This thesis presents a new DC/AC inverter circuit which is based on a switched-capacitor circuit topology with reduced components (power switch and capacitor) count for low power applications. The proposed circuit has distinct features of both voltage boost-up and near sinusoidal (multi-level/staircase) AC output voltage. The main idea is to utilise a simple circuit technique called resonant-based Double Switch Single Capacitor Switched-Capacitor (DSSC SCC) with variable duty cycle Pulse Width Modulation (PWM) control technique in such a way that multi-level voltage can be realised across a capacitor. In order to show the superiority of the applied technique, comparisons with other techniques/circuits configurations are presented. The circuit technique can significantly reduce the number of multiple stages of switched-capacitor circuit cells of the recent switched-capacitor multi-level inverter topology. The proposed inverter (with integrated DSSC SCC technique) can generate a line-frequency with 13-levels near sinusoidal AC output voltage with low total harmonics distortion. The output voltage can be achieved with the least number of components use and only a single DC source is used as an input. The proposed inverter topology is also reviewed against other inverter-based switched-capacitor circuit topology and the well-known multi-level inverter topology. The proposed inverter has shown a tremendous reduction in the total harmonics distortion and circuit component count in comparison with the recent Switched-Capacitor Boost multi-level inverter and the classical Cascaded H-Bridge multi-level inverter. Mathematical analysis shows the design of the proposed inverter and PSPICE simulation result to verify the design is also presented. The practical experiment implementation of the proposed system is presented and proves the correct operation of the proposed inverter topology by showing consistency between simulation results and practical results.

Com o déficit de energia que atualmente preocupa o setor elétrico brasileiro, ameaçando os consumidores com a possibilidade de novos racionamentos, surge a perspectiva de aumento de produção de energia, através da criação de usinas eólicas para suprir essa demanda. Entretanto, esta forma de geração, sabidamente, provoca distorções na qualidade de energia fornecida, principalmente quanto à geração de harmônicas, que acabam por interferir diretamente nas cargas podendo provocar danos a equipamentos e instalações. Por esse motivo, este trabalho visa analisar a contribuição desse tipo de geração no sistema elétrico e discutir, com base em estudos experimentais realizados em modelos de aerogeradores e diretamente em unidades geradoras instaladas em plantas de geração eólica, as perturbações harmônicas geradas pelo controle de tensão e frequência do sistema. A metodologia utilizada será a de medição das distorções harmônicas, através de analisadores de qualidade de energia, instalados primeiramente em modelos laboratoriais dos principais tipos de aerogeradores existentes no mercado, medindo as perturbações em diversas situações de carga, obedecendo ao estabelecido na norma NBR-IEC- 61400-21/2010 Medição e Avaliação da Qualidade de Energia de Aerogeradores Conectados a Rede. / With the energy deficit that currently worries the Brazilian electric sector, threatening consumers with the possibility of further rationing comes the prospect of increased energy production through the creation of wind farms to meet this demand. However, this form of generation is known to distort the quality of power supplied, especially as the generation of harmonics, which ultimately interfere directly in the loads can cause damage to equipment and facilities. Therefore, this study aims to analyze the contribution of this type of generation on the electrical system and discuss, based on experimental studies in directly generating units installed in wind generation plants, disturbances generated by harmonic voltage and frequency control system. The methodology will be the measurement of harmonic distortion through power quality analyzers, installed primarily in laboratory models of the main types of wind turbines on the market, measuring disturbances in various loading conditions, obeying the established standard NBR-IEC-61400-21/2010 - Measurement and Evaluation of Power Quality of Wind Turbines Connected Network.

Com o déficit de energia que atualmente preocupa o setor elétrico brasileiro, ameaçando os consumidores com a possibilidade de novos racionamentos, surge a perspectiva de aumento de produção de energia, através da criação de usinas eólicas para suprir essa demanda. Entretanto, esta forma de geração, sabidamente, provoca distorções na qualidade de energia fornecida, principalmente quanto à geração de harmônicas, que acabam por interferir diretamente nas cargas podendo provocar danos a equipamentos e instalações. Por esse motivo, este trabalho visa analisar a contribuição desse tipo de geração no sistema elétrico e discutir, com base em estudos experimentais realizados em modelos de aerogeradores e diretamente em unidades geradoras instaladas em plantas de geração eólica, as perturbações harmônicas geradas pelo controle de tensão e frequência do sistema. A metodologia utilizada será a de medição das distorções harmônicas, através de analisadores de qualidade de energia, instalados primeiramente em modelos laboratoriais dos principais tipos de aerogeradores existentes no mercado, medindo as perturbações em diversas situações de carga, obedecendo ao estabelecido na norma NBR-IEC- 61400-21/2010 Medição e Avaliação da Qualidade de Energia de Aerogeradores Conectados a Rede. / With the energy deficit that currently worries the Brazilian electric sector, threatening consumers with the possibility of further rationing comes the prospect of increased energy production through the creation of wind farms to meet this demand. However, this form of generation is known to distort the quality of power supplied, especially as the generation of harmonics, which ultimately interfere directly in the loads can cause damage to equipment and facilities. Therefore, this study aims to analyze the contribution of this type of generation on the electrical system and discuss, based on experimental studies in directly generating units installed in wind generation plants, disturbances generated by harmonic voltage and frequency control system. The methodology will be the measurement of harmonic distortion through power quality analyzers, installed primarily in laboratory models of the main types of wind turbines on the market, measuring disturbances in various loading conditions, obeying the established standard NBR-IEC-61400-21/2010 - Measurement and Evaluation of Power Quality of Wind Turbines Connected Network.