JPH03139141A - Method and apparatus for controlling magnetic bearing - Google Patents

Abstract

PURPOSE:To accurately control a magnetic bearing by reducing to input a compensating value output from a reverse transfer function circuit at a compensation signal input point. CONSTITUTION:A compensating value corresponding to a deviation between a rotating axis at the angular position of a rotational shaft 1 output from a reverse transfer function circuit 21 and a geometrical center line is input to a subtracter 24 at a compensation signal input point, the value is subtracted to be input to a control signal in a signal path from a point of inputting a reference position signal for bringing the rotating axis of the shaft 1 into coincidence with a geometrical center line to the input points of electromagnet excited power amplifiers 4, 5 to become a correction control signal. As a result, an exciting current controlled according to the correction control signal is supplied to electromagnets 2, 3, and the shaft 1 is rotatably supported by a magnetic bearing for not generating an electromagnetic force of a vibrating period for suppressing the vibration of the shaft 1 by the influence of a resonance without bringing the rotating axis into coincidence with the geometrical center line.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and device for controlling a magnetic bearing, and more particularly to a method and device for controlling a magnetic bearing with respect to rotation of a rotating shaft subjected to various disturbances.

[Prior Art] In a magnetic bearing, two rotating shafts are usually controlled so that the geometric center line (hereinafter referred to as the geometric center line) of the outer peripheral surface of the rotating shaft corresponding to the electromagnet coincides with the rotation axis.

However, in this case, if the rotating body attached to the rotating shaft is unbalanced, for example, the geometrical center line of the rotating shaft, that is, the axis of rotation, does not coincide with the center line of inertia, resulting in undesirable vibrations.

Therefore, the above problem can be solved by controlling the magnetic bearing that supports the rotating shaft so as to rotate the rotating shaft around the center line of inertia.

In the conventional technology (see Japanese Patent Publication No. 60-14929) for aligning the axis of rotation in a magnetic bearing with the center line of inertia, a displacement detector for detecting the radial position of the rotation axis and an angular velocity detector for detecting the angular velocity are used. sine and cosine signals (sinωt) from the former displacement signal and the latter angular velocity signal.
, cosωt) to remove the periodic component of ω contained in the displacement signal.

[Problem to be solved by the invention]

The above-mentioned conventional technique for aligning the axis of rotation in a magnetic bearing with the center line of inertia requires a highly accurate analog control technique. In other words, we created extremely high-precision detectors and accurate trigonometric functions, and in order to perform even more accurate calculations, we created extremely high-precision detectors (highly stable against voltage fluctuations and temperature fluctuations, and used over a wide range of voltage during calculations). electronic circuit (with small error) is required.

Moreover, the compensation circuit for achieving stability is extremely complex and has a limited reliability.

Therefore, the above conventional technology has problems in terms of reliability and configuration.
Price wise, it is also impractical.

This invention solves the problems of the above-mentioned conventional techniques in the technology of controlling a magnetic bearing to support a rotating shaft so that it rotates around the center line of inertia. This provides practical control technology that provides highly accurate control.

Furthermore, in the rotation of a rotating shaft to which a rotating body is attached, or a rotating shaft of a fluidic device, the rotational axis is maintained at the geometric center line using conventional control methods. Vibration due to frequency or resonance frequency in the fluid working space can be directly received.

This invention solves the problems of the above-mentioned conventional techniques in the technology of controlling magnetic bearings to support rotating shafts with various conditions, and provides a practical method for controlling magnetic bearings with high precision. This technology provides advanced control technology.

[Means to solve the problem]

A magnetic bearing control method according to the present invention is a magnetic bearing in which an excitation current is controlled based on a reference position signal that aligns the geometric center line of the outer circumferential surface of a rotating shaft corresponding to an electromagnet with the rotational axis. The rotational angular position of the rotating shaft, the exciting current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet are detected, and the rotational angular velocity frequency component in the fluctuating component of the exciting current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet, Extract only the resonant frequency component of a rotating shaft including a rotating body, the resonant frequency component of a fluid working space in the case of a rotating shaft of a fluid device, or an appropriate combination thereof in parallel, and extract the exciting current, magnetic flux density of the bearing gap, or The frequency component in the fluctuation component of the electromagnetic force of the electromagnet is calculated through an inverse transfer function circuit of a closed loop transfer function from the compensation signal input point to the excitation current, the magnetic flux density of the bearing gap, or the detection signal detection point of the electromagnetic force of the electromagnet. , the output is synchronized with the rotational angular position and subtracted into the compensation signal input point to control the excitation current.

The cutting method is for magnetic bearings in which the excitation current is controlled based on a reference position signal that aligns the geometric center line of the outer circumferential surface of the rotating shaft corresponding to the electromagnet with the rotational axis. The rotational angular position, the exciting current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet are detected, and the rotating angular velocity frequency component in the varying component of the exciting current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet, and the rotating body are detected. Compensate for fluctuation components that exclude only the resonant frequency components of the rotating shaft, the resonant frequency components of the fluid working space in the case of the rotary shaft of fluid equipment, or appropriate combinations thereof in parallel. The magnetic flux density of the electromagnet or the electromagnetic force of the electromagnetic force is calculated through an inverse transfer function circuit of the closed loop transfer function up to the detection point, the output is synchronized with the rotation angle position, and the excitation current is added and input to the compensation signal input point. It's about controlling.

The magnetic bearing control device that performs the magnetic bearing control method according to the present invention includes an electromagnet provided facing the outer peripheral surface of the rotating shaft, and a first magnet that detects the rotational angular position of the rotating shaft.
A detector, a second detector that detects the exciting current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet; Magnetic flux density, or rotational angular velocity frequency component in the fluctuation component of electromagnetic force of an electromagnet, resonance frequency component of a rotating shaft including a rotating body, or resonance frequency component of a fluid working space in the case of a rotating shaft of a fluid device, or those in parallel. A filter that extracts only an appropriate combination of An inverse transfer function circuit of a closed loop transfer function up to the detection point of the excitation current, magnetic flux density of the bearing gap, or electromagnetic force of the electromagnet, and an inverse transfer function circuit of the closed loop transfer function to the detection point of the excitation current of the electromagnet, and A control circuit that aligns a geometrical centerline with the rotational axis; and an excitation current from the input point of a reference position signal that aligns the geometrical centerline of the outer peripheral surface of the rotating shaft corresponding to the electromagnet input to the control circuit with the rotational axis. and a subtracter that inputs and subtracts the compensation value output from the inverse transfer function circuit at a compensation signal input point provided at an arbitrary point on the signal path up to the command value input point.

A magnetic bearing control device for carrying out the method for controlling a cut-shaped magnetic bearing according to the present invention includes: an electromagnet provided facing the outer circumferential surface of a rotating shaft; a first detector for detecting the rotational angular position of the rotating shaft; a second pressure detector that detects the excitation current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet; and the excitation current, the magnetic flux density of the bearing gap, or A rotational angular velocity frequency component in a fluctuating component of electromagnetic force of an electromagnet, a resonant frequency component of a rotating shaft including a rotating body, a resonant frequency component of a fluid living space in the case of a rotating shaft of a fluid device, or an appropriate combination thereof in parallel. A compensation value is obtained by inputting the excitation current that is the output of the filter, the magnetic flux density of the bearing gap, or the fluctuation component after excluding the electromagnetic force of the electromagnet. A magnetic flux density or an inverse transfer function circuit of a closed loop transfer function up to the detection point of the electromagnetic force of the electromagnet, and a geometric center line of the outer peripheral surface of the rotating shaft corresponding to the electromagnet by controlling the excitation current of the electromagnet. A control circuit that aligns the rotational axis with a reference position signal input point that aligns the geometric center line of the outer peripheral surface of the rotational shaft corresponding to the electromagnet input to the control circuit with the rotational axis, and an excitation current command value input point. and an adder that adds and inputs the compensation value output from the inverse transfer function circuit at a compensation signal input point provided at an arbitrary point on the signal path up to.

[For production]

The operation and function of the magnetic bearing control device described above will be described.

In a device that aligns the axis of rotation of an unbalanced rotating shaft with the center line of inertia, control is performed according to a reference position signal to position the rotating axis at a position where the geometric center line of the rotating shaft coincides with the axis of rotation, that is, at a neutral position. The excitation current is supplied to the electromagnet, the magnetic force of the electromagnet acts, and the rotating shaft is rotatably supported at a position where the geometric center line of the rotating shaft coincides with the rotating axis, that is, a neutral position.

The rotating shaft is started one rotation, accelerated, and then enters a steady rotation state.

At this time, the rotational angular position of the rotating shaft during rotation is detected by the first detector, and an angular signal for each fixed angular position is input to the storage device. On the other hand, the excitation current to the electromagnet that fluctuates under control, the magnetic flux density in the bearing gap, or the electromagnetic force of the electromagnet,
They are respectively detected by the second detector, and the detected values are input into the storage device.

When the rotating shaft rotates once, detected values for each angular position for one rotation are stored.

The data (contents) of the storage device during one rotation of the rotating shaft is input to a filter, and all but the rotational angular velocity frequency component among the fluctuation components of the detected values during one rotation of the rotating shaft are removed, and only the rotational angular velocity frequency component is removed. is taken out. The frequency component is due to the deviation of the geometrical centerline of the rotational axis from the inertial centerline and is input to an inverse transfer function circuit and converted to the signal dimension at the corresponding compensation signal input point. It is a compensation value corresponding to the deviation between the geometric center line and the inertial center line at each angular position of the five rotation axes. The compensation value is input to the subtracter at the compensation signal input point, and as a result, the signal path from the input point of the reference position signal that aligns the rotation axis of the rotating shaft with the geometric center line to the input point of the electromagnet excitation power amplifier The compensation value is subtracted and input to the control signal in the middle to obtain a corrected control signal.

As a result, an excitation current controlled according to the correction control signal is supplied to the electromagnet, and the rotating shaft is rotated by this magnetic bearing to a position where its axis of rotation coincides with the center line of inertia instead of the position where it coincides with the geometric center line. Supported freely.

In the rotation of a rotating shaft to which a rotating body is attached or a rotating shaft of a fluid device, the axis of rotation of the rotating shaft that vibrates due to the resonance frequency of the rotating shaft including the rotating body or the resonance frequency of the fluid working space is set to the geometric center line. In the case where the data (contents) of the storage device during one revolution of the rotating shaft are input to a filter, the resonance frequency of the rotating shaft including the rotating body in the fluctuation component of the detected value during one revolution of the rotating shaft is input to the filter. component or a resonant frequency component in the fluid working space of the fluid device is removed, and only the resonant frequency component of a rotating shaft including a rotating body or the resonant frequency component in the fluid working space of the fluid device is extracted. The frequency component, which is due to the deviation of the rotational axis of the rotational axis from the geometrical centerline, is input to the inverse transfer function circuit and converted into the signal dimension at the corresponding compensation signal input point. It is a compensation value corresponding to the deviation between the axis of rotation and the geometric center line at each angular position of the axis of rotation. The compensation value is input to the subtracter at the compensation signal input point, and as a result, the signal path from the input point of the reference position signal that aligns the rotation axis of the rotating shaft with the geometric center line to the input point of the electromagnet excitation power amplifier The compensation value is subtracted and input to the control signal in the middle to obtain a corrected control signal.

As a result, an excitation current controlled according to the corrected control signal is supplied to the electromagnet, and the rotating shaft is suppressed from vibrating due to the resonance phenomenon rather than the position where its rotating axis coincides with the geometric center line. It is rotatably supported by a magnetic bearing that does not generate electromagnetic force with a vibration period of

In the cut-shaped device, in each of the above cases, a specific frequency component is extracted, but after the specific frequency component is removed,
The same effect as described above is also performed when the compensation value is added and inputted to form a correction control signal.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an apparatus for carrying out the magnetic bearing control method of the present invention will be described with reference to the drawings.

Magnetic bearings are typically multi-axis controlled, for example five-axis controlled. However, the drawing schematically shows a magnetic bearing that supports the rotating shaft 1, representing a magnetic bearing that is controlled in one direction (up and down in the illustrated example) at one location in the axial direction of the rotating shaft 1.

Electromagnets 2.3 are formed in a forked shape on the upper and lower sides of the outer peripheral surface of the horizontally placed rotating shaft 1 to which a rotating body (not shown) is attached.
are provided facing each other, the solenoids of each electromagnet 2.3 are connected to respective power amplifiers 4, 5, and excitation current is supplied from the power amplifiers 4.5, thereby forming a magnetic bearing. The rotating shaft 1 is rotatably supported by excited electromagnets 2 and 3, and is rotationally driven by a drive source (not shown).

The basic control circuit in the magnetic bearing control device described above is configured as follows.

A PID operating unit (proportional-integral-differential operating unit) 7 is connected to a reference signal source of an excitation current that should position the rotating shaft 1 at a neutral position in a normal state, and each power amplifier 4.5 It is connected to the PIDID operating section and controlled. Displacement sensors 8 and 9 are provided at the crotch of each electromagnet 2.3 to face the outer circumferential surface of the rotating shaft 1 in a non-contact state, and a sensor signal regulator IO is connected to the displacement sensors 8 and 9. , displacement sensor signals from the respective displacement sensors 8 and 9 are fed back to the reference position signal of the PIDID operation section from the reference signal source of the excitation current via the sensor signal regulator IO.

A compensation value conversion circuit as described below is connected to the above basic control circuit.

An angle scale disk 11 is attached to the rotating shaft 1.
An angle signal generator 11a is provided on the fixed side facing the angle scale disc 11, and the angle signal generator 11a is connected to the first storage device 12 and the third storage device 13, and is connected to the scale of the rotating angle scale disc 11. is read, and the angle signal of the angle scale disk 11, that is, the rotating shaft 10, is input into the first storage device 12 and the third storage device 13.

Instead of the angle scale disk 11, a magnetic disk may be used to detect the angular position with a corresponding angle signal generator.
Alternatively, the angular position of the rotating shaft 1 may be detected by a generator that generates a signal for each rotation and a pulse signal, or a rotary encoder or resolver may be used to generate a pulse signal to detect the angular position. You can also do this.

An example in which the detection target is an excitation current will be described below.

Current sensors 14 and 15 are provided to detect the excitation current from the power amplifier 4.5 to the solenoid of each electromagnet 2.3, and the detected current value signals from the current sensors 14.15 are differentially calculated. , are connected to be input to the first storage device 12 via the A/D converter 16.

A second storage device 17 is connected to the first storage device 12, and a steady state discriminator 18 is connected to the second storage device 17, respectively. Further, the second storage device 17 has the first contact point 1
9 and filter 20 from the compensation signal input point (in this case, the input signal is the displacement amount) to the signal detection point (in this case, the detection signal is the current value). It is connected to an inverse transfer function circuit 21 , and the inverse transfer function circuit 21 is connected to the third storage device 13 via a subtracter 22 .

The third storage device 13 is a subtracter (or an adder) so that its output is subtracted and inputted to the reference position signal from the reference signal source of the excitation current to the PID operation unit 7 via the D/A converter 23.
24, and the output side is connected to the adder 22 via the second contact 25, and the first contact 19 and the second contact 25 are the output of the contact drive circuit 26 connected to the steady state discriminator 18. It is connected so that it can be opened and closed by a signal.

In the case of control in which the geometric center line of the rotation axis, that is, the rotation axis line, is made to coincide with the inertial center line, the filter 20 can pass and extract only the rotational angular velocity frequency component of the rotation axis 1.

When moving the geometric center line of the rotating shaft, that is, the rotating axis, so as to absorb vibrations at the resonant frequency of the rotating shaft including the attached rotating body or vibrations at the resonant frequency of the fluid working space in the fluid device, the filter 20 , it is possible to pass through and extract only the resonant frequency components of the rotating shaft including the rotating body and the resonant frequency components of the fluid working space.

Embodiments of the magnetic bearing control method of the present invention will be described in accordance with the operations and effects of the above magnetic bearing control device.

A reference position signal for positioning the rotating shaft 1 at the neutral position, which is a normal state, is transmitted from the reference signal source of the excitation current to the power amplifiers 4 and 5.
The excitation current corresponding to the reference position signal is supplied from the power amplifiers 4 and 5 to the solenoid of the electromagnet 2 and 3, and the magnetic force of the upper and lower electromagnets 2 and 3 acts, and the rotating shaft 1 It is rotatably supported at a position where the geometric center line coincides with the rotational axis, that is, at a neutral position.

The rotation shaft 1 is started to rotate by a drive source (not shown), is accelerated, and then enters a steady rotation state.

The radial position of one point in the axial direction of the rotating shaft 1 during rotation (
(in the illustrated example, the vertical position is representative) is detected by the displacement sensors 8 and 9 as a gap value between the tip and the outer peripheral surface of the rotating shaft 1, and the detection output is input to the sensor signal adjuster 10. The sensor signal adjuster 10 matches the relationship between the unit electric quantity and displacement of the displacement sensor signal with the relationship between the unit electric quantity and displacement of the reference position signal, and furthermore, the shaft position signal from the sensor signal adjuster 10 is adjusted to the reference position. It is fed back to the signal, but the rotation axis 1 is upward from the neutral position.

Or, if it deviates downward, a positive or negative deviation occurs between the reference position signal and the shaft position signal. The deviation is input to the PID operation unit 7, subjected to a reset rate operation, and input to the power amplifier 4.5.

As a result, the excitation currents supplied from the power amplifiers 4 and 5 are controlled so as to generate a magnetic force in the electromagnet 2.3 that makes the above deviation zero.

At that time, the first storage device 12, the second storage device 17, and the third storage device 12,
The storage device 13 is reset and the data (contents) are initialized to zero, and the rotational angular position of the rotating shaft 1 during rotation is determined by the angle scale disk 11 that rotates integrally with the rotating shaft 1 by the angle signal generator 11a. The angle signal θi for each fixed angle is detected by being read and input to the first storage device 12. On the other hand, the excitation currents to the electromagnets 2.3 that vary under control are detected by current sensors 14.15, respectively, and their detected current values 1a.

The current value ■ which is the sum of ib is passed through the A/D converter 16,
The data is input to the first storage device 12.

Therefore, the angle signal θi acts as a gate, and the current value ・■ corresponding to each angle signal θl, that is, the angular position of the rotating shaft 1 (
The current value (θi) for each θi) is stored.

Then, when the rotating shaft 1 makes one rotation, the current value II (θ1) for each angular position (θi) for one rotation is stored, and is transferred to the second storage device 17, and the first storage device 1
The data (contents) of No. 2 are zeroed, and the current value I2 (θi) for each angular position (θl) for one primary rotation is stored in the same manner as above. Then, the angular position for one rotation of the previous one rotation (
Current value r+(θi) for each θi) and current value I2(θ1) for each angular position (θ1) for the next one rotation corresponding to each of them
The difference signal I+(θ1)−iz(θl) is input to the steady state discriminator 18.

In the steady state discriminator 18, the difference signal + (θ1) I
2(θi) is compared and determined with the standard value S, and it is determined whether the rotation of the rotating shaft 1 is in a stable state.

That is, if I2(θi)≦S, the rotation of the rotating shaft 1 is considered to be in a stable state with no acceleration or deceleration.

Therefore, when ■+(θ1)-I2(θi)≦S, an activation signal is input to the contact drive circuit 26, and the contact drive circuit 2
6, the first contact 19 and the second contact 25 are closed.

When the first contact 19 is closed, the data (content) I2 (θi) of the second storage device 17 during one rotation of the rotating shaft 1 (or the data (content) ■, (θi) of the first storage device 1z) ) is input to the filter 20.

Here, first, in the case of control to match the geometric center line of the rotation axis 1, that is, the rotation axis line, with the inertial center line, the filter 2
0, components other than the component θ=ω of the variation of I2(θi) during one rotation of the rotating shaft 1 are removed, and the resultant I3
#I2(ωt) is due to the deviation of the geometric center line of the rotating shaft 1 from the inertial center line, and is input to the inverse transfer function circuit 21.

Then, the inverse transfer function circuit 21 corresponds to the deviation from the geometrical neutral position where the gap between the tip of the displacement sensor 8.9 and the outer peripheral surface of the rotating shaft 1 is uniform. It is converted into a deviation value δ and input into the third storage device 13, and the deviation value δ corresponding to each angle signal θi, that is, the deviation value δ(θi) for each angular position (θi) of the rotating shaft 1 is be remembered.

In other words, the deviation value δ (θl) is the force that supports the centrifugal force generated by the deviation between the geometric center line and the inertial center line at each angular position of the rotating shaft 1 (the eccentric center of gravity distance due to unbalance). This is a compensation value corresponding to the displacement signal input value required to generate the electromagnet.

At this time, the angle signal θi of the rotating shaft 1 during rotation is input to the third storage device 13 in the same manner as described above. Therefore, the angle signal θ
l performs a gate action, and each angular position (θ1) of the rotation axis 1
The deviation value δ(θl) for each is input to the subtracter 24 via the D/A converter z3, and the reference position signal, which is the position where the rotational axis of the rotational shaft 1 coincides with the geometric center line, is determined by the deviation The value δ(θi
), that is, it becomes a corrected reference position signal from which the compensation value is subtracted.

As a result, the correction reference position signal for each angular position (θl) of the rotary shaft 1 input to the PID operation unit 7 is supported at the geometric neutral position where the rotational axis of the rotary shaft 1 coincides with the geometric center line. Since the basic control circuit is operated in such a way that the electromagnetic force of the electromagnet required to support the centrifugal force is separated from the electromagnetic force of the electromagnet necessary for It is controlled so that it is displaced by the deviation value δ (θl) and swings around, but its axis of rotation is controlled so that it coincides with the center line of inertia.

Next, it absorbs vibrations at the resonant frequency of the rotating shaft including the rotating body at the rotating shaft 1 to which the rotating body is attached, and vibrations at the resonant frequency of the fluid working space of the fluid equipment at the rotating shaft 1 which is the rotating axis of the fluid equipment. In this case, the filter 20 removes components other than the resonance frequency component of the fluctuation of I2(θl) during one rotation of the rotating shaft 1, and the result is I:+#Iz
(ωt) is due to the deviation of the geometric center line of the rotation axis 1 from the rotation axis, and is input to the inverse transfer function circuit 21.

Hereafter, the rotating shaft 1 is processed through the same control process as in the above case.
The rotary shaft 1 is rotatably supported with its axis of rotation deviated enough to eliminate the vertical component of vibrational displacement.

In any of the above cases, when the compensation value signal is output from the third storage device I3, the data (content) of the third storage device 13 is held.

However, it is difficult to construct a complete inverse transfer function circuit using current electric circuit elements, and in reality, an approximate circuit is used instead. Therefore, it is difficult to completely align the position of the rotational axis of the rotational shaft 1 with a predetermined position using only the above-mentioned adjustment control for one rotation. Therefore, even after the transient time due to the first compensation operation has passed, there remains a mismatch between the axis of rotation and the center of inertia, and due to this deviation, the deviation value δ corresponding to each angle signal θi is changed in the same way as above. That is, rotation axis 1
The deviation value δ(θi) for each angular position (θi) of is input to the third storage device. The value added by the adder 22 is input as a new compensation value and stored.Then, the same adjustment control of the position of the rotating shaft 1 as described above is performed repeatedly.

By repeating such adjustment control of the position of the rotary shaft 1 many times, the rotational axis of the rotary shaft 1 is adjusted to a predetermined position as much as possible in the vertical direction component.

The illustrated example above shows a magnetic bearing for a pair of electromagnets for vertical control at one location in the axial direction of the rotating shaft 1, so the position adjustment of the rotating axis of the rotating shaft 1 will be explained in terms of the vertical component. However, the magnetic bearing is two-dimensionally equipped with at least two pairs of electromagnets (top, bottom, left, and right) at one location in the axial direction of the rotating shaft 1, and furthermore, electromagnets are provided at at least two locations in the axial direction, allowing for so-called five-axis control. It is easy to understand that by controlling the excitation current of each pair of electromagnets in the same manner as described above, the rotational axis of the rotating shaft 1 is adjusted and controlled so as to coincide with a predetermined position.

In the above embodiment, the compensation signal input point for subtracting and inputting the compensation value (the installation point of the subtracter 24) is installed on the upstream side of the basic control circuit closed loop. appropriate part of, for example, resoPIDID
It may be installed at the excitation current command value region between the operating region and the phase inverter 6. In that case, the content of the inverse transfer function circuit 21 is composed of an inverse transfer function of the basic control circuit closed loop transfer function from the excitation current command to the excitation current.

Furthermore, in the above embodiment, the magnetic force of the electromagnet is detected by detecting the excitation current, but instead of the excitation current, the magnetic flux density in the bearing gap is used, and a detector for the magnetic flux density in the bearing gap, such as a Hall element, is used. etc. are buried in the magnetic pole surface,
Alternatively, the magnetic force of the electromagnet is used, and a force detector such as a load cell is inserted between the structure supporting the electromagnet. Even if the detection signals of the various detectors described above are input to the first storage device 12 and processed, the same operations and effects as in the above embodiment can be obtained.

By providing the filters 20 of the respective filter frequencies in the compensation value conversion circuit in parallel, it is also possible to reduce all the vibrations of the rotating device due to the corresponding causes.

Furthermore, the following embodiments are common to the above-mentioned embodiments.

A specific frequency cutoff filter is used instead of the specific frequency pass filter as described above, and the subtracter 24 that subtracts and inputs the output of the third storage device 13 from the reference position signal is replaced with an adder 24 that adds and inputs the output. It is. Even in this case, the same effect as in each of the above embodiments is applied to the rotating shaft 1.

[Effects of the Invention] According to the control of the magnetic bearing of the present invention, the rotating shaft is controlled so as to eliminate vibrations of the rotating shaft due to unbalance of the rotating body, resonance frequency of the rotating body, resonance frequency of the fluid working space in fluid equipment, etc. In the technology for controlling magnetic bearings for support, it is possible to control magnetic bearings with high precision without requiring a high-precision analog calculation circuit and without causing errors due to voltage fluctuations or temperature fluctuations. Moreover, the device is cheaper and more practical than conventional control devices.

[Brief explanation of the drawing]

The drawing is a schematic configuration diagram of a magnetic bearing control device in an embodiment of the present invention.

Claims (6)

[Claims] (1) In a magnetic bearing that controls the excitation current based on a reference position signal that aligns the geometric center line of the outer peripheral surface corresponding to the electromagnet of the rotating shaft to which the rotating body is attached with the rotational axis, the rotational angular position of the rotating shaft and Detects the excitation current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet, extracts only the specific frequency component of the fluctuation component of the excitation current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet, and detects the excitation current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet. Compensation for the frequency component in the magnetic flux density of the electromagnet or the fluctuation component of the electromagnetic force of the electromagnet Inverse transfer of the closed loop transfer function from the signal input point to the detection signal detection point of the exciting current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet A magnetic bearing control method that calculates through a function circuit, synchronizes its output with the rotation angle position, and subtracts it into the compensation signal input point to control the excitation current. (2) An electromagnet provided facing the outer peripheral surface of the rotating shaft to which the rotating body is attached, and a first magnet that detects the rotational angular position of the rotating shaft.
a second detector that detects the exciting current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet; and a second detector that detects the exciting current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet; A filter that extracts only a specific frequency component in the fluctuation component of the magnetic flux density or the electromagnetic force of the electromagnet, and the excitation current that is the output of the filter, the magnetic flux density of the bearing gap, or the frequency component in the fluctuation component of the electromagnetic force of the electromagnet. A reverse transfer function circuit of a closed loop transfer function from the compensation signal input point to the detection signal detection point of the excitation current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet, and the excitation current of the electromagnet is controlled. a control circuit that aligns the geometric center line of the outer peripheral surface of the rotating shaft corresponding to the electromagnet with the rotation axis; and a control circuit that aligns the geometric center line of the outer peripheral surface of the rotating shaft corresponding to the electromagnet with the rotation axis, Subtraction in which the compensation value output from the inverse transfer function circuit is subtracted and input at a compensation signal input point provided at an arbitrary point in the signal path from the input point of the reference position signal to the excitation current command value input point. A magnetic bearing control device consisting of a (3) In a magnetic bearing that controls the excitation current based on a reference position signal that aligns the geometric center line of the outer circumferential surface corresponding to the electromagnet of the rotating shaft to which the rotating body is attached with the rotational axis, the rotational angular position of the rotating shaft and Detects the excitation current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet, and removes only the specific frequency component of the fluctuation component of the excitation current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet. Compensate the magnetic flux density of the gap, or the fluctuation component of the electromagnetic force of the electromagnet with the frequency component removed, from the signal input point to the excitation current, the magnetic flux density of the bearing gap,
Or a magnetic bearing that calculates the electromagnetic force of an electromagnetic force through an inverse transfer function circuit of the closed loop transfer function up to the detection point, synchronizes the output with the rotation angle position, and controls the excitation current by adding and inputting it to the compensation signal input point. control method (4) An electromagnet provided opposite to the outer peripheral surface of the rotating shaft to which the rotating body is attached, and a first magnet for detecting the rotational angular position of the rotating shaft.
a second detector that detects the exciting current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet; and a second detector that detects the exciting current, the magnetic flux density of the bearing gap, or the electromagnetic force of the electromagnet; A filter that removes only a specific frequency component in the fluctuation component of the magnetic flux density or the electromagnetic force of an electromagnet, and the excitation current that is the output of the filter, the magnetic flux density of the bearing gap, or the fluctuation that removes the frequency component of the electromagnetic force of the electromagnet. An inverse transfer function circuit of a closed loop transfer function from a compensation signal input point that obtains a compensation value from a component to a detection signal detection point of an excitation current, a magnetic flux density in a bearing gap, or an electromagnet's electromagnetic force, and controls the excitation current of the electromagnet. a control circuit that aligns the geometric center line of the outer peripheral surface of the rotating shaft corresponding to the electromagnet with the rotation axis; and a control circuit that aligns the geometric center line of the outer peripheral surface of the rotating shaft corresponding to the electromagnet with the rotation axis, Addition of the compensation value output from the inverse transfer function circuit at a compensation signal input point provided at any point in the signal path from the input point of the reference position signal to the input point of the excitation current command value. A magnetic bearing control device consisting of a (5) When the specific frequency is a rotational angular velocity frequency component of a rotating shaft, a resonant frequency component of a rotating shaft including a rotating body, a resonant frequency component of a fluid working space when the specific frequency is a rotating shaft of a fluid device, or an appropriate combination thereof in parallel. A method for controlling a magnetic bearing according to claim (1) or (3), which is a combination. (6) When the specific frequency is a rotational angular velocity frequency component of a rotating shaft, a resonant frequency component of a rotating shaft including a rotating body, or a resonant frequency component of a fluid working space when the specific frequency is a rotating shaft of a fluid device, or an appropriate combination thereof in parallel. The magnetic bearing control device according to claim (2) or (4), which is a combination.