Suite à la stratégie d’électrification poursuivie dans le domaine des véhicules terrestres, l’industrie aéronautique s’oriente également vers l’introduction de la propulsion électrique. L’hybridation est le premier pas vers un aéronef plus électrique. L’objectif principal de cette thèse est de développer un outil informatique permettant de pré-dimensionner des machines électriques conventionnelles de différentes typologies susceptibles d’être utilisées dans le cadre du projet d’hybridation et de modéliser les comportements magnétique et thermique de ces machines.Après une étude bibliographique sur le pré-dimensionnement et la modélisation électromagnétique et thermique des machines électriques conventionnelles, des modèles (semi-)analytiques basés sur les méthodes des circuits équivalents magnétique et thermique ont été établis. La validation des modèles proposés a été menée en comparant les résultats obtenus avec des données issues de la littérature, des résultats issus de simulations numériques par éléments finis ou à des mesures expérimentales réalisées sur des machines prototypes. Une attention toute particulière a été portée au couplage des analyses magnétique et thermique. Des études de sensibilité ont permis de déterminée les limites d’utilisation de l’outil développé. / Inspired by the strategy of electrification pioneered in the automobile industry, the aeronautics sector tends as well towards the implement of the electrical propulsion. The hybridisation is the first step in the direction of a completely electrical aircraft. The main goal of this thesis is to develop a computer-based tool permitting to pre-design and model electromagnetic and thermal behaviour of the conventional electrical machines of different typologies suitable for use in the scope of hybridisation project.Basing on a general state of art on the pre-design and electromagnetic and thermal models of the conventional electrical machines, the (semi-)analytical models reposed on magnetic and thermal equivalent circuit methods have been developed. The proposed models have been validated by comparing the obtained results with the results from the literature, the results of numerical analysis or with the results of experimental tests carried out on different machine-prototypes. Special attention has been paid to the coupling of magnetic and thermal analysis. Different sensibility studies permitted to define the application limits of the developed tool.

Policies to reduce emissions from transportation are implemented by different World and European<p>associations. Personal and freight transportation is one of the key contributors in GHG<p>emissions, being the second biggest GHG emitter after energy sector in the European Union.<p>The policies to reduce emissions from transportation are focusing on the optimization of the efficiency<p>of the existing vehicles, the development of new sustainable fuels and propulsion systems<p>and the electrification of the vehicles<p>The continuously increasing price of the permanent magnets and the shortage of rare earths<p>demand the finding of alternatives for the permanent magnet synchronous machines which is<p>currently the leading technology in several domains as hybrid and full electric propulsion and<p>wind turbines due to their best overall performances.<p>The good efficiency and the large constant power-speed ratio in addition to low the cost, high<p>reliability and fault-tolerance make the SRM a candidate with real chances on the market of<p>vehicle propulsion. The main drawbacks of the SRM related to the torque ripple, noise and<p>vibration make the research object in R&Ds all over the world.<p>This thesis is focused on the development of an efficient and robust switched reluctance drive<p>which can be integrated in a hybrid dive train or can be solely used for electric vehicle traction.<p>To achieve this goal, various instantaneous and average torque control techniques are implemented<p>and compared. A converter is designed, built and integrated on a test bench which<p>allows testing SRMs for vehicle propulsion. An investigation on noise production in SRDs ends<p>the thesis. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Le domaine de la physique des plasmas froids a émergé avec les premières découvertes fondamentales en physique atomique et en physique des plasmas il y a plus d’un siècle. Toutefois, ce domaine a été rapidement orienté vers les applications. L’une des plus importantes dans la première moitié du XXème est le "Calutron" (California University Cyclotron), inventé par E. Lawrence à Berkeley, qui faisait partie du projet Manhattan, et utilisé comme un spectromètre de masse pour séparer les isotopes de l’uranium. Dans un rapport du projet Manhattan daté de 1949, D. Bohm fait deux observations qui sont fondamentales pour la physique des plasmas froids :(i) Les ions doivent avoir une énergie cinétique minimales lorsqu’ils entrent dans la gaine du plasma, estimée à Te/2, Te étant la température électronique.(ii) Le transport du plasma à travers un champ magnétique est augmenté par des instabilités.La propulsion électrique par plasma est utilisée pour des satellites militaires et des sondes spatiales depuis les années 1960 et a suscité un intérêt grandissant ces vingt dernières années avec le développement des applications commerciales des technologies spatiales. Néanmoins, les mêmes questions que celles auxquelles D. Bohm était confronté, c’est-à-dire le transport multidimensionnel, l’interaction plasma-gaine, et les instabilités, se posent toujours. La théorie et les simulations sont d’autant plus importantes pour la conception des systèmes de propulsion électrique que les tests en conditions réelles nécessitent le lancement d’un satellite dans l’espace.Dans ce travail, nous établissons les équations du transport multidimensionnel dans un plasma isotherme, nous proposons un critère de gaine qui permet de rendre compte de la saturation du champ magnétique dans un plasma froid et faiblement ionisé, et nous modélisons le refroidissement des électrons à travers le filtre magnétique du propulseur PEGASES (Plasma Propulsion with Electronegative Gases). Toutes les théories sont motivées et validées par un grand nombre de simulations particulaires PIC bi-dimensionnelles, en utilisant le code LPPic qui a été partiellement développé dans le cadre du projet. Enfin, les cas de simulation sont étendus à une décharge inductive à plasma dans l’iode, avec un nouvel ensemble de section efficaces de réaction. / The field of low temperature plasma physics has emerged from the first fundamental discoveries in atom and plasma physics more than a century ago. However, it has soon become very much driven by applications. One of the most important of them in the first half of the XXth century is the "Calutron" (California University Cyclotron) invented by E.~Lawrence in Berkeley, that was part of the Manhattan project, and operated as a mass spectrometer to separate uranium isotopes. In a 1949 report of the Manhattan project, D.~Bohm makes two observations that are fundamental for low-temperature plasma physics.(i) The ions must have minimum kinetic energy when they enter the plasma sheath estimated to T_e/2 , Te being the electron temperature in eV ;(ii) Plasma transport across a magnetic field is enhanced by instabilities.Plasma electric propulsion is used on military satellites and space probes since the 1960s and has gained more and more interest for the last twenty years as space commercial applications were developing. However, the same questions as the ones D.~Bohm was faced with, namely multi-dimensional transport, plasma sheath interaction, and instabilities, arise. Theory and simulation are even more important for electric space propulsion systems design since testing in real conditions involves to launch a satellite into space.In this work, we derive the equations of the multi-dimensional isothermal plasma transport, we establish a sheath criterion that causes the magnetic confinement to saturate in low-temperature, weakly ionized plasmas, and we model the electron cooling through the magnetic filter of the PEGASES (Plasma Propulsion with Electronegative Gases) thruster. All the theories are driven and validated with extensive two-dimensional particle-in-cell (PIC) simulations, using the LPPic code that was partially developed in the frame of this project. Finally, the simulation cases are extended to an iodine inductively coupled plasma (ICP) discharge with a new set of reaction cross sections.

This master's thesis is focused on conceptual design of glider with electric propulsion system following the CS-22 regulation. Statistical analysis of the glider with an auxiliary electric engine has been carried out in order to determine basic design parameters for conceptual design. Based on analytical drag polar, the flight performance parameters are calculated, in particular flight range and influence of the solar panels on the flight range. This thesis also includes preliminary design solution of accumulator placement within the wing.

This Master of Science thesis was written based on the shipbuilder Kockums AB feasibility study regarding the development of an All- Electric Ship for the Swedish Navy. The thesis was aiming at addressing voltage stability issues in a dc system fed by PWM rectifiers operating in parallel when supplying constant power loads. A basic computer model was developed for investigating the influence from various parameters on the system. It was shown that the voltage stability is dependent upon the ability to store energy in large capacitors. It was also shown that a voltage droop must be implemented maintaining load sharing within acceptable limits. Different cases of operation were modelled, faults were discussed, and the principal behaviour of the system during a short-circuit was investigated. It was shown that the short-circuit current is much more limited in this type of system in comparison to an ac system. It was concluded that more research and development regarding the components of the system must be performed.

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Hall-effect thrusters (HETs) are among the most commonly used propulsion systems for attitude and orbit control of satellites. As an arrangement in a cluster or individually, equipped with a mechanical suspension, thrust in all three spatial directions can be generated, but requires additional mechanisms and components. Therefore, the Technische Universität Dresden (TU Dresden) is currently working on a concept for developing a Hall-effect thruster with integrated thrust vector control, which would allow steering in all three spatial directions with just a single thruster. This new concept is intended to work solely by influencing the ion beam and should not have any additional mechanical components. The HET will come with a segmented anode to set different electrical potentials at the anode and cause an inhomogeneous distribution of the electric field within the discharge channel, which results in an inhomogeneous force vector distribution at the exit plane. It is assumed that this will generate turning moments around the center of gravity. Deliberately causing those turning moments can therefore be used for steering with just one thruster. This work presents the concept of the propulsion system, gives an outlook on the advantages of its technology and shows capabilities for space applications.

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