No description available.

No description available.

No description available.

[pt] A falta de recursos e a questão ecológica têm limitado a expansão do sistema de transmissão. Esta realidade, em conjunto com o crescimento da carga, faz com que os sistemas elétricos trabalhem bastante carregados. Esta nova condição pode levar a situações de colapso de tensão. Métodos para avaliação do carregamento da rede de transmissão tornaram-se necessários e imprescindíveis para que se possa entender o funcionamento do sistema nestas condições e possibilitar a sua operação de modo correto. Ferramentas analíticas têm sido usadas para reforço das condições de segurança de tensão do sistema em tempo real, se for avaliado que o sistema não é suficientemente seguro. Ações operativas de controle são determinadas, para mover o estado do sistema para um ponto de operação seguro. Entretanto, ferramentas de avaliação e reforço não são a única necessidade. As mesmas ações de controle, que podem afastar o sistema de uma situação de instabilidade de tensão, também podem ter efeito oposto ao esperado e contribuir para o problema, podendo até mesmo levar o sistema ao colapso. Portanto, é necessário o desenvolvimento de uma ferramenta computacional para avaliar a adequação de ações de controle de tensão. Neste trabalho é proposta uma ferramenta computacional, desenvolvida com base no sistema linearizado das equações de fluxo de carga, incluindo equações de controle de tensão e limites, para a avaliação do efeito das ações de controle de tensão. São obtidos índices que permitem avaliar se a ação de controle é adequada ou não. Além disso, esses índices podem avaliar a interdependência entre os controles, porque além de indicarem o efeito do controle sobre a tensão da barra controlada, podem indicar também o efeito do controle sobre as outras barras de tensão controlada do sistema. Estes índices podem ser obtidos de forma extremamente rápida, e são adequados para uso em tempo-real. / [en] The lack of investments and the ecological matter have limited the expansion of the transmission system. This reality, together with the load growth, makes the electric systems to work heavy loaded. This new condition can lead to situations of voltage collapse. Methods for evaluation the transmission network loading became necessary and indispensable for understanding system performance under these conditions and for making possible secure operation. Analytic tools have been used to evaluate the voltage security of the system in real time. If it is evaluated that the system is not sufficiently secure in relation to voltage, control actions can be determined, in order to move the state of the system for a secure operation point. However, these tools are not the only need. The same control actions that can move away the system from a situation of voltage instability, can also have opposite effect and contribute for worsening the problem, perhaps leading to system collapse. Therefore, it is necessary the development of computational tools to evaluate the adequacy of these control actions. In this work it is proposed a computational tool, based on the linearized set of power flow equations, including equations for voltage control and limits, for the evaluation of the effect voltage control actions. Indexes that allow the evaluation whether the control action is adequate or not are obtained. The indexes can also evaluate the interdependence among the controls, because besides indicating the effect of the control action on the voltage of the controlled bus, they can also indicate the effect on the other voltage controlled buses. The indexes can be calculated in an extremely fast way, and are appropriate for use in real-time operation.

Yuen Chi Lap. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 88-94). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Aims --- p.2 / Chapter 1.3 --- Contributions --- p.3 / Chapter 1.4 --- Thesis Organization --- p.4 / Chapter 2 --- Background and Literature Review --- p.5 / Chapter 2.1 --- Introduction --- p.5 / Chapter 2.2 --- Vibration-to-Electrical Transducer --- p.6 / Chapter 2.2.1 --- Electromagnetic (Inductive) Power Conversion --- p.6 / Chapter 2.2.2 --- Electrostatic(Capacitive) Power Conversion --- p.8 / Chapter 2.2.3 --- Piezoelectric Power Conversion --- p.9 / Chapter 2.3 --- Wireless Sensor Platform Examples --- p.11 / Chapter 2.3.1 --- MICA[13] from UC Berkeley[49] --- p.11 / Chapter 2.3.2 --- WINS[48] from UCLA[51] --- p.13 / Chapter 2.3.3 --- Wong's Infrared System[5] --- p.13 / Chapter 2.4 --- Summary --- p.14 / Chapter 3 --- Micro Power Generator --- p.16 / Chapter 3.1 --- Introduction --- p.16 / Chapter 3.2 --- MEMS Resonator --- p.18 / Chapter 3.2.1 --- Laser-machinery --- p.18 / Chapter 3.2.2 --- Electroplating Fabrication --- p.18 / Chapter 3.3 --- Voltage Multiplier --- p.19 / Chapter 3.4 --- "Modeling, Simulations and Measurements" --- p.21 / Chapter 3.5 --- Summary --- p.30 / Chapter 4 --- Low Power Wireless Sensor Platform --- p.37 / Chapter 4.1 --- Introduction --- p.37 / Chapter 4.2 --- Generic Platform --- p.37 / Chapter 4.2.1 --- Startup Module and Power Management --- p.38 / Chapter 4.2.2 --- Control Unit --- p.43 / Chapter 4.2.3 --- Input Units (Sensor Peripherals) --- p.46 / Chapter 4.2.4 --- Output Units (Wireless Transmitters) --- p.48 / Chapter 4.3 --- Summary --- p.57 / Chapter 5 --- Application I - Wireless RF Thermometer --- p.59 / Chapter 5.1 --- Overview --- p.59 / Chapter 5.2 --- Implementation --- p.60 / Chapter 5.2.1 --- Prototype 1 --- p.60 / Chapter 5.2.2 --- Prototype 2 --- p.60 / Chapter 5.2.3 --- Prototype 3 --- p.62 / Chapter 5.2.4 --- Prototype 4 --- p.63 / Chapter 5.3 --- Results --- p.65 / Chapter 5.4 --- Summary --- p.67 / Chapter 6 --- Application II - 2D Input Ring --- p.70 / Chapter 6.1 --- Overview --- p.70 / Chapter 6.2 --- Architecture --- p.70 / Chapter 6.3 --- Software Implementation --- p.72 / Chapter 6.3.1 --- Methodology --- p.72 / Chapter 6.3.2 --- Error Control Code --- p.73 / Chapter 6.3.3 --- Peripheral Control Protocol --- p.75 / Chapter 6.4 --- Results --- p.77 / Chapter 6.5 --- Summary --- p.83 / Chapter 7 --- Conclusion --- p.84 / Chapter 7.1 --- Micro power generator --- p.84 / Chapter 7.2 --- Low power wireless sensor applications --- p.85 / Chapter 7.2.1 --- Wireless thermometer --- p.85 / Chapter 7.2.2 --- 2D input ring --- p.86 / Chapter 7.3 --- Further development --- p.86 / Bibliography --- p.88 / Chapter A --- Schematics --- p.97

Chung, Wai Fung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 98-100). / Abstracts in English and Chinese. / 摘要 --- p.III / ACKNOWLEDGEMENT --- p.IV / CONTENTS --- p.V / LIST OF FIGURES --- p.VIII / LIST OF TABLES --- p.X / LIST OF TABLES --- p.X / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Receiver Architecture --- p.3 / Chapter 1.2.1 --- Zero-IF Receivers --- p.4 / Chapter 1.2.2 --- Low-IF Receivers --- p.6 / Chapter 1.2.2.1 --- Hartley Architecture --- p.7 / Chapter 1.2.2.2 --- Weaver Architecture --- p.9 / Chapter 1.3 --- Image-rejection ratio --- p.10 / Chapter 1.4 --- Thesis Organization --- p.12 / Chapter CHAPTER 2 --- FUNDAMENTALS OF OSCILLATOR --- p.13 / Chapter 2.1 --- Basic Oscillator Theory --- p.13 / Chapter 2.2 --- Varactor --- p.15 / Chapter 2.3 --- Inductor --- p.17 / Chapter 2.4 --- Phase noise --- p.22 / Chapter 2.4.1 --- The Leeson ´ةs phase noise expression --- p.24 / Chapter 2.4.2 --- Linear model --- p.25 / Chapter 2.4.3 --- Linear Time-Variant phase noise model --- p.28 / Chapter CHAPTER 3 --- FULLY-INTEGRATED CMOS OSCILLATOR DESIGN --- p.31 / Chapter 3.1 --- Ring oscillator --- p.31 / Chapter 3.2 --- LC oscillator --- p.33 / Chapter 3.2.1 --- LC-tank resonator --- p.34 / Chapter 3.2.2 --- Negative transconductance --- p.36 / Chapter 3.3 --- Generation of quadrature phase signals --- p.39 / Chapter 3.4 --- Quadrature VCO topologies --- p.41 / Chapter 3.4.1 --- Parallel-coupled QVCO --- p.41 / Chapter 3.4.2 --- Series-coupled QVCO --- p.46 / Chapter 3.4.3 --- QVCO with Back-gate Coupling --- p.47 / Chapter 3.4.4 --- QVCO using superharmonic coupling --- p.49 / Chapter 3.5 --- Novel QVCO using back-gate superharmonic coupling --- p.52 / Chapter 3.5.1 --- Tuning range --- p.54 / Chapter 3.5.2 --- Negative gm --- p.55 / Chapter 3.5.3 --- Phase noise calculation --- p.56 / Chapter 3.5.4 --- Coupling coefficient --- p.57 / Chapter 3.5.5 --- Low-voltage and low-power design --- p.59 / Chapter 3.5.6 --- Layout Consideration --- p.61 / Chapter 3.5.6.1 --- Symmetrical Layout and parasitics --- p.61 / Chapter 3.5.6.2 --- Metal width and number of vias --- p.63 / Chapter 3.5.6.3 --- Substrate contact and guard ring --- p.63 / Chapter 3.5.7 --- Simulation Results --- p.65 / Chapter 3.5.7.1 --- Frequency and output power --- p.65 / Chapter 3.5.7.2 --- Quadrature signal generation --- p.67 / Chapter 3.5.7.3 --- Tuning range --- p.67 / Chapter 3.5.7.4 --- Power consumption --- p.68 / Chapter 3.5.7.5 --- Phase noise --- p.69 / Chapter 3.6 --- Polyphase filter and Single-sideband mixer design --- p.70 / Chapter 3.6.1 --- Polyphase filter --- p.72 / Chapter 3.6.2 --- Layout Consideration --- p.74 / Chapter 3.6.3 --- Simulation results --- p.76 / Chapter 3.7 --- Comparison with parallel-coupled QVCO --- p.78 / Chapter CHAPTER 4 --- EXPERIMENTAL RESULTS --- p.80 / Chapter 4.1 --- Test Fixture --- p.82 / Chapter 4.2 --- Measurement set-up --- p.84 / Chapter 4.3 --- Measurement results --- p.86 / Chapter 4.3.1 --- Proposed QVCO using back-gate superharmonic coupling --- p.86 / Chapter 4.3.1.1 --- Output Spectrum --- p.86 / Chapter 4.3.1.2 --- Tuning range --- p.87 / Chapter 4.3.1.3 --- Phase noise --- p.88 / Chapter 4.3.1.4 --- Power consumption --- p.88 / Chapter 4.3.1.5 --- Image-rejection ratio --- p.89 / Chapter 4.3.2 --- Parallel-coupled QVCO --- p.90 / Chapter 4.3.2.1 --- Output spectrum --- p.90 / Chapter 4.3.2.2 --- Power consumption --- p.90 / Chapter 4.3.2.3 --- Tuning range --- p.91 / Chapter 4.3.2.4 --- Phase noise --- p.92 / Chapter 4.3.3 --- Comparison between proposed and parallel-coupled QVCO --- p.93 / Chapter CHAPTER 5 --- CONCLUSIONS --- p.95 / Chapter 5.1 --- Conclusions --- p.95 / Chapter 5.2 --- Future work --- p.97 / REFERENCES --- p.98

Thesis (M.S. in electrical engineering)--Washington State University, December 2007. / Includes bibliographical references (p. 55-56).

Voltage converters or charge pumps find their use in many circuits. They are extensively used in hand held devices as cell phones, pagers, PDA's and laptops. Some of the important issues relating to design of voltage regulators for handheld devices are size, efficiency and noise. Another important factor to be considered is the discharge characteristic of the various batteries used by the handheld devices. This thesis addresses the issues of tones present in the conventional switched capacitor voltage regulator. An alternate architecture with a delta-sigma control loop to eliminate this problem is proposed. Also discussed is a method to compute the efficiency of switched capacitor charge pumps. A test chip implementing the new architecture was fabricated in a 0.72-micron CMOS process. The results of the test chip verify the improved architecture. / Graduation date: 2002

A novel variation of Rutherford Backscattering Spectrometry (RBS) has been utilized to measure a high voltage collected on an aluminum target by Direct Energy Conversion. The maximum high voltage on the target was measured to be 97.5 kV +/- 2 kV. The resistance of the circuit was then calculated based on the current driving different target voltages. The resistance was calculated to be 199.4GΩ +/- 5%. It was shown that by simply measuring the neutral particles’ energy spectra, the voltage on the target and resistance of the circuit can be found with certainty. The experimental data agree well with previous work and with the scattering theory developed. Thus, the capability of RBS has been extended to measure high voltages generated by direct energy conversion; this is something that has not been done before.

No description available.