DEELT - Artigos publicados em periódicos

URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/5267

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2020 - 20215

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Autor: search.filters.author.Barbosa, Pedro GomesData inicial: 2020

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Agora exibindo 1 - 5 de 5
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    Comparative performance of three phasor-extraction algorithms for co-simulation of electrical power systems.
    (2021) Theodoro, Thainan Santos; Barbosa, Pedro Gomes; Tomim, Marcelo Aroca; Lima, Antonio Carlos Siqueira de
    This work presents a comparison of the three phasor extraction algorithms proposed in the literature for the co-simulation of transient stability and electromagnetic transients programs. Initially, a brief mathematical review of two algorithms widely used in the literature is made: the discrete Fourier transform and the adjustment of the least-squares curve. In addition, a technique proposed by the authors based on the use of the generalized second-order integrator is presented. Then, these three techniques will be implemented and evaluated numerically through a comparative performance study extracting the fundamental phasor component of a test signal.
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    Dispatchable distributed generation using a back-to-back converter for grid-forming improvements based on feed-forward action with load current prediction.
    (2020) Fogli, Gabriel Azevedo; Souza, Igor Dias Neto de; Fernandes, Marcelo Carvalho; Almeida, Pedro Machado de; Barbosa, Pedro Gomes
    This work deals with the control law design and experimental verification of a grid-forming dispatchable distributed generation based on a back-to-back converter. The proposed system brings several improvements to the prime mover as well as to the microgrid voltage quality. The control strategy is based on an inner current and an outer voltage loop for both sides of the converter. The external loop of the back-to-back input side, which is connected to the generator, is responsible for regulating the DC voltage. On the other hand, in the output side, the voltage loop ensures a high-quality AC waveform to feed the loads. A comprehensive discussion regarding the current controller with harmonic mitigation is performed to justify the controller's choice. It is shown that a suitable current controller significantly improves the disturbance rejection. A feed-forward compensation based on the load current prediction without any additional sensor is proposed to improve the output voltage quality. Experimental results are used to validate the proposed control law and to show the improvements and benefits of the system.
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    Systematic design of a DLQR applied to grid-forming converters.
    (2020) Almeida, Pedro Machado de; Ribeiro, Adeilson da Silva Borges; Souza, Igor Dias Neto de; Fernandes, Marcelo Carvalho; Fogli, Gabriel Azevedo; Cuk, Vladimir; Barbosa, Pedro Gomes; Ribeiro, Paulo Fernando
    This article proposes a systematic state-space procedure to design an optimal discrete-time linear quadratic regulator applied to grid-forming converters. A comprehensive mathematical modeling of a voltage-sourced converter with an LC output filter is performed and a systematic way of including digital resonant compensators is addressed. The choice of weights is based on the minimization of selected transfer functions infinity norm, as well as on the stability margin and bandwidth. The effects of weighting on closed-loop transfer functions shape are analyzed and important points are discussed in order to establish a methodical way of choosing the weighting matrices. Experimental results are presented to validate the design and to demonstrate the system effectiveness with high loading and highly nonlinear balanced and unbalanced loads.
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    Low-frequency underwater wireless power transfer : maximum efficiency tracking strategy.
    (2020) Lopes, Israel Filipe; Valle, Rodolfo Lacerda; Fogli, Gabriel Azevedo; Ferreira, André Augusto; Barbosa, Pedro Gomes
    This paper proposes a strategy to improve the efficiency of a low-frequency Wireless Power Transfer (WPT) system used to charge the battery of an Autonomous Underwater Vehicle (AUV) through an Inductive Power Transfer (IPT). The IPT system uses a Split-Core Transformer (SCT) to transfer power from the docking base to the AUV, without electric contact. Under gap variation, the efficiency is changed because the variation of SCT parameters. Therefore, the input frequency is changed in order to improve the efficiency of the system trough the Maximum Efficiency Point Tracking algorithm (MEPT) without communication between primary and secondary sides. Experimental results are presented to validate the theoretical analysis and to demonstrate the behaviour of the transformer under different values of gap and excitation frequency.
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    Simple and effective digital control of a variable-speed low inductance BLDC motor drive.
    (2020) Valle, Rodolfo Lacerda; Almeida, Pedro Machado de; Fogli, Gabriel Azevedo; Ferreira, André Augusto; Barbosa, Pedro Gomes
    This paper presents a simple digital control applied to a low inductance 5 kW/48 V three-phase brushless DC motor. Controlling the VSI as a full-bridge converter allowed the use of unipolar switching strategy, increasing the output equivalent frequency up to 100 kHz. The aforementioned strategy has made it possible to control the three-phase currents using a single deadbeat controller without a back-EMF feed-forward compensation. Stability analysis is performed to show that the proposed current control presents good transient response under reasonable parametric variations, as well as zero steady-state error. Precise regulation with no overshoot was obtained using an IP controller to regulate the motor speed. Experimental results are presented to validate the theoretical analysis and to compare with a conventional PI compensator and a predictive controller.