Magnetic suspension flywheel energy storage system

Abstract

The invention provides a magnetic suspension flywheel energy storage system. The magnetic suspension flywheel energy storage system comprises a magnetic suspension bearing, a flywheel and a motor which are sequentially arranged from top to bottom. A magnetic bearing with five degrees of freedom is arranged at the upper end of a flywheel rotor, a stator at the upper end of the magnetic bearing is provided with four upper-layer stator teeth and four lower-layer stator teeth, the upper-layer stator teeth and the lower-layer stator teeth which are adjacent to each other in the circumferential direction are staggered by 45 degrees, and the difference between the upper-layer stator teeth and the lower-layer stator teeth which are adjacent to each other in the circumferential direction is 90 degrees; the upper-layer stator teeth and the lower-layer stator teeth are equal in size, and the pole shoe parts are large; the lower surface of each upper-layer stator tooth or each lower-layer stator tooth extends downwards to form an axial stator tooth, and the total number of the axial stator teeth is eight; each stator tooth is provided with a control coil; an axially magnetized annular magnetic bearing permanent magnet is arranged between the upper end stator and the lower end stator; the lower end stator is of an L-shaped ring-like structure and is used for fixing a magnetic bearing permanent magnet. The flywheel rotor five-degree-of-freedom control device realizes five-degree-of-freedom control of the flywheel rotor, and is simple in structure and easy to process and mount.

Description

Technical Field

[0001] The invention relates to the technical field of energy storage, and in particular to a magnetic suspension flywheel energy storage system. Background Art

[0002] In the magnetic levitation flywheel energy storage system, due to the effect of the magnetic bearing on the flywheel, not only the load imposed on the mechanical contact when the flywheel runs at high speed is eliminated, but also the friction loss caused by the mechanical contact is eliminated; it is beneficial to the energy storage of the flywheel energy storage system and prolongs the service life of the flywheel energy storage system; therefore, magnetic bearings have received widespread attention in flywheel energy storage applications.

[0003] However, in the current magnetic levitation flywheel energy storage system, most of them use a 3-DOF magnetic bearing and a 2-DOF magnetic bearing to match each other to achieve the suspension of the flywheel, but the number of magnetic bearings used is large, which is not conducive to the installation of the magnetic levitation flywheel energy storage system and also increases the manufacturing cost. The prior art also uses 5-DOF magnetic bearings to reduce the number of magnetic bearings, but the structure of the 5-DOF magnetic bearings currently used is relatively complex, and the rotor needs to have a protruding structure as a magnetic circuit, which raises higher requirements for the processing technology. Therefore, there is an urgent need for a magnetic bearing with 5 degrees of freedom and a simple structure to meet the requirements of stable suspension control of the flywheel. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] Based on this, the present invention provides a magnetic levitation flywheel energy storage system to solve the problem of a large number of magnetic bearings and a complex structure in the magnetic levitation flywheel energy storage system mentioned in the background technology.

[0006] (II) Technical solution

[0007] In order to achieve the above-mentioned object, the present invention provides a magnetic suspension flywheel energy storage system, comprising a magnetic bearing, a flywheel, a permanent magnet on the inner surface of the flywheel, a stator, and an armature winding; wherein the flywheel comprises a flywheel shaft and a flywheel rotor;

[0008] The magnetic bearing comprises an upper stator, a lower stator, a magnetic bearing permanent magnet, an axial control coil, an upper control coil, and a lower control coil;

[0009] The upper end stator is a symmetrical structure with the flywheel shaft as the central axis, comprising a stator yoke, upper stator teeth, lower stator teeth and axial stator teeth; the upper stator teeth and lower stator teeth are arranged in layers, 4 upper stator teeth are evenly distributed circumferentially in the upper layer, and 4 lower stator teeth are evenly distributed circumferentially in the lower layer; circumferentially adjacent upper stator teeth and lower stator teeth are staggered 45 degrees with each other; circumferentially adjacent upper stator teeth and circumferentially adjacent lower stator teeth are 90 degrees apart; the upper stator teeth and lower stator teeth are equal in size, and the inner surfaces of the two close to the flywheel shaft have air gaps with the flywheel shaft; the upper stator teeth and the lower stator teeth are axially spaced a certain distance apart;

[0010] An axial stator tooth extends downward from the lower surface of each upper stator tooth or lower stator tooth, with a total of 8 axial stator teeth, and an air gap is provided between the lower surface of the axial stator tooth and the upper end surface of the flywheel rotor;

[0011] The upper stator teeth, the lower stator teeth and the axial stator teeth are respectively wound with an upper control coil, a lower control coil and an axial control coil.

[0012] Furthermore, the pole shoe portions of the upper stator teeth and the lower stator teeth are relatively large, and the sum of the pole shoe radians of the four upper stator teeth or the four lower stator teeth is approximately equal to 2π.

[0013] Furthermore, the magnetic bearing permanent magnet is an axially magnetized annular permanent magnet, and is located between the upper stator and the lower stator.

[0014] Furthermore, the lower end stator is an L-shaped ring-like structure, which is convenient for placing the magnetic bearing permanent magnet; there is an air gap between the lower end surface of the lower end stator and the upper end surface of the flywheel rotor.

[0015] Furthermore, the flywheel rotor is a circular ring structure as a whole, and a coaxial annular groove is processed on the lower end surface of the flywheel rotor. The annular groove divides the lower section of the flywheel rotor into a flywheel rotor inner ring and a flywheel rotor outer ring. The inner surface of the flywheel rotor outer ring is affixed with a flywheel inner surface permanent magnet; a stator is placed between the flywheel rotor inner ring and the flywheel rotor outer ring, and there is an air gap between the stator and the flywheel rotor, and they do not contact each other.

[0016] Furthermore, the stator is made of a non-magnetic and non-conductive material.

[0017] Furthermore, the area of ​​the flywheel corresponding to the magnetic bearing where the magnetic flux flows in and out is made of silicon steel material, and the other areas are made of high-strength structural steel material.

[0018] (III) Beneficial effects

[0019] It can be seen from the above technical solution that the magnetic levitation flywheel energy storage system proposed by the present invention has the following beneficial effects:

[0020] 1. It adopts five-degree-of-freedom magnetic bearings with simple structure and is easy to process and install.

[0021] 2. In the upper stator part, the sum of the pole shoe radians of the same layer of stator teeth (4 upper stator teeth or 4 lower stator teeth) is approximately equal to 2π. By increasing the pole shoe radian, the core loss generated by the flywheel is reduced.

[0022] 3. In the flywheel, the areas corresponding to the upper stator teeth, the inner surface of the lower stator teeth and the lower surface of the axial stator teeth are made of silicon steel sheet material, and the remaining parts are made of high-strength structural steel material, which reduces the core loss generated by the flywheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the present invention in any way. In the accompanying drawings:

[0024] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0025] Figure 2 It is a schematic diagram of the structure explosion of an embodiment of the present invention;

[0026] Figure 3 is a cross-sectional schematic diagram of a magnetic bearing according to an embodiment of the present invention;

[0027] Figure 4 is a cross-sectional schematic diagram of an embodiment of the present invention;

[0028] Figure 5 Schematic diagram of the magnetic flux path of the magnetic bearing according to an embodiment of the present invention.

[0029] Among them: 1. stator; 2. rotating shaft; 3. permanent magnet on the inner surface of the flywheel; 4. flywheel; 5. lower end stator; 6. permanent magnet of magnetic bearing; 7. axial control coil; 8. upper end stator; 8-1. upper stator teeth; 8-2. lower stator teeth; 8-3. axial stator teeth; 9. upper control coil; 10. lower control coil. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The magnetic suspension flywheel energy storage system of the present invention is as follows Figure 1-3 As shown, it includes a magnetic bearing, a flywheel, permanent magnets 3 on the inner surface of the flywheel, a stator 1, and an armature winding, wherein the flywheel includes a flywheel shaft 2 and a flywheel rotor 4.

[0032] like Figure 4 As shown, the flywheel rotor 4 is a circular ring structure as a whole, and a coaxial annular groove is processed on the lower end surface of the flywheel rotor 4. The annular groove divides the lower section of the flywheel rotor 4 into a flywheel rotor inner ring and a flywheel rotor outer ring, and the inner surface of the flywheel rotor outer ring is affixed with a flywheel inner surface permanent magnet 3. A stator 1 is placed between the flywheel rotor inner ring and the flywheel rotor outer ring. There is an air gap between the stator 1 and the flywheel rotor 4, and they do not contact each other. The stator 1 is made of non-magnetic and non-conductive materials such as ceramics and epoxy resins, and the armature winding is arranged in the stator 1. The armature winding, the stator 1 and the flywheel inner surface permanent magnet 3 are components of the motor. The motor and the flywheel are an integrated structure, and the flywheel energy storage system can be charged and discharged through the motor.

[0033] The flywheel shaft 2 passes through the flywheel rotor 4 and is tightly connected to the flywheel rotor 4. The flywheel corresponds to the area where the magnetic flux flows in and out of the magnetic bearing (such as Figure 5 The shaded area is made of silicon steel (easy to conduct magnetism), and other areas are made of high-strength structural steel.

[0034] The flywheel shaft 2 passes through the magnetic bearing, and the magnetic bearing is located above the flywheel rotor 4. The magnetic bearing includes an upper stator 8, a lower stator 5, a magnetic bearing permanent magnet 6, an axial control coil 7, an upper control coil 9, and a lower control coil 10.

[0035] like Figure 3 As shown, the upper end stator 5 is constructed of a whole piece of solid steel, and is symmetrically shaped with the flywheel shaft 2 as the central axis, including a stator yoke, an upper stator tooth 5-1, a lower stator tooth 5-2, and an axial stator tooth 5-3. The upper stator teeth 5-1 and the lower stator teeth 5-2 are arranged in layers, and the four upper stator teeth 5-1 are evenly distributed in the upper layer, and the four lower stator teeth 5-2 are evenly distributed in the lower layer; the circumferentially adjacent upper stator teeth 5-1 and lower stator teeth 5-2 are staggered 45 degrees with each other; the circumferentially adjacent upper stator teeth 5-1 and the circumferentially adjacent lower stator teeth 5-2 are 90 degrees apart. The upper stator teeth 5-1 and the lower stator teeth 5-2 are equal in size, and there is an air gap between the inner surface of the flywheel shaft 2 and the flywheel shaft 2. In the flywheel shaft 2, the area corresponding to the inner surface of the upper stator teeth 5-1 and the lower stator teeth 5-2 is made of silicon steel sheet material (see Figure 5The pole shoes of the upper stator teeth 5-1 and the lower stator teeth 5-2 are relatively large, and the sum of the pole shoe radians of the same layer of stator teeth (four upper stator teeth 5-1 or four lower stator teeth 5-2) is approximately equal to 2π. The upper stator teeth 5-1 and the lower stator teeth 5-2 are axially spaced a certain distance apart.

[0036] An axial stator tooth 5-3 extends downward from the lower surface of each upper stator tooth 5-1 (or lower stator tooth 5-2), and there are 8 axial stator teeth 5-3 in total. There is an air gap between the lower surface of the axial stator tooth 5-3 and the upper end surface of the flywheel rotor 4; and in the flywheel rotor 4, the area corresponding to the lower surface of the axial stator tooth 5-3 is made of silicon steel sheet material (see Figure 5 The upper stator teeth 5-1, the lower stator teeth 5-2 and the axial stator teeth 5-3 are respectively wound with the upper control coil 9, the lower control coil 10 and the axial control coil 7.

[0037] The magnetic bearing permanent magnet 6 is an axially magnetized annular permanent magnet, located between the upper stator 8 and the lower stator 5. The lower stator is an L-shaped annular structure, which is convenient for placing the magnetic bearing permanent magnet 6. There is an air gap between the lower end surface of the lower stator and the upper end surface of the flywheel rotor.

[0038] like Figure 5 As shown, the bias magnetic flux generated by the magnetic bearing permanent magnet 6 is generally represented by solid lines and arrows. There are three bias magnetic flux paths. The first path mainly passes through the magnetic bearing permanent magnet 6, the upper stator 5, the upper stator teeth 5-1, the flywheel shaft 2, the flywheel rotor 4, the lower stator 5, and finally returns to the magnetic bearing permanent magnet 6; the second path mainly passes through the magnetic bearing permanent magnet 6, the upper stator 5, the lower stator teeth 5-2, the flywheel shaft 2, the flywheel rotor 4, the lower stator 5, and finally returns to the magnetic bearing permanent magnet 6; the third path mainly passes through the magnetic bearing permanent magnet 6, the upper stator 5, the axial stator teeth 5-3, the flywheel rotor 4, the lower stator 5, and finally returns to the magnetic bearing permanent magnet 6. When the flywheel is in the central equilibrium position, the central axis of the flywheel coincides with the central axis of the magnetic bearing.

[0039] By adjusting the control coil current on each stator tooth (upper stator teeth, lower stator teeth and axial stator teeth), the air gap flux corresponding to each stator tooth is controlled, so as to achieve the purpose of adjusting the size of the electromagnetic force. By controlling the air gap flux corresponding to the upper stator teeth and the lower stator teeth, the flywheel rotor can be controlled in the x-direction translation, y-direction translation, rotation around the x-axis and rotation around the y-axis, and the radial two degrees of freedom and torsional two degrees of freedom of the flywheel rotor can be balanced. The flywheel energy storage system belongs to a vertical flywheel energy storage system. The flywheel rotor is subjected to gravity load. The electromagnetic force generated by controlling the axial control coil current offsets the gravity, so that the flywheel rotor is axially stably suspended, and the axial single degree of freedom of the flywheel rotor is balanced.

[0040] It can be seen from the above that the present invention realizes the control of the five degrees of freedom of the flywheel rotor, and has a simple structure and is easy to process and install.

[0041] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A magnetic levitation flywheel energy storage system, characterized in that: It includes a magnetic bearing, a flywheel, a permanent magnet on the inner surface of the flywheel, a stator, and an armature winding; wherein the flywheel includes a flywheel shaft and a flywheel rotor; The magnetic bearing comprises an upper stator, a lower stator, a magnetic bearing permanent magnet, an axial control coil, an upper control coil, and a lower control coil; The upper end stator is a symmetrical structure with the flywheel shaft as the central axis, comprising a stator yoke, upper stator teeth, lower stator teeth and axial stator teeth; the upper stator teeth and lower stator teeth are arranged in layers, 4 upper stator teeth are evenly distributed circumferentially in the upper layer, and 4 lower stator teeth are evenly distributed circumferentially in the lower layer; circumferentially adjacent upper stator teeth and lower stator teeth are staggered 45 degrees with each other; circumferentially adjacent upper stator teeth and circumferentially adjacent lower stator teeth are 90 degrees apart; the upper stator teeth and lower stator teeth are equal in size, and the inner surfaces of the two close to the flywheel shaft have air gaps with the flywheel shaft; the upper stator teeth and the lower stator teeth are axially spaced a certain distance apart; An axial stator tooth extends downward from the lower surface of each upper stator tooth or lower stator tooth, with a total of 8 axial stator teeth, and an air gap is provided between the lower surface of the axial stator tooth and the upper end surface of the flywheel rotor; The upper stator teeth, the lower stator teeth and the axial stator teeth are respectively wound with an upper control coil, a lower control coil and an axial control coil.

2. The system according to claim 1, characterized in that The pole shoe parts of the upper stator teeth and the lower stator teeth are relatively large, and the sum of the pole shoe radians of the four upper stator teeth or the four lower stator teeth is approximately equal to 2π.

3. The system according to claim 1, characterized in that The magnetic bearing permanent magnet is an axially magnetized annular permanent magnet, and is located between the upper stator and the lower stator.

4. The system according to claim 1, characterized in that The lower end stator is an L-shaped ring-like structure, which is convenient for placing the magnetic bearing permanent magnet; there is an air gap between the lower end surface of the lower end stator and the upper end surface of the flywheel rotor.

5. The system according to claim 1, characterized in that The flywheel rotor is a circular ring structure as a whole, and a coaxial annular groove is processed on the lower end surface of the flywheel rotor. The annular groove divides the lower section of the flywheel rotor into a flywheel rotor inner ring and a flywheel rotor outer ring. The inner surface of the flywheel rotor outer ring is affixed with a flywheel inner surface permanent magnet; a stator is placed between the flywheel rotor inner ring and the flywheel rotor outer ring, and there is an air gap between the stator and the flywheel rotor, and they do not contact each other.

6. The system according to claim 5, characterized in that The stator is made of non-magnetic and non-conductive materials.

7. The system according to claim 1, characterized in that The flywheel is made of silicon steel in the area corresponding to the magnetic bearing where the magnetic flux flows in and out, and the other areas are made of high-strength structural steel.

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