JP2000205261A - Magnetic bearing device for storage of electric power - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent touch-down or the like by suppressing run-out of a rotor caused by an earthquake. SOLUTION: At a certain spacing, seismic wave sensors Z1-Z8 are installed radially around the device body S with which a control device 30 is connected. The control device 30 alters the control characteristics on the basis of the input signals given by the sensors Z1-Z8 to prevent touch-down or the like by suppressing the rotor resonance with the seismic waves.

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 for storing electric power, for example, converting surplus electric power into kinetic energy of a flywheel and storing it.

[0002]

2. Description of the Related Art As a conventional magnetic bearing device for power storage,
A rotating body having a flywheel, an electric motor including a rotor concentrically arranged with the rotating body and a stator arranged on the outer periphery of the rotor, a superconducting bearing for supporting the rotating body in a non-contact manner, An electric power storage comprising a magnetic bearing for non-contact support, a control device for controlling the magnetic bearing, and means for converting kinetic energy stored in the flywheel into electric energy and supplying the electric energy to the control device when the operation of the motor is stopped. A magnetic bearing device has been proposed (JP-A-6-129427). In this magnetic bearing device for storing electric power, when resonance occurs in the rotating body after the rotation of the rotating body is started, displacement of the rotating body is detected, and the excitation current is applied to the corresponding electromagnet of the magnetic bearing by a command signal of the control device. Is supplied. Thereby, the shake of the rotating body is corrected, and the touch-down is prevented. Also, when the operation of the motor is stopped,
It has a means to convert the kinetic energy stored in the flywheel to electric energy, so it is possible to supply power to the control device for a certain period of time even during a power failure, and it is generated until the rotating body stops. Is corrected.

[0003]

When the size of an axial magnetic bearing and a radial magnetic bearing becomes large, the natural frequency of the magnetic bearing becomes several Hz, and the seismic wave contains a frequency component of 1 to several Hz. The possibility that the component and the magnetic bearing resonate is very high. In the electric power storage magnetic bearing device, even if the vibration occurs due to the earthquake, the vibration generated in the rotating body is corrected to a certain limit, thereby preventing the touchdown or the like. However, if the frequency component of the seismic wave contains the same natural frequency as the natural frequency of the magnetic bearing at a high level, the limit of vibration correction is exceeded, and there is a risk of touchdown. When the touchdown occurs, the rotation speed of the rotating body rapidly decreases, and the kinetic energy stored in the flywheel is consumed as thermal energy of friction. The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a magnetic bearing device for power storage that can suppress a swing of a rotating body due to an earthquake when an earthquake occurs and can prevent a touchdown or the like. Aim.

[0004]

According to the present invention, there is provided a magnetic bearing device for electric power storage according to the present invention, wherein a rotating body having a flywheel is supported in a non-contact manner by a magnetic supporting means including an electromagnet, and the rotating body has In a power storage magnetic bearing device for detecting a displacement of a body and performing electromagnet control based on the displacement by a control device, a seismic wave detection sensor is disposed at a plurality of positions separated by a predetermined distance from the rotating body, and the control device Receives the output of the seismic wave detection sensor, changes the control characteristics of the electromagnet control, and changes the support force of the magnetic support means (claim 1).
According to this power storage magnetic bearing device, since the control characteristics of the electromagnet control for correcting the vibration of the rotating body are changed based on the information from the seismic wave detection sensor, it is possible to suppress the resonance between the seismic wave and the rotating body. it can.

According to a first aspect of the present invention, when the output level of the seismic wave detection sensor exceeds a predetermined value, the control device increases at least one of a steady current and a feedback gain. Preferably (claim 2), in this case, the support force of the magnetic support means can be easily improved.

[0006]

Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is a schematic view showing a magnetic bearing device for power storage according to an embodiment of the present invention, and FIG. 2 is a plan view thereof. The control device 30 is connected to the device main body S. P wave sensors Z1 to Z as radial seismic wave detection sensors are arranged around the control device 30 radially.
8 are buried and connected to the control device 30 respectively. The P-wave sensors Z1 to Z8 detect the acceleration of the P-wave when an earthquake having an epicenter of E occurs, and output the detected acceleration to the control device 30. In each of the P-wave sensors Z1 to Z8, the distance L between each of the P-wave sensors Z1 to Z8 and the control device 30 is calculated by the following equation: L> v · tv: the propagation speed of the P wave t: It is located at a position that satisfies the processing time required to change the control characteristics and improve the bearing support force.

FIG. 3 is a sectional view showing an apparatus main body S of the magnetic bearing apparatus for power storage according to one embodiment of the present invention.
FIG. 2 is a block diagram showing a partial configuration and a configuration of a control device. The apparatus main body S includes a vertically rotating body 1, a superconducting magnetic bearing 2, an axial displacement sensor 3a, a pair of upper and lower radial displacement detecting units 3r, and an axial magnetic bearing 5.
a, a pair of upper and lower radial magnetic bearings 5r, an electric motor 9 including a rotor 9a attached to the rotating body 1 and a stator 9b disposed on the outer peripheral side thereof, and a pair of upper and lower flywheels 1
3, a pair of upper and lower or a plurality of pairs of touchdown bearings 27, which are arranged inside the cylindrical upper housing 10, the intermediate housing 11, and the lower housing 12.

The superconducting magnetic bearing 2 supports the rotating body 1 in a non-contact manner in the axial and radial directions, the radial magnetic bearing 5r supports the rotating body 1 in a non-contacting manner in the radial direction, and the axial magnetic bearing 5a supports the rotating body 1 on the shaft. Non-contact support in the direction. The radial displacement detection unit 3r detects the displacement of the rotating body 1 in the radial direction, and the axial displacement sensor 3a detects the displacement of the rotating body 1 in the axial direction, and outputs the detected displacement to the control device 30. The electric motor 9 rotates the rotating body 1, the flywheel 13 converts the surplus power into rotational kinetic energy and stores it, and the touchdown bearing 27 supports the rotating body 1 in an emergency.

The axial magnetic bearing 5a and the radial magnetic bearing 5r have a plurality of electromagnets. The superconducting magnetic bearing 2 includes a permanent magnet 15 that is arranged concentrically with the rotating body 1.
And a superconductor section 16 disposed opposite to the superconductor section. The permanent magnet section 15 includes a support disk 17 and an annular permanent magnet 18 fixed to the outer periphery of the support disk 17 via a ferromagnetic material 19. The superconductor section 16 includes a superconductor housing member 21 and a superconductor 22 housed in the hollow portion 21a. The superconductor accommodating member 21 is connected to a refrigerant accommodating container (not shown) via a refrigerant supply pipe 23 and a refrigerant discharge pipe 24.

In the block diagram of FIG. 4, the displacement detecting section 3 of the apparatus main body S is the above-described radial displacement detecting unit 3r and the axial displacement sensor 3a, and the magnetic bearing section 5 is a radial magnetic bearing 5r and an axial magnetic bearing 5a. . The control device 30 includes a displacement calculation circuit 31, a magnetic bearing drive circuit 32, an inverter 33, a DSP (digital signal processing device) 35, and an A / D converter 37. The magnetic bearing drive circuit 32 includes a plurality of power amplifiers corresponding to each electromagnet of the magnetic bearing 5. The inverter 33 has a DS
The rotation of the electric motor 9 is controlled based on the signal from P35. The seismic wave detector 36 includes the above-described P-wave sensors Z1 to Z8. Each of the P-wave sensors Z1 to Z8 detects the acceleration of the P-wave, and outputs the acceleration to the DSP 35 via the A / D converter 37.

In the magnetic bearing device for power storage constructed as described above, first, the radial magnetic bearing 5r and the axial magnetic bearing 5a are put into an operating state, and the rotating body 1 is supported in a non-contact manner in the axial direction and the radial direction. To a predetermined operating position. Next, the superconductor section 16 is brought close to the predetermined position with respect to the permanent magnet section 15, and the superconductor 22 is cooled to maintain the second type superconducting state. At this time, the magnetic flux emitted from the permanent magnet 18 and entering the superconductor 22 is pinned to a pinning point of the superconductor 22 by a pinning effect. Further, the superconductor section 16 is raised, and when the support burden force by the axial magnetic bearing 5a becomes zero, the superconductor section 16 is stopped at that position. Thus, the weight of the rotating body 1 is supported only by the superconducting magnetic bearing 2.
Then, the motor 9 is driven to rotate the rotating body 1 at high speed.

When a displacement occurs in the rotation of the rotating body 1, the displacement is corrected by the magnetic bearing 5. The position control (electromagnet control) of the rotating body 1 is executed as follows.
The displacement calculation circuit 31 calculates the displacement of the rotating body 1 based on the input signal from the displacement detection unit 3 and outputs a displacement signal corresponding to these displacements to the DSP 35. The DSP 35 outputs a current command signal to each of the electromagnets of the magnetic bearing unit 5 to the magnetic bearing unit drive circuit 32 based on the predetermined sampling time. The magnetic bearing drive circuit 32 supplies an exciting current to the corresponding electromagnet of the magnetic bearing 5 based on the current command signal. Thereby, the displacement of the rotating body 1 is corrected, and the rotating body 1 is supported at the target position in a non-contact manner.

When an earthquake occurs near the magnetic bearing device for power storage according to this embodiment, the P-wave vibration of the earthquake is captured by the seismic wave detector 36 and the output is sent to the A / D converter 37. When the output level of the A / D converter 37 exceeds a predetermined value, the DSP 35 changes the control characteristics of the position control of the rotating body 1 described above. FIG. 5 is a flowchart illustrating an example of a control characteristic changing process performed by the DSP 35. This process is executed at a high speed every predetermined sampling time. First, in step S1, DS
P35 reads the voltage value P output from the A / D converter 37 based on the input signals from the P-wave sensors Z1 to Z8. Then, it is determined whether or not the control characteristics of the position control of the rotating body 1 have already been changed (step S2).

If the control characteristics have not been changed, D
SP35 compares the output voltage value P from each P-wave sensor with threshold value PP, and determines whether the output voltage value P from at least one P-wave sensor is greater than threshold value PP (step S3). . When an output voltage value P from at least one P-wave sensor is larger than a threshold value PP, the DSP
35 changes the control characteristics (step S4). Specifically, it outputs a current command signal to the magnetic bearing unit drive circuit 32,
The steady current of the corresponding electromagnet of the magnetic bearing unit 5 is increased. Further, the responsiveness of the position control of the rotating body 1 is increased by increasing the feedback gain. Thereby, the supporting force of the magnetic bearing 5 is improved, and the natural frequency of the magnetic bearing 5 in the axial direction and the radial direction is increased.

On the other hand, if all the output voltage values P are equal to or smaller than the threshold value PP in step S3, the process is terminated. If it is determined in step S2 that the control characteristics have already been changed, the DSP 35 determines whether all the output voltage values P are equal to or less than the threshold value PP (step S5). All output voltage values P are equal to threshold value PP
In the following cases, the DSP 35 restores the control characteristics (Step S6). Specifically, the steady current is reduced,
Decrease the feedback gain. Thereby, the natural frequency of the magnetic bearing portion 5 decreases. In step S5, when at least one output voltage value P is larger than the threshold value PP, the changed control characteristics are maintained.

As described above, when the control characteristic of the position control of the rotating body 1 is changed, the supporting force of the magnetic bearing 5 is improved, the natural frequency of the magnetic bearing 5 is increased, and the frequency component of the seismic wave is increased. Deviate. Therefore, resonance between the seismic wave and the rotating body 1 is suppressed. Since the resonance is suppressed, the rotating body 1 is supported in a non-contact manner at the target position even when the seismic wave reaches the apparatus main body S. Therefore, touchdown and the like are prevented, and loss of the kinetic energy stored in the flywheel 13 is prevented.

In the above embodiment, the case where both the steady-state current and the feedback gain are changed has been described. However, at least one of the steady-state current and the feedback gain may be changed. However, it is preferable to change both. Although only one threshold value PP is provided, a plurality of threshold values PP are provided in a stepwise manner.
The control characteristics may be finely changed for each threshold value PP. Further, in the above-described embodiment, the case where the acceleration detection type P wave sensor is applied as the seismic wave detection sensor has been described.
A wave sensor may be used. However, a type that detects so-called absolute acceleration or absolute speed is preferable. Further, another seismic wave detection sensor may be used.

[0018]

As described above, according to the magnetic bearing device for power storage according to the first aspect, the seismic wave detection sensors are disposed at a plurality of positions separated from the rotating body by a predetermined distance, and the seismic wave detection sensors Since the control characteristics of the electromagnet control for correcting the shake of the rotating body are changed based on the information, the resonance between the seismic wave and the rotating body can be suppressed. Therefore, touchdown and the like are prevented, and loss of kinetic energy stored in the flywheel is prevented.

According to the magnetic bearing device for power storage according to the second aspect, the control device increases at least one of the steady-state current and the feedback gain when the output level of the seismic wave detection sensor exceeds a predetermined value. Thus, the supporting force of the magnetic supporting means can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a magnetic bearing device for power storage according to an embodiment of the present invention.

FIG. 2 is a plan view showing a power storage magnetic bearing device according to an embodiment of the present invention.

FIG. 3 is a sectional view showing a device main body S of the magnetic bearing device for power storage according to one embodiment of the present invention.

FIG. 4 is a block diagram showing a partial configuration of a device main body S and a configuration of a control device.

FIG. 5 is a flowchart showing a control characteristic change executed by the DSP.

[Explanation of symbols]

 S Device main body Z1 to Z8 P wave sensor 1 Rotating body 3 Displacement detecting unit 5 Magnetic bearing unit 9 Motor 30 Control device 31 Displacement calculation circuit 32 Magnetic bearing drive circuit 35 DSP 37 A / D converter

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 3J102 AA01 BA03 BA19 CA02 CA14 DA02 DA03 DA09 DA22 DB05 DB10 DB11 DB18 DB22 DB32 GA09

Claims (2)

[Claims] 1. A rotating body having a flywheel is supported in a non-contact manner by magnetic supporting means including an electromagnet.
In a power storage magnetic bearing device that detects a displacement of the rotating body and performs electromagnet control based on the displacement by a control device, a seismic wave detection sensor is disposed at a plurality of positions separated by a predetermined distance from the rotating body, A magnetic bearing device for electric power storage, wherein a control device receives an output of the seismic wave detection sensor, changes a control characteristic of the electromagnet control, and changes a support force of the magnetic support means. 2. The magnetic bearing device according to claim 1, wherein the controller increases at least one of a steady current and a feedback gain when an output level of the seismic wave detection sensor exceeds a predetermined value.