Washing machine and control method thereof

Abstract

A washing machine capable of performing washing by increasing a water level when an overload of a motor is detected, and a control method thereof. The washing is performed by detecting an overload of the motor using a load detecting circuit and changing a water level to a highest water level when the overload is detected. Thus, a burning smell may not be caused from the motor by preventing stalling of the motor, and washing performance may be maintained since the motor is continuously operated without stopping.

What is claimed is: 
     
         1 . A method of controlling a washing machine comprising a washing tub to accommodate laundry, a pulsator rotatably installed in the washing tub, and a motor to rotate the pulsator, the method comprising:
 setting a level of water supplied to the washing tub;   rotating the motor clockwise and counterclockwise after supplying water to the washing tub up to the set water level;   detecting an overload of the motor while rotating the motor clockwise and counterclockwise; and   changing the set water level to a higher water level when the overload of the motor is detected and performing cycles of the washing machine.   
     
     
         2 . The method according to  claim 1 , wherein the setting of the water level is performed after detecting weight of the laundry. 
     
     
         3 . The method according to  claim 2 , wherein the setting of the water level is performed by setting the water level according to the detected weight of the laundry. 
     
     
         4 . The method according to  claim 2 , wherein the setting of the water level is performed by selecting the water level according to manipulation by a user. 
     
     
         5 . The method according to  claim 4 , wherein the detecting of the overload of the motor is performed after a water supplying cycle of initially supplying water to wash the laundry. 
     
     
         6 . The method according to  claim 1 , wherein the detecting of the overload of the motor is performed before performing the cycles of the washing machine. 
     
     
         7 . The method according to  claim 1 , wherein the rotating of the motor clockwise and counterclockwise comprises:
 rotating the motor in one direction for a first time period;   stopping the rotation of the motor for a second time period after rotating the motor in the one direction;   rotating the motor in the opposite direction for a third time period after the second time period; and   stopping the rotation of the motor for a fourth time period after rotating the motor in the opposite direction.   
     
     
         8 . The method according to  claim 7 , further comprising counting pulse signals generated by counter electromotive force of the motor while the motor is stopped. 
     
     
         9 . The method according to  claim 8 , further comprising:
 counting a time period taken to rotate the motor clockwise and counterclockwise; and   stopping the rotation of the motor clockwise and counterclockwise when the counted time period is greater than a predetermined time period.   
     
     
         10 . The method according to  claim 9 , wherein the detecting of the overload of the motor is performed by determining that the motor is overloaded when a sum of the counted pulse signals is less than a reference value. 
     
     
         11 . The method according to  claim 1 , wherein the changing of the set water level is performed by changing the set water level to a highest water level. 
     
     
         12 . The method according to  claim 7 , wherein the rotating of the motor in one direction is performed by rotating the motor in a regular direction for the first time period while maintaining a constant motor RPM. 
     
     
         13 . The method according to  claim 12 , wherein the rotating of the motor in the opposite direction is performed by rotating the motor in the reverse direction for the third time period while maintaining a constant motor RPM. 
     
     
         14 . The method according to  claim 13 , further comprising changing the motor RPM when the motor is rotated clockwise and counterclockwise. 
     
     
         15 . The method according to  claim 7 , further comprising motor driving time or motor stopping time while rotating the motor clockwise and counterclockwise. 
     
     
         16 . A method of controlling a washing machine comprising a washing tub to accommodate laundry, a pulsator rotatably installed in the washing tub, and a motor to rotate the pulsator and the washing tub, the method comprising:
 rotating the motor clockwise and counterclockwise after a water supplying cycle to supply water to a set water level for washing the laundry;   detecting an overload of the motor while rotating the motor clockwise and counterclockwise; and   changing the set water level to a highest water level when the overload of the motor is detected and performing cycles of the washing machine.   
     
     
         17 . A washing machine comprising:
 a washing tub to accommodate laundry;   a pulsator rotatably installed in the washing tub;   a motor to rotate the pulsator;   a load detector to detect a weight of the laundry; and   a controller to perform an overload detecting cycle by rotating the motor clockwise and counterclockwise after supplying water to the washing tub up to a set water level, and detecting an overload of the motor using the load detector while the motor is rotated clockwise and counterclockwise,   wherein the overload detecting cycle to detect an overload by performing an operation of rotating the motor clockwise and counterclockwise for a predetermined time period comprises
 rotating the motor in one direction for a first time period after supplying water to the washing tub; 
 stopping the rotation of the motor for a second time period after rotating the motor in the one direction; 
 rotating the motor in the opposite direction for a third time period after the second time period; and 
 stopping the rotation of the motor for a fourth time period after rotating the motor in the opposite direction. 
   
     
     
         18 . The washing machine according to  claim 17 , wherein the controller counts pulse signals generated by counter electromotive force of the motor while the motor is stopped during the rotation of the motor, compares a sum of the counted pulse signals with a reference value, and determines that the motor is overloaded when the counted pulse is less than the reference value. 
     
     
         19 . The washing machine according to  claim 18 , wherein the controller sets the water level according to the detected weight of the laundry. 
     
     
         20 . The washing machine according to  claim 19 , wherein the controller changes the set water level to a higher water level when the overload of the motor is detected. 
     
     
         21 . The washing machine according to  claim 18 , further comprising an input unit to select a level of water supplied to the washing tub, wherein the controller changes the selected water level to a higher water level when an overload of the motor is detected. 
     
     
         22 . The washing machine according to  claim 21 , wherein the controller changes the set water level to a highest water level.