JP6634603B2 - Washing machine - Google Patents

Description

  The present invention relates to a washing machine that controls a rotation speed by driving a motor that drives a stirring blade or a washing and dewatering tub by an inverter circuit, and particularly to a stop determination by sensorless position estimation.

  2. Description of the Related Art In recent years, there has been proposed a home-use washing machine in which an inverter circuit controls a rotation speed of a DC brushless motor that drives a stirring blade or a washing and dewatering tub to improve dehydration performance or cleaning performance.

  In a DC brushless motor, in order to sequentially switch and supply a drive current to each phase motor winding at a predetermined commutation operation timing with respect to each phase motor winding, a relative winding between the motor winding and the rotor is used. Conventionally, this type of washing machine has been configured, for example, as described in Japanese Patent Application Laid-Open Publication No. H11-157572, since it requires specific position information, that is, magnetic pole position information. That is, a sinusoidal three-phase AC voltage waveform is generated by an inverter circuit from an output signal of a rotor detecting means constituted by a Hall IC, and a DC brushless motor for driving a stirring blade or a washing and dewatering tank is driven. .

  On the other hand, the Hall element as described above has a temperature dependency and a cost reduction of parts. For the purpose of, for example, Japanese Patent Application Laid-Open No. H11-163,197, as a motor control method, a sensorless position estimation control is often used. Proposals have been made, and studies on sensorless use in home-use washing machines are in progress.

  Also, in the washing machine, a lock mechanism is provided on the door of the laundry inlet for safety, and the door is locked in a closed state during operation, and unlocked at the end of operation or at the time of temporary stop. In this case, the washing and dewatering tub is generally configured to be released after detecting that it has dropped below a predetermined number of revolutions (substantially stopped state).

JP 2000-324873 A JP 2013-90552 A

  The sensorless position estimation method can be roughly classified into a method of detecting a position from an induced voltage generated with rotation of a motor, and a method of superposing a high-frequency current on a drive current and detecting a position from a response current. In the method of detecting the position by the induced voltage, at a low speed, the induced voltage generated is low and the accuracy of the position detection cannot be secured, so that the stop determination cannot be performed. On the other hand, in the method of superimposing a high-frequency current, a high-frequency sound is generated from the motor by a pulse current applied to a winding of the motor. In particular, after the motor is stopped, that is, when the agitation sound of the laundry or the water is low, the sound is conspicuous, and may cause anxiety or discomfort to the user. Conversely, if the superimposed current is too small to make the high-frequency sound inconspicuous, the estimated rotation speed fluctuates and diverges due to a decrease in the accuracy of position detection, and the motor stop may not be detected, and the door lock may not be released. There were challenges.

The present invention solves the above-mentioned conventional problems, and provides a washing machine that performs stop determination based on sensorless position estimation, in which the reliability of the stop determination is ensured and the occurrence of high-frequency noise is suppressed. The purpose is.

In order to solve the conventional problems, the present invention provides a washing and dewatering tub for storing laundry, an input port for taking in and out the laundry into and out of the washing and dehydrating tub, and a door for closing the input port so as to be openable and closable, A door lock means for locking the door in a closed state, wherein the door lock means locks the door in a closed state during operation and unlocks the door when operation is stopped. A circuit, an inverter circuit that converts DC power output from the rectifier circuit into AC power, a motor that has an electrical saliency in a rotor, is driven by the inverter circuit, and stirs laundry. A current detection unit for detecting a motor current of the motor; and a control unit for controlling the inverter circuit based on the motor current detected by the current detection unit, wherein the control unit The single pulse voltage or current for each cycle of Jo Tokoro, and supplied through the inverter circuit, by measuring the response current of the motor, using a sensorless position estimation scheme for estimating a magnetic pole position of the rotor Estimating the motor rotation speed of the motor, after stopping the driving of the motor, set the single pulse voltage or current, and determine whether the estimated rotation speed of the motor has decreased to less than a first predetermined rotation speed. A determination is made as to whether the motor is to be stopped, and if the estimated rotation speed of the motor is equal to or greater than a first predetermined rotation speed, a first predetermined time has elapsed from the start of the determination to stop the motor , and the estimation of the motor is performed. when the rotation speed is not decreasing direction, the single pulse voltage or current, the motor is set larger than the value set at the start of the stop determination, the estimated rotation speed of the motor is the first predetermined rotational speed not If it becomes a configuration the washing machine so as to release the lock by the door locking means.

  With this, after the motor drive is stopped, the stop judgment is performed by superimposing a pulse current to such an extent that the high frequency sound is inconspicuous, thereby suppressing the generation of the high frequency sound and, when the estimated rotation speed fluctuates or diverges, the rotation is stopped. By increasing the superimposed pulse current in the direction in which the numbers converge, the reliability of the stop determination can be ensured.

  Further, if the estimated rotation speed of the motor is in a decreasing direction after the elapse of the first predetermined time, the control means holds the single-pulse voltage or current at that time to minimize the occurrence of high-frequency sound. It is possible to suppress.

  Further, the control means, if the estimated rotation speed of the motor does not decrease in the second predetermined time after the elapse of the first predetermined time, further increases the estimated rotation speed at that time. By resetting to a value larger than the first predetermined rotation speed and continuing estimation of the magnetic pole position of the rotor, when the actual rotation speed is sufficiently reduced, the diverged estimated rotation speed is reduced. It is possible to quickly follow the actual rotation speed, and as a result, the generation time of high-frequency sound can be suppressed. During the stop determination, the torque current is substantially zero, and if there is no abnormality in the system, in the case of the above state, the actual rotational speed should be sufficiently reduced.

  Further, the control means changes the first or second predetermined time according to the target rotation speed or the capacity of the laundry at the time of driving the motor immediately before the door is unlocked, so that more optimal control is performed. It is also possible to do. In other words, the higher the rotation speed immediately before the stop determination, and the larger the capacity of the laundry, the longer the time required for stopping the motor.Therefore, by optimally adjusting the timing of the start of the increase of the superimposed current accordingly, The suppression of high-frequency sound generation can be optimized.

  ADVANTAGE OF THE INVENTION According to this invention, the sensorless position estimation of the washing machine which suppressed generation | occurrence | production of high frequency sound can be performed, ensuring the reliability of especially a stop determination.

Circuit block diagram of a washing machine according to Embodiment 1 of the present invention. Block diagram of control means of the washing machine Time chart when the motor of the washing machine is stopped Flow chart when the motor of the washing machine is stopped Vertical sectional view of the washing machine

According to a first aspect of the present invention, there is provided a washing and dewatering tub for storing laundry, an input port for taking in and out of the laundry into and out of the washing and dewatering tub, a door for opening and closing the input port, and locking the door in a closed state. A rectifier circuit connected to a commercial power supply, wherein the rectifier circuit is connected to a commercial power supply in a washing machine that locks the door in a closed state by the door lock means during operation and unlocks the door when operation is stopped. An inverter circuit that converts the output DC power into AC power, a motor that has an electrical saliency in the rotor and is driven by the inverter circuit to stir the laundry, and detects a motor current of the motor. a current detection means, and control means for controlling said inverter circuit based on the motor current detected by said current detecting means, the control means is a single pulse every period of Jo Tokoro The pressure or current, is supplied via the inverter circuit, by measuring the response current of the motor, estimating the motor rotation speed of the motor using a sensorless position estimation scheme for estimating a magnetic pole position of the rotor After the driving of the motor is stopped, the single pulse voltage or the current is set, and a stop determination of the motor is performed to determine whether the estimated rotation speed of the motor has decreased to less than a first predetermined rotation speed , If the estimated rotation speed of the motor is equal to or greater than a first predetermined rotation speed, the first predetermined time has elapsed from the start of the motor stop determination, and if the estimated rotation speed of the motor is not in a decreasing direction, single pulse voltage or current, the set larger than the start value set during the stop determination of the motor, when the estimated rotation speed of the motor becomes lower than the first predetermined rotational speed, the door locking means Is a configuration the washing machine so as to release the lock due.

  With this, after the motor drive is stopped, the stop judgment is performed by superimposing a pulse current to such an extent that the high frequency sound is inconspicuous, thereby suppressing the generation of the high frequency sound and, when the estimated rotation speed fluctuates or diverges, the rotation is stopped. By increasing the superimposed pulse current in the direction in which the numbers converge, the reliability of the stop determination can be ensured.

In a second aspect based on the first aspect, the control means reduces the estimated rotation speed of the motor in a decreasing direction even if a first predetermined time has elapsed since the start of the motor stop determination. If there is, the stop determination is continuously performed while holding the single pulse voltage or current at that time, so that the estimated rotational speed only decreases (ie, the estimated rotational speed converges (follows) toward the actual rotational speed). Since the superimposed current can be ensured, it is possible to minimize the occurrence of high-frequency noise while ensuring the reliability of the stop determination.

In a third aspect based on the first or second aspect, the control means is configured to reduce the estimated rotation speed of the motor even after a lapse of the first predetermined time and a lapse of a second predetermined time or more. If the direction does not decrease, the estimated rotation speed of the motor at that time is reset to a value larger than the first predetermined rotation speed, and the stop determination of the motor is continued. Since the torque current is substantially zero, if there is no abnormality in the system, in the case of the above-described state, the estimated rotation speed does not follow the actual rotation speed even though the actual rotation speed is sufficiently reduced. It is conceivable that the difference from the actual rotation speed is too large. In this case, by resetting the estimated rotation speed to be lower than the estimated rotation speed in the diverging state as described above, the diverged estimated rotation speed can quickly follow the actual rotation speed. Generation time can be suppressed.

In a fourth aspect based on the first to third aspects, the control means is arranged to control the first or the first or the second rotation in response to a target rotation speed and / or a capacity of the laundry when the motor is driven immediately before the door lock is released. And by changing the second predetermined time, the higher the number of rotations immediately before the stop determination and the greater the capacity of the laundry, the longer the time of inertial rotation, that is, the time required for stopping the motor, and accordingly, By optimally adjusting the timing of the start of the increase of the superimposed current, the suppression of the generation of the high-frequency sound can be optimized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited by the embodiment.

(Embodiment 1)
Hereinafter, a washing machine according to Embodiment 1 of the present invention will be described with reference to the drawings.

  In the washing machine according to the present embodiment, a drum-type washing machine equipped with only a washing and dewatering tub is not used as the first embodiment, and the stirring blade described in the conventional example of the background art is not installed. However, it may be used for a washing machine equipped with a stirring blade.

  FIG. 1 is a circuit block diagram of a washing machine according to Embodiment 1 of the present invention. As shown in FIG. 1, a commercial power supply 1 is input to a rectifier circuit 3 via a line filter 2, and is converted into DC power. The rectifier circuit 3 forms a voltage doubler rectifier circuit as shown below. The AC voltage input to the rectifier circuit 3 is charged by the full-wave rectifier diode 3a to the capacitor 3b when the input voltage is a positive voltage and to the capacitor 3c when the input voltage is a negative voltage. As a result, a double voltage DC voltage is generated at both ends of the capacitors 3 b and 3 c connected in series, and the double voltage DC voltage is input to the inverter circuit 5 and the door lock means 4.

  The inverter circuit 5 is constituted by a three-phase full-bridge inverter circuit composed of six power switching semiconductors and an anti-parallel diode, and is integrally constituted by an intelligent power module (hereinafter referred to as IPM) incorporating a drive circuit and a protection circuit. I have. The motor 6 is connected to the output terminal of the inverter circuit 5 to drive the washing and dewatering tub 31 shown in FIG. The motor 6 is a DC brushless motor having an electric saliency.

  A current detecting means 8 for detecting an input current of the inverter circuit 5, that is, a so-called shunt resistor is connected between the negative voltage terminal of the inverter circuit 5 and the negative voltage terminal of the rectifier circuit 3.

  A water supply valve 9 and a drain valve 10 are connected between output terminals of the line filter 2 and controlled by a switching means 12 constituted by a solid state relay such as a bidirectional thyristor or a mechanical relay.

  Here, the configuration of the washing machine will be described.

  FIG. 5 is a longitudinal sectional view of the washing machine according to Embodiment 1 of the present invention. As shown in FIG. 5, the outer tub 33 includes a washing and dewatering tub 31 rotatably disposed therein, and is suspended from the outer frame 30 of the washing machine by a hanging rod (not shown). The motor 6 rotationally drives the washing and dewatering tub 31 via a speed reduction mechanism. A door 35 is provided in front of the outer tub 33 so as to open and close in correspondence with an input port 34 for taking in and out of the laundry. The door 35 is provided at a locking portion between the door 35 and the outer frame 30 of the washing machine. A door lock means 4 (not shown) is provided for locking and opening / closing the door 35 in a closed state. The water supply valve 9 is an electromagnetic valve for supplying tap water to the washing and dewatering tub 31, and the drain valve 10 controls drainage of water in the washing and dewatering tub 31.

  Power is supplied to the control circuit 16 by pressing a power switch (not shown) arranged on the operation panel 13 provided on the upper front surface of the washing machine outer frame 30. As shown in FIG. 1, a relay 15 serving as a switch is provided to maintain power even after a power switch (not shown) is released. 17 controls its opening and closing.

  In the above configuration, the control circuit 16 drives the door lock means 4 by pressing an operation switch (not shown) arranged on the operation panel 13 in a power-on state, so that the door 35 After locking in the closed state, start operation.

  After the start of operation, the control circuit 16 controls the switching means 12 to control the operations of the water supply valve 9, the drainage valve 10, and the like, and controls a series of steps of washing, rinsing, and dehydration (detailed description of the control operation). Is omitted). In the washing process, the washing and dewatering tub 31 is rotated to the left and right to apply a mechanical force to the cloth to remove dirt from the clothes. Operate to squeeze water from clothing. After a series of operations is completed, the control means 17 confirms that the rotation of the washing and dewatering tub 31 has been sufficiently reduced, then unlocks the door 35, turns off the relay 15, and performs all operations. Complete.

  In addition, at the time of a power failure during operation and at the time of turning off a switch (not shown) or a temporary stop switch (not shown) arranged on the operation panel 13, the motor 6 is decelerated and stopped, and the control means 17 is stopped. After confirming that the rotation of the washing / dewatering tub 31 has been sufficiently reduced, the lock of the door 35 is released. At the time of a power failure and at the time of stoppage by the off switch, after the lock is released, the relay 15 is turned off, and all operations are completed.

  Hereinafter, details of the control of the motor 6 will be described with reference to FIGS. FIG. 2 is a block diagram of control means of the washing machine according to Embodiment 1 of the present invention, and FIG. 3 is a time chart when the motor of the washing machine is stopped.

  The control means 17 receives the three-phase (U, V, W) current values Iu, Iv, Iw of the motor 6 detected by the current detection means 8 as inputs, and outputs a current component Id in the magnetic flux direction of the rotor of the motor 6 and the current component Id. A uvw → dq current conversion unit 170 that converts the current component into an orthogonal current component Iq, a position estimation φ operation unit 171 that estimates the position of the rotor from the dq currents Id and Iq, and a pulse current to be superimposed on the drive current. A pulse current control unit 172 for controlling, an angular velocity ω calculating unit 173 for calculating an angular velocity ω from the position estimation value φ, and a position angle θ from the position estimation value φ and the angular velocity ω, and the result is converted to a uvw → dq current conversion unit. The current command value is updated by feeding back the current command value by feeding back to the position angle θ calculation unit 174 that outputs to the dq → uvw voltage conversion unit 176 and the estimated angular velocity ω and the speed command value ω *. The speed current control unit 175 and the voltage command Vd in the magnetic flux direction of the rotor and the voltage command Vq in the direction orthogonal thereto input from the speed current control unit 175 are converted into three-phase voltage commands Vu, Vv, Vw of the motor 6. It comprises a dq → uvw voltage converter 176 which converts and outputs it to the inverter circuit 5.

  Here, the uvw → dq current conversion, dq → uvw voltage conversion, and speed feedback control are general methods, and their descriptions are omitted, and the position estimation φ calculation unit 171, pulse current control unit 172, angular velocity ω calculation The overall processing of the unit 173 and the position angle θ calculation unit 174 will be described in more detail.

  The magnetic pole position is estimated based on the following basic formula.

In a DC brushless motor having saliency, when a single-pulse voltage or current is applied at predetermined intervals with respect to the dq axis rotation coordinates, the current response changes depending on the applied direction. Make an estimate.

  In the present embodiment, during driving of the motor 6, a voltage pulse corresponding to 0.4 A is applied to the d-axis (estimated d-axis), which is the direction of the magnetic flux of the rotor, and q is the direction orthogonal to the direction of the magnetic flux of the rotor. The current response of the axis (estimated q axis) is measured. If the estimated d-axis matches the actual d-axis (if the position angle θ and the angular velocity ω are correctly detected), the q-axis currents when the pulse is applied and when the pulse is not applied are almost the same value. Therefore, the difference between the q-axis currents when the pulse is applied and when the pulse is not applied is defined as “Φ” (position error) in the above equation.

  More specifically, a pulse voltage (equivalent to 0.4 A during motor driving) of 400 μs width is applied in the d-axis (estimated d-axis) direction at a period of 2.5 ms, and the q-axis (estimated The difference between the q-axis) current value and the q-axis (estimated q-axis) current when no pulse is applied is calculated by the position angle θ calculation unit 174 and used as Φ (position error) in the above equation. The position error Φ obtained in this way is fed back to the angular velocity ω calculator 173 and the position angle θ calculator 174 so that the position angle θ and the angular velocity ω follow actual values. FIG. 3 shows a current waveform when a pulse is applied as described above.

  The feedback of the position error Φ is performed according to the following equation.

  Hereinafter, control when the motor 6 is stopped will be described with reference to FIG. FIG. 4 is a flowchart when the motor of the washing machine is stopped according to Embodiment 1 of the present invention. In the present embodiment, a series of operations starting from the pressing of the pause switch during driving as a trigger until the door lock is released will be described. Note that the operations up to the door lock release at the end of operation, at the time of a power failure, and at the time of pressing the off switch are the same as those at the time of pressing the temporary stop switch, and thus the description thereof is omitted.

  When the temporary stop switch is pressed, it is determined in step 1 whether or not the motor is being driven. If the motor is not being driven, in step 2, the timings t1, t2, and t3 at which the pulse current is increased are set 2 seconds, 4 seconds, and 5 seconds after the start of the stop determination, and the initial estimated rotation speed is set to 20r. / Min temporarily. If the motor is being driven, t1, t2, and t3 are set according to the target rotation speed of the washing and dewatering tub 31 according to the following table, and the initial estimated rotation speed is provisionally set to the same value as the target rotation speed. Stop the drive signal to The rotation speed of the washing and dewatering tub 31 is calculated from the angular velocity of the motor 6 and the reduction ratio of the motor 6 and the washing and dewatering tub 31.

  Next, in step 3, as a preparation for the stop determination, a timer (stop determination timer (t)) for measuring the timing of increasing the pulse current is reset, and the pulse current value to be superimposed on the d-axis current is set to 0.25 A. Set to. The set value of the pulse current of 0.25 A is a pulse current value at which high-frequency sound is inconspicuous. In addition, the frequency is not limited to 0.25 A as long as the high frequency sound is inconspicuous.

  The stop determination is made after step 4.

  First, in step 4, the stop determination timer (t) is counted up.

  Next, in step 5, the stop determination timer (t) is compared with the above-described t1, t2, and t3. When t <t1, or when the estimated rotation speed is in the decreasing direction, the setting of the pulse current value to be superimposed on the d-axis current is fixed, but otherwise, t1, t2, and t3 from the start of the stop determination. , The pulse current is reset to 0.3 A, the pulse current is reset to 0.4 A, and the estimated rotation speed is reset to 8 r / min.

  Next, in step 6, a predetermined pulse current is superimposed on the d-axis current by the method described above, and the rotation speed is estimated. In step 7, whether the rotation speed has sufficiently decreased, that is, the estimated rotation speed, Is determined to be less than 5 r / min, and if less than 5 r / min, it is determined to be stopped, and in step 8, the pulse current is turned off and the door is unlocked.

  In step 7, if the rotation speed is 5 r / min or more, the stop determination is continued from step 4 again.

  Hereinafter, the operation of the above configuration will be described with reference to FIG. The time chart shown in FIG. 3 shows the number of revolutions, the pulse current value, and the number of rotations of the washing and spin-drying tub 31 from when the operation is temporarily stopped by the stop switch immediately after the motor 6 is stopped to when the door lock is released. 6 shows one phase current (only one phase). In the time chart of the rotation speed, the solid line represents the estimated rotation speed in the present embodiment, the broken line represents the actual rotation speed, and the dashed line represents the estimated rotation speed in the conventional method.

  After the driving of the motor 6 is stopped, the actual number of revolutions of the washing and dewatering tub 31 gradually decreases as shown by the broken line due to the inertial rotation. Since the pulse current is not superimposed during the period from when the motor 6 stops driving to when the pause switch is pressed, the number of rotations and the magnetic pole position are unknown.

  When the temporary stop switch is pressed, 20 r / min is temporarily set as the estimated rotation speed, the superposition of the pulse current (0.25 A) is started, and thereafter, the rotation speed estimation and the stop determination are performed as described above.

After that, in most cases, the estimated rotation speed changes as indicated by a two-dot chain line and follows the actual rotation speed, falls below 5 r / min after about 3 seconds, the pulse current is turned off, and the door lock is released. However, depending on the behavior of the clothes in the washing and dewatering tub 31, the estimated number of revolutions rarely diverges as indicated by the dashed line, and the door lock may not be released forever.

  In the configuration of the present embodiment, as in step 6 shown in FIG. 4, the pulse currents are changed from 0.25 A to 0.3 A, 0 A at t1 seconds (2 seconds) and t2 seconds (4 seconds) from the start of the stop determination. By increasing from 3 A to 0.4 A, the accuracy of detecting the magnetic pole position of the rotor is improved, and the follow-up of the estimated rotational speed is promoted. If the estimated rotation speed still does not follow, the estimated rotation speed is returned to 8 r / min after t3 seconds (5 seconds), that is, the deviation between the estimated rotation speed and the actual rotation speed is reduced, and the rotation speed estimation is restarted from the beginning. It encourages following. The number of seconds shown in parentheses of t1, t2, and t3 is an example of the number of seconds when the target rotation speed in the above table is 35 r / min or less.

  As described above, according to the washing machine of the present invention, before the door is unlocked, after the motor drive is stopped, first, the stop determination (rotation speed estimation) is performed by superimposing a pulse current to such an extent that high-frequency sound is inconspicuous. By suppressing the occurrence of high-frequency sound and increasing the superimposed pulse current in the direction in which the rotational speed converges when the estimated rotational speed fluctuates / diverges, the reliability of the stop determination can be ensured.

  Further, after the first predetermined time (t1 in the above embodiment) elapses, the pulse current stops increasing when the estimated rotational speed decreases, so that the estimated rotational speed decreases in the decreasing direction, that is, the estimated rotational speed. Since it is possible to secure a superimposed current enough to converge (follow) the actual rotation speed, it is possible to minimize the generation of high-frequency noise while ensuring the reliability of the stop determination.

  In addition, when the estimated rotation speed does not decrease, the first predetermined time (t1 in the above embodiment) elapses and the second predetermined time (t3 in the above embodiment) elapses. Resets the current estimated rotational speed to a value slightly larger than the first predetermined rotational speed (5 r / min in the above embodiment) (8 r / min in the above embodiment), and then continues position estimation. By doing so, it is possible to cause the estimated rotational speed once diverged to quickly follow the actual rotational speed, and as a result, it is possible to suppress the generation time of high-frequency sound.

  In addition, the higher the rotation speed immediately before the stop determination and the larger the capacity of the laundry, the longer the time of inertial rotation, that is, the time required for stopping the motor. By performing optimal adjustment, suppression of generation of high-frequency sound can be optimized.

  Although not included in the above embodiment, if a means for detecting the amount of laundry such as clothes put in is provided, in step 2, t 1, t 2, and t 3 are determined in accordance with the detected amount of clothes. And / or the initial estimated rotational speed can be set.

  Further, in the above-described embodiment, a drum type washing machine equipped with only a washing and dewatering tub has been described. However, the present invention can be applied to a washing machine of a type in which laundry is stirred and washed by stirring blades.

  As described above, the washing machine according to the present invention suppresses the generation of high-frequency noise while ensuring the reliability of the motor stop determination for the home washing machine controlled using the sensorless position estimation method. It can be used not only for home-use washing machines, but also for washing and drying machines having a drying function, as well as business-use washing machines and washing / drying machines.

DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 Line filter 3 Rectifier circuit 3a Full-wave rectifier diode 3b Capacitor 3c Capacitor 4 Door lock means 5 Inverter circuit 6 Motor 8 Current detection means 9 Water supply valve 10 Drain valve 12 Switching means 13 Operation panel 14 Relay drive circuit 15 Relay ( Switch)
Reference Signs List 16 control circuit 17 control means 30 washing machine outer frame 31 washing and dewatering tub 33 outer tub 34 inlet 35 door

Claims (4)

A washing and dewatering tub for storing laundry, an input port for taking in and out of the laundry into and out of the washing and dewatering tub, a door for opening and closing the input port, and a door lock means for locking the door in a closed state. A washing machine that locks the door in a closed state by the door locking means during operation and unlocks the door when operation is stopped, a rectifier circuit connected to a commercial power supply, and a DC power output from the rectifier circuit. An inverter circuit for converting into AC power, a motor having an electrical saliency in the rotor, driven by the inverter circuit, for stirring the laundry, a current detecting means for detecting a motor current of the motor, Control means for controlling the inverter circuit based on the motor current detected by the current detection means,
It said control means, a single pulse voltage or current for each cycle of Jo Tokoro, and supplied through the inverter circuit, by measuring the response current of the motor, sensorless position estimation for estimating a magnetic pole position of the rotor Estimating the number of rotations of the motor using a method ,
After the driving of the motor is stopped, the single-pulse voltage or current is set, and the motor stop determination is performed to determine whether the estimated rotation speed of the motor has decreased to less than a first predetermined rotation speed. If the estimated rotation speed of the motor is equal to or greater than the first predetermined rotation speed, if the first predetermined time has elapsed from the start of the motor stop determination and the estimated rotation speed of the motor is not decreasing, the single pulse The voltage or the current is set to be larger than the value set at the start of the motor stop determination, and when the estimated rotation speed of the motor becomes less than the first predetermined rotation speed , the lock by the door lock unit is released. Composed washing machine. Said control means, even after lapse of the first predetermined time from the start of the stop determination of the motor, estimated rotation speed of the motor if the decreasing direction, holding a single pulse voltage or current at that time The washing machine according to claim 1, wherein the determination of the stop of the motor is continuously performed . The control means, if the estimated rotation speed of the motor does not decrease in the second predetermined time after the elapse of the first predetermined time, further increases the estimated rotation speed of the motor at that time. 3. The washing machine according to claim 1, wherein, after resetting the rotation speed to a value greater than the first predetermined rotation speed, the stop determination of the motor is continued. 4. The control device according to claim 1, wherein the control unit changes the first or second predetermined time according to a target rotation speed and / or a capacity of the laundry when the motor is driven immediately before the door is unlocked. 5. The washing machine according to claim 1.

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