CN113249929A

CN113249929A - Washing machine

Info

Publication number: CN113249929A
Application number: CN202010997071.9A
Authority: CN
Inventors: 马饲野祐贵; 吉野知也; 铃木尚礼; 黑泽真理; 法月邦彦
Original assignee: Hitachi Global Life Solutions Inc
Current assignee: Hitachi Global Life Solutions Inc
Priority date: 2020-02-13
Filing date: 2020-09-21
Publication date: 2021-08-13
Also published as: JP2021126327A

Abstract

The invention provides a washing machine which can decelerate a washing drum in a short time without generating large unnecessary noise. The washing machine (W) is provided with an outer cylinder (37), a washing cylinder (35) arranged in the outer cylinder (37), a motor for providing rotary force for the washing cylinder (35), a first control part for controlling the motor, a linear actuator (10) connected with the outer cylinder (37), a second control part for controlling the linear actuator (10), and a DC power supply shared by the first control part and the second control part, wherein the second control part controls the current flowing through the linear actuator during the deceleration action of the motor, so that the length of the linear actuator (10) is shortened or lengthened.

Description

Washing machine

Technical Field

The present invention relates to a washing machine capable of decelerating a washing drum in a short time.

Background

In the washing machine, an outer tub is located inside a cabinet, and a washing tub that rotates inside the outer tub is provided. The washing drum obtains a rotational force by a motor disposed outside the outer drum. Here, the outer cylinder is supported by a suspension provided between the upper and lower portions inside the cabinet. The suspension not only statically supports the washing tub, but also suppresses vibration of the outer tub caused by rotation of the washing tub. In addition, the clothes dewatering process is performed by rotating the washing drum at a high speed. In recent years, demands for larger capacity and shorter time of washing machines have been increased, and the washing tub has been made larger in diameter and higher in rotation speed. Therefore, the centrifugal force generated along with the rotation is also increasing.

If the clothes distribution in the tub is eccentric, a large centrifugal force is generated in the tub to generate vibration. In order to suppress such vibrations, a damping system using an electric actuator for a suspension is known, and a linear motor is used, for example. In a suspension using a linear motor, a current is controlled to control vibration in accordance with a resonance characteristic that varies for each rotational frequency of a washing machine. When the vibration is suppressed, the regeneration operation is performed to absorb the vibration energy from the washing tub.

However, when the washing tub rotating at a high speed is stopped, the motor performs a regenerative operation to generate a braking torque in order to decelerate the washing tub as quickly as possible. During this regenerative operation, an inverter control device that supplies voltage to the motor is used to perform current control so that the motor generates braking torque, and the generated regenerative power is charged in a capacitor constituting a dc power supply circuit connected to the inverter control device. That is, the voltage of the dc power supply rises.

Here, in the damper system using the linear motor as described above, since the regenerative operation is performed also when suppressing the vibration, the regenerative electric power is generated.

Therefore, the capacitor is charged with the regenerative power from the damper system in addition to the regenerative power from the motor. In the capacitor, an allowable withstand voltage is determined, and when regenerative power becomes excessive and a charging voltage of the capacitor exceeds the withstand voltage, a part may be damaged. Therefore, regenerative power is limited due to the withstand voltage of the capacitor.

To solve such a problem, for example, patent document 1 proposes a technique of suppressing a voltage rise of a capacitor of a dc power supply circuit by driving a motor of a blower fan or a heat pump compressor mounted in a washing machine to perform a power running operation so as to consume regenerative electric power. Patent document 2 describes a technique of supplying a current having a high frequency component to the d-axis of the motor to generate a magnetic loss, and generating regenerative power by the motor itself to decelerate in a short time.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2014-68715

Patent document 2: japanese patent laid-open publication No. 2009-153308

Disclosure of Invention

Problems to be solved by the invention

However, in the method of patent document 1, since the blower fan and the heat pump compressor, which are not required to be driven originally, are driven, driving sound (noise) is generated. Similarly, the method proposed in patent document 2 has a problem in that a high-frequency current is superimposed to consume the regenerative power, and thus a large noise is generated.

The present invention has been made to solve the above problems, and an object of the present invention is to: provided is a washing machine capable of decelerating a washing drum in a short time without generating unnecessary noise.

Means for solving the problems

In order to achieve the above object, the washing machine of the present invention includes an outer tub, a washing tub disposed in the outer tub, a motor (e.g., motor M) for supplying a rotational force to the washing tub, a first control unit for controlling the motor, a linear actuator (linear actuator) connected to the outer tub, a second control unit for controlling the linear actuator, and a dc power supply common to the first control unit and the second control unit, wherein the second control unit controls a current flowing through the linear actuator so that a length of the linear actuator is shortened or lengthened during a deceleration operation of the motor. Other embodiments of the present invention will be described in the following embodiments.

Effects of the invention

According to the invention, the washing drum can be decelerated in a short time without generating unnecessary large noise.

Drawings

Fig. 1 is a perspective view of a drum type washing machine in a first embodiment.

Fig. 2 is a longitudinal sectional view of the washing machine of the first embodiment.

Fig. 3 is a block diagram of an electric circuit of the washing machine controller of the first embodiment.

Fig. 4 is a detailed configuration diagram of an electric circuit of the washing machine controller of the first embodiment.

Fig. 5 is a cross-sectional view of the linear actuator of fig. 2.

Fig. 6 is a schematic diagram of the linear actuator of fig. 2.

Fig. 7 is a graph showing a relationship between a current and a speed at the time of regeneration of the linear actuator according to the first embodiment.

Fig. 8 is a schematic diagram of a regenerative operation during deceleration of the motor according to the first embodiment.

Fig. 9 is a phase diagram of current versus speed for the single phase linear actuator of the first embodiment.

Fig. 10 is an operation diagram of the washing machine of the first embodiment.

Fig. 11 is a flowchart of the dehydration step of the first embodiment.

Fig. 12 is a graph of the relationship between current and speed in the modification example of the first embodiment.

Fig. 13 is a flowchart of the dehydration step of the second embodiment.

Fig. 14 is a flowchart of the dehydration step of the third embodiment.

Fig. 15 is a schematic diagram of a regenerative operation during deceleration of the motor according to the fourth embodiment.

Fig. 16 is a flowchart of the dehydration step in the fifth embodiment.

Fig. 17 is a graph of current versus speed for the fifth embodiment.

Description of the reference numerals

10: a linear actuator; 11: a stator; 11 a: an iron core; 11 b: a winding; 12: a mover; 20: an elastic device; 31: a base; 32: a chassis; 35: a washing drum; 36: an elevator; 37: an outer cylinder; 38: a drive mechanism; 40: an acceleration sensor; 41: a washing machine controller; 42: a position sensor; 43: a temperature sensor (temperature detection unit); 50: a current detection unit; 103: a linear actuator; 121b, 122b, 123 b: a permanent magnet; 301: a first control unit; 302: a second control unit; 3011: a first computing device; 3012: a first inverter circuit; 3021: a second computing device; 3022: a second inverter circuit; 3023: a displacement sensor; edc: a direct current voltage; f: a direct-current power supply circuit (direct-current power supply); f1: a rectifying circuit; ih: a high frequency current; io: an offset current; m: an electric motor (motor); vs: a voltage sensor (voltage detection unit); w: a washing machine.

Detailed Description

< first embodiment >

Fig. 1 is a perspective view of a drum type washing and drying machine (hereinafter, referred to as a washing machine W) according to a first embodiment, and fig. 2 is a longitudinal sectional view of the washing machine W according to the first embodiment. Washing machine W includes base 31, cabinet 32, door 33, operation/display panel 34, and drain hose H. The base 31 supports the cabinet 32.

The casing 32 includes left and right side plates 32a, a front cover 32b, a back cover 32c (see fig. 2), and an upper cover 32 d. A circular inlet h1 (see fig. 2) for taking in and out clothes is formed near the center of the front cover 32 b. The door 33 is an openable and closable lid provided at the inlet h 1.

The operation/display panel 34 is a panel provided with an electric switch, an operation switch, a display, and the like, and is provided on the upper cover 32 d. The drain hose H is a pipe for discharging the washing water of the outer tub 37 (see fig. 2), and is connected to the outer tub 37.

In addition to the above configuration, as shown in fig. 2, the washing machine W includes a washing tub 35, a lifter 36, a drive mechanism 38 (motor M (motor)), an air blowing unit 39, and a washing machine controller 41 (microcomputer) for controlling the washing machine W.

The washing tub 35 accommodates clothes and has a bottomed cylindrical shape. The washing tub 35 is housed in the outer tub 37, and is supported by the shaft so as to be rotatable on the same shaft as the outer tub 37. A plurality of through holes (not shown) for water passage and ventilation are provided in the peripheral wall and the bottom wall of the washing tub 35. In addition, both the opening h2 of the tub 35 and the opening h3 of the outer tub 37 face the door 33 in the closed state. The lifter 36 is provided on the inner peripheral wall of the washing tub 35 to lift and lower clothes during washing and drying.

The outer cylinder 37 is a bottomed cylinder for storing washing water and the like. As shown in fig. 2, the tub 37 encloses the washing tub 35. The linear actuator 10 and the elastic device 20 are provided on the left and right sides of the outer cylinder 37 for support and shock absorption, respectively. A temperature sensor 43 (temperature detection means) is provided on the stator 11 of the linear actuator 10.

In fig. 2, one of the right and left linear actuators 10 is illustrated. The xyz axes are determined as shown in fig. 2. In addition, a direction in which the x-axis is positive is defined as left, and a negative direction is defined as right.

When the left and right linear actuators 10 are distinguished from each other, the linear actuator positioned in the left direction is 10L, and the linear actuator positioned in the right direction is 10R. A drain hole (not shown) is provided in the lowermost portion of the bottom wall of the outer tube 37, and the drain hose H is connected to the drain hole.

The drive mechanism 38 is a mechanical structure for rotating the washing tub 35, and is provided outside the bottom wall of the outer tub 37. The drive mechanism 38 is a permanent magnet motor (motor M), and a rotating shaft penetrates the bottom wall of the outer tub 37 and is connected to the bottom wall of the washing tub 35. In addition, the driving mechanism 38 is provided with a position sensor 42 for detecting the rotation speed of the washing tub 35. The air blowing unit 39 blows warm air into the washing tub 35 and is disposed above the washing tub 35.

An acceleration sensor 40 that detects the amount of vibration of the outer cylinder 37 and converts the acceleration vibration into electrical information to output is provided at an arbitrary position of the outer cylinder 37.

Although not shown, a washing machine controller 41 for controlling the washing machine W selects a washing step based on information input to the operation/display panel 34, and controls the driving mechanism 38. The washing machine controller 41 is provided with a supply power determination unit that determines that the power supply from the outlet is cut off due to a power failure or the like.

Fig. 3 is a structural diagram of the washing machine controller 41 of the first embodiment. Fig. 3 shows an example of the washing machine controller 41. In fig. 3, E is a single-phase ac power supply supplied from an outlet or the like. The ac voltage is converted into a dc voltage by a rectifier circuit F1. Here, D1 to D4 are rectifier diodes. Ch is a smoothing capacitor and has a function of reducing a ripple voltage of a dc voltage generated at the time of rectification. The smoothing capacitor is charged with electric power generated by regenerative operation during deceleration or the like. k1 is a positive power supply line of the dc power supply, k2 is a negative power supply line, and Edc is a dc voltage of the dc power supply circuit F. The direct current voltage Edc is measured using a voltage sensor Vs (voltage detection unit) or the like.

The first control unit 301 includes a first calculation device 3011 and a first inverter circuit 3012. Similarly, the second control unit 302 includes a second computing device 3021 and a second inverter circuit 3022.

A dc power supply circuit F is commonly connected to the first inverter circuit 3012 and the second inverter circuit 3022, and a dc voltage Edc is supplied thereto. PWM signals 3011P and 3021P are supplied from the respective computing devices to the first inverter circuit 3012 and the second inverter circuit 3022, and the dc voltage Edc is PWM-modulated at a cycle of the carrier frequency F _ PWM so as to be a desired voltage. The carrier frequency F _ PWM is mostly set from 1kHz to 20 kHz.

The first inverter circuit 3012 is connected to the drive mechanism 38 (motor M) via a wiring 3014, and is controlled to a desired rotation speed by applying a voltage calculated by the first calculation device 3011. The current 3011i detected by the first inverter circuit 3012 and information of the rotation angle sensor 3013 provided in the motor M are fed back to the first calculation device 3011.

The second inverter circuit 3022 is connected to the linear actuator 10 through a wiring 3024, and is controlled to have a desired vibration by applying the voltage calculated by the second calculation device 3021. The current 3021i detected by the second inverter circuit 3022 is fed back to the second computing device 3021, and information of the displacement sensor 3023 provided in the linear actuator 10 is fed back. When the displacement sensors 3023 provided in the left and right linear actuators 10 are distinguished from each other, 3023L is a displacement sensor positioned in the left direction, and 3023R is a displacement sensor positioned in the right direction.

Next, fig. 4 illustrates a second inverter circuit 3022.

Fig. 4 is a detailed configuration diagram of the circuit of the washing machine controller 41 of the first embodiment. In fig. 4, the first inverter circuit 3012 has the same configuration, and therefore, description thereof is omitted. The second inverter circuit 3022 is configured by semiconductor elements S1 to S6 formed of IGBTs or the like and a diode D. Further, a current detection means 50 is provided. The second inverter circuit 3022 controls the semiconductor devices S1 to S6 and the linear actuator 10 connected to the wiring 3024 in accordance with a PWM signal 3021P (see fig. 3) from the second computing device 3021. Fig. 4 shows an example in which 2 single-phase linear actuators 10 are connected to a three-phase second inverter circuit 3022, but when, for example, a washing machine W includes 2 three-phase linear actuators, a dc power supply of a new inverter circuit having the same configuration as the first inverter circuit 3012 may be connected in common. In washing machine W, motor M is generally a three-phase permanent magnet synchronous motor in many cases.

A linear actuator 10 using a linear motor will be described with reference to fig. 5.

Fig. 5 is a cross-sectional view of the linear actuator 10 of fig. 2. In the linear actuator 10, the stator 11 is connected to the base 31, and the mover 12 is connected to the outer cylinder 37. In fig. 5, a half of the linear actuator 10 is illustrated in the x direction, but the structure of the linear actuator 10 is symmetrical with respect to the yz plane.

The linear actuator 10 is an electric motor in which the relative position of the stator 11 and the mover 12 is linearly changed in the z direction by magnetic attraction/repulsion (i.e., thrust) in the z axis direction between the stator 11 as a motor element and the plate-shaped mover 12 extending in the z direction.

The core 11a of the stator 11 includes an annular portion and magnetic pole teeth T, and is wound with a winding 11 b. By supplying current to this winding 11b, the stator 11 functions as an electromagnet.

The mover 12 includes a plurality of metal plates 12a extending in the z direction, and

permanent magnets

121b, 122b, and 123b provided on the metal plates 12a at predetermined intervals in the z direction. Further, a plurality of permanent magnets may be bonded to the metal plate, or a plurality of permanent magnets may be embedded in the metal plate.

Fig. 6 is a schematic view of the linear actuator 10 of fig. 2. The elastic device 20 (elastic body) shown in fig. 6 is a spring that applies an elastic force to the mover 12, and is interposed between the mover 12 and the fixing jig J. As shown in fig. 5, the mover 12 penetrates the stator 11.

Next, the regeneration operation will be described.

In the present embodiment, the motor M is a permanent magnet synchronous motor driven by three-phase ac, and is driven by vector control. The vector control is a method of converting rotational coordinates of a three-phase ac current/voltage using rotational angle information acquired from a rotational angle sensor 3013 (see fig. 3) provided in the motor M, and controlling the current by a vector on a rotational coordinate system called a d-axis or a q-axis. Vector control is known as a method of driving a general three-phase motor. The rotational coordinate transformation is calculated according to equation (1).

[ equation 1]

Here, Iu, Iv, and Iw are ac currents flowing through the motor M, and can be measured by a current detection unit provided in the inverter. The rotation angle θ (rad) is information measured by the rotation angle sensor 3013. The rotational coordinate conversion and vector control shown in the formula (1) are calculated by a microcomputer or the like (not shown) provided in the first calculation device 3011.

Id. Iq is a dc current obtained by converting the rotational coordinate, Iq is referred to as a torque current for supplying a rotational force to the motor, and Id is referred to as a magnetic flux current orthogonal to Iq. When the motor M is rotated, a positive torque is generated by setting Iq to a positive value and Id to 0 or a negative value. The state where the torque is positive is referred to as "power running".

On the other hand, when accelerating the motor M, a negative torque (braking torque) can be generated by providing Iq as a negative value and Id as 0 or a negative value. This deceleration (braking) state is generally referred to as "regeneration".

During the powering operation, electric power is supplied from the first inverter circuit 3012 (see fig. 3) and consumed by the motor M. On the other hand, during regeneration, the rotational energy of the motor M is reversely supplied to the first inverter circuit 3012, and the regenerated energy is supplied to the capacitor Ch of the dc power supply circuit F. Accordingly, the voltage of the capacitor Ch rises.

Next, the power running and the regenerative operation in the case of the single-phase linear actuator 10 shown in fig. 4 will be described. In the case of the single-phase linear actuator 10, since three-phase alternating current is not used, the vector control as in the formula (1) is rarely performed. In the single-phase linear actuator 10, the current is controlled in accordance with the velocity V (m/s) which is a differential value of the displacement x (m) detected by the displacement sensor 3023. Further, control is executed by a microcomputer or the like provided in the second computing device 3021.

Fig. 7 is a graph showing a relationship between a current and a speed at the time of regeneration of the linear actuator 10 according to the first embodiment. Fig. 7 shows waveforms of a current I10 flowing through the linear actuator 10, a differential value of the displacement X detected by the displacement sensor 3023, that is, a waveform at the time of power running (fig. 7 (a)) and at the time of regenerative operation (fig. 7 (b)). Here, when a current is supplied in the same phase (or the same sign) as the speed, a thrust is generated in a direction in which the speed of the linear actuator 10 is accelerated, and thus the "power running" operation is performed. On the other hand, when the current is controlled to the phase opposite to the speed (or the opposite sign), a thrust for decelerating the speed V is generated, and therefore, the "regenerative" operation is performed. In fig. 7, a case where there is no phase delay in the relationship between the speed and the current is shown, but in actual control, a phase error may occur due to a delay of a calculation device or the like.

The relationship between the speed and the current depends on the detection polarity of the sensor for detection and the structure of the linear actuator 10. The regenerative operation can be determined based on whether or not the thrust (current) is a thrust for decelerating the speed V.

Next, the operation of the motor M during deceleration will be described with reference to fig. 8, taking the spin-drying process of the washing machine W as an example.

Fig. 8 is a schematic diagram of the regenerative operation during deceleration of the electric motor M according to the first embodiment. In the interval from time t0 to time t1, the motor M, i.e., the washing tub 35, rotates at a predetermined rated rotational speed as shown in fig. 8 (a). In this section, the motor M is powered (fig. 8 (b)). Therefore, the regeneration to the capacitor Ch is hardly performed. At this time, the q-axis current Iq of the motor M is positive (see fig. 8 (e)). The current of the linear actuator 10 depends on the state of vibration, but may be in any state of power running, regeneration, and no current supply. For simplicity, fig. 8 (c) shows the regeneration state in fig. 8 (f).

When the dehydration step is completed at time t1, the motor M starts to decelerate. During deceleration, a regenerative operation is performed with the q-axis current Iq of the motor M set to negative. At this time, the linear actuator 10 also performs the regenerative operation to suppress the vibration, and both perform the regenerative operation. Therefore, the regenerative power to the capacitor Ch becomes large. As described above, if the regenerative power becomes too large, the voltage resistance of the capacitor Ch is exceeded, and there is a possibility that the electric components are damaged. Therefore, the regenerative operation must be restricted to the withstand voltage of the capacitor Ch or less.

Here, since the linear actuator 10 suppresses the vibration of the outer cylinder 37, when the regenerative operation is restricted (that is, when the damper control is restricted), the vibration of the outer cylinder 37 becomes large, and there is a possibility that the linear actuator comes into contact with the casing 32. Therefore, the regenerative operation of the linear actuator 10 cannot be restricted greatly, and the regenerative operation of the motor M must be restricted. As a result, there is a problem in that the rotation stop time of the washing machine W must be extended.

Next, a method of supplying current to the linear actuator 10 in the regenerative operation, which is a feature of the present invention, will be described with reference to fig. 9, 10, and 11.

Fig. 9 is a phase diagram of the current versus the speed of the single-phase linear actuator 10 of the first embodiment. In the present embodiment, the features are: when the motor M is braked after the dehydration step is completed, a dc offset current Io is supplied to the linear actuator 10.

Fig. 10 is an operation diagram of the washing machine of the first embodiment. Fig. 10 schematically shows a state of washing machine W to which the present embodiment is applied. In fig. 10, C represents laundry. The linear actuator 10 is supplied with a dc offset current Io to sink the position of the outer cylinder 37.

Here, the amount of sinking xo (m) by the offset current Io can be obtained from the formula (2), and the copper loss wo (w) at this time is the formula (3).

[ formula 2]

[ formula 3]

Here, Kt (N/a) is a thrust constant per unit current of the linear actuator 10, K (N/m) is a spring constant of the elastic device 20 (elastic body), and R (Ω) is a resistance value of the linear actuator 10. The offset current Io may be set in consideration of interference with other components provided in the washing machine W, a movable range of the linear actuator 10.

In addition, not only the direction in which the linear actuator 10 sinks, but also the offset current Io may be provided in the direction in which the washing tub 35 is extended (raised).

By supplying the dc offset current Io in this way, the regenerative electric power is used as the thrust force required for the expansion and contraction of the spring. The copper loss Wo generated at this time is consumed as heat. Since the dc offset current Io only has the function of statically lowering the position of the outer tube 37, the regenerative electric power can be consumed as the copper loss Wo without impairing the damping performance of the outer tube 37.

Fig. 11 is a flowchart of the dehydration step of the first embodiment. The washing machine controller 41 rotates the motor M (step S111), determines whether or not there is a stop command for the motor M (step S112), and if there is no stop command (step S112: no), returns to step S112, and if there is a stop command (step S112: yes), stops the motor M (step S113). Then, the washing machine controller 41 supplies the offset current Io to the linear actuator 10 (step S114), and determines whether or not the motor M is stopped (step S115). If the motor M is not stopped (no in step S115), the washing machine controller 41 returns to step S115, and if the motor M is stopped (yes in step S115), the current supply to the linear actuator 10 is stopped (step S116), and the spin-drying process is ended.

The washing machine W of the present embodiment includes an outer tub 37, a washing tub 35 provided in the outer tub 37, a motor M (motor) for supplying a rotational force to the washing tub 35, a first control unit 301 for controlling the motor, a linear actuator 10 connected to the outer tub 37, a second control unit 302 for controlling the linear actuator 10, and a dc power supply circuit F common to the first control unit 301 and the second control unit 302, wherein the second control unit 302 controls a current flowing through the linear actuator 10 so as to shorten or lengthen the length of the linear actuator 10 during a deceleration operation of the motor.

< effects >

According to the first embodiment, when the motor M is braked, the linear actuator 10 is supplied with the dc offset current Io in addition to the ac current for suppressing vibration. The regenerative power can be consumed as the copper loss Wo by the offset current Io of the energization dc, and the washing tub 35 can be stopped in a short time without significantly impairing the braking operation (regenerative operation) of the motor M and the damping operation of the linear actuator 10.

Further, in the case of controlling the linear actuator 10 to be settled, the distance between the base 31 (fixing jig J) and the outer cylinder 37 can be shortened. Therefore, for example, when the outer cylinder 37 vibrates in the x-axis direction of fig. 1, the vibration of the outer cylinder 37 can be suppressed by a small damping force (regenerative electric power) in accordance with the principle of leverage.

Therefore, compared to the case where the example of the present embodiment is not implemented, the regenerative power generated by the linear actuator 10 can be suppressed, and the regenerative power can be consumed greatly by the offset current Io.

In the present embodiment, the linear actuator 10 is contracted for the purpose of preventing an excessive increase in dc voltage generated by regenerative power, but may be used for other purposes. For example, the vibration of the washing tub 35 can be realized with a smaller damping force by controlling the linear actuator 10 to contract at the time of acceleration, instead of deceleration of the dehydrating operation. Therefore, it can also be used for the purpose of reducing the vibration of the washing machine W.

On the other hand, when the linear actuator 10 is controlled in the extending direction, the thrust force required to extend the spring and the thrust force required to increase the weight of the washing tub 35 can be generated. Therefore, the regenerative power can be consumed greatly by a small displacement change of the linear actuator 10.

< modification of the first embodiment >

Fig. 12 is a graph of the relationship between current and speed in the modification example of the first embodiment. In the first embodiment, the linear actuator 10 is described as a single-phase linear actuator, but in the present modification, the operation in the case of a three-phase linear actuator 103 (not shown) will be described with reference to fig. 12. In the case of the three-phase linear actuator 103, the q-axis current Iq is controlled to a phase opposite to the speed V at the time of regeneration (at the time of damping).

Fig. 12 (a) to 12 (c) show relationships between the speed V of the linear actuator 103, the q-axis current Iq, and the phase currents Iu, Iv, and Iw when the offset current Io is not supplied. When regeneration (braking) is performed in the three-phase linear actuator 103, as shown in fig. 12 (c), phase currents Iu, Iv, and Iw centered around OA flow.

On the other hand, in the first embodiment, the offset current Iqo is supplied to the q-axis current in order to consume the regenerative power by the copper loss Wo. Fig. 12 (d) to 12 (f) show waveforms thereof. The phase current waveform when the offset current Io is supplied is an ac waveform offset from OA as shown in fig. 12 (f).

< effects >

According to the modification of the first embodiment, the washing tub 35 can be stopped in a short time without significantly impairing the braking operation (regeneration operation) of the motor M and the damping operation of the linear actuator 103 even for the three-phase linear actuator 103.

In the present embodiment, the operation during deceleration in the dehydration step is described as an example, but the present invention is also applicable to deceleration operation of a motor in the washing step. For example, the present invention can be applied to a washing process and a rinsing process in which laundry is agitated by rotating the washing tub 35 in the left-right direction and in the reverse direction. When the rotation direction is reversed, the motor is decelerated in the same manner as in the dehydration step, and therefore, regenerative electric power is generated. By executing the operation described in the first embodiment by the linear actuator 10, the reverse rotation operation of the washing tub 35 can be performed as quickly as possible, and the washing process can be ended in a short time.

< second embodiment >

Fig. 13 is a flowchart of the dehydration step of the second embodiment. The second embodiment is different from the first embodiment in that whether or not the offset current Io is supplied to the linear actuator 10 is determined based on the dc voltage Edc of the capacitor Ch. The same components as those of the first embodiment are assigned the same reference numerals, and the description thereof is omitted, and different portions are described.

When a stop command is issued (step S112: yes), washing machine controller 41 performs a regenerative operation of motor M (step S133) and performs a braking operation of linear actuator 10 (step S134). Then, the washing machine controller 41 determines whether or not the voltage is equal to or less than a threshold value of the withstand voltage of the capacitor Ch (step S135), and if not equal to or less than the threshold value (step S135: no), the offset current Io is supplied to the linear actuator 10 (step S138), and the process returns to step S135. If the current is less than the threshold value (step S135: YES), the washing machine controller 41 stops the energization of the offset current Io to determine whether the motor M is stopped (step S136), returns to step S133 if the motor M is not stopped (step S136: NO), and ends the spin-drying process if the motor M is stopped (step S136: YES).

In the regeneration operation when the motor M is stopped, even if the linear actuator 10 performs the braking operation, the desired deceleration operation may be performed below the threshold of the withstand voltage of the capacitor Ch due to the mass of clothes in the washing tub 35, eccentricity, or the like. In this case, as in the first embodiment, the offset current Io may not always flow through the linear actuator 10.

The washing machine controller 41 feeds back voltage information detected by the voltage sensor Vs to the first calculation device 3011 and the second calculation device 3012, and stops the energization of the offset current Io when it is determined that the voltage information is equal to or less than the threshold value of the capacitor Ch. However, during deceleration of motor M, when the resonance frequency of washing machine W is high, the vibration increases, the regenerative power of linear actuator 10 increases, and the withstand voltage of capacitor Ch may be exceeded. For this reason, during deceleration, the dc voltage Edc of the capacitor Ch is always monitored, and it is desirable to start energization of the offset current Io when a predetermined threshold value is just about to be exceeded. Further, the supply of the offset current Io may be increased in stages while monitoring the dc voltage Edc. However, according to the formula (2), it is preferable not to provide the offset current Io as large as exceeding the movable range of the linear actuator 10.

The second control unit 302 may adjust the magnitude of the current flowing through the linear actuator 10 so that the length of the linear actuator 10 is shortened or lengthened, based on the detection result of the voltage sensor Vs (voltage detection means), during the deceleration operation of the motor M (motor).

When the voltage detected by the voltage detecting means is higher than the predetermined voltage, the second control unit 302 may increase the magnitude of the current to increase the shortening amount or the extending amount of the linear actuator 10.

< effects >

According to the second embodiment, the regenerative power to the capacitor Ch can be appropriately adjusted. This eliminates the need to unnecessarily pass a current through the linear actuator 10, and can suppress heat generation due to the copper loss Wo of the linear actuator 10.

< third embodiment >

Fig. 14 is a flowchart of the dehydration step of the third embodiment. The third embodiment is different from the first and second embodiments in that the magnitude of the current supplied to the linear actuator 10 is adjusted according to information of the temperature sensor 43 (refer to fig. 1) provided in the linear actuator 10. The same components as those of the first and second embodiments are assigned the same reference numerals, and the description thereof is omitted, and different portions are described.

Washing machine controller 41 determines whether or not capacitor Ch is equal to or less than a threshold value smaller than the withstand voltage (step S135), and if not equal to or less than the threshold value (step S135: no), determines whether or not linear actuator 10 is equal to or less than a predetermined temperature based on information from temperature sensor 13 (see fig. 1) (step S137). When the temperature of the linear actuator 10 is equal to or lower than the predetermined temperature (yes in step S137), the washing machine controller 41 supplies the offset current Io to the linear actuator 10 (step S138), and returns to step S135.

When the linear actuator 10 is not at the predetermined temperature or lower (no in step S137), the washing machine controller 41 reduces the offset current Io to the linear actuator 10 as compared with the case of step S138 to supply the current (step S139), and returns to step S135.

According to the first and second embodiments, when regenerative power is consumed by copper loss Wo in linear actuator 10, heat generation occurs. If the winding 11b, the permanent magnet 121b, or the like provided in the linear actuator 10 becomes high in temperature, insulation failure, demagnetization, or the like may occur, and the function as the linear actuator 10 may be lost. Therefore, it is preferable to set the temperature to a predetermined upper limit temperature or lower.

For this reason, the present embodiment is characterized in that: the magnitude of the offset current Io supplied to the linear actuator 10 is made variable in accordance with the temperature of the linear actuator 10.

The third embodiment includes the temperature sensor 43 (temperature detection means) for detecting the temperature of the linear actuator 10, and the second control unit 302 can adjust the magnitude of the current flowing through the linear actuator 10 based on the temperature detected by the temperature detection means and the detection result of the voltage detection means.

In addition, the second control unit 302 may reduce the magnitude of the current flowing through the linear actuator 10 when the temperature detected by the temperature detection means is higher than the predetermined temperature.

< effects >

According to the third embodiment, the regenerative power can be appropriately adjusted according to the temperature of the linear actuator 10. This can appropriately adjust the regenerative power while preventing damage and deterioration of the linear actuator 10.

< fourth embodiment >

Fig. 15 is a schematic diagram of a regenerative operation during deceleration of the electric motor M according to the fourth embodiment. The fourth embodiment is different from the first, second, and third embodiments in the manner of supplying the offset current Io to the left and right linear actuators 10. The same components as those of the first, second, and third embodiments are denoted by the same reference numerals, and descriptions thereof are omitted, and different portions are described.

Since the washing machine W rotates in one direction during deceleration, the damping (regeneration) control required for the

linear actuators

10L and 10R provided on the left and right sides is different. For example, as shown in fig. 10, when the washing tub 35 is rotated counterclockwise, the vibration of the linear actuator 10L becomes large, and thus the regenerative power becomes large. On the other hand, the linear actuator 10 provided on the right side has relatively small vibration, and the damping control may not be performed. In order to give priority to damping (regeneration) control of one of the left and right linear actuators 10 in limited regenerative power consumption capacity, one of the linear actuators 10 is controlled to supply only the offset current Io. Fig. 15 (c) shows a current waveform when the offset current Io is supplied to the left linear actuator 10L when damping control is performed, as in the first embodiment, and fig. 15 (d) shows a case where damping control of the right linear actuator 10R is stopped and only the offset current Io is supplied. In fig. 15 (d), the regeneration current is consumed by the copper loss Wo during deceleration.

The washing machine W according to the fourth embodiment includes at least 2 or more linear actuators 10, and the second control unit 302 can independently control the magnitude of the current supplied to the linear actuators 10.

< effects >

According to the fourth embodiment, the control of the offset current Io and the damping supplied to the linear actuators 10 provided on the left and right is performed independently on the left and right in correspondence with the rotation direction. This makes it possible to efficiently consume regenerative power from the motor M and the linear actuator 10L while suppressing regenerative power from the linear actuator 10R, and to realize deceleration of the motor M in a short time with limited regenerative power consumption capability.

< fifth embodiment >

Fig. 16 is a flowchart of the dehydration step in the fifth embodiment. The fifth embodiment differs from the first to fourth embodiments in that high-frequency electric power is superimposed on the linear actuator 10. The same components as those of the first to fourth embodiments are assigned the same reference numerals, and the description thereof is omitted, and different portions will be described.

Washing machine controller 41 determines whether or not the threshold value of capacitor Ch that is smaller than the withstand voltage is equal to or smaller than the threshold value (step S135), and if not equal to or smaller than the threshold value (step S135: no), determines whether or not the regenerative power can be consumed only by offset current Io (step S137A). If the regenerative power can be consumed only by the offset current Io (yes in step S137A), the washing machine controller 41 supplies the offset current Io to the linear actuator 10 (step S138), and returns to step S135.

If the regenerative power cannot be consumed only by the offset current Io (no in step S137A), the washing machine controller 41 supplies the offset current Io and the high-frequency current Ih to the linear actuator 10 (step S139A), and returns to step S135.

When the gap between the outer tube 37 and the casing 32 is small, the value of the offset current Io must be limited in order to prevent the outer tube 37 from contacting the casing 32 due to the expansion and contraction of the linear actuator 10 during the regenerative operation.

Fig. 17 is a graph of current versus speed for the fifth embodiment. In the present embodiment, when the value of the offset current Io is limited, the high-frequency current Ih averaging zero is superimposed on the linear actuator 10. In addition, when the regenerative power cannot be consumed only by the offset current Io, the minimum high-frequency current Ih may be superimposed. The frequency of the high-frequency current Ih is preferably equal to or less than the carrier frequency F _ PWM period. Thus, the fifth embodiment can be executed without changing the calculation cycle of the second calculation device 3021 (see fig. 3). The current Ir in the figure is, for example, a current of a U-phase (3024U) or a W-phase (3024W) in the wiring of fig. 4.

The lowest frequency of the superimposed high-frequency current is preferably set to be equal to or higher than the rotational frequency of washing machine W. For example, in the case of superimposing the high frequency current Ih that is the same as the rotational frequency (rotational speed) of the washing tub 35, the vibration of the washing tub 35 may be increased by the high frequency current Ih.

In the washing machine W, a resonance frequency of large vibration is often 10Hz (600rpm) or less. The rated revolution number in the dehydration step or the like is often set to about 20Hz (1200 revolutions). Therefore, it is desirable to set the lowest frequency to 30Hz or higher so that the superimposed current does not overlap with the rotational frequency. The superimposed frequency may be variable according to the rotational frequency of washing machine W.

In the fifth embodiment, the second control unit 302 may superimpose a high frequency current whose average is zero, in addition to controlling the current flowing through the linear actuator 10 so that the length of the linear actuator 10 is shortened or lengthened. In addition, it is characterized in that: the high frequency current is lower than the carrier frequency and higher than the vibration frequency of the washing machine.

< effects >

According to the fifth embodiment, in addition to applying the offset current Io to the linear actuator 10, the high-frequency current Ih averaging zero is applied. Accordingly, even when the gap between the outer tube 37 and the casing 32 is small, the regenerative power can be appropriately consumed. In addition, since the superimposed high-frequency current Ih can be suppressed, the generation of noise can also be suppressed.

< other embodiment >

In each embodiment, the deceleration from the start of the dehydration step is described as an example of a method of supplying the offset current Io to the linear actuator 10, but the present invention is not limited to this. For example, when the washing drum is rotated alternately in the left-hand rotation and the right-hand rotation during washing to decelerate during stirring of clothes, the offset current Io may be supplied to consume the regenerative power. This enables the stirring operation to be performed swiftly, and the washing process to be completed in a short time.

Although not shown, the magnitude of the offset current Io supplied to the right and left linear actuators may be adjusted in accordance with the temperature rise of the linear actuator 10. This prevents the linear actuator 10 from being damaged or deteriorated due to excessive temperature information, and also efficiently realizes the deceleration operation of the motor M.

The embodiments are described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to the embodiments having all the configurations described. In addition, as for a part of the configuration of the embodiment, addition, deletion, and replacement of another configuration can be performed. The above-described mechanisms and structures that are considered necessary for the description are shown, and not all of the mechanisms and structures are necessarily shown in the product.

Claims

1. A washing machine is characterized by comprising:

an outer cylinder;

a washing drum disposed in the outer drum;

a motor for providing a rotational force to the washing tub;

a first control unit that controls the motor;

a linear actuator connected to the outer cylinder;

a second control unit for controlling the linear actuator; and

a DC power supply shared by the first control part and the second control part,

the second control unit controls a current flowing through the linear actuator so that the length of the linear actuator is shortened or lengthened during a deceleration operation of the motor.

2. The washing machine as claimed in claim 1,

the washing machine comprises: a voltage detection unit for detecting the DC voltage of the DC power supply,

the second control unit adjusts the magnitude of the current according to the detection result of the voltage detection unit.

3. A washing machine according to claim 2,

the second control unit increases the magnitude of the current and increases the shortening amount or the extending amount of the linear actuator when the detected voltage of the voltage detecting unit is larger than a predetermined voltage.

4. A washing machine according to claim 2 or 3,

the washing machine comprises: a temperature detecting unit for detecting the temperature of the linear actuator,

the second control unit adjusts the magnitude of the current based on the temperature detected by the temperature detection unit and the detection result of the voltage detection unit.

5. A washing machine according to claim 4,

the second control unit reduces the magnitude of the current when the temperature detected by the temperature detection unit is higher than a predetermined temperature.

6. The washing machine as claimed in claim 1,

at least 2 linear actuators are provided,

the second control unit independently controls the magnitude of the current supplied to the linear actuator.

7. A washing machine according to claim 2,

the second control unit controls the current and superimposes a high-frequency current that is zero on average so that the length of the linear actuator is shortened or lengthened.

8. A washing machine according to claim 7,

the high frequency current is lower than the carrier frequency and higher than the vibration frequency of the washing machine.