JP2003053092A - Washing machine - Google Patents

Abstract

(57) [Problem] To provide a washing machine capable of further suppressing noise and vibration by performing motor torque control with higher accuracy. SOLUTION: A motor 2 for generating a rotational driving force for performing a washing, rinsing and dehydrating operation in a fully automatic washing machine.
4 is detected by the shunt resistors 39u and 39v arranged on the emitter side of the IGBTs 38d and 38f on the arm side constituting the inverter circuit 37, and the motor 24 is controlled by the DSP 45 by the DSP 45 based on the detected currents Iu and Iv. By performing vector control in seconds, the generated torque is controlled so as to be optimal for each of the washing, rinsing operation and dehydration operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a washing machine provided with control means for controlling torque of a motor for generating a rotational driving force for washing, rinsing and dehydrating operations.

[0002]

2. Description of the Related Art Conventionally, in a fully automatic washing machine,
Stirrer blade (pulsator) for rinsing operation and dehydration operation
Alternatively, a method in which a brushless DC motor is used as a motor for rotating the rotary tank and the brushless DC motor is driven by an inverter circuit is widely adopted. When the torque is controlled according to the driving conditions of the motor, the voltage applied to the motor is increased or decreased.

FIG. 21 shows a structural example of a control system for a washing machine motor. The control system is composed of, for example, a microcomputer, and as the functional blocks,
A PI control unit 1, a washing pattern output unit 2, a UVW conversion unit 3, an initial pattern output unit 4, a PWM formation unit 5, a position detection unit 6 and the like are provided.

PW of each phase output from the PWM forming section 5
The M signal is output to the inverter circuit 8 that drives the motor 7. A hall sensor 9 for detecting the position of the rotor is incorporated in the motor 7, and the hall sensor 9 detects the position of two phases (U, V) of the three phases and outputs the position detection signal. It is adapted to output to the position detector 6.

The PI control unit 1 outputs a target speed command ωref for a dehydration operation, which is output from a control unit (not shown) that controls the operation of the washing machine, and a motor 7 output from the position detection unit 6.
Based on the detected speed ω of the motor, the rotational speed of the motor 7 is PI-controlled, and the duty command and the phase command of the PWM signal are UV controlled.
Output to the W conversion unit 3. Also, wash pattern output unit 2
Outputs the duty command and the phase command during the washing operation to the UVW conversion unit 3 instead of the PI control unit 1.

The UVW conversion unit 3 converts the command output from the PI control unit 1 or the wash pattern output unit 2 into a voltage command for each phase of U, V, W and outputs it to the PWM formation unit 5. Further, the initial pattern output unit 4 outputs the 120-degree energization pattern to the inverter circuit 8 instead of the UVW conversion unit 3 when the motor 7 is started from the stopped state.

[0007]

However, such a conventional control system has the following problems. That is, the rotation speed of the motor 7 is proportional to the generated torque, but when the applied voltage is controlled as in the above configuration, the generated torque is not proportional to the voltage. Therefore, there is a difference between the target speed command ωref and the detected speed ω of the motor 7. Is likely to occur and control tends to be unstable. Also, the speed fluctuation of the motor 7 becomes large during the washing operation (for example, 0.2 seconds from 0 to 150 rpm).
The PI control could not be applied, and it was necessary to switch to the wash pattern output unit 2.

Further, in the inverter circuit 8, the IGBT
When switching switching elements such as
In order to prevent a short-circuit current from flowing due to the elements on the upper arm side and the elements on the lower arm side turning on at the same time, a so-called dead time should be provided during which both elements are turned off at the same time when the switching state is switched. I have to.
Therefore, the current waveform output from the inverter circuit 8 to each phase winding of the motor 7 becomes a waveform modulated by providing the dead time.

Since it is necessary to secure a minimum time for this dead time, the higher the carrier frequency of PWM modulation is set, the greater the influence on the output current waveform becomes. For example, if the dead time of 3 μs is secured, the total of the ON time and the OFF time is 6 μs, but the ratio when the PWM modulation carrier frequency is 5 kHz (cycle 200 ms) is 3%, and the carrier frequency is 16 kHz ( The ratio when the period is 62.5 μs) is 10%. Generally, in a washing machine, the carrier frequency is often set to 10 kHz or higher in order to suppress the PWM modulated wave from generating audible noise, and it is difficult to avoid that the dead time has a large influence on the output current waveform.

That is, the modulation due to the dead time distorts the output voltage of the inverter circuit 8 and distorts the output current waveform, and the distortion causes fluctuation in the generated torque. Therefore, cogging torque is generated as the motor 7 rotates,
There was a problem of causing noise and vibration.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a washing machine capable of further suppressing the generation of noise and vibration by more accurately controlling the torque of a motor. To do.

[0012]

In order to achieve the above object, a washing machine according to a first aspect of the present invention includes a motor for generating a rotational driving force for washing, rinsing and dehydrating operations, and a current flowing through the motor. Vector control of the motor based on the current detection means for detection and the current detected by the current detection means controls the generated torque of the motor to be optimal at least for each of the washing operation and the dehydration operation. And a torque control means for controlling.

That is, when the torque control means performs vector control, the torque of the motor can be directly controlled in proportion to the q-axis current. Therefore, the responsiveness can be improved as compared with the conventional motor control, and noise and vibration can be reduced.

In this case, as described in claim 2, an inverter circuit for driving the motor is provided, and the current detecting means is connected in series with the switching element on the lower arm side forming the inverter circuit. It is preferable to configure so as to detect the current flowing through. That is, the current flowing through the motor can be detected with an inexpensive configuration without using an expensive current sensor such as a current transformer.

According to a third aspect of the present invention, the motor has a three-phase structure, and the current detecting means is configured to supply the current for two phases out of the three phases whose phase voltage does not show the maximum level, based on the conduction electrical angle. It is preferable that the detection is performed. That is,
When the motor has a three-phase structure, the remaining one phase can be estimated by detecting the currents of the two phases.

By the way, in order to detect the current, it is necessary to turn on the switching element on the lower arm side to flow the phase current through the resistor. Therefore, if an attempt is made to detect a current in a phase in which the phase voltage has the maximum level among the three phases, the maximum value of the phase voltage is reduced. When the driving voltage of the motor is lowered in this way, the current flowing through the winding increases, so that resistance loss increases and efficiency deteriorates.
Therefore, if the current is detected for the two phases of the three phases where the phase voltage does not show the maximum level, the maximum value of the phase voltage is not limited, and the efficiency of the motor is improved.

Further, as described in claim 4, a series circuit is constituted by a plurality of resistors connected in series with the switching element on the lower arm side, and the current detecting means is provided with the series circuit according to a load condition. It is preferable to configure so that the detection position at is switched. With this configuration, for example, when the current is small, the terminal voltage of a plurality of resistors is detected, and when the current is large, the terminal voltage of one resistor is detected, so that the current detection range can be improved. Can be widely used.

In the above case, as described in claim 5, in the preceding stage of the torque control means, the speed of the motor is determined based on the speed command and the rotation speed of the motor obtained from the current detected by the current detection means. It is preferable to provide a speed control means for performing PI control on the. According to this structure, a predetermined rotation speed can be obtained even if the load of the motor changes, so that the cleaning power can be stabilized.

Further, as described in claim 6, the speed control means is configured to output the q-axis and d-axis current command values to the torque control means, and the torque control means is constituted by the q-axis and the q-axis. PI control is performed based on the d-axis current command value and the q-axis and d-axis current values of the motor obtained from the current detected by the current detection means, and the q-axis and d-axis voltage command values are generated. Good to do. According to this structure, it is possible to appropriately obtain the torque required to obtain the predetermined rotation speed.

Further, as described in claim 7, the speed control means may be configured to change the control gain used for the PI control according to the rotation speed of the motor. For example,
When the rotation speed of the motor reaches near the natural frequency of the vibration system centered on the rotating tank, the value of the control gain is set to be larger so that the PI control acts more strongly. Can be effectively suppressed.

In this case, as described in claim 8, the speed control means may be configured to change the control gain used for the PI control at least in each of the washing operation and the dehydration operation. That is, since the driving conditions of the motor greatly differ between the washing operation and the dehydration operation, the vibration can be effectively suppressed by setting the control gain to an appropriate value according to each driving condition.

Further, as described in claim 9, it is preferable that the control cycle in the speed control means is set within 50 m (millisecond) seconds. According to this structure, it is possible to effectively suppress a vibration component having a short cycle that is likely to occur during operation.

Then, as described in claim 10, the torque control means may be configured to start the control at the time when the rotation speed of the motor rises to a predetermined speed. That is, in the region where the rotation speed is low, the detected value of the current by the current detecting means becomes small, so that it becomes difficult to perform the vector control accurately. Therefore, with the above configuration, vector control can be stably performed.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment in which the present invention is applied to a vertical type fully automatic washing machine will now be described with reference to FIGS.
Will be described with reference to. First, FIG. 3 shows a fully automatic washing machine 11
FIG. 3 is a vertical sectional view showing the overall configuration of That is, in the outer box 12 having a rectangular shape as a whole, the water receiving tanks 13 are elastically supported via four sets (only one set is shown) of the vibration isolation mechanisms 14. In this case, the vibration isolation mechanism 14 includes a suspension rod 14a whose upper end is locked upward in the outer box 12 and a vibration damping damper 14b attached to the other end of the suspension rod 14a. Has been done. Anti-vibration mechanism 1
The water receiving tub 13 is elastically supported via 4 to prevent the vibration generated during the washing operation from being transmitted to the outer case 12 as much as possible.

Inside the water receiving tank 13, there is provided a rotating tank 15 serving as a washing tank and a dehydrating tank, and an agitator (pulsator) 16 is provided at the inner bottom portion of the rotating tank 15. .
The rotary tank 15 includes a tank body 15a and the tank body 15a.
The inner cylinder 15b is provided inside and the balance ring 15c is provided at the upper end of the inner cylinder 15b.
Then, when the rotating tank 15 is rotated, the water inside is pumped up by the rotating centrifugal force and the dehydration hole 1 in the upper part of the tank body 15a.
5d is discharged into the water receiving tank 13.

A water passage 17 is provided at the bottom of the rotary tank 15.
Is formed, and this water passage 17 has a drainage passage 17a.
Through the drainage port 18. A drainage channel 20 having a drainage valve 19 is connected to the drainage port 18. Therefore, the rotary tank 15 with the drain valve 19 closed
When water is supplied into the rotary tank 15, water is stored in the rotary tank 15. When the drain valve 19 is opened, the water in the rotary tank 15 is drained.
a, the drainage port 18 and the drainage channel 20.

An auxiliary drain port 18a is provided at the bottom of the water receiving tank 13.
This auxiliary drainage port 18a is connected to the drainage channel 20 by bypassing the drainage valve 19 via a connecting hose (not shown). The water discharged into 13 is discharged.

A mechanism housing 21 is attached to the outer bottom of the water receiving tank 13, and a hollow tank shaft 22 is rotatably provided on the mechanism housing 21. Is connected to the rotary tank 15.
A stirring shaft 23 is rotatably provided inside the tank shaft 22, and the stirring body 1 is provided at the upper end of the stirring shaft 23.
6 are connected. The lower end of the stirring shaft 23 is
Outer rotor type brushless motor 24 as a motor
Is connected to the rotor 24a. The brushless motor 24 directly drives the stirring member 16 in forward and reverse directions during washing.

Further, the brushless motor 24 directly drives the rotary tank 15 and the stirring body 16 in one direction while the tank shaft 12 and the stirring shaft 13 are connected by a clutch (not shown) at the time of dehydration. ing. Therefore, in this embodiment, the so-called direct drive system is adopted in which the rotation speed of the brushless motor 24 is the same as that of the stirring body 16 during washing and the same as that of the rotary tank 15 and the stirring body 16 during dehydration. There is.

FIG. 1 is a functional block diagram showing the configuration of the control system of the washing machine 11. In addition, in FIG. 1, (α, β)
Indicates a Cartesian coordinate diameter obtained by orthogonally transforming a three-phase (UVW) coordinate system corresponding to each phase of the three-phase brushless motor 24 at an electrical angle of 120 degrees, and (d, q) indicates a brushless motor 24.
2 shows the coordinate system of the secondary magnetic flux rotating with the rotation of the rotor 24a.

To the subtractor 25, the target speed command ωref is given as a subtracted value, and the detected speed ω of the brushless motor 24 detected by the estimator 26 is given as a subtracted value. The target speed command ωref is output from a control microcomputer 46 that controls the overall operation of the washing machine 11. The subtraction result of the subtracter 25 is given to the speed PI control unit 27.

The speed PI control unit 27 determines the target speed command ωre
PI control is performed based on the amount of difference between f and the detected speed ω,
The q-axis current command value Iqref and the d-axis current command value Idref are generated and output to the subtracters 28 and 29 as subtracted values, respectively.
The d-axis current command value Idr during washing or rinsing operation
ef is set to "0", and the d-axis current command value Idref is set to a predetermined value for performing the field weakening control during the dehydration operation. The q-axis current value Iq and the d-axis current value Id output from the αβ / dq conversion unit 30 are given to the subtractors 28 and 29 as subtraction values, respectively, and the subtraction results are the current PI control units 31q and 31d. Are given to each.

The current PI control units 31q and 31d perform PI control based on the difference amount between the q-axis current command value Iqref and the d-axis current command value Idref, and the q-axis voltage command value Vq and the d-axis voltage command value Vd. Is generated and output to the dq / αβ conversion unit 32. The dq / αβ converter 32 is given the rotational phase angle (rotor position angle) θ of the secondary magnetic flux in the brushless motor 24 detected by the estimator 26,
The voltage command values Vd and Vq are converted into voltage command values Vα and Vβ based on the rotation phase angle θ.

The voltage command values Vα and Vβ output from the dq / αβ converter 32 are provided to the αβ / UVW converter 33. The αβ / UVW conversion unit 33 determines the voltage command values Vα, V
β is converted into three-phase voltage command values Vu, Vv, Vw and output. The voltage command values Vu, Vv, Vw are fixed contacts 34ua, 3 of one of the changeover switches 34u, 34v, 34w.
4 va, 34 wa and the other fixed contact 3
4ub, 34vb, and 34wb are voltage command values Vus and Vv for activation output by the initial pattern output unit 35.
s and Vws are given. And the changeover switch 3
4u, 34v, 34w movable contacts 34uc, 34vc,
34wc is connected to the input terminal of the PWM forming unit 36.

The PWM forming section 36 controls the voltage command values Vus, V
PWM signal Vup (+,-), Vvp (+,-), Vwp of each phase obtained by modulating a carrier wave (triangular wave) of 16 kHz based on vs, Vws
(+,-) Is output to the inverter circuit 37. The PWM signals Vup to Vwp are, for example, signals having pulse widths corresponding to voltage amplitudes based on a sine wave so that sinusoidal currents are supplied to the phase windings 24u, 24v, 24w (see FIG. 2) of the motor 24. Is output as.

The inverter circuit 37 includes, as shown in FIG. 2, six IGBTs (switching elements) 38a to 38a.
f is configured by a three-phase bridge connection, and the emitters of the IGBTs 38d, 38e on the lower arm side are connected to the ground via shunt resistors (current detection means) 39u, 39v for current detection, respectively. Further, the common connection point of both is connected via the amplification / bias circuits 40u and 40v as shown in FIG.
It is connected to the A / D conversion section (current detection means) 41 shown in FIG. The resistance value of the shunt resistor 39 is about 0.1Ω.

The amplification / bias circuit 40 is configured to include an operational amplifier and the like, and amplifies the terminal voltage of the shunt resistor 39 and biases the amplified signal so that the output range of the amplified signal is within the positive side (for example, 0 to +5 V). To give. Further, the amplification / bias circuits 40u, 40
The output terminal of v is commonly connected to the input terminal of the overcurrent detection unit 43 via the diodes 42u and 42v.

When the overcurrent detection unit 43 refers to the output signal levels of the amplification / bias circuits 40u and 40v and detects that an overcurrent has flown into either phase, it outputs an overcurrent detection signal to the control unit 47 (control). Microcomputer 46 and DSP 45 described later
To the motor 2 by the inverter circuit 37
The driving of No. 4 is stopped. Note that the W-phase current can be indirectly estimated based on the U- and V-phase currents.

The inverter circuit 37 has a voltage of 100V.
The AC power supply 48 of the full wave rectifier circuit 49 composed of a diode bridge and the two capacitors 5 connected in series.
A DC voltage of about 280 V, which has been double-wave full-wave rectified by 0a and 50b, is applied.

Referring again to FIG. 1, the A / D converter 41
Is the output signal of the amplification / bias circuit 40u, 40v
The / D converted current data Iu and Iv are output to the UVW / αβ converter 44. The UVW / αβ converter 44 estimates the W-phase current data Iw from the current data Iu, Iv, and converts the three-phase current data Iu, Iv, Iw into the biaxial current data Iα, in the orthogonal coordinate system according to the equation (1). Convert to Iβ.

[Equation 1] Then, the biaxial current data Iα and Iβ are output to the αβ / dq conversion unit 30.

The αβ / dq conversion unit 30 obtains the rotor position angle θ of the motor 24 from the estimator 26 during vector control, so that the biaxial current data I can be obtained according to the equation (2).
α and Iβ are d-axis current values Id on the rotating coordinate system (d, q),
Convert to q-axis current value Iq.

[Equation 2] The d-axis current value Id and the q-axis current value Iq are output to the estimator 26 and the subtractors 28 and 29 as described above.

The estimator 26 determines the d-axis current value Id,
The position angle θ and the rotation speed ω of the rotor 24a are estimated based on the q-axis current value Iq and output to each unit. Where motor 2
In the case of No. 4, at the time of start-up, direct current excitation is performed by the initial pattern output unit 35 to initialize the rotational position of the rotor 24a, and then the start-up pattern is applied and forced commutation is performed. At the time of forced commutation due to the application of this starting pattern, the position angle θ is clear without needing to be estimated. And αβ
The / dq conversion unit 30 determines the position angle θin obtained from the initial pattern output unit 35 immediately before the vector control is started.
Using it as an initial value, the current values Id and Iq are calculated and output.

After the vector control is started, the estimator 26 is activated to estimate the rotor 24a position angle θ and the rotation speed ω. In this case, the estimator 26 is αβ
Assuming that the rotor position angle θn output to the / dq converter 30 is the estimator 26, the estimator 26 calculates the rotor position angle θn-1 estimated by vector operation based on the current values Id and Iq and the rotor position angle estimated one cycle before. The rotor position angle θn is estimated based on the correlation with θn-2.

In the above configuration, the configuration excluding the inverter circuit 37, the amplification / bias circuit 40, the diode 42, and the overcurrent detection unit 43 is mainly a DSP (Digital Si).
gnalProcessor, torque control means) 45 software. And speed PI
The speed control cycle by the control unit 27 is set to be 1 msec or less. The control microcomputer 46 performs the vector control and gives the target speed command ωref to the DSP 45.

Further, in the present embodiment, when the motor 24 is started, as will be described later, the PI control similar to the conventional configuration is temporarily performed before the start of the vector control. Therefore, the PI controller 1, UV having the configuration shown in FIG.
The W conversion unit 3 is provided in parallel, and in reality, the voltage commands Vu, Vv, and Vw output from the UVW conversion unit 3 are also switched by the changeover switch 34 to change the PWM formation unit 3.
6 can be output.

Next, the operation of this embodiment will be described with reference to FIGS. 4 to 12. FIG. 4 is a flowchart mainly showing the schematic control contents by the control microcomputer 46. The control microcomputer 46 performs the above-described start-up process, for example, when starting the washing operation (step S1).
That is, the movable contacts 34u of the changeover switches 34u to 34w.
c to 34wc are connected to the fixed contacts 34ub to 34wb to perform DC excitation by the initial pattern output unit 35 to initialize the rotational position of the rotor 24a, and then the voltage command value Vus.
~ Vws is applied to the inverter circuit 37 to forcibly commutate the motor 24 (step S2). Then, the motor 24 starts rotating and the rotation speed gradually increases.

Then, when the control microcomputer 46 determines that the number of rotations of the motor 24 has reached 20 rpm by the detection signal provided by the initial pattern output unit 35 (step S3, "YES"), the changeover switches 34u ... The movable contacts 34uc to 34wc of 34w are switched to be connected to the fixed contacts 34ua to 34wa, output of the target speed command ωref is started, and voltage control (PI control) by the same configuration as the conventional one is performed (step S).
4). That is, it is difficult to perform vector control with high accuracy in a region where the rotation speed is relatively low.

Subsequently, the control microcomputer 46 refers to the rotation speed ω given from the estimator 26 and determines that the number of rotations of the motor 24 has reached 60 rpm (step S5, "YES"), and performs vector control. It is started (step S6). After that, the operation is continued until an instruction to stop the operation is given (step S7).

The flow of processing for the vector control after step S6 will be described below. PWM forming unit 36
Generates a PWM carrier wave of 16 kHz by the counter output of an internal up / down counter (not shown), and when the counter value reaches "0", that is, the valley of the triangular wave, the conversion timing signal is A / D. The data is output to the conversion unit 41 (see FIG. 5).

As shown in FIG. 5, the PWM forming section 36 is
Voltage command values Vu to V output by the αβ / UVW converter 33
By comparing the levels of w and the PWM carrier wave, the IGBT 38 on the upper arm side during the period when the latter level exceeds the former level.
PWM signals Vup (+) to Vwp so that a to 38c are turned on.
Output (+). Then, the IGBT 38d on the lower arm side
Up to 38f are turned on with a dead time in between while the upper arm IGBTs 38a to 38c are off.

FIG. 6 is a waveform diagram showing the relationship between the inversion IMINV of the phase current of the motor 24, the current ISR flowing through the shunt resistor 39, and the phase voltage. That is, the period in which the current ISR flows is a case where the IGBT 38 on the lower arm side is turned on and the phase voltage shows 0V. Therefore, the valley of the triangular wave indicates the intermediate phase during the period when the lower arm side IGBTs 38d to 38f are on. That is, the A / D converter 41
However, if the A / D conversion is performed at the time when the counter value inside the PWM forming unit 36 is “0”, the phase current flowing through the lower arm side of the inverter circuit 37 can be reliably sampled.

The current values Iu and Iv A / D converted by the A / D converter 41 are UV together with the estimated current value Iw.
The two-axis current data Iα, Iβ, → Id, Iq are converted through the W / αβ conversion unit 44 and the αβ / dq conversion unit 30 and output to the estimator 26 and the subtractors 28, 29, and the estimator 26 The position angle θ and the rotation speed ω are estimated by. The current Iq is a current flowing in a direction perpendicular to the direction of the secondary magnetic flux of the motor 24,
It is a current component that contributes to the generation of torque. On the other hand, the current I
d is a current that flows in a direction that is horizontal to the direction of the secondary magnetic flux, and is a current component that does not contribute to the generation of torque.

Then, the speed PI controller 27 determines the q-axis and d-axis current command values Iqre based on the difference between the target speed command ωref and the detected speed ω given by the control microcomputer 46.
f and Idref are output, and current PI control units 31q and 31d
Are the command values Iqref, Idref and the detected current values Iq, I
The voltage command values Vq and Vd are output based on the difference from d.

The voltage command values Vq and Vd are passed through the dq / αβ converter 32 and the αβ / UVW converter 33 to obtain the voltage command values Vq.
u, Vv, and Vw are converted and output to the PWM forming unit 36, and the PWM forming unit 36 outputs the PWM signals Vup to Vwp to the inverter circuit 37. Then, the phase windings 24u to 24w of the motor 24 are energized.

Here, in FIG. 7, the rotary tank 15 is set to 250 rp.
It shows a state in which the rotation speed fluctuates when rotated at m. (a) shows the case of the configuration of this embodiment, (b)
Shows the case of the conventional configuration. The diametrical direction of the circle represents the magnitude of the rotational speed (± 3 rpm around 250 rpm), and the circumferential direction represents the rotational position of the rotary tank 15. still,
A 16 kg weight is placed in the rotary tub 15 as a load equivalent to (laundry + water). Also, the rotary tank 15
Fluid balancers of 400 g and 300 g are arranged at the upper end and the lower end, respectively.

In the case of the conventional structure shown in FIG. 7 (b), the rotation fluctuation has a periodicity linked to the rotation angle, and the rotation fluctuation is generated so as to be largely biased at a specific rotation position (maximum). The fluctuation difference is about 6 rpm). On the other hand, FIG.
In the case of the configuration of the present embodiment shown in (a), the rotation speed is about 250 rpm over the entire rotation position (the maximum fluctuation difference is about 1 rpm). That is, it is apparent that the rotation fluctuation is effectively suppressed by the configuration of this embodiment.

8 and 9 show the shaking amount (displacement amount) of the rotary tank 15 at the start of the dehydration operation in the structure of this embodiment and the conventional structure. In the case of this embodiment shown in FIG.
As compared with the case of the conventional configuration shown in FIG. 9, the peak of the fluctuation amount having a small level occurs at an early time and converges rapidly. That is, since the fluctuation of the rotation speed is reduced, it is possible to suppress the vibration generated during operation. Further, FIG. 10 shows a comparison of noise levels generated by the conventional configuration and the configuration of the present embodiment. With the configuration of this embodiment, the noise level is reduced by about 2 dB at the maximum.

In addition, FIG. 11 shows the target speed command ωref and the rotation speed ω of the motor 24 during the washing operation in the configuration of this embodiment, and FIG. 12 outputs the PI control unit 1 in the conventional configuration. The duty command Duty and the rotation speed ω of the motor 7 are shown. As you can see from these figures,
In the case of the present embodiment, the follow-up of the rotation speed ω with respect to the target speed command ωref is good, and the rotation fluctuation is small and stable.

As described above, according to this embodiment, the current flowing through the motor 24 for generating the rotational driving force for performing the washing, rinsing and dehydrating operations in the fully automatic washing machine 11 is
IGBT 38 on the arm side that constitutes the inverter circuit 37
Shunt resistor 39 placed on the emitter side of d and 38f
u, 39v, vector control of the motor 24 by the DSP 45 based on the detected currents Iu, Iv and speed control with a control cycle of 1 msec, the generated torque is optimal for washing, rinsing operation and dehydration operation. The control is performed so that

That is, since the torque of the motor 24 can be directly controlled in proportion to the q-axis current by the vector control, the responsiveness is improved as compared with the conventional control method and the vibration component with a short cycle which is generated during the operation is generated. Can be effectively suppressed, and noise and vibration can be effectively reduced.
Therefore, the outer box of the washing machine 11 can be formed in a small size, and the useless driving force of the motor 24 can be reduced to obtain an energy saving effect, so that the washing power can be improved.

Further, the current detection is performed by the shunt resistors 39u, 3u.
Since 9v is used, the current flowing through the motor can be detected with an inexpensive structure without using an expensive current sensor such as a current transformer. Since the current of any two phases (U, V) of the three phases is detected and the current of the remaining one phase is obtained by estimation, the configuration can be simplified.

Further, according to this embodiment, the target speed command ωref is set by the speed PI control unit 27 before the dq / αβ conversion unit 32 that substantially controls the torque inside the DSP 45.
Since the speed of the motor 24 is PI-controlled based on the rotation speed ω and the rotation speed ω, a predetermined rotation speed can be obtained even if the load of the motor 24 changes, and the cleaning power can be stabilized.
Then, the current PI control units 31q and 31d also perform PI control on the current and output the q-axis and d-axis voltage command values Vq and Vd to the dq / αβ conversion unit 32, so that a predetermined rotation speed is obtained. It is possible to properly obtain the required torque. Further, according to the present embodiment, the vector control is started from the time when the rotation speed of the motor 24 increases to 60 rpm, so that the vector control can be stably performed with high accuracy.

In addition, the amplification / bias circuits 40u, 40
When the overcurrent detection unit 43 arranged on the output side of v detects the overcurrent flowing through the windings 24u to 24w of the motor 24, it outputs a detection signal to the control microcomputer 46 to stop the drive control of the motor 24. Therefore, even if a short circuit occurs in at least one phase of the motor 24, overcurrent can be detected and safety can be improved.

FIGS. 13 to 16 show the second embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. Only different parts will be described below. In the configuration of the second embodiment, a shunt resistor 39w for W phase and an amplification / bias circuit 40w are added for current detection, and current detection is performed for all three phases. Further, the diodes 42u and 42v are removed, and the overcurrent detection unit 43 has three (4) corresponding to each phase.
3u, 43v, 43w). The output terminals of these three overcurrent detection units 43u, 43v, 43w are commonly connected, and connected to the input port of the control unit 47A.

In this case, for example, the overcurrent detection signal is set to low active, and the overcurrent detection units 43u, 43v, 43w are set.
The output part of has an open drain configuration. Also,
A / D conversion section (current detection means) 41A of the control section 47A
14 has converters 41A (1) and 41A (2) for two channels inside, as shown in FIG. 14, and switches and connects these two channels to three-phase current input so as to correspond. Is configured. Converter 41
Switching between A (1) and 41A (2) is performed by the PWM forming unit 36.
This is performed based on the energization phase angle (electrical angle) of the PWM signal output from Other configurations are similar to those of the first embodiment.

Next, the operation of the second embodiment will be described with reference to FIGS. 15 and 16. FIG. 15 shows a motor 24
When the two-phase modulated wave is energized, the phase voltages Vmu, Vmv, Vmw appearing in each phase winding and the detection timing of each phase current in the A / D converter 41A are shown. For example, the phase section from the electrical angle (π / 6) to (5π / 6) is a section in which the U-phase voltage becomes higher than the V- and W-phase voltages and shows the maximum level, and in this section, the converters 41A (1), 41A.
The V and W phase currents are detected by (2). That is, V, W
Current detection is performed at the timing when the lower arm side IGBTs 39e and 39f of the phase are turned on.

From the subsequent electrical angle (5π / 6) to (3π
The phase section of / 2) is a section in which the V-phase voltage becomes higher than the U-phase and W-phase voltages, and the converter 41A is in that section.
(1), 41A (2) to detect the U, W phase current,
The phase section from the electrical angle (3π / 2) to (2π + π / 6) is a section in which the W-phase voltage is higher than the U- and V-phase voltages, and switching is performed so as to detect the U- and V-phase currents in the section. .

That is, in order to detect the current, it is necessary to turn on the IGBT 38 on the lower arm side to flow the phase current through the resistor 39. Therefore, if an attempt is made to detect a current in a phase in which the phase voltage has the maximum level among the three phases, the maximum value of the phase voltage is reduced, and the current flowing through the winding of the motor 24 increases, so that the resistance loss increases. It will reduce efficiency. FIG. 16 shows the relationship between the maximum output voltage (phase voltage) of the motor 24 and the power consumption.

For example, in the case of detecting the current for the phase showing the maximum level, when the drive voltage of the inverter circuit 37 is about 280V, it is necessary to limit the applied voltage to about 250V. Therefore, if current is detected for two phases out of the three phases where the phase voltage does not show the maximum level, the maximum value of the phase voltage is not limited, and the efficiency of the motor 24 is improved.

According to the second embodiment configured as described above, the A / D converter 41A detects the currents of the two phases out of the three phases in which the phase voltage does not show the maximum level, based on the conduction electrical angle. Therefore, the duty of the PWM signal can be set to 100% without turning on the IGBT 38 on the lower arm side in the section where the phase voltage shows the maximum level.
The efficiency of 4 can be improved. Inverter circuit 3
When the driving voltage of No. 7 is about 280V, the power consumption can be reduced by about 15W. Note that the same can be applied to the case of performing sinusoidal wave energization using a three-phase modulated wave.

FIG. 17 shows a third embodiment of the present invention, and only parts different from the first embodiment will be described.
In the third embodiment, two shunt resistors connected to the lower arm side of the inverter circuit 37 are connected in series for each phase. That is, for the U phase, resistors 39ua and 39
Resistors 39va and 39vb are arranged for the ub and V phases, and resistors 39wa and 39wb are arranged for the W phase.

Then, the IGBTs 38d, 38e, 38f
Of the amplifiers / bias circuits 40ua, 40v at the common connection point between the emitter of the resistor and the resistors 39ua, 39va, 39wa.
The input terminals of a and 40 wa are connected, and the amplification / bias circuit 40 u is connected to the common connection point of the series circuits of the resistors.
Input terminals b, 40vb, 40wb are connected.
The output terminal of each amplification / bias circuit 40 is connected to the input port of the control section (current detection means) 47B.

Next, the operation of the third embodiment will be described. The load applied to the motor 24 varies according to the operation mode of the washing machine 11 and the amount of current flowing through the windings increases or decreases, but the resistors 39 ub, 39
Current detection is performed on the vb, 39wb side, and the resistors 39ua, 39va, 39wa are used during operation in which the amount of current is relatively small.
The current should be detected on the side.

According to the third embodiment configured as described above, the control unit 47B switches the resistance value of the detection resistor according to the amount of current flowing through the winding of the motor 24, so that the load fluctuation is large. Even when used in the machine 11, current detection can always be performed accurately.

18 to 20 show a fourth embodiment of the present invention. In the fourth embodiment, the shunt resistor 39
u, 39v, 39w have been removed. The output terminals 37v and 37w of the inverter circuit 37 and the motor 24
Between the windings 24v and 24w of the shunt resistor 51
v and 51w are inserted respectively. At both ends of these shunt resistors 51v, 51w, current detection ICs 52v, 5
The 2w input terminal is connected.

The current detection ICs 52v and 52w are, for example, In
IR2171 of ternational Rectifier, etc.,
As shown in FIG. 19, a PWM signal corresponding to the terminal voltage of the shunt resistors 51v and 51w is output to the control unit 47C with a carrier wave of 40 kHz. That is, the input terminal V
When the potential difference between in + and Vin− changes in the range of ± 260 mV, the duty ratio of the PWM signal changes in the range of 93% to 7% and is output. The PWM signals output by the current detection ICs 52v and 52w are
It is given to the input port of the control unit 47C.

Next, the operation of the fourth embodiment will be described with reference to FIG. FIG. 20A shows a current detection IC 5
2 outputs PWM signal waveform and D inside the control unit 47C
FIG. 20 (b) is a flowchart showing the flow of processing executed by the DSP, showing changes in the counter value of the counters (not shown) included in the SP.
The DSP is interrupted by the falling edge of the PWM signal output by the current detection ICs 52v and 52w, and the flowchart of FIG. 20 (subroutine XINTxS
VR) is to be executed.

As shown in FIG. 20 (a), the counter values of the counters are captured by the capture units CAPxFIFO (old) and CAPxFIFO at the rising and falling timings of the PWM signal.
It is designed to be latched by (new). Then, when the DSP starts the processing of FIG. 20B, the two capture units CAPxFIFO (old) and CAPxFI.
The data latched in FO (new) is transferred to the register AR5.
It is read into AR6 (step D1).

Next, the DSP determines the off period Ix of the PWM signal.
Delta1 is calculated (step D2). In this case, the value of the register AR5 is assigned to the variable IxTime1, and the off period IxDelt is set.
Calculate a1 by the following formula. IxDelta1 = IxTime1-IxTime2 (3) Here, the counter value at the falling timing of the PWM signal in the immediately preceding cycle is substituted for IxTime2 in step D3 described below.

Subsequently, the DSP is in the ON period of the PWM signal.
IxDelta2 is calculated (step D3). In this case, the value of the register AR6 is substituted into the variable IxTime2, and the ON period IxDe
Calculate lta2 by the following formula. IxDelta2 = IxTime2-IxTime1 (4) Then, the DSP calculates the current value Ix (step D
4). The current value Ix is the on period IxDelta2 and the off period IxDe
It is obtained by dividing by the sum of lta1 and ON period IxDelta2. That is, Ix = IxDelta2 / (IxDelta1 + IxDelta2) (5)

As described above, according to the fourth embodiment, the shunt resistors 51v, 51 are provided between the output terminals 37v, 37w of the inverter circuit 37 and the windings 24v, 24w of the motor 24.
Since the current detection ICs 52v and 52w are connected to both ends of these shunt resistors 51v and 51w by inserting w, and the current is detected based on the PWM signal output from these current detection ICs 52v and 52w, the first or The same effect as the second embodiment can be obtained.

The present invention is not limited to the embodiments described above and shown in the drawings, and the following modifications or expansions are possible. The vector control may be performed at least only for the washing operation and the dehydration operation. The control cycle of the speed control is not limited to 1 msec, but can be set sufficiently within a range of 50 msec to sufficiently obtain the effect of suppressing noise and vibration. Further, the control gain used for the speed PI control may be changed according to the rotation speed of the motor 24. For example, when the rotation speed of the motor 24 reaches near the natural frequency of the vibration system centering on the rotary tank 15 or the like, the value of the control gain is set to be larger so that the PI control acts more strongly. If so, it is possible to effectively suppress the occurrence of vibration. In this case, the control gain used for the speed PI control may be changed at least in each of the washing operation and the dehydration operation. That is, since the driving conditions of the motor 24 are greatly different between the washing operation and the dehydration operation, the vibration can be effectively suppressed by setting the control gain to an appropriate value according to each driving condition.

The current detection of the motor may be performed by using a current transformer. In the third embodiment, three or more current detecting resistors may be connected in series. In the fourth embodiment, as in the third embodiment, a plurality of shunt resistors are connected in series, current detection ICs corresponding to the number of resistors are prepared, and the detection points are switched according to the magnitude of the current amount. You may.

[0084]

According to the washing machine of the present invention, the torque control means detects the electric current flowing through the motor for generating the rotational driving force for performing the washing, rinsing and dehydrating operations, and the motor is detected based on the detected electric current. Is controlled by the vector control so that the generated torque of the motor is optimal at least for each of the washing operation and the dehydration operation, so that the torque of the motor can be directly controlled in proportion to the q-axis current. Therefore, the responsiveness can be improved as compared with the conventional motor control, and noise and vibration can be reduced. Further, the outer box of the washing machine can be constructed in a small size, and the wasteful driving force of the motor can be reduced to obtain an energy saving effect, and the washing power can be improved.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a configuration of a control system of a fully automatic washing machine, which is a first embodiment of the present invention.

FIG. 2 is a diagram showing a detailed electrical configuration centered on an inverter circuit.

FIG. 3 is a vertical sectional view showing the overall configuration of a fully automatic washing machine.

FIG. 4 is a flowchart showing a schematic control content mainly by a control microcomputer.

FIG. 5 is a diagram showing waveforms of PWM carrier waves and gate signals on the upper arm side and the lower arm side.

FIG. 6 is a waveform diagram showing the relationship between the reverse IMINV of the motor phase current, the current ISR flowing through the shunt resistor, and the phase voltage.

FIG. 7 is a diagram showing a state in which the rotation speed fluctuates when the rotary tank is rotated at 250 rpm, (a) shows the case of the configuration of the present embodiment, and (b) shows the case of the conventional configuration.

FIG. 8 is a diagram showing the shaking amount (displacement amount) of the rotary tank at the start of the dehydration operation (this embodiment).

FIG. 9 is a view corresponding to FIG. 8 (conventional configuration).

FIG. 10 is a diagram comparing noise levels generated by the conventional configuration and the configuration of this embodiment, respectively.

FIG. 11 is a diagram showing a target speed command ωref and a motor rotation speed ω during a washing operation.

FIG. 12 is a diagram showing a duty command Duty and a motor rotation speed ω output by a PI control unit in a conventional configuration.

FIG. 13 is a view corresponding to FIG. 2 showing a second embodiment of the present invention.

FIG. 14 is a diagram showing a state in which an A / D conversion unit switches inputs to a 2-channel converter.

FIG. 15 is a diagram showing a timing for detecting a motor phase voltage and each phase current.

FIG. 16 is a diagram showing the relationship between the maximum output voltage (phase voltage) of the motor and the power consumption.

FIG. 17 is a view corresponding to FIG. 2 showing a third embodiment of the present invention.

FIG. 18 is a view corresponding to FIG. 2 showing a fourth embodiment of the present invention.

FIG. 19 is a diagram showing a PWM signal waveform output from a current detection IC.

20A is a diagram showing a PWM signal waveform output from a current detection IC and a change in a counter value of a counter included in a DSP in a control unit, and FIG. 20B is a flowchart of calculation processing performed by the DSP.

FIG. 21 is a view corresponding to FIG. 1 showing a conventional technique.

[Explanation of symbols]

11 is a fully automatic washing machine, 24 is a brushless motor, 27 is a speed PI control unit (speed control means), 37 is an inverter circuit, 38a to 38f are IGBTs (switching elements),
39u, 39v and 39w are shunt resistors (current detecting means), 41 and 41A are A / D converters (current detecting means),
Reference numeral 45 is a DSP (torque control means), 47B is a control unit (current detection means), and 52v and 52w are current detection ICs.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoji Okazaki             991, Anada-cho, Seto-shi, Aichi Higashi Co., Ltd.             Shiba Aichi Factory (72) Inventor Michiaki Ito             991, Anada-cho, Seto-shi, Aichi Higashi Co., Ltd.             Shiba Aichi Factory (72) Inventor Shinichiro Kawabata             991, Anada-cho, Seto-shi, Aichi Higashi Co., Ltd.             Shiba Aichi Factory (72) Inventor Kazunobu Nagai             33, Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa             Inside the Toshiba Production Technology Center (72) Inventor Fuse Isono             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Ceremony Company Toshiba Microelectronics Sen             Inside F-term (reference) 3B155 AA01 AA03 AA06 BA04 BB15                       BB18 CB06 HB10 KA32 KA33                       KB08 LB18 LB26 LC08 LC15                       MA06 MA07 MA08 MA09                 5H560 AA10 BB04 BB07 BB12 DA02                       DB20 DC12 DC13 EB01 EB05                       EC01 EC10 JJ02 RR01 SS07                       TT10 UA02 XA02 XA04 XA11                       XA12 XA13 XB08                 5H576 AA12 BB04 CC05 DD02 DD04                       DD07 EE01 EE11 GG02 GG04                       HA02 HB02 JJ04 JJ24 LL22                       LL24 LL41 MM02

Claims (10)

[Claims] 1. A motor for generating a rotational driving force for performing washing, rinsing and dehydration operations, a current detecting means for detecting a current flowing through the motor, and the current based on the current detected by the current detecting means. A washing machine comprising: a vector control unit for controlling the motor so that the generated torque of the motor is optimized at least for each of the washing operation and the dehydration operation. 2. An inverter circuit for driving a motor, wherein the current detecting means detects a current flowing through a resistor connected in series with a switching element on the lower arm side which constitutes the inverter circuit. The washing machine according to claim 1. 3. The motor has a three-phase configuration, and the current detection means detects a current for two phases out of the three phases, in which the phase voltage does not show the maximum level, based on the energized electrical angle. Item 2. A washing machine according to item 2. 4. A series circuit is composed of a plurality of resistors connected in series with a switching element on the lower arm side, and the current detecting means switches a detection position in the series circuit according to a load condition. The washing machine according to claim 2 or 3, wherein the washing machine is configured. 5. The motor speed PI based on the speed command and the rotation speed of the motor obtained from the current detected by the current detection means in the preceding stage of the torque control means.
The washing machine according to any one of claims 1 to 4, further comprising a speed control means for controlling. 6. The speed control means outputs q-axis and d-axis current command values to the torque control means, and the torque control means detects the q-axis and d-axis current command values and current detection means. 6. The washing machine according to claim 5, wherein the q-axis and d-axis voltage command values are generated by performing PI control based on the q-axis and d-axis current values of the motor obtained from the current. 7. The washing machine according to claim 5, wherein the speed control means changes the control gain used for PI control according to the rotation speed of the motor. 8. The washing machine according to claim 5, wherein the speed control means changes the control gain used for PI control at least for each of the washing operation and the dehydration operation. . 9. The control cycle of the speed control means is 50 m.
The washing machine according to claim 5, wherein the washing machine is set within a second. 10. The washing machine according to claim 1, wherein the torque control means starts the control at the time when the rotation speed of the motor rises to a predetermined speed.