KR101407960B1 - Washing machine and control method thereof - Google Patents

Abstract

A washing machine and its control method capable of reducing high-frequency noises generated during rotation of a motor are disclosed. The washing machine includes a speed sensing part for sensing the speed of the motor and a control part for outputting a speed control signal for controlling the speed of the motor. The control part confirms whether the high speed or low speed constant speed section is entered during the dewatering process, When entering the constant speed section, the motor speed can be repeatedly raised and lowered within a certain range to reduce high frequency noises.

Description

[0001] WASHING MACHINE AND CONTROL METHOD THEREOF [0002]

And more particularly, to a washing machine and its control method capable of reducing high-frequency noises generated during rotation of a motor.

Generally, a washing machine includes a drum washing machine in which clothes are washed by an impact force between clothes and washing water dropped by the rotation of a drum, and a drum washing machine in which a pulsator is rotated on the bottom surface of the drum, And a forced water flow is generated by an edger protruding into the inside of the washing tub, and the washer washing machine is carried out by the washing machine by the friction force between the clothes and the washing water.

Under such a background, when the washing cycle of the various types of washing machines described above is performed, an operation is performed in which the drum, the pulsator or the oscillator rotates in the forward and reverse directions to rotate the washing water or stir the clothes. When the dewatering process is performed, the drum in which the clothes are entirely accommodated is rotated at a high speed so that centrifugal force is applied to the clothes, and water that is wet by the clothes is released by the centrifugal force.

On the other hand, the manner in which the motor of the washing machine is rotated is generally driven by a PWM (Pulse Width Modulation) control method. In the PWM control method, a triangular wave carrier signal and a sine wave reference signal are inputted to a comparator together, and a specific type of PWM signal is output. The PWM signal controls the switching of the inductor, and the motor drive signal output from the inductor is input to each coil of the motor to induce the rotational force of the motor. Such a PWM control method changes the rotation speed of the motor by changing the frequency of the triangular wave and the sinusoidal wave.

One aspect of the present invention provides a washing machine and a control method thereof capable of reducing high-frequency noise generated in a constant speed section during a dewatering cycle of a washing machine.

The method for controlling a washing machine according to an embodiment of the present invention includes detecting a speed of a universal motor during a dewatering process and checking whether the universal motor enters a constant speed section, It is preferable to repeatedly raise and lower the speed of the universal motor within a certain RPM so as to reduce high frequency noises.

It is preferable that the upward and downward repetition of the speed of the universal motor within a certain RPM is repeated by adjusting the command speed of the universal motor so that the actual speed of the universal motor is raised and lowered within a certain RPM.

It is preferable that the command speed of the universal motor is regulated by repeatedly raising and lowering the command speed of the universal motor within a certain RPM.

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It is preferable that the voltage applied to the universal motor is repeatedly raised and lowered within a predetermined voltage by repeating rising and falling of the voltage applied to the universal motor within a predetermined voltage by adjusting the duty of the voltage.

It is preferable that the voltage applied to the universal motor is repeatedly raised and lowered within a predetermined voltage by repeating rising and falling of the voltage applied to the universal motor within a predetermined voltage by adjusting the phase of the voltage.

It is preferable that the speed of the universal motor is repeatedly raised and lowered within a certain RPM by repeatedly raising and lowering the speed of the universal motor periodically within a predetermined RPM.

It is preferable that the speed of the universal motor is repeatedly raised and lowered within a certain RPM by repeating the raising and lowering of the speed of the universal motor non-periodically within a certain RPM.

The washing machine according to an embodiment of the present invention includes a universal motor and a control unit for repeating the rising and falling of the speed of the universal motor within a predetermined RPM so as to reduce high- frequency noise when entering a high- ; ≪ / RTI >

The controller may adjust the command speed of the universal motor so that the speed of the universal motor is repeatedly increased and decreased within a predetermined RPM.

The controller may adjust the voltage applied to the universal motor so that the speed of the universal motor is repeatedly increased and decreased within a predetermined RPM.

Preferably, the control unit repeatedly raises and lowers the voltage applied to the universal motor within a predetermined voltage, and repeatedly raises and lowers the speed of the universal motor within a predetermined RPM.

The controller may adjust the duty of the voltage so that the voltage applied to the universal motor is repeatedly raised and lowered within a predetermined voltage.

It is preferable that the voltage applied to the universal motor is repeatedly raised and lowered within a predetermined voltage by repeating rising and falling of the voltage applied to the universal motor within a predetermined voltage by adjusting the phase of the voltage.

Preferably, the controller repeatedly raises and lowers the speed of the universal motor within a predetermined RPM.

Preferably, the controller repeatedly raises and lowers the speed of the universal motor non-periodically within a certain RPM.

According to an aspect of the present invention, when the motor enters a high-speed or low-speed constant speed section during the dewatering stroke, the speed of the universal motor is repeatedly increased and decreased within a certain RPM, thereby reducing high- frequency noise.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a view schematically showing the overall configuration of a washing machine according to an embodiment of the present invention.

1, the washing machine 10 includes a housing 20 forming an outer appearance, a control panel 30 provided at an upper front of the housing 20, a drum 40 provided inside the housing 20, A tub 50 surrounding the drum 40, and a universal motor 29 driven to rotate the drum 40 to perform a washing, rinsing and dewatering steps.

The housing 20 forms an appearance of the washing machine 10. [ In the interior of the housing 20, various types of apparatuses necessary for operating the washing machine 10 are provided. A door 25 is provided at the front opening 22 of the housing 20 to be openable and closable by a hinge structure. A transparent observation window 27 is provided at the center of the door 25 so that the degree of progress of the washing can be observed from the outside without opening the door 25. [

The control panel 30 includes various operation buttons 32 required by the user to operate the washing machine 10 and a display window 34 indicating the washing progress. The control panel 30 is coupled to the upper portion of the front surface of the housing 20 through a hook or a screw connection with the housing 20. A controller (not shown) is provided at the rear end of the control panel 30 to determine the amount of water supplied, adjust the amount of washing water, progress the washing process, determine the amount of rinsing water, progress the rinsing process, And the like.

The drum 40 is provided inside the housing 20 in a cylindrical shape, and is a space in which the laundry is accommodated and the washing process proceeds substantially. The drum 40 is made of stainless steel or the like which does not cause rust since it is a portion where the washing water is directly contacted. The drum 40 receives the rotational force transmitted from the universal motor 29, rotates clockwise or counterclockwise, and carries out a washing process on the laundry.

The tub 50 is provided to enclose the drum 40 and is a space for washing water. The tub 50 is provided at its upper end with an inflow channel 52 through which wash water flows. A detergent dispenser 53 is formed on the inflow passage 52 connected from the outside of the housing 20. The detergent is dissolved while the washing water enters the detergent input box 53 and the washing water containing the detergent dissolved therein flows into the tub 50 through the inflow channel 52. At the lower end of the tub 50, a discharge passage 54 through which wash water is discharged is provided. And the contaminated washing water is discharged to the outside of the washing machine 10 along the discharge flow path 54 in accordance with the control signal of the controller. When the drum 50 is eccentric due to laundry or washing water, the tub 50 connected to the drum 50 is vibrated. The housing 20 and the tub 50 are connected to a supporting device 56 to attenuate the vibration of the tub 50. A door packing 58 made of a stretchable material is formed between the housing 20 around the opening 22 where the tub 50 and the door 25 are provided. The vibration of the tub 50 is not directly transmitted to the housing 20 because the door packing 58 is made of a stretchable material.

The universal motor 29 rotates the drum 40 to perform a washing cycle, a rinsing cycle and a dewatering cycle. When the commercial AC power outputted from the power supply unit 60 is transmitted by duty control or phase control, the universal motor 29 rotates the drum 40 containing the laundry at a predetermined speed.

FIG. 2A is a schematic view of a universal motor according to an embodiment of the present invention, FIG. 2B is a perspective view illustrating a rotor structure of a universal motor according to an embodiment of the present invention, FIG. 1 is a front view showing a rotor structure of a universal motor.

2A to 2C, the universal motor 29 has a stator 2 fixed to the inside of a motor housing (not shown), and a rotor 200 is fixed to the inside of the stator 2, (5) is elastically contacted to the outer surface of the commutator (5) to supply electric power to the commutator (5). The commutator (5) A brush 7 is provided. The rotor 200 includes an armature core 110 formed at an outer peripheral surface of a base portion 111 into which a rotating shaft 4 is inserted and having a plurality of teeth 113 around which coils are wound, And a slot edge 130 provided between the teeth 113 and the teeth 113 to maintain insulation between the teeth 113 and the coils.

When the AC power is applied to the coil of the stator 2, the electric power flowing through the coil of the stator 2 is supplied to the commutator 5 through the brush 7, 5 rectify the alternating current to direct current in the commutator 5 and supply it to the coil of the rotor 200. The electricity flowing in the coil of the rotor 200 is supplied to the stator brush 7 and the stator 2) flows into the coil and escapes to the outside, and the rotor 200 rotates due to the magnetic field generated when electricity flows like this.

At this time, when the universal motor 29 rotates at a high speed due to the structure of the universal motor 29, high frequency noises due to mechanical friction between the brush 7 and the commutator 5 are generated. When the rotor 200 of the universal motor 29 is rotated, air flows into the stepped portion 9 formed between each tooth 113 and the slotted edge 130 as shown in FIG. 2C, A phenomenon occurs in which the portion 9 collides with the upper surface of the base member 9, which further increases the intensity of the high frequency noise and causes unpleasantness to the user.

3 is a schematic circuit diagram of a washing machine driving unit according to an embodiment of the present invention.

3, the washing machine driving unit includes a driving operation unit 80 by which a user can operate the washing machine 10, a speed sensing unit 90 that senses the speed of the motor 29, A triac 72 which is turned on / off by a speed control signal of the control unit 100; and a control unit 70 which controls the motor 29 to rotate forward or backward 1 and 2 relays 74 and 76, a power supply unit 60 for supplying power, a rectification unit 78 for rectifying and outputting commercial AC power, and a motor 29 for rotating the drum 40.

The driving operation unit 80 selects and inputs a desired washing course (for example, a washing cycle and a rinsing cycle) and outputs an electric signal corresponding thereto.

The speed sensing unit 90 senses the speed of the universal motor 29, and outputs a speed sensing signal corresponding to the sensed speed to the control unit 100, for example, a hall sensor.

The control unit 100 outputs a speed control signal for controlling the speed of the universal motor 29 (or the speed of the drum) and a switching control signal for forward and reverse rotation of the universal motor 29. The control unit 100 receives a key signal transmitted from the operation control unit 80 and outputs a speed control signal for controlling the speed of the universal motor 29 to the triac 72, And outputs a switching control signal for rotating or reversing the rotation to the first relay 74 and the second relay 76, respectively.

The control unit 100 changes the command speed of the universal motor 29 in the high speed or low speed constant speed section in the course of the dewatering process so as to reduce the high frequency noise by repeating the rise and fall of the speed of the universal motor 29 within a certain size range do.

The controller 100 changes the voltage applied to the universal motor 29 in the high speed or low speed constant speed section in the course of the dewatering process so that the speed of the universal motor 29 is repeatedly raised and lowered within a predetermined range to generate high frequency noises Reduce.

The control unit 100 adjusts the duty of the commercial AC power applied from the power supply unit 60 so that the voltage applied to the universal motor 29 is repeatedly raised and lowered within a predetermined magnitude range.

The control unit 100 controls the phase of the commercial AC power applied from the power supply unit 60 to a pulse width modulation (PWM) signal as a speed control signal to increase or decrease the voltage applied to the universal motor 29 within a predetermined size range Lt; / RTI > The controller 100 adjusts the input voltage applied to the universal motor 29 through phase control to vary its rotational force.

The triac 72 performs an on or off operation based on the speed control signal transmitted from the control unit 100. When the commercial ac power of the power supply unit 60 is turned on or off according to the on or off operation of the triac 72, ). The triac 72 varies the rotational speed of the universal motor 29 by changing the magnitude of the desired output voltage by controlling the applied commercial AC power to a point angle corresponding to a pulse width modulation (PWM) signal as a speed control signal. That is, the triac 72 controls the phase or duty of the commercial AC power and supplies it to the universal motor 29.

The first relay 74 and the second relay 76 are switched by the switching control signal of the controller 100 to rotate the universal motor 29 forward or reverse. For example, when the first relay 74 is switched to the A terminal by the switching control signal and the second relay 76 is switched to the D terminal, the A terminal of the first relay 74 and the second relay 74 The universal motor 29 is rotated in the forward direction as the voltage is supplied to the rotor 29a and the stator 29b of the universal motor 29 through the D terminal of the universal motor 29 and the universal motor 29 is driven in the normal rotation The drum 40 can be rotated forward and the dewatering process can proceed. On the other hand, when the first relay 74 is switched to the terminal B by the switching control signal and the second relay 76 is switched to the terminal C, the universal motor 29 rotates in the reverse direction.

The power supply unit 60 supplies the commercial AC power required for driving the washing machine, and the rectifying unit 78 rectifies and outputs the commercial AC power supplied from the power supply unit 60.

The universal motor 29 receives and drives a predetermined voltage output from the rectifying unit 78 and includes a rotor 29a and a stator 29b.

4A and 4B are graphs of speed control of a washing machine motor according to an embodiment of the present invention.

4A, the rotation speed of the universal motor according to the dewatering cycle of the washing machine is divided into a first acceleration period that constantly accelerates to the first speed V1, a low speed constant speed interval that maintains the first speed V1 for a predetermined time, A second acceleration section that constantly accelerates to the second speed V2, and a fast fixed section that maintains the second speed V2 for a predetermined time. The universal motor 29 generates high-frequency noise due to mechanical friction between the brush and the commutator during rotation. The noise caused by the mechanical friction of the universal motor 29 is generated in a high speed or low speed constant speed section where the constant speed is maintained. Therefore, when the speed of the universal motor 29 is changed in the high speed or low speed constant speed section and controlled to be the high speed or the low speed and the speed change state, the high frequency noise can be reduced.

The control unit 100 repeatedly raises and lowers the command speed of the universal motor 29 within a predetermined size range (for example, 20 RPM) in order to reduce the high frequency noise. When the command speed of the universal motor 29 is repeatedly raised and lowered within a predetermined size range, the actual speed of the universal motor 29 is repeatedly raised and lowered within a predetermined range. As shown in FIG. 4A, when the command speed is periodically raised and lowered within a constant size range (for example, 20RPM) in the high speed or low speed constant speed section, the actual speed of the universal motor 29 Is repeatedly rising and falling within a certain size range.

4B shows an example in which when the command speed of the universal motor 29 is repeatedly raised and lowered non-periodically within a predetermined size range (for example, 20 RPM), the actual speed of the universal motor 29 is non- And repeating the rise and fall.

5A and 5B are graphs of speed control of a washing machine motor according to an embodiment of the present invention.

5A is a graph showing that the actual speed of the universal motor 29 repeats rising and falling with a certain period within a certain size range according to the magnitude of the voltage applied to the universal motor 29. The control unit 100 maintains the command speed of the universal motor 29 at a constant speed (for example, 1000 rpm) and controls the voltage applied to the universal motor 29 within a predetermined size range (for example, 2 V) To repeat the rising and falling. When the voltage applied to the universal motor 29 is repeatedly raised and lowered periodically within a predetermined size range, the actual speed of the universal motor 29 periodically rises and falls within a predetermined range (for example, 20 RPM) I repeat. The controller 100 may adjust the voltage applied to the universal motor 29 by controlling the phase of the commercial AC power using a pulse width modulation (PWM) signal, which is a speed control signal. The controller 100 controls the duty of the commercial AC power to adjust the voltage applied to the universal motor 29.

FIG. 5B is a graph showing that the actual speed of the universal motor 29 is repeatedly increased and decreased in a non-periodic manner within a predetermined size range according to the magnitude of the voltage applied to the universal motor 29. The control unit 100 maintains the command speed of the universal motor 29 at a constant speed (for example, 1000 rpm) and controls the voltage applied to the universal motor 29 within a predetermined size range (for example, 2 V) Repeatedly rising and falling periodically. If the voltage applied to the universal motor 29 repeatedly rises and falls non-periodically within a certain size range, the actual speed of the universal motor 29 rises non-periodically (for example, 20 RPM) And descent.

6A and 6B are graphs showing a noise waveform according to an operation frequency of a washing machine according to an embodiment of the present invention.

FIG. 6A shows the noise waveform of the operating frequency 2 kHz to 4 kHz band when the universal motor 29 rotates at 970 RPM, and it is found that the peak noise waveform occurs and the maximum noise intensity is 56 dB.

6B shows a noise waveform of 2 kHz to 4 kHz band when the universal motor 29 is rotated at 970 RPM using a noise canceling algorithm according to one aspect of the present invention (for example, phase control, duty control, command speed control) Respectively. Compared with FIG. 5A, it can be seen that the noise waveform is generally gentle, and the maximum noise intensity is reduced to 50 dB, which is 6 dB.

7 is a control flowchart of a washing machine according to an embodiment of the present invention.

As shown in Fig. 7, the controller 100 confirms whether the universal motor 29 enters a high-speed or low-speed constant speed section where the universal motor 29 rotates at high speed or low speed for a predetermined time or more. The dewatering cycle includes a first acceleration section that constantly accelerates to the first speed V1, a low speed section that maintains the first speed V1 for a predetermined time, a second acceleration section that constantly accelerates to the second speed V2, , And a high-speed constant interval maintaining the second speed (V2, V1 < V2) for a predetermined period of time (S10, S20)

Next, when it is determined that the high-speed or low-speed constant speed section has been entered, the controller 100 adjusts the command speed of the universal motor 29 so that the speed of the universal motor 29 is repeatedly raised and lowered within a predetermined range . The control unit 100 repeatedly raises and lowers the command speed of the universal motor 29 within a predetermined size range (for example, 20 RPM) in order to reduce the high frequency noise. When the command speed of the universal motor 29 is repeatedly raised and lowered within a predetermined magnitude range, the actual speed of the universal motor 29 is repeatedly raised and lowered within a predetermined magnitude range.

Next, the control unit 100 confirms whether the dewatering process is completed by elapsing the dewatering time or the like, and changes the command speed of the universal motor 29 to the command speed according to the next step. (s40, s50)

8 is a control flowchart of a washing machine according to an embodiment of the present invention.

8, the controller 100 confirms whether the universal motor 29 enters a high-speed or low-speed constant speed section where the universal motor 29 rotates at a high speed or a low speed for a predetermined time or longer (s100, s110)

Next, when it is determined that the high-speed or low-speed constant speed section has been entered, the controller 100 adjusts the voltage applied to the universal motor 29 so that the speed of the universal motor 29 is repeatedly increased and decreased within a predetermined range . The control unit 100 repeatedly raises and lowers the voltage applied to the universal motor 29 within a predetermined size range (for example, 2 V) in order to reduce high frequency noises. When the voltage applied to the universal motor 29 is repeatedly raised and lowered within a predetermined size range (for example, 2 V), the actual speed of the universal motor 29 is increased within a certain range (for example, 20 RPM) And descent. The control unit 100 adjusts the voltage applied to the universal motor 29 by controlling the phase of the commercial AC power with a pulse width modulation (PWM) signal as a speed control signal. The controller 100 controls the duty of the commercial AC power source to adjust the voltage applied to the universal motor 29. (s120)

Next, the control unit 100 checks whether the dewatering stroke is completed by elapsing the dewatering stroke time or the like, and changes the voltage applied to the universal motor 29 to a voltage corresponding to the stroke of the next step when it is confirmed that the dewatering stroke is completed (s130, s140)

1 is a view schematically showing the overall configuration of a washing machine according to an embodiment of the present invention;

2A is a schematic view showing a universal motor according to an embodiment of the present invention.

2B is a perspective view illustrating a rotor structure of a universal motor according to an embodiment of the present invention.

2C is a front view showing the rotor structure of the universal motor according to the embodiment of the present invention.

3 is a schematic circuit diagram of a washing machine driving unit according to an embodiment of the present invention.

4A and 4B are graphs showing the speed control graphs of the washing machine motor according to the embodiment of the present invention.

5A and 5B are graphs showing the speed control graphs of the washing machine motor according to the embodiment of the present invention.

6A and 6B are graphs showing a noise waveform according to an operation frequency of a washing machine according to an embodiment of the present invention

FIG. 7 is a flowchart of the control of the washing machine according to the embodiment of the present invention.

FIG. 8 is a flowchart showing the control of the washing machine according to the embodiment of the present invention.

Description of the Related Art [0002]

29: motor 60:

72: triac 78: rectifying part

100:

Claims (17)

During the dehydration run, the speed of the universal motor is sensed to check whether it enters the constant speed section, And repeating the rising and falling of the voltage applied to the universal motor within a constant voltage to repeatedly increase and decrease the speed of the universal motor within a predetermined RPM to reduce the high frequency noise. The method according to claim 1, Repeatedly raising and lowering the speed of the universal motor within a certain RPM, Wherein an instruction speed of the universal motor is adjusted so that the actual speed of the universal motor is repeatedly increased and decreased within a certain RPM. 3. The method of claim 2, Adjusting the command speed of the universal motor Wherein the command speed of the universal motor is repeatedly raised and lowered within a predetermined RPM. delete delete The method according to claim 1, To repeatedly raise and lower the voltage applied to the universal motor within a predetermined voltage, Wherein the duty of the voltage is adjusted so that the voltage applied to the universal motor is repeatedly raised and lowered within a predetermined voltage. The method according to claim 1, To repeatedly raise and lower the voltage applied to the universal motor within a predetermined voltage, And adjusting the phase of the voltage so that the voltage applied to the universal motor is repeatedly raised and lowered within a predetermined voltage. The method according to claim 1, Repeatedly raising and lowering the speed of the universal motor within a certain RPM, Wherein the speed of the universal motor is periodically repeatedly raised and lowered within a certain RPM. The method according to claim 1, Repeatedly raising and lowering the speed of the universal motor within a certain RPM, Wherein the speed of the universal motor is repeatedly increased and decreased in an irregular manner within a certain RPM. Universal motor; And controlling the speed of the universal motor to increase and decrease within a predetermined RPM so as to reduce high-frequency noise when the engine enters a constant speed region during the dewatering process. 11. The method of claim 10, Wherein the control unit adjusts the command speed of the universal motor so that the speed of the universal motor is repeatedly increased and decreased within a certain RPM. 11. The method of claim 10, Wherein the control unit adjusts the voltage applied to the universal motor so that the speed of the universal motor is repeatedly increased and decreased within a predetermined RPM. 13. The method of claim 12, Wherein the control unit repeatedly raises and lowers the voltage applied to the universal motor within a predetermined voltage to repeat the rising and falling of the speed of the universal motor within a predetermined RPM. 13. The method of claim 12, Wherein the control unit adjusts the duty of the voltage to repeat the rising and falling of the voltage applied to the universal motor within a predetermined voltage. 13. The method of claim 12, To repeatedly raise and lower the voltage applied to the universal motor within a predetermined voltage, And adjusting the phase of the voltage to repeat the rising and falling of the voltage applied to the universal motor within a predetermined voltage. 11. The method of claim 10, Wherein the controller repeatedly raises and lowers the speed of the universal motor within a predetermined RPM periodically. 11. The method of claim 10, Wherein the controller repeatedly raises and lowers the speed of the universal motor non-periodically within a certain RPM.

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