JP3937623B2 - Magnetic bearing device for power storage - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic bearing device for power storage that stores, for example, surplus power by converting it into kinetic energy of a flywheel.
[0002]
[Prior art]
As a conventional magnetic bearing device for electric power storage, a rotating body having a flywheel, a motor arranged concentrically with the rotating body, and an electric motor comprising a stator arranged on the outer periphery of the rotor, and the rotating body are supported in a non-contact manner. A superconducting bearing, a magnetic bearing that supports the rotating body in a noncontact manner, a control device that controls the magnetic bearing, and a control device that converts the kinetic energy stored in the flywheel into electrical energy when the motor is stopped. There has been proposed a magnetic bearing device for electric power storage provided with a means for supplying to a power source (Japanese Patent Laid-Open No. 6-129427).
In this power storage magnetic bearing device, when resonance occurs in the rotating body after the rotating body starts rotating, the displacement of the rotating body is detected, and an excitation current is applied to the corresponding electromagnet of the magnetic bearing by a command signal from the control device. Is supplied. This corrects the shake of the rotating body and prevents touchdown. In addition, since it has means to convert kinetic energy stored in the flywheel into electrical energy when the motor is stopped, it can supply power to the control device for a certain amount of time even during a power outage. The shake that occurs until the motor stops is corrected.
[0003]
[Problems to be solved by the invention]
By the way, when both an axial magnetic bearing and a radial magnetic bearing become large, the natural frequency becomes several Hz, and the seismic wave includes a frequency component of 1 to several Hz, so this component and the magnetic bearing can resonate. The nature is very high. In the magnetic bearing device for power storage, even if vibration is caused by an earthquake, the vibration generated in the rotating body is corrected up to a certain limit to prevent touchdown or the like.
However, if the frequency component of the seismic wave contains the same frequency as the natural frequency of the magnetic bearing at a high level, the vibration correction limit may be exceeded and touchdown may occur. When touched down, the rotational speed of the rotating body decreases rapidly, and the kinetic energy stored in the flywheel is consumed as thermal energy for friction.
The present invention has been made in view of such circumstances, and it is intended to provide a magnetic bearing device for power storage that can suppress the shake of a rotating body due to an earthquake and prevent touchdown or the like when an earthquake occurs. Objective.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, a magnetic bearing device for power storage according to the present invention supports a rotary body having a flywheel in a non-contact manner by a magnetic support means including an electromagnet, and detects a displacement of the rotary body to control the rotary body. In the magnetic bearing device for power storage that can perform electromagnet control based on the displacement by
At a plurality of positions separated by a predetermined distance from the rotating body and the distance L to the control device is L> v · t (where v is the propagation speed of the P wave of the seismic wave, and t is calculated by the control device. The seismic wave detection sensor is disposed at a position that satisfies the processing time required for processing and changing the control characteristics of the electromagnet control to change the supporting force of the magnetic support means,
When the control device receives at least one output of the plurality of seismic wave detection sensors and an output level thereof exceeds a predetermined value, the control device increases at least one of a steady current and a feedback gain, thereby controlling the electromagnet control characteristics. And changing the supporting force of the magnetic support means to change the natural frequency in the axial direction and the radial direction in the magnetic support means in order to suppress the resonance between the seismic wave and the rotating body. (Claim 1).
According to this magnetic bearing device for power storage, since the control characteristics of the electromagnet control for correcting the shake of the rotating body are changed based on the information from the seismic wave detection sensor, the resonance between the seismic wave and the rotating body can be suppressed. it can.
[0005]
2. The magnetic bearing device for power storage according to claim 1, wherein the control device increases at least one of a steady current and a feedback gain when at least one output level of the plurality of seismic wave detection sensors exceeds a predetermined value. In this case, the support force of the magnetic support means can be easily improved.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described 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. A control device 30 is connected to the device body S. P-wave sensors Z <b> 1 to Z <b> 8 as seismic wave detection sensors are embedded radially around the control device 30 and are connected to the control device 30, respectively.
P-wave sensors Z <b> 1 to Z <b> 8 detect the acceleration of the P-wave and output it to control device 30 when an earthquake with E as the epicenter occurs. Each of the P wave sensors Z1 to Z8 has a distance L between each of the P wave sensors Z1 to Z8 and the control device 30 such that the following formula L> v · t
v: Propagation speed of P wave t: Arranged at a position that satisfies the processing time required for the control device 30 to perform arithmetic processing and change the control characteristics to improve the bearing support force.
[0007]
FIG. 3 is a cross-sectional view showing the device main body S of the magnetic bearing device for power storage according to one embodiment of the present invention, and FIG. 4 is a block diagram showing a part of the configuration and the configuration of the control device.
The apparatus main body S includes a vertical axis rotating body 1, a superconducting magnetic bearing 2, an axial displacement sensor 3a, a pair of upper and lower radial displacement detection units 3r, an axial magnetic bearing 5a, a pair of upper and lower radial magnetic bearings 5r, and a rotating body 1. The motor 9 is composed of an attached rotor 9a and a stator 9b disposed on the outer periphery thereof, a pair of upper and lower flywheels 13, and a pair of upper and lower touchdown bearings 27, and these are a cylindrical upper housing. 10, disposed in the middle housing 11 and the lower housing 12.
[0008]
The superconducting magnetic bearing 2 supports the rotating body 1 in a non-contact manner in the axial direction and the radial direction, the radial magnetic bearing 5r supports the rotating body 1 in a non-contact manner in the radial direction, and the axial magnetic bearing 5a does not support the rotating body 1 in the axial direction. Support contact. The radial displacement detection unit 3r detects the radial displacement of the rotating body 1, and the axial displacement sensor 3a detects the axial displacement of the rotating body 1 and outputs the detected displacement to the control device 30. The electric motor 9 rotates the rotating body 1, the flywheel 13 converts surplus electric power into rotational kinetic energy and stores it, and the touchdown bearing 27 supports the rotating body 1 in an emergency.
[0009]
The axial magnetic bearing 5a and the radial magnetic bearing 5r include a plurality of electromagnets.
The superconducting magnetic bearing 2 includes a permanent magnet portion 15 disposed concentrically with the rotating body 1 and a superconductor portion 16 disposed opposite to the permanent magnet portion 15. The permanent magnet portion 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 body 19. The superconductor portion 16 includes a superconductor accommodating member 21 and a superconductor 22 accommodated in the hollow portion 21a. The superconductor housing member 21 is connected to a refrigerant housing container (not shown) via a refrigerant supply pipe 23 and a refrigerant discharge pipe 24.
[0010]
In the block diagram of FIG. 4, the displacement detection unit 3 of the apparatus main body S is the radial displacement detection unit 3r and the axial displacement sensor 3a described above, and the magnetic bearing unit 5 is the radial magnetic bearing 5r and the 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 unit drive circuit 32 includes a plurality of power amplifiers corresponding to the electromagnets of the magnetic bearing unit 5.
The inverter 33 controls the rotation of the electric motor 9 based on the signal from the DSP 35.
The seismic wave detection unit 36 includes the P wave sensors Z1 to Z8 described above. Each of the P wave sensors Z1 to Z8 detects the acceleration of the P wave and outputs it to the DSP 35 via the A / D converter 37.
[0011]
In the magnetic bearing device for power storage configured 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. Ascend to the driving position. Next, the superconductor portion 16 is brought close to a predetermined position with respect to the permanent magnet portion 15, and the superconductor 22 is cooled and held in 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 the pinning point of the superconductor 22 by the pinning effect. Further, the superconductor portion 16 is lifted and stopped at that position when the supporting load by the axial magnetic bearing 5a becomes zero. As a result, the weight of the rotating body 1 is supported only by the superconducting magnetic bearing 2. And the electric motor 9 is driven and the rotary body 1 is rotated at high speed.
[0012]
When displacement occurs in the rotation of the rotating body 1, this displacement is corrected by the magnetic bearing portion 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 detector 3 and outputs a displacement signal corresponding to these displacements to the DSP 35. The DSP 35 outputs a current command signal for each electromagnet of the magnetic bearing unit 5 to the magnetic bearing unit drive circuit 32 based on this at every predetermined sampling time. The magnetic bearing portion drive circuit 32 supplies an excitation current to the corresponding electromagnet of the magnetic bearing portion 5 based on this current command signal. As a result, the displacement of the rotating body 1 is corrected and the rotating body 1 is supported in a non-contact manner at the target position.
[0013]
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 detection unit 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 showing an example of the control characteristic changing process executed by the DSP 35. This process is executed at high speed every predetermined sampling time.
First, in step S1, the DSP 35 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. And it is judged whether the control characteristic of the position control of the rotary body 1 has already been changed (step S2).
[0014]
If the control characteristics have not been changed, the DSP 35 compares the output voltage value P from each P-wave sensor with the threshold value PP, and the output voltage value P from at least one P-wave sensor is equal to the threshold value PP. It is determined whether it is larger (step S3).
When the output voltage value P from at least one P-wave sensor is larger than the threshold value PP, the DSP 35 changes the control characteristics (step S4). Specifically, a current command signal is output to the magnetic bearing unit drive circuit 32 to increase the steady current of the corresponding electromagnet of the magnetic bearing unit 5. Further, the feedback gain is increased to improve the responsiveness of the position control of the rotating body 1. Thereby, the supporting force of the magnetic bearing part 5 improves, and the natural frequency in the axial direction and radial direction of the magnetic bearing part 5 increases.
[0015]
On the other hand, if any output voltage value P is less than or equal to the threshold value PP in step S3, the process ends.
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).
If all the output voltage values P are less than or equal to the threshold value PP, the DSP 35 restores the control characteristics (step S6). Specifically, the steady current is decreased and the feedback gain is decreased. As a result, the natural frequency of the magnetic bearing portion 5 is reduced.
In step S5, when at least one output voltage value P is larger than the threshold value PP, the changed control characteristic is maintained.
[0016]
As described above, when the control characteristics of the position control of the rotating body 1 are changed, the support force by the magnetic bearing portion 5 is improved, the natural frequency of the magnetic bearing portion 5 is increased, and the frequency component of the seismic wave is deviated. Therefore, resonance between the seismic wave and the rotating body 1 is suppressed. By suppressing the resonance, 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. Accordingly, touchdown or the like is prevented, and loss of kinetic energy stored in the flywheel 13 is prevented.
[0017]
In the embodiment, the case where both the steady current and the feedback gain are changed has been described. However, at least one of the steady 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 may be provided in stages, and the control characteristics may be finely changed for each threshold value PP.
In the above embodiment, the acceleration detection type P wave sensor is applied as the seismic wave detection sensor. However, a velocity detection type P wave sensor may be used. However, a type that detects so-called absolute acceleration or absolute velocity is preferable. Other seismic wave detection sensors may be used.
[0018]
【The invention's effect】
As described above, according to the magnetic bearing device for power storage according to claim 1, the seismic wave detection sensors are arranged at a plurality of positions separated by a predetermined distance from the rotating body, and based on the information from the seismic wave detection sensor, Since the control characteristic of the electromagnet control for correcting the shake of the rotating body is changed, resonance between the seismic wave and the rotating body can be suppressed. Accordingly, touchdown or the like is prevented, and loss of kinetic energy stored in the flywheel is prevented.
[0019]
According to the magnetic bearing device for power storage according to claim 2, when the output level of the seismic wave detection sensor exceeds a predetermined value, the control device increases at least one of the steady current and the feedback gain. The support force of the support 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 magnetic bearing device for power storage according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view showing an apparatus main body S of a power storage magnetic bearing device according to an embodiment of the present invention.
FIG. 4 is a block diagram showing a partial configuration of the apparatus main body S and a configuration of a control device.
FIG. 5 is a flowchart showing control characteristic change executed by the DSP;
[Explanation of symbols]
S Device body Z1 to Z8 P wave sensor 1 Rotating body 3 Displacement detector 5 Magnetic bearing 9 Motor 30 Controller 31 Displacement calculation circuit 32 Magnetic bearing drive circuit 35 DSP
37 A / D converter

Claims (1)

Non-contact support of a rotating body having a flywheel by magnetic support means including an electromagnet, and a magnetic bearing for power storage capable of detecting the displacement of the rotating body and performing electromagnet control based on the displacement by a control device In the device
At a plurality of positions separated by a predetermined distance from the rotating body and the distance L to the control device is L> v · t (where v is the propagation speed of the P wave of the seismic wave, and t is calculated by the control device. The seismic wave detection sensor is disposed at a position that satisfies the processing time required for processing and changing the control characteristics of the electromagnet control to change the supporting force of the magnetic support means,
When the control device receives at least one output of the plurality of seismic wave detection sensors and an output level thereof exceeds a predetermined value, the control device increases at least one of a steady current and a feedback gain, thereby controlling the electromagnet control characteristics. And changing the supporting force of the magnetic support means to change the natural frequency in the axial direction and the radial direction in the magnetic support means in order to suppress the resonance between the seismic wave and the rotating body. A magnetic bearing device for power storage.

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