Improved adaptive backstepping sliding mode control for generator steam valves of non-linear power systems

The stability problem of steam valves in a single machine infinite bus system with thyristor controlled series compensation is addressed through the use of an improved adaptive backstepping method based on error compensation. The method combines sliding mode variable structure control, backstepping control and adaptive control. Initially, an excitation control input and error compensation are simultaneously obtained in the design of virtual control by adaptive backstepping and the Lyapunov method. The Lyapunov function is then constituted in stages to achieve subsystem stability, before obtaining a parameter updating law and a non-linear control law for the closed-loop system. The results for both systems show that the improved non-linear backstepping sliding mode variable structure control approach can have four benefits. It can ensure that the system states are bounded, retain the faster stability of power systems, improve the speed of parameter identification and achieve real-time parameter estimation. Finally, a simulation is presented to illustrate both the effectiveness and the feasibility of the improved control approach.