Bruno Ricardo de Almeida

Didactic system for digital control of power electronics applications

This paper presents the development of an educational system for controlling power electronics systems with digital signal controllers (DSCs). This system is composed of five prototypes for the development of digital controllers. The applications were in the area of power electronics, including power converters and electrical machine drives. The kits were developed to allow verification of the models and validation of the digital controller design of the implemented circuits. The interdisciplinary nature of the educational system is highlighted in this project, where the student comes into contact with various concepts related to different subjects, such as power electronics, analog electronics, control systems, digital control, and digital signal processors.

Power converter for vertical wind energy conversion system

The wind energy conversion system (WECS) presented in this paper is based on permanent magnet generators coupled to a vertical-axis turbine. The proposed topology is formed by a three-phase PWM rectifier and a step-down dc-dc converter, based in a buck-interleaved using the three-state switching cell (TSSC). That topology realizes the power factor correction (PFC) what mitigates the audible noise issue, the turbines maximum power point tracking (MPPT), what maximizes the energy extract from the wind as well as is able to manage the battery charge. The experimental results from a 1.5 kW prototype are presented and discussed.

A bidirectional single-stage three-phase rectifier with high-frequency isolation and power factor correction

This paper proposes a single-stage three-phase rectifier with high-frequency isolation, power factor correction, and bidirectional power flow. The presented topology is adequate for dc grids (or smart-grids), telecommunications (telecom) power supplies, and more recent applications such as electric vehicles. The converter is based on the three-phase version of the dual active bridge (DAB) associated with the three-state-switching cell (3SSC), whose power flow between the primary and secondary sides is controlled by the phase-shift angle. A theoretical analysis is presented and validated through simulation and experimental.

Distributed generation system using renewable energy sources and a new converter topology

This paper presents the development of a renewable energy-based distributed generation (DG) system able to operate in standalone or grid-connected mode. When the utility ac grid if disconnected, the DG system can still supply part of the local loads. The proposed system consists of a wind turbine generator, solar photovoltaic (PV) modules, a battery bank, and two power converters arranged in an experimental setup. The first converter is a bridgeless boost rectifier, which is connected directly to the wind turbine and responsible for the speed control and tracking the maximum power point (MPP). The second converter is a bidirectional ac-dc topology bidirectional multi-port, connects these energy sources to the grid, the main functions: Setting the converter bus wind generator; performing the charge and discharge of the battery bank; MPPT in photovoltaic panels; and energy injection generated in the local grid. After studying the art of distributed generation and the context of the proposed system are described the two converters developed in the laboratory, where it is made a brief analysis of each of them. Simulation results preliminary experimental results are presented validating the developed analysis and operation of developed topologies.

Modulation technique for a single-stage three-phase bidirectional AC/DC converter with PFC and high-frequency isolation

This paper proposes a single-stage three-phase ac-dc converter with high-frequency isolation, power factor correction, and bidirectional power flow. The presented topology is adequate for dc grids (or smart-grids), telecommunications (telecom) power supplies, and more recent applications such as electric vehicles. The converter is based on the three-phase version of the dual active bridge (DAB) associated with the three-state-switching cell (3SSC), whose power flow between the primary and secondary sides is controlled by the phase-shift angle. A theoretical analysis is presented and validated through simulation.

Control system for vertical-axis WECS

This paper introduce the design of a static converter for a vertical-axis wind energy conversion system (WECS), based on permanent magnet generators. This turbine presents low speed and high torque, characteristics that will be explored in the converter project. The proposed topology, formed by a high frequency semi-controlled rectifier and a step-down dc-dc converter, realizes the turbines maximum power point tracking (MPPT) and protects battery from surge and over current. The principal advantages of using the semi-controlled rectifier are: simplicity, since all active switches are connected to a common point, robustness, as short-circuit through a leg is impossible to happen and high efficiency due to reduced number of elements. One disadvantage is the high total harmonic distortion (THD) produced; nevertheless, its value is in an acceptable range. A system overview, the vertical-axis wind turbine characteristics, the power generator, the power converter and control system are presented. Simulation results are compared with experimental results from a 1.5 kW laboratory prototype.

Medição digital aplicada a estabilizadores e condicionadores CA

This paper deals with the digital measurement of the true RMS value for use in controlling of AC voltage regulators and in controlling of line conditioners. The algorithms used to calculate the RMS value are presented, as well as the factors that influence the determination of this value. Some aspects are analyzed, as the definition of the true RMS value, the determination of the sampling rate of the signals and the effect of voltage harmonics. Experimental results show the functionality of the hardware implemented where the programs developed are tested to verify the accuracy and calculation time of measurements.