JP7093071B2 - washing machine - Google Patents

Description

The present invention relates to a washing machine capable of easily and accurately determining an eccentric state even without a sensor.

If the distribution of laundry in the dehydration tub of the washing machine is uneven, it causes a large vibration when the dehydration operation is performed. When the dehydration tank is rotationally driven to perform the dehydration process, it is necessary to stop the rotation because excessive vibration occurs when the laundry is eccentric.

Therefore, as a method for detecting an eccentric state without a sensor and controlling the rotation to be stopped when necessary, for example, a method disclosed in Patent Document 1 is known.

This method focuses on the fact that there is a correlation between the q-axis current of the motor calculated for vector control and the eccentric state, and is configured to determine the occurrence of abnormal vibration based on the q-axis current. ing.

Japanese Patent No. 4406176

However, since the q-axis current appears as a result of voltage control, it is easily affected by external noise and its absolute value does not change much. Therefore, if the eccentric state is determined based on the q-axis current, erroneous determination is likely to occur.

Therefore, the present inventor focused on the d-axis voltage. The d-axis voltage is an operation amount of the q-axis current, and changes depending on the eccentric state like the q-axis current. Moreover, since it is an operation amount, it is not easily affected by external noise, and the change as an absolute value is large.

However, since the d-axis voltage fluctuates more than the q-axis current, if the eccentric state is determined depending only on the d-axis voltage, the possibility of erroneous determination still remains.

Based on such new knowledge, the present invention makes an appropriate complement when determining the eccentric state by the d-axis voltage, and in some cases, the eccentric state is equal to or in place of the d-axis voltage. The purpose is to realize a washing machine that uses a new determination method capable of determining the eccentric state.

In order to achieve the above object, the washing machine according to the present invention includes a motor for rotationally driving the dehydration tub and control means for vector-controlling the torque generated by the motor. An eccentricity determination unit for determining an eccentric state of the dehydration tank is provided, and the eccentricity determination unit includes a first value based on a d-axis voltage generated in performing the vector control, and a preset first value. The phase error between the d-axis phase estimated for performing the vector control and the actual d-axis phase when the first value is equal to or higher than the first threshold value by comparing with the threshold value. The feature is that the eccentricity of the dehydration tank is determined to be large when the second value based on the second value is compared with the preset second threshold value and the second value is equal to or higher than the second threshold value. do.

Further, in the washing machine according to the present invention, the first value is the d-axis voltage generated for performing the vector control when the dehydration tank is rotating at the first rotation speed exceeding the resonance rotation speed. The difference between the reference value based on the value and the value based on the d-axis voltage generated when performing the vector control when the dehydration tank is rotating at a second rotation speed higher than the first rotation speed. It is characterized by.

Further, in the washing machine according to the present invention, when the rotation speed of the dehydration tank is in the ultra-high speed rotation range exceeding 1000 rpm, the eccentricity determination unit has a third rotation speed at which the dehydration tank exceeds the resonance rotation speed. The first reference value based on the d-axis voltage generated for performing the vector control during rotation and the fourth rotation speed larger than the third rotation speed when the dehydration tank is rotating. The first difference with the value based on the d-axis voltage generated in performing the vector control is calculated, the first difference is compared with the preset third threshold, and the first difference is the third threshold. In the above case, or when the dehydration tank is rotating at a third rotation speed exceeding the resonance rotation speed, the phase error between the phase of the d-axis estimated for performing the vector control and the phase of the actual d-axis The second reference value based on the above, the phase of the d-axis estimated to perform the vector control when the dehydration tank is rotating at the fourth rotation speed higher than the third rotation speed, and the actual d-axis. The second difference from the value based on the phase error with the phase is calculated, the second difference is compared with the preset fourth threshold value, and when the second difference is equal to or more than the fourth threshold value, the said It is characterized in that it is determined that the eccentricity of the dehydration tank is large .

Further, in the washing machine according to the present invention, in each of the above configurations, the value of the Fourier coefficient corresponding to the actual frequency among the Fourier series expansions for the waveform of the phase error is used as the phase error. It is a feature.

The washing machine of the present invention determines the eccentric state based on the value based on the d-axis voltage and the magnitude of the phase error between the phase of the d-axis and the actual phase of the d-axis. The phase error does not fluctuate as much as the d-axis voltage, and increases or decreases depending on the eccentric state. Therefore, according to the present invention, the biased state can be determined from a viewpoint different from that in the case of monitoring the d-axis voltage. Therefore, it is possible to make an appropriate complement when determining the eccentric state based on the d-axis voltage, and in some cases, determine the eccentric state on an equal footing with the d-axis voltage or instead of the d-axis voltage. The phase error tends to appear large when accelerating in the low speed range.
In addition, the d-axis voltage may be large due to other factors, and at this time, the phase error does not fluctuate significantly. Therefore, according to the present invention, the determination based on the d-axis voltage can be complemented by the phase error, and the eccentric state can be determined more accurately. Another factor is the so-called "water bite" condition in which water remains between the dehydration tank and the outer tank due to poor drainage.

Further, since the washing machine of the present invention Fourier transforms the waveform of the phase error to extract the phase error corresponding to the actual frequency, it is possible to eliminate noise and make a highly accurate determination.

The perspective view which shows the appearance of the washing machine which concerns on one Embodiment of this invention. The vertical sectional view which shows the schematic structure of the washing machine. The block diagram which shows the system configuration of the motor control system which is the precondition configuration of the load measurement in the same embodiment. The figure which shows the schematic structure of the speed estimation part in the motor control system. The figure which shows the speed estimation principle in the motor control system. The figure which shows the outline of the PLL control part in the motor control system. The sequence diagram which shows the control process at the time of the dehydration process of the washing machine. The flowchart which shows the processing procedure of low-speed region determination 1 in the same embodiment. The flowchart which shows the processing procedure of low-speed region determination 2 in the same embodiment. The flowchart which shows the processing procedure of high-speed region determination 1 in the same embodiment. The flowchart which shows the processing procedure of high-speed region determination 2 in the same embodiment. The graph which showed the transition of the detection value of the d-axis voltage when the low speed region determination 1 was not applied in the C section in the case of small eccentricity amount and the case of large eccentricity amount. The graph which showed the transition of the phase error when the low speed region determination 2 was not applied in the C section in the case of small eccentricity amount and the case of large eccentricity amount. The graph which showed the transition of the d-axis voltage and the phase error Δθ when the high-speed region determination 1 was not applied in the D section in the case of a small eccentricity amount and the case of a large eccentricity amount. The graph which showed the transition of the d-axis voltage and the phase error Δθ when the high-speed region determination 2 was not applied in the D section in the case of a small eccentricity amount and the case of a large eccentricity amount.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing the appearance of a vertical washing machine (hereinafter referred to as “washing machine”) 1 according to an embodiment of the present invention. Further, FIG. 2 is a vertical sectional view showing a schematic configuration of the washing machine 1 of the present embodiment.

As shown in FIG. 2, the washing machine 1 of the present embodiment includes a washing machine main body 11, an outer tub 12, a dehydration tub (washing tub) 13, a drive unit 16, and a control means C (see FIG. 3). To prepare for. Such a washing machine 1 automatically determines the amount of laundry in the dehydration tub 13 as a load amount when a start key (not shown), which is in the input unit 14 and performs washing fully automatically, is pressed, and uses the load amount as the load amount. Based on this, the amount of water stored in the outer tub 12 is automatically determined in the washing step and the rinsing step, and the washing operation is performed. After that, in the dehydration process, after low-speed rotation, the control shifts to sensorless control, and while monitoring the eccentric state of the dehydration tank 13 sensorlessly, if there is an eccentricity abnormality, the rotation is stopped, and if there is no eccentricity abnormality, the maximum speed is reached. Accelerate to.

FIG. 3 is a functional block showing an outline of the control means. In the present embodiment, the eccentricity determination unit 100 is provided for determining the eccentric state, and the eccentricity determination unit 100 uses the value of the d-axis voltage instead of the value of the q-axis current, and is estimated in terms of control. The phase error Δθ between the d-axis and the actual d-axis is used. For the Vd value and Δθ value, a process of removing rapidly changing data is performed by a low-pass filter, a moving average process, or the like, if necessary. Hereinafter, the explanation will be given step by step.

The washing machine main body 11 has a substantially rectangular parallelepiped shape, and has an opening 11b for taking in and out laundry (clothes) to and from the dehydration tub 13 and an opening / closing lid 11c capable of opening and closing the opening 11b on the upper surface 11a. By opening the opening / closing lid 11c, the laundry can be taken in and out of the dehydration tub 13 through the opening 11b. Further, the above-mentioned input portion 14 is formed on the upper surface 11a of such a washing machine main body 11.

The outer tub 12 shown in FIG. 2 is a bottomed cylindrical member that can store water and is arranged inside the washing machine main body 11.

The dehydration tub 13 as a washing tub is a bottomed cylindrical member that is arranged coaxially with the outer tub 12 inside the outer tub 12 and is rotatably supported by the outer tub 12. The dehydration tank 13 has a smaller diameter than the outer tank 12, and has a large number of water passage holes (not shown) on the wall surface 13a thereof.

A pulsator (stirring blade) 15 is rotatably arranged in the center of the bottom 13b of such a dehydration tank 13. The pulsator 15 stirs the water stored in the outer tank 12 to generate a water flow.

Further, the pulsator 15 is rotationally driven at the start of the washing process and before water is supplied to the dehydration tank 13, and the detection value acquired by the rotation of dragging the laundry at this time is the detection of the load amount. Used for.

The drive unit 16 includes a motor M and a clutch 16b. The motor M rotates the dehydration tank 13 by rotating the drive shaft m extending toward the bottom 13a of the dehydration tank 13. Further, the motor M can also apply a driving force to the pulsator 15 by switching the clutch 16b to rotate the pulsator 15. Therefore, the washing machine 1 can mainly rotate only the pulsator 15 in the washing step and the rinsing step at the time of measuring the load amount described later, and can integrally rotate the dehydration tub 13 and the pulsator 15 at high speed in the dehydration step.

…（１） The following is the voltage equation of a permanent magnet type synchronous motor. Only in this equation, each velocity ω is expressed as ωe.

… (1)

In this equation, if it is regarded as steady rotation and the differential term is ignored,
Vd = R ・ Id－ω ・ Lq ・ iq… (2)
Vq = ω ・ Ld ・ id + R ・ iq + ω ・ Φ… (3)

Furthermore, if ω is large and the voltage drop due to R is negligible,
Vd = -ω ・ Lq ・ iq ... (4)
Vq = ω ・ Ld ・ id + ω ・ Φ… (5)

If the weakening magnetic flux control has not started, it is usually controlled by id ≈ 0, so
Vq ≒ ωΦ ... (6)

It is also described in Patent Document 1 that iq depends on the eccentric state, but as is clear from Eq. (4), the state change of the d-axis voltage Vd, which is the manipulated amount of the q-axis current Iq, also It depends on the eccentric state.

In particular, since the d-axis voltage Vd is a control operation amount and does not appear as a result of control unlike the q-axis current Iq, there is an advantage that it is not easily affected by external noise or the like. Therefore, in this embodiment, the d-axis voltage Vd is used to determine the eccentric state.

However, as a drawback compared to the case where the q-axis current Iq is used, the fluctuation tends to be large. Therefore, in determining the eccentric state, it is necessary to use the calculated value as the integrated value or the average value instead of using the instantaneous value, and the d-axis estimated by control and the actual d-axis The phase error Δθ is also added to the judgment factor. The phase error Δθ is a state in which the phase of the applied voltage of the three phases is out of phase with the actual phase of the dehydration tank 13, and the control system controls the phase error Δθ to be 0, but the phase error Δθ converges. If not, it can be said that a large eccentric state or vibration has occurred. That is, the phase error can be treated as a parameter that reflects the eccentric state.

Therefore, the eccentricity determination unit 100 determines the eccentric state based on the magnitude of the phase error Δθ and the degree of change in the phase error Δθ. Alternatively, the eccentricity determination unit 100 has a value obtained by correcting the d-axis voltage by a load, and a phase error Δθ between the d-axis phase estimated by the torque control means for vector control and the actual d-axis phase. The eccentric state is determined based on the correlation with.

This makes it possible to supplement or replace the drawbacks of using the d-axis voltage Vd, which is not easily affected by disturbance but has a large fluctuation, and lead to an appropriate determination result.

FIG. 3 is a sensorless vector control block diagram showing the control means C according to the present invention, and the d-axis voltage Vd and the phase error Δθ for determining the eccentric state are calculated in this control block. First, this control block will be described.

The basic configuration of the control means C is a torque command generation unit 2 that generates a torque command based on the deviation between the motor rotation speed command value ω ^* _m given as a control amount and the motor rotation speed estimated value ω _m , and a torque command generation unit 2 during driving. The deviation between the motor current Iq (Id) and the current command value Iq ^* (Id) corresponding to the torque command value T ^* is converted into the motor voltage command values V ^* q and V ^* d, which are control operation amounts, and the motor M. Estimating the motor rotation speed ω _m and the phase error Δθ using the motor drive control unit 3 for driving the motor and the motor voltages Vq and Vd related to the motor currents Iq and Id and the motor voltage command values V ^* q and V ^* d. A device 4 is provided, and the estimator 4 is configured in a feedback loop 5. The torque command generation unit 2 and the motor drive control unit 3 are generally referred to as components of an inverter controller. Further, here, it is treated as assuming that the motor voltages Vq and Vd equal to the motor voltage command values V ^* q and V ^* d are generated.

In the torque command generation unit 2, first, the rotation speed command ω ^* m given from the microcomputer 6 that controls the overall operation of the washing machine 1 and the estimated speed value ω _m estimated from the motor driving state are input to the subtractor 21. The difference output of the subtractor 21 is input to the speed controller 22.

The speed controller 22 generates a torque command T ^* by PI control based on the difference between the rotation speed command ω ^* _m and the estimated speed ω _m in order to control the rotation speed of the motor M to the target value.

The torque command T ^* generated by the torque command generation unit 22 is input to the motor drive control unit 3.

The motor drive control unit 3 drives the voltage under the coordinate system (d, q) of the magnetic poles that rotate with the rotation of the rotor of the synchronous motor M.

First, the torque command value T ^* is set to the q-axis current command value _Iq ^* by multiplying the torque coefficient 1 / KE in the gain multiplication unit 31, and is input to the q-axis current controller 33 via the subtractor 32. .. Generally, a command value Id = 0 is output from the d-axis current command unit 34 and input to the d-axis current controller 36 via the subtractor 35. The q-axis current value Iq output from the second converter 51 described later, which performs [uvw → dq] conversion, is given to the subtractor 32 as a subtraction value, and the subtractor 35 is given the second value. The d-axis current value Iq output from the converter 51 is given as a subtraction value.

The q-axis current controller 33 generates the q-axis voltage command value Vq ^* by performing PI control based on the difference between the q-axis current command value Iq ^* and the q-axis current value Iq. The d-axis current controller 36 generates a d-axis voltage command value Vd ^* by performing PI control based on the difference between the d-axis current command value Id ^* (= 0) and the q-axis current value Iq. Then, it is input to the first converter 37 that performs [dq → uvv] conversion in order to convert it into a three-phase voltage command.

The first converter 37 is given an estimated rotor rotation phase angle θ obtained by integrating the motor electric angular velocity ω _e output from the estimator 4 described later with the integrator 44. Then, q, d voltage command values Vq ^* , Vd ^* are converted into three-phase voltage command values Vu, Vv, Vw based on the estimated rotor rotation phase angle θ, and the motor M is energized via the motor excitation circuit 38.

On the other hand, the feedback loop 5 detects the phase currents Iu, Iv, and Iw through the phase current detection unit 50 provided in the motor excitation circuit 38, and performs the second conversion to perform [uvv → dq] conversion. Input to the device 51. The second converter 51 is given an estimated rotor rotation phase angle θ obtained by integrating the motor electric angular velocity ω _e output from the estimator 4 described later with the integrator 44, so that the phase current value is q. Convert to d-axis current values Id and Iq. These q and d-axis current values are input to the subtractors 35 and 32, respectively.

On the other hand, the estimator 4 includes a rotor phase error estimator 41 and a PLL (Phase Locked Loop) controller 42 as shown in FIG. The rotor phase error estimator 41 calculates the estimated phase error Δθ using the motor voltage Vd (= Vd ^* ), Vq (= Vq ^* ), the motor currents Id, Iq, the motor parameters R, L, and the like. R is the motor winding resistance, and L is the motor winding inductance.

When the motor M is a permanent magnet synchronous motor, as shown in the coordinate system of FIG. 5, the rotor rotates at an electric angular velocity ωn in the dq rotating coordinate system with respect to the rest coordinate systems α and β. On the other hand, a rotation speed estimation algorithm generally called a sensorless algorithm estimates the rotation coordinates of γ-δ. Although the magnetic pole is actually on the d-axis, when it is estimated that the magnetic pole is on the γ-axis, a phase error of Δθ is generated between the estimated d-axis and the actual d-axis.

The estimator 41 uses the following equation as an example.
Δθ ＝ tan ^-1 {(Vd-R ・ Id + ω _γ・ L ・ Iq) / (Vq-R ・ Iq-ω _γ・ Li ・ d)}… (7)
The phase error Δθ is calculated based on.

In order to rotate the motor M stably, the position of the dq axis must be located and the r−δ axis recognized by the control means 1 must be matched. That is, it is necessary to aim for Δθ → 0.

Therefore, the PLL controller 42 is used. The contents of the PLL controller 42 are shown in FIG.

The PLL controller 42 uses PI control. ω _γ is the angular velocity (angular frequency) of the three-phase voltage applied to the motor by the motor drive control unit 3, and naturally the motor drive control unit 3 can output a free value by the inverter method. As can be seen from FIG. 5, when ω _γ increases, Δθ → large due to the velocity difference from ω _n , and when ω _γ decreases, Δθ → small.

FIG. 7 shows a sequence from the start at the time of dehydration, with time on the horizontal axis and rotation speed on the vertical axis. Synchronous rotation control is performed in the A section, and after the synchronization is completed in the B section, the process shifts to the sensorless vector control in the C section and the D section. The C section is operated in the low speed mode, and the D section is operated in the high speed mode.

As described above, this embodiment utilizes the d-axis voltage input to the estimator 4 shown in FIG. 3 and the phase error Δθ estimated by the estimator 4. The d-axis voltage Vd and the phase error Δθ are updated for each carrier frequency which is the fundamental frequency of control, but in this detection, the d-axis voltage V and the phase error Δθ are extracted from the estimator 4 every predetermined time, for example, every 10 ms. Then, it is input to the eccentricity determination unit 100.

The eccentricity determination unit 100 is configured to execute a program or data for performing eccentricity determination in advance by utilizing the d-axis voltage Vd and the phase error Δθ. In the eccentricity determination unit 100, the low speed region determination 1 and the low speed region determination 2 are executed in parallel in the C section, the high speed region determination 1 is executed from the first half in the D section, and the ultrahigh speed region determination is executed from the second half. 2 are executed in parallel.

8 to 11 are flowcharts showing a processing procedure of eccentricity determination executed by the eccentricity determination unit 100 for each section.

(Low speed range judgment 1)
First, the processing procedure of the low speed range determination 1 will be described with reference to FIG.
Enter the C section and start the judgment flow with the acceleration started.

<Step S11>
First, the eccentricity determination unit 100 measures the maximum value of the Vd value in step S11. Since the Vd value is almost proportional to the load amount, the Vd value can be estimated as the load amount.

<Step S12>
After the measurement of the maximum value of the Vd value is completed, the eccentricity determination unit 100 integrates the Vd value after a certain period of time.

<Step S13>
Next, the eccentricity determination unit 100 corrects the integrated value according to the maximum value calculated in step S11, that is, the load amount. For example, when the integrated value is Vd _int , the maximum value is Vd _max , the counter value of the measurement counter is CT, and the load amount correction value is Vd _amd , the correction formula is as follows.
Vd _amd = Vd _int + (30-Vd _max ) × 0.3 × (CT-40)… (8)
Calculate as. The CT count starts at the time of step S11, and after acquiring the maximum value Vd _max in CT (0 to 40), step S13 is executed in CT> 40. As a result, the integrated value Vd _int including the load amount is subtracted from the value obtained by multiplying the maximum value Vd _max including the load amount by a coefficient, so that the load amount is partially offset.

<Step S14>
The eccentricity determination unit 100 compares the load amount correction value Vd _amd calculated in step S13 with the preset threshold value. Then, if the load amount correction value Vd _amd is equal to or more than the threshold value, it is determined that the eccentricity amount is large and the process proceeds to step S15.

<Step S15>
In step S15, the eccentricity determination unit 100 issues a dehydration tank rotation stop command and ends. This command interrupts the dehydration sequence and stops the rotation. To stop the rotation, necessary processing is performed such as setting the rotation speed command ω ^* m shown in FIG. 4 to 0 and applying mechanical braking by a brake mechanism (not shown). The same applies hereinafter.

Normally, when the amount of eccentricity is small, the Vd value sharply decreases after the maximum value appears. Therefore, the values after the processing of steps S12 and S13 are low. However, when the amount of eccentricity is large, the decrease in Vd value becomes small. Therefore, the values after the processing of steps S12 and S13 exceed the threshold value.

(Low speed range judgment 2)
Next, the processing procedure of the low speed region determination 2 will be described with reference to FIG. The flow of FIG. 9 starts at any time from the time when the C section is entered and acceleration is started, and is repeatedly executed.

<Step S21>
First, the eccentricity determination unit 100 measures the phase error Δθ.

<Step S22>
Next, the eccentricity determination unit 100 compares the phase error Δθ with a preset threshold value. Then, if the phase error Δθ is equal to or greater than the threshold value, the process proceeds to step S23, and if it is less than the threshold value, step S23 is skipped.

<Step S23>
Here, the eccentricity determination unit 100 issues a dehydration tank rotation stop command and ends. This command interrupts the dehydration sequence and stops dehydration.

Therefore, even if the fluctuation of the Vd value happens to be small in the flowchart of FIG. 8 and the eccentricity abnormality is overlooked, the eccentric state can be reliably determined by complementing with θ in the flowchart of FIG. can.

(High-speed range judgment 1)
Next, the processing procedure of the high-speed range determination 1 will be described with reference to FIG. In FIG. 10, first, the procedure according to the flowchart of (a) is executed, and then the procedure according to the flowchart of (b) is executed.

<Step S31>
In the procedure (a), the eccentricity determination unit 100 starts at any time after entering the D section, and determines whether or not the rotation speed has reached a predetermined rotation speed, for example, 400 rpm. If YES, the determination in step 32 is repeated, and if NO, the determination in step S31 is repeated.

<Step S32>
Here, the eccentricity determination unit 100 measures, stores, and ends the Vd value. Once this step S32 is performed, the procedure (a) does not have to be executed. The measurement of the Vd value at 400 rpm is an estimated value of the load amount, and is set based on the rotation speed at which the rotation is stable beyond the resonance rotation speed and the load amount can be estimated without being affected by the eccentric load. It has been done.

However, if there is a risk that the error will increase if the Vd value is judged only once, the average of the determined sections in step S32, for example, the average value of the Vd values during a change of 100 rpm, that is, between 400 and 500 rpm. May be used. Further, the rotation speed does not have to be 400 to 500 rpm.

Subsequently, the eccentricity determination unit 100 starts the procedure of FIG. 10B at any time. Here, the Vd value is measured at any time, and the eccentricity amount is determined based on the difference from the Vd value regarded as the previous load amount.

<Step S41>
First, the eccentricity determination unit 100 determines whether or not the rotation speed has reached 500 rpm in step S41. If YES, the process proceeds to step S42, and if NO, the determination in step S41 is repeated.

<Step S42>
Here, the eccentricity determination unit 100 measures the Vd value. If this measurement is judged by the Vd value only once and the error may be large, the average of the determined sections in step S42, for example, the Vd value between 500 and 550 rpm while changing by 50 rpm is used. You may measure and use the average value. Then, the process proceeds to step S43.

<Step S43>
The eccentricity determination unit 100 calculates the difference between the Vd value measured in step S42 and the Vd value regarded as the load amount, and compares this difference with the preset threshold value. Then, when the difference is equal to or more than the threshold value, the rotation stop command is not immediately issued, but the process proceeds to step S44, and when the difference is less than the threshold value, the process ends.

<Step S44>
Here, the eccentricity determination unit 100 measures the phase error Δθ. The phase error Δθ may be measured not only once but multiple times and the average value may be taken. In this case, the same processing as the above-mentioned Vd value may be performed. Since the phase error Δθ does not change much as compared with the d-axis voltage Vd, it tends not to require an average of as many values as the d-axis voltage Vd. Alternatively, the value of the Fourier coefficient corresponding to the actual frequency (rotation number) of the Fourier series expansion with respect to the phase error waveform may be used as the phase error Δθ. If the value of the Fourier coefficient is used, noise can be eliminated and a highly accurate judgment can be made. Then, the process proceeds to step S45.

<Step S45>
In step S45, the eccentricity determination unit 100 determines whether or not the phase error Δθ is equal to or greater than the threshold value. If it is equal to or more than the threshold value, it is treated as having a large eccentricity and proceeds to step S46, and if it is less than the threshold value, it is treated as a so-called water biting state and proceeds to step S47. The water-bite state is a state in which water remains between the dehydration tank and the outer tank due to poor drainage as described above.

<Step S46>
In step S46, the eccentricity determination unit 100 issues a rotation stop command for the dehydration stop tank and ends. The rotation stop command interrupts the dehydration sequence and stops the dehydration process.

<Step S47>
In step S47, the eccentricity determination unit 100 issues a command to maintain a predetermined rotation speed for a predetermined predetermined time and ends. This command interrupts the dehydration sequence, maintains a predetermined number of revolutions for a certain period of time, and then increases the number of revolutions after that time. If the rotation speed is increased in the water-biting state, the water-biting state is further deteriorated. Therefore, the increase in the rotation speed is stopped, and the predetermined rotation speed is maintained to promote drainage.

In this way, since the eccentric state is determined by the correlation between the d-axis voltage Vd and the phase error Δθ, it is possible to avoid an unnecessary stop command.

(High-speed range judgment 2)
Next, the processing procedure of the high-speed range determination 1 will be described with reference to FIG. In FIG. 11, first, the procedure according to the flowchart of (a) is executed, and then the procedure according to the flowchart of (b) is executed.

<Step S51>
In the procedure (a), the eccentricity determination unit 100 starts at any time after entering the D section, and determines whether or not the rotation speed has reached a predetermined rotation speed, for example, 1000 rpm. If YES, the determination in step 52 is repeated, and if NO, the determination in step S61 is repeated.

<Step S52>
Here, the eccentricity determination unit 100 measures, stores, and ends the Vd value and the θ value. Once this step S52 has been performed, the procedure (a) does not have to be executed. When the rotation speed goes from 1000 rpm to the ultra-high speed rotation range, the influence of the eccentric load becomes larger than that at the time of normal high speed rotation. Therefore, the above value at 1000 rpm is set as a reference at the entrance toward the ultra-high speed rotation range.

However, if there is a risk that the error will be large if the judgment is made based only on the Vd value and θ value only once, the same average value as above may be used.
Subsequently, the eccentricity determination unit 100 starts (b) at any time, for example, every 2 seconds. Here, Vd and θ are measured at any time, and the eccentricity amount is determined based on the difference between the Vd value and the θ value, which are the reference at 1000 rpm.

<Step S61>
First, the eccentricity determination unit 100 waits in step S61 whether or not a predetermined time has elapsed from the start. If YES, the process proceeds to step S62, and if NO, the determination in step S61 is repeated.

<Step S62>
Here, the eccentricity determination unit 100 measures the Vd value and the θ value. If there is a possibility that the error will be large if this measurement is also judged by the Vd value only once, the same average value as above may be used. Then, the process proceeds to step S63.

<Step S63>
Here, the eccentricity determination unit 100 calculates the difference between the Vd value measured in step S52 and the Vd value measured every 2 seconds in step S62, and compares this difference with the preset threshold value. Then, if it is equal to or more than the threshold value, the process proceeds to step S64, and if it is less than the threshold value, the process proceeds to step S65 instead of immediately ending.

<Step S64>
Here, the eccentricity determining unit 100 considers that the amount of eccentricity is large, issues a command to stop the rotation of the dehydration tank, and ends. This command interrupts the dehydration sequence and stops dehydration.

<Step S65>
Here, the eccentricity determination unit 100 calculates the difference between the Δθ value measured in step S52 and the Δθ value measured every 2 seconds in step S62, and compares this difference with the preset threshold value. Then, if it is equal to or more than the threshold value, the process proceeds to step S64, and if it is less than the threshold value, the process ends.

In this way, the degree of change in the d-axis voltage Vd and the degree of change in the phase error Δθ are monitored, and if any of them is equal to or greater than the threshold value, it is treated as an eccentricity abnormality. The captured judgment becomes possible.

FIG. 12 is a graph showing the transition of the detected value of the d-axis voltage when the low speed region determination 1 is not applied in the C section when the eccentricity amount is small and when the eccentricity amount is large. FIG. 13 is a graph showing the transition of the phase error Δθ when the low speed region determination 2 is not applied in the C section when the eccentricity amount is small and when the eccentricity amount is large. FIG. 14 is a graph showing the transition of the d-axis voltage and the phase error Δθ when the high-speed region determination 1 is not applied in the D section, when the eccentricity is small and when the eccentricity is large. Of the graphs of FIG. 14, the upper graph is for a load of 10 kg, and the graph in the middle is for a load of 1 kg. FIG. 15 is a graph showing the transition of the d-axis voltage and the phase error Δθ when the high-speed region determination 2 is not applied in the D section, when the eccentricity amount is small and when the eccentricity amount is large.

In any case, by applying the present invention, the magnitude and degree of change of the phase error Δθ between the phase of the d-axis and the actual phase, or the phase error Δθ and the d-axis voltage Vd are corrected by the load. Since the method of determining the eccentric state by the correlation with the value is used in combination or complemented, the eccentric state can be accurately determined.

Although one embodiment of the present invention has been described above, the specific configuration of each part is not limited to the above-described embodiment.

For example, the procedure shown in the flowcharts of FIGS. 8 and 9 may be performed in the D section, or the procedure shown in the flowcharts of FIGS. 10 and 11 may be performed in the C section.

Further, as a method for estimating the phase error, various methods other than the above can be used.

Other configurations can be variously modified without departing from the spirit of the present invention.

100 ... Eccentricity determination unit A4 ... Dehydration tank M ... Motor Vd ... d-axis voltage Vd _{amd ...} Load amount correction value Δθ ... Phase error between the estimated phase of the d-axis and the actual phase of the d-axis

Claims (4)

In a motor provided with a motor for rotationally driving the dehydration tank and a control means for vector-controlling the torque generated by the motor.
The control means includes an eccentricity determining unit for determining an eccentric state of the dehydration tank.
The eccentricity determination unit is
The case where the first value based on the d-axis voltage generated in performing the vector control is compared with the preset first threshold value and the first value is equal to or higher than the first threshold value. and,
A second value based on the phase error between the phase of the d-axis estimated for performing the vector control and the phase of the actual d-axis is compared with a preset second threshold value, and the second value is obtained. A washing machine characterized in that it is determined that the eccentricity of the dehydration tub is large when the value is equal to or higher than the second threshold value . The first value is
The reference value based on the d-axis voltage generated in performing the vector control when the dehydration tank is rotating at the first rotation speed exceeding the resonance rotation speed, and the dehydration tank is larger than the first rotation speed. The washing machine according to claim 1, wherein the washing machine is a difference from a value based on a d-axis voltage generated when performing the vector control when rotating at the second rotation speed. When the rotation speed of the dehydration tank is in the ultra-high speed rotation range exceeding 1000 rpm,
The eccentricity determination unit is
The first reference value based on the d-axis voltage generated for performing the vector control when the dehydration tank is rotating at a third rotation speed exceeding the resonance rotation speed, and the dehydration tank at the third rotation speed. The first difference from the value based on the d-axis voltage generated in performing the vector control when rotating at a fourth rotation speed larger than that is calculated, and this first difference and a preset third threshold value are calculated. When the first difference is equal to or greater than the third threshold, or
A second reference value based on the phase error between the phase of the d-axis estimated for performing the vector control and the actual phase of the d-axis when the dehydration tank is rotating at a third rotation speed exceeding the resonance rotation speed. Based on the phase error between the phase of the d-axis estimated to perform the vector control and the actual phase of the d-axis when the dehydration tank is rotating at the fourth rotation speed higher than the third rotation speed. The second difference from the above value is calculated, the second difference is compared with the preset fourth threshold value, and when the second difference is equal to or greater than the fourth threshold value, the eccentricity of the dehydration tank is large. The washing machine according to claim 1 or 2, wherein the washing machine is determined to be. The washing machine according to any one of claims 1 to 3, wherein the value of the Fourier coefficient corresponding to the actual frequency among the Fourier series expansions for the waveform of the phase error is used as the phase error.

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