Horizontal flywheel energy storage system and system control method

Abstract

The invention relates to the technical field of power grids, and discloses a horizontal flywheel energy storage system and a system control method, and the system comprises a flywheel energy storage unit, a first-stage 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 doubly-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-feed 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 adopts vacuum sealing. The flywheel energy storage unit, the first-stage connector and the double-fed motor are all arranged in a horizontal mode, a larger and heavier flywheel rotor can be supported, the rotational inertia of the flywheel rotor is increased, and then the capacity of the horizontal flywheel energy storage system for providing the rotational inertia for an alternating current power grid is improved.

Description

Technical Field

[0001] The present 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 Art

[0002] With the advancement of energy transformation, the proportion of new energy in the AC power grid continues to rise. However, the power electronic devices widely used in new energy technologies have inherent defects in accessing the power grid. Due to their static characteristics, they lack rotating structures and rotational inertia similar to synchronous machines, making it difficult to actively provide the voltage, frequency support and damping required by the AC power grid. In particular, with the increase in the penetration rate of distributed energy, the rotational inertia of the AC power grid continues to decrease, the risk of frequency deviation increases when the load or power source changes suddenly, and the unbalanced power shock of the system increases, which brings huge pressure on the safe and stable operation of the power system. In this context, in order to alleviate the pressure of AC power grid operation and new energy consumption, there is an urgent need for energy storage systems with the ability to support dynamic adjustment of the power grid to improve the efficiency of new energy acceptance of the AC power grid. Therefore, a vertical flywheel energy storage unit is developed. However, the vertical flywheel energy storage unit is supported by only one bearing, and the flywheel weight that can be borne is limited, resulting in insufficient rotational inertia. Summary of the invention

[0003] In view of this, the present application provides a horizontal flywheel energy storage system and a system control method, which are used to solve the technical problem in the prior art that the vertical flywheel energy storage unit is supported by only one bearing, can only withstand a limited flywheel weight, and leads to insufficient rotational inertia.

[0004] In the first aspect, the present application proposes a horizontal flywheel energy storage system, the horizontal flywheel energy storage system comprising: a flywheel energy storage unit, a connection unit, a doubly-fed generator and a system control unit, the flywheel energy storage unit comprising a stationary component and a rotating component, the connection unit comprising a primary connector; The flywheel energy storage unit is rigidly or flexibly connected to the rotor of the doubly-fed generator through the primary connector; The stator of the doubly-fed generator is electrically connected to an AC power grid; The system control unit is electrically connected to the flywheel energy storage unit, the primary connector and the doubly-fed generator; Wherein, the flywheel energy storage unit, the first-stage connector and the doubly-fed generator are all arranged horizontally, and the flywheel energy storage unit is vacuum sealed.

[0005] Further, the connection unit further comprises: a secondary connector, the system control unit being electrically connected to the secondary connector; The secondary connector is connected between the flywheel energy storage unit and the primary connector; Wherein, the secondary connector adopts a permanent magnet continuously variable transmission or a gear transmission.

[0006] Furthermore, the primary connector adopts a coupling or a magnetic coupling.

[0007] Further, the stationary component includes: a vacuum housing, 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 component is a flywheel rotor; the system control unit is electrically connected to the flywheel rotor; The vacuum housing is flange-connected with the front gas seal assembly, the rear gas seal assembly, the front bearing assembly, and the rear bearing assembly to form an integral component, the integral component is mounted on the base frame, and the flywheel rotor is mounted in the vacuum housing; 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; The flywheel rotor is connected to the front bearing assembly in 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; The flywheel rotor is connected to the rear bearing assembly in a vacuum-sealed manner via the rear air seal assembly, and the rear air seal assembly is used to connect the vacuum housing to the outer shell of the rear bearing assembly.

[0008] Furthermore, the front bearing assembly, the rear bearing assembly and the vacuum housing are all mounted on the base frame.

[0009] Furthermore, the flywheel energy storage unit also includes: a front bearing seat guide slider and a vacuum shell guide slider, the front bearing seat guide slider is installed between the base frame and the front bearing assembly, and the vacuum shell guide slider is installed between the base frame and the vacuum shell.

[0010] Furthermore, the flywheel rotor, the vacuum housing, the front air seal assembly, the rear air seal assembly, the front bearing assembly and the rear bearing assembly are coaxially arranged.

[0011] Furthermore, the horizontal flywheel energy storage system further comprises: a lubrication and cooling unit, a first pipeline assembly and a second pipeline assembly, and the system control unit is electrically connected to the lubrication and cooling unit; The lubrication and cooling unit is connected to the front bearing assembly through the first pipe assembly to provide lubrication and cooling medium to the front bearing assembly; The lubrication and cooling unit is connected to the rear bearing assembly through the second pipe assembly to provide lubrication and cooling medium to the rear bearing assembly.

[0012] Furthermore, the horizontal flywheel energy storage system further comprises: 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; 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 jack up the front shaft of the flywheel rotor at a first pressure, and the lubrication and cooling unit provides the oily medium at a second pressure to the front bearing assembly; The high-pressure jacking shaft unit is connected to the housing of the rear bearing assembly through the fourth pipeline assembly to provide the rear bearing assembly with an oily medium of a first pressure. The oily medium provided by the high-pressure jacking shaft unit to the rear bearing assembly is used to jack up the rear shaft of the flywheel rotor at the first pressure. The lubrication and cooling unit provides the rear bearing assembly with an oily medium of a second pressure. Wherein, the first pressure is greater than the second pressure.

[0013] Furthermore, the base frame, the flywheel rotor, the vacuum housing, the front bearing assembly, the rear bearing assembly, the front air seal assembly and the rear air seal assembly are pre-assembled and then transported as a whole.

[0014] 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 in the flywheel energy storage unit; the vacuum unit is connected to the flywheel energy storage unit to draw vacuum from the flywheel energy storage unit.

[0015] In a second aspect, the present application proposes a system control method, which is applicable to the horizontal flywheel energy storage system according to any one of the first aspects, and the method comprises: Obtaining the working mode of the horizontal flywheel energy storage system; If the working mode is the standby mode, a frequency deviation value between the instantaneous frequency of the AC power grid and a preset rated frequency of the power grid is obtained; If the frequency deviation value is greater than 0, the double-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 stores energy; If the frequency deviation value is not equal to 0, the double-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 performs inertia support on the AC power grid.

[0016] Implementing the embodiments of the present application will have the following beneficial effects: The horizontal flywheel energy storage system of the present application includes: a flywheel energy storage unit, a first-level 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 first-level 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 first-level connector and the doubly-fed motor; wherein the flywheel energy storage unit, the first-level connector and the doubly-fed motor are all horizontally arranged, and the flywheel energy storage unit is vacuum sealed. Compared with the vertical flywheel energy storage unit, in the present application, the flywheel energy storage unit, the first-level connector and the doubly-fed motor are all horizontally arranged, which can support a larger and heavier flywheel rotor, increase the moment of inertia of the flywheel rotor, and thus improve the ability of the horizontal flywheel energy storage system to provide moment of inertia to the AC power grid. Moreover, the flywheel energy storage unit adopts vacuum sealing to reduce the air resistance of the flywheel rotor of the flywheel energy storage unit, improve the energy conversion efficiency, avoid the energy loss caused by air friction, extend the service life of the flywheel energy storage unit, avoid erosion by external air, and reduce the occurrence of rust and oxidation of the flywheel rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] in: Figure 1 is a structural block diagram of a horizontal flywheel energy storage system in one embodiment; Figure 2 This is a schematic diagram of the structure of the horizontal flywheel energy storage system of the present application; Figure 3 This is a structural schematic diagram of the horizontal flywheel energy storage system of the present application from another angle; Figure 4 A flow chart of the system control method of the present application; Figure 5 Another schematic diagram of the system control method of the present application; Figure 6 Another flowchart of the system control method of the present application is shown in FIG. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0020] See also Figures 1 to 3 In one embodiment, the present application proposes a horizontal flywheel energy storage system, the horizontal flywheel energy storage system comprising: a flywheel energy storage unit 1, a connection unit 2, a doubly-fed generator 3 and a system control unit, the flywheel energy storage unit 1 comprising a stationary component and a rotating component, the connection unit 2 comprising a primary connector; The flywheel energy storage unit 1 is rigidly or flexibly connected to the rotor of the doubly-fed generator 3 via the primary connector; The stator of the doubly-fed generator 3 is electrically connected to the AC power grid 8; The system control unit is electrically connected to the flywheel energy storage unit 1, the primary connector and the doubly-fed generator 3; The flywheel energy storage unit 1 , the primary connector and the doubly-fed generator 3 are all arranged horizontally, and the flywheel energy storage unit 1 is vacuum sealed.

[0021] Compared with the vertical flywheel energy storage unit 1, in the present application, the flywheel energy storage unit 1, the first-stage connector and the double-fed generator 3 are all arranged horizontally, which can support a larger and heavier flywheel rotor 11, so that the moment of inertia of the flywheel rotor 11 can be increased, thereby improving the ability of the horizontal flywheel energy storage system to provide moment of inertia to the AC power grid. In addition, the flywheel energy storage unit 1 adopts vacuum sealing to reduce the air resistance of the flywheel rotor 11 of the flywheel energy storage unit 1, improve the energy conversion efficiency, and avoid the energy loss caused by air friction, extend the service life of the flywheel energy storage unit 1, and is not corroded by the outside air, reducing the rust and oxidation of the flywheel rotor 11.

[0022] The flywheel energy storage unit 1, the primary connector and the doubly-fed generator 3 are all arranged horizontally, and the axis of the flywheel energy storage unit 1, the axis of the primary connector and the axis of the doubly-fed generator 3 are not perpendicular to the ground.

[0023] The double-fed machine 3 is both a double-fed motor without load and a double-fed generator without a prime mover. The double-fed machine 3 has the functions of energy storage, power generation and phase adjustment.

[0024] The system control unit includes: a general control subunit, a flywheel control subunit, a motor control subunit 41 and a connection control subunit. The general control subunit is used to control the operation of the flywheel control subunit, the motor control subunit 41 and the connection control subunit. The flywheel control subunit is used to control the operation of the flywheel energy storage unit 1. The connection control subunit is used to control the operation of the primary connector. The motor control subunit 41 is used to control the operation of the double-fed generator 3.

[0025] The motor control subunit 41 can be selected from the prior art and will not be described in detail here.

[0026] Optionally, the overall control subunit, the flywheel control subunit, the motor control subunit 41 and the connection control subunit can all constitute independent structures (for example, by making them into independent chips and installing the chips in computer equipment or industrial computers). The chip is obviously a type of hardware, and the chips belonging to the hardware type are installed in computer equipment or industrial computers of the hardware type.

[0027] See also 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 .

[0028] The motor control subunit 41 is used to detect and receive signals, and control the double-fed motor 3 and the AC power grid 8 to transfer inertia and energy to each other.

[0029] The working principle of the horizontal flywheel energy storage system is as follows: when the instantaneous grid frequency of the AC grid 8 is greater than the preset grid rated frequency, the doubly fed motor 3 draws electric energy from the AC grid 8 to increase the rotation 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 grid frequency of the AC grid 8 is not equal to the preset grid rated frequency, the doubly fed motor 3 of the horizontal flywheel energy storage system is controlled to reduce the rotation speed of the flywheel rotor 11 of the flywheel energy storage unit 1, thereby achieving inertial support for the AC grid 8.

[0030] The flywheel energy storage unit 1 is a unit that uses flywheel energy storage technology to store and release energy.

[0031] Flywheel energy storage technology is a type of energy storage technology that stores energy in the form of kinetic energy. It achieves energy storage / release by accelerating / decelerating the rotor through the motor / generator. The main advantages of flywheel energy storage are fast climbing ability, high energy conversion efficiency and long service life. It has unique advantages in providing auxiliary services such as inertia and frequency regulation. Flywheels have no geographical restrictions and can be easily installed, which makes them popularizable and replicable on a large scale.

[0032] In one embodiment, the connection unit 2 further includes: a secondary connector, the system control unit being electrically connected to the secondary connector; The secondary connector is connected between the flywheel energy storage unit 1 and the primary connector; Among them, the secondary connector adopts a permanent magnet continuously variable transmission or a gear transmission. By adopting a permanent magnet continuously variable transmission or a gear transmission in the secondary connector, the different ratios of the speed of the flywheel rotor 11 and the speed of the doubly fed motor 3 can be adjusted, so that the proportional adjustment between the speed of the flywheel rotor 11 and the speed of the doubly fed motor 3 has higher flexibility and accuracy. In this way, it can better adapt to different working scenarios and needs and optimize the operating state of the system. Secondly, it can achieve more precise speed matching and control, improve the efficiency and performance of the entire system, and ensure that the transmission and conversion of energy are more efficient and stable. Furthermore, this adjustable proportional relationship provides more possibilities for the operation and optimization of the system, helps to improve the adaptability and reliability of the system, and expand its scope of application and applicable environment.

[0033] In one embodiment, the primary connector adopts a coupling or a magnetic coupling. The advantages of the coupling include: it can firmly connect the two shafts and transmit torque; it can compensate for the coaxiality, angular deviation, etc. of the shaft to a certain extent; it can be used for many different types of equipment and working conditions. The advantages of the magnetic coupling include: it reduces wear and mechanical failure, and has low maintenance costs; it can effectively isolate the vibration transmission between the driving shaft and the driven shaft; it can automatically slip when the load is too large to play a protective role; silent operation: less noise during operation; it has good adaptability to harsh working environments. The primary connector adopts a coupling or a magnetic coupling, which improves the stability and reliability of the positive system.

[0034] 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, and the rotating component is a flywheel rotor 11; the system control unit is electrically connected to the flywheel rotor 11; The vacuum housing 12 is flange-connected with 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 in the vacuum housing 12; 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; The flywheel rotor 11 is connected to the front bearing assembly 14 in a vacuum-tight manner through 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; The flywheel rotor 11 is connected to the rear bearing assembly 15 in a vacuum-tight manner through the rear air seal assembly 17 . The rear air seal assembly 17 is used to connect the vacuum housing 12 to the outer shell of the rear bearing assembly 15 .

[0035] This embodiment uses 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 steadily, reducing friction and resistance during rotation, and improving energy conversion efficiency; secondly, it helps to reduce wear and energy loss and extend the service life of the equipment; thirdly, this support method can enhance the reliability and stability of the entire system operation and ensure the performance of the flywheel energy storage device at work. The flywheel rotor 11 is connected to the front bearing assembly 14 through the front air seal assembly 16 to achieve a vacuum seal connection. The front air seal assembly 16 is used to connect the vacuum shell 12 to the shell of the front bearing assembly 14. The flywheel rotor 11 is connected to the rear bearing assembly 15 through the rear air seal assembly 17 to achieve a vacuum seal connection. The rear air seal assembly 17 is used to connect the vacuum shell 12 to the shell of the rear bearing assembly 15, so as to pull the vacuum shell 12. When the vacuum shell 12 is subjected to atmospheric pressure, the deformation of the vacuum shell 12 is significantly reduced, thereby improving the air pressure resistance of the vacuum shell 12. The vacuum housing 12 increases the vacuum space for the flywheel rotor 11 and reduces the windage loss of the flywheel rotor 11 .

[0036] The front bearing assembly 14 adopts any one of a sliding bearing, an air bearing, and a magnetic bearing.

[0037] The rear bearing assembly 15 adopts any one of a sliding bearing, an air bearing, and a magnetic bearing.

[0038] Sliding bearings are bearings that work under sliding friction. Air bearings are bearings that use gas pressure to suspend the shaft. Magnetic bearings, also known as electromagnetic suspension bearings or magnetic bearings, are a new type of high-performance bearing that uses magnetic force to suspend the rotor in the air.

[0039] Both the front air seal assembly 16 and the rear air seal assembly 17 adopt air seal assemblies.

[0040] A receiving chamber is provided inside the vacuum housing 12 . The receiving chamber is a vacuum space, and the flywheel rotor 11 is located in the receiving chamber.

[0041] Optionally, the vacuum housing 12 is divided into an upper housing and a lower housing, which are combined to form a complete housing.

[0042] Optionally, the stationary component includes: a shell bracket 13 , the shell bracket 13 is mounted on the base frame 18 , the shell bracket 13 is located between the front bearing assembly 14 and the rear bearing assembly 15 , and the vacuum shell 12 is mounted on the shell bracket 13 .

[0043] The housing support 13 guides the vacuum housing 12 to expand radially to both sides when the vacuum housing 12 expands due to heat, so as to keep the housing coaxial with the flywheel rotor 11 .

[0044] The shapes and structures of the vacuum housing 12 and the housing support 13 can be set according to requirements, and will not be described in detail here.

[0045] A gas seal assembly is a device assembly used to seal gas. It is usually used in some equipment or systems that need to control gas leakage or ensure a specific gas environment. The specific structure and design of the gas seal assembly will vary depending on the application scenario. Its function is to prevent abnormal leakage of gas in certain parts and maintain the normal operation of the system and a specific gas state. The gas seal assembly may include seals, gaskets, sealing rings and other components.

[0046] The vertical flywheel energy storage unit 1 uses a rubber ring seal for its rotational seal, which has large contact friction loss and is prone to heat damage. In order to solve this problem, the flywheel energy storage unit 1, the first-stage connector and the doubly-fed generator 3 of the present application are all arranged horizontally, and the vacuum seal of the present application can also avoid the problems caused by the use of a rubber ring seal for the rotational seal of the vertical flywheel energy storage unit 1 while being able to support a larger and heavier flywheel rotor 11.

[0047] The front bearing assembly 14 and the rear bearing assembly 15 both adopt sliding bearing assemblies. The sliding bearing assembly is an assembly that can provide the common functions of a sliding bearing. The sliding bearing assembly can be selected from the prior art according to the requirements, and will not be described in detail here.

[0048] Sliding bearings are bearings that work under sliding friction. Sliding bearings work smoothly, reliably and without noise. Under liquid lubrication conditions, the sliding surfaces are separated by lubricating oil without direct contact, which can greatly reduce friction loss and surface wear. The oil film also has a certain vibration absorption capacity. However, the starting friction resistance is relatively large.

[0049] 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 part.

[0050] The shape and structure of the base frame 18 can be set according to requirements and will not be described in detail here.

[0051] Optionally, the doubly-fed generator 3 is mounted on the base frame 18 .

[0052] The base frame 18 is installed on the ground, and the front bearing assembly 14 , the rear bearing assembly 15 and the vacuum housing 12 are all installed on a side of the base frame 18 away from the ground.

[0053] Optionally, the flywheel energy storage unit 1 also includes: a first inclined washer, a second inclined washer, and a third inclined washer, the first inclined washer is arranged between the front bearing assembly 14 and the ground, the second inclined washer is arranged between the rear bearing assembly 15 and the ground, and the third inclined washer is arranged between the doubly fed motor 3 and the ground.

[0054] Optionally, the first inclined washer, the second inclined washer, and the third inclined washer are located between the base frame 18 and the ground.

[0055] In one embodiment, the flywheel energy storage unit 1 further includes: a front bearing seat guide slider and a vacuum housing guide slider, wherein the front bearing seat 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 seat guide slider and the vacuum housing guide slider allow the flywheel rotor 11 and the vacuum housing 12 to expand or contract axially when they expand or contract with heat or cold.

[0056] The front bearing seat guide slider and the vacuum housing guide slider both use guide sliders. The guide slider can be selected from the existing technology according to the needs, and will not be described in detail here.

[0057] 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. The coaxial arrangement can ensure that the flywheel rotor 11 and other components maintain a high degree of concentricity during rotation, reduce eccentricity and vibration, and improve the accuracy and stability of operation. Such a design can not only adapt to temperature changes, reduce stress concentration, maintain structural integrity and improve reliability, but also improve operation accuracy, optimize power transmission, enhance structural integrity, reduce wear and facilitate installation and maintenance.

[0058] 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, that is, the rotating axis of the flywheel rotor 11, the central axis of the vacuum housing 12, the rotating axis of the front bearing assembly 14 and the rotating axis of the rear bearing assembly 15, and the rotating axis of the flywheel rotor 11, the central axis of the vacuum housing 12, the rotating axis of the front bearing assembly 14 and the rotating axis of the rear bearing assembly 15 are located on the same straight line.

[0059] In one embodiment, the horizontal flywheel energy storage system further includes: a lubrication and cooling unit 10, a first pipeline assembly and a second pipeline assembly, and the system control unit is electrically connected to the lubrication and cooling unit 10; 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; The lubricating and cooling unit 10 is connected to the rear bearing assembly 15 through the second pipe assembly to provide lubricating and cooling medium to the rear bearing assembly 15. The lubricating and cooling medium plays an important role in that it can significantly reduce the friction loss caused by the mutual movement between components, making the equipment run more smoothly and efficiently; at the same time, it also has an excellent cooling effect, and can take away the heat generated by friction in time, avoiding the adverse effects of excessive temperature on the equipment, effectively maintaining the equipment to work stably within a suitable temperature range, extending the service life of the equipment, and ensuring the reliable operation of the entire system.

[0060] The lubricating cooling medium may be oil.

[0061] The first pipeline assembly includes an oil inlet pipe and an oil outlet pipe; the oil inlet pipe is connected between the lubricating and cooling unit 10 and the front bearing assembly 14 to input lubricating and cooling medium to the front bearing assembly 14; the oil outlet pipe is connected between the lubricating and cooling unit 10 and the front bearing assembly 14 to transport the lubricating and cooling medium in the front bearing assembly 14 back to the lubricating and cooling unit 10. Thus, the front bearing assembly 14 is provided with flowing lubricating and cooling medium.

[0062] The second pipeline assembly includes an oil inlet pipe and an oil outlet pipe; the oil inlet pipe is connected between the lubricating and cooling unit 10 and the rear bearing assembly 15 to input lubricating and cooling medium to the rear bearing assembly 15; the oil outlet pipe is connected between the lubricating and cooling unit 10 and the rear bearing assembly 15 to transport the lubricating and cooling medium in the rear bearing assembly 15 back to the lubricating and cooling unit 10. Thus, the rear bearing assembly 15 is provided with flowing lubricating and cooling medium.

[0063] The lubricating and cooling unit 10 comprises: 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.

[0064] In one embodiment, the horizontal flywheel energy storage system further comprises: 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; 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 jack up the front shaft of the flywheel rotor 11 at a first pressure, and the lubrication cooling unit 10 provides the front bearing assembly 14 with an oily medium at a second pressure; The high-pressure jacking shaft unit is connected to the housing of the rear bearing assembly 15 through the fourth pipeline assembly to provide the rear bearing assembly 15 with an oily medium of a first pressure. The oily medium provided by the high-pressure jacking shaft unit to the rear bearing assembly 15 is used to jack up the rear shaft of the flywheel rotor 11 at the first pressure. The lubrication cooling unit 10 provides the rear bearing assembly 15 with an oily medium of a second pressure. The first pressure is greater than the second pressure. The oil medium of the first pressure is provided to the front bearing assembly 14, and the oil medium of the first pressure is provided to the rear bearing assembly 15 to lift the shaft of the flywheel rotor 11 and reduce friction.

[0065] Optionally, the third pipeline assembly includes an oil inlet pipe, in which case the third pipeline assembly and the first pipeline assembly share an oil outlet pipe.

[0066] Optionally, the third pipeline assembly includes an oil inlet pipe and an oil outlet pipe, and in this case, the oil outlet pipe of the third pipeline assembly is independently arranged from the oil outlet pipe of the first pipeline assembly.

[0067] Optionally, the fourth pipeline assembly includes an oil inlet pipe and an oil outlet pipe, and in this case the oil outlet pipe of the second pipeline assembly and the fourth pipeline assembly share the oil outlet pipe and are independently arranged.

[0068] The high-pressure top shaft 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 pipe of the third pipeline assembly and the oil inlet pipe of the fourth pipeline assembly.

[0069] In another embodiment of the present embodiment, the high-pressure jacking unit adopts a pressurizer 111; the lubricating and cooling unit 10 is connected to the housing of the front bearing assembly 14 through the third pipe assembly to provide the front bearing assembly 14 with an oily medium of a first pressure; the lubricating and cooling unit 10 is connected to the housing of the rear bearing assembly 15 through the fourth pipe assembly to provide the oily medium of a third pressure to the rear bearing assembly 15. The pressurizer 111 increases the pressure on the oil inlet pipe of the third pipe assembly, and the pressurizer 111 increases the pressure on the oil inlet pipe of the fourth pipe assembly.

[0070] 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 gas seal assembly 16 and the rear gas seal assembly 17 are pre-assembled and transported as a whole. By pre-assembling and transporting as a whole, the construction problem of the equipment installation site is solved and the efficiency is greatly improved.

[0071] 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 in the flywheel energy storage unit 1; the vacuum unit 19 is connected to the flywheel energy storage unit 1 to extract a vacuum from the flywheel energy storage unit 1. Extracting a vacuum from the flywheel energy storage unit 1 by the vacuum unit 19 provides a basis for the flywheel energy storage unit 1 to adopt a vacuum seal.

[0072] The vacuum unit 19 may be a vacuum pump, which is used to extract air from the accommodating cavity of the vacuum housing 12, so that the accommodating cavity of the vacuum housing 12 enters and maintains a vacuum. The vacuum detector is installed on the inner wall of the accommodating cavity of the vacuum housing 12, and is used to detect vacuum data in the accommodating cavity, and the detected data is used as vacuum detection data.

[0073] See also Figure 4 In one embodiment, the present application proposes a system control method, which is applicable to any of the above-mentioned horizontal flywheel energy storage systems, and the method includes: S1: Obtaining the working mode of the horizontal flywheel energy storage system; Optionally, the operating mode of the horizontal flywheel energy storage system can be obtained from a preset storage space.

[0074] The working mode of the horizontal flywheel energy storage system is a standby mode or a preparation mode.

[0075] It is understandable that, in the preparation mode, the horizontal flywheel energy storage system cannot provide inertia support for the AC power grid 8 .

[0076] S2: If the working mode is the standby mode, a frequency deviation value between the instantaneous frequency of the AC power grid 8 and a preset rated frequency of the power grid is obtained; Specifically, if the working mode is the standby mode, it means that the pre-stored energy of the flywheel energy storage unit 1 has met the requirement of 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.

[0077] The instantaneous frequency of the power grid is the AC power supply frequency of the AC power grid 8 detected in real time.

[0078] The preset grid rated frequency is the rated AC power supply frequency of the AC grid 8. Optionally, the preset grid rated frequency is 50 Hz.

[0079] Specifically, the preset rated frequency of the power grid is subtracted from the instantaneous frequency of the power grid, and the data obtained by the subtraction is used as the frequency deviation value.

[0080] S3: If the frequency deviation value is greater than 0, the double-fed generator 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; Specifically, if the frequency deviation value is greater than 0, it indicates that the active power of the AC power grid 8 is in excess, 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 to increase the rotation speed of the flywheel rotor 11 of the flywheel energy storage unit 1 of the horizontal flywheel energy storage system, energy is stored in the flywheel energy storage unit 1.

[0081] S4: If the frequency deviation value is not equal to 0, the double-fed generator 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 performs inertial support on the AC power grid 8.

[0082] Specifically, if the frequency deviation value is not equal to 0, it means that the instantaneous frequency of the AC power grid 8 at this time does not meet the preset requirements (the preset grid rated frequency), and the AC power grid 8 needs to be frequency-modulated. By controlling the double-fed motor 3 of the horizontal flywheel energy storage system, the speed of the flywheel rotor 11 of the flywheel energy storage unit 1 of the horizontal flywheel energy storage system is reduced to provide inertia support for the AC power grid 8 and realize the inertia 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 rapid decline of the AC power supply frequency of the AC power grid 8.

[0083] Compared with the vertical flywheel energy storage unit 1, in this embodiment, the flywheel energy storage unit 1, the first-stage connector and the doubly-fed generator 3 are all arranged horizontally, which can support a larger and heavier flywheel rotor 11, thereby increasing the rotational inertia of the flywheel rotor 11, thereby improving the ability of the horizontal flywheel energy storage system to provide rotational inertia to the AC power grid. Moreover, the flywheel energy storage unit 1 adopts vacuum sealing to reduce the air resistance of the flywheel rotor 11 of the flywheel energy storage unit 1, improve the energy conversion efficiency, avoid the energy loss caused by air friction, extend the service life of the flywheel energy storage unit 1, and is not corroded by the outside air, reducing the rust and oxidation of the flywheel rotor 11; when the working mode is the standby mode, the inertia support of the AC power grid 8 can be flexibly performed according to the frequency deviation value, which is helpful to maintain the frequency stability of the power grid and enhance the reliability and stability of the power grid; when the working mode is the standby mode, energy can be absorbed from the AC power grid 8 and stored in the flywheel energy storage unit 1, so as to realize the effective allocation and storage of energy, improve the energy utilization efficiency, and provide the AC power grid 8 with a certain energy reserve and adjustment capability under different working conditions, which is conducive to ensuring the continuous and stable operation of the power grid.

[0084] See also Figure 5 In one embodiment, the method further comprises: S51: Obtaining the actual energy storage ratio of the flywheel energy storage unit 1 of the horizontal flywheel energy storage system; 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.

[0085] The actual energy storage ratio is the real-time energy storage ratio of the flywheel energy storage unit 1 .

[0086] S52: if the actual energy storage ratio is within a preset ratio range, determining the working mode of the horizontal flywheel energy storage system to be the standby mode; 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 requirement of providing inertia support. Therefore, the working mode of the horizontal flywheel energy storage system is determined to be the standby mode.

[0087] S53: if the actual energy storage ratio is outside the preset ratio range, determining the working mode of the horizontal flywheel energy storage system as a preparation mode; 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 requirement of providing inertia support. Therefore, the working mode of the horizontal flywheel energy storage system is determined to be the preparation mode.

[0088] S54: If the working mode is the preparation mode, 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.

[0089] Optionally, if the working mode is the preparation mode, the doubly-fed motor 3 of the horizontal flywheel energy storage system is controlled to absorb energy from the AC power grid 8 to increase the rotation speed of the flywheel rotor 11 of the flywheel energy storage unit 1 of the horizontal flywheel energy storage system, thereby storing energy in the flywheel energy storage unit 1.

[0090] Optionally, if the working mode is the preparation mode, the doubly-fed motor 3 of the horizontal flywheel energy storage system is controlled to absorb energy from other power supplies (power supplies other than the AC power grid 8) to increase the rotation speed of the flywheel rotor 11 of the flywheel energy storage unit 1 of the horizontal flywheel energy storage system, thereby storing energy in the flywheel energy storage unit 1.

[0091] In this embodiment, if the actual energy storage ratio is within a preset ratio range, the working mode of the horizontal flywheel energy storage system is determined to be the standby mode to achieve inertia support for the AC power grid 8; if the working mode is the preparation mode, the double-fed motor 3 of the horizontal flywheel energy storage system is controlled to store energy in the flywheel energy storage unit 1 of the horizontal flywheel energy storage system, thereby achieving automatic control of the horizontal flywheel energy storage system; and if the actual energy storage ratio is within a preset ratio range, the working mode of the horizontal flywheel energy storage system is determined to be the standby mode to achieve inertia support for the AC power grid 8, thereby improving the stability of the horizontal flywheel energy storage system in providing inertia support.

[0092] See also Figure 6 In one embodiment, the method further comprises: S61: Acquire vacuum detection data of the flywheel energy storage unit 1 of the horizontal flywheel energy storage system; Specifically, vacuum detection data obtained by the vacuum detector of the horizontal flywheel energy storage system detecting the flywheel energy storage unit 1 is obtained in real time.

[0093] S62: determining whether the vacuum detection data is within a shutdown threshold range, and if so, controlling the horizontal flywheel energy storage system to shut down; Specifically, it is determined whether the vacuum detection data is within the shutdown threshold range, that is, whether shutdown is required. 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 cause an accident or equipment damage. Therefore, the horizontal flywheel energy storage system is controlled to shut down to provide a basis for maintenance.

[0094] 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 to the flywheel energy storage unit 1 according to the vacuum detection data.

[0095] Specifically, it is determined whether the vacuum detection data is within the abnormal vacuum data range, that is, it is determined 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 working requirements of the flywheel rotor 11. Therefore, a control instruction is generated according to the vacuum detection data, and the vacuum unit 19 of the horizontal flywheel energy storage system is controlled by the control instruction to draw vacuum to the flywheel energy storage unit 1.

[0096] This embodiment can achieve precise control of the horizontal flywheel energy storage system by judging the vacuum detection data. When the vacuum detection data is within the shutdown threshold range, the shutdown is controlled in time to ensure the safety and stability of the system and avoid further expansion of potential risks; and when the vacuum detection data is within the abnormal vacuum data range, the vacuum unit 19 can be accurately controlled to extract vacuum from the flywheel energy storage unit 1 according to the specific data, which is conducive to maintaining the rationality and stability of the vacuum environment in the system, ensuring that the flywheel energy storage unit 1 can operate normally under appropriate vacuum conditions, and improving the overall performance and reliability of the system.

[0097] The above disclosure is only the preferred embodiment of the present application, which certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A horizontal flywheel energy storage system, characterized in that: The horizontal flywheel energy storage system comprises: a flywheel energy storage unit, a connection unit, a doubly-fed generator and a system control unit, wherein the flywheel energy storage unit comprises a stationary component and a rotating component, and the connection unit comprises a primary connector; The flywheel energy storage unit is rigidly or flexibly connected to the rotor of the doubly-fed generator through the primary connector; The stator of the doubly-fed generator is electrically connected to an AC power grid; The system control unit is electrically connected to the flywheel energy storage unit, the primary connector and the doubly-fed generator; Wherein, the flywheel energy storage unit, the first-stage connector and the doubly-fed generator are all arranged horizontally, and the flywheel energy storage unit is vacuum sealed.

2. The horizontal flywheel energy storage system according to claim 1, characterized in that: The connection unit further comprises: a secondary connector, the system control unit being electrically connected to the secondary connector; The secondary connector is connected between the flywheel energy storage unit and the primary connector; Wherein, the secondary connector adopts a permanent magnet continuously variable transmission or a gear transmission.

3. The horizontal flywheel energy storage system according to claim 1, characterized in that: The primary connector adopts a coupling or a magnetic coupling.

4. The horizontal flywheel energy storage system according to claim 1, characterized in that: The stationary components include: a vacuum housing, a base frame, a front bearing assembly, a rear bearing assembly, a front air seal assembly and a rear air seal assembly; the rotating component is a flywheel rotor; the system control unit is electrically connected to the flywheel rotor; The vacuum housing is flange-connected with the front gas seal assembly, the rear gas seal assembly, the front bearing assembly, and the rear bearing assembly to form an integral component, the integral component is mounted on the base frame, and the flywheel rotor is mounted in the vacuum housing; 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; The flywheel rotor is connected to the front bearing assembly in 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; The flywheel rotor is connected to the rear bearing assembly in a vacuum-sealed manner via the rear air seal assembly, and the rear air seal assembly is used to connect the vacuum housing to the outer shell of the rear bearing assembly.

5. The horizontal flywheel energy storage system according to claim 4, characterized in that: The front bearing assembly, the rear bearing assembly and the vacuum housing are all mounted on the base frame.

6. The horizontal flywheel energy storage system according to claim 5, characterized in that: The flywheel energy storage unit also includes: a front bearing seat guide slider and a vacuum housing guide slider, the front bearing seat 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.

7. The horizontal flywheel energy storage system according to claim 4, characterized in that: The flywheel rotor, the vacuum housing, the front air seal assembly, the rear air seal assembly, the front bearing assembly and the rear bearing assembly are coaxially arranged.

8. The horizontal flywheel energy storage system according to claim 4, characterized in that: The horizontal flywheel energy storage system further comprises: a lubrication and cooling unit, a first pipeline assembly and a second pipeline assembly, and the system control unit is electrically connected to the lubrication and cooling unit; The lubrication and cooling unit is connected to the front bearing assembly through the first pipe assembly to provide lubrication and cooling medium to the front bearing assembly; The lubrication and cooling unit is connected to the rear bearing assembly through the second pipe assembly to provide lubrication and cooling medium to the rear bearing assembly.

9. The horizontal flywheel energy storage system according to claim 8, characterized in that: The horizontal flywheel energy storage system further comprises: 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; The high-pressure jacking shaft unit is connected to the housing of the front bearing assembly through the third pipeline assembly to provide high-pressure jacking shaft oil to the front bearing assembly. The oily medium provided by the high-pressure jacking shaft unit to the front bearing assembly is used to jack up the front shaft of the flywheel rotor at a first pressure, and the lubrication and cooling unit provides the oily medium at a second pressure to the front bearing assembly; The high-pressure jacking shaft unit is connected to the housing of the rear bearing assembly through the fourth pipeline assembly to provide the rear bearing assembly with an oily medium of a first pressure. The oily medium provided by the high-pressure jacking shaft unit to the rear bearing assembly is used to jack up the rear shaft of the flywheel rotor at the first pressure. The lubrication and cooling unit provides the rear bearing assembly with an oily medium of a second pressure. Wherein, the first pressure is greater than the second pressure.

10. The horizontal flywheel energy storage system according to claim 5, characterized in that: The base frame, the flywheel rotor, the vacuum housing, the front bearing assembly, the rear bearing assembly, the front air seal assembly, and the rear air seal assembly are pre-assembled and then transported as a whole.

11. The horizontal flywheel energy storage system according to claim 1, characterized in that: 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 in the flywheel energy storage unit; the vacuum unit is connected to the flywheel energy storage unit to extract vacuum from the flywheel energy storage unit.

12. A system control method, characterized in that: The method is applicable to the horizontal flywheel energy storage system according to any one of claims 1 to 11, and the method comprises: Obtaining the working mode of the horizontal flywheel energy storage system; If the working mode is the standby mode, a frequency deviation value between the instantaneous frequency of the AC power grid and a preset rated frequency of the power grid is obtained; If the frequency deviation value is greater than 0, the double-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 stores energy; If the frequency deviation value is not equal to 0, the double-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 performs inertia support on the AC power grid.

13. The system control method according to claim 12, characterized in that: The method further comprises: Obtaining an actual energy storage ratio of a flywheel energy storage unit of the horizontal flywheel energy storage system; If the actual energy storage ratio is within the preset ratio range, the working mode of the horizontal flywheel energy storage system is determined to be the standby mode; 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 a preparation mode; If the working mode is the preparation mode, 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 stores energy.

14. The system control method according to claim 12, characterized in that: The method further comprises: Acquiring vacuum detection data of a flywheel energy storage unit of the horizontal flywheel energy storage system; Determine whether the vacuum detection data is within a shutdown threshold range, and if so, control the horizontal flywheel energy storage system to shut down; It is determined whether the vacuum detection data is within the abnormal vacuum data range. If it is within the abnormal vacuum data range, the vacuum unit of the horizontal flywheel energy storage system is controlled to draw vacuum into the flywheel energy storage unit according to the vacuum detection data.

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