Estudo sobre aplicação de controle H2 e H∞ ao conversor CC-CC buck.

Abstract

The Robust Control Theory has its roots on the realization that on practical observations, the control plant is subject to a series of external disturbances which cause problems to its performance and dynamic behavior. On this work it is studied a generic DC-DC Buck Converter subjected to voltage and current disturbances. The control methodology we approach uses the LMI (Linear Matrix Inequalities) Technique, also involving the H2 e H∞ as performance criteria. Firstly it is obtained a model for the Buck Converter on averaged-state-space with and without external disturbances, respectively. Afterwards, it is included a state feed-back controller K which minimizes the perturbation Transfer Function norm through the H2 e H∞ criteria. It was observed that by inserting this controller the system acquires great stability and robustness, causing the asymptotic error to be of very low percentage and also allowing disturbance rejection, even when the perturbation is of high amplitude and frequency. In practical tests result was observed consistent with numerical simulations.