http://repositorio.ufc.br/handle/riufc/469 2026-04-17T07:43:23Z http://repositorio.ufc.br/handle/riufc/84984 Título: H2Calculator: uma ferramente computacional para análise de sensibilidade e viabilidade econômica da produção de hidrogênio renovável conectada à rede elétrica Autor(es): Sousa, Walter Viana de Abstract: Climate change and the pursuit of decarbonization have received increasing attention, as economic growth can generate significant environmental impacts. In this context, renewable hydrogen emerges as a strategic energy vector, fundamental for the decarbonization of several productive sectors. Renewable hydrogen presents broad applicability, and Brazil, particularly the state of Ceará, has high potential for projects in this area due to its vast availability of renewable resources. However, the feasibility of these ventures critically depends on techno-economic aspects rather than solely on natural factors. Nevertheless, there is a lack of tools capable of providing parameterized economic analyses. In this context, this study aims to propose the H2Calculator, a computational tool developed in Python, designed for preliminary financial analysis in the prospecting of hydrogen production projects connected to the power grid. The tool incorporates electrolysis costs (PEM and alkaline technologies), water supply options (CAGECE, COGERH, and desalinated water), and electricity acquisition in the Free Contracting Environment (ACL), allowing the determination of indicators such as the Levelized Cost of Hydrogen (LCOH), Net Present Value (NPV), Internal Rate of Return (IRR), and discounted payback for the evaluated project. Ten distinct scenarios were simulated using the H2Calculator, four of which were analyzed in detail. In the reference scenario, with an annual production of 1.000.000 kg of H2, PEM technology, water supplied by CAGECE, and an electricity purchase tariff of R$ 163,43/MWh, an LCOH of R$ 23,94/kg was obtained, with a payback period of 23,8 years, as well as positive NPV and IRR values. Comparative analysis among the remaining scenarios revealed that electricity costs are the most influential factor in the LCOH composition, followed by the electrolyzer CAPEX, while water costs had a marginal impact. The model’s consistency was validated through comparison with reference studies. Thus, the H2Calculator is established as a valuable instrument to support decision-making and promote investment in renewable hydrogen. Tipo: Dissertação 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/83946 Título: Sistema de monitoramentopara acapella choice baseado em sensores de frequência oscilatória e níveis de pressão Autor(es): Nascimento, Andreza Costa Abstract: This work presents the development of a respiratory physiotherapy device to monitor the fre- quency of oscillations and the pressure generated during the Oscillatory Positive Expiratory Pressure (OPEP) technique in treating patients with pulmonary pathologies. The Acapella Choice device was used to generate oscillations according to the pressure exerted by the individual during expiration. A signal conditioning circuit was designed to filter and adapt the continuous analog information. The ESP32 microcontroller series was selected for analog-to-digital conversion and signal processing, performing both frequency calculation using the Fast Fourier Transform and pressure calculation. The obtained parameters are displayed to the user, enabling effective and accurate monitoring of the therapy, aiming to optimize treatment outcomes. Tipo: Dissertação 2024-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/83623 Título: Data-driven control of nonlinear systems using dissipativity theory Autor(es): Silva, João Gabriel Napoleão Abstract: In the field of polynomial systems, control design is commonly related to finding Lyapunov conditions in the form of linear matrix inequalities and determining a solution to them through semidefinite programming algorithms. However, the bilinearities inherent to Lyapunov conditions require the use of often suboptimal strategies, such as the D-K iteration, which has no guarantees of solution convergence. In addition, the challenge of some plants that are difficult to model is solved through data collection experiments in order to identify the system. Yet, since the data is subject to disturbances or noise, it hinders the development of a reliable model. In this work, a data-driven approach was used to design control laws without an intermediate identification step and with robustness to data subject to unknown but limited disturbances. Using Lyapunov theory and QSR-dissipation theory, sum-of-squares conditions were constructed to design a control law for polynomial nonlinear systems that guarantees asymptotic stabilization locally around the origin. These conditions were implemented using sum-of-squares programming with the help of SOSTools and Mosek in iterative algorithms without bilinearities and constraints for solution convergence. Finally, the control law and the Lyapunov function were validated using formal verification tools such as Z3Prover to issue a Lyapunov certificate. Keywords: Data-driven control. Nonlinear systems. Dissipativity theory. Tipo: Dissertação 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/83025 Título: Regras de sintonia do preditor de Smith filtrado simplificado para sistemas de primeira ordem com atraso Autor(es): Freitas, Felipe Câmara de Abstract: This paper proposes tuning rules for the Simplified Filtered Smith Predictor for first- order systems with transport delay. These rules are derived from the robust stability condition of the controller and provide the minimum desired parameter to ensure stability and fast rejection of constant disturbances. To achieve this, it is only necessary to provide the system gain, the pole, as well as the time delay along with its maximum uncertainty, and the control gain. Once the analytical form of these rules is obtained, the solutions to the involved transcendental equations are determined through an approximate or numerical method. A program for automatic calculation of the tuning parameter is developed to ease the designer's task. Finally, each rule is tested on the respective first-order systems through simulation and compared with other recent works in the literature. The results show that the proposed rules are effective in determining the value of the filter parameter that is small enough to ensure good performance in disturbance rejection while still ensuring the stability of the control system in the presence of uncertainty in the transport delay value. Tipo: Dissertação 2025-01-01T00:00:00Z