A high-temperature superconducting flywheel energy storage device including a disconnectable magnetic coupling

Abstract

The present invention provides a high-temperature superconducting flywheel energy storage device including a switchable magnetic coupling, wherein the switchable magnetic coupling includes a magnetic switching device for controlling the clutch state, a permanent magnetic disk and a conductor disk. The magnetic switching device is located between the permanent magnetic disk and the generator or motor. The magnetic switching device is parallel to the permanent magnetic disk and the conductor disk of the magnetic coupling, and is coaxial and cocentric. The center of the magnetic switching device is opened, and the shaft of the generator or motor passes through it. The servo motor is connected to the fixed platform on one side of the magnetic switching device through a lead screw to control the position of the magnetic switching device in the vertical direction, thereby controlling the working state of the switchable magnetic coupling device. The magnetic switching device only moves in the axial direction and does not rotate. Axial guide rails are installed around the magnetic switching device. The present invention can reduce the energy loss in the energy retention stage of the flywheel energy storage system, improve the system efficiency, and help the high-temperature superconducting flywheel energy storage system to store energy for a long time.

Description

Technical Field

[0001] The invention belongs to the field of physical energy storage, and in particular relates to a high-temperature superconducting flywheel energy storage device comprising a disconnectable magnetic coupler. Background Art

[0002] The superconducting flywheel energy storage system generally adopts a structure in which superconducting bearings, flywheels and motors are integrated and placed in a vacuum chamber. The use of superconducting magnetic bearings eliminates mechanical losses, and the vacuum environment eliminates wind resistance. However, the integrated structure makes the flywheel and motor still connected during the energy retention phase of the system, and the no-load loss of the motor causes the energy to not be stored for a long time. Therefore, it is proposed to use a disconnectable magnetic drive technology to connect the flywheel and the motor. During the energy storage or discharge phase, the magnetic coupler is responsible for transmitting torque. During the energy retention phase, a magnetic disconnecting device is used to cut off the torque transmission. The motor will no longer rotate with the flywheel, thereby eliminating the no-load loss of the motor and realizing long-term energy storage of the system. In addition, since the magnetic drive technology has the characteristic of transmitting torque without a real shaft, the motor can be placed outside the vacuum chamber, reducing the water cooling system required by the original structure, which can further improve the system efficiency.

[0003] As the key to eliminating the no-load loss of the motor during the energy retention phase, improving the overall efficiency of the system, and realizing long-term energy storage, the switchable magnetic drive technology should have the following characteristics: (1) high transmission efficiency. Since the magnetic drive transmission efficiency is negatively correlated with the air volume, the switch device should not occupy the air volume space between the permanent magnetic disk and the conductor disk; (2) fast switching capability; (3) easy switching action.

[0004] At present, the literature jointly published by the Tokyo Railway Technology Research Institute, the Superconducting Technology Research Laboratory and other institutions in Japan mentioned a high-temperature superconducting flywheel energy storage system using a non-contact permanent magnetic coupling. The system uses a magnetic coupling for torque transmission between the motor and the flywheel. The magnetic coupling adopts a double permanent magnetic disk structure and uses the repulsion and attraction between permanent magnets to generate torque, but the magnetic coupling used does not have a magnetic breaking function.

[0005] Chinese invention patent CN101719699B uses a permanent magnetic coupling, i.e. a magnetic coupling, to connect the motor shaft and the flywheel main shaft in the flywheel energy storage system to isolate the heat conduction of the motor shaft and prevent the temperature rise of the motor shaft from affecting the stability of the high-temperature superconducting magnetic bearing. However, this patent does not mention whether the motor is placed outside the vacuum chamber, and the magnetic coupling used does not have a torque breaking function.

[0006] Chinese invention patent CN105896878A uses a magnetic coupler with a magnetic breaking function to transfer torque between the motor and the flywheel. Its magnetic breaking device is a superconducting material, and uses the Meissener effect of the superconducting material, i.e., anti-magnetism, to achieve magnetic field decoupling and torque breaking between the active disk and the driven disk. The breaking principle of the present invention is the magnetic circuit shunting method, that is, the low magnetic resistance characteristics of high magnetic permeability materials are used to bypass the magnetic field. In addition, in order to achieve magnetic breaking using the anti-magnetic principle, the magnetic breaking device must be located between the active disk and the driven disk, which will cause the air gap spacing to be too large, thereby affecting the overall efficiency of the system. The magnetic breaking device in the present invention does not occupy the air gap space. In addition, the superconducting material needs a low-temperature environment to enter the Meissener state, and the consumption of refrigeration equipment and cryogenic liquid will bring additional losses to the system. The magnetic breaking device of the present invention can work at room temperature. In addition, the magnetic breaking device in this patent is located in the vacuum chamber, and the cryogenic liquid circulation pipeline needs to pass through the outer wall of the vacuum chamber, which increases the difficulty of manufacturing the vacuum chamber. The magnetic opening device of the present invention is placed outside the vacuum chamber, making the vacuum chamber structure simple and easy to manufacture. In addition, this patent does not mention the magnetization direction of the permanent magnetic disk magnet of the magnetic coupling device, while the permanent magnetic disk of the general magnetic coupling device is axially magnetized. The magnetic coupling device of the present invention adopts a tangential magnetization method.

[0007] Chinese invention patent CN106059248B uses an asynchronous magnetic coupler to transfer torque between the motor and the flywheel, and is equipped with a magnetic disconnecting device. The motor, active disk and magnetic disconnecting device are placed outside the vacuum chamber, and the driven disk is placed inside the vacuum chamber, eliminating the influence of motor heat generation on the stability of the high-temperature superconducting bearing. It does not mention the magnetization direction of the magnet on the permanent magnetic disk in the asynchronous magnetic coupler. The permanent magnet of the conventional magnetic coupler is axially magnetized, but the magnetic circuit of the axially magnetized permanent magnetic disk cannot be completely bypassed from the side of the permanent magnetic disk away from the conductor disk. Therefore, the magnetic disconnecting device has to be located between the conductor disk and the permanent magnetic disk, which will cause the air gap to be too large, thereby affecting the overall efficiency of the system. Summary of the invention

[0008] The present invention is to overcome the energy consumption caused by the no-load loss of the motor in the energy retention stage of high-temperature superconducting flywheel energy storage, and to address the problem of affecting the torque transmission efficiency caused by the existing switchable magnetic drive technology. A high-temperature superconducting flywheel energy storage device including a switchable magnetic coupler is proposed. The present invention can not only eliminate the no-load loss of the motor in the energy retention stage, but also because the magnetic disconnecting device is not between the permanent magnetic disk of the magnetic coupler and the conductor disk of the magnetic coupler, the magnetic coupler breath spacing will not be forced to increase due to the addition of the magnetic start device, which can reduce energy loss, improve system efficiency, and help the high-temperature superconducting flywheel energy storage system to store energy for a long time.

[0009] The present invention adopts a permanent magnetic disk with tangential magnetization, and the magnetization directions of two adjacent magnets are opposite, namely clockwise and counterclockwise, and an iron yoke is filled between the adjacent magnets, and the magnetic lines of force are distributed along the axial direction through the iron yoke between the permanent magnets. This distribution characteristic of the magnetic lines of force allows the magnetic circuit to bypass between the permanent magnetic disk and the conductor disk or bypass from the side of the permanent magnetic disk away from the conductor disk.

[0010] The present invention utilizes the low magnetic resistance characteristics of high magnetic permeability materials to bypass the magnetic field of the permanent magnet, thereby blocking the magnetic field coupling between the permanent magnetic disk and the conductor disk of the magnetic coupler and blocking the transmission of torque between the motor and the flywheel.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] A high-temperature superconducting flywheel energy storage device including a switchable magnetic coupler comprises a generator or a motor, a magnetic disconnecting device, a magnetic coupler permanent magnetic disk, a magnetic coupler conductor disk, a flywheel main shaft, a vacuum chamber and a servo motor system; the flywheel energy storage device is vertically installed, the generator or the motor is located at the uppermost end, the shaft end of the generator or the motor is connected to the magnetic coupler permanent magnetic disk, the magnetic disconnecting device is located between the generator or the motor and the magnetic coupler permanent magnetic disk, the generator or the motor, the magnetic disconnecting device and the magnetic coupler permanent magnetic disk are located outside the vacuum chamber; the magnetic coupler conductor disk and the flywheel main shaft are located inside the vacuum chamber; the lower end surface of the magnetic coupler conductor disk is fixedly connected to the flywheel main shaft; the magnetic disconnecting device comprises an annular high magnetic permeability material, a servo motor system, a lead screw and a fixed platform.

[0013] Furthermore, the permanent magnetic disk of the magnetic coupler includes a permanent magnetic rotor and a conductor rotor. The permanent magnetic rotor is composed of permanent magnets and iron yokes. The permanent magnets and the iron yokes are arranged alternately. The permanent magnets are magnetized tangentially, and the magnetization directions of two adjacent permanent magnets are opposite, namely clockwise and counterclockwise. Finally, the magnetic lines of force are distributed axially through the iron yokes between the permanent magnets.

[0014] Furthermore, the conductor disk of the magnetic coupler is composed of a metal conductor and an iron yoke; the metal conductor has good electrical conductivity, and the iron yoke of the conductor disk of the magnetic coupler is located on a side of the metal conductor away from the permanent magnet disk of the magnetic coupler.

[0015] Furthermore, the magnetic disconnecting device is made of a ring-shaped high-permeability material with a central opening, and is located on the side of the permanent magnetic disk of the magnetic coupler away from the conductor disk of the magnetic coupler, parallel to the permanent magnetic disk of the magnetic coupler and the conductor disk of the magnetic coupler, coaxial and cocentric; the magnetic disconnecting device is connected to the servo motor through a screw rod, and only moves axially without rotational movement, and the clutch state of the magnetic coupler is determined by adjusting the axial position. Axial guide rails are installed around the magnetic disconnecting device to ensure that it always remains parallel to the permanent magnetic disk of the magnetic coupler during the servo motor dragging process.

[0016] Beneficial effects:

[0017] The present invention utilizes the low magnetic resistance characteristics of high magnetic permeability materials to provide a magnetic flux shortcut for the magnetic field, thereby bypassing the magnetic field. The servo motor controls the high magnetic permeability material ring to move away from or close to the permanent magnetic disk of the magnetic coupler to open or close the magnetic flux path between the permanent magnetic disk and the conductor disk, thereby realizing the conversion of the clutch state of the motor and the flywheel main shaft. The device has a simple structure and can be realized through automatic control. It is suitable for radial or axial high-temperature superconducting flywheel energy storage systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic structural diagram of a high-temperature superconducting flywheel energy storage device including a disconnectable magnetic coupling according to the present invention;

[0019] Figure 2 It is a top view of the permanent magnetic disk of the open-ended magnetic coupler;

[0020] Figure 3a It is a front view of the torque transmission state of the magnetic coupling device;

[0021] Figure 3b This is a front view of the torque-breaking state of the magnetic coupling device. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] like Figure 1As shown, a high-temperature superconducting flywheel energy storage device including a switchable magnetic coupler of the present invention comprises a generator or motor 1, a magnetic disconnecting device 2, a magnetic coupler permanent magnetic disk 3, a magnetic coupler conductor disk 4, a flywheel main shaft 5, a vacuum chamber 6, and a servo motor system 7. The flywheel energy storage device is installed vertically, the generator or motor 1 is located at the uppermost end, the shaft end of the generator or motor 1 is connected to the magnetic coupler permanent magnetic disk 3, the magnetic disconnecting device 2 is located between the generator or motor 1 and the magnetic coupler permanent magnetic disk 3, and the generator or motor 1, the magnetic disconnecting device 2 and the magnetic coupler permanent magnetic disk 3 are located outside the vacuum chamber 6. The magnetic coupler conductor disk 4, the flywheel main shaft 5, etc. are located inside the vacuum chamber 6. The magnetic disconnecting device 2 can adjust the axial position through the servo motor system 7. The magnetic coupler conductor disk 4, the flywheel and the flywheel main shaft 5, and the superconducting magnetic bearing are all located in the vacuum chamber 6. The magnetic breaking device 2, the magnetic coupler permanent magnetic disk 3, and the magnetic coupler conductor disk 4 are coaxial and concentric. A gap is reserved between the magnetic coupler permanent magnetic disk 3 and the top wall of the vacuum chamber 6. The lower end surface of the magnetic coupler conductor disk 4 is fixedly connected to the flywheel main shaft 5. The flywheel and the superconducting magnetic bearing are located below the magnetic coupler conductor disk 4.

[0024] The magnetic breaking device 2 comprises a high magnetic conductivity material ring, a fixing bracket, a motor system and a lead screw.

[0025] The high magnetic permeability material ring is made of high magnetic permeability materials such as iron-nickel alloy, silicon steel sheet or Permalloy with a nickel content of 76% to 86%.

[0026] The magnetic breaking device 2 is provided with axial guide rails around it to ensure that it is always kept parallel to the permanent magnetic disk 3 of the magnetic coupling during the servo motor driving process.

[0027] like Figure 2 As shown, the permanent magnetic disk 3 of the magnetic coupler of the present invention is composed of a permanent magnet 10 and an iron yoke 11. The permanent magnet 10 is tangentially magnetized, and the magnetization directions of two adjacent permanent magnets 10 are opposite, namely clockwise and counterclockwise.

[0028] The magnetic breaking device 2 of the present invention further comprises a fixed platform 9, which is connected to the magnetic breaking device 2 and the lead screw 8 and can perform linear motion in the axial direction.

[0029] The servo motor system 7 includes a medium-speed motor and an integrated automatic control system, which can control the motor to rotate forward or reversely through a remote control or remote control device, and the motor shaft end is connected to a lead screw 8. The lead screw 8 is made of metal material and is connected to a fixed platform 9.

[0030] like Figure 3a , Figure 3bAs shown, when the flywheel energy storage device is in a charging state, the servo motor is controlled to reverse through a remote control or remote control device, and the servo motor shaft end is connected to the lead screw 8 to drive the high magnetic permeability material ring, that is, the magnetic decoupling device, away from the magnetic coupler permanent magnetic disk 3, that is, the magnetic coupling device is in a torque transmission state, and the magnetic field generated by the magnetic coupler permanent magnetic disk 3 can pass through the vacuum chamber 6 to form a magnetic coupling with the magnetic coupler conductor disk 4, and the magnetic coupler transmits torque normally; when the flywheel energy storage state is converted to the energy retention state, the motor is controlled to rotate forward through the remote control or remote control device, and the servo motor shaft end is connected to the lead screw 8 to drive the high magnetic permeability material ring. The material ring, i.e., the magnetic decoupling device, is close to the permanent magnetic disk 3 of the magnetic coupler. At this time, the low magnetic resistance characteristics of the high magnetic permeability material ring are used to provide a magnetic bypass path for the magnetic field of the permanent magnetic disk 3 of the magnetic coupler, i.e., the magnetic coupling device is in a torque-off state, and the magnetic field generated by the permanent magnetic disk 3 of the magnetic coupler cannot reach the conductor disk 4 of the magnetic coupler, thereby blocking the magnetic coupling between the permanent magnetic disk of the magnetic coupler and the conductor disk of the magnetic coupler, i.e., blocking the torque transmission between the two, achieving complete separation of the motor and the flywheel main shaft 5, stopping the motor, eliminating the no-load loss of the motor in the energy retention stage, and improving the system operation efficiency.

[0031] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high temperature superconducting flywheel energy storage device including a disconnectable magnetic coupling, characterized in that: The flywheel energy storage device comprises a generator or a motor (1), a magnetic disconnecting device (2), a magnetic coupling permanent magnetic disk (3), a magnetic coupling conductor disk (4), a flywheel main shaft (5), a vacuum chamber (6) and a servo motor system (7); the flywheel energy storage device is vertically installed, the generator or the motor (1) is located at the uppermost end, the shaft end of the generator or the motor (1) is connected to the magnetic coupling permanent magnetic disk (3), the magnetic disconnecting device (2) is located between the generator or the motor (1) and the magnetic coupling permanent magnetic disk (3), and the generator or the motor (1) , the magnetic breaking device (2) and the magnetic coupling permanent magnetic disk (3) are located outside the vacuum chamber (6); the magnetic coupling conductor disk (4) and the flywheel main shaft (5) are located inside the vacuum chamber (6); the magnetic breaking device (2) is parallel to the end faces of the magnetic coupling permanent magnetic disk (3) and the magnetic coupling conductor disk (4), and is coaxial and concentric; the lower end face of the magnetic coupling conductor disk (4) is fixedly connected to the flywheel main shaft (5); the magnetic breaking device (2) comprises a high magnetic permeability material ring, a servo motor system (7), a lead screw (8) and a fixed platform (9); The magnetic coupling device permanent magnetic disk (3) is composed of a permanent magnet and an iron yoke, the permanent magnet and the iron yoke are arranged alternately, the permanent magnet is magnetized tangentially, and the magnetization directions of two adjacent permanent magnets are opposite, namely clockwise and counterclockwise respectively; finally, the magnetic lines of force are distributed axially through the iron yoke between the permanent magnets, and the low magnetic resistance characteristics of the high magnetic permeability material ring are used to provide a magnetic bypass path for the magnetic field of the magnetic coupling device permanent magnetic disk.

2. A high temperature superconducting flywheel energy storage device comprising a disconnectable magnetic coupling according to claim 1, characterized in that: The magnetic coupler conductor disk (4) is composed of a metal conductor and an iron yoke; the metal conductor has good electrical conductivity, and the iron yoke of the magnetic coupler conductor disk (4) is located on a side of the metal conductor away from the magnetic coupler permanent magnet disk (3).

3. A high temperature superconducting flywheel energy storage device comprising a disconnectable magnetic coupling according to claim 1, characterized in that: The magnetic breaking device (2) comprises a high magnetic conductivity material ring with a central opening, which is located on the side of the magnetic coupler permanent magnetic disk away from the magnetic coupler conductor disk, parallel to the magnetic coupler permanent magnetic disk and the magnetic coupler conductor disk, and coaxial and cocentric.

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