ISEL - Eng. Mecan. - Comunicações
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- Thermo-electrical performance of hybrid busbars: an experimental and numerical investigationPublication . Sampaio, Rui F. V.; Pragana, João P. M.; Bragança, Ivo M. F.; Silva, Carlos M. A.; Martins, Paulo A. F.This paper is focused on hybrid busbars made from aluminum and copper with the purpose of analyzing the influence of temperature on the electric performance of the joints. The methodology involves the fabrication of fastened, friction stir spot welded, sheet-bulk compressed, and injection lap riveted unit cells that are representative of the different types of hybrid busbars joints, the development of a special purpose laboratory apparatus for thermo-electrical measurements, and numerical simulation with a finite element computer program developed by the authors. Results are a step forward in understanding the variation of the electrical resistance of hybrid busbars with temperature and allow concluding that an increase above 30% is expected when the temperature in service reaches the limiting value defined by the IEEE standard for metal-clad switchgear.
- On the utilization of radial extrusion to characterize fracture forming limits. Part II: testing and modellingPublication . Sampaio, Rui F. V.; Pragana; João P. M.; Bragança, Ivo M. F.; Silva, Carlos M. A.; Nielsen, Chris V.; Martins, Paulo A.F.
- On the utilization of radial extrusion to characterize fracture forming limits. Part I – methodology and toolingPublication . Sampaio, Rui F. V.; Pragana, João P. M.; Bragança; Ivo M. F.; Silva, Carlos M. A.; Nielsen, Chris V.; Martins, Paulo A.F.
- An injection lap riveting tool systemPublication . Pragana, João P. M.; Sampaio, Rui F. V.; Bragança, Ivo M. F.; Silva, Carlos M. A.; Martins, Paulo A. F.
- Hybrid additive manufacturing of silver collector coins: an experimental and numerical case studyPublication . Sampaio, Rui F. V. Pragana, João P. M.; Alexandrino, Paulo; Aráujo, Andreia; Bragança, Ivo M. F.; Silva, Carlos M. A.; Martins, Paulo A. F.
- On the characterization of fracture forming limits for highly ductile metals through radial extrusionPublication . Rui F. V. Sampaio; Pragana, João P. M.; Bragança, Ivo M. F.; Silva, Carlos M. A.; Martins, Paulo A. F.
- Diagnosing Power Transistor Faults in Multilevel T-Type Based Nine Switch Inverter Using Center of Mass IndexesPublication . Monteiro, Joaquim; Amaral, Tito; Silva, J. Fernando; Pinto, Sonia; Fernao Pires, VitorNine-switch voltage source inverters (NSVSI) are DC-AC converters that utilize a reduced number of switches, making them advantageous for dual or six-phase motors. To enhance the quality of the output voltage and provide fault tolerant capability, NSVSI topologies, like the T-Type-based NSVSI, have been modified to operate as multilevel converters. However, to ensure fault-tolerant capability, a fault diagnosis algorithm for power transistors must be developed. Therefore, this paper proposes a novel fault detection and diagnosis algorithm to identify faulty transistors in a multilevel T-Type-based NSVSI. This method is based on the development of specific indices derived from the center of mass of the output currents. The proposed technique offers a fast and reliable solution, demonstrating robustness under various load conditions. The effectiveness of this method will be validated through a series of simulation tests.
- Towards a hardware-in-the-loop quantum optical ground station simulator and testbedPublication . Niehus, Manfred; Simão, José; Silva, João Castanheira da; Serrador, António; Carvalho, João M.; Gonçalves Cavaco Mendes, Mário JoséA single pass Bennett-Brassard 1984 protocol quantum key distribution downlink from a small quantum satellite in low earth orbit to an optical ground station is studied with the objective to develop the framework for a hardware-in-the-loop quantum optical ground station simulator and testbed.
- Hardware-in-the-loop testing framework for active accumulator wave energy convertersPublication . Guedes Soares, Carlos; Gonçalves Cavaco Mendes, Mário José; Gaspar, José; Zeng, ChenThe hardware-in-the-loop technique is a hybrid co-simulation approach that joins real physical and virtual components. The real components may be the power take-off while the virtual ones the numerical models of sea wave and wave energy converter hydrodynamics. This simulation approach has been published with some regularity, however a review of the state-of-the-art has not been found, in particular in the research field dedicated to wave energy converters. Thus, the objective of this paper is to provide the ongoing results of such review, such as the generic testing framework and taxonomy, and their articulation on the simulation of a new oil-hydraulic power take-off concept. In this new concept, different power take-off nominal pressures may be regulated according to different sea states, by changing the hydraulic accumulator charging characteristics. Therefore, this active accumulator is intended to allow an increase on the range of possible Power Take-Off damping forces, thus, better wave energy harvesting performance. The paper results are also intended to support novice and advanced researchers to design simulation approaches in a clear and appropriate manner.
- Oracle for guidance with deep neural networks in reusable launch vehicle landingPublication . Igreja, José; Lemos, Joao MOracles are of paramount importance for Deep Neural Networks training. In this paper, an oracle developed for landing reusable launch vehicles is created from a linearizing feedback control law that can perform a prescribed landing trajectory tracking. The oracle is then used to train a Deep Neural Network that can be used as a guidance system for landing maneuvers. Verification is performed by Monte-Carlo.