A new decentralized sliding mode observer design for interconnected power systems with unknown and time-varying delay

In this paper, the sliding-mode principles are used to design a decentralized observer for industrial interconnected systems. In the design progress, the interaction between sub-systems has been considered as external disturbances. Also, some factors such as external disturbances have been considered. In this regard, a new sliding mode observer (SMO) for state estimation of interconnected linear systems with unknown time-varying delay, in the presence of unknown inputs has been presented. In the present work, the design procedure is simplified in comparison with the other similar SMO. With an adequate choice of a Lyapunov-Krasovskii functional, the sufficient conditions are obtained in LMIs terms to guarantee asymptotic stability of the state estimation errors. The effectiveness, simplicity and straight-forwardness of the method are shown by the simulation results for a two area power system.