Reachability of the sliding mode control for multimachine power systems

Abstract

This paper presents conditions of reachability of a switching plane for the sliding mode control of phase shifters in multimachine power systems. Sliding mode controllers are usually synthesized so as to satisfy only the existence condition of a sliding mode. However, there is the border of an asymptotically stable region and a system state cannot reach a switching plane unless a state at the beginning of control (initial state) exists in that region. Hence, reachability is defined as an asymptotic stability of the initial state. A sufficient condition to reach onto a switching plane is given by an energy-type Lyapunov function. It is described by control parameters that are introduced to find required control gains rather than feedback gains themselves. This allows us to straightforwardly evaluate an asymptotic stability. A phase-shift control system is numerically tested in a 2-machine 1-infinite-bus power system. The simulation results show that the improved control system offers faster transient stability and achieves the reachability of a switching plane. © 2000 Scripta Technica, Electr Eng Jpn, 131(3): 43–50, 2000