Robust μ-Synthesis and H∞-Loop Shaping Controllers for a Boiler-Turbine Unit

The boiler-turbine unit is a highly nonlinear and strongly coupled complex system. In this paper a robust controller is designed using mu-synthesis and DK-iteration algorithm for a benchmark 160 MW boiler-turbine unit. The structured uncertainty which is considered for this plant is multiplicative input uncertainty, because it is always present. The advantage of this method is that it tries to obtain a controller that optimizes the index mu which determines robust stability and robust performance criteria. In order to evaluate the designed controller, it is compared with another robust controller which just optimizes the H_infin norm of the transfer matrix from exogenous disturbances to exogenous outputs. The simulation results would show robust stability and robust performance of the boiler- turbine system.