The different variable structure control strategy applied in power system load frequency control

For single area power system, a variable structure load frequency controller based on constant reaching law is proposed. Firstly, the original system is converted into standard type through the elementary transformation matrix, and the switching surface is designed based on the standard type, at the same time, the switching function is selected properly by using the pole assignment method which assure the sliding mode is stable. Secondly, the sliding mode controller is designed by using the constant reaching law, which can assure the hitting condition is satisfied. Finally, the power system model is used by simulation considering the ideal working condition and with generation rate constraint. The simulation results illustrate the effectiveness and robust of the designed controller.