Horizontal flywheel energy storage system and system control method

Abstract

The application relates to the technical field of power grids, and discloses a horizontal flywheel energy storage system and a system control method, wherein the system comprises a flywheel energy storage unit, a primary connector, a double-fed motor and a system control unit; the flywheel energy storage unit is rigidly or flexibly connected with a rotor of the double-fed motor through the primary connector; a stator of the double-fed motor is electrically connected with an alternating-current power grid; the system control unit is electrically connected with the flywheel energy storage unit, the primary connector and the double-fed motor; wherein the flywheel energy storage unit, the primary connector and the double-fed motor are horizontally arranged, and the flywheel energy storage unit adopts vacuum sealing. The flywheel energy storage unit, the primary connector and the double-fed motor all adopt horizontal arrangement, can support a larger and heavier flywheel rotor, the rotational inertia of the flywheel rotor is increased, and the capacity of the horizontal flywheel energy storage system for providing rotational inertia to the alternating-current power grid is improved.

Description

Technical Field

[0001] This application relates to the field of power grid technology, and in particular to a horizontal flywheel energy storage system and a system control method. Background Technology

[0002] With the advancement of energy transformation, the proportion of new energy sources in AC power grids continues to rise. However, the power electronic devices widely used in new energy technologies have inherent defects when connected to the grid. Due to their stationary nature, they lack a rotating structure and rotational inertia similar to synchronous machines, making it difficult to actively provide the voltage, frequency support, and damping effect required by the AC power grid. In particular, with the increasing penetration rate of distributed energy, the rotational inertia of the AC power grid is constantly decreasing, increasing the risk of frequency deviation during load or power supply changes, and increasing the power imbalance impact on the system, putting enormous pressure on the safe and stable operation of the power system. Against this backdrop, in order to alleviate the pressure on AC power grid operation and new energy consumption, there is an urgent need for energy storage systems with the ability to support dynamic grid adjustments to improve the efficiency of new energy integration into the AC power grid. Therefore, vertical flywheel energy storage units have been developed. However, vertical flywheel energy storage units are supported by only one bearing, which limits the weight of the flywheel they can bear, resulting in insufficient rotational inertia. Summary of the Invention

[0003] In view of this, this application provides a horizontal flywheel energy storage system and a system control method to solve the technical problem that the existing vertical flywheel energy storage unit is supported by only one bearing, which limits the weight of the flywheel it can bear, resulting in insufficient rotational inertia.

[0004] In a first aspect, this application proposes a horizontal flywheel energy storage system, which includes: a flywheel energy storage unit, a connecting unit, a doubly-fed motor, and a system control unit. The flywheel energy storage unit includes stationary components and rotating components, and the connecting unit includes a primary connector.

[0005] The flywheel energy storage unit is rigidly or flexibly connected to the rotor of the doubly fed motor via the primary connector;

[0006] The stator of the doubly fed motor is electrically connected to the AC power grid;

[0007] The system control unit is electrically connected to the flywheel energy storage unit, the primary connector, and the doubly fed motor;

[0008] The flywheel energy storage unit, the primary connector, and the doubly fed motor are all horizontally arranged, and the flywheel energy storage unit is vacuum sealed.

[0009] Furthermore, the connection unit further includes a secondary connector, and the system control unit is electrically connected to the secondary connector;

[0010] The secondary connector is connected between the flywheel energy storage unit and the primary connector;

[0011] The secondary connector uses a permanent magnet continuously variable transmission or a gear transmission.

[0012] Furthermore, the primary connector is a coupling or a magnetic coupler.

[0013] Furthermore, the stationary component includes: a vacuum housing, a base frame, a front bearing assembly, a rear bearing assembly, a front gas seal assembly, and a rear gas seal assembly; the rotating component is a flywheel rotor; the system control unit is electrically connected to the flywheel rotor.

[0014] The vacuum housing is connected to the front gas seal assembly, the rear gas seal assembly, the front bearing assembly, and the rear bearing assembly flanges to form an integral component. The integral component is mounted on the base frame, and the flywheel rotor is mounted inside the vacuum housing.

[0015] The front bearing assembly is used to support the front shaft diameter of the flywheel rotor, and the rear bearing assembly is used to support the rear shaft diameter of the flywheel rotor.

[0016] The flywheel rotor is connected to the front bearing assembly via a vacuum seal through the front air seal assembly, and the front air seal assembly is used to connect the vacuum housing to the outer shell of the front bearing assembly;

[0017] The flywheel rotor is connected to the rear bearing assembly via a vacuum seal assembly, and the rear vacuum seal assembly is used to connect the vacuum housing to the outer shell of the rear bearing assembly.

[0018] Furthermore, the front bearing assembly, the rear bearing assembly, and the vacuum housing are all mounted on the base frame.

[0019] Furthermore, the flywheel energy storage unit also includes: a front bearing housing guide slider and a vacuum housing guide slider, wherein the front bearing housing guide slider is installed between the base frame and the front bearing assembly, and the vacuum housing guide slider is installed between the base frame and the vacuum housing.

[0020] Furthermore, the flywheel rotor, the vacuum housing, the front gas seal assembly, the rear gas seal assembly, the front bearing assembly, and the rear bearing assembly are coaxially arranged.

[0021] Furthermore, the horizontal flywheel energy storage system also includes: a lubrication and cooling unit, a first pipe assembly, and a second pipe assembly, wherein the system control unit is electrically connected to the lubrication and cooling unit;

[0022] The lubrication and cooling unit is connected to the front bearing assembly via the first pipe assembly to provide a lubrication and cooling medium to the front bearing assembly;

[0023] The lubrication and cooling unit is connected to the rear bearing assembly via the second piping assembly to provide a lubrication and cooling medium to the rear bearing assembly.

[0024] Furthermore, the horizontal flywheel energy storage system also includes: a high-voltage top shaft unit, a third pipeline assembly, and a fourth pipeline assembly, and the system control unit is electrically connected to the high-voltage top shaft unit;

[0025] The high-pressure jacking unit is connected to the housing of the front bearing assembly through the third pipeline assembly to provide high-pressure jacking oil to the front bearing assembly. The oily medium provided by the high-pressure jacking unit to the front bearing assembly is used to lift the front shaft of the flywheel rotor with a first pressure. The lubrication and cooling unit provides the front bearing assembly with an oily medium at a second pressure.

[0026] The high-pressure jacking unit is connected to the housing of the rear bearing assembly through the fourth pipe assembly to provide the rear bearing assembly with an oily medium at a first pressure. The oily medium provided by the high-pressure jacking unit to the rear bearing assembly is used to lift the rear shaft of the flywheel rotor with the first pressure. The lubrication and cooling unit provides the rear bearing assembly with an oily medium at a second pressure.

[0027] Wherein, the first pressure is greater than the second pressure.

[0028] Furthermore, the base frame, the flywheel rotor, the vacuum housing, the front bearing assembly, the rear bearing assembly, the front gas seal assembly, and the rear gas seal assembly are pre-assembled and transported as a single unit.

[0029] Furthermore, the horizontal flywheel energy storage system also includes: a vacuum unit and a vacuum detector; the system control unit is electrically connected to the vacuum unit and the vacuum detector; the vacuum detector is used to detect the vacuum inside the flywheel energy storage unit; the vacuum unit is connected to the flywheel energy storage unit to extract a vacuum from the flywheel energy storage unit.

[0030] Secondly, this application proposes a system control method, which is applicable to the horizontal flywheel energy storage system described in any one of the first aspects, the method comprising:

[0031] Obtain the operating mode of the horizontal flywheel energy storage system;

[0032] If the working mode is standby mode, then obtain the frequency deviation value between the instantaneous frequency of the AC power grid and the preset rated frequency of the power grid.

[0033] If the frequency deviation value is greater than 0, the doubly fed motor of the horizontal flywheel energy storage system is controlled to enable the flywheel energy storage unit of the horizontal flywheel energy storage system to store energy.

[0034] If the frequency deviation value is not equal to 0, the doubly fed motor of the horizontal flywheel energy storage system is controlled so that the flywheel energy storage unit of the horizontal flywheel energy storage system provides inertial support for the AC power grid.

[0035] Implementing the embodiments of this application will have the following beneficial effects:

[0036] The horizontal flywheel energy storage system of this application includes: a flywheel energy storage unit, a primary connector, a doubly-fed motor, and a system control unit; the flywheel energy storage unit is rigidly or flexibly connected to the rotor of the doubly-fed motor through the primary connector; the stator of the doubly-fed motor is electrically connected to the AC power grid; the system control unit is electrically connected to the flywheel energy storage unit, the primary connector, and the doubly-fed motor; wherein, the flywheel energy storage unit, the primary connector, and the doubly-fed motor are all horizontally arranged, and the flywheel energy storage unit is vacuum-sealed. Compared to a vertical flywheel energy storage unit, in this application, the flywheel energy storage unit, the primary connector, and the doubly-fed motor are all horizontally arranged, which can support a larger and heavier flywheel rotor, thereby increasing the rotational inertia of the flywheel rotor and improving the ability of the horizontal flywheel energy storage system to provide rotational inertia to the AC power grid. Furthermore, the flywheel energy storage unit adopts vacuum sealing, which reduces the air resistance of the flywheel rotor, improves energy conversion efficiency, avoids energy loss caused by air friction, extends the service life of the flywheel energy storage unit, and is not subject to external air erosion, reducing the occurrence of rust and oxidation of the flywheel rotor. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] in:

[0039] Figure 1 This is a structural block diagram of a horizontal flywheel energy storage system in one embodiment;

[0040] Figure 2 This is a schematic diagram of the horizontal flywheel energy storage system of this application;

[0041] Figure 3This is a structural schematic diagram of the horizontal flywheel energy storage system of this application from another angle;

[0042] Figure 4 This is a flowchart illustrating the system control method of this application;

[0043] Figure 5 This is another flowchart illustrating the system control method of this application;

[0044] Figure 6 This is another flowchart illustrating the system control method of this application. Detailed Implementation

[0045] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0046] Please see Figures 1 to 3 In one embodiment, this application proposes a horizontal flywheel energy storage system, which includes: a flywheel energy storage unit 1, a connection unit 2, a doubly-fed motor 3, and a system control unit. The flywheel energy storage unit 1 includes a stationary component and a rotating component, and the connection unit 2 includes a primary connector.

[0047] The flywheel energy storage unit 1 is rigidly or flexibly connected to the rotor of the doubly fed motor 3 through the primary connector;

[0048] The stator of the doubly fed motor 3 is electrically connected to the AC power grid 8;

[0049] The system control unit is electrically connected to the flywheel energy storage unit 1, the primary connector and the doubly fed motor 3;

[0050] The flywheel energy storage unit 1, the primary connector, and the doubly fed motor 3 are all horizontally arranged, and the flywheel energy storage unit 1 is vacuum sealed.

[0051] Compared to the vertical flywheel energy storage unit 1, in this application, the flywheel energy storage unit 1, the primary connector, and the doubly-fed motor 3 are all horizontally arranged, which can support a larger and heavier flywheel rotor 11, increasing the rotational inertia of the flywheel rotor 11 and thus improving the ability of the horizontal flywheel energy storage system to provide rotational inertia to the AC grid. Furthermore, the flywheel energy storage unit 1 is vacuum-sealed, reducing air resistance of the flywheel rotor 11, improving energy conversion efficiency, avoiding energy loss due to air friction, extending the service life of the flywheel energy storage unit 1, and preventing corrosion from external air, thus reducing rust and oxidation of the flywheel rotor 11.

[0052] The flywheel energy storage unit 1, the primary connector, and the doubly fed motor 3 are all horizontally arranged, and the shafts of the flywheel energy storage unit 1, the primary connector, and the doubly fed motor 3 are not perpendicular to the ground.

[0053] Doubly-fed motor 3 is both an unloaded doubly-fed motor and a doubly-fed generator without a prime mover. Doubly-fed motor 3 has energy storage, power generation, and phase regulation functions.

[0054] The system control unit includes: a main control subunit, a flywheel control subunit, a motor control subunit 41, and a connection control subunit. The main control subunit controls the operation of the flywheel control subunit, the motor control subunit 41, and the connection control subunit. The flywheel control subunit controls the operation of the flywheel energy storage unit 1. The connection control subunit controls the operation of the primary connector. The motor control subunit 41 controls the operation of the doubly-fed motor 3.

[0055] The motor control subunit 41 can be selected from existing technologies, which will not be elaborated here.

[0056] Optionally, the main control subunit, flywheel control subunit, motor control subunit 41 and connection control subunit can all be configured as independent structures (for example, by making them into independent chips and installing the chips in computer equipment or industrial control computers). The chip is obviously a type of hardware, and the chip, which is of the type of hardware, is installed in computer equipment or industrial control computers, which are of the type of hardware.

[0057] Please see Figure 1 and Figure 2 The machine-side converter in the doubly fed converter of the motor control subunit 41 is installed on the rotor side of the doubly fed motor 3, and the grid-side converter of the doubly fed converter is directly connected to the AC power grid 8.

[0058] The motor control subunit 41 is used to detect and receive signals, and control the doubly fed motor 3 to transfer inertia and energy to the AC power grid 8.

[0059] The working principle of the horizontal flywheel energy storage system is as follows: When the instantaneous frequency of the AC power grid 8 is greater than the preset rated frequency, the doubly-fed motor 3 draws electrical energy from the AC power grid 8 to increase the rotational speed of the flywheel rotor 11 of the flywheel energy storage unit 1, thereby enabling the flywheel energy storage unit 1 of the horizontal flywheel energy storage system to store energy; when the instantaneous frequency of the AC power grid 8 is not equal to the preset rated frequency, the doubly-fed motor 3 of the horizontal flywheel energy storage system is controlled to reduce the rotational speed of the flywheel rotor 11 of the flywheel energy storage unit 1, thereby providing inertial support for the AC power grid 8.

[0060] Flywheel energy storage unit 1 is a unit that uses flywheel energy storage technology to store and release energy.

[0061] Flywheel energy storage technology is an energy storage technology that stores energy in the form of kinetic energy. It achieves energy storage / release by using an electric motor / generator to drive a rotor to accelerate / decelerate. The main advantages of flywheel energy storage are its rapid climbing ability, high energy conversion efficiency, and long service life. It also has unique advantages in providing ancillary services, such as inertia and frequency regulation. Furthermore, flywheels have no geographical limitations, can be easily installed, and are easy to promote and replicate on a large scale.

[0062] In one embodiment, the connection unit 2 further includes a secondary connector, and the system control unit is electrically connected to the secondary connector;

[0063] The secondary connector is connected between the flywheel energy storage unit 1 and the primary connector;

[0064] The secondary connector employs a permanent magnet continuously variable transmission (CVT) or a gear transmission. By using a CVT or gear transmission in the secondary connector, the ratio between the flywheel rotor 11 speed and the doubly-fed motor 3 speed can be adjusted, resulting in greater flexibility and precision in adjusting this ratio. This allows for better adaptation to different working scenarios and requirements, optimizing the system's operating state. Secondly, it enables finer speed matching and control, improving the overall system efficiency and performance, and ensuring more efficient and stable energy transmission and conversion. Furthermore, this adjustable ratio provides more possibilities for system operation and optimization, helping to improve the system's adaptability and reliability, and expanding its application range and applicable environments.

[0065] In one embodiment, the primary connector employs a coupling or a magnetic coupler. The advantages of a coupling include: it can securely connect two shafts and transmit torque; it can compensate for shaft coaxiality and angular misalignment to a certain extent; and it can be used in various types of equipment and operating conditions. The advantages of a magnetic coupler include: reduced wear and mechanical failures, low maintenance costs; effective isolation of vibration transmission between the driving and driven shafts; automatic slippage under excessive load, providing protection; quiet operation; and good adaptability to harsh working environments. The use of a coupling or magnetic coupler in the primary connector improves the stability and reliability of the positive system.

[0066] In one embodiment, the stationary component includes: a vacuum housing 12, a base frame 18, a front bearing assembly 14, a rear bearing assembly 15, a front air seal assembly 16, and a rear air seal assembly 17; the rotating component is a flywheel rotor 11; and the system control unit is electrically connected to the flywheel rotor 11.

[0067] The vacuum housing 12 is flange-connected to the front gas seal assembly 16, the rear gas seal assembly 17, the front bearing assembly 14, and the rear bearing assembly 15 to form an integral component. The integral component is mounted on the base frame 18, and the flywheel rotor 11 is mounted inside the vacuum housing 12.

[0068] The front bearing assembly 14 is used to support the front shaft diameter of the flywheel rotor 11, and the rear bearing assembly 15 is used to support the rear shaft diameter of the flywheel rotor 11.

[0069] The flywheel rotor 11 is connected to the front bearing assembly 14 via the front air seal assembly 16, and the front air seal assembly 16 is used to connect the vacuum housing 12 to the outer shell of the front bearing assembly 14.

[0070] The flywheel rotor 11 is connected to the rear bearing assembly 15 via the rear air seal assembly 17, and the rear air seal assembly 17 is used to connect the vacuum housing 12 to the outer shell of the rear bearing assembly 15.

[0071] This embodiment utilizes the front bearing assembly 14 and the rear bearing assembly 15 to provide stable support, ensuring that the flywheel rotor 11 can rotate smoothly and stably, reducing friction and resistance during rotation, and improving energy conversion efficiency. Secondly, it helps to reduce wear and energy loss, extending the service life of the equipment. Furthermore, this support method can enhance the reliability and stability of the entire system operation, ensuring the performance of the flywheel energy storage device during operation. The flywheel rotor 11 is connected to the front bearing assembly 14 via the front air seal assembly 16, which connects the vacuum housing 12 to the outer shell of the front bearing assembly 14. The flywheel rotor 11 is connected to the rear bearing assembly 15 via the rear air seal assembly 17, which connects the vacuum housing 12 to the outer shell of the rear bearing assembly 15. This effectively holds the vacuum housing 12 in place, significantly reducing deformation of the vacuum housing 12 under atmospheric pressure, thus improving the vacuum housing 12's resistance to atmospheric pressure. The vacuum housing 12 increases the vacuum space for the flywheel rotor 11, reducing the wind resistance loss of the flywheel rotor 11.

[0072] The front bearing assembly 14 adopts any one of the following: sliding bearing, air bearing, and magnetic bearing.

[0073] The rear bearing assembly 15 adopts any one of the following: sliding bearing, air bearing, and magnetic bearing.

[0074] Sliding bearings operate under sliding friction. Air bearings are bearings that use gas pressure to suspend the shaft. Magnetic bearings, also known as electromagnetic levitation bearings or magnetic bearings, are a new type of high-performance bearing that uses magnetic force to suspend the rotor in the air.

[0075] Both the front air seal assembly 16 and the rear air seal assembly 17 are air seal assemblies.

[0076] The vacuum housing 12 has a cavity inside, which is a vacuum space, and the flywheel rotor 11 is located inside the cavity.

[0077] Optionally, the vacuum housing 12 is divided into an upper housing and a lower housing. The upper housing and the lower housing are combined to form a complete housing.

[0078] Optionally, the stationary component includes: a housing support 13, which is mounted on the base frame 18 and located between the front bearing assembly 14 and the rear bearing assembly 15, and the vacuum housing 12 is mounted on the housing support 13.

[0079] The housing support 13 guides the vacuum housing 12 to expand radially to both sides when the vacuum housing 12 is heated and expands, keeping the housing coaxial with the flywheel rotor 11.

[0080] The shape and structure of the vacuum housing 12 and the housing support 13 can be set according to requirements, and will not be described in detail here.

[0081] A gas seal assembly is a device used to seal gases. It is typically used in equipment or systems that require control of gas leaks or maintenance of a specific gas environment. The specific structure and design of a gas seal assembly vary depending on the application. Its function is to prevent abnormal gas leakage at certain points, maintain normal system operation, and ensure a specific gas state. A gas seal assembly may include components such as seals, gaskets, and sealing rings.

[0082] The rotation seal of the vertical flywheel energy storage unit 1 uses a rubber ring seal, which results in high contact friction loss and is prone to overheating and damage. To solve this problem, the flywheel energy storage unit 1, the primary connector, and the doubly fed motor 3 of this application are all horizontally arranged. Moreover, the vacuum seal of this application, while being able to support a larger and heavier flywheel rotor 11, can also avoid the problems caused by the rubber ring seal in the rotation seal of the vertical flywheel energy storage unit 1.

[0083] Both the front bearing assembly 14 and the rear bearing assembly 15 employ sliding bearing assemblies. Sliding bearing assemblies are components that provide the common functions of sliding bearings. Sliding bearing assemblies can be selected from existing technologies according to requirements, and will not be elaborated upon here.

[0084] A sliding bearing is a bearing that operates under sliding friction. Sliding bearings operate smoothly, reliably, and quietly. Under liquid lubrication conditions, the sliding surfaces are separated by lubricating oil, preventing direct contact and significantly reducing friction loss and surface wear. The oil film also has a certain vibration-absorbing capacity. However, they have relatively high starting friction resistance.

[0085] In one embodiment, the front bearing assembly 14, the rear bearing assembly 15, and the vacuum housing 12 are all mounted on the base frame 18. The base frame 18 supports the sliding bearing assembly / flywheel rotor 11, the vacuum housing 12, etc., and fixes the installed and adjusted positions of each component.

[0086] The shape and structure of the base frame 18 can be set according to requirements, and will not be elaborated here.

[0087] Optionally, the doubly fed motor 3 is mounted on the base frame 18.

[0088] The base frame 18 is mounted on the ground, and the front bearing assembly 14, the rear bearing assembly 15 and the vacuum housing 12 are all mounted on the side of the base frame 18 away from the ground.

[0089] Optionally, the flywheel energy storage unit 1 further includes: a first inclined shim, a second inclined shim, and a third inclined shim. The first inclined shim is disposed between the front bearing assembly 14 and the ground, the second inclined shim is disposed between the rear bearing assembly 15 and the ground, and the third inclined shim is disposed between the doubly fed motor 3 and the ground.

[0090] Optionally, the first, second, and third inclined shims are located between the base frame 18 and the ground.

[0091] In one embodiment, the flywheel energy storage unit 1 further includes a front bearing housing guide slider and a vacuum housing guide slider. The front bearing housing guide slider is installed between the base frame 18 and the front bearing assembly 14, and the vacuum housing guide slider is installed between the base frame 18 and the vacuum housing 12. The front bearing housing guide slider and the vacuum housing guide slider allow the flywheel rotor 11 and the vacuum housing 12 to expand or contract axially during thermal expansion and contraction.

[0092] Both the front bearing housing guide slider and the vacuum housing guide slider use guide sliders. The guide slider can be selected from existing technologies according to requirements, which will not be elaborated here.

[0093] In one embodiment, the flywheel rotor 11, the vacuum housing 12, the front air seal assembly 16, the rear air seal assembly 17, the front bearing assembly 14, and the rear bearing assembly 15 are coaxially arranged. This coaxial arrangement ensures that components such as the flywheel rotor 11 maintain a high degree of concentricity during rotation, reducing eccentricity and vibration, and improving operational accuracy and stability. This design not only adapts to temperature changes, reduces stress concentration, maintains structural integrity, and improves reliability, but also enhances operational accuracy, optimizes power transmission, strengthens overall structural integrity, reduces wear, and facilitates installation and maintenance.

[0094] The flywheel rotor 11, the vacuum housing 12, the front gas seal assembly 16, the rear gas seal assembly 17, the front bearing assembly 14, and the rear bearing assembly 15 are coaxially arranged, that is, the rotation axis of the flywheel rotor 11, the central axis of the vacuum housing 12, the rotation axis of the front bearing assembly 14, and the rotation axis of the rear bearing assembly 15 are all located on the same straight line.

[0095] In one embodiment, the horizontal flywheel energy storage system further includes: a lubrication and cooling unit 10, a first pipe assembly, and a second pipe assembly, wherein the system control unit is electrically connected to the lubrication and cooling unit 10;

[0096] The lubrication and cooling unit 10 is connected to the front bearing assembly 14 through the first pipe assembly to provide lubrication and cooling medium to the front bearing assembly 14;

[0097] The lubrication and cooling unit 10 is connected to the rear bearing assembly 15 via the second pipe assembly to provide lubrication and cooling medium to the rear bearing assembly 15. The lubrication and cooling medium plays a crucial role, significantly reducing frictional losses between components due to their mutual movement, resulting in smoother and more efficient equipment operation. Simultaneously, it has excellent cooling properties, effectively removing heat generated by friction to prevent excessive temperature from adversely affecting the equipment. This ensures stable operation of the equipment within a suitable temperature range, extends its service life, and guarantees the reliable operation of the entire system.

[0098] Oil can be used as the lubricating and cooling medium.

[0099] The first piping assembly includes an oil inlet pipe and an oil outlet pipe. The oil inlet pipe connects the lubrication and cooling unit 10 and the front bearing assembly 14 to supply lubrication and cooling medium to the front bearing assembly 14. The oil outlet pipe connects the lubrication and cooling unit 10 and the front bearing assembly 14 to return the lubrication and cooling medium from the front bearing assembly 14 to the lubrication and cooling unit 10. This provides a flowing lubrication and cooling medium to the front bearing assembly 14.

[0100] The second piping assembly includes an oil inlet pipe and an oil outlet pipe. The oil inlet pipe connects the lubrication and cooling unit 10 and the rear bearing assembly 15 to supply lubrication and cooling medium to the rear bearing assembly 15. The oil outlet pipe connects the lubrication and cooling unit 10 and the rear bearing assembly 15 to return the lubrication and cooling medium from the rear bearing assembly 15 to the lubrication and cooling unit 10. This provides a flowing lubrication and cooling medium to the rear bearing assembly 15.

[0101] The lubrication and cooling unit 10 includes a first storage component and a first power component. The system control unit is electrically connected to the first power component to control the first power component to drive the lubricating and cooling medium in the first storage component to the oil inlet pipe of the first pipeline assembly and the oil inlet pipe of the second pipeline assembly.

[0102] In one embodiment, the horizontal flywheel energy storage system further includes: a high-voltage top shaft unit, a third pipeline assembly, and a fourth pipeline assembly, wherein the system control unit is electrically connected to the high-voltage top shaft unit;

[0103] The high-pressure jacking unit is connected to the housing of the front bearing assembly 14 through the third pipeline assembly to provide high-pressure jacking oil to the front bearing assembly 14. The oily medium provided by the high-pressure jacking unit to the front bearing assembly 14 is used to lift the front shaft of the flywheel rotor 11 with a first pressure. The lubrication and cooling unit 10 provides the front bearing assembly 14 with an oily medium at a second pressure.

[0104] The high-pressure jacking unit is connected to the housing of the rear bearing assembly 15 through the fourth pipe assembly to provide the rear bearing assembly 15 with an oily medium at a first pressure. The oily medium provided by the high-pressure jacking unit to the rear bearing assembly 15 is used to lift the rear shaft of the flywheel rotor 11 with the first pressure. The lubrication and cooling unit 10 provides the rear bearing assembly 15 with an oily medium at a second pressure.

[0105] Wherein, the first pressure is greater than the second pressure. An oily medium at the first pressure is supplied to the front bearing assembly 14, and an oily medium at the first pressure is supplied to the rear bearing assembly 15, thereby lifting the shaft of the flywheel rotor 11 and reducing friction.

[0106] Optionally, the third piping assembly includes an oil inlet pipe, in which case the third piping assembly shares an oil outlet pipe with the first piping assembly.

[0107] Optionally, the third pipeline assembly includes an oil inlet pipe and an oil outlet pipe, in which case the oil outlet pipe of the third pipeline assembly is set independently from the oil outlet pipe of the first pipeline assembly.

[0108] Optionally, the fourth pipeline assembly includes an inlet pipe and an outlet pipe, in which case the outlet pipe of the second pipeline assembly and the fourth pipeline assembly share an outlet pipe that is set independently.

[0109] The high-pressure jacking unit includes a second storage component and a second power component. The system control unit is electrically connected to the second power component to control the second power component to drive the oil medium in the second storage component to the oil inlet pipes of the third and fourth pipeline components.

[0110] In another embodiment of this example, the high-pressure jacking unit employs a pressure booster 111; the lubrication and cooling unit 10 is connected to the housing of the front bearing assembly 14 via the third piping assembly to provide the front bearing assembly 14 with an oily medium at a first pressure; the lubrication and cooling unit 10 is connected to the housing of the rear bearing assembly 15 via the fourth piping assembly to provide the rear bearing assembly 15 with an oily medium at a third pressure. The pressure booster 111 increases the pressure in the oil inlet pipe of the third piping assembly, and the pressure booster 111 also increases the pressure in the oil inlet pipe of the fourth piping assembly.

[0111] In one embodiment, the base frame 18, the flywheel rotor 11, the vacuum housing 12, the front bearing assembly 14, the rear bearing assembly 15, the front air seal assembly 16, and the rear air seal assembly 17 are pre-assembled and transported as a single unit. Pre-assembly followed by integrated transport solves on-site installation challenges and significantly improves efficiency.

[0112] In one embodiment, the horizontal flywheel energy storage system further includes a vacuum unit 19 and a vacuum detector. The system control unit is electrically connected to the vacuum unit 19 and the vacuum detector. The vacuum detector is used to detect the vacuum inside the flywheel energy storage unit 1. The vacuum unit 19 is connected to the flywheel energy storage unit 1 to evacuate the flywheel energy storage unit 1. Evacuating the flywheel energy storage unit 1 through the vacuum unit 19 provides a basis for vacuum sealing of the flywheel energy storage unit 1.

[0113] Vacuum unit 19 may employ a vacuum pump to extract air from the accommodating cavity of vacuum housing 12, thereby creating and maintaining a vacuum within the accommodating cavity. A vacuum detector is mounted on the inner wall of the accommodating cavity of vacuum housing 12 to detect vacuum data within the cavity, using the detected data as vacuum detection data.

[0114] Please see Figure 4 In one embodiment, this application proposes a system control method applicable to the horizontal flywheel energy storage system described in any of the preceding claims, the method comprising:

[0115] S1: Obtain the operating mode of the horizontal flywheel energy storage system;

[0116] Optionally, the operating mode of the horizontal flywheel energy storage system can be obtained from a preset storage space.

[0117] The horizontal flywheel energy storage system operates in either standby or ready mode.

[0118] Understandably, in the ready mode, the horizontal flywheel energy storage system cannot provide inertial support for the AC power grid 8.

[0119] S2: If the working mode is standby mode, then obtain the frequency deviation value between the instantaneous frequency of the AC power grid 8 and the preset rated frequency of the power grid.

[0120] Specifically, if the working mode is standby mode, it means that the pre-stored energy of the flywheel energy storage unit 1 has met the requirements for providing inertia support. Therefore, the frequency deviation value between the instantaneous frequency of the AC power grid 8 and the preset rated frequency of the power grid is obtained.

[0121] The instantaneous frequency of the power grid is the AC power supply frequency of the AC power grid 8, which is detected in real time.

[0122] The preset rated frequency of the power grid is the rated AC power supply frequency of the AC power grid 8. Optionally, the preset rated frequency of the power grid is 50 Hz.

[0123] Specifically, the instantaneous frequency of the power grid is subtracted from the preset rated frequency of the power grid, and the resulting data is used as the frequency deviation value.

[0124] S3: If the frequency deviation value is greater than 0, then the doubly fed motor 3 of the horizontal flywheel energy storage system is controlled so that the flywheel energy storage unit 1 of the horizontal flywheel energy storage system stores energy.

[0125] Specifically, if the frequency deviation value is greater than 0, it indicates that the active power of the AC power grid 8 is excessive, that is, the load of the AC power grid 8 is insufficient. Therefore, by controlling the doubly fed motor 3 of the horizontal flywheel energy storage system, the rotational speed of the flywheel rotor 11 of the flywheel energy storage unit 1 of the horizontal flywheel energy storage system is increased, so as to store energy in the flywheel energy storage unit 1.

[0126] S4: If the frequency deviation value is not equal to 0, then by controlling the doubly fed motor 3 of the horizontal flywheel energy storage system, the flywheel energy storage unit 1 of the horizontal flywheel energy storage system provides inertial support for the AC power grid 8.

[0127] Specifically, if the frequency deviation value is not equal to 0, it means that the instantaneous frequency of the AC power grid 8 does not meet the preset requirements (the preset rated frequency of the power grid), and the AC power grid 8 needs to be frequency regulated. By controlling the doubly fed motor 3 of the horizontal flywheel energy storage system, the rotational speed of the flywheel rotor 11 of the flywheel energy storage unit 1 of the horizontal flywheel energy storage system is reduced to provide inertial support for the AC power grid 8 and realize the inertial response of the AC power grid 8, so as to delay the rate of change of the AC power supply frequency of the AC power grid 8 and prevent the AC power supply frequency of the AC power grid 8 from dropping rapidly.

[0128] Compared to the vertical flywheel energy storage unit 1, in this embodiment, the flywheel energy storage unit 1, the primary connector, and the doubly fed motor 3 are all horizontally arranged, which can support a larger and heavier flywheel rotor 11, thereby increasing the rotational inertia of the flywheel rotor 11 and improving the ability of the horizontal flywheel energy storage system to provide rotational inertia to the AC grid. Furthermore, the flywheel energy storage unit 1 employs vacuum sealing, reducing air resistance of the flywheel rotor 11, improving energy conversion efficiency, avoiding energy loss due to air friction, extending the service life of the flywheel energy storage unit 1, and preventing corrosion from external air, thus reducing rust and oxidation of the flywheel rotor 11. In standby mode, it can flexibly provide inertial support to the AC power grid 8 based on frequency deviation, helping to maintain grid frequency stability and enhancing grid reliability and stability. In standby mode, it can draw energy from the AC power grid 8 and store it in the flywheel energy storage unit 1, achieving effective energy allocation and storage, improving energy utilization efficiency, and providing a certain energy reserve and regulation capability for the AC power grid 8 under different operating conditions, which is beneficial to ensuring the continuous and stable operation of the power grid.

[0129] Please see Figure 5 In one embodiment, the method further includes:

[0130] S51: Obtain the actual energy storage ratio of the flywheel energy storage unit 1 of the horizontal flywheel energy storage system;

[0131] Specifically, the actual energy storage ratio of the flywheel energy storage unit 1 of the horizontal flywheel energy storage system can be obtained from the flywheel control subunit of the system control unit of the horizontal flywheel energy storage system.

[0132] The actual energy storage ratio is the real-time energy storage ratio of flywheel energy storage unit 1.

[0133] S52: If the actual energy storage ratio is within the preset ratio range, then the working mode of the horizontal flywheel energy storage system is determined to be the standby mode;

[0134] Specifically, if the actual energy storage ratio is within the preset ratio range, it means that the pre-stored energy of the flywheel energy storage unit 1 has met the requirements for providing inertia support. Therefore, the working mode of the horizontal flywheel energy storage system is determined to be the standby mode.

[0135] S53: If the actual energy storage ratio is outside the preset ratio range, the working mode of the horizontal flywheel energy storage system is determined to be the preparation mode.

[0136] Specifically, if the actual energy storage ratio is outside the preset ratio range, it means that the pre-stored energy of the flywheel energy storage unit 1 does not meet the requirements for providing inertia support. Therefore, the working mode of the horizontal flywheel energy storage system is determined to be the preparation mode.

[0137] S54: If the working mode is the preparation mode, then control the doubly fed motor 3 of the horizontal flywheel energy storage system so that the flywheel energy storage unit 1 of the horizontal flywheel energy storage system stores energy.

[0138] Optionally, if the working mode is the preparation mode, the doubly fed motor 3 of the horizontal flywheel energy storage system is controlled to draw energy from the AC power grid 8 to increase the rotational speed of the flywheel rotor 11 of the flywheel energy storage unit 1 of the horizontal flywheel energy storage system, so as to store energy in the flywheel energy storage unit 1.

[0139] Optionally, if the working mode is the preparation mode, the doubly fed motor 3 of the horizontal flywheel energy storage system is controlled to draw energy from other power sources (power sources other than AC grid 8) to increase the speed of the flywheel rotor 11 of the flywheel energy storage unit 1 of the horizontal flywheel energy storage system, so as to realize the storage of energy in the flywheel energy storage unit 1.

[0140] This embodiment achieves automated control of the horizontal flywheel energy storage system by setting the operating mode to standby mode when the actual energy storage ratio is within a preset range to provide inertial support for the AC power grid 8, and controlling the doubly-fed motor 3 of the horizontal flywheel energy storage system to enable the flywheel energy storage unit 1 of the horizontal flywheel energy storage system to store energy when the operating mode is the ready mode. Furthermore, by setting the operating mode to standby mode when the actual energy storage ratio is within a preset range to provide inertial support for the AC power grid 8, the stability of the inertial support provided by the horizontal flywheel energy storage system is improved.

[0141] Please see Figure 6 In one embodiment, the method further includes:

[0142] S61: Obtain the vacuum detection data of the flywheel energy storage unit 1 of the horizontal flywheel energy storage system;

[0143] Specifically, the vacuum detection data obtained by the vacuum detector of the horizontal flywheel energy storage system from the flywheel energy storage unit 1 is acquired in real time.

[0144] S62: Determine whether the vacuum detection data is within the shutdown threshold range. If it is within the shutdown threshold range, control the horizontal flywheel energy storage system to shut down.

[0145] Specifically, it is determined whether the vacuum detection data is within the shutdown threshold range, that is, whether a shutdown is necessary. If it is within the shutdown threshold range, it means that the vacuum seal of the flywheel energy storage unit 1 does not meet the working requirements of the flywheel rotor 11. If the flywheel rotor 11 continues to work, it may lead to an accident or equipment damage. Therefore, the horizontal flywheel energy storage system is shut down to provide a basis for maintenance.

[0146] S63: Determine whether the vacuum detection data is within the abnormal vacuum data range. If it is within the abnormal vacuum data range, control the vacuum unit 19 of the horizontal flywheel energy storage system to draw vacuum from the flywheel energy storage unit 1 according to the vacuum detection data.

[0147] Specifically, it is determined whether the vacuum detection data is within the abnormal vacuum data range, that is, whether the power of the vacuum unit 19 of the horizontal flywheel energy storage system needs to be adjusted. If it is within the abnormal vacuum data range, it means that the power of the vacuum unit 19 of the horizontal flywheel energy storage system needs to be adjusted to ensure that the vacuum seal of the flywheel energy storage unit 1 better meets the operating requirements of the flywheel rotor 11. Therefore, a control command is generated based on the vacuum detection data, and the vacuum unit 19 of the horizontal flywheel energy storage system is controlled to draw vacuum from the flywheel energy storage unit 1.

[0148] This embodiment enables precise control of the horizontal flywheel energy storage system by analyzing vacuum detection data. When the vacuum detection data is within the shutdown threshold range, the system is shut down promptly, ensuring its safety and stability and preventing potential risks from escalating. Conversely, when the vacuum detection data is within the abnormal vacuum range, the vacuum unit 19 can be precisely controlled to evacuate the flywheel energy storage unit 1 based on the specific data. This helps maintain the rationality and stability of the vacuum environment within the system, ensuring that the flywheel energy storage unit 1 can operate normally under suitable vacuum conditions, thereby improving the overall performance and reliability of the system.

[0149] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A horizontal flywheel energy storage system, characterized by, The horizontal flywheel energy storage system comprises a flywheel energy storage unit, a connecting unit, a double-fed motor and a system control unit, the flywheel energy storage unit comprises a static part and a rotating part, and the connecting unit comprises a primary connector; The flywheel energy storage unit is rigidly or flexibly connected with the rotor of the double-fed motor through the primary connector; The stator of the double-fed motor is electrically connected with an alternating current power grid; The system control unit is electrically connected with the flywheel energy storage unit, the primary connector and the double-fed motor; The flywheel energy storage unit, the primary connector and the double-fed motor are horizontally arranged, and the flywheel energy storage unit is vacuum sealed; The static part comprises a vacuum shell, a base frame, a front bearing assembly, a rear bearing assembly, a front air seal assembly and a rear air seal assembly, and the rotating part is a flywheel rotor; the system control unit is electrically connected with the flywheel rotor; The vacuum shell is flange-connected with the front air seal assembly, the rear air seal assembly, the front bearing assembly and the rear bearing assembly to form an integral component, the integral component is installed on the base frame, and the flywheel rotor is installed in the vacuum shell; The front bearing assembly is used for supporting the front shaft diameter of the flywheel rotor, and the rear bearing assembly is used for supporting the rear shaft diameter of the flywheel rotor; The flywheel rotor is connected with the front bearing assembly in a vacuum air seal mode through the front air seal assembly, and the front air seal assembly is used for connecting the vacuum shell to the outer shell of the front bearing assembly; The flywheel rotor is connected with the rear bearing assembly in a vacuum air seal mode through the rear air seal assembly, and the rear air seal assembly is used for connecting the vacuum shell to the outer shell of the rear bearing assembly; The horizontal flywheel energy storage system further comprises a vacuum unit and a vacuum detector, the system control unit is electrically connected with the vacuum unit and the vacuum detector, the vacuum detector is used for detecting the vacuum in the flywheel energy storage unit, and the vacuum unit is connected with the flywheel energy storage unit and used for extracting vacuum in the flywheel energy storage unit; The front bearing assembly, the front air seal assembly, the vacuum shell, the rear air seal assembly and the rear bearing assembly are cooperatively structured to enhance the anti-deformation capacity of the vacuum shell under the action of atmospheric pressure; The front bearing assembly, the rear bearing assembly and the vacuum shell are all installed on the base frame; The flywheel energy storage unit further comprises a front bearing seat guide sliding block and a vacuum shell guide sliding block, the front bearing seat guide sliding block is installed between the base frame and the front bearing assembly, and the vacuum shell guide sliding block is installed between the base frame and the vacuum shell; The flywheel rotor, the vacuum shell, the front air seal assembly, the rear air seal assembly, the front bearing assembly and the rear bearing assembly are coaxially arranged.

2. The horizontal flywheel energy storage system of claim 1, wherein, The connecting unit further comprises a secondary connector, and the system control unit is electrically connected with the secondary connector; The secondary connector is connected between the flywheel energy storage unit and the primary connector; The secondary connector adopts a permanent magnet stepless speed changer or a gear speed changer.

3. The horizontal flywheel energy storage system of claim 1, wherein, The primary connector adopts a shaft coupling.

4. The horizontal flywheel energy storage system of claim 1, wherein, The horizontal flywheel energy storage system further comprises a lubrication and cooling unit, a first pipe assembly and a second pipe assembly, the system control unit is electrically connected with the lubrication and cooling unit; The lubrication and cooling unit is connected with the front bearing assembly through the first pipe assembly, so as to provide lubrication and cooling medium for the front bearing assembly; The lubrication and cooling unit is connected with the rear bearing assembly through the second pipe assembly, so as to provide lubrication and cooling medium for the rear bearing assembly.

5. The horizontal flywheel energy storage system of claim 4, wherein, The horizontal flywheel energy storage system further comprises a high-pressure top shaft unit, a third pipe assembly and a fourth pipe assembly, the system control unit is electrically connected with the high-pressure top shaft unit; The high-pressure top shaft unit is communicated with the shell of the front bearing assembly through the third pipe assembly, so as to provide high-pressure top shaft oil for the front bearing assembly, the oil medium provided by the high-pressure top shaft unit for the front bearing assembly is used to lift the front shaft diameter of the flywheel rotor at a first pressure, and the lubrication and cooling unit provides oil medium at a second pressure for the front bearing assembly; The high-pressure top shaft unit is communicated with the shell of the rear bearing assembly through the fourth pipe assembly, so as to provide oil medium at a first pressure for the rear bearing assembly, the oil medium provided by the high-pressure top shaft unit for the rear bearing assembly is used to lift the rear shaft diameter of the flywheel rotor at a first pressure, and the lubrication and cooling unit provides oil medium at a second pressure for the rear bearing assembly; Wherein, the first pressure is greater than the second pressure.

6. The horizontal flywheel energy storage system of claim 1, wherein, The base frame, the flywheel rotor, the vacuum shell, the front bearing assembly, the rear bearing assembly, the front gas seal assembly and the rear gas seal assembly are pre-assembled and integrally transported.

7. A system control method characterized by comprising: The method is suitable for the horizontal flywheel energy storage system of any one of claims 1 to 6, and the method comprises: Obtaining the working mode of the horizontal flywheel energy storage system; If the working mode is standby mode, obtaining the frequency deviation value between the grid instantaneous frequency of the alternating current power grid and the preset grid rated frequency; If the frequency deviation value is greater than 0, controlling the double-fed motor of the horizontal flywheel energy storage system to make the flywheel energy storage unit of the horizontal flywheel energy storage system store energy; If the frequency deviation value is not equal to 0, controlling the double-fed motor of the horizontal flywheel energy storage system to make the flywheel energy storage unit of the horizontal flywheel energy storage system provide inertia support for the alternating current power grid; The method further comprises: Obtaining the actual energy storage ratio of the flywheel energy storage unit of the horizontal flywheel energy storage system; If the actual energy storage ratio is within the preset ratio range, determining the working mode of the horizontal flywheel energy storage system as the standby mode; If the actual energy storage ratio is outside the preset ratio range, determining the working mode of the horizontal flywheel energy storage system as the preparation mode; If the working mode is the preparation mode, controlling the double-fed motor of the horizontal flywheel energy storage system to make the flywheel energy storage unit of the horizontal flywheel energy storage system store energy; If the working mode is the preparation mode, the step of controlling the double-fed motor of the horizontal flywheel energy storage system to enable the flywheel energy storage unit of the horizontal flywheel energy storage system to store energy comprises: If the working mode is the preparation mode, the step of controlling the double-fed motor of the horizontal flywheel energy storage system to enable the flywheel energy storage unit of the horizontal flywheel energy storage system to store energy comprises: The preset proportion range is a storage energy proportion interval enabling the horizontal flywheel energy storage system to stably provide inertia support.

8. The system control method according to claim 7, wherein The method further comprises: acquiring vacuum detection data of the flywheel energy storage unit of the horizontal flywheel energy storage system; judging whether the vacuum detection data is within a shutdown threshold range, and if so, controlling the horizontal flywheel energy storage system to shut down; judging whether the vacuum detection data is within an abnormal vacuum data range, and if so, controlling the vacuum unit of the horizontal flywheel energy storage system to extract vacuum from the flywheel energy storage unit according to the vacuum detection data.

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