This thesis is focused on design of piezoelectric energy harvester with additional nonlinear stiffness. Linear generator has very narrow resonance frequency bandwidth. It makes the resonance mechanism very sensitive to tuning up of the resonance frequency and it can be tuned only for one narrow vibration peak. The main idea for using of the vibration energy harvester with nonlinear stiffness is to make resonance frequency bandwidth wider, so the generator will be useable for more excitation frequencies. In this thesis is used generator Midé V21BL and additional nonlinear stiffness is realized with permanent magnets.

Mechanical ventilators are devices in critical care to assist breathing in case of expiratory dysfunction. The expiratory valve is a critical component to the ventilator as it controls the pressure in the patient’s lungs. The design process of a new expiratory valve assembly is a time consuming one due to the wide range of possible design solutions both the voice-coil actuators and membrane valves typically used in ventilators. This thesis evaluates the possibility of creating and using analytical models for model based development to speed up the early design phases of a expiratory valve assembly. The main components, voice-coil actuator and membrane valve are modelled separately and experimentally verified. A complete expiratory system model and hardware-in-the-loop test setup are constructed in order to explore how well can the dynamic properties and control performance of valve assembly be predicted. Finally various questions in the valve assembly design are explored and a new design is proposed to demonstrate the capabilities of the model based approach. The resulting voice-coil and membrane valve models can be considered accurate enough for fast exploration of the design space, as an error rate below 10% is reached without manual tuning for each design. / Mekaniska ventilatorer är en utrustning inom intensivvården för assisterad andning för patienter med nedsatt andningsförmåga. Utandningsventilen är en kritisk komponent till ventilatorn då den kontrollerar lungtrycket hos patienten. Design processen för en ny utandningsventil är en tidskrävande process mycket på grund av den mängd olika design möjligheter som kan utforskas för både talspole aktuatorn samt membran ventilen som oftast används i ventilatorerna. I detta examensarbete utforskades möjligheterna till att skapa och använda analytiska modeller för modellbaserad utveckling för att accelerera de tidiga design stadierna för en utandningsventil. Huvudkomponenterna, talspole aktuatorn och membran ventilen är modellerade separat och experimentellt verifierade. En fullständig modell för hela utandningssystemet samt en hardware-in-the-loop test plattform är konstruerad för att utforska hur väl de dynamiska egenskaperna samt kontroll prestandan för en utandningsventil kan prediceras. Slutligen utforskas diverse frågor angående ventil designen och en ny design föreslås för att demonstrera möjligheterna med en modellbaserad metod. Den slutliga modellen för både talspole aktuatorn och membran ventilen kan betraktas som tillräcklig precisa för snabb utforskning inom de olika design möjligheterna, då en felprocent under 10% är uppnådd utan manuell finjustering för varje design.

In this thesis, the basics of electromagnetic theory for wave-energy conversion are reviewed, some of the characteristics of the ocean wave are investigated, some of the power take-off (PTO) systems are introduced, and details about linear permanent magnetic machines, in particular, are discussed.  The thesis aims to model the novel linear transverse flux machine designed by Anders Hagnestål and to build hysteresis current controller for power factor correc- tion. Although this machine is expected to have high performance in terms of efficiency, it also exhibits a strong mutual interaction between the three phases of the machine. Thus, simplification of the actual model of the machine is im- posed to mitigate the complexity of the machine and facilitate the Simulink model. Four cases of the double band hysteresis control are studied. The cur- rents seem to be responding properly to the control scheme; however, software and hardware programming of a microprocessor would be preferable to ensurethe applicability of the control strategy in a real environment. / I detta examensarbete undersöks elektromagnetisk teori och havsvågors egenskaper. Några energiomvandlingssystem introduceras och permanentmagnetiserade maskiner diskuteras i detalj. Syftet med avhandlingen är att modelleraen ny linjär transversalflödesmaskin som är designad av Anders Hagnestål och att bygga en hysteresbaserad strömkontroll för denna. Även om maskinen förväntas prestera bra, uppvisar den också en stark ömsesidig magnetisk interaktion mellan de tre faserna. För att kunna hantera detta problem och därmed kunna genomföra simuleringar införs en förenklad elektromagnetisk modell av maskinen. En strömkontroller har implementerats i Simulink, där fyra fall av dubbelbandshystereskontroll studerats. Resultaten från simuleringarna visar att strömkontrollern fungerar. Nästa steg i projektet är att utföra mjukvaru och hårdvaruprogrammering av en mikrokontroller för att testa systemet i enverklig miljö.

Les travaux effectués lors de cette thèse portent sur l'optimisation de la configuration magnétique des propulseurs à effet Hall. Ceci regroupe deux objectifs: d'une part la réalisation d'un propulseur à effet Hall dont la topologie magnétique est entièrement paramétrable, ce qui constituera un outil précieux pour l'étude de l'impact du champ magnétique sur le fonctionnement du propulseur et d'autre part, l'étude de moyen de conception rationalisée de circuits magnétiques pour ces mêmes propulseurs. Le premier sujet a conduit à la réalisation du PPS-Flex, un propulseur proposant une structure de circuit magnétique innovante offrant un grand nombre de degrés de liberté en termes de réglage du champ magnétique produit. La deuxième thématique a quant à elle été abordée en s'appuyant sur des méthodes d'optimisation (paramétrique et topologique) permettant d'aboutir à un circuit magnétique optimal pour un ou plusieurs critères de conception (fidélité du champ magnétique généré, minimisation de la masse, du volume total, etc.) / The works made during this thesis concern the optimization of the magnetic configuration of propellers with effect Hall. This groups two objectives: on one hand the realization of a propeller with effect Hall the magnetic topology of which is completely customizable, which will establish a precious tool for the study of the impact of the magnetic field on the functioning of the propeller and on the other hand, the study of way of design rationalized of magnetic circuits for these same propellers. The first subject led to the realization of the PPS-Flex, a propeller proposing an innovative magnetic structure of circuit offering a large number of degrees of freedom in terms of regulation of the magnetic field produces. The second theme approached as for her resting on methods

In the introduction a traction circuit is analyzed with different types of electric devices. The thesis describes power railway electric circuits, their loads and types of used contactors. Railway standards chapter summarizes requirements of standards for railway contactors. Follows literature focusing on power current switching and power switching devices design. Based on previous, a design procedure is developed for railway MV contactor in accordance with end-user and standards requirements. Thesis closes with pre-designing a railway contactor by calculating electrodynamic forces, heatflow and mechanical components.

In this thesis is described the function and design of the transformer designed on ferromagnetic core, composed of transformer sheets. It is explained a transient inrush current of the transformer. In this work is inserted voltage and current waveforms, designed printed circuit board, serving to reduce the inrush current.

The aim of this master´s thesis is to introduce methods of diagnostics of vibrations in electrical machines. Describe the various vibration sources located inside and outside of the electric machine. Description of the sources of vibration is then preferably dedicated to vibration of electromagnetic origin. There is a description of the construction of an asynchronous motor and the magnetic circuit, the theory of vibrations and their origin. Described are also vibration sensor enables measurement and mathematical tools for their evaluation. In this work also practical vibration measurements on an asynchronous motor, data processing, their subsequent analysis and computer simulation of electromagnetic vibration origin. The conclusion of this work is devoted to the evaluation of the data obtained.

he recent development of the power electronic and high-energy permanent magnets enables developing synchronous machines excited by permanent magnets, that are able to meet very gradual and exact control demands. Due to high torque density, that permanent magnet machines reach, the synchronous motors may be used even in direct (gearless) drives. One of the branches, in which direct drives can be used, is material handling. The most propelling drives in this branch consist of induction motor, simple gearbox with invariable gear ratio mounted to the drive wheel. Main aim of this thesis is designing the direct drive motor for low-lift truck. Motor is built-in the driven wheel, therefore outer rotor design appears to be more suitable. Two types of motors – permanent magnet synchronous motor and transverse flux motor have been chosen on the basis of technical paper study, many years lasting experience and verification computations. Both motor types are described in great details in this thesis. Both synchronous motor with PM and transverse flux motor have been designed for direct drive of the given low-lift truck. The proposals of both motors have been optimized by means of finite element method. Based on these design optimizing computations, both motors have been designed, produced and design accuracy has been verified by laboratory testing. Synchronous motor with PM achieves better electromagnetic parameters and its production is also simpler, therefore this motor is more suitable for this application. The solution with transverse flux motor may save substantial amount of active materials. Results of the detailed optimization and comparison of both motor types are the main benefits of this thesis.

In this thesis is described the function and design of the transformer designed on ferromagnetic core, composed of transformer sheets. It is explained a transient inrush current of the transformer. In this work is inserted voltage and current waveforms, designed printed circuit board, serving to reduce the inrush current.

Lors de la réalimentation des auxiliaires d’une tranche nucléaire, l’étape la plus à risque est la remise sous tension brusque du transformateur à cause des surtensions. Dans un soucis perpétuel d’amélioration de la modélisation de ces transitoires, les modèles et techniques doivent évoluer. Le but de ces travaux de thèse est de proposer de nouvelles méthodologies permettant d’évaluer les paramètres mal connus de la modélisation. Lors des mises sous tension des lignes électriques, une méthodologie s’appuyant sur l’identification (optimisation ou techniques issues du traitement du signal) permet de déterminer les paramètres variables de la modélisation. Cependant, un des paramètres influents pour les surtensions est le flux rémanent. Face aux problèmes actuels rencontrés pour l’estimer (méthode non directe, dérive, …), une nouvelle méthode basée sur la mesure des flux de fuites du circuit magnétique est proposée. Des mesures réelles utilisant des capteurs de technologie « fluxgate » sont réalisées et permettent d’estimer le flux rémanent. / During the re-energization of the auxiliaries of a nuclear power plant, the more dangerous step is the re-energization of the power transformer, because of the temporary overvoltages. In order to improve the transient modeling, models and techniques may be improved. The purpose of this thesis is to suggest new methodologies to identify the uncertain parameters of the model. When the line re-energization occurs, an identification methodology (optimization or methods using signal processing) allows determining the model variable parameters. However, one of the most important parameters in the overvoltages is the residual flux. Given the actual problems found on estimation strategies (no direct method, derivation,…), a new method established for the leakage flux measurement of the magnetic circuit is proposed. Real measurements using « fluxgate » technology sensors were realized, permitting to estimate the residual flux.