Adaptive backstepping composite nonlinear control for utility boiler-turbine units

The boiler-turbine unit is the most popular form of fossil-fuel power generation units in China. To achieve expected operation performance, the boiler-turbine control system is necessary as the upper level control system to ensure the boiler and the turbine run as a whole. Based on adaptive backstepping and composite nonlinear feedback theories, this paper presents an efficient control scheme to simplify control laws, improve load adaptability of boiler-turbines in wide operation range and limit control actions. The design process of the scheme includes model preprocessing, adaptive backstepping controller design, composite nonlinear feedback control law construction, etc. A practical nonlinear model of a 500 MW coal-fired boiler-turbine unit is used to test the efficiency of the proposed scheme in different conditions.