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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.
111

Estudo do controle de potências ativa e reativa de geradores de indução duplamente alimentados com aplicação na geração eólica / Active and reative power control of doubly-fed induction generators for wind energy applications

Trindade, Filipe Sarmento, 1987 07 November 2013 (has links)
Orientadores: Ernesto Ruppert Filho, Alfeu Joãozinho Sguarezi Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-23T13:09:28Z (GMT). No. of bitstreams: 1 Trindade_FilipeSarmento_M.pdf: 4372801 bytes, checksum: 51cf6a93426e65669c049bef356ed0a2 (MD5) Previous issue date: 2013 / Resumo: Nas últimas décadas, a crescente necessidade de novas fontes limpas e renováveis de energia elétrica provocou um grande interesse por meios alternativos às usinas elétricas convencionais. Entre eles, o aproveitamento da energia eólica. Nesse contexto, o gerador de indução de rotor bobinado tem sido bem utilizado com turbinas eólicas em todo o mundo devido à possibilidade de conexão do seu estator diretamente à rede elétrica e à possibilidade de controle das potências ativa e reativa através de conversores eletrônicos de potência conectados aos terminais do seu rotor, o que diminui a potência dos conversores para até 30% da potência nominal do gerador elétrico. Assim, a presente dissertação objetiva propor o controle das potências ativa e reativa do gerador elétrico com o uso de controladores por modos deslizantes utilizando a técnica de orientação de campo pelo fluxo do estator para realizar o controle independente dessas potências. Primeiramente, compara-se o desempenho do controlador proposto com o tradicional controle de potências por controladores PI, através de simulações computacionais da conexão do gerador à rede elétrica através de duas topologias de conversores: com apenas os terminais do estator conectados à rede elétrica e com os terminais do rotor também conectados através de conversores em anti-paralelo (back-to-back). Finalmente, o controlador por modos deslizantes foi implementado fisicamente em uma bancada experimental com apenas os terminais do estator do gerador conectados à rede elétrica para comprovação da proposta / Abstract: In the last decades, the increasing need for new clean and renewable sources of electric energy caused a great interest in alternative means to conventional power plants. Among them, the use of wind energy. In this context, the doubly-fed induction generator has been widely used with wind turbines worldwide due to the possibility of connecting its stator terminals directly to the electric power grid and its active and reactive power control possibility through electric power converters connected to its rotor terminals, which reduce the converters power capacity for up to 30% of the generator rated power. Thus, this dissertation aims to propose the generator active and reactive power control using sliding mode controllers using field-oriented control to perform independent power control. First, the performance of the proposed controller with the traditional PI power control controllers is compared through computer simulations connecting the generator to the electric grid through two converter topologies: with only the stator terminals connected to the grid and with the rotor terminals also connected to the grid through a back-to-back converter. Finally, the sliding mode controller was implemented on a laboratory assembly with only the generator stator terminals connected to the grid to prove the proposal / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica
112

Využití biomasy pro získávání elektřiny v ostrovních provozech / Biomass for power plants in the off-grid operation

Roule, Jaroslav January 2013 (has links)
The thesis discusses the use of biomass for electricity island operation. The first chapter explains the concept of biomass and its distribution. It also shows the potential and availability of biomass. The second chapter describes the transformation of biomass into a suitable fuel form. The third to fifth chapter describes the conversion of biomass as a fuel into electrical energy through combustion, Stirling and steam engine. In these chapters there are brought the following parameters and prices of these motors and single-phase and three-phase alternators that can be connected to these engines. Other chapters describe the production of electricity in line with consumption, where the cost per hour to run engines for the various types of fuel and price of the electricity produced in kilowatt hours is calculated. In the last chapter of the thesis there is described the possibility of accumulation of electrical energy.

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