Flywheel rotor with variable rotational inertia and flywheel energy storage system

Abstract

The invention belongs to the technical field of flywheel energy storage, and discloses a flywheel rotor with variable rotational inertia and a flywheel energy storage system.The flywheel rotor comprises a rotating shaft, and variable rotor units and fixed rotor units are arranged on the rotating shaft at intervals; the variable rotor unit comprises an annular magnet fixedly arranged on a rotating shaft in a sleeving mode, the rotating shaft is evenly connected with a plurality of upper sliding rods inclining upwards in the circumferential direction of the upper side of the annular magnet, and each upper sliding rod is sleeved with an upper moving sliding block and a first limiting structure for conducting upper limiting on the upper moving sliding block. The rotating shaft is uniformly connected with a plurality of downwards inclined lower sliding rods in the circumferential direction of the lower side of the annular magnet, and each lower sliding rod is sleeved with a lower sliding block and a second limiting structure for performing lower limiting on the lower sliding block; the annular magnet can attract the upward moving sliding block and the downward moving sliding block through magnetic force. According to the flywheel rotor with the variable rotational inertia, the structure is changed along with the change of the rotating speed, then the rotational inertia is changed, and therefore the flywheel rotor can well adapt to irregular changes of primary frequency modulation and secondary frequency modulation of a power grid.

Description

Technical Field

[0001] The invention belongs to the technical field of flywheel energy storage, and in particular relates to a flywheel rotor with variable moment of inertia and a flywheel energy storage system. Background Art

[0002] The flywheel energy storage system is an advanced physical energy storage technology that uses an electric motor to drive a flywheel to rotate at high speed to store energy, and releases energy when needed by driving a generator to generate electricity through the flywheel. The working principle of the flywheel energy storage system is based on the law of conservation of energy and the law of kinetic energy, and realizes the mutual conversion and storage between electrical energy and mechanical energy through a reciprocal bidirectional motor for electric and generating electricity.

[0003] The flywheel rotor is the core component of the flywheel energy storage system. The flywheel rotors with large capacity and power levels are mostly made of alloy steel to increase the single unit capacity and storage capacity. At present, the shape of the flywheel rotor is cylindrical, and the moment of inertia is stable during rotation, which cannot be flexibly adjusted and cannot adapt well to the irregular changes of primary and secondary frequency modulation of the power grid. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a flywheel rotor with variable rotational inertia and a flywheel energy storage system. The flywheel rotor with variable rotational inertia provided by the present invention changes its structure as the rotation speed changes, thereby changing the rotational inertia, so it can well adapt to the irregular changes of the primary frequency modulation and secondary frequency modulation of the power grid.

[0005] The present invention adopts the following technical solutions: A flywheel rotor with variable moment of inertia comprises a rotating shaft, on which a variable rotor unit with variable moment of inertia and a fixed rotor unit with fixed moment of inertia are arranged alternately; The variable rotor unit includes an annular magnet fixedly sleeved on the rotating shaft, and the rotating shaft is evenly connected to a plurality of upwardly inclined upper sliding rods on the upper side of the annular magnet in the circumferential direction, each upper sliding rod sleeve is provided with an upward sliding block that can slide along the upper sliding rod, and the upper sliding rod is provided with a first limiting structure for upper positioning of the upward sliding block; the rotating shaft is evenly connected to a plurality of downwardly inclined lower sliding rods on the lower side of the annular magnet in the circumferential direction, each lower sliding rod sleeve is provided with a downward sliding block that can slide along the downward sliding block, and the downward sliding rod is provided with a second limiting structure for lower positioning of the downward sliding block; the annular magnet can attract the upper sliding block and the lower sliding block by magnetic force.

[0006] Preferably, the lower end of the upper slide bar is fixedly connected to the rotating shaft, and the upper end of the upper slide bar passes through the annular magnet.

[0007] Preferably, in each variable rotor unit, the rotating shaft is evenly connected to 4 to 8 upper sliding bars in the circumferential direction on the upper side of the annular magnet.

[0008] Preferably, the angle between the axis of the upper slide bar and the axis of the rotating shaft is 45°~60°.

[0009] Preferably, the upper end of the lower slide bar is fixedly connected to the rotating shaft, and the lower end of the lower slide bar passes through the annular magnet.

[0010] Preferably, in each variable rotor unit, the rotating shaft is evenly connected to 4 to 8 lower sliding rods in the circumferential direction under the annular magnet.

[0011] Preferably, the angle between the axis of the lower slide bar and the axis of the rotating shaft is 45° to 60°.

[0012] Preferably, there is a clearance fit between the upper slide bar and the upward sliding block, there is a clearance fit between the lower slide bar and the downward sliding block, and the shape of the fixed rotor unit is cylindrical.

[0013] The present invention further provides a flywheel energy storage system, wherein the flywheel rotor of the flywheel energy storage system adopts the flywheel rotor with variable rotational inertia as described above in the present invention.

[0014] Preferably, the above-mentioned flywheel energy storage system of the present invention also includes a shell and an electric motor, the flywheel rotor with variable rotational inertia is arranged in the shell, the rotating shaft is arranged vertically, the lower end of the rotating shaft is rotatably connected to the bottom of the shell, the upper end of the rotating shaft passes through the upper end of the shell, the upper end of the rotating shaft is rotatably and sealedly connected to the shell, and the output shaft of the motor is connected to the upper end of the rotating shaft.

[0015] The present invention has the following beneficial effects: In the flywheel rotor with variable moment of inertia of the present invention, an upper slide bar and a lower slide bar are provided, an upper slider is sleeved on the upper slide bar, and a lower slider is sleeved on the lower slide bar, and an annular magnet can attract the upper slider and the lower slider by magnetic force. Therefore, during the rotation process of the flywheel rotor with variable moment of inertia of the present invention, at the beginning, the upper slider and the lower slider are both attracted by the annular magnet. As the speed of the flywheel rotor with variable moment of inertia of the present invention increases, due to the combined effect of centripetal force and gravity, the lower slider will first slide downward along the lower slide bar and gradually move away from the rotating shaft. When the lower slider slides along the lower slide bar, the entire The mass distribution of the flywheel rotor with variable moment of inertia changes, and the moment of inertia becomes larger, thereby improving the energy storage capacity of the flywheel rotor with variable moment of inertia of the present invention; after the lower slider slides along the lower slide bar to the second limit structure, as the rotation speed increases, due to the combined effect of centripetal force and gravity, the upper slider slides along the upper slide bar and gradually moves away from the rotating shaft. When the upper slider slides along the upper slide bar, the mass distribution of the entire flywheel rotor with variable moment of inertia changes, and the moment of inertia becomes larger, thereby further improving the energy storage capacity of the flywheel rotor with variable moment of inertia of the present invention. The present invention changes the moment of inertia of the flywheel rotor with variable moment of inertia, so that the output and input power of the flywheel energy storage body are flexible and changeable during the charging and discharging process, and can instantly increase the charging amount or instantly reduce the discharging amount. The adjustment is flexible and can well match the primary frequency modulation and secondary frequency modulation instructions of the power grid. In addition, the rotating shaft of the present invention is evenly connected to a plurality of upwardly inclined upper slide bars on the upper circumference of the annular magnet, and the rotating shaft is evenly connected to a plurality of downwardly inclined lower slide bars on the lower circumference of the annular magnet, so that the axial force on the rotating shaft can be reduced as much as possible, ensuring the stability of the rotating shaft position. In addition, since the upper slide bars and the lower slide bars in the variable rotor unit are both inclined, there will be a certain space between adjacent variable rotor units and between adjacent upper slide bars and lower slide bars. In order to improve the overall energy storage capacity of the flywheel rotor with variable moment of inertia of the present invention, the variable rotor unit and the fixed rotor unit are arranged alternately, so that the fixed rotor unit can make full use of the space between adjacent variable rotor units. Compared with the form of arranging the variable rotor unit on one side of the rotating shaft and the fixed rotor unit on the other side of the rotating shaft, the flywheel rotor with variable moment of inertia of the present invention has better stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a flywheel energy storage device with variable moment of inertia of the present invention; Figure 2 It is a schematic diagram of the rotor structure in the flywheel energy storage device with variable rotational inertia of the present invention.

[0017] Among them: 1 is the housing; 2 is the flywheel rotor; 201 is the rotating shaft; 202 is the annular magnet; 203 is the lower slide bar; 204 is the lower slider; 205 is the upper slide bar; 206 is the upper slider; 207 is the fixed rotor; 3 is the motor. DETAILED DESCRIPTION

[0018] The present invention is described clearly and completely below in conjunction with the accompanying drawings and embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, not all embodiments.

[0019] See also Figure 1 and Figure 2 The flywheel rotor with variable moment of inertia in this embodiment includes a rotating shaft 201, on which a variable rotor unit with variable moment of inertia and a fixed rotor unit with fixed moment of inertia are arranged alternately; specifically, the variable rotor unit includes an annular magnet 202 fixedly sleeved on the rotating shaft 201, and the rotating shaft 201 is circumferentially evenly connected with a plurality of upwardly inclined upper slide bars 205 on the upper side of the annular magnet 202, and each upper slide bar 205 is sleeved with an upward sliding block 205 that can slide along the upper slide bar 205 06, the upper slide bar 205 is provided with a first limiting structure (not shown in the figure) for upper positioning of the upper slider 206; the rotating shaft 201 is evenly connected to a plurality of downwardly inclined lower slide bars 203 on the lower side of the annular magnet 202 in the circumferential direction, each of the lower slide bars 203 is sleeved with a lower slider 204 that can slide along the lower slide bar 203, and the lower slide bar 203 is provided with a second limiting structure (not shown in the figure) for lower positioning of the lower slider 204; the annular magnet 202 can attract the upper slider 206 and the lower slider 204 by magnetic force.

[0020] The working principle of the flywheel rotor with variable moment of inertia in the above embodiment of the present invention is as follows: When the shaft 201 is driven to rotate, at the beginning, the rotation speed of the shaft 201 is low. At this time, the upper slider 206 and the lower slider 204 are both attracted by the annular magnet 202, that is, at this time, the upper slider 206 and the lower slider 204 are both in a position close to the annular magnet 202. As the rotation speed of the shaft 201 increases, due to the combined effect of centripetal force and gravity, the lower slider 204 will first slide downward along the lower slide bar 203 and gradually move away from the shaft 201. When the lower slider 204 slides along the lower slide bar 203, the distance between the lower slider 204 and the shaft 201 increases, thereby changing the mass distribution of the entire flywheel rotor with a variable moment of inertia, and causing the entire shaft 201 to rotate. The moment of inertia of the flywheel rotor with variable kinetic inertia increases, thereby improving the energy storage capacity of the flywheel rotor with variable moment of inertia; after the downward slider 204 slides along the lower slide bar 203 to the second limiting structure, as the rotation speed of the rotating shaft 201 increases, due to the combined effects of centripetal force and gravity, the upward slider 206 slides along the upper slide bar 205 and gradually moves away from the rotating shaft 201. When the upward slider 206 slides along the upper slide bar 205, the mass distribution of the entire flywheel rotor with variable moment of inertia changes again, and further increases the moment of inertia of the entire flywheel rotor with variable moment of inertia, thereby further improving the energy storage capacity of the flywheel rotor with variable moment of inertia of the present invention.

[0021] It should be noted that in the above embodiment of the present invention, during the acceleration of the rotation of the rotating shaft 201, the downward slider 204 first slides along the downward slide bar 203. After the downward slider 204 moves to the end of the downward slide bar 203 and is limited by the second limiting structure, the upward slider 206 slides along the upper slide bar 205. The realization of the above process is related to the mass of the downward slider 204, the mass of the upper slider 206, the inclination angle of the downward slide bar 203 and the inclination angle of the upper slide bar 205. Those skilled in the art can flexibly adjust the parameters (i.e., the mass of the downward slider 204, the mass of the upper slider 206, the inclination angle of the downward slide bar 203 and the inclination angle of the upper slide bar 205) according to actual conditions to realize the above process, and the present invention does not make specific limitations.

[0022] As a feasible solution of the present invention, in this embodiment, the lower end of the upper slide bar 205 is fixedly connected to the rotating shaft 201, and the upper end of the upper slide bar 205 passes through the annular magnet 202. In each variable rotor unit, the rotating shaft 201 is evenly connected to 4 to 8 upper slide bars 205 on the upper side of the annular magnet 202. The angle between the axis of the upper slide bar 205 and the axis of the rotating shaft 201 is 45° to 60°. The upper end of the lower slide bar 203 is fixedly connected to the rotating shaft 201, and the lower end of the lower slide bar 203 passes through the annular magnet 202. In each variable rotor unit, the rotating shaft 201 is evenly connected to 4 to 8 lower slide bars 203 on the lower side of the annular magnet 202. The angle between the axis of the lower slide bar 203 and the axis of the rotating shaft 201 is 45° to 60°.

[0023] As a preferred embodiment of the present invention, in this embodiment, there is a clearance fit between the upper slide bar 205 and the upper slider 206, and there is a clearance fit between the lower slide bar 203 and the lower slider 204. This can ensure that the resistance of the upper slider 206 when sliding on the upper slide bar 205 and the lower slider 204 when sliding on the lower slide bar 203 is small and the sliding is flexible. On the other hand, it can also reduce the vibration generated when the upper slider 206 slides on the upper slide bar 205 and the lower slider 204 slides on the lower slide bar 203, thereby ensuring the stability of the entire flywheel rotor with variable moment of inertia during rotation. In addition, the shape of the fixed rotor unit of the present invention can be cylindrical, which can increase the inertia of the entire flywheel rotor with variable moment of inertia and improve the energy storage capacity.

[0024] The flywheel energy storage system of this embodiment is as follows Figure 1 As shown, the flywheel rotor 2 of the flywheel energy storage system adopts the flywheel rotor with variable moment of inertia provided by the above embodiment of the present invention. Specifically, the flywheel energy storage system of the present invention also includes a housing 1 and a motor 3, wherein the flywheel rotor with variable moment of inertia is arranged in the housing 1, the rotating shaft 201 is arranged vertically, the lower end of the rotating shaft 201 is rotatably connected to the bottom of the housing 1, the upper end of the rotating shaft 201 passes through the upper end of the housing 1, the upper end of the rotating shaft 201 is rotatably and sealedly connected to the housing 1, and the output shaft of the motor 3 is connected to the upper end of the rotating shaft 201.

[0025] Example The flywheel energy storage system of this embodiment includes a shell 1, a flywheel rotor 2 and a motor 3, wherein the flywheel rotor 2 adopts the above-mentioned flywheel rotor with variable moment of inertia. Specifically, the flywheel rotor 2 includes a rotating shaft 201, on which are provided three variable rotor units with variable moment of inertia and two fixed rotor units with fixed moment of inertia, and the three variable rotor units and the two fixed rotor units are arranged alternately; specifically, the fixed rotor unit is cylindrical in shape, which is recorded as a fixed rotor 207; each variable rotor unit includes an annular magnet 202 fixedly sleeved on the rotating shaft 201, and the rotating shaft 201 is circumferentially evenly connected with six upwardly inclined upper slide bars 205 on the upper side of the annular magnet 202, the lower end of the upper slide bar 205 is fixedly connected to the rotating shaft 201, the upper end of the upper slide bar 205 passes through the annular magnet 202, and the axis of the upper slide bar 205 is aligned with the rotating shaft 2 The axis angle of 01 is 60°, and each upper slide bar 205 is provided with an upper sliding block 206 that can slide along the upper slide bar 205, and there is a clearance fit between the upper slide bar 205 and the upper sliding block 206, and a first limit stop block is provided on the upper sliding block 205 to upper limit the upper sliding block 206; the rotating shaft 201 is evenly connected with six downwardly inclined lower slide bars 203 on the lower side of the annular magnet 202 in the circumferential direction, and the upper end of the lower slide bar 203 is fixedly connected to the rotating shaft 201, and the lower end of the lower slide bar 203 passes through the annular magnet 202, and the axis of the lower slide bar 203 is at an angle of 60° with the axis of the rotating shaft 201, and each lower slide bar 203 is provided with a lower sliding block 204 that can slide along the lower slide bar 203, and there is a clearance fit between the lower slide bar 203 and the lower sliding block 204, and a second limit stop block is provided on the lower slide bar 203 to lower limit the lower sliding block 204. The flywheel rotor 2 is arranged in the shell 1, and the rotating shaft 201 is arranged vertically. The lower end of the rotating shaft 201 is rotatably connected to the bottom of the shell 1, and the upper end of the rotating shaft 201 passes through the upper end of the shell 1. The upper end of the rotating shaft 201 is rotatably and sealedly connected to the shell 1, and the output shaft of the motor 3 is connected to the upper end of the rotating shaft 201.

[0026] The operation mode of the flywheel energy storage system in this embodiment is as follows: When the power demand on the user side decreases, the grid frequency will be greater than 50Hz instantly. At this time, the power supply side needs to reduce the load in time to reduce the grid frequency and ensure grid stability. In this scenario, the flywheel rotor 2 of the flywheel energy storage system of this embodiment needs to make full use of the power output of the thermal power generator to store energy and increase the speed of the flywheel rotor 2. At the same time, the power output of the generator is reduced, thereby timely reducing the power delivered to the grid. When the flywheel energy storage system is continuously charged and the speed of the flywheel rotor 2 is continuously increased, when the speed of the flywheel rotor 2 (which is also the speed of the rotating shaft 201) is less than 1000r / min, ignoring the influence of friction, the combined force of the centripetal force, gravity and the supporting force of the slide bars (i.e., the upper slide bar 205 and the lower slide bar 203) on the movable sliders (i.e., the upper slide bar 206 and the lower slide bar 204) is less than the attraction of the annular magnet 202 to the sliders (i.e., the upper slide bar 206 and the lower slide bar 204), and the movable sliders (i.e., the upper slide bar 206 and the lower slide bar 204) are fixed to the rotating shaft 201 by the annular magnet 202 and rotate.

[0027] When the rotation speed of the flywheel rotor 2 is greater than or equal to 1000r / min, ignoring the influence of friction, the combined force of the centripetal force, gravity and the supporting force of the lower slide bar 203 on the lower slide bar 204 is greater than the attraction of the annular magnet 202 on the lower slide bar 204. At this time, the lower slide bar 204 can slide along the lower slide bar 203, storing energy as the flywheel rotor 2 rotates, and the sliding position of the lower slide bar 204 is finally limited by the second limit block at the lower end of the lower slide bar 203.

[0028] When the speed of the flywheel rotor 2 is greater than or equal to 1200r / min, ignoring the influence of friction, the combined force of the centripetal force, gravity and the supporting force of the upper slide bar 205 on the upper slide bar 206 on the upper slide bar 206 is greater than the attraction of the annular magnet 202 on the upper slide bar 206. At this time, the upper slide bar 206 slides upward along the upper slide bar 205, and stores energy as the flywheel rotor 2 rotates. The sliding position of the upper slide bar 206 is finally limited by the first limit block at the upper end of the upper slide bar 205. At this time, the lower slide bar 204 and the upper slide bar 206 are both at the edge of the corresponding slide bar (i.e., the lower slide bar 203 and the upper slide bar 205), and the rotation energy is stored.

[0029] When the amount of electricity demanded by the user side increases, the grid frequency will be less than 50Hz instantaneously. At this time, the power supply side needs to increase the load in time to increase the grid frequency and ensure grid stability. In this scenario, the flywheel rotor 2 of the flywheel energy storage system of this embodiment needs to make full use of its own rapid response characteristics to quickly release the stored electricity to increase the instantaneous amount of electricity in the grid and ensure the stability of the grid frequency. During the discharge process, the speed of the flywheel rotor 2 decreases. When the flywheel energy storage system is continuously discharged and the speed of the flywheel rotor 2 is continuously reduced, when the speed of the flywheel rotor 2 is reduced from the rated 3000r / min to 1200r / min, the downward slider 204 is still at the lower end of the lower slide bar 203, and the upward slider 206 is still at the upper end of the upper slide bar 205.

[0030] When the rotation speed of the flywheel rotor 2 decreases from 1200r / min to 1000r / min, ignoring the influence of friction, the combined force of the centripetal force, gravity and the supporting force of the upper slide bar 205 on the upper slide bar 206 is smaller than the attraction of the annular magnet 202 on the upper slide bar 206. The upper slide bar 206 will gradually slide back to the annular magnet 202 along the upper slide bar 205 and be attracted by the annular magnet 202.

[0031] When the speed of the flywheel rotor 2 is reduced to 1000r / min, ignoring the influence of friction, the combined force of the centripetal force, gravity and the supporting force of the lower slide bar 203 on the lower slide bar 204 is smaller than the attraction of the annular magnet 202 on the lower slide bar 204, and the lower slide bar 204 will gradually slide back to the annular magnet 202 along the lower slide bar 203 and be attracted by the annular magnet 202. At this point, the upper slide bar 206 and the lower slide bar 204 are both fixed to the rotating shaft 201 by the annular magnet 202 and rotate.

[0032] The primary frequency modulation command of the power grid is small and fluctuates quickly. The amount of electricity required for each frequency modulation is very small, but the required time is short. The general frequency modulation time is 20s, that is, the excess electricity needs to be consumed or supplemented within 20s. When the present invention is at a low speed, at this time, the upper slider 206 and the lower slider 204 are both fixed to the rotating shaft 201 by the annular magnet 202, so that it can well match the primary frequency modulation of the power grid (at a low speed, the charge and discharge amount is small, and the response time is the same as that at a high speed).

[0033] The grid secondary frequency modulation (AGC) instruction presents a large instruction, and there is a high probability of continuous same direction or reverse direction. The general frequency modulation time is 3 to 6 minutes, and the charge and discharge amount at low speed cannot meet its requirements. When the grid positive secondary frequency modulation instruction (charging instruction) is given to the flywheel energy storage system, the flywheel energy storage system needs to quickly absorb and store the electricity in the flywheel rotor 2. Specifically, the greater the moment of inertia of the flywheel rotor 2 and the higher the speed, the greater the stored electricity; so the slider (i.e., the upper slider 206 and the lower slider 204) of the present invention is as the electricity is continuously converted into the speed of the flywheel rotor 2, the lower slider 204 slowly moves down to the outside (i.e., the lower end of the lower slide bar 203), and the amount of electricity stored per second in this process is also continuously increased, which improves the rate of electricity storage. When the lower slider 204 slides to the lower end of the lower slide bar 203, the upper slider 206 also slowly moves up to the outside (i.e., the upper end of the upper slide bar 205), and the amount of electricity stored per second in this process is also continuously increased, which also improves the rate of electricity storage.

[0034] When the grid reverse secondary frequency modulation instruction (discharge instruction) is given to the flywheel energy storage system, the flywheel energy storage system needs to quickly discharge to the grid. As the speed of the flywheel rotor 2 decreases, the upper slider 206 and the lower slider 204 are successively fixed to the shaft 201 by the annular magnet 202 and rotate. At the same time, the rotational inertia of the flywheel rotor 2 gradually decreases, and the energy is quickly converted into electricity and released, thereby realizing rapid replenishment of electricity.

[0035] It can be seen from the above scheme that the flywheel rotor and flywheel energy storage system with variable moment of inertia proposed by the present invention, by adopting the structural change of the flywheel rotor 2, can change the moment of inertia of the flywheel rotor 2 as the speed changes during the charging and discharging process, bringing about the change of the moment of inertia of the entire rotor system, thereby realizing energy storage and energy release. The present invention changes the moment of inertia of the flywheel rotor 2, so that the output and input power of the flywheel energy storage system are flexible and changeable during the charging and discharging process, and can instantly increase the charge amount or instantly reduce the discharge amount. The adjustment is flexible and can well match the primary and secondary frequency modulation instructions of the power grid. At the same time, the present invention has a simple structure, can reduce investment costs, and has higher returns.

[0036] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A flywheel rotor with variable moment of inertia, characterized in that: It comprises a rotating shaft (201), on which a variable rotor unit with a variable moment of inertia and a fixed rotor unit with a fixed moment of inertia are arranged, the variable rotor unit and the fixed rotor unit being arranged alternately; The variable rotor unit comprises an annular magnet (202) fixedly sleeved on a rotating shaft (201); the rotating shaft (201) is evenly connected to a plurality of upwardly inclined upper slide bars (205) on the upper side of the annular magnet (202) in the circumferential direction; each upper slide bar (205) is sleeved with an upward sliding block (206) capable of sliding along the upper sliding block (205); the upper sliding block (205) is provided with a first limiting structure for performing an upper limit position on the upward sliding block (206); the rotating shaft (201) is evenly connected to a plurality of downwardly inclined lower slide bars (203) on the lower side of the annular magnet (202) in the circumferential direction; each lower sliding block (203) is sleeved with a downward sliding block (204) capable of sliding along the lower sliding block (203); the lower sliding block (203) is provided with a second limiting structure for performing a lower limit position on the downward sliding block (204); the annular magnet (202) is capable of attracting the upward sliding block (206) and the downward sliding block (204) by magnetic force.

2. A flywheel rotor with variable moment of inertia according to claim 1, characterized in that: The lower end of the upper slide bar (205) is fixedly connected to the rotating shaft (201), and the upper end of the upper slide bar (205) passes through the annular magnet (202).

3. A flywheel rotor with variable moment of inertia according to claim 1, characterized in that: In each variable rotor unit, the rotating shaft (201) is evenly connected to 4 to 8 upper sliding bars (205) in the circumferential direction on the upper side of the annular magnet (202).

4. A flywheel rotor with variable moment of inertia according to claim 1, characterized in that: The included angle between the axis of the upper slide bar (205) and the axis of the rotating shaft (201) is 45° to 60°.

5. A flywheel rotor with variable moment of inertia according to claim 1, characterized in that: The upper end of the lower sliding rod (203) is fixedly connected to the rotating shaft (201), and the lower end of the lower sliding rod (203) passes through the annular magnet (202).

6. A flywheel rotor with variable moment of inertia according to claim 1, characterized in that: In each variable rotor unit, the rotating shaft (201) is evenly connected to 4 to 8 lower sliding rods (203) in the circumferential direction below the annular magnet (202).

7. A flywheel rotor with variable moment of inertia according to claim 1, characterized in that: The included angle between the axis of the lower slide bar (203) and the axis of the rotating shaft (201) is 45° to 60°.

8. A flywheel rotor with variable moment of inertia according to claim 1, characterized in that: There is a clearance fit between the upper slide bar (205) and the upper sliding block (206), there is a clearance fit between the lower slide bar (203) and the lower sliding block (204), and the shape of the fixed rotor unit is cylindrical.

9. A flywheel energy storage system, characterized in that: The flywheel rotor (2) of the flywheel energy storage system adopts the flywheel rotor with variable rotational inertia as claimed in any one of claims 1 to 8.

10. A flywheel energy storage system according to claim 9, characterized in that: It also comprises a housing (1) and an electric motor (3), wherein the flywheel rotor with a variable moment of inertia is arranged in the housing (1), the rotating shaft (201) is arranged vertically, the lower end of the rotating shaft (201) is rotatably connected to the bottom of the housing (1), the upper end of the rotating shaft (201) passes through the upper end of the housing (1), the upper end of the rotating shaft (201) is rotatably and hermetically connected to the housing (1), and the output shaft of the electric motor (3) is connected to the upper end of the rotating shaft (201).

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