A magnetic levitation flywheel energy storage system

Abstract

The application provides a magnetic suspension flywheel energy storage system, which comprises a magnetic suspension bearing, a flywheel and a motor arranged in sequence from top to bottom. The magnetic bearing with 5 degrees of freedom is arranged on the upper end of the flywheel rotor. The upper end stator of the magnetic bearing is provided with 4 upper layer stator teeth and 4 lower layer stator teeth. The circumferentially adjacent upper layer stator teeth and lower layer stator teeth are staggered by 45 degrees. The circumferentially adjacent upper layer stator teeth and lower layer stator teeth are staggered by 90 degrees. The upper layer stator teeth and the lower layer stator teeth are equal in size and large in pole shoe part. The lower surface of each upper layer stator tooth or lower layer stator tooth extends downward by an axial stator tooth, and there are totally 8 axial stator teeth. Each stator tooth is provided with a control coil. The axial magnetized annular magnetic bearing permanent magnet is arranged between the upper end stator and the lower end stator. The lower end stator is in the shape of L and is annular, which is used for fixing the magnetic bearing permanent magnet. The application realizes the control of the 5 degrees of freedom of the flywheel rotor, and is simple in structure and easy to process and install.

Description

TECHNICAL FIELD

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

[0002] In the magnetic suspension flywheel energy storage system, due to the action of the magnetic bearing on the flywheel, not only the load exerted by the flywheel on the mechanical contact during high-speed operation is eliminated, but also the friction loss generated 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, the magnetic bearing in the flywheel energy storage application has been widely concerned.

[0003] However, at present, in the magnetic suspension flywheel energy storage system, a 3-DOF magnetic bearing and a 2-DOF magnetic bearing are often used to realize the suspension of the flywheel, but the number of magnetic bearings used is large, which is not conducive to the installation of the magnetic suspension flywheel energy storage system and also increases the manufacturing cost. The prior art also uses a 5-DOF magnetic bearing to reduce the number of magnetic bearings, but the structure of the 5-DOF magnetic bearing is relatively complex, and the rotor needs to have a protruding structure as a magnetic circuit, which requires higher requirements for the processing technology, so there is an urgent need for a 5-DOF magnetic bearing with a simple structure to meet the requirements of stable suspension control of the flywheel. SUMMARY

[0004] (I) Technical problem to be solved

[0005] Therefore, the present application provides a magnetic suspension flywheel energy storage system to solve the problem of too many magnetic bearings and complex structure in the magnetic suspension flywheel energy storage system mentioned in the background.

[0006] (II) Technical scheme

[0007] In order to achieve the above purpose, the present application provides a magnetic suspension flywheel energy storage system, which comprises a magnetic bearing, a flywheel, a flywheel inner surface permanent magnet, a stator, and an armature winding; wherein the flywheel comprises a flywheel shaft and a flywheel rotor;

[0008] The magnetic bearing comprises an upper end stator, a lower end stator, a magnetic bearing permanent magnet, an axial control coil, an upper layer control coil, and a lower layer 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, with four upper stator teeth uniformly distributed circumferentially in the upper layer and four lower stator teeth uniformly 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 both 90 degrees apart; the upper stator teeth and lower stator teeth are of equal size, and an air gap exists between the inner surfaces of both close to the flywheel shaft and the flywheel shaft; the upper stator teeth and 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 and each lower stator tooth, with a total of eight axial stator teeth, and an air gap is formed 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, 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 non-magnetic and non-conductive materials.

[0017] Furthermore, 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.

[0018] (3) Beneficial effects

[0019] As can be seen from the above technical solution, 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 sheets, and the remaining parts are made of high-strength structural steel, 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 Schematic diagram of the structure of an embodiment of the present invention;

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

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

[0027] Figure 4 A schematic cross-sectional view 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 stator; 6. Permanent magnet of the magnetic bearing; 7. Axial control coil; 8. Upper 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] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0031] The magnetic suspension flywheel energy storage system of the present application, as shown in Figures 1-3 includes a magnetic bearing, a flywheel, a flywheel inner surface permanent magnet 3, a stator 1, and an armature winding, wherein the flywheel includes a flywheel shaft 2 and a flywheel rotor 4.

[0032] As shown in Figure 4 , the flywheel rotor 4 is a whole circular ring structure, and a coaxial annular groove is machined on the lower end surface of the flywheel rotor 4, which divides the lower section of the flywheel rotor 4 into a flywheel rotor inner ring and a flywheel rotor outer ring. The inner surface of the flywheel rotor outer ring is attached with the flywheel inner surface permanent magnet 3. The stator 1 is placed between the flywheel rotor inner ring and the flywheel rotor outer ring, and there is an air gap between the stator 1 and the flywheel rotor 4 without contact. The stator 1 is made of non-magnetic and non-conductive materials such as ceramic and epoxy resin, 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, and the motor and the flywheel are integrated structure. The motor can realize charging and discharging of the flywheel energy storage system.

[0033] The flywheel shaft 2 penetrates the flywheel rotor 4 and is tightly connected together with the flywheel rotor 4. The flywheel corresponding to the magnetic flux inflow and outflow area of the magnetic bearing (as shown in Figure 5 the shaded area) is made of silicon steel material (easy to magnetize), and other areas are made of high-strength structural steel material.

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

[0035] As shown in Figure 3 , the upper end stator 8 is made of a whole solid steel structure, which is a symmetrical structure with the flywheel shaft 2 as the center axis, and includes a stator yoke, an upper layer stator tooth 8-1, a lower layer stator tooth 8-2, and an axial stator tooth 8-3. The upper layer stator tooth 8-1 and the lower layer stator tooth 8-2 are arranged in layers, and four upper layer stator teeth 8-1 are evenly distributed in the upper layer, and four lower layer stator teeth 8-2 are evenly distributed in the lower layer. The circumferentially adjacent upper layer stator teeth 8-1 and lower layer stator teeth 8-2 are staggered by 45 degrees. The circumferentially adjacent upper layer stator teeth 8-1 and the circumferentially adjacent lower layer stator teeth 8-2 are staggered by 90 degrees. The upper layer stator tooth 8-1 and the lower layer stator tooth 8-2 are equal in size, and the inner surfaces of both close to the flywheel shaft 2 have an air gap with the flywheel shaft 2. The regions in the flywheel shaft 2 corresponding to the inner surfaces of the upper layer stator tooth 8-1 and the lower layer stator tooth 8-2 are made of silicon steel sheet material (see Figure 5The pole shoe parts of the upper stator teeth 8-1 and the lower stator teeth 8-2 are relatively large, and the sum of the pole shoe arc of the same layer stator teeth (4 upper stator teeth 8-1 or 4 lower stator teeth 8-2) is approximately equal to 2π, and the upper stator teeth 8-1 and the lower stator teeth 8-2 are axially separated by a certain distance.

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

[0037] The magnetic bearing permanent magnet 6 is an axially magnetized ring-shaped permanent magnet located between the upper end stator 8 and the lower end stator 5. The lower end stator is an L-shaped ring-like 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 end stator and the upper end surface of the flywheel rotor.

[0038] As shown in Figure 5 The bias magnetic flux generated by the magnetic bearing permanent magnet 6 is indicated by solid lines and arrows. There are three paths of bias magnetic flux. The first path mainly passes through the magnetic bearing permanent magnet 6, the upper end stator 8, the upper stator tooth 8-1, the flywheel shaft 2, the flywheel rotor 4, the lower end 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 end stator 8, the lower stator tooth 8-2, the flywheel shaft 2, the flywheel rotor 4, the lower end 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 end stator 5, the axial stator tooth 8-3, the flywheel rotor 4, the lower end 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] Adjusting the current of the control coils on each stator tooth (upper stator tooth, lower stator tooth and axial stator tooth) controls the corresponding air gap magnetic flux of each stator tooth, so as to achieve the purpose of adjusting the electromagnetic force. Controlling the air gap magnetic flux corresponding to the upper stator tooth and the lower stator tooth can realize the control of the flywheel rotor in the x direction, the y direction, the rotation around the x axis and the rotation around the y axis, and realize the balance of the flywheel rotor in the radial two degrees of freedom and the torsional two degrees of freedom. The flywheel energy storage system belongs to a vertical flywheel energy storage system, and the flywheel rotor is subjected to a gravitational load. By controlling the electromagnetic force generated by the axial control coil current to offset the gravity, the flywheel rotor is stably suspended in the axial direction, and the balance of the flywheel rotor in the axial single degree of freedom is realized.

[0040] From above, the application realizes the control of five degrees of freedom of the flywheel rotor, and has simple structure, easy processing and installation.

[0041] The above merely describes the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A magnetic levitation flywheel energy storage system, characterized in that: The invention comprises 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; The magnetic bearing includes 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, with four upper stator teeth uniformly distributed circumferentially in the upper layer and four lower stator teeth uniformly 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 both 90 degrees apart; the upper stator teeth and lower stator teeth are of equal size, and an air gap exists between the inner surfaces of both close to the flywheel shaft and the flywheel shaft; the upper stator teeth and 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 and each lower stator tooth, with a total of eight axial stator teeth, and an air gap is formed 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, wherein: 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.

3. The system according to claim 1, wherein: 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, wherein: 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, wherein: 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 an inner ring of the flywheel rotor and an outer ring of the flywheel rotor. The inner surface of the outer ring of the flywheel rotor is affixed with a flywheel inner surface permanent magnet; a stator is placed between the inner ring of the flywheel rotor and the outer ring of the flywheel rotor, 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, wherein: The flywheel is made of silicon steel in the area corresponding to the inflow and outflow of magnetic flux of the magnetic bearing, and the other areas are made of high-strength structural steel.

Images