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U.S. Department of Energy
Office of Scientific and Technical Information

Decentralized adaptive control for large-scale interconnected systems with applications to power systems

Thesis/Dissertation ·
OSTI ID:6285684

Two Model reference decentralized adaptive control algorithms for large-scale interconnected systems with multi-input and multi-output subsystems and subjected to bounded disturbances have been developed in this thesis. The adaptation mechanism for adjusting the controller parameters has been determined through constructing a suitable Lyapunov function for the decoupled subsystems. Stability of the adaptive system equations, which are interconnected, has been analyzed using a weighted-sum scalar Lyapunov function approach. Stability results show that, the output tracking error and the controller parameters are bounded provided certain conditions on the subsystem matrices are satisfied. The first algorithm ensures asymptotic stability to a bounded residual set if the closed-loop transfer matrices of all decoupled subsystems are Strict Positive Real (SPR) for some feedback transfer matrices. The size of the residual set is a function of the interconnection and the disturbance bounds. The second algorithm does not require the subsystem transfer matrices to be strict positive real and guarantees the convergence of the tracking error and the controller parameters to a bounded residual set of a size which depends on the interconnection and the disturbance bounds and some design parameters. When the interconnections and the disturbances are not present, the output tracking error resulting from the first algorithm approaches zero asymptotically. On the other hand, the second algorithm yields a bounded tracking error of a bound which depends on the choice of design parameters. Applications of both decentralized adaptive control algorithms to enhance the damping performance of the electromechanical modes of a multi-machine power system are presented. A typical three-machine power system subjected to a three-phase short circuit is used as an illustrative example.

Research Organization:
Pittsburgh Univ., PA (USA)
OSTI ID:
6285684
Country of Publication:
United States
Language:
English