Abstract：In response to the problem of slow response speed of main steam pressure in the coordinated control

system of thermal power units，the control effect of the coordinated control system was improved by blowing out

some of the stored powder in the pulverizing system. Based on the traditional milling system model，considering the influence of primary air flow，a milling system model based on primary air flow was established，which has been verified to reflect the dynamic characteristics of primary air flow on the milling system. On the basis of the

improved model of milling system，a primary air flow dynamic compensation system was designed，which

combined with the original coordinated control system of the unit to form a coordinated control system based on the primary air flow dynamic compensation，which realized the utilization of powder storage inside the coal mill. The simulation results show that the designed system effectively utilizes the stored powder in the coal mill by changing the primary air flow rate. On the premise of ensuring rapid response to load changes，it has a good control effect on the main steam pressure，improves the response speed of the main steam pressure，and improves the control quality of the coordinated control system.

      Key words：modeling of milling systems considering primary air flow；dynamic compensation of primary air

flow；coordinate control system optimization