Infoscience

Thesis

Transmission électromagnétique rotative d'énergie et d'information sans contact

The transmission of energy or signals to a rotating device is generally carried out by systems with sliding contacts. This technology, apparently simple, generates serious nuisance such as abrasion of the elements in contact, electric noises and requires a relatively important volume. These devices, of limited life cycle, generally request quite expensive maintenance. The transmission of energy or information by induction seems then an interesting alternative to this technology. In fact, the constant evolution of electronic components and ferromagnetic materials developed for high frequency power applications opens the way to reliable, integrated and economical system supplied by induction. This thesis can be a useful reference document to make a choice and to design an energy and/or information transmission device by induction, based on the principle of the transformer. Various solutions with or without carried ferrite structures are proposed, also for different geometries including all invariance of the system parameters in relation to the rotation speed and the angular position. The first part of this work presents some high frequency converters integrating a transformer (Flyback, Forward…). This approach shows their possibilities as well as some of the corresponding elements of design. This part demonstrates also the interest of using sinusoidal signals to limit the disturbances caused by the power transmission system. Several calculation models of inductances, of the heating, of the iron losses and of the transformer (equivalent electric model) have been developed. Then different rotating transformers, the most adapted to this kind of transmission, have been designed. After validation and implementation of these models into a design software, several examples have been achieved and also integrated into a real system. The second part of this study is devoted to the transmission of information by induction. From the start, the transformer appears as a band pass type hence, penalizing the transmission modes using low and null frequencies. The transmission modes of certain communication systems are compatible with the characteristics of the transformer and then the information transformer is inserted directly within the data communication channel, without any other electronic components. In the contrary case, the modulation intervenes like an alternative to the transmission in baseband and proves to be an adapted solution when the transmission of power generates disturbances in the data communication channel of information (coupling between the two systems). In this case the modulation allows to separate the two respective spectra (disturbances and information) so that a filter device eliminates the disturbances without deteriorating the signal carrying information. Various approaches to transmit information were approached and are presented in this work. Design methods are also proposed. Besides, various developments show at the same time the feasibility and the obvious interest of these principles.

    Thèse École polytechnique fédérale de Lausanne EPFL, n° 2111 (2000)
    Faculté des sciences et techniques de l'ingénieur
    Laboratoire d'actionneurs intégrés
    Jury: Jean Bigeon, Jean-Dominique Decotignie, Freddy Gardiol, Pierre-André Mauesli

    Public defense: 2000-2-11

    Reference

    Record created on 2005-03-16, modified on 2016-08-08

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