Unified Smith predictor and H∞ loop shaping for load frequency control with delay

A fixed-structure controller based on robust H∞ loop shaping for load frequency control (LFC) of two area system having communication delay is designed in this paper. The delay complicates the design and implementation of the controller. Unified Smith Predictor (USP) has been analysed to convert delayed plant to a delay free augmented plant. A robust controller is designed for the augmented plant by formulating an optimisation problem using H∞ loop shaping performance condition and is solved by using genetic algorithm (GA). It is shown that designed controller has simpler structure than conventional H∞ loop shaping controller and ensures stable dynamic performance.