WO2011115098A1 - Control device and control method - Google Patents

Abstract

The disclosed control device is provided with: a magnetic pole position calculation unit which receives a signal corresponding to the direction of the lines of magnetic flux from a magnetism sensor which is arranged facing a magnet used for linear-motor drive, and calculates a first estimated magnetic pole position from the received signal; and a control unit which selects one of either the first estimated magnetic pole position, or a second estimated magnetic pole position, the magnetic pole position of which differs from the first estimated magnetic pole position by 180°, and determines the selected estimated magnetic pole position to be an initial magnetic pole position.

Description

Control device and control method

The present invention relates to a motor control device and a control method.
This application claims priority on March 17, 2010 based on Japanese Patent Application No. 2010-060987 filed in Japan, the contents of which are incorporated herein by reference.

As a method of estimating the initial magnetic pole position, which is the magnetic pole position (or electrical angle) at the start of the synchronous motor, a current corresponding to the n-divided phase is applied to the synchronous motor, and the moving direction (+ , 0, −), and a current corresponding to the phase obtained by dividing the electrical angle region in which the moving direction changes from + to 0 and from 0 to − is divided into two. The determination of the moving direction at this time is repeated several times, and the phase where the generated electromagnetic force becomes zero is determined as the initial magnetic pole position at the intermediate point of the electrical angle region where the moving direction becomes 0, and synchronization is performed based on the determined phase. There is a technique for starting an electric motor (Patent Document 1).

JP 2006-296027 A

However, when the initial magnetic pole position is determined by the above technique, it is necessary to energize a plurality of times, and there is a problem that the time required to detect the initial magnetic pole position becomes long.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a control device and a control method capable of shortening the time required to detect the initial magnetic pole position when starting the synchronous motor. is there.

In order to solve the above problem, the present invention includes a magnet unit including a plurality of magnets in which N-pole and S-pole magnetic poles are alternately arranged in the axial direction, and an armature including a plurality of coils. One of the armature or the magnet unit in the axial direction is caused by a magnetic field generated by flowing current through a plurality of coils provided in the armature and a magnetic field generated by a plurality of magnets provided in the magnet unit. A linear motor control device that performs linear motion, wherein magnetic flux lines of a magnetic field generated by the plurality of magnets from a magnetic sensor provided in the armature are opposed to the plurality of magnets provided in the magnet unit. A magnetic pole position calculation unit that receives a signal according to a direction and calculates a first estimated magnetic pole position according to the received signal; a second estimated magnetic pole position that is 180 ° different from the first estimated magnetic pole position; First estimated magnetism Selects one of the position, a control device, characterized in that it comprises a determining controller the estimated magnetic pole position selected as the initial magnetic pole position.

In addition, the present invention includes a magnet unit including a plurality of magnets in which N-pole and S-pole magnetic poles are alternately arranged in the axial direction, and an armature including a plurality of coils, and is provided in the armature. A linear motor in which one of the armature or the magnet unit linearly moves in the axial direction by a magnetic field generated by flowing current through a plurality of coils and a magnetic field generated by a plurality of magnets provided in the magnet unit The control method of the control device according to claim 1, wherein the magnetic device is arranged in a direction opposite to a plurality of magnets provided in the magnet unit according to a direction of magnetic flux lines of a magnetic field generated by the plurality of magnets from a magnetic sensor provided in the armature. A magnetic pole position calculation step of calculating a first estimated magnetic pole position according to the received signal, a second estimated magnetic pole position that is 180 ° different from the first estimated magnetic pole position, and the first estimated magnetic pole position. You select one of the pole position is a control method characterized in that it comprises a determination step of determining an estimated magnetic pole position selected as the initial magnetic pole position.

According to the present invention, the time required for detecting the initial magnetic pole position can be shortened by reducing the number of times the motor is energized when starting the synchronous motor.

It is the schematic which shows the linear motor apparatus 1 in 1st Embodiment. 2 is a perspective view (including a cross section of a table 53) of the linear motor 20 in the same embodiment. FIG. It is a front view of the linear motor 20 in the embodiment. It is a figure which shows the cross section along the moving direction of the armature 60 in the embodiment. 2 is a schematic block diagram illustrating configurations of a control device 10 and a mover 25 in the same embodiment. FIG. 4 is a schematic diagram showing a relative position of an MR sensor 27 and coils 28u, 28v, 28w provided in the mover 25 and a magnet 24 arranged in the stator 21 in the same embodiment. FIG. It is a graph which shows an example of the correspondence of the signal output from MR sensor 27 in the embodiment, and the voltage Vu, Vv, Vw applied to coils 28u, 28v, 28w, and the magnetic pole position. It is a flowchart which shows the process which the control apparatus 10 in the embodiment detects an initial pole position. It is the 1st schematic diagram showing composition of linear motor 30 in a 2nd embodiment. It is a 2nd schematic diagram which shows the structure of the linear motor 30 in the embodiment. It is a schematic block diagram which shows the structure of the control apparatus 40 which controls the linear motor 30 in the embodiment. It is a flowchart which shows the process in which the control apparatus 40 in the embodiment detects an initial magnetic pole position.

Hereinafter, a control device and a control method according to an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic diagram showing a linear motor device 1 in the present embodiment. The linear motor device 1 includes a control device 10 and a linear motor 20. The control device 10 is a device that controls to drive the linear motor 20. The linear motor 20 includes a long stator 21, a mover 25 that moves on the stator 21, and a pair of guide devices 22 and 22 for assembling the stator 21 and the mover 25.

The guide device 22 includes, for example, a track rail 23 and a slide block 26 assembled via a ball. The track rail 23 of the guide device 22 is fixed to the base 54 of the stator 21, and the slide block 26 of the guide device 22 is fixed to the mover 25, so that the mover 25 moves on the stator 21 along the track rail 23. You can be guided freely.
The stator 21 includes a plurality of driving magnets 24 arranged between the pair of track rails 23 and 23. The plurality of drive magnets 24 are arranged so that the N-pole and S-pole magnetic poles alternate in the moving direction, which is the direction in which the mover 25 moves. The drive magnets 24 have the same length in the movement direction. Accordingly, the movable element 25 can obtain a constant thrust at any position on the stator 21.

The mover 25 includes an armature 60 having a plurality of coils, a table on which a moving object is placed, and an MR (Magnetoresistive Elements) sensor 27 that is a magnetic sensor. The MR sensor 27 includes a magnetoresistive element and outputs a signal corresponding to the direction of the magnetic flux line of the magnetic field generated by the driving magnet 24 disposed on the stator 21 to the control device 10.
Based on the signal output from the MR sensor 27, the control device 10 supplies current to the plurality of coils included in the armature 60. Thereby, the mover 25 is moved to the track rail 23 by the action of the magnetic field generated in the plurality of coils of the armature 60 and the magnetic field generated by the driving magnet 24 arranged on the stator 21. Move along.

A detailed configuration of the linear motor 20 in the present embodiment will be described. FIG. 2 is a perspective view of the linear motor 20 (including a cross section of the table 53). FIG. 3 is a front view of the linear motor 20.
In the linear motor 20, a plurality of plate-like drive magnets 24 in which the stator 21 is arranged with the surface magnetized in either the N pole or the S pole facing the mover 25 as described above. It has. The mover includes an armature having a plurality of coils, and moves relative to the stator 21 along the track rail 23. That is, the linear motor 20 in the present embodiment is a flat type linear motor.
The armature 60 provided in the mover 25 is opposed to the driving magnet 24 via the gap g.

The plurality of driving magnets 24 described above are arranged in a row in the moving direction on the elongated base 54 of the stator 21. The base 54 includes a bottom wall portion 54a and a pair of side wall portions 54b provided on both sides in the width direction of the bottom wall portion 54a. The plurality of driving magnets 24 described above are attached to the bottom wall portion 54a.
Each of the plurality of drive magnets 24 is formed with N and S poles on both end faces in a direction perpendicular to the moving direction and in a direction facing the armature 60 (vertical direction in FIG. 3). The plurality of drive magnets 24 are arranged with their magnetic poles different from the adjacent drive magnets 24 facing the armature 60 facing each other. Thus, the MR sensor 27 attached to the mover 25 alternately faces the N pole and the S pole of the plurality of drive magnets 24 when the mover 25 moves.

The track rail 23 of the guide device 22 is attached to the upper surface of the side wall 54b of the base 54. The track rail 23 and the slide block 26 are assembled via a plurality of balls (not shown). The slide block 26 is provided with a track-shaped ball circulation path for circulating a plurality of balls. When the slide block 26 slides on the track rail 23, a plurality of balls circulate in the ball circulation path. Thereby, the slide block 26 can smoothly slide on the track rail 23 with a small sliding resistance.

A table 53 of the mover 25 is attached to the upper surface of the slide block 26 of the guide device 22. The table 53 is a table on which a moving object made of a nonmagnetic material is placed, and is made of, for example, aluminum.
An armature 60 is suspended from the lower surface of the table 53. As shown in the front view of FIG. 4, a gap g is provided between the driving magnet 24 and the armature 60. The guide device 22 keeps the clearance g between the armature 60 and the driving magnet 24 constant even when the mover 25 moves relative to the stator 21.
As shown in FIG. 3, the MR sensor 27 is attached to the armature 60. When the armature 60 moves, the MR sensor 27 moves with the armature 60 and detects a change in the direction of the magnetic flux lines generated by the driving magnets 24 arranged on the stator 21.

FIG. 4 is a view showing a cross-sectional view along the moving direction of the mover 25 in the present embodiment. A heat insulating material 63 is attached between the lower surface of the table 53 and the armature 60. The armature 60 includes a core 64 made of a magnetic material such as silicon steel, and the coils 28u, 28v, 28w that are the plurality of coils described above. The coils 28u, 28v, and 28w are wound around the salient poles 64u, 64v, and 64w and sealed with resin. Three-phase alternating current having a predetermined phase difference is supplied from the control device 10 to the coils 28u, 28v, 28w.
A pair of auxiliary cores 67 are attached to the lower surface of the table 53 with the armature 60 interposed therebetween. The auxiliary core 67 is provided to reduce cogging generated in the linear motor 20.

FIG. 5 is a schematic block diagram showing the configuration of the control device 10 and the mover 25 in the present embodiment. As shown in the figure, the control device 10 includes line receivers 11 a and 11 b, a magnetic pole position calculation unit 12, a control unit 13, and a drive unit 14. As described above, the mover 25 includes the MR sensor 27 and the three coils 28u, 28v, and 28w as a plurality of coils.

In the control device 10, the line receivers 11 a and 11 b receive two differential signals output from the MR sensor 27 provided in the mover 25. The line receivers 11 a and 11 b remove noise signals from the two input differential signals, and output the two differential signals from which the noise signals have been removed to the magnetic pole position calculation unit 12. The two differential signals are a sine wave signal (Ssin) and a cosine wave signal (Scos), and are signals having a phase difference of (π / 2).
The magnetic pole position calculation unit 12 calculates the estimated magnetic pole position θ based on the sine wave signal and the cosine wave signal input from the line receivers 11a and 11b. The calculation method is to calculate the estimated magnetic pole position θ by calculating arctan (or tan-1, arc tangent; arc tangent function) with respect to the division result of ((sine wave signal) / (cosine wave signal)). .
The line receivers 11a and 11b and the magnetic pole position calculation unit 12 may be provided in the mover 25.

The control unit 13 includes a magnetic pole position detection unit 131 and a mover position detection unit 132. Based on the information indicating the magnetic pole position input from the magnetic pole position calculator 12, the magnetic pole position detector 131 applies the coils 28 u, 28 v, 28 w of the mover 25 and the stator 21 before moving the mover 25. A magnetic pole position indicating a relative positional relationship with the arranged drive magnet 24 is detected.
The mover position detector 132 calculates the amount of movement of the mover 25 based on the information indicating the magnetic pole position input from the magnetic pole position calculator 12, and calculates the relative position of the mover 25. That is, the mover position detection unit 132 performs relative position detection using the drive magnet 24.
The drive unit 14 energizes the coils 28 u, 28 v, 28 w provided in the mover 25 under the control of the control unit 13.

In the mover 25, the MR sensor 27 is a vector detection type magnetic sensor, and the sine wave signal and the cosine wave signal described above according to the direction of the magnetic flux line by the driving magnet 24 provided in the stator 21. Is output. As shown in FIG. 5, the MR sensor 27 has full bridge circuits 27 a and 27 b made up of ferromagnetic thin film elements whose resistance values change depending on the direction of the magnetic flux lines that pass therethrough. The full bridge circuits 27a and 27b are formed on one substrate, for example, and output a sine wave signal and a cosine wave signal having a phase difference of (π / 2) with respect to the sine wave signal from each terminal. Are arranged as follows.

In the present embodiment, the mover position detector 132 detects the moving direction of the mover 25 based on the change in the estimated magnetic pole position θ calculated by the magnetic pole position calculator 12 using the sine wave signal and the cosine wave signal. . Further, the mover position detection unit 132 calculates the movement amount of the mover 25 from the conversion amount of the estimated magnetic pole position θ and the interval between the driving magnets 24 provided in the stator 21. That is, the mover position detection unit 132 calculates the movement direction and the movement amount of the mover 25 based on the magnetic flux generated from the driving magnet 24 provided in the stator 21, thereby determining the position of the mover 25. Is detected.

FIG. 6 shows the relative relationship between the MR sensor 27 and the coils 28u, 28v, 28w provided in the mover 25 and the driving magnets 24 (24n, 24s) provided in the stator 21. It is a schematic diagram which shows a position. As described above, the driving magnets 24 are arranged on the stator 21 at equal intervals so that the magnetic poles of the N pole and the S pole alternate in the moving direction.
In the mover 25, the coils 28u, 28v, 28w are arranged side by side in the moving direction so as to face the magnetic poles arranged on the stator 21. The MR sensor 27 is disposed at a position facing the central portion of each driving magnet 24 so that the magnetic field generated by the driving magnet 24 passes through the position where the magnetic field is strongest.

FIG. 7 shows the sine wave signal and cosine wave signal output from the MR sensor 27 in this embodiment, the voltages Vu, Vv, Vw applied to the coils 28u, 28v, 28w, and the magnetic pole position (0 °) of the armature 60. It is a graph which shows an example of a correspondence with (... 360 degrees). In the figure, the horizontal axis indicates the magnetic pole position, and the vertical axis indicates the level of the sine wave signal and cosine wave signal of the MR sensor 27, and the level of the voltage applied to the coils 28u, 28v, 28w. In the vertical axis direction, the sine wave signal, the cosine wave signal, and the voltages Vu, Vv, and Vw are normalized relative values.

As shown in the figure, the values of the sine wave signal (Ssin) and the cosine wave signal (Scos) output from the MR sensor 27 are in the direction of magnetic flux lines (magnetic pole positions) of the magnetic field generated by the opposing drive magnet 24. Will change accordingly. In addition, when the magnetic poles of the opposing driving magnet 24 change in order of N pole, S pole, and N pole, the MR sensor 27 corresponds to two cycles according to the change in the direction of the magnetic flux generated by each of the driving magnets 24. Sine wave signal (Ssin) and cosine wave signal (Scos).
That is, when the armature 60 of the mover 25 is positioned at a magnetic pole position having a phase difference of 180 °, the value of the sine wave signal output from the MR sensor 27 becomes the same value at each magnetic pole position, and the cosine. The value of the wave signal is also the same value. Further, two magnetic pole positions are estimated from the sine wave signal and cosine wave signal output from the MR sensor 27.

The magnetic pole position calculation unit 12 calculates the first estimated magnetic pole position θ (0 ° ≦ θ <180 °) from the sine wave signal (Ssin) and the cosine wave signal (Scos) output from the MR sensor 27. The magnetic pole position detector 131 uses the first estimated magnetic pole position θ calculated by the magnetic pole position calculator 12 and the second estimated magnetic pole position (θ + 180 °) obtained by adding 180 ° to the estimated magnetic pole position θ as the initial magnetic pole position. Make a candidate.
That is, the magnetic pole position calculation unit 12 calculates the first estimated magnetic pole position θ according to the direction of the magnetic flux generated by the drive magnet 24, and the magnetic pole position detection unit 131 performs the second estimation from the calculated first estimated magnetic pole position θ. The magnetic pole position (θ + 180 °) is calculated, and two estimated magnetic pole positions are made candidates for the initial magnetic pole position to be detected.

The figure also shows excitation patterns for the coils 28u, 28v, 28w according to the magnetic pole positions. The excitation pattern is a ratio of voltages Vu, Vv, Vw applied to the coils 28u, 28v, 28w corresponding to the magnetic pole positions. The drive unit 14 stores the excitation pattern shown in the figure in association with the magnetic pole position. Then, the drive unit 14 energizes the coils 28 u, 28 v, 28 w with the excitation pattern corresponding to the magnetic pole position input from the magnetic pole position detection unit 131.

Next, a process for detecting an initial magnetic pole position that is a magnetic pole position of the armature 60 that is detected when driving of the linear motor 20 in the present embodiment is started will be described.
FIG. 8 is a flowchart illustrating processing in which the control device 10 according to the present embodiment detects the initial pole position.
In the control device 10, when detection of the initial magnetic pole position is started, the magnetic pole position calculation unit 12 calculates the first estimated magnetic pole position θ from the sine wave signal and the cosine wave signal input from the MR sensor 27 (step S101). ).

The magnetic pole position detector 131 stores the first estimated magnetic pole position θ calculated by the magnetic pole position calculator 12. The magnetic pole position detector 131 controls the drive unit 14 to energize the coils 28u, 28v, and 28w with an excitation pattern corresponding to a magnetic pole position (θ + 90 °) shifted by + 90 ° from the first estimated magnetic pole position θ. (Step S102).
At this time, when the drive unit 14 energizes the coils 28u, 28v, 28w, the current passed through the coils 28u, 28v, 28w at predetermined steps from the initial current value to the maximum current value at predetermined time intervals. Increase the current value. In addition, when the current value of the current flowing through the coils 28u, 28v, 28w reaches the maximum current value, the drive unit 14 stops energization of the coils 28u, 28v, 28w. Here, the initial current value is a current value at which the mover 25 starts to move when the load applied to the mover 25 is minimum. The maximum current value is a current value at which the mover 25 starts to move when the load that can be applied to the mover 25 is the maximum in the design of the linear motor 20. Appropriate values are set for the initial current value, the maximum current value, and the constant time interval based on simulation and actual measurement.
Thereby, even when the mover 25 (armature 60) moves, the amount of movement can be reduced by gradually strengthening the magnetic field generated in the coils 28u, 28v, 28w by energization.

The magnetic pole position detection unit 131 detects that the mover 25 has moved based on changes in the sine wave signal and the cosine wave signal, or the current value of the current flowing through the coils 28u, 28v, 28w becomes the maximum current value. When it reaches, the drive unit 14 is controlled to stop energization (step S103).
The magnetic pole position detection unit 131 determines whether or not the mover 25 has moved in the positive direction in which the angle indicating the magnetic pole position increases during energization in step S102 (step S104). Note that when the angle indicating the magnetic pole position changes beyond 360 °, the magnetic pole position detector 131 determines that the magnetic pole position has increased.

When the mover 25 moves in the positive direction (step S104: YES), the magnetic pole position detector 131 determines that the magnetic pole position where the mover 25 is located is the first estimated magnetic pole position θ (step S105). The process of detecting the magnetic pole position is terminated.
On the other hand, when the mover 25 has not moved in the positive direction (step S104: NO), the magnetic pole position detector 131 determines whether or not the mover 25 has moved in the negative direction in which the angle indicating the magnetic pole position decreases. Determination is made (step S110).

When the mover 25 moves in the negative direction (step S110: YES), the magnetic pole position detector 131 determines that the magnetic pole position where the mover 25 is located is the second estimated magnetic pole position (θ + 180 °) (step S111). ), The process of detecting the initial magnetic pole position is terminated.
On the other hand, when the mover 25 does not move in the negative direction (step S110: NO), the magnetic pole position detector 131 corresponds to the magnetic pole position (θ-90 °) shifted by −90 ° from the first estimated magnetic pole position θ. Control for energizing the coils 28u, 28v, 28w with the excitation pattern is performed on the drive unit 14 (step S120). At this time, similarly to step S102, the drive unit 14 increases the current value of the current flowing through the coils 28u, 28v, 28w from the initial current value to the maximum current value at a constant time interval.

The magnetic pole position detection unit 131 detects that the mover 25 has moved based on changes in the sine wave signal and the cosine wave signal, or the current value of the current flowing through the coils 28u, 28v, 28w becomes the maximum current value. When it reaches, the drive unit 14 is controlled to stop energization (step S121).
The magnetic pole position detection unit 131 determines whether or not the mover 25 has moved in the forward direction during energization in step S120 (step S122).

When the mover 25 moves in the positive direction (step S122: YES), the magnetic pole position detector 131 determines that the magnetic pole position where the mover 25 is located is the second estimated magnetic pole position (θ + 180 °) (step S123). ), The process of detecting the initial magnetic pole position is terminated.
On the other hand, when the mover 25 has not moved in the positive direction (step S122: NO), the magnetic pole position detector 131 determines whether the mover 25 has moved in the negative direction (step S130).

When the mover 25 moves in the negative direction (step S130: YES), the magnetic pole position detector 131 determines that the magnetic pole position at which the mover 25 is located is the first estimated magnetic pole position θ (step S131). The process of detecting the magnetic pole position is terminated.
On the other hand, when the mover 25 does not move in the negative direction (step S130: NO), the magnetic pole position detection unit 131 causes the linear motor 20 to perform any operation when the mover 25 does not move due to energization in steps S102 and S120. It is determined that a defect has occurred, error processing is performed (step S140), and the processing for detecting the initial magnetic pole position is terminated. Here, the error process in step S140 is a process of outputting information indicating that a problem has occurred in the linear motor 20 to the user of the linear motor device 1.

As described above, the control device 10 according to the present embodiment uses the two excitation patterns corresponding to the magnetic pole position (θ + 90 °) and the magnetic pole position (θ−90 °) calculated from the first estimated magnetic pole position θ, The coils 28u, 28v, 28w are energized. When the coils 28u, 28v, and 28w are energized, the magnetic pole position detector 131 determines which of the first estimated magnetic pole position θ and the second estimated magnetic pole position (θ + 180 °) based on the direction in which the mover 25 has moved. It is possible to detect whether or not the mover 25 is positioned at the same time and to detect a malfunction in the linear motor 20.
As described above, the control device 10 according to the present embodiment can detect the magnetic pole position of the mover 25 by energizing the coils 28u, 28v, and 28w at most twice, thereby detecting the magnetic pole position. The time required can be shortened.

Further, when the mover 25 of the linear motor 20 is in contact with the end of the operating range on the stator 21, the control device 10 can detect either the magnetic pole position (θ + 90 °) or (magnetic pole position (θ-90). In some cases, the control unit 10 may not move the magnetic pole position (θ + 90 °) and (magnetic pole position) in the processing of step S102 and step S120. Energization is performed with two excitation patterns corresponding to (θ−90), so that the control device 10 can move the mover 25 even in the above-described case, and the magnetic pole position of the mover 25 can be moved. Can be detected correctly.

In the detection of the magnetic pole position, the linear motor 20 is started by energizing the coils 28u, 28v, and 28w with an excitation pattern corresponding to a predetermined set position and moving the mover 25 to the set position. There is a method of determining the magnetic pole position when performing. However, this method has a problem that the mover 25 moves a distance of an electrical angle of 180 ° in the largest case.
Since the control device 10 in the present embodiment has a configuration (step S103 and step S121) that stops energization when the movement of the mover 25 is detected, the distance that the mover 25 moves when detecting the initial magnetic pole position. Can be minimized.

In the linear motor 20 of the present embodiment, the mover 25 includes an armature 60, and the armature 60 includes coils 28u, 28v, and 28w. That is, the coils 28u, 28v, 28w are a part of the armature 60, and the armature 60 is a part of the mover. The stator 21 includes a plurality of driving magnets 24 that are magnet portions. The linear motor 20 is a flat type linear motor in which the armature 60 moves by energizing the coils 28u, 28v, 28w. However, the above-described process of detecting the initial magnetic pole position may be applied to a linear motor having a configuration in which the armature is a part of the stator and the magnet part is a part of the mover.

In the present embodiment, the configuration in which the coils 28u, 28v, and 28w are energized using the excitation pattern corresponding to the magnetic pole position shifted by 90 ° with respect to the first estimated magnetic pole position θ in steps S102 and S120 has been described. . However, the present invention is not limited to this, and the coils 28u, 28v, and 28w are energized using the excitation pattern corresponding to the magnetic pole position shifted by α (0 ° <α <180 °) with respect to the first estimated magnetic pole position θ. May be. When α = 90 °, the difference between the magnetic pole position and the excitation pattern is 90 ° regardless of whether the mover 25 is positioned at either the first estimated magnetic pole position θ or the second estimated magnetic pole position (θ + 180). . As a result, even when the mover 25 is located at either the first estimated magnetic pole position θ or the second estimated magnetic pole position (θ + 180), a movement amount of 90 ° can be secured as the magnetic pole position, and the movable element 25 is movable. The accuracy of determining the direction in which the child 25 has moved can be improved.

In steps S102 and S120, the coils 28u, 28v, and 28w are energized using the excitation pattern corresponding to the magnetic pole position shifted by β (180 ° <β <360 °) with respect to the first estimated magnetic pole position. May be. In this case, in the determination of the moving direction in step S104, step S110, step S122, and step S130, the “positive direction” and the “negative direction” are opposite in each step.

In the present embodiment, in steps S102 and S120, the current value of the current passed through the coils 28u, 28v, and 28w is determined at predetermined steps from the initial current value to the maximum current value at predetermined time intervals. The structure to raise was demonstrated. However, the present invention is not limited to this, and the current having the maximum current value may be energized a predetermined number of times in a pulse shape. As a result, the time required for energization can be shortened as compared with the case where the current value passed through the coils 28u, 28v, 28w is gradually increased.

[Second Embodiment]
The linear motor device according to the second embodiment is different from the linear motor device according to the first embodiment in that it includes a rod-type linear motor. In addition to the MR sensor, the linear motor in this embodiment includes a hall sensor. Hereinafter, in the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

9 and 10 are schematic views showing the configuration of the linear motor 30 in the second embodiment. 9 and 10 include cross-sectional views of the linear motor 30. FIG.
The linear motor 30 is a rod-type linear motor in which a rod that is a mover moves relatively in the longitudinal direction with respect to a long coil housing case 31 that is an armature. Inside the coil storage case 31, a plurality of coils 33 are stacked in the longitudinal direction. The plurality of coils 33 includes a U-phase coil 33u, a V-phase coil 33v, and a W-phase coil 33w as a set, and a plurality of sets of coils 33 are sequentially stacked.
Further, end cases 34 are attached to both end faces of the coil storage case 31. Bushings 35 a and 35 b that are bearings for guiding the linear motion of the rod 32 are attached to the end case 34.

The rod 32 which is a mover is made of, for example, a non-magnetic material such as stainless steel and has a hollow space like a pipe. In the hollow space of the rod 32, a plurality of cylindrical drive magnets 36 are laminated in the longitudinal direction with their same poles facing each other. That is, the plurality of drive magnets 36 are stacked such that the N pole and the N pole face each other, and the S pole and the S pole face each other. A pole shoe 37 made of a soft magnetic material such as iron is interposed between adjacent drive magnets 36. By interposing the pole shoe 37, the change in the magnetic flux density generated in the rod 32 can be brought close to a sine wave shape.

Further, the rod 32 penetrates through the plurality of coils 33 stacked inside the coil storage case 31. The rod 32 is supported so as to be movable in the longitudinal direction with respect to the coil storage case 31.
A sensor case 38 is provided so as to be in contact with one of the end cases 34 attached to both end surfaces of the coil storage case 31. That is, one end case 34 is sandwiched between the coil storage case 31 and the sensor case 38 in the direction in which the rod 32 moves.

The sensor case 38 is provided with a substrate 381. An MR sensor 27 as a magnetic sensor is attached to one main surface of the substrate 381 so as to face the rod 32. A hall sensor 382 as a magnetic pole sensor is attached to the other main surface of the substrate 381 so as to face the rod 31. Thus, since the MR sensor 27 and the Hall sensor 382 are attached to each main surface of the substrate 381, the size of the substrate 381 can be shortened in the direction in which the rod 32 moves. Note that the MR sensor 27 and the Hall sensor 382 may be attached to one main surface of the substrate 381.
In FIG. 10, the sensor case 38 is not shown for easy identification of the MR sensor 27 and the Hall sensor 382.

The MR sensor 27 outputs two signals according to the direction of the magnetic flux lines of the magnetic field generated by the drive magnet 36 in the opposing rod 31. Similar to the first embodiment, the two signals are a sine wave signal and a cosine wave signal having a phase difference of (π / 2) from the sine wave signal.
The hall sensor 382 outputs a magnetic pole signal that is a signal corresponding to the magnetic pole of the driving magnet 36 in the opposing rod 31. The magnetic pole signal is a signal indicating whether the Hall sensor 382 detects the N pole or the S pole.

FIG. 11 is a schematic block diagram showing the configuration of the control device 40 that controls the linear motor 30 in the present embodiment. FIG. 11 shows a part of the configuration of the linear motor 30. Of the configuration of the linear motor 30, a set of coils 33 u, 33 v, 33 w, a hall sensor 382, and an MR sensor 27 are shown. ing. The control device 40 of the present embodiment is different from the configuration of the control device 10 of the first embodiment in that the magnetic pole signal output from the hall sensor 382 is input.

As shown in the figure, the control device 40 includes three line receivers 11 a, 11 b, 11 c, a magnetic pole position calculation unit 12, a control unit 43, and a drive unit 44.
In the control device 40, the line receiver 11c receives the magnetic pole signal output from the hall sensor 382 provided in the linear motor 30. The magnetic pole signal output from the hall sensor 382 is a differential signal. The line receiver 11 c removes the noise signal from the input magnetic pole signal and outputs the magnetic pole signal from which the noise signal has been removed to the control unit 43. In the present embodiment, the relationship between the sine wave signal and the cosine wave signal output from the MR sensor 27 and the magnetic pole position indicated by 0 ° to 360 ° is shown in FIG. 7 as in the first embodiment. And have a relationship. That is, the S pole corresponds to the range of the magnetic pole position from 135 ° to 315 °, and the N pole corresponds to the range of the magnetic pole position from 0 ° to 135 ° and from 315 ° to 360 °. To do.

The control unit 43 includes a magnetic pole position detection unit 431 and a mover position detection unit 132. The magnetic pole position detection unit 431, based on the information indicating the magnetic pole position input from the magnetic pole position calculation unit 12, before driving the linear motor 30, a plurality of coils 33 provided in the coil storage case 31 that is a stator. And a magnetic pole position indicating a relative positional relationship with the plurality of driving magnets 36 stacked on the rod 32 which is a mover.
The drive unit 44 drives the linear motor 30 by energizing the plurality of coils 33 with a three-phase alternating current having a predetermined phase difference based on the control of the control unit 43.

FIG. 12 is a flowchart illustrating processing in which the control device 40 according to the present embodiment detects the initial magnetic pole position.
When the detection of the initial magnetic pole position is started in the control device 40, the magnetic pole position calculation unit 12 calculates the first estimated magnetic pole position θ from the sine wave signal and the cosine wave signal input from the MR sensor 27 (step S201). ).
The magnetic pole position detection unit 431 determines whether or not the magnetic pole signal input from the hall sensor 382 indicates the S pole (step S202).

When the magnetic pole signal indicates the S pole (step S202: YES), the magnetic pole position detection unit 431 has 135 ° to 315 ° out of the first estimated magnetic pole position θ and the second estimated magnetic pole position (θ + 180 °). The estimated magnetic pole positions included in the above are selected. The magnetic pole position detection unit 431 determines that the initial magnetic pole position of the linear motor 30 is the selected estimated magnetic pole position (step S203), and ends the process of detecting the initial magnetic pole position.
On the other hand, when the magnetic pole signal indicates the N pole (step S202: NO), the magnetic pole position detection unit 431 starts from 135 ° out of the first estimated magnetic pole position θ and the second estimated magnetic pole position (θ + 180 °). An estimated magnetic pole position that is not included by 315 ° is selected. The magnetic pole position detection unit 431 determines that the initial magnetic pole position of the linear motor 30 is the selected estimated magnetic pole position (step S204), and ends the process of detecting the initial magnetic pole position.

As described above, the control device 40 according to the present embodiment, based on the magnetic pole signal output from the Hall sensor 382, is one of the first estimated magnetic pole position θ and the second estimated magnetic pole position (θ + 180 °). The position is detected as the initial magnetic pole position of the linear motor 30.
Thus, the control device 40 can detect the initial magnetic pole position of the linear motor 30 without energizing the linear motor 30, and can shorten the time required for detecting the initial magnetic pole position.
Further, since the control device 40 does not energize the linear motor 30, it is possible to detect the initial magnetic pole position without driving the linear motor 30.

In the present embodiment, the case where the relationship between the sine wave signal and cosine wave signal output from the MR sensor 27 and the magnetic pole position is the relationship shown in FIG. 7 has been described. However, the S pole corresponds to a range from 135 ° to 315 °, and the N pole is not limited to a range from 0 ° to 135 ° and a range from 315 ° to 360 °. That is, in step S203 and step S204, the magnetic pole position detection unit 431 may select an estimated magnetic pole position included in the magnetic pole position range corresponding to the magnetic pole detected by the hall sensor 382.

In the first embodiment, the configuration for detecting the initial magnetic pole position in the flat type linear motor has been described. However, the configuration may be applied to a rod type linear motor. In the second embodiment, the configuration for detecting the initial magnetic pole position in the rod-type linear motor has been described. However, the configuration may be applied to a flat-type linear motor.

According to the present invention, the time required for detecting the initial magnetic pole position can be shortened by reducing the number of times the motor is energized when starting the synchronous motor.

10, 40 Control device 20, 30 Linear motor 12 Magnetic pole position calculation unit 13, 43 Control unit 14, 44 Drive unit 131, 431 Magnetic pole position detection unit

Claims (7)

1. A magnet unit including a plurality of magnets in which N-pole and S-pole magnetic poles are alternately arranged in the axial direction, and an armature including a plurality of coils, and the plurality of coils provided in the armature A control apparatus for a linear motor in which one of the armature or the magnet unit linearly moves in the axial direction by a magnetic field generated by passing a current and a magnetic field generated by a plurality of magnets provided in the magnet unit. ,
   A signal corresponding to the direction of the magnetic flux lines of the magnetic field generated by the plurality of magnets is received from the magnetic sensor provided in the armature so as to face the plurality of magnets provided in the magnet unit, and the received signal is A magnetic pole position calculation unit that calculates a first estimated magnetic pole position according to the
   A controller that selects one of the second estimated magnetic pole position, which is 180 ° different from the first estimated magnetic pole position, and the first estimated magnetic pole position, and determines the selected estimated magnetic pole position as an initial magnetic pole position; A control device comprising:
2. A drive unit for energizing the plurality of coils using an excitation pattern determined in advance according to the first estimated magnetic pole position;
   The controller is
   When the drive unit energizes the plurality of coils, based on a signal output from the magnetic sensor, one of the first estimated magnetic pole position and the second estimated magnetic pole position is selected and selected. The control apparatus according to claim 1, wherein the estimated magnetic pole position is determined as an initial magnetic pole position.
3. The controller is
   Based on a signal output from a magnetic pole sensor provided in the linear motor, one of the first estimated magnetic pole position and the second estimated magnetic pole position is selected, and the selected estimated magnetic pole position is set as an initial magnetic pole position. The control device according to claim 1, wherein the control device is determined as follows.
4. The drive unit is
   The control device according to claim 2, wherein the plurality of coils are energized using an excitation pattern corresponding to a magnetic pole position having a predetermined deviation from the first estimated magnetic pole position.
5. The drive unit is
   When the drive unit energizes using the excitation pattern, the current applied to the plurality of coils is increased at regular time intervals from the initial current value according to the minimum load in the linear motor,
   The current application to the plurality of coils is stopped when the current value applied to the plurality of coils reaches a maximum current value corresponding to a maximum load in the linear motor. The control device according to claim 4.
6. The drive unit is
   The current of the maximum current value according to the maximum load in the linear motor is energized in a pulse shape when energizing the excitation pattern to the plurality of coils. The control apparatus in any one.
7. A magnet unit including a plurality of magnets in which N-pole and S-pole magnetic poles are alternately arranged in the axial direction, and an armature including a plurality of coils, and the plurality of coils provided in the armature A control method in a control apparatus for a linear motor in which one of the armature or the magnet unit linearly moves in the axial direction by a magnetic field generated by passing a current and a magnetic field generated by a plurality of magnets provided in the magnet unit Because
   A signal corresponding to the direction of the magnetic flux lines of the magnetic field generated by the plurality of magnets is received from the magnetic sensor provided in the armature so as to face the plurality of magnets provided in the magnet unit, and the received signal is A magnetic pole position calculating step for calculating a first estimated magnetic pole position in response,
   A determination step of selecting any one of a second estimated magnetic pole position that is 180 ° different from the first estimated magnetic pole position and the first estimated magnetic pole position, and determining the selected estimated magnetic pole position as an initial magnetic pole position; A control method characterized by comprising:

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