Wide-area damping robust control strategy based on integral sliding mode control

During the design of integral sliding mode surface by use of hybrid H2/H∞ robust control theory, the conservatism is stemmed from utilizing a common Lyapunov matrix only, in the meanwhile, the uncertainty caused by unknown system structure and operating point variation is not adequately considered in this method. In allusion to it, a wide-area integral sliding mode control method, which can reduce both conservatism and uncertainty, is proposed. A sliding mode switching function in integral form for the proposed method is designed, and the buffeting is weakened by boundary layer method. During the design of sliding mode surface, firstly the Lyapunov matrix in H2/H∞ control theory is separated from system matrix; secondly for H2 control and H∞ control the Lyapunov matrices, which can make the constraints at polyhedral vertexes established, are calculated respectively and these Lyapunov matrices are taken as the feedback gain matrices in integral sliding mode control; finally an integral sliding mode controller based on weakened conservatism and reduced uncertainty is obtained. The correctness and effectiveness of the proposed method are verified by simulation results of IEEE 4-machine 2-area system.