National Repository of Grey Literature 78 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Efficiency Improvement and Optimization of High Power Switching Converters
Martiš, Jan ; Dudrik,, Jaroslav (referee) ; Peroutka,, Zdeněk (referee) ; Vorel, Pavel (advisor)
This thesis focuses on optimization and increasing the efficiency of high-power DC/DC switching converters with transformer (switching power supplies). The work focuses mainly on using converters with flyback topology for high power, even though it is a common belief that this type of converter is not suitable for high power. This topology was selected because of potentially better achievable parameters, especially the efficiency, in comparison to a commonly used forward converter – in a flyback converter, losses are produced only in one magnetic component (transformer) in contrast to two components (transformer and inductor) in the forward converter. Compared to resonant and quasi-resonant converters, the flyback converter is easily controllable in the whole output voltage and current range. To make the flyback converter favorable for a high-power use, some innovative circuit modifications were made and modern semiconductor and passive components were used. Theoretical part of the work deals with efficiency optimization of the flyback converter, based on analytical solution. Operating parameters of the converter – switching frequency and parameters of the transformer (flux density and numbers of turns) are commonly only guessed or chosen from experience. The objective of this part is a mathematically exact determination of these parameters to achieve lowest total losses of the converter for given input parameters. In a certain case, it was possible to obtain the final solution analytically, in other cases the final solution step had to be done with a help of software. A prototype of a 12-kW switching power supply with a flyback converter was constructed to validate the proposed solutions and methods. The power supply fits into a space of only 33x33x16 cm. Modern semiconductors based on the silicon-carbide (SiC) technology (MOS-FET transistors and diodes) were used. After bringing the converter to a full-power operation, an efficiency of 96.8 % of the DC/DC converter was measured. High efficiency was obtained for a wide range of output parameters. A certain comparison with a forward converter with the same output parameters is done in the work. Not only from an efficiency point of view, the flyback converter seems very perspective.
Electromagnetic power actuators
Kadlecová, Lucie ; Vorel, Pavel (referee) ; Folprecht, Martin (advisor)
This master thesis focuses on literature research of problematics linked to power actuators working on electromagnetic principle to accelerate metal projectiles. It’s goal is mathematical analysis and constuction of selected type of electromagntic power actuator – induction coilgun
DC/AC one-phase inverter 230 V / 50 Hz / 60 VA for a back-up supply source with a galvanic separation
Šoupal, Ondřej ; Procházka, Petr (referee) ; Vorel, Pavel (advisor)
The aim of this thesis is to design power circuits and control circuits of single phase DC/AC inverter and its practical realization. This work describes basic principle of single phase inverter. Next step is a solution of output LC filter, input capacitor and semiconductor devices. It contains block diagram of control circuits and it focuses on design of oscillator for pulse width modulation and current limiting. The thesis gives details about practical realisation and testing measurements. Technical documentation was prepared for this inverter.
Parameter analysis of an induction three-phase machine with a wound rotor
Porubský, Ondrej ; Knobloch, Jan (referee) ; Vorel, Pavel (advisor)
This bachelor thesis describes the general principle of induction motor operation in the first part. The second part deals with the renovation of the historic motor rotor winding further describes the measurements needed to calculate motor parameters and their analysis.
DC/DC converter for car-audio amplifier
Šmarda, Vladislav ; Vorel, Pavel (referee) ; Červinka, Dalibor (advisor)
This Bachelor thesis deals with the design and construction of a resonant switching power supply for car audio-amplifier. The main subject of the theoretical part is the mathematical description of the applied ZVCS Push-Push topology. Also a general guide, for designing this type of topology is mentioned. There is described the optimalization procedure of the main switch mode power transformer with respect to the high efficiency of the proposed power supply. Then the designed power supply is made and tested.
Electronic ballast for sodium lamp
Eliáš, Jaroslav ; Vorel, Pavel (referee) ; Huták, Petr (advisor)
The aim is to get acquainted with the way the management and regulation of sodium lamps. This knowledge is then applied to design your own gear. The introductory section describes the basic characteristics of discharge light sources. Their behavior was verified by measuring and findings were used to create diagrams, mainly the control circuit. Theoretical design is developed by individual functional parts of the inverter.
DC/DC converter 24 V / 320 V / 60 W for a back-up supply source with a galvanic separation
Dvořák, Petr ; Martiš, Jan (referee) ; Vorel, Pavel (advisor)
This bachelor‘s thesis deals with the design, dimensioning and realization of a DC/DC 24 V / 320 V converter with a output power of 60 W. In the first part there is a short description of the linear stabilizer and then the switching sources with their dismemberment. Based on that chapter, was selected the flyback converter. The second part deals with components design and description of the control circuit. At the end, the construction of the converter with the verification measurement records is shown.
Soldering gun with Li-Ion battery supply
Bartoš, Miroslav ; Vorel, Pavel (referee) ; Martiš, Jan (advisor)
This master‘s thesis deals with the design of battery powered soldering iron. The soldering iron will be placed in the plastic box from a conventional transformer soldering iron. First, we need to find the parameters of the original transformer soldering iron. Then design a synchronous step-down converter, driver of converter, BMS circuits, and component placement in a plastic box. The battery-powered soldering iron was successfully revived and tested, the final parameters of the converter are: voltage 0.4 V at 80 A current. The total power on the soldering wire is 32 W. Technically, this is a very interesting alternative to the classic version of the soldering iron, which can be used for assembly or repairs in poorly accessible locations.
System of DC/DC converters for solar cells of a fotovoltaic power plant
Benda, Dušan ; Huták, Petr (referee) ; Vorel, Pavel (advisor)
This master thesis describes the design of a DC/DC converter for one photovoltaic panel with a 250 W peak power. The master thesis is divided into parts dealing with detailed design of power electronics, analog circuit design, description of control MPPT algorithms and software for control circuit. The chapter with the mathematical modeling of the converter created in the Matlab Simulink was added beyond the assignment.
Bicycle additional drive with a combustion engine and an electric powertrain
Doležal, Lukáš ; Pazdera, Ivo (referee) ; Vorel, Pavel (advisor)
The objective of this master's thesis is new power converter design for bicycle with combustion engine and electric power transmission. The power converter is control by microprocessor and control algorithm is designed to achieve maximum efficiently of combustion engine. Converter and servomotor for controlling combustion engine throttle are located in metal box. Hardware, firmware and metal box are designed in the thesis.

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