Automatic powder selecting control method, system and device for vertical mill classifier

The invention provides an automatic powder selecting control method, system and device for a vertical mill classifier. The automatic powder selecting control method for the vertical mill classifier comprises the following steps that a set target wind pressure value and a set powder fineness target value are input, outlet wind pressure and inlet wind pressure of the vertical mill classifier are collected, a wind pressure difference value between the outlet wind pressure and the inlet wind pressure is calculated, and a running state of a fan is adjusted according to the wind pressure differencevalue and the target wind pressure value; and a powder granularity value is collected, and a state of a frequency converter of the vertical mill classifier is adjusted according to the powder granularity value and the powder fineness target value. The required powder granularity can be automatically obtained according to the set values, steps of manual sampling and adjustment are reduced, in a screening process, the wind