CN112805432A

CN112805432A - Washing machine

Info

Publication number: CN112805432A
Application number: CN201980065291.3A
Authority: CN
Inventors: 金川朋之; 三宅博之; 加加见真
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2018-10-02
Filing date: 2019-10-01
Publication date: 2021-05-14
Anticipated expiration: 2039-10-01
Also published as: EP3824129A4; KR20200038406A; JP2020054628A; EP3824129B1; EP3824129A1; CN112805432B

Abstract

In any type of washing machine, the amount of laundry introduced into the washing machine can be measured with high accuracy in a short time. The washing machine includes: a rotating spin tub into which laundry is introduced; a driving unit including a motor for rotating the spin basket; and at least one processor configured to control the driving unit to rotate the spin basket at a first rotation speed, control the driving unit to rotate the spin basket at a second rotation speed, and identify the weight of the laundry based on an acceleration when the rotation speed of the spin basket is changed from the first rotation speed to the second rotation speed and the second rotation speed.

Description

Washing machine

Technical Field

The present disclosure relates to a washing machine, and more particularly, to a washing machine having a technique of measuring the weight of laundry introduced into the washing machine.

Background

Most of the washing machines of today have automatic washing, rinsing, spin-drying and other processes. In each of the washing and rinsing processes, water supply is automatically performed, and in this case, the amount of laundry (clothes) introduced into the washing machine is automatically measured to determine the amount of water to be supplied.

For example, referring to patent document 1, after a washing tub is loaded with clothes, the washing tub is rotated by motor driving. As the rotation of the washing tub is accelerated, an acceleration time until the rotation speed of the washing tub reaches a certain rotation speed is measured.

Subsequently, the rotation of the washing tub is decelerated, and a deceleration time until the rotation of the washing tub reaches a certain rotation speed is measured. The acceleration and deceleration of the rotation are calculated, and finally, the moment of inertia of the washing tub containing the clothes is calculated. The amount of clothing is determined from the correlation between the moment of inertia and the weight of the clothing.

Referring to patent document 2, after laundry is introduced into a drum, the drum is rotated by motor driving, and then conduction of the motor is terminated. Then, the drum is rotated by inertia, gradually decelerated due to a frictional torque of the motor, and finally stopped. Since the time required to stop the drum is proportional to the weight of the clothes, the proportional relationship is used to measure the amount of the clothes.

Documents of the prior art

Patent document 1: japanese patent laid-open No. 2003-210888

Patent document 2: japanese patent laid-open publication No. 2013-43030

Disclosure of Invention

Technical problem

In patent documents 1 and 2, a change in a rotation state when decelerating a spin tub (or a washing tub, a drum) containing clothes is used to measure the weight of the laundry.

In order to use the change of the rotation state during deceleration, it is necessary to rotate the spin basket to a sufficiently high number of rotations per minute (rpm). Therefore, it takes some time to measure the weight of the laundry. In order to improve the measurement accuracy of the laundry weight, the measurement needs to be performed several times, but in this case, it takes more time.

Further, in the methods disclosed in patent documents 1 and 2, the rotation of the motor and the spin basket needs to be made uniform. In other words, a so-called "direct drive" is premised, which means that the rotating shaft of the motor directly rotates the spin basket. In the indirect driving method in which the motor drives the spin basket by the belt, there is a rotation difference between the motor and the spin basket, thereby making it difficult to obtain sufficient measurement accuracy.

Further, among the washing machines equipped with a clutch between the spin basket and the motor, there is a type of washing machine having a spin basket automatically separated from the motor during deceleration of the spin basket. With this type of washing machine, it is impossible to use the methods disclosed in patent documents 1 and 2.

Technical scheme

The present disclosure provides a washing machine having a technique of accurately measuring the weight of laundry introduced into the washing machine in a short time.

According to an aspect of the present disclosure, a washing machine includes: a rotating spin basket into which laundry is introduced; a driving unit including a motor to rotate the spin basket; and at least one processor configured to control the driving unit to rotate the spin basket at a first rotation speed, control the driving unit to rotate the spin basket at a second rotation speed, and identify the weight of the laundry based on an acceleration when the rotation speed of the spin basket is changed from the first rotation speed to the second rotation speed and the second rotation speed.

The washing machine rotates the spin basket by torque control, which applies a certain torque to the spin basket containing the laundry. The spinning tub, which is engaged with the motor output, is then accelerated and then rotated at a constant rotational speed corresponding to the torque. The at least one processor may control the drive unit to rotate the spin basket at a first rotational speed by applying a first torque and then to rotate the spin basket at a second rotational speed by applying a second torque greater than the first torque.

The washing machine can measure acceleration and rotation speed of the spin tub in a stable state, and can more accurately measure the weight of laundry.

Since the acceleration and rotation speed of the spin basket are affected by mechanical loss, it is impossible to obtain a highly accurate measurement of the weight of the laundry when the measurement is performed based on the acceleration and rotation speed on which the mechanical loss is not reflected. In this regard, the acceleration and the rotational speed affected by the mechanical loss have a predefined linear relationship associated with the magnitude of the load applied to the spin basket.

The washing machine may measure the weight of the laundry by using the linear relationship and based on the acceleration and the rotation speed during the spin tub constant speed rotation. Accordingly, the washing machine can measure the weight of laundry with high accuracy without using the change of the rotation state during deceleration. Accordingly, various types of washing machines can measure the weight of laundry with high accuracy in a short time, thereby ensuring high versatility and more effective water saving.

The washing machine may further include at least one memory, and the at least one memory may store basic information including linear relationship information between acceleration and a second rotation speed associated with a magnitude of a load applied to the spin tub, and the at least one processor may identify the weight of the laundry based on the acceleration, the second rotation speed, and the basic information.

Linear relation information required for measuring the weight of laundry is stored in advance as data, and the weight of laundry can be measured quickly and clearly with high accuracy.

When the motor is an asynchronous motor, the at least one processor may control the drive unit to drive the motor at a first voltage and a first frequency such that the spin tub rotates at a first rotational speed, and control the drive unit to drive the motor at a second voltage and a second frequency such that the spin tub rotates at a second rotational speed.

Thus, the present disclosure can be easily applied to an existing washing machine.

In this case, the driving unit may further include an inverter for controlling driving of the motor, and the at least one processor may obtain the acceleration and the second rotation speed based on a current output from the inverter to the motor.

Thus, acceleration and rotation speed can be obtained without an additional device for measuring rotation speed or the like, thereby saving costs.

When the motor is a synchronous motor, the at least one processor may control the drive unit to drive the motor at a first current to rotate the spin tub at a first rotational speed, and control the drive unit to drive the motor at a second current to rotate the spin tub at a second rotational speed.

The washing machine may further include at least one memory, and the memory may store temperature correction information including linear relationship information between each of the acceleration and the second rotation speed and the temperature of the motor, and the at least one processor may correct the acceleration and the second rotation speed based on the temperature correction information.

Since the acceleration and the rotation speed are affected by the temperature of the motor, the accuracy of measuring the weight of the laundry may be reduced. In consideration of this, the washing machine according to the embodiment of the present disclosure corrects acceleration and rotation speed based on temperature correction information corresponding to the motor temperature when measuring the weight of laundry. Thus, the influence of the motor temperature can be reduced, and the weight of the laundry can be measured with high accuracy.

In this case, the at least one processor may identify the temperature of the motor based on the resistance of the coils of the motor and resistance information stored in the memory.

The at least one processor may control the drive unit to apply a predefined Direct Current (DC) voltage to the coil and measure a resistance of the coil.

Therefore, an additional temperature sensor is not required, and the temperature of the motor can be obtained, thereby saving the cost.

Further, the at least one processor may measure the weight of the laundry a plurality of times and identify the weight of the laundry based on the plurality of measurements. In this case, the at least one processor may control the drive unit to drive the spin basket to rotate at a different rotational speed each time.

Thus, the amount of laundry can be measured with higher accuracy, and water can be saved more efficiently.

Further, the driving unit may further include a clutch for switching between a connected state in which the motor and the spin basket are connected and a disconnected state in which the motor and the spin basket are disconnected, and the clutch may switch the spin basket from the connected state to the disconnected state when the spin basket is decelerated.

For the washing machine including the clutch, the existing method for measuring the weight of the laundry cannot be applied due to its structure. With the technology as described above, the washing machine including the clutch can measure the weight of laundry with high accuracy in a short time.

Further, the driving unit may further include a variable belt interposed between the motor and the spin basket for transmitting a driving force of the motor to the spin basket.

For the washing machine including the variable belt, the existing method for measuring the weight of the laundry may be applied, but the measurement accuracy may be lowered due to the structure. However, using the technology as described above, the washing machine including the variable belt can measure the weight of laundry with high accuracy in a short time.

Before proceeding with the following specific examples, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprise," as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or; the phrases "associated with," and derivatives thereof, may mean including, included within, interconnected with, contained within, connected to, or connected to, coupled to, or coupled with, communicable with, cooperative with, interleaved, juxtaposed, adjacent, bound to, or bound with, having a property of, etc.; and the term "controller" refers to any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

Also, the various functions described below may be implemented or supported by one or more computer programs, each formed from computer-readable program code, embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in suitable computer readable program code. The phrase "computer readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer readable medium" includes any type of medium capable of being accessed by a computer, such as Read Only Memory (ROM), Random Access Memory (RAM), a hard disk drive, a Compact Disc (CD), a Digital Video Disc (DVD), or any other type of memory. A "non-transitory" computer-readable medium does not include a wired, wireless, optical, or other communication link that transports transitory electrical or other signals. Non-transitory computer readable media include media that can permanently store data and media that can store data and then be overwritten (such as rewritable optical disks or erasable memory devices).

Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

Advantageous effects

According to the embodiments of the present disclosure, in any type of washing machine, the amount of laundry introduced into the washing machine can be measured with high accuracy in a short time. Therefore, more effective water saving can be expected.

Drawings

For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, wherein like reference numbers represent like parts:

fig. 1 illustrates a schematic cross-sectional view of a main structure of a washing machine according to an embodiment of the present disclosure;

fig. 2 illustrates a schematic diagram of a structure of a driving unit;

fig. 3 illustrates a control block diagram of a washing machine according to an embodiment of the present disclosure;

FIG. 4 illustrates a graph representing a linear relationship between acceleration and rotational speed;

FIG. 5 illustrates a graph representing the relationship between acceleration and motor temperature;

fig. 6 illustrates a graph representing a change in the rotation speed of a spin basket for measuring the weight of laundry;

fig. 7 is a flowchart illustrating a control method of a washing machine according to an embodiment of the present disclosure;

fig. 8A and 8B are flowcharts illustrating a method of determining the weight of laundry according to an embodiment of the present disclosure; and

fig. 9A and 9B are flowcharts illustrating a method of determining the weight of laundry according to an embodiment of the present disclosure.

Detailed Description

Fig. 1 through 9B, discussed below, and the various embodiments used to describe the principles presently disclosed in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device.

Embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The embodiments are merely examples and are not limited thereto.

Fig. 1 illustrates a schematic cross-sectional view of a main structure of a washing machine according to an embodiment of the present disclosure. Referring to fig. 1, a washing machine 1 is a fully automatic top loading washing machine. At the direction of the user, a series of processes such as washing, rinsing, spin-drying, etc. are automatically performed. The washing machine 1 may include a main body 2 shaped like a vertically long box, and an operator 3 provided with switches or buttons arranged thereon on the top and rear of the main body 2. An instruction of the user is received through the operator 3.

An opening covered by a door 2a that can be opened or closed is formed in the main body 2 in front of the operator 3. Through which laundry such as clothes is introduced into the main body 2. A fixed barrel 4 capable of storing water is installed in the main body 2. The stationary tub 4 is a cylindrical container having a bottom. An inlet 4a is formed on the top of the fixed tub 4 to face the opening. A drainage system 5 and a driving system 6 are provided under the stationary tub 4. The drive system 6 may be referred to as a drive unit 6.

The stationary tub 4 may fluctuate because the stationary tub 4 is suspended from the main body 2 by the wire 7. A water supply system 8 connected to an external water source is provided in an upper portion of the main body 2. The water supply system 8 includes a water supply valve 8a and a water supply pipe 8 b. When the water supply valve 8a is opened, water is automatically supplied into the stationary tub 4.

The spinning tub 9 is accommodated in the fixed tub 4. The spin basket 9 can rotate about a vertical axis a. The spin basket 9 is shaped like a cylindrical container having a bottom, and an inlet port 9a is formed at the top of the spin basket 9. The spin basket 9 is accommodated in the fixed basket 4 such that an inlet port 9a of the spin basket 9 faces the inlet port 4 a. Accordingly, the laundry is introduced into the spin basket 9 through the inlet 4a and the inlet port 9 a.

A plurality of through holes 9b are formed on the side surface of the spin basket 9. A ring balancer 10 is installed at the top of the spin basket 9 to keep the spin basket 9 balanced during high-speed rotation. A disk impeller 11 is installed at the bottom of the spin tub 9.

The drain system 5 includes a drain valve 5a, a drain pipe 5b, and the like, and the drain system 5 is connected to a drainable hole formed at the bottom of the stationary tub 4. When the drain valve 5a is opened for draining, the water contained in the fixed tub 4 is released from the washing machine 1 by natural drainage due to gravity.

The drive system 6 includes a motor 60, an inverter 61, a power transmitter 62, and the like. The drive system 6 may be referred to as a drive unit 6. The drive system 6 rotates the pulsator 11 and the spin basket 9 by using the motor 60 as a power source. As shown in fig. 2, the motor 60 is connected to an external power source PS through an inverter 61. Generally, the external PS is a commercial Alternating Current (AC) power source, and in the embodiment of the present disclosure, the inverter 61 may include a converter. Thus, the inverter 61 may be connected to a Direct Current (DC) PS or an AC PS and may perform voltage conversion.

In the inverter 61, there is a common circuit including a plurality of switching devices such as Insulated Gate Bipolar Transistors (IGBTs), a plurality of free wheeling diodes (free wheeling diodes) connected in anti-parallel with the switching devices, three arms on which the switching devices and the freewheeling diodes are arranged, and the like. The inverter 61 converts the DC voltage converted by turning on and off the switching devices of each arm into three AC voltages of different phases U, V, W, and outputs the AC voltages.

In an embodiment, the motor 60 is an induction motor (asynchronous motor). The motor 60 includes a cylindrical stator 60b equipped with a plurality of coils 60a, and a cargo-like rotor 60c rotatably disposed inside the stator 60 b. Fig. 2 illustrates a simplified version of the motor 60.

When AC currents of different phases flow in the coil 60a, magnetic fields of different phases are generated around the stator 60 b. The rotor 60c is rotated at a speed lower than the synchronous speed due to an induction current generated by the magnetic field. That is, the motor 60 generates "slip" while being rotated.

In an embodiment, the motor 60 is a three-phase motor. In this case, the three-phase AC current output from the inverter 61 is input to the motor 60. The motor 60 is driven by three-phase AC current. As shown in fig. 1, the primary pulley 63 is coupled to an output shaft of the motor 60.

The power transmission system 62 includes a secondary pulley 620, a clutch 621, a conversion mechanism portion 622, and the like. The power transmission system 62 is installed under the stationary tub 4 such that the center of the power transmission system 62 is aligned with the vertical axis a. The conversion mechanism portion 622 includes an input shaft 622a protruding downward, a first vertical power shaft 622b penetrating the bottom of each of the stationary tub 4 and the spin tub 9 and having a front end fixed to the pulsator 11, and a second vertical power shaft 622c fixed to the bottom of the spin tub 9.

The secondary pulley 620 is mounted at the input shaft 622 a. The secondary pulley 620 and the primary pulley 63 are coupled by a variable belt 64. Thus, the driving force of the motor 60 is transmitted to the power transmission system 62 through the variable belt 64.

The shifter portion 622 is switchable between a "wash/rinse mode" in which the input shaft 622a is decoupled from the second vertical power shaft 622c and couples the input shaft 622a to the first vertical power shaft 622b, and a "spin-dry mode" in which the input shaft 622a is decoupled from the first vertical power shaft 622b and couples the input shaft 622a to the second vertical power shaft 622 c. That is, when the motor 60 rotates in the washing/rinsing mode, the pulsator 11 rotates, and when the motor 60 rotates in the spin-drying mode, the spin basket 9 rotates.

A clutch 621 is interposed between the input shaft 622a and the second vertical power shaft 622c for switching the connection state between the input shaft 622a and the second vertical power shaft 622 c. Specifically, the clutch 621 switches between a connected state ("connected") in which the input shaft 622a and the second vertical power shaft 622c are connected to connect the motor 60 and the spin tub 9, and a disconnected state ("disconnected") in which the input shaft 622a is decoupled from the second vertical power shaft 622c to disconnect the motor 60 and the spin tub 9.

When the spin basket 9 rotates at a constant speed or acceleration, the clutch 621 is pressed by the elastic force of the spring to be in a connected state. When the spin basket 9 is slowed down, the clutch 621 automatically switches the spin basket 9 to a disconnected state (spring clutch method).

The control system 20 is mounted in the upper part of the main body 2. The control system 20 controls the general operation of the washing machine 1. The control system 20 includes hardware components such as a processor (e.g., a Central Processing Unit (CPU)), a memory, and the like. The memory stores software such as a control program or different types of data. The processor included in the control system may create control signals to control the operation of the washing machine 1 based on the control programs and data stored in the memory. The processor and the memory may be implemented in separate chips or in a single chip. Further, the control system 20 may include at least one processor and at least one memory.

Fig. 3 illustrates key components of the control system 20. The control system 20 is electrically connected to the current sensor 12, the voltage sensor 13, the operator 3, the drive system 6, the water supply valve 8a, the drain valve 5a, and the like. The current sensor 12 measures the current output from the motor 60 and transmits the measured value to the control system 20. The voltage sensor 13 measures the voltage output from the motor 60 and transmits the measured value to the control system 20. The operator 3 transmits information indicating the start of operation, selection of an operation mode, and the like to the control system 20. The control system 20 controls the drive system 6, the water supply valve 8a, the drain valve 5a, and the like based on the measured values and the instruction information.

The control system 20 comprises a default processor 21, a laundry weight measurer 22, a temperature corrector 23 and an information memory 24. The default processor 21 performs a series of processes such as washing, rinsing, spin-drying, etc. under instruction. The laundry weight measurer 22 measures and/or identifies the weight of the laundry introduced into the spin tub 9 at the start of the washing process (laundry weight measuring process). The temperature corrector 23 performs a temperature correction process corresponding to the temperature of the motor 60 for the laundry weight measuring process. The information memory 24 stores basic information, temperature correction information, and the like, which will be described later, and transmits the information to the laundry weight measurer 22, the temperature corrector 23, and the like. The information memory 24 corresponds to a memory. The processes performed by the default processor 21, the laundry weight measurer 22, and the temperature corrector 23 may be performed by at least one processor.

Water is automatically supplied in each of the washing and rinsing processes. In order to obtain a sufficient washing effect and to efficiently save water, it is necessary to determine a sufficient amount of water according to the weight of the laundry. For this, the laundry weight measurer 22 performs the laundry weight measuring process by measuring and/or determining the weight of the laundry introduced into the spin tub 9 at the start of the washing process.

When the spin basket 9 slows down, the spin basket 9 is automatically decoupled from the motor 60 and enters the free state. Since the mechanical load is different during acceleration and deceleration and it is difficult to measure the rotation speed and acceleration during deceleration, the washing machine 1 cannot measure the weight of laundry using the rotation state change during deceleration.

In the embodiment, the washing machine 1 may measure the weight of the laundry with high accuracy without using the change of the rotation state during deceleration. For example, the washing machine 1 rotates a spin tub 9 (also referred to as a laundry-loaded spin tub 9) loaded with laundry by applying torque to the spin tub 9, and measures the weight of the laundry based on acceleration and rotation speed during constant-speed rotation of the spin tub 9 loaded with the laundry.

When the spin basket 9 loaded with the laundry is rotated at a certain torque by the driving of the motor 60, the spin basket 9 loaded with the laundry is engaged and accelerated with the output of the motor 60 and then rotated at a constant speed corresponding to the torque. In this case, the acceleration and the rotation speed of the spin basket 9 loaded with laundry are affected by mechanical losses (such as friction occurring in the drive system 6).

Therefore, when the weight of the laundry is measured based on the acceleration and the rotation speed without reflecting the mechanical loss, the measurement may be inaccurate. The acceleration and the rotation speed affected by the mechanical loss have a predefined linear relationship associated with the magnitude of the load applied to the spin basket 9.

Fig. 4 illustrates an example of a linear relationship existing between acceleration and rotation speed. The vertical axis represents acceleration, and the horizontal axis represents rotation speed. The straight lines L1 to L4 represent a linear relationship between the acceleration and the rotation speed for different magnitudes of loads applied to the spin basket 9. The load of L1 was 4kg, L2 was 2kg, L3 was 1kg, and L4 was 0 kg.

The acceleration and the rotation speed are affected by mechanical loss, and have a linear relationship defined as α (acceleration) ═ k (coefficient) × ω (rotation speed) + Z, depending on the magnitude of the load applied to the spin basket 9.

As shown in fig. 4, the load applied to the spin basket 9 has a proportional relationship with Z. That is, Z (α -k · ω) is proportional to the load applied to the spin basket 9. Thus, based on this relationship, the load applied to the spin basket 9 can be calculated.

For example, each load Z shown in FIG. 4 is compared to a value calculated from the measured Z. Thus, it is determined whether the load applied to the spin basket 9 is in the range of 0 to 1kg, 1kg to 2kg, 2kg to 4kg, or 4kg or more, and the weight of the laundry is identified based on the determination.

The coefficient k varies depending on the driving voltage or frequency. Information on the linear relationship is obtained through experiments and stored as basic information in the information storage 24.

The detection of acceleration is susceptible to temperature. In particular, for induction motors, acceleration and rotational speed vary with temperature while rotating, which may affect measurement accuracy. In the embodiment, the washing machine 1 may perform temperature correction even during the laundry weight measurement.

Fig. 5 illustrates the relationship between acceleration and motor temperature. The acceleration and the motor temperature also have a linear relationship associated with the magnitude of the load applied to the spin basket 9. The straight lines L5 to L7 represent a linear relationship between the acceleration and the motor temperature for different loads applied to the spin basket 9. The load of L5 was 4kg, the load of L6 was 2kg, and the load of L7 was 1 kg. Although not shown, a similar linear relationship exists between the rotational speed of the motor 60 and the temperature.

Information on the linear relationship is obtained by experiment and stored in the information memory 24 as temperature correction information. The temperature corrector 23 corrects the acceleration and the rotation speed (second rotation speed) of the spin basket 9 loaded with laundry according to the temperature of the motor 60 based on the temperature correction information. Thus, an accurate laundry weight measuring process is possible.

The motor temperature may be measured by, for example, a temperature sensor installed at the motor 60. However, in this case, the need for newly providing the temperature sensor may cause an increase in product cost or an increase in the number of manufacturing processes. In the embodiment of the present disclosure, the washing machine 1 indirectly measures the temperature of the motor 60 without using a temperature sensor.

For example, the temperature of the motor 60 is measured by using a linear relationship between the temperature of the coil 60a and the resistance. Specifically, the information memory 24 stores in advance information (resistance information) regarding a linear relationship between the temperature and the resistance of the motor 60. Resistance information may be obtained experimentally. In the laundry weight measuring process, the control system 20 controls the inverter 61 to perform a temperature measuring process of applying a predefined DC voltage to the coil 60 a.

The resistance R of the coil 60a, the DC current I flowing in the coil 60a, and the DC voltage V applied across the coil 60a have a relationship of R ═ V/I. When the temperature measurement process is performed, the control system 20 identifies the resistance of the coil 60a by substituting the measurements obtained from the current sensor 12 and the voltage sensor 13 into the equation. The control system 20 identifies the motor temperature by comparing the identified resistance with the resistance information.

The acceleration and rotational speed of the motor 60 may be measured by an instrument device such as, for example, a resolver or a rotary encoder installed at the motor 60. However, in this case, the need for newly setting up the instrumentation leads to an increase in the product cost or an increase in the number of manufacturing processes. Therefore, in the embodiment of the present disclosure, the washing machine 1 indirectly measures the acceleration and the rotation speed of the motor 60.

For example, the control system 20 obtains current values Id and Iq by performing α β conversion and dq conversion on the current value Iu of the phase U, Iv of the phase V, and Iw of the phase W received from the current sensor 12 while the motor 60 is rotating. The rotational frequency ω s due to the slip is obtained by calculating Iq/Id. The rotation speed ω of the spin basket 9 is obtained by subtracting the rotation frequency ω s (ω i — ω s) due to the slip from the frequency ω i of the voltage for driving the motor 60.

As such, the control system 20 obtains the acceleration and the rotational speed of the motor 60 by performing an arithmetic operation based on the value received from the current sensor 12 without requiring an instrument device.

Fig. 6 illustrates the change in the rotation speed of the spin basket 9 with time, which is used to measure the weight of the laundry.

The control system 20 (in particular the laundry weight measurer 22) controls the inverter 61 from the state in which the spin tub 9 loaded with laundry is stopped (torque control). Since a certain amount of torque (first torque) is applied to the spin basket 9 loaded with laundry, the spin basket 9 loaded with laundry is gradually accelerated and stabilized at the highest rpm at which the first torque can be reached, and is rotated at a constant speed (first rpm) of the rpm (first constant speed rotation process). The first rpm refers to the first rotational speed.

The control system 20 applies an AC current having a first voltage and a first frequency to the motor 60. For example, an AC current having a frequency of 120V and targeted at 250rpm is applied to the motor 60. The spin tub 9 loaded with the laundry is accelerated accordingly and then rotated at a constant speed of the first rotation speed of about 200 rpm.

The control system 20 applies a second torque, which is greater than the first torque, to the spin basket 9 so as to rotate the spin basket 9 rotating at the first rotation speed at a second rotation speed higher than the first rotation speed (second constant speed rotation process).

In fig. 6, after the first constant speed rotation becomes stable for about 6 seconds, the frequency of the AC current is changed to a second frequency targeting 500rpm, and a second torque is applied to the spin basket 9 loaded with laundry. For the second constant speed rotation, the second voltage applied to the motor 60 may be equal to the first voltage. Thus, the spin basket 9 is accelerated and then rotated at a constant speed of a second rotation speed, which is about 490 rpm.

The control system 20 obtains the acceleration at the time of the change from the first rotational speed to the second rotational speed and the second rotational speed for the second constant speed rotation.

The acceleration can be obtained by using the acceleration portion 1a having high linearity (about 2 seconds). For example, the acceleration may be obtained by measuring the velocities at the beginning and end of the acceleration period 1a and dividing them by the elapsed time. A plurality of velocities in the acceleration period 1a may be measured, and the acceleration may be obtained by a first approximation.

Further, the second rotation speed can be obtained when the spin basket 9 is somewhat stable. In fig. 6, the second rotation speed is measured in the stable portion 1v (about 1 second) within 10 minutes after the start of the second constant speed rotation process. The second rotation speed may be obtained by performing measurements several times and averaging the measurements.

Since the motor 60 is an asynchronous motor, the control system 20 drives the motor 60 at a predefined voltage and frequency to apply a certain torque to the spin tub 9 loaded with laundry. The second voltage for the second constant speed rotation process may be higher than the first voltage for the first constant speed rotation process. This results in higher acceleration and may reduce the time required for the measurement. In this case, the second frequency for the second constant speed rotation process may be equal to the first frequency for the first constant speed rotation process.

As such, the control system 20 obtains the acceleration and rotational speed of the motor 60. Subsequently, the control system 20 may perform temperature correction and mechanical loss correction on the obtained acceleration and rotation speed, and measure the weight of the laundry.

Fig. 7 illustrates a flowchart of a control method of a washing machine according to an embodiment of the present disclosure, and fig. 8A and 8B illustrate a flowchart of a method of determining the weight of laundry according to an embodiment of the present disclosure.

Referring to fig. 7, in S1, laundry is first introduced into the spin tub 9 when a washing course is performed. The detergent is put into the washing machine 1 together with the laundry. In S2, an instruction to start washing is input through the operator 3. The control system 20, in particular the default processor 21, automatically performs a series of washing, rinsing and spinning processes according to the instructions.

At the beginning of the washing process, the control system 20 (particularly the laundry weight measurer 22) performs a laundry weight measuring process to determine an appropriate amount of water supply in S3. Fig. 8A and 8B show details of the method.

In S301, the control system 20 (particularly, the temperature corrector 23) performs a temperature measurement process. Specifically, as described above, the control system 20 controls the inverter 61 to apply a predefined DC voltage to the coil 60a and measure the actual resistance of the coil 60 a. The control system 20 identifies the temperature of the motor 60 by comparing the measured actual resistance to the resistance information.

Subsequently, in S302, the control system 20 controls the power transmission system 62 to switch the switch mechanism portion 622 to the spin-drying mode. When the motor 60 is driven accordingly, the spin basket 9 is also rotated.

As shown in fig. 6, in S303, the control system 20 controls the inverter 61 to apply a first torque to the spin basket 9, thereby driving the motor 60 at a first voltage and a first frequency. When the rotation speed of the spin basket 9 is stabilized at the first rotation speed for a certain time in S304, the control system 20 controls the inverter 61 to apply the second torque to the spin basket 9 in S305, thereby driving the motor 60 with the second voltage and the second frequency. The second voltage may be equal to the first voltage, and the second frequency may be higher than the first frequency. Alternatively, the second voltage may be higher than the first voltage, and the second frequency may be equal to the first frequency. As such, the voltage and frequency applied to the motor 60 may be separately controlled.

In S306 and S307, the control system 20 detects acceleration using the acceleration portion. When the spin basket 9 is stabilized at the second rotation speed for a certain time in S308, the control system 20 detects the second rotation speed (end speed) in S309.

In S310, the control system 20 estimates the amount of laundry based on the temperature, acceleration, and rotational speed of the motor 60.

The control system 20 compares the estimated laundry amount W with the weight difference values stored in the information storage 24 (herein, there are three weight difference values A, B and C.C ≧ B ≧ A based on the relationship of FIG. 4).

When the amount W of laundry estimated in S311 is less than the weight difference value a, the control system 20 recognizes that the amount of laundry is 0kg in S312.

When the estimated amount W of laundry is equal to or greater than the weight difference value a in S311, the control system 20 compares the estimated amount W of laundry with the weight difference value B in S313. When the amount W of laundry estimated in S313 is less than the weight difference value B, the control system 20 recognizes that the amount of laundry is 1kg in S314.

When the estimated amount W of laundry is equal to or greater than the weight difference value B in S313, the control system 20 compares the estimated amount W of laundry with the weight difference value C in S315. When the amount W of laundry estimated in S315 is less than the weight difference value C, the control system 20 identifies that the amount of laundry is 2kg in S316, and when the amount W of laundry estimated in S315 is equal to or greater than the weight difference value C, the control system 20 identifies that the amount of laundry is 4kg in S317.

Once the control system 20 recognizes the amount of laundry, water supply is started in S4, as shown in fig. 7.

The information storage 24 stores water supply information that enables setting of a water supply amount corresponding to the amount of laundry. The control system 20 selects an appropriate water supply amount by comparing the recognized amount of laundry with the water supply information. The control system 20 controls the water supply valve 8a to supply as much water as the selected water supply amount to the fixed tub 4.

When the water supply is completed, the control system 20 starts the washing process in S5. During the washing process, the switching mechanism portion 622 switches the washing machine 1 from the spin-drying mode to the washing/rinsing mode. The pulsator 11 is driven to rotate at a low speed for a predetermined time to agitate the laundry. After that, the drain valve 5a is controlled to release water from the fixed tub 4, and the washing process is ended.

When the washing process is finished, the control system 20 starts the rinsing process in S6. Even in the rinsing process, water supply, agitation, and drainage are performed as in the washing process. The rinsing process may be performed several times.

When the rinsing course is finished, the control system 20 starts the spin-drying course in S7. During the spinning, the switching mechanism portion 622 switches the washing machine 1 from the washing/rinsing mode to the spinning mode. The spinning drum 9 is driven to rotate at a high speed for a predetermined time to dehydrate the laundry. The water collected into the fixed tub 4 due to the spinning is drained through the drainage system 5.

When the spinning process is finished, the control system 20 informs the user, for example by means of a buzzer, that the laundry has been washed out.

In the embodiment, it is assumed that the motor 60 is an asynchronous motor. However, the present disclosure is also applicable to synchronous machines. In the embodiment, it is assumed that the motor 60 is a synchronous motor.

The structure of the washing machine 1 is the same as that of the previous embodiment except that the motor 60 is a synchronous motor. Thus, the description of the same parts will be omitted or simplified, and different parts will be described.

The motor 60 is, for example, a permanent magnet type motor (synchronous motor). The rotor 60c includes a plurality of permanent magnets constituting a plurality of magnetic poles. With the motor 60, when AC currents of different phases flow in each coil 60a, the rotor 60c rotates at a (synchronous) speed synchronized with the AC currents (no slip occurs).

Thus, the control system 20 controls the inverter 61 to apply a specific torque to the spin basket 9, thereby adjusting the current to drive the motor 60. In other words, the control system 20 may drive the motor 60 at a predefined current.

Fig. 9A and 9B are flowcharts illustrating a method of determining a laundry weight according to another embodiment of the present disclosure. The embodiment of fig. 9A and 9B overlaps with some of the previous embodiments of fig. 8A and 8B. Thus, by using the same reference numerals, the description of the overlapped parts will not be repeated or will be simplified.

The control system 20 performs a temperature measuring process in S301 and then switches the switching mechanism portion 622 to the spin-drying mode in S302.

In S401, the control system 20 controls the inverter 61 to apply a first torque to the spin basket 9, thereby driving the motor 60 with a first current. When the rotation speed of the spin basket 9 is stabilized at the first rotation speed at a certain time in S304, the control system 20 controls the inverter 61 to apply the second torque to the spin basket 9 in S402, thereby driving the motor 60 with the second current.

The subsequent steps (S306 to S317) are the same as in fig. 8A and 8B. By replacing the target body to be controlled to apply a certain torque to the spin basket 9, the present disclosure is applicable to both asynchronous motors and synchronous motors.

The present disclosure is not limited to the foregoing embodiments but includes other various embodiments. For example, the washing machine is not limited to a top-loading washing machine. The washing machine may also be a drum washing machine with a horizontal or inclined axis of rotation.

The type of the washing machine 1 is not limited to the type in which the motor indirectly drives the spin tub like the washing machine 1 employing the above-described spring clutch method. The present disclosure may also be applied to a direct drive type washing machine in which a motor directly drives a spin tub.

Further, the present disclosure is also suitable for a simple belt-driven washing machine, in addition to the spring clutch type washing machine. Specifically, in the washing machine in which the driving force of the motor is transmitted to the spin basket through the variable belt, the motor rpm and the spin basket rpm may not correspond to each other due to, for example, the slip of the variable belt. Therefore, the disclosed technology is effective even for a belt-driven washing machine.

The laundry weight measuring process may be performed several times, and the weight of the laundry may be identified based on the plurality of measurement results. This enables the weight of the laundry to be determined more accurately. In this case, the torque applied to the spin basket may vary. Further, the rotation speed may use the first rpm instead of the second rpm.

In case that the laundry weight measuring process is performed several times, the same procedure may be repeated, or different procedures of acceleration and rotation speed may be measured by gradually increasing rpm, that is, a first constant speed rotation process, a second constant speed rotation process, a third constant speed rotation process, etc. are sequentially performed.

The motor temperature may be measured by a temperature sensor. The acceleration or rotation speed of the spin basket may actually be measured by a sensor. The motor may be a two-phase motor or a one-phase motor as well as a three-phase motor.

While the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. The present disclosure is intended to embrace such alterations and modifications as fall within the scope of the appended claims.

Claims

1. A washing machine comprising:

a spin tub provided to be rotatable and into which laundry is introduced;

a drive system including a motor and configured to rotate the spin basket; and

at least one processor configured to:

the driving unit is controlled to rotate the spin basket at a first rotational speed,

controlling the driving unit to rotate the spin basket at a second rotation speed, and

the weight of the laundry is identified based on the second rotation speed and an acceleration when the rotation speed of the spin tub is changed from the first rotation speed to the second rotation speed.

2. The washing machine as claimed in claim 1, further comprising:

at least one memory for storing at least one of the data,

wherein the at least one memory stores basic information including linear relationship information between an acceleration and a second rotation speed, the linear relationship information being associated with a magnitude of a load applied to the spin bucket, and

wherein the at least one processor is configured to identify the weight of the laundry based on the acceleration, the second rotational speed, and the basic information.

3. The washing machine as claimed in claim 1, wherein the motor is an asynchronous motor, and

wherein the at least one processor is configured to control the drive unit to drive the motor at a first voltage and a first frequency such that the spin tub is rotated at a first rotational speed, and to control the drive unit to drive the motor at a second voltage and a second frequency such that the spin tub is rotated at a second rotational speed.

4. The washing machine as claimed in claim 3, wherein the driving unit includes an inverter for controlling driving of the motor, and

wherein the at least one processor is configured to obtain the acceleration and the second rotational speed based on a current output from the inverter to the motor.

5. The washing machine as claimed in claim 1, wherein the motor is a synchronous motor, and

wherein the at least one processor is configured to control the drive unit to drive the motor at a first current such that the spin tub is rotated at a first rotational speed, and to control the drive unit to drive the motor at a second current such that the spin tub is rotated at a second rotational speed.

6. The washing machine as claimed in claim 1, further comprising: at least one memory for storing at least one of the data,

wherein the memory stores temperature correction information including information of a linear relationship between each of the acceleration and the second rotation speed and the temperature of the motor, and

wherein the at least one processor is configured to correct the acceleration and the second rotational speed based on the temperature correction information.

7. The washing machine as claimed in claim 6, wherein the at least one processor is configured to identify the temperature of the motor based on the resistance of the coil of the motor and resistance information stored in the memory.

8. The washing machine as claimed in claim 7, wherein the at least one processor is configured to control the drive unit to apply a predefined Direct Current (DC) voltage to the coil and to measure a resistance of the coil.

9. The washing machine of claim 1, wherein the at least one processor is configured to measure the weight of the laundry a plurality of times and identify the weight of the laundry based on the plurality of measurements.

10. The washing machine as claimed in claim 9, wherein the at least one processor is configured to control the drive unit to rotate the spin tub at a different speed for each of the plurality of times.

11. The washing machine as claimed in claim 1, wherein the driving unit includes a clutch for switching between a connection state in which the motor and the spin tub are connected and a disconnection state in which the motor and the spin tub are disconnected, and

wherein the clutch switches the spin basket from the connected state to the disconnected state when the spin basket decelerates.

12. The washing machine as claimed in claim 1, wherein the driving unit includes a variable belt interposed between the motor and the spin basket for transmitting a driving force of the motor to the spin basket.

13. The washing machine as claimed in claim 1, wherein the at least one processor is configured to control the drive unit to rotate the spin tub at a first rotational speed by applying a first torque and then to rotate the spin tub at a second rotational speed by applying a second torque greater than the first torque.