Predictive variable structure control and application in power systems

A new predictive variable structure control (PVSC) using the phase plane is proposed and applied to the third-order nonlinear model of the uncertain single machine infinite bus system (SMIBS). Due to the discontinuity of the control switches, chattering in the traditional variable structure control is avoided in PVSC. Two global coordinate transformations are used to change SMIBS into a second-order model. The limits of the system´s uncertainties are used for robustness. The control switches according to the predictive abscissa value of one point in the phase trajectory, which guarantees the trajectory enters a special area in the phase plane within limited time, remains in it and converges to the equilibrium point at an exponential rate. Simulation results show that the system can quickly converge to the original equilibrium point and that the control law is robust.