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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.
21

Spínané zdroje velkých výkonů - paralelní řazení zdrojů / High power switch-mode supplies - parallel connection

Kadlec, Josef January 2016 (has links)
This doctoral thesis deals with the issue of high power switched-mode power supplies that are designed as modular systems. The thesis describes series, parallel and series-parallel possibility of connected converters. System can achieve extremely high output current for converters connected in parallel. For converters connected in series, the system can achieve extremely high output voltage. The main goal of this thesis is to develop so-called reconfigurable modular system. It is a system that can change converters connection of serial, parallel or series-parallel connection - during its operation. This option to change converters connection significantly extends the control range of output voltage and output current of the whole system. For all these mentioned variants of the modular system there are described and simulated suitable control schemes. The issue of interleaved PWM is described in the thesis. Output voltage ripple and current ripple equations were derived for each converters connection. These equations, which were derived either for systems with interleaved PWM or for systems without of phase shifted PWM, are also proved by simulations. Design of reconfigurable modular system with power of 9.6 kW that contains four converters was introduced in this thesis. Converters use modern transistors and diodes of SiC material. The proposed reconfigurable modular system was successfully manufactured. The measurement results are also shown in the work.
22

Soběstačný domov pro 9000 obyvatel / Self-Sufficient Home for 9000 Inhabitants

Valový, Přemysl January 2014 (has links)
The objective of this diploma project is to propose a new self-sufficient city for 9000 inhabitants. The city as a phenomenon accompanying mankind for centuries has become an integral part of a physical and cultural heritage of our civilization. Accumulation of its population, ideas and material possessions always led to the remarkable act of creativity and efforts, that was always pushing mankind further. Nowadays cities are faced with a myriad of crises, both economic and social. However we shouldn't forget, with a view to the future, the impending ecological crisis. The rapid growth of the past is followed by a gradual decay in the current age. Moreover, in today's globalized society, the town becomes materially totally dependent on its surroundings. It drains resources from less developed land to feed its inhabitants. We can hardly predict consequences that would arise if these resources were cut off. With the precipitous pace of urban growth and migration of the world's population into densely urbanized areas* arise to us a question, if in these non-urban (agricultural) areas will be still somebody, who will nourish these future metropolis? * (since 2010, more than a half of the world population lives in cities) The aim to create a new self-sufficient city isn't a kind of compensation for contemporary cities, but an attempt to create a working model that would be generally applicable on a present towns. It should hint the way, which they could take to achieve self-sufficiency, less dependence on imports, functional community life reinforcing a higher unity and sophisticated environmental legacy for future generations. The goal of these efforts is not a "moving the population into this model city", but the movement of ideas from model town into existing cities.

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