Controller-integrated motor pump

Abstract

A controller-integrated motor pump is disclosed. The motor pump includes: a pump; a motor configured to drive the pump; a control unit configured to control the motor; and a pressure measuring device configured to measure pressure of fluid at a discharge side of the pump. The control unit is mounted on a motor casing. The control unit includes an inverter configured to produce alternating-current power having a frequency within a band that includes frequencies more than or equal to a commercial frequency, a pump controller configured to produce a torque command value for controlling operation of the pump, and a vector controller configured to determine a voltage command value for the inverter based on the torque command value. The motor has a rotor having a plurality of permanent magnets.

1 . A controller-integrated motor pump, comprising:
 a pump;   a motor configured to drive said pump;   a control unit configured to control said motor; and   a discharge-side pressure measuring device configured to measure pressure of fluid at a discharge side of said pump,   wherein said control unit is mounted on a motor casing of said motor, wherein said pump includes
 an impeller secured to a rotational shaft of said motor, and 
 a pump casing in which said impeller is housed, 
   wherein said control unit includes
 an inverter configured to produce alternating-current power having a frequency within a band that includes frequencies more than or equal to a commercial frequency, 
 a pump controller configured to produce a torque command value for controlling operation of said pump, and 
 a vector controller configured to determine a voltage command value for said inverter based on the torque command value, and 
   wherein said motor has a rotor having a plurality of permanent magnets.   
     
     
         2 . The motor pump according to  claim 1 , wherein said pump controller is configured to perform estimated terminal pressure constant control operation in which a target pressure is calculated such that terminal pressure at an outlet of the fluid pressurized by said pump is kept substantially constant regardless of a discharge flow rate of said pump. 
     
     
         3 . The motor pump according to  claim 1 , wherein:
 said control unit further includes a current detector configured to measure three-phase currents to be supplied from said inverter to said motor; and   said vector controller includes
 a three-to-two phase converter configured to convert the three-phase currents into an excitation current and a torque current on a two-phase rotating reference frame, 
 a command converter configured to convert the torque command value into an excitation current command value and a torque current command value, 
 a current controller configured to calculate a d-axis voltage command value for reducing a deviation between the excitation current and the excitation current command value to zero and to calculate a q-axis voltage command value for reducing a deviation between the torque current and the torque current command value to zero, 
 a two-to-three phase converter configured to convert the d-axis voltage command value and the q-axis voltage command value into three-phase voltage command values on a three-phase stationary reference frame, and 
 a phase calculator configured to calculate an angular frequency and a phase of said rotor. 
   
     
     
         4 . The motor pump according to  claim 1 , wherein said motor is an interior permanent magnet motor in which said plurality of permanent magnets are embedded in said rotor. 
     
     
         5 . The motor pump according to  claim 1 , wherein said control unit further includes:
 an electric power calculator configured to calculate an electric power input to said motor and to calculate an electric power input to said inverter;   an electric power integrator configured to integrate values of the electric power calculated by said electric power calculator to determine electric energy per unit time; and   an electric energy display device configured to display the electric energy.   
     
     
         6 . The motor pump according to  claim 5 , wherein said control unit further includes:
 a carbon dioxide emission calculator configured to calculate an amount of carbon dioxide emission based on the electric energy; and   a carbon dioxide emission display device configured to display the amount of carbon dioxide emission.   
     
     
         7 . The motor pump according to  claim 2 , wherein said pump controller includes a memory configured to store a relationship between discharge flow rate and discharge pressure of said pump for maintaining the terminal pressure substantially constant, and said pump controller is configured to calculate the torque command value such that the pressure of the fluid, measured by said discharge-side pressure measuring device, coincides with pressure corresponding to an actual flow rate in accordance with the relationship. 
     
     
         8 . The motor pump according to  claim 1 , wherein said pump controller is configured to perform discharge pressure constant control for maintaining constant discharge pressure of said pump.