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  • 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.
11

Modelagem e controle de gerador de indução duplamente alimentado para estudo de sistema de geração eólica / Modeling and control of doubly-fed induction generator for the study of wind generation system

Rocha, Marco Aurélio 27 March 2018 (has links)
Submitted by Marco Aurelio Rocha (rochamarco.eng@gmail.com) on 2018-04-19T12:44:32Z No. of bitstreams: 1 Dissertação_Marco_Rocha_FINAL.pdf: 4334808 bytes, checksum: bcc84d54c373bafcb2362766219becac (MD5) / Approved for entry into archive by Minervina Teixeira Lopes null (vina_lopes@bauru.unesp.br) on 2018-04-19T18:51:03Z (GMT) No. of bitstreams: 1 rocha_ma_me_bauru.pdf: 4334226 bytes, checksum: d2b0086eaa88031ec113f8e0a415c74c (MD5) / Made available in DSpace on 2018-04-19T18:51:03Z (GMT). No. of bitstreams: 1 rocha_ma_me_bauru.pdf: 4334226 bytes, checksum: d2b0086eaa88031ec113f8e0a415c74c (MD5) Previous issue date: 2018-03-27 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Esta dissertação apresenta a análise, modelagem e controle vetorial de um sistema de geração eólica tendo um gerador de indução duplamente alimentado como máquina primária e equipado com um conversor back-to-back para gerenciamento da potência entregue ou absorvida da rede elétrica, independentemente do tipo de carga instalada, por meio de compensação de reativos e filtragem ativa das correntes da rede. Para atingir este objetivo, a modelagem do sistema, bem como o projeto dos controladores foram desenvolvidos no ambiente de simulação Matlab®/Simulink®, em que o controle do conversor do lado do rotor realiza a regulação do torque e o controle de potência ativa e reativa, enquanto que o controle do conversor do lado da rede tem a função de manter a tensão do link-CC constante e produzir fator de potência unitário, compensando reativos oriundos do sistema de geração eólica e da carga instalada e atuando como um filtro ativo de potência, melhorando o índice de distorção harmônica da corrente da rede. Além disso, controladores proporcionais-ressonantes foram utilizados a fim de mitigar harmônicos gerados pelo conversor atuando no modo retificador. Também foi realizado o controle do ângulo de passo das pás da turbina, com a finalidade de obter a máxima potência para qualquer velocidade do vento. Os resultados obtidos permitiram avaliar o desempenho dos controladores, de modo que o fator de potência foi mantido unitário para variações abruptas de carga. Tem-se compensação harmônica para cargas não-lineares sendo extraída e gerada a máxima potência oriunda do vento. / This dissertation presents the analysis, modeling and vector control of a wind power system with a doubly-fed induction generator as a primary machine and equipped whit a back-to-back converter to manage power delivered to or absorbed from the grid, independently of the installed load type, through reactive compensation and active filtering of grid currents. To achieve this goal, the system modelling and the controller design was developed in the Matlab®/Simulink® software, where the rotor-side converter control regulates torque and control active and reactive power. The grid-side converter control has the function of maintaining the DC link voltage constant and produce unit power factor, compensating reactive power from the wind generation system and the installed load and acting as an active power filter, which improves the total harmonic distortion of the grid current. In addition, proportional-resonant controller was used to mitigate harmonics generated by the converter acting in the rectifier mode. The pitch angle controller also was made in order to obtain the maximum power for any wind speed. The results obtained allowed to evaluate the performance of the controllers, so that the power factor was unit for abrupt loads variation, there was harmonic compensation for nonlinear loads and the maximum power from the wind was extracted and generated. / CNPq: 13.2999/2016-1
12

Pre-study of optical LED units for shunting signals / Förstudie för optisk LED-enhet för dvärgsignaler

Adolfsson, Tobias, Dellenby, Axel January 2021 (has links)
Alstom wanted to investigate the possibility of adapting its light emitting diode (LED) technology for shunting signals in train traffic. The LED technology uses 50V, but Alstom wants to adapt it for 12V. The LED technology is energy efficient but needs to be adapted for existing signal interlocking by drawing a higher current. This meant that the possibility of reactive power compensation was investigated to obtain lower thermal dissipation in dwarf signal. The essay presents a couple of possible solutions. One of the solutions is to raise the voltage by using a booster converter to use the existing 50V LED unit. Capacitors were reviewed to be used in reactive power compensation to increase current supply. One of the solutions then became a capacitor bank. Simulations indicated that a booster converter and a capacitor bank can be used to adapt the circuit. However, some modifications must be made. / Alstom ville undersöka möjligheten att anpassa sin lysdiodsteknik för dvärgsignaler i tågtrafiken. Lysdiodstekniken använder 50V men Alstom vill anpassa den för 12V. Lysdiodtekniken är strömsnål och behöver anpassas för befintliga signalställverk genom att dra en högre ström. Detta innebar att möjligheten för reaktiv kompensering undersöktes för att få en låg värmeutvecklingen i dvärgsignalen. I uppsatsen presenteras ett par möjliga lösningar. En av lösningarna för spänningen är en step-up omvandlare för att nyttja 50Vs enheten. Det gjordes också en genomgång av kondensatorer för att nyttjas i reaktivkompensering för att öka strömförbrukningen. En av lösningarna blev då ett kondensatorbatteri. Det kunde konstateras med matematisk simulering att step-up omvandlare och ett kondensatorbatteri kan användas för att anpassa kretsen dock måste vissa modifieringar utföras.

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