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Inverter for arc welding
Matiaško, Maroš ; Huták, Petr (referee) ; Vorel, Pavel (advisor)
This bachelor’s thesis describes designing, paremeter rating and construction of welding source on the principle of high-frequency inverter. The main scope of work is to design a switching inverter for arc welding on the principle of the forward converter. Welding source is regulated for demand of constant current.
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Complete design of three-way speakers
Jalový, Michal ; Petržela, Jiří (referee) ; Slezák, Josef (advisor)
This project describes complete design of Three-way speakers. The introduction discussed the basic theoretical knowledge to the understanding of loudspeaker system design issues with regard to the physiology of hearing, the theory of acoustics, speaker characteristics, types of enclosures and the use of switches. Furthermore, based on the formula calculated parameters of a loudspeaker cabinet and speaker points to the loudspeaker of the proposed speakers.The proposal also relies on the specific measurement properties of the selected speaker impedance. Finally all data are presented for practical implementation speakers.
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Optimization of the switching power supplies with synchronous rectifier
Skácel, Josef ; Macháň, Ladislav (referee) ; Žák, Jaromír (advisor)
This thesis deals with switching circuit topic, especially switching power supplies. There are switching circuits without inductance and their benefits presented in the thesis. Basic topologies of switching power supplies, their properties, application area and functions of basic types of converters are also described. The next section focuses on special resonant switching power supplies and synchronous. The main part of the work is carried out simulations using three synchronous rectifiers. The work includes practical design of an SMPS with synchronous rectifier.
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Step-Up converter for mobile device
Gabriel, Petr ; Červinka, Dalibor (referee) ; Huták, Petr (advisor)
The purpose of this bachelor‘s thesis is about to intoduce possibilities of construction and use of switched power supplies. Thesis focuses mainly to description of different types of converters. There are possibilities of power supplie's design and sizing of its components described in this thesis. This thesis contains concrete design of power supply for realization. There are results of the measurement and comparision to the parameters given by manufacturer set forth at the end of this thesis.
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Four-electrode impedance plethysmograph
Port, Martin ; Kolář, Radim (referee) ; Chmelař, Milan (advisor)
This master’s thesis is an introduction to the measurement of changes in tissue impedance of blood flow by impedance plethysmography. Other chapters deal with the kinds of plethysmographs and their principles. The aim is to draft four-electrode impedance plethysmograph to measure changes in tissue impedance depending on blood flow. First, describe the individual blocks of the medical instrument. The practical part of the master’s thesis involves circuit design four-electrode plethysmograph. Given that a very important role in its function plays a constant current source operating at a frequency of 60kHz, this subset was implemented and verified its correct function. To draw component schemes used program EAGLE version 5.10.0.
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Switching driver for high power LEDs with higher efficiency
Doležal, Miroslav ; Háze, Jiří (referee) ; Šteffan, Pavel (advisor)
Problems in swithing converter and power losses in this circuit describe these master’s theses. Power losses have the primar influence on the total effectivity circuit. The first chapter deal swith principle of basic parts switching converter (buck, boost, buck-boost). The power losses on main elements used in switching circuit (diode, transistor) are explained in the next part this thesis. Theory of synchronous rectifiction for reduction of losses. A choice of two integrated circuit useful for future design of LED driver working in buck-boost mode is on the end of the theoretical part. The practical part is fosud on the design of circuits (with integrated circuits chose in the theoretical part) including schematic diagram, calculation of parts and PCB layout. The build samples are evaluated by set of measurements in the field of effeciency, temperatures of components, stability output LED current, EMC and soon. Finally the particular parameters of both tested circuits are compared
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Switching supply source 5,5kV/4,3kW with silicon-carbide semiconductors
Gabriel, Petr ; Patočka, Miroslav (referee) ; Vorel, Pavel (advisor)
This thesis is about to introduce the development of switched power supply with output voltage of 5,5 kV and power of 4,3 kW. This thesis directly follows the outputs of two previous semester projects. Main task is about to finish the development of remaining printed circuit boards and perform launching of all parts of developed power supply. Next necessary task is about to assemble a functional prototype of the supply using the developed parts, performing a series of measurement supply’s parameters and creating of technical documentation of mechanical part. There are all stages of supply’s development included in this thesis. From the first part, that describes various types of converters, through the design of all the supply’s parts, to final implementation of functional prototype. There are the results of measurement supply’s parameters at the end of this thesis.
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Step-down converter with variable output voltage in range from 20 to 100 V
Pazourek, Petr ; Šmirg, Ondřej (referee) ; Hanák, Pavel (advisor)
This master's thesis describes the design and the implementation of a step-down converter with variable output voltage for laboratory purposes. In the introduction the basic functions of switching power supplies are shown, flyback, forward and push-pull converters are described, followed by some integrated circuits for power management of converters. The second chapter discusses in detail the design of requested switched power supply, including the calculation of the electronic parts and design of the storage inductor. Following are described some observations of building this power supply, including the output characteristics. In conclusion, the obtained results are assessed, including proposals to improve whole design.
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High Voltage Pulse Generator for Electroporation of Cells
Puczok, Václav ; Martiš, Jan (referee) ; Červinka, Dalibor (advisor)
The main goal of this thesis is to design control board for the experimental electroporation device and to develop control firmware. The first chapter of this work focuses on the electroporation phenomenon itself. Behaviour of the cell model in external electrical field is described there as well as simulation and overview of how electroporation affects living tissue. It also explains the main requirements for parameters of the electroporation pulses as well as need for ECG synchronization. Furthermore, some remarks are given about novel high frequency electroporation method, which involves use of nanosecond bipolar high voltage pulse bursts. The second chapter briefly introduces commercial electroporation device called Nanoknife, including control part, power part, and it's limits. The third chapter consists of introduction of the novel experimental electroporation device developed at BUT. Power part of this device is discussed as well. Next chapter focuses on design of the control board for this device and also on description of the particular schematic parts. There is a control algorithm explanation in the fifth chapter of this thesis followed by the brief manual to machine operation.
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