JP2022126029A - washing machine - Google Patents

Abstract

To provide a washing machine which can shorten an operation time.SOLUTION: A washing machine includes: a washing and dewatering tub; an agitation vane rotatably disposed in the washing and dewatering tub; an electric motor having a permanent magnet and a coil, and for rotationally driving the washing and dewatering tub and the agitation vane; a power supply circuit for supplying an electric current to the electric motor; a current detection part for detecting the current in the electric motor; and a control part for executing acceleration control, constant speed control, and deceleration control of the electric motor. The deceleration control includes pause control. The control part estimates the speed of the electric motor by performing PWM control of the electric motor so that the electric current of the torque component becomes constant, during the pause control.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to washing machines.

Patent Document 1 discloses voltage detection means for generating a detection voltage corresponding to terminal voltages of multi-phase stator windings of a brushless motor, reference voltage generation means for generating a reference voltage, and comparison between the detection voltage and the reference voltage. control means for detecting the rotational position of the rotor of the brushless motor based on the comparison result information signal output as a result, and for generating an energization signal for the stator windings according to the rotational position; A washing machine is disclosed that uses, as a power source, a brushless motor whose operation is controlled by a brushless motor controller including output means for energizing a stator winding.

JP-A-2005-6500

The present disclosure provides a washing machine capable of shortening operating time.

The washing machine according to the present disclosure has a washing/drying tub, an agitating blade rotatably disposed in the washing/drying tub, and a permanent magnet and a winding, and an electric motor that rotationally drives the washing/drying tub and the agitating blade. , a power supply circuit that supplies current to the electric motor, a current detection unit that detects the electric current of the electric motor, and a control unit that executes acceleration control, constant speed control, and deceleration control of the electric motor. Deceleration control includes pause control. The control unit estimates the speed of the electric motor by PWM-controlling the electric motor so that the current of the torque component is constant during the pause control period.

The washing machine according to the present disclosure can estimate the timing at which the motor 4 stops, and can determine the timing to shift to the stroke after the motor 4 stops. Therefore, driving time can be shortened.

Principal part cross-sectional view of the washing machine according to Embodiment 1 Block diagram of the drive system of the motor of the washing machine Equivalent circuit diagram of the motor of the washing machine Control block diagram when estimating the phase of the motor of the same washing machine Detailed block diagram of the speed phase estimation means of the motor of the washing machine (a) A vector diagram in which the estimated coordinates are delayed when estimating the phase of the motor of the washing machine, (b) A vector diagram in which the estimated coordinates are advanced when estimating the phase of the motor of the washing machine. Flowchart of deceleration control of the same washing machine Flowchart of motor stop control processing of the washing machine Flowchart of motor current control processing of the same washing machine Flowchart of deceleration control with delay time for washing machine according to Embodiment 2

(Knowledge, etc. on which this disclosure is based)
At the time the inventors came to the present disclosure, washing machines, for example, do not output voltage to the terminals of the multi-phase stator windings of a brushless motor during coasting. In other words, the rotational position of the rotor of the brushless motor cannot be detected based on the comparing means for comparing the voltage with the reference voltage and outputting the comparison result information signal. For this reason, when it is not possible to determine that the motor has stopped and it is necessary to shift the process after stopping the motor, the problem that it is not possible to determine that the motor has stopped and shift to the optimum timing is solved. The inventors have discovered and come to constitute the subject of this disclosure in order to solve the problem.

Accordingly, the present disclosure provides a washing machine capable of estimating speed during sleep control.

Hereinafter, embodiments will be described in detail with reference to the drawings. However, more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters or redundant descriptions of substantially the same configurations may be omitted.

It should be noted that the accompanying drawings and the following description are provided to allow those skilled in the art to fully understand the present disclosure and are not intended to limit the claimed subject matter thereby.

(Embodiment 1)
Embodiment 1 will be described below with reference to FIGS. 1 to 9. FIG.

[1-1. Constitution]
[1-1-1. Configuration of washing machine]
In FIG. 1 , washing machine 100 includes washing machine outer frame 9 .

A water receiving tub 3 is arranged inside the outer frame 9 of the washing machine, and a washing and dehydrating tub 2 is arranged inside the water receiving tub 3 so as to be rotatable for dehydration. At the bottom of the washing and dehydrating tub 2, a pulsator 1 for agitating clothes is arranged so as to be left and right rotatable. A motor 4 is fixed to the outer bottom of the water receiving tank 3 . The rotation of the motor 4 rotates and brakes the pulsator 1 and the washing/dehydrating tub 2 via the motor pulley 31 , the belt 5 , the impeller pulley 32 , and the deceleration mechanism/clutch 6 .

A reduction ratio (for example, 1/4) is provided between the motor pulley 31 and the impeller pulley 32, and when the motor pulley 31 attached to the motor shaft (not shown) of the motor 4 rotates four times, the reduction mechanism/clutch 6 is turned. The impeller pulley 32 (or the washing and dewatering tub 2) attached to the impeller shaft (not shown) rotates once.

Similarly, the speed reduction mechanism/clutch 6 between the impeller pulley 32 and the pulsator 1 has a speed reduction ratio (for example, 1/6). not shown) are in a relationship of one rotation. The brake can be controlled by applying a reverse torque to the motor 4, or by operating the geared motor 7 and bringing the brake belt 8 into contact with the rotating part to mechanically brake the washing and dehydrating tub 2. .

A panel portion 10 is arranged above the outer frame 9 of the washing machine. A lid 11 is configured to be openable and closable on the upper surface of the panel section 10 . A control device 13 is arranged in front and inside of the panel portion 10 .

The control device 13 has control means 20 comprising a microcomputer. The control means 20 controls the operations of the motor 4, the water supply valve 14, the drain valve 15, etc., and sequentially controls a series of processes such as washing, rinsing, and dehydration. The control means 20 executes acceleration control, constant speed control, and deceleration control of the motor 4 . The control means 20 controls the display means 12 consisting of light-emitting elements such as LEDs and LCDs based on information from input setting means (not shown) that allows the user to set a desired washing course, start operation, pause operation, etc. , to notify the user by displaying the process progress and various information. When operation start is set by the input setting means, the operations of the geared motor 7, the water supply valve 14 and the drain valve 15 are controlled according to data from the water level detection means (not shown) and the like to perform the washing operation.

[1-1-2. Configuration of Motor and Peripherals]
FIG. 2 is a block diagram of the drive system of the motor of the washing machine according to Embodiment 1. FIG.

The AC power supply applies AC power to the rectifier circuit 16 , the rectifier circuit 16 is composed of a voltage doubler rectifier circuit, and the inverter circuit 17 is applied with the doubled DC voltage. The inverter circuit 17 consists of a three-phase full-bridge inverter circuit consisting of six power switching semiconductors and anti-parallel diodes, and normally incorporates insulated gate bipolar transistors (IGBTs), anti-parallel diodes, their drive circuits and protection circuits. It is composed of an intelligent power module (hereinafter referred to as IPM). The motor 4 is connected to the output terminal of the inverter circuit 17 and driven.

The current detection means 18 connects a shunt resistor between the negative voltage terminal of the inverter circuit 17 and the negative voltage terminal of the rectifier circuit 16. Based on the input current of the inverter circuit 17 calculated from the voltage across the shunt resistor, the motor 4 phase currents Iu, Iv and Iw are detected. Since the DC voltage applied to the inverter circuit 17 may be superimposed by the regenerative energy generated by the rotation of the motor in addition to the input from the AC power supply, it is always detected.

The PWM control means 19 controls PWM signals for switching the IGBTs of the inverter circuit 17 according to the applied voltages Vus, Vvs, and Vws from the control means 20, and drives the motor 4 with the output voltages Vu, Vv, and Vw of the inverter circuit. do.

3 is an equivalent circuit diagram of the motor of the washing machine according to Embodiment 1. FIG.

Here, for the sake of simplification of explanation, a two-pole configuration is used in which one rotation of the mechanical angle corresponds to one rotation of the electrical angle. When the number of poles changes to 4 poles, 8 poles, . The motor 4 is a three-phase synchronous motor, and is composed of an equivalent circuit having three-phase windings 4a, 4b, and 4c of U, V, and W, and a permanent magnet 4d, which is a rotor that rotates around the rotation axis. . In this equivalent circuit, the axis passing through the permanent magnet on the N pole side in the positive direction is defined as the d-axis (direct-axis), and the axis orthogonal thereto is defined as the q-axis (quadrature-axis). When defined in this way, it is the magnetic field in the q-axis direction that mainly controls the torque of the motor. Also, the phase (electrical angle) is the rotation angle θr between the axis passing through the U-phase winding and the d-axis. All phases described below are electrical angles. Let Ld be the inductance of the winding when a voltage is applied so as to generate a magnetic field in the d-axis direction, and Lq be the inductance in the q-axis direction.

The embedded magnet type three-phase synchronous motor has a relationship of Ld<Lq. Since the control means 20, which will be described later, cannot accurately detect the position of the rotor at first, it assumes that the phase is θc as shown in FIG. is occurring. That is, the axes on which the microcomputer performs control assuming the phase θc are the γ-axis (estimated d-axis) and δ-axis (estimated q-axis) with respect to the actual d-axis and q-axis of the motor. Hereafter, the current component corresponding to the torque in the microcomputer is the δ-axis current Iδ, the current component corresponding to the magnetic flux in the microcomputer is the γ-axis current Iγ, the voltage component corresponding to the torque in the microcomputer is the command δ-axis voltage Vδs, the microcomputer internal A command γ-axis voltage Vγs is defined as a voltage component corresponding to the magnetic flux of .

[1-1-3. Configuration of Control Means]
FIG. 4 is a control block diagram when estimating the phase of the motor of the washing machine according to the first embodiment.

The control means 20 includes a microcomputer (microcomputer), an inverter control timer (timer) built in the microcomputer, an A/D converter, a memory circuit, a speed phase estimation means 21, a three-phase two-phase converter 22, an Iδ error amplifier 23, It comprises an Iγ error amplifier 24, a two-to-three phase converter 25, a speed error amplifier 26, a field weakening setting means 27, etc., and performs inverter control as follows.

Details of the velocity phase estimation means 21 will be described later. The velocity phase estimator 21 inputs the δ-axis current Iδ, γ-axis current Iγ, and command γ-axis voltage Vγs, and outputs an estimated velocity ω (electrical angular velocity) and an estimated phase θ. All velocities described below are electrical angular velocities.

The three-to-two-phase converter 22 converts the electrical angle θ, the phase currents Iu, Iv, and Iw, and the sinusoidal data (sin, cos data) necessary for converting from the stationary coordinate system to the rotating coordinate system into the γ-axis current. Iγ and δ-axis current Iδ are calculated as shown in Equation (1).

An Iδ error amplifier 23 receives an error ΔIδ with respect to the command value Iδs of the δ-axis current from the δ-axis current command Iδs obtained by the speed error amplifier 26 and the δ-axis current Iδ obtained by the three-to-two-phase converter 22. and the sum of the integral components, the command .delta.-axis voltage V.delta.s is output.

Similarly, the Iγ error amplifier 24 inputs the error ΔIγ with respect to the command value Iγ of the γ-axis current from the γ-axis current command Iγs obtained by the field-weakening setting means 27 and the γ-axis current Iγ obtained by the three-to-two-phase converter 22. and outputs the command γ-axis voltage Vγs as the sum of the proportional component and the integral component.

It is called vector control because it is decomposed into the δ-axis current Iδ and the γ-axis current Iγ and controlled independently.

The two-to-three phase converter 25 receives the estimated phase θ, the command δ-axis voltage Vδs, the command γ-axis voltage Vγs, and sine wave data (sin, cos data) necessary for inverse transformation from the rotating coordinate system to the stationary coordinate system. , applied voltages Vus, Vvs, and Vws, which are sinusoidal commands, are calculated as shown in Equation (2).

A speed error amplifier 26 receives the error Δω with respect to the speed command ωs from the speed command ωs and the estimated speed ω calculated by the speed phase estimating means 21, and outputs a δ-axis current command Iδs that is the sum of the proportional component and the integral component.

The field-weakening setting means 27 calculates a negative direction γ-axis current command Iγs from the estimated speed ω calculated by the speed phase estimating means 21 and the DC voltage Vdc input to the inverter circuit, and performs flux-weakening control.

FIG. 5 is a detailed block diagram of the washing machine motor speed phase estimating means according to the first embodiment.

The speed phase estimating means 21 calculates an estimated phase θ using the resistance value Ra and the inductance value L of the windings 4 a , 4 b , 4 c which are parameters of the motor 4 . The velocity phase estimator 21 comprises 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 from the inductance value L, the resistance value Ra, the δ-axis current Iδ, the γ-axis current Iγ, the command γ-axis voltage Vγs, and the estimated speed ω as shown in Equation 3. .

With the γ-axis induced voltage command Veγs=0, the error ΔVeγ with respect to the γ-axis induced voltage command Veγs is input to the γ-axis induced voltage error amplifier 29 .

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 the value calculated from the proportional gain Kθ, performs time integration with an integrator, and outputs an estimated phase θ. do.

However, the γ-axis induced voltage calculator 28 is not necessarily limited to using Equation 3, and may be calculated using Equation 4 with a time differential term added.

As for the inductance value L in each of the above formulas, the same L value can be used as long as the motor 4 has the characteristic of Ld=Lq.
q).

FIG. 6(a) shows a vector of a state in which the estimated coordinates during the phase estimation of the motor of the washing machine in Embodiment 1 are delayed (the γδ coordinates (estimated dq coordinates) are slightly behind the dq coordinates of the motor 4). FIG. 6(b) is a vector diagram of the state in which the estimated coordinates during the phase estimation of the motor of the washing machine are advanced (the γδ coordinates (estimated dq coordinates) are slightly advanced with respect to the dq coordinates of the motor 4). be.

In the vector diagram, the γ-axis induced voltage error ΔVeγ is the γ-axis component of the estimated induced voltage vector Ve (=ω×Ψa) obtained by subtracting the drop of the current flowing through Ra and ωL from the input voltage Va of the motor 4. Since the induced voltage vector Ve is always on the q-axis, the q-axis coincides with the δ-axis when the estimated phase error Δθ (the state in which the γδ coordinate comes counterclockwise to the dq coordinate is positive) is 0. do. In FIG. 6A, the estimated phase error Δθ is negative (Δθ<0), and in FIG. 6B, the estimated phase error Δθ is positive (Δθ>0).

In the case of FIG. 6(a), the γ-axis induced voltage error amplifier 29 increases the estimated speed ω and advances the estimated phase θ, and in the case of FIG. By delaying, feedback control is performed so that the γ-axis induced voltage error ΔVeγ and the estimated phase error Δθ become zero. In this way, phase estimation is based on the assumption that the motor is rotating with induced voltage Ve. Therefore, phase estimation is not stable in the low-speed region when the induced voltage is low, such as when starting or stopping. Open-loop control is used without

[1-2. motion]
In the above configuration, deceleration control of the motor 4 according to the first embodiment will be described with reference to FIGS. 7 to 9. FIG.

[1-2-1. Deceleration control]
7 is a flowchart of deceleration control of the washing machine according to Embodiment 1. FIG.

Deceleration control is started from step 500 . At step 501, the process proceeds to a motor stop control processing routine (details of which will be described later). At step 502, it is checked whether the motor rotation speed N is smaller than the minimum detection rotation speed N_min (for example, 10 r/min) as motor stop determination processing. do. If equal or greater (NO), go to step 501 .

[1-2-2. Pause Control Processing Routine]
FIG. 8 is a flowchart of motor stop control processing of the washing machine according to Embodiment 1. FIG. The motor halt control process is started from step 700 . At step 701, a fixed value is substituted for the command .delta.-axis current I.delta.s. At step 702, the current control timer Te_tm is cleared to zero. At step 703, the process proceeds to a current control processing routine (details of which will be described later). At step 704, the current control processing time (for example, 0.1 ms) is added to the current control timer Te_tm. At step 705, it is checked whether the current control timer Te_tm is greater than the current control cycle Te_cycle. At step 706, the motor halt control process is terminated.

The fixed value to be substituted for the command .delta.-axis current I.delta.s at step 701 will be described below. As a fixed value for the command δ-axis current Iδs, there are a method of substituting 0, a method of substituting a negative fixed value, and a method of substituting a minute positive fixed value. The method of substituting 0 for the command δ-axis current Iδs is used to prevent torque from being generated. The method of substituting a negative fixed value for the command .delta.-axis current I.delta.s is used to generate braking torque to such an extent that regenerative voltage does not pose a problem and to shorten the braking time. The method of substituting a minute positive fixed value for the command δ-axis current Iδs is used to prevent excessive braking torque from being applied to the inertial rotation by the method of using a negative fixed value. As an example of the purpose of using a positive fixed value, in the case of a method of tightening a spring in the direction of rotation of the washing/drying tub 2 and switching the clutch to the side of the washing/drying tub 2, what is the rotation direction of the washing/drying tub 2? When the brake torque is applied in the opposite direction and the spring is loosened, it may be possible to prevent the clutch on the side of the washing and dehydrating tub 2 from being released. The method of substituting 0 for the command δ-axis current Iδs, the method of substituting a negative fixed value, and the method of substituting a small positive fixed value are easy-to-use methods depending on the amount of laundry and the configuration of the washing machine. can be selected.

[1-2-3. Current control processing routine]
9 is a flowchart of motor current control processing of the washing machine according to Embodiment 1. FIG.

Motor current control processing is started from step 800 . At step 801, the phase currents Iu, Iv, and Iw are detected by the current detection means 18, and at step 802, the three-to-two-phase converter 22 calculates the δ-axis current Iδ as shown in Equation (1). At step 803, it is checked whether the δ-axis current Iδ is greater than the command δ-axis current Iδs. If the δ-axis current Iδ is equal to the command δ-axis current Iδs or smaller than the command δ-axis current Iδs (NO) at step 803, the process proceeds to step 805, where the command δ-axis voltage Vδs is increased.

When the Iδ error amplifier 23 sets the command δ-axis voltage Vδs in steps 803 to 805, the variable elements are large and the control is not stable.

Thereafter, similarly to the δ-axis, the voltage of the γ-axis is calculated in steps 806-809. At step 806, the γ-axis current Iγ is calculated by the three-phase to two-phase converter 22 as shown in Equation (1). At step 807, it is checked whether the γ-axis current Iγ is greater than the command γ-axis current Iγs. At step 808, the command γ-axis voltage Vγs is decreased. At step 811, the command γ-axis voltage Vγs is increased. When the command γ-axis voltage Vγs is set by the Iγ error amplifier 24 in steps 807 to 809, the variable elements are large and the control is not stable.

At step 810, the applied voltages Vus, Vvs, and Vws are calculated by the two-to-three-phase converter 25 as shown in Equation (2). At step 811 , a voltage is applied to the motor 4 via the PWM control means 19 and the inverter circuit 17 . At step 812, the motor current control process ends.

[1-3. effects, etc.]
As described above, in the present embodiment, washing machine 100 includes washing/drying tub 2 , pulsator 1 , motor 4 , inverter circuit 17 , current detection means 18 , and control device 13 . A pulsator 1 is rotatably arranged in a washing and dewatering tub 2 . The motor 4 has a permanent magnet 4d, windings 4a, 4b, and 4c, and drives the washing/dehydration tub 2 and the pulsator 1 to rotate. The inverter circuit 17 supplies current to the motor 4 . A current detection means 18 detects the current of the motor 4 . The control device 13 executes acceleration control, constant speed control and deceleration control of the motor 4 . The deceleration control includes pause control, and the control device 13 estimates the estimated speed ω of the motor 4 by PWM-controlling the motor 4 so that the δ-axis current Iδ remains constant during the period of pause control.

As a result, the timing at which the motor 4 stops can be estimated, and the timing for shifting to the stroke after the motor 4 has stopped can be determined. Therefore, driving time can be shortened.

As in the present embodiment, the control device 13 may PWM-control the motor 4 so that the δ-axis current Iδ becomes 0 during the pause control period.

This prevents the motor 4 from generating torque.

As in the present embodiment, the control device 13 compares the rotation speed N of the motor 4 calculated from the estimated speed ω with the minimum detected rotation speed N_min during the pause control period. If the rotation speed is smaller than N_min, the deceleration control may be terminated.

As a result, the control device 13 can determine the timing of shifting to the stroke after the motor 4 stops during deceleration control.

(Embodiment 2)
Embodiment 2 will be described below with reference to FIG. The second embodiment differs from the first embodiment in deceleration control of the motor 4 .

[2-1. motion]
[2-1-1. Deceleration control]
FIG. 10 is a flow chart of deceleration control of the washing machine according to the second embodiment.

Deceleration control is started from step 900 . At step 901, the process proceeds to a motor stop control processing routine. At step 902, it is checked whether the motor rotation speed N is smaller than the minimum detected rotation speed N_min (for example, 10 r/min) as motor stop determination processing. If equal or greater (NO), go to step 901 . At step 903, the time measuring counter tm is added, and at step 904, the time measuring counter tm is compared with the delay time delay_tm. At step 904, if the time measurement counter tm is greater than the delay time delay_tm (YES), the deceleration control is terminated. At step 904 , if the time measurement counter tm is equal to or smaller than the delay time delay_tm (NO), the process proceeds to step 903 . It should be noted that in steps 903 and 904, the motor 4 is inertially rotated without being controlled to stop.

[2-2. effects, etc.]
As described above, in the present embodiment, the control means 20 ends the deceleration control after the delay time delay_tm has elapsed from the time when the rotational speed N of the motor 4 becomes smaller than the minimum detectable rotational speed.

As a result, it is possible to determine whether the motor 4 is stopped with higher accuracy.

(Other embodiments)
As described above, Embodiments 1 and 2 have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to embodiments with modifications, replacements, additions, omissions, and the like. Also, it is possible to combine the constituent elements described in the first and second embodiments to form a new embodiment.

Therefore, other embodiments will be exemplified below.

In Embodiments 1 and 2, the minimum detectable rotation speed N_min is set to a predetermined value (for example, 10 r/min), but it may be set to the rotation speed N at the time when the variation in the estimated phase θ becomes larger than the predetermined value. This is because the input voltage Va of the motor 4 becomes smaller near the minimum detectable rotation speed N_min, and the γ-axis induced voltage error ΔVeγ becomes smaller, so that the γ-axis induced voltage error ΔVeγ varies in other elements. , and the estimated phase .theta.

As a result, the control device 13 can reduce the influence of the amount of clothes in the washing and dehydrating tub 2 and perform deceleration control of the motor 4 .

In Embodiments 1 and 2, the belt 5 connects the motor pulley 31 and the impeller pulley 32, and the reduction mechanism/clutch 6 couples the pulsator 1 or the washing/spin-drying tub 2 to the pulsator type vertical washing machine as an example. As described above, a direct drive type washing machine in which the washing/drying tub and the motor are coaxial may be used, or an agitator type vertical type washing machine may be used.

INDUSTRIAL APPLICABILITY The present disclosure is applicable to vertical washing machines capable of shortening operating time. Specifically, the present disclosure is applicable to pulsator-type vertical washing machines and agitator-type vertical washing machines.

1 pulsator (stirring blade)
2 washing and dehydrating tank 3 water receiving tank 4 motor (electric motor)
4a winding 4b winding 4c winding 4d permanent magnet (rotor)
5 belt (transmission mechanism)
6 Reduction mechanism and clutch (transmission mechanism)
7 geared motor 8 brake belt 9 washing machine outer frame 10 panel section 11 lid 12 display means 13 control device (control section)
14 water supply valve 15 drain valve 16 rectifier circuit 17 inverter circuit (power supply circuit)
18 current detection means 19 PWM control means 20 control means 21 speed phase estimation means 22 three-phase two-phase converter 23 Iδ error amplifier 24 Iγ error amplifier 25 two-phase three-phase converter 26 speed error amplifier 27 field weakening setting means 28 γ Axis induced voltage calculator 29 γ-axis induced voltage error amplifier 31 Motor pulley (transmission mechanism)
32 impeller pulley (transmission mechanism)

Claims (5)

a washing and dewatering tank,
a stirring blade rotatably disposed in the washing and dewatering tub;
an electric motor having a permanent magnet and a winding, and rotatingly driving the washing and dewatering tank and the stirring blade;
a power supply circuit that supplies current to the electric motor;
a current detection unit that detects the current of the electric motor;
a control unit that executes acceleration control, constant speed control and deceleration control of the electric motor;
with
the deceleration control includes pause control;
The control unit estimates the speed of the electric motor by PWM-controlling the electric motor so that the current of the torque component is constant during the period of the pause control.
washing machine. The control unit PWM-controls the electric motor so that the current of the torque component becomes 0 during the period of the pause control.
The washing machine according to claim 1. The control unit compares the rotation speed of the electric motor calculated from the speed with a minimum detectable rotation speed during the period of the stop control, and if the rotation speed is smaller than the minimum detectable rotation speed, the deceleration is performed. to end control,
The washing machine according to claim 1 or 2. The control unit terminates the deceleration control after a predetermined time has passed since the number of revolutions of the electric motor became smaller than the minimum detectable number of revolutions.
The washing machine according to claim 3. The minimum detectable rotation speed is the rotation speed at which variation in the rotation speed of the electric motor exceeds a predetermined value.
The washing machine according to claim 3 or 4.

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