A magnetic levitation flywheel energy storage device with feature balance

Abstract

The present invention discloses a magnetic levitation flywheel energy storage device with feature balance. The bottom end of the outer shell is fixedly provided with an outer shell torsion permanent magnet, a first repulsive permanent magnet ring, a bottom cast iron ring, and a second repulsive permanent magnet ring layer by layer radially inwards; the motor stator is fixed at the upper end inside the outer shell; the five-degree-of-freedom magnetic bearing includes upper and lower radial receiving rings and a flywheel torsion permanent magnet. The flywheel torsion permanent magnet is arranged at the periphery of the bottom of the flywheel, and the upper and lower radial receiving rings are arranged on both sides of the upper layer of the double-layer magnetic isolation aluminum ring. The lower layer of the double-layer magnetic isolation aluminum ring is sleeved on the flywheel disc. The flywheel disc, the flywheel short shaft, and the narrow cylinder are arranged in sequence from bottom to top. An axial receiving ring is sleeved on the top of the flywheel short shaft, and a permanent magnet patch ring is arranged outside the double-layer magnetic isolation aluminum ring; an axial stator is installed between the upper radial receiving ring and the axial receiving ring. An axial coil is fixed inside the axial stator, and a sunken torsion stator and an "H + X" type magnetic pole are arranged at intervals outside. The present invention simultaneously ensures the integration degree, energy storage performance, system loss, safety and stability, and cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of flywheel batteries, and particularly relates to a magnetic levitation flywheel energy storage device with balanced characteristics. Background Art

[0002] Magnetic levitation flywheel energy storage devices (flywheel batteries) break through the limitations of chemical batteries and achieve energy storage by physical methods. They have the characteristics of large and short charging and discharging currents, good environmental adaptability, high energy conversion efficiency, and long cycle life. Currently, magnetic levitation flywheel batteries have bottlenecks in actual application and popularization, that is, it is difficult to achieve a satisfactory effective balance in performance characteristics such as system integration, energy storage performance, system loss, safety and stability, and cost. The specific problems are as follows:

[0003] In terms of integration: Currently, the mainstream structural topology of flywheel energy storage devices usually has a long inertial main shaft, and key components such as magnetic bearings, flywheels, and motors are arranged around this inertial main shaft. Therefore, the integration of this type of structure is low, and it is only suitable for some occasions with weak axial space constraints. Moreover, this type of structure with a "long shaft" also limits the critical speed of the flywheel, which is not conducive to the improvement of flywheel energy storage performance. And in actual application, the flywheel energy storage device with an overly long axial length will force its carrier device to make corresponding adjustments in space. For some occasions with extremely high space constraints such as vehicles, ships, and space stations, this type of topological structure with an "overly long axial length" is not conducive to the wider application and promotion of flywheel batteries. Therefore, a type of "shaftless" (without an inertial main shaft passing through the flywheel and motor) flywheel battery topology has been designed (patent application number: CN201910072060.7, virtual shaft type magnetic levitation flywheel energy storage device for electric vehicles). This type of topological structure cancels the inertial main shaft passing through the flywheel and motor in the traditional sense, and uses some magnetic bearings placed above the flywheel and some magnetic bearings embedded in the flywheel. Therefore, to a large extent, it reduces the axial length of the overall flywheel battery system and significantly improves its integration. In addition, a type of shaftless ultra-thin magnetic levitation flywheel battery (patent application number: CN 202110521559.9, an ultra-thin vehicle-mounted magnetic levitation flywheel battery and its working method) further improves the axial integration. This type of structure further compresses the axial length of the flywheel battery by adjusting the arrangement positions and methods of the magnetic bearings, motors, and flywheels. However, in any case, in the topological structure of the "shaftless" flywheel battery system in the prior art, it is still limited to the way of stacking the motor and the flywheel vertically or nesting some components axially in the axial direction. Therefore, the ultimate high integration has not been achieved in the axial direction, and thus there is still room for further improvement in the integration of the flywheel battery topological structure in the prior art.

[0004] In terms of energy storage performance: To improve the energy storage performance of the flywheel battery system, the material selection of the flywheel is particularly crucial. Existing technologies mainly include metal materials, composite materials, and the reuse of two materials, etc. Flywheels made of metal materials are inexpensive, but their low tensile properties limit the upper limit of their rotational speed. This means that increasing the energy storage performance parameters requires a significant increase in the weight and volume of the flywheel. And increasing the weight and volume will inevitably increase the moment of inertia, leading to a decrease in the safety of the flywheel. Once the flywheel battery is too heavy, it will cause its carrying device to consume extra energy to support the flywheel battery, reducing the energy utilization rate of the overall system. For example, in-vehicle flywheel batteries are often used in combination with other power batteries. If the entire flywheel battery system is too large or too heavy, it will not only occupy the space and energy resources of the original power battery, but also the energy storage performance advantage of the flywheel battery itself will be restricted by the vehicle space and cannot be fully utilized, reducing the energy utilization rate. In addition, although high-strength composite materials have good tensile strength and very high safety, the processing and manufacturing costs of composite materials are very high. Therefore, it is a better choice to reuse metal materials and composite materials to give full play to the advantages of each material. That is, it is very crucial to find a balance between metal and composite materials to achieve a balance among energy storage performance, safety, and cost.

[0005] In terms of system losses: Since the losses of the flywheel battery system mainly depend on standby losses, and the suspension support losses of magnetic bearings account for the vast majority of the overall standby losses, it is particularly crucial to design a reasonable low-loss magnetic bearing structure. In terms of magnetic bearing suspension support, currently, the mainstream flywheel battery systems use suction magnetic bearings to keep the flywheel stably suspended, and a few flywheel battery systems have proposed using repulsive magnetic bearings for support. In order to improve the control stiffness, accuracy, self-stabilization ability of the flywheel, and reduce control losses, the reuse of the two types of magnetic bearings in the flywheel battery system is the future development trend of the flywheel battery system.

[0006] In terms of safety and stability: Under the requirement of high integration, in the "shaftless" magnetic levitation flywheel battery system topology in the existing technology, since the weight and eccentricity adjustment of the flywheel are provided by magnetic bearings placed in the axial direction of the flywheel, the bias magnetic circuit will be coupled with the control magnetic circuit to a certain extent, increasing the control cost and affecting the control effect. In addition, in the existing technology, the motor used in the flywheel battery system is usually arranged axially with the flywheel. Since the centers of gravity of the motor and the flywheel do not coincide, that is, there is a distance between them in the axial direction. Once the flywheel is eccentric, before the magnetic bearing has time to act and make it return to the equilibrium position, the eccentricity of the flywheel will inevitably lead to the eccentricity of the motor, and the eccentricity of the motor will cause the magnetic field of the motor to lose balance, which will also accelerate the eccentricity of the flywheel. Therefore, the magnetic bearing system and the motor system will interact and influence each other; and it is a future trend to design a flywheel battery topology with the centers of gravity of the flywheel and the motor as coincident as possible and in a flattened ultra-thin structure. At the same time, since the flattened ultra-thin topology that can withstand higher speeds will cause a serious gyroscopic effect, it is urgent to design a magnetic bearing with higher precision and stability suitable for this type of topology. In addition, in order to ensure the safety of the overall structure under a higher gyroscopic effect, it is also very necessary to optimize and redesign structures such as the outer shell to improve safety.

[0007] In summary, when designing a flywheel energy storage device in the existing technology, it is difficult to achieve an effective balance when weighing various performance characteristics. Therefore, how to consider overall, incorporate various aspects into the overall consideration, and strive to achieve a balance of all aspects to achieve the effect of feature balance. It is urgent to design a reasonable magnetic levitation flywheel energy storage device that considers various features and achieves effective balance. Summary of the Invention

[0008] In view of this, the present invention provides a magnetic levitation flywheel energy storage device with balanced features.

[0009] The present invention achieves the above technical objectives through the following technical means.

[0010] A magnetic levitation flywheel energy storage device with balanced features, comprising:

[0011] An outer shell, on the bottom end, the outer shell torsion permanent magnet, the first repulsive permanent magnet ring, the bottom cast iron ring and the second repulsive permanent magnet ring are fixedly arranged layer by layer radially inwards;

[0012] and a five-degree-of-freedom magnetic bearing, a flywheel, and a motor stator coaxially distributed in the housing cavity; the motor stator is fixed to the upper end inside the housing cavity; the five-degree-of-freedom magnetic bearing includes a stationary part and a rotating part, the stationary part includes an axial stator, three sunken torsion stators, and three "H+X" type magnetic poles, the sunken torsion stators and the "H+X" type magnetic poles are arranged at intervals on the side of the axial stator, the rotating part includes an upper radial receiving ring, a lower radial receiving ring, and a flywheel torsion permanent magnet; the flywheel includes an upper layer part and a lower flywheel main body; a flywheel repulsive permanent magnet ring is embedded at the bottom of the flywheel main body, and flywheel torsion permanent magnets are arranged around the bottom, a narrow cylinder, a flywheel short shaft, and a flywheel disc are coaxially arranged in sequence from top to bottom on the upper part of the flywheel main body, and an axial receiving ring is sleeved on the top of the flywheel short shaft; the upper layer part includes a double-layer magnetic isolation aluminum ring, a magnetic isolation aluminum ring, and a permanent magnet patch ring, the lower layer of the double-layer magnetic isolation aluminum ring is sleeved on the flywheel disc, the upper and lower sides inside the upper layer part are provided with an upper radial receiving ring and a lower radial receiving ring, the magnetic isolation aluminum ring is sleeved outside the double-layer magnetic isolation aluminum ring, and the upper part of the magnetic isolation aluminum ring is attached to the permanent magnet patch ring along the circumference; a fixed ring is installed between the upper radial receiving ring and the axial receiving ring, the lower end of the fixed ring is connected to the axial stator, an axial coil is fixed inside the axial stator, and a stator magnetic isolation aluminum ring and a stator yoke are sequentially sleeved outside the axial stator.

[0013] In the above technical solution, the sunken torsion stator is a cuboid structure with the end warping downward, and the left and right sides of the downward part of the end section are hollowed out; a torsion coil is wound around the middle part of the sunken torsion stator along the circumferential direction.

[0014] In the above technical solution, the "H+X" type magnetic pole includes an X-type coil bracket, convex poles extend outwards from the four corners of the X-type coil bracket respectively, radial permanent magnets are also provided on the upper and lower sides of the X-type coil bracket, and a radial coil is wound along the radial direction in the middle part of the X-type coil bracket.

[0015] The above technical solution further includes an energy absorption structure, which is composed of a plurality of energy absorption rings coaxially combined at equal intervals along the axis, and each energy absorption ring is composed of a plurality of hollow energy absorption boxes inserted on the energy absorption box base at equal intervals along the circumference, and the energy absorption box base is fixed inside the housing.

[0016] In the above technical solution, a guiding groove is provided at the waist line of the energy absorption box.

[0017] In the above technical solution, the flywheel main body, the narrow cylinder, the flywheel disc, and the flywheel short shaft are all made of carbon fiber materials.

[0018] In the above technical solution, the permanent magnet patch ring is composed of radial N-pole permanent magnets and radial S-pole permanent magnets alternatingly.

[0019] In the above technical solution, the motor stator is successively an A-phase stator, a B-phase stator, and a C-phase stator in the clockwise direction.

[0020] In the above technical solution, the housing further includes a cylindrical housing and an upper end cover. The upper end of the cylindrical housing is fixedly connected with the upper end cover, and the lower end is successively fixedly connected with a housing torsion permanent magnet, a first repulsive force permanent magnet ring, a bottom cast iron ring, and a second repulsive force permanent magnet ring.

[0021] In the above technical solution, the upper end cover is provided with a central hole, and a plurality of wire holes are provided near the central hole. Two circles of heat dissipation holes are arranged along the circumference and concentrically away from the central hole.

[0022] The beneficial effects of the present invention are as follows:

[0023] (1) In the present invention, the flywheel and the motor are arranged in the radial direction and their centers of gravity coincide, realizing the "zero arrangement" of the flywheel and the motor in the axial direction. This not only breaks the inherent thinking of traditional flywheel batteries that are only highly integrated in the axial direction, but also because the centers of gravity of the flywheel and the motor coincide, the eccentricity of the flywheel will not further affect the motor, greatly improving the stability of the system.

[0024] (2) According to the "zero arrangement" of the flywheel and the motor in the axial direction, the present invention designs a five-degree-of-freedom magnetic bearing system with high integration, high control precision, and low energy consumption. In terms of high integration: The five-degree-of-freedom magnetic bearing is wrapped inside the motor stator, and due to the "zero arrangement" of the coincident centers of gravity, the high integration of the flywheel battery is ensured. In terms of high-precision control and low energy consumption: In the axial degree of freedom, when the flywheel deviates under the support of the traditional suction-type magnetic bearing, a greater electromagnetic force will be generated in the deviation direction, which is not conducive to the flywheel returning to the equilibrium position. By combining permanent magnets with different magnetization directions, the present invention forms a repulsive force with a relatively large stiffness, which can not only bear the self-weight of the flywheel but also have a self-recovery ability with a certain margin to resist external interference. In addition, the torsional degree of freedom also forms a repulsive force with a certain margin through a clever design and can achieve self-balancing under the condition of small disturbances, thus significantly reducing the control loss of the system. And in the face of relatively strong disturbances, active magnetic bearings with high control precision are configured for all five degrees of freedom to improve the control precision and stability of the system.

[0025] (3) The "H+X" type magnetic poles of the present invention overcome the disadvantages of the traditional double-layer stator magnetic poles, such as insufficient space due to winding multiple groups of coils, poor heat dissipation, and serious mutual inductance of the parallel coils, resulting in heating and reduced control precision.

[0026] (4) The sunken torsion stator of the present invention has the torsion coil wound in the middle part, which is very beneficial to heat dissipation and enhanced torsion control effect; in addition, due to the unique radial and torsion pole design, the winding directions of the torsion coil of the sunken torsion stator and the radial coil of the "H+X" type magnetic pole are perpendicular to each other, ensuring that there will be no mutual induction between the two when the spacing is close, thereby improving the control accuracy.

[0027] (5) Since the flywheel of the traditional "shaftless" flywheel battery system needs to work together with the magnetic bearing to provide a magnetic circuit to provide stable suspension of the flywheel, its flywheel is usually designed with metal materials. The present invention uses composite materials and metal materials to make the flywheel. Different from the traditional "hybrid" design with metal materials as the main material and composite materials as the auxiliary material, the present invention uses composite materials as the main body and metal materials as the auxiliary material, which not only ensures the direction of the magnetic circuit, but also achieves the lightweight, energy storage performance and safety performance of the system.

[0028] (6) In order to further ensure the safety performance of the system, the present invention adds an aluminum energy-absorbing structure on the inner surface of the solid metal shell. The structure is composed of multiple energy-absorbing rings axially combined. The energy of the flywheel fragments is absorbed by the collapse energy absorption of the energy-absorbing structure.

[0029] (7) The "H+X" type magnetic pole of the present invention can not only achieve the bias effect with fewer permanent magnets, but also achieve the effect of low energy consumption and high stability control with fewer radial coils, thereby significantly reducing material costs; and the energy absorption structure design in the shell also reduces the thickness of the flywheel solid shell. When the energy absorption structure is damaged, the energy absorption ring at the corresponding position can be replaced, thereby further reducing the manufacturing and maintenance costs of the flywheel battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a cross-sectional view of the overall structure of the magnetic levitation flywheel energy storage device of the present invention;

[0031] Figure 2 This is an oblique top view of the overall structure of the magnetic levitation flywheel energy storage device of the present invention;

[0032] Figure 3 yes Figure 1 A magnified view of the flywheel structure;

[0033] Figure 4 It is an enlarged structural diagram of the motor in the present invention;

[0034] Figure 5 yes Figure 1 A magnified view of the stationary structure of the five-degree-of-freedom magnetic bearing;

[0035] Figure 6 This is an assembly diagram of the auxiliary bearing, the auxiliary bearing bracket and the axial stator in the present invention;

[0036] Figure 7 This is an enlarged view of the structure of a single energy absorption box in the present invention;

[0037] Figure 8 yes Figure 1 Assembly drawing of the middle energy absorbing structure and the outer shell;

[0038] Figure 9 This is a schematic diagram of the principle of achieving radial two-degree-of-freedom balance control when the magnetic levitation flywheel energy storage device of the present invention is in operation;

[0039] Figure 10 This is an oblique view schematic diagram of the radial two-degree-of-freedom balance control achieved during operation of the magnetic levitation flywheel energy storage device of the present invention;

[0040] Figure 11 This is a schematic diagram of the principle of achieving axial single-degree-of-freedom balance control when the magnetic levitation flywheel energy storage device of the present invention is in operation;

[0041] Figure 12 This is a schematic diagram of the principle of achieving torsional two-degree-of-freedom balance control when the magnetic levitation flywheel energy storage device of the present invention is in operation;

[0042] In the figure: 11. Upper end cover; 111. Heat dissipation holes; 112. Wiring holes; 21. Cylindrical housing; 22. Housing torsion permanent magnet; 23. Housing bottom ring; 24. First repulsive permanent magnet ring; 25. Second repulsive permanent magnet ring; 26. Housing inner disc; 27. Bottom cast iron ring; 3. Energy absorption structure; 31. Energy absorption ring; 32. Energy absorption box; 321. Guide groove; 311. Energy absorption box base; 4. Motor stator; 41. A-phase stator; 42. B-phase stator; 43. C-phase stator; 5. Flywheel; 51. Flywheel body; 511. Narrow cylinder; 512. Flywheel disc; 513. Flywheel short shaft; 52. Flywheel repulsive permanent magnet ring; 53 .Flywheel torsion permanent magnet; 54. Permanent magnet patch ring; 541. Radial N-pole permanent magnet; 542. Radial S-pole permanent magnet; 55. Magnetic isolation aluminum ring; 56. Double-layer magnetic isolation aluminum ring; 57. Upper radial receiving ring; 58. Lower radial receiving ring; 59. Axial receiving ring; 61. Axial stator; 611. Fixed ring; 62. Stator magnetic isolation aluminum ring; 63. Stator yoke; 64. Torsion coil; 65. Sunken torsion stator; 66. "H+X" type magnetic pole; 661. X-type coil bracket; 67. Axial coil; 68. Radial permanent magnet; 69. Radial coil; 681. Permanent magnet bracket; 71. Auxiliary bearing; 72. Auxiliary bearing bracket. DETAILED DESCRIPTION

[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0044] See also Figure 1 、 2, the outermost part of the magnetic levitation flywheel energy storage device of the present invention is a housing mainly composed of a cylindrical housing 21. The upper end of the cylindrical housing 21 is tightly fixed with an upper end cover 11. The lower end of the cylindrical housing 21 is tightly fixed with a housing torsion permanent magnet 22, a housing bottom ring 23, a first repulsive permanent magnet ring 24, a bottom cast iron ring 27, a second repulsive permanent magnet ring 25, and a housing inner disc 26 layer by layer radially inward. The above parts form a housing cavity. The upper end cover 11 is a disc-shaped with a hole in the center. A plurality of circular wire holes 112 are evenly opened along the circumference near the central hole of the upper end cover 11 to facilitate the wiring of each coil. Two circles of trapezoidal holes are opened along the circumference and coaxial with the center at a place farther from the central hole as heat dissipation holes 111 to achieve the heat dissipation of the overall device. The cylindrical housing 21 has a hollow structure at the upper and lower parts, and a protruding section is provided horizontally inward at the bottom to fix other bottom accessories. The cross-section of the annular housing torsion permanent magnet 22 is trapezoidal, and the length of the lower bottom side of the trapezoid is the same as the height of the horizontal protruding section of the cylindrical housing 21. The lower bottom side of the trapezoid is fixed to the protruding section to ensure that they are flush. The inner side of the shorter upper bottom side of the trapezoid is fixed with the housing bottom ring 23, and the height of the housing bottom ring 23 is the same as the length of the upper bottom side. In the same way, the first repulsive permanent magnet ring 24, the bottom cast iron ring 27, the second repulsive permanent magnet ring 25, the housing inner disc 26, etc. are fixed coaxially from the outside to the inside in turn, so as to fill the hollow area of the lower bottom surface of the cylindrical housing 21. The assembly composed of the above parts acts as a housing bottom cover. The housing bottom ring 23 and the housing inner disc 26 are only used to fill the hollow area of the lower bottom surface of the cylindrical housing 21.

[0045] Inside the housing cavity, a five-degree-of-freedom magnetic bearing, a flywheel 5, and a motor stator 4 are coaxially distributed. The five-degree-of-freedom magnetic bearing includes a stationary part and a rotating part. The stationary part includes an axial stator 61, three sunken torsion stators 65, and three "H+X"-type magnetic poles 66 (as Figure 5 shown), and the sunken torsion stators 65 and the "H+X"-type magnetic poles 66 are arranged at intervals on the side of the axial stator 61; the rotating part includes an upper radial receiving ring 57, a lower radial receiving ring 58, and a flywheel torsion permanent magnet 53 (as Figure 3 shown), and the rotating part of the five-degree-of-freedom magnetic bearing is embedded in the flywheel 5. The upper end of the inner surface of the cylindrical housing 21 is fixed with the motor stator 4. The motor stator 4 is composed of a phase-A stator 41, a phase-B stator 42, and a phase-C stator 43 in a clockwise direction, as Figure 4 shown.

[0046] See Figure 3, as a whole, the flywheel 5 appears to be a disc structure with a single-direction short shaft, higher on both sides and lower in the middle. It consists of two closely connected upper and lower layers, and the lower layer undertakes the functions of energy storage and fixing the upper control part. The flywheel main body 51 is the main part of the lower layer. It is disc-shaped as a whole and has a groove around the bottom. The flywheel repulsive permanent magnet ring 52 is embedded in the groove, and the bottom edge is chamfered and a trapezoidal flywheel torsion permanent magnet 53 is pasted at the chamfer. The upper surface of the flywheel main body 51 has a three-layer structure. The bottom layer is a solid flywheel disc 512 protruding axially from the center. The middle layer - a flywheel short shaft 513 stretched axially is placed at the center of the disc. The narrow cylinder 511 of the upper layer is connected to the top of the flywheel short shaft 513. The three are coaxially and firmly fixed layer by layer. The inner diameter of the axial receiving ring 59 is the same as the outer diameter of the flywheel short shaft 513. It is sleeved on the top position of the flywheel short shaft 513, and its upper end face is parallel to the upper end face of the flywheel short shaft 513. The upper control part is stacked by various ring-shaped parts. First, it is a double-layer magnetic isolation aluminum ring 56 for bearing and isolating the magnetic circuit. The cross-section of the double-layer magnetic isolation aluminum ring 56 is in a two-layer stepped shape and is sleeved on the flywheel disc 512. The outer diameter of the double-layer magnetic isolation aluminum ring 56 is slightly smaller than that of the flywheel main body 51, and the height of the lower step is the same as the height of the flywheel disc 512; the outer diameter of the magnetic isolation aluminum ring 55 is the same as that of the flywheel main body 51 and is sleeved on the bottom of the double-layer magnetic isolation aluminum ring 56; the upper part of the magnetic isolation aluminum ring 55 is attached to the permanent magnet patch ring 54 along the circumference. The permanent magnet patch ring 54 is composed of radially arranged N-pole permanent magnets 541 and S-pole permanent magnets 542 alternating (see Figure 4 ), and finally combined into a ring with an inner diameter equal to the outer diameter of the double-layer magnetic isolation aluminum ring 56 and an outer diameter the same as that of the magnetic isolation aluminum ring 55; the height of the permanent magnet patch ring 54 is the same as that of the double-layer magnetic isolation aluminum ring 56.

[0047] Continue to refer to Figure 3 , in the stepped space of the double-layer magnetic isolation aluminum ring 56, the upper radial receiving ring 57 and the lower radial receiving ring 58 are placed. The two receiving rings with rectangular cross-sections are of the same size and shape. The outer surfaces are attached to the double-layer magnetic isolation aluminum ring 56, and the height is the same as the stepped space; after the two receiving rings are embedded, the upper assembly of the flywheel is completed. The lower ring of the double-layer magnetic isolation aluminum ring 56 is sleeved on the flywheel disc 512 to complete the assembly of the flywheel 5. The inner side surfaces of the upper radial receiving ring 57 and the lower radial receiving ring 58 are arc-shaped.

[0048] Install the stationary part of the five-degree-of-freedom magnetic bearing between the upper radial receiving ring 57 and the axial receiving ring 59. This part is installed and fixed to the fixed ring 611 through the central hole of the upper end cover 11, and is fixed by the fixed ring 611, as shown in Figure 6As shown; the fixed ring 611 is divided into upper and lower parts. The radius of the upper part is greater than that of the lower part, and screw holes are provided in the upper part for fixing on the upper end cover 11 of the housing. The outer diameter of the lower part is the same as the inner diameter of the central hole of the upper end cover 11, and the lower half is inserted from the central hole. The aluminum auxiliary bearing bracket 72 is similar in structure to the fixed ring 611. The radius of the larger part is the same as the inner diameter of the fixed ring 611. The auxiliary bearing bracket 72 is fixed to the upper end of the axial stator 61, and the auxiliary bearing 71 is fixed inside. A part of the upper surface of the axial stator 61 is connected to the lower surface of the fixed ring 611, and a part is fixed to the auxiliary bearing bracket 72. The axial coil 67 is fixed on the inner surface of the axial stator 61, and the stator magnetic isolation aluminum ring 62 is fixed on the outer surface of the axial stator 61. The upper and lower surfaces of the stator magnetic isolation aluminum ring 62 are flush with the upper and lower surfaces of the axial stator 61 respectively. In order to fix the "H+X" type magnetic pole 66 and the sunken torsion stator 65, the stator yoke 63 is used. As Figure 5 shown, where the upper and lower surfaces of the stator yoke 63 are flush with the stator magnetic isolation aluminum ring 62, and the inner diameter is the same as the outer diameter of the stator magnetic isolation aluminum ring 62. After sleeving it on the outside of the stator magnetic isolation aluminum ring 62, the assembly of the stator can be carried out.

[0049] The stator fixed to the stator yoke 63 is divided into an "H+X" type magnetic pole 66 and a sunken torsion stator 65. The bottoms of both are arc-shaped and can fit the periphery of the stator yoke 63. In the present invention, in order to achieve the purposes of reducing magnetic circuit coupling, reducing material loss, and increasing safety, the "H+X" type magnetic pole 66 and the sunken torsion stator 65 are designed. The "H+X" type magnetic pole 66 has an X-shaped coil bracket 661 as the main body. Four protruding poles extend outward from the four corners of the X-shaped coil bracket 661 as the main magnetic conduction parts. The tops of the protruding poles are arc-shaped and are used to cooperate with the upper radial receiving ring 57 and the lower radial receiving ring 58 for magnetic conduction. At the same time, for fixation, a part of the X-shaped coil bracket 661 also extends inward for fitting with the stator yoke 63. Permanent magnet brackets 681 for fixing permanent magnets are provided on both the upper and lower parts of the X-shaped coil bracket 661. The brackets are long trapezoids, and there is a gap between the lower surface and the X-shaped coil bracket 661. A long strip-shaped radial permanent magnet 68 is provided at the middle position of the upper part of the permanent magnet bracket 681. The upper and lower surfaces of the radial permanent magnet 68 are flush with the permanent magnet bracket 681. Radial permanent magnets 68 with the same shape and magnetization direction are fixed in the same way at the lower part of the permanent magnet bracket 681; the middle part of the X-shaped coil bracket 661 is used to wind the radial coil 69. The entire "H+X" type magnetic pole 66 is symmetric about its own center point both vertically and horizontally; three structurally identical "H+X" type magnetic poles 66 are installed in a circumferential distribution when installed, and the bottom is fixed at the middle position of the stator yoke 63. The sunken torsion stator 65 is a cuboid structure with the end warping downward. The left and right sides of the downward part at the end are hollowed out, so as to form a structure similar to a pole shoe at the end to enhance the control effect. The thickness of the end of the sunken torsion stator 65 is slightly smaller than that of the lower radial receiving ring 58. A torsion coil 64 is wound around the middle part of the sunken torsion stator 65; when installed, the heights of three identical sunken torsion stators 65 are located in the middle part of the X-shaped coil bracket 661 and are installed at equal angles in the circumferential direction between every two radial coils 69.

[0050] To improve the overall stability, an energy absorption structure 3 is installed on the inner surface of the cylindrical housing 21. The specific assembly is as Figure 8 shown. The energy absorption structure 3 is composed of a plurality of energy absorption rings 31 coaxially combined at equal intervals along the axial direction. Each energy absorption ring 31 has a plurality of energy absorption boxes 32 ( Figure 7 ) inserted at equal intervals in the circumferential direction on the energy absorption box base 311. The energy absorption box base 311 is fixed on the inner surface of the cylindrical housing 21; the number of axially installed energy absorption rings 31 is selected according to actual needs. The energy absorption structure 3 is made of aluminum foam.

[0051] When the magnetic levitation flywheel energy storage device of the present invention works, the conversion between electrical energy and mechanical energy is realized through the rotation of the flywheel 5, which is divided into three stages: charging, energy storage, and discharging:

[0052] (1) Charging stage

[0053] The rotation of the flywheel 5 is achieved by a permanent magnet synchronous motor composed of a permanent magnet patch ring 54 and a motor stator 4. Specifically, currents are passed through the windings of the A-phase stator 41, B-phase stator 42, and C-phase stator 43 in the motor stator 4, so that they interact with the radial N-pole permanent magnets 541 and radial S-pole permanent magnets 542 in the permanent magnet patch ring 54 to ensure that the flywheel 5 can achieve accelerated rotation, reaching the conversion process between electrical energy and mechanical energy and realizing the input of electrical energy.

[0054] (2) Energy storage stage

[0055] When the input electrical energy is sufficient and the magnetic levitation flywheel energy storage device is in a full state, the motor runs idly and the flywheel 5 maintains a constant rotational speed; before the next discharge state, there is no energy exchange in the magnetic levitation flywheel energy storage device.

[0056] (3) Discharge stage

[0057] In this stage, the permanent magnet synchronous motor composed of the permanent magnet patch ring 54 of the flywheel and the motor stator 4 acts as a generator, and energy is output from the flywheel 5 to realize the conversion between mechanical energy and electrical energy.

[0058] The present invention breaks away from the design of traditional magnetic circuits. By designing the "H+X"-type magnetic poles 66, sunken torsion stators 65, and reasonably utilizing repulsive forces and electromagnetic forces, it has higher-precision control on the basis of simplifying the structure and reducing the thickness, and can meet the 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 the traditional structure, adopting the present invention can also reduce the current loss during control. The specific implementation method is as follows:

[0059] The implementation process of axial single-degree-of-freedom control (including passive suspension and axial control of axial single-degree-of-freedom): As Figure 11As shown, the first repulsive permanent magnet ring 24 and the second repulsive permanent magnet ring 25 with opposite N - pole directions and both pointing to the bottom cast iron ring 27 generate an axially upward magnetic flux through the magnetic flux enhancement effect of the bottom cast iron ring 27. This magnetic flux interacts with the axially downward magnetic flux generated by the flywheel repulsive permanent magnet ring 52 magnetized in the negative axial direction, generating a repulsive force in the positive axial direction on the flywheel 5. By offsetting the gravity of the flywheel 5 itself with this repulsive force, the static suspension of the flywheel 5 is achieved. Compared with the structure using repulsive force to achieve suspension in the prior art, the structure of the combination of permanent magnets and magnetic flux enhancement rings used in the present invention can achieve a stronger and more stable suspension force with a thinner permanent magnet thickness. At the same time, the use of repulsive force also enables the structure to reduce the influence of disturbances through self - balance during small disturbances, reducing the loss of the axial coil 67. Axial control is achieved by the electromagnetic force generated by the energization of the axial coil 67. When it is detected that the flywheel rotor is disturbed beyond the allowable range of self - balance in the axial single - degree - of - freedom, a control current is passed through the axial coil 67, and the magnetic circuit generated is as Figure 11 shown by the solid line. Starting from the axial stator 61, it passes through the air gap between the axial stator 61 and the upper part of the axial receiving ring 59 to reach the axial receiving ring 59, and flows out through the lower air gap and returns to the axial stator 61, forming a complete magnetic circuit. And through the axial receiving ring 59, a control magnetic pulling force is generated on the flywheel 5 to make the flywheel return to the axial equilibrium position.

[0060] Realization of radial two - degree - of - freedom control: As Figure 9 , 10 shown, for the convenience of introduction, the three "H + X" - type magnetic poles 66 are divided into A, B, and C poles, and the following will introduce with the A - pole. Two identical radial permanent magnets 68 are symmetrically distributed on the upper and lower sides of the "H + X" - type magnetic pole 66, as Figure 9As shown by the dashed lines and arrows, the flux of the upper radial permanent magnet starts from the N pole, passes through the permanent magnet support 681 integrated with the upper half of the "H+X" type magnetic pole 66, reaches the air gap between the "H+X" type magnetic pole 66 and the flywheel, then flows into the upper radial receiving ring 57, and returns to the upper half of the "H+X" type magnetic pole 66 through the air gap and then reaches the S pole of the upper radial permanent magnet to form a loop; the magnetic circuit of the lower radial permanent magnet is similar, and forms a loop through the "H+X" type magnetic pole 66 and the lower radial receiving ring 58; the combined action of the upper and lower radial permanent magnets achieves the effect of radial static bias; in order to achieve the control of two radial degrees of freedom, a radial coil 69 is arranged in the middle of the "H+X" type magnetic pole 66, and a control flux shown by the solid lines and arrows in the figure is generated by applying a control current; the control flux starts from the X-type coil support 661 and is divided into two paths, one path passes through the upper half of the "H+X" type magnetic pole 66 and the upper radial receiving ring 57, and the other path passes through the lower half of the "H+X" type magnetic pole 66 and the lower radial receiving ring 58, and finally the two paths of flux are aggregated at the X-type coil support 661 to form a complete control magnetic circuit. When the flywheel receives an axial disturbance, a combined magnetic pulling force is generated through the cooperation of the three radial poles A, B, and C to achieve the control of two radial degrees of freedom.

[0061] Realization of the control of two torsional degrees of freedom: As Figure 12 shown, in order to achieve torsional control, the present invention designs a sunken torsional stator 65; the flywheel torsional permanent magnet 53 and the housing torsional permanent magnet 22 are used to achieve the control in the case of small torsion, and the sunken torsional stator 65 is used to cooperate to achieve the control in the case of large torsion. When the flywheel 5 is slightly disturbed and generates a small torsion, the distance on one side between the housing torsional permanent magnet 22 magnetized obliquely downward and the flywheel torsional permanent magnet 53 magnetized obliquely upward decreases, and the repulsive force generated by the opposite N poles of the two torsional permanent magnets increases due to the reduction of the air gap, so that the flywheel 5 returns to the equilibrium position. When the torsional angle of the flywheel exceeds the threshold that can be corrected by the two torsional permanent magnets, the control flux generated by passing a current through the torsional coil 64 reaches the lower radial receiving ring 58 through the sunken torsional stator 65 and the air gap, generates an unbalanced pulling force on the lower layer of the flywheel compared with the upper layer, and achieves the effect of torsional control through the three sunken torsional stators 65 and the torsional coils 64 arranged at equal angles between the three radial poles A, B, and C.

[0062] In order to achieve the purpose of reducing magnetic circuit coupling and improving control accuracy, the present invention uses the idea of isolating bias magnetic flux and control magnetic flux. In the axial suspension, the flywheel repulsive permanent magnet ring 52 that realizes static suspension through repulsive force is placed at the bottom end of the flywheel, while the axial coil 67 is placed at the top end of the flywheel; in the radial control, the "H+X" type magnetic pole 66 is adopted, which divides the radial magnetic circuit into upper and lower layers, and the two layers of magnetic circuits act together to increase the stability of the flywheel. In addition, the radially wound radial coil 69 and the torsion coil 64 wound in the circumferential direction are perpendicular to each other, ensuring that there is no mutual inductance between the two when the distance is relatively close.

[0063] On the basis of achieving high control accuracy, this structure has better energy storage performance and better safety performance while being lightweight. The implementation method is as follows:

[0064] Realization of high safety: Compared with the high-permeability steel used in the past to ensure the magnetic path inside the flywheel, the present invention makes reasonable use of repulsive force, so that the magnetic path is not set inside the flywheel. Therefore, in the main part of the flywheel 5, namely the flywheel body 51, the flywheel disc 512, the narrow cylinder 511 and the flywheel short shaft 513, carbon fiber materials are used, which ensures that the flywheel has high tensile strength while maintaining dimensional stability and high resistance to deformation, and thus realizes no deformation during long-term use; at the same time, the carbon fiber material can reduce the weight by more than 60% compared with the high-performance steel of the same volume. When the flywheel 5 exceeds the critical speed and breaks into pieces, the radially ejected fragments first contact the energy absorption structure 3 and cause the energy absorption box 32 to generate a radial collapse deformation. During this process, most of the energy of the fragments is absorbed by the collapse energy absorption of the energy absorption structure 3, and then stops moving after contacting the cylindrical shell 21. The structure of a single energy absorption box 32 is as Figure 7 shown. In order to make full use of the deformation of the energy absorption box 32 to produce an energy absorption effect, a guiding groove 321 is provided at the waist line of each energy absorption box 32. When deformation occurs, the relatively fragile guiding groove 321 first collapses and deforms along the radial direction, ensuring that the collapse deformation of the entire energy absorption box 32 is in the radial direction. Using the energy absorption structure 3 can increase safety. At the same time, the hollow energy absorption box 32 can reduce material loss and overall weight compared with the solid one, and the energy absorption structure 3 composed of multiple energy absorption rings 31 only needs to replace the damaged energy absorption ring during maintenance and replacement, reducing the maintenance cost. For the fragments ejected axially upward, the special X-shaped structure of the "H+X" type magnetic pole 66 can act as a shock absorber while saving materials, reducing the damage to the outside world caused by the axially ejected fragments.

[0065] Realization of high energy storage performance: In the present invention, the flywheel 5 is designed in a "hybrid" manner with composite materials as the main component and metal materials as the auxiliary component. Specifically, the flywheel body 51, the flywheel disk 512, the narrow cylinder 511, and the flywheel short shaft 513 are made of carbon fiber materials, and the other parts use metal materials; the carbon fiber materials widely used in the flywheel 5 have a very large specific strength (the ratio of the maximum axial stress to the density), and have a larger energy storage density under the same structure, improving the energy storage performance of the flywheel.

[0066] At the same time, in terms of cost, the present invention has lower control losses and lower manufacturing costs.

[0067] Realization of low losses: When the flywheel 5 is under balance control (including radial two-degree-of-freedom control, torsional two-degree-of-freedom control, and axial single-degree-of-freedom control), the present invention adopts a method in which repulsive force and electromagnetic force act together. The flywheel is less disturbed axially and torsionally, and can achieve self-balancing effects respectively through the interaction between repulsive force rings (the torsional part includes the flywheel torsional permanent magnet 53 and the housing torsional permanent magnet 22, and the axial part includes the flywheel repulsive permanent magnet ring 52, the first repulsive permanent magnet ring 24, the bottom cast iron ring 27, and the second repulsive permanent magnet ring 25), reducing the loss of control current. The "H+X" type magnetic pole 66 forms a loop by itself for a single stator, so that the radial coil 69 can achieve radial two-degree-of-freedom control with a smaller control current. Combining the above designs, the overall purpose of low-loss operation is achieved.

[0068] Realization of low cost: The "H+X" type magnetic pole 66 can achieve flywheel biasing with fewer permanent magnets, and the design of a single radial coil reduces the loss of coil materials. When axially suspended, through the enhanced magnetic field effect of the bottom cast iron ring 27, a large suspension force can be achieved with fewer permanent magnets. In addition, the energy absorption structure 3 reduces the thickness of the solid flywheel housing. When the energy absorption structure is damaged, only the energy absorption ring 31 at the corresponding position needs to be replaced, thus further reducing the manufacturing and maintenance costs of the flywheel battery system.

[0069] The described embodiments are the preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Without departing from the essential content of the present invention, any obvious improvements, substitutions, or variations that those skilled in the art can make all belong to the protection scope of the present invention.

Claims

1. A magnetic levitation flywheel energy storage device with feature balance, characterized in that, Comprising: A housing, with a housing torsion permanent magnet (22), a first repulsive permanent magnet ring (24), a bottom cast iron ring (27), and a second repulsive permanent magnet ring (25) fixed layer by layer radially inwards at the bottom end; And a five-degree-of-freedom magnetic bearing, a flywheel (5), and a motor stator (4) coaxially distributed in the housing cavity; the motor stator (4) is fixed at the upper end inside the housing cavity; the five-degree-of-freedom magnetic bearing includes a stationary part and a rotating part, the stationary part includes an axial stator (61), three sunken torsion stators (65), and three "H + X" type magnetic poles (66), the sunken torsion stators (65) and the "H + X" type magnetic poles (66) are arranged at intervals on the side of the axial stator (61), the rotating part includes an upper radial receiving ring (57), a lower radial receiving ring (58), and a flywheel torsion permanent magnet (53); the flywheel (5) includes an upper layer part and a lower flywheel main body (51); a flywheel repulsive permanent magnet ring (52) is embedded at the bottom of the flywheel main body (51), and flywheel torsion permanent magnets (53) are provided around the bottom, the upper part of the flywheel main body (51) is coaxially provided with a narrow cylinder (511), a flywheel short shaft (513), and a flywheel disc (512) from top to bottom in sequence, an axial receiving ring (59) is sleeved on the top of the flywheel short shaft (513); the upper layer part includes a double-layer magnetic isolation aluminum ring (56), a magnetic isolation aluminum ring (55), and a permanent magnet patch ring (54), the lower layer of the double-layer magnetic isolation aluminum ring (56) is sleeved on the flywheel disc (512), the upper and lower sides inside the upper layer part are provided with an upper radial receiving ring (57) and a lower radial receiving ring (58), the magnetic isolation aluminum ring (55) is sleeved outside the double-layer magnetic isolation aluminum ring (56), and the upper part of the magnetic isolation aluminum ring (55) is attached to the permanent magnet patch ring (54) along the circumference; a fixed ring (611) is installed between the upper radial receiving ring (57) and the axial receiving ring (59), the lower end of the fixed ring (611) is connected to the axial stator (61), an axial coil (67) is fixed inside the axial stator (61), and a stator magnetic isolation aluminum ring (62) and a stator yoke (63) are sequentially sleeved outside the axial stator (61).

2. The magnetic levitation flywheel energy storage device according to claim 1, wherein The sunken torsion stator (65) is a cuboid structure with the end warping downwards, and the left and right sides of the downward part of the end segment are hollowed out; a torsion coil (64) is wound around the middle part of the sunken torsion stator (65) along the circumferential direction.

3. The magnetic levitation flywheel energy storage device according to claim 1, wherein The "H + X" type magnetic pole (66) includes an X-type coil bracket (661), four corners of the X-type coil bracket (661) respectively extend out protruding poles outwards, radial permanent magnets (68) are also provided on the upper and lower sides of the X-type coil bracket (661), and a radial coil (69) is wound along the radial direction in the middle part of the X-type coil bracket (661).

4. The magnetic levitation flywheel energy storage device according to claim 1, wherein It further includes an energy absorption structure (3), the energy absorption structure (3) is composed of a plurality of energy absorption rings (31) coaxially combined at equal intervals along the axial direction, each energy absorption ring (31) is composed of a plurality of hollow energy absorption boxes (32) inserted at equal intervals along the circumferential direction on an energy absorption box base (311), and the energy absorption box base (311) is fixed inside the housing.

5. The magnetic levitation flywheel energy storage device according to claim 4, wherein, The waistline part of the energy absorption box (32) is provided with a guiding groove (321).

6. The magnetic levitation flywheel energy storage device according to claim 1, characterized in that, The flywheel main body (51), the narrow cylinder (511), the flywheel disc (512) and the flywheel short shaft (513) are all made of carbon fiber material.

7. The magnetic levitation flywheel energy storage device according to claim 1, characterized in that The permanent magnet patch ring (54) is alternately composed of a radial N - pole permanent magnet (541) and a radial S - pole permanent magnet (542).

8. The magnetic levitation flywheel energy storage device according to claim 1, wherein, The motor stator (4) is successively an A - phase stator (41), a B - phase stator (42) and a C - phase stator (43) in the clockwise direction.

9. The magnetic levitation flywheel energy storage device according to claim 1, wherein The housing further includes a cylindrical housing (21) and an upper end cover (11). The upper end of the cylindrical housing (21) is fixedly connected with the upper end cover (11), and the lower end is successively fixedly connected with a housing torsion permanent magnet (22), a first repulsive permanent magnet ring (24), a bottom cast iron ring (27) and a second repulsive permanent magnet ring (25).

10. The magnetic levitation flywheel energy storage device according to claim 9, characterized in that, The upper end cover (11) is provided with a central hole, and a plurality of wire routing holes (112) are arranged near the central hole, and two circles of heat dissipation holes (111) are arranged along the circumference and equi - axially away from the central hole.

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