La utilización de filtros activos paralelo mejora la eficiencia del suministro eléctrico mediante la modificación de las características de la forma de onda de las corrientes de línea. Trabajos de investigación anteriores destacan la complicada estructura de los controladores empleados en este tipo de soluciones y su sensibilidad a la distorsión de la onda de tensión en el punto donde se realiza su conexión. El objetivo fundamental de esta tesis es el desarrollo de un controlador para filtros activos de potencia tolerante a desequilibrios de tensión, huecos de tensión y armónicos de tensión. Objetivo secundario de este trabajo es el diseño de los algoritmos necesarios para el control de un filtro activo de potencia paralelo polifásico mediante una tarjeta basada en un procesador digital de señal. / Shunt active power filters (APF) modify the phase current waveform characteristics, which allow to increase the efficiency of electrical power grids. Previous research works establish the complex structure of controllers applied to APFs and their sensibility to voltage waveform disturbances.The aim of this thesis is the developing of a controller for shunt active power filters with tolerance to voltage unbalances, voltage dips and voltage harmonics. The proposed controller, implemented on a DSP target board, will be tested on a three-phase active power filter.

Multifunctional voltage source converters (VSCs) are desired for shipboard power systems. The opportunity to extend the functionality of a particular VSC on demand, combined with power system reconfiguration strategies may provide desired redundancy to back up power electronic converters that might be destroyed as a result of a battle damage or material casualty. The space for power electronics may be downsized if the VSCs are capable of performing multiple functions. In addition, the flexibility of the energy management can be enhanced in shipboard power systems if a single VSC can perform multiple functions. The functionality of a VSC in many cases is restricted to a single task or set of tasks by its control architecture. Despite the great number of different control strategies suggested for VSCs, nearly all use similar methods for generation of the reference signals. These methods generally depend upon the use of filters to extract reference signals for the components that are to be injected into or drawn from the system. These methods of control are not flexible. The main objective of the dissertation is the development of a flexible reference signal generator for VSCs that allows online maximization of its possible functions. Furthermore, the switching frequency of a VSC is generally above 10 kHz for many applications, and carries a significant amount of high frequency noise. This necessitates the use of EMI filters, which carry an extra cost and increase the overall bulk of the power electronics. This may not be acceptable for shipboard power systems, where the space and weight requirements are usually stringent. Thus, in addition to investigation of various reference signal generator (RSG) strategies for VSCs, alternative solutions to attenuate EMI levels in the shipboard power system environment are explored.

Significant advances in modern ac/ac power converter technologies and demands of industries have reached beyond standard ac/ac power converters with voltage-source inverters fed from diode rectifiers. Power electronics converters have been matured to stages toward compact realization, increased high-power handling capability, and improving utility interface. Modern ac/ac power converter topologies with various control strategies have been introduced for the further improvements, such as matrix converters, current-fed converters, PWM rectifiers, and active power filters. In this dissertation, several new converter topologies are proposed in conjunction with developed control schemes based on the modern ac/ac converters which enhance performance and solve the drawbacks of conventional converters. In this study, a new fault-tolerant PWM strategy is first proposed for matrix converters. The added fault-tolerant scheme would strengthen the matrix converter technology for aerospace and military applications. A modulation strategy is developed to reshape output currents for continuous operation, against fault occurrence in matrix converter drives. This study designs a hybrid, high-performance ac/ac power converter for high power applications, based on a high-power load commutated inverter and a mediumpower voltage source inverter. Natural commutation of the load commutated inverter is actively controlled by the voltage source inverter. In addition, the developed hybrid system ensures sinusoidal output current/voltage waveforms and fast dynamic response in high power areas. A new topology and control scheme for a six-step current source inverter is proposed. The proposed topology utilizes a small voltage source inverter, to turn off main thyristor switches, transfer reactive load energy, and limit peak voltages across loads. The proposed topology maximizes benefits of the constituent converters: highpower handling capability of large thyristor-based current source inverters as well as fast and easy control of small voltage source inverters. This study analyzes, compares, and evaluates two topologies for unity power factor and multiple ac/ac power conversions. Theoretical analyses and comparisons of the two topologies, grounded on mathematical approaches, are presented from the standpoint of converter kVA ratings, dc-link voltage requirements, switch ratings, semiconductor losses, and reactive component sizes. Analysis, simulation, and experimental results are detailed for each proposed topology.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-24T20:26:56Z No. of bitstreams: 1 pablocarlosdesiqueirafurtado.pdf: 4055605 bytes, checksum: b23cd5bfadf3eb9e69e3e5e804322231 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-25T15:21:49Z (GMT) No. of bitstreams: 1 pablocarlosdesiqueirafurtado.pdf: 4055605 bytes, checksum: b23cd5bfadf3eb9e69e3e5e804322231 (MD5) / Made available in DSpace on 2017-04-25T15:21:49Z (GMT). No. of bitstreams: 1 pablocarlosdesiqueirafurtado.pdf: 4055605 bytes, checksum: b23cd5bfadf3eb9e69e3e5e804322231 (MD5) Previous issue date: 2014-06-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Esta dissertação apresenta uma estratégia para controlar um filtro ativo de potência (FAP) paralelo bifásico a três fios. A aplicação desse FAP pode ser implementada como uma funcionalidade extra do conversor fonte de tensão do sistema de propulsão de veículos elétricos (VE), o que seria útil para compensar instalações elétricas residenciais e comerciais com fornecimento de energia bifásico a três fios. Apresenta-se o princípio de funcionamento do FAP bifásico e é tratada sua modelagem matemática. É feita uma revisão dos conceitos de potências instantâneas p e q em sistemas monofásicos, a chamada teoria p–q monofásica. É mostrada ainda a interpretação dessas grandezas e sua relação com as potências ativa e reativa convencionais. Em seguida, são feitas adaptações na implementação dessa teoria. A principal adaptação está na forma de implementar as transformações αβ monofásicas. Com essas adaptações, a teoria p–q modificada é utilizada para descrever o algoritmo de controle desenvolvido para o FAP bifásico. A estratégia de compensação adotada consiste na compensação de todas as componentes harmônicas de corrente, da potência reativa e na equalização das correntes nas fases envolvidas. São apresentados resultados obtidos em estudos de simulação da operação do FAP bifásico em regime permanente e sob transitórios das cargas. O trabalho mostra ainda alguns resultados experimentais do FAP em operação. Conclui-se que os resultados obtidos validam o princípio de operação do FAP bifásico e a estratégia de controle proposta. / This thesis presents an strategy to control a two–phase, three-wire shunt active power filter (APF). This APF can be implemented as an extra functionality of the embedded voltage source converter in the propulsion system of an electric vehicle (EV). This application would be useful in the compensation of residential and commercial electrical installations fed by a two–phase three–wire grid connection. The working principle of shunt two-phase APF is presented and its mathematical models are also treated. Concepts of the instantaneous powers p and q, called single-phase p–q theory, are reviewed. The relationship between these quantities and the conventional active and reactive powers is discussed. Then, some adaptations are done in the implementation of such theory. The main one is related to the implementation method of singlephase αβ transformations. After these adaptations, the modified p–q theory is used to described the developed algorithm to control the two–phase APF. The adopted control strategy consists of compensating all current harmonics and reactive power, as well as equalizing currents in involved phases. Simulation results are presented to show the APF operation in steady-state and under load changes. Yet, some experimental results are presented to show the APF in operation. The obtained results validate the presented working principle and the control strategy proposed in this thesis.