Optimization and H∞ Performance Analysis for Load Frequency Control of Power Systems With Time-Varying Delays

Abstract

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With the development and expansion of the power grid, the load frequency control (LFC) scheme receives sensor signals and outputs control signals through an open communication network with a mass of data and extensive information exchange, which may introduce constant, and time-varying delays. This paper considers the optimization and H∞ performance problem for LFC of power systems with time-varying delays. Some improved criteria for guaranteeing the stability and H∞ performance of the closed-loop system with unknown external load disturbances via the Lyapunov stability theory application. An unique delay-dependent proportional-integral (PI) controller and an optimized PI controller are designed for a specified H∞ performance index and set, respectively. The criteria proposed in this paper are based on linear matrix inequalities (LMIs), which can be easily solved by the MATLAB LMI-Toolbox. Finally, in case studies, the effectiveness of our method is demonstrated.

Keywords

• optimization and control
• power system
• smart grids
• H ∞ control
• load frequency control
• time delays