JP5967653B2 - Flywheel integrated induction motor / generator - Google Patents

Description

  The present invention proposes an induction motor / generator integrated with a flywheel. In particular, surplus electrical energy is accumulated as kinetic energy in the flywheel in combination with a power generation facility or motor with large output fluctuations, while the kinetic energy of the flywheel is stored. It is useful when it is taken out as electric energy.

  Wind and sunlight are attracting attention as renewable energy. When this type of energy is converted into electric energy and used, there is a problem that it is impossible to operate at a constant output because it is difficult to obtain constant wind power and constant sunlight with little fluctuation. Therefore, when power is supplied using renewable energy, the generated power can be generated by building a system that combines power storage devices and flywheel devices that store electrical energy obtained by wind power generation and solar power generation. When the output exceeds the specified output, the surplus power is stored as electric energy or mechanical energy. On the other hand, the stored electric energy or mechanical energy is released when the generated power is lower than the predetermined output so that the output is constant. There is a case to devise.

  However, power storage devices are expensive per unit power storage capacity, and the construction of a system combined with a large capacity power storage device is problematic in terms of cost. Therefore, a power storage system that can be constructed at a relatively low cost and is combined with a flywheel device that is structurally robust is also widely used.

  FIG. 3 is an explanatory diagram schematically illustrating an example of a motor / generator with a flywheel, which is a type of power storage system according to the related art. As shown in the figure, the motor / generator II with a flywheel includes an electric motor / generator 01 and a flywheel device 02. In this example, a single rotating shaft 03 is connected to the motor / generator 01 and the flywheel device 02. The structure is shared by wheel devices. That is, the rotor (not shown in FIG. 3) of the electric motor / generator 01 and the rotating body 05 of the flywheel device 02, which is a heavy object that generates a large moment of inertia, are in the axial direction of one rotating shaft 03. Are arranged in series. The rotating shaft 03 is supported by bearings 07A and 07B so that both ends thereof can rotate.

  In the case of this example, the rotating body 05 is housed in a vacuum container 06 in which both ends of the cylindrical member are closed with lid members 09A and 09B and the inside is evacuated.

  In such a motor / generator II with a flywheel, for example, when surplus power is generated using wind power or sunlight, the motor / generator 01 is rotated by supplying this via a terminal 010. Drive. That is, at this time, the electric motor / generator 01 is driven as an electric motor, and a rotational driving force is transmitted to the rotating body 05 of the flywheel device 02 via the rotating shaft 03 along with the rotation. As a result, the rotating body 05 is rotationally driven, and a large mechanical energy is accumulated. Here, since the rotary body 05 in this example is accommodated in the vacuum vessel 06, the windage loss accompanying the rotation of the rotary body 05 can be reduced as much as possible.

  On the other hand, when the amount of power generated by wind power, sunlight, or the like decreases and the generated power is insufficient, the motor / generator 01 is driven as a generator by the mechanical energy of the rotating body 05 and the generator is connected via the terminal 010. Supply the generated power to the outside.

  By the way, in the motor / generator II with a flywheel shown in FIG. 3, the rotary shaft 03 passes through the lid member 09A and once protrudes to the outside of the flywheel device 02, and is also used as the rotary shaft of the motor / generator 01. Therefore, special contrivance is required regarding the structure in the penetrating portion of the rotating shaft 03. This is because it is necessary to employ a predetermined seal structure in the penetrating portion in order to maintain the vacuum of the vacuum container 06. Therefore, not only the structure of the penetrating portion of the rotating shaft 04 becomes complicated, but also maintenance for maintaining the function as the vacuum vessel 06 becomes troublesome.

  Various devices that achieve the same object as the motor / generator II with a flywheel shown in FIG. 3 by combining the motor / generator and the flywheel device have been conventionally proposed (see, for example, Patent Document 1). . However, since these are all connected in series with the rotating shaft of the motor / generator and the rotating shaft of the flywheel, the rotating body is placed in the vacuum vessel in order to improve the energy storage efficiency of the flywheel device. When housed, the structure in which the rotating shaft projects outside the vacuum vessel must be employed.

JP 2009-303284 A

  As described above, in the motor / generator II with a flywheel according to the prior art, it is necessary to make the rotary shaft 03 project outside the vacuum vessel 06, so that the seal structure and the like accompanying this becomes complicated, and maintenance and inspection are also performed. Has the problem of being troublesome.

  In view of the above-described prior art, the present invention simplifies the structure of the power storage device, and can not only provide a low-cost and small-sized device but also facilitate maintenance and the like. The purpose is to provide an electric motor / generator.

  A first aspect of the present invention that achieves the above object includes a cylindrical vacuum vessel that forms a sealed space held in a vacuum, and a rotary shaft that is rotatably supported at both ends by the vacuum vessel via bearings. A rotating body that is formed of a conductor that forms a closed circuit through which an eddy current can flow, is fixed to the rotating shaft and is configured to rotate integrally with the rotating shaft, and an exterior of the vacuum vessel The flywheel integrated induction motor / generator has three or more coils arranged at equal intervals around the periphery thereof.

  According to this aspect, it is possible to form a rotating magnetic field that rotates along the circumferential direction of the vacuum vessel with the coil disposed outside the vacuum vessel. As a result, a rotating magnetic field acts on the rotating body housed in the vacuum vessel. Therefore, an induction motor is formed by the coil and the rotating body, the slip s with respect to the rotation frequency of the rotating magnetic field becomes positive, and the rotating body is rotated. As a result, mechanical energy is accumulated in the rotating body. On the other hand, when the slip s with respect to the frequency of the rotating magnetic field becomes negative, an induction generator is formed by the coil and the rotating body, and the mechanical energy accumulated in the rotating body is converted into electric energy, which passes through each coil. AC power can be supplied to the outside.

  Thus, according to the present embodiment, the rotating body in the vacuum vessel can be functioned by both the flywheel and the rotor of the induction motor / generator, so that a compact structure is achieved by reducing the number of parts. And cost can be reduced.

  Furthermore, in this embodiment, the rotating shaft that rotates the rotating body integrally is supported at both ends in the vacuum vessel, that is, does not protrude outside the vacuum vessel, so consider the sealing structure and the like. And can be supported by a bearing inside the vacuum vessel. Accordingly, not only can the structure be simplified in this respect, but also maintenance can be easily performed.

  According to a second aspect of the present invention, in the flywheel integrated induction motor / generator described in the first aspect, the rotating body is formed by a cage rotor of the induction motor / generator. It is in a flywheel integrated induction motor / generator.

  According to this aspect, since the rotor is a cage rotor of an induction motor / generator, the flywheel integrated induction motor / generator can be efficiently operated.

  According to a third aspect of the present invention, in the flywheel integrated induction motor / generator described in the first or second aspect, the vacuum vessel is formed of an insulator. Located in the motor / generator.

  According to this aspect, since the vacuum vessel is an insulator, eddy currents based on a rotating magnetic field formed by a coil on the surface of the vacuum vessel can be prevented from being generated. As a result, it is possible to contribute to efficient operation of the flywheel integrated induction motor / generator.

  According to a fourth aspect of the present invention, there is provided a flywheel integrated induction motor / generator according to any one of the first to third aspects, wherein the coil is formed of a superconducting coil. It is in a wheel-integrated induction motor / generator.

  According to this aspect, since the coil is formed of a superconducting coil, a large current can flow, and a strong rotating magnetic field having a large magnetic flux density can be easily formed. Therefore, the weight of the rotating body serving as a load in the motor operation mode can be made sufficiently large. On the other hand, in the generator operation mode, high-efficiency power generation can be performed while releasing large mechanical energy accumulated in the rotating body.

  According to the present invention, since the rotating body in the vacuum vessel can be functioned by both the flywheel and the rotor of the induction motor / generator, the structure can be made compact by reducing the number of parts, Cost can be reduced.

  Moreover, since the flywheel and the rotor of the induction motor / generator are also used, both ends of one rotating shaft may be supported rotatably in the vacuum vessel. That is, since the rotating shaft does not protrude outside the vacuum vessel, it can be supported by the bearing inside the vacuum vessel without considering the seal structure or the like. Accordingly, not only can the structure be simplified in this respect, but also maintenance can be easily performed.

It is explanatory drawing which shows typically the cross-sectional shape of the flywheel integrated induction motor / generator which concerns on embodiment of this invention. It is explanatory drawing which shows typically the principal part of the flywheel integrated induction motor and generator which concerns on embodiment of this invention. It is explanatory drawing which shows typically an example of the electric motor and generator with a flywheel concerning a prior art.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory view schematically showing a cross-sectional shape of a flywheel integrated induction motor / generator according to an embodiment of the present invention, and FIG. 2 is an explanatory view schematically showing main parts thereof. As shown in both drawings, the flywheel integrated induction motor / generator I according to the present embodiment is arranged at equal intervals around the rotary body 1 and the vacuum container 3 housed in the vacuum container 3. The three coils 2A, 2B, and 2C are provided.

  The vacuum vessel 3 is formed of an insulating material, for example, FRP, and is coated so as to be processed so that the inside becomes a good vacuum space. In the vacuum container 3 in this embodiment, gas is drawn so that the opening portions at both ends of the cylindrical member are closed with disk-shaped lid members 3A and 3B so that the inside becomes less than atmospheric pressure. However, the vacuum space in the present invention includes not only a space whose pressure is lower than the atmospheric pressure, but also a space that is substantially the same as the atmospheric pressure when filled with a gas having a mass smaller than that of air, such as hydrogen or helium. This is because even in this case, the windage loss is reduced to the same extent as in the vacuum state.

  In addition, bearings 4A and 4B that can be suitably configured by superconducting magnetic bearings or the like are disposed inside the lid members 3A and 3B, and the rotating body 1 is integrally fixed to the bearings 4A and 4B. Both ends of the rotating shaft 7 are rotatably supported. Thus, the rotating body 1 rotates integrally with the rotating shaft 7 inside the vacuum vessel 3. Here, the rotator 1 is formed of a cage rotor of an induction motor / generator so that an eddy current is generated by a rotating magnetic field formed by the coils 2A to 2C. That is, the rotating body 1 is provided with a plurality of conductor rods 5 (12 in FIG. 1) parallel to the rotation shaft 7 in the circumferential direction on the circumferential surface of a cylindrical rotor core, and each conductor rod. 5, the conductor rods 5 adjacent to each other in the circumferential direction are short-circuited by the short-circuit ring 6. As will be described in detail later, since the rotating body 1 in this embodiment also has the function of a flywheel in addition to the function of the rotor of the induction motor, more mechanical energy can be accumulated by rotation. Thus, it is important to configure as a predetermined heavy object. In addition, the coils 2A to 2C in this embodiment are formed of superconducting coils. Therefore, a large current can flow through the coils 2A to 2C, and a strong rotating magnetic field having a large magnetic flux density can be easily formed. Therefore, the weight of the rotating body 1 serving as a load in the motor operation mode can be made sufficiently large. At the same time, in the generator operation mode, high-efficiency power generation can be performed while releasing large mechanical energy accumulated in the rotating body. It can be carried out.

  In this embodiment, when a three-phase AC power is supplied to the coils 2A, 2B, and 2C, a rotating magnetic field that rotates along the circumferential direction of the vacuum vessel 3 is formed. As a result, in the rotating body 1 accommodated in the vacuum vessel 3, eddy current flows through each conductor rod 5 and the short-circuit ring 6, and the magnetic field generated by the eddy current and the rotating magnetic field formed by the coils 2A to 2C As a result, a rotational torque is generated in the rotating body. With this rotational torque, the rotating body 1 is rotationally driven as a rotor of the induction motor by a positive slip s (> 0). By such rotational driving, kinetic energy is accumulated in the rotating body 1.

  On the other hand, when the slip s of the rotating body 1 becomes negative (<0), an induction generator is formed by the coils 2A to 2C and the rotating body 1, and the mechanical energy accumulated in the rotating body is converted into electric energy, and each coil Three-phase AC power can be supplied to the outside via 2A to 2C.

  As described above, according to this embodiment, the rotating body 1 in the vacuum vessel 3 can be functioned by both the flywheel and the rotor of the induction motor / generator, so that the compact structure by reducing the number of parts and The cost can be reduced.

  Furthermore, in this embodiment, the rotating shaft 7 that rotates the rotating body 1 integrally is supported at both ends in the vacuum vessel 3, that is, does not protrude outside the vacuum vessel 3, so that a sealing structure or the like is provided. Can be supported by the bearings 4A and 4B inside the vacuum vessel 3. Accordingly, not only can the structure be simplified in this respect, but also maintenance can be easily performed.

  In the above embodiment, the rotating body 1 is formed by a cage rotor of an induction motor / generator, but is not limited thereto. It suffices that at least a part of the conductor is an eddy current circuit. For example, a rotating body having a double cylinder structure in which the surface of an insulating cylinder is covered with a conductor may be used. In this case, the rotating body in the present invention also has a function of accumulating mechanical energy, so it is desirable to form it with a heavy object. In the case where the rotating body is a squirrel-cage rotor as in the above embodiment, an eddy current caused by a rotating magnetic field can be flowed efficiently, so that the effect of improving the overall efficiency can be obtained.

  The vacuum vessel 3 is desirably an insulator such as FRP or a material combining FRP and graphite, but is not limited thereto. However, when formed of a conductor, an eddy current flows, which causes a reduction in efficiency, but in the case of an insulator, there is no such concern.

  Furthermore, although it is not essential to form the coils 2A to 2C with a superconducting coil, a strong rotating magnetic field having a large magnetic flux density can be easily formed in the case of a superconducting coil. Further, although it is not essential to form the bearing with a superconducting magnetic bearing, when a superconducting magnetic bearing is used, the mechanical friction loss at the bearing portion of the rotating body 1 can be satisfactorily reduced. Incidentally, in the present invention, since the rotating shaft 7 does not penetrate the vacuum vessel 3, the superconducting magnetic bearing can be arranged in a predetermined manner without affecting the vacuum state of the vacuum vessel 3.

  Further, the number of coils 2A to 2C in the above embodiment is set to three in consideration of the case where a three-phase alternating current is used. This is because a rotating magnetic field can be generated even in four phases and five phases.

  INDUSTRIAL APPLICABILITY The present invention can be effectively used in an industrial field in which electric power is efficiently stored as mechanical energy and a system that efficiently converts the stored mechanical energy into electric energy is constructed.

I Flywheel integrated induction motor / generator 1 Rotating body 2A, 2B, 2C Coil 3 Vacuum container 4A, 4B Bearing 5 Conductor bar 6 Short-circuit ring 7 Rotating shaft

Claims (4)

A cylindrical vacuum container that forms a sealed space held in a vacuum;
A rotating shaft having both ends rotatably supported by the vacuum vessel via a bearing;
A rotating body that is formed of a conductor that forms a closed circuit through which eddy current can flow, is fixed to the rotating shaft, and is configured to rotate integrally with the rotating shaft;
A flywheel integrated induction motor / generator having three or more coils arranged at equal intervals around the outside of the vacuum vessel. In the flywheel integrated induction motor / generator according to claim 1,
The flywheel-integrated induction motor / generator, wherein the rotor is a cage rotor of an induction motor / generator. In the flywheel integrated induction motor / generator according to claim 1 or 2,
The said vacuum vessel was formed with the insulator, The flywheel integrated induction motor and generator characterized by the above-mentioned. In the flywheel integrated induction motor / generator according to any one of claims 1 to 3,
The flywheel integrated induction motor / generator, wherein the coil is formed of a superconducting coil.

Images