JP2001352725A - Generator motor for flywheel energy storage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a generator motor for flywheel energy storage capable of forming a structure capable of reducing iron loss generated when the generator motor is in a free running condition, into as simple a structure as possible. SOLUTION: A shield member 35 of ferromagnetic substance is formed so as to move along the direction of the rotating shaft 33a of a rotor 33. In operating the generator motor as a generator/motor, the shield member 35 is drawn out to make a permanent magnet 32 of the rotor 33 function as a field magnet. At the time of free running of the generator motor, the shield member 35 is inserted in between the rotor 33 and a stator core 34 to magnetically shield the magnetic flux of the permanent magnet.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a generator motor for storing flywheel energy, and is particularly useful when applied to a permanent magnet generator motor for storing flywheel energy. . [0002] A flywheel energy storage device is known as an energy storage device. This flywheel energy storage device stores energy as rotational energy of a flywheel, and is often combined with a generator motor. By driving the generator motor as a motor with a flywheel as a load, the flywheel is rotated to store rotational energy associated with the flywheel, while the generator motor is driven as a flywheel load, This is because the generator motor is operated as a generator to convert the rotational energy stored in the flywheel into electric energy for use. [0003] A flywheel device using this type of generator motor has four types of operation modes. Standby state during pre-rotation, energy input state in which the generator motor is operated as a motor to input energy to the flywheel, energy input storage state in which the input energy is stored and retained as flywheel rotational energy, and generator motor is generated This is an energy release state in which the apparatus operates as a machine and extracts energy stored and held in the flywheel as electric energy. [0004] In this type of flywheel energy storage device according to the prior art, the stator and the rotor of the generator motor generally face each other through a predetermined gap in any operation mode. On the other hand, as this type of generator motor, a PM (permanent magnet) generator motor, which can be expected to have higher efficiency, is frequently used. In this PM generator motor, a permanent magnet for excitation is fixed on the surface of the rotor. Make up the field. That is, in the generator motor according to the related art, the permanent magnet of the rotor is always opposed to the stator core of the stator through a predetermined gap. There is a problem that iron loss occurs in the stator core due to the magnetic flux generated by the magnet. In order to reduce or eliminate such iron loss,
The stator is formed to be movable in the axial direction and is not affected by the magnetic flux generated by the rotor.The rotor is formed to be movable in the axial direction and the effect of the magnetic flux generated by the rotor is fixed. A configuration that does not affect the child is conceivable. FIG. 4 is an explanatory view conceptually showing a permanent magnet generator motor in which the former measure is taken, and FIG. As shown in FIG. 4, a permanent magnet generator motor 1
Is a rotor 2 with a permanent magnet attached to the surface of the rotor core.
And a stator 3. The rotor 2 is connected to a rotation shaft 5 of the flywheel 4. Thus, the flywheel 4 is rotated to store rotational energy by causing the permanent magnet generator motor 1 to function as a motor, and the rotational energy of the flywheel 4 is converted to electrical energy by functioning as a generator. Here, the stator 3 is configured to be movable in the axial direction. More specifically, a nut 6 having a female screw is fixed to the stator 3, and a screw shaft 7 is screwed to the nut 6. The screw shaft 7 is configured to be rotationally driven by an electric motor 8, so that the stator 3 moves in one direction along the axial direction via the nut 6 during normal rotation, and moves in the opposite direction during reverse rotation. It has become. When the permanent magnet generator motor 1 is operating as a generator / motor, the stator 3 is at a position facing the rotor 2 and functions as a normal permanent magnet generator motor. On the other hand, in a free-run state during energy storage, the stator 3 is moved to a position farther from the position of the rotor 2 so that the magnetic flux generated by the permanent magnet of the rotor 2 does not affect the outside. Thus, almost no magnetic flux passes through the stator 3 or other parts, and it becomes possible to suppress iron loss during free running of the generator motor. For this reason, the stator 3 is formed so as to be movable by a distance equal to or longer than the magnetic pole. As shown in FIG. 5A, a permanent magnet generator / motor 11 has a rotor 12 having a permanent magnet adhered to the surface of a rotor core, and a stator 13. Rotor 12
Is connected to the rotating shaft 15 of the flywheel 14.
Thus, by rotating the flywheel 14 by making the permanent magnet generator motor 11 function as a motor to store rotational energy, the rotational energy of the flywheel 14 is converted into electric energy by making it function as a generator. Here, the rotor 12 is configured to be movable in the axial direction. More specifically, the rotating shaft 12a of the rotor 12 is supported by a slide bearing 19, and is formed to be movable in the axial direction. The moving range at this time is set to a distance equal to or longer than the magnetic pole.
The sliding bearing 19 has a bearing 19a and a sleeve 19b as shown in FIG. 5 (b) by extracting and enlarging this part. The bearing 19a reduces the friction in the rotating direction, and the sleeve 19b reduces the rotating shaft. The smoothness of the axial movement of 12a is ensured. The thrust bearing 20 is formed so as to be axially movable integrally with the rotating shaft 12a. Although not shown in the figure, similar to the case shown in FIG. 4, a moving means such as a screw shaft is provided, and the rotor 12 is moved by this moving means. When the permanent magnet generator motor 11 is operating as a generator / motor, the stator 13 is at a position facing the rotor 12 and functions as a normal permanent magnet generator motor. On the other hand, in the free-run state during energy storage, the rotor 12 is moved to a position farther from the position of the stator 13 so that the magnetic flux generated by the permanent magnet of the rotor 12 does not affect the outside. As a result, almost no magnetic flux passes through the stator 13, and iron loss during free running of the generator motor can be suppressed. The permanent magnet generator-motor according to the prior art as described above has a structure in which a heavy rotor or a stator is moved, so that the moving operation itself is not performed. Not only would it be a difficult task, but the moving mechanism would be large and expensive. SUMMARY OF THE INVENTION In view of the above prior art, the present invention relates to a flywheel energy storage for obtaining a structure capable of minimizing iron loss generated when a generator motor is in a free-run state as simple as possible. An object is to provide a generator motor. The structure of the present invention to achieve the above object is as follows. 1) The flywheel is connected to the rotating shaft of the flywheel and functions as an electric motor to rotate the flywheel to store rotational energy, and also functions as a generator to convert the rotational energy of the flywheel to electric energy. In a generator motor for storing flywheel energy, the field magnet can be magnetically shielded by a movable ferromagnetic shield member. 2) In the generator motor for storing flywheel energy described in 1) above, the field magnet is constituted by a permanent magnet. 3) In the generator motor for storing flywheel energy described in 1) above, a field magnet is constituted by a permanent magnet fixed to the surface of a rotor core, and this permanent magnet is formed into a cylindrical strong magnet together with the rotor. The shield member is configured to be movable so that it can be covered by a shield member made of a magnetic material. Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory view conceptually showing a generator motor according to an embodiment of the present invention, in which FIG.
(B) is the figure seen from the front. As shown in both figures, the generator motor according to the present embodiment is a permanent magnet generator motor, and a plurality of (four in the figure) permanent magnets 32 having N poles and S poles are circumferentially arranged on the surface of a cylindrical rotor core 31. , And a stator core 3 opposed to the rotor 33.
And 4. That is, the rotor 33 forms a field. Shield member 35 made of ferromagnetic material in a cylindrical shape
Are formed so as to be able to be taken in and out of a gap between the rotor 33 and the stator core 34. That is, the gap between the rotor 33 and the stator core 34 is formed to have a thickness equal to or greater than the thickness of the shield member 35, and the permanent magnet 32 is covered from outside by moving the shield member 35 in the axial direction. And magnetically shielded. Here, various linear movement mechanisms of the shield member 35 are conceivable, but an example is as follows. FIG. 2 is an explanatory view conceptually showing the generator motor according to the present embodiment, particularly focusing on the moving mechanism of the shield member 35. As shown in the figure, this example is an application of a linear induction motor to a moving mechanism. That is, the linear induction motor 36 includes a cylindrical stator 36a, and a movable element 36b disposed inside the stator 36a and linearly moving in the axial direction. Here, the mover 36b is fixed to the end of the shield member 35. As a result, the linear induction motor 36
The shield member 35 linearly moves integrally with the mover 36b in accordance with the linear movement of the mover 36b accompanying the driving of. During this movement, the shield member 35 slides along the outer peripheral surface of the permanent magnet 32, and when the shield member 35 comes into contact with and covers the outer peripheral surface of the permanent magnet 32, the shield member 35 and the rotor 33 are in this state. It is designed to rotate integrally. When the mover 36b moves in the axial direction,
It is necessary to support the mover 36b with respect to the rotating shaft 33a. FIG. 3 shows an example of this support structure. FIG.
(A) shows a rotating shaft 33 on the inner peripheral surface of a cylindrical mover 36b.
The figure shows a support structure in which a disk-shaped member 37 having a hole substantially the same as the outer diameter of a is fixed, and the disk-shaped member 37 contacts the outer peripheral surface of the rotating shaft 33a to support the mover 36b. In FIG. 3B, a plurality of support members 38 extending in the radial direction are arranged on the inner peripheral surface of the cylindrical movable member 36b in the circumferential direction, and a roller 39 can be rotated at the tip of each support member 38. 3 shows a supporting structure in which the supporting member 38 supports the supporting member 38 via the roller 39 by attaching the supporting member 38 to the supporting member 38. When the generator motor is operating as a generator / motor, the shield member 35 is drawn out of the gap between the rotor 33 and the stator core 34 by the linear induction motor 36 and the permanent magnet 32 Function as a field magnet. On the other hand, in a free-run state during energy storage, the shield member 35 is moved by the driving of the linear induction motor 36 to cover the permanent magnet 32. As a result, a closed magnetic circuit including the shield member 35 is formed, and the magnetic flux generated by the permanent magnet 32 returns to the rotor 33 through the shield member 35. Therefore, leakage of the magnetic flux generated by the permanent magnet 32 to the stator core 34 side can be reduced as much as possible, and loss due to iron loss generated during free running of the generator motor can be suppressed as much as possible. In the above-described embodiment, the shield member 35 is formed of a cylindrical member. However, the shape is not limited to this. What is necessary is just to make it the optimal shape according to the shape of the part to be shielded. According to the present invention, the shield member is moved to cover the field magnet when the generator motor is in the free-run state, as described in detail with the above embodiments. Can be magnetically shielded, so that iron loss of the generator motor in the free-run state can be reduced as much as possible. At the same time, since the moving part for the magnetic shield is constituted only by the shield member, the magnetic shield structure including the structure of the moving part can be simplified. The cost of the device can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view conceptually showing a generator motor according to an embodiment of the present invention, where (a) is a view from the side and (b) is a view from the front. is there. FIG. 2 is an explanatory view conceptually showing the generator motor according to the embodiment of the present invention, particularly focusing on a moving mechanism of the shield member. FIG. 3 is an explanatory diagram conceptually showing a support structure of a shield member in the moving mechanism shown in FIG. 2 by extracting this portion. FIG. 4 is an explanatory view conceptually showing a generator motor for storing flywheel energy according to the related art. FIG. 5 is an explanatory view conceptually showing another generator motor for storing flywheel energy according to the related art. [Description of Signs] 31 Rotor core 32 Permanent magnet 33 Rotor 33a Rotary shaft 34 Stator core 35 Shield member 36 Linear induction motor 37 Disk-shaped member 38 Support member 39 Roller

   ────────────────────────────────────────────────── ─── Continuation of front page    F term (reference) 5H002 AA03 AB01                 5H590 AA02 AA05 AA10 AB03 AB06                       CC02 CC18 EA01 EA07 EA13                       EB02 EB14 FA03 FA05 FC05                 5H621 BB07 GA01 GA04                 5H622 CA02 CA05 CA13 PP03 PP16                       PP18

Claims (1)

Claims 1. A flywheel, which is connected to a rotating shaft of a flywheel, functions as an electric motor, rotates the flywheel to store rotational energy, and functions as a generator, thereby forming a flywheel. A flywheel energy storage motor for converting rotational energy into electric energy, wherein the movable field shield member is made of a ferromagnetic material so that a field magnet can be magnetically shielded. Generator motor. 2. The generator motor for flywheel energy storage according to claim 1, wherein the field magnet is constituted by a permanent magnet. 3. A generator motor for storing flywheel energy according to claim 1, wherein a field magnet is constituted by a permanent magnet fixed to a surface of a rotor core, and the permanent magnet is formed into a cylindrical shape together with the rotor. A generator motor for storing flywheel energy, wherein the shield member is configured to be movable so that it can be covered by a shield member made of a ferromagnetic material.