Cooking appliance and method for preconditioning controller terms for cooking operations

Abstract

A cooking appliance includes 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 heating operation. The heating operation includes determining a temperature setpoint for the heating operation, the heating operation including a preheating phase and a feedback controlled cooking phase; directing the at least one heating element based on the determined temperature setpoint over the preheating phase; determining one or more parameters over the preheating phase, the one or more parameters including at least one controller term value for the feedback controlled cooking phase; and directing the at least one heating element according to the one or more determined parameters for a duration of the feedback controlled cooking phase.

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 heating operation, the heating operation comprising:
 determining a temperature setpoint for the heating operation, the heating operation comprising a preheating phase and a feedback controlled cooking phase; 
 directing the at least one heating element based on the determined temperature setpoint over the preheating phase; 
 determining one or more parameters over the preheating phase, the one or more parameters comprising at least one initial controller term value for the feedback controlled cooking phase; and 
 directing the at least one heating element according to the one or more determined parameters for a duration of the feedback controlled cooking phase. 
   
     
     
         2 . The cooking appliance of  claim 1 , wherein determining the one or more parameters over the preheating phase comprises:
 accumulating a plurality of instantaneous integral term values over a duration of the preheating phase.   
     
     
         3 . The cooking appliance of  claim 2 , wherein the feedback controlled cooking phase comprises a closed-loop proportional-integral-derivative (PID) algorithm. 
     
     
         4 . The cooking appliance of  claim 3 , wherein the heating operation further comprises:
 determining an initial integral term value prior to directing the at least one heating element according to the one or more determined parameters, the initial integral term value comprising the plurality of accumulated instantaneous integral term values.   
     
     
         5 . The cooking appliance of  claim 4 , wherein the heating operation further comprises:
 initializing the PID algorithm with the initial integral term value after determining the initial integral term value.   
     
     
         6 . The cooking appliance of  claim 5 , wherein initializing the PID algorithm comprises:
 incorporating an initial derivative term value together with the initial integral term value, the initial derivative term being determined over the duration of the preheating phase.   
     
     
         7 . The cooking appliance of  claim 6 , wherein the initial derivative term value comprises a filtered derivative term value using a filter smoothing factor. 
     
     
         8 . The cooking appliance of  claim 1 , wherein determining the temperature setpoint comprises at least one of:
 receiving an input comprising the temperature setpoint;   retrieving the temperature setpoint based on a food type; or   determining the temperature setpoint based on a selected cooking mode.   
     
     
         9 . The cooking appliance of  claim 1 , wherein directing the at least one heating element based on the temperature setpoint over the preheating phase comprises:
 determining at least one power level for the at least one heating element based on the determined temperature setpoint; and   directing the at least one heating element at the at least one determined power level for a duration of the preheating phase.   
     
     
         10 . A method of operating a cooking appliance, the cooking appliance comprising at least one heating element and a temperature sensor, the method comprising:
 determining a temperature setpoint for a heating operation, the heating operation comprising a preheating phase and a feedback controlled cooking phase;   directing the at least one heating element based on the determined temperature setpoint over the preheating phase;   determining one or more parameters over the preheating phase, the one or more parameters comprising at least one initial controller term value for the feedback controlled cooking phase; and   directing the at least one heating element according to the one or more determined parameters for a duration of the feedback controlled cooking phase.   
     
     
         11 . The method of  claim 10 , wherein determining the one or more parameters over the preheating phase comprises:
 accumulating a plurality of instantaneous integral term values over a duration of the preheating phase.   
     
     
         12 . The method of  claim 11 , wherein the feedback controlled cooking phase comprises a closed-loop proportional-integral-derivative (PID) algorithm. 
     
     
         13 . The method of  claim 12 , further comprising:
 determining an initial integral term value prior to directing the at least one heating element according to the one or more determined parameters, the initial integral term value comprising the plurality of accumulated instantaneous integral term values.   
     
     
         14 . The method of  claim 13 , further comprising:
 initializing the PID algorithm with the initial integral term value after determining the initial integral term value.   
     
     
         15 . The method of  claim 14 , wherein initializing the PID algorithm comprises:
 incorporating an initial derivative term value together with the initial integral term value, the initial derivative term being determined over the duration of the preheating phase.   
     
     
         16 . The method of  claim 15 , wherein the initial derivative term value comprises a filtered derivative term value using a filter smoothing factor. 
     
     
         17 . The method of  claim 10 , wherein determining the temperature setpoint comprises at least one of:
 receiving an input comprising the temperature setpoint;   retrieving the temperature setpoint based on a food type; or   determining the temperature setpoint based on a selected cooking mode.   
     
     
         18 . The method of  claim 10 , wherein directing the at least one heating element based on the temperature setpoint over the preheating phase comprises:
 determining at least one power level for the at least one heating element based on the determined temperature setpoint; and   directing the at least one heating element at the at least one determined power level for a duration of the preheating phase.