Unified power flow controller is a power electronics-based device utilised to improve transmission line capacity and control power flow transmitted by power transmission systems. This paper presents the application of the decoupled control strategy to control independently active and reactive power in the event of changes in the step points of the powers. Two types of controllers are used to handle the control strategy proposed: conventional PI regulator and fuzzy logic PI regulator. The fuzzy logic controller must have high performance to handle the problem of adjustment of power decoupling. Also, a three level neutral point controller inverter is used in both series and shunt parts of the UPFC to get multistep voltage wave and improve the power quality.

Le présent article traite le problème de l’échange d’énergie électrique entre des réseaux interconnectés. L’objectif principal est de développer un programme qui permet de déterminer les moments les plus économiques pour l’échange d’énergie électrique entre les réseaux électriques. Pour que ce bénéfice soit encore meilleur, l’échange doit être anticipé par une répartition optimale de la charge pour chaque réseau électrique. Pour résoudre ce problème on a conçu un modèle utilisant conjointement l’écoulement de puissances optimales et l’optimisation des bénéfices lors de l’échange de l’énergie électrique. Le modèle développé est testé sur des réseaux standards IEEE.

Rotating electrical machines play an important role in the industrial world. Among them, the three- phase squirrel cage asynchronous machines are frequently used because of their robustness, their relatively simple construction and their low cost. Nevertheless, during their lifespan, these machines are submitted to external and internal stresses which can lead to several failures. In this paper, we present the estimate of the parameters sensitive to the defects, namely the rotor currents and resistances of the rotor bars, by using the Extended Kalman filter.

In the information science and technology such as computer science, telecommunications, processing of the signals or images transmission, the field effect components plays a major role. We are interested in this study in Schottky gate gallium arsenide field-effect transistors commonly called GaAs MESFET. In this paper, we mainly present the results of calculating the influence of gate length on input and output impedances of GaAs MESFET Transistors, this physical model is based on the analysis of two-dimensional Poisson equation in the active region under the gate. The theoretical results, based on analytical expressions that we have established, are discussed and compared with those of the simulation. 

In this paper, we present the application of the control of doubly fed induction machine, using direct torque control (DTC). This method has a simple and robust control structure; the performance of DTC strongly depends on the quality of the estimated actual stator flux and torque. DTC with switching tables provide excellent torque dynamics. The implementation of the DTC applied to a double feed induction motor is validated with simulated results. The results demonstrate that the proposed controller leads to performance improvements despite its simple structure.