Desenvolvimento de conversores de potência com interface de painéis fotovoltaicos para smart homes

Dissertação de mestrado em Engenharia Eletrónica e de ComputadoresA microgeração e a utilização de veículos elétricos estão cada vez mais presentes no quotidiano e representam dois importantes fatores no caminho do desenvolvimento das smart grids e smart homes, que visam a gestão dos dispositivos eletrónicos ligados à rede elétrica ou à habitação. Assim sendo, a necessidade do desenvolvimento de novas tecnologias, assim como a otimização de topologias já existentes, no sentido de melhorar o carregamento de baterias dos veículos elétricos, a produção de energia a partir de fontes de energia renováveis e o melhoramento da qualidade da energia elétrica, é cada vez mais relevante. No âmbito desta dissertação pretende-se desenvolver um equipamento que surge como uma solução para a realização da interface entre veículos elétricos, painéis fotovoltaicos e a rede elétrica, além de compensar, dinamicamente, problemas de qualidade da energia elétrica. A solução tradicional utiliza dois conversores de potência para realizar a interface entre o veículo elétrico e a rede elétrica e mais dois conversores de potência para a interface da fonte de energia renovável e a rede elétrica). Esta topologia apresenta uma desvantagem no carregamento direto das baterias do veículo elétrico a partir da fonte de energia renovável, pois requer o uso de quatro conversores de potência e a rede elétrica como intermediários. Para colmatar esta desvantagem, a configuração adotada utiliza apenas um conversor CA-CC e um barramento CC comum aos dois conversores CC-CC que interligará os três conversores. Assim, obtêm-se as vantagens de utilizar apenas um conversor para realizar a interface do carregador do veículo elétrico e a fonte de energia renovável com a rede, a possibilidade de realizar o carregamento das baterias diretamente dos painéis fotovoltaicos, sem usar a rede como intermediário, e ainda a contribuição para a melhoria dos problemas de qualidade de energia. Nesta dissertação, foi desenvolvido um conversor CA-CC (em colaboração com outra dissertação), o mais reduzido possível (usando SiC - Silicon Carbide, como semicondutores controlados), variando assim as suas caraterísticas de forma a se obter a redução de tamanho e a realizar a interface com os outros dois conversores de potência (CC-CC). Após um estudo cuidado do estado da arte, foi desenvolvido um modelo computacional em PSIM e foi desenvolvido um protótipo laboratorial (conversor CA-CC e CC-CC), onde o conversor CC-CC realiza a interface com a fonte de energia renovável (com algoritmo de controlo de maximum power point tracker (MPPT)). Com recurso ao sistema desenvolvido foram obtidos resultados experimentais que comprovam a solução adotada.Microgeneration and the use of electric vehicles are increasingly present in our daily lives and they represent two major factors in the development of smart grids and smart homes, which aim to manage electronic devices connected to the power grid or to the house. Therefore, the need to develop new technologies as well as improving the existing ones in order to improve battery charging of electric vehicles, the production of energy from renewable power sources and the improvement of energy quality is increasingly relevant. This dissertation intends to develop an equipment that emerges as a solution for the interface between electric vehicles, photovoltaic panels and the power grid as it also dynamically compensates for problems of power quality. The traditional solution uses two power converters to interface between the electric vehicle and the power grid (one ac/dc converter and another dc/dc converter) and two more power converters for the renewable power source (one ac/dc converter and another dc/dc converter). This traditional topology has a disadvantage in the direct charging of the electric vehicle batteries from the renewable energy source as it requires the use of four power converters and the power grid as intermediates. To overcome this drawback, the adopted configuration uses only one ac/dc converter and one common dc link to interface the two dc/dc converters with the ac/dc converter. This gives the advantages of using only one converter to interface the electric vehicle charger and the renewable power source with the power grid. It also allows the ability to charge the batteries directly from the photovoltaic panels without using the power grid as an intermediary further contributing to improve issues related to the quality of power. Through this dissertation, when combined with another dissertation, an AC/DC converter, compacted as much as possible will be developed, thus varying its characteristics in order to obtain the size reduction. This will interface with the other two power converters (dc/dc). Posteriorly and individually, a dc/dc converter will be developed that will interface with the renewable power source, where a maximum power point tracker (MPPT) control algorithm is applied in order to extract as much power as possible from the photovoltaic panel.Este trabalho de dissertação está enquadrado no projeto de IC&DT “newERA4GRIDs – New Generation of Unified Power Conditioner with Advanced Control, Integrating Electric Mobility, Renewables, and Active Filtering Capabilities for the Power Grid Improvement”, financiado pela Fundação para a Ciência e Tecnologia, com a referência PTDC/EEI‑EEE/30283/2017.Este trabalho de dissertação está enquadrado no projeto de IC&DT “DAIPESEV – Development of Advanced Integrated Power Electronic Systems for Electric Vehicles”, financiado pela Fundação para a Ciência e Tecnologia, com a referência PTDC/EEI EEE/30382/2017

A novel three-phase multilevel AC-DC converter operating as a shunt active power filter: Validation considering an industrial environment

Power quality problems are an issue that requires, each more, particular attention, among others, to prevent equipment failure and improve efficiency. In this context, this paper presents a novel three-phase four-wire multilevel AC-DC converter operating as a shunt active power filter aiming to reduce the current harmonic distortion, low power factor, and current unbalances, which are introduced by the non-linear loads. The proposed topology comprises a total of six full bridges, where every two full bridges are arranged in a cascade structure and connected to one of the phases of the power grid. Both the proposed topology, as well as the applied control algorithm, are validated using computer simulations considering the most relevant conditions of operation in an industrial environment. The obtained results validate the proposed three-phase multilevel converter when operating as a shunt active power filter, showing that the power quality problems presented in the currents are compensated and the converter operates with the multilevel characteristic for all the conditions of operation

Computer studies of the operation of a Three Phase Four Wire Shunt Active Power Filter applied to the Industry

EAI SESC 2021 - 3rd EAI International Conference on Sustainable Energy for Smart Cities (online event), November 24 – 26, 2021 - Portugal.As the industry progresses, power quality problems become more and more rele-vant. The increase of non linear loads in industries, leads to higher current har-monic distortion and low power factor. In order to mitigate these problems, this paper validates a shunt active power filter (SAPF). The adopted topolo-gy and its control algorithm are analyzed through computer simulations consider-ing real industrial load models, which were elaborated from data collected in power quality analyzers that were connected to different points of an industry. The results achieved validate the correct operation of the applied SAPF, as well as it presents the improvements obtained of the total current distortion and neutral current.This work is supported by: European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Pro-gramme (COMPETE 2020) [Project nº 39479; Funding Reference: POCI-01-0247-FEDER-39479]

Parallel association of power semiconductors: an experimental evaluation with IGBTs and MOSFETs

This paper presents a study on the parallel association of power semiconductors. The main purpose of this paper is to demonstrate that the parallel association of lower rated power semiconductors can be more advantageous than the use of a single higher rated power semiconductor, both economically and in terms of dynamic performance, i.e., switching behavior and semiconductor temperature. In this context, two different power semiconductor technologies were tested: (1) Insulated gate bipolar transistors (IGBTs); and (2) Metal oxide semiconductor field effect transistors (MOSFETs). For each technology, the adopted methodology consisted of verifying the dynamic performance of a single higher rated power semiconductor, comparing it with the dynamic performance of a set of five parallel-connected lower rated power semiconductors, focusing on the current sharing between the devices. The obtained experimental results demonstrate that the parallel connection of lower rated power semiconductors can be advantageous over the use of a single higher rated power semiconductor above certain power levels, offering better switching characteristics and lower cost.INCT-EN -Instituto Nacional de Ciência e Tecnologia para Excitotoxicidade e Neuroproteção (SFRH/BD/134353/2017