Controle ótimo digital em espaço de estados aplicado a conversores formadores de rede

Abstract

This dissertation presents an optimal control approach to regulate the output vol-tage of an islanded microgrid. This microgrid is fed through a two level voltage source converter with an output LC filter. The main goal of the islanded microgrid is to feed local loads, irrespective their nature, linear, non-linear, balanced or not. In this context, this dissertation presents the system mathematical modelling, performed in the stationary reference frame (αβ0), in state space equations. The converter is con-trolled in voltage mode and pulse width modulation pattern is done using space vector modulation strategy. For the voltage control in the Point of Common Coupling (PCC) multiple digital resonant controller modules in state space are designed. In this way, the digital linear quadratic regulator technique is used to calculate the feedback gains. This method allows to place the closed-loop poles systematically and optimally. The choice of matrices Q and R determine the system dynamics and control effort. These aforementioned matrices ponders the influence of the state variables and the control va-riables, respectively. They are chosen based on the frequency domain analysis, through Bode and Nyquist diagrams. The control implementation is done using the floating pointing digital signal processor TMS320F28335. Moreover, a small scale prototype was developed in laboratory to evaluate the effectiveness of proposed control. So, the experimental results were obtained to illustrate and to validate the operation of the proposed strategy.