Dishwashing appliance with decision making via sensor circuit

Abstract

A method of operating a dishwashing appliance includes activating a pump for a predefined self-calibration time by supplying electrical power from a power supply to a motor of the pump. The method also includes monitoring, with the sensor circuit, electrical power between the power supply and the motor while the pump is activated for the predefined self-calibration time. The method further includes determining, based on the monitored electrical power, a motor type of the motor and selecting a set of control parameters corresponding to the determined motor type of the motor. The method also includes activating the pump according to the selected set of control parameters during at least one cycle of the dishwashing appliance.

What is claimed is: 
     
         1 . A method of operating a dishwashing appliance, the dishwashing appliance comprising a tub defining a wash chamber therein for receipt of articles for washing, a sump positioned at a bottom of the wash chamber for receiving fluid from the wash chamber, a pump in fluid communication with the wash chamber and the sump, the pump comprising a motor, and a sensor circuit, the method comprising:
 activating the pump for a predefined self-calibration time by supplying electrical power from a power supply to the motor of the pump;   monitoring, with the sensor circuit, electrical power between the power supply and the motor while the pump is activated for the predefined self-calibration time;   determining, based on the monitored electrical power, a motor type of the motor;   selecting a set of control parameters corresponding to the determined motor type of the motor; and   activating the pump according to the selected set of control parameters during at least one cycle of the dishwashing appliance.   
     
     
         2 . The method of  claim 1 , wherein the step of monitoring electrical power comprises monitoring electrical current to the motor, further comprising comparing the monitored electrical current to the motor against a threshold, and wherein the step of determining the motor type comprises determining a first motor type when the monitored electrical current to the motor is greater than the threshold and determining a second motor type when the monitored electrical current to the motor is less than the threshold. 
     
     
         3 . The method of  claim 2 , wherein comparing the monitored electrical current to the motor against the threshold comprises comparing a plurality of instantaneous values of the current to the motor against the threshold during the self-calibration time. 
     
     
         4 . The method of  claim 1 , wherein the step of monitoring electrical power comprises monitoring back electromotive force from the motor. 
     
     
         5 . The method of  claim 1 , wherein the set of control parameters comprises a conversion table of motor speed settings to electrical switch settings. 
     
     
         6 . The method of  claim 5 , wherein the electrical switch settings are triode settings. 
     
     
         7 . The method of  claim 1 , wherein the sensor circuit comprises a shunt resistor, an operational amplifier, an amplifier, and a microcontroller. 
     
     
         8 . The method of  claim 1 , wherein the pump is a circulation pump. 
     
     
         9 . The method of  claim 1 , wherein the pump is a drain pump. 
     
     
         10 . A dishwashing appliance, comprising:
 a tub defining a wash chamber therein for receipt of articles for washing;   a sump positioned at a bottom of the wash chamber for receiving fluid from the wash chamber;   a pump in fluid communication with the wash chamber and the sump, the pump comprising a motor;   a sensor circuit; and   a controller, the controller configured for:
 activating the pump for a predefined self-calibration time by supplying electrical power from a power supply to the motor of the pump; 
 monitoring, with the sensor circuit, electrical power between the power supply and the motor while the pump is activated for the predefined self-calibration time; 
 determining, based on the monitored electrical power, a motor type of the motor; 
 selecting a set of control parameters corresponding to the determined motor type of the motor; and 
 activating the pump according to the selected set of control parameters during at least one cycle of the dishwashing appliance. 
   
     
     
         11 . The dishwashing appliance of  claim 10 , wherein the step of monitoring electrical power comprises monitoring electrical current to the motor, wherein the controller is further configured for comparing the monitored electrical current to the motor against a threshold, and wherein the step of determining the motor type comprises determining a first motor type when the monitored electrical current to the motor is greater than the threshold and determining a second motor type when the monitored electrical current to the motor is less than the threshold. 
     
     
         12 . The dishwashing appliance of  claim 11 , wherein comparing the monitored electrical current to the motor against the threshold comprises comparing a plurality of instantaneous values of the current to the motor against the threshold during the self-calibration time. 
     
     
         13 . The dishwashing appliance of  claim 10 , wherein the step of monitoring electrical power comprises monitoring back electromotive force from the motor. 
     
     
         14 . The dishwashing appliance of  claim 10 , wherein the set of control parameters comprises a conversion table of motor speed settings to electrical switch settings. 
     
     
         15 . The dishwashing appliance of  claim 14 , wherein the electrical switch is a triode. 
     
     
         16 . The dishwashing appliance of  claim 10 , wherein the sensor circuit comprises a shunt resistor, an operational amplifier, an amplifier, and a microcontroller. 
     
     
         17 . The dishwashing appliance of  claim 10 , wherein the pump is a circulation pump. 
     
     
         18 . The dishwashing appliance of  claim 10 , wherein the pump is a drain pump.