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Optimization of use properties Lead-Acid batteries
Lábus, Radek ; Dostál, Zdeněk (referee) ; Jareš, Petr (referee) ; Křivík, Petr (advisor)
This thesis focuses on the limitations of degradation mechanisms of Lead-Acid batteries, which significantly contributes unequal distribution of current (and therefore internal resistance, charge passed and power loss) on the surface of the electrodes of Lead-Acid battery. The unevenness of distribution of these parameters significantly influences the distribution of current tabs on the electrodes. In this work it was developed realistic model of Lead-Acid battery cell with plate electrodes with different variants of the distribution of current tabs. Measured results obtained in this model were compared with the results found out from the mathematical simulations. Through these simulations, it was possible to take a look deeply into the processes and changes in the electrodes of Lead-Acid batteries during discharge. Goal of this work was for predefined variants of positioning of the current tabs to simulate distribution of current, internal resistance, charge passed and power loss during discharge. Another goal was to compare the different variants and to find the optimal variant of current tabs positioning based on minimizing of unevenness of examined variables distribution.
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Control unit for BLDC motor
Krejčí, Ondřej ; Cipín, Radoslav (referee) ; Procházka, Petr (advisor)
This master„s thesis elaborates with EC motors problematic. There are described essential features of brushless DC motors, their principles, construction and methods for rotor position detection. There are mentioned commonly used control algorithms of EC motors including theory of three-phase convertors. This thesis also contains a complex design of the universal convertor for EC motor and its practical implementation. Power parts losses calculation, heat-sink calculation and measurements at the convertor prototype are also described in this thesis.
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Hardware design of diesel injection system control unit
Novák, Matyáš ; Háze, Jiří (referee) ; Šteffan, Pavel (advisor)
This master’s thesis deals with the basic design of diesel injection control unit hardware. There is a description of the whole blocks of Motorpal Common Rail diesel injection system in the introduction. Next are described requirement of control unit hardware. In the following are descriptions of parts, which was choosed for adjustment. The second part of thesis describes the whole design of control unit wiring diagram. There is described each block in detail in this part. Next part describes component placement on printed circuit board. The conclusion of thesis compare designed version of control unit with elderly versions.
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Automated calculation of resistance crucible furnace design
Míček, Radoslav ; Baxant, Petr (referee) ; Lázničková, Ilona (advisor)
In the main part of the bachelor’s thesis is primarily elaborated the question of electrical resistance heating in common terms, that means, that the fundamentals of both basic types of resistance heating are explained, and then the applications of resistance heating on different kinds of electric furnaces, eventually other electroheat equipments are mentioned. Seeing that the bachelor’s thesis is in the main oriented on indirect resistance heating, is the next part of this work devoted to heating elements, which are one of the basic parts of electroheat equipments, that utilize indirect resistance heating. There are specified materials most frequently used in heating elements production, including their properties. Some sections deal also with their construction. In the next chapter, there are mentioned the basics of electric resistance furnace proposing. Especially there are heat calculations (furnace total input, charge soaking time or other basic parameters of the furnace) and electric calculations, whose goal is to determinate parameters of heating elements. The last part of the bachelor’s thesis considers a true project of aluminum melting crucible furnace. Except the other furnace parameters (general input, accumulated heat, furnace rise time etc.) discusses it especially the choice of heating elements materials and the calculation of heating spiral parameters, that means wire length and diameter, external diameter of spirals and lead of screw thread. At first are mentioned common relations and next comes an example of crucible furnace calculation with concrete parameters and requirements. The bachelor’s thesis includes a programme for computerised calculation of crucible furnace project created in Microsoft Office Excel application.
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Transient Thermal Response Measurements
Stejskal, Martin ; Čala, Martin (referee) ; Beneš, Petr (advisor)
This Bachelor thesis is interested in measurement of thermal parameters of three-phase power switching module. The module contains IGBT power transistors and power diodes, whose dynamic parameters are measured. Based on these measurements, substitute thermal models are constructed, necessary for heat loss simulations and calculations.
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Class H audio power amplifier design
Spáčil, Tomáš ; Šebesta, Jiří (referee) ; Dušek, Martin (advisor)
This bachelor´s thesis is dealing with a plan of a low frequency ending amplifier of class H that is made of discreet parts. Content of this work is an explanation of basic terms and classes of ending levels low frequency amplifiers. The ending level in class H is written in detail including its possible kinds of solution. The own solution of amplifier in class H is completed by simulation and areal connectors to individual parts. The aim of this work is a prototype of a final look of a device with record about measurement of its basic qualities and their evaluation.
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Simulation of circuit-breaker trip unit
Dostál, Lukáš ; Augusta, Zbyněk (referee) ; Valenta, Jiří (advisor)
Securing of electrical devices is important not only to protect against destruction under the effects of electric current, but also for protection of people or animals against electric shock. With increasing of living standards goes hand in hand increasing of the electricity consumption. Therefore In the grid of low voltage, there are increasing short-circuit currents. With improving technology is posed considerable demand on the performance, security and switching capacity of circuit breakers. This thesis is oriented on development of thermal and electromagnetic switch of circuit breaker on which is put a big demand in development of new types of circuit breakers. The thesis is interesting because of comprehensive use of circuits’ breakers since it can be used in AC and DC networks with frequency of 50 Hz and 400 Hz.
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Analýza jízdních odporů osobního automobilu
Doležal, Ondřej
The thesis is devoted to the analysis of road resistances of a car. The first part deals with the theory of individual road resistance which counteracts the movement of the car. The chapters are given the formula for calculating individual road resistance and in the end is mentioned relationship of total road resistance. The second part is focused on the construction of tires, their signs and detailed description dimensions. This section also describes a tire according to the shapes of designs, their type and how to properly store them. The next part explains the theory of rolling the vehicle wheel according to the type of pads. The penultimate section describes the methodology for measuring the road resistance in real traffic. The conclusion describes experimental measurements of passive losses car at various inflation pressures made on vehicle testing institute of technology and automobile traffic. In this passage it is also a graphical and verbal evaluation of practical measurement.
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Transient Thermal Response Measurements
Stejskal, Martin ; Čala, Martin (referee) ; Beneš, Petr (advisor)
This Bachelor thesis is interested in measurement of thermal parameters of three-phase power switching module. The module contains IGBT power transistors and power diodes, whose dynamic parameters are measured. Based on these measurements, substitute thermal models are constructed, necessary for heat loss simulations and calculations.
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