JP5504532B2 - High speed rotating device - Google Patents

Description

  The present invention relates to a high-speed rotating device including a non-contact bearing device that stably supports a rotor (rotating body) in the fields of power equipment such as a flywheel power storage device and a high-speed turbine, and a high-speed rotating machine.

  Currently, data centers, hospitals, railways, and communications are severely damaged if there is an instantaneous voltage drop or power outage. Therefore, a non-contact bearing device using a superconducting bearing is used as a power storage flywheel and a precision device bearing device that does not affect the device and the power system.

  The superconductor has a Meissner effect and a pinning effect below the critical temperature. The Meissner effect refers to the complete diamagnetism exhibited by the superconductor, and the pinning effect refers to the force that fixes the magnetic field in the superconductor. A superconducting bearing device has been developed that holds a rotating main shaft in a non-contact manner by making a superconductor having these two effects and a permanent magnet face each other. As a result, when the levitation body deviates from the equilibrium state, the restoring force works to return to the original position because the magnetic field lines are pinned. Thus, the non-contact levitation apparatus using superconductivity can realize a non-contact levitation apparatus that has a simple structure and is inexpensive.

  However, when the rotating main shaft is rotated, the radial rigidity of the superconducting bearing is small, so that the rotating main shaft shakes greatly due to unbalance of the rotating main shaft or external disturbance such as a motor. Therefore, in order to increase the radial rigidity of the superconducting bearing, a superconducting bearing device having a radial bearing composed of a superconductor and a permanent magnet in the radial direction has been proposed.

  FIG. 12 is a diagram for explaining a conventional technique proposed so as to increase the radial rigidity of the radial bearing as described above (see Patent Document 1). In the illustrated superconducting bearing device, first permanent magnets are attached to both ends of the rotating main shaft in the axial direction. A first superconductor is attached to each housing so as to face the attached first permanent magnet. A motor rotor is attached to the outer diameter side surface of the rotating main shaft, and a motor stator is attached to the inner surface of the housing so as to face the motor rotor. Further, in the illustrated superconducting bearing device, a cylindrical second permanent magnet is attached to the shaft end of the rotating main shaft. A block-shaped second superconductor is attached to the housing so that these second permanent magnets are opposed to each other, with the orientation direction and the radial direction of the rotating spindle aligned.

  Thus, by cooling the superconductor to a critical temperature or lower using a refrigerant or the like, the rotating main shaft is held in a non-contact manner due to the Meissner effect and the pinning effect of the superconductor. Furthermore, by driving the motor stator attached to the housing, the motor rotor attached to the rotating spindle is driven to rotate, so that the rotating spindle can be rotated. Furthermore, this superconducting bearing device has a radial rigidity of a radial bearing formed by a superconductor and a permanent magnet by matching the orientation direction of the superconductor with the radial direction at both ends of the upper and lower shafts of the rotating main shaft. And can prevent the rotating member from swinging in the radial direction.

  However, in such a superconducting bearing device, it is necessary to achieve alignment between the orientation direction of the superconductor and the radial direction at each of the upper and lower shaft ends of the rotating main shaft. It is difficult to make the centers coincide with each other, and energy loss occurs due to the shift of the center of rotation.

  In order to solve the problem of energy loss due to different rotation centers of a plurality of bearings used in combination with a conventional superconducting bearing device, Patent Document 2 discloses that one lower end of a rotating main shaft is connected to one superconducting shaft. A non-contact bearing device supported by a bearing is disclosed. However, the non-contact bearing device disclosed in Patent Document 2 also requires a permanent magnet bearing that supports the upper end of the rotating spindle in the radial direction. FIG. 13 is a diagram showing the non-contact bearing device disclosed in Patent Document 2, and FIG. 14 is a conceptual diagram for explaining the operation of each bearing device shown in FIG. The illustrated non-contact bearing device includes a generator motor including a motor rotor fixed to a rotating main shaft and a motor stator attached to the housing side, and a flywheel fixed to the rotating main shaft. Such a rotating main shaft is attached with a levitation permanent magnet magnetic bearing device that supports the rotating main shaft in the axial direction at the lower end of the rotating main shaft in the axial direction. Furthermore, a superconducting bearing device for positioning is provided at the lower end of the rotating main shaft to support the lower end portion of the rotating main shaft in the radial direction. The superconducting bearing device for positioning is composed of a permanent magnet fixed to the outer peripheral surface of the lower end of the rotating main shaft and a superconductor attached to the housing so as to oppose it, and stabilizes in the radial direction and the axial direction. A permanent magnet repulsive magnetic bearing for positioning attached to the upper end of the rotating spindle includes a permanent magnet fixed to the outer peripheral surface of the upper end of the rotating spindle and another permanent magnet attached to the housing so as to face the permanent magnet. Consists of

  With such a configuration, by driving the motor stator attached to the housing, the motor rotor attached to the rotating spindle is driven to rotate, so that the rotating spindle can be rotated normally. At this time, by cooling the superconductor to a critical temperature or lower using a refrigerant or the like, the rotating main shaft is held in a non-contact manner due to the Meissner effect and the pinning effect of the superconductor. In this way, the illustrated non-contact bearing device has only one superconducting bearing disposed at the lower end of the rotating spindle so as to stabilize the radial direction and the axial direction, but the permanent magnet disposed at the upper end of the rotating spindle. Positioning with the help of a bearing facilitates cooling and makes it possible to float the rotating spindle stably.

  However, flywheel power storage devices, high-speed turbine devices, and the like are desired to further increase the rotational speed of the flywheel while ensuring the stability of the rotating body without generating large vibrations in the rotor during rotation. .

JP 7-42737 JP 2006-234124 A

  It is desired that a high-speed rotating body in a flywheel power storage device, a high-speed turbine device, and the like be rotated at a higher speed. An object of the present invention is to suppress the occurrence of vibration during high-speed rotation and to maintain a stable state not only when the high-speed rotating body rotates but also when stationary. The present invention secures stability that has been impossible only with a bearing until now by supporting the rotating body in a stable state by making the center of gravity of the rotating body lower than the support bearing portion.

  In the high-speed rotating device of the present invention, a flywheel is fixed on a rotating spindle to form a rotating body, and a fixed side of a bearing that supports the rotating body in a non-contact manner is attached to a housing. Only one superconducting bearing is provided as a bearing that supports the lower end of the rotating body in a non-contact manner. The flywheel is composed of a disk part and a cylindrical part fixed or integrally formed on the outer periphery thereof, and this cylindrical part is arranged so as to be located on the outer peripheral side of the superconducting bearing.

  The center of gravity of the rotating body including the flywheel is set lower than the support point of the superconducting bearing supporting the weight of the rotating body. At the center of the upper surface of the disc portion of the flywheel, the end of the rotating main shaft is fixed, and the permanent magnet for the superconducting bearing is fixed to the lower surface of the disc portion. A generator motor is provided, a stator side of the generator motor is attached to the housing, and a permanent magnet on the rotor side is attached to the upper surface of the disk portion of the flywheel.

  The superconducting bearing is composed of a cylindrical superconductor attached to the housing, a radial permanent magnet and an axial permanent magnet facing the superconductor in the radial direction and the axial direction.

  The present invention can be maintained in a stable state by not providing a bearing for supporting the upper end side of the rotating body, and by supporting only the lower end side of the rotating body in a non-contact manner by the superconducting bearing. However, the present invention can include a permanent magnet bearing that supports the upper end side of the rotating body in a non-contact manner. This permanent magnet bearing is configured by stacking a plurality of permanent magnets in the axial direction on the rotor side and the stator side, and further sandwiching a spacer between the permanent magnets.

According to the present invention, the following effects can be obtained as compared with the conventional flywheel power storage device.
(1) By using the so-called Yajiro Bey principle in which the center of gravity of a rotating body such as a flywheel or a high-speed turbine is lower than the support point of the support bearing, the rotating body stably supports levitation not only when rotating but also when stationary. be able to.
(2) The rotating body can easily rotate stably and at an ultra-high speed.
(3) Since it is easy to increase the moment of inertia, it is easy to increase the amount of stored flywheel power.
(4) Since it is basically a one-point support structure like a jirobee, the power storage device can be easily downsized as a whole.

It is a figure which shows the flywheel system structure for electric power storage which actualized the high-speed rotation apparatus of this invention. It is a conceptual diagram of a superconducting bearing. It is a conceptual diagram of a generator motor. It is a figure which shows the generator motor embodied as a 2 phase 4 pole brushless DC motor. It is a figure which shows the experimental apparatus of the superconducting flywheel for electric power storage. It is a figure which illustrates the case where the flywheel for electric power storage is applied to an energy charging / discharging system. It is a free run measurement experiment schematic diagram at the time of applying a flywheel for power storage to an energy storage system. It is a conceptual diagram of a permanent magnet bearing. It is a graph which shows the free run characteristic result in a permanent magnet bearing and a superconducting bearing, (a) shows an upper displacement sensor (near a permanent magnet bearing), (b) shows a measurement result of a lower displacement sensor (near a superconducting bearing) Yes. It is a figure which shows the energy storage state at the time of applying as a charge energy amount ensuring system. It is a figure which shows a flywheel discharge state when the instantaneous drop is produced in load in the energy charging system to which the flywheel for power storage is applied. It is a figure explaining the prior art disclosed by patent document 1. FIG. It is a figure which shows the non-contact bearing apparatus disclosed by patent document 2. FIG. It is a conceptual diagram for demonstrating operation | movement of each bearing apparatus shown in FIG.

  FIG. 1 is a diagram showing a power storage flywheel system structure embodying a high-speed rotation device of the present invention. The illustrated power storage flywheel system can be further embodied in an energy charging / discharging system, an energy storage system, a charging energy amount securing system, an energy charging system, and the like, as described in the section of the embodiment described later. In order to cool the superconductor, the exemplary power storage flywheel system is housed in a chamber and refrigerated after being evacuated by a vacuum exhaust device, as described later with reference to FIG. Cool to a temperature at which the superconducting phenomenon occurs by using a machine or liquid nitrogen. By making the vacuum high, it is possible to suppress the windage loss when the flywheel rotates and to provide a heat insulating effect when cooling the superconductor.

  As shown in FIG. 1, a copper base and a back plate coupled to the freezer are provided on a freezer cooled by a refrigerator, and a fixed side (superconductor) of a superconducting bearing is provided on the base. The stator side of the generator motor is attached to the plate. At the lower end, the rotor that is supported in a non-contact manner by the superconducting bearing is constituted by a generator motor and a flywheel attached to the rotating main shaft. The lower end of the rotation main shaft fixes the center of the flywheel disc part upper surface side. A permanent magnet for a superconducting bearing is fixed to the lower surface side of the disc portion of the flywheel. Alternatively, it is possible to extend the rotating main shaft downward and attach the flywheel disc and the permanent magnet for the superconducting bearing to the lower end of the rotating main shaft.

  The flywheel is composed of a disc portion and a cylindrical portion functioning as a weight fixed coaxially (or integrally formed) on the outer periphery of the lower surface thereof, and this cylindrical portion is located on the outer peripheral side of the superconducting bearing so as to cover it. Be placed. The flywheel disc portion is attached immediately above the permanent magnet for the superconducting bearing, and a part of the permanent magnet (axial permanent magnet) is embedded and attached to the lower surface side of the flywheel disc portion. The permanent magnet of the generator motor is also embedded and attached to the upper surface side of the flywheel disc. A cylindrical portion is provided on the outer periphery on the lower surface side of the flywheel disc portion to lower the center of gravity of the flywheel so that the center of gravity of the rotating body (rotor) is lower than the support point of the superconducting bearing. The support point of the superconducting bearing is the center point of the support force in each direction, considering the support force separately in the radial direction and the thrust direction.

  When stationary, the center of gravity of the rotor is lower the lower the support point of the superconducting bearing, the more stable it is. During rotation, the rotor is deformed due to centrifugal force, etc., so that it varies depending on the rotational speed of operation, but is lower than the support point of the superconducting bearing. As a result, the rotating body can be stably levitated and supported not only when rotating but also when stationary due to the so-called Yajirobei principle. Furthermore, the length of the rotor in the axial direction is shortened by embedding and attaching a part of the permanent magnet for the rotor of the generator motor and the permanent magnet for the superconducting bearing to the upper surface side and the lower surface side of the flywheel disc part, respectively. Can do. Moreover, the center of gravity of the rotor can be further lowered by not necessarily requiring a permanent magnet bearing (see FIG. 13) on the upper end side of the rotor as conventionally required. However, the vibration can be further reduced by providing a permanent magnet bearing (see FIGS. 7 and 8) on the upper end side of the rotor.

  The lower end side of the rotor is rotatably supported by a repulsive superconducting bearing. The superconducting bearing attached to the lower end of the rotor in the axial direction is composed of a cylindrical superconductor attached to a housing (base), a radial permanent magnet and an axial permanent permanent facing the superconductor in the radial direction and the axial direction. It consists of a magnet. The radial permanent magnet is radially opposed to the inside of the cylindrical superconductor and supports the lower end of the rotating spindle in the radial direction, while the axial permanent magnet is axially opposed to the upper end surface of the cylindrical superconductor. Support the rotor in the direction. With these two-way permanent magnets, the lower end of the rotor can be positioned and supported in a levitating manner to stabilize the radial direction and the axial direction. Thus, the center of gravity of the rotor can be lowered by positioning and supporting the lower end of the rotor by using only one of the superconducting bearings. As shown in FIG. 1, a spacer made of a non-magnetic material provided between a radial permanent magnet and an axial permanent magnet is used to prevent interference between the bidirectional magnets and to attach two types of permanent magnets having different sizes. In preparation for.

Next, the “superconducting bearing”, “generator motor”, and “flywheel” shown in FIG. 1 will be further described.
(Superconducting bearing)
FIG. 2 is a conceptual diagram of a superconducting bearing. The permanent magnet for the superconducting bearing is composed of both radial and axial permanent magnets attached to the lower surface of the flywheel disc at the lower end of the rotor. By using permanent magnets in the radial direction and the axial direction for the superconducting bearing that supports the weight of the rotor, vibration of the rotor during rotation can be suppressed. Radial permanent magnets increase the surface area if they are stacked and extended in the axial direction even if the diameter of the permanent magnet portion is small (for example, four), increasing the levitation force, and supporting the weight even at high rotational speeds. In addition, it is easy to provide a vibration damping effect (shaft shake prevention effect). Further, the axial permanent magnets mainly support the weight of the rotor, and at the same time suppress vibrations in the radial direction and the axial direction.

For example, an annular oxide high temperature superconductor (for example, a cylindrical body having an outer diameter of 45 mm and a width of 16 mm) is used on the stator side of such a superconducting bearing. For example, a plurality of annular rare earth magnets (outer diameter: 24 mm, width: 4 mm) are arranged as radial permanent magnets (exemplified as four) on the rotor side located inside the superconductor and facing in the radial direction. . The magnetic poles of the rare earth magnets are arranged so that the magnetic poles of the permanent magnets adjacent to NS-SN-NS-SN are the same, and are arranged so that the magnetic flux is easily captured by the superconductor. Also, the axial magnet embedded in the lower end surface of the flywheel uses a ring-shaped magnet with an outer diameter larger than that of the radial permanent magnet, for example, an outer diameter of 42 mm, facing the oxide superconductor in the axial direction. Yes.
(Generator motor)
FIG. 3 is a conceptual diagram of a generator motor. The generator motor rotates the flywheel in a non-contact state or, conversely, generates power from the rotationally driven flywheel rotor. FIG. 4 shows a generator motor embodied as a two-phase four-pole brushless DC motor of coils X1, Y1 and coils X2, Y2. The permanent magnet for the rotor of the DC motor is installed in the upper part of the flywheel. This permanent magnet can be composed of a ring-type neodymium magnet. The permanent magnet for the rotor is arranged so as to face the stator coil of the generator motor, and the magnetic pole is read by the Hall element arranged on the stator side and the coil to be excited is switched. As described above, the illustrated generator motor is configured as a well-known brushless DC motor. The switching of excitation during driving uses a two-phase excitation method in which opposing coils are connected in pairs and two poles are excited by a power amplifier. For example, when the Hall element senses the S pole, the coils X1 and Y1 are excited to the N pole, and the coils X2 and Y2 are excited to the S pole. As a result, the S pole in front of the Hall element is attracted to the coil X1 that is excited to the N pole. Thus, the drive system that simultaneously excites the two phases on the motor side increases the rotational force and rotates the flywheel. The number can be increased. Further, since the illustrated motor is a permanent magnet motor, it also functions as a generator that generates power according to Fleming's right hand rule.
(Flywheel)
As shown in FIG. 1, the flywheel is composed of a disk part and a cylindrical part fixed or integrally formed on the outer periphery thereof, and this cylindrical part is arranged so as to be positioned and covered on the outer peripheral side of the superconducting bearing. Is done. The disc portion and the cylindrical portion of the flywheel can be integrated, or can be fixed together after being configured separately. As the material, a heavy non-magnetic material such as fiber reinforced plastics (FRP) can be used.

  Since the center of gravity of the flywheel is lowered, it is stable and less likely to collapse even when there is no rotation. During rotation, the stability of the gyro effect is added, so the rotation continues without falling down. Moreover, it is effective also for energy storage by providing the cylindrical part which functions as a weight on the flywheel outer peripheral side. The amount of rotational kinetic energy E [J] that can be stored in the flywheel is expressed by equation (1). Here, m [kg]: mass of rotating body, r [m]: radius of rotating body, ω [rad / s]: angular velocity of rotation.

E = m / 4 (rω) ² (1)

  FIG. 5 is a diagram showing an experimental apparatus for a superconducting flywheel for power storage. This experimental apparatus mainly consists of a vacuum chamber containing a superconducting flywheel, a control PC, a rotor rotational angle position sensor, a superconductor cooling refrigerator, a vacuum pump, an instantaneous voltage drop simulation circuit, and a temperature recovery heater. The instantaneous voltage drop simulation circuit is controlled by a control PC. The refrigerator is used to cool the superconductor to a temperature at which superconductivity occurs, and by using a vacuum evacuation system, the chamber is highly evacuated to reduce windage loss during rotation of the flywheel and to insulate the superconductor. Bring.

  FIG. 6 is a diagram illustrating a case where a power storage flywheel is applied to an energy charge / discharge system. The device consists of a flywheel, an instantaneous voltage drop simulation circuit, a control PC, and the like. The rotational speed of the flywheel is constantly monitored by a tachometer, and the rotational speed in a certain range is maintained by a control PC. The normal 5V voltage can be instantaneously reduced to 3V by the instantaneous voltage drop simulation circuit. This instantaneous voltage drop is monitored by the control PC. When an instantaneous voltage drop is detected, the relay is switched by the control PC and power is supplied from the flywheel to the load.

  FIG. 7 is a schematic diagram of a free-run measurement experiment when the power storage flywheel is applied to an energy storage system. The rotor on which the flywheel is installed is supported in a non-contact manner by a permanent magnet bearing on the upper end side and by a superconducting bearing on the lower end side. In this state, the flywheel is rotationally driven by the generator motor, and the drive of the generator motor is stopped at an appropriate rotational speed. The rotation speed at that time is measured with a tachometer. Note that the displacement of the rotor during rotation of the flywheel is evaluated by an upper displacement sensor and a lower displacement sensor.

  Further, as shown in the figure, the vibration can be further reduced by providing a permanent magnet bearing on the upper end side of the rotor. FIG. 8 is a conceptual diagram of a permanent magnet bearing. The permanent magnet bearing attached to the upper end portion of the rotating main shaft includes a rotor-side permanent magnet fixed to the outer peripheral surface of the upper end of the rotating main shaft and a housing (shown in FIG. 1) via the permanent magnet mounting portion so as to face the permanent magnet. And a fixed permanent magnet attached to the back plate.

  In order to make the center of gravity of the rotor lower than the support point of the superconducting bearing portion, it is desirable to reduce the size of the permanent magnet bearing. In the illustrated permanent magnet bearing, a plurality of permanent magnets (illustrated as two) are stacked on the rotor side and the stator side in the axial direction, and a spacer (for example, 1 mm width) is used between the permanent magnets. ing. The permanent magnets have opposite polarities so that the lower permanent magnets attract each other, and the upper permanent magnets face each other with the same polarity so as to repel each other. Thus, by inserting the spacer, the upper (or lower) stator side permanent magnet and the lower (or upper) rotor side permanent magnet do not repel (or attract) each other in the axial direction. In addition, it is possible to achieve downsizing with a reduced thickness.

  FIG. 9 shows the results of free run characteristics of the permanent magnet bearing and the superconducting bearing, (a) shows the measurement result of the upper displacement sensor (near the permanent magnet bearing), and (b) shows the measurement result of the lower displacement sensor (near the superconducting bearing). Yes. The free run times shown in FIGS. 9 (a) and 9 (b) are both about 20 seconds and do not change much. Vibration during rotation was suppressed to about 0.03 mmo-p or less near the superconducting bearing and to about 0.12 mmo-p or less near the permanent magnet bearing. In the vibration characteristics, resonance occurs around 2,000 to 3,000 rpm. Vibration near the superconducting bearing is considerably suppressed.

  FIG. 10 is a diagram showing an energy storage state when applied as a charging energy amount securing system. When the rotational speed decreased to 4,000 rpm, the flywheel was rotated by a generator motor to 4,500 rpm, and it was confirmed that a certain amount of energy could be stored arbitrarily. The upper displacement and the lower displacement in the figure represent the vibration displacement measured by the upper displacement sensor and the lower displacement sensor (see FIG. 7). The minimum storage energy and maximum energy are 16.0 J (at 4,000 rpm) and 20.2 J (at 4,500 rpm), respectively. In addition, in storage at a rotational speed that causes resonance, the rotor vibration does not change during repeated driving of the generator motor, so this system is considered to be effective. In addition, it is considered that energy loss is reduced because there is no need to always charge with this system.

FIG. 11 is a diagram showing a flywheel discharge state when an instantaneous voltage drop is caused in a load in an energy charging system to which a power storage flywheel is applied. The power supply voltage (a), load voltage (b), fly It shows the situation of the wheel rotation speed (c), the upper displacement (d) measured by the upper displacement sensor (FIG. 7), and the flywheel energy (e). The rotational speed of the flywheel was 4,300 rpm, causing a voltage drop of about 100 ms at 3V. From Fig. 11, the power supply voltage drops from 5V to 3V in the vicinity of 20ms, and the power supply voltage returns to 5V when it is about 130ms, and it can be simulated that the instantaneous drop occurs for 110ms. Recognize. The power supply voltage once drops to 0V because the output voltage is switched by the relay circuit. The load voltage also drops at the stage of switching by the relay, but the instantaneous low withstand voltage instantaneous interruption time of the general-purpose inverter that is the most severe instantaneous interruption time based on the instantaneous low withstand voltage instantaneous data of the load equipment is 15 ms, This is not a problem because it is a requirement for instantaneous interruption time.

Claims (6)

In a high-speed rotating device in which a flywheel is fixed on a rotating spindle to constitute a rotating body, and a fixed side of a bearing that supports the rotating body in a non-contact manner is attached to a housing.
As a bearing that supports the lower end side of the rotating body in a non-contact manner, the bearing includes only one superconducting bearing attached to the lower end portion in the axial direction of the disc portion of the flywheel ,
The flywheel and the disc portion is constituted by a cylindrical portion which is fixed or integrally formed on the outer periphery thereof, and said cylindrical portion, spaced from the outer peripheral side is positioned on the outer peripheral side of the superconducting bearing And place it so that it covers
A high-speed rotating device comprising a center of gravity of the rotating body including the flywheel lower than a support point of a superconducting bearing supporting the weight of the rotating body.
2. The high-speed rotation according to claim 1, wherein an end of the rotating main shaft is fixed to the center of the upper surface of the disc portion of the flywheel, and a permanent magnet for the superconducting bearing is fixed to the lower surface of the disc portion. apparatus. The high-speed rotating device according to claim 1, further comprising a generator motor, wherein a stator side of the generator motor is attached to a housing, and a rotor-side permanent magnet is attached to an upper surface of a disc portion of the flywheel. 2. The high-speed rotating device according to claim 1, wherein the superconducting bearing is configured by a cylindrical superconductor attached to a housing, a radial permanent magnet and an axial permanent magnet facing the superconductor in a radial direction and an axial direction. . The high-speed rotating device according to claim 1, wherein a bearing for supporting the upper end side of the rotating body is not provided and only the lower end side of the rotating body is supported in a non-contact manner by the superconducting bearing. A permanent magnet bearing that supports the upper end side of the rotating body in a non-contact manner, and the permanent magnet bearing includes a plurality of permanent magnets axially stacked on the rotor side and the stator side, and The high-speed rotation device according to claim 1, wherein the high-speed rotation device is configured with a spacer interposed therebetween.

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