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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Historický vývoj a současná úprava přídavků na dítě / The historical development and present regulation of a child benefit

Boldys, Zbyněk January 2011 (has links)
Historical development and current regulation of the child allowance in the Czech Republic This thesis describes the development of monetary social allowance paid by state to dependent children. The work revealed that the child allowance is relatively new legal institution first recorded in 1922 in the act that increased incomes of government employees and their family members implicitly. This fact has appeared as a disadvantage of the thesis as it is difficult to define it in comparison to other traditional legal institutions determined, adapted and accepted from Roman law jurisprudence. The thesis deals with the child allowance defined in current legislation as well as with a former education allowances that were of the same form and the current allowances are based on this type. It is abstracted from the chronological outline of the first part as well as the content of the rights and obligations of entities associated with these allowances as well as the common body - the monetary support from the state used for dependent children. An identical object and the rights and obligations arising from it can be found in the content of similar allowances, but due to the extent of the theses there were no possibility to include these in the text. The thesis is divided in two parts. The first part...
2

Nízkofrekvenční aktivní umělá zátěž / Low frequency active artificial load

Lízner, Václav January 2017 (has links)
This diploma thesis is focused on synthetic loads, especially electronically controlled loads. The thesis analyse principles of mechanically and electronically controlled loads and theirs operation modes. The paper also carried out a search of AC loads available on the market. The parameters of the AC load were based on the requirements provided by client. The functionality of the designed load is verified by simulation. The thesis continues with realization of the designed schematics and bringing the load to function. At the last section of the thesis are detail parameters of the designed load verified by measurement.
3

Driver Circuit for White LED Lamps with TRIAC Dimming Control

Weng, Szu-Jung 25 July 2012 (has links)
An efficient Light Emitting Diode (LED) lamp driver circuit is proposed for retrofitting the conventionally used incandescent lamps with existing TRIAC dimmer. The dimming feature in a wide range of firing angle from 30¢X to 130¢X can be accomplished by means of double pulse-width modulation (DPWM) and analog current regulation. The LED lamp driver adopts a flyback converter with an auxiliary active power MOSFET for synchronous switch and an associated inductor for zero voltage switching (ZVS), leading to lower switching loss and thus achieving a higher circuit efficiency. In the thesis, the mode operation of the driver circuit is analyzed and the design equations are derived accordingly. A laboratory circuit is designed for an 50 W LED lamp which is composed of 45 high-brightness white LEDs in series. Experiments are carried out to test the circuit performances with two dimming schemes. The experimental results indicate that the driver can achieve a circuit efficiency of 95 % at the rated output. When the LED lamp is dimmed, the circuit efficiency with DPWM is higher than that with the analog current regulation. On the other hand, the LED lamp dimmed by analog current regulation has a higher efficiency but a less color shift by DPWM.
4

Evaluační platforma s integrovanými obvody pro řízení LED světlometů / LED Driver evaluation kit for Automotive Front-Lighting

Večeřa, Jindřich January 2020 (has links)
This thesis deals with design of evaluation platform for integrated circuit NCV78934, which is designed to control LED headlights in automotive industry. The theory concerning the current regulation of buck converter, schematic design, PCB design and software design are also included in the thesis. Finally the measured data and testing procedures of the designed evaluation platform are discussed.
5

Návrh měniče pro BLDC motor / Design of a convertor for a BLDC motor

Stejskal, Martin January 2017 (has links)
This master thesis deals with the design and realization of a drive for a 500 W BLDC motor powered with a battery power supply. It also deals with the possibilities of realization of drives and other possibilities to control these motors. Describes the implementation of the inverter using Atmel's AVR microcontroller. The thesis also deals with the design of an auxiliary switching inverter. Communication with UART and CAN interface is also implemented.
6

Parallel Active Filter Design, Control, And Implementation

Ozkaya, Hasan 01 June 2007 (has links) (PDF)
The parallel active filter (PAF) is the modern solution for harmonic current mitigation and reactive power compensation of nonlinear loads. This thesis is dedicated to detailed analysis, design, control, and implementation of a PAF for a 3- phase 3-wire rectifier load. Specifically, the current regulator and switching ripple filter (SRF) are thoroughly investigated. A novel discrete time hysteresis current regulator with multi-rate current sampling and flexible PWM output, DHCR3, is proposed. DHCR3 exhibits a high bandwidth while limiting the maximum switching frequency for thermal stability and its implementation is simple. In addition to the development of DHCR3, in the thesis state of the art current regulation methods are considered and thoroughly compared with DHCR3. Since the current regulator type determines the SRF topology choice, various SRF topologies are considered and a thorough design study is conducted and SRF topology selection and parameter determination methods are presented via numerical examples. Through a PAF designed for a 10kW diode/thyristor rectifier load, the superior performance of DHCR3 is verified through simulations and experiments and via comparison to other current regulators. The sufficient switching ripple attenuation of the SRF structures for the designed PAF system and the overall performance of the designed and built PAF system are demonstrated via detailed computer simulations and laboratory experiments. This thesis aids the PAF current regulator and SRF selection, design, and implementation.
7

Měnič pro svařování stejnosměrným proudem / Converter for DC Welding

Siuda, Petr January 2016 (has links)
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.
8

Étude et conception d'un groupe motopropulseur électrique à faibles niveau vibratoire et sonore pour véhicule électrique. Aspects "contrôle - commande" / Study and design of an electric powertrain with low vibration and noise levels for electric vehicles. "Control – command" aspects

Arab, Mohammad-Waseem 30 September 2015 (has links)
Dans un contexte mondial régi par de multiples facteurs économiques, énergétiques et environnementaux, la transition vers des modes de transport à zéro émission polluante semble inévitable. De ce fait, les constructeurs automobiles s’investissent de plus en plus dans le développement de groupes motopropulseurs électriques afin d’anticiper les besoins du marché. Parmi les différentes technologies de machines électriques considérées pour cette application, la Machine à Réluctance Variable à Double Saillance (MRVDS) présente des caractéristiques très attractives pour le milieu industriel.Les travaux présentés dans cette thèse visent à élaborer des solutions qui répondent aux points qui bloquent encore l’adoption de la MRVDS dans les véhicules électriques. Dans un premier temps, la commande en couple d’une MRVDS destinée à la traction électrique est analysée. En prenant en considération les exigences imposées par l’application envisagée, une stratégie de commande en couple est développée en intégrant deux méthodes complémentaires sur le plan de fonctionnement de la MRVDS choisie.Dans la deuxième partie, l’asservissement en courant est abordé. Les problématiques du contrôle propres à la MRVDS à forte dynamique de courant sont d’abord identifiées. Ensuite, deux régulateurs de courant, qui répondent à différents conditions d’implantation, sont présentés et validés par simulation.La dernière partie de cette thèse aborde le problème des à-coups d’accélération induits à basse vitesse et de leurs répercussions sur l'agrément de conduite. En effet, ce type de motorisation électrique introduit un nouvel aspect sur cette problématique. Une loi de commande anti-à-coups, composée de deux actions, est développée. Les simulations ont montré la conformité de la performance obtenue en utilisant la loi de commande proposée avec le cahier des charges industriel visé. / In a global context governed by multiple economic, energetic and environmental factors, the transition towards transportation modes with zero polluting emissions seems inevitable. Hence, automotive manufacturers are investing increasingly in the development of electric powertrains in anticipation of the market needs. Among the different electric motors technologies considered for this application, the switched reluctance motor (SRM) presents attractive characteristics for the industry.The work presented in this thesis aims to elaborate solutions in response to the points still hindering the adoption of the SRM in electric vehicles. First, torque regulation of an SRM intended for an electric traction is analyzed. Taking into consideration the requirements of the application in hand, a regulation strategy is developed through the integration of two methods which complement each other over the studied SRM range of operation.In the second part, the subject of current regulation in the SRM is discussed. The issues related to current regulation in SRMs disposing of high current dynamics are firstly identified. Then, two current regulators, each adapted to different implementation conditions, are presented and validated through simulations.The last part of this thesis discusses the acceleration jerks induced at very low speeds and their repercussions on driving comfort . Indeed, electric traction introduces a new aspect on this rather classic issue. An anti-jerk control law, composed of two control actions, is developed. Simulations have shown the conformity of the performance obtained with the proposed control law with the target industrial specifications.

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