JP3312218B2 - Magnetic bearing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic bearing device.

[0002]

2. Description of the Related Art Conventionally, as a magnetic bearing device, a five-degree-of-freedom control type magnetic bearing device including one axial magnetic bearing and two radial magnetic bearings for non-contactly supporting a rotating body is known.

In such a five-degree-of-freedom control type magnetic bearing device, a control system for controlling a translational motion and a tilting motion related to the center of gravity of a rotating body is known. Of these, the translational movement of the rotating body in the axial direction is independently controlled by the axial magnetic bearing. The translational movement and the tilting movement of the rotating body in the radial direction are controlled by first and second radial magnetic bearings arranged at two positions in the axial direction of the rotating body. In this control system in the radial direction, the translational motion and the tilting motion are controlled separately as follows. That is, the first and second position detecting devices arranged at two positions in the axial direction of the rotating body detect the radial position of the rotating body, and the rotating body is detected from the outputs of the first and second position detecting devices. The radial displacement of the center of gravity and the amount of tilt around the center of gravity are calculated, and a translational motion control signal is output from the translational motion control circuit so that the amount of displacement of the center of gravity of the rotating body becomes zero. A tilt motion control signal whose amount becomes zero is output from the tilt motion control circuit, and the first and second electromagnet drive circuits (power amplifiers) output the first and second electromagnet drive circuits based on the outputs of the translation motion control circuit and the tilt motion control circuit. And the electromagnet of the second magnetic bearing is driven.

[0004]

In the magnetic bearing device as described above, in order to control the translational motion and the tilting motion in the radial direction completely separately, the first and the second motors generated by the output of the translational motion control circuit are required. No new tilting motion is generated by the attractive force of the electromagnet of the second magnetic bearing, and a new translational motion is generated by the attractive force of the electromagnets of the first and second magnetic bearings generated by the output of the tilting motion control circuit. It is necessary not to let it. However, in the conventional magnetic bearing device, the output of the translational motion control circuit and the output of the tilting motion control circuit are input to both the first and second electromagnet drive circuits at a ratio of 1: 1. Therefore, depending on the geometric conditions due to the positional relationship between the center of gravity of the rotating body and the radial magnetic bearing, and the magnetic conditions due to the attractive force coefficient of the electromagnet of the radial magnetic bearing and the steady current value, the control of the translational motion and the tilting motion Control may affect each other and may not be completely separated.

An object of the present invention is to solve the above problems,
It is an object of the present invention to provide a magnetic bearing device that can completely control the translational motion and the tilting motion of a rotating body without being affected by geometrical conditions and magnetic conditions.

[0006]

SUMMARY OF THE INVENTION A magnetic bearing device according to the present invention includes first and second radial magnetic bearings which are disposed at two positions in the axial direction of a rotating body and support the rotating body in a non-contact manner. First and second position detecting means arranged at two positions in the axial direction to detect the radial position of the rotating body, and radial displacement of the center of gravity of the rotating body based on the output of the first and second position detecting means Displacement amount calculating means for calculating the amount, tilt amount calculating means for calculating the tilt amount around the center of gravity of the rotating body from the output of the first and second position detecting means, and the displacement amount of the center of gravity of the rotating body becomes zero. Motion control means for outputting a simple translational motion control signal, tilting motion control means for outputting a tilting motion control signal such that the amount of tilting around the center of gravity of the rotating body becomes zero, and the translational motion control means and the tilting motion A magnetic bearing apparatus having a first and second electromagnet driving means for driving each of the electromagnets of the first and second magnetic bearings based on the output of the control means, the first electromagnetic drive means includes a multiplier Through
Based on the output of the translational motion control means and the output of the tilt motion control means, which are input at a one-to-one ratio.
A second electromagnet driving means for driving an electromagnet of the air bearing;
Is Ru multiplied by the first coefficient to the output of the translational movement control means
A signal output from the first multiplier, the output from the second multiplier Ru multiplied by a second coefficient to the output of the tilt motion control means
Drive the electromagnet of the second magnetic bearing based on the received signal
And, the first coefficient, the suction force coefficient of the electromagnets of the first and second magnetic bearings, the steady value of current supplied to the electromagnets of the first and second magnetic bearing, and the center of gravity of the rotary body The first coefficient is determined based on a distance from a position to the first and second magnetic bearings, and the second coefficient is an attractive force coefficient of the electromagnet of the first and second magnetic bearings, and the first and second Is determined based on a steady-state current value supplied to the electromagnet of the magnetic bearing.

For example, the attraction coefficient of the electromagnet of the first magnetic bearing is K1, the attraction coefficient of the electromagnet of the second magnetic bearing is K2, the steady current value supplied to the electromagnet of the first magnetic bearing. I01, the steady-state current value supplied to the electromagnet of the second magnetic bearing is I02, the distance from the center of gravity of the rotating body to the first radial magnetic bearing is M1, the second radial magnetic bearing is When the distance to M2 is M2, the first coefficient A1 is A1 = (K1 / K2). (I01 / I02). (M1 / M2), and the second coefficient A2 is A2 = ( K1 / K2) · (I01 / I02) der is, the second electromagnetic drive means, the translation system
From the signal obtained by multiplying the output of the control means by the first coefficient,
A signal obtained by multiplying the output of the tilting motion control means by the second coefficient.
The electromagnet of the second magnetic bearing is driven based on the signal obtained by subtracting
You moving.

[0008]

The first electromagnet driving means is via a multiplier.
Of the first magnetic bearing based on the output of the translational motion control means and the output of the tilting motion control means, which are input at a one-to-one ratio .
Driving the electromagnet, the second electromagnet driving means, out of the first multiplier Ru multiplied by a first coefficient to an output of the translation control means
The signal which is force, based on a signal output from the second multiplier Ru multiplied by a second coefficient to the output of the tilt motion control means
To drive the electromagnet of the second magnetic bearing so that the first coefficient is
The attraction force coefficients of the electromagnets of the first and second magnetic bearings,
And the steady-state current value supplied to the electromagnets of the second magnetic bearing and the distance from the position of the center of gravity of the rotating body to the first and second magnetic bearings, and the second coefficient is
Since it is determined based on the attraction force coefficients of the electromagnets of the first and second magnetic bearings and the steady-state current value supplied to the electromagnets of the first and second magnetic bearings, only two multipliers are required.
With the simple configuration used , translation is not affected by geometric conditions due to the positional relationship between the center of gravity of the rotating body and the radial magnetic bearing, and the magnetic conditions due to the attractive force coefficient of the electromagnet of the radial magnetic bearing and the steady-state current value. Movement and tilting movement can be controlled completely separately.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a five-degree-of-freedom control type magnetic bearing device and a main part of the control device. In the following description, up, down, left, and right refer to FIG.

The magnetic bearing device comprises one axial magnetic bearing (not shown) for supporting the rotating body (1) in a non-contact manner and two
And two radial magnetic bearings (2) and (3).

The axial magnetic bearing supports the rotating body (1) in the Z-axis direction (vertical direction). The radial magnetic bearings (2) and (3) support the rotating body (1) in the radial direction. In each of the radial magnetic bearings (2) and (3), the rotating body (1) is placed in the X-axis direction (left-right direction) orthogonal to the Z-axis.
(X-axis direction magnetic bearing), Z-axis and X-axis
There is a portion that is supported in the Y-axis direction orthogonal to the axis (the direction orthogonal to the plane of FIG. 1) and a (Y-axis direction magnetic bearing). FIG. 1 shows the X-axis direction magnetic bearings (4) and (5). Have been. The upper radial magnetic bearing (2) will be referred to as a first radial magnetic bearing, and the lower radial magnetic bearing (3) will be referred to as a second radial magnetic bearing. Also, the upper X-axis direction magnetic bearing
(4) is simply the first magnetic bearing, the lower X-axis magnetic bearing (5)
Is simply referred to as a second magnetic bearing. The radial magnetic bearings (2) and (3) include a part that controls the X-axis magnetic bearings (4) and (5) (an X-axis controller) and a part that controls the Y-axis magnetic bearing. 1 shows an X-axis direction control device (6).

An X-axis direction magnetic bearing (4) shown in FIG.
(5) and the X-axis direction control device (6) control the translational movement and the tilting movement of the rotating body (1) in the XZ plane separately. Here, the translational motion is the motion of the center of gravity of the rotating body (1) in the X-axis direction, and the tilting motion is the rotating body (1) centered on an axis passing through the center of gravity of the rotating body (1) and parallel to the Y axis. ).

Each of the X-axis magnetic bearings (4) and (5) includes a rotating body (1).
Are provided between the pair of electromagnets (4a), (4b), (5a), and (5b). A pair of electromagnets (4a) and (4b) of the first magnetic bearing (4) is used as a first electromagnet and a second magnetic bearing (5).
The pair of electromagnets (5a) and (5b) is referred to as a second electromagnet.

The electromagnets (4a) (4) of the X-axis direction magnetic bearings (4) (5)
b) In the vicinity of (5a) (5b), a pair of position sensors (7a) (7b) (8a) (8
b) is arranged so as to sandwich the rotating body (1) from both sides in the X-axis direction. The upper pair of position sensors (7a) and (7b) is referred to as a first position sensor, and the lower pair of position sensors (8a) and (8b) are referred to as a second position sensor.

The outputs of the pair of first position sensors (7a) and (7b) are input to a first subtractor (10), which calculates the X-axis displacement X1 of the upper portion of the rotating body (1). . The outputs of the pair of second position sensors (8a) and (8b) are input to a second subtractor (11), which calculates the X-axis displacement X2 of the lower portion of the rotating body (1). The first position sensors (7a) and (7b) and the first subtractor (10) constitute first position detecting means for detecting the position of the upper portion of the rotating body (1) in the X-axis direction. The second position sensors (8a) and (8b) and the second subtractor (11) constitute second position detecting means for detecting the position of the lower portion of the rotating body (1) in the X-axis direction.

The driving signal C1 for the first electromagnets (4a) and (4b), which is the first output of the control device (6), constitutes first electromagnet driving means for driving the right first electromagnet (4a). Input to the first power amplifier (12) and via the inverter (13)
The signal is input to a second power amplifier (14) constituting first electromagnet driving means for driving the first electromagnet (4b) on the left side. 1st electromagnet
When the drive signal C1 is zero, a constant steady current is passed through the coils (4a) and (4b), and the current value flowing through these coils is controlled by the drive signal C1.
The drive signal C2 of the second electromagnets (5a) and (5b), which is the second output of the control device (6), is used to drive the second electromagnet (5a) on the right side.
Input to the third power amplifier (15) constituting the electromagnet driving means of the present invention, and the fourth power constituting the second electromagnet driving means for driving the second electromagnet (5b) on the left side via the inverter (16). Input to the amplifier (17). When the drive signal C2 is zero, a constant steady current is also flowing through the coils of the second electromagnets (5a) and (5b), and the current value flowing through these coils is controlled by the drive signal C2. I have. By controlling the value of the current flowing through the coils of the first and second electromagnets (4a) (4b) (5a) (5b), the translational motion and the tilting motion of the rotating body (1) are separated. Controlled.

FIG. 2 shows a rotating body (1), electromagnets (4a), (4b) and (5a).
(5b) and the positional relationship between the position sensors (7a), (7b), (8a), and (8b).

In FIG. 2, the center of gravity of the rotating body (1) is represented by (G). The distance in the axial direction from the center of gravity (G) to the first electromagnets (4a) and (4b) is M1, the distance in the same direction from the second electromagnets (5a) and (5b) is M2, and the first position sensor (7a) ( The distance in the same direction up to 7b) is S1, and the distance in the same direction up to the second position sensors (8a) and (8b) is S2. Further, the displacement amount of the center of gravity (G) in the X-axis direction is represented by XG, the amount of inclination around the center of gravity (G) of the rotating body (1) on the XZ plane, that is, the displacement of the axis parallel to the Y axis passing through the center of gravity (G). The amount of inclination of the rotating body (1) is represented by θY.

FIG. 3 shows an example of the control device (6).

In FIG. 3, the output X1 of the first subtractor (10)
Is multiplied by {S2 / (S1 + S2)} by the first amplifier (20) and input to the first adder (21), and the output X2 of the second subtractor (11) is {S1 / (S1 + S2)｝
The displacement is input to the first adder (21), and the first adder (21) adds them to calculate the displacement XG.
In the first and second amplifiers (20) and (22), X1 and X1
2 is multiplied by a coefficient based on the distances S1 and S2 from the center of gravity (G) to the position sensors (7a) (7b) (8a) (8b), and these distances S1 and S2 are not equal to each other. Even in this case, the displacement XG can always be calculated accurately. First and second amplifiers (20) and (22) and a first adder (21)
Is a rotator from the outputs of the first and second subtracters (10) and (11).
The displacement amount calculating means for calculating the displacement amount XG of (1) is constituted. The outputs of the first and second subtracters (10) and (11) are also:
An input is made to two input terminals of the third subtractor (23), whereby the inclination θY of the rotating body (1) is calculated. Third subtractor (2
3) is a rotator based on the outputs of the first and second subtracters (10) and (11).
The tilt amount calculating means for calculating the tilt amount θY of (1) is constituted. The output XG of the first adder (21) is input to a translation PID control circuit (24) which constitutes the translation control means, and from this circuit (24) a translation motion control signal such that the displacement XG becomes zero. D1 is output. The output .theta.Y of the third subtractor (23) is a tilt motion PID control circuit (2
The circuit (25) outputs a tilt motion control signal D2 such that the tilt amount θY becomes zero. Outputs D1 and D2 of the two control circuits (24) and (25) are input to two input terminals of a second adder (26), respectively.
A drive signal C1 for the electromagnets (4a) and (4b) is output. The translation control signal D1 is passed through a third amplifier (27) to a fourth subtractor (28).
And the tilting motion control signal D2 is input to the fourth subtractor (28) via the fourth amplifier (29). Third amplifier
A signal obtained by multiplying the translational motion control signal D1 by the first coefficient A1 is output from (27), and a signal obtained by multiplying the tilt motion control signal D2 by the second coefficient A2 is output from the fourth amplifier (29). You. Then, in the fourth subtractor (28), the tilting motion control signal D2 is converted from the signal obtained by multiplying the translational motion control signal D1 by A1 to A1.
The doubled signal is subtracted, and a drive signal C2 for the second electromagnets (5a) (5b) is output.

The first coefficient A1 and the second coefficient A2 are
It is expressed as follows.

A1 = (K1 / K2) (I01 / I02) ・
(M1 / M2) A2 = (K1 / K2). (I01 / I02) where K1 is the attraction force coefficient of the first electromagnets (4a) and (4b), K2
Is the attractive force coefficient of the second electromagnet (5a) (5b), and I01 is the first electromagnet.
(4a) The steady current value supplied to (4b), I02 is the second electromagnet (5
a) It is a steady current value supplied to (5b).

In the magnetic bearing device as described above, the first and second electromagnets (4a) (4b) (4b) (4a) generated by the translational motion control signal D1 in order to completely control the translational motion and the tilting motion. 5a) (5b) No new tilting motion is generated by the attraction force, and the attraction force of the first and second electromagnets (4a) (4b) (5a) (5b) generated by the tilting motion control signal D2. It is necessary that no translational motion be generated.

The first generated by the translation control signal D1
The condition for preventing a new tilting motion from being generated by the attraction force of the second electromagnets (4a) (4b) (5a) (5b) is that the first electromagnet (4) is proportional to the control current value IC1 based on the translational motion control signal D1.
a) The attraction force F1 of the second electromagnets (5a) and (5b) which is proportional to the attraction force F1 of (4b) and the control current value IC2 based on the translation control signal D1.
2 means that there is no moment to generate a tilt. When the relationship between IC1 and IC2 that satisfies such a condition is obtained, the following equation is obtained.

IC2 / IC1 = (K1 / K2). (I01 / I
02) · (M1 / M2) The right side of this equation is equal to the first coefficient A1. In the magnetic bearing device described above, the translation control signal D1 is supplied to the second adder (26) which outputs the drive signal C1 for the first electromagnets (4a) (4b).
As it is, and the drive signal C2 for the second electromagnets (5a) (5b)
The translational motion control signal D1 is supplied to the fourth subtractor (28) which outputs
Since the input is multiplied by 1, the condition of the above expression is satisfied. Therefore, no new tilting motion is generated by the attractive force of the first and second electromagnets (4a) (4b) (5a) (5b) generated by the translational motion control signal D1.

The first generated by the tilting motion control signal D2
The condition for preventing a new translational motion from being generated by the attractive force of the second electromagnets (4a) (4b) (5a) (5b) is that the first electromagnet (4) is proportional to the control current value IC1 based on the tilting motion control signal D2.
a) The attraction force F1 of the second electromagnets (5a) and (5b) which is proportional to the attraction force F1 of (4b) and the control current value IC2 based on the tilting motion control signal D2.
2 is to be balanced. When the relationship between IC1 and IC2 that satisfies such a condition is obtained, the following equation is obtained.

IC2 / IC1 = (K1 / K2) · (I01 / I02) The right side of this equation is equal to the second coefficient A2. In the magnetic bearing device described above, the tilt motion control signal D2 is supplied to the second adder (26) which outputs the drive signal C1 for the first electromagnets (4a) (4b).
As it is, and the drive signal C2 for the second electromagnets (5a) (5b)
Is output to the fourth subtractor (28) which outputs
Since it is input twice, it satisfies the condition of the above formula. Therefore, no new translational motion is generated by the attractive force of the first and second electromagnets (4a) (4b) (5a) (5b) generated by the tilt motion control signal D2.

As described above, in the above magnetic bearing device, a new tilting motion is generated by the attraction force of the first and second electromagnets (4a) (4b) (5a) (5b) generated by the translational motion control signal D1. And no new translational motion is generated by the attractive force of the first and second electromagnets (4a) (4b) (5a) (5b) generated by the tilting motion control signal D2.
The translation and tilting movements can be controlled completely separately.

FIG. 4 shows a modification of a part of the control device (6).

In this case, the translational motion control signal D1 is inputted to the fourth subtractor (28) via the first variable amplifier (30) and the second variable amplifier (31), and the tilt motion control signal D2 is inputted to the first subtractor (28). The signal is input to the fourth subtractor (28) via the variable amplifier (30). First
A signal obtained by multiplying the translational motion control signal D1 and the tilting motion control signal D2 by a second coefficient A2 is output from the variable amplifier (30), and the output of the first variable amplifier (30) is output from the second variable amplifier (31). Is further multiplied by a coefficient B1.

The coefficient B1 is expressed as follows.

B1 = M1 / M2 In each of the variable amplifiers (30) and (31), the magnitudes of the coefficients A2 and B1 can be arbitrarily adjusted. The others are shown in FIG.
Is the same as The product of coefficient A2 and coefficient B1 is
It is equal to the first coefficient A1. Therefore, also in this case, similarly to the case of the above-described embodiment, the signal obtained by multiplying the tilt motion control signal D2 by A2 from the signal obtained by multiplying the translation motion control signal D1 by A1 is subtracted by the fourth subtractor (28). 2 electromagnets (5a)
This is output as the drive signal C2 in (5b). Also, the rotating body
Even if the distances M1 and M2 from the center of gravity (G) of (1) to the electromagnets (4a) (4b) (5a) (5b) change, the coefficient B of the second variable amplifier (31) changes.
You only need to adjust 1.

FIG. 5 shows another modification of a part of the control device (6).

This corresponds to the first variable amplifier (30) in FIG.
Are moved to the subsequent stage of the fourth subtractor (28). The drive signal C2 for the second electromagnets (5a) and (5b) is output from the first variable amplifier (30). Others are the same as those in FIG. In this case, as in the case of the above-described embodiment, the signal obtained by multiplying the translational motion control signal D1 by A1 is used to obtain the tilt motion control signal
The signal obtained by subtracting the signal obtained by multiplying 2 by A2 is the second electromagnet (5a).
This is output as the drive signal C2 in (5b).

As for the Y-axis direction magnetic bearing and the Y-axis direction control device, the control direction is changed from the X-axis direction to the Y-axis direction. The configuration is the same as that of the device (6).

[0037]

According to the magnetic bearing device of the present invention, as described above, the translation of the rotating body is effected by the simple configuration using only two multipliers without being affected by the geometrical condition and the magnetic condition. The movement and the control of the tilting movement can be completely separated.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of a magnetic bearing showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a positional relationship among a rotating body of a magnetic bearing device, an electromagnet of a magnetic bearing, and a position sensor.

FIG. 3 is a block diagram illustrating an example of an X-axis direction control device.

FIG. 4 is a block diagram showing a modification of a part of the X-axis direction control device.

FIG. 5 is a block diagram showing another modified example of a part of the X-axis direction control device.

[Explanation of symbols]

 (1) Rotating body (2) First radial magnetic bearing (3) Second radial magnetic bearing (4) X-axial magnetic bearing (4a) (4b) Electromagnet (5) X-axial magnetic bearing (5a (5) Electromagnet (6) X-axis direction controller (7a) (7b) First position sensor (8a) (8b) Second position sensor (10) First subtractor (11) Second subtractor (12) First power amplifier (13) Inverter (14) Second power amplifier (15) Third power amplifier (16) Inverter (17) Fourth power amplifier (20) First amplifier (21) First adder (22) Second 2 amplifier (23) 3rd subtractor (24) PID control circuit for translational motion (25) PID control circuit for tilting motion (26) 2nd adder (27) 3rd amplifier (28) 4th subtractor (29) 4th amplifier (30) 1st variable amplifier (31) 2nd variable amplifier

Claims (2)

(57) [Claims] 1. First and second radial magnetic bearings arranged at two positions in the axial direction of a rotating body and supporting the rotating body in a non-contact manner, the first and second radial magnetic bearings being arranged at two positions in the axial direction of the rotating body. First and second position detection means for detecting a position in the radial direction; displacement amount calculation means for calculating a radial displacement amount of the center of gravity of the rotating body from an output of the first and second position detection means; And a tilt amount calculating means for calculating a tilt amount around the center of gravity of the rotating body from an output of the second position detecting means, and a translational movement controlling means for outputting a translational movement control signal such that the displacement amount of the center of gravity of the rotating body becomes zero. A tilting motion control unit that outputs a tilting motion control signal such that the tilt amount around the center of gravity of the rotating body becomes zero; and the first and second tilting motion control units based on outputs of the translational motion controlling unit and the tilting motion control unit. Magnetic A magnetic bearing apparatus having a first and second electromagnet driving means for driving the electromagnets of the bearings respectively, said first electromagnetic drive means, without passing through a multiplier
A first magnetic axis based on the output of the translational motion control means and the output of the tilt motion control means input at a one-to-one ratio ;
Drives the receiving of the electromagnet, the second electromagnet driving means, first of Ru multiplied by a first coefficient to the output of the translational movement control means
A signal output from the multiplier, output from the second multiplier Ru multiplied by a second coefficient to the output of the tilt motion control means
Driving the electromagnets of the second magnetic bearing based on the signals, the first coefficient is the attraction force coefficient of the electromagnets of the first and second magnetic bearings, and the electromagnets of the first and second magnetic bearings And the distance from the position of the center of gravity of the rotating body to the first and second magnetic bearings, and the second coefficient is determined by the first and second magnetic bearings. Of the attraction force of the electromagnet of
The magnetic bearing device is determined based on a steady-state current value supplied to an electromagnet of the second magnetic bearing. 2. The attraction force coefficient of the electromagnet of the first magnetic bearing is K1, and the attraction force coefficient of the electromagnet of the second magnetic bearing is K1.
2. The steady-state current value supplied to the electromagnet of the first magnetic bearing is I01, the steady-state current value supplied to the electromagnet of the second magnetic bearing is I02, and the first radial is determined from the position of the center of gravity of the rotating body. When the distance to the directional magnetic bearing is M1 and the distance to the second radial magnetic bearing is M2, the first coefficient A1 is: A1 = (K1 / K2) · (I01 / I02) · (M1 / M2) a and, the second coefficient A2 is, A2 = (K1 / K2) · (I01 / I02) der is, the second electromagnetic drive means of the translational movement control means
From the signal obtained by multiplying the output by the first coefficient,
A signal obtained by multiplying the output of the control means by the second coefficient is subtracted.
2. The magnetic bearing device according to claim 1, wherein the electromagnet of the second magnetic bearing is driven based on the signal .