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Mylonas, Georgios. "Programmable voltage reference generator for a SAR-ADC." Thesis, Linköpings universitet, Elektroniksystem, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-98567.
Повний текст джерелаАнотація:
SAR-ADCs are very popular and suitable for conversions up to few tens of MHz with 8 to 12 bits of resolution. A very popular type is the Charge Redistribution SAR-ADC which is based on a capacitive array. Higher speeds can be achieved by using the interleaving technique where a number of SAR-ADCs are working in parallel. These speeds, however, can only be achieved if the reference voltage can cope with the switching of the capacitive array. In this thesis the design of a programmable voltage reference generator for a Charge Redistribution SAR-ADC was studied. A number of architectures were studied and one based on a Current Steering DAC was chosen because of the settling time that could offer to the Charge Redistribution SAR-ADC switching operation. This architecture was further investigated in order to spot the weak points of the design and try to minimize the settling time. In the end, the final design was evaluated and possible trimming techniques were proposed that could further speed up the design.
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Alla, Ravi Chandar. "Design and Implementation of an analog to digital conversion mechanism for an in-situ monitoring microelectrode SOC." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1227042824.
Повний текст джерела
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Laotaveerungrueng, Noppasit. "A High-Voltage, High-Current Multi-Channel Arbitrary Waveform Generator ASIC for Neural Interface and MEMS Applications." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1291675462.
Повний текст джерела
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Liu, Jingbo. "Modeling, analysis and design of integrated starter generator system based on field oriented controlled induction machines." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1132763176.
Повний текст джерела
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Baggu, Murali Mohan. "Advanced control techniques for doubly fed induction generator-based wind turbine converters to improve low voltage ride-through during system imbalances." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2009. http://scholarsmine.mst.edu/thesis/pdf/Baggu_09007dcc806684bd.pdf.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Missouri University of Science and Technology, 2009.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed May 27, 2009) Includes bibliographical references (p. 126-130).
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Weissbach, Joel. "Measuring forces on a hydropower generator using strain gages." Thesis, Uppsala universitet, Elektricitetslära, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-256575.
Повний текст джерелаАнотація:
Increased awareness concerning our energy consumption and its environmentaleffects, has led to a high demand for renewable energies. Hydropower providesaround 40 percent of the electric energy consumed in Sweden today. If energyefficiency and production time were to increase only by some percent in thehydropower plants, vast amounts of additional renewable energy could besupplied to the electric grid. The Hydropower group at Uppsala University usesa hydropower generator to localize and decrease some of the power losses andthe wearing in the generator. New equipment is being tested and evaluated onthe generator. By measuring static and dynamic forces in the generator broaderinsight can be reached during these tests. This thesis describes the development of a system measuring forces on ahydropower generator using strain gages. Each sensor node is equipped withfour strain gages and a signal conditioning circuit. The system measures strain inthe generator, converts it to a voltage signal, amplifies it, filters and transmits it.After calibration of the nodes, forces can be extracted indirectly. This thesisdescribes considerations made during design of the system as well as its differentparts and configurations.
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Веселова, Надія Вікторівна. "Становлення і розвиток харківських наукових шкіл у галузі техніки та електрофізика високих напруг (1930–2010 рр.)". Thesis, НТУ "ХПІ", 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/17177.
Повний текст джерелаАнотація:
Дисертація на здобуття наукового ступеня кандидата історичних наук за спеціальністю 07.00.07 – історія науки і техніки. – Національний технічний університет "Харківський політехнічний інститут". – Харків, 2015. У дисертації комплексно досліджується створення та розвиток харківських наукових шкіл у галузі техніки та електрофізики високих напруг у 1930–2010 рр. В роботі визначені харківські наукові школи в цій галузі, а саме: наукова школа високовольтних прискорювачів в УФТІ, яку очолив академік АН УРСР А. К. Вальтер; наукова школа техніки високих напруг ХПІ, засновником якої став академік АН УРСР В. М. Хрущов; наукова школа магнітно-імпульсної обробки металів ХПІ, що була заснована проф. І. В. Білим. Проведено цілісний науково-історичний аналіз процесу виникнення технічних рішень в електрофізиці і створення установок високої напруги в провідних харківських наукових центрах. Розкрито процес формування складу наукових установ і лабораторій, внесок окремих вчених у розвиток техніки і електрофізики високих напруг в м. Харкові. Показана важливість та унікальність створених високовольтних установок, визначено передумови їх створення та досліджено застосування цих пристроїв у вітчизняній науці та промисловості.The thesis for the competition of the academic degree of the candidate of the historical sciences, the speciality 07.00.07 – The history of science and technique. – National Technical University "Kharkiv Polytechnic Institute". – Kharkiv, 2015. The thesis is devoted to the complex research of the establishment and the development of Kharkiv scientific schools in the field of the technique and the electrophysics of the high-voltages in 1930's – 2010's. In this work the Kharkiv scientific schools in this field were identified for the first time. They are: the scientific school of the high-voltage accelerators in the UFTI headed by academician of USSR A.K. Walter; the scientific school of the technique of high-voltages in the KhPI, the founder of which was the acacademician of the Academy of Sciences of USSR V. M. Khrushchev; the scientific school of magnetic-pulse treatment of metals in KhPI which was founded by professor I. V. Belii. A holistic scientific-historical analysis of the process of technical solutions in electrophysics and the creation of high-voltage installations in leading scientific centers of Kharkiv is carried out in this work. The importance and uniqueness of the high-voltage installations is shown here. The importance and the uniqueness of the high-voltage structures, the conditions of their creation usage in home industry and science are shown here.
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Веселова, Надія Вікторівна. "Становлення і розвиток харківських наукових шкіл у галузі техніки та електрофізика високих напруг (1930–2010 рр.)". Thesis, НТУ "ХПІ", 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/17176.
Повний текст джерелаАнотація:
Дисертація на здобуття наукового ступеня кандидата історичних наук за спеціальністю 07.00.07 – історія науки і техніки. – Національний технічний університет "Харківський політехнічний інститут". – Харків, 2015.
У дисертації комплексно досліджується створення та розвиток харківських наукових шкіл у галузі техніки та електрофізики високих напруг у 1930–2010 рр. В роботі визначені харківські наукові школи в цій галузі, а саме: наукова школа високовольтних прискорювачів в УФТІ, яку очолив академік АН УРСР А. К. Вальтер; наукова школа техніки високих напруг ХПІ, засновником якої став академік АН УРСР В. М. Хрущов; наукова школа магнітно-імпульсної обробки металів ХПІ, що була заснована проф. І. В. Білим. Проведено цілісний науково-історичний аналіз процесу виникнення технічних рішень в електрофізиці і створення установок високої напруги в провідних харківських наукових центрах. Розкрито процес формування складу наукових установ і лабораторій, внесок окремих вчених у розвиток техніки і електрофізики високих напруг в м. Харкові. Показана важливість та унікальність створених високовольтних установок, визначено передумови їх створення та досліджено застосування цих пристроїв у вітчизняній науці та промисловості.The thesis for the competition of the academic degree of the candidate of the historical sciences, the speciality 07.00.07 – The history of science and technique. – National Technical University "Kharkiv Polytechnic Institute". – Kharkiv, 2015. The thesis is devoted to the complex research of the establishment and the development of Kharkiv scientific schools in the field of the technique and the electrophysics of the high-voltages in 1930's – 2010's. In this work the Kharkiv scientific schools in this field were identified for the first time. They are: the scientific school of the high-voltage accelerators in the UFTI headed by academician of USSR A.K. Walter; the scientific school of the technique of high-voltages in the KhPI, the founder of which was the acacademician of the Academy of Sciences of USSR V. M. Khrushchev; the scientific school of magnetic-pulse treatment of metals in KhPI which was founded by professor I. V. Belii. A holistic scientific-historical analysis of the process of technical solutions in electrophysics and the creation of high-voltage installations in leading scientific centers of Kharkiv is carried out in this work. The importance and uniqueness of the high-voltage installations is shown here. The importance and the uniqueness of the high-voltage structures, the conditions of their creation usage in home industry and science are shown here.
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Chazottes-Leconte, Aurélien. "Conception et fabrication d'un dispositif de mise en compression par impulsions électro magnétiques (EMP)." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1082.
Повний текст джерелаАнотація:
Les procédés de traitement de surface sont utilisés à l'échelle industrielle pour améliorer les performances de pièces mécaniques en introduisant des contraintes résiduelles de compression. Cette mise en compression de surface permet de limiter l'amorçage et la propagation de fissures dans le matériau. Ceci permet d'augmenter de façon significative la durée de vie en fatigue des pièces mécaniques ainsi traitées. L'utilisation de ces procédés dans l'industrie a démontré leur efficacité, mais aussi leurs limitations et inconvénients. Les défauts récurrents consistent en une profondeur traitée faible, une dégradation de l'état de surface (rugosité), des difficultés de contrôle, une contamination du matériau traité, etc. Ces défauts ont conduit à l'élaboration de nouveaux procédés innovants qui permettent de meilleures performances en évitant certains des inconvénients succinctement évoqués. Parmi ces procédés innovants, le traitement de surface par impulsion électromagnétique semble particulièrement intéressant. Ce procédé met en œuvre un puissant champ magnétique transitoire pour engendrer des forces de Laplace dans une pièce métallique et induire des contraintes résiduelles. Il n'existe que peu d'informations dans la littérature et il n'existe aucun dispositif expérimental de ce procédé. Cette thèse est dédiée à la conception et la réalisation d'un prototype de mise en compression électromagnétique. Le premier chapitre de cette thèse est un état de l'art des technologies de mise en compression et du procédé de mise en compression par impulsion électromagnétique. Ainsi, les besoins de ce procédé sont identifiés et les technologies pouvant répondre à ces besoins sont explorées. Le deuxième chapitre, après une sélection de la structure globale du dispositif, va consister aux dimensionnements des éléments du prototype EMP. Cette étude commencera avec une étude sur l'inducteur qui va être utilisé avant de continuer sur le dimensionnement du stockage d'énergie et de l'interrupteur de décharge. Afin de valider le dimensionnement des composants précédents, une simulation électromagnétique 3D du système est réalisée. L'assemblage du prototype est présenté dans le troisième chapitre ainsi qu'une première campagne d'essai sur un alliage d'aluminium. Deux types d'éprouvettes sont testées : une éprouvette fine pour vérifier visuellement la mise en compression (essai Almen) et une éprouvette massive afin d'évaluer la profondeur traitée. Une modélisation multiphysique 3D du procédé est réalisée afin de corréler ces résultats avec l'expérience. Dans un dernier chapitre, une étude exploratoire est menée sur un matériau ferromagnétique, le mumétal, pour visualiser l'influence des contraintes résiduelles sur les propriétés magnétiques de ce dernierPenning processes are widely used in industries to apply compressive residual stresses into the most solicited part of mechanical pieces. In that way, the compressive residual stresses limit the priming and the propagation of micro-cracks in the material. This increases significantly the lifespan of the treated mechanical piece under fatigue stresses. These existing peening processes have proved their efficiency and also their limitations and weaknesses. The main recurrent defaults are a shallow depth of treatment, a degradation of the surface condition, a random control of the treatment, a material contamination, etc. These problems have led towards the development of news innovative peening processes which allow better performance avoiding some previous defaults briefly evoked. Among these news processes, the electromagnetic peening process seems especially interesting. This process uses high energy electromagnetic fields to induce Lorentz forces into a metallic piece and thus residual stresses. Actually, there is not much information about this process in the literature and no prototype was ever built. The work of this thesis is dedicated to development and realization of an electromagnetic peening prototype. The first chapter of this thesis adresses the state of the art of major peening processes actually in industrial use. Next, the electromagnetic peening process, or EMP process, is described and the electrical needs are exposed. A second state of the art is made about the technological solutions to respond to the EMP needs. The second chapter is about the conception of the EMP prototype with the electrical structure adopted in the previous chapter. The first step is about the inductor sizing to generate an electromagnetic field sufficient enough for a peening application. Next, the storage system is designed depending on the inductor parameters and finally the closing switch is created considering the electrical parameters used for the EMP process. To validate the previous results, a 3D electromagnetic simulation is done. The prototype assembly is presented in the third chapter and also the first experimental test on the EMP prototype. To begin with, an aluminium alloy with low yield strength is selected to be treated. Two different samples forms are used, a thin one, to realize a similar test to the Almen test and thick one to check the EMP depth of treatment. A 3D multiphysics simulation of these experiments is made and these numeric results are next correlated to the experimental ones. In the fourth chapter, an exploratory study is realized on the effects of the residual stresses on magnetic properties of ferromagnetic material, the mumetal
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Katic, Janko. "Highly-Efficient Energy Harvesting Interfaces for Implantable Biosensors." Doctoral thesis, KTH, Integrerade komponenter och kretsar, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-206588.
Повний текст джерелаАнотація:
Energy harvesting is identified as an alternative solution for powering implantable biosensors. It can potentially enable the development of self-powered implants if the harvested energy is properly handled. This development implies that batteries, which impose many limitations, are replaced by miniature harvesting devices. Customized interface circuits are necessary to correct for differences in the voltage and power levels provided by harvesting devices from one side, and required by biosensor circuits from another. This thesis investigates the available harvesting sources within the human body, proposes various methods and techniques for designing power-efficient interfaces, and presents two CMOS implementations of such interfaces. Based on the investigation of suitable sources, this thesis focuses on glucose biofuel cells and thermoelectric harvesters, which provide appropriate performance in terms of power density and lifetime. In order to maximize the efficiency of the power transfer, this thesis undertakes the following steps. First, it performs a detailed analysis of all potential losses within the converter. Second, in relation to the performed analysis, it proposes a design methodology that aims to minimize the sum of losses and the power consumption of the control circuit. Finally, it presents multiple design techniques to further improve the overall efficiency. The combination of the proposed methods and techniques are validated by two highly efficient energy harvesting interfaces. The first implementation, a thermoelectric energy harvesting interface, is based on a single-inductor dual-output boost converter. The measurement results show that it achieves a peak efficiency of 86.6% at 30 μW. The second implementation combines the energy from two sources, glucose biofuel cell and thermoelectric harvester, to accomplish reliable multi-source harvesting. The measurements show that it achieves a peak efficiency of 89.5% when the combined input power is 66 μW.Energiskörd har identifierats som en alternativ lösning för att driva inplanterbara biosensorer. Det kan potentiellt möjliggöra utveckling av själv-drivna inplanterbara biosensorer. Denna utveckling innebär att batterier, som sätter många begränsningar, ersätts av miniatyriserade energiskördsenheter. Anpassade gränssnittskretsar är nödvändiga för att korrigera för de skillnader i spänning och effektnivå som produceras av de energialstrande enheterna, och de som krävs av biosensorkretsarna. Denna avhandling undersöker de tillgängliga källorna för energiskörd i den mänskliga kroppen, föreslår olika metoder och tekniker för att utforma effektsnåla gränssnitt och presenterar två CMOS-implementeringar av sådana gränssnitt. Baserat på undersökningen av lämpliga energiskördskällor, fokuserar denna avhandling på glukosbiobränsleceller och termoelektriska energiskördare, som har lämpliga prestanda i termer av effektdensitet och livstid. För att maximera effektiviteten hos effektöverföringen innehåller denna avhandling följande steg. Först görs en detaljerad analys av alla potentiella förluster inom boost-omvandlare. Sedan föreslår denna avhandling en designmetodik som syftar till att maximera den totala effektiviteten och effektförbrukningen. Slutligen presenterar den flera designtekniker för att ytterligare förbättra den totala effektiviteten. Kombinationen av de föreslagna metoderna och teknikerna är varierade genom två högeffektiva lågeffekts energigränssnittskretsar. Den första inplementeringen är ett termoelektriskt energiskördsgränssnitt baserat på en induktor, med dubbla utgångsomvandlare. Mätresultaten visar att omvandlaren uppnår en maximal effektivitet av 86.6% vid 30 μW. Det andra genomförandet kombinerar energin från två källor, en glukosbiobränslecell och en termoskördare, för att åstadkomma en tillförlitlig multi-källas energiskördslösning. Mätresultaten visar att omvandlaren uppnår en maximal effektivitet av 89.5% när den kombinerade ineffekten är 66 μW.
QC 20170508
Mi-SoC
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Tse, Jonathan Michael. "High-Voltage Signal Generator for Biomedical Applications." Thesis, University of Canterbury. Electrical and Computer, 2011. http://hdl.handle.net/10092/7326.
Повний текст джерелаАнотація:
Electroporation is the process where externally applied electric fields cause significantly increased permeability of the cell membrane. The increased permeability allows the transport of external compounds into the cell. This is important for applications in electrochemotheropy, electrofusion and drug delivery.
Electroporation also has applications in the disinfection of liquids. Given a high enough electric field across the cell membrane, the electroporation process can become irreversible, leading to cell destruction. With the cell membrane under an intense electric field, the cell membrane structure fails causing the cell to die. Conventional liquid beverage disinfection systems rely on slow heating methods requiring large power
requirements; this can reduce the taste and quality of some liquids.
Pulse generators provide the necessary electric fields to produce the required voltage potential across the cell membrane. The usefulness of electroporation depends on
several parameters such as amplitude, frequency and rise/fall times of the electric field. The wave shape also has a bearing on performance, and is limited by the pulse generator
topology. A multilevel bipolar waveform is desired with operating frequencies above about 1 kHz. The cascaded H-bridge or full-bridge topology is the most useful as it capable of producing multilevel bipolar waveforms at high frequency.
This thesis presents the design and implementation of a multilevel high-voltage pulse generator, capable of creating very high-voltage AC pulses. MOSFET switching devices in conjunction with good layout practices were used to provide required fast switching speeds. The full-bridge topology is used to create a multilevel output profile through cascading of multiple stages. As a full-bridge topology inherently creates a
RCL resonant network, there are many challenges associated with mitigating high-frequency noise sources.
Two separate stages are built, a low voltage stage capable of outputting up to 200 Vp and a high voltage stage capable of switching up to 1 kVp. A control board was also built for pulse signal generation and user configuration of the output waveforms. The designed pulse generator can produce short pulses of up to 1.4 kVp at frequencies of up to 350 kHz using primarily resistive loads (that simulate a conductive liquid load).
Little high frequency switching noise was observable on the output waveform. A single stage pulse generator was also tested with actual liquid loads using an electrode chamber, demonstrating electroporation. The liquid load testing was performed on water and milk derived from milk powder. Results showed that the liquid loads were consistent with primarily resistive loads.
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FERREIRA, LUIS FERNANDO. "STATIC AND DYNAMIC SIMULATION FOR GENERATOR VOLTAGE CONTROL." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2006. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9454@1.
Повний текст джерелаАнотація:
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOO problema tratado nesta dissertação é a relação oposta entre a tensão de excitação de geradores e compensadores síncronos e a tensão controlada, quando o sistema de transmissão da área encontra-se muito carregado. Neste caso, a capacidade nominal de um gerador / compensador não seria útil para manter a tensão controlada. Devido à relação oposta, uma maior excitação da máquina iria abaixar a tensão controlada. O controle automático iria continuar agindo, abaixando ainda mais a tensão. Este mecanismo pode levar o sistema ao colapso e foi verificado em ponto de operação real do sistema brasileiro. Esse fenômeno ocorre quando a injeção de potência na rede de transmissão ou distribuição é elevada. Com o advento da geração distribuída, co-geração e produtores independentes, usualmente conectados à rede existente em níveis de tensão mais baixas, têm-se observado ocorrências do fenômeno. O objetivo do trabalho é então entender melhor as situações operativas reais que levam à ocorrência do fenômeno, principalmente quando existem vários equipamentos de controle de tensão ao redor do gerador em análise. A abordagem do problema baseou-se na verificação do comportamento do gerador / compensador como dispositivo de controle de tensão, no domínio do tempo e em regime permanente. Avaliaram-se as ações de controle do mesmo a partir de sete tipos de análise distintas para pontos de operação na região normal e anormal da curva SV. A real existência do fenômeno foi comprovada através de algumas destas análises. Porém, conclui-se que nem todas as formas de análise no domínio do tempo fazem uma avaliação completa do fenômeno. Dentre essas, estão a análise dinâmica agregada e a análise dinâmica agregada sob influência dos equipamentos de controle de tensão, que para pontos de operação na região anormal da curva SV não responderam em concordância com os outros tipos de análise.
The problem addressed in this research is the opposite relationship between the , synchronous generator / compensator excitation voltage and the controlled voltage when nearby network is heavily loaded. In this situation, the nominal capacity of a generator / compensator would not keep the voltage controlled. Due to the opposite relationship, the higher the excitation voltage the lower is the controlled voltage. So, the automatic control would continue acting lowering the voltage. This mechanism, verified in a real operational point of the Brazilian Electric System, can lead the system to collapse. This phenomenon occurs when the power injection into the network is high. It is prone to occur in the new scenario of distributed generation connected to already existing low voltage networks. The objective of this work is to understand the actual operative situations that lead to the occurrence of the phenomenon, mainly when there are several voltage control devices nearby the generator. The analysis of the problem was based on the verification of the generator behaviour as a voltage control device, in time domain simulation and in steady state. The control actions were evaluated from seven different ways for operating points in the normal and the abnormal region of the SV curve. The actual existence of the phenomenon was proven through some of these analyses. However, some of the time domain simulations did not evaluated the phenomenon completely. Among them, the aggregated dynamic analysis and the aggregated dynamic analysis under influence of other voltage control devices have not got the expected responses for the abnormal region of the SV curve, in comparison with other analysis.
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Tao, Lixi. "Adaptive High Voltage Pulse Signal Generator Circuit Design." ScholarWorks @ UVM, 2017. http://scholarworks.uvm.edu/graddis/782.
Повний текст джерелаАнотація:
Ground Penetrating Radar (GPR) is widely used in area of geologic exploration, hidden stationary subject detection and quality inspection on various infrastructures. The pulse generator, which offers very accurate timing information, is the most cardinal component in GPR systems. It is easy to design a pulse generator which produces pulse with pre-settled peak value and pulse width in nanosecond scale. However, since the system is working in complicated environments, various pulses in different pulse widths and amplitudes are needed. In this background, pulse generators in tunability and stability are precious in value and universal in use. Indeed, a few adaptive high voltage pulse signal generators in UWB circuit level have been developed.
A pulse generator with tunable pulse width and controllable voltage amplitude is proposed under these demands. The proposed circuit implementation combines System-On-Chip (SOC) design with Printed Circuit Board (PCB) design because we intend to realize modulation separately. We also design an easy input console named Binary Input Array in the research to realize control simplicity. Furthermore, we employ mathematical model to optimize parameters in each component in order to have an improved performance. Simulation data are obtained from Cadence Virtuoso and OrCAD Capture.
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Schwardt, Eckhard Detlef. "Development of a novel high-voltage arbitrary-waveform generator." Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/19863.
Повний текст джерелаАнотація:
Thesis (MSc)--University of Stellenbosch, 2007.ENGLISH ABSTRACT: The dielectric-barrier discharge (DBD) is a source of non-equilibrium plasma that has seen widespread industrial application in recent years. A high-voltage arbitrary-waveform generator has been designed, built and characterised for the purpose of investigating the influence that the applied voltage waveform has on the operation of a DBD. The developed arbitrary-waveform generator is based on the principle of Fourier synthesis. Up to twenty Fourier components are generated by means of a digital circuit board, and then separately amplified by Class-AB amplifiers. Twenty step-up transformers are subsequently used to transform the Fourier components to higher voltages; the summation of the Fourier components are realised by the series connection of the transformer secondary sides. It was found that the digital generation of the Fourier components is very accurate and provides for the easy configuration of arbitrary waveforms. Furthermore, the amplification of the Fourier components by the Class-AB amplifiers introduces very little distortion. The principle of adding the Fourier components via the step-up transformers has been demonstrated; however, the large distributed capacitances of the transformers adversely affect the operation of the Class-AB amplifiers, leading to the introduction of distortion into the generated waveform. Furthermore, it was found that care had to be taken to limit the introduction of EMI through the system’s large ground plane.
AFRIKAANSE OPSOMMING: Die di¨elektriese versperringsontlading (DVO) is ’n bron van nie-ekwilibrium plasma wat in die afgelope jare wye toepassing in die nywerheid gevind het. ’n Arbitrˆere-golfvorm hoogspanningskragbron is ontwerp, gebou en gekarakteriseer, met die doel om die invloed wat die aangewende spanningsgolfvorm het op die werking van die DVO, te ondersoek. Die ontwikkelde arbitrˆere golfvormgenerator is gebaseer op die beginsels van Fourier samestelling. Tot twintig Fourier komponente word digitaal gegenereer, en dan afsonderlik versterk deur Klas-AB versterkers. Twintig transformators word dan gebruik om die Fourier komponente na ho¨er spannings te transformeer. Die sommasie van die Fourier komponente geskied deur die serieskakeling van die transformators se sekondˆere windings. Daar is bevind dat die digitale generasie van die Fourier komponente baie akkuraat is, en dat die arbitrˆere golfvorms maklik verstel kan word. Verder versterk die Klas-AB versterkers die Fourier komponente sonder enige noemenswaardige vervorming. Die gebruik van die transformators om die Fourier komponente saam te voeg, is gedemonstreer. Die groot verspreide kapasitansies van die transformators be¨ınvloed egter die funksioneering van die Klas-AB versterkers, wat lei tot ’n vervorming van die uittree. Daar is ook bevind dat die toetrede van EM versteurings deur die grondvlak van die sisteem problematies kan wees.
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Zhang, ZiHao. "A High Temperature Reference Voltage Generator with SiC Transistors." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/72888.
Повний текст джерелаАнотація:
Natural resources are always collected from harsh environments, such as mines and deep wells. Currently, depleted oil wells force the gas and oil industry to drill deeper. As the industry drills deeper, temperatures of these wells can exceed 210 °C. Contemporary downhole systems have reached their depth and temperature limitations in deep basins and are no longer meet the high requirements in harsh environment industries. Therefore, robust electronic systems that can operate reliably in harsh environments are in high demand. This thesis presents a high temperature reference voltage generator that can operate reliably up to 250 °C for a downhole communication system. The proposed reference voltage generator is designed and prototyped using 4H-SiC bipolar transistors. Silicon carbide (SiC) is a semiconductor material that exhibits wide bandgap, high dielectric breakdown field strength, and high thermal conductivity. Due to these properties, it is suitable for high-frequency, high-power, and high-temperature applications. For bypassing the lack of high temperature p-type SiC transistors (pnp BJT, PMOS) and OpAmp inconvenience, an all npn voltage reference architecture has been developed based on Widlar bandgap reference concept. The proposed reference voltage generator demonstrates for the first time a functional high temperature discrete reference voltage generator that uses only five 4H-SiC transistors to achieve both temperature and supply independent. Measurement results show that the proposed voltage reference generator provides an almost constant negative reference voltage around -3.23 V from 25 °C to 250 °C regardless of any change in power supply with a low temperature coefficient (TC) of 42 ppm/°C.Master of Science
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Mutsuura, Keita, Hirotaka Shimizu, Yasunobu Yokomizu, and Toshiro Matsumura. "Flux flow resistance in Bi2223 generated by pulse currents." IEEE, 2005. http://hdl.handle.net/2237/6789.
Повний текст джерела
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Smith, Nigel P. A. "Self-excited micro-hydro generator with voltage and frequency control." Thesis, Nottingham Trent University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314633.
Повний текст джерела
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Bethi, Shiva Sai. "A Temperature and Process Insensitive CMOS Only Reference Current Generator." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1416406367.
Повний текст джерела
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Caliskan, Ahmet. "Constant Voltage, Constant Frequency Operation Of A Self-excited Induction Generator." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606678/index.pdf.
Повний текст джерелаАнотація:
In this thesis, control schemes for the self-excited induction generator are developed with Matlab/Simulink. Self-excited induction generator is considered as a constant voltage-constant frequency supply for an isolated load. A wind turbine is assumed to be the variable-speed drive of the induction generator. Control schemes aim to ensure a constant voltage-constant frequency operation of the induction generator in case of the variations in the wind speed and/or the load.
From the general model of the self-excited induction generator, the characteristics of the system and the dynamic responses of the system in case of any disturbance are
examined. Next, the control strategies are developed both for the squirrel-cage rotor induction generator and for the wound-rotor induction generator. Two control loops are necessary for constant voltage-constant frequency operation of a variable speed induction generator, one for the voltage regulation and the other for the frequency regulation. After developing the control loops, constant voltage-constant frequency
operation of the self-excited induction generator is simulated with a cage type saturation adaptive induction generator, a fixed capacitor with thyristor controlled reactor (TCR) used for frequency regulation and switched external resistors
connected to the stator terminals used for voltage regulation.
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Dragonas, Filopimin Andreas <1983>. "Arbitrary Waveform Multilevel Generator for High Voltage High Frequency Plasma Actuators." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6249/.
Повний текст джерелаАнотація:
This dissertation presents the theory and the conducted activity that lead to the construction of a high voltage
high frequency arbitrary waveform voltage generator. The
generator has been specifically designed to supply power to a wide range of plasma actuators. The system has been completely designed, manufactured and tested at the Department of Electrical, Electronic and Information Engineering of the University of Bologna. The generator structure is based on the single phase cascaded H-bridge multilevel topology and is comprised of 24 elementary units that are series connected in order to form the typical staircase output voltage waveform of a multilevel converter. The total number of voltage levels that can be produced by the generator is 49. Each level is 600 V making the output peak-to-peak voltage equal to 28.8 kV. The large number
of levels provides high resolution with respect to the output voltage having thus the possibility to generate arbitrary waveforms. Maximum frequency of operation is 20 kHz. A study of the relevant literature shows that this is the first time that a cascaded multilevel converter of such
dimensions has been constructed. Isolation and control
challenges had to be solved for the realization of the system. The biggest problem of the current technology in
power supplies for plasma actuators is load matching. Resonant converters are the most used power supplies and are seriously affected by this problem. The manufactured generator completely solves this issue providing consistent voltage output independently of the connected load. This fact is very important when executing tests and during the comparison of the results because all measures should be comparable and not dependent from matching issues.
The use of the multilevel converter for power supplying a plasma actuator is a real technological breakthrough
that has provided and will continue to provide very significant experimental results.
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Bladh, Johan. "Hydropower generator and power system interaction." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-182188.
Повний текст джерелаАнотація:
After decades of routine operation, the hydropower industry faces new challenges. Large-scale integration of other renewable sources of generation in the power system accentuates the role of hydropower as a regulating resource. At the same time, an extensive reinvestment programme has commenced where many old components and apparatus are being refurbished or replaced. Introduction of new technical solutions in existing power plants requires good systems knowledge and careful consideration. Important tools for research, development and analysis are suitable mathematical models, numerical simulation methods and laboratory equipment. This doctoral thesis is devoted to studies of the electromechanical interaction between hydropower units and the power system. The work encompasses development of mathematical models, empirical methods for system identification, as well as numerical and experimental studies of hydropower generator and power system interaction. Two generator modelling approaches are explored: one based on electromagnetic field theory and the finite element method, and one based on equivalent electric circuits. The finite element model is adapted for single-machine infinite-bus simulations by the addition of a network equivalent, a mechanical equation and a voltage regulator. Transient simulations using both finite element and equivalent circuit models indicate that the finite element model typically overestimates the synchronising and damping properties of the machine. Identification of model parameters is performed both numerically and experimentally. A complete set of equivalent circuit parameters is identified through finite element simulation of standard empirical test methods. Another machine model is identified experimentally through frequency response analysis. An extension to the well-known standstill frequency response (SSFR) test is explored, which involves measurement and analysis of damper winding quantities. The test is found to produce models that are suitable for transient power system analysis. Both experimental and numerical studies show that low resistance of the damper winding interpole connections are vital to achieve high attenuation of rotor angle oscillations. Hydropower generator and power system interaction is also studied experimentally during a full-scale startup test of the Nordic power system, where multiple synchronised data acquisition devices are used for measurement of both electrical and mechanical quantities. Observation of a subsynchronous power oscillation leads to an investigation of the torsional stability of hydropower units. In accordance with previous studies, hydropower units are found to be mechanically resilient to subsynchronous power oscillations. However, like any other generating unit, they are dependent on sufficient electrical and mechanical damping. Two experimentally obtained hydraulic damping coefficients for a large Francis turbine runner are presented in the thesis.
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López, Julià Toni. "Prospects of voltage regulators for next generation computer microprocessors." Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/77908.
Повний текст джерелаАнотація:
Synchronous buck converter based multiphase architectures are evaluated to
determine whether or not the most widespread voltage regulator topology can
meet the power delivery requirements of next generation computer
microprocessors. According to the prognostications, the load current will rise to
200A along with the decrease of the supply voltage to 0.5V and staggering tight
dynamic and static load line tolerances. In view of these demands, researchers face
serious challenges to bring forth compliant solutions that can further offer
acceptable conversion efficiencies and minimum mainboard area occupancy.
Among the most prominent investigation fronts are those surveying
fundamental technology improvements aiming at making power semiconductor
devices more effective at high switching frequency. The latter is of critical
importance as the increase of the switching frequency is fundamentally recognized
as the way forward to enhance power density conversion. Provided that switching
losses must be kept low to enable the miniaturization of the filter components, one
primary goal is to cope with semiconductor and system integration technologies
enabling fast dynamic operation of ultra-low ON resistance power switches.
This justifies the main focus of this thesis work, centered around a
comprehensive analysis of the MOSFET switching behavior in the synchronous
buck converter.
The MOSFETs dynamic operation, far from being well describable with the
traditional clamped inductive hard-switching mode, is strongly influenced by a
number of frequently ignored linear and nonlinear parasitic elements that must be
taken into account in order to fully predict real switching waveforms, understand
their dynamics, and most importantly, identify and quantify the related
mechanisms leading to heat generation. This will be revealed from in-depth
investigations of the switched converter under fast switching speeds and heavy
load.
Recognizing the key relevance of appropriate modeling tools that support this
task, the second focal point of the thesis aims at developing a number of suitable
models for the switching analysis of power MOSFETs.
Combined with a series of design guidelines and optimization procedures, these
models form the basis of a proposed methodological approach, where numerical
computations replace the usually enormous experimental effort to elucidate the
most effective pathways towards reducing power losses. This gives rise to the
concept referred to as virtual design loop, which is successfully applied to the
development of a new power MOSFET technology offering outstanding dynamic
and static performance characteristics. From a system perspective, the limits of the
power density conversion will be explored for this and other emerging
technologies that promise to open up a new paradigm in power integration
capabilities.
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LEITE, ARMANDO GONCALVES. "STATIC AND DYNAMIC SIMULATION OF VOLTAGE CONTROL BY GENERATOR AND SYNCHRONOUS COMPENSATOR." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2008. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=12362@1.
Повний текст джерелаАнотація:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROO tema abordado neste trabalho é a observação e análise, em regime permanente e dinâmico, da ocorrência de um fenômeno que já foi observado em condições reais de operação do sistema elétrico brasileiro, que é a relação oposta entre a tensão de excitação de geradores e compensadores síncronos e a tensão controlada. Nessas situações, a capacidade nominal de um gerador / compensador síncrono, por exemplo, não seria útil para manter a tensão controlada. Em virtude da relação oposta, um aumento na excitação da máquina abaixaria a tensão controlada. O controle automático continuaria agindo, abaixando ainda mais a tensão. Este mecanismo pode levar o sistema ao colapso. A abordagem do problema baseou-se na verificação do comportamento do gerador / compensador como dispositivo de controle de tensão, em regime permanente e dinâmico, ante as diversas situações normais de um sistema elétrico, tais como variações do valor da tensão de referência (tensão controlada) e de carga. A análise em regime permanente utilizou um algoritmo de fluxo de carga, enquanto a análise em regime dinâmico utilizou a simulação no domínio do tempo. A real existência do fenômeno foi comprovada através de várias destas análises, mostrando inclusive a mudança da região de operação em algumas delas. Em outros casos, os resultados da análise em regime permanente não coincidiram com os da análise em regime dinâmico.
The aim of this work is to investigate, in steady state and dynamic performance, the phenomenon of the opposite relationship, already observed at real operation conditions of the Brazilian Electric System, between generators and synchronous compensators excitation voltage and the controlled one. In these situations, the generator / synchronous compensator nominal capacity, for example, would not be useful to keep the voltage controlled. Due the opposite relationship, an increase in the excitation voltage would reduce the controlled voltage. The automatic control would keep acting and reducing more the voltage. This mechanism can lead the system to the collapse. The study of this problem was based in the generator / compensator behavior as a control voltage device, in steady- state and dynamic performance, front of several operation situations of electric power system, like reference voltage (controlled voltage) variation and load changing. The steady state analysis used a load flow algorithm, while the time domain simulation was utilized for the dynamic performance analysis. The real existence of the phenomenon was verified through these analyses, emphasizing the operation region changing in some of them. In other cases, the analyses results in the steady-state were different of the dynamic performance results.
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Miao, Dongmin. "Voltage Stabilization Control of Wide-Speed-Range Permanent-Magnet Synchronous Generator Systems." Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/246410.
Повний текст джерелаАнотація:
DC power systems have a constant DC-link voltage, as well as the advantages such as high stability, high efficiency, small size and light weight; therefore, they are widely used in stand-alone power systems, e.g. the power systems in aircrafts and automobiles, isolated wind power generation systems, etc. Permanent-Magnet Synchronous Generators (PMSGs) possess the advantages including high power density, high efficiency, and high control precision, and have obtained great attention and have been widely used in military, inductry, and daily life. Pulse Width Modulation (PWM) rectifier has been one of the main power conversion topologies thanks to its full controllability. The key point in the dissertation is to study the DC power system consisting of a PMSG to be the main power input device and a PWM rectifier to be the main power conversion topology. The objective of control is to output a constant DC-link voltage in a wide PMSG speed range. Since the PM-excited flux linkage is constant, when the PMSG is working at a high speed, field-weakening is needed to stabilize the stator voltage, further to stabilize the DC-link voltage. Hybrid excitation may be used to realize the field-weakening, but it has complex structure; no auxiliary devices are needed in the field regulation with the armature current, and can be easily realized with the PWM recifier and field-regulation control strategies. In this dissertation, the typical applications of the DC power systems are first introduced, with a comprehensive analysis and elaboration on the relevant research throughout the world. The research work is focused on the DC power system and its stabilization control, which is composed of a PMSG and a PWM rectifier. The involved research content in this dissertation includes the following aspects: 1. DC power system design with a wide-speed-range PMSGAs for the common DC power systems, PMSG with high power density, high efficiency is selected to the system power input device, usually with a variable-speed prime mover. The PWM rectifier with fully controlled switches is chosen to be the power conversion topology, which converts the AC power generated by PMSG into DC power, and supplies the DC load after the DC filter. The matching between the system requirements and the generator parameters are determined. Through finite-element analysis (FEA), a PMSG with strong field-weakening ability and suitable for wide-speed-range operation has been designed and manufactured, and the system test bench has been built based on dSPACE. 2. Study, analysis, optimization and experimental verification of the traditional control strategiesAccording to the PMSG designed in part 1, the DC-link model has been built, as well as the control model of the traditional control strategies, e.g. field-oriented control (FOC), direct torque control (DTC), and the effectiveness of the DC-link voltage stabilization control has been verified in a wide speed range. The theory of active damping has been proposed and analyzed, and has been utilized in the DC-link voltage control. When the load on the DC-link changes, the dynamic response of the DC-link voltage has been greatly accelerated, and it recovers quickly to its reference value. In the meantime, the performance influence of the prime mover speed on the actual system test bench should be considered. Finally, the performance of FOC and DTC has been compared and analyzed. 3. Analysis and experimental verification of the direct voltage control (DVC), and the comparative study of all the studied control strategiesThe derivation process of DVC has been theoretically analyzed: the inner current loops in FOC have been eliminated to obtain the direct voltage field-oriented control (DVFOC); the reference value of d-axis voltage in DVFOC has been replaced by the product of the stator voltage calculated by the speed and the load condition, and the sine value of load angle generated by the DC-link voltage PI controller, in order to form the DVC-1. Further, the DC-link voltage PI controller directly outputs the reference value of load angle and it becomes DVC-2. Finally, the comparative study has been carried out among all the studied control strategies.Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
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Ibrahim, Rania Assem Elsayed. "Low voltage ride-through of permanent magnet synchronous generator wind energy systems." Thesis, University of Strathclyde, 2014. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24907.
Повний текст джерелаАнотація:
Low Voltage Ride-Through (LVRT) capability is considered a critical feature that should be implemented within a Wind Energy Conversion System (WECS). The mismatch produced between the generated active power and the power delivered to the grid during any dip incidence at the Point of Common Coupling causes a dc link voltage rise, and increase in grid currents and generator speed-up. Failure to ride-through grid voltage dips would lead to converter failures within the WECS. This thesis focuses on enhancing LVRT capability of PMSG based WECS using magnetic amplifiers. LVRT techniques vary according to the turbine and utility grid variables. A survey of the state-of-art LVRT techniques highlighting the merits and demerits of each approach is carried out. A 1.5 MW wind turbine system is modelled, which includes the wind turbine, PMSG, and power converters. Also PMSG control, maximum power point extraction, and grid active and reactive power control are investigated. System performance is studied in compliance with British grid codes for active and reactive power sudden changes, frequency excursion, and grid voltage phase angle jump. The model is tested for LVRT capability under symmetrical network dips. Magnetic amplifiers have been used in various applications such as instrumentation, fault current limiting, and battery chargers. In this thesis, magnetic amplifiers are proposed as part of a LVRT capability enhancing technique. Two possible configurations are proposed; 3-phase and dc-side configurations. LVRT capability enhancement is investigated for the 1.5MW WECS using the two magnetic amplifier configurations. The 3-phase topology is able to reduce the dc link voltage rise; however, it causes an increase in the stored rotor inertia accompanied by an increase in generator speed. The dc-side magnetic amplifier topology is able to limit the dc-link voltage rise which in turn protects the power converters without affecting generator performance. In addition to simulations, a scaled prototype with the dc side magnetic amplifier configuration is used to verify the effectiveness and applicability of the proposed technique during steady state and transient behaviour under various operating conditions.
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Kucheruk, V. Yu, V. M. Sevastyanov, V. S. Mankovska, В. Ю. Кучерук, В. М. Севастьянов, and В. С. Манковська. "Resistance-to-voltage converter based on RL-diode generator of chaotic oscillations." Thesis, Одеський національний політехнічний університет, 2013. http://ir.lib.vntu.edu.ua/handle/123456789/2724.
Повний текст джерелаАнотація:
Resistance-to-voltage converter based on RL-diode generator of chaotic oscillations can be used for measurements (in the appliances for measuring non-electric physical quantities with the use resistive transducers).
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Kiuru, Wille. "Synchronous generator rotor position estimation from stator and rotor terminal currents and voltages." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194196.
Повний текст джерелаАнотація:
This thesis presents an alternative method for measuring the rotor position of a synchronousgenerator, without the use of sensors to measure the rotor position. The method uses thecurrent and voltage measurements on the stator and rotor terminals from the protectionrelays. The rst step is to investigate how the rotor position can be estimated basedon the available measurement data. It was found out that the rotor position couldn'tbe estimated during dynamic state operation, when directly solving it from measurementdata. This is due to the presence of the eld and d-axis damper winding current dynamics,including the q-axis damper winding current. In order to achieve this, multiple stepsconsisting of dierent methods for estimating the rotor position were utilized. The rststep is to estimate the rotor position during steady state. The second step estimates therotor position iteratively based on initial values. This method is useful during a dynamicstate operation. The initial values are obtained from the rst step at the start of a dynamicstate operation. The nal step predicts the rotor position based on previous data. It isused during cases when the second step fails to estimate the rotor position accurately.Due to insucient data for estimating the rotor position during saturation, the eects ofsaturation for the simulated synchronous machine were not considered.Detta projekt presenterar en alternativ metod för estimering av rotorvinkeln för en synkronmaskin med utpräglade poler, utan användning av sensorer. Metoden som används är att estimera rotorvinkeln genom uppmätt data av strömmar och spänningar från stator och rotor terminaler inom skyddsreläer. Första steget är att undersöka ifall rotorvinkeln kan bestämmas direkt ur mätdata. Det visade sig att rotorvinkeln kunde inte estimeras vid en dynamisk fas, genom att lösa rotorvinkeln direkt från mätdata. Detta på grund av strömmderivatan i fält och dämplindningen i d-led, samt strömmen i dämplindningen i q-led. För att uppnå detta, flera olika steg baserad på olika metoder användes för att estimera rotorvinkeln. Det första steget går ut på att estimera rotorvinkeln i ett stabilt läge. Det andra steget estimerar rotorvinkeln iterativt baserad på initialvärden. Denna metod är användbar vid ett icke-stabilt läge. Initialvärdena erhålls från steg ett vid början av ett icke-stabilt läge. Det slutliga steget förutsäger rotorvinkeln baserad på tidigare data. Den används då steg två misslyckas att estimera rotorvinkeln noggrant. På grund av otillräcklig data för att estimera rotorvinkeln under mättnad så togs inte mättnadsfenomen till hänsyn för den simulerade synkronmaskinen.
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Shokrollah-Timorabadi, Hamid. "Voltage source inverter for voltage and frequency control of a stand-alone self-excited induction generator." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0009/MQ34139.pdf.
Повний текст джерела
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Girardon, Hugo. "Shape reconstruction of deposits inside a steam generator using eddy current measurements." Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX086.
Повний текст джерелаАнотація:
Le contrôle non destructif est un outil essentiel pour évaluer la sûreté des infrastructures dans les centrales nucléaires. En particulier, la présence de dépôts conducteurs dans les tubes en U des générateurs de vapeur constitue un enjeu de la sûreté en bloquant le circuit d'eau secondaire. Pour détecter ces dépôts, des sondes à courants de Foucault sont insérées dans les tubes en U pour générer des courants et mesurer en retour un signal d'impédance. Pour inverser ces mesures et reconstruire la forme du dépôt, nous développons une méthode d'optimisation de forme avec descente de gradient régularisée. Du fait du caractère inconnu et possiblement complexe de la géométrie et de la topologie du dépôt, nous nous proposons de le modéliser par le biais d'une fonction level-set. La méthodologie est validée dans un premier temps sur des configurations axisymétriques artificielles et une rapide convergence est assurée par un choix réfléchi des paramètres de régularisation ainsi qu'une adaptation fine des pas de descente. En nous appuyant sur la configuration réelle dans laquelle sont réalisées les mesures expérimentales, nous considérons ensuite une modélisation plus réaliste incorporant la plaque entretoise ainsi que la présence d'imperfections sur la paroi intérieure du tube. Plus précisément, nous utilisons un modèle asymptotique pour prendre en compte ces imperfections et nous les traitons comme de nouvelles inconnues dans notre problème inverse. Une stratégie d'optimisation multi-critères se basant sur l'utilisation de différentes fréquences est ensuite développée pour résoudre le problème. Nous présentons différents résultats numériques sur des tests artificiels ou réels pour montrer la validité de note approche. Nous nous focalisons ensuite sur la transposition du modèle 2D-axisymétrique à des configurations 3D plus génériques. La résolution des équations de Maxwell en présence de courants de Foucault en 3D pose plusieurs problèmes de modélisation de part le choix de la formulation du problème ainsi que des coûts de calculs conséquents à réduire avant de pouvoir élaborer l'algorithme de reconstruction. Avec l'expérience acquise dans la reconstruction en 2D-axisymétrique, nous proposons ensuite une stratégie d'inversion efficace que nous mettons en œuvre sur des données artificielles 3D. La validation des exemples numériques prouve ainsi la faisabilité de l'inversion pour des problèmes de taille conséquente pour des coûts modérés et avec une bonne précision et robustesse par rapport au bruit et aux erreurs de modélisationNon-destructive testing is an essential tool to assess the safety of the facilities within nuclear power plants. In particular, conductive deposits on U-tubes in steam generators constitute a safety issue as they may block the cooling loop. To detect these deposits, eddy-current probes are introduced inside the U-tubes to generate currents and measuring back an impedance signal. We develop a shape optimization technique with regularized gradient descent to invert these measurements and recover the deposit shape. To deal with the unknown geometry, and its possibly complex topological nature, we propose to model it using a level set function.The methodology is first validated on synthetic axisymmetric configurations and fast convergence is ensured by careful adaptation of the gradient steps and regularization parameters. Using the actual domain, from which the acquisitions are made, we then consider a more realistic modeling that incorporates the support plate and the presence of imperfections on the tube interior section. We employ in particular an asymptotic model to take into account these imperfections and treat them as additional unknowns in our inverse problem. A multi-objective optimization strategy, based on the use of different operating frequencies, is then developed to solve this problem. We present various numerical examples with synthetic and experimental data showing the viability of our approach.The focus is then placed on the transposition of the 2D-axisymmetric work to more generic 3D configurations. Solving Maxwell eddy-current equations in 3D raises modeling issues related to the choice of the problem formulation as well as high computational costs that need to be reduced before discussing the reconstruction algorithm. Using the knowledge acquired with 2D-axisymmetric reconstruction, an efficient inversion strategy is then proposed and implemented on 3D synthetic data. Validating numerical examples demonstrate the feasibility of the inversion even for large data at a relatively moderate cost and with good accuracy and robustness with respect to noise and modeling errors
30
Aintablian, Hrair. "External characteristics and voltage regulation of a 3-phase induction generator under load." Ohio : Ohio University, 1989. http://www.ohiolink.edu/etd/view.cgi?ohiou1182275061.
Повний текст джерела
31
Muhr, Eloi. "Conception de générateurs d'impulsions et des circuits de mise en forme reconfigurables associés." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4346.
Повний текст джерелаАнотація:
Depuis 2002, différentes bandes de fréquences de plusieurs GHz dites « Ultra-Large Bande » (ULB), généralement comprises entre 3,1GHz et 10,6GHz, ont été libérées de par le monde pour la transmission d’informations sans fil. La largeur de ces bandes est telle qu’il devient envisageable d’utiliser des impulsions comme support de l’information en lieu et place d’une porteuse modulée comme cela est le cas habituellement. En effet, le spectre d’une impulsion étant inversement proportionnel à sa durée, une large plage de fréquences est requise pour la transmission d’informations via des impulsions. Cependant, il devient possible d’accroitre les débits en rapprochant les impulsions émises lorsque ceci est nécessaire, tout en offrant la possibilité d’éteindre les circuits et donc réduire la consommation lorsque deux impulsions sont suffisamment éloignées dans le temps.Le travail de recherche de cette thèse est dans ce contexte de proposer une structure d’émetteur impulsionnel reconfigurable disposant d’un contrôle suffisamment fin pour s’adapter aux différents canaux des standards IEEE 802.15.4 et 802.15.6 et ce, en n’utilisant que des circuits numériques pour les besoins des applications faibles coût. Pour cela, une étude théorique sur la mise en forme des impulsions requises est faite. Puis, il est question de la conception des différentes fonctions nécessaires à la mise en œuvre d’un émetteur impulsionnel reconfigurable, telles qu’un oscillateur contrôlé en tension pour la bande 3,1GHz-10,6GHz à démarrage rapide et que le circuit de mise en forme des oscillations associéSince 2002, various frequency bands of several GHz called "Ultra-WideBand" (UWB), generally between 3,1GHz and 10,6GHz, were liberalized in the world for wireless data transmission. The width of these bands is that it becomes possible to use pulses instead of a modulated carrier to transmit data. Indeed, as the spectrum of a pulse is inversely proportional to its duration, a wide range of frequencies is required for the transmission of information via pulses. However, it becomes possible to increase the rates by moving closer the emitted pulses when this is necessary, while providing the ability to switch off the circuits and thus reduce power consumption when two pulses are sufficiently far in time.To standardize the use of UWB frequency bands, standards such as IEEE 802.15.4 and 802.15.6 standards have emerged and have chosen to cut these frequency bands in channels of 500MHz and more. The aim of this thesis is also to propose a reconfigurable pulse transmitter structure with a fine enough control to address the different channels of IEEE 802.15.4 and 802.15.6 standard and, using only digital circuits to target low cost applications. For this, a theoretical study on the shaping of pulses required is made. Then it comes to the design of the various functions necessary for the implementation of a reconfigurable pulse transmitter, such as the implementation of a voltage controlled oscillator for 3,1GHz band-10,6GHz with quick start ability and the required oscillations shaping circuit
32
Un, Emre. "Common Mode Voltage And Current Reduction In Voltage Source Inverter Driven Three Phase Ac Motors." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609062/index.pdf.
Повний текст джерелаАнотація:
In this thesis various reduced common mode voltage (RCMV) pulse width modulation (PWM) techniques and active/passive common mode voltage (CMV) reduction methods for voltage source inverter driven three-phase AC motors are theoretically and practically investigated. A novel RCMV-PWM method, the near state PWM (NSPWM) method is proposed for operation at high modulation index. At low modulation index, a modified version of an existing RCMV-PWM method, AZSPWM1, termed as MAZSPWM, is proposed to mitigate the voltage reflection problem of the method. An optimum modulation algorithm combining NSPWM and MAZSPWM with seamless transition is proposed. The proposed RCMV-PWM methods significantly reduce CMV but they suppress common mode current (CMC) partially. Utilization of a common mode inductor together with RCMV-PWM methods is effective in suppressing the CMC. In the study, in addition to the CMV characteristics, various practical performance characteristics such as voltage linearity, inverter output current ripple, inverter DC-link current ripple, and output line-to-line voltage pulse pattern are also analyzed. The study involves analysis, computer simulations, and detailed laboratory experiments.
33
Santos, Kristian Pessoa dos. "Voltage impulse generator using a cascaded boost converter for the inspection of grounding systems." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13994.
Повний текст джерелаАнотація:
AssociaÃÃo TÃcnico-CientÃfica Eng. Paulo de FrontinThis paper presents the study and development of a voltage impulse generator using a cascaded boost converter topology operating in Discontinuous Conduction Mode (DCM) which will be used for the inspection of grounding systems used by electric power companies. The output voltage of the converter is applied to the grounding system which behaves as a load. The signal applied to the ground was measured by the data acquisition system and analyzed by an intelligent algorithms software. The voltage has the characteristics of a double exponential waveform which is a mathematical model used for study of lightning. Furthermore, the impulse generator has the option to produce a square waveform output voltage. Unlike, the traditional impulse generator with spark gaps, which was disadvantages of poor lifetime and the need of external system to operating the same, the developed generator uses only semiconductor devices in its construction. A theoretical study was carried out through qualitative and quantitative analyzes moreover, the switching process and the losses in the converter components were studied. In this work was performed the design of a cascaded boost converter for evaluating grounding systems with approximated 156 W, input voltage of 110 Vac rms and an output peak voltage of approximately 880 VDC, which correspond to the sum each voltage capacitor of the boost converter, when they are connected in series. A prototype with the indicated specifications was implemented and experimentally tested in the laboratory and real conditions using four grounding systems configurations. Tests were performed considering that the grounding impedance is resistive. The obtained experimental and simulation results are used to validate the theoretical analysis and the designed converter.
Este trabalho apresenta o estudo e desenvolvimento de um gerador de impulsos de tensÃo usando a topologia de um conversor boost em cascata operando em Modo de ConduÃÃo DescontÃnua (MCD) que serà utilizado para inspeÃÃo de sistemas de aterramentos usados pelas concessionÃrias de energia elÃtrica. A tensÃo obtida na saÃda do conversor à aplicada ao sistema de aterramento que se comporta como uma carga. O sinal aplicado ao aterramento à medido pelo sistema de aquisiÃÃo de dados e analisado pelo software por algoritmos inteligentes. A tensÃo aplicada tem as caracterÃsticas de uma onda tipo dupla exponencial que à um modelo matemÃtico para estudo de descargas atmosfÃricas. AlÃm disso, o gerador poderà gerar tensÃes com caracterÃsticas de uma onda quadrada. O gerador de impulsos desenvolvido utiliza apenas dispositivos semicondutores na sua construÃÃo que apresentam as vantagens de possuir uma longa vida Ãtil, podem operar em altas frequÃncias, sÃo acionados com baixa tensÃo e possuem uma baixa queda de tensÃo ao contrÃrio dos tradicionais geradores de impulsos que utilizam os spark gaps para chaveamento que apresentam como desvantagens a baixa vida Ãtil e a necessidade de um sistema externo para funcionamento da mesma. Um estudo teÃrico foi realizado atravÃs das anÃlises qualitativa e quantitativa, alÃm das anÃlises do processo de comutaÃÃo e das perdas nos componentes do conversor. Neste trabalho foi realizado o projeto do conversor boost em cascata para inspeÃÃo de sistemas de aterramento com uma potÃncia aproximada de 156 W, tensÃo de entrada eficaz de 110 Vca e tensÃo de pico de aproximadamente 880 Vcc que corresponde à soma da tensÃo dos capacitores do conversor boost quando estÃo dispostos em sÃrie. Um protÃtipo com as especificaÃÃes indicadas foi construÃdo e testado experimentalmente em laboratÃrio e em campo utilizando quatro topologias de sistemas de aterramento. Foram realizados testes considerando que a impedÃncia de aterramento era puramente resistiva. Os resultados de simulaÃÃo e experimentais obtidos sÃo utilizados para validar a anÃlise teÃrica e o projeto realizado.
34
Hoffe, Simon John. "Synchronous generator fault diagnosis using shaft signal measurements." Thesis, 2007. http://hdl.handle.net/10539/2124.
Повний текст джерелаАнотація:
Student Number :0008015M -
MSc Dissertation -
School of Electrical and Information Engineering -
Faculty of Engineering and the Built EnvironmentShaft voltages and currents are an unavoidable characteristic of rotating machines, though they are typically a nuisance this work shows that shaft signals can be used for fault diagnosis. This work focussed on shaft voltages present on synchronous generators. Measurements on a 4-pole generator found that the angular position of the shaft could be determined from the shaft voltage. An experimental 20 kVA 2-pole synchronous generator was designed and built which resembled a full-size 600 MVA turbo-generator. The effects of a static eccentricity on the shaft voltage were successfully determined firstly through FEM simulation and then verified with physical measurements. Shaft voltages can be used to diagnose static eccentricity, future work should investigate other faults. In addition, computer simulation was found to be effective and simulation and measurements of operating machines (such as turbo-generators) should be considered.
35
Cheng, Wan-Hsueh, and 鄭莞學. "Design of High-Voltage Generator with Low Supply Peak Current for Biomedical Applications." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/u7rfcy.
Повний текст джерелаАнотація:
碩士國立交通大學
電子工程學系 電子研究所
104
Nowadays, due to the development of biomedical science and electronics, electrical stimulation had been proven can recover some physical functions of patients by current stimulation such as retinal stimulation, cochlear implant and suppression of epileptic seizure. Because the impedance of tissues is large, the voltage between tissues would be high when the stimulator driver deliver stimulus current. Therefore, we need to generate high voltage and high voltage tolerant stimulus drivers. Charge pump can generate high positive voltage or high negative voltage from low voltage by different charge pump circuit. A positive charge pump and a negative charge pump has been designed to generate high voltage and negative without gate-reliability issues in low voltage CMOS process. By measurement, the charge pumps can output regulated voltage about 10.8V and maximum current 3.5mA. The output voltage is regulated by PFM control feedback. The maximum output current is 3.5mA. The clock of each charge pump stage has phase shift different from each other, which can reduce the maximum peak current from 3.3V supply. The charge pump also adopt 4-phase clock scheme, which can reduce the return-back leakage and increase the charge pump’s efficiency. The charge pump circuit is fully on chip and had been fabricated in TSMC 0.18μm 1.8-V/3.3-V CMOS process.
36
Adhip, *. "Active Power Flow Tracing for Preventive Control in Deregulated Power Systems." Thesis, 2017. http://etd.iisc.ernet.in/2005/3633.
Повний текст джерелаАнотація:
Modern day power systems present an open access environment, inspiring participation from small scale and large power suppliers. With multiple players in the system driven by the market, proper monitoring and control of system becomes a major concern. This transformation is accompanied by dynamic consumption patterns and rising power demands. The expanding network encompassing EHV/AC network, HVDC and FACTS devices, along with increased penetration of renewable sources, viz. solar and wind energy at medium and low voltage levels, adds to the problem.
Independent System Operators (ISO) are entrusted with ensuring smooth operation, and employing proper preventive measures to eliminate a possible cascade tripping leading to a partial or large-scale blackout. To aid the operator in the process of ensuring secure operation of the grid, there are many tools that provide required information and guidance. Power flow tracing is one such tool that aids the operator in congestion management, transmission pricing, transaction evaluation, loss allocation and reactive power optimization.
In this thesis, a novel active power flow tracing approach is proposed that takes into account, the real-time operating conditions and network topology. It provides the decomposition of active power flow in a line into respective components injected by various generators in the system. It also provides the contribution of the generators to various loads in the system. The approach is simple and computationally fast, making it an ideal tool to aid preventive control decisions.
Based on the proposed active power flow tracing, a congestion management approach is developed. The approach indicates the least number of generators that need to be coordinated for generation rescheduling, so as to alleviate overloading in affected transmission lines and transformers. The approach also takes into consideration the operating constraints on the system, while computing the optimal rescheduling amongst selected generators using LP technique.
The thesis also presents a real power loss allocation approach based on the proposed power flow tracing. Loss allocation is an important part of tariff design as the cost associated with losses amounts to a sizable fraction of total revenue collected from the loads. The approach provides information as to how losses are distributed among loads and how much each generator is providing for the loss share of each load.
The approaches developed in the thesis are illustrated on a sample 10-bus equivalent system, IEEE 30-bus, and IEEE 39-bus systems. Results for typical case studies are presented for practical systems of 72-bus equivalent and 203-bus equivalent of Indian Southern grid.
37
Cheng, Chin-Hung, and 鄭欽鴻. "Bandgap Reference Voltage Generator." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/10794634026978236467.
Повний текст джерелаАнотація:
碩士國立臺灣大學
電子工程學研究所
92
Precision voltage reference plays an important role in modern integrated circuits systems. It can produce a stable reference voltage insensitive to the variations of supply voltage and temperature. Voltage references are widely adopted in many integrated circuits, such as A/D or D/A converters, operational amplifiers, and linear regulators. They are used for defining input/output voltage range, biasing current source of differential pairs, and providing a comparison reference for comparators, etc. The objective of this thesis is to design a bandgap reference voltage generator with input voltage 3V to 6V and output voltage around 1.25V. This reference voltage is intended for using in low dropout linear regulators (LDO). A pre-regulator circuit feeds the bandgap circuit with a regulated 2V to lower the supply voltage sensitivity. A new bandgap circuit topology is also presented. The final bandgap reference with supply voltage sensitivity less than 0.3 mV/V, and temperature coefficient around 7 ppm/℃, and power consumption lower than 100μW is achieved.
38
Baek, Jeihoon. "Robust Generator System Using PM Assisted Synchronous Reluctance Generator with Current-fed Drive." 2009. http://hdl.handle.net/1969.1/ETD-TAMU-2009-12-7319.
Повний текст джерелаАнотація:
The growth of embedded generation and portable electrical installations has led
to an increased demand for low cost, flexible and reliable generator systems for military
and commercial applications. An interior permanent magnet (IPM) machine has high
power density due to its reluctance torque and magnetic torque components so it can
produce a large constant power-speed range. However, an IPM machine needs
demagnetizing current at high-speed during the flux-weakening region and thus develops
an inverter shutdown problem in an uncontrolled generator mode operation. In order to
overcome the disadvantages of the IPM machine, the permanent magnet assisted
synchronous reluctance generator (PMa-SynRG) can be a good solution for low cost,
high efficiency reliable generator systems. A PMa-SynRG can produce a high efficiency
drive by utilizing the proper amount of magnet and reluctance torque. This work
proposes a PMa-SynRG with two flux barriers and permanent magnets embedded in the
second layer of the rotor. A neodymium magnet (NdFeB) was used as permanent magnets in the rotor to prevent demagnetization. Finding the minimum amount of
magnet is one of the goals of the optimization process.
The objectives of this work are to build an optimal design for the 3kW generator
and an advanced power electronics converter for the PMa-SynRG drive system. In order
to find the optimized 3kW machine, a Lumped Parameter Model (LPM) was used to
achieve fast computation, and Differential Evolution Strategy (DES) was used to embed
the LPM in an efficient numerical optimization routine to identify optimum designs.
Finite Element Analysis (FEA) was used for test performance of optimum designs. On
the basis of differences between LPM and FEA, model predictions were used to fine
tune the LPM model. For new optimum design converges, numerical optimizations and
iterations were performed to produce LPM and FEA predictions.
For the drive system, the thyristor based, current-fed drive is much simpler and
has lower power losses compared to the pulse width modulation (PWM) drive.
Eliminating the requirement for self-controlled switches is a distinct advantage for lower
cost. Another feature of the developed current-fed drive is its inherent capability to
provide generating action by making the PMa-SynRG operates as a generator, rectifying
the phase voltages by means of the three-phase rectifier and feeding the power into the
load. These features make the current-fed drive a good candidate for driving any type of
synchronous generators including the proposed PMa-SynRG.
39
Vekanuru, Sasikiran. "Induction Generators Behavior Under Unbalanced Voltage And Fault Conditions." Thesis, 2010. http://etd.iisc.ernet.in/handle/2005/1423.
Повний текст джерелаАнотація:
In this thesis first the behavior of induction generators under unbalanced voltage conditions is studied. In this context, first the existing schemes for characterizing the unbalance in simple ways have been studied. The two schemes IEC, NEMA which are in use to quantify the unbalance, as an unbalance factor require the use of complex algebra. A new scheme to characterize voltage unbalance, without using any complex algebra has been proposed and its effectiveness is compared with the NEMA scheme. The performance of the induction generators under unbalanced voltage conditions is first studied using the symmetrical component approach and a detailed simulation. The machine currents for the same unbalanced conditions are estimated using the proposed scheme and its effectiveness is highlighted. Existing approximate schemes based on unbalance factor do not consider the phase differences between positive and negative sequence voltages while estimating currents. A method of including this feature is proposed here. A simple way to find the maximum line current among the three phases as a function of the positive and negative voltages has been proposed. Knowing the positive, negative sequence voltages and the angle between them, a scheme to compute the generator currents under unbalanced conditions is proposed. Finally a few affecting the machine heating due to unbalanced currents have been studied.
The nature of the induction generator fault currents is studied to understand their implication on the system performance. First the fault currents that have been recorded from experiments on relatively small induction motors(26kW and 122kW) are compared with those obtained through detailed dynamic simulation, in order to validate the usage of the detailed dynamic simulations to study the fault current behavior of the induction machines in the absence of experimental or field records. In order to assess the impact of error in the measured machine parameters on the estimated fault current values, the sensitivity of the estimated values of fault currents to machine parameter variations is investigated. The fault currents in large grid connected induction generators (3MW to 500kW) have been estimated through detailed simulation. The effect of the instant of fault (w.r.t voltage cycle), input load levels and shunt capacitors on the fault current values is investigated. An eigen value analysis of the generator model has been carried out to understand the reasons for the observed behavior using the linearized machine model. Fitting functions have been adopted to quantify the fault currents, in order to facilitate comparison of fault currents.
A method of including induction generators into the system fault studies has been proposed. Methods of choosing proper sequence impedances for representing the induction generator have been developed and validated using simulated values of balanced and unbalanced fault currents. Simulations of self excited generators have been used for determining the unbalanced fault currents, so as to ensure that the induction generator fault currents correspond to only those contributed by the machine. The impact of the induction generators penetration on the short circuit levels is investigated considering a 14 bus test system by incorporating the proposed induction generator models in a system level fault study.
40
Cheng, Shen-Jen, and 鄭舜仁. "On the design of a current generator." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/01335115403241662307.
Повний текст джерелаАнотація:
碩士國立臺灣海洋大學
系統工程暨造船學系
99
A 3 kW ocean current generator will be designed and tested in large cavitation tunnel at NTOU(National Taiwan Ocean University). The propeller lifting line theory will be applied to design the turbine blade at 3.2 m/s current speed. The power generated by different diameters of turbine blade and its corresponding optimal revolutions will be calculated. The efficiency of three blades turbine is higher than that of two blades turbine. A three blades turbine with 0.8 m diameter can reach 3 kW. Due to the 6.2 rps low shaft rotational speed at design inflow speed, a planet gear is used to increase the speed 7 times. Thus, the torque and the size of the generator is reduced correspondingly. The generator is submersible type, and cooling with the sea water. Because the planet gear is not watertight, the seals are important in order to keep watertight. Besides, a flexible coupling between gear and generator is installed to reduce the vibration. A power electronic system which can convert the generated power to 110 V and 60 Hz, will also be installed. Besides, a mechanism which can make the generator always to direct to the inflow, is designed, in order to keep the best efficiency when the current direction is changed.
41
CHEN, BANG-LI, and 陳邦立. "A PVT Insensitive All-MOS Current Generator." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/n6yr93.
Повний текст джерелаАнотація:
碩士國立臺北大學
電機工程學系
105
This paper proposes a new design of current source, which is All-MOS transistor designed without bipolar transistor and resistance component. Therefore, the current source has no negative effects of extra process variation and more mask cost.Considering various processes, voltages (1.4V to 1.98V) and temperature (-400C to 1200C), in these extreme conditions the error variation of current is much lower than 1%; therefore, the current source has a low sensitivity of process, voltage, temperature variation.In traditional application, the high frequency oscillator tail current is very sensitive to temperature variation, making the chip yields fall. Therefore, this current source circuit can be applied in oscillator to solve the issue because of low sensitivity of process, voltage and temperature. Moreover, this current source help oscillator to prove high-yield, low-power and high spread spectrum performance of the spread spectrum clock generator.The output frequency of the chip is 6GHz, and this chip was fabricated in TSMC 0.18um 1P6M process. The design in this paper uses 1.8V supply voltage, and chip area is 1.29 × 0.99mm2, and the total power consumption of the core circuit is about 20mW, and center operating frequency is 6GHz and downward expansion of 5000ppm, Electromagnetic interference suppression reduced 20dBm more.
42
Luo, Fang-Bo, and 駱芳柏. "Multipurpose high frequency high voltage pulse trigger generator." Thesis, 1986. http://ndltd.ncl.edu.tw/handle/65439772560997215850.
Повний текст джерела
43
Huang, Li-Hsuan, and 黃禮宣. "A PLL-Based Clock Generator With Voltage Regulator." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/50051026138818857863.
Повний текст джерелаАнотація:
碩士南台科技大學
電子工程系
93
Every product has different specification, so it is meaningless to design all specification to the best and produce high cost. This paper is to modify some circuit based on product specification in order to make balance of cost and specification. We start to study how to use the least cost to reduce Locking time and increase locking speed of phase lock loops without modifiying original circuit characteristics. In addition, VCO circuit in the system is a high pass filter. Noise of VCO will make contribution to output frequency. So, we must use technique of designing circuit and modify VCO structure to decrease phase noise and design a phase lock loops with low-jitter characteristic further. Therefore, this study will introduce and discuss each product specification, bandwidth design and stability. The paper use the function of Voltage Regulator Circuit to improve the characteristic of Phase Lock Loops by adding power on reset circuit and Voltage Regulator circuit. In fact, if Band Width of Low Pass Filter in Phase Lock Loops system is designed small, jitter will decrease while setting speed will increase. In other words, the relationship of locking time and phase noise is trade-off. When power is on, the result of setting speed don’t always achieve our expectation. Therefore, we can try to advance the initial value of predicted oscillator’s frequency in the transient stage of power on. This approach will save the time of which the system compares frequency. For the part of phase detector, it can stable time speedily by adopting synchronism concept to speed up the setting speed in system. By doing so, the initial phase noise can be kept and setting speed in system can be increased. This is a new idea without relative international papers and I believe this design will make contribution to the design of Phase Lock Loops. Intial ideas will make application in consuming products, such as wake-up system of sleep mode in PDA/micro-control, and apply to make fast stability in changing frequency.
44
Chang, Tze Hwa, and 張志華. "Implement of Voltage Regulation of Synchronous Generator Using." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/18908198559335627209.
Повний текст джерела
45
Cheng, Ying-Tsung, and 鄭穎聰. "Design of High Frequency High Voltage Corona Generator." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/a35q68.
Повний текст джерелаАнотація:
碩士國立虎尾科技大學
電機工程研究所
97
This study is mainly to accomplish a high-frequency high-voltage corona generator, its power supply is provided by a series load-resonant converter, and the high-frequency high-voltage corona discharger is utilized to generate coronas. This research utilize the power supply composed of a series load-resonant converters, MOSFET as the high-frequency high-voltage switch, and made use of the high-frequency step-up transformer to output high-frequency high-voltage power, so that the high-voltage discharge electrode could generate coronas. The high-frequency high-voltage transformer and corona discharge electrode all belong to the resonant power circuit. The high-frequency high-voltage transformer contains considerable stray capacitance. This study utilized the inductance measurement method to construct the equivalent circuit of transformers which contained stray capacitance, applied the circuit measurement analysis to construct the equivalent circuit of corona discharge electrode, integrated the equivalent circuit of high-voltage discharge of corona dischargers, as well as to employ the IsSpice software for circuit simulation in order to verify the accuracy of equivalent circuits constructed in this research. After deriving the equivalent model and cooperating with the analysis of the resonant circuit, this research set up the design criteria of resonant parameters matching regarding the high-frequency high-voltage power supply of corona. Finally, a 1kVA series load-resonant converter was accomplished with its AC input voltage being 220V/60Hz and the peak output being 8kV/22kHz to drive the high-voltage corona discharger.
46
Chen, Isaac Y., and 陳曜洲. "Power-Efficient CMOS On-Chip High Voltage Generator." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/14283459324884808512.
Повний текст джерелаАнотація:
碩士國立交通大學
電子研究所
82
Analog Circuits that can operate in a low supply voltage environment are critical for portable mixed-mode systems. The objective of this research is to investigate a circuits techniques for analog CMOS integrated circuits so that they can operate with a power supply voltage below 2 V. In order to minimize power dissipation, a framework for low-power analog signal processing is proposed. The framework contains a fully differential signal path operating between two low-voltage power rails, while analog switches are controlled by signals with high voltage generated from a low-power on-chip high voltage generator (HVG). A low-power on-chip high voltage generator (CPG) and a clock pattern generator for control of analog CMOS switches are under investigation. Low-power analog CMOS switches require digital high-voltage control signals. The digital high-voltage control signals have a supply voltage above double Vdd to ensure analog CMOS switches at the adequate ON state. In order to meet above specification, the efficient- power CMOS on-chip high voltage generator and the analog switches control for the 1.2 V CMOS analog-to-digital converter (ADC) is studied.
47
Chen, Chih-Wei, and 陳致瑋. "Low Voltage Wide Swing Second Generation Current Conveyor." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/65168610546451334486.
Повний текст джерелаАнотація:
碩士國立中山大學
電機工程學系研究所
91
We developed low voltage wide swing second generation current conveyors(CCII) with the application to a insensitive Butterworth second-order low-pass filter. All circuits are designed using the parameters of TSMC 1P4M 0.35um process. The minimum supply voltage of CCII(1) circuit is |Vtp|+3Vod. The supply voltage of CCII(2) circuit is |Vtp|+2Vod. The voltage swing of the CCIIs are almost rail to rail.
48
吳榮田. "Standard CMOS Low Operating Voltage Linear Type Bandgap Reference Voltage Generator." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/35770322350884476361.
Повний текст джерелаАнотація:
碩士國立臺灣大學
電機工程學研究所
90
For many modern analog circuits, it is very important to generate a power supply voltage and temperature independent reference voltage to improve the performance of circuits such as accuracy, reliability, yield rate and so on. In the past the linear type CMOS bandgap reference voltage generator was chosen as a reliable reference voltage source for many years because of its working very well. But the traditional linear type CMOS bandgap reference voltage generator cannot work properly when the power supply voltage is lower than 2V. Due to the progress of CMOS process and the application of ICs, the power supply voltage of many ICs has to be reduced less than 2V in the future. A novel architecture of current summation type linear CMOS bandgap reference voltage generator is proposed here to afford a reliable bandgap reference voltage generating circuit that can operate at 1.3V power supply perfectly.
49
Lee, Chia-Yu, and 李佳祐. "A Low-Voltage Low-Temperature-Coefficient CMOS Bandgap Voltage Reference Generator." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/60462464118919911604.
Повний текст джерелаАнотація:
碩士國立臺灣大學
電子工程學研究所
94
Voltage references play an important role in modern integrated circuits systems. They are widely apdopted in many integrated circuits, such as A/D or D/A converters, power-management system, operational amplifiers, and linear regulators. They are used for defining input/output voltage range, baising current source of differential pairs, and providing a comparison reference for comparators. A precision voltage reference must be, inherently, well-defined and insensitive to temperature, power supply and load variations. The objective of this thesis is to design a bandgap voltage reference with input voltage 1.8V to 3.3V and output voltage around 1.2V. The bandgap voltage reference is intended for using in low dropout linear regulators (LDO). In order to reduce the supply voltage, the voltage reference is using low voltage operational amplifers in place of using conservative cascade current mirror. In addition, this thesis designs a 1-V bandgap voltage reference with temperature compensation to suit the current of low supply voltage. During design and analysis stages, the HSPICE is used for the simulation, modification and verification of the circuit.
50
Yu, Li-Chin, and 游力瑾. "High-Voltage Generator with Multi-Stage Selection in Low-Voltage CMOS Process." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/ce3g86.
Повний текст джерела