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Welding inverter
Lizúch, Ján ; Vorel, Pavel (referee) ; Martiš, Jan (advisor)
The aim of a masters thesis is to design components, circuits and to build welding power source. Description and technological process of welding, arc characteristic and welding methods requirements are included in a first part of the thesis. Switching mode power supply topologies are characterized in a next part of the thesis. At the end of a theoretical part, the parameters of welding power source are determined. Its design is described in the next parts of the thesis where calculations and design process of electrical part is described. There are also schematics of circuits shown. In each power part is power dissipation calculated, what is needed to design cooling. Practical build and tests of welding power source are described in the last part of thesis. Measured waveforms and thermal camera images during load test are included in the last part as well
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A traction drive for an electric bike with motor "Heinzmann"
Němec, Petr ; Huták, Petr (referee) ; Vorel, Pavel (advisor)
This work deals with a proposal and construction of a DC/DC converter for a control of a DC motor Heinzmann. The DC/DC converter will be used in an electric drive for a bicycle. The proposal of the DC/DC converter is designed for such engine power to avoid fully any human force to drive - pedaling. The work includes informations about the used motor, progress of proposal and dimensioning of the converter - power circuit and control electronics.
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Switching loss reduction in the switch-mode supplies
Vašíček, Adam ; Vorel, Pavel (referee) ; Patočka, Miroslav (advisor)
The master's thesis covers in its first parts origins and consequnces of the switching losses, basic principles of the various resonant tanks and resonant DC/DC converters. Afterwards the innovative approach of the multiperiod modulation is presented. The main advantages of this kind of modulation include very wide zero current switching region and lowering the switching frequency as the output voltage decreases. In the remaining part of the thesis a prototype converter design is described.
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Power Converter for the electric DC arc welding
Vranák, Daniel ; Vorel, Pavel (referee) ; Patočka, Miroslav (advisor)
The main aim of thesis was produce a draft power converters for DC arc welding, which would be suitable for use in regular service. For the purpose of the proposal, first must be acquainted with the possible methods used converters whose distribution and explain the principle place in beginning thesis. Next it was transferred detailed design of individual components, which was used for the construction of the power part of the welder.
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Bycicle with Combustion Engine and Electrical Transfer of Power
Mazálek, Tomáš ; Huták, Petr (referee) ; Vorel, Pavel (advisor)
The objective of this semester thesis is design of the control algorithm, needed control and power circuits and PCB design for the unfinished bicycle concept with a combustion engine and electric power transmission. The control algorithm had to be designed to make efficient use of the combustion engine performance and to minimalize the fuel consumption and noise level of the device. All circuits are fully implemented by analog components for which were designed printed circuit boards using program Eagle and this boards were revived and debugged.
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Electric motorbike traction drive
Bartoš, Jiří ; Vorel, Pavel (referee) ; Martiš, Jan (advisor)
This work deals with complete designing of electric drive for lightweight motorcycle. There are mentioned options of electric drive and types of batteries. One solution for Jawa 50/555 motorcycle frame is picked. In this work are measured losses of traction motor and cooling system is modified. There are some necessary calculations of drive. In next part 10S6P Li-ion battery with balancer and undercharge controller is realized. In this thesis design of step – down converter with current control is described, cooling and PCB is proposed. Complete converter with cover is made.
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Calculation of optimum slip frequency of induction motor for minimisation of its losses
Bednařík, Václav ; Patočka, Miroslav (referee) ; Vorel, Pavel (advisor)
This master’s thesis focuses on the minimisation of losses by calculation of optimum slip frequency of induction motor. The next point of this master‘s thesis is supersaturation. Supersaturation must be solved for the size of losses, because of the effect that is cause of the losses, when current increases with saturation. However current is not increase proportionally with increasing saturation, but increases several times more. This problem is included in the calculation of the slip frequency. Optimum of slip frequency is solve for modified gamma model of induction machine. In the main point of this thesis is outlined the process, how the optimum can be found. With same process were already were found the equations, but they were too extensit. In the end is solved the optimum of slip frequency be minimum of the flux density.
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