Method and system for identifying and controlling a centrifugal pump

Abstract

The invention relates to a method and a system for controlling a centrifugal pump ( 1 ) actuated by an electric motor ( 2 ). The control method comprises: a first step of selecting a speed and of controlling the variable speed drive ( 3 ) in order to apply said speed to the electric motor ( 2 ), a second step of controlling the solenoid valve ( 6 ) over the whole of its operating range at said selected speed, a third step of measuring the pressure and the flow rate of the fluid flowing in the pumping circuit and of measuring the electric power supplied to the motor for each operating point of the solenoid valve ( 6 ), a fourth step of determining, for said selected speed, the pressure curve as a function of the flow rate and the curve of the power supplied as a function of the flow rate.

1 . Method for controlling a centrifugal pump ( 1 ) included in a pumping circuit controlled by a control system, said control system comprising:
 a variable speed drive ( 3 ) and an electric motor ( 2 ) controlled by the variable speed drive so as to actuate the centrifugal pump,   a measurement or an estimate by the variable speed drive of the mechanical power supplied to the electric motor,   a solenoid valve ( 6 ) designed to control the pumping circuit,   a pressure sensor ( 4 ) designed to measure the pressure of the fluid flowing in the pumping circuit,   a flow-rate sensor ( 5 ) designed to measure the flow rate of the fluid flowing in the pumping circuit,   a control and processing unit ( 30 ),   
       said method being characterized in that it comprises a phase of identification of the centrifugal pump ( 1 ), carried out by the control and processing unit ( 30 ), prior to the normal operation of said centrifugal pump, said identification phase comprising:
 a first step of selecting a speed and of controlling the variable speed drive ( 3 ) in order to apply said speed to the electric motor ( 2 ), 
 a second step of controlling the solenoid valve ( 6 ) over the whole of its operating range at said selected speed, 
 a third step of measuring the pressure and the flow rate of the fluid flowing in the pumping circuit and of measuring the electric power supplied to the motor for each operating point of the solenoid valve ( 6 ), 
 a fourth step of determining, for said selected speed, the pressure curve as a function of the flow rate and the curve of the power supplied as a function of the flow rate. 
 
     
     
         2 . Control method according to  claim 1 , characterized in that the second step, the third step and the fourth step are carried out for several speeds applied to the electric motor ( 2 ). 
     
     
         3 . Control method according to  claim 1 , characterized in that, for a selected speed, the third step and the fourth step are carried out for each operating point of the solenoid valve ( 6 ). 
     
     
         4 . System of controlling a centrifugal pump ( 1 ) included in a pumping circuit, said control system comprising:
 a variable speed drive ( 3 ) and an electric motor ( 2 ) controlled by the variable speed drive so as to actuate the centrifugal pump ( 1 ),   a measurement or an estimate by the variable speed drive of the mechanical power supplied to the electric motor,   a solenoid valve ( 6 ) designed to control the pumping circuit,   a pressure sensor ( 4 ) designed to measure the pressure of the fluid flowing in the pumping circuit,   a flow-rate sensor ( 5 ) designed to measure the flow rate of the fluid flowing in the pumping circuit,   a control and processing unit ( 30 ),   
       said system being characterized in that the control and processing unit ( 30 ) comprises a module for identifying the centrifugal pump, said module being activated prior to the normal operation of said centrifugal pump, and in that said identification module comprises:
 means for selecting a speed and means for controlling the variable speed drive ( 3 ) in order to apply said speed to the electric motor ( 2 ), 
 means for determining the power supplied to the electric motor ( 2 ) for said selected speed, 
 means for controlling the solenoid valve ( 6 ) over the whole of its operating range at said selected speed, 
 means for retrieving the measurements of the pressure and of the flow rate of the fluid flowing in the pumping circuit for each operating point of the solenoid valve ( 6 ), 
 means for determining, for said selected speed, the pressure curve as a function of the flow rate and the curve of the power supplied as a function of the flow rate. 
 
     
     
         5 . Control system according to  claim 4 , characterized in that the control and processing unit ( 30 ) is included in the variable speed drive ( 3 ). 
     
     
         6 . Control method according to  claim 2 , characterized in that, for a selected speed, the third step and the fourth step are carried out for each operating point of the solenoid valve ( 6 ).