Steam temperature observation optimal control method for supercritical unit

The invention discloses a steam temperature observation optimal control method for a supercritical unit. At present, as a point measuring position is excessively near a desuperheating water valve in steam temperature control systems of most of units, an ideal control effect cannot be achieved on introduced advancing steam temperature, and the effect of controlling outlet steam temperature is poorer by using single-stage proportion integration differentiation (PID). The technical scheme adopted by the invention is that a state observation system is introduced into an outlet steam temperature control system to form an outlet steam temperature observation optimal control system. The dynamic procedure of the outlet steam temperature is fit by the state observation system by adopting a mathematical model, and the control is performed through an analog advancing signal and an advancing observation signal. Meanwhile, the steady state and the zero deflection of the outlet steam temperature observation optimal control system are ensured by adopting a static error eliminating system. The mathematical model, the state fitting, the state feedback factor and the control feedback factor of the outlet steam temperature are determined according to the characteristic of the supercritical unit. According to the steam temperature observation optimal control method for the supercritical unit, energy-saving operation of the unit is ensured; the fluctuation range of the outlet steam temperature is greatly reduced when the unit is in an automatic gain control (AGC) state; and the stability of the unit is enhanced.