Clutch type magnetic suspension flywheel energy storage system

Abstract

The application relates to the technical field of electric power energy storage, in particular to a clutch type magnetic suspension flywheel energy storage system, which comprises an axial flux motor, a flywheel rotor, a radial magnetic suspension bearing structure and an axial magnetic suspension bearing structure; the flywheel rotor and the axial flux motor are located in the middle part of the energy storage system, and the axial flux motor is an axial flux stator coreless motor; the axial magnetic suspension bearing structure comprises a plurality of axial magnetic suspension bearings, and each axial magnetic suspension bearing is internally provided with an axial magnetic suspension bearing winding; the radial magnetic suspension bearing structure comprises a plurality of radial magnetic suspension bearings which are uniformly arranged in the circumferential direction of the flywheel rotor, and each radial magnetic suspension bearing is internally provided with a radial magnetic suspension bearing winding. The clutch type magnetic suspension flywheel energy storage system provided by the application is not coupled with the magnetic field generated by the motor, and the magnetic fields generated by the radial magnetic bearing and the axial magnetic bearing are not coupled with each other, so that the stable suspension of the flywheel rotor and the high-efficiency energy conversion of the motor are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power storage, in particular to a clutch type magnetic suspension flywheel energy storage system. BACKGROUND

[0002] Flywheel energy storage system (FESS) is a device that stores and releases kinetic energy by using a high-speed rotating flywheel. This system converts electrical energy into mechanical energy through a motor / generator combination and stores it in a high-speed rotating flywheel. When electrical energy is needed, the system converts this stored mechanical energy back into electrical energy. Magnetic suspension flywheel energy storage system refers to using magnetic suspension bearings as the supporting components of the flywheel rotor in the energy storage system to achieve the suspension of the flywheel rotor, thereby reducing the energy loss of the flywheel rotor during rotation and improving the service life and energy storage capacity of the energy storage system.

[0003] The support form of the flywheel rotor in the flywheel energy storage system is mainly through mechanical bearings and magnetic suspension bearings. Magnetic suspension bearings are devices that use magnetic force to achieve bearing support function. Compared with ordinary mechanical bearings, magnetic bearings can make the rotor rotate without physical contact. This bearing forms a non-contact suspension state between the rotor and the stator through electromagnetic force or permanent magnetic force, thereby avoiding friction and wear and improving the operating efficiency and reliability of the system. Magnetic suspension bearings are mainly divided into two categories in practical application: radial magnetic suspension bearings and axial magnetic suspension bearings.

[0004] Magnetic suspension flywheel energy storage systems require the use of radial magnetic suspension bearings and axial magnetic suspension bearings to achieve the suspension of the flywheel rotor without contact with the outer wall in the radial and axial directions. In addition, the system also includes a motor to achieve energy conversion. There are various types of motors applied in energy storage systems, but for scenarios with limited axial size, axial flux motors are usually used to reduce the axial size of the system.

[0005] To further reduce the axial size of the system, one way is to design the magnetic bearing and the motor as a whole, which simultaneously achieves suspension and driving functions. However, due to the coupling of the magnetic fields of the two, the stability of the suspension and the energy conversion efficiency of the motor are affected. Another way is to completely separate the magnetic bearing and the motor, and install the magnetic bearing at both ends of the rotor shaft. This design can bring better suspension effect, but it occupies axial space. SUMMARY

[0006] The present application provides a clutch type magnetic suspension flywheel energy storage system, in which the magnetic fields generated by the radial magnetic bearing and the axial magnetic bearing are not coupled with the magnetic field generated by the motor, and the two are not coupled with each other, to achieve stable suspension of the flywheel rotor and efficient energy conversion of the motor.

[0007] To solve the above technical problems, the embodiment of the present application provides a clutch type magnetic suspension flywheel energy storage system, comprising: an axial flux motor, a flywheel rotor, a radial magnetic suspension bearing structure and an axial magnetic suspension bearing structure; wherein the flywheel rotor and the axial flux motor are located in the middle part of the energy storage system; the axial flux motor is an axial flux stator coreless motor, and the axial flux motor is used for generating a driving magnetic field and generating an induced current through magnetic induction phenomenon to realize energy conversion; the axial magnetic suspension bearing structure comprises a plurality of axial magnetic suspension bearings located in the axial direction of the flywheel rotor, and each axial magnetic suspension bearing is provided with an axial magnetic suspension bearing winding; the radial magnetic suspension bearing structure comprises a plurality of radial magnetic suspension bearings uniformly arranged in the circumferential direction of the flywheel rotor, and each radial magnetic suspension bearing is provided with a radial magnetic suspension bearing winding.

[0008] In some example embodiments, the axial flux motor comprises: a motor stator and a motor rotor, the motor rotor comprising a first rotor and a second rotor, wherein the motor stator is fixed to the middle part of the energy storage system through a motor support, and the motor stator is provided with a stator winding; the first rotor and the second rotor are respectively located on the two sides of the axial direction of the motor stator, and the first rotor and the second rotor are connected through a flywheel shaft located in the middle part of the energy storage system; the first rotor and the second rotor are both provided with a permanent magnet array composed of a plurality of permanent magnets, and the magnetic poles of the permanent magnets in each permanent magnet array are alternately arranged.

[0009] In some example embodiments, the magnetic circuit of the axial flux motor is: the magnetic field is emitted from the N pole of the permanent magnet of the first rotor, passes through the stator winding, flows into the S pole of the permanent magnet of the second rotor; then flows to the N pole of the permanent magnet of the second rotor through the ferromagnetic material of the second rotor; then flows out from the N pole of the permanent magnet of the second rotor, passes through the motor stator to the S pole of the permanent magnet of the first rotor, and then flows through the ferromagnetic material of the first rotor to flow back to the N pole of the first rotor, forming a closed loop of the magnetic circuit.

[0010] In some example embodiments, the axial magnetic suspension bearing structure comprises two thrust disc type axial magnetic suspension bearings; the two thrust disc type axial magnetic suspension bearings are respectively located on the two sides of the axial direction of the flywheel rotor; the axial displacement of the motor rotor is controlled by controlling the current in the axial magnetic suspension bearing winding.

[0011] In some example embodiments, the axial magnetic suspension bearing is further provided with a biasing permanent magnet and a coil winding, and the coil winding is arranged on the two sides of the axial direction of the flywheel shaft.

[0012] In some example embodiments, each axial magnetic suspension bearing is provided with an annular coil winding.

[0013] In some example embodiments, the radial magnetic suspension bearing structure comprises a plurality of groups of radial magnetic suspension bearing units arranged uniformly in the circumferential direction of the flywheel rotor; the radial displacement of the motor rotor is controlled by controlling the current in the radial magnetic suspension bearing winding; each group of radial magnetic suspension bearing units comprises a first radial magnetic bearing and a second radial magnetic bearing; the magnetic circuit of the radial magnetic suspension bearing unit is as follows: the magnetic field flows from the first radial magnetic bearing into the ferromagnetic material of the first rotor, then flows into the second radial magnetic bearing, and then flows from the second radial magnetic bearing into the second rotor, and then flows back to the first radial magnetic bearing through the ferromagnetic material of the second rotor, forming a closed loop of the magnetic circuit.

[0014] In some example embodiments, the first rotor and the second rotor are both disc-shaped rotors, and the materials of the first rotor and the second rotor are both ferromagnetic materials.

[0015] In some example embodiments, the axial flux motor further comprises: a motor support for carrying the motor stator and the stator winding; the motor stator comprises a plurality of stator winding blocks arranged uniformly in the circumferential direction of the motor support; the stator winding blocks are separated from the magnetic field of the motor rotor during energy storage, so as to realize the clutching of the motor rotor and the motor stator, thereby reducing the energy storage loss.

[0016] In some example embodiments, the above clutching type magnetic suspension flywheel energy storage system further comprises: a magnetic bearing platform for fixing the corresponding magnetic bearing teeth of the motor rotor; the magnetic bearing platform comprises a first magnetic bearing platform and a second magnetic bearing platform, and the first magnetic bearing platform and the second magnetic bearing platform are connected through a set of reversible screw threads; when the reversible screw threads rotate, the threads on the magnetic bearing platform will push the first magnetic bearing platform and the second magnetic bearing platform away from or close to each other according to the rotation of the screw threads.

[0017] The technical solutions provided in the present application have at least the following advantages:

[0018] The application provides a clutch type magnetic suspension flywheel energy storage system, comprising: an axial flux motor, a flywheel rotor, a radial magnetic suspension bearing structure and an axial magnetic suspension bearing structure; wherein the flywheel rotor and the axial flux motor are located in the middle part of the energy storage system; the axial flux motor is an axial flux stator coreless motor, and is used for generating a driving magnetic field and generating an induced current through magnetic induction to realize energy conversion; the axial magnetic suspension bearing structure comprises a plurality of axial magnetic suspension bearings located in the axial direction of the flywheel rotor, and each axial magnetic suspension bearing is internally provided with an axial magnetic suspension bearing winding; the radial magnetic suspension bearing structure comprises a plurality of radial magnetic suspension bearings which are uniformly arranged in the circumferential direction of the flywheel rotor, and each radial magnetic suspension bearing is provided with a radial magnetic suspension bearing winding. The application proposes a new type of magnetic suspension flywheel energy storage system which is decoupled in axial and radial bearing magnetic circuits and in which the magnetic fields of the magnetic bearings and the motor are not coupled with each other, so as to realize the characteristics of compact structure, short axial size and simple flywheel rotor structure. Moreover, the application proposes a clutch type flywheel energy storage scheme, which can effectively reduce energy storage loss. BRIEF DESCRIPTION OF DRAWINGS

[0019] One or more embodiments are illustrated by way of example in the figures that are part of this disclosure and which are illustrative, but not restrictive, of the present embodiments, unless otherwise specified, the figures in the drawings do not constitute a proportional limitation.

[0020] Figure 1 A structure schematic diagram of a clutch type magnetic suspension flywheel energy storage system provided by an embodiment of the application;

[0021] Figure 2 A magnetic circuit structure schematic diagram of an axial flux motor provided by an embodiment of the application;

[0022] Figure 3 A structure schematic diagram of an axial flux motor provided by an embodiment of the application;

[0023] Figure 4 A structure schematic diagram of a magnetic pole arrangement of a second rotor permanent magnet array provided by an embodiment of the application;

[0024] Figure 5 A sectional view of a clutch type magnetic suspension flywheel energy storage system provided by an embodiment of the application;

[0025] Figure 6 A magnetic circuit structure schematic diagram of a thrust disc type axial magnetic suspension bearing with permanent magnet magnetic field bias provided by an embodiment of the application;

[0026] Figure 7 A magnetic circuit structure schematic diagram of a thrust disc type axial magnetic suspension bearing without permanent magnet magnetic field bias provided by an embodiment of the application;

[0027] Figure 8 A structural schematic diagram of a radial magnetic suspension bearing magnetic circuit provided by an embodiment of the present application is shown in the figure.

[0028] Figure 9 A structural schematic diagram of a combined radial and axial magnetic suspension bearing magnetic circuit provided by an embodiment of the present application is shown in the figure.

[0029] Figure 10 A structural schematic diagram of a flywheel energy storage system in a motor energy conversion state and a clutch energy storage state provided by an embodiment of the present application is shown in the figure.

[0030] Figure 11 A structural schematic diagram of a flywheel energy storage system in a motor energy conversion state provided by another embodiment of the present application is shown in the figure.

[0031] Figure 12 A structural schematic diagram of a flywheel energy storage system in a clutch energy storage state provided by another embodiment of the present application is shown in the figure.

[0032] In the figure, 1 is an axial flux motor, 101 is a motor stator, 102 is a first rotor, 103 is a first rotor permanent magnet array, 1031 is a first rotor permanent magnet, 104 is a second rotor, 105 is a second rotor permanent magnet array, 1051 is a second rotor permanent magnet, 2 is a flywheel rotor, 201 is a flywheel shaft, 3 is a radial magnetic suspension bearing, 301 is a radial magnetic suspension bearing winding, 302 is a rotor silicon steel ring, 4 is an axial magnetic suspension bearing, 401 is an axial magnetic suspension bearing winding, 402 is an axial flux motor winding, 403 is a protection bearing, 5 is a bias permanent magnet, 6 is a coil winding, 311 is a first radial magnetic bearing, 312 is a second radial magnetic bearing, 313 is a motor support, 314 is a stator winding block, 315 is a radial magnetic bearing tooth, 411 is a first axial magnetic bearing, 412 is a second axial magnetic bearing, 413 is a positive and negative toothed screw, 414 is a first magnetic bearing platform, 415 is a second magnetic bearing platform, and D is a maximum extension distance. DETAILED DESCRIPTION

[0033] As can be seen from the background, the existing scheme for reducing the axial size of the system has the technical problems of occupying axial space, affecting the stability of suspension, and affecting the conversion efficiency of motor energy.

[0034] Both magnetic suspension bearing and motor achieve their respective functions by generating magnetic field. The magnetic bearing generates suspension magnetic field, and the motor generates driving magnetic field. In the existing design scheme for reducing the axial size of the system, for the design of the magnetic bearing and the motor, one scheme is to design the magnetic bearing and the motor into one (magnetic suspension flat sheet motor) to realize the functions of suspension and driving at the same time, so as to reduce the axial size of the energy storage system, and to decouple the control of the two through algorithm. However, when the suspension magnetic field and the driving magnetic field of the energy storage system are coupled together, the stability of the magnetic suspension and the energy conversion efficiency of the motor are affected, which increases the risk of instability of the flywheel rotor.

[0035] Another design scheme for reducing the axial size of the system is to completely separate the magnetic bearing and the motor, and to design two radial magnetic bearings and one thrust axial magnetic bearing at the upper and lower ends of the flywheel rotor axis. The electromagnetic force of the magnetic bearing will act on the rotor shaft instead of the rotor. Such design can bring more stable radial and axial suspension, but it occupies the axial size, which weakens the flatness of the energy storage system and limits the specific application.

[0036] A flywheel energy storage device with balanced features is designed in a related patent, which adopts a relatively complex magnetic circuit design on the sheet rotor, and proposes "H+X magnetic pole" to ensure the integration, energy storage performance and system loss of the energy storage device. However, this technology has a relatively complex magnetic circuit design, the magnetic circuit has multiple couplings, the flywheel rotor has a small volume, the precision requirement for the rotor processing is high, and the cost is high. Another related technology proposes a magnetic suspension flywheel energy storage device of integrated flywheel, which integrates the axial and radial magnetic suspension into one, and separates from the motor to realize the functions of suspension and energy storage, with the characteristics of small volume and high energy density. However, in this technology, the integrated design of the axial magnetic bearing and the radial magnetic bearing has magnetic circuit coupling, which affects the suspension effect, and the separation design of the magnetic bearing and the motor makes the axial size of the system large, which limits its application scenarios.

[0037] In view of the problems of the existing magnetic suspension flywheel energy storage system, such as large axial size, magnetic coupling and difficult control, a new type of magnetic suspension flywheel energy storage system with compact structure and short axial size is provided to realize stable suspension of the flywheel rotor and efficient energy conversion of the motor without affecting the axial size of the system. The system comprises an axial flux motor, a flywheel rotor, a radial magnetic suspension bearing structure and an axial magnetic suspension bearing structure. The flywheel rotor and the axial flux motor are located in the middle of the energy storage system. The axial flux motor is an axial flux stator coreless motor, which is used to generate a driving magnetic field and induce current through magnetic induction to realize energy conversion. The axial magnetic suspension bearing structure comprises a plurality of axial magnetic suspension bearings located in the axial direction of the flywheel rotor, and each axial magnetic suspension bearing is provided with an axial magnetic suspension bearing winding. The radial magnetic suspension bearing structure comprises a plurality of radial magnetic suspension bearings uniformly arranged in the circumferential direction of the flywheel rotor, and each radial magnetic suspension bearing is provided with a radial magnetic suspension bearing winding. The clutch type magnetic suspension flywheel energy storage system provided by the application is not coupled with the magnetic field generated by the motor, and the two are not coupled with each other, so as to realize stable suspension of the flywheel rotor and meet the requirement of the axial size limitation of the system in the application scenario.

[0038] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art can understand that in the embodiments of the present application, many technical details are proposed to enable the reader to better understand the present application. However, the technical solutions claimed by the present application can be realized even without these technical details and various changes and modifications based on the following embodiments.

[0039] Reference Figure 1 The embodiment of the present application provides a clutch type magnetic suspension flywheel energy storage system, which comprises an axial flux motor 1, a flywheel rotor 2, a radial magnetic suspension bearing structure and an axial magnetic suspension bearing structure. The flywheel rotor 2 and the axial flux motor 1 are located in the middle of the energy storage system. The axial flux motor 1 is an axial flux stator coreless motor, which is used to generate a driving magnetic field and induce current through magnetic induction to realize energy conversion. The axial magnetic suspension bearing structure comprises a plurality of axial magnetic suspension bearings 4 located in the axial direction of the flywheel rotor 2, and each axial magnetic suspension bearing 4 is provided with an axial magnetic suspension bearing winding. The radial magnetic suspension bearing structure comprises a plurality of radial magnetic suspension bearings 3 uniformly arranged in the circumferential direction of the flywheel rotor 2, and each radial magnetic suspension bearing 3 is provided with a radial magnetic suspension bearing winding.

[0040] The embodiment of the present application provides a clutch type magnetic suspension flywheel energy storage system, and the overall structure of the flywheel energy storage is as follows Figure 1As shown, the clutch type magnetic suspension flywheel energy storage system includes an axial flux motor 1, a flywheel rotor 2, a radial magnetic suspension bearing 3 and an axial magnetic suspension bearing 4. The axial flux motor 1 of the present application adopts an axial flux stator coreless motor with two-layer rotors as shown in Figure 2 The present application first proposes to use an axial flux stator coreless motor in a flywheel energy storage system to generate a driving magnetic field, which simultaneously realizes the functions of suspension and driving together with the three-dimensional suspension magnetic field generated by the magnetic bearing.

[0041] Figure 1 As shown, the core of the energy storage system is an axial flux motor 1, and the structure of the axial flux motor 1 is as shown in Figure 2 and Figure 3 The stator winding is wound by copper wire and fixed in a non-magnetic and non-conductive material (such as resin, plastic, etc.). Two disc-shaped rotors are symmetrically arranged on both sides of the motor stator 101, and a rotor silicon steel ring 302 is installed in the annular groove of the disc-shaped rotor. The rotor silicon steel ring 302 is a magnetically permeable material (such as silicon steel, iron, etc.), and a ring array of permanent magnets is fixed on each of the two disc-shaped rotors, and the magnetic poles of the permanent magnets in each array are alternately arranged (as shown in Figure 4

[0042] As shown in Figure 2 and Figure 3 In some embodiments, the axial flux motor 1 includes a motor stator 101 and a motor rotor, and the motor rotor includes a first rotor 102 and a second rotor 104. The motor stator 101 is fixed to the middle part of the energy storage system by a motor support 313, and the motor stator 101 is provided with a stator winding. The first rotor 102 and the second rotor 104 are located on both sides of the motor stator 101 in the axial direction, and the first rotor 102 and the second rotor 104 are connected by a flywheel shaft 201 located in the middle part of the energy storage system. The first rotor 102 and the second rotor 104 are each provided with a permanent magnet array composed of a plurality of permanent magnets, and the magnetic poles of the permanent magnets in each permanent magnet array are alternately arranged.

[0043] The magnetic poles of the first rotor permanent magnet 1031 and the second rotor permanent magnet 1051 are alternately arranged. Taking the second rotor permanent magnet 1051 as an example, Figure 4 a structure diagram of the magnetic pole arrangement of the second rotor permanent magnet array is shown; as shown in Figure 4 the magnetic poles of the second rotor permanent magnet 1051 are alternately arranged.

[0044] The magnetic circuit of the axial flux motor 1 is as shown in Figure 2 ​As indicated by the middle arrow, in some embodiments, the magnetic circuit of the axial flux motor 1 is as follows: the magnetic field originates from the N pole of the permanent magnet of the first rotor 102, passes through the stator winding, and flows into the S pole of the permanent magnet of the second rotor 104; then flows through the ferromagnetic material of the second rotor 104 to the N pole of the permanent magnet of the second rotor 104; then flows out from the N pole of the permanent magnet of the second rotor 104, passes through the motor stator 101 (stator core) to the S pole of the permanent magnet of the first rotor 102, then flows through the ferromagnetic material of the first rotor 102, and flows back to the N pole of the first rotor 102, forming a closed loop magnetic circuit. When the magnetic field passes through the stator winding, it reacts with the current in the winding to generate an armature reaction, thereby converting electrical energy into mechanical energy, or mechanical energy into electrical energy, thus realizing the charging and discharging of the flywheel system.

[0045] In some embodiments, the first rotor 102 and the second rotor 104 are both disc-shaped rotors, and the materials of the first rotor 102 and the second rotor 104 are both ferromagnetic materials.

[0046] like Figure 5 As shown, Figure 2 The motor stator 101 is fixed to the middle of the flywheel energy storage system of this application by a mechanical structure. The two rotors (first rotor 102 and second rotor 104) are located on both sides of the motor stator 101 and are connected by the flywheel shaft 201, so that the two rotors are fixed as a whole and will not generate relative rotation or relative axial movement.

[0047] Figure 5 This is a cross-sectional view of a clutch-type magnetic levitation flywheel energy storage system. (See also...) Figure 5The rotor silicon steel ring 302 and the radial magnetic suspension bearing 3 constitute a radial magnetic suspension magnetic circuit to realize the radial magnetic suspension function. The rotor permanent magnet 1031 and the rotor silicon steel ring 302 are both installed in the annular groove of the first rotor 102, and the first rotor 102 can be made of a material with weak magnetic conductivity (aluminum alloy). The first rotor 102 and the rotor silicon steel ring 302 are also used for energy storage. When the rotor rotates at a high speed under the driving of the armature reaction, the inertia of the rotor can store kinetic energy, thereby achieving the purpose of energy storage. When the rotor is braked under the armature reaction, the stored mechanical energy will be converted into electrical energy through the motor, thereby achieving the purpose of discharging. The axial magnetic suspension bearings 4 are arranged on both sides of the two rotors. The axial magnetic suspension bearings 4 can adopt a thrust disc type axial magnetic suspension bearing. By controlling the current in the axial magnetic bearing winding, the axial displacement of the rotor can be controlled. In the circumferential direction of the rotor, the radial magnetic suspension bearing 3 is arranged. By controlling the current in the magnetic bearing winding, the radial displacement of the rotor can be controlled. The rotor is in a sheet structure as a whole, so the radial magnetic bearing also plays a role in limiting the rotation of the rotor along the X-axis and the Y-axis, thereby realizing the full magnetic suspension function of the flywheel rotor. The gap between the protection bearing and the flywheel shaft is smaller than the air gap between the magnetic bearing and the flywheel rotor, so it can play a role in protecting the flywheel rotor and the shell from friction and collision when the magnetic suspension function fails or the energy storage system is closed.

[0048] It should be noted that the motor rotor and the flywheel rotor described in the above embodiments are integrated structures, which can be collectively referred to as a flywheel rotor.

[0049] In some embodiments, the axial magnetic suspension bearing structure includes two thrust disc type axial magnetic suspension bearings; the two thrust disc type axial magnetic suspension bearings are respectively located on the two sides of the flywheel rotor 2 in the axial direction; and the axial displacement of the motor rotor is controlled by controlling the current in the axial magnetic suspension bearing winding.

[0050] In some embodiments, the axial magnetic suspension bearing 4 is further provided with a biasing permanent magnet 5 and a coil winding 6, and the coil winding 6 is arranged on the two sides of the flywheel shaft 201 in the axial direction. The thrust disc type axial magnetic suspension bearing magnetic circuit scheme includes but is not limited to as shown in Figures 6 to 7 Figure 6 The axial magnetic bearing scheme with a permanent magnet magnetic field bias, and the arrow is the magnetic path direction.

[0051] In some embodiments, each axial magnetic suspension bearing 4 is provided with an annular coil winding. Figure 7 The axial magnetic bearing scheme without a permanent magnet magnetic field bias, and the arrow is the magnetic path direction. In Figure 7 , the axial magnetic suspension bearing 4 is a thrust type axial magnetic suspension bearing, and the coil winding 6 is an annular coil winding.

[0052] ​In some embodiments, the radial magnetic bearing structure includes multiple sets of radial magnetic bearing units evenly arranged in the circumferential direction of the flywheel rotor; the radial displacement of the motor rotor is controlled by controlling the current in the radial magnetic bearing windings; each set of radial magnetic bearing units includes a first radial magnetic bearing 311 and a second radial magnetic bearing 312. Figure 8 A schematic diagram of a radial magnetic levitation bearing structure, comprising four sets of radial magnetic levitation bearing units, is shown. Figure 8 As shown, the magnetic circuit of the radial magnetic levitation bearing unit is as follows: the magnetic field flows from the first radial magnetic bearing 311 into the ferromagnetic material of the first rotor 102 (i.e., the rotor silicon steel ring 302 in the annular groove of the first rotor 102), then into the second radial magnetic bearing 312, and through the second radial magnetic bearing 312 into the ferromagnetic material of the second rotor 104 (i.e., the rotor silicon steel ring 302 in the annular groove of the second rotor 104), and then flows back to the first radial magnetic bearing 311 through the ferromagnetic material of the second rotor 104, forming a closed loop of magnetic circuit.

[0053] This application also proposes a magnetic circuit scheme that combines the aforementioned radial and axial magnetic bearings, such as... Figure 9 As shown. By adjusting Figure 9 Each coil winding has 6 coils, which can simultaneously adjust the radial and axial electromagnetic forces of the bearing.

[0054] By comparison Figure 2 , Figures 6 to 9 It can be observed that the magnetic circuits of the energy storage system motor, radial magnetic bearing, and axial magnetic bearing are independent of each other and do not interfere with each other.

[0055] The biggest problem with flywheel energy storage compared to electrochemical energy storage is its shorter storage time. Because existing flywheel energy storage systems still experience rapid cutting of magnetic field lines during energy storage, leading to winding and core losses, the storage time is shorter than that of battery energy storage. Figure 2 As shown, when the rotor rotates at high speed, the magnetic field cuts the stator coils, generating losses. To address these issues, this application also proposes a clutch-type flywheel energy storage mechanism, which can effectively reduce flywheel energy storage losses and increase energy storage time. This application proposes a clutch-type flywheel energy storage structure, such as... Figure 10 As shown.

[0056] like Figure 10 As shown, in some embodiments, the axial flux motor 1 further includes: a motor bracket 313 for supporting the motor stator 101 and stator windings; the motor stator 101 includes multiple stator winding blocks 314 evenly arranged in the circumferential direction of the motor bracket 313; as shown Figure 10 As shown, by dividing the stator winding into blocks (stator winding block 314), during energy storage, the stator winding block 314 is removed from the magnetic field of the motor rotor to achieve the engagement and disengagement of the motor rotor and the motor stator 101, thereby reducing energy storage loss. Figure 10In the middle, the left figure is the structure of the clutch type flywheel energy storage system in the motor energy conversion state, and the right figure is the structure of the clutch type flywheel energy storage system in the clutch energy storage state.

[0057] As shown in Figure 11 and Figure 12 shown, in some embodiments, the above-mentioned clutch type magnetic suspension flywheel energy storage system further comprises: a magnetic bearing platform for fixing the corresponding magnetic bearing teeth of the motor rotor; the magnetic bearing platform comprises a first magnetic bearing platform 414 and a second magnetic bearing platform 415, and the first magnetic bearing platform 414 and the second magnetic bearing platform 415 are connected through a set of reversible screw rods 413; when the reversible screw rod 413 rotates, the threads on the magnetic bearing platform will push the first magnetic bearing platform 414 and the second magnetic bearing platform 415 away from or close to each other according to the rotation of the screw rod.

[0058] Figure 11 and Figure 12 respectively show the structure diagram of the clutch type flywheel energy storage system in the motor energy conversion state and the clutch energy storage state. As shown in Figure 11 and Figure 12 shown, the axial magnetic bearing teeth and the radial magnetic bearing teeth 315 corresponding to each rotor are respectively fixed on the magnetic bearing platform corresponding to each rotor. A set of reversible screw rods 413 are connected between the two magnetic bearing platforms. When the reversible screw rod 413 rotates, the threads on the magnetic bearing platform will push the two magnetic bearing platforms (the first magnetic bearing platform 414 and the second magnetic bearing platform 415) away from or close to each other according to the rotation of the screw rod. If the two platforms are away from each other, the magnetic bearings on the platforms will also attract the two rotors away from each other, thereby weakening the magnetic field between the rotors and reducing the stator loss. If the two platforms are close to each other, the magnetic bearings on the platforms will also attract the two rotors close to each other, thereby enhancing the magnetic field between the rotors, facilitating energy storage or energy release. Figure 12 In the middle, D is the maximum extension distance.

[0059] Compared with the prior art, the clutch type magnetic suspension flywheel energy storage system provided by the present application has the advantages that: the energy storage system is composed of an axial flux motor 1, a flywheel rotor 2, a radial magnetic suspension bearing 3 and an axial magnetic suspension bearing 4. For the design of the radial magnetic suspension bearing 3 and the axial magnetic suspension bearing 4, a three-dimensional magnetic circuit and a thrust disc form are respectively adopted to generate more stable suspension force. Moreover, the magnetic fields generated by the radial magnetic suspension bearing and the axial magnetic suspension bearing are not coupled with the magnetic field generated by the motor, and the two are not coupled with each other, avoiding mutual interference between the magnetic fields and affecting the stable suspension of the flywheel rotor and the efficient energy conversion of the motor. The structure design of the flywheel rotor is simple and easy to process, and at the same time, the structure design of the whole machine system is simple, compact and short in axial size, so as to meet the scene application of limited axial size.

[0060] The existing flywheel energy storage system based on permanent magnet motor cannot change the air gap magnetic field when the rotor rotates, so that large eddy current loss and hysteresis loss are generated, and the energy storage time is affected. In view of this problem, the clutch type mechanism is proposed, which can weaken the air gap magnetic field by changing the air gap length during energy storage, thereby reducing the eddy current loss and hysteresis loss, and delaying the energy storage time. That is, the clutch type magnetic suspension flywheel energy storage system changes the air gap length between the stator and the rotor to adjust the air gap magnetic field, thereby improving the energy storage time. Moreover, the finite element simulation and experimental verification are carried out, and the simulation results and experimental results prove that the scheme is feasible.

[0061] According to the above technical scheme, the clutch type magnetic suspension flywheel energy storage system is provided, which comprises: an axial flux motor 1, a flywheel rotor 2, a radial magnetic suspension bearing structure and an axial magnetic suspension bearing structure; wherein the flywheel rotor 2 and the axial flux motor 1 are located in the middle part of the energy storage system; the axial flux motor 1 is an axial flux stator coreless motor, and the axial flux motor 11 is used to generate a driving magnetic field and generate an induced current through magnetic induction phenomenon to realize energy conversion; the axial magnetic suspension bearing structure comprises a plurality of axial magnetic suspension bearings 4 located in the axial direction of the flywheel rotor 2, and each axial magnetic suspension bearing 4 is provided with an axial magnetic suspension bearing winding; the radial magnetic suspension bearing structure comprises a plurality of radial magnetic suspension bearings 3 uniformly arranged in the circumferential direction of the flywheel rotor 2, and each radial magnetic suspension bearing 3 is provided with a radial magnetic suspension bearing winding. The present application proposes a new type of magnetic suspension flywheel energy storage system with axial and radial magnetic bearing magnetic circuit decoupling, and the magnetic bearing and the motor magnetic field are not coupled, aiming at the problems of complex magnetic circuit, mutual coupling of magnetic circuit, complex flywheel rotor structure difficult to process and the like in the magnetic suspension flywheel energy storage system, so as to realize the characteristics of compact structure, short axial size, simple flywheel rotor structure and the like. Moreover, the clutch type flywheel energy storage scheme is proposed, which can effectively reduce the energy storage loss.

[0062] Those skilled in the art can understand that the above embodiments are specific embodiments for implementing the present application, and in actual application, various changes can be made in form and details without departing from the spirit and scope of the present application. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, therefore the protection scope of the present application should be limited by the scope defined in the claims.

Claims

1. A magnetic levitation flywheel energy storage system of the clutching type, characterized in that, Comprise: Axial flux motor, flywheel rotor, radial magnetic suspension bearing structure and axial magnetic suspension bearing structure; wherein, The flywheel rotor and the axial flux motor are located in the middle of the energy storage system; The axial flux motor is an axial flux stator coreless motor, and the axial flux motor is used for generating a driving magnetic field and generating an induced current through electromagnetic induction to realize energy conversion; The axial magnetic suspension bearing structure comprises a plurality of axial magnetic suspension bearings located in the axial direction of the flywheel rotor, and each axial magnetic suspension bearing is provided with an axial magnetic suspension bearing winding; The radial magnetic suspension bearing structure comprises a plurality of radial magnetic suspension bearings uniformly arranged in the circumferential direction of the flywheel rotor, and each radial magnetic suspension bearing is provided with a radial magnetic suspension bearing winding; The axial flux motor comprises a motor stator and a motor rotor, the motor rotor comprises a first rotor and a second rotor, wherein, The motor stator is fixed to the middle of the energy storage system through a motor support, and the motor stator is provided with a stator winding; The first rotor and the second rotor are respectively located on the two sides of the axial direction of the motor stator, and the first rotor and the second rotor are connected through a flywheel shaft located in the middle of the energy storage system; The first rotor and the second rotor are each provided with a permanent magnet array composed of a plurality of permanent magnets, and the magnetic poles of the permanent magnets in each permanent magnet array are alternately arranged; The radial magnetic suspension bearing structure comprises a plurality of radial magnetic suspension bearing units uniformly arranged in the circumferential direction of the flywheel rotor; the radial displacement of the motor rotor is controlled by controlling the current in the radial magnetic suspension bearing winding; Each group of radial magnetic suspension bearing units comprises a first radial magnetic bearing and a second radial magnetic bearing; the magnetic circuit of the radial magnetic suspension bearing unit is that the magnetic field flows from the first radial magnetic bearing into the ferromagnetic material of the first rotor, then flows into the second radial magnetic bearing, and then flows into the second rotor through the second radial magnetic bearing, and then flows back to the first radial magnetic bearing through the ferromagnetic material of the second rotor, forming a closed loop of the magnetic circuit.

2. The clutch-type magnetic flywheel energy storage system of claim 1, wherein, The magnetic circuit of the axial flux motor is that the magnetic field starts from the N pole of the permanent magnet of the first rotor, passes through the stator winding, flows into the S pole of the permanent magnet of the second rotor, then flows to the N pole of the permanent magnet of the second rotor through the ferromagnetic material of the second rotor, then flows out from the N pole of the permanent magnet of the second rotor, passes through the motor stator to the S pole of the permanent magnet of the first rotor, and then flows through the ferromagnetic material of the first rotor to flow back to the N pole of the first rotor, forming a closed loop of the magnetic circuit.

3. The clutch-type magnetic flywheel energy storage system of claim 1, wherein, The axial magnetic suspension bearing structure comprises two thrust disc type axial magnetic suspension bearings; the two thrust disc type axial magnetic suspension bearings are respectively located on the two sides of the axial direction of the flywheel rotor; The axial displacement of the motor rotor is controlled by controlling the current in the axial magnetic suspension bearing winding.

4. The clutch-type magnetic flywheel energy storage system of claim 3, wherein, The axial magnetic suspension bearing is further provided with a biasing permanent magnet and a coil winding, and the coil winding is arranged on the two sides of the axial direction of the flywheel shaft.

5. The clutch-type magnetic flywheel energy storage system of claim 3, wherein, Each axial magnetic suspension bearing is provided with an annular coil winding.

6. The clutch-type magnetic flywheel energy storage system of claim 1, wherein, The first rotor and the second rotor are both disc-shaped rotors, and the materials of the first rotor and the second rotor are both ferromagnetic materials.

7. The clutch-type magnetic flywheel energy storage system of claim 1, wherein, The axial flux motor further comprises a motor support for bearing the motor stator and the stator winding; The motor stator comprises a plurality of stator winding blocks uniformly arranged in the circumferential direction of the motor support; the stator winding blocks are separated from the motor rotor magnetic field during energy storage to realize the clutching of the motor rotor and the motor stator, thereby reducing the energy storage loss.

8. The clutch-type magnetic flywheel energy storage system of claim 1, wherein, Further comprising: A magnetic bearing platform for fixing the corresponding magnetic bearing teeth of the motor rotor; The magnetic bearing platform comprises a first magnetic bearing platform and a second magnetic bearing platform, and the first magnetic bearing platform and the second magnetic bearing platform are connected through a set of reversible screw rods; When the reversible screw rod rotates, the threads on the magnetic bearing platform will push the first magnetic bearing platform and the second magnetic bearing platform away from or close to each other according to the rotation of the screw rod.

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