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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
361

Implementation and Test of a 2D-integral-equation MoM-algorithm for the Analysis of Power-Bus Structures on Printed Circuit Boards / Implementation and Test of a 2D-integral-equation MoM-algorithm for the Analysis of Power-Bus Structures on Printed Circuit Boards

Štumpf, Martin January 2008 (has links)
Tato práce se zabývá analýzou power-bus struktur využitím metody založené na formulaci problému 2D hraniční integrální rovnicí ve frekvenční oblasti. Uvedená metoda byla implementována v Matlabu. Program umožňuje analyzovat obecné polygonální power-bus struktury s možností nastavení parametrů substrátu a libovolného počtu a umístění budících portů. Výstupem programu je frekvenční závislost rozložení elektrického pole mezi deskami struktury, vztahy mezi porty struktury vyjádřené např. impedanční maticí a vyzařovací diagram. Dále byla implementována možnost převodu výsledné impedanční matice do tzv. Touchstone formátu, pomocí něhož je možné modelovat analyzované struktury jako obecné N-porty (např. v ANSOFT Designeru), což umožňuje analýzu power-bus struktur s dalšími obvodovými prvky. Výsledky byly ověřeny pomocí existujících analytických vztahů pro jednoduché obdélníkové struktury, využitím komerčního simulačního programu a praktickým experimentem.
362

Vliv vodivých vzorků na vznik deformací vf magnetického pole / Impact of conductive material on RF magnetic field deformation

Vondra, Petr January 2009 (has links)
The work analyses formation of deformations of RF magnetic field within the environment of electrically and magnetically conductive materials. An analytic solution of the problem is created and the problems of numerical modeling are solved. In theoretical way, the work also familiarize with the use of magnetic resonance imaging method - the spin echo method (SE), with its features and possibilities of its use within the aim of the project. This method is used for experimental measurements of electrically conductive materials in the NMR laboratory in ISI AV Czech Republic. Results of the simulation are compared with results of the experimental measurement.
363

Magnetická pole pro biomedicínské experimenty / Magnetic fields for biomedical experiments

Otýpka, Jan January 2010 (has links)
In this work deals with magnetic fields for use in biomedicine. This solution involves the choice of the correct geometric arrangement of coils for generating magnetic field with a homogeneous distribution of magnetic induction of the widest possible area. The paper compares thre traditional types of coils, solenoid, toroid and Helmholtz coil. For Helmholtz and solenoid coil and is then carried out an analysis of the magnetic flux density in the inner space. Next part is devoted to electrical resonance in the LC circuit. This is then utilized for the development of pulsed magnetic field in the Helmholtz coil. It summarizes the theoretical and practical knowledge to design and construction of resonant converters. The end is devoted to the measurement of circuit parameters and verification of theoretical knowledge.
364

Studium vlivu magnetických polí na biologické tkáně / Study of the influence of magnetic fields on biological tissue

Vlachová Hutová, Eliška January 2012 (has links)
The aim of this research is to explore the influence of magnetic field on early somatic embryos (ESEs) of spruce and pine. The magnetic field is gradual. This is important for the experiment, each cluster of ESE was exposed to magnetic field of different intensity. The resulting report of this experiment consists of the comparison between various methods of image analysis and the difference in growth of ESEs due to different exposure to magnetic field and surrounding temperature. Enclosed is a proposal of ESE size computing algorithm from a given image.
365

Řešení rozložení magnetického pole ve stejnosměrném stroji / Solution magnetic field distribution in DC machine

Hájek, Jan January 2012 (has links)
This thesis deals with distribution of magnetic fields in the DC machine. Part of this thesis is the introduction of DC machines, principles of operation and distribution of DC machines. There is also discussed electrically commutated motors. The thesis demonstrates the types of permanent magnets and their properties. Then there is an analysis of the magnetic field electrically commutated motor Atas Nachod in the Ansoft Maxwell. Using Ansoft Simplorer, switching is carried out of the engine. Another part of this work is the analysisthe magnetic field electrically commutated motor Atas Nachod for three types of slot of the stator of the engine. Here it is seen what impact the change has slot on the distribution of magnetic field in the EC motor. Finally, training is carried out measurements of electrically commutated motor BOYANG BY92BL48-4000-2200.
366

Návrh vysokootáčkového asynchronního motoru / Design of high-speed induction motor

Svoreň, Jan January 2012 (has links)
This work deal with troubleshooting of problem parts of high-speed induction machines. Introduction is about conception of induction machines with reference to construction specialities due to high rpm and because machines are fed by inverter. Next part is focused to design problems. A classical induction machine was measured to determination change of various losses in classic and high-speed induction machines. The computation of laboratory sample high-speed motor was specified for calculation of effective resistance and leakage reactance of solid-steel rotor with copper layer. The results of numerical calculation were validated by using finite elements method and machine design was adjusted for improving operation characteristic.
367

Analýza vysokootáčkového asynchronního motoru / Analysis of high-speed induction motor

Klíma, Jiří January 2014 (has links)
This thesis deals with the problem of the high-speed induction machines. In the introduction the design of the machines and problem areas are discussed. The feeding from the frequency converter and the mechanical strength of the rotor appear to be the biggest problem. High-speed engines with solid rotors were designed. The first model is equipped with a conductive cooper layer on the surface. This model is exposed to harmonic and non-harmonic input voltage and then the results of the simulations are compared. The following model of the thesis is equipped with axial slots. In the practical part of the thesis no load measurement is taken. One point was measured at nominal frequency. At the end of the thesis the results of the measurements are compared with the results of the figures extracted from Maxwell software.
368

Výpočet stejnosměrného elektromagnetu a jeho experimentální ověření / Calculation of DC electromagnet and its experimental verification

Steidl, Adam January 2015 (has links)
Content of this thesis deals with electromagnets as operating elements in electric machines. Thesis is divided in two main parts, theoretical and practical. The theoretical part describes electromagnets as electric machine , usage of electromagnets in electrical devices as operating element. Electromagnets are further divided in groups on basis of different criteria. Next, the theory of electromagnetic fields and methods of assesment of static pull and dynamic characteristics is described. Construction and function analysis of researched electromagnet with permanent magnets, which serves as trigger in compact circuit breaker, is also included in this part. Practical part includes measurement of force quantities of researched electromagnet in different operating states an its evaluation. For analysis of dynamic quantities with finite element method were created two-dimensional and three-dimensional models. Evaluation of analysis follows. After that is described simplified design of electromagnet, based onoperating states of researched electromagnet. This part is closed with comparation between results of analysis and designed values of electromagnets.
369

Návrh a analýza synchronních strojů s permanentními magnety / Design and analysis of permanent magnet synchronous machines

Blaha, Jan January 2015 (has links)
Characteristics of synchronous machines with permanent magnets depend among others on geometric layout of the machine section. Unlike EC motors, where rectangular arrangement of quantities is suitable, these machines require sinusoidal behaviour. Specific forming of individual machine parts is partially derived from this requirement. This thesis deals with design of such machines, including various geometrical modifications of their sections and examination of influence of those modifications. The thesis includes also analytical calculation procedure of machine parameters as well as verification of final characteristics using the finite element method. It results in a combination of various design methods. FEMM, Maxwell RMxprt and Maxwell 2D Transient Analysis programs were used for verification. Individual modifications of machine geometries are applied to machines with concentrated windings with different ratio of number of slots and poles, and differences between machines and results of individual methods are compared.
370

Výpočet stejnosměrného elektromagnetu a jeho experimentální ověření / Calculation of DC electromagnet and its experimental verification

Steidl, Adam January 2015 (has links)
Content of this thesis deals with electromagnets as operating elements in electric machines. Thesis is divided in two main parts, theoretical and practical. The theoretical part describes electromagnets as an electric machine, usage of electromagnets in electrical devices as operating element. Electromagnets are further divided in groups on the basis of different criteria. Next, the theory of electromagnetic fields and methods of assesment of static pull and dynamic characteristics are described. Construction and function analysis of researched type of electromagnet from OEZ company with permanent magnets, which serves as trigger in compact circuit breaker, is also included in this part. Practical part includes measurement of force quantities of an electromagnet in different operating states and its evaluation. For analysis of dynamic quantities with finite element method was created suitable three-dimensional model of electromgnet. Model is used for simulation ofdifferent operating states.The last part describes measurement of dynamic characteristics of the electromganetic system. This part is closed with comparation of results.

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