A magnetic levitation flywheel energy storage device that shares axial magnetic flux between a motor and a magnetic bearing system

Abstract

The present invention discloses a magnetic levitation flywheel energy storage device that shares axial magnetic flux with a motor and a magnetic bearing system. The stationary portion of the five-degree-of-freedom magnetic bearing comprises "pole shoe"-type radial magnetic poles and a "pole shoe"-type torsional stator, each of which is wound with coils. The rotating portion of the five-degree-of-freedom magnetic bearing comprises a radial receiving ring, a torsional receiving ring, a radial bias magnetic flux receiving ring, a gyroscope-shaped flywheel, and a first repulsive permanent magnet ring. The flywheel is suspended in the middle of an outer shell, and the three receiving rings are embedded in the outer wall of the flywheel. The first repulsive permanent magnet ring is embedded in the bottom of the flywheel; the second repulsive permanent magnet ring is embedded in a groove at the bottom of the outer shell and is coaxially arranged opposite the first repulsive permanent magnet ring. Two contacting embedded permanent magnet blocks are vertically and horizontally arranged on the inner side of the upper portion of the flywheel. The axial flux motor adopts a single stator and single rotor structure. The present invention can balance system integration, energy storage performance, system loss, safety and stability, and cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic levitation flywheels, and in particular relates to a magnetic levitation flywheel energy storage device that shares axial magnetic flux between a motor and a magnetic bearing system. Background Art

[0002] The magnetic levitation flywheel energy storage device (flywheel battery) breaks through the limitations of chemical batteries and uses physical methods to achieve energy storage. It has the characteristics of large charging and discharging current and short time, good environmental adaptability, high energy conversion efficiency, and long cycle life. The magnetic levitation flywheel energy storage device (flywheel battery) is mainly composed of a flywheel, radial magnetic bearings, axial magnetic bearings, torsional magnetic bearings, auxiliary bearings, and electric / generators. At present, the magnetic flux of the magnetic levitation system and the magnetic flux of the motor in most magnetic levitation flywheel energy storage devices are separated, and the energy storage performance and safety and stability of the existing magnetic bearing system are not very high. The specific problems are as follows:

[0003] The mainstream structural topology of traditional flywheel energy storage devices usually has a long inertial main shaft, and key components such as magnetic bearings, flywheels, and motors are arranged around the inertial main shaft. The motor system and the magnetic levitation system are independent. Therefore, the integration level of this type of structure is low and it is only suitable for some occasions where the axial space is not restricted. Furthermore, a type of "bearingless" motor that integrates radial magnetic bearings with motors installs the windings that generate radial force in the magnetic bearings on the motor stator, thereby reducing the number of radial magnetic bearings arranged axially around the inertial main shaft. As for axial magnetic bearings, due to the heavy weight of the flywheel, the number of permanent magnets used in the magnetic bearings is large, resulting in large losses.

[0004] To improve energy storage performance, the choice of flywheel material is crucial. Existing technologies primarily include metal and composite materials. While metal reduces cost, it also reduces tensile strength, limiting the flywheel's maximum speed. Increasing energy storage performance requires a significant increase in flywheel weight and volume, compromising safety. Composite materials, while offering excellent tensile strength and safety, are more expensive. Therefore, a balance must be struck between flywheel material quality, safety, and cost.

[0005] In terms of safety performance, the topological shape of the flywheel largely determines the safety performance of the system. If the topological shape of the flywheel is not designed appropriately, it will seriously affect the safety performance of the system.

[0006] In summary, in the prior art, it is difficult to achieve an effective balance when weighing various performance characteristics when designing a flywheel energy storage device. Summary of the Invention

[0007] In view of the deficiencies in the prior art, the present invention provides a magnetic levitation flywheel energy storage device that shares the axial magnetic flux of a motor and a magnetic bearing system.

[0008] The present invention achieves the above technical objectives through the following technical means.

[0009] A magnetic levitation flywheel energy storage device that shares axial magnetic flux between a motor and a magnetic bearing system, comprising a five-degree-of-freedom magnetic bearing and an axial flux motor coaxially distributed inside a cylindrical housing;

[0010] The five-degree-of-freedom magnetic bearing includes a stationary part and a rotating part; the stationary part includes a "pole shoe" type radial magnetic pole, a "pole shoe" type torsion stator, a radial control coil, a torsion coil and a magnetic bearing axial coil; the "pole shoe" type radial magnetic pole and the "pole shoe" type torsion stator are fixed inside the cylindrical shell from top to bottom, and the radial control coil is wound on the "pole shoe" type radial magnetic pole, and the torsion coil is wound on the "pole shoe" type torsion stator, wherein the number of the "pole shoe" type radial magnetic pole and the "pole shoe" type torsion stator is a multiple of 3; the rotating part includes a radial receiving ring, a torsion receiving ring, a radial bias magnetic flux receiving ring, a gyroscope-shaped flywheel, and a first repulsive permanent magnet ring, the flywheel is suspended in the middle of the cylindrical shell, the radial receiving ring, the torsion receiving ring, and the radial bias magnetic flux receiving ring are embedded in the outer wall of the flywheel, and the first repulsive permanent magnet ring is embedded in the bottom of the flywheel;

[0011] A second repulsive permanent magnet ring is coaxially arranged opposite to the first repulsive permanent magnet ring, and the second repulsive permanent magnet ring is embedded in a groove at the bottom of the cylindrical shell; a first embedded permanent magnet block is vertically arranged on the inner side of the upper portion of the flywheel, and a second embedded permanent magnet block is horizontally arranged, and the first embedded permanent magnet block is located above the second embedded permanent magnet block, and the two are in contact;

[0012] The axial flux motor is located in a groove on the upper part of the flywheel, and includes an axial flux motor main shaft, a motor stator, a motor rotor, a magnetically conductive ferrite and a permanent magnet. The axial flux motor main shaft is placed at the upper end of the through hole in the middle of the flywheel, the motor stator is located above the motor rotor and is coaxially arranged on the axial flux motor main shaft. A permanent magnet is fixed on the motor rotor, and the permanent magnet is embedded in the flywheel; the magnetically conductive ferrite is embedded in the bottom of the groove; the motor stator and the axial coil of the magnetic bearing are coaxially arranged;

[0013] At the lower end of the through hole, a virtual main shaft is arranged coaxially with the main shaft of the axial flux motor, and the virtual main shaft is connected to the bottom of the cylindrical shell.

[0014] In the above technical solution, the number of the first embedded permanent magnet blocks and the second embedded permanent magnet blocks are both even, and two adjacent ones form a group; when there is only one group of the first embedded permanent magnet blocks and the second embedded permanent magnet blocks, no magnetic isolation aluminum block is provided; if the number of groups of the first embedded permanent magnet blocks and the second embedded permanent magnet blocks is greater than or equal to 2, a magnetic isolation aluminum block is provided between each group.

[0015] In the above technical solution, the flywheel is thick at the top and thin at the bottom, has a disc-shaped bottom, and the main body is made of carbon fiber material.

[0016] In the above technical solution, an odd number of radial bias magnetic flux receiving rings are arranged at intervals on the outer side of the upper part of the flywheel, an odd number of radial receiving rings are arranged at intervals on the outer side of the flywheel below the radial bias magnetic flux receiving rings, and an odd number of torsion receiving rings are arranged at intervals on the outer side of the lower part of the flywheel; the radial receiving rings, torsion receiving rings and radial bias magnetic flux receiving rings are arranged coaxially.

[0017] In the above technical solution, receiving rings are also provided on the cylindrical shells corresponding to the radial receiving ring, the torsion receiving ring and the radial bias magnetic flux receiving ring, and all the receiving rings are made of metal material.

[0018] In the above technical solution, the portion of the “pole shoe” type radial magnetic pole close to the radial receiving ring and the portion of the “pole shoe” type torsional stator close to the torsional receiving ring are both arc-shaped.

[0019] In the above technical solution, the magnetic pole thickness of the "pole shoe" type torsion stator is smaller than the magnetic pole thickness of the "pole shoe" type radial pole.

[0020] In the above technical solution, a layer of sound insulation cotton is installed on the inner surface of the cylindrical shell.

[0021] In the above technical solution, the cylindrical shell is tightly fixed to the upper end cover, the edge of the upper end cover is provided with heat dissipation holes, second heat dissipation holes are opened on both sides and the bottom of the cylindrical shell, and the outer side of the cylindrical shell is also fixed with a fin-shaped heat dissipation wing.

[0022] In the above technical solution, the number of the "pole shoe" type radial magnetic poles and the "pole shoe" type torsional stators are both 6, and two adjacent ones are regarded as one phase, which is divided into three phases A, B, and C. Current is passed through the coils on each phase at intervals.

[0023] The beneficial effects of the present invention compared to the prior art are:

[0024] (1) The magnetic levitation flywheel energy storage device of the present invention, which shares the axial magnetic flux of the motor and the magnetic bearing system, balances the performance characteristics of the system, such as system integration, energy storage performance, system loss, safety and stability, and cost.

[0025] (2) The present invention proposes a concept of sharing axial magnetic flux between the flywheel and the motor. The motor adopts an improved axial magnetic flux motor, rationally utilizes the unbalanced magnetic pull, and allows the unbalanced magnetic pull to serve as the axial suspension force of the flywheel. Axial suspension can also be achieved without the need for axial permanent magnets.

[0026] (3) The flywheel of the present invention adopts a shape similar to a gyroscope, and utilizes the high stability of the gyroscope when it rotates to improve the stability of the flywheel when it rotates.

[0027] (4) The present invention adopts "pole shoe" type radial magnetic poles and "pole shoe" type torsional stators to reduce the air gap magnetic resistance and improve the magnetic field distribution of the main magnetic pole; it can help control the magnetic flux better and better improve the safety and stability of the system.

[0028] (5) The "pole shoe" type radial magnetic poles and the "pole shoe" type torsional stator of the present invention are preferably 6 in number, and two adjacent ones are regarded as one phase, which are divided into three phases A, B, and C. Current is passed through the coils of each phase at intervals to provide a closed loop for the magnetic field generated by the short-circuited winding, thereby avoiding magnetic coupling.

[0029] (6) The design of the virtual main shaft of the present invention embeds the axial flux motor part into the flywheel on this basis, which not only can share the axial flux of the motor with the magnetic bearing system, but also greatly improves the axial integration; in addition, the embedded permanent magnet block and the magnetic isolation aluminum block are all embedded in the flywheel, which greatly improves the radial integration.

[0030] (7) The flywheel of the present invention is made of a composite of metal material and carbon fiber material, which not only ensures safety but also effectively reduces costs.

[0031] (8) The outer side of the shell and the end cover of the present invention are provided with heat dissipation holes, which can also be used for wiring; the inside of the shell is paved with strong sound insulation cotton, which can better prevent the spread of noise. When danger occurs, it can also alleviate the situation where the flywheel hits the shell and causes serious breakage as much as possible.

[0032] (9) The bottom of the housing and the bottom of the flywheel of the present invention use the same repulsive permanent magnet ring, which can better achieve axial suspension (the magnetic flux of the axial flux motor alone may not be stable enough), ensuring the safety and stability of the system during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a cross-sectional view of the overall structure of the present invention;

[0034] Figure 2 It is a top view of the overall structure of the present invention;

[0035] Figure 3 It is a cross-sectional view of the overall structure of the present invention from another perspective;

[0036] Figure 4 yes Figure 1 Cross-sectional view of the flywheel structure;

[0037] Figure 5 It is an enlarged structural diagram of the motor in the present invention;

[0038] Figure 6 It is the assembly diagram of the "pole shoe" type radial magnetic pole and the "pole shoe" type torsional stator;

[0039] Figure 7 It is the schematic diagram of realizing the radial control magnetic circuit during the operation of the present invention;

[0040] Figure 8 It is the schematic diagram of realizing the radial bias magnetic circuit during the operation of the present invention;

[0041] Figure 9 It is the schematic diagram of the bias magnetic circuit shared by the axial magnetic flux of the axial flux motor and the magnetic bearing system during the operation of the present invention;

[0042] Figure 10 It is the schematic diagram of realizing the torsion control magnetic circuit during the operation of the present invention;

[0043] In the figure: 1. Upper end cover; 11. First heat dissipation hole; 21. Cylindrical outer shell; 22. Second heat dissipation hole; 23. Fin-shaped heat dissipation wing; 31. "Pole shoe" type radial magnetic pole; 32. Radial control coil; 41. "Pole shoe" type torsion stator; 42. Torsion coil; 5. Flywheel; 51. First embedded permanent magnet block; 52. Second embedded permanent magnet block; 53. First magnetic isolation aluminum block; 54. Second magnetic isolation aluminum block; 61. First repulsive permanent magnet ring; 62. Second repulsive permanent magnet ring; 71. Axial flux motor main shaft; 72. Motor stator; 73. Magnetic bearing axial coil; 74. Motor rotor; 75. Magnetoferrite; 76. Groove; 77. Permanent magnet; 8. Virtual main shaft; 91. Radial receiving ring; 92. Torsion receiving ring; 93. Radial bias magnetic flux receiving ring, 10. Through hole. Specific embodiments

[0044] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0045] As Figure 1 、 2 、3 shown, the outermost part of a magnetic levitation flywheel energy storage device with shared axial magnetic flux of a motor and a magnetic bearing system of the present invention is a hollow-structured cylindrical outer shell 21, and the upper end of the cylindrical outer shell 21 is tightly fixed with an upper end cover 1; inside the cylindrical outer shell 21, a "pole shoe" type radial magnetic pole 31 and a "pole shoe" type torsion stator 41 are fixed from top to bottom. A radial control coil 32 is wound on the "pole shoe" type radial magnetic pole 31, and a torsion coil 42 is wound on the "pole shoe" type torsion stator 41. The number of the "pole shoe" type radial magnetic poles 31 and the "pole shoe" type torsion stators 41 is a multiple of 3, and 6 is preferably selected in this embodiment (further refer to Figure 6The flywheel 5 is suspended in the middle of the cylindrical housing 21. A first embedded permanent magnet block 51 is vertically positioned on the inner side of the upper portion of the flywheel 5, while a second embedded permanent magnet block 52 is horizontally positioned. The first embedded permanent magnet block 51 is positioned above the second embedded permanent magnet block 52, and the two are in contact. The upper end cap 1 is disc-shaped with heat dissipation holes 11 on its edge. These holes are used not only for heat dissipation but also for wiring. Second heat dissipation holes 22 are provided on both sides and the bottom of the cylindrical housing 21. Also fixed to the outside of the cylindrical housing 21 are fin-shaped heat dissipation wings 23.

[0046] A five-degree-of-freedom magnetic bearing and an axial flux motor are coaxially distributed within the cylindrical housing 21. The five-degree-of-freedom magnetic bearing comprises a stationary portion and a rotating portion. The stationary portion comprises a "pole shoe" type radial magnetic pole 31, a "pole shoe" type torsion stator 41, a radial control coil 32, a torsion coil 42, and a magnetic bearing axial coil 73. The rotating portion comprises a radial receiving ring 91, a torsion receiving ring 92, a radial bias flux receiving ring 93, a flywheel 5, and a first repulsive permanent magnet ring 61. The radial receiving ring 91, the torsion receiving ring 92, and the radial bias flux receiving ring 93 are embedded in the outer wall of the flywheel 5, and the first repulsive permanent magnet ring 61 is embedded in the bottom of the flywheel 5. A second repulsive permanent magnet ring 62 is coaxially arranged opposite to the first repulsive permanent magnet ring 61 and embedded in a groove at the bottom of the cylindrical housing 21. See. Figure 9 A groove 76 is provided on the upper portion of the flywheel 5. An axial flux motor is placed inside the groove 76, including an axial flux motor shaft 71, a motor stator 72, a motor rotor 74, a permanent magnet 77 and a magnetically conductive ferrite 75. The axial flux motor shaft 71 is placed at the upper end of the through hole 10 in the middle of the flywheel 5 ( Figure 4 ), the motor stator 72 is located above the motor rotor 74 and is coaxially arranged on the axial flux motor main shaft 71. A permanent magnet 77 is fixed to the motor rotor 74, and the permanent magnet 77 is embedded in the flywheel 5, so that the axial flux motor can drive the flywheel 5 to rotate; the motor stator 72 is composed of an A-phase stator, a B-phase stator, and a C-phase stator in a clockwise direction; the conductive ferrite 75 is embedded in the bottom of the groove 76, so that the magnetic flux forms a closed magnetic circuit. The magnetic bearing axial coil 73 and the motor stator 72 are coaxially arranged. The lower part of the through hole 10 is used to accommodate the virtual main shaft 8, which is connected to the bottom of the cylindrical shell 21; the virtual main shaft 8 is coaxial with the axial flux motor main shaft 71.

[0047] See also Figure 4 As shown, the flywheel 5 is shaped like a gyroscope in appearance and is made of a single piece of composite material. It is thick at the top and thin at the bottom, and has a disc-shaped bottom with a circle of grooves for embedding the first repulsive permanent magnet ring 61 .

[0048] The axial flux motor used in the present invention is different from the traditional one. It adopts a single stator and single rotor form. The purpose is to use the unbalanced magnetic pull of the motor as the axial bias flux of the magnetic suspension. Figure 5shown.

[0049] See also Figure 8 、 10 An odd number of radially biased magnetic flux receiving rings 93 are spaced apart on the outer side of the upper portion of the flywheel 5. An odd number of radially biased magnetic flux receiving rings 91 are spaced apart on the outer side of the flywheel 5 below the radially biased magnetic flux receiving rings 93. An odd number of torsion receiving rings 92 are spaced apart on the outer side of the lower portion of the flywheel 5. The inner diameters of these three receiving rings are the same as the outer diameters of the upper and lower portions of the flywheel 5, respectively. The radial receiving rings 91, torsion receiving rings 92, and radially biased magnetic flux receiving rings 93 are coaxially arranged. Receiving rings are also provided on the corresponding housings of the radial receiving rings 91, torsion receiving rings 92, and radially biased magnetic flux receiving rings 93, and all receiving rings are made of metal.

[0050] The radial bias portion of the five-degree-of-freedom magnetic bearing includes: a first embedded permanent magnet block 51 and a second embedded permanent magnet block 52 for generating magnetic flux. The first embedded permanent magnet block 51 and the second embedded permanent magnet block 52 are both an even number, and two adjacent ones form a group. When there is only one group of the first embedded permanent magnet block 51 and the second embedded permanent magnet block 52, the first magnetic isolation aluminum block 53 and the second magnetic isolation aluminum block 54 are not provided. If the number of groups of the first embedded permanent magnet block 51 and the second embedded permanent magnet block 52 is greater than or equal to 2, a magnetic isolation aluminum block is provided between each group for carrying and isolating the magnetic circuit. This embodiment takes 3 groups as an example, see Figure 7 、 8 The first magnetic isolation aluminum block 53 is embedded in the upper part of the flywheel 5. A first magnetic isolation aluminum block 53 is set between two first embedded permanent magnet blocks 5. The second magnetic isolation aluminum block 54 is embedded in the flywheel 5. A second magnetic isolation aluminum block 54 is set between two second embedded permanent magnet blocks 52 to serve as a load and isolate the magnetic circuit. The N pole and S pole distribution of the first embedded permanent magnet block 51 and the second embedded permanent magnet block 52 are shown in FIG. Figure 8 The first embedded permanent magnet block 51 and the second embedded permanent magnet block 52 are in contact inside the flywheel 5. The two first embedded permanent magnet blocks 51 and the two second embedded permanent magnet blocks 52 form a group of radial offsets. The first magnetic isolation aluminum block 53 and the second magnetic isolation aluminum block 54 are used to isolate the magnetic circuit in the middle of each group of radial offsets to prevent the diffusion of magnetic flux.

[0051] The portions of the "pole shoe" radial magnetic poles 31 near the radial receiving ring 91 and the "pole shoe" torsional stators 41 near the torsional receiving ring 92 are both arc-shaped. This arrangement allows for matching the dimensions of the outer periphery of the receiving ring while leaving an air gap for magnetic flux transfer. In this invention, "pole shoe" radial magnetic poles 31 and "pole shoe" torsional stators 41 are designed to reduce the air gap magnetic resistance, improve the main magnetic pole magnetic field distribution, facilitate fixation of the excitation winding, reduce material loss, and increase safety. The expansion of the "pole shoe" torsional stators 41 near one end of the flywheel 5 reduces the air gap magnetic resistance, improves the main magnetic pole magnetic field distribution, and facilitates magnetic flux transfer in conjunction with the receiving ring. The six "pole shoe" radial magnetic poles 31 and the six "pole shoe" torsional stators 41 have the same structure and are distributed along the circumference during installation, with the exterior fixed to the interior of the cylindrical housing 21. The thickness of the "pole shoe" type twisted stator 41 magnetic pole is smaller than that of the "pole shoe" type radial magnetic pole 31, mainly because radial deviation generally occurs more often and twisting occurs slightly less, and such a design can reduce the use of materials.

[0052] In order to improve the overall stability, a layer of high-strength sound insulation cotton is installed on the inner surface of the cylindrical shell 21. The specific assembly is as follows: Figure 1 As shown, the noise is reduced to a certain extent. In addition, the reason why the sound insulation cotton is of higher strength is to prevent accidental collision when the flywheel 5 rotates at high speed.

[0053] When the magnetic levitation flywheel energy storage device of the present invention is in operation, the conversion of electrical energy and mechanical energy is achieved through the rotation of the flywheel 5, which is divided into three stages: charging, energy storage, and discharging.

[0054] (1) In the charging stage, the rotation of the flywheel 5 is achieved by the rotation of the axial flux motor. Specifically, corresponding currents are passed through the windings of the A-phase stator, the B-phase stator, and the C-phase stator in the motor stator 72 to interact with the permanent magnet 77, ensuring that the flywheel can achieve accelerated rotation, achieve the conversion of mechanical energy into electrical energy, and realize the input of electrical energy.

[0055] (2) Energy storage stage: When the input electrical energy is sufficient and the magnetic levitation flywheel energy storage device is in a full state, the axial flux motor keeps idling and the flywheel 5 maintains a constant speed; before the next discharge state, there is no energy exchange in the system.

[0056] (3) Discharge stage: In this stage, the axial flux motor acts as a generator, and the flywheel 5 outputs energy, which is combined with power electronic devices to achieve the conversion between mechanical energy and electrical energy.

[0057] The present invention breaks away from the traditional motor design of the magnetic levitation system. It achieves a flux sharing effect by supplying the axial bias flux of the magnetic levitation system with the axial unbalanced magnetic flux generated by the axial flux motor with a single stator and a single rotor. By designing a flywheel 5 with a gyroscopic topology and rationally utilizing the repulsive force and electromagnetic force, higher-precision control is achieved while simplifying the structure and reducing the thickness. It can meet the static suspension, radial two-degree-of-freedom control, torsional two-degree-of-freedom control, and axial single-degree-of-freedom control of the flywheel 5. At the same time, compared with traditional structures, the present invention can also reduce current loss during control. The specific implementation method is as follows:

[0058] Implementation of axial single degree of freedom control: Figure 9 As shown, since the permanent magnet 77 of the motor rotor 74 is embedded in the flywheel 5, the axial magnetic flux forms a magnetic circuit through the ferrite magnet 75: the N pole of the permanent magnet 77 - the ferrite magnet 75 - the S pole of the permanent magnet 77 - the N pole of the permanent magnet 77 - the S pole of the permanent magnet 77, i.e., the axial magnetic circuit of the axial flux motor. Due to the single rotor and single stator structure, an axial unbalanced magnetic pull can be generated to generate an axial positive pull on the flywheel 5. This pull is offset by the gravity of the flywheel 5 itself, achieving static suspension of the flywheel 5. Compared with the structure of the prior art that uses repulsive force to achieve suspension, the structure of the axial flux motor used in the present invention can achieve axial suspension of the flywheel 5 without using axial permanent magnets. The biggest difference of the present invention lies in this magnetic flux sharing. At the same time, the use of the first repulsive permanent magnet ring 61 and the second repulsive permanent magnet ring 62 also allows the structure to reduce the impact of small disturbances through self-balancing, reducing the loss of the magnetic bearing axial coil 73. Axial control is achieved through the electromagnetic force generated by energizing the axial coil 73 of the magnetic bearing. When it is detected that the flywheel 5 is disturbed in the axial single degree of freedom beyond the allowable range of self-balancing, a control current is passed through the axial coil 73 of the magnetic bearing to return the flywheel 5 to the axial equilibrium position.

[0059] Implementation of radial two-degree-of-freedom control: Figure 7 As shown, for the convenience of introduction, two adjacent ones of the six "pole shoe" type radial magnetic poles 31 are regarded as one phase, which is divided into three phases A, B, and C. One of the magnetic circuits is taken for introduction. Figure 7 、 8 As shown, the magnetic flux of the horizontally arranged second embedded permanent magnet block 52 starts from the N pole, passes through the N pole of the first embedded permanent magnet block 51 perpendicular to the S pole of the second embedded permanent magnet block 52, and is then attracted to the N pole of another first embedded permanent magnet block 51 by the attraction of the N pole. After the same steps as above, it returns to the S pole of the first embedded permanent magnet block 51. Then, it passes through the radial bias flux receiving ring 93, attracting the magnetic flux from the S pole to the N pole, forming a magnetic circuit, that is, the magnetic circuit of the radial bias flux. By applying control current to the six radial control coils 32 at intervals, a magnetic circuit is generated. Figure 7 The control magnetic flux is indicated by the dashed line and arrows. Starting from one pole of the "pole shoe" radial magnetic pole piece 31, the control magnetic flux is divided into two equal paths. These paths pass through the radial receiving ring 91, then through the radial bias magnetic flux receiving ring 93, then through another radial receiving ring 91, and finally through the receiving ring on the outer casing, returning to the starting point, thus forming a complete control magnetic circuit. When the flywheel 5 is subjected to axial disturbances, the coordination of the three-phase radial poles A, B, and C generates a synthetic magnetic pull, achieving radial two-degree-of-freedom control.

[0060] Implementation of torsional two-degree-of-freedom control: Figure 10 As shown, when the flywheel 5 is subjected to a small disturbance and produces a small torsion, current is supplied to the torsion coils 42, forming the following Figure 10 The magnetic circuit shown generates a magnetic pull that returns the flywheel 5 to its equilibrium position. When the torsion angle of the flywheel 5 exceeds the threshold that can be corrected by the embedded permanent magnet block, control is achieved by passing a torsion control current through the six torsion coils 42 at intervals. The control magnetic flux generated by the torsion control current travels through the torsion receiving ring 92 to the next torsion receiving ring 92, then through the "pole shoe" type torsion stator 41, and finally through the receiving ring on the housing, forming a magnetic flux loop. This achieves a control effect, allowing the flywheel 5 to return to a safe and stable position in a timely manner.

[0061] In order to reduce magnetic circuit coupling and improve control accuracy, the present invention uses the new concept of flux sharing in axial suspension. The unbalanced magnetic pull generated by the unbalanced magnetic flux of the axial flux motor with a single stator and a single rotor is used as the axial pull of the flywheel 5 to achieve static suspension of the flywheel 5. The first repulsive permanent magnet ring 61 and the second repulsive permanent magnet ring 62 form a mutually repulsive force, further ensuring the stability of the axial suspension force. In radial control, a "pole shoe" type radial magnetic pole 31 is used, which divides the radial magnetic circuit into two layers, the left and right. The two layers of magnetic circuit work together to increase the stability of the flywheel 5. In addition, the radial line control ring 32 is far away from the torsional coil 42, ensuring that there is no mutual induction between the two.

[0062] On the basis of being able to achieve high control accuracy, the present invention has better energy storage performance and better safety performance while being lightweight, and the implementation method is as follows:

[0063] Achievement of high safety: Compared with the prior art which uses high-performance magnetic steel to ensure magnetic conduction inside the flywheel, the present invention uses the idea of ​​magnetic flux sharing and the idea of ​​repulsive permanent magnet rings in a reasonable manner, so that the magnetic circuit is not entirely set inside the flywheel 5. Therefore, carbon fiber material is used in the main part of the flywheel 5, which ensures that the flywheel 5 has high tensile strength while maintaining dimensional stability and high resistance to deformation, thereby achieving long-term use without deformation. At the same time, carbon fiber material can reduce weight by more than 60% compared to high-performance steel of the same volume. When the flywheel 5 exceeds the critical speed and breaks, the radially ejected fragments first come into contact with the high-strength sound insulation cotton inside the cylindrical shell 2, and the fragments will not easily collide with the cylindrical shell 2. In this process, most of the energy of the fragments has been absorbed by the sound insulation cotton, and then they stop moving after coming into contact with the cylindrical shell 21. The heat dissipation holes and the fin-shaped heat dissipation wings 23 on the cylindrical shell 21 can better ensure the heat dissipation and good operation of the system.

[0064] Achievement of high energy storage performance: The flywheel 5 is mainly made of composite materials and supplemented by metal materials. The carbon fiber material used in large quantities in the flywheel 5 has a very large specific strength (the ratio of maximum axial stress to density). Under the same structure, it has a greater energy storage density, thereby improving the energy storage performance of the flywheel.

[0065] Implementation of low loss: When controlling the balance of the flywheel 5, the present invention adopts the idea of ​​magnetic flux sharing, the joint action of repulsion and electromagnetic force. When the flywheel 5 is working, the position of the flywheel 5 is compared with the equilibrium position. When the axial deviation and rotational deviation of the flywheel 5 are lower than the set threshold, it is determined that the axial and torsional disturbances are relatively small at this time, and the self-balancing effect can be achieved through the action between the repulsive permanent magnet rings, thereby reducing the loss of the control current.

[0066] Low-cost implementation: The concept of axial flux sharing significantly reduces the number of permanent magnets required for axial bias flux, while the design of the radial control coil reduces coil material loss. During axial suspension, the enhanced magnetic field of the first and second repulsive permanent magnet rings 61 and 62 allows for greater suspension force with fewer permanent magnets.

[0067] The embodiments described are preferred implementations of the present invention, but the present invention is not limited to the above implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention are within the scope of protection of the present invention.

Claims

1. A magnetic levitation flywheel energy storage device that shares axial magnetic flux between a motor and a magnetic bearing system, characterized in that: It includes a five-degree-of-freedom magnetic bearing and an axial flux motor coaxially distributed inside a cylindrical housing (21); The five-degree-of-freedom magnetic bearing comprises a stationary part and a rotating part; the stationary part comprises a "pole shoe" type radial magnetic pole (31), a "pole shoe" type torsional stator (41), a radial control coil (32), a torsional coil (42) and a magnetic bearing axial coil (73); the "pole shoe" type radial magnetic pole (31) and the "pole shoe" type torsional stator (41) are fixed from top to bottom inside a cylindrical shell (21), and the radial control coil (32) is wound on the "pole shoe" type radial magnetic pole (31), and the torsional coil (42) is wound on the "pole shoe" type torsional stator (41), wherein " The number of "pole shoe" type radial magnetic poles (31) and "pole shoe" type torsion stators (41) is a multiple of 3; the rotating part includes a radial receiving ring (91), a torsion receiving ring (92), a radial bias magnetic flux receiving ring (93), a gyroscope-like flywheel (5), and a first repulsive permanent magnet ring (61); the flywheel (5) is suspended in the middle of the cylindrical shell (21); the radial receiving ring (91), the torsion receiving ring (92), and the radial bias magnetic flux receiving ring (93) are embedded in the outer wall of the flywheel (5); and the first repulsive permanent magnet ring (61) is embedded in the bottom of the flywheel (5); A second repulsive permanent magnet ring (62) is coaxially arranged opposite to the first repulsive permanent magnet ring (61), and the second repulsive permanent magnet ring (62) is embedded in a groove at the bottom of the cylindrical shell (21); a first embedded permanent magnet block (51) is vertically arranged on the inner side of the upper part of the flywheel (5), and a second embedded permanent magnet block (52) is horizontally arranged; the first embedded permanent magnet block (51) is located above the second embedded permanent magnet block (52), and the two are in contact; The axial flux motor is located in a groove (76) on the upper part of the flywheel (5), and comprises an axial flux motor main shaft (71), a motor stator (72), a motor rotor (74), a magnetically conductive ferrite (75) and a permanent magnet (77). The axial flux motor main shaft (71) is placed at the upper end of the through hole (10) in the middle of the flywheel (5); the motor stator (72) is located above the motor rotor (74) and is coaxially arranged on the axial flux motor main shaft (71); a permanent magnet (77) is fixed on the motor rotor (74), and the permanent magnet (77) is embedded in the flywheel (5); the magnetically conductive ferrite (75) is embedded in the bottom of the groove (76); the motor stator (72) and the magnetic bearing axial coil (73) are coaxially arranged; At the lower end of the through hole (10), a virtual main shaft (8) is provided coaxially with the axial flux motor main shaft (71), and the virtual main shaft (8) is connected to the bottom of the cylindrical shell (21).

2. The magnetic levitation flywheel energy storage device with shared axial magnetic flux between the motor and the magnetic bearing system according to claim 1 is characterized in that: The first embedded permanent magnet blocks (51) and the second embedded permanent magnet blocks (52) are both in an even number, and two adjacent ones form a group; when there is only one group of the first embedded permanent magnet blocks (51) and the second embedded permanent magnet blocks (52), no magnetic isolation aluminum block is provided; if the number of groups of the first embedded permanent magnet blocks (51) and the second embedded permanent magnet blocks (52) is greater than or equal to 2, a magnetic isolation aluminum block is provided between each group.

3. The magnetic levitation flywheel energy storage device with shared axial magnetic flux between the motor and the magnetic bearing system according to claim 1, characterized in that: The flywheel (5) is thick at the top and thin at the bottom, with a disc-shaped bottom, and the main body is made of carbon fiber material.

4. The magnetic levitation flywheel energy storage device with shared axial magnetic flux between the motor and the magnetic bearing system according to claim 1, characterized in that: An odd number of radially biased magnetic flux receiving rings (93) are arranged at intervals on the outer side of the upper portion of the flywheel (5); an odd number of radially biased magnetic flux receiving rings (91) are arranged at intervals on the outer side of the flywheel (5) below the radially biased magnetic flux receiving rings (93); and an odd number of torsion receiving rings (92) are arranged at intervals on the outer side of the lower portion of the flywheel (5); the radial receiving rings (91), the torsion receiving rings (92) and the radially biased magnetic flux receiving rings (93) are coaxially arranged.

5. The magnetic levitation flywheel energy storage device with shared axial magnetic flux between the motor and the magnetic bearing system according to claim 4 is characterized in that: Receiving rings are also provided on the cylindrical housing (21) corresponding to the radial receiving ring (91), the torsion receiving ring (92) and the radial bias magnetic flux receiving ring (93), and all the receiving rings are made of metal material.

6. The magnetic levitation flywheel energy storage device with shared axial magnetic flux between the motor and the magnetic bearing system according to claim 1, characterized in that: The parts of the "pole shoe" type radial magnetic pole (31) close to the radial receiving ring (91) and the parts of the "pole shoe" type torsion stator (41) close to the torsion receiving ring (92) are both arc-shaped.

7. The magnetic levitation flywheel energy storage device with shared axial magnetic flux between the motor and the magnetic bearing system according to claim 1, characterized in that: The magnetic pole thickness of the "pole shoe" type torsion stator (41) is smaller than the magnetic pole thickness of the "pole shoe" type radial magnetic pole (31).

8. The magnetic levitation flywheel energy storage device with shared axial magnetic flux between the motor and the magnetic bearing system according to claim 1, characterized in that: A layer of sound insulation cotton is installed on the inner surface of the cylindrical shell (21).

9. The magnetic levitation flywheel energy storage device with shared axial magnetic flux between the motor and the magnetic bearing system according to claim 1, characterized in that: The cylindrical shell (21) is tightly fixed to the upper end cover (1); a heat dissipation hole (11) is provided on the edge of the upper end cover (1); second heat dissipation holes (22) are provided on both sides and the bottom of the cylindrical shell (21); and a fin-shaped heat dissipation wing (23) is fixed to the outer side of the cylindrical shell (21).

10. The magnetic levitation flywheel energy storage device with shared axial magnetic flux between the motor and the magnetic bearing system according to claim 1, characterized in that: The number of the "pole shoe" type radial magnetic poles (31) and the "pole shoe" type torsion stator (41) are both 6, and two adjacent ones are regarded as one phase, which is divided into three phases A, B, and C. Current is passed through the coils of each phase at intervals.

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