JP7522964B2 - washing machine - Google Patents

Description

This disclosure relates to a washing machine.

Patent document 1 discloses a washing machine that uses as its power source a brushless motor whose operation is controlled by a brushless motor control device that includes: voltage detection means for generating a detection voltage according to the terminal voltage of the stator windings of multiple phases of the brushless motor; reference voltage generation means for generating a reference voltage; control means for detecting the rotational position of the rotor of the brushless motor based on a comparison result information signal output by comparing the detection voltage with the reference voltage and generating an energization signal for the stator windings according to this rotational position; and output means for energizing the stator windings based on this energization signal.

JP 2005-6500 A

This disclosure provides a washing machine that can shorten the operation time.

The washing machine according to the present disclosure includes a washing/spin-drying tub, an agitator blade rotatably disposed in the washing/spin-drying tub, an electric motor having a permanent magnet and a winding for driving the washing/spin-drying tub and the agitator to rotate, a power supply circuit for supplying current to the electric motor, a current detection unit for detecting the current of the electric motor, and a control unit for controlling the electric motor based on an estimated speed and an estimated phase of the electric motor .
The motor is subjected to acceleration control, constant speed control, and deceleration control including pause control, and during the pause control period, the motor is PWM controlled so that the current of the torque component becomes zero to estimate the estimated speed of the motor , the rotation speed of the motor is calculated from the estimated speed, and when the calculated rotation speed of the motor becomes smaller than a predetermined rotation speed, the deceleration control is terminated .

The washing machine disclosed herein can estimate the timing when the motor 4 will stop, and can determine the timing to transition to the next step after the motor 4 has stopped. This allows the operation time to be shortened.

1 is a cross-sectional view of a main part of a washing machine according to a first embodiment of the present invention; Block diagram of the motor drive system of the washing machine Equivalent circuit diagram of the washing machine motor Control block diagram for estimating the phase of the motor of the washing machine A detailed block diagram of the motor speed phase estimation means of the washing machine. (a) is a vector diagram showing a state in which the estimated coordinates are delayed when estimating the phase of the motor of the washing machine; (b) is a vector diagram showing a state in which the estimated coordinates are advanced when estimating the phase of the motor of the washing machine; Flowchart of deceleration control of the washing machine Flowchart of motor pause control process of the washing machine Flowchart of motor current control process of the washing machine Flowchart of deceleration control with delay time of washing machine in embodiment 2

(Knowledge and other information that forms the basis of this disclosure)
At the time when the inventors came up with the present disclosure, for example, a washing machine does not output a 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 a comparison means that compares the voltage with a reference voltage and outputs a comparison result information signal. As a result, the inventors discovered a problem that it is not possible to determine that the motor has stopped, and when it is necessary to shift a process after stopping the motor, it is not possible to determine that the motor has stopped and shift the process at the optimal timing. In order to solve this problem, the inventors have come up with the subject of the present disclosure.

Therefore, the present disclosure provides a washing machine that can estimate the speed during pause control.

Below, the embodiments will be described in detail with reference to the drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted.

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

(Embodiment 1)
Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 9. FIG.

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

A water receiving tub 3 is disposed inside the washing machine outer frame 9, and a washing/spinning tub 2 is disposed inside the water receiving tub 3 so that it can rotate freely for spin-drying. A pulsator 1 for agitating the clothes is disposed at the bottom of the washing/spinning tub 2 so that it can rotate left and right. A motor 4 is fixed to the outer bottom of the water receiving tub 3. The rotation of the motor 4 drives and brakes the pulsator 1 and washing/spinning tub 2 via a motor pulley 31, a belt 5, an impeller pulley 32, and a reduction mechanism/clutch 6.

There is a reduction ratio (e.g., 1/4) between the motor pulley 31 and the impeller pulley 32, so that when the motor pulley 31 attached to the motor shaft (not shown) of the motor 4 rotates four times, the impeller pulley 32 (or the washing and spin tub 2) attached to the impeller shaft (not shown) of the reduction mechanism/clutch 6 rotates once.

Similarly, the reduction gear mechanism/clutch 6 between the impeller pulley 32 and the pulsator 1 has a reduction ratio (e.g., 1/6), so that when the impeller pulley 32 attached to the impeller shaft rotates six times, the pulsator 1 attached to the pulsator shaft (not shown) rotates once. As for braking, in addition to a method of controlling the motor 4 so that a reverse torque is applied, there is a method of mechanically braking the washing/spinning tub 2 by operating the geared motor 7 and bringing the brake belt 8 into contact with the rotating part.

A panel section 10 is disposed above the washing machine outer frame 9. A lid 11 is configured on the top surface of the panel section 10 so that it can be opened and closed freely. A control device 13 is disposed on the inside front of the panel section 10, and the control device 13 controls the overall process of the washing machine and also has a display means 12.

The control device 13 has a control means 20 consisting of a microcomputer. The control means 20 controls the operation 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 spin-drying. The control means 20 executes acceleration control, constant speed control, and deceleration control of the motor 4. Based on information from an input setting means (not shown) through which a user operates a desired washing course setting, operation start, pause, etc., the control means 20 displays the progress of the process and various information on the display means 12 consisting of light-emitting elements such as LEDs and LCDs to inform the user. When the start of operation is set by the input setting means, the operation of the geared motor 7, the water supply valve 14, and the drain valve 15 is controlled according to data from a water level detection means (not shown) and the like to perform the washing operation.

[1-1-2. Configuration of motor and peripheral devices]
FIG. 2 is a block diagram of a drive system for a motor of the washing machine according to the first embodiment.

The AC power supply supplies AC power to the rectifier circuit 16, which is configured as a voltage doubler rectifier circuit, and supplies a doubled voltage DC voltage to the inverter circuit 17. The inverter circuit 17 is configured as a three-phase full-bridge inverter circuit consisting of six power switching semiconductors and anti-parallel diodes, and is usually configured as an intelligent power module (hereinafter referred to as IPM) that incorporates insulated gate bipolar transistors (IGBTs), anti-parallel diodes, and their drive circuits and protection circuits. 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, and detects the phase currents Iu, Iv, and Iw of the motor 4 based on the input current to the inverter circuit 17 calculated from the voltage across this shunt resistor. The DC voltage applied to the inverter circuit 17 is constantly being detected because it may be superimposed due to regenerative energy generated by motor rotation in addition to the input from the AC power source.

The PWM control means 19 controls the PWM signal that switches the IGBTs of the inverter circuit 17 in response 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.

Figure 3 is an equivalent circuit diagram of the motor of a washing machine in embodiment 1.

For simplicity, a two-pole configuration is used here, where one mechanical rotation corresponds to one electrical rotation. If the number of poles is changed to four, eight, etc., the relationship will change to one mechanical rotation corresponds to two, four, etc. electrical rotations. The motor 4 is a three-phase synchronous motor, and is configured with an equivalent circuit having three U-, V-, and W-phase windings 4a, 4b, and 4c, and a permanent magnet 4d, which is a rotor that rotates around the center of the rotation axis. In this equivalent circuit, the axis that passes through the N-pole side of the permanent magnet as the positive direction is defined as the d-axis (direct-axis), and the axis perpendicular to this is defined as the q-axis (quadrature-axis). With this definition, the magnetic field in the q-axis direction mainly governs the torque of the motor. The phase (electrical angle) is the rotation angle θr between the axis that passes through the U-phase winding and the d-axis. All phases described below are electrical angles. When a voltage is applied to generate a magnetic field in the d-axis direction, the inductance of the winding is Ld, and the inductance in the q-axis direction is Lq.

The interior magnet type three-phase synchronous motor has a relationship of Ld<Lq. Also, the control means 20 described later cannot accurately detect the rotor position at first, so as shown in FIG. 3, it assumes the phase to be θc, and there is an error Δθr from the actual phase θr. In other words, the axis that the microcomputer assumes to be the phase θc and controls is the γ-axis (estimated d-axis) and δ-axis (estimated q-axis) in contrast to the d-axis and q-axis of the actual motor. Hereinafter, 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, and the voltage component corresponding to the magnetic flux in the microcomputer is the command γ-axis voltage Vγs.

[1-1-3. Configuration of control means]
FIG. 4 is a control block diagram for estimating the phase of the motor of the washing machine in the first embodiment.

The control means 20 is composed of a microcomputer, an inverter control timer (timer) built into the microcomputer, A/D conversion, a memory circuit, a speed phase estimation means 21, a three-phase to two-phase converter 22, an Iδ error amplifier 23, an Iγ error amplifier 24, a two-phase 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 speed phase estimation means 21 will be described later. The speed phase estimation means 21 inputs the δ-axis current Iδ, the γ-axis current Iγ, and the command γ-axis voltage Vγs, and outputs an estimated speed ω (electrical angular velocity) and an estimated phase θ. All speeds described below are electrical angular velocities.

The three-phase to two-phase converter 22 calculates the γ-axis current Iγ and the δ-axis current Iδ from the electrical angle θ, the phase currents Iu, Iv, and Iw, and the sine wave data (sine and cosine data) required for conversion from the stationary coordinate system to the rotating coordinate system, as shown in Equation 1.

The Iδ error amplifier 23 receives the error ΔIδ from the δ-axis current command value Iδs obtained by the speed error amplifier 26 and the δ-axis current Iδ obtained by the three-phase to two-phase converter 22 relative to the δ-axis current command value Iδs, and outputs a command δ-axis voltage Vδs as the sum of the proportional component and the integral component.

Similarly, the Iγ error amplifier 24 receives the error ΔIγ from the γ-axis current command value Iγ obtained by the γ-axis current command Iγs calculated by the field weakening setting means 27 and the γ-axis current Iγ calculated by the three-phase 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 δ-axis current Iδ and γ-axis current Iγ and each is controlled independently.

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

The speed error amplifier 26 receives the speed command ωs and the error Δω from the estimated speed ω calculated by the speed phase estimation means 21, and outputs a δ-axis current command Iδs, which is the sum of the proportional component and the integral component.

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

Figure 5 is a detailed block diagram of the speed phase estimation means of the washing machine motor in embodiment 1.

The speed phase estimation means 21 calculates an estimated phase θ using the resistance value Ra and inductance value L of the windings 4a, 4b, and 4c, which are parameters of the motor 4. The speed phase estimation means 21 is composed of 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, resistance value Ra, δ-axis current Iδ, γ-axis current Iγ, command γ-axis voltage Vγs, and estimated speed ω according to Equation 3.

The γ-axis induced voltage command Veγs = 0, and the error ΔVeγ relative 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 the 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 the estimated phase θ.

However, the γ-axis induced voltage calculator 28 is not necessarily limited to using formula 3, and may perform calculations using formula 4, which includes a time differential term.

In addition, the inductance value L in each of the above formulas can be the same L value if the motor 4 has characteristics such that Ld = Lq. However, even if the motor 4 has a characteristic such that Ld ≠ Lq, a constant L value (= L
q) can be calculated as follows.

Figure 6(a) is a vector diagram of the state in which the estimated coordinates are delayed when estimating the phase of the motor of the washing machine in embodiment 1 (the γδ coordinates (estimated dq coordinates) are slightly delayed relative to the dq coordinates of motor 4), and Figure 6(b) is a vector diagram of the state in which the estimated coordinates are advanced when estimating the phase of the motor of the same washing machine (the γδ coordinates (estimated dq coordinates) are slightly advanced relative to the dq coordinates of motor 4).

In a vector diagram, the γ-axis induced voltage error ΔVeγ is the γ-axis component of the estimated induced voltage vector Ve (= ω × Ψa), which is the input voltage Va of the motor 4 minus the current drop flowing through Ra and ωL. Since the induced voltage vector Ve is always on the q-axis, when the estimated phase error Δθ (positive when the γδ coordinates are counterclockwise relative to the dq coordinates) is 0, the q-axis coincides with the δ-axis. In Figure 6(a), the estimated phase error Δθ is negative (Δθ < 0), and in Figure 6(b), the estimated phase error Δθ is positive (Δθ > 0).

The γ-axis induced voltage error amplifier 29 performs feedback control so that the γ-axis induced voltage error ΔVeγ and the estimated phase error Δθ become zero by increasing the estimated speed ω in the case of FIG. 6(a) and further advancing the estimated phase θ, and by decreasing the estimated speed ω and delaying the estimated phase θ in the case of FIG. 6(b). In this way, since phase estimation is premised on a motor rotation state with an induced voltage Ve, phase estimation is not stable in the low-speed range at start-up or stop when the induced voltage is low, and open-loop control that does not perform phase estimation is used in the low-speed range.

[1-2. Operation]
In the above configuration, the deceleration control of the motor 4 in the first embodiment will be described with reference to FIGS.

[1-2-1. Deceleration control]
FIG. 7 is a flowchart of the deceleration control of the washing machine in the first embodiment.

Deceleration control begins in step 500. In step 501, the process moves to a motor pause control processing routine (details of which will be described later). In step 502, the motor stop determination process checks whether the motor rotation speed N is smaller than the minimum detection rotation speed N_min (e.g., 10 r/min), and if it is smaller (YES), the process moves to step 503, where the deceleration control ends. If it is equal to or larger (NO), the process moves to step 501.

[1-2-2. Pause control processing routine]
8 is a flow chart of the motor pause control process of the washing machine in the first embodiment. The motor pause control process is started in step 700. In step 701, a fixed value is substituted for the command δ-axis current Iδs. In step 702, the current control timer Te_tm is cleared to 0. In step 703, the process proceeds to a current control process routine (details of which will be described later). In step 704, the current control process time (e.g., 0.1 ms) is added to the current control timer Te_tm. In step 705, it is confirmed whether the current control timer Te_tm is larger than the current control cycle Te_cycle. If it is larger (YES), the process proceeds to step 706, and if it is equal to or smaller (NO), the process proceeds to step 703. In step 706, the motor pause control process is ended.

The fixed value substituted for the command δ-axis current Iδs in step 701 will be described below. There are three methods for substituting 0, a negative fixed value, and a small positive fixed value as the fixed value of the command δ-axis current Iδs. 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 δ-axis current Iδs is used to generate a brake torque to an extent that the regenerative voltage does not become a problem, and to shorten the brake time. The method of substituting a small positive fixed value for the command δ-axis current Iδs is used to prevent excessive brake torque from being applied to the inertial rotation by the method using a negative fixed value. As an example of the purpose of using a positive fixed value, in a method in which a spring is tightened in the rotation direction of the washing and spin-drying tub 2 and a clutch is switched to the washing and spin-drying tub 2 side, a brake torque is applied in the direction opposite to the rotation direction of the washing and spin-drying tub 2, and the spring is loosened, thereby preventing the clutch on the washing and spin-drying tub 2 side from being released. Incidentally, the method of substituting 0, the method of substituting a negative fixed value, and the method of substituting a small positive fixed value for the command δ-axis current Iδs can be selected according to the amount of laundry and the configuration of the washing machine, whichever is easier to use.

[1-2-3. Current control processing routine]
FIG. 9 is a flowchart of the motor current control process of the washing machine in the first embodiment.

The motor current control process starts in step 800. In step 801, the current detection means 18 detects the phase currents Iu, Iv, and Iw, and in step 802, the three-phase to two-phase converter 22 calculates the δ-axis current Iδ according to formula 1. In step 803, it is confirmed whether the δ-axis current Iδ is larger than the command δ-axis current Iδs, and if it is larger (YES), the process proceeds to step 804, where the command δ-axis voltage Vδs is reduced. In step 803, if the δ-axis current Iδ is equal to or smaller than the command δ-axis current Iδs (NO), 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 unstable, so proportional-integral control is usually performed with the addition of an integral element such as averaging.

After that, the voltage of the γ-axis is calculated in steps 806 to 809 in the same way as the δ-axis. In step 806, the 3-2-phase converter 22 calculates the γ-axis current Iγ according to Equation 1. In step 807, it is confirmed whether the γ-axis current Iγ is larger than the command γ-axis current Iγs, and if it is larger (YES), the process proceeds to step 808, and if it is equal to or smaller (NO), the process proceeds to step 809. In step 808, the command γ-axis voltage Vγs is reduced. In 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 unstable, so proportional-integral control is usually performed by adding an integral element such as averaging.

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

[1-3. Effects, etc.]
As described above, in this embodiment, washing machine 100 includes washing/spin-drying tub 2, pulsator 1, motor 4, inverter circuit 17, current detection means 18, and control device 13. Pulsator 1 is rotatably disposed in washing/spin-drying tub 2. Motor 4 has permanent magnet 4d, winding 4a, winding 4b, and winding 4c, and drives washing/spin-drying tub 2 and pulsator 1 to rotate. Inverter circuit 17 supplies current to motor 4. Current detection means 18 detects the current of motor 4. Control device 13 executes acceleration control, constant speed control, and deceleration control of motor 4. The deceleration control includes pause control, and control device 13 estimates the estimated speed ω of motor 4 by PWM-controlling motor 4 so that δ-axis current Iδ is constant during the pause control period.

This makes it possible to estimate the timing at which the motor 4 will stop, and to determine the timing to transition to the next stroke after the motor 4 has stopped. This makes it possible to shorten the operation time.

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

This prevents the motor 4 from generating torque.

As in this embodiment, during the pause control period, the control device 13 may compare the rotation speed N of the motor 4 calculated from the estimated speed ω with the minimum detectable rotation speed N_min, and terminate the deceleration control if the rotation speed N is smaller than the minimum detectable rotation speed N_min.

This allows the control device 13 to determine the timing to transition to the stroke after the motor 4 is stopped during deceleration control.

(Embodiment 2)
The second embodiment will be described below with reference to Fig. 10. In the second embodiment, the deceleration control of the motor 4 is different from that in the first embodiment.

[2-1. Operation]
[2-1-1. Deceleration control]
FIG. 10 is a flowchart of deceleration control of the washing machine in the second embodiment.

In step 900, deceleration control is started. In step 901, the process moves to a motor pause control processing routine. In step 902, the motor rotation speed N is checked as a motor stop determination process to see if it is smaller than the minimum detection rotation speed N_min (e.g., 10 r/min), and if it is smaller (YES), the process moves to step 903. If it is equal to or larger (NO), the process moves to step 901. In step 903, the time measurement counter tm is incremented, and in step 904, the time measurement counter tm is compared with the delay time delay_tm. In step 904, if the time measurement counter tm is larger than the delay time delay_tm (YES), the deceleration control is terminated. In step 904, if the time measurement counter tm is equal to or smaller than the delay time delay_tm (NO), the process moves to step 903. In steps 903 and 904, the motor 4 is not paused and the motor 4 rotates by inertia.

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

This allows for even more accurate determination of when motor 4 has stopped.

Other Embodiments
As described above, the first and second embodiments have been described as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. In addition, it is also possible to combine the components described in the first and second embodiments to create new embodiments.

Therefore, other embodiments are given below as examples.

In the first and second embodiments, the minimum detectable rotation speed N_min is set to a predetermined value (e.g., 10 r/min), but it may be set to the rotation speed N at the point when the variation in the estimated phase θ becomes larger than a predetermined value. This is because, near the minimum detectable rotation speed N_min, the input voltage Va of the motor 4 becomes small and the γ-axis induced voltage error ΔVeγ becomes small, which causes the variation in other elements to become large with respect to the γ-axis induced voltage error ΔVeγ, resulting in variation in the estimated phase θ.

This allows the control device 13 to reduce the influence of factors such as the amount of clothes in the washing and spin-drying tub 2 and perform deceleration control of the motor 4.

In the first and second embodiments, a pulsator-type vertical washing machine is described as an example in which a motor pulley 31 and an impeller pulley 32 are connected by a belt 5, and the speed reducer/clutch 6 is connected to a pulsator 1 or a washing/spinning tub 2. However, the washing machine may be a direct drive type washing machine in which the washing/spinning tub and the motor are coaxial, or an agitator-type vertical washing machine may be used.

This disclosure is applicable to vertical washing machines that can shorten the operating time. Specifically, this disclosure is applicable to pulsator-type vertical washing machines and agitator-type vertical washing machines.

1 Pulsator (mixing blade)
2 Washing and spin-drying tub 3 Water receiving tub 4 Motor (electric motor)
4a Winding 4b Winding 4c Winding 4d Permanent magnet (rotor)
5 Belt (transmission mechanism)
6. Reduction mechanism/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 to two-phase converter 23 Iδ error amplifier 24 Iγ error amplifier 25 Two-phase to 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 (2)

Washing and drying tub,
An agitator blade rotatably disposed in the washing and spin-drying tub;
an electric motor having a permanent magnet and a winding for rotating the washing/spinning tub and the agitating blade;
a power supply circuit for supplying current to the electric motor;
A current detection unit that detects a current of the electric motor;
a speed phase estimating means for outputting an estimated speed and an estimated phase of the electric motor;
a control unit that controls the electric motor based on the estimated speed and the estimated phase ;
Equipped with
the control unit executes acceleration control, constant speed control, and deceleration control including pause control of the electric motor, estimates the estimated speed of the electric motor by PWM controlling the electric motor so that a current of a torque component becomes zero during a period of the pause control , calculates a rotation speed of the electric motor from the estimated speed, and terminates the deceleration control when the calculated rotation speed of the electric motor becomes smaller than a predetermined rotation speed.
washing machine. the control unit terminates the deceleration control after a predetermined time has elapsed since the rotation speed of the electric motor becomes lower than the predetermined rotation speed .
The washing machine according to claim 1 .