Generic nonsmooth ℋ∞ output synthesis: Tracking control with application to a coal-fired boiler/turbine unit with input dead zone

The growing share of renewables in the grid power supply has led to the increased agility requirement for the fossil-fired power plants in following the dispatch demand. This has resulted in the increased power plant robust tracking performance requirements characterized by reduced sensitivity to fuel variations and component wear and tear. The ℋ_∞ output tracking control could potentially help in addressing this problem, however the standard ℋ_∞ synthesis produces a tracking error in the plant outputs, thereby degrading the system performance. This error arises due to the fact that in boiler/turbine units, the turbine valve position actuation for manipulating steam flow rate is typically characterized by a dead zone causing small mismatch between the turbine valve command and the actual valve position. To address this deficiency as well as other similar ones arising in control systems due to the actuator nonideality, the generic nonsmooth ℋ_∞ output tracking synthesis is developed and applied to a coal-fired boiler/turbine unit with input dead zone. The simulation results presented support the proposed synthesis.