National Repository of Grey Literature 84 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Single-phase DC/AC converter with output parameters 230 V / 50 Hz / 100 VA
Smolák, Martin ; Martiš, Jan (referee) ; Vorel, Pavel (advisor)
This master‘s thesis focuses on optimization of power and control circuits of an inverter, which was developed at UVEE. The principle of function and circuit implementation of a single-phase inventer, various calculations (design of an LC filter, DC link capacitor, semiconductor elements and heat sink) are described in the thesis. A design of fast overcurrent protections, oscillator and saw signal generator is included. Furthermore, a printed circuit board was designed which was optimized by thermal simulation in the Workbench Ansys. Subsequently, the printed circuit board was mounted, debugged and verification measurements were performed on it. At the end of the thesis there is a documentation for the implemented equipment.
DC/DC converter 24 V / 350 V / 100 VA with a pulse transformer
Pár, Lukáš ; Huták, Petr (referee) ; Vorel, Pavel (advisor)
This diploma thesis deals with design of DC/DC converter which will be used in one-phase inverter powered from batteries. Required parameters are output power of 100 W, input voltage of 24 V and output voltage of 350 V. In the first part is briefly discussed used topology of flyback converter. In the next part is designed impulse transformer with a request to design impulse transformer as small as possible. Thesis continues with draft of power components placed on primary and secondary side of converter. In this thesis is part about limitation of voltage overshoot at turn off transistor. Next part of this thesis deals with the design of control circuits using an integrated circuit from the UC384x family. Thesis continues with the production and debugging of the converter. At the end of this thesis are measurements confirming the correctness of the proposed design.
Fast-charger for lead-acid batteries 12 V
Kopuletý, Ondřej ; Pazdera, Ivo (referee) ; Vorel, Pavel (advisor)
This Master thesis deals with modification of lead battery charger connection. In particular, changes are made to the control board. The theoretical part describes the principle of charging lead batteries and the description of the basic types of switching power supplies. Furthermore, the dimensioning of important components in the circuit together with the optimization of the switching frequency and the parameters of the high-frequency transformer are also presented. At the end of the thesis is the procedure of assembling the whole charger.
Wireless power transfer 20 kW
Tománek, Radek ; Vorel, Pavel (referee) ; Martiš, Jan (advisor)
This thesis deals with the design of wireless power transfer at a distance of 600 mm dimensioned to 20 kW. The transfer is provided by inductive coupling of resonant circuits with 800 mm diameter coils. It contains a description of the design and calculations of individual parts, stating specific values. It also includes description and schematics of control circuits.
Full bridge DC-DC converter with transformer
Boháček, Daniel ; Vorel, Pavel (referee) ; Folprecht, Martin (advisor)
This semestral thesis deals with the issue of full bridge DC-DC convecter with transformer. The aim of this semestral thesis is the design, construct and verification of functionality convecters, which will be used as laboratory tool.
Battery-powered welding inverter
Starec, Stanislav ; Folprecht, Martin (referee) ; Vorel, Pavel (advisor)
This semester’s paper is focused on proposition and following implementation of DC arc welder. This paper is based on master thesis, where the first version was realized. The welder is powered by a battery pack with LiFePO4 type cells. Battery cells are protected by BMS circuits. The driving electronics controls the duty cycle step-down (buck) converter in a closed current or power regulation loop. The power regulator has been designed and validated by simulations. Switching power transistors, low side and high side, are implemented by optically isolated gate drivers. Charging the battery is solved by a switching flyback converter. For the charger and the welder is sheet metal construction made of aluminum sheet.
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.

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