Goal of this semestral thesis is to design power converter which is to be used for measurement. The converter consists of two forward converters in push-pull topology. The converter is to behave as a constant current source with maximum open-circuit voltage of 1000V. Maximum current is 5A. The current range is split into three sub-ranges, to meet the strict requirements on ripple current. The range of currents is 0-5A. The operating frequency of converter is 34KHz. The converter will be charged using two portable electric generators with output voltage 230V.

This master´s thesis describes switch mode power supply. The aim of this master´s thesis is the design and the construction of the switch mode power supply, which will be used as a laboratory tool.

This thesis deals with desing of serial resonant converter with regulation output voltage in full bridge configuration like alternative power switching converter with pulse width modulation. The thesis includes analysis of serial resonant converter, desing power transformer, driving circuits. The thesis concludes with the functional converter and complete technical documentation.

This thesis deals with the peripheral design, construction design and implementation welder DC arc. The concept of welder is based on the use of two single action forward converter working-pull. Converters operate at a frequency of 60 kHz. Output current can be adjusted in the range from 0 to 140 A. After switching function the welder can operate as a battery charger. Charging current can be adjusted in the range of 0-70 A. The device is powered from a single phase supply 230 V.

Tato disertační práce se věnuje studiu částečných výbojů (PD) způsobených poklesem spolehlivosti a životnosti elektronických zařízení a systémů. Diagnostika PD je dnes známá metoda pro vysoké napětí u vysoko-výkonných zařízení. V případě elektronických zařízení PD testování není ale běžně používáná metoda, přestože je zde také potenciál pro vysoké elektrické zatížení vzhledem k velmi krátké vzdálenosti. Tato práce je zaměřena na vyšetřování PD činnosti u elektronických zařízení. Bylo navrženo a provedeno pracoviště pro diagnostiku PD v elektronických zařízeních. Pracovní frekvence se pohybuje od několika stovek Hz až 100 kHz. Maximální amplituda PD testovaného napětí je vyšší než 10 kV. Navzdory jednoduché konstrukci toto zařízení přináší vysokou spolehlivost měření. Více než 300 PD testů bylo provedeno na různých elektronických zařízeních a elektronických součástí,např. na planárních transformátorech a elektronických komponentách používaných při vysoko-napěťových měničích

This work deals with high power pulse converters (tens of kW) using new semiconductor devices of silicon carbide (SiC). Firstly the current state of the issue is analyzed. A research in a specific area of high power buck converters with pulse transformer follows. There was a strong emphasis on minimizing size and weight. The design process was focused also on reliability and robustness. To achieve the defined objectives, it was necessary to use the latest available switching transistors and diodes, and an unusually high switching frequency (100 kHz at a power of about 16 kW). Due to the high switching frequency, we achieved small size of pulse transformers and output chokes. An optimization of high-frequency pulse transformer with demand on minimum volume and weight of core and windings represents a separate theoretical part of the thesis. There have been proposed several analytical solutions of optimization problems, the results of which could overlap with the implementation in practice of switching power supplies. The combination of high switching frequency, fast semiconductors and the high power brings various parasitic effects to the power circuit. In the thesis, these parasitic effects are analyzed. Solutions which minimize or completely remove those effects were theoretically designed and successfully implemented, tested and finalized in experimental part of the work. Detailed description of the implementation of functional sample and series of validation measurements are included in the final part.

This master´s thesis with the peripheral and structural design of power converter that will be used for DC welding. The drive itself is based on the principle of two single-acting permeable converters operating in counter strokes to a mutual load. The inverter operates at a frequency of 60kHz, and its output current can be controlled from 0 - 100A. Welder is equipped with a variable constant current or power adjustment. The device is powered from a single-phase 230V.

This thesis contains a complete description of the design and implementation of a 500W transformer soldering station. This soldering station includes a half-bridge DC/DC converter with a pulse transformer. The device works with a very low voltage and extremely high output current. Therefore some parts have a special design to ensure the proper equipment function. Coaxial transformer with very low leakage inductance (nH units) is unusual. A synchronous rectifier is another special feature working with low voltage and high output current of the transformer. The finished functional prototype consists of a soldering station and a soldering adapter.

The presented thesis is focused on knowledge extension in the area of partial discharge measurements and evaluation at frequencies higher than 1 kHz. The thesis includes the design and set up of the measuring workplace equipped for measuring partial discharges, including the methodology of the measuring and calibration procedures necessary for the achievement of reproducible results. Another part of the thesis deals with the technology of acoustical and electromagnetic sensors convenient for the diagnostics and localization of partial discharges in devices, that work at voltages above 500 V. Electrical circuits that enable data evaluation by using the signal from a sensor working on amplitude analysis principle were developed. For PD detection a PC controlled measuring device working on amplitude analysis principle had to be designed and realized. The possibilities of the workplace have been demonstrated in the process of development of the insulating systems for pulse transformers. Thesis results can significantly contribute to a higher quality of newly designed electronic devices and systems working at voltages above 500 V.