Unbalance detection method and washing machine using the same

Abstract

A washing machine and unbalance detection method using the same, which is capable of efficiently detecting unbalance of a rotation tub. A washing machine includes: a washing motor rotating a rotation tub accommodating laundry; a motor velocity detection unit detecting a velocity of the washing motor and outputting a motor velocity signal; and a controller determining whether unbalance of the rotation tub occurs according to an unbalance level determined on the basis of a velocity ripple of the motor velocity signal, and controlling the washing motor according to the determination result. A method of detecting unbalance of a rotation tub accommodating the laundry in a washing machine includes: driving a washing motor in order to rotate the rotation tub; detecting a velocity of the washing motor, and outputting a motor velocity signal; extracting a velocity ripple of the motor velocity signal, the velocity ripple being generated while detecting the velocity of the washing motor; operating the extracted velocity ripple, and detecting an unbalance level; and comparing the detected unbalance level with a reference value, and determining whether the unbalance of the rotation tub occurs.

1 . A washing machine comprising: 
 a washing motor rotating a rotation tub accommodating laundry;    a motor velocity detection unit detecting velocity of the washing motor and outputting a motor velocity signal; and    a controller determining whether an unbalance of the rotation tub occurs according to an unbalance level determined based on a velocity ripple of the motor velocity signal, and controlling the washing motor according to the determination result.    
   
   
       2 . The washing machine as set forth in  claim 1 , wherein the controller determines whether the unbalance of the rotation tub occurs in real time while driving the washing motor.  
   
   
       3 . The washing machine as set forth in  claim 1 , wherein the controller determines whether the unbalance of the rotation tub occurs when the velocity of the washing motor varies.  
   
   
       4 . The washing machine as set forth in  claim 1 , wherein the controller determines whether the unbalance of the rotation tub occurs when the velocity of the washing motor remains constant.  
   
   
       5 . The washing machine as set forth in  claim 1 , wherein the controller comprises a high pass filter detecting the velocity ripple.  
   
   
       6 . The washing machine as set forth in  claim 5 , wherein the high pass filter has a cutoff frequency which does not exceed ¼ of an angular speed of the rotation tub.  
   
   
       7 . The washing machine as set forth in  claim 1 , wherein the controller comprises: 
 a low pass filter filtering other components generated according to mechanical characteristics other than an unbalance component; and    an absolute value operation unit detecting an unbalance level according to the unbalance component.    
   
   
       8 . The washing machine as set forth in  claim 7 , wherein the controller further comprises an unbalance determination unit comparing the unbalance level filtered through the low pass filter with a reference level, and for determining whether the unbalance occurs.  
   
   
       9 . A method of detecting unbalance of a rotation tub accommodating the laundry in a washing machine, the method comprising; 
 driving a washing motor in order to rotate the rotation tub;    detecting a velocity of the washing motor, and outputting a motor velocity signal;    extracting a velocity ripple of the motor velocity signal, the velocity ripple being generated during detection of the velocity of the washing motor;    detecting an unbalance level on the basis of the extracted velocity ripple, and; and    comparing the detected unbalance level with a reference value, and determining whether the unbalance of the rotation tub occurs.    
   
   
       10 . The method as set forth in  claim 9 , wherein said extracting velocity ripple is performed using a high pass filter with a preset cutoff frequency.  
   
   
       11 . The method as set forth in  claim 9 , wherein the detecting an unbalance level includes performing operations on an absolute value of the velocity ripple, and filtering components other than an unbalance component of the absolute value operated signal using a low pass filter, wherein other components are generated by mechanical characteristics.  
   
   
       12 . The method as set forth in  claim 9 , wherein the rotation tub is rapidly rotated when the resulting determination state indicates a balance state, and an actual spin-dry operation is performed.  
   
   
       13 . The method as set forth in  claim 9 , wherein the detecting an unbalance level is simultaneously performed with a clinging operation for causing the laundry to cling to the inside of the rotation tub.  
   
   
       14 . A method of decreasing a duration of a spin-drying clothes drying operation, comprising: 
 detecting a first velocity of a tub rotating motor rotating a tub and outputting a motor velocity signal;    extracting a velocity ripple of the motor velocity signal, the velocity ripple being generated during detection of the velocity of the washing motor;    determining an absolute value of the extracted velocity ripple;    detecting a level of unbalance from the absolute value of the extracted velocity ripple;    comparing the detected unbalance level with a reference value and determining that an unbalance of the tub is not present when the detected unbalance level is less than or equal to the reference level;    rotating the tub at a second velocity higher than the first velocity when an unbalance of the tub is not present.    
   
   
       15 . The method as set forth in  claim 14 , further comprising rotating the tub at the first velocity when an unbalance of the tub is present, wherein the comparing further comprises determining that an unbalance of the tub is present when the detected unbalance level is greater than the reference level.