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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.
1

Contribui??es ? estrat?gia de controle sem detec??o de harm?nicos aplicada a um filtro ativo de pot?ncia paralelo

Sousa, Raphaell Maciel de 24 November 2014 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-02-03T20:53:54Z No. of bitstreams: 1 RaphaellMacielDeSousa_TESE.pdf: 6489062 bytes, checksum: ad0b83d06c244d254f4775bacae900af (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-02-04T19:25:01Z (GMT) No. of bitstreams: 1 RaphaellMacielDeSousa_TESE.pdf: 6489062 bytes, checksum: ad0b83d06c244d254f4775bacae900af (MD5) / Made available in DSpace on 2016-02-04T19:25:01Z (GMT). No. of bitstreams: 1 RaphaellMacielDeSousa_TESE.pdf: 6489062 bytes, checksum: ad0b83d06c244d254f4775bacae900af (MD5) Previous issue date: 2014-11-24 / Os esquemas de controle convencionais aplicados em Filtros Ativos de Pot?ncia Paralelos (FAPPs) utilizam extra??o de ham?nicos, de modo que o desempenho da compensa??o depende da velocidade e precis?o com que os componentes harm?nicos da carga n?o linear s?o identificados. O FAPP pode ser implementado sem o uso de extratores de harm?nicos. Neste caso, a compensa??o dos componentes harm?nicos ? obtida a partir do balan?o de pot?ncia do sistema. O desempenho da compensa??o no caso em que o balan?o de pot?ncia ? utilizado depende da velocidade com que o sistema entra em estado de equil?brio. Neste caso, as correntes de fase s?o indiretamente reguladas por um controlador de dupla sequ?ncia (Double sequence controller - DSC) com dois graus de liberdade, cujo o princ?pio do modelo interno (internal mode principle - IMP) ? utilizado para evitar transforma??es de coordenadas e garantir erro nulo em regime permanente. Adicionalmente o DSC apresenta robustez quando o FAPP opera sob condi??es de desbalanceamento. Al?m disso, o FAPP implementado sem esquemas de detec??o compensam simultaneamente harm?ncos e reativos da carga. Suas capacidades de compensa??o, entretanto, s?o limitadas pela pot?ncia dispon?vel no conversor do FAPP. Tal restri??o pode ser minimizada se o n?vel de pot?ncia reativa compensada for flexibilizado. Um esquema de estima??o que determina as correntes do filtro ? introduzido para conferir flexibilidade na compensa??o de reativos da carga. Resultados experimentais s?o apresentados para demonstrar o desempenho do sistema proposto. / The conventional control schemes applied to Shunt Active Power Filters (SAPF) are Harmonic extractor-based strategies (HEBSs) because their effectiveness depends on how quickly and accurately the harmonic components of the nonlinear loads are identified. The SAPF can be also implemented without the use of the load harmonic extractors. In this case, the harmonic compensating term is obtained from the system active power balance. These systems can be considered as balanced-energy-based schemes (BEBSs) and their performance depends on how fast the system reaches the equilibrium state. In this case, the phase currents of the power grid are indirectly regulated by double sequence controllers with two degrees of freedom, where the internal model principle is employed to avoid reference frame transformation. Additionally the DSC controller presents robustness when the SAPF is operating under unbalanced conditions. Furthermore, SAPF implemented without harmonic detection schemes compensate simultaneously harmonic distortion and reactive power of the load. Their compensation capabilities, however, are limited by the SAPF power converter rating. Such a restriction can be minimized if the level of the reactive power correction is managed. In this work an estimation scheme for determining the filter currents is introduced to manage the compensation of reactive power. Experimental results are shown for demonstrating the performance of the proposed SAPF system.
2

Projeto em FPGA de um controlador unificado para corre??o de fator de pot?ncia em retificadores boost bidirecionais monof?sicos

Soares, Antonio Wallace Antunes 18 December 2013 (has links)
Made available in DSpace on 2014-12-17T14:56:18Z (GMT). No. of bitstreams: 1 AntonioWAS_DISSERT.pdf: 2078440 bytes, checksum: 8f0b0683ae325a95be82dafa64af1734 (MD5) Previous issue date: 2013-12-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The use of Field Programmable Gate Array (FPGA) for development of digital control strategies for power electronics applications has aroused a growing interest of many researchers. This interest is due to the great advantages offered by FPGA, which include: lower design effort, high performance and highly flexible prototyping. This work proposes the development and implementation of an unified one-cycle controller for boost CFP rectifier based on FPGA. This controller can be applied to a total of twelve converters, six inverters and six rectifiers defined by four single phase VSI topologies and three voltage modulation types. The topologies considered in this work are: full-bridge, interleaved full-bridge, half-bridge and interleaved half-bridge. While modulations are classified in bipolar voltage modulation (BVM), unipolar voltage modulation (UVM) and clamped voltage modulation (CVM). The proposed project is developed and prototyped using tools Matlab/Simulink? together with the DSP Builder library provided by Altera?. The proposed controller was validated with simulation and experimental results / A utiliza??o de Field Programmable Gate Array (FPGA) para o desenvolvimento de estrat?gias de controle digital para aplica??es em eletr?nica de pot?ncia tem despertado um crescente interesse entre muitos pesquisadores. Tal interesse se deve as grandes vantagens apresentadas pelo FPGA, que incluem: menor esfor?o de projeto, alto desempenho e grande flexibilidade de prototipagem. Este trabalho prop?e o desenvolvimento e implementa??o de um controlador unificado, mediante o uso de FPGA, utilizando a t?cnica de controle de um ciclo (One-Cycle Control Technique) para corre??o de fator de pot?ncia com retificadores boost. Este controlador pode ser aplicado a um total de doze conversores, sendo seis inversores e seis retificadores, definidos pela topologia e pelo tipo de modula??o de tens?o. As topologias consideradas neste trabalho s?o: ponte completa, ponte completa intercalada, meia ponte e meia ponte intercalada. Enquanto que as modula??es s?o classificadas em modula??o bipolar de tens?o (MBT), modula??o unipolar de tens?o (MUT) e modula??o com grampeamento de tens?o (MGT). O projeto ? desenvolvido e prototipado utilizando as ferramentas Matlab?/Simulink em conjunto com a biblioteca DSP Builder, disponibilizada pela Altera?. O controlador proposto ? com resultados de simula??o e experimentais

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