Washing machine and control method of the same

Abstract

To provide a washing machine capable of suppressing dispersion of water to the outside of a washing tub in a water supply rotation operation.SOLUTION: A washing machine includes: a washing tub in which laundry is stored; water supply means for performing water supply into the washing tub; a motor for rotating the washing tub; a motor drive circuit for driving the motor; and a control device. The control device executes a water supply rotation operation which is the operation of performing water supply to the washing tub while rotating the washing tub. The control device includes: a cloth amount detection part for detecting the cloth amount which is the amount of the laundry stored in the washing tub; and a setting part for setting a current value of a control current supplied to the motor from the motor drive circuit in the water supply rotation operation, based on the cloth amount detected by the cloth amount detection part.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a washing machine and a control method thereof. [Background technology]

[0002] A washing machine according to the background art is disclosed in Patent Document 1. The washing machine includes a motor, a motor drive circuit, a power supply circuit, a control unit, and a laundry amount detection unit. The power supply circuit supplies current to the motor. The control unit executes acceleration control, constant speed control, and pause control of the motor. The laundry amount detection unit detects the amount of laundry based on the average current value during constant speed control or the motor rotation angle during pause control. This allows the laundry amount to be detected easily and accurately without using a position sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7336644 Summary of the Invention [Problem to be solved by the invention]

[0004] The operation of the washing machine includes an operation of supplying water to the washing tub while rotating the washing tub at a low speed (hereinafter referred to as the "water supply rotation operation"). If the rotation speed of the washing tub becomes too fast during the water supply rotation operation, the supplied water will splash out of the washing tub, which is undesirable.

[0005] The washing machine disclosed in Patent Document 1 does not take sufficient measures to prevent water from splashing out of the washing tub during the water supply rotation operation.

[0006] An object of the present disclosure is to provide a washing machine and a control method thereof that can suppress water from splashing outside the washing tub during the water supply rotation operation. [Means for solving the problem]

[0007] A washing machine according to one aspect of the present disclosure comprises a washing tub for storing laundry, a water supply means for supplying water to the washing tub, a motor for rotating the washing tub, a motor drive circuit for driving the motor, and a control device, wherein the control device performs a water supply rotation operation which supplies water to the washing tub while rotating the washing tub, and the control device has a laundry amount detection unit which detects the amount of laundry stored in the washing tub, and a setting unit which sets the current value of the control current supplied from the motor drive circuit to the motor during the water supply rotation operation based on the amount of laundry detected by the laundry amount detection unit.

[0008] A method for controlling a washing machine according to another aspect of the present disclosure is a method for controlling a washing machine including a washing tub for storing laundry, a water supply means for supplying water to the washing tub, a motor for rotating the washing tub, and a motor drive circuit for driving the motor, wherein a control device performs a water supply rotation operation, which is an operation for supplying water to the washing tub while rotating the washing tub, detects the amount of laundry, which is the amount of laundry stored in the washing tub, and sets a current value of a control current supplied from the motor drive circuit to the motor during the water supply rotation operation based on the detected amount of laundry. [Effects of the Invention]

[0009] According to the present disclosure, splashing of water outside the washing tub during the water supply rotation operation can be suppressed. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of a main part showing a simplified configuration of a washing machine according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a simplified block diagram showing the configuration of a motor drive system. [Figure 3] FIG. 2 is a diagram showing some of the functions of a control means. [Figure 4] FIG. 2 is an equivalent circuit diagram of the motor. [Figure 5]FIG. 2 is a simplified block diagram showing the configuration of a control unit when open-loop control is performed. [Figure 6] FIG. 3 is a simplified block diagram showing the configuration of a control unit when feedback control is performed. [Figure 7] FIG. 2 is a block diagram showing a configuration of a speed phase estimation means. [Figure 8] 10 is a timing chart showing a simplified water supply rotation operation in a washing process. [Figure 9] 10 is a flowchart simply showing the process executed by the control unit in, for example, a washing process including a water supply rotation operation. [Figure 10] 10 is a timing chart showing a simplified example of setting the current value of a control current. [Figure 11] 10 is a timing chart showing, in simplified form, the rotation speed of the washing and spin-drying tub and the waveform of the current value of the control current for two successive water supply rotation operations. [Figure 12] 10 is a timing chart showing, in simplified form, the rotation speed of the washing and spin-drying tub and the waveform of the current value of the control current in a situation where the motor loses synchronism during the water supply rotation operation. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Findings that formed the basis of this disclosure) Conventional washing machines use position sensors such as Hall elements or rotary encoders to detect motor rotation (detection of rotation speed and rotation position). However, from the perspective of cost reduction and structural constraints, washing machines that control motors using a so-called sensorless method, which detects rotation without using a position sensor, have been put into practical use.

[0012] One type of sensorless method is a method that uses induced voltage. This method detects the motor current flowing through the motor, calculates the induced voltage based on the voltage applied to the motor and the motor current, and estimates the motor rotation speed based on this induced voltage.

[0013] The induced voltage is proportional to the rotational speed of the motor, so in the low-speed region where the motor rotational speed is low, the induced voltage is small and the rotational speed of the motor cannot be accurately estimated.

[0014] Therefore, the sensorless method using induced voltage has a motor control period consisting of an open-loop control period in the low-speed range and a feedback control period in the high-speed range. Open-loop control is control that does not estimate the motor rotation speed and does not feed back the estimated rotation speed value to the input side. In open-loop control, the voltage applied to the motor is controlled based on a target value of the control current (magnetic flux current or torque current) supplied to the motor and a target value of the motor rotation speed. Feedback control is control that estimates the motor rotation speed based on the induced voltage and feeds back the estimated rotation speed value to the input side. In feedback control, the control current (magnetic flux current or torque current) and the voltage applied to the motor are controlled based on the deviation between the target value of the motor rotation speed and the fed-back estimated value.

[0015] Incidentally, the operation of a vertical washing machine includes a water supply rotation operation in which water is supplied to the washing tub while the washing tub is rotating during the washing process, rinsing process, etc. In order to prevent the supplied water (tap water, detergent water, etc.) from splashing outside the washing tub, the target value of the rotation speed of the washing tub during the water supply rotation operation is set to a predetermined low speed (for example, 40 rpm).

[0016] In the washing machine according to the background art, in the open-loop control for rotating the washing tub, the target value of the control current is set to a relatively large value so that the washing tub can rotate reliably even when the maximum load of laundry is placed in the washing tub. Therefore, when the amount of laundry is small, the current value of the control current becomes too large for the amount of laundry, and the rotation speed of the washing tub becomes faster than the target value, causing the supplied water to splash out of the washing tub.

[0017] In order to solve this problem, the inventor discovered that by detecting the amount of laundry contained in the washing tub and appropriately setting the current value of the control current based on the detected amount of laundry, it is possible to prevent water from splashing outside the washing tub during the water supply rotation operation, and this finding formed the subject of the present disclosure.

[0018] Therefore, the present disclosure provides a washing machine and a control method thereof that can suppress water from splashing outside the washing tub during the water supply rotation operation.

[0019] (Embodiments of the present disclosure) Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters or redundant description of substantially the same configuration may be omitted.

[0020] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the disclosure, and are not intended to limit the subject matter described in the claims.

[0021] FIG. 1 is a cross-sectional view of a main part showing, in a simplified form, the configuration of a washing machine according to an embodiment of the present disclosure.

[0022] A washing and spin-drying tub (washing tub) 2 is disposed inside a water receiving tub 3 so as to be rotatable left and right. A pulsator 1 is disposed on the inner bottom of the washing and spin-drying tub 2 so as to be rotatable left and right. A motor 4 is disposed on the outer bottom of the water receiving tub 3. When the motor 4 rotates, its torque is transmitted to the pulsator 1 via a motor pulley 31, a belt 5, an impeller pulley 32, and a speed reducer / clutch 6. The speed reducer / clutch 6 connects or disconnects the pulsator 1 and the washing and spin-drying tub 2. This allows the motor 4 to rotate the pulsator 1 and the washing and spin-drying tub 2 together, or to rotate only the pulsator 1. Note that, in this embodiment, the rotation of the motor 4 is transmitted to the pulsator 1 and the washing and spin-drying tub 2 via the belt 5, but this is not limiting. A direct drive system may be employed in which the rotation of the motor 4 is transmitted to the pulsator 1 and the washing and spin-drying tub 2 without a belt.

[0023] A panel unit 10 is disposed on top of the washing machine's outer frame 9. A lid 11 that can be opened and closed is disposed on the top surface of the panel unit 10. A control device 13 having a display unit 12 is disposed inside the panel unit 10. The control device 13 controls all of the washing processes performed by the washing machine. The washing processes include a washing process, a rinsing process, and a spin-drying process, and the desired washing process is performed according to the washing course input by the user. The control device 13 performs the washing processes by controlling the operation of the motor 4, the reduction mechanism / clutch 6, the geared motor 7, the water supply valve 14, the drain valve 15, etc. The geared motor 7 has a brake belt 8 that mechanically brakes the rotation of the washing / spin-drying tub 2 by contacting the rotating part.

[0024] FIG. 2 is a block diagram showing a simplified configuration of the motor drive system.

[0025] The motor drive system includes a rectifier circuit 16, an inverter circuit 17, a current detection means 18, a PWM control means 19, and a control means 20. The control means 20 is configured using a microcontroller or the like. The control means 20 may be part of the functions of the control device 13.

[0026] FIG. 3 is a diagram showing some of the functions of the control means 20. As shown in FIG.

[0027] The control means 20 has a control unit 51, a laundry amount detection unit 52, a setting unit 53, an error calculation unit 54, and a correction unit 55 as functions realized by a processor such as a CPU executing a program. The control means 20 may be configured without the error calculation unit 54 and the correction unit 55. The details of the processing executed by each of these units will be described later.

[0028] Referring to Fig. 2, the rectifier circuit 16 is configured as, for example, a voltage doubler rectifier circuit. The rectifier circuit 16 voltage-doubles and rectifies an AC voltage input from an AC power supply, thereby inputting a DC voltage Vdc to the inverter circuit 17. The inverter circuit 17 is a motor drive circuit that drives the motor 4 with applied voltages Vu, Vv, and Vw, and is configured using, for example, an intelligent power module (hereinafter referred to as "IPM"). The IPM incorporates a three-phase full-bridge inverter circuit, a drive circuit, and a protection circuit. The three-phase full-bridge inverter circuit has six power switching elements such as insulated gate bipolar transistors (hereinafter referred to as "IGBTs"), and diodes connected in anti-parallel to each power switching element.

[0029] The current detection means 18 detects the current value of the motor current flowing through the motor 4 by measuring the voltage across the shunt resistor. The shunt resistor is connected to a wiring path between the negative voltage terminal of the inverter circuit 17 and the negative voltage terminal of the motor 4. The motor current includes phase currents Iu, Iv, and Iw of the motor 4. The current detection means 18 inputs the phase currents Iu, Iv, and Iw to the control means 20.

[0030] The control means 20 inputs voltage commands Vus, Vvs, and Vws for driving the three-phase motor to the PWM control means 19.

[0031] The PWM control means 19 generates a PWM signal based on the voltage commands Vus, Vvs, and Vws, and inputs the PWM signal to the inverter circuit 17 to control the switching operation of the IGBTs included in the inverter circuit 17 .

[0032] Figure 4 is an equivalent circuit diagram of motor 4. For simplicity of explanation, Figure 4 shows an example of a two-pole configuration in which one mechanical angle rotation corresponds to one electrical angle rotation. If the number of poles changes to four, eight, etc., the relationship changes to one mechanical angle rotation corresponds to two, four, etc. electrical angle rotations.

[0033] The motor 4 is a three-phase synchronous motor and has three-phase windings 4a, 4b, and 4c (U, V, and W), and a permanent magnet 4d, which is a rotor (rotor) that rotates around a rotation axis. The axis that passes through the N-pole side of the permanent magnet 4d in the positive direction is defined as the d-axis (direct axis), and the axis perpendicular to it is defined as the q-axis (quadrature axis). With these definitions, the torque of the motor 4 is primarily governed by the magnetic field in the q-axis direction. Furthermore, the phase θ (electrical angle) is the angle formed by the axis α that passes through the U-phase winding 4a and the d-axis. All phases described below are electrical angles. Note that the inductance of the winding when a voltage is applied to generate a magnetic field in the d-axis direction is defined as Ld, and the inductance in the q-axis direction is defined as Lq. In an interior magnet type three-phase synchronous motor, Ld <Lqとなる。

[0034] The washing machine according to this embodiment is a sensorless washing machine using induced voltage. As described above, the sensorless method using induced voltage has a control period for the motor 4, which is an open-loop control period in the low-speed range and a feedback control period in the high-speed range. Open-loop control is control in which the rotational speed of the motor 4 is not estimated and the estimated value of the rotational speed is not fed back to the input side. In open-loop control, the voltage applied to the motor 4 is controlled based on a target value of the control current (magnetic flux current or torque current) supplied to the motor 4 and a target value of the rotational speed of the motor 4. In feedback control, the rotational speed of the motor 4 is estimated based on the induced voltage and the estimated value of the rotational speed is fed back to the input side. In feedback control, the control current (magnetic flux current or torque current) and the voltage applied to the motor 4 are controlled based on the deviation between the target value of the rotational speed of the motor 4 and the fed-back estimated value.

[0035] Because the sensorless system does not use a position sensor, the control unit 20 cannot accurately detect the rotor position. In particular, in open-loop control, the rotational speed of the motor 4 is not estimated, and the estimated rotational speed value is not fed back to the input side. Therefore, the control unit 20 assumes the rotor position to be a phase θc, and an error Δθ occurs between the phase θc and the phase θ. Therefore, the axis controlled by the control unit 20 assuming the phase θc is the γ-axis (estimated d-axis) relative to the d-axis, and the δ-axis (estimated q-axis) relative to the q-axis. Hereinafter, the current component corresponding to the d-axis magnetic flux current is referred to as the γ-axis current Iγ, and the current component corresponding to the q-axis torque current is referred to as the δ-axis current Iδ. Furthermore, the command voltage component corresponding to the d-axis magnetic flux is referred to as the γ-axis voltage command Vγs, and the command voltage component corresponding to the q-axis torque is referred to as the δ-axis voltage command Vδs.

[0036] FIG. 5 is a simplified block diagram showing the configuration of the control unit 51 when open-loop control is performed.

[0037] The phase calculation means 30 receives a speed command ωs corresponding to a target value for the rotational speed of the motor 4 and an initial phase θinit of the motor 4. The phase calculation means 30 calculates the phase θ by integrating the phase per unit time based on the initial phase θinit and the speed command ωs set for each unit time. Since open-loop control does not perform speed estimation, the speed command ωs is treated as the speed ω as is. The phase calculation means 30 inputs the phase θ to the three-phase to two-phase converter 22 and the two-phase to three-phase converter 25.

[0038] The phase θ and the phase currents Iu, Iv, and Iw are input to the three-phase to two-phase converter 22. The three-phase to two-phase converter 22 calculates the δ-axis current Iδ and the γ-axis current Iγ using the following equation (1) based on the phase θ, the phase currents Iu, Iv, and Iw, and sine wave data required for conversion from the stationary coordinate system to the rotating coordinate system.

[0039]

number

[0040] The Iδ error amplifier 23 receives an error ΔIδ between the δ-axis current Iδ and a δ-axis current command Iδs corresponding to the target value of the control current. The Iδ error amplifier 23 calculates a δ-axis voltage command Vδs as the sum of a proportional component and an integral component. The Iδ error amplifier 23 inputs the δ-axis voltage command Vδs to a two-phase to three-phase converter 25.

[0041] An error ΔIγ between a γ-axis current command Iγs corresponding to a target value of the control current and the γ-axis current Iγ is input to the Iγ error amplifier 24. The Iγ error amplifier 24 calculates a γ-axis voltage command Vγs as the sum of a proportional component and an integral component. The Iγ error amplifier 24 inputs the γ-axis voltage command Vγs to a two-phase to three-phase converter 25.

[0042] At least one of the δ-axis current command Iδs and the γ-axis current command Iγs corresponds to the control current supplied from the inverter circuit 17 to the motor 4 during the open-loop control period.

[0043] The phase θ, a δ-axis voltage command Vδs, and a γ-axis voltage command Vγs are input to the two-phase to three-phase converter 25. The two-phase to three-phase converter 25 calculates sinusoidal voltage commands Vus, Vvs, and Vws using the following equation (2) based on the phase θ, the δ-axis voltage command Vδs, the γ-axis voltage command Vγs, and sinusoidal wave data required for inverse transformation from the rotating coordinate system to the stationary coordinate system.

[0044]

number

[0045] The two-phase to three-phase converter 25 inputs voltage commands Vus, Vvs, and Vws to the PWM control means 19 .

[0046] FIG. 6 is a simplified block diagram showing the configuration of the control unit 51 when feedback control is performed.

[0047] The speed phase estimation means 21 receives the initial phase θinit of the motor 4, the δ-axis current Iδ, the γ-axis current Iγ, and the γ-axis voltage command Vγs.

[0048] FIG. 7 is a block diagram showing the configuration of the speed phase estimation means 21. As shown in FIG.

[0049] The speed phase estimation means 21 has a γ-axis induced voltage calculator 28 and a γ-axis induced voltage error amplifier 29. The γ-axis induced voltage calculator 28 calculates the γ-axis induced voltage Veγ by the following equation (3) based on the inductance value L, the resistance value Ra, the δ-axis current Iδ, the γ-axis current Iγ, the γ-axis voltage command Vγs, and the estimated speed ω.

[0050]

number

[0051] With the γ-axis induced voltage command Veγs=0, the error ΔVeγ relative to the γ-axis induced voltage command Veγs is input to the γ-axis induced voltage error amplifier 29 .

[0052] The γ-axis induced voltage error amplifier 29 outputs an estimated speed ω calculated from the integral gain Kω, adds the estimated speed ω to a value calculated from the proportional gain Kθ, and performs time integration in an integrator to output an estimated phase θ.

[0053] Referring to FIG. 6, the speed phase estimation means 21 inputs the estimated phase θ to the three-phase to two-phase converter 22 and the two-phase to three-phase converter 25.

[0054] An error Δω between a speed command ωs corresponding to a target value of the rotation speed and an estimated speed ω is input to the speed error amplifier 26. The speed error amplifier 26 calculates a δ-axis current command Iδs as the sum of a proportional component and an integral component.

[0055] The field-weakening setting means 27 receives the estimated speed ω and the DC voltage Vdc input to the inverter circuit 17. The field-weakening setting means 27 calculates a γ-axis current command Iγs in the negative direction based on the estimated speed ω and the DC voltage Vdc.

[0056] An error ΔIδ between the δ-axis current command Iδs and the δ-axis current Iδ is input to the Iδ error amplifier 23. The Iδ error amplifier 23 calculates a δ-axis voltage command Vδs as the sum of a proportional component and an integral component. The Iδ error amplifier 23 inputs the δ-axis voltage command Vδs to a two-phase to three-phase converter 25.

[0057] An error ΔIγ between the γ-axis current command Iγs and the γ-axis current Iγ is input to the Iγ error amplifier 24. The Iγ error amplifier 24 calculates a γ-axis voltage command Vγs as the sum of a proportional component and an integral component. The Iγ error amplifier 24 inputs the γ-axis voltage command Vγs to a two-phase to three-phase converter 25.

[0058] At least one of the δ-axis current command Iδs and the γ-axis current command Iγs corresponds to the control current supplied from the inverter circuit 17 to the motor 4 during the feedback control period.

[0059] The two-phase to three-phase converter 25 receives the estimated phase θ, the δ-axis voltage command Vδs, and the γ-axis voltage command Vγs. The two-phase to three-phase converter 25 calculates the sinusoidal voltage commands Vus, Vvs, and Vws using the above equation (2) based on the estimated phase θ, the δ-axis voltage command Vδs, the γ-axis voltage command Vγs, and sine wave data required for inverse transformation from the rotating coordinate system to the stationary coordinate system. The two-phase to three-phase converter 25 inputs the voltage commands Vus, Vvs, and Vws to the PWM control means 19.

[0060] As described above, the operation of the vertical washing machine includes a water supply rotation operation during the washing process, rinsing process, etc. In the water supply rotation operation, water is supplied to the washing and spin-drying tub 2 by a water supply means including a water supply valve 14 while the washing and spin-drying tub 2 is rotated by the motor 4. In order to prevent the supplied water (tap water, detergent water, etc.) from splashing outside the washing and spin-drying tub 2, the target value of the rotation speed of the washing and spin-drying tub 2 during the water supply rotation operation is set to a predetermined low speed (40 rpm in the following example).

[0061] FIG. 8 is a timing chart showing the water supply rotation operation in the washing cycle. In the example shown in FIG. 8, a total of three water supply rotation operations S1 to S3 are performed in the washing cycle, which includes two washing cycles followed by one rinsing cycle. The rotation direction of washing / spin-drying tub 2 may include both left and right directions, and the target rotation speed R0 and execution period may be different for each water supply rotation operation. Between each water supply rotation operation (for example, between water supply rotation operation S1 and water supply rotation operation S2), all or some of the following may be performed: a stirring operation that rotates pulsator 1; a water supply operation that opens water supply valve 14 to supply water into water receiving tub 3; a drainage operation that opens drain valve 15 to drain water from water receiving tub 3; and a spin-drying operation that rotates washing / spin-drying tub 2 at high speed.

[0062] FIG. 9 is a flowchart simply showing the process executed by the control means 20 in, for example, a washing step including a water supply rotation operation.

[0063] The control of the water supply rotation operation by the control means 20 includes open loop control that does not feed back an estimated value of the rotation speed of the motor 4 in a speed range where the rotation speed of the washing and spin-drying tub 2 is below a predetermined value (35 rpm in the example below), and feedback control that feeds back an estimated value of the rotation speed of the motor 4 in a speed range where the rotation speed of the washing and spin-drying tub 2 is above the predetermined value (35 rpm).

[0064] First, in step SP01, setting unit 53 acquires the laundry amount, which is the amount of laundry contained in washing and spin tub 2. Laundry amount detection unit 52 detects the laundry amount at the start of the washing operation and stores data indicating the detected laundry amount in a memory unit included in control device 13. Setting unit 53 acquires the laundry amount by reading out the data from the memory unit.

[0065] The laundry amount detection unit 52 may detect the laundry amount in any manner. For example, similar to the method disclosed in Patent Document 1, the control unit 51 may execute acceleration control, constant speed control, and pause control of the motor 4, and the laundry amount detection unit 52 may detect the laundry amount based on the average current value (average torque current) during the execution of constant speed control or the rotation angle (integrated rotation angle) of the motor 4 during the execution of pause control. Alternatively, similar to the method disclosed in Japanese Patent Application Laid-Open No. 2014-54498, the control unit 51 may execute acceleration control and deceleration control of the motor 4, and the laundry amount detection unit 52 may detect the laundry amount based on the difference between the acceleration current value supplied to the motor 4 during acceleration control and the deceleration current value supplied to the motor 4 during deceleration control. Alternatively, a weight sensor may be provided to detect the laundry amount, and the weight sensor may be used to detect the laundry amount.

[0066] Next, in step SP02, the setting unit 53 sets the current value of the control current for the water supply rotation operation based on the laundry weight acquired in step SP01. As described above, the control current is at least one of the δ-axis current command Iδs and the γ-axis current command Iγs.

[0067] FIG. 10 is a timing chart showing a simplified example of setting the current value of the control current.

[0068] The control period of the water supply rotation operation by the control means 20 includes a positioning control period (times T10 to T11), an open-loop control period (times T11 to T12), and a feedback control period (times T12 to T14). The positioning control period is a period during which positioning control is performed before open-loop control to converge the direction of the rotor of the motor 4 to a specific direction.

[0069] Positioning control is a type of open-loop control, which fixes the rotation speed (for example, 0 rpm) and phase (for example, 0°) to a predetermined value, and controls the direction of the rotor of the motor 4 to converge to a specific direction.

[0070] The open-loop control period is a period during which open-loop control is performed after the positioning control period and before the feedback control period. The open-loop control is performed by controlling the phase calculated from the rotation speed in a speed range where the rotation speed is less than a predetermined value (e.g., 35 rpm), and controls the direction of the rotor of the motor 4 to converge to a specific rotation speed.

[0071] The feedback control period is a period in which feedback control is executed after the open-loop control period. The feedback control estimates the rotation speed of the motor 4, sets a control current according to the estimated rotation speed, and controls the number of rotations.

[0072] The setting unit 53 sets the current value of the control current at the end of the open-loop control period (time T12) based on the laundry amount detected by the laundry amount detection unit 52. The setting unit 53 sets a larger current value as the laundry amount increases, and sets a smaller current value as the laundry amount decreases. For example, when the laundry amount is a first laundry amount, the setting unit 53 sets the current value of the control current to a current value I21, and when the laundry amount is a second laundry amount greater than the first laundry amount, the setting unit 53 sets the current value of the control current to a current value I11 greater than the current value I21.

[0073] Table 1 shows an example of the relationship between the laundry amount and the control current. As shown in Table 1, the control means 20 controls with a small control current when the laundry amount value is small, and controls with a large control current when the laundry amount value is large.

[0074] [Table 1]

[0075] In this case, the setting unit 53 may set the current values ​​I11 and I21 of the control current at the end of the open-loop control period to correspond to the current value of the stable current in feedback control. The characteristic K1 when the laundry load is large becomes stable after time T131, and the characteristic K2 when the laundry load is small becomes stable after time T132. The current values ​​of the stable current after times T131 and T132 vary depending on the laundry load and can be estimated by the control unit 51. As shown in FIG. 10, the setting unit 53 may set the current value I11 equal to the current value of the stable current after time T131 of the characteristic K1, and may set the current value I21 equal to the current value of the stable current after time T132 of the characteristic K2.

[0076] Table 2 shows an example of the relationship between the laundry weight, the control current, and the stable current. As shown in Table 2, the current value of the stable current varies depending on the laundry weight, and the control means 20 controls with a control current equal to the current value of the stable current.

[0077] [Table 2]

[0078] Furthermore, the setting unit 53 may set the current values ​​I11 and I21 of the control current at the end of the open-loop control period to correspond to the current value of the current supplied from the inverter circuit 17 to the motor 4 at the start of feedback control. For example, the setting unit 53 may set the current values ​​I11 and I21 of the control current at the end of the open-loop control period to be equal to the current value of the control current supplied from the inverter circuit 17 to the motor 4 at the start of feedback control.

[0079] Furthermore, the setting unit 53 sets the current values ​​I12, I22 of the control current at the start of the open-loop control period (time T11) to be greater than the current values ​​I11, I21 of the control current at the end of the open-loop control period. The setting unit 53 sets the current values ​​I12, I22 to, for example, twice the current values ​​I11, I21, and continuously reduces the current values ​​of the control current from the current values ​​I12, I22 to the current values ​​I11, I21 from time T11 to time T12. Note that the current values ​​I12, I22 are not limited to twice the current values ​​I11, I21, and may be set to three or more times the current values ​​I11, I21.

[0080] Table 3 shows an example of the relationship between the laundry weight and the control current at the start and end of open-loop control. As shown in Table 3, the current value of the control current at the end of open-loop control varies depending on the laundry weight, and the current value of the control current at the start of open-loop control is larger than the current value of the control current at the end of open-loop control. At the start of open-loop control, the control means 20 controls with a control current that is larger than the control current at the end of open-loop control.

[0081] [Table 3]

[0082] Furthermore, the setting unit 53 sets the current value of the control current during the positioning control period based on the current value of the control current during open-loop control. As shown in Fig. 10, the setting unit 53 may set the current value of the control current during the positioning control period to be equal to the current values ​​I11 and I21 of the control current at the start of the open-loop control.

[0083] Next, in step SP03, the control unit 51 executes positioning control using the control current whose current value was set in step SP02. At time T10, the control unit 51 fixes the phase of the control current to, for example, 270° and the current value I12 of the control current to, for example, 1.0 A, thereby applying a DC voltage with a constant phase, and thereby converging the rotor direction of the motor 4 to 270°. Furthermore, the control unit 51 fixes the phase of the control current to, for example, 0° and the current value I12 of the control current to, for example, 1.0 A, thereby converging the rotor direction of the motor 4 to 0° by applying a DC voltage with a constant phase.

[0084] Next, in step SP04, control unit 51 executes open-loop control of washing / spin-drying tub 2 using the control current whose current value was set in step SP02.

[0085] When the rotation speed of washing and spin-drying tub 2 increases to the predetermined value (35 rpm) or higher through open-loop control, control unit 51 then executes feedback control of washing and spin-drying tub 2 in step SP05.

[0086] Next, in step SP06, control unit 51 determines whether or not to end the washing process based on the elapsed time since the start of the washing process, etc.

[0087] If the washing step is not to be ended (step SP06: NO), then in step SP07, a correction process for the current value of the control current is executed.

[0088] 11 is a simplified timing chart showing the rotation speed of washing / spinning tub 2 and the waveform of the control current for two consecutive water supply rotation operations. For example, if double washing is selected in the washing process, two water supply rotation operations are included in one washing process.

[0089] Times T10 to T11 correspond to the positioning control period for the (N-1)th (N is a natural number greater than or equal to 2) water supply rotation operation, times T11 to T12 correspond to the open-loop control period for the (N-1)th water supply rotation operation, and times T12 to T14 correspond to the feedback control period for the (N-1)th water supply rotation operation. Furthermore, times T20 to T21 correspond to the positioning control period for the Nth water supply rotation operation, times T21 to T22 correspond to the open-loop control period for the Nth water supply rotation operation, and times T22 to T24 correspond to the feedback control period for the Nth water supply rotation operation.

[0090] 11, if the current value of the control current is larger than the appropriate value corresponding to the laundry amount, the rotation speed of washing and spin-drying tub 2 will greatly exceed the target value R0, as in the (N-1)th water supply rotation operation, and there is a high possibility that water will splash outside of washing and spin-drying tub 2 during the water supply rotation operation. If the current value of the control current used in the (N-1)th water supply rotation operation is used during the Nth water supply rotation operation without being reduced from the current value of the control current used in the (N-1)th water supply rotation operation, there is a risk that water will splash outside of washing and spin-drying tub 2 during the Nth water supply rotation operation.

[0091] The error calculation unit 54 calculates the error (R1-R0) between the target value R0 and the estimated value R1 of the rotation speed of the washing and spin-drying tub 2 at the transition timing (time T12) from the open-loop control period to the feedback control period of the N-1th water supply rotation operation.

[0092] The correction unit 55 corrects the current value of the control current in the Nth water supply rotation operation (the current value I13 set by the setting unit 53 based on the laundry amount) based on the error calculated by the error calculation unit 54 in the (N-1)th water supply rotation operation. The correction unit 55 corrects the current value I13, for example, by multiplying the current value I13 by the reciprocal of the ratio of the estimated value R1 to the target value R0.

[0093] As a result, in the Nth water supply rotation operation, control unit 51 uses the control current with corrected current value I13 to perform open-loop control of washing / spin-drying tub 2. Thereafter, the same process as above is repeatedly performed.

[0094] As a result of correcting the current value I13 of the control current, the error (R2-R0) between the target value R0 and the estimated value R2 in the Nth water supply rotation operation is smaller than the error (R1-R0) between the target value R0 and the estimated value R1 in the N-1th water supply rotation operation.

[0095] 10 illustrates an example in which the correction unit 55 corrects the current value I13 to be less than the current value I11 when the estimated value R1 exceeds the target value R0 (i.e., when an overshoot occurs), but the present invention is not limited to this example. The correction unit 55 may correct the current value I13 to be greater than the current value I11 when the estimated value R1 is less than the target value R0 (i.e., when an undershoot occurs).

[0096] In addition, when the error between the estimated value R2 and the target value R0 converges within a predetermined allowable range, the control unit 51 may perform open-loop control of the washing and spin-drying tub 2 using a control current of current value I13 for the water supply rotation operation from the (N+1)th onwards.

[0097] FIG. 12 is a timing chart showing, in a simplified form, the rotation speed of washing and spin-drying tub 2 and the waveform of the current value of the control current when motor 4 loses synchronism during the water supply rotation operation.

[0098] Times T10 to T11 correspond to the positioning control period for the (N-1)th (N is a natural number greater than or equal to 2) water supply rotation operation, and times T11 to T12 correspond to the open-loop control period for the (N-1)th water supply rotation operation. Furthermore, times T20 to T21 correspond to the positioning control period for the Nth water supply rotation operation, times T21 to T22 correspond to the open-loop control period for the Nth water supply rotation operation, and times T22 to T24 correspond to the feedback control period for the Nth water supply rotation operation.

[0099] If the current value I11 of the control current during the open-loop control period of the (N-1)th water supply rotation operation is significantly lower than the current value of the stable current during the feedback control period, motor 4 will step out, and in some cases, the rotation operation of washing and spin-drying tub 2 will stop. For example, if the current value I11 of the control current during the open-loop control period is smaller than the current value of the stable current during the feedback control period (an appropriate value according to the amount of laundry), motor 4 may step out.

[0100] At the timing (time T12) when the open-loop control is switched to the feedback control, the control unit 51 detects that the motor 4 has lost synchronism by detecting that the washing / spinning tub 2 is not rotating. At this time, if the current value of the control current used in the (N-1)th water supply rotation operation is used in the Nth water supply rotation operation without increasing the current value of the control current used in the (N-1)th water supply rotation operation, the motor 4 may also lose synchronism in the Nth water supply rotation operation.

[0101] When the control unit 51 detects that the motor 4 has lost synchronization, the setting unit 53 resets the current values ​​I13 and I14 to values ​​higher than the current values ​​T11 and I12 set in the water supply rotation operation that lost synchronization. The control unit 51 then executes the water supply rotation operation again using the control currents I13 and I14 reset by the setting unit 53.

[0102] As described above, in this embodiment, the washing machine comprises washing and spin-drying tub 2 in which laundry is stored, water supply means including water supply valve 14 for supplying water to washing and spin-drying tub 2, motor 4 for rotating washing and spin-drying tub 2, inverter circuit 17 which is a motor drive circuit for driving motor 4, and control means 20 which is a control device.Control means 20 performs a water supply rotation operation which is an operation for supplying water to washing and spin-drying tub 2 while rotating washing and spin-drying tub 2, and control means 20 comprises a fabric amount detection unit 52 which detects the fabric amount, which is the amount of laundry stored in washing and spin-drying tub 2, and a setting unit 53 which sets the current value of the control current supplied from inverter circuit 17 to motor 4 during the water supply rotation operation based on the fabric amount detected by fabric amount detection unit 52.

[0103] This allows the current value of the control current to be appropriately set based on the laundry amount detected by laundry amount detection unit 52. As a result, it is possible to prevent water from splashing outside washing / spinning tub 2 during the water supply rotation operation. In addition, since control can be stabilized, it is possible to prevent motor 4 from losing synchronization.

[0104] Furthermore, as in this embodiment, the control of the water supply rotation operation by the control means 20 includes open-loop control that does not feed back an estimated value of the rotation speed of the motor 4 in a speed range where the rotation speed of the washing and spin-drying tub 2 is below a predetermined value, and feedback control that feeds back an estimated value of the rotation speed of the motor 4 in a speed range where the rotation speed of the washing and spin-drying tub 2 is equal to or greater than a predetermined value, and the control current is preferably a current supplied from the inverter circuit 17 to the motor 4 in the open-loop control.

[0105] This allows the current values ​​I11 and I21 of the control currents in the open-loop control of a washing machine that controls motor 4 using a sensorless method to be appropriately set based on the laundry amount detected by laundry amount detection unit 52. As a result, splashing of water outside washing / spin tub 2 during the water supply rotation operation can be suppressed.

[0106] Furthermore, as in this embodiment, the setting unit 53 sets the current value of the control current to a first current value when the laundry amount is a first laundry amount, and sets the current value of the control current to a second current value that is greater than the first current value when the laundry amount is a second laundry amount that is greater than the first laundry amount.

[0107] This allows the current value I21 of the control current to be set small when the laundry amount is small, and the current value I11 of the control current to be set large when the laundry amount is large. As a result, by controlling the current values ​​I11 and I21 of the control current based on the laundry amount detected by laundry amount detection unit 52, it is possible to prevent water from splashing outside of washing and spin tub 2 during the water supply rotation operation. Furthermore, since control can be stabilized, it is possible to prevent motor 4 from losing synchronization.

[0108] Furthermore, as in this embodiment, the current value of the control current may correspond to the current value of the stable current in feedback control, which is defined according to the amount of laundry.

[0109] This makes it possible to suppress current fluctuations after feedback control, thereby achieving stable control.

[0110] Furthermore, as in this embodiment, the current value of the control current may correspond to the current value of the current supplied from the inverter circuit 17 to the motor 4 at the start of feedback control.

[0111] This makes it possible to suppress current fluctuations when switching from open-loop control to feedback control, thereby enabling a smooth transition from open-loop control to feedback control and achieving stable control.

[0112] Furthermore, as in this embodiment, the setting unit 53 may set the current value of the control current at the start of the open-loop control to be greater than the current value of the control current at the end of the open-loop control.

[0113] As a result, by setting the current values ​​I12 and I22 of the control current at the start of open-loop control to be larger than the current values ​​I11 and I21 of the control current at the end of open-loop control, it is possible to reliably start the rotation of the motor 4, which requires torque, and to stabilize the open-loop control.

[0114] Furthermore, as in this embodiment, the control of the water supply rotation operation by the control means 20 further includes positioning control for positioning the direction of the rotor of the motor before the open loop control, and the setting unit 53 further sets the current value of the control current in the positioning control based on the current value of the control current in the open loop control.

[0115] This allows the current values ​​I12 and I22 of the control currents in positioning control to be set appropriately, resulting in stable start of rotation of the motor 4 in open-loop control. Also, the current values ​​I12 and I22 of the control currents can be set to the same value at the end of positioning control and the start of open-loop control, thereby enabling a smooth transition from positioning control to open-loop control.

[0116] Furthermore, as in this embodiment, when the control means 20 detects out-of-step of the motor 4 at the timing of transition from open loop control to feedback control, it is preferable to re-execute the water supply rotation operation using a control current having a higher current value than the control current value set by the setting unit 53 in the out-of-step water supply rotation operation.

[0117] This makes it possible to suppress current fluctuations after feedback control and achieve stabilization of control, thereby preventing further loss of synchronization.

[0118] Furthermore, as in this embodiment, the control means 20 executes the water supply rotation operation multiple times, and the control means 20 may further include an error calculation unit 54 that calculates the error between the target value and the estimated value of the rotation speed of the washing and spin-drying tub 2 at the timing of transition from open-loop control to feedback control, and a correction unit 55 that corrects the current value of the control current set by the setting unit 53 in the Nth water supply rotation operation (N is a natural number greater than or equal to 2) based on the error calculated by the error calculation unit 54 in the N-1th water supply rotation operation.

[0119] This allows the current value I13 of the control current in the N-th water supply rotation operation to be appropriately corrected based on the error in the (N-1)th water supply rotation operation, thereby more effectively suppressing water from splashing outside washing and spin tub 2 during the water supply rotation operation.

[0120] It should be noted that the above-described embodiments are intended to illustrate the technology of the present disclosure, and various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents. [Industrial Applicability]

[0121] The present disclosure is widely applicable to washing machines equipped with a washing tub. [Explanation of symbols]

[0122] 2 Washing and spin tub (washing tub) 4 motors 17 Inverter circuit (motor drive circuit) 20 Control means (control device) 52 Cloth amount detection unit 53 Setting section 54 Error calculation section 55 Correction section

Claims

1. a washing tub for storing laundry; a water supply means for supplying water to the washing tub; a motor for rotating the washing tub; a motor drive circuit that drives the motor; a control device; Equipped with the control device executes a water supply rotation operation, which is an operation of supplying water to the washing tub while rotating the washing tub, The control device a laundry amount detection unit that detects the amount of laundry contained in the washing tub; a setting unit that sets a current value of a control current supplied from the motor drive circuit to the motor during the water supply rotation operation based on the laundry amount detected by the laundry amount detection unit; having washing machine.

2. The control of the water supply rotation operation by the control device is open-loop control that does not feed back the estimated value of the rotation speed of the motor in a speed range where the rotation speed of the washing tub is less than a predetermined value; a feedback control for feeding back an estimated value of the rotation speed of the motor when the rotation speed of the washing tub is in a speed range equal to or higher than the predetermined value; and the control current is a current supplied from the motor drive circuit to the motor in the open loop control; The washing machine according to claim 1.

3. The setting unit When the laundry amount is a first laundry amount, the current value of the control current is set to a first current value; When the laundry amount is a second laundry amount that is greater than the first laundry amount, the current value of the control current is set to a second current value that is greater than the first current value. The washing machine according to claim 2.

4. the current value of the control current corresponds to the current value of a stable current in the feedback control, which is determined in accordance with the laundry weight. The washing machine according to claim 2.

5. the current value of the control current corresponds to the current value of the current supplied from the motor drive circuit to the motor at the start of the feedback control; The washing machine according to claim 2.

6. the setting unit sets a current value of the control current at a start of the open-loop control to be greater than a current value of the control current at a termination of the open-loop control. The washing machine according to claim 2.

7. The control of the water supply rotation operation by the control device further includes a positioning control for positioning the direction of a rotor of the motor before the open loop control, the setting unit further sets a current value of the control current in the positioning control based on a current value of the control current in the open loop control. The washing machine according to claim 2.

8. When the control device detects a step-out of the motor at the timing of transition from the open loop control to the feedback control, the control device re-executes the water supply rotation operation using a control current having a current value higher than the current value of the control current set by the setting unit in the step-out water supply rotation operation. The washing machine according to claim 2.

9. The control device executes the water supply rotation operation a plurality of times, The control device an error calculation unit that calculates an error between a target value and an estimated value of the rotation speed of the washing tub at a transition timing from the open loop control to the feedback control; a correction unit that corrects the current value of the control current set by the setting unit in an N-th (N is a natural number equal to or greater than 2) water supply rotation operation based on the error calculated by the error calculation unit in an N-1-th water supply rotation operation; further comprising The washing machine according to claim 2.

10. A method for controlling a washing machine including a washing tub for accommodating laundry, a water supply unit for supplying water to the washing tub, a motor for rotating the washing tub, and a motor drive circuit for driving the motor, The control device A water supply rotation operation is performed to supply water to the washing tub while rotating the washing tub; Detecting the amount of laundry contained in the washing tub; a current value of a control current supplied from the motor drive circuit to the motor during the water supply rotation operation is set based on the detected laundry weight; How to control a washing machine.

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