Refrigerator

Abstract

A refrigerator according to one embodiment includes an evaporator; a defrosting heater; a temperature sensor; and a controller to control the defrosting heater. The controller is configured to: in response to a defrosting operation starting time arriving, perform a defrosting operation mode including a pre-defrosting cooling mode, a heater operation mode and a post-defrosting cooling mode; perform a continuous operation mode, in which the defrosting heater is continuously on; and when a temperature change rate sequentially increases, decreases and increases again, perform a pulse operation mode, in which the defrosting heater is repeatedly turned on and off.

WHAT IS CLAIMED IS: 
     
         1 . A refrigerator, comprising: 
 an evaporator configured to perform heat exchange;   a defrost heater configured to operate to remove frost formed on the evaporator;   a temperature sensor configured to detect an ambient temperature of the evaporator;   a controller configured to control the defrost heater;   a refrigerating compartment fan; and   a freezer compartment fan,   wherein, in response to a defrosting operation start time point arriving, the controller is configured to perform a defrost operation mode including a pre-defrost cooling mode, a heater operation mode, and a post-defrost cooling mode,   perform a continuous operation mode in which the defrost heater is continuously turned on based on the heater operation mode, and   in response to a change rate of temperature detected by the temperature sensor sequentially increasing, decreasing, and increasing again while performing the continuous operation mode, after a predetermined time elapses, perform a pulse operation mode, in which the defrost heater is repeatedly turned on and off,   in response to the change rate of temperature detected by the temperature sensor being between a first reference value and a second reference value and the temperature detected by the temperature sensor increasing while performing the pulse operation mode, the controller is configured to continuously perform the pulse operation mode,    in response to the change rate of temperature detected by the temperature sensor exceeding the first reference value and the temperature detected by the temperature sensor increasing while performing the pulse operation mode, terminate the pulse operation mode and turn off the defrost heater,   in response to less the change rate of temperature detected by the temperature sensor being than the second reference value and the temperature detected by the temperature sensor increasing while performing the pulse operation mode, terminate the pulse operation mode and perform the continuous operation mode again,   wherein as an amount of frost formed on the evaporator decreases, the controller is configured to decrease turn-on period of the defrost heater in the pulse operation mode.    
     
     
         2 . The refrigerator of  claim 1 , wherein, in response to the change rate of temperature detected by the temperature sensor being between a first reference value and a second reference value while performing the pulse operation mode, the controller is configured to perform the pulse operation mode and sequentially decrease an ON period of the defrost heater. 
     
     
         3 . The refrigerator of  claim 1 , wherein, in response to performing the continuous operation mode again, the controller is configured to control a duration of the continuous operation mode to be less than a duration of the continuous operation mode before the pulse operation mode. 
     
     
         4 . The refrigerator of  claim 1 , wherein, in response to the defrosting operation start time point arriving while performing the normal cooling operation mode, the controller is configured to perform the defrost operation mode including the pre-defrosting cooling mode, the heater operation mode, and the post-defrosting cooling mode, and 
       perform the continuous operation mode of the defrost heater, and the pulse operation mode, in which the defrost heater is repeatedly turned on and off, based on the heater operation mode. 
     
     
         5 . The refrigerator of  claim 1 , wherein the controller is configured to, as the number of opening times of the cooling compartment door increase, decrease a duration of the defrost operation mode. 
     
     
         6 . The refrigerator of  claim 1 , wherein the controller is configured to control a peak temperature arrival time point of the evaporator in response to the continuous operation mode and the pulse operation mode being performed in the defrost operation mode to be later than the peak temperature arrival time point of the evaporator in response to the defrost heater being only continuously turned on in the defrost operation mode. 
     
     
         7 . The refrigerator of  claim 1 , wherein the controller is configured to control an effective defrost in response to the continuous operation mode and the pulse operation mode being performed in the defrost operation mode to be greater than the effective defrost in response to the defrost heater being only continuously turned on in the defrost operation mode. 
     
     
         8 . The refrigerator of  claim 1 , wherein the controller is configured to control a heater OFF time point in response to the continuous operation mode and the pulse operation mode being performed in the defrost operation mode to be later than the heater OFF time point in response to the defrost heater being only continuously turned on in the defrost operation mode. 
     
     
         9 . The refrigerator of  claim 1 , wherein the controller is configured to control a size of an overheat temperature region higher than the defrosting end temperature in response to the continuous operation mode and the pulse operation mode being performed in the defrost operation mode to be less than a size of the overheat temperature region higher than the defrosting end temperature only in response to the defrost heater being only continuously turned on in the defrost operation mode. 
     
     
         10 . The refrigerator of  claim 1 , wherein the controller is configured to control a cooling power supply time point according to a normal cooling operation mode in response to the continuous operation mode and the pulse operation mode being performed in the defrost operation mode to be later than the cooling power supply time point according to a normal cooling operation mode only in response to the defrost heater being only continuously turned on in the defrost operation mode. 
     
     
         11 . The refrigerator of  claim 1 , wherein after the continuous operation mode ends, before the pulse operation mode in which the defrost heater is repeatedly turned on and off, in response to the temperature detected by the temperature sensor reaching the defrosting end temperature, the controller is configured to turn on and off the defrost heater at least once after the defrosting end temperature arrives. 
     
     
         12 . A refrigerator, comprising: 
 an evaporator configured to perform heat exchange;   a defrost heater configured to operate to remove frost formed on the evaporator;   a temperature sensor configured to detect an ambient temperature of the evaporator;   a controller configured to control the defrost heater;   a refrigerating compartment fan; and   a freezer compartment fan,   wherein, in response to a defrosting operation start time point arriving, the controller is configured to perform a defrost operation mode including a pre-defrost cooling mode, a heater operation mode, and a post-defrost cooling mode,   perform a continuous operation mode in which the defrost heater is continuously turned on based on the heater operation mode,    in response to a change rate of temperature detected by the temperature sensor sequentially increasing, decreasing, and increasing again while performing the continuous operation mode, after a predetermined time elapses, perform a pulse operation mode, in which the defrost heater is repeatedly turned on and off,   in response to the change rate of temperature detected by the temperature sensor being between a first reference value and a second reference value and the temperature detected by the temperature sensor increasing while performing the pulse operation mode, the controller is configured to continuously perform the pulse operation mode,    in response to the change rate of temperature detected by the temperature sensor exceeding the first reference value and the temperature detected by the temperature sensor increasing while performing the pulse operation mode, terminate the pulse operation mode and turn off the defrost heater,   in response to the change rate of temperature detected by the temperature sensor being less than the second reference value and the temperature detected by the temperature sensor increasing while performing the pulse operation mode, terminate the pulse operation mode and perform the continuous operation mode again, and   after the continuous operation mode ends, before the pulse operation mode in which the defrost heater is repeatedly turned on and off, in response to the temperature detected by the temperature sensor reaching the defrosting end temperature, the controller is configured to turn on and off the defrost heater at least once after the defrosting end temperature arrives,   wherein as an amount of frost formed on the evaporator decreases, the controller is configured to decrease turn-on period of the defrost heater in the pulse operation mode.    
     
     
         13 . The refrigerator of  claim 12 , wherein the controller is configured to terminate the heater operation mode after performing the turn on and off at least once, and perform the post-defrost cooling mode. 
     
     
         14 . The refrigerator of  claim 12 , wherein the controller is configured to turn off the defrost heater in response to the temperature detected by the temperature sensor reaching the defrosting end temperature during the continuous operation mode. 
     
     
         15 . The refrigerator of  claim 12 , wherein the controller is configured to turn off the defrost heater in response to the temperature detected by the temperature sensor reaching the defrosting end temperature during the continuous operation mode. 
     
     
         16 . A refrigerator, comprising: 
 an evaporator configured to perform heat exchange;   a defrost heater configured to operate to remove frost formed on the evaporator;   a temperature sensor configured to detect an ambient temperature of the evaporator;    a controller configured to control the defrost heater;   a refrigerating compartment fan; and   a freezer compartment fan, wherein, in response to a defrosting operation start time point arriving, the controller is configured to perform a defrost operation mode including a pre-defrost cooling mode, a heater operation mode, and post-defrost cooling mode,   perform a continuous operation mode, in which the defrost heater is continuously turned on, and a pulse operation mode, in which the defrost heater is repeatedly turned on and off based on the defrost operation mode,    in response to a change rate of temperature detected by the temperature sensor sequentially increasing, decreasing, and increasing again while performing the continuous operation mode, after a predetermined time elapses, perform a pulse operation mode, in which the defrost heater is repeatedly turned on and off,   in response to the change rate of temperature detected by the temperature sensor being between a first reference value and a second reference value and the temperature detected by the temperature sensor increasing while performing the pulse operation mode, the controller is configured to continuously perform the pulse operation mode,    in response to the change rate of temperature detected by the temperature sensor exceeding the first reference value and the temperature detected by the temperature sensor increasing while performing the pulse operation mode, terminate the pulse operation mode and turn off the defrost heater,   in response to the change rate of temperature detected by the temperature sensor being less than the second reference value and the temperature detected by the temperature sensor increasing while performing the pulse operation mode, terminate the pulse operation mode and perform the continuous operation mode again,   wherein as an amount of frost formed on the evaporator decreases, the controller is configured to decrease turn-on period of the defrost heater in the pulse operation mode.    
     
     
         17 . The refrigerator of  claim 16 , wherein, in response to performing the continuous operation mode again, the controller is configured to control a duration of the continuous operation mode to be less than a duration of the continuous operation mode before the pulse operation mode. 
     
     
         18.  The refrigerator of  claim 1 , wherein the heater operation mode includes: 
 a first period in which the continuous operation mode is performed, 
 a second period in which the pulse operation mode is performed, 
 a third period in which the defrost heater is turned off after the second period, 
 wherein during the third period, the freezer compartment fan is turned off.