Interfacing and operating AC power electronic systems requires rapid and accurate estimation of the phase angle of the power source, and specifically of the positive sequence of the three-phase utility grid voltage. This is needed to ensure reliable operation of the power control devices and of the resulting power flow. However, the quality of this information is undermined by various distortions and unbalanced conditions of the three-phase grid voltage. Phase estimation and power control can both be performed in real time by a DSP, but a DSP typically has limited computational resources, especially in regards to speed and memory, which motivates the search for computationally efficient algorithms to accomplish these tasks. In contrast to conventional PLL techniques, recent approaches have used adaptive amplitude estimation to enhance the acquisition of the phase information, resulting in faster response and improved performance. This thesis presents a novel technique to estimate the phase of the positive sequence of a three-phase voltage in the presence of frequency variations and unbalanced conditions, referred to as hybrid negative sequence adaptive synchronous amplitude estimation with PLL, or H-NSASAE-PLL. The key feature consists of a feedback structure which embeds a positive sequence PLL and an adaptive synchronous negative sequence estimator to enhance the performance of the PLL. The resulting benefits include faster estimation of the phase of the positive sequence under unbalanced conditions with zero steady state error, simplified tuning of PLL parameters to address a wide range of application requirements, robust performance with respect to distortions and PLL parameters, a structure of minimal dynamical order (fifth) to estimate the main signal parameters of interest, simplified discretization, and reduced computational costs, making the proposed technique suitable for real time execution on a DSP. The H-NSASAE-PLL is developed in the Matlab/Simulink environment, and a specialized test signal generator is developed to evaluate its performance. The overall system is executed, and experimental results are produced, in real time, on a dSPACE DS1104 controller board. / Power Engineering and Power electronics

No description available.

Two different topics associated with their respective applications are proposed in this thesis. The first topic is the implementation of a 6-T SRAM cell using dual threshold voltage transistors and low power quenchers. We proposed a SRAM cell with dual threshold voltage transistors. The advantages of such a design is to reduce the access time and maintain data retention at the same time. Besides, the unwanted oscillation of the output data lines caused by large currents is reduced by adding two back-to-back quenchers. The second topic is focused on the implementation of a programmable PLL-based frequency multiplier. Using the method of a phase-locked loop and a programmable divisor to implement a frequency multiplier. ¢Ï synchronous clock signal can be generated by the proposed design. It can also be used in wireless communication systems, e.g. local oscillators.

The loop bandwidth of a fractional-N PLL is a desirable parameter for many applications. A wide bandwidth allows a significant attenuation of phase noise arising from the VCO. A good VCO typically requires a high Q LC oscillator. It is difficult to build an on-chip inductor with a high Q factor. In addition, a good VCO also requires a lot of power. Both these design challenges are relaxed with a wide loop bandwidth PLL. However a wide loop bandwidth reduces the effective oversampling ratio (OSR) between the update rate and loop bandwidth and makes quantization noise from the ΔΣ modulator a much bigger noise contributor. A wide band loop also makes the noise and linearity performance of the phase detector more significant. The key to successful implementation of a wideband fractional-N synthesizer is in managing jitter and spurious performance. In this dissertation we present a new PLL architecture for bandwidth extension or phase noise reduction. By using clock squaring buffers with built-in offsets, multiple clock edges are extracted from a single cycle of a sinusoidal reference and used for phase updates, effectively forming a reference frequency multiplier. A higher update rate enables a higher OSR which allows for better quantization noise shaping and makes a wideband fractional-N PLL possible. However since the proposed reference multiplier utilizes the magnitude information from a sinusoidal reference to obtain phases, the derived new edges tend to cluster around the zero-crossings and form an irregular clock. This presents a challenge in lock acquisition. We have demonstrated for the first time that an irregular clock can be used to lock a PLL. The irregularity of the reference clock is taken into account in the divider by adding a cyclic divide pattern along with the ΔΣ control bits, this forces the loop to locally match the incoming patterns and achieve lock. Theoretically this new architecture allows for a 6x increase in loop BW or a 24dB improvement in phase noise. One potential issue associated with the proposed approach is the degraded spurious performance due to PVT variations, which lead to unintended mismatches between the irregular period and the divider pattern. A calibration scheme was invented to overcome this issue. In simulation, the calibration scheme was shown to lower the spurs down to inherent spurs level, of which the total energy is much less than the integrated phase noise. A test chip for proof of concept is presented and measurements are carefully analyzed. / text

Made available in DSpace on 2014-06-11T19:30:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-11-25Bitstream added on 2014-06-13T18:06:39Z : No. of bitstreams: 1 cardoso_as_dr_ilha.pdf: 731569 bytes, checksum: 5543d0ce31f156eb520e157b32344a2b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Sintetizadores de frequência são circuitos críticos usados largamente em muitas aplicações de temporização. Circuitos PLL apresentam uma boa solução para temporização, mas utilizam geralmente blocos analógicos que são facilmente influenciados em desempenho devidos a instabilidades inerentes aos processos de fabricação e ruídos. Com a evolução dos circuitos e ferramentas para sistemas digitais foi possível a implementação de circuitos que utilizem somente recursos digitais tais como os DLL. Um dos papéis dos sintetizadores é equalizar a fase de um sinal de clock em relação a uma segunda referência adicionando fase entre os sinais. Este trabalho tem como objetivo o desenvolvimento de um circuito DLL com arquitetura flexível e programável para utilização no ajuste de fase e recuperação de sinais. Os blocos digitais foram implementados utilizando ferramentas de alto nível de abstração para avaliação do comportamento funcional. O objetivo final é a implementação do circuito validado em tecnologia CMOS 350 nm da AMS / Frequency Synthesizers are critical circuits widely used in timing applications. PLLs devices had showed a good solution for timing, but they normally because the use analog building blocks that are often influenced by the subtract building process and noises. Nevertheless, after the evolution of complex circuits and development tools it had been possible the implementation of systems that implement only digital resource such as DLL. One of major goals of synthesizers is to equalize the phase between a clock signal and a second reference. This work aims to develop DLL devices that are built in a flexible and reprogrammable architecture for using in decrements or increments in the phase and clock recovery. Digital blocks were implemented using high level abstraction tools for analysis of functional behavior. The main objective is the circuit implementation and validations in CMOS .35 AMS process

京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第18413号 / 情博第528号 / 新制||情||93(附属図書館) / 31271 / 京都大学大学院情報学研究科通信情報システム専攻 / (主査)教授 小野寺 秀俊, 教授 守倉 正博, 教授 佐藤 高史 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

High-performance variable-speed drives, such as PMSM and BLDC, rely on instantaneous torque control. Over the years, several strategies have been investigated in this domain, with the prominent strategies being field-oriented control and direct torque control. Regardless of the strategy employed, a precise rotor position during operation is an essential requirement. While a wide range of sensing technologies to monitor the rotor position have been employed, industries at large presently focus on Hall effect sensors for this application because they are highly cost-effective, low maintenance, noninvasive, and occupy very little space compared to its alternatives. However, the downside of using Hall effect sensors is their low accuracy. In particular, in the application of handheld battery-powered tools, output signals are affected by vibrations and harmonics from the electromagnetic field. Approaches that are being investigated to reduce or eliminate this noise from the signals can be broadly categorized into 1) installation position optimization, 2) filter methods, and 3) measurement model methods. As they are widely cited and easy to implement in the application of handheld battery-powered tools, four filter structures, namely, ANF with PLL, only PLL, SFE, and SFE with PLL, have been investigated in this thesis. This thesis evaluated the filter’s performance when applied to a real-world application of battery-powered tools. The filters were evaluated for their ability to preserve fundamental frequency components and reject harmonic content up to the 5th order. Visual inspections of Lissajous curves, rotor angle curves and generated reference signals provided insights into peculiarities during operation. Operations were categorized into four scenarios to facilitate the examination of filter response during acceleration and steady state in forward and reverse directions. Only performances of ANFPLL and SFE-PLL proved to be satisfactory with some limitations. The SFE filter yielded insignificant results which could be attributed to a lack of feedback mechanism. While the findings presented in this thesis contribute to the understanding of the viability of filter applications in batterypowered tools, additional testing is imperative. This entails the conversion of filter structures into algorithms suitable  for integration within software frameworks, ensuring their practical applicability and efficacy in real-world scenarios. / Högpresterande frekvensomriktare, såsom Permanent Magnet Synchronous Motor (PMSM) och Brushless DC Electric Motor (BLDC), förlitar sig på momentan vridmomentkontroll. Under årens lopp har flera strategier undersökts inom detta område, där de framträdande strategierna är fältorienterad kontroll och direkt vridmomentkontroll. Oavsett vilken strategi som används är en exakt rotorposition under drift ett väsentligt krav. Medan ett brett utbud av avkänningstekniker för att övervaka rotorns position har använts, fokuserar industrier i stort på Hall-effektsensorer för denna applikation eftersom de är mycket kostnadseffektiva, låga underhållskostnader, ickeinvasiva och upptar mycket lite utrymme jämfört med dess alternativ. Men nackdelen med att använda Hall-effektsensorer är deras låga noggrannhet. I synnerhet vid tillämpning av handhållna batteridrivna verktyg påverkas utsignalerna av vibrationer och övertoner från det elektromagnetiska fältet. Tillvägagångssätt som undersöks för att minska eller eliminera detta brus från signalerna kan brett kategoriseras i 1) installationspositionsoptimering, 2) filtermetoder och 3) mätmodellmetoder. Eftersom de är allmänt citerade och lätta att implementera i tillämpningen av handhållna batteridrivna verktyg, fyra filterstrukturer, nämligen Adaptive Notch Filter (ANF) med Phase Locked Loop (PLL), endast PLL, Synchronous Frequency Extractor (SFE) och SFE med PLL, har undersökts i denna avhandling. Denna avhandling utvärderade filtrets prestanda när det tillämpades på en verklig tillämpning av batteridrivna verktyg. Filtren utvärderades med avseende på förmågan att bevara grundfrekvenskomponenten och avvisa övertonsinnehåll upp till 5:e ordningen. Visuella inspektioner av Lissajous-kurvor, rotorvinkelkurvor och genererade referenssignaler gav insikter om egenheter under drift. Operationer kategoriserades i fyra scenarier för att underlätta undersökning av filterrespons under acceleration och stationärt tillstånd i framåt- och bakåtriktning. Endast prestanda av ANF-PLL och SFE-PLL visade sig vara tillfredsställande med vissa begränsningar. SFE-filtret gav obetydliga resultat som kunde tillskrivas bristen på återkopplingsmekanism. Även om resultaten som presenteras i denna avhandling bidrar till förståelsen av användbarheten av filtertillämpningar  i batteridrivna verktyg, är ytterligare tester absolut nödvändiga. Detta innebär omvandling av filterstrukturer till algoritmer lämpliga för integration inom mjukvaruramverk, vilket säkerställer deras praktiska tillämpbarhet och effektivitet i verkliga scenarier.

International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / GLONASS is similar to GPS in many aspects such as system configuration, navigation mechanism, signal structure, etc.. There exists the possibility of receiving and processing GLONASS signals with GPS technology. The frequency plan of the GLONASS system is different from that of GPS. This makes the front-end of GLONASS receiver more complicated. The work here manifests our initial effort in GLONASS receiving. A design scheme is proposed of a C/A code GLONASS receiver.

Nas últimas três décadas os phase locked loops (PLLs) totalmente digitais têm recebido muita atenção devido, principalmente, às vantagens que eles oferecem em comparação aos PLLs analógicos. Essas vantagens incluem melhor desempenho, maior velocidade e confiabilidade, tamanho reduzido e menor custo. Os PLLs também são amplamente utilizados em sistemas de comunicações e em outras aplicações digitais. A presente dissertação é uma contribuição no campo dos PLLs digitais adaptativos e otimizados para a sua implementação em hardware. É feito uma análise de suas características dinâmicas e proposta uma nova estrutura de PLL digital capaz de melhorar a resposta da malha em termos de tempo de aquisição e largura de banda. A Malha Síncrona Digital \"Tanlock\" com Estimação de Frequência e Ganho Adaptativo para Convergência Rápida, como é chamada, foi desenvolvida a partir da malha digital \"Tanlock\", utilizando-se teoremas de ponto fixo e mapas contrativos para determinar as condições de ganho que garantam convergência rápida e melhor utilização da largura de banda. Resultados das simulações são comparados com os obtidos teoricamente para avaliar o desempenho da malha proposta. / In the last three decades, fully-digital Phase-Locked-Loops (PLLs) systems have received a lot of attention due to its advantages in comparison with analog PLLs. These advantages include improved transient response, reliability and also reduced size and cost. The PLLs are widely used in communications systems and many other digital applications. This dissertation is a contribution to the field of digital adaptive PLLs optimized to hardware implementation. Here, a new PLL structure is presented; the Frequency Sensing Adaptive TDTL is an improvement to the classic Time-Delay Tanlock structure, alowing fast convergence to the synchronous states, using fixed-point theorems and contractive maps to determine the gain conditions which ensure the rapid convergence and also providing wider bandwidth. The results of simulations are compared with those obtained theoretically in order to assess the loop performance.

As CMOS processes size continues to shrink, a number of factors limit the ability of analog circuit performance to scale with the process. These issues include smaller transistor intrinsic gains and lower supply voltages. However, scaling continues to increase the speed and decrease the power of digital circuits. In this thesis, an active time-based integrator is proposed to replace amplifiers. The integrator, implemented using highly digital ring oscillators, seeks to take advantage of benefits offered by technology scaling while negating the issues of low gain and low supply voltages. The proposed integrator topology is used in a 20MHz 4th order continuous-time analog filter. Designed in a 90nm CMOS process, the time-based continuous-time filter achieves superior noise and linearity performance compared to state-of-the-art conventional active RC filters in simulations. / Graduation date: 2012 / Access restricted to the OSU Community at author's request from June 17, 2011 - June 17, 2012