A design of robust two-degree-of-freedom boiler-turbine control systems using H∞ optimization method

This paper deals with the robust two-degree-of-freedom multivariable control system using H_∞ optimization method which can achieve the robust stability and the robust performance property simultaneously. The feedback controller is designed using H_∞ optimization method for mixed sensitivity function. The feedforward controller is designed using H₂ optimization method to minimize the error of both the transfer function of the optimal model and the overall transfer function. The feedback controller can obtain the robust stability property. The feedforward controller can obtain the robust performance property under modelling error. The robust two-degree-of-freedom multivariable control system is applied to the nonlinear multivariable boiler-turbine system. The boiler turbine system is analyzed at various operation points. The validity of the proposed method is verified in comparison with the LQG/LTR design method