Refrigerator and control method of the same

Abstract

The invention provides a refrigerator having a compressor, the refrigerator including: a motor driving the compressor; a motor driver supplying power to the motor; and a controller outputting a control signal corresponding to a second command speed to the motor driver, and outputting a control signal corresponding to a first command speed which is higher than the second command speed to the motor driver when a driving on/off ratio of the motor driver is maintained below a given reference driving on/off ratio for a given reference period. Accordingly, it is an aspect of the present invention to provide a refrigerator to operate a compressor stably and easily under overload or low voltage conditions, and a method for controlling the same.

1 . A refrigerator having a compressor, the refrigerator comprising: 
 a motor driving the compressor;    a motor driver supplying power to the motor; and    a controller outputting a control signal corresponding to a second command speed to the motor driver, and outputting a control signal corresponding to a first command speed which is higher than the second command speed to the motor driver when a driving on/off ratio of the motor driver is maintained below a given reference driving on/off ratio for a given reference period.    
   
   
       2 . The refrigerator of  claim 1 , wherein the speed of the motor increases as the driving on/off ratio increases.  
   
   
       3 . The refrigerator of  claim 1 , wherein the controller outputs a control signal corresponding to a command speed lower than a given command speed to the motor driver when the speed of the motor does not reach the given command speed even though the driving on/off ratio is maximized.  
   
   
       4 . The refrigerator of  claim 1 , wherein when the speed of the motor reaches the first command speed, the controller increases the reference driving on/off ratio.  
   
   
       5 . The refrigerator of  claim 1 , wherein when the speed of the motor reaches the first command speed, the controller reduces the reference period.  
   
   
       6 . The refrigerator of  claim 1 , wherein when the speed of the motor does not reach the first command speed, the controller reduces the reference driving on/off ratio.  
   
   
       7 . The refrigerator of  claim 1 , wherein when the speed of the motor does not reach the first command speed, the controller increases the reference period.  
   
   
       8 . The refrigerator of  claim 1 , wherein the motor driver comprises an inverter having a switching element, and the driving on/off ratio can be replaced with a duty ratio of the switching element.  
   
   
       9 . A method for controlling a refrigerator having a motor and a motor driver driving the motor, the method comprising: 
 outputting a control signal corresponding to a second command speed to the motor driver;    determining whether a driving on/off ratio of the motor driver is maintained below a given reference driving on/off ratio for a given reference period; and    outputting a control signal corresponding to a first command speed which is higher than the second command speed when it is determined that the driving on/off ratio is maintained for the given reference period.    
   
   
       10 . The method of  claim 9 , further comprising increasing the reference driving on/off ratio when the speed of the motor reaches the first command speed.  
   
   
       11 . The method of  claim 9 , further comprising decreasing the reference period when the speed of the motor reaches the first command speed.  
   
   
       12 . The method of  claim 9 , further comprising reducing the reference driving on/off ratio when the speed of the motor does not reach the first command speed.  
   
   
       13 . The method of  claim 9 , further comprising increasing the reference period when the speed of the motor does not reach the first command speed.  
   
   
       14 . A method for controlling a refrigerator having a compressor, the compressor being driven by a motor and a motor driver driving the motor, the method comprising: 
 outputting a first command speed to the motor driver, the first command speed being higher than a normal speed of the motor; and    determining whether a driving on/off ratio of the motor driver is maximized and if the driving on/off ratio of the motor driver is not maximized outputting a second command speed which is lower than the first command speed.    
   
   
       15 . The method of  claim 14 , further comprising outputting the first command speed when it is determined that the driving on/off ratio is maintained for a reference period when driven at the second command speed.