JP3528001B2 - Control device for magnetic bearing - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention eliminates the influence of a forward rotation component and a rear rotation component of a primary vibration mode natural vibration component of a rotating body due to a gyro action. The present invention relates to a magnetic bearing control device. 2. Description of the Related Art As a control device for a magnetic bearing of this type, a control device as shown in FIG. 3 is conventionally known. FIG. 3 shows a pair of electromagnets (2) and (3) of a radial magnetic bearing for supporting a rotating body (1) in a non-contact manner, and one of its control devices.
An example is shown. In FIG. 3 , a rotation sensor (4) for outputting a pulse signal corresponding to the rotation speed N around a rotating body (1).
And its output is input to the FV conversion circuit (5). The conversion circuit (5) converts the rotation speed N into a voltage signal (rotation speed detection signal) VN proportional thereto. A pair of position sensors (6) and (7) are provided around the rotating body (1) to detect the radial position of the rotating body (1) in correspondence with the electromagnets (2) and (3). ing. Two position sensors (6) (7)
Is subtracted by a first subtraction circuit (8), and the output of the first subtraction circuit (8) is subtracted from a fixed reference signal (usually 0) by a second subtraction circuit (9). From (9), a displacement detection signal δ corresponding to the radial displacement of the rotating body (1) is output. A voltage variable band elimination filter (first filter) (10) for the leading component and a voltage variable band elimination filter (second filter) (11) for the trailing component comprise a PID control circuit (12).
And a second subtraction circuit (9).
The displacement detection signal δ output from the subtraction circuit (9) is input to the input terminal of the second filter (11), and the output of the second filter (11) is input to the input terminal of the first filter (10). 1 filter (1
The output of (0) is input to the PID control circuit (12). And P
The output of the ID control circuit (12) is input to the first power amplifier (13), and is output to the second power amplifier (1) via the inverting amplifier (14).
5), and the power amplifiers (13) and (15) drive the electromagnets (2) and (3), respectively. The output of the FV conversion circuit (5) is input to the input terminals of a first function generation circuit (16) and a second function generation circuit (17), and the output of the first function generation circuit (16) is The second function generating circuit (17) is connected to the center frequency setting voltage input terminal of one filter (10).
Are input to the center frequency setting voltage input terminals of the second filter (11). [0007] Two functions generator (16) (17), using the relationship shown in FIG. 4, and outputs a voltage corresponding to the rotational speed detection signal VN. In FIG. 4 , the horizontal axis represents the rotation speed N of the rotating body (1), and the vertical axis represents the natural frequency f of the rotating body (1). (F) is a forward rotation component fF of the primary bending mode natural vibration component of the rotating body (1) due to the gyro action, and (B) is a backward rotation component f.
B is shown. The forward rotation component fF increases as the rotation speed N increases, and is approximated by one straight line (L1). The backward rotation component fB decreases as the number of rotations N increases, and one straight line (L
It is approximated by 2). The first function generator (16) is a straight line (L1)
A voltage corresponding to the number of revolutions N is output using the relationship, and the center frequency of the first filter (10) is set to a frequency corresponding to the output voltage. The second function generation circuit (17) outputs a voltage corresponding to the rotation speed N using the relationship of the straight line (L2), and the center frequency of the second filter (11) is set to a frequency corresponding to the output voltage. . As a result, the backward component fB is removed from the displacement detection signal δ by the second filter (11), and the forward component fF is removed by the first filter (10), and this is input to the PID control circuit (12). The power amplifiers (13) and (15) control the electromagnets (2) and (3) based on the output of the PID control circuit (12). In the above-described conventional magnetic bearing control device, the forward and backward components of the natural vibration component are each approximated by one straight line, and a filter ( 10) Since the center frequency of (11) is set,
There are the following problems. [0009] change in the previous Ri components fF and Atomawari component fB by rotational speed variation is not linear, as shown in FIG. 4, the curved. Therefore, when these are approximated by one straight line (L1) (L2), a portion where the forward rotation component fF and the backward rotation component fB do not coincide with the straight lines (L1) and (L2) occurs.
In such a portion, an error occurs between the center frequency of the filters (10) and (11) and the leading and trailing components. Therefore, it may not be possible to remove the influence of the forward rotation component and the backward rotation component in a desired range of the rotation speed. 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 control device that can reliably remove the influence of the forward rotation component and the backward rotation component in a desired range of the rotation speed. According to the present invention, there is provided a magnetic bearing control device comprising: a rotational speed detecting means for detecting a rotational speed of a rotating body; a displacement detecting means for detecting a displacement of the rotating body; A center frequency variable band elimination filter for removing a leading component and a trailing component of a primary bending mode natural vibration component of a rotating body due to a gyro action, and a center frequency of the band elimination filter is set based on a rotation speed detection signal. the center frequency setting means, and the rotating body on the basis of the output of the displacement detection signals or band-stop filter comprises a control circuit for controlling the non-contact supporting electromagnets, the center frequency setting means, the rotating body rotating speed in the vicinity rating In the linear approximation range
Has a variable center frequency pattern which is linearly approximated changes in previous Ri components and Atomawari component of the natural oscillation component to the actual rotational speed state, and are not to set the center frequency of the band reject filter on the basis of this pattern, the control circuit But the rotation of the rotating body
If the number of turns is not within the above linear approximation range, the displacement detection signal
The electromagnet is controlled on the basis of
Based on the output of the band reject filter if it is within the similar range
And controls the electromagnet . According to the present invention, the center frequency setting means is provided near the rated rotation speed of the rotating body.
It has a center frequency variable pattern that linearly approximates the change in the forward and backward components of the natural vibration component with respect to the rotation speed in the nearby linear approximation range, and sets the center frequency of the band elimination filter based on this pattern. Therefore , in the linear approximation range near the rated speed of the rotating body ,
The center frequency of the band elimination filter can be made to exactly match the leading component and the trailing component, so that the effects of the leading component and the trailing component can be reliably removed. The rotation speed of the rotating body is close to a straight line near the rated rotation speed.
If not within the similar range, the leading and trailing components
The effect is not removed, but it is actually a leading component and a trailing component
The effect of the component becomes a problem near the rated speed of the rotating body.
Yes, and within the linear approximation range including this,
Components and back-flow components can be reliably removed.
So that, as a whole, the forward and backward components
Stable control that is not affected by minutes can be performed . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 and FIG.
Description will be given of the actual施例. Also in this embodiment, a pair of electromagnets (2) and (3) of a radial magnetic bearing for supporting the rotating body (1) in a non-contact manner
And an example of a control device thereof. The same parts as those of the conventional example are denoted by the same reference numerals. In the embodiment of FIG. 1 , the second subtraction circuit
(9) A switching circuit (20) is provided between the first filter (10) and the PID control circuit (12). The displacement detection signal δ output from the second subtraction circuit (9) is input to the second filter (11) and also to the first switching contact (20a) of the switch circuit (20), and the first filter (10 ) Is input to the second switching contact (20b) of the switch circuit (20). And the common contact (20c) of the switch circuit (20) is PI
It is connected to the input terminal of the D control circuit (12). The first function generating circuit (21) and the second function generating circuit (22) are different from the conventional function generating circuits (16) and (17).
A voltage corresponding to the rotation speed detection signal VN is output using a center frequency variable pattern as shown in FIG. The first function generating circuit (21) is configured to provide a fixed range (linear approximation range) between N1 and N2 near the rated speed of the rotating body (1) in the entire range of the rotating speed N of the rotating body (1). Only in (A), there is a first center frequency variable pattern (first pattern) in which the forward rotation component fF is approximated by one straight line (L3), and the voltage corresponding to the rotation speed N is changed using this pattern. Output to filter (10). The second function generating circuit (22) has a second center frequency variable pattern (second pattern) in which the backward component fB is approximated by one straight line (L4) only in the straight line approximation range (A). To output a voltage corresponding to the rotation speed N to the second filter (11). The output of the rotation sensor (4) is output from an FV conversion circuit (5).
And input to the switching circuit (23), and the output of the switching circuit (23) outputs the switching circuit (2
0) is switched. That is, when the rotation speed N is not within the linear approximation range (A), the switch circuit (20) is switched to the first switching contact (20a) side, and when the rotation speed N is within the linear approximation range (A). The switch circuit (20) is switched to the second switching contact (20b) side. The rotation sensor (4) and the FV conversion circuit (5) constitute a rotation speed detecting means for detecting the rotation speed N of the rotating body (1). Position sensors (6) (7), first and second
The subtraction circuits (8) and (9) constitute a displacement detecting means for detecting a radial displacement of the rotating body (1). Further, the first and second function generating circuits (21) and (22) constitute center frequency setting means for setting the center frequencies of the filters (10) and (11) based on the rotation speed detection signal VN, respectively. . When the rotational speed N of the rotating body (1) is not within the linear approximation range (A), the switch circuit (20) is switched to the first switching contact (20a) side as described above, and the common contact ( 20c) is connected to the first switching contact (20a), so that the first filter
The output of (10) is not input to the PID control circuit (12), and the displacement detection signal δ from the second subtraction circuit (9) is input to the PID control circuit (12) as it is. Then, the electromagnets (2) and (3) are controlled based on the displacement detection signal δ. When the rotational speed N of the rotating body (1) is within the linear approximation range (A), the switch circuit (20) is switched to the second switching contact (20b) side as described above, and the common contact ( 20c) is connected to the second switching contact (20b), the displacement detection signal δ is not directly input to the PID control circuit (12), and the output of the first filter (10) is output to the PID control circuit (12 ). At this time, as described above, the first function generation circuit
(21) outputs a voltage corresponding to the number of revolutions N using the first pattern, and outputs the first filter to a frequency corresponding to the output voltage.
The center frequency of (10) is set. Further, the second function generating circuit (22) outputs a voltage corresponding to the rotation speed N using the second pattern, and the center frequency of the second filter (11) is set to a frequency corresponding to the output voltage. Therefore, a signal obtained by removing the forward rotation component fF and the backward rotation component fB from the displacement detection signal δ is input to the PID control circuit (12), and the electromagnets (2) and (3) are controlled based on the signal. The first and second patterns in the first and second function generating circuits (21) and (22) have a forward rotation component fF and a forward rotation component only in a linear approximation range (A) near the rated rotation speed of the rotating body (1). Since the backward component fB is a linear approximation, the error between the forward component fF and the backward component fB and the first and second patterns is small.
The effects of F and the trailing component fB can be reliably removed. When the rotational speed N is not within the linear approximation range (A), the influence of the forward rotation component fF and the backward rotation component fB is not removed, but the influence of the forward rotation component fF and the rearward rotation component fB actually becomes a problem. Is near the rated rotation speed of the rotating body (1), and within the linear approximation range (A) including this, the influence of the forward rotation component fF and the backward rotation component fB can be reliably removed as described above. As a whole, stable control that is not affected by the forward rotation component fF and the backward rotation component fB can be performed. According to the magnetic bearing control device of the present invention, as described above, the linear approximation near the rated rotational speed of the rotating body is achieved.
The influence of the previous Ri components and Atomawari components of the first-order bending mode natural frequency component of the rotation member by the gyro effect can be reliably removed in a range, thereby, before the whole
Stable control that is not affected by circling components and backward components
Control is possible to ing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an electrical block diagram of a main portion of the control device of the radial magnetic bearing shown real施例of the present invention. FIG. 2 is a graph showing a relationship between a rotation speed of a rotating body, a forward component and a backward component of a natural vibration component, and a center frequency variable pattern in the embodiment of FIG . 1 ; FIG. 3 is an electric block diagram of a main part of a control device for a radial magnetic bearing showing a conventional example. FIG. 4 is a graph showing a relationship between a rotation speed of a rotating body, a forward rotation component and a backward rotation component of a natural vibration component, and a straight line approximating these components in a conventional example. [Explanation of symbols] (1) Rotating body (2) (3) Electromagnet (4) Rotation sensor (5) FV converter (6) (7) Position sensor (8) (9) Subtraction circuit (10) ( 11) Voltage variable band elimination filter (12) PID control circuit (21) (22) Function generation circuit (24) (25) Function generation circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-275814 (JP, A) JP-A-3-40792 (JP, A) JP-A-1-150015 (JP, A) JP-A 61-275 66540 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16C 32/04

Claims (1)

(57) [Claims 1] A rotation speed detecting means for detecting a rotation speed of a rotating body, a displacement detecting means for detecting a displacement of a rotating body, a primary of a rotating body by a gyro action from a displacement detection signal. A center frequency variable band elimination filter for removing a leading component and a trailing component of a bending mode natural vibration component, a center frequency setting means for setting a center frequency of the band elimination filter based on a rotation speed detection signal, and displacement detection and a control circuit for controlling an electromagnet rotating body without contact support on the basis of the output signal or band-stop filter, the center frequency setting means, the straight line in the vicinity of the rated rotation speed of the rotary body
It has a variable center frequency pattern which is linearly approximated changes in previous Ri components and Atomawari component of the natural oscillation component only with respect to the rotational speed in the approximate range state, and are not to set the center frequency of the band-stop filter based on the pattern The control circuit determines that the rotation speed of the rotating body is within the above-described linear approximation range.
Control the electromagnet based on the displacement detection signal
Band elimination when body rotation speed is within the above linear approximation range
A control device for a magnetic bearing, which controls an electromagnet based on an output of a filter .