arXiv subjects

L. V. Fiorio

Publications and source records attributed to L. V. Fiorio.

3 recordsLinked to original sources

arXiv2023

Virtual reference feedback tuning with robustness constraints: A swarm intelligence solution

The simplified modeling of a complex system allied with a low-order controller structure can lead to poor closed-loop performance and robustness. A feasible solution is to avoid the necessity of a model by using data for the controller design. The Virtual Reference Feedback Tuning (VRFT) is a data-driven design method that only requires a single batch of data and solves a reference tracking problem, although with no guarantee of robustness. In this work, the inclusion of an $\mathcal{H}_{\infty}$ robustness constraint to the VRFT cost function is addressed. The estimation of the $\mathcal{H}_{\infty}$ norm of the sensitivity transfer function is extended to maintain the one-shot characteristic of the VRFT. Swarm intelligence algorithms are used to solve the non-convex cost function. The proposed method is applied in two real-world inspired problems with four different swarm intelligence algorithms, which are compared with each other through a Monte Carlo experiment of 50 executions. The obtained results are satisfactory, achieving the desired robustness criteria.

eess.SY↗

arXiv2021

Data-driven estimation of system norms via impulse response

This paper proposes a method for estimating the norms of a system in a pure data-driven fashion based on their identified Impulse Response (IR) coefficients. The calculation of norms is briefly reviewed and the main expressions for the IR-based estimations are presented. As a case study, the $\mathcal{H}_{1}$, $\mathcal{H}_2$, and $\mathcal{H}_{\infty}$ norms of the sensitivity transfer function of five different discrete-time closed-loop systems are estimated for a Signal-to-Noise-Ratio (SNR) of 10 dB, achieving low percent error values if compared to the real value. To verify the influence of the noise amplitude, norms are estimated considering a wide range of SNR values, for a specific system, presenting low Mean Percent Error (MPE) if compared to the real norms. The proposed technique is also compared to an existing state-space-based method in terms of $\mathcal{H}_{\infty}$, through Monte Carlo, showing a reduction of approximately 48 % in the MPE for a wide range of SNR values.

eess.SY↗

arXiv2021

Switched Control Applied to a Totem-Pole Bridgeless Rectifier for Power Factor Correction

The wide range of operation of bridgeless rectifiers requires a control technique that guarantee robustness. Linear Power Factor Correction (PFC) control techniques, although effective, cannot guarantee such robustness. Nonlinear techniques such as one cycle control are more robust, but other options should be explored. In this work, an affine model is obtained for a Totem-Pole Bridgeless Rectifier (TPBR). An extension to an existing switched control design technique is presented in order to achieve PFC in a robust fashion for the TPBR. Simulations with nonideal components and distorted grid voltage show a precise, fast and robust performance of the switched controller. The effective reference following of the proposed method allows the user to define a current reference waveform that prioritize THD or power factor, depending on the application and norm requirements.

eess.SY↗