JP2007050114A - Washing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To highly accurately detect an eccentric amount when the water tub of a vertical type washing machine is rotated. <P>SOLUTION: A microcomputer constituting the controller of the washing machine obtains an average value for each prescribed period for a q axis current detected by vector-controlling a motor for rotating a washing tub, and detects the eccentric amount of the water tub in the state that the washing tub is rotated on the basis of the difference of the average values. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes a water tub suspended in an outer box via a plurality of elastic suspension mechanisms, and a washing tub disposed in the water tub and provided with stirring blades therein, and the laundry tub is rotated. It is related with the washing machine which spin-dry | dehydrates the laundry accommodated in the said tank.

The so-called vertical fully automatic washing machine has a water tank suspended in an outer box via a plurality of elastic suspension mechanisms, and a washing tank disposed in the water tank and provided with stirring blades inside. Rotate the stirring blade to wash and rinse, and spin the washing tub at high speed to perform dehydration. In the washing machine having such a configuration, when the laundry is distributed at a high speed when the distribution state of the laundry in the washing tub is unbalanced with respect to the rotation axis, the laundry is caused to rotate on the inner peripheral wall by centrifugal force. There is a problem that the vibrations and noise increase due to sticking and eccentricity.
Conventionally, when rotation in such an eccentric state occurs, the water tank comes into contact with a lever switch installed outside the water tank and the switch is turned on to stop the rotation. However, the state in which the water tub vibrates when the laundry tub rotates may vary depending on the distribution state of the laundry in the laundry tub. In FIG. 10, the typical example of the distribution state of a laundry is shown with the vertical side view of a washing tub.

In FIG. 10, the portions where the laundry is unevenly distributed are indicated by circles with different hatching. (A) is when the laundry is unevenly distributed in a part of the upper part where the laundry is evenly distributed from the bottom of the washing tub (upper unbalanced state), and (b) is the laundry on one side of the bottom of the washing tub Is unevenly distributed (lower unbalanced state), and (c) is the case where laundry is unevenly distributed on one side (upper and lower) of the washing tub (translational unbalanced state). When the washing tub rotates at high speed in these unbalanced states, roll vibration is generated in the water tub. And (d) is a case where the laundry is unevenly distributed in the state facing the upper and lower sides of the washing tub (opposing unbalanced state). When the washing tub rotates at high speed in this unbalanced state, pitch vibration is generated in the water tub.
Among these, when rolling vibration occurs in the cases of FIGS. 10A to 10C, the lateral displacement amount (eccentric amount) of the aquarium is large, so that the aquarium easily hits the lever switch and is easy to detect. is there. However, when longitudinal vibration is generated in the case of FIG. 10D, the lateral displacement of the water tank is small, and the water tank is difficult to detect because it is difficult to hit the lever switch.

By the way, in recent years, techniques for applying vector control to drive motors used in washing machines are becoming widespread (see, for example, Patent Documents 1 and 2). In the vector control, the output torque of the motor can be controlled with high accuracy based on the torque component current (q-axis current), and therefore it is possible to easily detect the longitudinal vibration due to the case of FIG. For example, when the torque component current command is given as a certain value and the motor rotation speed does not increase as expected, it is the result that a part of the motor output is absorbed by the vibration generated in the water tank. Therefore, it can be detected that the amount of eccentricity (vibration) in the rotation state is large.
JP 2001-276468 A JP 2004-49431 A

  In addition, one of the trends in technological development of washing machines is to improve driving efficiency by using a motor with a higher output torque. At present, for example, a rotor using a neodymium magnet with extremely strong magnetic force is used. A high-power motor such as a configured brushless DC motor is used in a washing machine. In that case, even if a part of the output of the motor is absorbed by the generated vibration, it is possible to maintain a high rotational speed, so that the above method has a problem that it is difficult to detect the amount of eccentricity.

Here, Patent Document 1 detects the eccentric amount of the drum by detecting the fluctuation amplitude α of the torque current in one rotation cycle of the drum in the drum type washing machine. However, such a system cannot detect a vibration pattern derived from a structure unique to a vertical washing machine as shown in FIG. Patent Document 2 is also a drum-type washing machine, which integrates a q-axis current by a low-pass filter to perform a square operation and further balances during drum rotation based on a fluctuation range H obtained as a result of passing through the low-pass filter. It is determined whether or not it is appropriate. Similarly to Patent Document 1, this technique cannot detect a vibration pattern unique to a vertical washing machine.
This invention is made | formed in view of the said situation, The objective is to detect the eccentric amount of the water tank generated when a washing tub rotates in what is called a vertical washing machine with higher precision.

The washing machine of the present invention includes a water tub suspended in an outer box via a plurality of elastic suspension mechanisms, and a washing tub disposed in the water tub and provided with stirring blades therein. In what dehydrates the laundry stored in the tank by rotating the
The torque component current detected by vector control of the motor for rotating the washing tub is obtained an average value for each predetermined period, and the eccentricity in the state where the washing tub is rotating based on the difference between the average values. An eccentric amount detecting means for detecting the amount is provided.

  That is, the inventor of the present invention has analyzed in detail the state of the detected torque component current in the case where the washing tub rotates and the pitch vibration of the water tub occurs. As a result, even if the amplitude level of the torque component current was simply evaluated, it was not possible to obtain a level difference that could be clearly detected, but the difference was obtained for the average value of the torque component current for each predetermined period. And when pitch vibration occurred, it was found that the difference was clearly increased. Therefore, the eccentricity detection means can catch the increase in the eccentricity that occurs when the water tank vibrates longitudinally based on the detection principle described above.

  According to the present invention, when a high-output motor is used, it is difficult to detect with the conventional method, the occurrence of pitch vibration of the water tank, which is a phenomenon derived from the unique structure of the so-called vertical washing machine, It becomes possible to detect reliably.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a longitudinal sectional side view showing a part of the vertical fully automatic washing machine. The washing machine body 1 includes a rectangular box-shaped outer box 2 and a hollow top cover 3 provided on the upper surface of the outer box 2. Inside the outer box 2, a water tank 4 is elastically suspended by an elastic suspension mechanism 5 (in reality, only one is shown) including a support shaft 5a and a spring 5b. The washing tub 6 serving as a dehydration tub and washing tub is rotatably arranged. A number of dewatering holes 6 a are formed in the peripheral wall portion of the washing tub 6. A balance ring 7 is provided at the upper end of the washing tub 6. Further, a stirring blade 8 is rotatably disposed at the inner bottom of the washing tub 6.

  A mechanism portion 9 having a tank shaft 9a and a stirring shaft 9b is disposed on the outer bottom of the water tank 4 in the outer box 2, and the washing tub 6 is connected to the tank shaft 9a, and the stirring shaft 9b. The agitating blade 8 is connected to the upper end of the. Moreover, the outer rotor 10a of the washing machine motor 10 which consists of a direct current brushless DC motor is connected with the lower end part of the stirring shaft 9b. In the washing process and the rinsing process, only the agitating blade 8 is rotated forward and backward by the washing machine motor 10, and in the dehydration process, the agitating blade 8 and the washing tub 6 are rotated at high speed synchronously. Yes. As described above, the washing machine motor 10 is a motor with a high output torque configured by arranging a neodymium magnet (not shown) on the inner peripheral side of the rotor 10a.

  A drain port 11 is formed at the bottom of the water tank 4, and a drain hose 13 is connected to the drain port 11 via a drain valve 12. The top cover 3 is provided with a lid 17. An operation panel 18 is provided on the upper surface of the front portion of the top cover 3, and a control device 19 is disposed on the back side thereof.

  FIG. 5 is a functional block diagram showing the configuration of the control-drive system centered on the control device 19. The target speed command ωref is output from a control microcomputer (microcomputer, eccentricity detecting means) 20 that controls the overall operation of the washing machine, and the subtractor 33 receives the target speed command ωref and an estimator 34. The result of subtraction with the rotational speed ω of the motor 10 detected by the above is output. The speed PI control unit 35 performs PI control based on the difference between the target speed command ωref and the detected speed ω, and generates a q-axis current command value Iqref and a d-axis current command value Idref. The subtractors 36 and 37 subtract the results of subtraction between the command values Iqref and Idref and the q-axis current value Iq (torque component current) and d-axis current value Id output from the αβ / dq conversion unit 38 into the current PI control unit 39q. , 39d. The q-axis current value Iq is also given to the microcomputer 20.

The current PI control units 39q and 39d perform PI control based on the difference between the q-axis current command value Iqref and the d-axis current command value Idref, and generate the q-axis voltage command value Vq and the d-axis voltage command value Vd. Output. The dq / αβ conversion unit 40 converts the voltage command values Vd and Vq into voltage command values Vα and Vβ based on the rotation phase angle (rotor position angle) θ of the secondary magnetic flux in the motor 10 detected by the estimator 34. To do.
The αβ / UVW conversion unit 41 converts the voltage command values Vα and Vβ into three-phase voltage command values Vu, Vv, and Vw and outputs them. The changeover switches 42u, 42v, 42w switch between the voltage command values Vu, Vv, Vw and the voltage command values Vus, Vvs, Vws for starting output from the initial pattern output unit 43 and output them.

  The PWM forming unit 44 converts each phase PWM signal Vup (+, −), Vvp (+, −), Vwp (+, −) obtained by modulating a carrier wave of 16 kHz based on the voltage command values Vus, Vvs, Vws into the inverter circuit 45. Output to. The inverter circuit 45 is configured by connecting six IGBTs 46 in a three-phase bridge, and the emitters of the lower arm side U and V phase IGBTs 46 are connected to the ground via current detection shunt resistors 47 (u, v), respectively. Has been. The common connection point between the two is connected to the A / D converter 49 via an amplification / bias circuit (not shown). The inverter circuit 45 is applied with a DC voltage of about 280V obtained by double voltage full-wave rectification of a 100V AC power supply. The amplifier / bias circuit amplifies the terminal voltage of the shunt resistor 47 and applies a bias so that the output range of the amplified signal is within the positive side.

The A / D converter 49 outputs current data Iu and Iv obtained by A / D converting the output signal of the amplifier / bias circuit. The UVW / αβ converter 52 estimates W-phase current data Iw from the current data Iu, Iv, and converts the three-phase current data Iu, Iv, Iw into biaxial current data Iα, Iβ in an orthogonal coordinate system.
The αβ / dq converter 38 obtains the rotor position angle θ of the motor 10 from the estimator 34 during vector control and converts the biaxial current data Iα, Iβ into the d-axis current value Id, the q-axis current value Iq. Output every second. The estimator 34 estimates the position angle θ and the rotational speed ω of the rotor 10b based on the voltage command value Vd and Vq, the d-axis current value Id, and the q-axis current value Iq, and outputs them to each part. In the above configuration, the configuration excluding the inverter circuit 45 is a function mainly realized by software of a DSP (Digital Signal Processor) 53.

  Next, the operation of this embodiment will be described with reference to FIGS. 1 to 3 and FIGS. FIG. 6 shows a control state of the rotational speed of the motor 10 during the dehydrating operation. When the microcomputer 20 increases the rotation speed to N1 rpm, the microcomputer 20 performs roll detection (up / down, translational unbalance detection) of the water tank 4 while maintaining the state (1). Then, while increasing the rotation speed to N3 rpm, (2) detection of pitching of the water tank 4 (opposite unbalance detection) is performed. Finally, (3) contact detection of the water tank 4 with respect to the outer box 2 is performed until the steady rotation speed of the dehydrating operation is increased to, for example, 700 to 800 rpm.

7 to 9 are flowcharts corresponding to the processes performed by the microcomputer 20 in the above (1) to (3).
<(1) Roll detection of water tank 4>
In FIG. 7, the microcomputer 20 accelerates the motor 10, that is, the washing tub 6 so that the rotation speed reaches N1 rpm (steps S <b> 1 and S <b> 2). When the rotational speed reaches N1 rpm (step S2, "YES"), the rotational speed is maintained (fixed) as it is (step S3).

  Next, when the microcomputer 20 measures the temperature with a temperature sensor (not shown) that detects, for example, the outside air temperature, the temperature inside the outer box 2, or the temperature of the water tank 4, according to the temperature, in step S <b> 7. After determining a threshold value used for the determination (step S5), the process proceeds to step S6. The eccentricity measurement here is performed by the process shown in FIG. As shown in FIG. 2A, the q-axis current waveform has a small AC component amplitude when no eccentricity (unbalance) occurs due to rotation of the washing tub 4, and FIGS. 10A to 10C. It has been confirmed that the amplitude of the alternating current component increases when the rolling vibration of the water tank 4 as shown in FIG. Therefore, as shown in FIG. 2B, the DC component of the q-axis current is cut, and an effective value is obtained for the AC component (that is, “eccentricity” = “effective value of the q-axis current AC component”).

  In subsequent step S7, it is determined whether or not the effective value is below the threshold value determined in step S5. If “eccentricity” <“threshold” (“YES”), it is determined that no rolling vibration has occurred in the water tank 4, and the dehydration operation is continued as it is (step S8). On the other hand, if “the amount of eccentricity” ≧ “threshold” (“NO”), it is estimated that the rolling vibration of the water tub 4 is generated, so that the rotation of the washing tub 6 is temporarily stopped, for example. Water is fed into the interior, the agitation blade 8 is agitated to adjust the laundry distribution balance, and a process (correction process) for eliminating the eccentric state is performed (step S9). Note that the resonance point of the rolling vibration is in the vicinity of 100 rpm, and this resonance point is determined mainly by the length of the support rod 5a of the elastic suspension mechanism 5.

<(2) Pitch detection of water tank 4>
The process shown in FIG. 8 is executed following the process shown in FIG. When the microcomputer 20 accelerates the rotation speed of the washing tub 6 so as to reach N2 rpm from N1 rpm, the threshold value to be used for the determination in step S17 is determined based on the measured temperature, similarly to steps S4 and S5. (Steps S11 and S12). Then, acceleration is controlled so that the rotational speed increases at a rate of 10 rpm per second (step S13), and the eccentricity is measured and compared with a threshold value until the rotational speed reaches N3 rpm (step S16, S17).

  Here, the measurement of the amount of eccentricity in step S16 will be described with reference to FIG. FIG. 1 shows a waveform envelope (indicated by a two-dot chain line in the figure) showing a vibration state of the water tank 4 in a process in which the rotation speed of the motor 10 increases from N1 rpm to N3 rpm, and a q-axis current waveform in that case Is shown. The q-axis current waveform is shown for both cases where the longitudinal vibration of the water tank 4 occurs and does not occur.

When the pitch vibration of the water tank 4 does not occur, the q-axis current does not change greatly, but when the pitch vibration occurs, the q-axis current changes gently. Conventionally, in the case of a motor with a commonly used output, when the same vibration is generated, the rotation speed of the motor is reduced. However, in the case of the motor 10 with a high output torque, the motor rotates with the vibration generated. Since the number can be increased, more energy is consumed and the q-axis current is increased.
In this case, the resonance point of longitudinal vibration is in the vicinity of 200 rpm (provided that the ambient temperature is 25 ° C. to 30 ° C.), and this resonance point is dominated by the elasticity of the spring 5b of the elastic suspension mechanism 5. Determined. The peak of the q-axis current also substantially coincides with the resonance point of pitch vibration.

  In step S16, the q-axis current data sampled every 128 μs is thinned out, and an average is obtained for 1000 pieces of data obtained every 1 ms (that is, while the rotation speed increases by 10 rpm). The difference from the calculated average value is calculated. That is, here, “eccentricity” = “difference in average value”. In step S17, it is determined whether or not the difference between the average values is below the threshold value determined in step S12. If “average value difference” <“threshold value” (“YES”), it is determined that no vertical vibration has occurred in the aquarium 4, so the process returns to step S14, where “average value difference” ≧ “ If it is “threshold” (“NO”), it is presumed that the pitching vibration of the water tank 4 has occurred, so the correction process similar to step S9 is executed (step S18).

  Here, the change in the step shape in FIG. 1 indicates a change in the difference of the q-axis current average value calculated every second. The difference value immediately after the vibration of the water tank 4 reaches the peak is the maximum. Therefore, by setting the threshold value so as to detect the case where the difference value reaches the maximum, it is possible to detect the longitudinal vibration of the water tank 4.

As described above, when the rotation speed reaches N3 rpm during the loop of steps S14, S16, and S17 (step S14, “YES”), there is no possibility of occurrence of pitch vibration, and the dehydration operation is continued ( Step S15). Note that the longitudinal vibration is detected in the rotation speed range N2 rpm to N3 rpm. This is the elasticity of the spring 5b of the elastic suspension mechanism 5 according to the temperature change of the environment where the washing machine is installed. This is because there is a possibility that the resonance frequency changes in the above-mentioned range due to the change of.
For example, if the washing machine has a drying function, warm air may be blown into the washing tub 6 even during the dehydration operation (so-called preheat dehydration), so that the internal temperature of the outer box 2 is, for example, 40 ° C. or higher. May rise.

(3) Detection of Contact of Water Tank 4 with Outer Box 2 The process shown in FIG. 9 is executed following the process shown in FIG. Similarly to step S12, the microcomputer 20 determines a threshold value used for the determination in step S22 (step S20). However, here, when the water tank 4 comes into contact with the outer box 2, the change of the q-axis current becomes extremely large, so the threshold value is set based on the measured temperature as in the cases (1) and (2). There is no need to change.

  Then, when the effective value of the q-axis current is calculated in the same manner as in step S6 shown in FIG. 7 (step S21), in subsequent step S22, it is determined whether or not the effective value is lower than the threshold value determined in step S20. judge. If “effective value” <“threshold” (“YES”), it is determined that no contact (per outer box) of the water tank 4 with the outer box 2 has occurred, so the dehydration operation is not completed ( Step S23, "NO") Return to step S21. That is, here, “eccentricity” = “effective value”. On the other hand, if “effective value” ≧ “threshold value” (“NO”), it is presumed that the water tank 4 is in contact with the outer box 2, so the dehydration operation is stopped and the same as step S 18. The correction process is executed (step S24).

Here, in FIG. 3, the current waveform when the water tank 4 contacts the outer case 2 is shown. FIG. 3A is a diagram corresponding to FIG. 6 and shows the measured value of the rotational speed. When the rotation speed of the washing tub 6 reaches 700 rpm or more, which is near the steady rotation speed of the dehydration operation, the water tub 4 is in contact with the outer box 2. FIG. 3B shows the q-axis current waveform at that time, and the amplitude of the q-axis current is increased. FIG. 3C shows the effective value of the q-axis current at that time, and the effective value shows a clearer increasing tendency. Therefore, by setting the threshold value so as to detect the case where the effective value increases in this way, it is possible to detect the contact of the water tank 4 with the outer box 2.
In FIGS. 3B and 3C, the current waveform before the outer box hit is omitted for the convenience of the applicant.

  As described above, according to this embodiment, the microcomputer 20 of the control device 19 sets the effective value of the q-axis current amplitude detected by vector control of the motor 10 that rotates the washing tub 6 to a predetermined threshold value. By exceeding, when the washing tub 6 rotates, it is detected that rolling vibration has occurred in the water tub 4, and an average value for a predetermined period is obtained for the q-axis current, and based on the difference between the average values, The amount of eccentricity is detected when longitudinal vibration is generated in the water tub 4 while the washing tub 6 is rotating. Therefore, when the high-power motor 10 is used, it is possible to reliably detect the occurrence of the vertical vibration of the water tank 4, which is a unique phenomenon derived from the structure of the vertical washing machine, which is difficult to detect with the conventional method. Therefore, it is possible to provide a washing machine that can be operated with lower vibration and lower noise.

  Since the microcomputer 20 detects the amount of eccentricity at N2 rpm to N3 rpm, which is in the vicinity of the resonance point when the water tank 4 vibrates longitudinally, even if the resonance point changes according to the ambient temperature, the pitch vibration is reliably detected. Can be detected. Further, the microcomputer 20 allows the water tub 4 to move to the outer box 2 when the washing tub 6 rotates by the effective value of the q-axis current amplitude exceeding a predetermined threshold (greater than the above threshold). When the contact state is detected and the contact is detected, the rotation of the washing tub 6 is stopped, so that the mechanism of the washing machine can be protected.

The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following modifications are possible.
The number of rotations of the washing tub corresponding to the resonance point when the water tub vibrates is an example, and an appropriate value may be set according to the individual design.
The sampling interval of the q-axis current, the predetermined period when obtaining the average value, the number of samples, etc. may be changed as appropriate.

The figure which is one Example of this invention, and shows the waveform which shows the vibration state of the water tank in the process in which the rotation speed of a motor raises from N1 rpm to N3 rpm, and the q-axis current waveform in that case (A) is a q-axis current waveform when roll vibration is generated, and (b) is a diagram showing a process for obtaining an effective value of the q-axis current waveform amplitude. FIG. 6 shows a current waveform when the water tank is in contact with the outer box, where (a) shows an actual rotation speed corresponding to FIG. 6, (b) shows a q-axis current waveform, and (c) shows an effective value of the q-axis current. Figure Longitudinal side view showing a partially broken vertical automatic washing machine Functional block diagram showing the configuration of the control-drive system centering on the control device Indicates the control state of the motor speed during dehydration operation Flow chart showing the contents of the tank tank roll detection process Flow chart showing the contents of the pitch detection process Flow chart showing the contents of the contact detection process for the water tank outer box The typical example of the unbalance distribution state of the laundry is shown, (a) is an upper unbalancing state, (b) is a lower unbalancing state, (c) is a translational unbalancing state, (d) is a diagram showing an opposing unbalancing state.

Explanation of symbols

  In the drawings, 2 is an outer box, 4 is a water tank, 5 is an elastic suspension mechanism, 6 is a washing tub, 8 is a stirring blade, 10 is a motor, and 20 is a microcomputer (eccentricity detecting means).

Claims (3)

A water tub suspended in the outer box via a plurality of elastic suspension mechanisms, and a washing tub disposed in the water tub and provided with stirring blades therein, and rotating the washing tub In the washing machine for dehydrating the laundry contained therein,
The torque component current detected by vector control of the motor for rotating the washing tub is obtained an average value for each predetermined period, and the eccentricity in the state where the washing tub is rotating based on the difference between the average values. A washing machine comprising an eccentric amount detecting means for detecting the amount.   The washing machine according to claim 1, wherein the eccentricity detecting means detects the eccentricity in the vicinity of a resonance point when the water tank vibrates longitudinally. The eccentricity detection means detects a state where the water tub contacts the outer case side when the effective value of the amplitude of the torque component current exceeds a predetermined threshold value and the washing tub rotates.
The washing machine according to claim 1 or 2, wherein when the contact is detected, the washing tub is controlled to stop rotating.

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