Resumo-Este artigo apresenta o estudo e a implementação de um novo conversor CA-CC trifásico bidirecional de único estágio com correção de fator de potência e isolado em alta frequência. O conversor proposto é concebido utilizando-se o conceito de interleaving, e no dual active bridge (DAB) com controle phase-shift. São desenvolvidas análises teóricas baseadas no uso do modelo fundamental e utilizando-se o conceito da modulação AM DSB (Amplitude Modulation with Double Side-Band), sendo validado por simulações numéricas. Resultados experimentais obtidos com um protótipo de 1,5 kW são apresentados a fim de validar o estudo da topologia proposta.

This work proposes an isolated double conversion UPS with power factor correction using a high frequency transformer, and input voltages equal to 110V/220V. The arrangement is suitable to rack structures because it has small size and reduced weight. For both input voltages, the proposed converter has almost the same efficiency processing the same output power. Other relevant features are soft commutation of the controlled switches in the chopper and the boost stage, simple control strategy that can be implemented with well-known integrated circuits, and the use of few batteries in series due to the step-up stage. Qualitative analysis and experimental results obtained from 2kVA laboratory prototype are presented.

This paper presents a novel Wind Energy Conversion System (WECS) capable of processing the energy from a Permanent Magnetic Synchronous Generator (PMSG) coupled to a three-blade wind turbine and injecting it into the utility power grid. This WECS is composed by two stages: a three-phase rectifier and a single-phase inverter. The ac-dc stage consists of three single-phase bridgeless rectifiers processing the power of each phase of the PMSG separately. The dc-ac stage is composed of a full-bridge inverter with controlled output current. Besides, indirect current control for High Power Factor (HPF) operation is employed, allowing the unification of two important techniques currently available, that are one cycle control (OCC) and selfcontrol (SC). Additionally, a third technique, that comprises the optimum characteristics of both OCC and SC, is proposed and applied to the rectifier stage of the proposed WECS. The proposed WECS and control technique are both validated by experimental results from a 5kW prototype.

Resumo-Este artigo trata do estudo de um sistema eólico de pequeno porte utilizado para carregamento de baterias. Uma topologia que visa o aproveitamento da energia gerada em baixas velocidades é proposta. As características da turbina eólica e do gerador utilizado são discutidas, dando uma completa visão da modelagem do sistema. Uma simulação do sistema (MATLAB-SIMULINK) também é feita e os resultados simulados são discutidos e comparados com os experimentais, obtidos a partir de um protótipo de 1kW, de modo a validar a proposta do aproveitamento na energia gerada em baixas velocidades (130 A 270 rpm). Palavras-Chave-Carregamento de baterias, controle de máxima potência, geração eólica.

This paper presents an adapted carrierbased PWM modulation technique to be applied on both Neutral Point-Clamped (NPC) and Flying Capacitor (FC) structures of multilevel inverters. The proposed modulation leads to an improved performance on the output voltage THD. It also reduces the total loss dissipation across the semiconductors devices compared to other conventional carrier-based PWM modulation techniques, such as Phase-Shifted PWM (PSPWM) and Level-Shifted PWM (LSPWM). In order to demonstrate the effectiveness of the proposed technique, it was developed a three-phase, three-level, 6kW prototype for both NPC and FC topologies.