Cooking appliance and method of operating the same incorporating adjusted controller gain values

Abstract

A method of operating a cooking appliance includes retrieving a default set of controller gain values for a feedback controlled heating operation, the default set of controller gains including a default proportional gain value, a default integral gain value, and a default derivative gain value; directing the at least one heating element according to the default set of controller gain values; detecting a food event; determining a total amount of change in a power level of the at least one heating element in response to detecting the food event; determining an adjusted set of controller gain values; and directing the at least one heating element according to the adjusted set of controller gain values.

What is claimed is: 
     
         1 . A cooking appliance comprising:
 at least one heating element to selectively supply heat to a cookware item;   a temperature sensor configured to selectively monitor a temperature of the cookware item; and   a controller operably connected with the at least one heating element and the temperature sensor, the controller configured to perform a feedback controlled heating operation, the feedback controlled heating operation comprising:
 retrieving a default set of controller gain values for the feedback controlled heating operation, the default set of controller gain values comprising a default proportional gain value, a default integral gain value, and a default derivative gain value; 
 directing the at least one heating element according to the default set of controller gain values; 
 detecting a food event while directing the at least one heating element according to the default set of controller gain values; 
 determining a total amount of change in a power level of the at least one heating element in response to detecting the food event; 
 determining an adjusted set of controller gain values in response to determining the total amount of change in the power level of the at least one heating element; and 
 directing the at least one heating element according to the adjusted set of controller gain values. 
   
     
     
         2 . The cooking appliance of  claim 1 , wherein detecting the food event comprises:
 determining that a power level of the at least one heating element has changed by a predetermined minimum amount within a predetermined length of time.   
     
     
         3 . The cooking appliance of  claim 2 , wherein determining the total amount of change in the power level of the at least one heating element comprises:
 determining a power level difference between a maximum power level value achieved as a result of the food event and a power level value immediately preceding the food event.   
     
     
         4 . The cooking appliance of  claim 3 , wherein the feedback controlled heating operation further comprises:
 determining that the total amount of change in the power level of the at least one heating element is outside of a predetermined range.   
     
     
         5 . The cooking appliance of  claim 4 , wherein the predetermined range comprises between 10 levels and 15 levels. 
     
     
         6 . The cooking appliance of  claim 2 , wherein the feedback controlled heating operation comprises a closed-loop proportional-integral-derivative (PID) algorithm, and wherein the power level of the at least one heating element is dictated by an output of the PID algorithm. 
     
     
         7 . The cooking appliance of  claim 2 , wherein determining the adjusted set of controller gain values comprises:
 determining an adjusted derivative gain value based on the total amount of change in the power level of the at least one heating element.   
     
     
         8 . The cooking appliance of  claim 7 , wherein determining the adjusted derivative gain value comprises:
 determining a ratio of an expected total amount of change in the power level of the at least one heating element against the determined total amount of change in the power level of the at least one heating element; and   multiplying the determined ratio with the default derivative gain value.   
     
     
         9 . The cooking appliance of  claim 8 , wherein the expected total amount of change in the power level of the at least one heating element is based on empirical data. 
     
     
         10 . The cooking appliance of  claim 7 , wherein the adjusted derivative gain value is stored within the cooking appliance. 
     
     
         11 . A method of operating a cooking appliance, the cooking appliance comprising at least one heating element and a temperature sensor, the method comprising:
 retrieving a default set of controller gain values for a feedback controlled heating operation, the default set of controller gain values comprising a default proportional gain value, a default integral gain value, and a default derivative gain value;   directing the at least one heating element according to the default set of controller gain values;   detecting a food event while directing the at least one heating element according to the default set of controller gain values;   determining a total amount of change in a power level of the at least one heating element in response to detecting the food event;   determining an adjusted set of controller gain values in response to determining the total amount of change in the power level of the at least one heating element; and   directing the at least one heating element according to the adjusted set of controller gain values.   
     
     
         12 . The method of  claim 11 , wherein detecting the food event comprises:
 determining that a power level of the at least one heating element has changed by a predetermined minimum amount within a predetermined length of time.   
     
     
         13 . The method of  claim 12 , wherein determining the total amount of change in the power level of the at least one heating element comprises:
 determining a power level difference between a maximum power level value achieved as a result of the food event and a power level value immediately preceding the food event.   
     
     
         14 . The method of  claim 13 , further comprising:
 determining that the total amount of change in the power level of the at least one heating element is outside of a predetermined range.   
     
     
         15 . The method of  claim 14 , wherein the predetermined range comprises between 10 levels and 15 levels. 
     
     
         16 . The method of  claim 12 , wherein the feedback controlled heating operation comprises a closed-loop proportional-integral-derivative (PID) algorithm, and wherein the power level of the at least one heating element is dictated by an output of the PID algorithm. 
     
     
         17 . The method of  claim 12 , wherein determining the adjusted set of controller gain values comprises:
 determining an adjusted derivative gain value based on the total amount of change in the power level of the at least one heating element.   
     
     
         18 . The method of  claim 17 , wherein determining the adjusted derivative gain value comprises:
 determining a ratio of an expected total amount of change in the power level of the at least one heating element against the determined total amount of change in the power level of the at least one heating element; and   multiplying the determined ratio with the default derivative gain value.   
     
     
         19 . The method of  claim 18 , wherein the expected total amount of change in the power level of the at least one heating element is based on empirical data. 
     
     
         20 . The method of  claim 17 , wherein the adjusted derivative gain value is stored within the cooking appliance.