This paper solves the load frequency control problem and proposes a new event-triggered sliding-mode control (SMC) algorithm in multi-area interconnected power systems. First, we consider a three-area interconnected power system, and construct its corresponding mathematical model. The prescribed H _∞ , or energy-to-energy, performance is utilized to test the effectiveness of the corresponding disturbance attenuation. Then, an appropriate discrete-time integral switching surface is designed for each subsystem, and the discontinuous controller is designed to guarantee the resulting subsystem asymptotically stable and robust. Using time-delay system analysis technique, the event-triggered scheme, sliding mode dynamics, and the network-induced delays are converted into a network dynamic system with time-varying delays. Thus, corresponding sufficient conditions are derived and an event-triggered SMC law for reaching motion is designed to ensure the reachability of the sliding mode surface in a finite time. Finally, examples and simulations are provided to illustrate the feasibility and the effectiveness of the developed event-triggered SMC scheme.

This note studies the design of sliding mode control (SMC) for discrete-time hybrid stochastic switched systems with repeated scalar nonlinearities. The weighed ℋ _∞ gain performance is considered for the system dynamics to optimize its transient state performance. First, sufficient conditions are given to guarantee the corresponding system is exponentially stable while achieving a desired weighed ℋ _∞ performance. A new switching surface function is constructed by the average dwell time technique and the positive diagonally dominant Lyapunov functional method to further reduce the conservativeness induced by the repeated scalar nonlinearity. Then, the corresponding sliding mode dynamics are obtained and the solvability condition for the desired switching surface function is derived. Furthermore, the synthesis of the proposed SMC law is proposed to force the resulting closed-loop system trajectories onto the pre-specified sliding mode region with a desired level of accuracy. Finally, the feasibility and the effectiveness of the presented new design techniques are illustrated by examples and simulations.

This paper investigates the problem of event-triggered control for a class of uncertain fuzzy time-delay systems based on sliding mode observer design. More specifically, the main purpose is to design an event-triggered mechanism by utilizing the information of system output and observer function. Based on the delay partitioning method and the Lyapunov-Krasovskii function approach, delay-dependent sufficient conditions are proposed to guarantee the overall system, including sliding mode dynamics and error dynamics, to be asymptotically stable with an Hinf performance. Furthermore, an event-triggered sliding mode controller is synthesized to ensure that the systems dynamics can be driven to the sliding region near the equilibrium point in finite time. Finally, a verification example is provided to demonstrate the feasibility and efficiency of the theoretical results presented.

This paper is focused on solving the problems of fault estimation and fault-tolerant control for multiarea power systems with sensor failures. First, the estimations of the system states and fault vectors are determined using an improved sliding-mode observer technique. Moreover, a derivative gain and a proportional gain are introduced to design the resultant sliding-mode observer more freely, and a discontinuous input is given to reduce the impact of sensor faults and aggregated uncertainties. Then, based on the obtained state estimates, an integral-type sliding-mode control scheme against faults and disturbances is proposed to ensure that the resultant fault system is asymptotically stable, from which each subsystem states in the multiarea power system can be driven onto the designed sliding-mode surfaces in both the state estimation and error estimation spaces. Finally, a three-area power system is simulated to validate the feasibility of the developed fault-tolerant control scheme.