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

Circuito integrado de condicionamento de sinais para sensores wire-mesh aplicados ao monitoramento de escoamentos multif?sicos

Sales Filho, Jos? Batista de 16 December 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-03T19:47:15Z No. of bitstreams: 1 JoseBatistaDeSalesFilho_DISSERT.pdf: 5253037 bytes, checksum: 306cef0f9ed7e39467276cd7982f3884 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-06T19:49:23Z (GMT) No. of bitstreams: 1 JoseBatistaDeSalesFilho_DISSERT.pdf: 5253037 bytes, checksum: 306cef0f9ed7e39467276cd7982f3884 (MD5) / Made available in DSpace on 2017-04-06T19:49:23Z (GMT). No. of bitstreams: 1 JoseBatistaDeSalesFilho_DISSERT.pdf: 5253037 bytes, checksum: 306cef0f9ed7e39467276cd7982f3884 (MD5) Previous issue date: 2016-12-16 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Em diversos campos da ind?stria petroqu?mica e nuclear, o controle e monitoramento de escoamentos compostos de misturas de ?leo, g?s e ?gua (escoamentos multif?sicos) v?m motivando o desenvolvimento de t?cnicas de investiga??o baseadas na gera??o de imagens por tomografia. Fen?menos como propaga??o de bolhas de g?s possuem din?micas r?pidas que exigem dos sistemas de monitoramento uma boa resolu??o temporal. Com o intuito de melhorar tais requisitos temporais em rela??o as t?cnicas de imagem j? consolidadas, foram desenvolvidos sensores do tipo wire-mesh ao longo da ?ltima d?cada. Estes sensores, que s?o inseridos dentro das tubula??es, s?o constitu?dos por uma malha de eletrodos que realizam medi??es de imped?ncia el?trica, que pode ser convertida nas propriedades el?tricas dos fluidos. Apesar da caracter?stica intrusiva, imagens do fluxo multif?sico s?o geradas sem a necessidade de algoritmos iterativos de reconstru??o. ? proposto neste trabalho um circuito integrado (CI) para realizar o condicionamento de uma malha de sensores wire-mesh 4x4, aplicado ? determina??o da fra??o de fases em fluxos multif?sicos. A integra??o reduz o tamanho dos circuitos de condicionamento, comparado ?s implementa??es dos sistemas existentes que utilizam componentes discretos, e tamb?m oferece op??es de customiza??o para melhorar o consumo de energia. O chip ? composto dos seguintes blocos: um amplificador de interface, que converte as correntes provenientes dos sensores em tens?o; um demodulador s?ncrono a fase, que fornece sinais de tens?o em fase e em quadratura que s?o fun??es das propriedades el?tricas dos fluidos (permissividade e condutividade); e de um filtro passa-baixas que antecede a convers?o anal?gico-digital, a ser feita fora do chip. O foco deste trabalho ? apresentar o projeto dos blocos do amplificador de interface e do filtro passa-baixas. O circuito integrado foi projetado para uma tecnologia CMOS padr?o de 130 nm. A valida??o do funcionamento do circuito ? feita a partir de simula??es p?s-leiaute. / In many petrochemical and nuclear industry applications, monitoring of streaming oil-watergas- mixtures (multiphase flows) has been motivating the development of investigation methods based on tomographic imaging. Some investigated phenomena, such as gas bubble propagation, feature fast-changing dynamics, thus demanding a good time resolution of monitoring systems. In order to achieve faster imaging methods compared to established tomographic techniques, wire-mesh sensors were developed over the last decade. These sensors, which are inserted inside pipelines, are composed of an electrode mesh that performs electric impedance measurements, which can be converted in fluid electrical properties. Despite their intrusive nature, multiphase flow images can be generated without iterative reconstruction algorithms. It is proposed in this work an integrated circuit (IC) to perform a 4x4 wire-mesh sensor signal conditioning, applied to phase fraction calculations of multiphase flows. The circuit integration reduce the size of conditioning circuits, in comparison with established systems which use discrete components, and also offers customization options to enhance power consumption efficiency. The chip comprises the following blocks: an interface amplifier that converts the sensor output currents into voltage signals; a phase syncronous demodulator, which provides in-phase and quadrature voltage signals that are functions of the main fluid electrical parameters (permittivity and conductivity); and a low-pass filter, prior to the off-chip analog-to-digital conversion. This work focuses on the project of the interface amplifier and the low-pass filter. The circuit was designed for a 130-nm standard CMOS technology. The IC validation is performed via post-layout simulations.

Page generated in 0.0408 seconds