Multi-stage vibration isolation structure of flywheel energy storage system

Abstract

A multistage vibration reduction and isolation structure of a flywheel energy storage system is used for reducing the vibration of a flywheel energy storage body, which comprises a flywheel shaft system and a body shell, the flywheel shaft system being located in the body shell, the multistage vibration reduction and isolation structure comprising a connecting plate, a viscoelastic material and a pre-embedded cover plate, the flywheel energy storage body being fixedly installed on the connecting plate through a plurality of high-strength bolts, the pre-embedded cover plate being fixed on a concrete base, the connecting plate being located above the pre-embedded cover plate, and the connecting plate and the pre-embedded cover plate jointly forming a clearance in meshing with each other, the clearance accommodating the viscoelastic layer. The non-fixed interface cooperation between the connecting plate and the pre-embedded cover plate makes the system trigger the shear, sliding and inclined plane compression and shear mechanisms in turn under different amplitudes, thereby ensuring the safety of the magnetic suspension bearing control system in the flywheel shaft system.

Description

Technical Field

[0001] This invention relates to the field of energy storage flywheel technology, and more specifically to a multi-stage vibration reduction and isolation structure for a flywheel energy storage system. Background Technology

[0002] Flywheel energy storage is a physical energy storage technology. Its principle is to utilize the conversion between the electrical energy of an electric generator that rotates coaxially with the flywheel and the kinetic energy of the rotating flywheel: In the energy storage stage, the electric motor drives the flywheel to accelerate it, converting electrical energy into rotational kinetic energy for storage; in the energy release stage, the electric motor operates as a generator, causing the flywheel to decelerate, converting kinetic energy into electrical energy for output.

[0003] Flywheel energy storage systems, as high-speed, long-life physical energy storage devices, are centered around a high-speed rotating flywheel shaft system. Due to the uniqueness of its physical mechanism, the applicability of a site can be effectively improved by using external vibration damping and isolation structures. Flywheel shaft systems traverse multiple critical speeds during operation. Due to the significant gyroscopic effect and coupled vibration characteristics of the shaft system, any low-frequency disturbance or uneven stiffness change from the external environment will be transmitted through the housing to the bearing support system, inducing instability in the rotor's dynamic response and generating severe nonlinear vibrations. Flywheel systems commonly employ magnetic levitation bearings to achieve frictionless operation. To ensure electromagnetic efficiency and control precision, the radial clearance between the rotor and stator / capture bearings is typically limited to millimeters or even smaller. In this high-precision scenario, large-amplitude swaying or instantaneous displacement caused by external impacts (such as earthquakes or transportation bumps) can easily lead to mechanical collisions between the rotor and bearings, causing irreversible equipment damage.

[0004] The controller design of magnetic bearings is typically based on specific foundation stiffness and damping models. Traditional vibration isolation solutions, such as rubber bearings, reduce the amplitude of the superstructure by avoiding the site's dominant period. However, under extreme conditions, the vertical amplitude response cannot be ignored, and the lack of effective limiting and energy dissipation grading can lead to the violent impact energy directly affecting the flywheel system and causing it to collapse. In this situation, it is impossible to simultaneously achieve both "stable daily operation" and "controllable extreme conditions."

[0005] In summary, to adapt to a wider range of application sites, flywheel energy storage systems must employ a vibration reduction scheme capable of adaptively adjusting stiffness and effectively controlling amplitude. Existing engineering projects often use rubber pads, spring supports, or dampers between the flywheel body and the foundation to reduce vibration. While these vibration reduction and isolation measures can alleviate vibration to some extent, they generally have the following shortcomings. 1. Simple vibration isolation mechanism: It usually relies on only an elastomer or a single damping element. For example, if the rubber pad is not treated, it will age faster under long-term vertical load and equipment vibration, resulting in a decline in performance. 2. Lack of system coordination: Most vibration isolation devices only consider reducing vibration transmission and do not effectively coordinate with the active control of magnetic bearings, which can easily lead to coupling problems between low frequency and rotor modes; 3. Insufficient adaptability to extreme working conditions: Under conditions such as earthquakes or transportation, a single flexible vibration isolation may cause the outer shell to swing significantly, posing a risk of damage to the gap between the rotor and the outer shell, and lacking limit or self-adaptive functions.

[0006] Therefore, existing measures are insufficient to meet the safety protection requirements of flywheel energy storage systems to avoid external vibrations under complex operating conditions.

[0007] The non-rigid bonding multi-stage vibration reduction and isolation structure proposed in this application is based on the above-mentioned special requirements. Through the non-fixed interface cooperation between the connecting plate and the pre-embedded cover plate, the system sequentially triggers shear, sliding and inclined plane compression shear mechanisms under different amplitudes, ensuring the safety of the magnetic levitation bearing control system in the flywheel shaft system. Summary of the Invention

[0008] The purpose of this invention is to provide a multi-stage vibration reduction and isolation structure and method for a flywheel energy storage system, so as to solve the problems of existing vibration isolation measures, such as simple mechanism, lack of system coordination, and insufficient adaptability to extreme working conditions.

[0009] The technical solution of the present invention is as follows: a multi-stage vibration reduction and isolation structure for a flywheel energy storage system, which reduces vibration of the flywheel energy storage body. The flywheel energy storage body includes a flywheel shaft system and a main body shell. The flywheel shaft system is located inside the main body shell. The multi-stage vibration reduction and isolation structure includes a connecting plate, a viscoelastic material, and a pre-embedded cover plate. The flywheel energy storage body is fixedly installed on the connecting plate by several high-strength bolts. The pre-embedded cover plate is fixed on a concrete base. The connecting plate is located above the pre-embedded cover plate, and the connecting plate and the pre-embedded cover plate together form a mutually meshing gap, which accommodates the viscoelastic layer.

[0010] The flywheel energy storage unit is fixedly installed on the connecting plate by several high-strength bolts, and the pre-embedded cover plate is fixed to the concrete foundation by pre-embedded fixing bolts.

[0011] The connecting plate is made of thick steel plate and is larger than the bottom surface of the flywheel body.

[0012] The embedded cover plate is made of steel plate or cast iron, with a thickness of 20-50mm.

[0013] The lower fixing bolts are expansion bolts or embedded parts with a diameter of M16 to M20.

[0014] The gap between the connecting plate and the embedded cover plate is larger than the area of ​​the viscoelastic layer.

[0015] A limiting flange is provided on the lower surface of the connecting plate.

[0016] Viscoelastic materials are made of block-shaped laminated rubber or high-damping synthetic rubber.

[0017] The significant advantages of this invention are: Graded vibration isolation: It plays its role sequentially under vibration of different amplitudes—the elastic support unit undertakes isolation during small vibrations, the sliding interface unit undergoes relative displacement and consumes energy during medium disturbances, and the limiting and buffering unit intervenes during large disturbances to prevent excessive displacement and absorb energy. System coordination: The flywheel body and vibration isolation device are integrated into a single structure to reduce the transmission of external vibrations to the shaft system during operation, reduce the control pressure on the magnetic bearing, and improve system stability; Extreme operating condition protection: In complex environments such as earthquakes and transportation, the vibration isolation device suppresses large swings of the flywheel body through limiting and buffering mechanisms, ensuring the safety of the gap between the rotor and the housing and avoiding failure; Applicable to multiple scenarios: The device has a compact structure and adjustable parameters, and can be configured according to needs. It is suitable for various application scenarios such as power plants, vehicle-mounted uninterruptible power supplies and other energy storage units. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of an earthquake action model; Figure 2 A schematic diagram of the flywheel body located within a multi-stage vibration damping and isolation device; Figure 3 The flywheel body is in motion within a multi-stage vibration damping and isolation device. Explanation of the attached drawing numbers: 101 Flywheel shaft system, 102 Main body shell, 201 Upper connecting bolt, 202 Connecting plate, 203 Viscoelastic material, 204 Embedded cover plate, 205 Lower fixing bolt. Detailed Implementation

[0019] Many specific details are set forth in the following description to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed below.

[0020] The terminology used in one or more embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of one or more embodiments of this application. The singular forms “a,” “the,” and “the” used in one or more embodiments of this application and in the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” used in one or more embodiments of this application refers to and includes any or all possible combinations of one or more associated listed items.

[0021] It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this application, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this application, and similarly, second may also be referred to as first.

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Figure 1 This diagram illustrates a simplified dynamic model of the multi-stage vibration reduction and isolation device of the present invention under seismic loading. In the model, the flywheel energy storage system is simplified to a concentrated mass M, and the seismic excitation input from the foundation is used as the bottom motion input, which is transmitted to mass M through the vibration reduction and isolation device. Spring Ks represents the equivalent stiffness of the vibration reduction and isolation device, reflecting the overall ability of the device to resist horizontal displacement; damper Cs represents the equivalent damping of the vibration reduction and isolation device, representing the ability of the viscoelastic material's internal friction or frictional sliding structure in the device to dissipate vibration energy.

[0024] The single-degree-of-freedom model described above allows for the analysis of the dynamic characteristics of the flywheel system under earthquake conditions, including its natural period and damping ratio. This provides guidance for selecting parameters of vibration reduction and isolation devices, ensuring that the natural frequency avoids the main excitation frequency band and that the damping ratio is appropriate. Under seismic loading, the spring Ks stores deformation energy and provides restoring force, constraining the flywheel body to near its equilibrium position, while the damper Cs dissipates vibration energy and prevents resonance amplification.

[0025] Figure 2 This diagram shows a cross-sectional view of the overall structure of the flywheel energy storage unit mounted on a multi-stage vibration damping and isolation device. The flywheel energy storage unit includes a flywheel shaft system 101 and a main body shell 102. The flywheel shaft system 101 is located inside the main body shell 102. The flywheel energy storage unit is fixedly mounted on a connecting plate 202 by several high-strength bolts 201, ensuring reliable fixation and uniform stress distribution. The connecting plate 202 is made of thick steel plate (e.g., Q235 carbon steel plate with a thickness of 20-40mm), and its dimensions are slightly larger than the bottom dimensions of the flywheel main body. It is used to transfer the weight of the flywheel to the vibration damping device and serve as an upper rigid support. An embedded cover plate 204 is fixed to a concrete base. Its material is steel plate or cast iron, and its thickness is typically 20-50mm to provide sufficient rigidity and load-bearing capacity. The planar dimensions of the embedded cover plate 204 are determined according to the weight of the flywheel unit, generally in the range of 0.5 to 1.5 meters, and are fixed to the concrete foundation by embedded lower fixing bolts 205; the lower fixing bolts 205 can be expansion bolts or embedded parts with diameters of M16 to M20, so that the embedded cover plate 204 is firmly connected to the concrete foundation and can withstand seismic action and repeated vibration without loosening.

[0026] The embedded cover plate 204 is a load-bearing component with a raised curved surface. The connecting plate 202 is positioned directly above the embedded cover plate 204 and the viscoelastic material 203, corresponding to the raised curved surface of the embedded cover plate 204, and has a recessed curved surface structure on its inner side. Together, they form a pair of interlocking gaps, with a gap in the middle to accommodate the viscoelastic layer 203. Both the connecting plate 202 and the embedded cover plate 204 are made of high-quality steel, and their contact surfaces are machined to form smooth inclined or curved surfaces to ensure uniform friction and stable force during relative sliding. The diameters of the connecting plate 202 and the embedded cover plate 204 are slightly larger than the area of ​​the viscoelastic layer 203, providing ample containment in all horizontal directions.

[0027] An intermediate viscoelastic material 203 is installed between the connecting plate 202 and the embedded cover plate 204, providing the main vibration damping elasticity and energy dissipation element for this device. The viscoelastic material 203 is preferably made of block-shaped laminated rubber or high-damping synthetic rubber, its planar shape matching the inner cavity of the cover plate, and its thickness generally ranging from 30 to 80 mm according to design requirements. The viscoelastic material has a certain adhesive friction force, allowing it to contact the connecting plate 202 and the embedded cover plate 204 without rigid bonding: during assembly, the viscoelastic material 203 is first placed in the groove of the embedded cover plate 204, and then the connecting plate 202 is placed on top, so that the upper and lower surfaces of the rubber block adhere to the inclined surfaces of the two cover plates. Since no adhesive is used for fixing, the rubber layer can slightly slide relative to the cover plate under the action of seismic horizontal forces, thereby providing frictional energy dissipation; to prevent excessive displacement of the viscoelastic material 203 during strong earthquakes, a limiting flange is provided on the lower surface of the connecting plate 202 to ensure that the rubber layer is always covered between the two cover plates.

[0028] Figure 3 The working mechanism of this multi-stage vibration reduction and isolation device under different seismic actions is illustrated below, including: the shear stage under small-amplitude horizontal vibration, the sliding stage under larger vibration, and the inclined plane compression-shear stage under extreme impact. The motion mechanism, structural response characteristics, and energy dissipation mode of each stage are explained in detail below with reference to the illustrations.

[0029] Shearing stage (small amplitude): When the external vibration amplitude is small (e.g., minor vibrations in daily equipment or small earthquakes), the flywheel shaft system 101 and the foundation mainly adapt to relative displacement through the elastic shear deformation of the viscoelastic material 203. At this time, the connecting plate 202 and the embedded cover plate 204 remain relatively stationary, and the friction between the rubber layer and the contact surface of the cover plate is not overcome. The thickness and composition of the rubber layer can adjust the stiffness and damping in this stage.

[0030] Sliding Phase (Medium Amplitude): When an earthquake or impact causes the horizontal shear force to increase sufficiently to overcome the static friction between the rubber layer and the cover plate, the device enters the sliding friction energy dissipation phase. In this phase, the connecting plate 202 begins to slide horizontally relative to the embedded cover plate 204, and the viscoelastic material 203 undergoes sliding displacement relative to the cover plate surface. During this process, interfacial friction provides an energy dissipation mechanism approximating Coulomb damping: sliding friction dissipates vibrational energy as heat while limiting the displacement range transmitted to the flywheel shaft system 101. Due to the conical limiting structure, the connecting plate 202 and the embedded cover plate 204 remain in contact, thus the flywheel body remains controlled and does not become unstable. This effectively dissipates the energy of a moderate-amplitude earthquake. Inclined Shear Stage (Large Amplitude Impact): When encountering a strong earthquake or impact, the relative displacement of the flywheel body further increases, and the connecting plate 202 will undergo relative movement in the inclined area of ​​the embedded cover plate 204, entering the inclined compression-shear coupled deformation stage. At this time, the upper and lower cover plates tend to climb relative to each other along the conical inclined plane, and the connecting plate 202 slides horizontally while climbing, causing the viscoelastic material 203 sandwiched between the inclined planes to undergo combined compression and shear deformation. Due to the existence of the inclined plane angle, the movement process needs to overcome a certain component of gravity, which manifests as the system stiffness transitioning from the initial shear stiffness K1 to the inclined plane compression-shear stiffness K2. The viscoelastic material 203 is compressed and deformed, and significant hysteretic energy dissipation is generated inside it; at the same time, the flywheel body being lifted by the inclined plane is equivalent to doing work on the component of gravity on the inclined plane, and the seismic energy is further dissipated in the displacement to overcome gravity. This stage effectively limits the maximum displacement of the flywheel body, preventing the risk of structural collision or overturning caused by excessive displacement. Once the seismic energy is dissipated, the upper cover plate will automatically slide down the slope and reset under gravity, restoring the flywheel body to its initial center position. The device completes one cycle without compromising its overall performance. It is important to note that the initiation conditions of the slope compression-shear stage depend on the slope of the cover plate's conical surface and the initial gap. During the design phase, the slope angle and rubber thickness are controlled so that this stage only intervenes during major earthquakes. For example, with a smaller slope angle (e.g., 5°), the upper cover plate slides a short distance and then gradually rises, entering the compression-shear energy dissipation phase earlier, which helps control displacement earlier but may slightly increase stiffness during normal small vibrations. With a larger slope angle (e.g., 15°), a larger horizontal slide is allowed before a significant rise.

[0031] Through the above-mentioned multi-stage working mechanism, this device achieves multi-level vibration reduction and isolation nonlinear characteristics throughout the entire vibration response process. Compared with the traditional single-layer rubber vibration isolation pad which only has fixed stiffness and damping, the phased mechanical characteristics of this device significantly broaden the applicable vibration range. (1) This invention achieves automatic adaptation to vibrations of different amplitudes through the progressive stiffness and variable damping characteristics of the three stages of shearing-sliding-compression shearing. (2) Under large impact conditions, a single rubber pad is easily compacted or even damaged due to its limited stroke, while the sliding and inclined plane compression shearing mechanisms of this device provide additional displacement tolerance and energy dissipation pathways, greatly reducing the impact of strong earthquakes. (3) The inclined plane structure acts as a limiter to ensure that the flywheel body will not detach or overturn, and can still automatically reset and maintain functional integrity after a large earthquake.

[0032] The multi-stage vibration reduction and isolation structure of this invention is applicable not only to flywheel energy storage devices fixed on building foundations but also to mobile applications such as vehicles. For example, in vehicle-mounted UPS power systems, flywheel energy storage units are typically placed on the vehicle chassis and need to cope with both continuous vibrations and occasional impacts during driving. When this vibration reduction and isolation device is installed on a vehicle platform, its structure is similar to that of a fixed installation: the pre-embedded cover plate 204 is fixed to the vehicle chassis frame with bolts, and the connecting plate 202 connects to the flywheel shaft system 101, thereby suspending the flywheel in the multi-stage vibration reduction unit. In vehicle applications, due to frequent road vibration sources including acceleration and bumps, the multi-stage characteristics of this device are particularly suitable: small road vibrations are mainly absorbed by the viscoelastic material 203; moderate impacts caused by vehicle starting and braking or small bumps are dissipated through interface sliding; and large impacts (such as emergency braking or collision with speed bumps) trigger the inclined plane compression-shear mechanism, limiting the flywheel sway amplitude and protecting its safety. To enhance the adaptability of mobile carriers under operating conditions, device parameters can be optimized according to vehicle load and vibration characteristics. For example, viscoelastic materials with excellent high and low temperature resistance can be selected to adapt to outdoor temperature changes, the cover plate slope angle and rubber thickness can be adjusted to match the frequency characteristics of the vehicle suspension system, and anti-loosening measures (such as thread sealant, double nut locking, etc.) can be adopted to ensure the reliability of fasteners during long-distance vibration.

[0033] In summary, the multi-stage vibration reduction and isolation device effectively overcomes the bottleneck of existing single-stage vibration isolation elements, which cannot simultaneously address both small vibration isolation and large vibration shock protection, and can greatly improve the safety and reliability of flywheel energy storage equipment in complex vibration environments.

[0034] The above description is merely a preferred embodiment of this patent and is not intended to limit this patent. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this patent shall be included within the scope of protection of this patent.

[0035] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0036] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0037] The preferred embodiments disclosed above are merely illustrative of this application. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this application. These embodiments are selected and specifically described in this application to better explain the principles and practical applications of this application, thereby enabling those skilled in the art to better understand and utilize this application.

Claims

1. A multi-stage vibration reduction and isolation structure for a flywheel energy storage system, used to reduce vibration in the flywheel energy storage body, the flywheel energy storage body comprising a flywheel shaft system (101) and a main body shell (102), the flywheel shaft system (101) being located inside the main body shell (102), characterized in that: The multi-stage vibration reduction and isolation structure includes a connecting plate (202), a viscoelastic material (203), and a pre-embedded cover plate (204). The flywheel energy storage body is fixedly installed on the connecting plate (202) by several high-strength bolts (201). The pre-embedded cover plate (204) is fixed on the concrete base. The connecting plate (202) is located above the pre-embedded cover plate (204), and the connecting plate (202) and the pre-embedded cover plate (204) together form a mutually meshing gap, in which the viscoelastic layer (203) is accommodated.

2. The multi-stage vibration reduction and isolation structure for a flywheel energy storage system according to claim 1, characterized in that: The flywheel energy storage body is fixedly installed on the connecting plate (202) by several high-strength bolts (201), and the pre-embedded cover plate (204) is fixed on the concrete foundation by pre-embedded fixing bolts (205).

3. The multi-stage vibration reduction and isolation structure for a flywheel energy storage system according to claim 2, characterized in that: The connecting plate (202) is made of thick steel plate and is larger than the bottom surface size of the flywheel body.

4. The multi-stage vibration reduction and isolation structure of a flywheel energy storage system according to claim 2, characterized in that: The embedded cover plate (204) is made of steel plate or cast iron, with a thickness of 20-50mm.

5. The multi-stage vibration reduction and isolation structure for a flywheel energy storage system according to claim 2, characterized in that: The lower fixing bolt (205) is an expansion bolt or embedded part with a diameter of M16 to M20.

6. The multi-stage vibration reduction and isolation structure of a flywheel energy storage system according to claim 2, characterized in that: The gap between the connecting plate (202) and the embedded cover plate (204) is larger than the area of ​​the viscoelastic layer (203).

7. The multi-stage vibration reduction and isolation structure for a flywheel energy storage system according to claim 6, characterized in that: A limiting flange is provided on the lower surface of the connecting plate (202).

8. The multi-stage vibration reduction and isolation structure of a flywheel energy storage system according to claim 2, characterized in that: The viscoelastic material (203) is made of block-shaped laminated rubber or high-damping synthetic rubber.

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