Flywheel energy storage permanent magnet synchronous motor stator and rotor end assembly and flywheel energy storage system

Abstract

The application provides a flywheel energy storage permanent magnet synchronous motor stator-rotor end assembly and a flywheel energy storage system, the end assembly comprising a stator end, a rotor end and a conical air gap; the stator end comprises a first conical surface; the rotor end comprises a second conical surface; the first conical surface and the second conical surface form a conical air gap at the stator-rotor concentric position, wherein the conical air gap is designed with an expanding angle from the center to the outside, for generating a radial induction lifting electromagnetic force through the electromagnetic induction principle. The application generates a radial lifting force through the electromagnetic induction by the design of the stator-rotor end conical air gap, shares the bearing load to reduce the friction loss, and at the same time enhances the rotor rigidity to suppress resonance, thereby improving the efficiency and reliability of the flywheel energy storage motor.

Description

Technical Field

[0001] This application belongs to the field of mechanical energy storage, and in particular relates to a flywheel energy storage permanent magnet synchronous motor stator and rotor end assembly and a flywheel energy storage system. Background Technology

[0002] In the field of flywheel energy storage technology, such as Figure 4 The permanent magnet synchronous motor shown is widely used for storing and releasing electrical energy due to its high efficiency, high power density and good speed regulation performance.

[0003] However, in high-speed, high-energy flywheel energy storage systems, frictional losses between the stator and rotor of the motor become one of the key factors restricting system efficiency and lifespan. Traditional permanent magnet synchronous motor designs often employ parallel air gaps. This structure easily leads to increased bearing loads and frictional losses at high speeds, thus affecting the overall performance and lifespan of the motor. To reduce frictional losses and improve system efficiency, some designs have attempted to use independent electromagnetic non-contact bearings. However, these solutions often suffer from large size and low space utilization, making it difficult to meet the dual requirements of compactness and high efficiency for flywheel energy storage systems. Summary of the Invention

[0004] The purpose of this application is to overcome the defects in the prior art and provide a flywheel energy storage permanent magnet synchronous motor stator and rotor end assembly and a flywheel energy storage system.

[0005] This application provides a stator and rotor end assembly for a flywheel energy storage permanent magnet synchronous motor, including a stator end, a rotor end, and a tapered air gap;

[0006] The stator end includes a first tapered surface;

[0007] The rotor end includes a second conical surface;

[0008] The first conical surface and the second conical surface form a conical air gap at the concentric position of the stator and rotor. The conical air gap is designed to expand outward from the center to generate a radially induced lifting electromagnetic force through the principle of electromagnetic induction.

[0009] Optionally, the conical air gap is designed with an expanding angle from the center outwards, including:

[0010] The expansion angle is smaller in the upper region than in the lower region when the stator and rotor are concentric.

[0011] Optionally, the stator end includes a first tapered surface, comprising:

[0012] The inner side of the first conical surface facing the rotor end is a concave curved surface.

[0013] Optionally, the rotor end includes a second tapered surface, comprising:

[0014] The second conical surface is a convex curved surface facing the stator end, and the radius of curvature decreases along the axial direction.

[0015] Optionally, in the design where the conical air gap expands outward from the center, the expansion direction of the conical air gap includes:

[0016] The extension direction forms a fixed angle with the vertical axis, and the direction of the angle is toward the concentric center of the stator and rotor.

[0017] Optionally, the stator end includes:

[0018] The stator end core has an oblique through slot, and the extension direction of the oblique through slot is parallel to the winding direction.

[0019] Optionally, the stator end includes a winding, comprising:

[0020] The winding is wound with a single-sided bevel in the end region, and the bevel direction is away from the rotor rotation center.

[0021] This application also provides a flywheel energy storage system, including a vacuum chamber, a bearing system, an energy storage flywheel, and a permanent magnet synchronous motor;

[0022] The permanent magnet synchronous motor includes a stator assembly, a rotor assembly, and the aforementioned flywheel energy storage permanent magnet synchronous motor stator and rotor end assemblies.

[0023] The rotor assembly is coaxially connected to the energy storage flywheel;

[0024] The permanent magnet synchronous motor is arranged vertically inside the vacuum chamber;

[0025] The bearing system supports the axial loads of the rotor assembly and the energy storage flywheel;

[0026] The tapered air gap in the stator and rotor end assembly generates a radially induced lifting electromagnetic force to share the load of the bearing system.

[0027] Optionally, the vacuum chamber includes:

[0028] The inner wall of the vacuum chamber integrates spirally extending cooling channels, the inlet of which is connected to an external cooling medium source, and the outlet faces the bearing system.

[0029] The spiral direction of the spirally extended cooling channel is opposite to the direction of rotor rotation.

[0030] Optionally, the rotor assembly is coaxially connected to the energy storage flywheel, including:

[0031] The output shaft end of the rotor assembly is provided with a bidirectional tapered keyway;

[0032] The inner wall of the hub of the energy storage flywheel is provided with a bidirectional tapered key;

[0033] The bidirectional tapered key and the bidirectional tapered keyway are interference-fitted, and the taper direction is away from the rotation center.

[0034] The beneficial effects of this application are:

[0035] This application provides a stator and rotor end assembly for a flywheel energy storage permanent magnet synchronous motor, including a stator end, a rotor end, and a conical air gap. The stator end includes a first conical surface; the rotor end includes a second conical surface. The first and second conical surfaces form a conical air gap at a concentric position between the stator and rotor. The conical air gap is designed with an expanding angle from the center outwards to generate a radially induced lifting electromagnetic force through electromagnetic induction. This application utilizes the conical air gap design at the stator and rotor ends to generate a radial lifting force through electromagnetic induction, thereby distributing the bearing load to reduce frictional losses and enhancing rotor rigidity to suppress resonance, thus improving the efficiency and reliability of the flywheel energy storage motor. Attached Figure Description

[0036] Figure 1 This is a schematic front view cross-section of the stator and rotor in this application;

[0037] Figure 2 This is a schematic diagram of the side cross-section of the motor end in this application;

[0038] Figure 3 This is a bottom view schematic diagram of the stator and rotor in this application;

[0039] Figure 4 This is a schematic diagram of the prototype permanent magnet synchronous motor energy storage flywheel in this application. Detailed Implementation

[0040] Exemplary embodiments of the present disclosure will now be provided in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it is to be understood that various forms of implementation of the present disclosure are intended and should not be limited to the embodiments set forth herein. Rather, the embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0041] Please refer to Figure 1 , Figure 2 and Figure 3 As shown, this application provides a stator and rotor end assembly 10 of a flywheel energy storage permanent magnet synchronous motor, which includes a stator end 20, a rotor end 10, and a tapered air gap. This assembly is used to reduce frictional losses, improve space utilization, and increase system efficiency in a flywheel energy storage system. It generates a radially induced lifting electromagnetic force through a special end structure, thereby sharing the bearing load.

[0042] The stator end 20 includes a first conical surface 201; the rotor end 10 includes a second conical surface 101; the first conical surface 201 and the second conical surface 101 form a conical air gap at the concentric position of the stator and rotor.

[0043] Specifically, in the application of flywheel energy storage permanent magnet synchronous motors, the stator end 20 is designed with a first conical surface 201, which is a concave curved surface facing the inner side of the rotor end 10. Preferably, the stator end 20 includes an iron core, which not only supports the oblique through slot but also increases the axial magnetic pull and fixes the winding; in practice, the presence of the iron core can optimize the magnetic field distribution and avoid the problem of reduced magnetic pull. The rotor end 10 is designed with a second conical surface 101, which is a convex curved surface facing the outer side of the stator end 20, and the radius of curvature decreases along the axial direction.

[0044] When the stator and rotor are in a concentric position, a conical air gap is formed between the first conical surface 201 and the second conical surface 101. The design of this conical air gap causes it to expand outwards from the center at a fixed angle, with the direction of expansion forming a fixed angle with the vertical axis, pointing towards the concentric center of the stator and rotor. This structure operates based on the principle of electromagnetic induction, generating a radially induced lifting electromagnetic force during motor operation, thereby reducing the load on the axial bearings.

[0045] The stator end 20 also includes an oblique through slot, the extension direction of which is parallel to the winding direction, which helps to optimize the magnetic field distribution.

[0046] The first conical surface 201 of the stator end 20 is specifically a concave curved surface. This curved surface shape ensures that when the stator and rotor are concentric, the magnetic circuit of the air gap can concentrate the magnetic field and improve the electromagnetic induction efficiency.

[0047] The second conical surface 101 at the rotor end 10 is a convex curved surface with a radius of curvature that decreases axially. From the center of the rotor outward, the curvature gradually decreases, forming a smooth transition to reduce the risk of magnetic circuit saturation.

[0048] When the first and second conical surfaces 101 are aligned concentrically, the resulting conical air gap not only provides mechanical support but also generates a lifting force through electromagnetic induction. For example, during motor operation, after the stator windings are energized, the magnetic field is distributed in the conical air gap. Due to the conical design of the surface, the magnetic lines of force generate a radial component, thereby generating a lifting force.

[0049] The conical air gap is designed to expand outward from the center, which is used to generate radial lifting electromagnetic force through the principle of electromagnetic induction.

[0050] The design of the conical air gap's expansion angle is specifically manifested in the following way: in the upper region where the stator and rotor are concentric, the expansion angle is smaller than that in the lower region. This angular difference ensures that as the air gap expands outward from the center, the upper region is narrower and the lower region is wider, thus optimizing the radial distribution of the magnetic field. The expansion direction forms a fixed angle with the vertical axis, which points towards the center of the concentric circles of the stator and rotor. This helps to generate an asymmetric magnetic field in the air gap, thereby generating a radial lifting electromagnetic force. During the electromagnetic induction process, the stator winding current generates a magnetomotive force, distributed in an ideal sinusoidal form, specifically expressed by the following formula:

[0051]

[0052] in, denoted as the amplitude of the motor winding current, P as the number of motor pole pairs, f as the frequency of the motor winding current, α as the angle of the circumferential position of the air gap in the vertical bottom view, and t as time.

[0053] This magnetomotive force is converted into a magnetic flux density distribution through Ohm's law for magnetic circuits. :

[0054]

[0055] in, This represents the stator winding coefficient.

[0056] Since the adjacent iron cores on both sides of the end stator and rotor are parallel, and without considering the tooth slots, it can be approximated that the magnetic flux passes through the air gap along the normal direction of the inner surface of the iron core. Therefore, the magnetic reluctance of this part of the magnetic circuit... :

[0057]

[0058] in, The permeability of free space, ρ is the relative permeability of air. The effective cross-sectional area of ​​the end-of-air breath. The thickness of the end air gap.

[0059] like Figure 2 As shown, This indicates the thickness of the motor's main air gap. Indicates the axial length of the stator end core. Peak value of the magnetic flux density distribution. Used to calculate radial magnetic pull:

[0060]

[0061] in, To estimate the magnetic flux density and tension coefficient, electromagnetic simulation software can be used to simulate different excitation currents and directly read the radial electromagnetic force. and air gap magnetic flux density peak Through data fitting, we can obtain... The specific value.

[0062] Ultimately, the vertical component of the radial magnetic pull is decomposed into the electromagnetic lifting force of the rotor:

[0063]

[0064] Where θ is the angular parameter of the conical air gap.

[0065] In the specific implementation of the extended angle design, the difference between the smaller angle in the upper region (e.g., 10-15 degrees) and the larger angle in the lower region (e.g., 20-30 degrees) ensures that the magnetic field lines generate a larger component in the vertical direction when the air gap expands. Based on this, the asymmetry of the conical air gap is utilized to improve the utilization rate of the motor current while avoiding the waste of space in independent bearings. For example, when the flywheel energy storage system rotates at high speed, the change in the magnetic field in the conical air gap generates an induced lifting force, as shown by the formula calculation. Directly proportional to the stator current amplitude This reduces frictional loss.

[0066] Friction loss formula:

[0067]

[0068] in, For bearing load, is the bearing load loss coefficient, and f is the current frequency when the motor is running.

[0069] The formula verifies the lifting force. How to reduce bearing load and improve efficiency.

[0070] The stator end 20 includes a winding; the winding is wound with a single-sided bevel in the end region.

[0071] The stator end 20 winding design employs a single-sided oblique winding in the end region, with the oblique direction facing away from the rotor's rotation center. This winding method is implemented in conjunction with the oblique through-slot gaps in the stator core, with the slot extension direction parallel to the winding direction. Specifically, the oblique through-slot gaps ensure that the winding can be arranged obliquely in the end region, thereby optimizing the magnetic field path. The single-sided oblique winding, with the oblique side facing away from the rotor center, avoids magnetic field interference and improves current efficiency. In implementation, the winding is based on the principle of electromagnetic induction and works in conjunction with the tapered air gap design to generate a radial lifting force.

[0072] The single-sided bevel winding at the end region is characterized by the coil forming a bevel angle on one side during winding, away from the rotor's rotation center, ensuring the magnetic field is concentrated in the air gap region. The parallel extension direction through the slot (e.g., aligned with the winding axis) reduces magnetic leakage. For example, during motor assembly, the winding passes through the slot into the end region; the single-sided bevel design optimizes the current path, and combined with the tapered air gap, results in a more uniform electromagnetic force distribution. This improves the rigidity of the end structure, helps increase the rotor's natural frequency, and suppresses the risk of resonance.

[0073] Furthermore, the actual electromagnetic field distribution can be simulated and analyzed using finite element method (FEM) software. The FEM simulation results include the influence of core saturation on saturation, yielding a more accurate radial electromagnetic pull. Moreover, due to the tapered end, the rigidity between the rotor core and the shaft is stronger, effectively increasing the overall natural frequency of the rotor. This natural frequency can be altered by adjusting its shape, reducing the risk of motor resonance. The rotor's natural frequency and vibration noise can also be simulated and analyzed using FEM software (such as Comsol and ANSYS) to measure the strain, natural frequency, and vibration modes of the stator and rotor after load.

[0074] The tapered air gap design is used to generate radially induced lifting electromagnetic force to reduce frictional losses.

[0075] The conical air gap design ultimately generates a radial lifting electromagnetic force through electromagnetic induction, thereby reducing frictional losses in the flywheel energy storage system.

[0076] The friction loss formula is as described above:

[0077]

[0078] The formula shows that the lifting force The increase directly reduces the bearing load. This reduces losses. .

[0079] In practical implementation, the expansion angle of the conical air gap, the surface design of the stator and rotor, and the winding work together to ensure maximum current utilization. For example, in the flywheel energy storage prototype, the end structure integrates a permanent magnet synchronous motor, improving overall efficiency.

[0080] This application also provides a flywheel energy storage system, which includes a vacuum chamber, a bearing system, an energy storage flywheel, and a permanent magnet synchronous motor. This system is designed to reduce frictional losses and improve space utilization and efficiency through a special end structure, specifically by generating a radially induced lifting electromagnetic force through a tapered air gap to distribute the bearing load.

[0081] The system includes a vacuum chamber, a bearing system, an energy storage flywheel, and a permanent magnet synchronous motor.

[0082] In flywheel energy storage applications, the system reduces air friction losses through a vacuum chamber, supports the load through a bearing system, stores kinetic energy through the energy storage flywheel, and converts the energy into energy using a permanent magnet synchronous motor. Specifically, the vacuum chamber houses the system components and reduces air resistance during high-speed rotation; the bearing system supports the axial load of the rotor; the energy storage flywheel, acting as inertial mass, stores and releases kinetic energy; and the permanent magnet synchronous motor achieves efficient energy conversion through electromagnetic interaction. These components work together to improve system efficiency and reliability. For example, in port quay crane applications, flywheel energy storage systems recover kinetic energy during container transfer, reducing braking losses.

[0083] The permanent magnet synchronous motor includes a stator assembly, a rotor assembly, and the aforementioned flywheel energy storage permanent magnet synchronous motor stator and rotor end 10 components.

[0084] The stator end 20 includes a first conical surface 201, which is a concave curved surface facing the inner side of the rotor end 10; the rotor end 10 includes a second conical surface 101, which is a convex curved surface facing the outer side of the stator end 20, and the radius of curvature decreases axially. When the stator and rotor are concentric, the first conical surface 201 and the second conical surface 101 form a conical air gap, which is designed to expand outward from the center, and the expansion direction forms a fixed angle with the vertical axis, the angle direction being towards the concentric center of the stator and rotor. This structure generates a radial lifting electromagnetic force through the principle of electromagnetic induction, thereby reducing the load on the axial bearing. The core of the stator end 20 also includes an oblique through slot, the extension direction being parallel to the winding direction; the winding adopts a single-sided oblique edge winding in the end region, the oblique edge direction being away from the rotor rotation center.

[0085] The first conical surface 201 of the stator end 20 is specifically a concave curved surface, which ensures magnetic circuit concentration at the concentric position and improves electromagnetic efficiency. The curvature of the second conical surface 101 of the rotor end 10 decreases, reducing the risk of magnetic saturation. The extension angle of the conical air gap is designed to be smaller in the upper region than in the lower region at the concentric position, optimizing the magnetic field distribution. In implementation, for example, during motor operation, the stator winding current generates a magnetomotive force:

[0086]

[0087] in, denoted as the amplitude of the motor winding current, P as the number of motor pole pairs, f as the frequency of the motor winding current, α as the angle of the circumferential position of the air gap in the vertical bottom view, and t as time.

[0088] This magnetomotive force is converted into a magnetic flux density distribution through Ohm's law for magnetic circuits:

[0089]

[0090] in, This represents the stator winding coefficient.

[0091] Peak value of magnetic flux density distribution Used to calculate radial magnetic pull:

[0092]

[0093] in, This is the coefficient for estimating magnetic flux density.

[0094] Ultimately, the vertical component of the radial magnetic pull is decomposed into the electromagnetic lifting force of the rotor:

[0095]

[0096] Where θ is the angular parameter of the conical air gap.

[0097] The end design improves space utilization, avoids the volume occupied by independent bearings, and enhances rotor rigidity.

[0098] The rotor assembly is coaxially connected to the energy storage flywheel.

[0099] The rotor assembly is coaxially connected to the energy storage flywheel to ensure efficient energy transfer. In the flywheel energy storage system, the rotor assembly's output shaft is directly connected to the flywheel hub, achieving coaxial rotation. This connection allows the permanent magnet synchronous motor to directly drive the flywheel, optimizing energy conversion efficiency. For example, at high speeds, the coaxial design reduces vibration and energy loss, improving system stability. Logically, this ensures that the inertial flywheel operates synchronously with the motor rotor, achieving effective storage and release of kinetic energy.

[0100] The output shaft end of the rotor assembly is provided with a bidirectional tapered keyway; the inner wall of the energy storage flywheel hub is provided with a bidirectional tapered key; the bidirectional tapered key and the bidirectional tapered keyway are interference-fitted, and the tapered direction is away from the rotation center. This design ensures connection strength through interference fit, and the tapered direction away from the center reduces rotational stress and improves system reliability.

[0101] Permanent magnet synchronous motors are vertically arranged within the vacuum chamber to optimize bearing load distribution and reduce frictional losses. Flywheel energy storage has become a hot topic in high-power-density energy storage due to its advantages such as low cost, ease of placement, and long cycle life. Flywheel energy storage can be further divided into horizontal and vertical types based on its arrangement (direction), i.e., whether the axes of the motor rotor and the inertial flywheel are parallel or perpendicular to the ground. The weight load of the inertial frame in flywheel energy storage requires bearing support to maintain the concentric relative position of the stator and rotor. Because vertical placement results in a more uniform bearing load distribution, most systems adopt a vertical placement scheme. In practical implementation, vertical arrangement ensures uniform bearing load and reduces the load in the frictional loss formula:

[0102]

[0103] in, For bearing load, This is the bearing load loss coefficient.

[0104] The formula shows that the lifting force ,reduce This reduces losses.

[0105] Furthermore, the inner wall of the vacuum chamber integrates spirally extending cooling channels. The inlet of these channels connects to an external cooling medium source, while the outlet faces the bearing system. The spiral direction of the cooling channels is opposite to the rotor's rotation direction. This design optimizes cooling efficiency and reduces bearing temperature rise through the reverse spiral flow.

[0106] The bearing system supports the axial loads of the rotor assembly and energy storage flywheel, ensuring stable system operation. Specifically, the bearing system bears the weight and dynamic loads of the rotor and flywheel, distributing part of the load through end-lift forces. In implementation, the friction loss formula is as described above, the lift force FR is based on this, and the reduction GL is based on this, thereby reducing losses. This extends bearing life and improves overall reliability. For example, in the flywheel energy storage prototype, the bearing system is designed to bear the remaining load, ensuring safe high-speed rotation.

[0107] The tapered air gap in the stator and rotor end assemblies generates a radially induced lifting electromagnetic force to share the load of the bearing system.

[0108] The tapered air gap in the stator and rotor end assemblies generates a radially induced lifting electromagnetic force, directly sharing the load of the bearing system. This lifting force is achieved through the principle of electromagnetic induction, and the calculation formula is as follows:

[0109]

[0110] During system operation, the lifting force reduces bearing load and lowers frictional losses. The tapered air gap design efficiently generates the lifting force without requiring additional space, improving system integration. For example, in a vertical arrangement, the lifting force acts in the opposite direction to gravity, significantly reducing bearing load.

[0111] The above embodiments are provided to enable those skilled in the art to understand and apply this application. Those skilled in the art will readily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without inventive effort. Therefore, this application is not limited to the above embodiments, and any improvements and modifications made to this application based on the disclosure thereof should be within the scope of protection of this application.

Claims

1. A stator and rotor end assembly for a flywheel energy storage permanent magnet synchronous motor, characterized in that, This includes the stator ends, rotor ends, and the tapered air gap; The stator end includes a first tapered surface; The rotor end includes a second conical surface; The first conical surface and the second conical surface form a conical air gap at the concentric position of the stator and rotor. The conical air gap is designed to expand outward from the center to generate a radially induced lifting electromagnetic force through the principle of electromagnetic induction. The expansion angle of the conical air gap is smaller in the upper region than in the lower region when the stator and rotor are concentric. The stator end includes an iron core and a winding. The iron core includes an oblique through slot. The winding is wound on one side with an oblique edge in the end region, and the oblique edge direction is away from the rotor rotation center. The extension direction of the oblique through slot is parallel to the winding direction of the winding. Through the unilateral oblique winding of the winding, the oblique through slot, and the conical air gap working together, the electromagnetic force distribution is made more uniform.

2. The flywheel energy storage permanent magnet synchronous motor stator and rotor end assembly according to claim 1, characterized in that, The stator end includes a first tapered surface, comprising: The inner side of the first conical surface facing the rotor end is a concave curved surface.

3. The flywheel energy storage permanent magnet synchronous motor stator and rotor end assembly according to claim 1, characterized in that, The rotor end includes a second tapered surface, comprising: The second conical surface is a convex curved surface facing the stator end, and the radius of curvature decreases along the axial direction.

4. The flywheel energy storage permanent magnet synchronous motor stator and rotor end assembly according to claim 1, characterized in that, In the design of the conical air gap expanding outward from the center, the expansion direction of the conical air gap includes: The extension direction forms a fixed angle with the vertical axis, and the direction of the angle is toward the concentric center of the stator and rotor.

5. A flywheel energy storage system, characterized in that, Includes vacuum chamber, bearing system, energy storage flywheel, and permanent magnet synchronous motor; The permanent magnet synchronous motor includes a stator assembly, a rotor assembly, and the stator and rotor end assemblies of the flywheel energy storage permanent magnet synchronous motor according to any one of claims 1 to 4; The rotor assembly is coaxially connected to the energy storage flywheel; The permanent magnet synchronous motor is arranged vertically inside the vacuum chamber; The bearing system supports the axial loads of the rotor assembly and the energy storage flywheel; The conical air gap in the stator and rotor end assembly generates a radially induced lifting electromagnetic force to share the load of the bearing system. The expansion angle of the conical air gap is smaller in the upper region than in the lower region when the stator and rotor are concentric. The stator end includes an iron core and a winding. The iron core includes an oblique through slot. The winding is wound on one side with an oblique edge in the end region, and the oblique edge direction is away from the rotor rotation center. The extension direction of the oblique through slot is parallel to the winding direction of the winding. Through the unilateral oblique winding of the winding, the oblique through slot, and the conical air gap working together, the electromagnetic force distribution is made more uniform.

6. The flywheel energy storage system according to claim 5, characterized in that, The vacuum cavity includes: The inner wall of the vacuum chamber integrates spirally extending cooling channels, the inlet of which is connected to an external cooling medium source, and the outlet is directed toward the bearing system. The spiral direction of the spirally extended cooling channel is opposite to the direction of rotor rotation.

7. The flywheel energy storage system according to claim 5, characterized in that, The rotor assembly is coaxially connected to the energy storage flywheel, including: The output shaft end of the rotor assembly is provided with a bidirectional tapered keyway; The inner wall of the hub of the energy storage flywheel is provided with a bidirectional tapered key; The bidirectional tapered key and the bidirectional tapered keyway are interference-fitted, and the taper direction is away from the rotation center.

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