Washing machine driving device, and washing machine and driving method using same

Abstract

Provided are an apparatus for and a driving method of driving a washing machine in which a washing tub is rotated by an inertial force in a freewheeling condition or at a low power driving mode, and a pulsator is reversely rotated, in a state where the pulsator and the washing tub are rotated in one direction. When driving the pulsator and the washing tub in the opposite directions, the inner rotor and the outer rotor are driven in a first direction where the washing tub is rotated, to then set the inner rotor to any one of a free-wheeling mode, an intermittent driving mode, and a low power driving mode, to thus rotate the washing tub, and the outer rotor is driven in one direction opposing the first direction to thus reversely rotate the pulsator.

1 . An apparatus for driving a washing machine, the washing machine driving apparatus comprising:
 a stator that is fixed to a lower surface of an outer tub and on an inner side and an outer side of which a first coil and a second coil are provided, respectively;   an inner rotor that is disposed with a gap on an inner circumferential surface of the first coil of the stator and connected with a washing tub;   an outer rotor that is disposed with a gap on an outer circumferential surface of the second coil of the stator and connected with a pulsator; and   a control unit that applies a first drive signal and a second drive signal independently to the first coil and the second coil,   wherein when the control unit drives the pulsator and the washing tub in the opposite directions, the control unit drives the inner rotor and the outer rotor in a first direction where the washing tub is rotated, to then set the inner rotor to any one of a free-wheeling mode, an intermittent driving mode, and a low power driving mode, to thus rotate the washing tub, and drives the outer rotor in one direction opposing the first direction to thus reversely rotate the pulsator.   
     
     
         2 . The driving apparatus of  claim 1 , wherein the control unit drives the inner rotor and the outer rotor simultaneously or sequentially drives the inner rotor and the outer rotor at time intervals when driving the inner rotor and the outer rotor in a first direction. 
     
     
         3 . The driving apparatus of  claim 1 , wherein the control unit drives the pulsator and the washing tub at different speeds when driving the pulsator and the washing tub in the opposite directions to each other. 
     
     
         4 . The driving apparatus of  claim 1 , wherein the control unit drives the pulsator and the washing tub at variable speeds, when driving the pulsator and the washing tub in the opposite directions to each other, to thus form a strong water stream in a pattern shape. 
     
     
         5 . The driving apparatus of  claim 1 , wherein the control unit comprises:
 a first driver for generating a first drive signal applied to a first coil in order to drive the inner rotor;   a second driver for generating a second drive signal applied to a second coil in order to drive the outer rotor; and   a controller for controlling the first driver and the second driver.   
     
     
         6 . The driving apparatus of  claim 1 , further comprising:
 an outer shaft whose one end is connected with the washing tub and whose other end is connected with the inner rotor; and   an inner shaft which is rotatably disposed within the outer shaft and whose one end is connected with the pulsator and whose other end is connected with the outer rotor.   
     
     
         7 . A method of driving a washing machine including an apparatus for driving the washing machine, in which the washing machine driving apparatus includes: a stator that is fixed to a lower surface of an outer tub and on an inner side and an outer side of which a first coil and a second coil are provided, respectively; an inner rotor that is disposed with a gap on an inner circumferential surface of the stator and connected with a washing tub; an outer rotor that is disposed with a gap on an outer circumferential surface of the stator and connected with a pulsator; and a control unit that applies a first drive signal and a second drive signal independently to the first coil and the second coil, to drive the inner rotor and the outer rotor, the method comprising:
 when driving the pulsator and the washing tub in the opposite directions to each other, driving the inner rotor and the outer rotor in a first direction where the washing tub is rotated;   rotating the washing tub by setting the inner rotor to any one of a free-wheeling mode, an intermittent driving mode, and a low power driving mode; and   driving the outer rotor in one direction opposing the first direction to thus reversely rotate the pulsator.   
     
     
         8 . The driving method of  claim 7 , wherein the step of driving the inner rotor and the outer rotor in the first direction comprises the step of driving the outer rotor and the inner rotor in the first direction simultaneously, by applying the first drive signal and the second drive signal to the first coil and the second coil, respectively. 
     
     
         9 . The driving method of  claim 7 , wherein the step of driving the inner rotor and the outer rotor in the first direction comprises the step of driving the outer rotor and then sequentially driving the inner rotor at a preset time interval. 
     
     
         10 . The driving method of  claim 9 , further comprising:
 after driving the outer rotor first in the first direction, executing a Proportional-Integral (PI) control or a Proportional Integral and Derivative (PID) control so that the rotational speed of the outer rotor reaches a preset round per minute (RPM);   determining whether the outer rotor has been started normally by executing the PI control or PID control;   starting the inner rotor and the outer rotor in an identical direction in a state in which the outer rotor is rotationally driven in the first direction; and   controlling the rotational speeds of the inner rotor and the outer rotor so as to reach predetermined RPMs by executing the PI control or PID control of the inner rotor and the outer rotor.   
     
     
         11 . The driving method of  claim 10 , wherein the step of determining whether the outer rotor has been normally started is executed by any one method of the following methods or a method of having a combination of at least two methods thereof: a first method of determining a drive has been made for a preset time; a second method of determining whether a RPM of the outer rotor has reached a preset value; a third method of determining whether an amount of current of the second drive signal applied to the second coil has reached a preset value. 
     
     
         12 . The driving method of  claim 7 , further comprising the step of determining whether the inner rotor has been normally started in the first direction before the step of setting the inner rotor in a freewheeling mode, an intermittent driving mode or a low-power drive mode, and rotating the washing tub. 
     
     
         13 . The driving method of  claim 12 , wherein the step of determining whether the inner rotor has been normally started is executed by any one method of the following methods or a method of having a combination of at least two methods thereof: a first method of determining a drive has been made for a preset time; a second method of determining whether a RPM of the inner rotor has reached a preset value; a third method of determining whether an amount of current of the first drive signal applied to the first coil has reached a preset value. 
     
     
         14 . The driving method of  claim 7 , wherein the step of rotating the washing tub by setting the inner rotor in the free-wheeling mode blocks the second drive signal applied to the second coil from the control unit. 
     
     
         15 . The driving method of  claim 7 , wherein when the pulsator and the washing tub are driven in opposite directions to each other, the pulsator and the washing tub are driven at different speeds, at an identical speed, or at variable speeds. 
     
     
         16 . The driving method of  claim 7 , further comprising the steps of:
 after reversely rotating the pulsator, driving the outer rotor and the inner rotor so that the washing tub is rotated in a second direction opposite to the first direction, to thus rotate the pulsator and the washing tub in the second direction step;   setting the inner rotor in a freewheeling mode, an intermittent driving mode or a low-power drive mode, thus rotating the washing tub; and   reversely rotating the pulsator in one direction opposite to the rotational direction of the washing tub by driving the outer rotor in the first direction.   
     
     
         17 . A washing machine comprising:
 a washing tub that is suspended and supported inside a case;   a washing tub rotatably disposed inside the outer tub to thus perform washing and dehydrating;   a pulsator rotatably disposed within the washing tub to thus form a wash water stream; and   a driving apparatus that is mounted in a lower portion of the outer tub and drives the washing tub and the pulsator at the same time or alternatively, wherein the driving apparatus comprises: a stator that is fixed to a lower surface of an outer tub and on an inner side and an outer side of which a first coil and a second coil are provided, respectively; an inner rotor that is disposed with a gap on an inner circumferential surface of the first coil of the stator and connected with a washing tub; an outer rotor that is disposed with a gap on an outer circumferential surface of the second coil of the stator and connected with a pulsator; and a control unit that applies a first drive signal and a second drive signal independently to the first coil and the second coil,   wherein when the control unit drives the pulsator and the washing tub in the opposite directions, the control unit drives the inner rotor and the outer rotor in a first direction where the washing tub is rotated, to then set the inner rotor to any one of a free-wheeling mode, an intermittent driving mode, and a low power driving mode, to thus rotate the washing tub, and drives the outer rotor in one direction opposing the first direction to thus reversely rotate the pulsator.