Programa de Pós-graduação em Engenharia Elétrica e da Computação

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Agora exibindo 1 - 20 de 39

Atenuação das componentes oscilantes de conjugado no gerador síncrono de polos salientes
(Universidade Federal de Goiás, 2018-08-30) Aleluia Junior, Leovir Cardoso; Alves, Aylton José; http://lattes.cnpq.br/2762752291082988; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Alves, Aylton José; Pinheiro Neto, Daywes; Domingos, José Luiz; Oliveira, Marco Antônio Assfalk de
The present work is devoted to the development of a methodology for attenuation of the electromagnetic conjugate oscillations using insertion of AC components added to DC components in the field excitation of the synchronous generator of outgoing poles submitted to non-sinusoidal voltage conditions. It is used mathematical modeling able to consider the effects of harmonic components of current and voltage and study is carried out on the oscillations of conjugate using computational simulations. The synchronous generator is connected to the bus and subjected to sinusoidal and non-sinusoidal voltage conditions with the insertion of linear and non-linear loads. It is verified that the conjugate oscillations are influenced by the insertion of nonlinear loads, inducing the periodic behavior, being the main components of the sixth order and their multiple. The results obtained reduce the oscillating electromagnetic torque components by approximately 50%.
Potencialização do rendimento do gerador a relutância chaveado empregando técnica de rastreamento associada a controle de tensão otimizado
(Universidade Federal de Goiás, 2020-12-16) Araújo, Wanderson Rainer Hilário de; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Coimbra, António Paulo Mendes Breda Dias; Ribeiro, Luiz Eduardo Bento; Sousa, Marcos Antônio de; Oliveira, Marco Antônio Assfalk de; Calixto, Wesley Pacheco
This work presents the potentialization of the efficiency of the Switched Reluctance Generator (GRC) submitted to the control of the output voltage. The efficiency is enhanced by using tracking technique acting on the switching angles of the power converter. As it is a DC machine, the control of the output voltage is applied to adapt this value to DC-AC conversion systems and load controllers. The PID controller is used and, because it is a controller with only one output, other quantities are not contemplated by the performance of the controller. In this work, there is an interest in enhancing the performance of the GRC to make this type of machine more attractive for generating electricity in distributed systems and in installations without connection to the main distribution network. Therefore, in parallel to the PID controller, a tracking technique is applied to the GRC performance with a disturb and observe algorithm. Other procedures are presented, such as obtaining an inductance surface to improve the mathematical and computational modeling of the generator, in addition to the development of an indirect conjugate detection system. Simulation and experimental results are presented for validation and discussion of the proposed study.
Processo de otimização aplicado no projeto térmico e luminoso de luminárias de Led de alta potência
(Universidade Federal de Goiás, 2022-11-25) Barbosa, José Luiz Ferraz; Simon, Daniel John; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Magalhães, Alana da Silva; Reis, Márcio Rodrigues da Cunha; Cruz Junior, Gelson da; Marques, Leonardo Garcia
This work develops an optimization methodology for the design of high power LED luminaires – HP-LED. The objective is to design a luminaire with optimized geometry and LED quantity. The solution to the problem must have an illuminance uniformity factor in the illuminated area according to standards established by regulations and adequate thermal management that guarantees luminous flux and lifetime within the nominal standards established by the HP-LED manufacturer. A computational model of the geometry of the HP-LED luminaire is used, in which thermal and optical analyzes are performed through simulators. Simulation and experimental results are presented for validation of the proposed study and from the results of the simulations a multi-objective evaluation function is developed in order to categorize potentially viable solutions. The optimized solution obtained proposes the design of a rectangular luminaire with an arrangement of 2 × 2 HP-LED with a temperature that reaches a maximum value of 73.9oC in steady state and an illuminance uniformity factor of 0.228 for individual lighting. The illuminance uniformity factor found for two adjacent lighting points on pedestrian paths is 0.5413, with minimum illuminance of 36.95lx, maximum illuminance of 93.65lx and average illuminance of 68.27lx. It is concluded that the metric developed in this proposal is capable of evaluating lighting criteria and nominal criteria of thermal limitation, even managing to classify different types of luminaires.
Metodologia de otimização de lentes para lâmpadas de LED
(Universidade Federal de Goiás, 2013-06-14) Barbosa, José Luiz Ferraz; Brito, Leonardo da Cunha; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Brito, Leonardo da Cunha; Yamanaka, Keiji; Alves, Aylton José; Marra, Enes Gonçalves
The purpose of this work is to present a methodology for optimizing the geometry of the Light Emitting Diode (LED) secondary lens, in non-imaging applications, which focuses on the distribution of illuminance on a target plane. The simulation of Ray Tracing is produced by stochastic method and the optimization process based on heuristic search interacts with Ray Tracing to nd the optimized parameters of the LED secondary lens geometry.
Controle inteligente para maximização da geração de potência em termogeradores
(Universidade Federal de Goiás, 2019-03-29) Bezerra, Carlos Daniel de Sousa; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Naka, Marco Hiroshi; Alves, Aylton José; Pinheiro Neto, Daywes; Lemos, Rodrigo Pinto
This work presents a theoretical and experimental analysis of the physical connection and intelligent control of DC-DC converters to the Seebeck thermoelectric generating system. The methodology is based on the application of heuristic optimization methods for the tuning of controllers, observing the transient and permanent responses. It is also developed methodology using artificial neural network associated with the control in voltage mode, necessary for the tracing of the maximum power of the thermogenerator. The computational mathematical model of voltage converter, thermogenerator, controller based on the place of roots, non-pre-phase systems and control techniques is described. The computational simulations and and the practical tests are validated. The results indicate the efficiency of the optimization methods in the tuning of the voltage controller and the best response times for neural networks as a mechanism for tracking the maximum power.
Mineração de opinião em mídias sociais com aprendizado de máquina
(Universidade Federal de Goiás, 2020-10-14) Brandão, Jhonathan de Godoi; Calixto, Wesley Pacheco; https://orcid.org/0000-0002-1928-4432; Calixto, Wesley Pacheco; Ribeiro, Luiz Eduardo Bento; Reis, Márcio Rodrigues da Cunha; Cruz Junior, Gelson da; Marques, Leonardo Garcia
The aim of this work is to develop a tool for that optimizes supervised machine learning models in order to classify polarity of opinions in tweets. Five different datasets are used, which are prepared, preprocessed and then used as input for the training and evaluation stage of machine learning models. The best accuracy results obtained in the training and evaluation of the models are 82.45% for the data without preprocessing × 78.83% with all the proposed preprocessing for the dataset using the Naive Bayes classifier. Finally, hyperparametric optimization of the classifiers and selection of the model that obtains the best accuracy is performed. The optimized model achieves an accuracy greater than 90% for some data sets. The supervised learning techniques depend on labeled data for training, the proposed method produces similar performances for datasets of varying sizes, which allows the development of optimized classification models with reduced amount of labeled data.
Metodologia de previsão utilizando identificação de sistemas aplicada a séries temporais
(Universidade Federal de Goiás, 2018-10-29) Bulhões, Júnio Santos; Calheiros, Débora Fernandes; http://lattes.cnpq.br/6343238272229162; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Calheiros, Débora Fernandes; Oliveira, Sérgio Botelho de; Pinheiro Neto, Daywes; Oliveira, Marco Antonio Assfalk de
This work proposes a methodology that uses spectral analysis and system identification in order to fill gaps in time series. The methodology proposes the implementation of predictions in time series of physical and chemical variables that are related with flood areas that are collected with no frequency. It is used predictive neural network with autoregressive model and classification neural network. Collected values are extracted from the original data set in order to later test and validate the proposed methodology. The results demonstrated the effectiveness of the methodology, which is able to predict the behavior of different variables using the previously recognized patterns in the time series.
Controle e estabilização de aeronaves não tripuladas submetidas a falhas nos motores
(Universidade Federal de Goiás, 2024-06-07) Bulhões, Júnio Santos; Magalhães, Alana da Silva; http://lattes.cnpq.br/4812531916179139; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Magalhães, Alana da Silva; Coimbra, Antonio Paulo; Araújo, Wanderson Rainer Hilário de; Martins, Marcella Scoczynski Ribeiro
The objective of this work was to develop a methodology that utilizes control techniques to stabilize unmanned aerial vehicles subjected to engine failures. The methodology includes the creation of a test bench that allows independent rotational movements of ϕ and θ, eliminating translational movements and reducing its interference with the aircraft’s inertia matrix. Control techniques are implemented to stabilize the aircraft in situations of propulsor failure. The experiments demonstrate an improvement in the aircraft’s stability, with a reduction of more than 80% in the effects produced by the failure in the initial moments and the maintenance of stability in scenarios with up to 30% propulsor performance degradation. The proposed method surpasses other approaches in terms of efficiency and preservation of the aircraft’s autonomy. Both the developed test bench and the simulator are validated, and the auxiliary control that operates post-failure is tested in simulation and on the test bench, demonstrating its ability to stabilize the aircraft during failures in one of its propulsors, providing a viable and efficient solution for real-world situations.
Análise e otimização da rede de distribuição de energia utilizando conceitos de redes inteligentes
(Universidade Federal de Goiás, 2021-10-21) Caetano Neto, João; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Reis, Márcio Rodrigues da Cunha; Lemos, Rodrigo Pinto; Marques, Leonardo Garcia; Magalhães, Alana da Silva
The main objective of this work is to develop a methodology for analyzing the quality of the voltage level in the distribution power grid to identify and re-duce the violations of voltage limits through the proposition of optimal points for the allocation of photovoltaic distributed generation. The methodology uses the geographic location of the power grid and its consumers to perform the grouping and classification in spatial grids of 100×100 m using the average annual consumption profile. The generated profiles, including the grid infor-mation, are sent to the photovoltaic distributed generation allocation algo-rithm, which, using an optimization process, identifies the geographic location, the required installed capacity, and the minimum number of photovoltaic gen-eration units that must be inserted to minimize the violations of voltage limits, respecting the necessary restrictions. The entire proposal is applied in a real feeder with thousands of bars, whose model is validated with measurements carried out in the field. Different violations of voltage limits scenarios are used to validate the methodology, obtaining grids with better voltage quality after the optimized allocation of photovoltaic distributed generation. The proposal presents itself as a new tool in the work of adapting the voltage of the distri-bution power grid using photovoltaic distributed generation.
Processo de otimização aplicada na adequação de tensão utilizando geração distribuída fotovoltaica
(Universidade Federal de Goiás, 2018-08-29) Cararo, José Alberto Gobbes; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Reis, Márcio Rodrigues da Cunha; http://lattes.cnpq.br/1167385371830496; Pinheiro Neto, Daywes; Gomes, Raphael de Aquino; Ribeiro, Luiz Eduardo Bento; Nerys, José Wilson Lima
This work presents methodology for voltage adequacy into electric power distribution network with the insertion of photovoltaic distributed generation. Deterministic, heuristic and hybrid optimization methods are used to find the variables: i) geographical siting, ii) supply power and iii) amount of photovoltaic distributed generation. The main characteristic of the methodology is the obtaining of the amount of photovoltaic distributed generation units necessary for the adequacy of electric network voltage, respecting the supply power of each generation unit. The results indicate improvement in voltage levels after insertion of photovoltaic distributed generation units with optimized parameters for different voltage transgression scenarios. The proposed methodology is efficient for voltage adequacy through the insertion of photovoltaic distributed generation.
Sintonia de controlador preditivo não linear: análise comparativa com técnicas tradicionais
(Universidade Federal de Goiás, 2017-11-20) Carvalho, Douglas Freire de; Ganzaroli, Cleber Asmar; http://lattes.cnpq.br/7006345437314171; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Ribeiro, Luiz Eduardo Bento; Oliveira, Eider Lúcio de; Nerys, José Wilson Lima
This work presents study of nonlinear predictive controller, tuned by optimization process, applied to independent excitation DC motor speed control, controlled by fully controlled three phase rectifier. The methodology starts from the construction of the workbench that represents the real system followed by the development and validation of the computational model. The optimization process promotes the obtaining of optimized parameters for the nonlinear model based predictive controller to be implemented in the real process. Comparisons are made between the control technique proposed with classical control techniques, in computational and real environment. The results indicate the prominence of the proposed technique to be used in control of non-linear systems where seeks smaller errors even with disturbance insertions.
Aplicação da inteligência artificial, ontologia e mineração de dados para classificação de sentenças judiciais
(Universidade Federal de Goiás, 2021-12-20) Castro Junior, Antonio Pires de; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Peretta, Igor Santos; Araújo, Wanderson Rainer Hilário de; Soares, Fabrizzio Alphonsus Alves de Melo Nunes; Gomes, Viviane Margarida; Calixto, Wesley Pacheco
The objective of this work is to apply together ontology with bag-of-words models, similarity learning, and document classification in texts with uttered decisions. The objective is to improve the results of data mining in a database of court decisions. An automatic method of searching sentences in judicial processes related to the one under judgment is developed using the frequency term-inverse of frequency in documents model together with the Jaccard similarity coefficient, establishing weights on the co-occurrence of terms in legal texts of the same category. A dataset with document vectorization is used for supervised training of machine learning algorithms, aiming to classify new justice processes. The proposed methodology provides flexibility to the Judiciary, simulating the role of legal advisors in preparing court decisions with less time and efficiency in the search for jurisprudential standards. The results obtained show that, through accuracy metrics, the proposed model is effective and efficient, and can be applied in the process of identification of court decisions. Thus, the application of artificial intelligence, ontology, and data mining is indicated for information retrieval in court decisions.
Implementação e análise das técnicas de controle por modos deslizantes e preditivo não linear
(Universidade Federal de Goiás, 2018-08-31) Couto, Luiz Alberto do; Ganzaroli, Cleber Asmar; http://lattes.cnpq.br/7006345437314171; Calixto, Wesley Pacheco; http://lattes.cnpq.br/907347819202786
This work presents an implementation and analysis of traction control and linear trepidation techniques, driven by a six - pulse fully controlled three - phase rectifier. The methodology addresses the construction of real reality, modeling by method of system identification, design and tuning of optimization processes. The comparisons between the techniques are their characteristics and their performances when performing statistics, verifying the robustness of the series in non-linear systems. Both techniques perform satisfactory in the execution of the control, correlating with the.
Análise comparativa de técnicas de controle Fuzzy e matriz dinâmica aplicadas à máquina de corrente contínua
(Universidade Federal de Goiás, 2017-11-27) Dias, Rafael Nunes Hidalgo Monteiro; Ganzaroli, Cleber Asmar; http://lattes.cnpq.br/7006345437314171; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Pinheiro Neto, Daywes; Siqueira, Ildeu Lúcio; Oliveira, Marco Antônio Assfalk de
This work presents a comparison between Fuzzy and dynamic matrix controllers. These controllers are applied to the direct current (DC) motor speed control, triggered by fully controlled three-phase rectifier. The construction of the real system and the development and validation of the computational model are described. The controllers’ parameters are obtained through an optimization process. Both control techniques are compared and results indicate better performance of the optimized controllers, which suggest their promise in nonlinear systems’ control, in which seeks out control without error, that fulfills well its duty and its able to resist the fatigues.
Dispositivo para medição de impedância em sistemas de aterramento elétricos em alta frequência
(Universidade Federal de Goiás, 2016-11-04) Ferraz, Rafael da Silva; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Paula, Samuel Cesar Mota; Alves, Aylton José; Nerys, José Wilson
This work presents the project and the implementation of a device that is capable of measuring the electrical effects, especially the impedance, in grounding meshes when subjected to atmospherical discharges. An analysis on the influence of the atmospheric discharges in electrical protection systems is performed and also a comparison between current and voltage impulsive circuits. The device is built of electronic circuits controlled by a microcontroller, with the possibility of parameter adjusting for shaping the generated impulse wave. The device was conceived such that it can be used for tests of soil impedance measurement and for verification of the behavior of electrical grounding systems under high frequencies. The results are presented for tests in different types of systems and there was satisfactory performance for the developed equipment when compared with a commercial device
Acústica aplicada no desenvolvimento de equipamentos para agricultura de precisão
(Universidade Federal de Goiás, 2022-07-08) Furriel, Geovanne Pereira; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Silva, José Geraldo da; Araújo, Wanderson Rainer Hilário de; Jakelaitis, Adriano; Cruz Junior, Gelson da
This work presents methodology for development of precision agriculture equipment based on acoustic and vibration techniques. The proposed methodology uses the scale reduction method to simulate the induced vibration and the direction of sound pressure fields. After analyzing the scale-down model, the prototype is built in real dimensions to validate the proposed system. Two acoustic induction systems are designed and evaluated, one for applying phytosanitary products and the other for selective fruit harvesting. When applying the phytosanitary product, there is a reduction in drift and an increase in leaf coverage by approximately 45%. In the selective harvest, the proposed method is analyzed, and approximately 40% of the fruits were harvested at the appropriate maturation stage. The acoustic techniques presented applied to agriculture are promising for developing equipment for handling and harvesting in precision coffee farming. The results indicate that using acoustic techniques promotes the reduction of the inherent wear of the harvest in the plants.
Desenvolvimento e validação de aparelho automático para medição da compactação do solo
(Universidade Federal de Goiás, 2016-08-16) Furriel, Geovanne Pereira; Alves, Aylton José; http://lattes.cnpq.br/2762752291082988; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Alves, Aylton José; Silva, José Geraldo da; Oliveira, Marco Antônio Assfalk de; Narciso, Marcelo Gonçalves
The purpose of this work is to present the development of automatic instrument for measuring soil compaction through penetration resistance. Commonly, this measurement is performed by load cells. In the proposed methodology and apparatus, the penetration resistance is directly measured by the current applied to the motor that performs penetration of the rod into the soil, thus replacing the load cell. The collected data are stored in Datalogger and further processed in order to enable analysis and the generation of maps of the surface with soil compaction values up to a certain depth. The presented results indicate greater precision and control of the fundamental parameters of data acquisition.
Estudo, implementação e otimização de técnicas de controle avançado
(Universidade Federal de Goiás, 2022-10-06) Ganzaroli, Cleber Asmar; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Magalhães, Alana da Silva; Calixto, Wesley Pacheco; Gomide, Renato de Sousa; Lemos, Rodrigo Pinto; Araújo, Wanderson Rainer Hilário de
This work proposes the tuning, implementation, analysis and comparison of different control strategies applied to the same system. The controllers studied are: Proportional, Integral and Derivative, Nonlinear Predictive, Fuzzy Control and Sliding Mode Control. These techniques are applied to the speed control of an independently excited DC motor driven by a fully controlled three-phase rectifier. The methodology proposes the bench design, the modeling of the real system by the system identification method, the sensitivity analysis and the adjustments of the controllers parameters using an optimization process. Comparisons are made between the techniques, highlighting their characteristics and performance considering similar conditions of execution. The robustness of each control when acting on a non-linear system is investigated. All control techniques are applied in three different tests: i) step-type reference signal, without load application, ii) reference signal with amplitude variation, without load application and iii) step-type reference signal, with load application. The techniques present satisfactory performance in the execution of the proposed control, depending, therefore, on the analysis of the system to be implemented to determine the appropriate method.
Processo de otimização aplicado em método descritivo da análise de dados
(Universidade Federal de Goiás, 2018-02-21) Gomes, Flávio Adalberto; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Oliveira, Eider Lúcio de; Fonseca, Regina Célia Bueno da; Oliveira, Marco Antônio Assfalk de
This work presents methodology for construction and optimization of mathematical structures that represent experimental data. A hybrid optimization process between an heuristic method and a direct search deterministic method is used. Input and output values of real systems are used and some mathematical expressions are formulated to be used as test and validation. The results are compared with traditional methods, analyzing the oscillations at the edges. The proposed method presents a feasible solution for experimental data analysis and extrapolation, with reduced mathematical expressions.
Geometria de dutos de escape otimizada para aplicação na cogeração da produção de energia elétrica
(Universidade Federal de Goiás, 2017-12-05) Gomes, Pedro Henrique Garcia; Alves, Ayton José; http://lattes.cnpq.br/2762752291082988; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Alves, Ayltom José; Domingues, Elder Geraldo; Oliveira, Eider Lúcio de; Oliveira, Maco Antônio Assfalk de
The objective of this work is to seek greater efficiency in energy conversion using the Seebeck modules, from the duct geometry optimization exhaust hot gases. Different materials and geometries are tested. The duct thickness was varied along the longitudinal fluid flow and optimized parameters are obtained heuristically . After the development of optimized duct model, a prototype is built for testing in the actual system. From the resistive air layer, the surface temperature gradient equalization is obtained, improving the efficiency of the system.

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