JP3470217B2 - Flywheel type power storage device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flywheel power storage device used in electric vehicles and the like.

[0002]

2. Description of the Related Art A flywheel type electric power storage device converts surplus electric power into rotational kinetic energy of a flywheel and stores the electric power. A vertical rotating body having a flywheel is supported by a bearing device and also serves as a generator and electric motor. It can be rotated at high speed.

In such an electric power storage device, in order to reduce bearing loss during high speed rotation, a rotating body is supported by a control type magnetic bearing device in a non-contact manner in a radial direction (radial direction) and an axial direction (axial direction). There has been proposed a method of holding the same in a predetermined operating position. This type of conventional magnetic bearing device includes two sets of control type radial magnetic bearings that support two axial positions of a rotor in a non-contact manner in the radial direction, and one set of control radial magnetic bearings that support the rotor in a non-contact manner in the axial direction. Type axial magnetic bearing. Normally, each radial magnetic bearing is composed of four electromagnets, and each axial magnetic bearing is composed of two electromagnets.
Ten electromagnets are used in the entire magnetic bearing device.
The four electromagnets of the radial magnetic bearing are orthogonal to each other.
The rotors are arranged so as to sandwich the rotating body in each of the two radial directions, and the electromagnets of each pair attract the rotating body in opposite directions in the respective radial directions. An exciting current that is a combination of a constant steady current and a control current is supplied to each pair of electromagnets, and by controlling the control current based on the radial displacement of the rotating body, the rotating body moves to the radial operating position. It is supposed to be retained. The two electromagnets of the axial magnetic bearing are arranged so as to form a pair with the flange-like portion of the rotating body sandwiched from both sides in the axial direction, and these electromagnets attract the rotating body in opposite directions in the axial direction and It is designed to support weight. An exciting current that is a combination of a constant steady current and a control current is supplied to the pair of electromagnets, and the control current is controlled based on the displacement of the rotating body in the axial direction, so that the rotating body is held at the operating position in the axial direction. It is supposed to be done.

Further, in the electric power storage device, the rotor is mechanically moved in the radial and axial directions when it is no longer supported by magnetic bearings such as when power supply is stopped or when the rotor is largely displaced due to impact force or the like. In order to support and protect the magnetic bearing, a touchdown bearing including a ball bearing or the like is provided.

Particularly in the case of a power storage device mounted on an electric vehicle or a hybrid type electric vehicle, downsizing of the device,
It is desirable to reduce the weight, rotate the rotating body at a high speed, and reduce the power consumption, but this is difficult in the conventional device as described below.

First, in the power storage device, it is necessary to increase the size of the flywheel in order to improve the power storage efficiency, which causes the weight of the rotating body to increase. Since the weight of the rotating body is supported only by the axial magnetic bearing of the magnetic bearing device, the electromagnet of the axial magnetic bearing becomes large, and the weight of the electromagnet and the power consumption by the electromagnet increase. Further, when the power storage device is installed in an electric vehicle or the like, a large displacement may occur in the rotating body due to disturbance such as vibration or impact force. In order to prevent this, it is necessary to increase the supporting force, that is, the rigidity of each magnetic bearing of the magnetic bearing device, and for that purpose, it is necessary to increase the attractive force of the electromagnet of each magnetic bearing. In order to increase the attraction force of the electromagnet, it is necessary to increase the size of the electromagnet and increase the control current, which increases the weight of the electromagnet and the power consumption of the electromagnet.

Further, in the conventional magnetic bearing device, since the magnetic bearings are provided at three locations in the axial direction of the rotating body as described above, the rotating body becomes long, and the device becomes large in size and heavy in weight. Become. Also, since 10 large electromagnets are used in the entire magnetic bearing device, the weight of these is large,
Power consumption is also large. Further, since a power amplifier is required for each electromagnet, a total of 10 power amplifiers are required, and power consumption by these is large.

Further, since the rotating body becomes long, its natural frequency is lowered, and high-speed rotation becomes difficult.

Some radial magnetic bearings are composed of three electromagnets, but in that case as well, eight electromagnets are required for the entire magnetic bearing device, which again has the same problem as described above.

As a magnetic bearing device in which the number of electromagnets is reduced, tapered surfaces facing the mutually opposite sides in the axial direction are formed at two locations in the axial direction of the rotating body, and the rotating body is tapered around these tapered surfaces. It has been proposed that an axial / radial magnetic bearing having four or three electromagnets that are attracted in a direction orthogonal to is provided.

In the case of this magnetic bearing device, the total number of electromagnets is 8 or 6. However, since it is necessary to form a highly accurate tapered surface, special processing is required for the rotating body.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a flywheel type power storage device which can be made compact, lightweight and have low power consumption.

It is an object of the present invention to provide a flywheel type power storage device which is capable of reducing the size and weight of the device, increasing the speed of a rotating body, and reducing power consumption.

[0014]

A flywheel type power storage device according to the present invention comprises a vertical rotating body having a flywheel, an electric motor for rotating the rotating body, which also serves as a power generator, and the rotating body. Of the control type magnetic bearing and the axial of the upper and lower sides, which support the fixed portion in a non-contact manner with respect to the fixed portion in the radial direction and the axial direction and hold it at a predetermined operating position
Displacement sensor having displacement sensor and radial displacement sensor
Based on the output signal of the
A control type magnetic bearing device for controlling a control current, and in a state where the rotating body is supported in the operating position by the control type magnetic bearing in a non-contact manner, no force is exerted on the rotating body, and the rotating body is in the operating position. Gap of hydrodynamic bearing only when displaced from
And a dynamic pressure bearing device that applies a force in the direction opposite to the displacement direction to the rotating body by the dynamic pressure of the lubricant .

During rotation, the rotating body is supported in a non-contact manner in the radial direction and the axial direction by the magnetic bearing device and is held in the operating position. When the rotating body is displaced from the operating position due to disturbances such as vibration and impact force, a force is applied to the rotating body in the hydrodynamic bearing device in the direction opposite to the displacement direction, and this force prevents further displacement, and the rotating body It is returned to the operating position by the magnetic bearing device. When the rotating body is displaced downward from the operating position due to gravity, the upward force acting on the rotating body from the hydrodynamic bearing device prevents further displacement, and the rotating body is returned to the operating position by the magnetic bearing device. That is, a part of the weight of the rotating body is supported by the dynamic pressure bearing device. Therefore, it is not necessary to support the weight of the rotating body only by the magnetic bearing of the magnetic bearing device. Further, even if the rotating body is displaced from the operating position, further displacement is prevented by the force from the dynamic pressure bearing device, so it is not necessary to increase the rigidity of each magnetic bearing of the magnetic bearing device too much. Therefore, the electromagnet of each magnetic bearing can be downsized, and the control current can be reduced. As a result, the weight of the electromagnet can be reduced,
The power consumption of the electromagnet can be reduced.

When the rotational driving force and the support by the magnetic bearing device are lost due to the stop of power supply, the rotating body is displaced downward from the operating position by gravity, but the rotating body is kept in the dynamic bearing device while the rotational speed is high to some extent. Is supported in a non-contact state by a part of the weight, and when the number of rotations decreases, the rotating body is mechanically supported in the radial direction and the axial direction by the dynamic pressure bearing device and supported by the dynamic pressure bearing device. Stop in the state where it was stopped. This eliminates the need for conventional touchdown bearings.

As described above, according to the present invention, it is possible to reduce the size and weight of the device and reduce the power consumption.

For example, in the dynamic pressure bearing device, an upper dynamic pressure bearing that exerts a downward force on the upper portion of the rotating body when the rotating body is displaced upward from the operating position, and the rotating body is in the operating state. And a lower dynamic pressure bearing that exerts an upward force on the lower portion of the rotating body when displaced downward from the position.

According to this structure, in any of the cases where the rotary body is displaced from the operating position in any of the radial directions, is displaced upward in the axial direction, and is displaced downward in the axial direction. Further, it is possible to prevent further displacement by the force from the dynamic pressure bearing device, and when the rotation drive force and the support by the magnetic bearing device are lost due to the stop of power supply, the dynamic pressure bearing device reduces the weight of the rotating body. The part can be supported and stopped.

For example, the upper dynamic pressure bearing is a spherical dynamic pressure bearing with a spiral groove provided between the upper end of the rotating body and the fixed portion, and the lower dynamic pressure bearing is the lower end of the rotating body. And a spherical dynamic pressure bearing with a spiral groove provided between the fixed portion and the fixed portion. A spherical grooved dynamic bearing with a spiral groove is composed of a supporting portion provided on the fixed portion side and a supported portion provided on the rotating body, and a concave spherical surface is provided on either one of the supporting portion and the supported portion. A convex spherical surface that fits into the concave spherical surface is formed, and a spiral groove is formed on either one of the concave spherical surface and the convex spherical surface.

[0021] With this structure, when the rotating body is displaced upward from the operating position by using the hydrodynamic bearing having a relatively simple structure, a downward force is applied to the upper portion of the rotating body so that the rotating body operates. When displaced downward from the position, an upward force can be applied to the lower part of the rotating body to support a part of the weight of the rotating body.

For example, each of the magnetic bearings is provided with three or four electromagnets arranged around the rotating body, and each of the electromagnets has a radial magnetic pole projecting radially inward from two locations in the axial direction and axial magnetic poles radially possess axial pole
The radial magnetic poles project radially inward from the magnetic poles , the radial magnetic poles face the outer peripheral surface of the rotary body to attract the rotary body in the radial direction, and the axial magnetic poles are the shafts of the rotary body. The rotating body is adapted to be sucked in the axial direction so as to face the surface facing the direction.

In this case, the magnetic bearing faces the outer circumferential surface of the rotating body and attracts it in the radial direction, and the magnetic pole faces the axially facing surface of the rotating body and attracts it in the axial direction. Since it has the magnetic poles in the axial direction, the rotating body can be attracted both in the radial direction and in the axial direction by one set of magnetic bearings. Therefore, the rotating body can be supported by two sets of magnetic bearings in a non-contact manner. You can Therefore, the number of electromagnets required for the entire magnetic bearing device is eight when each magnetic bearing has four electromagnets, and six when each magnetic bearing has three electromagnets. In any case, the number is reduced by 2 from the conventional one. As the number of electromagnets decreases, so does the number of power amplifiers, which reduces their weight and current consumption. Further, since the magnetic bearings may be provided only at two positions in the axial direction of the rotating body, the rotating body is shortened and the weight is reduced. Moreover, since the rotating body is shortened, its natural frequency is increased and the rotating body can be rotated at high speed.

Therefore, the size and weight of the device can be reduced, the speed of the rotating body can be increased, and the power consumption can be reduced.
Further, no special processing is required for the rotating body, and only the axial length can be shortened by using the rotating body of the conventional specification.

Preferably, in each of the magnetic bearings, the radial magnetic poles of the all electromagnets have the same polarity, and the axial magnetic poles have the same opposite polarity.

By doing so, the change in the magnetic flux around the rotating body facing the radial magnetic poles is reduced, so that the eddy current generated on the surface of the rotating body due to the rotation is reduced, and the rotation loss is reduced. The same applies to the axial magnetic pole portion, which reduces the rotation loss due to the magnetic bearing device and increases the power storage efficiency.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a power storage device for an electric vehicle will be described below with reference to the drawings.

FIG. 1 shows an example of the electrical construction of the main parts of an electric vehicle.

The electric vehicle includes a wheel driving electric motor (30),
Inverter that converts DC to AC and drives the motor (30)
(31), a flywheel type power storage device (32), a power control device (33) for controlling the inverter (31) and the power storage device (32), and the like are provided. Power control device
The (33) is equipped with a storage battery for driving the wheel driving electric motor (30), the power storage device (32), etc., and is adapted to be connected to an external charging power source (34) as required. There is.

An example of the power storage device (32) is schematically shown in FIG. 2, and the structure of the main part thereof is shown in FIG.

The power storage device comprises a vertically cylindrical closed housing (1) which constitutes a fixed portion and is relatively long in the vertical direction, and a vertical shaft-like rotating body (2) arranged in the housing (1).
, A control type magnetic bearing device (35), a dynamic pressure bearing device (15), and a permanent magnet type synchronous motor (5) for both power generation.

In the following description, the axis of the rotating body (2) in the axial direction (vertical axis) is the Z axis, and one radial axis (horizontal axis) orthogonal to the Z axis is the X axis, the Z axis and the X axis. The other radial axis (horizontal axis) orthogonal to is the Y axis.

The housing (1) is integrally formed by connecting a plurality of parts, and the inner diameter of the lower end is larger than that of the other parts. In addition, the inside of the housing (1) is kept in a vacuum state of, for example, about 10 ^-1 to 10 ^-3 Torr by an appropriate means (not shown) in order to prevent windage damage.

The rotating body (2) is concentrically arranged in the center of the housing (1). A perforated disc-shaped flywheel (7) located inside the large diameter lower end of the housing (1) is fixed to the lower end of the rotating body (2). The flywheel (7) is for storing surplus power as rotational kinetic energy.

The magnetic bearing device (35) controls the position of the rotating body (2) in the radial direction (X-axis and Y-axis direction) and the axial direction (Z-axis direction) so as to drive the rotating body (2) in a predetermined operation. It is for supporting the position in a non-contact state, and is provided with two sets of control type magnetic bearings (3) (4), displacement sensors (10) (11) (12) and magnetic bearing control device (36). ing.

The magnetic bearings (3) and (4) are provided at two upper and lower positions in the middle part of the housing (1). Upper Magnetic Bearing (3)
Is fixed in the housing (1) so as to sandwich the rotating body (2) from both sides in the X-axis direction, and sucks the rotating body (2) to the upper side in the Z-axis direction and both sides (outer side) in the X-axis direction. The pair of X-axis direction electromagnets (8) and the rotating body (2) are fixed in the housing (1) so as to sandwich the rotating body (2) from both sides in the Y-axis direction. And a pair of Y-axis direction electromagnets (37) for attracting to both sides of. Similarly, the lower magnetic bearing (4) includes a pair of X-axis direction electromagnets (9) for attracting the rotating body (2) to the lower side in the Z-axis direction and both sides in the X-axis direction, and the rotating body (2).
And a pair of Y-axis direction electromagnets (not shown) for attracting to the lower side in the Z-axis direction and to both sides in the Y-axis direction.

X-axis direction electromagnets (8) of the upper magnetic bearing (3)
Has a shape having a pair of magnetic poles (8a), (8b) projecting inward in the X-axis direction from two positions in the axial direction, and these magnetic poles (8a)
An electric wire (coil) (8c) is wound around (8b). The upper axial magnetic pole (8a) projects more inward than the lower radial magnetic pole (8b). The radial magnetic poles (8b) face the outer peripheral surface near the upper end of the large-diameter middle portion of the rotating body (2) with a slight gap therebetween, and attract the rotating body (2) to the outside in the X-axis direction. The axial magnetic pole (8a) projects above the upper annular end surface of the upper end of the intermediate portion of the rotating body (2) and faces the end surface with a slight gap, thereby rotating the rotating body (2) in the Z-axis direction. Aspirate above.
The Y-axis direction electromagnets (37) of the upper magnetic bearing (3) also have the same configuration as the X-axis direction electromagnets (8) and function in the same manner. Figure 3
Is the magnetic pole in the axial direction of the Y-axis direction electromagnet (37) (37a)
Then, the radial magnetic poles are represented by reference numeral (37b), and the electric conductors are represented by reference numeral (37c). The axial magnetic poles (8a) (37a) of all electromagnets (8) (37) of the upper magnetic bearing (3) have the same polarity and
b) (37b) has the same opposite polarity. The X-axis direction electromagnets (9) of the lower magnetic bearing (4) are connected to the X-axis from two points in the axial direction.
Shape with a pair of magnetic poles (9a) (9b) protruding inward in the axial direction
None of Jo, these poles (9a) (9b) to the electric wire (9c) is wound. The lower axial magnetic pole (9a) projects more inward than the upper radial magnetic pole (9b). The radial magnetic pole (9b) is
The rotating body (2) is opposed to the outer peripheral surface in the vicinity of the lower end of the large-diameter middle portion with a slight gap, and the rotating body (2) is sucked outward in the X-axis direction. The axial magnetic pole (9a) projects below the lower annular end face of the lower end of the middle part of the rotating body (2) and faces this end face with a slight gap, thereby rotating the rotating body (2) in the Z-axis direction. Aspirate down. Each Y-axis direction electromagnet of the lower magnetic bearing (4) has the same structure and function as the X-axis direction electromagnet (9). The axial magnetic poles (9a) of all electromagnets (9) of the lower magnetic bearing (4) have the same polarity, and the radial magnetic poles (9b) have the same opposite polarity.

An axial displacement sensor (10) for detecting the axial displacement of the rotating body (2) is provided at an appropriate position in the housing (1), for example, the inner surface of the top wall (1a). In the vicinity of the upper magnetic bearing (3), two pairs of radial displacement sensors for detecting the radial displacement of the upper part of the rotating body (2), that is, sandwiching the rotating body (2) from both sides in the X-axis direction. A pair of X-axis displacement sensors (11) fixed to the housing (1) for detecting the displacement of the rotating body (2) in the X-axis direction, and the rotating body (2) sandwiched from both sides in the Y-axis direction. A pair of Y-axis direction displacement sensors (not shown) fixed to the housing (1) for detecting the displacement of the rotating body (2) in the Y-axis direction are provided. Similarly, in the vicinity of the lower magnetic bearing (4), two pairs of radial displacement sensors for detecting the radial displacement of the lower part of the rotating body (2), that is, a pair of X-axis direction displacement sensors (12), A pair of Y-axis direction displacement sensors (not shown) are provided.

The electromagnets (8) (37) (9) and the displacement sensors (10) (11) (12) of the magnetic bearings (3) (4) are the magnetic bearing control device (36).
Is connected to each electromagnet (8) from this controller (36)
(37) Excitation current is supplied to (9). Magnetic bearing controller (3
Electric power for driving 6) is supplied from the storage battery of the power control device (33). The exciting current is a combination of the steady current, the axial control current, and the radial control current. The value of the steady current is constant and does not change depending on the output signals of the displacement sensors (10) (11) (12). Then, the control device (36) controls each magnetic bearing based on the output signal of the axial displacement sensor (10).
By controlling the magnitude of the axial control current of each electromagnet (8) (37) (9) of (3) (4), the axial position of the rotating body (2) is controlled and the radial displacement sensor ( By controlling the magnitude of the radial control current of each electromagnet (8) (37) (9) of each magnetic bearing (3) (4) based on the output signal of (11) (12), the rotating body (2 The radial position of) is controlled. The rotating body (2) is usually
It is supported in a non-contact manner in the operating position in the center of the housing (1).

The electric motor (5) functions as an electric motor at the time of storing electric power and as a generator at the time of taking out electric power, and is provided in an intermediate portion of the housing (1) between the upper and lower magnetic bearings (3) and (4). There is. The electric motor (5) consists of a rotor (13) fixed to the middle part of the large diameter middle part of the rotating body (2) and a stator (14) fixed to the inner circumference of the housing (1) around it. It is configured. The stator (14) of the electric motor (5) is connected to the electric motor control device (38), and the electric motor control device (38) is connected to the electric power control device (33). The motor controller (38) is an inverter that converts DC into AC and drives the motor (5) as an electric motor, and the AC generated by the motor (5) is converted into DC and supplied to the power controller (33). A converter and the like are provided.

The hydrodynamic bearing device (15) applies to the rotating body (2) a force in the direction opposite to the displacement direction when the rotating body (2) is displaced from the operating position, that is, a force in the direction of returning the rotating body to the operating position. The rotating body (2) and the upper dynamic bearing (16) that exerts a downward force on the upper part of the rotating body (2) when the rotating body (2) is displaced upward from the operating position. It is provided with a lower dynamic pressure bearing (17) that exerts an upward force on the lower part of the rotating body (2) when it is displaced downward from the operating position. Upper Dynamic Bearing (16)
Is a spherical dynamic pressure bearing with a spiral groove provided between the upper end of the rotating body (2) and the housing (1).
A stepped columnar support member (18) that constitutes a support portion fixed to the inner surface of the top wall (1a) of (1) so as to project downward, and a projecting upward projection at the center of the upper end of the rotating body (2). And a columnar supported member (19) that constitutes the supported portion. Supported member (1
Hemispherical recess (1 with an upward concave spherical surface on the top surface of 9)
9a) has been formed. At the lower end of the support member (18), there is a hemispherical convex portion (18) having a downward convex spherical surface and fitted in the concave portion (19a).
Although a) is formed and a detailed illustration is omitted, a spiral groove is formed on the convex spherical surface. The lower hydrodynamic bearing (17) is a spherical hydrodynamic bearing with a spiral groove provided between the lower end of the rotating body (2) and the housing (1), and the inner surface of the bottom wall (1b) of the housing (1). A columnar support member (20) that constitutes a support section fixed to the upper part of the rotary body,
(2) is provided with a stepped cylindrical supported member (21) that constitutes a supported portion fixed in a downward protruding shape at the center of the lower end. A hemispherical recess (20a) having an upward concave spherical surface is formed on the upper end surface of the support member (20). At the lower end of the supported member (21), there is formed a hemispherical convex portion (21a) which has a downward convex spherical surface and fits into the concave portion (20a). A spiral groove is formed.
Recesses of the upper supported member (19) and the lower supporting member (20)
Lubricants of low volatility for generating dynamic pressure at the time of rotation of the rotating body (2) are stored in (19a) and (20a) and are interposed between the convex spherical surface and the concave spherical surface.

In the state before the above-mentioned electric power storage device (32) is operated, electric power is not supplied to the magnetic bearings (3) (4) and the electric motor (5), and the rotating body (2) does not move. Pressure Bearing (16) (17)
It is supported by and is stationary. For more details,
The convex portion (21a) of the supported member (21) of the lower dynamic pressure bearing (17) is tightly fitted into the concave portion (20a) of the supporting member (20), and the convex spherical surface and the concave spherical surface are in close contact with each other through a lubricant. As a result, the rotating body (2) is supported in the axial direction and the radial direction to support the weight thereof, and the convex portion (18a) of the supporting member (18) of the upper dynamic pressure bearing (16) is supported by the supported member (19). ) And the convex spherical surface and concave spherical surface partially contact each other, so that the rotor (2)
Are supported in the radial direction, and the rotating body (1) stands still with a slight inclination. In such a stationary state of the rotating body (2), the rotating body (2) is the surrounding magnetic bearings (3) (4), the displacement sensors (10) (11) (12), the stator of the electric motor (5). The dimensions of each part are determined so as not to interfere with (14).

In the above electric vehicle, a power storage device
When the electric power is stored in the (32), the electric power control device (33) is connected to the external charging power source (34). Then, the storage battery of the power control device (33) is charged by the electric power supplied from the power supply (34), the magnetic bearing control device (36) is driven by the storage battery, and the rotating body is rotated by the magnetic bearings (3) and (4). (2) is supported in the operating position without contact. At this time, the power control device (33) is
(5) is made to function as an electric motor, and the storage battery drives the electric motor (5) through the inverter of the electric motor control device (38).
As a result, the rotating body (2) is rotated, and the electric power supplied from the storage battery is converted into rotational kinetic energy of the flywheel (7) of the rotating body (2) and stored. Power control device (3
When the storage battery in 3) is fully charged and the rotation speed of the rotating body (2) rises to a predetermined value, the power control device (33) is disconnected from the power supply (34) and the electric vehicle is operated in that state. It During operation, the storage battery of the power control device (33) drives the wheel driving electric motor (30) and other electric devices (not shown). Further, the power control device (33) causes the electric motor (5) to function as a generator, and if necessary, the electric power generated by the electric motor (5) is transmitted via the converter of the electric motor control device (38) to the electric power control device (33). )
It is supplied to the storage battery of and is charged. And the rotating body
If the rotation speed of (2) has decreased to some extent, the power control device (22) is connected to the charging power source (34) as described above to charge the storage battery and store the power of the power storage device (32). Be seen.

In the state where the rotating body (2) is supported by the magnetic bearings (3) and (4) in the operating position in a non-contact manner, the upper and lower dynamic pressure bearings (1
6) In (17), the convex spherical surface of the convex portion (18a) (21a) and the concave portion (19a)
a) The centers of the concave spherical surfaces of (20a) are almost coincident with each other, and there is a slightly larger and almost uniform gap between the convex spherical surface and the concave spherical surface,
Even if the lubricant is interposed between the convex spherical surface and the concave spherical surface, the dynamic pressure bearings (16) (17) exert almost no force on the rotating body (2). In Fig. 1, the gap between the rotating body (2) and the magnetic bearings (3) (4) and the displacement sensors (10) (11) (12), the rotor (13) and the stator (14) of the electric motor (5). ), And the gaps between the convex portions (18a) (21a) and the concave portions (19a) (20a) of the dynamic pressure bearings (16) (17) are exaggerated.

During operation of the power storage device (32), when the rotating body (2) is displaced from the operating position due to disturbance such as vibration or impact force, the rotating body (2) is moved to the rotating body (2) at the dynamic pressure bearings (16) (17). A force in the direction opposite to the displacement direction acts, and this force prevents further displacement, and the rotating body (2) is returned to the operating position by the magnetic bearings (3) and (4). For example, when the rotating body (2) is displaced above the operating position, the convex portion (18a) of the upper dynamic pressure bearing (16)
Since the gap between the concave part (19a) and the concave part (19a) is reduced, the dynamic pressure of the lubricating oil interposed between the convex spherical surface and the concave spherical surface causes the supported member (1
A downward force is applied to 9), and the upper part of the rotating body (2) is a dynamic bearing.
Receives downward force from (16). At this time, the lower dynamic pressure bearing
In (17), since the gap between the convex portion (21a) and the concave portion (20a) increases, the dynamic pressure bearing (17) generates almost no force, and the lower part of the rotating body (2) has the dynamic pressure bearing ( Very little power from 17). As a result, the rotating body (2) as a whole receives a downward force opposite to the displacement direction. If the rotating body (2) is displaced below the operating position, the lower part of the rotating body (2) receives an upward force from the lower hydrodynamic bearing (17), and the upper part of the rotating body (2) rises similarly. Since the hydrodynamic bearing (16) receives almost no force, the rotating body (2) as a whole receives an upward force opposite to the displacement direction. As the rotating body (2) moves in the radial direction in parallel or tilts, the convex portions (18a) (21a) become concave (19a) (20a) in the upper and lower dynamic pressure bearings (16) (17). When it is displaced from the operating position in the radial direction, the convex parts (18a) (21a) and the concave part (1a)
9a) and (20a), the clearance decreases in the displacement direction and increases in the opposite direction, so the supported members (19) (21) are the dynamic pressure bearings (16) (17).
Receives a force in the direction opposite to the displacement direction. Therefore, in either case, the rotating body is
Further displacement of (2) is prevented and the rotating body (2) is returned to the operating position by the magnetic bearings (3) (4). as mentioned above,
When the rotating body (2) is displaced downward from the operating position due to gravity, the upward force acting on the rotating body (2) from the hydrodynamic bearing (17) prevents further displacement, and the rotating body (2) Returned to operating position by magnetic bearings (3) (4). That is, a part of the weight of the rotating body (2) is supported by the dynamic pressure bearing (17). Therefore, the magnetic bearings (3) (4) alone
It is not necessary to support the weight of (2). Also, even if the rotating body (2) is displaced from the operating position, the force from the dynamic pressure bearings (16) (17) prevents further displacement, so each magnetic bearing
(3) It is not necessary to increase the rigidity in (4) so much. Therefore, the electromagnets (8) (37) (9) of the magnetic bearings (3) (4) can be downsized and the control current can be reduced, and as a result, the electromagnets (8) (37) (9) The weight can be reduced, and the power consumption of the electromagnets (8) (37) (9) can be reduced.

When the storage battery of the power control device (33) is discharged and electric power is no longer supplied to the electric motor (5) and the magnetic bearings (3) and (4) of the electric power storage device (32), rotation driving by the electric motor (5) is performed. Since the force is lost, the rotating body (2) gradually decelerates. Also, since the bearing force of the magnetic bearings (3) (4) is lost, the rotating body (2)
Is displaced downward from the operating position due to gravity, but the rotating body (2) is supported in a non-contact state by the dynamic pressure bearings (16) and (17) while the rotational speed is high to some extent, and a part of its weight is When it is supported and the number of rotations decreases, the rotating body (2) moves to the dynamic pressure bearings (16) (1
It is mechanically supported in the radial and axial directions by 7) and stops while being supported by the dynamic pressure bearings (16) and (17).

In the above-mentioned electric power storage device (32), the magnetic bearings (3) and (4) of the magnetic bearing device (36) are one set so that the rotor (2) can be attracted both in the radial direction and in the axial direction. Therefore, the rotating body (2) can be supported in a non-contact manner by a total of eight electromagnets (8), (37) and (9) of the two sets of magnetic bearings (3) and (4). Compared to the device, the number of electromagnets is reduced by 2, and the number of power amplifiers for driving the electromagnets is reduced accordingly. For this reason,
The size of the device can be reduced, and the weight and power consumption can be reduced.
Moreover, since it is only necessary to provide two sets of magnetic bearings (3) and (4) around the rotating body (2), the length of the rotating body (2) is longer than that of the conventional one that requires three sets of magnetic bearings. Can be shortened, and therefore, the natural frequency of the rotating body (2) can be increased to rotate at high speed.

In the radial magnetic bearing of the conventional magnetic bearing device, a substantially horseshoe-shaped electromagnet having a pair of magnetic poles protruding inward in the radial direction from two locations in the circumferential direction of the rotating body is often used, and this is 4 in the circumferential direction. Individually arranged. In that case, a pair of magnetic poles of each electromagnet has polarities opposite to each other, and four magnetic poles of opposite polarities are arranged in the rotation direction of the rotating body. Therefore, eddy current is generated on the surface of the rotating body due to the rotation, and the rotation loss due to the eddy current is large. On the other hand, in the above-mentioned power storage device (32), in each magnetic bearing (3) (4), all electromagnets
(8) (37) (9) radial magnetic poles (8b) (37b) (9b) have the same polarity and axial magnetic poles (8a) (37a) (9a) have the same opposite polarity. Therefore, the change in the magnetic flux around the rotor (2) facing the radial magnetic poles (8b) (37b) (9b) and the axial magnetic poles (8a) (37
a) The change in the magnetic flux around the rotating body (2) facing (9a) is also small, so that the eddy current generated on the surface of the rotating body (2) due to the rotation is small, and the rotation loss is small. Therefore, the power storage efficiency of the device (32) is increased.

FIG. 4 shows an embodiment in which the above power storage device (32) is applied to a hybrid electric vehicle.

In this case, in the automobile, in addition to the same motor for wheel (30), inverter (31), power storage device (32), power control device (33) as in the above, an engine (39) such as a gasoline engine is used. ), And a generator (40) driven by rotation of the engine (39).

In the above automobile, while the vehicle is running, the engine (39) rotates to drive the generator (40) and the generated power is supplied to the power control device (33) to charge the storage battery. In addition, the wheel drive electric motor (30) and other electric devices are driven. When not using a large amount of electric power, the electric power control device (33) causes the electric motor (5) to function as an electric motor, and the surplus electric power from the generator (40) is supplied to the inverter (31) of the electric motor control device (38). The electric power is supplied to the electric motor (38) via the electric motor (38) to drive the rotating body (2) to store electric power. The engine (39) can be stopped while the vehicle is stopped. Conversely, when a large amount of power is needed, a power control device
(33) makes the electric motor (5) function as a generator, and the electric motor (5)
The electric power generated in (1) is taken out via the converter of the electric motor control device (38), and the electric current and the storage battery drive the electric motor (30) for driving the vehicle. Others are the same as the above-mentioned embodiment.

In the case of this embodiment, the surplus current can be stored in the power storage device (32), and when a large current is required, the current can be taken out from the power storage device (32) and used, so that the engine (39) Can be of low power.

In the above embodiment, each of the magnetic bearings (3) and (4) is arranged around the rotating body (2) at equal intervals in the circumferential direction, and four electromagnets (8) (37) (9) are arranged. ), The magnetic bearing may include three electromagnets arranged at equal intervals in the circumferential direction around the rotating body. Also in that case, the number of electromagnets is reduced by two as compared with the conventional magnetic bearing device of the same type.

The structure of the magnetic bearing device (35) is not limited to that of the above-mentioned embodiment, but can be changed appropriately. For example, the magnetic bearing device may be provided with two sets of radial magnetic bearings and one set of axial magnetic bearings as in the conventional case. In that case, at least one set of radial magnetic bearings,
In addition to the position control function of the rotating body (2), it is possible to eliminate the electric motor (5) by having an electric drive function of rotationally driving the rotating body (2). Controlled radial magnetic bearings having a rotary drive function are known as levitation rotary motors or bearingless motors.

The structure of the dynamic pressure bearing device (15) is not limited to that of the above-mentioned embodiment, but can be changed appropriately. For example, a spiral groove may be formed on the concave spherical surfaces of the concave portions (19a) (20a) of the supported member (19) and the supporting member (20). Also,
Each of the dynamic pressure bearings (16, 17) may be, for example, a conical surface dynamic bearing with a spiral groove having a concave conical surface and a convex conical surface.

The configuration of the other parts of the power storage device is not limited to that of the above embodiment, but can be changed as appropriate.

The configuration of the electric vehicle, the usage mode of the electric power storage device in the electric vehicle, and the like are not limited to those in the above-described embodiment, and can be changed as appropriate.

Furthermore, the present invention can be applied to power storage devices other than those for electric vehicles.

[Brief description of drawings]

FIG. 1 is an electric block diagram of a main part of an electric vehicle showing an embodiment of the present invention.

FIG. 2 is a schematic vertical sectional view of a flywheel power storage device.

FIG. 3 is an enlarged cross-sectional view taken along the line III-III in FIG.

FIG. 4 is an electric block diagram of a main part of an electric vehicle showing another embodiment of the present invention. Is.

[Explanation of symbols]

(1) Housing (fixed part) (2) Rotating body (3) (4) Magnetic bearing (5) Permanent magnet type synchronous motor for power generation (7) Flywheel (8) (9) X-axis direction electromagnet (8a) (9a) Axial magnetic pole (8b) (9b) Radial magnetic pole (15) Dynamic bearing device (16) (17) Hydrodynamic bearing (32) Flywheel power storage device (35) Magnetic bearing device (37) Y-axis direction electromagnet (37a) Axial magnetic pole (37b) Radial magnetic pole

Continuation of the front page (56) Reference JP-A-48-67644 (JP, A) JP-A-57-20573 (JP, A) JP-A-61-274119 (JP, A) JP-A-2-180312 (JP , A) JP 2-221808 (JP, A) JP 4-165119 (JP, A) JP 5-106634 (JP, A) JP 8-326530 (JP, A) JP 9-121477 (JP, A) JP 10-225017 (JP, A) Actual flat 6-23021 (JP, U) Special table 7-501197 (JP, A) Ryoichi Takahata, Takumi Ueyama, Hiromasa Higasa , Conceptual design of 1kWh class power storage flywheel rotating body supported by superconducting magnetic bearing, IEEJ Transactions D, September 1995, Vol. 115, No. 9, pp. 1198 to 1199 Hiromasa Higasa, Ryoichi Takahata , Hiroshi Imaizumi, Kenzo Miya, Structure and frequency response function of magnetic bearing using Y-system high temperature superconductor, Transactions of the Institute of Electrical Engineers of Japan D, October 1995, Vol. 115, No. 10, pp. 1276 to 1283 (58) investigated Field (Int.Cl. ^7, DB name) F16C 32/00 - 32/06 H02J 15/00

Claims (5)

(57) [Claims] 1. A vertical rotating body having a flywheel, an electric motor that also serves as a power generator for rotating the rotating body, and a predetermined portion that is supported by the rotating body in a non-contact manner in a radial direction and an axial direction with respect to a fixed portion. Two sets of upper and lower control type magnetic bearings, axial displacement sensor and radius which are held in the operating position
It has a displacement sensor and is based on the output signal of the displacement sensor.
A control type magnetic bearing device for controlling a control current of an electromagnet of a control type magnetic bearing, and a force is not exerted on the rotating body in a state where the rotating body is supported in the operating position by the control type magnetic bearing in a non-contact manner. , Only when the rotating body is displaced from the operating position
A flywheel-type power storage device comprising: a dynamic pressure bearing device that reduces a gap of a dynamic pressure bearing and applies a force in a direction opposite to a displacement direction to a rotating body by a dynamic pressure of a lubricant . 2. An upper dynamic bearing for applying a downward force to an upper portion of the rotating body when the rotating body is displaced upward from the operating position, and the rotating body is configured to perform the operation. The flywheel power storage device according to claim 1, further comprising: a lower dynamic pressure bearing that applies an upward force to a lower portion of the rotating body when displaced downward from the position. 3. The upper dynamic pressure bearing is a spherical dynamic pressure bearing with a spiral groove provided between the upper end of the rotary body and the fixed portion, and the lower dynamic pressure bearing is the lower end of the rotary body. The flywheel type electric power storage device according to claim 2, wherein the flywheel type electric power storage device is a spherical dynamic pressure bearing with a spiral groove provided between the fixed portion and the fixed portion. 4. Each of the magnetic bearings comprises three or four electromagnets arranged around the rotating body, and each of the electromagnets has a radial magnetic pole projecting radially inward from two locations in the axial direction. than have a axial magnetic axial pole radial poles
The radial magnetic poles have a shape protruding inward in the radial direction , the radial magnetic poles face the outer peripheral surface of the rotating body to attract the rotating body in the radial direction, and the axial magnetic poles face the axial direction of the rotating body. The flywheel power storage device according to any one of claims 1 to 3, wherein the rotary body is adapted to be attracted in the axial direction so as to face the surface. 5. In each of the magnetic bearings, the radial magnetic poles of the all electromagnet have the same polarity, and the axial magnetic poles have the same polarity opposite thereto. Flywheel power storage device.