Abstract: Power plant superheated steam temperature system is characterized by large inertia and large lag. Usually spray system is applied to form a cascade control system and cascade PID scheme is usually employed to control superheated steam temperature. The spray valve is subject to physical constraints so that actuator saturation happens because of the set point computed by the outer loop controller. The method of cascade model predictive control was applied. Constrained model predictive control(CMPC) was used to handle constraints and obtain optimal solution with system satisfying the corresponding constraints. In addition, simulation of superheated steam system was realized.

Key words: cascade control, predictive control, superheated steam temperature system, constraint