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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

Inversor MultinÃvel HÃbrido SimÃtrico TrifÃsico de Cinco NÃveis Baseado na Topologias Half-Bridge/ANPC / FIVE LEVEL THREE PHASE SYMMETRICAL HYBRID MULTILEVEL INVERTER BASED ON A HALF-BRIDGE/ANPC TOPOLOGY

Ranoyca Nayana Alencar LeÃo e Silva 22 February 2013 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Este trabalho apresenta uma topologia de inversor multinÃvel hÃbrido simÃtrico trifÃsico de cinco nÃveis, concebido a partir das estruturas meia ponte e inversor com grampeamento ativo do neutro, adequado para aplicaÃÃes com alta tensÃo e alta potÃncia. SÃo apresentados os possÃveis estados de comutaÃÃo, lÃgica de acionamento, cÃlculo dos esforÃos nos semicondutores, assim como um estudo de perdas. Duas estratÃgias de modulaÃÃo sÃo selecionadas possibilitando a operaÃÃo concomitante de metade dos interruptores em baixa frequÃncia (60 Hz) e a outra em alta frequÃncia (1020 Hz), reduzindo o nÃmero de comutaÃÃes, consequentemente as perdas nos semicondutores e o conteÃdo harmÃnico da tensÃo de saÃda. Para validar a proposta, foi desenvolvido um protÃtipo com potÃncia de 7,5 kVA e tensÃo de saÃda eficaz de linha 380 V. AlÃm disso, à apresentada a implementaÃÃo de ambas as modulaÃÃes no dispositivo lÃgico programÃvel escolhido, FPGA. Os resultados experimentais da estrutura trifÃsica validam a topologia proposta. A estrutura, operando com a modulaÃÃo baseada na PD-PWM, apresentou DHT de 29,71% e WTHD de 1,93%, enquanto que a baseada na CSV-PWM apresentou DHT de 38,45% e WTHD de 7,21%. AlÃm disso, o rendimento da estrutura proposta à superior se comparado ao da topologia Half-Bridge/NPC, conforme esperado em funÃÃo das perdas na estrutura Half-Bridge/NPC serem maiores e mal distribuÃdas. / This work presents a new topology of a hybrid five-level inverter, conceived from the halfbridge and active neutral point clamped structures, suitable for high-voltage, high-power applications. The possible commutation stages, the switching drive logic, the semiconductors stresses mathematical analysis, and the losses study are presented. Two modulation techniques were selected in order to allow low-frequency (60 Hz) switches operate together with high-frequency switches (1020 Hz), reducing the number of commutations and, consequently, the overall losses and the output voltage total harmonic distortion. In order to validate the proposal, it was developed a 7.5 kVA prototype and AC line output voltage of 380 V. The digital implementation from both modulation techniques on the chosen programmable logic device FPGA is also presented. The experimental results relative to the three-phase structure validate the proposed topology. The topology, operating with the modulation based on Sinusoidal In-Phase Disposition - PWM, presented a THD of 29.71%, and WTHD of 1.93%, while the one based on the Centered Space Vector - PWM presented a THD of 38.45%, and a WTHD of 7.21%. Besides, the overall efficiency is superior when compared to the Half-Bridge/NPC topology, as expected, due to the fact that losses on this structure are higher and misdistributed.

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