Structured Low Order Controller Design for H_∞ Loop Shaping Method and Application in Water Level Control of Steam Generators

To overcome the difficulty in weight selection and high order of the derived controller in standard H∞ loop shaping design,a structured low order controller design for H loop shaping method was proposed.The design method combines structured low order weight optimization with static H synthesis.Once the order and structure of controller together with control points coordinate of the bounds of shaped plant singular value are given,the linear matrix inequality based iterative optimization can be adopted to design the controller with desired control performance index and maximum robust stability margin.Second order robust controller was designed for steam generator water level plant.The comparative simulations of step response for level set point and steam flow rate at different power level with the proposed scheme,active disturbances rejection control algorithm and double PI control one were performed.Simulation results show that the proposed control system achieves good performance and its robust stability is better than the other two ones.