Modern power systems require multiple conversions between DC and AC to deliver power from renewable energy sources. Recent growth in DC loads result in increased system costs and reduced efficiency, due to redundant conversions. Advances in DC microgrid systems demonstrate superior performance by reducing conversion stages. The literature reveals practical DC microgrid systems composed of wind and solar power to replace existing fossil fuel technologies for residential consumers. Although higher efficiencies are achieved, some household appliances require AC power; thus, the need for highly efficient DC to AC converters is imperative in establishing DC microgrid systems. Resonant inverter topologies exhibit zero current switching (ZCS); hence, eliminate switching losses leading to higher efficiencies in comparison to hard switched topologies. Resonant inverters suffer severe limitations mainly attributed to a load dependent resonant frequency. Recent advancements in power electronics propose an electronically tunable inductor suited for low frequency applications [24], [25]; as a consequence, frequency stability in resonant inverters is achievable within a limited load range. This thesis characterizes the operational characteristics of a low-frequency series loaded resonant inverter using a manually tunable inductor to achieve frequency stability and determine feasibility of utilization. Simulation and hardware results demonstrate elimination of switching losses via ZCS; however, significant losses are observed in the resonant inductor which compromises overall system efficiency. Additionally, harmonic distortion severely impacts output power quality and limits practical applications.

The aim of this diploma thesis is to study the resonant converters operation. This paper is concretely specialized to design and implementation the LLC resonant converter with output power about 350 watts. LLC resonant converter is prospective solution for similar applications. The general advantages are that the power MOSFETs are working on zero voltage switching condition, which reduce the switching loss and improve EMI performance. The detailed design for the LLC resonant tank characteristics presented in this paper, which fully guarantees the ZVS condition. This study is based on replacing the rectifier and load by an equivalent resistance applies the first harmonics approximation and the assumption that the current trough the diodes of the output rectifier has a sinusoidal waveform.

This article describes some methods of measuring complex permitivity in milimeter – wave band, their characteristics, anvatages and disadvantages. Discused are here the reasons for their use in the construction of work place. On the basis these reasons is chosen the best method for practical measurement. That is cavity resonant method. Article contain description of designed measurement system. Whitch is verified by computer simulating of developed model in HFSS Ansoft. Text contain also result of simulations and execute computing of comlex permittivity and tangent loss. In Conclusion is desribed results of practical permittivity measure with realized measurement system.

This thesis deals with designing of an induction heating of small iron parts. This device should be primarily designed for a farrier practice or an artistic blacksmithing. Considering the practice, the referential heated iron part will be a horseshoe. The basis of this device is a power inverter with serial resonant circuit connected to inverter as a load. This thesis contains designing and development of electrical and mechanical parts of whole device. It means control circuits, resonant circuit, box for heated part, etc. At the end of this thesis is realization of the device, electrifying, optimization and testing. During the test the horseshoe was heated close to demanded temperature.

Les équipementiers automobiles d’organes à hautes exigences sécuritaires travaillent sans cesse sur l’amélioration de la sûreté de fonctionnement de leurs systèmes et préparent leur insertion dans l’air du véhicule autonome. Dans ce cadre, nous avons travaillé sur la conception et le développement d’un capteur de force pour la direction à assistance électrique (DAE) avec le défi de proposer une solution sans fil, facile à fabriquer et à intégrer au système. Dans cette thèse, des travaux de modélisation et d’expérimentation ont porté principalement sur deux aspects : le capteur de force et son alimentation sans fil. Pour la mesure de force, une solution basée sur l'utilisation d'un matériau piézoélectrique a été proposée. L’utilisation d’un tel matériau pour la mesure de la composante dynamique de la force est largement répandu, cependant la mesure statique reste extrêmement réduite aux applications MEMS (mesure de pression). La technique repose sur l’onde acoustique de volume (Bulk Acoustic Wave). Un échantillon piézoélectrique inséré dans une structure, soumis à une force voit sa fréquence de résonance varier. Des travaux de modélisation analytique, éléments finis et multi-échelle ainsi que de l’expérimentation ont permis de comprendre les phénomènes physiques mis en jeux dans ce type de transducteur et de proposer des orientations pour la conception du transducteur de force optimal. Un démonstrateur a été mis en place permettant la mesure d’une force statique maximale de 1500 N. L'alimentation sans fil du capteur est assurée par la technique du couplage magnétique résonant. Vu le caractère conducteur et ferromagnétique de l’environnement du système de direction, une approche de modélisation basée sur la méthode des éléments finis et la méthode des constantes localisées a été mise en place afin d’étudier le comportement d’une telle technique dans cet environnement. Par la suite, une conception a été proposée et un prototype a été réalisé. Des mesures expérimentales ont montré que la conception répond au cahier des charges imposé par l’entreprise. / Original equipment manufacturer for automotive components with high safety requirements are continually working to improve the system safety and prepare their integration to the driverless car. Within this context, we worked on the design and development of a force sensor for the electric power steering (EPS) system with the challenge of providing a wireless solution, easy to manufacture and to integrate to the system. In this thesis, modeling and experimental activities have focused mainly on two aspects: the force sensor and its wireless power supply system. For force measurement, a solution based on piezoelectric material was proposed. The use of such material to measure the dynamic component of the force is widespread; however, static force measurement remains extremely limited to MEMS applications (pressure measurement). The technic utilizes the bulk acoustic wave (BAW). The resonance frequency of a piezoelectric specimen positioned within a mechanical structure varies with an externally applied force. Analytic modeling activities, finite element method based and multi-scale approach with experimentation activities allow the understanding of the physical mechanisms behind the observed behavior of the transducer and to propose guidance for optimal design of the force transducer. A demonstrator was set up and showed a static force measurement capability up to 1500N.The wireless power supply is achieved by the resonant magnetic coupling technique. In order to analyze the effect of the environment of the electric power steering system characterized by conductive and ferromagnetic parts, a modeling approach based on the finite element method and the lumped-element method was adopted. Afterwards, a design was proposed and a prototype was carried out. The experimental measurement shows that the design meets the company requirements.

<p>Pasivni bežični LC senzori projektovani su u tehnologiji štampanih kola (PCB) i u tehnologiji nisko-temperaturno pečene keramike (LTCC). Predstavljena su tri tipa LC senzora izrađenih na PCB-u u jednoslojnoj i dvoslojnoj štampi. Takođe su prikazana i dva tipa LC senzora izrađenih u LTCC tehnologiji. Karakterizacija senzora je izvršena u laboratorijskim uslovima a za testiranje korišćeni su građevinska opeka i siporeks blok kao jedni od najčešće korišćenih materijala u građevinskoj industriji za zidane objekte.</p> / <p>Passive LC wireless sensors are designed in technology printed circuit boards (PCB) and the technology of Low Temperature Co-Fired Ceramics (LTCC). Presented are three types of LC sensors made on the PCB in the monolayer and bilayer press. It also presents two types of LC sensors manufactured in LTCC technology. Characterization of the sensor is carried out in the laboratory for testing were used building bricks and aerated concrete block as one of the most commonly used materials in the construction industry.</p>

The non-resonant bounded uniserial representations of Vec(R) form a certain class of extensions composed of tensor density modules, all of whose subquotients are indecomposable. The problem of classifying the extensions with a given composition series is reduced via cohomological methods to computing the solution of a certain system of polynomial equations in several variables derived from the cup equations for the extension. Using this method, we classify all non-resonant bounded uniserial extensions of Vec(R) up to length 6. Beyond this length, all such extensions appear to arise as subquotients of extensions of arbitrary length, many of which are explained by the psuedodifferential operator modules. Others are explained by a wedge construction and by the pseudodifferential operator cocycle discovered by Khesin and Kravchenko.

(Hamiltonian chaos and its application to anomalous dynamics in turbulent environment) RMP-induced ELM control has been tested on several tokamaks. It is believed that increase of electron transport across the magnetic field plays an important role. Edge plasma turbulence also affects dynamics in the edge region of tokamak. We study the simultaneous effect of plasma turbulence and RMP-induced stochastic magnetic field within the single-particle framework. We find out that the plasma turbulence is an important element of dynamics that should be taken into account in further (especially single-particle) studies.

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographies. / by Mostafa Ameen Foda. / Sc.D.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第17771号 / 理博第3894号 / 新制||理||1562(附属図書館) / 30578 / 京都大学大学院理学研究科化学専攻 / (主査)教授 谷村 吉隆, 准教授 安藤 耕司, 教授 寺嶋 正秀 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM