Controller for a motor and a method of controlling the motor

Abstract

A pumping apparatus for a jetted-fluid system includes a pump having an inlet connectable to the drain, and an outlet connectable to the return. The pump is adapted to receive the fluid from the drain and jet fluid through the return. The pumping apparatus includes a motor coupled to the pump to operate the pump, a sensor connectable to the power source and configured to generate a signal having a relation to a parameter of the motor, and a switch coupled to the motor and configured to control at least a characteristic of the motor. The pumping apparatus also includes a microcontroller coupled to the sensor and the switch. The microcontroller is configured to generate a derivative value based on the signal, and to control the motor based on the derivative value.

1 . A method of controlling a motor operating a pumping apparatus of a fluid-pumping application, the pumping apparatus comprising a pump having an inlet to receive a fluid and an outlet to exhaust the fluid, and the motor coupled to the pump to operate the pump, the method comprising:
 sensing a motor current;   sensing a motor voltage;   obtaining a derivative value of the motor power based on the sensed voltage and the sensed current;   determining whether the derivative value indicates a condition of the pump; and   controlling the motor to operate the pump based on the condition of the pump.   
     
     
         2 . The method of  claim 1 , further comprising obtaining a power value of the motor power based on the sensed voltage and the sensed current. 
     
     
         3 . The method of  claim 1 , wherein the condition of the pump is an undesired flow of fluid through the pump. 
     
     
         4 . The method of  claim 1 , wherein the pumping apparatus further comprises a voltage sensor and a current sensor, wherein sensing a motor voltage comprises sensing a voltage applied to the motor with the voltage sensor, and wherein sensing a motor current comprises sensing a current through the motor with the current sensor. 
     
     
         5 . A method of controlling a motor operating a pumping apparatus of a jetted fluid system comprising a vessel for holding a fluid, a drain, and a return, the pumping apparatus comprising a pump having an inlet connectable to the drain, and an outlet connectable to the return, the pump adapted to receive the fluid from the drain and jet fluid through the return, and the motor coupled to the pump to operate the pump, the method comprising:
 controlling the motor to operate the pump;   sensing a current of the motor;   calculating a torque of the motor based on the sensed current;   determining whether the torque indicates a condition of the pump; and   further controlling the motor to operate the pump based on the condition of the pump.   
     
     
         6 . The method of  claim 5 , wherein monitoring the operation of the pump further comprises
 sensing a voltage applied to the motor;   determining a speed value related to the motor; and   wherein the calculating a torque is further based on the speed value.   
     
     
         7 . The method of  claim 5 , further comprising
 sensing a speed of the motor; and   wherein the calculating a torque is further based on the sensed speed.   
     
     
         8 . The method of  claim 5 , further comprising
 calculating a value indicative of input power to the motor; and   determining a linear relationship between the torque and the input power to the motor.