to conventional sliding mode control (SMC) with the presence of variations of the parameters of the motor, in particular the face of variation of moment of inertia and disturbances of load torque. The results show that the FSMC and SMC are robust against internal and external perturbations, but the FSMC is superior to SMC in eliminating chattering phenomena and response time

Robust synergetic-sliding mode-based-backstepping control of induction motor with MRAS technique

This paper proposes a new speed control of an induction motor (IM) drive, which is based the combination between the backstepping control (BC) and synergetic-sliding mode controller (SSMC). In addition, it was proposed to use the Model Reference Adaptation System (MRAS) to estimate the IM speed with the aim of reducing speed error and increasing the performance and efficiency of the proposed system. IM has already been considered for many applications, especially traction systems that mainly use proportional-integral controllers. However, such types of controllers do not handle well in the event of a system malfunction. These may reduce the performance of the control system. Therefore, a robust nonlinear control, namely BC-SSMC with MRAS, is proposed. This control relies on combining the advantages of both BC and SSMC to control the IM speed. Also, the MRAS was used to replace the speed sensor with the aim of reducing the periodic maintenance of this sensor and thus reducing the size and cost of the system. The robustness of the BC-SSMC-MRAS was analyzed with respect to the occurrence of system malfunctions, as it is considered the most robust compared to BC. The simulation results performed on the 1.5 kW IM showed the effectiveness of the BC-SSMC-MRAS in enhancing the system durability, reducing the torque ripples and improving the current quality. In all tests performed, the speed overshoot value was improved by 100 % compared to the BC. Also, the torque and flux ripples in the event of a machine malfunction are improved by 50 % and 77.14 %, respectively, compared to the BC. In the speed change test, the response time and steady-state error of speed values were improved by 5.26 % and 67.56 %, respectively. So all these ratios prove the superiority of the BC-SSMC-MRAS over the BC in terms of improving system performance