JP3820479B2 - Flywheel equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flywheel device used in a power storage device that converts surplus power into rotational kinetic energy of a flywheel and stores it.
[0002]
[Background Art and Problems to be Solved by the Invention]
As a flywheel device of this type, conventionally, a vertical rotating shaft provided with a flywheel is supported in a non-contact manner by two sets of upper and lower radial magnetic bearings and one set of axial magnetic bearings arranged around it, and the rotating shaft is driven by an electric motor. There is known one that rotationally drives the motor.
[0003]
In such a conventional flywheel device, each radial magnetic bearing is provided with two pairs (four) of electromagnets arranged so as to sandwich the rotating shaft from two radial directions orthogonal to each other, and the axial magnetic bearing is a rotating body. A pair of (two) electromagnets arranged so as to sandwich the flange portion from the axial direction are provided. Therefore, ten electromagnets are required for the entire apparatus, and there is a problem that power consumption by the electromagnets is large. Moreover, since it is necessary to arrange | position an electric motor and three sets of magnetic bearings along an axial direction around a rotating shaft, a rotating shaft becomes long. For this reason, there is a problem that the weight of the rotating shaft increases, the natural frequency decreases, and high-speed rotation becomes difficult.
[0005]
An object of the present invention is a flywheel that solves the above problems, reduces the power consumption by the electromagnet, shortens the rotating shaft or the rotating body, and eliminates the problem caused by the length of the rotating shaft or the rotating body. To provide an apparatus.
[0006]
[Means for Solving the Problems and Effects of the Invention]
The flywheel device according to the present invention is a flywheel device in which a vertical rotation shaft provided with a flywheel at an intermediate portion in the axial direction is supported in a non-contact manner by a plurality of sets of magnetic bearings. A tapered tapered bearing surface is formed at a location from the axially intermediate portion toward the axial end direction, and is arranged at a predetermined interval in the circumferential direction at a fixed portion around each bearing surface. Axial / radial combined magnetic bearings each having an electromagnet are provided, and each magnetic bearing is a motor-integrated magnetic bearing in which a suction coil and a motor coil are wound around a common magnetic pole. is there.
[0007]
The rotary shaft is supported in a non-contact manner by two sets of upper and lower axial / radial magnetic bearings provided around the tapered bearing surface. Accordingly, the number of magnetic bearings can be reduced by one compared to the conventional flywheel device in which three sets of magnetic bearings are provided. Moreover, since each magnetic bearing has a three-pole structure composed of three electromagnets, the number of electromagnets is six, which is four less than the conventional flywheel device provided with ten electromagnets. I'm sorry. For this reason, the power consumption by an electromagnet can be made small. Furthermore, since each magnetic bearing is a motor-integrated magnetic bearing in which a suction coil and a motor coil are wound around a common magnetic pole, there is no need to provide a separate magnetic pole for the electric motor. In addition, it is not necessary to separately provide a magnetic pole for the motor around the rotating shaft as described above, and the number of magnetic bearings provided around the rotating shaft can be reduced as described above. Can be shortened. Therefore, the weight of the rotating shaft can be reduced, the natural frequency can be increased, and high-speed rotation is possible.
[0008]
For example, an axial auxiliary magnetic bearing that supports at least a part of the weight of the rotary shaft is provided between the axial end face of the flywheel and a fixed portion facing the axial end face. In that case, preferably, the axial auxiliary magnetic bearing includes a permanent magnet provided on a lower end surface of the flywheel and a permanent magnet provided on the fixed portion so as to repel the permanent magnet.
[0009]
Since the axial position of the rotating body can be controlled by controlling the axial and radial magnetic bearings, the axial auxiliary bearing only needs to support at least part of the weight of the rotating shaft. Since at least a part of the weight of the rotary shaft is supported by the axial auxiliary bearing, the power consumption by the electromagnet of the axial / radial combined magnetic bearing can be further reduced. Even when the axial auxiliary magnetic bearing is composed of an electromagnet, it is only necessary to support the weight of the rotating shaft, and therefore, it is only necessary to pass a constant excitation current through the electromagnet. Therefore, the power consumption by the electromagnet of the axial auxiliary magnetic bearing is reduced. The increase is small. Moreover, it is only necessary to provide electromagnets on the end face of the flywheel and the opposing surface of the fixed part, and the increase in the length of the rotating shaft due to this is small. When the axial auxiliary magnetic bearing supports the weight of the rotating shaft by the repulsive force of the permanent magnet, there is no increase in power consumption due to the axial auxiliary magnetic bearing. It is only necessary to provide a permanent magnet, and the increase in the length of the rotating shaft due to this is small.
[0010]
For example, the axial / radial combined magnetic bearing is a sensorless magnetic bearing sharing the suction coil as a position detection coil .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Several embodiments of the present invention will be described below with reference to the drawings.
[0013]
1 to 3 show an embodiment (first embodiment) in which the present invention is applied to an inner rotor type flywheel device.
[0014]
As shown in FIG. 1, the flywheel device includes a housing (fixed portion) (1) and a vertical rotation shaft (2) disposed inside thereof. A flywheel (3) is formed at substantially the center in the vertical direction (axial direction) of the outer periphery of the rotating shaft (2). A tapered surface that faces diagonally upward is formed on the outer periphery above the flywheel (3) of the rotating shaft (2), and a bearing surface (upper bearing surface) in which the large-diameter portion of the lower half or more also serves as the rotor part ( 4) The small diameter part near the upper end is the detected surface (upper detected surface) (5). An axial / radial combined magnetic bearing (upper magnetic bearing) (6) is placed on the inner peripheral part of the housing (1) facing the upper bearing surface (4), and the inner surface of the housing (1) facing the upper detected surface (5). A position sensor unit (upper sensor unit) (7) is provided around the circumference. On the outer periphery below the flywheel (3) of the rotating shaft (2), the bearing surface (lower bearing surface) that also serves as the rotor facing the upper bearing surface (4) opposite to the axial direction (8) And a detected surface (9) are formed, and axial and radial combined magnetic bearings (lower magnetic bearing) (10) and a position sensor unit (lower sensor unit) are formed on the inner peripheral portion of the housing (1) facing each other. (11) is provided. An axial auxiliary magnetic bearing (13) is provided between the lower end surface of the flywheel (3) and the upward annular surface (12) of the housing (1) facing the flywheel (3). Annular grooves (14), (15) are formed on the outer periphery of the upper end and lower end of the rotating shaft (2), and touchdown bearings (16), (17) are provided on the inner periphery of the housing (1) corresponding thereto. ing.
[0015]
The upper magnetic bearing (6) has a three-pole structure composed of three sets of attracting electromagnets (18), the details of which are shown in FIG. These electromagnets (18) are formed integrally with one annular stator portion (19) provided on the inner periphery of the housing (1) at equal intervals (120 degree intervals) in the circumferential direction. Six magnetic poles (18a) protruding radially inward are integrally formed on the inner circumference of the stator portion (19) at equal intervals (60-degree intervals) in the circumferential direction. The suction surface (18b) of each magnetic pole (18a) is a tapered surface corresponding to the bearing surface (4). Two adjacent magnetic poles (18a) constitute a set of electromagnets (18), and a common attraction coil (20) is provided at the tip of the two magnetic poles (18a) of each set of electromagnets (18). It is rolled up. The magnetic bearing (6) is a motor-integrated magnetic bearing having an electric drive function for rotationally driving the rotating shaft (2), and a motor coil (21) is wound around the proximal end portion of the six magnetic poles (18a). It has been.
[0016]
The lower magnetic bearing (10) has the same configuration as the upper magnetic bearing (6), and the corresponding parts are denoted by the same reference numerals.
[0017]
As shown in detail in FIG. 3, the upper sensor unit (7) has two pairs (four pieces) arranged so as to sandwich the detected surface (5) of the rotating shaft (2) from the two radially outer sides orthogonal to each other. ) Position sensor (22). The detection surface (22a) of each position sensor (22) is a tapered surface corresponding to the detected surface (5).
[0018]
The lower sensor unit (11) has the same configuration as that of the upper sensor unit (7), and corresponding parts are denoted by the same reference numerals.
[0019]
The axial auxiliary magnetic bearing (13) is provided on the annular permanent magnet (23) provided on the lower end surface of the flywheel (3), and on the annular surface (12) of the housing (1) so as to be opposed thereto. It consists of an annular permanent magnet (24), and these repel each other.
[0020]
The attraction coil (20) of each electromagnet (18), the motor coil (21) of each magnetic pole (18a), and the position sensor (22) are connected to a control device (not shown), and the control device is connected to the motor coil (21). An alternating current (driving current) is supplied to the power source, and a direct current (excitation current) supplied to the suction coil (20) is controlled based on an output signal of the position sensor (22).
[0021]
In the above flywheel device, at least a part of the weight of the rotating shaft (2), preferably substantially the whole, is supported by the magnetic repulsive force of the permanent magnets (23) and (24) of the auxiliary magnetic bearing (13). By supplying a direct current from the controller to the suction coil (20), the electromagnet (18) attracts the tapered bearing surfaces (4) and (8), and the rotating shaft (2) is not axially or radially non-rotated. Contact supported. By supplying alternating current from the control device to the motor coil (21), a rotating magnetic field is generated in the stator section (19) and the rotating shaft (2) is driven to rotate, and the magnitude and frequency of this alternating current are controlled. By doing so, the rotational driving force and rotational speed of the rotating shaft (2) are controlled. Each position sensor (22) outputs a signal corresponding to the size of the gap between the detection surface (5) and (9) facing the detection surface (22a) thereof. Then, the control device detects the position of the rotary shaft (2) in the axial direction and the radial direction by calculating the output signal of the position sensor (22), and based on the detection result, the suction coil (20) By controlling the supplied direct current, the position of the rotating shaft (2) in the axial direction and the radial direction is controlled.
[0022]
In the case of the first embodiment, the position sensor units (7) and (11) detect the position of the rotating shaft (2) using four position sensors (22), but the magnetic bearings (6) (10) The position of the rotary shaft (2) can also be detected using three position sensors arranged in the same manner as the electromagnet (18).
[0023]
FIG. 4 shows another embodiment (second embodiment) in which the present invention is applied to an inner rotor type flywheel device. The second embodiment is obtained by removing the upper and lower position sensor units (7) and (11) from the first embodiment, and corresponding portions are denoted by the same reference numerals.
[0024]
In the case of the second embodiment, the magnetic bearings (6) and (10) are used to detect the position of the rotating shaft (2) by using the attracting coil (20) of the electromagnet (18) for non-contact support of the rotating shaft (2). This is a so-called sensorless magnetic bearing shared as a coil. And a control apparatus detects the position of the axial direction of a rotating shaft (2) and a radial direction based on the change of the exciting current which flows into an attraction coil (20). Others are the same as those in the first embodiment.
[0025]
In the case of the first and second embodiments, the auxiliary magnetic bearing (13) supports the weight of the rotating shaft (2) by the repulsive force of the permanent magnets (23) and (24). ) And the weight of the rotating shaft (2) may be supported by the attractive force of a permanent magnet provided on the lower annular surface of the housing (1) facing the upper end surface. Further, an electromagnet may be provided instead of the permanent magnets (23) and (24), and the weight of the rotating shaft (2) may be supported by the repulsive force or attractive force of the electromagnet. In some cases, an axial auxiliary magnetic bearing may not be provided.
[0038]
The configuration of each part of the flywheel device is not limited to that of the above embodiment, and can be changed as appropriate.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a flywheel device showing a first embodiment of the present invention.
FIG. 2 is a sectional view taken along line II-II in FIG.
3 is a cross-sectional view taken along line III-III in FIG.
FIG. 4 is a longitudinal sectional view of a flywheel device showing a second embodiment of the present invention .
[Explanation of symbols]
(1) Housing (fixed part)
(2) Rotating shaft
(3) Flywheel
(4) (8) Bearing surface
(6) (10) Axial / radial magnetic bearings
(13) Axial auxiliary magnetic bearing
(18) Electromagnet
(23) (24) Permanent magnet

Claims (4)

In a flywheel device that supports a vertical rotation shaft provided with a flywheel in an axially intermediate portion in a non-contact manner by a plurality of sets of magnetic bearings,
Tapered bearing surfaces that are tapered from the middle in the axial direction toward the end of the shaft are formed at two locations above and below the outer periphery of the rotary shaft with respect to the flywheel. Axial and radial magnetic bearings each having three electromagnets arranged at predetermined intervals in the direction are provided, and each of the magnetic bearings has a common magnetic pole wound with a suction coil and a motor coil. A flywheel device characterized by being a body-type magnetic bearing.   2. The fly according to claim 1, wherein an axial auxiliary magnetic bearing that supports at least a part of the weight of the rotary shaft is provided between an axial end face of the flywheel and a fixed portion facing the axial end face. Wheel device.   The axial auxiliary magnetic bearing includes a permanent magnet provided on a lower end surface of the flywheel and a permanent magnet provided on the fixed portion so as to repel the permanent magnet. 2 flywheel devices. 2. The flywheel device according to claim 1, wherein the axial / radial combined magnetic bearing is a sensorless magnetic bearing sharing the attraction coil as a position detecting coil.

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