Comparação quantitativa de métodos de paralelismo de módulos fotovoltaicos com a rede elétrica para geração distribuída através de controle de conversores de potência

• Ano de defesa: 2012
• Autor(a) principal: Fabio Simim Collares
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Engenharia Elétrica; Engenharia elétrica
• Link de acesso: http://hdl.handle.net/1843/BUOS-95QFQZ

This project develops, analyzes and simulates the parallel connection between a single-phase double-stage photovoltaic system and the utility by means of current injection control techniques using Proportional Integral and Proportional Resonant controllers, and also by means of the voltage and frequency droop technique to determinate the injected power to the utility, comparing the results. Techniques to suppress the 3rd harmonic component of the current supplied to the utility, caused by the 2nd harmonic overlapped to the dc bus voltage due to the dc/ac conversion, are also presented and simulated. In addition to the usage of the traditional dc bus capacitor increasing and synchronous sampling (120 Hz) of the dc voltage techniques for such end, this project proposes two novel approaches for suppressing the 2nd / 3rd harmonic component in the single-phase double-stage PV systems: The usage of Repetitive and Resonant compensators for the harmonic rejection. The simulated results are comparatively discussed in terms of harmonic content, dynamic behavior, reliability and complexity of each method. In addition, a study and simulation of different maximum power point tracking techniques in the presence of temperature and solar intensity transients is performed. The performance of the methods is classified according to the time it takes to converge to the maximum power point in the presence of such transients, the existence or not of steady state errors, and the presence or not of oscillations around the optimized point of operation. Apart from the conventional algorithms as Perturb & Observe and Incremental Conductance, this project makes usage of the ModifiedPerturb & Observe method which consists of an improved version of the traditional one, presenting an adaptive increment. A complete study of the parallel coupling of photovoltaic systems to the utility is developed considering the modeled solar module array, the input filter, the dc/dcconverter, the dc bus, the dc/ac converter, the output filter, the utility common coupling point, local loads, measurement and sampling of the electrical parameters the converters' control, and the utility interface logics according to standard definitions. The simulation results are compared to the utility coupling standards' established limits that include features like grid disconnection, reconnection, rated voltage and frequency, harmonic content, direct current component and power factor.