부산대학교 도서관

This paper proposes a novel nonlinear multi-loop control method for the coordinated control of the Unified Power Flow Controller (UPFC) using high gain state and perturbation observers (HGSPO). The UPFC is decoupled into four independent subsystems. The optimal output feedback control of each subsystem is achieved with the estimates of states and perturbations obtained by the HGSPO. A four-loop nonlinear observer-based control (NOC) configuration is adopted to achieve the coordinated control of UPFC. The design of the four-loop NOC does not require any accurate system information and it is robust to external disturbances. Simulation studies have been carried out to verify the superior active and reactive power control ability of the four-loop NOC in comparison with the conventional vector control (VC) scheme.