An Adaptive Load Frequency Control Based on Sliding Mode Control and Disturbance Observer

To maintain the stability of the power system, the load frequency controller design is one critical task. In this paper, an adaptive disturbance observer-based sliding mode control (ADOB-SMC) is constructed, which relaxes the requirement for having prior knowledge of the disturbance by introducing a disturbance observer. To achieve better control performance, the adaptive constant reaching law is integrated into the proposed ADOB-SMC. The proposed controller can effectively regulate the frequency deviation to zero, and produce less overshoots compared with the conventional proportional-integral (PI) controller-based methods. In addition, the proposed ADOB-SMC controller has less dependence on prior knowledge on the system disturbance than the traditional sliding mode control (SMC). Considering the real situation in Western Australia (WA), two cases are constructed to test the performance of the proposed methods. The performance of the proposed controller is verified by simulation studies using MATLAB/Simulink.