CN112583324B - Vibration control device and washing machine - Google Patents

Abstract

The invention provides a low-cost vibration damping device and the like which can properly restrain vibration of a vibration damping object. A vibration damping device (100) is provided with: a linear motor (10) connected to the vibration reduction object (G); an inverter (40) that drives the linear motor (10); a current detector (50) that detects a current that is supplied to the linear motor (10); and a thrust adjustment unit (60) that adjusts the thrust of the linear motor (10) by driving the inverter (40) based on the current detected by the current detector (50). Thus, the vibration of the vibration reduction object (G) can be appropriately suppressed.

Description

Vibration control device and washing machine

This application is a divisional application; the application number of the parent application is "2017106674463", and the name of the invention is "Vibration control device and washing machine".

Technical Field

The present invention relates to a vibration control device for controlling the vibration of an object, etc.

Background technique

As a device including a linear actuator, for example, Patent Document 1 describes a linear compressor that compresses gas by moving a piston in a cylinder using a linear actuator.

Patent Document 2 describes a vibration control system including a position sensor for detecting the relative position of a mover of a linear actuator and a control device for controlling vibration of an object based on a detection value of the position sensor.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Publication No. 2003-214353

Patent Document 2: Japanese Patent Application Publication No. 2010-78075

Summary of the invention

In the technology described in Patent Document 1, the motor constant of the linear actuator is automatically tuned so that the piston of the linear compressor reciprocates between the top dead center and the bottom dead center without excess or deficiency. That is, the technology described in Patent Document 1 keeps the amplitude of the linear actuator constant even if various conditions change, and does not change the amplitude all the time.

Furthermore, in the technology described in Patent Document 2, since a position sensor for detecting the relative position of a mover of the linear actuator is provided, this may lead to an increase in manufacturing cost.

Therefore, an object of the present invention is to provide a low-cost vibration control device or the like that can appropriately control the vibration of an object.

In order to solve the above-mentioned problems, the present invention is characterized in that it comprises: a linear actuator connected to an object; a converter that drives the above-mentioned linear actuator; a current detector that has a current detection unit that detects the current supplied to the above-mentioned linear actuator; and a thrust adjustment unit that adjusts the thrust of the above-mentioned linear motor by driving the above-mentioned converter according to the current detected by the above-mentioned current detector.

Effects of the Invention

According to the present invention, a low-cost vibration control device and the like that can appropriately control the vibration of an object are provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view of a linear actuator included in a vibration control device according to a first embodiment of the present invention.

FIG. 2 is an end view taken along line II-II of FIG. 1 .

FIG. 3 is a perspective view of the vibration control device according to the first embodiment of the present invention.

FIG. 4 is a perspective view of a washing machine including the vibration control device according to the first embodiment of the present invention.

5 is a longitudinal sectional view of a washing machine including the vibration control device according to the first embodiment of the present invention.

FIG. 6 is a structural diagram of a vibration control device according to a first embodiment of the present invention.

FIG. 7 is a diagram showing a structure including a converter included in the vibration control device according to the first embodiment of the present invention.

FIG. 8 is an overall control block diagram including a thrust adjustment unit and the like of the vibration control device according to the first embodiment of the present invention.

FIG. 9 is a control block diagram equivalent to the primary delay element (1/(R+sL)) shown in FIG. 8 .

FIG. 10 is a structural diagram of a vibration control device according to a second embodiment of the present invention.

11 is a control block diagram of a thrust adjustment unit included in the vibration control device according to the second embodiment of the present invention.

FIG. 12A is an experimental result showing changes in the rotation speed of the washing tub and the displacement of the outer tub in a comparative example using a hydraulic damper with a fixed viscosity coefficient.

FIG. 12B is an experimental result showing changes in the rotation speed of the washing tub and the displacement of the outer tub in the second embodiment of the present invention.

FIG. 13 is a structural diagram of a vibration control device according to a third embodiment of the present invention.

14 is a control block diagram including a thrust adjustment unit and a speed information estimation unit included in the vibration control device according to the third embodiment of the present invention.

15A is an explanatory diagram showing an example of a function used when generating a current command i* based on an induced voltage Em in the vibration control device according to the third embodiment of the present invention.

15B is an explanatory diagram showing another example of the function used when generating the current command i* based on the induced voltage Em in the vibration control device according to the third embodiment of the present invention.

15C is an explanatory diagram showing another example of the function used when generating the current command i* based on the induced voltage Em in the vibration control device according to the third embodiment of the present invention.

15D is an explanatory diagram showing another example of the function used when generating the current command i* based on the induced voltage Em in the vibration control device according to the third embodiment of the present invention.

FIG. 16 is a structural diagram of a vibration control device according to a fourth embodiment of the present invention.

17 is a control block diagram including a thrust adjustment unit included in the vibration control device according to the fourth embodiment of the present invention.

FIG. 18 is a structural diagram of a vibration control device according to a modified example of the present invention.

FIG. 19A is a structural diagram of a vibration control device according to a fifth embodiment of the present invention.

FIG. 19B shows the result of thrust generated when a fixed exciting force is applied in the first embodiment.

FIG. 19C shows the result of thrust generated when a fixed exciting force is applied in the fifth embodiment.

FIG. 20 is a structural diagram of a vibration control device according to a sixth embodiment of the present invention.

21 is a control block diagram including a thrust adjustment unit and a speed information estimation unit included in the vibration control device according to the sixth embodiment of the present invention.

22A is an explanatory diagram showing an example of a function used when generating a current command i** based on an induced voltage Em in the vibration control device according to the sixth embodiment of the present invention.

22B is an explanatory diagram showing another example of the function used when generating the current command i** based on the induced voltage Em in the vibration reduction device according to the sixth embodiment of the present invention.

22C is an explanatory diagram showing another example of the function used when generating the current command i** based on the induced voltage Em in the vibration reduction device according to the sixth embodiment of the present invention.

22D is an explanatory diagram showing another example of the function used when generating the current command i** based on the induced voltage Em in the vibration reduction device according to the sixth embodiment of the present invention.

23A shows the results of the vibration speed in the vertical direction of the outer tank and the current supplied to the linear actuator 10 when the washing tub 35 is rotated at 900 (min ^-1 ) with a weight of 600 g fixed at a predetermined offset position in the washing tub 35 in the third embodiment of the present invention.

23B shows the results of the vibration speed in the vertical direction of the outer tank and the current supplied to the linear actuator 10 when the washing tub 35 is rotated at 900 (min ^-1 ) with a weight of 600 g fixed at a predetermined offset position in the washing tub 35 in the sixth embodiment of the present invention.

FIG. 24 is a structural diagram of a vibration control device according to a seventh embodiment of the present invention.

25 is a control block diagram including a thrust adjustment unit included in the vibration control device according to the seventh embodiment of the present invention.

FIG. 26A is a structural diagram of a vibration control device according to an eighth embodiment of the present invention.

FIG. 26B is a structural diagram of a vibration control device according to an eighth embodiment of the invention.

FIG. 27A is a structural diagram of a vibration control device according to an eighth embodiment of the present invention.

FIG. 27B is a structural diagram of a vibration control device according to an eighth embodiment of the invention.

In the figure: 100, 100A, 100B, 100C, 100D—vibration control device, 10—linear actuator, 10L—linear actuator (linear actuator on one side), 10R—linear actuator (linear actuator on the other side), 11—stator, 11a—core, 11b—coil, 12—motor, 121b, 122b, 123b—permanent magnet, 20—spring, 31—base, 32—housing, 32a—left and right side plates, 32b—front cover, 32c—back cover, 32d—upper cover, 33—door, h1—inlet, h2—opening h2 of washing tank 35, h3—opening h3 of washing tank 37, 34—operation and display panel, H—drain hose, 35—washing tank, 36—elevator, 37—outer tank (object) ), 38—driving mechanism, 38a—motor driving converter, 38b—motor, 39—air supply unit, 40, 40L, 40R—converter, 50—current detector, F—rectifier circuit, F1—diode bridge circuit, E—AC power supply, D1, D2, D3, D4—diode, k1—wiring, k2—wiring, S1, S2, S3, S4, S5, S6, S11, S12, S13, S14—switching element, D—freewheeling diode, Ch—smoothing capacitor, 60, 60A, 60B, 60C, 60E—thrust adjustment unit, 61, 61A—arithmetic unit, Ke—induced voltage constant, 70B, 70C—speed information estimation unit, G—object, W—washing machine, C—viscosity coefficient of linear actuator 10, F _D —damping force of the linear actuator, _FL —thrust of the linear actuator, 62, 66, 66E—table, 70B, 70C—speed information estimation unit, 63—subtractor, 65, 65C, 67, 67, 67E—current command generation unit, 64—ACR, 260A, 260B, 260C, 270A—power-on voltage and power-on current.

Detailed ways

In each of the following embodiments, a configuration in which vibration of a washing machine W (see FIG. 4 ) is controlled by a linear actuator 10 (see FIG. 1 ) will be described as an example.

(First Embodiment)

FIG. 1 is a longitudinal sectional view of a linear actuator 10 included in a vibration control device.

In addition, the xyz axis is defined as shown in Fig. 1. In Fig. 1, half of the linear actuator 10 is shown in the x direction, and the structure of the linear actuator 10 is symmetrical with respect to the yz plane.

The linear actuator 10 is a motor that linearly changes the relative position of the stator 11 and the mover 12 along the z-direction by the magnetic attraction/repulsion (i.e., thrust) in the z-axis direction between the stator 11 as an armature and the plate-shaped mover 12 extending along the z-direction. As shown in FIG. 1 , the linear actuator 10 is connected to the outer tank 37 (object) of the washing machine W (see FIG. 5 ). Specifically, the mover 12 of the linear actuator 10 is connected to the outer tank 37.

As shown in Fig. 1 , the linear actuator 10 includes a stator 11 and a mover 12. The stator 11 includes a core 11a formed by stacking electromagnetic steel sheets in the z direction, and a coil 11b wound around the magnetic pole teeth T of the core 11a.

Fig. 2 is an end view taken along line II-II of Fig. 1. Fig. 2 shows the entire linear actuator 10, not the half of the linear actuator 10 in the x direction (see Fig. 1).

As shown in FIG. 2 , the core 11 a of the stator 11 includes an annular portion S and magnetic pole teeth T, T.

The annular portion S is annular (rectangular frame-shaped) in a longitudinal cross-sectional view, and a magnetic circuit is formed by the annular portion S. A pair of magnetic pole teeth T and T extend inward in the y direction from the annular portion S and face each other. In addition, the distance between the magnetic pole teeth T and T is slightly longer than the thickness of the plate-shaped mover 12. Coils 11b are respectively wound around the magnetic pole teeth T and T. By energizing the coils 11b, the stator 11 functions as an electromagnet.

1 , two pairs of magnetic pole teeth T are provided in the z direction (moving direction of the mover 12 ). The coils 11 b wound around the two pairs of magnetic pole teeth T form one coil, and both ends thereof are connected to the output side of the inverter 40 (see FIG. 6 ) described later.

The mover 12 shown in FIG2 penetrates the annular core 11a and extends in the z direction. In addition, as shown in FIG1, 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. In addition, a plurality of permanent magnets may be attached to a single metal plate, or a plurality of permanent magnets may be buried in a single metal plate.

The permanent magnets 121b, 122b, and 123b shown in FIG1 are magnetized in the y direction. To explain in more detail, the permanent magnets magnetized toward the positive side of the y direction (for example, permanent magnets 121b and 123b) and the permanent magnets magnetized toward the negative side of the y direction (for example, permanent magnet 122b) are alternately arranged in the z direction. Moreover, a thrust in the z direction is applied to the mover 12 by the attraction/repulsion between the mover 12 and the stator 11 acting as an electromagnet. In addition, the "thrust" is a force that changes the relative position of the mover 12 and the stator 11.

In addition, it is desirable to use samarium-iron-nitrogen permanent magnets as the permanent magnets 121b, 122b, and 123b. The specific ratio (%) of the raw materials of the permanent magnets 121b, 122b, and 123b is, for example, iron: about 73%, samarium: about 24%, and nitrogen: about 3%. Among the above raw materials, the rare earth element is samarium.

In contrast, conventional neodymium magnets often use a ratio of about 65% iron, about 28% neodymium, about 5% dysprosium, and about 2% boron. Among the above raw materials, the rare earth elements are neodymium and dysprosium. Therefore, the ratio of rare earth elements in the samarium-iron-nitrogen permanent magnets 121b, 122b, and 123b is smaller than that in conventional neodymium magnets, and therefore, it is less likely to be affected by market trends and has the advantage of being able to be stably supplied.

Furthermore, unlike the existing neodymium magnets and ferrite magnets, the samarium-iron-nitrogen permanent magnets 121b, 122b, and 123b can be mixed with resin and molded. Therefore, compared with the past, the processing accuracy of the permanent magnets 121b, 122b, and 123b can be improved and their dimensional deviation can be reduced. In addition, even if there is a waste of raw materials left during molding, it can be reused, so there is no loss of raw materials and the manufacturing cost can be reduced.

FIG. 3 is a perspective view of a vibration control device 100 including the linear actuator 10 .

Vibration control device 100 is an electromagnetic suspension including linear actuator 10 and spring 20 described above, and has a function of controlling vibration of outer tub 37 as an “object” (ie, vibration of washing machine W: see FIG. 5 ).

As shown in FIG3 , one end of the mover 12 of the linear actuator 10 is connected to the outer tank 37 of the washing machine W (see FIG5 ), and the other end is connected to the fixing fixture J. In addition, the stator 11 of the linear actuator 10 is not shown in the figure, and its movement is restricted by another fixing fixture (not shown). Therefore, if the outer tank 37 of the washing machine W vibrates in the z direction, the mover 12 reciprocates in the z direction, and the relative positional relationship between the mover 12 and the stator 11 changes.

The spring 20 is a spring that applies elastic force to the stator 11 , and is interposed between the stator 11 and the fixing jig J. As shown in FIG. 3 , the mover 12 penetrates the stator 11 and also penetrates the spring 20 .

FIG. 4 is a perspective view of a washing machine W including the vibration control device 100 .

In addition, the vibration control device 100 is provided inside the washing machine W (see FIG. 5 ), and therefore, the vibration control device 100 is not shown in FIG. 4 .

The washing machine W shown in FIG4 is a drum type washing machine and also has a function of drying clothes. The washing machine W includes the vibration control device 100 (see FIG5 ), a base 31 , a housing 32 , a door 33 , an operation and display panel 34 , and a drain hose H.

The base 31 supports the box body 32 .

The box body 32 includes left and right side plates 32a, 32a, a front cover 32b, a back cover 32c (see FIG5 ), and an upper cover 32d. A circular inlet h1 (see FIG5 ) for taking out and putting in clothes is formed near the center of the front cover 32b.

The door 33 is an openable and closable cover provided at the above-mentioned input port h1.

The operation and display panel 34 is a panel provided with electric switches, operation switches, a display, etc., and is provided on the upper cover 32d.

Drain hose H is a hose for draining wash water from outer tank 37 (see FIG. 5 ), and is connected to outer tank 37 .

FIG. 5 is a longitudinal sectional view of a washing machine W including the vibration control device 100 .

In addition to the above-described structure, the washing machine W further includes a washing tub 35 , an elevator 36 , an outer tub 37 , a driving mechanism 38 , and an air blowing unit 39 .

The washing tank 35 is a cylindrical bottomed tank for storing clothes. The washing tank 35 is surrounded by an outer tank 37 and is supported by an axis rotatably coaxially with the outer tank 37. The peripheral wall and bottom wall of the washing tank 35 are provided with many through holes (not shown) for water flow and ventilation. In addition, the opening h2 of the washing tank 35 and the opening h3 of the outer tank 37 face the closed door 33 together.

5 , the central axis of rotation of the washing tub 35 is inclined so that the opening side is higher, but the present invention is not limited thereto. That is, the central axis of rotation of the washing tub 35 may be horizontal or vertical.

The lift 36 is provided on the inner peripheral wall of the washing tub 35, and lifts and lowers the clothes during washing and drying.

The outer tank 37 is used for storing washing water and is in the shape of a bottomed cylinder. As shown in FIG5 , the outer tank 37 surrounds the washing tank 35. Linear actuators 10 (stator 11, mover 12) and springs 20 are provided on the left and right sides of the outer tank 37, respectively. In addition, FIG5 shows one side of the left and right linear actuators 10.

In addition, a drain hole (not shown) is provided at the lowest part of the bottom wall of the outer tank 37, and a drain hose H is connected to the drain hole. When a drain valve (not shown) provided on the drain hose H is in a closed valve state, the washing water is stored in the outer tank 37, and when the drain valve is opened, the washing water is discharged.

Driving mechanism 38 is a mechanism for rotating washing tub 35 and is provided outside the bottom wall of outer tub 37. The rotating shaft of motor 38b (see FIG. 7 ) provided in driving mechanism 38 passes through the bottom wall of outer tub 37 and is connected to the bottom wall of washing tub 35.

The air supply unit 39 supplies hot air to the washing tub 35 and is disposed on the upper side of the washing tub 35. The air supply unit 39 includes a heater (not shown) and a fan (not shown). The air heated by the heater is supplied to the washing tub 35 by the fan. Thus, the clothes containing water are gradually dried in the washing tub 35.

Fig. 6 is a structural diagram of the vibration control device 100. Fig. 6 shows one of the two linear actuators 10 on the left and right, and omits the other. The object G shown in Fig. 6 is an outer tub 37 (see Fig. 5) of a washing machine W (see Fig. 5).

The vibration control device 100 includes an inverter 40 , a current detector 50 , and a thrust adjustment unit 60 in addition to the above-described configuration (the linear actuator 10 and the spring 20 : see FIG. 3 ).

The inverter 40 is a inverter that converts the DC voltage applied from the rectifier circuit F into a single-phase AC voltage based on the voltage command V* from the thrust adjustment unit 60, and applies the single-phase AC voltage to the coil 11b of the linear actuator 10 (see FIG. 2 ). That is, the inverter 40 has a function of driving the linear actuator 10 based on the voltage command V*.

In addition, the “DC power supply” that applies a DC voltage to the converter 40 includes an AC power supply E and a rectifier circuit F.

FIG. 7 is a diagram showing a structure including converter 40 included in vibration control device 100 .

In addition, in FIG. 7 , the linear actuator on the left side is referred to as “linear actuator 10L”, and the linear actuator on the right side is referred to as “linear actuator 10R”.

The rectifier circuit F shown in Fig. 7 is a well-known voltage-doubling rectifier circuit that converts an AC voltage applied from an AC power source E into a DC voltage. As shown in Fig. 7 , the rectifier circuit F includes a diode bridge circuit F1 formed by bridge-connecting diodes D1 to D4 and two smoothing capacitors Ch connected in series.

Then, the voltage (DC voltage including pulsating current) applied from the diode bridge circuit F1 is smoothed by the smoothing capacitor Ch, and a DC voltage equivalent to approximately twice the voltage of the AC power source E is generated.

Rectifier circuit F is connected to inverter 40 via positive wiring k1 and negative wiring k2, and is also connected to inverter 38a of drive mechanism 38 for rotating washing tub 35 (see FIG. 5 ). Drive mechanism 38 includes motor drive inverter 38a and motor 38b.

The inverter 40 is a three-phase full-bridge inverter that converts a DC voltage applied from the above-mentioned “DC power supply” into a single-phase AC voltage and applies the single-phase AC voltage to the coil 11 b (see FIG. 2 ) of the linear actuators 10L and 10R.

As shown in FIG7 , the converter 40 has a structure in which the first leg of the switch elements S1 and S2, the second leg of the switch elements S3 and S4, and the third leg of the switch elements S5 and S6 are connected in parallel. As these switch elements S1 to S6, for example, IGBT (Insulated Gate Bipolar Transistor) can be used. A freewheeling diode D is connected in anti-parallel to each of the switch elements S1 to S6.

The connection point of the switching elements S1 and S2 is connected to the coil 11b (see FIG. 2 ) of the linear actuator 10L via the wiring k3. That is, the leg corresponding to one of the three-phase inverters 40 is connected to the left (one) linear actuator 10L.

The connection point of the switching elements S5 and S6 is connected to the coil 11b (see FIG. 2 ) of the linear actuator 10R via the wiring k5. That is, the other leg corresponding to one of the three-phase inverters 40 is connected to the right (other) linear actuator 10L.

In addition, the connection point of the switching elements S3 and S4 is connected to the coil 11b (see FIG. 2) of the linear actuator 10L via the wiring k4, and is also connected to the coil 11b of the linear actuator 10R via the wiring k4. In other words, the remaining legs of the three-phase converter 40 are connected to the linear actuator 10L on the left side (one side) and the linear actuator 10R on the right side (the other side).

In this way, instead of providing inverters for the left and right linear actuators 10L and 10R, respectively, a single inverter 40 is used for both the left and right linear actuators, thereby reducing the cost of the inverter 40. Furthermore, by controlling the on-off of the switching elements S1 to S6 based on PWM control (Pulse Width Modulation), a single-phase AC voltage is applied to the coils 11b (see FIG. 2 ) of the linear actuators 10L and 10R.

The current detector 50 detects the current flowing through the linear actuators 10L and 10R and is provided in the wiring k6. That is, the current flowing through the coil 11b (see FIG. 2 ) of the linear actuators 10L and 10R is detected by the current detector 50. The wiring k6 is a wiring that connects the transmitters of the switching elements S2, SS4, and S6 and the input side of the converter 38a.

6 is not shown, but includes electronic circuits such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various interfaces, etc. The program stored in the ROM is read out and expanded to the RAM/CPU to execute various processes.

The thrust adjustment unit 60 has the function of adjusting the thrust of the linear actuator 10 by driving the converter 40 based on the current i detected by the current detector 50. That is, the thrust adjustment unit 60 generates a predetermined voltage command V* based on the above-mentioned current, and switches the switching elements S1 to S6 on and off based on the voltage command V*. The details will be described later. If the relative position of the mover 12 and the stator 11 changes due to the vibration of the outer groove 37 (refer to FIG. 5), the thrust adjustment unit 60 adjusts the thrust of the linear actuator 10 to offset the change.

Here, the vibration of the outer tank 37 (i.e., the vibration of the washing machine W) is briefly described. During washing/rinsing/drying, the washing tank 35 rotates at a low speed by the driving mechanism 38 shown in FIG5, and repeatedly performs a tumbling operation of lifting the clothes accumulated at the bottom of the washing tank 35 by the elevator 36 and dropping them. In addition, during dehydration, the washing tank 35 rotates at a high speed, and centrifugal dehydration is performed to throw out the water of the clothes by the centrifugal force of the rotation.

In addition, in conventional washing machines, the amplitude of the vibration of the washing tub 35 is often increased due to the reaction force of the falling clothes during washing/rinsing/drying. In addition, in conventional washing machines, the positional deviation of the clothes during dehydration often causes vibration and noise in the washing machine W. Thus, the vibration pattern of the washing machine W changes all the time depending on the amount of clothes in the washing tub 35, the positional deviation, the moisture content, and other conditions such as washing/rinsing/drying/dehydration. The vibration is propagated to the outer tub 37.

FIG. 8 is an overall control block diagram including the thrust adjustment unit 60 and the like.

As shown in Fig. 8 , the thrust adjustment unit 60 includes a calculation unit 61. The calculation unit 61 has a function of calculating a voltage command V* of the inverter 40 by multiplying the current i detected by the current detector 50 by a predetermined current proportional gain Kp.

The value of the current i increases as the speed of the mover 12 (see FIG. 3 ) of the linear actuator 10 increases. Therefore, the thrust adjustment unit 60 adjusts the voltage command V* to increase the current i (ie, to reduce the speed of the mover 12 connected to the outer slot 37).

By controlling the inverter 40 based on the voltage command V*, a predetermined voltage V is applied to the coil 11b (see FIG. 2 ) of the linear actuator 10. The process until the voltage V is reflected to the speed of the mover 12 (in FIG. 8 , it is indicated by adding a “·” to “x”) is shown in the frame Q. In addition, x(m) is the position of the mover 12.

That is, a voltage (V-Em) obtained by subtracting the induced voltage Em of the linear actuator 10 from the voltage V on the output side of the converter 40 is applied to the coil 11b. A predetermined current i flows through the coil 11b through the voltage (V-Em) and the first-order delay element (1/(R+sL)) based on the resistance R and the inductance L of the coil 11b. The value obtained by multiplying the current i by the motor constant Kt (also called "thrust constant") representing the characteristics of the linear actuator 10 becomes the thrust of the linear actuator 10. That is, a thrust is generated to move the relative position of the stator 11 and the mover 12 in the z direction. Moreover, due to the above-mentioned thrust and the integral element (1/sM), the speed of the mover 12 changes. In addition, M is the mass of the outer tank 37.

In addition, an induced voltage Em is generated in the coil 11b (see FIG. 2 ) of the linear actuator 10. The induced voltage Em is equal to the value obtained by multiplying the velocity of the mover 12 by the induced voltage constant Ke. The induced voltage Em changes all the time due to the vibration of the outer tank 37, and the current i flowing in the coil 11b also changes accordingly. Based on the current i, the thrust adjustment unit 60 adjusts the thrust of the linear actuator 10 to control the vibration of the outer tank 37.

For example, when the outer tub 37 vibrates, the mover 12 (see FIG. 3 ) moves upward in the z direction, and the thrust adjustment unit 60 generates a downward thrust that suppresses the movement of the mover 12 (i.e., the vibration of the outer tub 37) in the linear actuator 10. On the other hand, when the mover 12 moves downward in the z direction, the thrust adjustment unit 60 generates an upward thrust that suppresses the movement of the mover 12 in the linear actuator 10. As a result, the vibration of the outer tub 37 is suppressed, and thus the vibration of the washing machine W is suppressed.

(Effect)

According to the first embodiment, the thrust adjustment unit 60 generates thrust to cancel the vibration of the outer tank 37 based on the current i flowing through the linear actuator 10. Thus, the vibration control device 100 can appropriately suppress the vibration of the outer tank 37 by a relatively simple method.

In addition, according to the first embodiment, since it is not necessary to provide a position sensor for detecting the position of the mover 12, it is possible to reduce the cost of the washing machine W. In addition, since the linear actuator 10 hardly causes damage or wear to its structural elements (stator 11, mover 12), it is possible to improve the durability of the vibration control device 100.

The single-phase AC voltage applied to the left and right linear actuators 10L and 10R (see FIG. 7 ) is generated by one inverter 40. Therefore, the cost of the washing machine W can be reduced compared with a configuration in which inverters are provided corresponding to the left and right linear actuators 10L and 10R.

Furthermore, by using samarium-iron-nitrogen-based permanent magnets 121b, 122b, 123b (see FIG. 1 ), as described above, the cost of the permanent magnets 121b, 122b, 123b can be reduced compared to the conventional technology using neodymium magnets. Therefore, the manufacturing cost of the washing machine W can be reduced.

(Modification of the first embodiment)

In the first embodiment, the current proportional gain Kp in the thrust adjustment unit 60 is described as being fixed, but the viscosity coefficient C (Ns/m) of the linear actuator 10 may be changed by changing the magnitude of the current proportional gain Kp. A method of changing the viscosity coefficient C will be described.

The motion equation of the vibration control device 100 as an electromagnetic suspension is expressed by the following equation (1). FD(N) shown in equation (1) is the force generated by the vibration control device 100 (ie, the damping force generated by the linear actuator 10).

(Formula 1)

In addition, the motion equation of the thrust of the linear actuator 10 is expressed by equation (2). In addition, _FL (N) is the thrust of the linear actuator 10, and Kt (N/A) is the motor constant of the linear actuator 10. In addition, i (A) is the current flowing in the coil 11b (refer to FIG. 2), and V (V) is the voltage applied to the coil 11b. In addition, R (Ω) is the resistance of the coil 11b, and φ (T) is the magnetic flux generated by the coil 11b.

(Formula 2)

Here, since the damping force FD of the equation (1) and the thrust _FL of the equation (2) are equivalent, the following equation (3) can be derived. In addition, C (Ns/m) is the viscosity coefficient of the linear actuator 10.

(Formula 3)

FIG. 9 is a control block diagram equivalent to the primary delay element (1/(R+sL)) shown in FIG. 8 .

For example, if the magnitude of the resistor R shown in the formula (3) changes, the magnitude of the viscosity coefficient C of the linear actuator 10 also changes. In addition, the thrust adjustment unit 60 (see FIG. 8 ) changes the current proportional gain Kp, and thus can produce the same effect as when the resistor R is changed. That is, by changing the current proportional gain Kp, the viscosity coefficient C of the linear actuator 10 changes (that is, the damping rate of the vibration control device 100 changes).

In the thrust adjustment unit 60 shown in FIG8 , the current proportional gain Kp is increased as the current i detected by the current detector 50 is larger (i.e., the moving speed of the mover 12 accompanying the vibration of the outer tank 37 is larger). As a result, a larger thrust is generated by the linear actuator 10, and the vibration of the outer tank 37 can be effectively suppressed.

(Second Embodiment)

The second embodiment is different from the first embodiment in that a thrust adjustment unit 60A (see FIG. 10 ) changes the viscosity coefficient C of the linear actuator 10 based on the current i flowing through the linear actuator 10 and the vibration frequency f of the outer groove 37. The rest (the structure of the linear actuator 10 and the washing machine W, etc.) is the same as the first embodiment. Therefore, the parts different from the first embodiment will be described, and the description of the overlapping parts will be omitted.

FIG. 10 is a configuration diagram of a vibration control device 100A according to the second embodiment.

As shown in FIG. 10 , the vibration control device 100A includes the linear actuator 10 , the inverter 40 , the current detector 50 , and a thrust adjustment unit 60A.

The thrust adjustment unit 60A has a function of calculating a voltage command V* of the inverter 40 by multiplying the current i detected by the current detector 50 by a predetermined current proportional gain Kp. In addition, the thrust adjustment unit 60A has a function of reducing the current proportional gain Kp as the vibration frequency f of the outer tank 37 (object G) increases.

In addition, the vibration frequency f of the outer tub 37 is proportional to the rotation speed of the washing tub 35. Therefore, the thrust adjustment unit 60A calculates the vibration frequency f of the outer tub 37 based on the rotation frequency of the washing tub 35 input from the above-mentioned drive mechanism 38 (refer to FIG. 5). Therefore, a sensor for detecting the vibration frequency f of the outer tub 37 is not provided, so that the cost of the washing machine W can be reduced.

FIG. 11 is a control block diagram of the thrust adjustment unit 60A included in the vibration control device 100A.

As shown in FIG. 11 , the thrust adjustment unit 60 includes a calculation unit 61 and a table 62 .

The calculation unit 61 calculates the voltage command V* by multiplying the current i detected by the current detector 50 by a predetermined current proportional gain Kp.

The table 62 stores data indicating the relationship between the vibration frequency f of the outer tank 37 and the current proportional gain Kp in advance. Specifically, based on the data in the table 62, the higher the vibration frequency f of the outer tank 37, the larger the current proportional gain Kp is set to. That is, the higher the vibration frequency f of the outer tank 37, the smaller the viscosity coefficient C of the vibration control device 100A (see FIG. 10 ), and the larger the thrust generated by the linear actuator 10. Thus, the vibration of the outer tank 37 can be effectively suppressed.

Furthermore, since the vibration frequency f of outer tub 37 changes momentarily according to the weight, position, operation mode, etc. of the clothes in washing tub 35, thrust adjustment unit 60 changes current proportional gain Kp momentarily accordingly.

(Effect)

According to the second embodiment, the viscosity coefficient C of the linear actuator 10 is variably controlled based on the vibration frequency f of the outer groove 37. Therefore, the vibration of the outer groove 37 can be suppressed more effectively than in the first embodiment.

FIG. 12A is an experimental result showing changes in the rotation speed of the washing tub 35 and the displacement of the outer tub 37 in a comparative example using a hydraulic shock absorber with a fixed viscosity coefficient C. FIG.

In the experiment of FIG. 12A , 1 kg of clothing was placed at a predetermined offset position in washing tub 35 , and then washing tub 35 was rotated (the same is true for FIG. 12B ).

As shown in Fig. 12A, the amplitude of the outer tank 37 changes as the rotation speed of the washing tub 35 increases. Specifically, when the rotation speed of the washing tub 35 is increased from zero, the amplitude of the outer tank 37 temporarily decreases at a rotation speed of about 50 (min ^{-1 )} , and the amplitude of the outer tank 37 increases sharply at a rotation speed of about 100 (min-1) to reach the maximum amplitude. In addition, the amplitude of the outer tank 37 increases at a rotation speed of 105 to 170 (min ^-1 ), and the amplitude of the outer tank 37 decreases as the rotation speed of the washing tub 35 increases in the region of 200 (min ^-1 ) or more.

FIG. 12B is an experimental result showing changes in the rotation speed of washing tub 35 and the displacement (vibration) of outer tub 37 in the second embodiment.

In the experiment shown in FIG. 12B , the greater the rotation speed of the washing tub 35 (that is, the higher the vibration frequency f of the outer tub 37 ), the smaller the viscosity coefficient C of the linear actuator 10 .

As shown in FIG12B , when the rotation speed of the washing tank 35 is about 100 (min ^-1 ), the maximum amplitude of the outer tank 37 is about 5 mm, which is about half of the maximum amplitude (about 10 mm) of the comparative example shown in FIG12A . In addition, in the region where the rotation speed of the washing tank 35 is 500 (min ^-1 ) or more, the amplitude of the outer tank 37 is about 1 mm. Thus, according to the second embodiment, by variably controlling the viscosity coefficient C, the vibration of the outer tank 37 can be suppressed more effectively than in the first embodiment.

(Third Embodiment)

The third embodiment is different from the first embodiment in that a speed information estimating unit 70B (see FIG. 13 ) is provided, which estimates the induced voltage Em of the linear actuator 10 based on the current i supplied to the linear actuator 10 and the voltage command V* of the converter 40. In addition, the third embodiment is different from the first embodiment in that a thrust adjusting unit 60B (see FIG. 13 ) adjusts the thrust of the linear actuator 10 based on the induced voltage Em and the current i flowing in the linear actuator 10. In addition, other points (such as the structure of the linear actuator 10 and the washing machine W) are the same as those of the first embodiment. Therefore, the parts different from the first embodiment will be described, and the description of the overlapping parts will be omitted.

FIG. 13 is a configuration diagram of a vibration control device 100B according to the third embodiment.

As shown in FIG. 13 , the vibration control device 100B includes the linear actuator 10 , the inverter 40 , the current detector 50 , a thrust adjustment unit 60B, and a speed information estimation unit 70B.

The speed information estimation unit 70B is not shown in the figure, but is configured by electronic circuits including a CPU, a ROM, a RAM, and various interfaces. The program stored in the ROM is read and expanded in the RAM, and the CPU executes various processes.

The speed information estimation unit 70B estimates the induced voltage Em generated by the linear actuator 10 based on the current i detected by the current detector 50 and the voltage command V* of the converter 40 calculated by the thrust adjustment unit 60B. The induced voltage Em is expressed by the following equation (4). In addition, the voltage V, the resistance R, and the inductance L are as described in the first embodiment.

(Formula 4)

The speed information estimation unit 70B calculates the induced voltage Em of the linear actuator 10 based on the equation (4), and outputs the value of the induced voltage Em to the thrust adjustment unit 60B.

As shown in the following equation (5), the induced voltage Em of the linear actuator 10 is proportional to the speed of the mover 12 (that is, the speed of the vibrating outer tank 37). Therefore, the induced voltage Em can be said to be "a value equivalent to the speed of the outer tank 37".

(Formula 5)

FIG. 14 is a control block diagram including the thrust adjustment unit 60B and the speed information estimation unit 70B included in the vibration control device 100B.

The thrust adjustment unit 60B generates a predetermined voltage command V* based on the current i detected by the current detector 50 and the induced voltage Em calculated by the speed information estimation unit 70B.

As shown in FIG. 14 , the thrust adjustment unit 60B includes a subtractor 63 , an ACR 64 (Automatic current regulator), and a current command generation unit 65 .

The subtractor 63 has a function of subtracting the current i which is the detection result of the current detector 50 from the current command i* which is the calculation result of the current command generating unit 65 .

ACR 64 has a function of calculating voltage command V* so that the above-mentioned current i approaches current command i*. Then, based on voltage V* calculated by ACR 64, inverter 40 is controlled (see FIG. 13 ).

Current command generating unit 65 has a function of calculating a current command i* for inverter 40 based on the value of induced voltage Em input from speed information estimating unit 70B so as to cancel out induced voltage Em.

FIG. 15A is an explanatory diagram showing an example of a function used when generating a current command i* based on an induced voltage Em.

In the example shown in FIG. 15A , the induced voltage Em is proportional to the current command i*, and the proportionality coefficient is a negative value. That is, as far as the current command generating unit 65 (i.e., the thrust adjusting unit 60B) is concerned, the greater the absolute value of the induced voltage Em, the greater the absolute value of the current command i*. In this way, the greater the induced voltage Em (the greater the speed of the vibration of the outer tank 37), the greater the absolute value of the current command i*, and the vibration of the outer tank 37 can be appropriately suppressed.

FIG. 15B is an explanatory diagram showing another example of the function used when calculating the current command i* based on the induced voltage Em.

15B , the current command i* (absolute value) for canceling the induced voltage Em may be set to a fixed value. Even in this case, the vibration of the outer tank 37 can be appropriately suppressed by the vibration control device 100B.

FIG. 15C is an explanatory diagram showing another example of the function used when calculating the current command i* based on the induced voltage Em.

In the example shown in FIG. 15C , the region where the induced voltage Em is not near zero is the same as FIG. 15B , but in the region where the induced voltage Em is near zero, the current command i* is set to zero by the current command generating unit 65 (ie, by the thrust adjusting unit 60B).

In the example of FIG. 15B described above, the positive and negative current command i* alternate in the region where the induced voltage Em is near zero, so in some cases, the operation of the linear actuator 10 is likely to become unstable. Therefore, as shown in FIG. 15C , by providing a dead zone where the current command i* is zero, the thrust of the linear actuator 10 can be stably controlled.

In the example of FIG. 15A described above, since there is no upper limit on the current command i*, in some cases, the current command i* exceeds the maximum current value of the linear actuator 10 or the inverter 40. Therefore, as shown in FIG. 15D , by setting an upper limit on the magnitude of the current command i*, the current command i* that is less than the maximum current value of the linear actuator 10 or the inverter 40 can be calculated.

(Effect)

According to the third embodiment, the induced voltage Em (a value corresponding to the speed of the outer tank 37) is estimated based on the current i and the voltage command V*, and the linear actuator 10 is controlled based on the induced voltage Em, etc. That is, by generating the thrust of the linear actuator 10 so as to cancel the speed of the outer tank 37 at each moment, the vibration of the outer tank 37 can be effectively suppressed.

(Fourth Embodiment)

The fourth embodiment differs from the third embodiment in the method of adjusting the thrust of the linear actuator 10, and the other aspects (such as the structure of the linear actuator 10 and the washing machine W) are the same as the third embodiment. Therefore, the parts different from the third embodiment will be described, and the description of the overlapping parts will be omitted.

FIG. 16 is a configuration diagram of a vibration control device 100C according to a fourth embodiment.

As shown in FIG. 16 , the vibration control device 100C includes the linear actuator 10 , the inverter 40 , the current detector 50 , a thrust adjustment unit 60C, and a speed information estimation unit 70C.

The speed information estimating unit 70C estimates the induced voltage Em based on the voltage command V* and the current i by the same method as the speed information estimating unit 70B (see FIG. 13 ) described in the third embodiment.

The thrust adjustment unit 60C has a function of calculating a voltage command V* based on the current i, the induced voltage Em, and the vibration frequency f of the outer tank 37 (object G).

FIG. 17 is a control block diagram including the thrust adjustment unit 60C included in the vibration control device 100C.

As shown in Fig. 17, the thrust adjustment unit 60C includes a subtractor 63, an ACR 64, a table 66, and a current command generation unit 67. The subtractor 63 and the ACR 64 are the same as those in the third embodiment (see Fig. 14), and thus their description is omitted.

The table 66 stores in advance data for generating the current command i* based on the induced voltage Em and the vibration frequency f of the outer groove 37. Specifically, similarly to the second embodiment, the viscosity coefficient C of the linear actuator 10 is adjusted based on the vibration frequency f of the outer groove 37. That is, as far as the current command generating unit 67 (i.e., the thrust adjusting unit 60C) is concerned, the higher the vibration frequency f of the outer groove 37, the larger the current command i* is made.

In addition, similarly to the third embodiment, the current command generation unit 67 calculates the current command i* so as to cancel the induced voltage Em. In this way, in the fourth embodiment, control is performed that produces the advantages of the second embodiment and the advantages of the third embodiment. In addition, the voltage command V* is calculated in the ACR 64 so that the current i approaches the current command i* generated by the current command generation unit 67.

(Effect)

According to the fourth embodiment, the induced voltage Em (equivalent to the value of the speed of the outer tub 37) at each moment is estimated by the speed information estimating unit 70C, and the thrust of the linear actuator 10 is adjusted by the thrust adjusting unit 60C in such a manner as to cancel out the induced voltage Em. Furthermore, the higher the vibration frequency f of the outer tub 37, the larger the current command i* is set to, so that the vibration of the outer tub 37 can be effectively suppressed. Thus, a washing machine W with high vibration damping performance at low cost can be provided.

(Variation Example)

The vibration control device 100 of the present invention is described above by using the embodiments, but the present invention is not limited to these descriptions, and various changes can be made. For example, in each embodiment, the structure of driving the left and right linear actuators 10L and 10R by a converter 40 (see FIG. 7 ) is described, but it is not limited to this.

FIG. 18 is a configuration diagram of a vibration control device 100D according to a modified example.

As shown in FIG. 18 , an inverter 40L for driving the left linear actuator 10L and an inverter 40R for driving the right linear actuator 10R may be provided separately.

The inverter 40L includes four switching elements S11 to S14 connected in a bridge. The connection point of the switching elements S11 and S12 constituting the first leg and the connection point of the switching elements S13 and S14 constituting the second leg are connected to the linear actuator 10L, respectively. The inverter 40R that drives the right linear actuator 10R also has the same structure. In this way, by providing two inverters 40L and 40R, the left and right linear actuators 10L and 10R can be independently controlled.

(Fifth Embodiment)

The first embodiment has a function of calculating the voltage command V* of the converter 40 by multiplying the current i detected by the current detector 50 by a predetermined current proportional gain Kp. (See FIG. 8 )

However, there is a problem that if the magnitude of the current proportional gain Kp is changed, the response characteristics of the controller will change. For example, if the magnitude of the current proportional gain Kp is increased, the response characteristics will deteriorate.

The difference between the fifth embodiment and the first embodiment is that the sum of the value Vp* obtained by multiplying the current i detected by the current detector 50 by the specified current proportional gain Kp and the value Vd* obtained by multiplying the differential value of the current i detected by the current detector 50 by the current differential gain Kd is used as the voltage command V* of the converter 40 (refer to Figure 8).

The rest (the structure of the linear actuator 10 and the washing machine W) is the same as that of the first embodiment. Therefore, only the parts different from the first embodiment will be described, and the description of the overlapping parts will be omitted.

In FIG. 8 , a transfer function G1 (s) that takes the induced voltage Em as input and takes the current i detected by the current detector 50 as output is expressed by equation (6).

(Formula 6)

(Formula 7)

Here, Tp shown in equation (7) is a time constant.

According to equation (7), for example, by increasing Kp, the magnitude of G1(s) shown in equation (6) can be increased. However, as Kp increases, the time constant Tp also increases. Therefore, it can be seen that the response performance deteriorates and the phase lag increases.

FIG. 19A is a control block diagram of the entire system including the thrust adjustment unit 60D and the like.

19A , thrust adjustment unit 60D includes a calculation unit 61 and a calculation unit 61A (phase compensator). Calculation unit 61 has a function of calculating voltage command Vp* for inverter 40 by multiplying current i detected by current detector 50 by a predetermined current proportional gain Kp.

Calculation unit 61A has a function of calculating voltage command Vd* for inverter 40 by differentiating current i detected by current detector 50 and multiplying the result by current differential gain Kd. Here, s is a differential sign.

The thrust adjustment unit 60D calculates a value obtained by adding the voltage command Vp* generated by the calculation unit 61 and the voltage command Vd* generated by the calculation unit 61A as the voltage command V* of the inverter 40 .

For example, when the current i of the linear actuator 10 changes in a sinusoidal wave, the operator 61 calculates a sinusoidal voltage command having substantially the same phase as the current. In addition, the operator 61A differentiates the current i, and thus calculates a cosine voltage command having a phase leading by 90 degrees with respect to the current i. By adding the voltage command Vp* generated by the operator 61 and the voltage command Vd* generated by the operator 61A and having a phase leading by 90 degrees with respect to the voltage command Vp*, the phase of the voltage command V* with respect to the current i can be advanced.

In FIG19A , the transfer function G2(s) that takes the induced voltage Em of the linear actuator 10 as input and the current i detected by the current detector 50 as output is expressed as equation (8). Here, Tdp represents a time constant, which is expressed as equation (9). According to equation (9), for example, by increasing Kp, the magnitude of G2(s) shown in equation (8) can be increased.

Furthermore, by adjusting the current differential gain Kd, the time constant Tdp can be set independently of the set value of the proportional gain Kp, and the problem of phase lag due to deterioration of response performance, which is a problem in the first embodiment, can be improved.

In addition, the proportional gain Kp is set so as to be in a range smaller than the resistance R. In addition, the differential gain Kd is set so as to be in a range smaller than the inductance L.

(Formula 8)

(Formula 9)

(Effect)

According to the fifth embodiment, the time constant Tdp can be made variable for the differential gain Kd of the current passing through, so that the vibration of the outer tank 37 can be suppressed more effectively than in the first embodiment.

FIG. 19B shows the result of thrust generated from the linear actuator 10 when a fixed excitation force is applied in the first embodiment.

In the experiment of FIG. 19B , a force of 50 N was applied to the linear actuator 10 at 5 Hz. (The same is true for FIG. 19C )

As shown in FIG. 19B , the exciting force and the thrust force are not in anti-phase and cannot fully cancel out the exciting force.

Fig. 19C shows the result of thrust generated from the linear actuator 10 when a fixed excitation force is applied in the fifth embodiment. In the experiment shown in Fig. 19C, the phase difference between the excitation force and the thrust is close to 180 degrees, and the thrust has the effect of canceling the excitation force.

For example, the current differential gain Kd may be variably controlled in accordance with the rotation speed or vibration frequency of the object. This makes it possible to make the size of the transfer function G2(s) variable and adjust the vibration damping performance.

For example, the current differential gain Kd may be set so that the time constant Tdp is fixed. Thus, even when the proportional gain Kp is made variable, the time constant can be fixed, and the vibration damping property can be fixed.

In addition, the weight of the object (the magnitude of the load) may be measured, and based on the measurement result, the thrust of the linear actuator 10 may be adjusted. For example, the greater the weight of the object, the greater the viscosity coefficient C of the linear actuator 10. In this way, the vibration of the object can be more effectively controlled.

(Sixth Embodiment)

The sixth embodiment differs from the third embodiment in that a thrust adjustment unit 60D (see FIG. 20 ) adjusts the thrust of the linear actuator 10 based on the induced voltage Em and the current i flowing in the linear actuator 10 to reduce the transmission force generated in the base 31 (see FIG. 5 ).

The rest (the structure of the linear actuator 10 and the washing machine W, etc.) is the same as that of the third embodiment. Therefore, the parts different from the third embodiment will be described, and the description of the overlapping parts will be omitted.

FIG. 20 is a configuration diagram of a vibration control device 100D according to the sixth embodiment.

As shown in FIG. 20 , the vibration control device 100D includes the linear actuator 10 , the inverter 40 , the current detector 50 , a thrust adjustment unit 60D, and a speed information estimation unit 70B.

FIG. 21 is a control block diagram including the thrust adjustment unit 60D and the speed information estimation unit 70B included in the vibration control device 100D.

The thrust adjustment unit 60D generates a predetermined voltage command V* based on the current i detected by the current detector 50 and the induced voltage Em calculated by the speed information estimation unit 70B.

As shown in Fig. 21, the thrust adjustment unit 60D includes a subtractor 63, an ACR 64 (Automatic current regulator), and a current command generation unit 65C. The ACR 64 is the same as that in the third embodiment (see Fig. 14), and thus its description is omitted.

The subtractor 63 has a function of subtracting the current i which is the detection result of the current detector 50 from the current command i** which is the calculation result of the current command generating unit 65C.

The transmission force _FB (N) generated on the base 31 by the control device 100 as an electromagnetic suspension is expressed by the following formula (10). In addition, K (N/m) shown in formula (10) is the elastic modulus of the spring 20, _FL (N) is the thrust of the linear actuator 10, and Cm (Ns/m) is the viscosity coefficient generated by the friction force of either the control device 100 or the external phase 37.

(Formula 10)

As can be seen from equation (10), even when the linear actuator 10 is not energized, i.e., the thrust _FL (N) is set to 0, the transmission force (N) is generated by the viscosity coefficient Cm (Ns/m) generated by the friction force. In particular, when the frequency of vibration increases, i.e., when the rotation time of the washing tub 35 is long during dehydration, there is a problem of increased transmission _FB (N) and increased noise.

Therefore, in the present embodiment, the thrust _FL (N) of the linear actuator 10 is controlled so as to cancel the transmission force (N) generated by the viscosity coefficient Cm (Ns/m). Specifically, the current command generating unit 65C has a function of calculating the current command i** so as to amplify the induced voltage Em based on the value of the induced voltage Em input from the speed information estimating unit 70B (see FIG. 21). That is, the linear actuator 10 is energized to amplify the vibration of the mover 12.

By amplifying the vibration amplitude of the mover 12 to cancel the transmission force (N) generated by Cm (Ns/m), the transmission force (N) generated in the base 31 can be reduced compared to the case where no current is supplied to the linear actuator 10. In addition, with respect to the current command i** of the converter 40, it is desirable that the thrust _FL (N) of the linear actuator 10 does not exceed the transmission force (N) generated by friction or the like.

FIG. 22A is an explanatory diagram showing an example of a function used when generating a current command i** based on an induced voltage Em.

In the example shown in FIG. 22A , the induced voltage Em is proportional to the current command i**, and the proportionality coefficient is a positive value. That is, as far as the current command generating unit 65C (i.e., the thrust adjusting unit 60C) is concerned, the greater the absolute value of the induced voltage Em is, the greater the absolute value of the current command i* is. In this way, the greater the induced voltage Em is (the greater the speed of the vibration of the outer tank 37 is), the greater the absolute value of the current command i** is, thereby appropriately amplifying the vibration of the outer tank 37.

FIG. 22B is an explanatory diagram showing another example of the function used when calculating the current command i** based on the induced voltage Em.

22B , the current command i** (absolute value) for amplifying the induced voltage Em may be set to a fixed value. Even in this case, the vibration of the outer tank 37 can be appropriately amplified by the vibration control device 100C.

FIG. 22 is an explanatory diagram showing another example of the function used when calculating the current command i** based on the induced voltage Em.

In the example shown in FIG. 22C , the region where the induced voltage Em is not near zero is the same as FIG. 22B , but in the region where the induced voltage Em is near zero, the current command i** is set to zero by the current command generating unit 65C (that is, by the thrust adjusting unit 60C).

In the example of FIG. 22A described above, since there is no upper limit on the current command i**, in some cases, the maximum current value of the linear actuator 10 or the inverter 40 may be exceeded. Therefore, as shown in FIG. 22D , by setting an upper limit on the magnitude of the current command i**, the current command i** below the maximum current value of the linear actuator 10 or the inverter 40 can be calculated, and demagnetization of the linear actuator 10 and damage to the inverter 40 can be prevented.

23A shows the results of the vibration speed in the vertical direction of the outer tank and the current supplied to the linear actuator 10 when the washing tub 35 is rotated at 900 (min ^-1 ) with a weight of 600 g fixed at a predetermined offset position in the washing tub 35 in the third embodiment.

23B shows the results of the vibration speed in the vertical direction of the outer tank and the current supplied to the linear actuator 10 when the washing tub 35 was rotated at 900 (min ^-1 ) with a weight of 600 g fixed at a predetermined offset position in the washing tub 35 in the sixth embodiment.

In the sixth embodiment, the speed of the wash 35 and the current i of the linear actuator 10 are generally in phase.

(Effect)

According to the sixth embodiment, the induced voltage Em (a value equivalent to the velocity of the outer groove 37) is estimated based on the current i and the voltage command V*, and the linear actuator 10 is controlled based on the induced voltage Em, etc. That is, by generating the thrust of the linear actuator 10 in a manner that amplifies the velocity of the outer groove 37 at each moment, that is, by generating the thrust of the linear actuator 10 in a manner that is the same phase as the induced voltage Em, the transmission force (N) generated by the friction force, etc. can be offset, and the transmission force generated in the base 31 can be effectively suppressed.

(Seventh Embodiment)

The seventh embodiment differs from the sixth embodiment in the method of adjusting the thrust of the linear actuator 10, but other aspects (such as the structure of the linear actuator 10 and the washing machine W) are the same as the sixth embodiment. Therefore, the parts different from the sixth embodiment will be described, and the description of the overlapping parts will be omitted.

FIG. 24 is a configuration diagram of a vibration control device 100E according to the seventh embodiment.

As shown in FIG. 24 , the vibration control device 100E includes the linear actuator 10 , the inverter 40 , the current detector 50 , a thrust adjustment unit 60E, and a speed information estimation unit 70C.

The speed information estimating unit 70C estimates the induced voltage Em based on the voltage command V* and the current i using the same method as the speed information estimating unit 70B (see FIG. 13 ) described in the third embodiment.

The thrust adjustment unit 60E has a function of calculating a voltage command V* based on the current i, the induced voltage Em, and the vibration frequency f of the outer tank 37 (object G).

FIG. 25 is a control block diagram including the thrust adjustment unit 60E included in the vibration control device 100E.

As shown in Fig. 25, the thrust adjustment unit 60E includes a subtractor 63, an ACR 64, a table 66, and a current command generation unit 67E. The subtractor 63 and the ACR 64 are the same as those in the third embodiment (see Fig. 14), and thus their description is omitted.

The table 66E stores in advance data for generating the current command i* based on the induced voltage Em and the vibration frequency f of the outer tank 37. Specifically, the viscosity coefficient C of the linear actuator 10 is adjusted based on the vibration frequency f of the outer tank 37. That is, the current command generating unit 67E (that is, the thrust adjusting unit 60E) increases the current command i* as the vibration frequency f of the outer tank 37 increases.

In addition, the current command generating unit 67 calculates the current command i** in a manner that amplifies the induced voltage Em, similarly to the sixth embodiment. In this way, in the seventh embodiment, a control that produces the advantages of the sixth embodiment is performed. Furthermore, the voltage command V* is calculated in the ACR 64 in a manner that makes the current i close to the current command i** generated by the current command generating unit 67E.

(Effect)

According to the seventh embodiment, the induced voltage Em (equivalent to the value of the speed of the outer tub 37) at each moment is estimated by the speed information estimating unit 70C, and the thrust of the linear actuator 10 is adjusted by the thrust adjusting unit 60E in such a manner as to amplify the induced voltage Em. Furthermore, the higher the vibration frequency f of the outer tub 37, the larger the current command i* is set to, and thus the transmission force generated in the base 31 can be effectively suppressed. Thus, a washing machine W with high vibration damping performance at low cost can be provided.

(Eighth Embodiment)

In the eighth embodiment, a method of avoiding a dead zone of current caused by a dead time in the inverter 40 used in the first to seventh embodiments will be described.

In the structure diagram of the converter 40 shown in FIG7 , for example, when the switch element S1 and the switch element S2 are turned on at the same time, there is a possibility that the power supply is short-circuited and the switch element is damaged. Therefore, when the switch element included in each leg is turned on and off, that is, in order to prevent the two switch elements included in each leg from being turned on at the same time, a dead time period Td is set after one element is turned on and before the other element is turned on (see FIG26A ).

During the dead time period, the current flows through the freewheeling diode (refer to FIGS. 7 and 40 ), and therefore, the voltage of each output foot is determined by the polarity of the current flowing when the switching element is turned on and off.

Fig. 26A shows the timing of turning on and off the switching elements S1 to S4 when the voltage command Vk3* and the voltage command Vk4* are given to the left and right coils of the linear motor 10L. In addition, Tri in Fig. 26A is a triangular wave carrier. For example, when the voltage command Vk3* is larger than the triangular wave carrier Tri, the on-off control is performed so that the switching element S1 is turned on and the switching element S2 is turned off.

The portion 260A surrounded by the dotted line in FIG. 26A shows the voltage Vk3 supplied to the linear motor 10L from the first pin, the voltage Vk4 supplied from the second pin, the line voltage Vk34 (obtained by subtracting the voltage Vk4 from the voltage Vk3), and the change of the current Ik3 supplied to the linear motor 10L when the current Ik3 supplied to the linear motor 10L is positive. The portion 260B surrounded by the dotted line in FIG. 26 shows the case where the current Ik3 supplied to the linear motor 10L is negative, and the meaning of each symbol is the same as that of the portion 206A. In addition, in the present embodiment, the case where the current Ik3 supplied to the linear motor 10L from the first pin is assumed to be positive.

26A , for example, when current Ik3 is positive, output voltage Vk3 is smaller than voltage command Vk3*, and output voltage Vk4 is larger than voltage command Vk4*. Therefore, an error occurs between voltage command Vk3* and voltage command Vk4*, deteriorating control performance.

FIG. 26B shows a case where the voltage command Vk3* and the voltage command Vk4* in FIG. 26A are made close to each other as an example in which the output voltage error caused by the dead time is significant. This corresponds to a case in which the voltage applied to the linear motor 10L is small, that is, a case in which the current Ik3 is to be reduced. The symbols in the 260C part are the same as those in the 260A part, so the description is omitted. In addition, the 260C part shows a case in which the current Ik3 is positive.

In the 260C part, due to the influence of the dead time, the line voltage Vk34 becomes smaller, that is, the power-on time becomes shorter. In the switching elements S1 to S4, a voltage drop is usually generated by the on-resistance, etc. Therefore, in the switching elements, etc., a voltage drop occurs, and when the output voltage decreases by an amount corresponding to the voltage drop, etc., sometimes the current Ik3 cannot be properly controlled, that is, there is a current dead zone.

FIG27 illustrates a method for avoiding the dead zone of the current caused by the dead time and the like by adding modulation to the voltage command value. The voltage command value Vk3** is a voltage command value modulated in the following manner, that is, for each half of a carrier cycle TS(s), the auxiliary voltage dV is added during the first half TS1, and the auxiliary voltage dV is subtracted during the second half TS2. That is, the voltage command value Vk3** is expressed by equation (11) during TS1 and by equation (12) during TS2.

(Formula 11)

Vk3 ^** = Vk3 ^* + dV (at TS1)

(Formula 12)

Vk3 ^** ＝Vk3 ^* -dV(at TS2)

In addition, in FIG. 27A , only the voltage command Vk3* is modulated, but other phases may be modulated. In addition, the auxiliary voltage dV may be subtracted during TS1 and added during TS2. In addition, in order to prevent the average voltage of the voltage command Vk3** during TS from changing, it is desirable that the magnitude of the auxiliary voltage dV applied during TS1 and TS2 be the same.

If on/off commands are issued to the switch elements S1 and S2 based on the voltage command value Vk3**, the output voltage Vk3 maintains the average voltage during TS, and only the on/off timing of the output voltage Vk3 is delayed and output (see section 270A Vk3 in FIG. 27A ). That is, the average value of the output voltage during TS1 and the average value of the output voltage during TS2 can be made variable.

FIG27B illustrates a case where the voltage command Vk3* and the voltage command Vk4* are 0 as a modified example of the present embodiment. In addition, the symbols are the same as those in FIG26A, so the description is omitted. When the voltage command Vk3* and the voltage command Vk4* are 0 and only Vk3* is modulated, a voltage of a pulse shape of a positive and negative object can be observed in the line voltage Vk34.

(Effect)

According to the eighth embodiment, while maintaining the average of the line voltage Vk34 applied to the left and right coils of the linear motor 10L, the energization time of at least one of the TS1 period or the TS2 period of the output voltage Vk34 can be increased. Therefore, the dead zone of the current generated by the output voltage Vk34 due to the dead time, etc., as described in FIG. 26B, etc., can be avoided.

In addition, in the present embodiment, the first and second legs of the linear motor 10L, i.e., the switch elements S1 to S4, are used in the description, but the second and third legs of the linear motor 10R, i.e., the switch elements S3 to S6, can also obtain the same effect. In addition, the same effect can also be obtained in the structure of the vibration control device of the modified example of the present invention shown in FIG. 18.

In each embodiment, the spring 20 is provided between the stator 11 (see FIG. 3 ) and the fixing jig J, but the present invention is not limited thereto. For example, a mechanism using rubber or hydraulic pressure may be applied instead of the spring 20 .

In addition, in each embodiment, the structure in which the mover 12 is connected to the outer groove 37 as the object is described, but it is not limited to this. That is, one of the stator 11 and the mover 12 can also be connected to the object, and the relative position of the stator 11 and the mover 12 can be changed by magnetic attraction/repulsion.

In addition, in each embodiment, the vibration control device 100 and the like are used to control the vibration of the washing machine W, but the present invention is not limited thereto. For example, in addition to home appliances such as air conditioners and refrigerators, each embodiment can also be applied to railway vehicles, automobiles, and the like.

Furthermore, in each embodiment, a configuration in which the linear actuator 10 is driven by single-phase AC power has been described. However, for example, the linear actuator 10 may be driven by three-phase AC power.

In addition, the embodiments are described in detail to explain the present invention more easily, and are not limited to having all the structures described. In addition, other structures can be added, deleted, or replaced with a part of the structure of the embodiment.

In addition, the above-mentioned mechanisms and structures are shown for the purpose of explanation, and not all mechanisms and structures are necessarily shown on the product.

Claims (5)

1. A vibration damping device is provided with:

a linear actuator connected to the vibration reduction target;

a transducer for driving the linear actuator;

a current detector that detects a current flowing to the linear actuator; and

A thrust adjustment unit for adjusting the thrust of the linear actuator by driving the inverter based on the current detected by the current detector,

It is characterized in that the method comprises the steps of,

The vibration damping device further includes a speed information estimating unit that estimates a value corresponding to a speed of the vibration damping object based on the current detected by the current detector and the voltage command of the inverter calculated by the thrust adjusting unit,

The thrust force adjusting unit calculates a current command of the inverter so as to cancel a value corresponding to the speed of the vibration reduction target object, and calculates the voltage command so as to bring the current close to the current command.

2. A vibration damping device according to claim 1, characterized in that,

The thrust force adjusting unit increases the absolute value of the current command as the absolute value of the speed corresponding to the vibration reduction object increases.

3. A vibration damping device according to claim 1, characterized in that,

In a region around zero corresponding to the speed of the vibration reduction object, the thrust force adjustment unit sets the current command to zero.

4. A vibration damping device according to claim 1, characterized in that,

The thrust force adjusting unit increases the current command as the vibration frequency of the vibration reduction target is higher.

5. A vibration damping device according to claim 1, characterized in that,

The linear actuator has a stator as an armature and a mover having a permanent magnet,

The permanent magnet is a samarium-iron-nitrogen permanent magnet.