Navegando por Assunto "Chebyshev theorem"

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Acesso aberto (Open Access)
Performance evaluation of robust parametric control strategies applied on suppression of oscillations effects due to constant power loads in multi-converter buck-buck systems
(Universidade Federal do Pará, 2018-06-11) MARCILLO, Kevin Eduardo Lucas; BARRA JUNIOR, Walter; http://lattes.cnpq.br/0492699174212608
Multi-converter electronic systems are becoming widely used in many industrial applications; therefore, the stability of the cascaded system is a big concern to real-world power supplies applications. Instability in cascaded systems may occur due to the constant power load (CPL), which is a behavior of the tightly regulated converters. CPLs exhibit incremental negative resistance behavior causing a high risk of instability in interconnected converters; therefore, the mitigation of this problem is an important issue in the multiple-stage switched mode power supply design. Thus, it is important to guarantee stability of the whole system. However, some difficulties remains besides the CPL, e.g., non-linearities due to the inductive element and uncertainties due to imprecision of mathematical models and/or variation of nominal values of the discrete elements that compose the DC/DC buck converter. Aiming to evaluate the performance of the proposed robust methodologies in this work to mitigate the instability problem caused by a CPL, several tests were developed by using an experimental plant and Matlab/Simulink, when the multi-converter buck-buck system is subjected a variation of power reference. The results show the improved performance of the proposed methodologies.
Acesso aberto (Open Access)
Projeto de um controlador amortecedor robusto aplicado a um sistema de potência sujeito a incertezas paramétricas
(Universidade Federal do Pará, 2016-03-16) CUNHA, Leiliane Borges; BARRA JUNIOR, Walter; http://lattes.cnpq.br/0492699174212608
This work presents the design of a Stabilizer for the damping of the electromechanical oscillations in electric power systems using robust control technical based on affine parametric uncertainties. These systems are represented by models that have uncertainties in yours parameters, relating to changes in operating conditions. The project methodology is structured to provide a stabilizer that provides the maximum damping to the system, specified by a polytope of characteristic polynomials. For this, it is used poles robust allocation techniques and Chebyshev's theorem, integrated into the solution of linear programming techniques, for the controller design. This technique allows incorporating restrictions on system performance, corresponding to the uncertainties present in the system, making the controller design more robust. Comparisons of the robust controller with a classic controller are made in order to evaluate the results and validate the advantages of the use of controllers designed by the technique proposal. The results and comparisons are performed in simulation environments using MATLAB / SIMULINK software, which allows to model and simulate all kinds of dynamic systems.