Seleme Isaac Seleme Júnior

A grid-connected photovoltaic system with a maximum power point tracker using passivity-based control applied in a boost converter

The power generated by a solar photovoltaic panel is strongly dependent on climate conditions. For this reason, a grid-connected system needs a good response for variations in the solar irradiance and temperature. A non-linear control technique which has a good rejection of disturbances is the passivity-based control. This work presents the application of the passivity-based control in a maximum power tracker boost converter for a grid-connected photovoltaic system. The fast response of the control allows a better use of the photovoltaic array energy, increasing the efficiency of the system, and ensuring stability for all operation range.

Passivity-based control of PFC boost converter with high-level programming

This paper presents a procedure for high-level programming of a microcontroller using passivity-based control implemented in PFC (Power Factor Correction) boost converters. This is a non-conventional approach, where libraries are used to directly interface with the Texass DSP 2812. Initially, the block diagrams that contain the control equations are constructed. Then, the codes are generated automatically. The advantages provided by the proposed method are: economy of development cycle time, easy understanding of the control process and programming, standardization and concurrent simulation. The other contribution of the paper refers to the development of a regulated source with high power factor and low THD using a boost converter controlled via passivity-based method. The approach based on passivity has been studied recently due to clear advantages in view of disturbances in the operation conditions of the system. The purpose of this technique is to improve the converter efficiency in applications of low and medium power, and improve the quality of the energy in the grid. Finally, in a new and satisfactory way, this nonlinear control technique has been validated experimentally for boost converters.

Methodology for the design of a stand-alone photovoltaic power supply

Resumen es: Este trabajo presenta una completa metodologia para el diseno de un sistema fotovoltaico autonomo que maximiza el uso de la energia solar. El metodo prop...

On the Redundancy Strategies of Modular Multilevel Converters

The modular multilevel converters (MMCs) have become an attractive topology in recent years. The MMC has been employed in several applications as HVdc, energy storage, renewable energy, electrical drives, and static synchronous compensators (STATCOMs). One advantage of MMC-based topologies is the inherited fault-tolerant operation associated with the high number of submodules (SMs). This work proposes the study of four redundancy strategies, which can be employed in modular multilevel converters: standard redundancy, redundancy strategy based on additional submodules (RAS), redundancy strategy based on additional submodules optimized (RASO), and redundancy strategy based on spare submodules. These strategies are compared through a case study of a 15 MVA MMC STATCOM. A new approach for the SM capacitance design is proposed, including the effect of the negative sequence current in the converter storage energy variations. The comparisons of the redundancy strategies are accomplished based on dynamic behavior, capacitor voltage balancing, control complexity, and power losses. Finally, the advantages and drawbacks of each redundancy strategy are presented.

INVESTIGAÇÃO, SIMULAÇÃO E DIAGNÓSTICOS SOBRE O CONTROLE DE ACIONAMENTO DE UMA BOBINADEIRA DE AÇO INOXIDÁVEL

Esse trabalho consiste no estudo investigativo e de simulacao do controle analogico de velocidade, com limitacao da corrente do motor de acionamento da bobinadeira de uma linha de preparacao de tira de aco.Estuda-se o controle de velocidade do motor c.c., alimentado na armadura por um conversor c.a./c.c., com limitacao da corrente e de sua derivada. Utiliza-se fundamentos de tecnicas de modelagem de sistemas dinâmicos, processamento digital de sinais e de sintonia de malhas de controle com auxilio dos softwares MATLAB, PSPICE e Powersim-PSIM. A descricao do sistema, as medicoes reais, as simulacoes e a proposta de melhorias do controlador de velocidade tangencial utilizando a tecnica classica de controle empregado em eletronica analogica sao apresentadas em capitulos separados.Apesar de se tratar de tecnologia antiga, sendo amplamente empregada na industria mundial, relativamente escassos estudos foram ate entao realizados no que tange ao desempenho da tecnica classica de controle para linha de bobinadeira de aco inoxidavel. Simulacoes utilizando dados do processo real mostraram que um re-ajuste dos parâmetros do controlador pode ser eficaz em melhorar o desempenho do sistema no que se refere a robustez, estabilidade e tempo de resposta do sistema de controle frente a disturbios dos parâmetros internos do controlador, presenca de perturbacoes externas, variacoes de carga do motor e de mudancas de sinal de referencia.

Passivity-based control of boost converters using PLL

In the context that involves low and medium powers, boost-type converters have high performance and is therefore strongly recommended to work in regulated sources. However, without adequate control such converters eventually provide high levels of THD (Total Harmonic Distortion) and low power factor (pf). In this way, different authors validated the passivity-based control (PBC) applied to static converters. However, through these studies it was observed that the quality of results is associated with the input signal voltage. Thus, the insertion of the PLL (Phase-Locked Loop) is justified by the poor quality of networks in general. That is usually the power supply voltages are not purely sinusoidal and have very harmonic content. Thus, lower THD levels can be obtained by adding the PLL for imposing a sinusoidal reference signal to the input voltage.