Circuitos amortecedores de tensão aplicados em conversores de potência baseados em redes de impedância do tipo Quasi Fonte-Y
Carregando...
Arquivos
Data
2023-06-01
Autores
Diver, Rodrigo de Paula
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Nas últimas décadas a integração de fontes de energias renováveis à rede vem passando por uma grande evolução, em especial nos sistemas de geração distribuídos baseados em energia fotovoltaica. Este cenário incentivou o desenvolvimento de novas topologias de conversores de potência adaptadas às características operacionais inerentes das fontes renováveis atendidas. Neste contexto, os conversores de potência baseados em redes de impedância apresentam destaque, devido a características operacionais relacionadas com a sua capacidade de lidar com shoot-through em braços de inversores e de obtenção de elevados ganhos de tensão com menor uso de razão cíclica. Dentre as topologias de redes de impedância, as com acoplamento magnético como as da família Fonte-Y são interessantes, pois agregam um grau de flexibilidade na determinação do ponto de operação graças as relações de transformação dos indutores acoplados. No entanto, o benefício do acoplamento magnético vem acompanhado de indutâncias de dispersão que ocasionam o aumento nos esforços de tensão sobre os interruptores de potência nas comutações para o bloqueio, efeitos que podem causar danos permanentes aos dispositivos. Desta forma, circuitos amortecedores de tensão podem ser empregados para limitar os esforços dentro de valores seguros, viabilizando a operação dos conversores que empregam rede de impedância da família Fonte-Y. Por outro lado, no estado do conhecimento atual (2023), há ausência de trabalhos que apresentem orientações sobre as melhores configurações de circuitos amortecedores de tensão, acompanhadas de metodologia consistente para o projeto dos circuitos amortecedores de tensão aplicados em conversores baseados em redes de impedância da família Fonte-Y. Assim, este trabalho contribui com o estado do conhecimento explorando a aplicação de três diferentes tipos de circuitos amortecedores de tensão passivos (RC, RCD e LCD) e de circuito amortecedor ativo no conversor Quasi Fonte -Y, buscando limitar os esforços de tensão sobre os interruptores de potência. Análises comparativas foram realizadas considerando as características operacionais dos circuitos amortecedores de tensão avaliados, e desenvolvimento de metodologia de projeto é apresentada para o circuito amortecedor do tipo LCD. As metodologias de projeto propostas para os circuitos amortecedores foram avaliadas e validadas através de simulações computacionais e por meio de ensaios experimentais em protótipo, com os resultados demonstrando boa aderência entre as estimativas teóricas e o comportamento real dos circuitos, confirmando a viabilidade do uso do circuito amortecedor do tipo LCD no conversor Quasi Fonte-Y.
In recent decades, the integration of renewable energy sources into the grid has undergone a great evolution, especially in distributed generation systems based on photovoltaic energy. This scenario encouraged the development of new topologies of power converters to adapt to the inherent operating characteristics of the renewable sources. In this context, power converters based on impedance networks stand out due to operational characteristics related to their ability to deal with shoot-through in inverter arms and obtain high voltage gains with less use of the duty cycle. Among the topologies of impedance networks, those with magnetic coupling such as the Y-Source family are interesting because they add a degree of flexibility in the construction of the operating point related to the transformation ratios of the coupled inductors. However, the benefit of magnetic coupling is accompanied by leakage inductances that cause an increase in voltage stresses on the power switches in switching to blocking, effects that can cause permanent damage to the devices. In this way, external voltage circuits can be used to mitigate efforts within safe values, enabling the operation of the converters using the Y-Source network. On the other hand, in the current state of knowledge (2023) there is a lack of works that presented guidelines on the best configurations of damping circuits accompanied by a consistent methodology for the design of voltage damping circuits applied in converters based on impedance networks of the Y-Source. Thus, this work contributes to the state of knowledge by exploring the application of three different types of passive voltage snubber circuits (RC, RCD and LCD) and active circuits in the Quasi Y-Source converter, aiming to make the operation of the switches with voltage stress limitation. Comparative analyzes were carried out considering the operational characteristics of the voltage snubber circuits, and the development of a design methodology is presented for the LCD-type snubber circuit. The proposed design methodologies for the snubber circuits were evaluated and validated through computational simulations and experimental prototype tests, with the results demonstrating good adherence between theoretical predictions and the actual behavior of the circuits, confirming the viability of using the LCD-type snubber in the Quasi Y-Source converter.
In recent decades, the integration of renewable energy sources into the grid has undergone a great evolution, especially in distributed generation systems based on photovoltaic energy. This scenario encouraged the development of new topologies of power converters to adapt to the inherent operating characteristics of the renewable sources. In this context, power converters based on impedance networks stand out due to operational characteristics related to their ability to deal with shoot-through in inverter arms and obtain high voltage gains with less use of the duty cycle. Among the topologies of impedance networks, those with magnetic coupling such as the Y-Source family are interesting because they add a degree of flexibility in the construction of the operating point related to the transformation ratios of the coupled inductors. However, the benefit of magnetic coupling is accompanied by leakage inductances that cause an increase in voltage stresses on the power switches in switching to blocking, effects that can cause permanent damage to the devices. In this way, external voltage circuits can be used to mitigate efforts within safe values, enabling the operation of the converters using the Y-Source network. On the other hand, in the current state of knowledge (2023) there is a lack of works that presented guidelines on the best configurations of damping circuits accompanied by a consistent methodology for the design of voltage damping circuits applied in converters based on impedance networks of the Y-Source. Thus, this work contributes to the state of knowledge by exploring the application of three different types of passive voltage snubber circuits (RC, RCD and LCD) and active circuits in the Quasi Y-Source converter, aiming to make the operation of the switches with voltage stress limitation. Comparative analyzes were carried out considering the operational characteristics of the voltage snubber circuits, and the development of a design methodology is presented for the LCD-type snubber circuit. The proposed design methodologies for the snubber circuits were evaluated and validated through computational simulations and experimental prototype tests, with the results demonstrating good adherence between theoretical predictions and the actual behavior of the circuits, confirming the viability of using the LCD-type snubber in the Quasi Y-Source converter.
Descrição
Palavras-chave
Amortecedores de Tensão, Amortecedor tipo LCD, Conversores CC-CC, Redes de Impedância, Quasi Fonte-Y, DC-DC Converters, Impedance Source, LCD-type snubber, Quasi Y-Source, Voltage Snubber