This thesis deals with the steady-state, dynamic and control aspects of new type of brushless configuration of a doubly-fed induction machine in which the slip rings and carbon brushes are replaced by rotating power electronics and a rotating exciter. The aim is to study the stability of this novel configuration of the generator under mechanical and grid disturbances for wind power applications. The derivation, development and analysis of the steady-state model of the brushless doubly-fed induction machine with a rotating excitor and the power electronic converters mounted on the shaft and rotating with it, is studied. The study is performed at rated power of the generator between ±20% slip range. Moreover unity power factor operation between ±20% speed range is also discussed. Furthermore dynamic modeling and control aspects of the generator are also analyzed. The controllers were designed using Internal Model Control principles and vector control methods were used in order to control the generator in a closed-loop system. It is shown that through the use of proper feedback control, the generator behaves in a stable state both at super-synchronous and sub-synchronous speeds. Moreover Low Voltage Ride Through of the generator during symmetrical and unsymmetrical voltage dips is also investigated. Passive Resistive Network strategy is employed for Low Voltage Ride Through of the generator during symmetrical voltage dips. On the other hand, Extended Vector Control is used in order to control the negative sequence currents during unsymmetrical voltage dips. Suppression of negative sequence currents is important as they cause extra heating in the windings and affects the lifetime of the mechanical and electrical components of the generator and system due to oscillations in power and torque. In addition to the above studies a steady-state model of a single-fed induction machine is also developed and investigated where the rotating exciter is removed and the rotor windings are short-circuited through the two rotating power electronic converters. In this way the slip power circulates in the rotor and with the help of the two rotating electronic converters, rotor current is used to magnetize the induction machine thereby improving the power factor. The steady state model is verified through experimental results. / <p>20120914</p> / Brushless Wind Generator with Rotating Power Electronic Converters

L’utilisation des semi-conducteurs à large bande interdite (wide bandgap ou WBG) tels que le carbure de silicium SiC, le nitrure de gallium GaN, le diamant, etc… s’est répandue dans le domaine de l’électronique de puissance ces dernières décennies. Leurs caractéristiques électroniques et mécaniques font des WBGs des solutions alternatives pour remplacer le traditionnel silicium. Cependant, des études supplémentaires sont indispensables pour améliorer la tenue en tension, les pertes statiques et dynamiques et les performances en fonctionnement à haute température des composants WBGs. Dans ce cadre, deux bancs expérimentaux OBIC (Optical Beam Induced Current) spécifiques « en cours de développement » sont mis en place pendant cette thèse. L’OBIC consiste à éclairer avec un faisceau laser de longueur d’onde appropriée une jonction polarisée en inverse, des porteurs de charge sont alors créés par absorption photonique. On peut alors mesurer un courant induit par faisceau optique (OBIC) lorsque les porteurs sont générés dans la zone de charge d’espace. Après une première phase de préparation et d’adaptation de l’environnement expérimental, des essais ont mené à la démonstration du principe de génération multi-photonique en éclairant une jonction SiC avec un faisceau vert (532 nm). L’analyse des différentes mesures OBIC nous a permis de construire une image du champ électrique à la surface de la diode : une analyse non destructive pour étudier l’efficacité des protections périphériques des jonctions et pour détecter les défauts dans la structure cristalline. Egalement, la durée de vie des porteurs minoritaires a été déduite par l’analyse de la décroissance du courant OBIC au bord de la jonction. Les coefficients d’ionisation sont également déterminés par la méthode OBIC, ces coefficients sont des paramètres clés pour la prévision de la tension de claquage des composants. Nous avons réalisé des mesures OBIC dans le GaN, et nous avons observé un effet d’absorption bi-photonique dans le diamant avec un faisceau UV (349 nm). / In the last few decades, the use of wide bandgap (WBG) semiconductors (silicon carbide SiC, gallium nitride GaN, diamond, etc…) has become popular in the domain of power electronics. Their electronic and mechanical characteristics made of the WBGs a good alternative to the traditional silicon. However, additional studies are mandatory to improve the breakdown voltage, static and dynamic losses, and the performance at high temperature of the WBG devices. In this context, two specific experimental benches OBIC (Optical Beam Induced Current) -under development- are set up during this thesis. OBIC method consists to generate free charge carriers in a reverse biased junction by illuminating the device with an appropriate wavelength. An OBIC signal is measured if the charge carriers are generated in the space charge region. After a first phase of preparation and adaptation of the experimental environment, OBIC measurements led to demonstrate the multi-photonic generation by illuminating a SiC junction with a green laser (532 nm). OBIC measurements allowed giving an image of the electric field at the surface of the diode: OBIC presents a non-destructive analysis to study the efficiency of the peripheral protection and to detect the defects in the semi-conductor. Minority carrier lifetime was also deduced by studying the OBIC decrease at the edge of the space charge region. Ionization rates were extracted using OBIC method; these coefficients are key parameters to predict the breakdown voltage of the devices. OBIC measurements were also realized on the GaN, and two-photon generation was highlighted by measuring an OBIC current in the diamond when illuminating it with a UV laser beam (349 nm).