http://depot.umc.edu.dz/handle/123456789/6095 2026-06-01T15:14:47Z http://depot.umc.edu.dz/handle/123456789/11130 Substitution des groupes tournants par des convertisseurs statiques. Kemouche, Abderrahmane; Grassivitch, Vladimir 126 f. 1989-10-01T00:00:00Z http://depot.umc.edu.dz/handle/123456789/6136 Classification automatique des défauts des moteurs asynchrones Bouguerne, Abla; Lebaroud, Abdesselam The diagnosis of bearings defects in electric machines has become an important area of research in recent years. Most studies on the detection of bearing faults using vibration measurements descended from sensors placed close to the mechanical elements to be monitored. For this reason, the work of this thesis focused on the automatic classification of bearing defects of the asynchronous machine with squirrel cage. We proposed a clustering approach to bearing defects. This approach is based on five steps: The first step uses the decomposition of the empirical method to separate each vibration signal in the different intrinsic mode functions, where each mode is in a specific frequency band. The second step extracts amplitudes and instantaneous frequencies for each mode in order to identify its frequency band by calculating the Hilbert marginal spectrum. The third step, the feature extraction phase is carried out by using the energy operator Teager-Kaiser (TKEO) .In the fourth step, vectors forms extracted was optimized from optimization by particle swarm which is a stochastic optimization method developed, based on the reproduction of social behavior. Finally, the final step relates to the automatic classification of optimized vectors that can be achieved through the Gaussian mixture model algorithm. This will make the relevance of attributes and automatically selection and classification of bearings defects in asynchronous electric machines. 2017-02-02T00:00:00Z http://depot.umc.edu.dz/handle/123456789/6135 Commande d'un convertisseur électromécanique; Application à un système Eolien Kerdoun Djallel; Saadi Fatima We present in this work the study of the energy transformation produced by wind generators us before fact the modeling of electromechanical drive multi-mass, composed of an electric machine and a mechanical load inter-connected by a bowden shaft. 88 f. 2013-01-01T00:00:00Z http://depot.umc.edu.dz/handle/123456789/6134 L'optimisation de la puissance réactive et le controle de tension à travers l'incorporation des dispositifs FACTS. Sekhane, Hocine; Labed, Djamel This memory proposes an appropriate solution for the optimization of reactive power, and voltage control through the incorporation of the flexible alternating current transmission systems “FACTS”. For this objective we proposed two shunt family devices the STATCOM and the SVC of (3TSC+1TCR) type. We presented by details their structure and operating principle, we also developed their mathematical models in the synchronous reference (d-q), and shown the relations between the various variables of the network according to the control parameters of these two compensators. For the STATCOM we chose the MLI command, and a command system for the SVC (3TSC+1TCR) comprises 04 units (measurement system, PI regulator of voltage, distribution unit and the switching unit). We chose the method (Watt-Var uncoupled) for the identification of the STATCOM references, and we applied the PI regulator for the command of two devices. The results of simulation with MATLAB/SIMULINK validated the models used and they indeed showed that these two compensators carried out with a great effectiveness our crucial objective in the optimization of reactive power and the voltage compensation in the test network studied. At the end we made a short comparison on technical and economical plans between these two FACTS compensators. 119 f. 2013-01-01T00:00:00Z