Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-24T20:53:39Z No. of bitstreams: 1 joseabrittacosta.pdf: 19821453 bytes, checksum: 97adfa8b62deaa442a2059908995d6b3 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-25T15:23:58Z (GMT) No. of bitstreams: 1 joseabrittacosta.pdf: 19821453 bytes, checksum: 97adfa8b62deaa442a2059908995d6b3 (MD5) / Made available in DSpace on 2017-04-25T15:23:58Z (GMT). No. of bitstreams: 1 joseabrittacosta.pdf: 19821453 bytes, checksum: 97adfa8b62deaa442a2059908995d6b3 (MD5) Previous issue date: 2014-08-29 / O experimento Neutrinos Angra visa desenvolver um detector compacto e novas técnicas para medir o fluxo de antineutrinos das reações nucleares que ocorrem no interior dos reatores de usinas nucleares, permitindo o monitoramento da sua dissipação de energia instantânea e revelando a composição físsil de combustível nuclear. Este trabalho apresenta o desenvolvimento da eletrônica de front-end do Detector Neutrinos Angra. Esta eletrônica deve realizar o condicionamento dos sinais provenientes de tubos fotomultiplicados, visando fornecer ao sistema de aquisição de dados um pulso que facilite a identificação do fluxo de antineutrinos que passa pelo detector. Neste trabalho, as especificações do front-end foram definidas com base nos requisitos do experimento, que são: faixa linear de operação de 0 a 50 fótons; capacidade para identificar um fóton; duração do pulso menor do que alguns µs; largura de banda do pulso menor do que 60 MHz; excursão máxima na saída de até 2 V. Para isto, uma topologia do circuito de front-end foi proposta, sendo composta por quatro subsistemas: circuito de alimentação; circuito de condicionamento do sinal; circuito de controle de offset na saída e de limiar de tensão; e circuito discriminador. Oito módulos foram produzidos para equipar o detector. Neste trabalho, três módulos foram avaliados. Os testes mostraram que o desempenho dos três módulos atenderam as especificações, apresentando uma calibração média de 7,4±0,6 V/V , tempo de subida de 26±1 ns, tempo de descida de 81 ±2,5 ns, largura a meia altura de 74±1 ns, não-linearidade menor do que 2,2% para toda a faixa dinâmica de entrada e a saturação iniciando em aproximadamente 1,4 V. / The Neutrinos Angra Experiment aims to develop a compact detector and new techniques to measure the antineutrinos flow of nuclear reactions occurring inside the nuclear power plant reactors, allowing monitoring of its instant energy dissipation and revealing the composition of fissile nuclear fuel. This study presents the development of the Front-end electronics of the Neutrinos Angra detector. The electronics should perform the conditioning of the signals from photomultiplier tubes, aiming to provide a fast pulse for the data acquisition system whitch could facilitate the identification of the antineutrinos flow through the detector. In this work, the specifications of the front-end were defined based on the experiment requirements, which are: linear operating range 0-50 photons; ability to identify a single photon; the pulse duration less than a few µs; bandwidth of the pulse smaller than 60 MHz; maximum range in the output up to 2 V. For this, a topology of the front-end circuit has been proposed, consisting of four subsystems: power circuit; signal conditioning circuit; offset control circuit and discriminator circuit. Eight modules were produced to equip the detector. In this study three modules were evaluated. Tests showed that the performance of three modules met the specifications, with an average calibration of 7.4±0.6 V/V , rise time of 26 ±1 ns, falltime of 81 ±2.5 ns, width at half height of 74±1 ns, linearity better than 2.2% and saturation starting around 1.4 V.

Conventional wire bond power modules have limited application for high-current operation, mainly because of their poor thermal management capability. Planar power modules have excellent thermal management capability and lower parasitic inductance, which means that the planar packaging method is desirable for high-power applications. For these reasons, a planar power module for an automotive motor drive system was developed, and a gate-driver circuit with an over-current protection was planned to integrate into the module. This thesis discusses a current-sensing method for the planar module, and the integrated gate driver circuit with an over-current protection. After reviewing several current-sensing methods, it becomes clear that most popular current-sensing methods, such as the Hall-Effect sensor, the current transformer, the Shunt resistor, and Rogowski coils, exhibit limitations for the planar module integration. For these reasons, a giant magneto resistive (GMR) magnetic-field detector was chosen as a current-sensing method. The GMR sensor utilizes the characteristics of the giant magneto resistive (GMR) effect in that it changes its resistance when it is exposed to the magnetic-flux. Because the GMR resistor can be fabricated at the wafer level, a packaged GMR sensor is very compact when compared with conventional current sensors. In addition, the sensor detects magnetic-fields, which does not require direct contact to the current-carrying conductor, and the bandwidth of the sensor can be up to 1 MHz, which is wide enough for the switching frequencies of most of motor drive applications. However, there are some limiting factors that need to be considered for accurate current measurement: • Operating temperature • Magnetic-flux density seen by a GMR resistor • Measurement noise If the GMR sensor is integrated into the power module, the ambient temperature of the sensor will be highly influenced by the junction temperature of the power devices. Having a consistent measurement for varying temperature is important for module-integrated current sensors. An experiment was performed to see the temperature characteristics of a GMR sensor. The measurement error caused by temperature variation was quantified by measurement conditions. This thesis also proposes an active temperature error compensation method for the best use of the GMR sensor. The wide current trace of the planar power module helps to reduce the electrical/thermal resistance, but it hinders having a strong and constant magnetic-field-density seen by the GMR sensor. In addition, the eddy-current effect will change the distribution of the current density and the magnetic-flux-density. These changes directly influence the accurate measurement of the GMR sensor. Therefore, analyzing the magnetic-flux distribution in the planar power module is critical for integrating the GMR sensor. A GMR sensor is very sensitive to noise, especially when it is sensing current flowing in a wide trace and exposed to external fields, neither of which can be avoided for the operation of power modules. Post-signal processing is required, and the signal-conditioning circuit was designed to attenuate noise. The signal-conditioning circuit was designed using an instrumentation amplifier, and the circuit attenuated most of the noise that hindered accurate measurement. The over-current protection circuit along with the gate driver circuit was designed, and the concept was verified by experiments. The main achievements of this study can be summarized as: • Characterization of conventional current-sensing methods • Temperature characterization of the GMR resistor • Magnetic-flux distribution of the planar power module • Design of the signal-conditioning circuit and over-current protection circuit / Master of Science

Made available in DSpace on 2016-08-17T14:52:54Z (GMT). No. of bitstreams: 1 Giselia Andrea Lopes Pinheiro.pdf: 458686 bytes, checksum: 82f645a2a8db5a46231ba0ffbdd613c7 (MD5) Previous issue date: 2004-09-30 / Analog, digital and mixed circuits allow their utilization in several different applications. In instrumentation, in order to measure several quantities using different sensors, the conditioning circuit must be programmable to yield different gain and dc level shift values in order to use the maximum A/D converter input span without causing saturation. A procedure for defining and applying the gain an dc level shift values that guarantees the full measurement range with loss of resolution within acceptable limits, taking into consideration implementation practical aspects, like passive components values, is presented in this work. Architecture for implementing this circuit that support both differential and single-end modes of operation is proposed. / Circuitos analógicos, digitais e mistos programáveis permitem a sua utilização em diversas aplicações diferentes. Em instrumentação, para se medir diversas grandezas utilizando sensores diferentes, o circuito de condicionamento deve ser programado para prover diferentes valores de ganho e de compensação de nível cc, de forma a utilizar a máxima faixa de entrada do conversor A/D sem causar saturação. Neste trabalho, descreve-se um procedimento para definição e aplicação dos valores de ganho e de ajuste de nível cc que garante nenhuma perda de faixa de medição e com perdas de resolução dentro de limites aceitáveis, levando em consideração aspectos práticos de implementação, como os valores de componentes passivos. Propõe-se uma arquitetura para implementação deste circuito que proporciona sua operação tanto em modo diferencial quanto em modo de terminação única.

Submitted by Morgana Silva (morgana_linhares@yahoo.com.br) on 2016-07-27T17:45:52Z No. of bitstreams: 1 arquivototal.pdf: 2648831 bytes, checksum: 9541497365622df815ae71c695bd6f89 (MD5) / Made available in DSpace on 2016-07-27T17:45:52Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2648831 bytes, checksum: 9541497365622df815ae71c695bd6f89 (MD5) Previous issue date: 2015-02-24 / In recent decades, the growing demand for miniaturized, portable and autonomous electronics has intensified the search for new and appropriate energy sources. Following this context, the purpose of this work is to develop an energy-autonomous electronic system, powered by magnetic energy harvesting. Being the energy harvesting system composed of an electromagnetic transducer, to capture and convert stray magnetic field around power lines, and an electronic circuit to condition the energy generated by the transducer and provide adequate power for a resistive load of low consumption. An experimental methodology was employed to select the appropriate material for the core of the transducer therefore been conducted many laboratory tests to analyze and compare the performance of the transducers with respect to power and power density provided by the transducers two ferromagnetic materials distinct, the Ferrite and Nanocrystalline Alloy (FeSiB). After analyzing the data, it is concluded that for this application the Nanocrystalline Alloy showed the best results in terms of power density, and therefore, was selected as the material of the toroidal core of the transducer. However, in the output of the secondary coil was observed high voltage peaks, so that could cause damage to electronic devices connected to the coil circuit. Therefore, it chose to divide the secondary coil into two coils, both connected in parallel to reduce the inductance, at end It is found the effectiveness of the solution, because, reduced voltage spikes and kept the magnitude of the effective tension. However, the showed transducer high inductive reactance, due to its physical parameters, in particular, the high permeability, to compensate were used capacitances connected in series with the coil, in order to define the ideal situation for the system provide maximum power for the load. The power conditioning circuit has been designed to power the wireless sensor node nRF24LE1 the Nordic semiconductors, therefore, have been designed a full-wave rectifier, a filter to the capacitor and a voltage regulator. Finally, it can be concluded that an electronic system with energetic autonomy could be implemented, using as power supply the energy harvesting by magnetic induction, and it can be installed in environments in which there is a magnetic field available for "exploited". / Nas últimas décadas, a crescente demanda por circuitos eletrônicos miniaturizados, portáteis e autônomos, vem intensificando a busca por novas e adequadas fontes energéticas. Seguindo este contexto, o propósito desta dissertação é desenvolver um sistema eletrônico energeticamente autônomo, alimentado por colheita de energia magnética. Sendo o sistema de colheita composto por um transdutor eletromagnético, para captar e converter o campo magnético disperso em torno de linhas de potência, e um circuito eletrônico para condicionar a energia gerada pelo transdutor e fornecer a potência adequada para uma carga resistiva de baixo consumo. Uma metodologia experimental foi empregada para selecionar o material adequado para o núcleo do transdutor, por isso, foram realizados diversos testes em laboratório para analisar e comparar o desempenho dos transdutores em relação à potência e a densidade de potência, fornecidas pelos transdutores de dois materiais ferromagnéticos distintos, a Ferrita e a liga Nanocristalina (FeSiB). Após a análise dos dados, concluiu-se que para esta aplicação a liga Nanocristalina apresentou os melhores resultados quanto à densidade de potência, e por isso, foi selecionada como o material do núcleo toroidal do transdutor. Porém, na saída da bobina secundária se observou altos picos de tensão, de modo que poderia ocasionar danos aos dispositivos eletrônicos do circuito conectado a bobina. Portanto, optou-se por fazer a divisão da bobina secundária em dois enrolamentos, ambos ligados em paralelo, para reduzir a indutância, ao final constatou-se a eficácia da solução, pois, reduziu os picos de tensão e manteve a magnitude da tensão eficaz. Contudo, o transdutor apresentou alta reatância indutiva, devido os seus parâmetros físicos, em particular, a alta permeabilidade, para compensá-la foram utilizadas capacitâncias ligadas em série com a bobina, a fim de definir a situação ideal para o sistema fornecer a máxima potência à carga. O circuito de condicionamento de energia foi projetado para alimentar o nó sensor sem fio nRF24LE1 da Nordic semiconductors, para tanto, foram projetados um retificador de onda completa, um filtro à capacitor e um regulador de tensão. Por fim, pode-se concluir que um sistema eletrônico com autonomia energética pode ser implementado, utilizando-se como fonte de alimentação a colheita de energia por indução magnética, e o mesmo pode ser instalado em ambientes nos quais existam um campo magnético disponível para ser “aproveitado”.

The subject of this diploma thesis is to apply the knowledge of thermodynamics when designing parameters of the train air conditioning unit. In the first part, the issue of air conditioning technology, basic types of cooling circuits and description of individual components are outlined. Furthermore, there is an overview of groups of refrigerants and their labelling. In the second part, a calculation of the heat load of the train unit for the limit design conditions of summer and winter operation, including the application of humid air theory are to be found. There is a basic procedure for designing the main components of compressor cooling, which is almost exclusively used in train applications, outlined. The last part contains the procedure for calculating the gains/losses in the distribution channels of the real air conditioning unit M7 and the evaluation of the results. In the appendix, there is an SW in MS Excel program, which can be indicatively used to calculate the total gains/losses of the distribution channels on any air-conditioning unit before the air enters into the train unit.