In order to solve control problems in AC-motor feed water pump and variable-frequency feed water pump parallel operation

this paper proposed a new control scheme.Through on-site data collection and data analysis

the functional relationship between pump scoop control instruction and pump speed was respectively obtained.Moreover

according to the proportion law of pumps and fans

the functional relationship between the pump scoop control instruction and variable-frequency control instruction was obtained.On the basis of this function relationship

a new control scheme was designed and had been applied in practical engineering successfully.The scheme this paper put forward may serve as a reference for designing the control strategy in similar retrofit of the electrical feed water pumps.