Contribuições à utilização de observadores de estados em projetos de controladores aplicados em sistemas de geração distribuída

Abstract

This work presents the controller design and applied state observers to a three-phase distributed generation system, containing a two-level electronic power converter connected to the electrical grid through an LCL filter. The control strategy is developed by state feedback and uses different state observers methodologies. The system is modelled in the synchronous reference frame, allowing integral action to mitigate errors in steady state for active and reactive powers and d.c. voltage controls. State feedback gains are obtained by the Quadratic Linear Regulator methodology, and, based on Bryson’s rule, procedures for tuning the controllers are proposed and analysed based on the dynamic response of the system. In addition, different methods for designing state observers are evaluated to reduce the number of sensors needed in the connection filter. The state observers studied in this document are: (i) Full order; (ii) reduced order; (iii) extended;(iv)unknown input. Simulation results are presented to show the effectiveness of the control strategy, as well as, to verify the state estimators behaviour used in this work.