Estudo e implementação de um conversor bidirecional c.c.-c.a. monofásico de dois estágios como interface entre uma nanorrede e a rede elétrica

Detalhes bibliográficos
Ano de defesa: 2014
Autor(a) principal: Aecio da Silva Bolzon
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de Minas Gerais
UFMG
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
PLL
Link de acesso: http://hdl.handle.net/1843/BUOS-9UPM25
Resumo: The increased demand for electricity and the need to diversify the national electric matrix pose challenges and opportunities for new technologies in the generation, transmission and distribution of energy. Thus, smart energy networks or Smart Grids introduces new concepts to the electrical system, as microgrids and nanogrids. The dc nanogrid presents several advantages compared to an ac nanogrid. The nanogrid interface with the power grid is performed via a bi-directional power converter which can operate with any power factor in the ac side, and can also respond to requests for demand for marketing active power. In this thesis, a study, a design and an assembly of a single phase ac-dc bi-directional converter with two stages is performed, which acts as an interface between the nanogrid dc bus and the power grid. An introductory study about the nanogrid is presented. Different transformerless bi-directional ac-dc converters topologies are presented and discussed. It is proposed the use of the NPC (Neutral Point Clamped) topology for the first stage of the converter and the synchronous rectifier topology for the second stage of the converter. The functional blocks of the converter are studied with the bias to optimize the power density. It is presented a control strategy which enables the converter to inject a sinusoidal waveform current in the power grid with low harmonic distortion and near unity power factor. With this control strategy, the converter is also able to regulate the nanogrid dc bus voltage, assuming a small ripple. A method for islanding detection is presented, which is based on the instability of an enhanced PLL (Phase Locked Loop).