Doutorado em Engenharia Elétrica

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Agora exibindo 1 - 5 de 151

Cooperative load transportation by quadrotors
(Universidade Federal do Espírito Santo, 2025-09-30) Bacheti, Vinícius Pacheco; Brandão, Alexandre Santos; https://orcid.org/0000-0001-5990-2218; https://lattes.cnpq.br/7313802049311709; Castilho, Pedro; https://orcid.org/0000-0001-8324-8762; ; Sarcinelli Filho, Mário; https://orcid.org/0000-0002-7696-8996; https://lattes.cnpq.br/3459331011913021; https://orcid.org/0000-0003-0311-732X; https://lattes.cnpq.br/4263495472789334; Lozano, Rogelio; https://orcid.org/0000-0002-5730-6313; http://lattes.cnpq.br/; Rosales, Cláudio Dário; https://orcid.org/0000-0001-6033-0413; http://lattes.cnpq.br/; Colombo, Leonardo; https://orcid.org/0000-0001-9513-3268; http://lattes.cnpq.br/; Salles, José Leandro Félix; https://orcid.org/0000-0002-3417-6544; https://lattes.cnpq.br/1368496315730875
This thesis presents a study on the cooperative transportation of cable-suspended payloads using quadrotors. The central contribution is the development of a control framework that closes the loop on the payload by exploiting the resultant cable tensions to achieve trajectory tracking. The work begins with a study on a single off-the-shelf drone transporting a load, marking the author’s first steps in modeling and controlling aerial systems with cable-suspended payloads. After, the first version of the tension-based control framework is proposed for a team of n quadrotors carrying a single payload. This framework supports dynamic reconfiguration, allowing both geometric adjustments of the formation and the addition or removal of agents. Simulations and experiments demonstrate the effectiveness of the approach, including during reconfiguration events. Subsequently, a novel attitude controller is introduced, replacing the one used in earlier versions of the framework. Two further iterations of the framework are then proposed. The f irst incorporates an adaptive sliding mode control law, improving resilience against unmodeled dynamics and external disturbances such as wind gusts. Extensive experimental validation shows that this adaptive robust controller not only outperforms the previous framework but also surpasses a standard PID baseline. The second iteration augments the system with a potential field–based mechanism, designed to prevent intra-formation collisions. This addition improves safety and demonstrates scalability through experiments with n = 5 agents. Results reveal that the repulsion force not only prevents collisions but also enhances the overall performance of the transportation task.
Sensoriamento utilizando interferômetros do Sagnac em fibra na região do infravermelho e terahertz
(Universidade Federal do Espírito Santo, 2025-12-12) Pizzaia, João Paulo Lebarck; Leal Júnior, Arnaldo Gomes; https://orcid.org/0000-0002-9075-0619; http://lattes.cnpq.br/7246557168481527; Castellani, Carlos Eduardo Schmidt; https://orcid.org/0000-0003-4154-5683; http://lattes.cnpq.br/1975160943820607; https://orcid.org/0000-0001-6282-2120; http://lattes.cnpq.br/0557675866537606; Pontes, Maria José; https://orcid.org/0000-0002-9009-2425; http://lattes.cnpq.br/4148956242627659; Díaz, Camilo Arturo Rodríguez; https://orcid.org/0000-0001-9657-5076; http://lattes.cnpq.br/2410092083336272; Werneck, Marcelo Martins; https://orcid.org/0000-0002-8804-0503; http://lattes.cnpq.br/9106754041376544; Marques, Carlos Alberto Ferreira; https://orcid.org/0000-0002-2799-643X
Optical sensors stand out for their high sensitivity, reduced dimensions and weight, immunity to electromagnetic interference, and safety in potentially explosive environments. Among the various existing configurations, the Sagnac interferometer is widely recognized for its use in high-precision optical gyroscopes, but it has been increasingly employed in sensing applications of different physical quantities due to its high sensitivity. However, as occurs in other fiber-optic systems, its practical implementation may be limited by the cost associated with optical components and analysis instruments, such as the optical spectrum analyzer (OSA). In this Thesis, the mathematical modeling and the numerical and experimental development of different Sagnac interferometer configurations are presented, ranging from simple setups to arrangements with multiple optical elements in the loop. The focus of the work is on reducing the implementation and maintenance costs of Sagnac optical interferometers without compromising sensitivity, as well as on proposing new applications operating in the terahertz spectral region. In one of the proposed configurations, a force sensor based on a simple Sagnac interferometer setup was developed, using standard single-mode fiber as the sensing element in place of the polarization maintaining fiber usually employed. This modification enabled reliable measurements with a sensitivity of–0.116 nm/N, in addition to significantly reducing maintenance costs, since fiber replacement is low-cost in the event of rupture due to overload. For vibration monitoring, a simplified configuration capable of operating over a wide frequency range (50–22,000 Hz) was implemented, achieving a correlation coefficient (R2 = 0.9696) for frequency detection. In the terahertz region, a refractive index sensor based on photonic crystal fiber was modeled and simulated, yielding correlation coefficients of 0.999 and 0.987 for third- and second-order polynomial fits, respectively. The results demonstrate that the proposed configurations maintain high levels of sensitivity while employing less complex sensing systems. Thus, this work contributes to advances in the research and development of optical sensors based on Sagnac interferometers, making them simpler, more accessible, and more viable alternatives for scientific applications.
Technologies for modern optical networks: prototyping and testing
(Universidade Federal do Espírito Santo, 2025-02-19) Santos, Caio Marciano; Pontes, Maria Jose ; https://orcid.org/0000-0002-9009-2425; http://lattes.cnpq.br/4148956242627659; Segatto, Marcelo Eduardo Vieira; https://orcid.org/0000-0003-4083-992X; http://lattes.cnpq.br/2379169013108798; https://orcid.org/0000-0001-8237-357X; http://lattes.cnpq.br/5060786623885022; Silva, Jair Adriano Lima; https://orcid.org/; http://lattes.cnpq.br/3099010533644898; Rocha, Helder Roberto De Oliveira; https://orcid.org/0000-0001-6215-664X; http://lattes.cnpq.br/8801325729735529; Araújo, Murilo Romero; https://orcid.org/0000-0002-2312-7253; http://lattes.cnpq.br/4009508060687531; Nunes, Reginaldo Barbosa ; https://orcid.org/0000-0001-8877-1480; http://lattes.cnpq.br/0301147577506989
Optical recirculation loops are essential tools in the study of long-haul optical fiber communication systems. The technique allows light to travel for multiple rounds through f iber spans, simulating extended transmission distances without the need for physically long fiber setups. As a laboratory tool, it is particularly useful for investigating the effects of amplifier noise and optical nonlinearity in long-haul links. In other contexts, it is widely used for validating and designing submarine networks, these of which are crucial to our modern networks, bringing connectivity across the globe. The advent of 5G technology, combined with Optical Wireless Systems (OWS), promises to revolutionize communication networks. 5G offers unprecedented transmission rates and connectivity, while OWS provides a complementary solution for high-capacity, short-range communication. Together, they enable a wide range of applications, from enhanced mobile broadband to ultra-reliable low-latency communications, supporting the growing demand for data and connectivity in smart cities and industrial automation. 5G New Radio (NR) represents the global standard for the air interface of 5G networks, developed by the 3rd Generation Partnership Project (3GPP). Using advanced technolo gies such as orthogonal frequency division multiplexing (OFDM), massive MIMO, and beamforming to deliver lower latency, higher capacity, and improved spectral efficiency. 5G NR supports a wide range of frequency bands and deployment modes, making it a versatile and scalable solution for future wireless communication needs. When merging recirculation loops with 5G technology and standardization, a robust OWS is created, capable of delivering signals in the most vast environments. Thus, this work presents the design, execution, and validation of a recirculation loop prototype, as well as the validation of a 5G antenna prototype developed by a third party. With the standalone loop, distances of up to 100, 600, 900 and 1400 km are achieved at 3.65, 2.94, 2.21, and 1.47 Gb/s, respectively. In the OWS containing the loop and the antenna prototype, distances of up to 100 km and 500 km for 1.94 and 1.46 Gb/s, respectively. Finally, for a 5G NR OWS operating within the FR1 n77 band, with a total of 450 MHz allocated for four individual 100 MHz channels, transmission distances of 400 km for channel 1, and 500 km for channels 2 to 3 were obtained with a raw rate of 229.5 Mb/s per channel.
Primary-side power capability estimation for optimal current distribution in LCC-LCC compensated multi-transmitter lnductive power transfer systems
(Universidade Federal do Espírito Santo, 2025-08-20) Lacerda, Macklyster Lãnucy Scherre Stofel de; Santos, Walbermark Marques dos ; https://orcid.org/0000-0002-9871-6028; http://lattes.cnpq.br/5558697161842579; https://orcid.org/0000-0002-6673-8716; http://lattes.cnpq.br/0110962438935308; Encarnação, Lucas Frizera; https://orcid.org/0000-0002-6162-7697; http://lattes.cnpq.br/5578918284508758; Antunes, Helio Marcos Andre; https://orcid.org/0000-0001-8247-6448; http://lattes.cnpq.br/7601860538588447; Rech, Cassiano; https://orcid.org/0000-0001-8225-9240; http://lattes.cnpq.br/9375639768929991; Martins, Denizar Cruz; 0000-0002-0806-1831; http://lattes.cnpq.br/6156546664055944
Inductive Power Transfer (IPT) systems face inherent limitations under misalignment be tween transmitter and receiver coils, leading to reduced magnetic coupling and compromised power capacity and efficiency. Configurations with multiple primary circuits are employed to mitigate these effects. In addition to increased robustness against positional variation, such systems offer improved magnetic field distribution, reduced peak currents, and lower voltage and current stresses on the primary compensation components. Nevertheless, the introduction of multiple primaries creates practical challenges in accurately identifying the power transfer capability of each primary circuit, as this capability is directly influenced by the mutual inductances, which vary dynamically with the spatial position of the secondary coil. To address this challenge, this thesis presents a practical procedure to identify the power transfer capability of each primary circuit in IPT systems with LCC compensa tion topology, based on direct voltage measurements across the primary compensation capacitors. The proposed routine is executed before initiating power transfer, allowing the determination of the power transferable by each primary circuit at specific current levels without requiring knowledge of the secondary coil’s position or complex offline inductance simulations. Based on these results, an optimization problem is formulated to compute the operating currents that minimize conduction losses in the primary inductors, thereby establishing the power distribution among the primary circuits. The proposed method is supported by a mathematical framework initially developed for single-phase LCC IPT systems, where the system is modeled through conductance equations that incorporate the resistive elements of the compensation network. This formulation is then extended to the three-primary, single-secondary configuration. The complete approach—comprising modeling, identification, and optimization—was validated through simulations performed in PSIM for a 1.5 kW IPT system and experimental tests conducted on a 200 W prototype. The system achieved an overall efficiency of approximately 86% in simulations and 64% in experiments. Since the method imposes no mathematical restrictions on power level, it can be applied to IPT systems of any rated power
Desenvolvimento e validação experimental do controle preditivo em conversores DAB e ANPC-DAB aplicados a SST
(Universidade Federal do Espírito Santo, 2025-05-20) Nardoto, Adriano Fazolo; Encarnação, Lucas Frizera; https://orcid.org/0000-0002-6162-7697; http://lattes.cnpq.br/5578918284508758; Bueno Peña, Emilio José; https://orcid.org/0000-0002-0806-1831; Santos, Walbermark Marques dos; https://orcid.org/0000-0002-9871-6028; http://lattes.cnpq.br/5558697161842579; https://orcid.org/0000-0002-5003-698X; http://lattes.cnpq.br/8641259747622403; Simonetti, Domingos Sávio Lyrio; https://orcid.org/0000-0001-5920-2932; http://lattes.cnpq.br/1107005171102255; Coelho, Roberto Francisco; https://orcid.org/0000-0002-4672-0885; http://lattes.cnpq.br/9967005468124403; Martins, Denizar Cruz; https://orcid.org/0000-0002-0806-1831; http://lattes.cnpq.br/6156546664055944; Rech, Cassiano; https://orcid.org/0000-0001-8225-9240; http://lattes.cnpq.br/9375639768929991
This thesis addresses the development of model predictive control (MPC) strategies for ap plication in DAB (Dual Active Bridge) converters, focusing on high-complexity applications that require real-time processing, particularly in multilevel topologies and systems with a large number of switching states. Two approaches were investigated. The first focused on the modular application of the DAB converter, evaluating power distribution among multiple converters connected in parallel on a low-voltage DC bus (LVDC). This topology was experimentally tested on a test bench developed at the Power Electronics and Electric Drives Laboratory (LEPAC) of the Federal University of Espírito Santo. The second approach aimed to increase the efficiency of the DAB converter through predictive control and advanced modulation techniques, such as triangular and trapezoidal modulations, optimizing the converter’s operation under light load conditions. This technique was experimentally tested on the DAB using the ANPC (Active Neu tral Point Clamped) multilevel topology. The test bench was developed at the Energy, Electrical Systems Engineering, and Smart Grids Group (GEISER) of the University of Alcalá de Henares

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