Global Finite-Time Stabilization for a Class of Uncertain High-Order Nonlinear Systems

This paper addresses the problem of global finite-time stabilization by state feedback for a class of high-order nonlinear systems under weaker condition. By using the methods of adding a power integrator, a continuous state feedback controller is successfully constructed to guarantee the global finite-time stability of the resulting closed-loop system. A simulation example is provided to illustrate the effectiveness of the proposed approach

Robustness of Homogeneous Systems with Respect to Time-Varying Perturbations

The problem of stability robustness with respect to time-varying perturbations of a given frequency spectrum is studied applyinghomogeneity framework. The notion of finite-time stability over time intervals of finite length, i.e. short-finite-time stability, isintroduced and used for that purpose. The results are applied to analyze the Super-Twisting algorithm behavior under sometime-varying perturbations, and to demonstrate some robustness properties of the three-tank system. Some simulation examplesillustrate these robustness properties

Adaptive Observer-Based Decentralized Scheme for Robust Nonlinear Power Flow Control Using HPFC

This paper investigates the robust decentralized nonlinear control of power flow in a power system using a new configuration of UPFC. This structure comprises two shunt converters and one series capacitor called as hybrid power flow controller (HPFC). A controller is designed via control Lyapunov function (CLF) and adaptive observer to surmount the problems of stability such as tracking desired references, robustness against uncertainties, rejecting the disturbances, and remote data estimation. The suggested control scheme is decentralized using adaptive observer to estimate the non-local varying parameters of the system. Stability of the closed loop system is proved mathematically using Lyapunov stability theorem. Performance of the proposed finite-time controller (FT-C) is compared to another suggested exponentially convergent nonlinear controller (ECN-C) and a conventional PI controller (PI-C). Settling time of the state variables are diminished to a known little time by FT-C in comparison with ECN-C and PI-C. Simulation results are given to validate the proposed controllers. Effects of model uncertainties such as parameter variation in the transmission line and the converters are studied and properly compensated by the proposed controllers. The impact of the control gain and the communication time-delay is shown using the Bode diagram analysis