Washing machine

Abstract

A washing machine is disclosed. The washing machine includes a washing tub, a motor to rotate the washing tub, and a driving unit that drives the motor using a pulse width modulation (PWM) scheme, mixes a three-phase PWM scheme and a two-phase PWM scheme in a common operation mode, and drives the motor using the mixed PWM scheme. Therefore, the washing machine can reduce increase of temperature of an inverter controlling the motor during the operation time of the washing machine.

1 . A washing machine comprising:
 a washing tub;   a motor to rotate the washing tub; and   a driving unit to drive the motor using a pulse width modulation (PWM) scheme, to mix a three-phase PWM scheme and a two-phase PWM scheme in a common operation mode, and to drive the motor using the mixed PWM scheme.   
     
     
         2 . The washing machine according to  claim 1 , wherein the driving unit feeds back an output current flowing in the motor, and drives the motor on the basis of the output current. 
     
     
         3 . The washing machine according to  claim 1 , wherein the driving unit operates the motor in response to the three-phase PWM scheme in a laundry-amount sensing section or an eccentricity sensing section. 
     
     
         4 . The washing machine according to  claim 3 , wherein:
 in either the laundry-amount sensing section or the eccentricity sensing section from among a dehydration cycle, the motor is driven according to the three-phase PWM scheme; and   in the remaining sensing sections other than either the laundry-amount sensing section or the eccentricity sensing section from among the dehydration cycle, the motor is driven according to the two-phase PWM scheme.   
     
     
         5 . The washing machine according to  claim 1 , wherein the driver drives the motor using the three-phase PWM scheme in a dehydration cycle, and drives the motor using the two-phase PWM scheme in at least one of a washing cycle and a rinsing cycle. 
     
     
         6 . The washing machine according to  claim 3 , wherein the driving unit drives the motor using the three-phase PWM scheme in the laundry-amount sensing section or the eccentricity sensing section from among a dehydration cycle, and drives the motor using the two-phase PWM scheme either in the remaining sensing sections other than the laundry-amount sensing section or the eccentricity sensing section from among the dehydration cycle or in at least one of a washing cycle and a rinsing cycle. 
     
     
         7 . The washing machine according to  claim 1 , wherein the driving unit divides its operation section into a section for the three-phase PWM scheme and a section for the two-phase PWM scheme in response to temperature, so as to be driven in different ways according to the three-phase PWM section and the two-phase PWM section in response to the temperature. 
     
     
         8 . The washing machine according to  claim 1 , wherein the driving unit divides an operation section thereof into a section for the three-phase PWM scheme and a section for the two-phase PWM scheme in response to a rotation speed of the motor, so as to be driven in different ways according to the three-phase PWM section and the two-phase PWM section in response to the rotation speed of the motor. 
     
     
         9 . The washing machine according to  claim 1 , wherein the driving unit includes:
 an inverter to convert predetermined DC power into AC power having a predetermined frequency, and to output the AC power to the motor;   an output current detection unit to detect output current flowing in the motor; and   an inverter controller to control the inverter in response to the output current in such a manner that the motor is driven according to the three-phase PWM scheme or the two-phase PWM scheme.   
     
     
         10 . The washing machine according to  claim 9 , wherein:
 the driving unit further includes a position detection unit to detect a rotor position of the motor, and   the inverter controller controls the inverter on the basis of the detected rotor position and the output current.   
     
     
         11 . The washing machine according to  claim 9 , wherein the inverter includes three pairs of switching elements, each pair including an upper-arm switching element and a lower-arm switching element,
 by the two-phase PWM scheme, during at least some sections from among a period in which upper-arm or lower-arm switching elements of two pairs from among the three pairs of switching elements are repeatedly turned on and off, the remaining one pair of upper-arm or lower-arm switching elements from among the three pairs of upper-arm or lower-arm switching elements is turned on or off.   
     
     
         12 . The washing machine according to  claim 1 , wherein:
 a sinusoidal wave flows in three phases of the motor according to the two-phase PWM scheme.   
     
     
         13 . A washing machine comprising:
 a washing tub;   a motor to rotating the washing tub; and   an inverter including three pairs of switching elements, each pair having an upper-arm switching element and a lower-arm switching element, in at least some sections from among a period in which upper-arm or lower-arm switching elements of two pairs from among the three pairs of switching elements are repeatedly turned on and off, for mixing a first section in which one switching element of the remaining one pair of from among the three pairs of switching elements is continuously turned on and the other switching element is continuously turned off and a second section in which the upper-arm and lower-arm switching elements of three pairs of switching elements are repeatedly turned on and off, and driving the motor according to the mixed result.   
     
     
         14 . The washing machine according to  claim 13 , further comprising:
 an inverter controller to output a switching control signal based on a two-phase PWM scheme to the inverter during the first section, and output a switching control signal based on a three-phase PWM scheme to the inverter during the second section.   
     
     
         15 . The washing machine according to  claim 13 , wherein the some sections may be a period corresponding to an electric angle of 120° of the motor.