The complexity and variability of coal quality is the main factor affecting the control quality of units.Through mechanism analysis and debugging

it was found that the change of coal grindability affects the output of the coal mill significantly

which leads to change of the characteristics of the controlled object of pulverizing system

and then affects the closed-loop control characteristics of the main control loop of boiler side in coordinated control system. Through characteristics recognition of coal feed rate and throttle pressure signals

the membership degree of dynamic characteristics was determined for pulverizing system belonging to inertia

inertia plus pure delay and non-minimum phase

based on which the parameters of controller were flexibly adjusted to realize intelligent power generation control according to the expert database in intelligent DCS. The simulation and field debugging results show that

the optimization strategy can significantly improve the control quality of the main parameters of the unit when the coal grindability changes

and can provide technical support for thermal power units to improve the adaptability to coal quality.