WO2023005950A1 - 飞轮储能系统 - Google Patents

飞轮储能系统 Download PDF

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Publication number
WO2023005950A1
WO2023005950A1 PCT/CN2022/108087 CN2022108087W WO2023005950A1 WO 2023005950 A1 WO2023005950 A1 WO 2023005950A1 CN 2022108087 W CN2022108087 W CN 2022108087W WO 2023005950 A1 WO2023005950 A1 WO 2023005950A1
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WIPO (PCT)
Prior art keywords
rotor
flywheel
energy storage
generator
speed
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PCT/CN2022/108087
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English (en)
French (fr)
Inventor
陈俊
白宁
孙璇
吴智泉
刘雨涵
孙册
张蔚琦
高康伟
刘腾飞
李芳菲
陈厚存
桂志远
冯晨
曾子竞
魏方舟
Original Assignee
国家电投集团科学技术研究院有限公司
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Publication of WO2023005950A1 publication Critical patent/WO2023005950A1/zh

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H02J1/14—Balancing the load in a network
    • H02J1/16—Balancing the load in a network using dynamo-electric machines coupled to flywheels
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J15/00—Systems for storing electric energy
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • H02J3/30—Arrangements for balancing of the load in a network by storage of energy using dynamo-electric machines coupled to flywheels
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/02—Additional mass for increasing inertia, e.g. flywheels
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/10—Structural association with clutches, brakes, gears, pulleys or mechanical starters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/18—Structural association of electric generators with mechanical driving motors, e.g. with turbines
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/16—Mechanical energy storage, e.g. flywheels or pressurised fluids

Definitions

  • the present disclosure relates to the technical field of energy storage, in particular to a flywheel energy storage system.
  • connection of a high proportion of power electronic devices will cause the power grid to remain at a low inertia level for a long time, increasing the unbalanced power impact of the system, which brings more and more pressure on the safe and stable operation of the power system.
  • an energy storage system with a certain ability to support the dynamic adjustment of the power grid is urgently needed to improve the ability of the power grid to efficiently accept new energy.
  • Flywheel energy storage technology is an energy storage technology that stores energy in the form of kinetic energy.
  • the energy storage/release is realized by the motor/generator driving the rotor to accelerate/decelerate.
  • the main advantages of flywheel energy storage are fast climbing ability, high energy conversion efficiency and long service life, etc. It has unique advantages in providing auxiliary services, such as inertia and frequency regulation.
  • the flywheel does not have any geographical restrictions, can be easily installed, and has the advantages of being scalable and replicable on a large scale.
  • flywheel energy storage technologies all use power electronic devices to assist the motor/generator to perform mutual conversion between kinetic energy and electric energy.
  • the system When the system needs to store electric energy, it will supply the external AC power to the motor through AC/DC, and then drive the flywheel rotor to rotate and store energy; when it needs to discharge, the power electronic device decouples the rotor inertia of the flywheel rotor , Play the role of rectification, frequency modulation and voltage stabilization to meet the power demand of the load.
  • power electronic devices do not have moment of inertia, so it is difficult to participate in grid inertia response. Therefore, flywheel energy storage technology cannot solve the problem that the proportion of total moment of inertia in the current grid is constantly decreasing due to the large-scale use of power electronic devices.
  • the present disclosure aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the present disclosure proposes a flywheel energy storage system.
  • the flywheel energy storage system includes: a motor; a flywheel rotor, the motor is connected to the flywheel rotor to drive the flywheel rotor to rotate; an asynchronous generator, the asynchronous generator includes a stator and a rotor, and the flywheel
  • the rotor is detachably connected to the rotor to drive the rotor to rotate, and the stator can be connected to the grid and input electric energy with a stable frequency into the grid.
  • the flywheel rotor of the flywheel energy storage system is connected to the asynchronous generator with the function of variable speed and constant frequency.
  • the asynchronous generator is connected to the power grid and can transmit at the same frequency as the power grid.
  • the electric motor is connected to the grid and used to draw power from the grid.
  • the flywheel energy storage system has an energy release state and an energy storage state
  • the motor In the state of energy release, the motor is on standby, the flywheel rotor releases kinetic energy to drive the asynchronous generator to generate electricity, and the asynchronous generator inputs electric energy with a stable frequency to the grid,
  • the electric motor takes power from the grid to drive the flywheel rotor to rotate, and the asynchronous generator stops inputting electric energy to the grid.
  • the asynchronous generator in the energy storage state, is idling, and/or, the transmission connection between the flywheel rotor and the rotor is disconnected.
  • the flywheel energy storage system has a standby state, and in the standby state, the electric motor is on standby and the generator is idling.
  • the asynchronous generator is a wound rotor asynchronous generator or a double-fed asynchronous generator.
  • the flywheel energy storage system further includes a speed change device, the speed change device is connected between the flywheel rotor and the asynchronous generator, the speed change device has an input end and an output end, and the flywheel rotor is connected to the asynchronous generator.
  • the input end is in transmission connection
  • the output end is in transmission connection with the rotor
  • the speed change device is used for transmitting the moment of inertia of the flywheel rotor.
  • the transmission device is a transmission device with a fixed transmission ratio, or the transmission device is a transmission device with an adjustable transmission ratio.
  • the transmission device is a gear transmission, a torque converter, a magnetic transformer or a permanent magnet transmission.
  • the rotation speed of the flywheel rotor is 100rpm-1000000rpm, and the transmission ratio of the transmission device is 0.03-333.
  • the flywheel energy storage system further includes a flywheel energy storage controller for controlling the energy input and input power of the flywheel rotor.
  • the flywheel energy storage controller includes:
  • a power grid detection module the power grid detection module is used to detect the current frequency of the power grid
  • a motor control module the motor control module is used to control the opening and closing and input and output power of the motor according to the current frequency of the power grid.
  • Fig. 1 is a schematic diagram of a flywheel energy storage system according to Embodiment 1 of the present disclosure.
  • Fig. 2 is a schematic diagram of a flywheel energy storage system according to Embodiment 2 of the present disclosure.
  • Fig. 3 is a schematic diagram of a flywheel energy storage system according to Embodiment 3 of the present disclosure.
  • Fig. 4 is a schematic diagram of a flywheel energy storage system according to Embodiment 4 of the present disclosure.
  • Fig. 5 is a schematic diagram of a flywheel energy storage system according to Embodiment 5 of the present disclosure.
  • Fig. 6 is a schematic diagram of a flywheel energy storage system according to Embodiment 6 of the present disclosure.
  • FIG. 7 is a schematic diagram of a flywheel energy storage controller according to an embodiment of the disclosure.
  • flywheel energy storage system 1 flywheel rotor 111; motor 112; asynchronous generator 20; wound rotor asynchronous generator 21; double-fed asynchronous generator 32;
  • Transmission shaft 30 first transmission shaft 31 ; second transmission shaft 32 ; fixed transmission ratio transmission device 41 ; transmission ratio adjustable device 42 ; converter 50 .
  • the flywheel energy storage system 1 includes a flywheel rotor 111 , a motor 112 and an asynchronous generator 20 .
  • the flywheel rotor 111 can realize energy storage, and deceleration of the flywheel rotor 111 can realize energy release.
  • the flywheel rotor 111 is connected with the motor 112, and the motor 112 is used to drive the flywheel rotor 111 to rotate.
  • the electric motor 112 accelerates the rotation by driving the flywheel rotor 111 , and finally realizes that electric energy is stored in the form of kinetic energy in the flywheel energy storage unit 10 .
  • the motor 112 is connected to the grid for taking power from the grid, and the motor 112 takes power from the grid to drive the flywheel rotor 111 to rotate, and the speed of the flywheel rotor 111 increases to store kinetic energy.
  • the asynchronous generator 20 includes a generator stator (not shown in the figure) and a generator rotor (not shown in the figure).
  • the generator stator is energized to generate a rotating magnetic field.
  • the flywheel rotor 111 is detachably connected to the generator rotor. The rotation of the flywheel rotor 111 can drive the generator rotor to rotate.
  • the generator rotor rotates and cuts the rotating magnetic field generated by the generator stator.
  • the stator of the generator stator generates an induced potential around the shaft. By changing the current passed into the generator rotor, the frequency of the rotating magnetic field of the generator stator is kept constant, and the stator winding of the generator stator generates a stable induced potential.
  • the stator of the generator can be connected to the grid and input electric energy with a stable frequency into the grid.
  • the asynchronous generator 20 has the function of variable speed and constant frequency, and can input constant frequency current to the grid.
  • the asynchronous generator 20 can stably input electric energy to the grid without being affected by changes in the rotational speed of the flywheel rotor 111 , even if the rotational speed of the flywheel rotor 111 changes, the asynchronous generator 20 can also stably input electric energy to the grid.
  • the rotational speed of the rotating magnetic field of the generator stator (the synchronous rotational speed of the asynchronous generator 20 and the electrical grid rotational speed) is 3000 rpm, and the generator stator can stably input current with a frequency of 50 Hz to the electrical grid.
  • the rotational speed of the rotating magnetic field of the generator stator is not the mechanical rotational speed.
  • the flywheel energy storage system 1 can be connected to the grid to participate in the grid inertia response, store the overflow energy in the flywheel rotor 111 according to the overflow ratio, or draw energy from the flywheel rotor 111 according to the missing ratio to supplement the grid, reducing grid frequency fluctuations.
  • the flywheel rotor of the flywheel energy storage system is connected to the asynchronous generator with the function of variable speed and constant frequency.
  • the asynchronous generator is connected to the power grid and can transmit at the same frequency as the power grid.
  • the speed change of the flywheel rotor will not affect the asynchronous power generation Therefore, the flywheel energy storage system provided by the embodiment of the present disclosure is connected to the grid without using power electronic devices for decoupling, rectification, frequency modulation, and voltage stabilization, which solves the problem of power electronic devices in the current grid
  • the continuous reduction of the total moment of inertia caused by use can improve the moment of inertia in the power grid, provide the necessary voltage and frequency support for the power grid, reduce the risk of large frequency deviations in the power grid, and enable the power system to operate safely and stably , and improve the ability of the grid to efficiently accept new energy.
  • the composition, connection relationship and operation process of the flywheel energy storage system 1 provided in the present disclosure will be described below by taking the schematic diagram of the flywheel energy storage system 1 shown in FIG. 1 as an example.
  • the flywheel energy storage system 1 includes a flywheel rotor 111 , a motor 112 , an asynchronous generator 20 , and a transmission shaft 30 .
  • the transmission shaft 30 runs through the flywheel rotor 111 , and one end of the transmission shaft 30 is in transmission connection with the output end of the motor 112 , and the other end of the transmission shaft 30 is in transmission connection with the generator rotor of the asynchronous generator 20 .
  • the electric motor 112 is connected with the flywheel rotor 111 , and the electric motor 112 can drive the speed of the flywheel rotor 111 to increase through the transmission shaft 30 to store kinetic energy.
  • the flywheel rotor 111 can drive the generator rotor of the asynchronous generator 20 to rotate through the transmission shaft 30 .
  • the generator stator of the asynchronous generator 20 is connected to the grid through a transformer (not shown in the figure) to supply power to the grid.
  • the mechanical speed of the generator rotor of the asynchronous generator 20, the speed of the transmission shaft 30 and the output speed of the flywheel rotor 111 are equal, and the magnetic field speed of the generator stator of the asynchronous generator 20 is constant at 3000rpm.
  • the output frequency of the asynchronous generator 20 is stable at 50Hz.
  • the rotational speed of the flywheel rotor 111 is constantly changing, causing the mechanical rotational speed of the generator rotor to change continuously. Therefore, in many cases, the mechanical rotational speed of the generator rotor is different from the magnetic field rotational speed of the generator stator. is asynchronous. To keep the magnetic field speed of the generator stator constant and make it transmit electricity at a constant frequency, it can be realized by changing the current passed into the generator rotor.
  • the domestic power grid frequency reference line is 50Hz
  • the magnetic field speed of the generator stator can be kept constant at 3000rpm.
  • the foreign power grid frequency reference line is 60Hz
  • the magnetic field speed of the generator stator can be kept constant at 3600rpm, that is, the magnetic field speed of the generator stator can be adjusted according to the frequency reference of the power grid.
  • the current frequency of the generator rotor is changed, or the power generation is changed according to the slip ratio of the asynchronous generator 20
  • the magnetic field speed r0 (grid speed) of the generator stator the mechanical speed r1 of the generator rotor (the speed of the flywheel rotor 111)+the magnetic field speed r2 matched by the generator rotor current, if the magnetic field speed r0 (grid speed) of the generator stator is maintained ) is 3000rpm, then:
  • the magnetic field speed r2 matched with the rotor current of the generator is not a mechanical speed.
  • the mechanical speed generated by the rotation of the generator rotor and the magnetic field speed generated by the generator rotor current are superimposed to reach the magnetic field speed of the generator stator, that is, the speed of the grid, so that the magnetic field speed of the generator stator is not changed by the speed of the flywheel rotor 111 and always keep constant, so that the asynchronous generator 20 can transmit power to the power grid at a constant frequency to realize asynchronous power generation.
  • the asynchronous generator 20 can generate electricity stably.
  • the asynchronous generator 20 is a wound rotor asynchronous generator or a double-fed asynchronous generator.
  • the flywheel energy storage system 1 has an energy storage state and an energy release state, and can switch between the energy storage state and the energy release state. It can also be said that the flywheel energy storage system 1 includes an energy storage stage and an energy release stage during operation, the energy storage stage corresponds to the above energy storage state, and the energy release stage corresponds to the above energy release state.
  • the flywheel energy storage system 1 converts electrical energy into kinetic energy for storage; when the flywheel energy storage system 1 is in the energy release state, it releases the stored kinetic energy and converts the kinetic energy into electrical energy for output.
  • the electric motor 112 operates to obtain power from the grid and drives the flywheel rotor 111 to rotate through the transmission shaft 30 , the speed of the flywheel rotor 111 increases to realize energy storage, and in this state the asynchronous generator 20 stops inputting electric energy to the grid.
  • the flywheel rotor 111 is driven by the motor 112 to increase its speed to a rated maximum speed.
  • the flywheel rotor 111 completes energy storage, and then the motor 112 stops driving the flywheel rotor 111 .
  • the rated maximum rotational speed is 100rpm-1000000rpm.
  • the flywheel rotor 111 maintains a transmission connection with the generator rotor of the asynchronous generator 20 in the state of energy storage, and the asynchronous generator 20 idles to stop inputting electric energy to the grid. That is to say, in the energy storage stage, there is no power transmission between the asynchronous generator 20 and the grid, and the asynchronous generator 20 does not generate electricity.
  • the transmission connection between the flywheel rotor 111 and the asynchronous generator 20 is disconnected, that is, the connection between the flywheel rotor 111 and the generator rotor is disconnected, and the flywheel rotor 111 is no longer able to drive the generator rotor, so the asynchronous generator 20 does not generate power, thereby realizing that the asynchronous generator 20 stops inputting electric energy to the grid.
  • the asynchronous generator 20 idles in the energy storage state to realize the technical solution of stopping the input of electric energy to the grid.
  • the flywheel rotor 111 drives the generator rotor to rotate through the transmission shaft 30, and the generator stator is connected to the power grid through the transformer.
  • the flywheel rotor 111 releases the kinetic energy and the speed drops to drive the asynchronous generator 20 to generate electricity, and the asynchronous generator 20 inputs the generated electric energy into the grid.
  • the standby state of the motor 112 in the energy-discharging state means that the motor 112 is not operating, and it does not drive the flywheel rotor 111 to accelerate. That is to say, when the flywheel energy storage system 1 is in the energy release state, there is only energy output in the flywheel energy storage system 1 , but no energy input. When the flywheel energy storage system 1 is in the above energy storage state, there is only energy input in the flywheel energy storage system 1 and no energy output.
  • the current frequency of the generator rotor is changed according to the slip ratio of the asynchronous generator 20, so that the generator stator keeps rotating at a preset magnetic field speed, and the asynchronous generator 20 generates a stable current.
  • the magnetic field speed of the generator stator can be maintained at a stable value, so that the current with a stable frequency required by the grid can be output.
  • the flywheel energy storage system 1 also has a standby state. It can also be said that the flywheel energy storage system 1 also includes a standby stage during operation. When the flywheel energy storage system 1 is in the standby state, the flywheel energy storage system 1 is in the energy maintenance stage, that is, there is no energy input or energy output, and the flywheel energy storage system 1 operates with minimum loss. In the standby state, the motor 112 is on standby, the asynchronous generator 20 is idling, and the flywheel rotor 111 releases a small amount of kinetic energy to keep the generator rotor rotating.
  • the flywheel energy storage system 1 enters a standby state, and the flywheel rotor 111 loses a small amount of kinetic energy to maintain the rotation of the generator rotor of the asynchronous generator 20, ensuring that the flywheel energy storage system System 1 can respond to the next power grid frequency fluctuation in the best state.
  • a preset value for example, the frequency of the power grid is equal to 50 Hz
  • the flywheel energy storage system 1 when the flywheel energy storage system 1 is connected to the grid, it can perform inertia response or frequency regulation on the grid.
  • the motor 112 absorbs the excess electric energy from the power grid to drive the flywheel rotor 111 to increase its speed, so that the electric energy is converted into kinetic energy and stored in the flywheel rotor 111, thereby reducing the frequency of the power grid.
  • the flywheel rotor 111 drives the asynchronous generator 20 to generate electricity, and the speed of the flywheel rotor 111 drops, so that kinetic energy is converted into electrical energy and input to the power grid, thereby increasing the frequency of the power grid.
  • the flywheel energy storage system 1 further includes a flywheel energy storage controller.
  • the flywheel energy storage controller is used to control the energy input and input power of the flywheel energy storage unit 10, that is, the flywheel energy storage controller is used to control whether to input electric energy to the flywheel energy storage unit 10, and is also used to control the input power to the flywheel energy storage unit 10. power of electrical energy.
  • the flywheel energy storage controller is powered by an independent power source to ensure that it will not be affected by fluctuations in the external power grid.
  • the flywheel energy storage controller includes a grid detection module and a motor control module.
  • the power grid detection module is used to detect the current frequency of the power grid.
  • the power grid detection module can monitor the frequency of the power grid in real time, so as to better respond to and regulate the frequency of the power grid.
  • the motor control module when the motor control module receives the current frequency signal of the power grid and judges that it is necessary to start the motor 112 to store energy in the flywheel energy storage unit 10, the motor control module sends a start signal to the motor 112 to start the motor 112, and from absorb electricity from the grid.
  • the motor control module judges according to the current frequency of the power grid that there is no need to store energy in the flywheel energy storage unit 10 , it sends a shutdown signal to the motor 112 to shut down the motor 112 .
  • the motor control module can also determine the magnitude of the input power of the motor 112 according to the current frequency of the grid, and control the power input to the motor 112 .
  • the motor control module determines to change the input power of the motor 112 to adjust the frequency of the power grid to suppress further increase of the power grid frequency.
  • the flywheel energy storage unit 10 can absorb more electric energy, and the rotation speed of the flywheel rotor 111 increases.
  • the greater the frequency deviation of the grid the greater the moment of the flywheel rotor 111 , that is, the greater the input power of the motor 112 . It can be understood that the input power of the motor 112 will not exceed the maximum power it can withstand.
  • the flywheel energy storage system 1 provided in the embodiment of the present application can realize auxiliary services such as power grid disturbance power distribution, inertia response, and primary frequency regulation, and improve the primary frequency regulation and inertia support capabilities of the power system. Compared with traditional mechanical inertia, the flywheel energy storage system 1 provided by the embodiment of the present application can provide faster and more stable frequency control.
  • the flywheel energy storage system 1 further includes a speed change device, which is connected between the flywheel rotor 111 and the asynchronous generator 20, and the speed change device It has an input end and an output end, the flywheel rotor 111 is connected to the input end of the speed change device, the output end of the speed change device is connected to the generator rotor, and the speed change device is used for speed change.
  • the variator also serves to transmit the moment of inertia of the flywheel rotor.
  • the speed change device is used to adjust the speed of the flywheel rotor 111 input to the asynchronous generator 20, and the speed change ratio of the speed change device is the ratio of the input end (the speed of the flywheel rotor 111) to the output end (the speed of the generator rotor) .
  • the output speed of the flywheel rotor 111 can be better adapted to the application range of the speed of the asynchronous generator 20, reducing the burden on the asynchronous generator 20, that is, the setting of the speed change device can make the output speed of the flywheel rotor 111 change to asynchronous
  • the input rotational speed of the generator 20 (the mechanical rotational speed of the generator rotor) is within an ideal range.
  • the ideal range of the input rotational speed of the asynchronous generator 20 is (3000 ⁇ 1000) rpm, when the input rotational speed of the asynchronous generator 20 (the rotational speed of the generator rotor) is within the range of (3000 ⁇ 1000) rpm, the asynchronous generator 20 It is possible to respond more quickly to changes in the rotational speed of the generator rotor to keep the magnetic field rotational speed of the generator stator constant.
  • the output speed of the flywheel rotor 111 can be varied within the ideal range of the input speed of the asynchronous generator 20 by setting a speed change device with an appropriate speed change ratio.
  • the transmission device is a transmission device with a fixed transmission ratio (constant transmission ratio transmission device 41 ), or the transmission device is a transmission device with an adjustable transmission ratio (speed ratio adjustable device 42 ).
  • the transmission device being a transmission device with an adjustable transmission ratio means that the transmission device may be a multi-stage transmission device or a continuously variable transmission device.
  • the speed change device is a multi-stage speed change device, which has multiple speed change ratios, and its speed change ratio can be adjusted according to the rotating speed of the flywheel rotor 111.
  • the speed change device is a step speed change device, and it can continuously adjust its speed change ratio within a certain range.
  • the transmission ratio of the transmission device is 0.03-333.
  • the transmission device is a gear transmission with a one-stage or multi-stage transmission function, a hydraulic torque converter, a magnetic transformer, a permanent magnet transmission or a magnetic coupling transmission device.
  • FIGS. 1-6 Several specific embodiments of the present disclosure are described below according to FIGS. 1-6 .
  • the flywheel energy storage system 1 of this embodiment includes a flywheel rotor 111 , a motor 112 , a wound rotor asynchronous generator 21 and a transmission shaft 30 .
  • the wound rotor asynchronous generator 21 includes a generator rotor and a generator stator.
  • the generator rotor is the input end of the wound rotor asynchronous generator 21 .
  • the flywheel rotor 111 is connected to the generator rotor and can drive the generator rotor to rotate.
  • the motor 112 is located on the side of the flywheel rotor 111 away from the wound rotor asynchronous generator 21, the transmission shaft 30 passes through the flywheel rotor 111 and is connected to the flywheel rotor 111, and one end of the transmission shaft 30 is connected to the output end of the motor 112. The other end of the shaft 30 is connected to the generator rotor of the wound rotor asynchronous generator 21 .
  • the stator of the generator is connected to the grid through a transformer and can input constant frequency current into the grid.
  • the flywheel energy storage system 1 of this embodiment has an energy storage state, an energy release state and a standby state, that is, the working process of the flywheel energy storage system 1 has an energy storage stage, an energy release stage and a standby stage.
  • the generator stator is disconnected from the power grid, the wound rotor asynchronous generator 21 runs idly, the motor 112 draws electric energy from the power grid, the output end of the motor 112 drives the speed of the flywheel rotor 111 to rise through the drive shaft, and the flywheel rotor 111
  • the rising speed stores kinetic energy, that is, electric energy is converted into kinetic energy and stored in the flywheel rotor 111 .
  • the rotational speed of the flywheel rotor 111 increases until it reaches the set rotational speed. It can be understood that in the energy storage stage, the flywheel energy storage system 1 only has energy input but no energy output.
  • the motor 112 In the energy release stage, the motor 112 is on standby, that is, the motor 112 does not input energy to the flywheel rotor 111, the flywheel rotor 111 releases kinetic energy, and the flywheel rotor 111 drives the generator rotor to rotate through the transmission shaft 30, and the speed of the generator rotor is greater than that of the generator stator.
  • Magnetic field speed, winding rotor asynchronous generator 21 generates electricity, and input electric energy with stable frequency to the power grid through the transformer, without using power electronic devices for decoupling, rectification, frequency modulation, and voltage stabilization, which improves the moment of inertia in the power grid and provides power for the power grid Providing necessary voltage and frequency support reduces the risk of large frequency deviations in the grid, enables the power system to operate safely and stably, and improves the grid's ability to efficiently accept new energy.
  • the electric motor 112 is on standby, and the wound rotor asynchronous generator 21 is idling.
  • the generator stator is connected to the grid, its magnetic field speed is stable at 3000rpm, and the frequency of the output current is 50Hz.
  • the flywheel rotor 111 drives the generator rotor to rotate mechanically through the transmission shaft 30, the mechanical speed of the generator rotor is greater than 3000 rpm, and the wound rotor asynchronous generator 21 can generate electricity.
  • slip s (the magnetic field speed r0 of the generator stator-the mechanical speed r1 of the generator rotor)/the magnetic field speed r0 of the generator stator, the mechanical speed r1 of the generator rotor is greater than the magnetic field speed r0 of the generator stator,
  • the slip s of the wound rotor asynchronous generator 21 under the power generation state is a negative value.
  • the current frequency of the generator rotor is adjusted so that the magnetic field speed of the generator stator is constant and is not affected by the change of the speed of the flywheel rotor 111.
  • the wound rotor asynchronous generator 21 Realize constant frequency transmission to the grid.
  • the absolute value of r2 increases so that the field speed r0 of the generator stator can be kept constant.
  • the absolute value of r2 decreases, so that the magnetic field speed r0 of the generator stator can be kept constant.
  • the speed of the flywheel rotor 111 decreases gradually, which drives the speed of the generator rotor to also gradually decrease.
  • the wound rotor asynchronous generator 21 can realize constant frequency power generation.
  • the flywheel energy storage system 1 of this embodiment is described below by taking FIG. Transmission shaft 32 and constant speed ratio transmission device 41 .
  • the flywheel rotor 111, the motor 112, and the wound rotor asynchronous generator 21 are similar to those in the first embodiment, and will not be repeated here, only the differences will be described.
  • the first transmission shaft 31 passes through the flywheel rotor 111 and is connected with the flywheel rotor 111 in transmission, one end of the first transmission shaft 31 is in transmission connection with the output end of the motor 112, and the other end of the first transmission shaft 31 is connected with the fixed
  • the input end of the variable speed ratio transmission device 41 is connected in transmission.
  • One end of the second transmission shaft 32 is connected to the output end of the constant speed ratio transmission device 41, and the other end is connected to the generator rotor.
  • the generator stator is connected to the grid through a transformer and can input constant frequency current to the grid.
  • the gear ratio of the constant gear ratio transmission device 41 is fixed, which is the ratio of the rotational speed of the input end to the rotational speed of the output end.
  • the speed of the flywheel rotor 111 is equal to the speed of the input end of the constant speed ratio transmission device 41, and the speed of the output end of the constant speed ratio speed change device 41 is equal to the speed of the generator rotor.
  • the generator stator is disconnected from the power grid, the wound rotor asynchronous generator 21 runs idly, the motor 112 absorbs electric energy from the power grid, and the output end of the motor 112 drives the speed of the flywheel rotor 111 through the first transmission shaft 31 to increase, and the flywheel
  • the rotational speed of the rotor 111 rises to store kinetic energy, that is, electric energy is converted into kinetic energy and stored in the flywheel rotor 111 .
  • the rotational speed of the flywheel rotor 111 increases until it reaches the set rotational speed. It can be understood that in the energy storage stage, the flywheel energy storage system 1 only has energy input but no energy output.
  • the motor 112 In the energy release stage, the motor 112 is on standby, that is, the motor 112 does not input energy to the flywheel rotor 111, and the flywheel rotor 111 releases kinetic energy, and the flywheel rotor 111 drives the input end of the constant speed ratio transmission device 41 to rotate through the first transmission shaft 31, and the moment of inertia changes from
  • the output end of the constant speed ratio transmission device 41 is output, and the rotating speed of the output end of the constant speed ratio transmission device 41 is related to the input speed of the constant speed ratio transmission device 41 and the speed ratio of the constant speed ratio transmission device 41, the constant speed ratio transmission device
  • the output end of 41 drives the generator rotor to rotate through the second transmission shaft 32, and the wound rotor asynchronous generator 21 generates electricity.
  • the electric motor 112 is on standby, and the wound rotor asynchronous generator 21 is idling.
  • a fixed speed ratio transmission device 41 is provided between the flywheel rotor 111 and the wound rotor asynchronous generator 21, so that the speed of the generator rotor can better adapt to the speed application range of the wound rotor asynchronous generator 21, and reduce the speed of the wound rotor asynchronous generator.
  • the load on the generator 21, that is, the setting of the speed change device can change the output speed of the flywheel rotor 111 to the ideal range of the input speed of the wound rotor asynchronous generator 21 (the mechanical speed of the generator rotor), thereby making the wound rotor asynchronous
  • the generator 21 preferably outputs a stable current through rotor compensation.
  • the ideal range of the input rotational speed of the wound rotor asynchronous generator 21 is (3000 ⁇ 1000) rpm, and by setting a transmission device with a suitable transmission ratio, the output rotational speed of the flywheel rotor 111 can be changed to that of the asynchronous generator 20. Enter the ideal range of the speed.
  • the wound rotor asynchronous generator 21 can respond more quickly to the change of the rotational speed of the generator rotor, To keep the magnetic field speed of the generator stator constant.
  • the transmission ratio of the constant transmission ratio transmission device 41 is 0.03-333.
  • the constant speed ratio transmission device 41 is a gear transmission with a transmission function, a hydraulic torque converter, a magnetic transformer, a permanent magnet transmission or a magnetic coupling transmission device.
  • the flywheel energy storage system 1 of this embodiment is described below by taking FIG. Transmission shaft 32 and gear ratio adjustable device 42 .
  • the flywheel rotor 111, the motor 112, and the wound rotor asynchronous generator 21 are similar to those in the first embodiment, and will not be repeated here, only the differences will be described.
  • the first transmission shaft 31 passes through the flywheel rotor 111 and is connected in transmission with the flywheel rotor 111, one end of the first transmission shaft 31 is in transmission connection with the output end of the motor 112, and the other end of the first transmission shaft 31 is connected with the transmission
  • the input end of the ratio adjustable device 42 is connected by transmission.
  • One end of the second transmission shaft 32 is connected to the output end of the variable speed ratio adjustable device 42, and the other end is connected to the generator rotor.
  • the generator stator is connected to the grid through a transformer and can input constant frequency current to the grid.
  • the variable speed ratio of the variable speed ratio adjustable device 42 is adjustable, and the variable speed ratio of the variable speed ratio adjustable device 42 is the ratio of the rotational speed of the input end to the rotational speed of the output end.
  • variable speed ratio device 42 may be a multi-stage speed change device, that is, the variable speed ratio device 42 has multiple speed ratios, and can be switched according to the rotational speed of the flywheel rotor 111 .
  • the variable speed ratio device 42 can be a continuously variable speed device, that is, the variable speed ratio device 42 can continuously adjust its speed ratio within a certain range.
  • the gear ratio adjustable device 42 is a gear transmission with a multi-stage or continuously variable transmission function, a hydraulic torque converter, a magnetic transformer, a permanent magnet transmission or a magnetic coupling transmission device.
  • the flywheel rotor 111 can be The output speed of the wound rotor asynchronous generator 21 is better transformed into the ideal range of the input speed of the wound rotor asynchronous generator 21, further reducing the current regulation burden of the wound rotor asynchronous generator 21, improving the applicability of the wound rotor asynchronous generator 21, and The rotational speed range of the flywheel rotor 111 can be enlarged.
  • the speed ratio of the variable speed ratio adjustable device 42 When the speed of the flywheel rotor 111 rises, the speed ratio of the variable speed ratio adjustable device 42 can be increased; when the speed of the flywheel rotor 111 decreases, the speed ratio of the variable speed ratio adjustable device 42 can be reduced, so that The output end of the adjustable device 42 is kept within the ideal range of the input rotational speed of the wound rotor asynchronous generator 21, so that the wound rotor asynchronous generator 21 responds quickly to adjust and output constant frequency current to the grid.
  • the flywheel energy storage system 1 of this embodiment includes a flywheel rotor 111 , a motor 112 , a doubly-fed asynchronous generator 22 and a transmission shaft 30 .
  • the double-fed asynchronous generator 22 includes a generator rotor and a generator stator.
  • the generator rotor is the input end of the doubly-fed asynchronous generator 22 , and the flywheel rotor 111 is drivingly connected with the generator rotor and can drive the generator rotor to rotate.
  • the rotor of the generator is connected to the grid through a converter 50, and the stator of the generator is connected to the grid through a transformer.
  • the converter 50 is a bidirectional back-to-back IGBT voltage source converter.
  • Both the generator stator and the generator rotor of the doubly-fed asynchronous generator 22 can exchange power with the grid.
  • the generator rotor extracts power from or transmits power to the grid through the converter 50 to realize asynchronous power generation. That is, by injecting the rotor current into the converter 50, the converter 50 compensates for the difference between the mechanical frequency of the generator rotor and the magnetic field frequency (grid frequency) of the generator stator, or extracts power from the generator rotor.
  • the doubly-fed asynchronous generator 22 can allow variable-speed operation within a defined large range.
  • the power is fed into the generator rotor or extracted from the generator rotor depends on the operating conditions of the double-fed asynchronous generator 22: in the supersynchronous state, that is, the mechanical speed of the generator rotor is greater than the magnetic field speed of the generator stator, and the power is drawn from the generator rotor It is fed into the grid through the converter 50. In the undersynchronous state, that is, the mechanical speed of the generator rotor is lower than the magnetic field speed of the generator stator, the power is transmitted in the opposite direction and fed into the generator rotor from the grid. In both cases (supersynchronous and undersynchronous), the generator stator is able to feed power to the grid.
  • the motor 112 is positioned at the side of the flywheel rotor 111 away from the doubly-fed asynchronous generator 22, the drive shaft 30 passes through the flywheel rotor 111 and is connected with the flywheel rotor 111, and one end of the drive shaft 30 is connected to the output of the motor 112 The other end of the transmission shaft 30 is connected with the generator rotor.
  • the flywheel energy storage system 1 of this embodiment has an energy storage state, an energy release state and a standby state.
  • the generator stator is disconnected from the power grid, the wound rotor asynchronous generator 21 runs idly, the motor 112 draws electric energy from the power grid, the output end of the motor 112 drives the speed of the flywheel rotor 111 to rise through the drive shaft, and the flywheel rotor 111
  • the rising speed stores kinetic energy, that is, electric energy is converted into kinetic energy and stored in the flywheel rotor 111 .
  • the rotational speed of the flywheel rotor 111 increases until it reaches the set rotational speed.
  • the motor 112 In the energy release stage, the motor 112 is on standby, that is, the motor 112 does not input energy to the flywheel rotor 111 , the flywheel rotor 111 releases kinetic energy, and the flywheel rotor 111 drives the generator rotor to rotate through the transmission shaft 30 .
  • the converter 50 According to the rotational speed of the flywheel rotor 111, the converter 50 automatically adjusts the frequency, voltage, amplitude and phase of the generator rotor, so that the doubly-fed asynchronous generator 22 can realize constant frequency power generation at different rotational speeds, satisfying the power load and parallel network requirements.
  • the doubly-fed asynchronous generator 22 and the power system constitute a "flexible connection", that is, the excitation current can be adjusted according to the grid voltage, current and the speed of the generator rotor, and the output current of the generator can be accurately adjusted to make it can meet the requirements.
  • the magnetic field speed r0 of the generator stator the mechanical speed r1 of the generator rotor+the magnetic field speed r2 matched by the generator rotor current, if the magnetic field speed r0 (grid speed) of the generator stator is kept at 3000rpm, then:
  • the motor 112 In the standby state, the motor 112 is on standby, the flywheel rotor 111 consumes a small amount of mechanical energy to maintain the system no-load consumption, and the converter 50 adjusts the rotor winding power of the doubly-fed asynchronous generator 22, so that the doubly-fed asynchronous generator 22 is in a synchronous operation state.
  • the flywheel energy storage system 1 of this embodiment is described below by taking FIG. Shaft 32 and constant speed ratio transmission device 41 .
  • the flywheel rotor 111, the motor 112, and the doubly-fed asynchronous generator 22 are similar to those of the fourth embodiment, and will not be repeated here, only the differences will be described.
  • the first transmission shaft 31 passes through the flywheel rotor 111 and is connected with the flywheel rotor 111.
  • One end of the first transmission shaft 31 is in transmission connection with the output end of the motor 112, and the other end of the first transmission shaft 31 is connected with the fixed
  • the input end of the variable speed ratio transmission device 41 is connected in transmission.
  • One end of the second transmission shaft 32 is connected to the output end of the constant speed ratio transmission device 41, and the other end is connected to the generator rotor.
  • the generator stator is connected to the grid through a transformer and can input constant frequency current to the grid.
  • the gear ratio of the constant gear ratio transmission device 41 is fixed, which is the ratio of the rotational speed of the input end to the rotational speed of the output end.
  • a fixed speed ratio transmission device 41 is provided between the flywheel rotor 111 and the doubly-fed asynchronous generator 22, so that the speed of the generator rotor can better adapt to the speed application range of the doubly-fed asynchronous generator 22, reducing the speed of the doubly-fed asynchronous generator 22. That is, the setting of the transmission device can change the output speed of the flywheel rotor 111 to the ideal range of the input speed of the doubly-fed asynchronous generator 22 (the mechanical speed of the generator rotor), so that the doubly-fed asynchronous generator 22 is better
  • the ground outputs a stable current through the rotor compensation.
  • the transmission ratio of the constant transmission ratio transmission device 41 is 0.03-333.
  • the constant speed ratio transmission device 41 is a gear transmission with a transmission function, a hydraulic torque converter, a magnetic transformer, a permanent magnet transmission or a magnetic coupling transmission device.
  • the flywheel energy storage system 1 of this embodiment is described below by taking FIG. Shaft 32 and gear ratio adjustable device 42 .
  • the variable speed ratio of the variable speed ratio adjustable device 42 is adjustable, and the variable speed ratio of the variable speed ratio adjustable device 42 is the ratio of the rotational speed of the input end to the rotational speed of the output end.
  • variable speed ratio device 42 may be a multi-stage speed change device, that is, the variable speed ratio device 42 has multiple speed ratios, and can be switched according to the rotational speed of the flywheel rotor 111 .
  • the variable speed ratio device 42 can be a continuously variable speed device, that is, the variable speed ratio device 42 can continuously adjust its speed ratio within a certain range.
  • the gear ratio adjustable device 42 is a gear transmission with a multi-stage or continuously variable transmission function, a hydraulic torque converter, a magnetic transformer, a permanent magnet transmission or a magnetic coupling transmission device.
  • the flywheel rotor 111 can be The output speed is better transformed into the ideal range of the input speed of the doubly-fed asynchronous generator 22, further reducing the current regulation burden of the doubly-fed asynchronous generator 22, improving the applicability of the doubly-fed asynchronous generator 22, and expanding the flywheel rotor 111 speed range.
  • the speed ratio of the variable speed ratio adjustable device 42 can be increased; when the speed of the flywheel rotor 111 decreases, the speed ratio of the variable speed ratio adjustable device 42 can be reduced, so that The output end of the adjustable device 42 is kept within the ideal range of the input speed of the doubly-fed asynchronous generator 22, so that it can respond quickly to adjust and output constant-frequency current to the grid.
  • first and second are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features.
  • the features defined as “first” and “second” may explicitly or implicitly include at least one of these features.
  • “plurality” means at least two, such as two, three, etc., unless otherwise specifically defined.
  • a first feature being “on” or “under” a second feature may mean that the first and second features are in direct contact, or that the first and second features are indirect through an intermediary. touch.
  • “above”, “above” and “above” the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature.
  • “Below”, “beneath” and “beneath” the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is less horizontally than the second feature.
  • the terms “one embodiment,” “some embodiments,” “example,” “specific examples,” or “some examples” mean a specific feature, structure, material, or feature described in connection with the embodiment or example. Features are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

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Abstract

一种飞轮储能系统（1），包括：电动机（112）；飞轮转子（111），电动机与飞轮转子相连以驱动飞轮转子旋转；异步发电机（20），异步发电机包括定子和转子，飞轮转子可断开地与转子传动连接以驱动转子转动，定子能够接入电网并向电网中输入具有稳定频率的电能。飞轮储能系统与电网连接而无需采用电力电子装置，能够为电网提供必要的电压和频率支撑，降低了电网出现大的频率偏差的风险。

Description

飞轮储能系统
相关申请的交叉引用
本申请基于申请号为202110854087.9、申请日为2021年7月27日的中国专利申请提出，并要求该中国专利申请的优先权，该中国专利申请的全部内容在此引入本文作为参考。
技术领域
本公开涉及储能技术领域，尤其是涉及一种飞轮储能系统。
背景技术
随着以清洁能源为主的新一轮能源变革的发展，新能源在我国电网中的占比将越来越高。但是，新能源技术中多采用电力电子装置接入电网，而电力电子装置没有转动惯量，无法主动为电网提供必要的电压和频率支撑，也无法提供必要的阻尼作用。尤其是随着通过电力电子装置连接到电网的分布式能源的渗透率越来越高，电网总的转动惯量不断减小，因此当发生重大的负荷或电源突变时电网出现大的频率偏差的风险也不断提高。高比例电力电子装置的接入会导致电网长期处于低惯量水平中，增加系统不平衡功率冲击，这给电力系统安全稳定的运行带来了越来越大的压力。为改善缓解电网运行压力及新能源消纳压力，亟需具备一定的支撑电网动态调整能力的储能系统来提高电网高效接纳新能源的能力。
公开内容
本公开是基于发明人对以下事实和问题的发现和认识做出的：
飞轮储能技术是一种以动能形式存储能量的储能技术，通过电动机/发电机带动转子加速/减速的方式来实现能量的存储/释放。飞轮储能的主要优点是具有快速的爬坡能力、能量转换效率高和使用寿命长等，在提供辅助服务，例如惯量和频率调节等方面具有得天独厚的优势。且飞轮没有任何地理限制，可以轻松安装，具有可推广及可大规模复制的优点。
目前已有的飞轮储能技术均通过电力电子装置辅助电动/发电机进行动能和电能之间的相互转换过程。当系统需要储存电能时，其会将外部输送来的交流电通过AC/DC的方式供给电动机，进而驱动飞轮转子旋转储能；当需要放电时，电力电子装置对飞轮转子的转子转动惯量进行解耦，起到整流、调频、稳压的作用，以满足负载用电需求。但是电力电子装置没有转动惯量，难以参与电网惯量响应，因此，飞轮储能技术无法解决当前电网中由电力电子装置的大规模使用导致的总的转动惯量比例不断减小的问题。
本公开旨在至少在一定程度上解决相关技术中的技术问题之一。为此，本公开提出一种飞轮储能系统。
根据本公开的飞轮储能系统，包括：电动机；飞轮转子，所述电动机与所述飞轮转子相连以驱动所述飞轮转子旋转；异步发电机，所述异步发电机包括定子和转子，所述飞轮转子可断开地与所述转子传动连接以驱动所述转子转动，所述定子能够接入电网并向电网中输入具有稳定频率的电能。
根据本公开实施例提供的飞轮储能系统的飞轮转子与具有变速恒频的功能的异步发电机相连，异步发电机连接电网且能够与电网同频传输，飞轮转子的转速变化不会影响异步发电机向电网中输入恒频电流，因此将本公开实施例提供的飞轮储能系统与电网连接，无需采用电力电子装置解耦、整流、调频、稳压，能够提高电网中的转动惯量，为电网提供必要的电压和频率支撑，降低了电网出现大的频率偏差的风险，使电力系统能够安全稳定的运行，并提高了电网高效接纳新能源的能力。
在一些实施例中，所述电动机与电网相连并用于从电网取电。
在一些实施例中，所述飞轮储能系统具备释能状态和储能状态，
在所述释能状态下，所述电动机待机，所述飞轮转子释放动能驱动所述异步发电机发电，所述异步发电机向电网中输入具有稳定频率的电能，
在所述储能状态下，所述电动机从电网取电以驱动所述飞轮转子旋转，所述异步发电机停止向电网中输入电能。
在一些实施例中，在所述储能状态下，所述异步发电机空转，和/或，所述飞轮转子与所述转子之间的传动连接断开。
在一些实施例中，所述飞轮储能系统具备待机状态，在所述待机状态下，所述电动机待机，所述发电机空转。
在一些实施例中，所述异步发电机为绕线转子异步发电机或双馈异步发电机。
在一些实施例中，飞轮储能系统还包括变速装置，所述变速装置连接在所述飞轮转子与所述异步发电机之间，所述变速装置具有输入端和输出端，所述飞轮转子与所述输入端传动连接，所述输出端与所述转子传动连接，所述变速装置用于传导所述飞轮转子的转动惯量。
在一些实施例中，所述变速装置为具有固定变速比的变速装置，或者，所述变速装置为变速比可调的变速装置。
在一些实施例中，所述变速装置为齿轮变速器、液力变矩器、磁力变液器或永磁变速器。
在一些实施例中，所述飞轮转子的转速为100rpm-1000000rpm，所述变速装置的变速比为0.03-333。
在一些实施例中，飞轮储能系统还包括飞轮储能控制器，所述飞轮储能控制器用于控制所述飞轮转子的能量输入及输入功率。
在一些实施例中，所述飞轮储能控制器包括：
电网检测模块，所述电网检测模块用于检测电网的当前频率；
电动机控制模块，所述电动机控制模块用于根据电网的当前频率控制所述电动机的启闭及输入输出功率。
本公开的附加方面和优点将在下面的描述中部分给出，部分将从下面的描述中变得明显，或通过本公开的实践了解到。
附图说明
图1是根据本公开实施例一的飞轮储能系统的示意图。
图2是根据本公开实施例二的飞轮储能系统的示意图。
图3是根据本公开实施例三的飞轮储能系统的示意图。
图4是根据本公开实施例四的飞轮储能系统的示意图。
图5是根据本公开实施例五的飞轮储能系统的示意图。
图6是根据本公开实施例六的飞轮储能系统的示意图。
图7是根据本公开实施例的飞轮储能控制器的示意图。
附图标记：
飞轮储能系统1；飞轮转子111；电动机112；异步发电机20；绕线转子异步发电机21；双馈异步发电机32；
传动轴30；第一传动轴31；第二传动轴32；定变速比变速装置41；变速比可调装置42；变流器50。
具体实施方式
下面详细描述本公开的实施例，所述实施例的示例在附图中示出。下面通过参考附图描述的实施例是示例性的，旨在用于解释本公开，而不能理解为对本公开的限制。
下面根据图1-图6描述本公开的实施例的飞轮储能系统1的基本结构。如图1-图6所示，飞轮储能系统1包括飞轮转子111、电动机112和异步发电机20。
飞轮转子111的加速能够实现能量的储存，飞轮转子111的减速能够实现能量的释放。其中飞轮转子111与电动机112相连，电动机112用于驱动飞轮转子111旋转。电动机112通过驱动飞轮转子111加速旋转，最终实现电能以动能的形式储存在飞轮储能单元10中。可选地，电动机112与电网相连用于从电网中取电，电动机112从电网中取电驱动飞轮转子111旋转，飞轮转子111的转速上升以储存动能。
异步发电机20包括发电机定子(图中未示出)和发电机转子(图中未示出)。发电机定子通电产生 旋转磁场。飞轮转子111可断开地与发电机转子传动连接，飞轮转子111的转动能够带动发电机转子旋转，发电机转子旋转切割发电机定子产生的旋转磁场，发电机定子的定子绕轴产生感应电势。通过改变通入发电机转子的电流，使发电机定子的旋转磁场的频率保持恒定，发电机定子的定子绕组产生稳定的感应电势。发电机定子能够接入电网并向电网中输入具有稳定频率的电能。
也就是说，异步发电机20具有变速恒频的作用，能够向电网输入恒频电流。异步发电机20向电网稳定输入电能不受飞轮转子111的转速的变化的影响，即使飞轮转子111转速发生改变，异步发电机20也能够向电网稳定输入电能。可选地，发电机定子的旋转磁场的转速(异步发电机20的同步转速、电网转速)为3000rpm，发电机定子能够稳定向电网中输入频率为50Hz的电流。本领域的技术人员能够理解的是，“发电机定子的旋转磁场的转速”不是机械转动转速。
可选地，飞轮储能系统1可以与电网相连以便参与电网惯量响应，将溢出的能量按溢出比例存于飞轮转子111或者从飞轮转子111按缺失比例汲取能量补充电网，降低电网频率波动。
根据本公开实施例提供的飞轮储能系统的飞轮转子与具有变速恒频的功能的异步发电机相连，异步发电机连接电网且能够与电网同频传输，飞轮转子的转速变化不会影响异步发电机向电网中输入恒频电流，因此将本公开实施例提供的飞轮储能系统与电网连接，无需采用电力电子装置解耦、整流、调频、稳压，解决了目前电网中由电力电子装置的使用导致的总的转动惯量不断减小的问题，能够提高电网中的转动惯量，为电网提供必要的电压和频率支撑，降低了电网出现大的频率偏差的风险，使电力系统能够安全稳定的运行，并提高了电网高效接纳新能源的能力。
下面以图1所示的飞轮储能系统1的示意图为例描述本公开提供的飞轮储能系统1的组成、连接关系及运作流程。
在图1所示的实施例中，飞轮储能系统1包括飞轮转子111、电动机112、异步发电机20、传动轴30。
传动轴30贯穿飞轮转子111，传动轴30的一端与电动机112的输出端传动连接，传动轴30的另一端与异步发电机20的发电机转子传动连接。电动机112与飞轮转子111相连，电动机112能够通过传动轴30驱动飞轮转子111的转速上升以储存动能。飞轮转子111能够通过传动轴30驱动异步发电机20的发电机转子转动。异步发电机20的发电机定子通过变压器(图中未示出)与电网相连，向电网供电。
在本实施例中，异步发电机20的发电机转子的机械转速、传动轴30的转速与飞轮转子111的输出转速相等，异步发电机20的发电机定子的磁场转速恒定在3000rpm。异步发电机20的输出频率稳定在50Hz。
本领域的技术人员可以理解的是，飞轮转子111的转速是在不断变化中的，导致发电机转子的机械转速会断变化，因此发电机转子的机械转速与发电机定子的磁场转速很多情况下是异步的。若要使发电机定子的磁场转速保持不变，使其恒频输电，可以通过改变通入发电机转子的电流实现。需要说明的是，国内的电网频率基准线为50Hz，发电机定子的磁场转速可以恒定在3000rpm。国外的电网频率基准线为60Hz，发电机定子的磁场转速可以恒定在3600rpm，即可以根据电网的频率基准，调整发电机定子的磁场转速。
具体地，根据飞轮转子111的转速(发电机转子的转速)与发电机定子的磁场转速之间的差值，改变发电机转子的电流频率，或者，根据异步发电机20的转差率改变发电机转子的电流频率，其中，转差率s＝(发电机定子的磁场转速r0-发电机转子的机械转速r1)/发电机定子的磁场转速r0。
由于发电机定子的磁场转速r0(电网转速)＝发电机转子的机械转速r1(飞轮转子111的转速)+发电机转子电流匹配的磁场转速r2，若保持发电机定子的磁场转速r0(电网转速)为3000rpm，则：
1)当飞轮转子111的转速小于3000rpm，发电机转子电流匹配正的磁场转速，即r2为正值；
2)当飞轮转子111的转速等于3000rpm，发电机定子的磁场转速r0和发电机转子的机械转速r1相同，发电机转子电流匹配的磁场转速为零，即r2为0；
3)当飞轮转子111的转速大于3000rpm，发电机转子电流匹配负的磁场转速，即r2为负值。
需要说明的是，发电机转子电流匹配的磁场转速r2不是机械转速。通过发电机转子旋转产生的机 械转速与发电机转子电流产生的磁场转速相叠加达到发电机定子的磁场转速，也就是电网的转速，实现发电机定子的磁场转速不受飞轮转子111的转速的变化的影响而始终保持恒定，使异步发电机20能够向电网恒频输电，实现异步发电。
也就是说，为了使发电机定子的磁场转速保持恒定，对其设定预设值，根据飞轮转子111当前的转速，调节发电机转子的电流频率，从而实现使发电机定子的磁场转速保持恒定，异步发电机20能够稳定发电。
可选地，异步发电机20为绕线转子异步发电机或双馈异步发电机。
进一步地，本申请实施例提供的飞轮储能系统1具备储能状态和释能状态，且能够在储能状态和释能状态之间切换。也可以说，飞轮储能系统1在运行过程包括储能阶段和释能阶段，储能阶段对应上述储能状态，释能阶段对应上述释能状态。当飞轮储能系统1在储能状态下时，将电能转化为动能储存；当飞轮储能系统1在释能状态下时，释放其储存的动能，并将动能转化为电能输出。
下面以电动机112与电网相连且可从电网中取电，异步发电机20能够向电网中输能为例描述本申请的技术方案，具体如下：
在储能状态下，电动机112运作从电网取电并通过传动轴30驱动飞轮转子111转动，飞轮转子111的转速上升实现储能，且在该状态下异步发电机20停止向电网中输入电能。
可选地，飞轮转子111在电动机112的驱动下转速上升到额定最高转速，当到达额定最高转速后，飞轮转子111完成储能，而后电动机112停止驱动飞轮转子111。可选地，额定最高转速为100rpm-1000000rpm。
在一些实施例中，储能状态下飞轮转子111与异步发电机20的发电机转子之间保持传动连接，异步发电机20空转以实现停止向电网中输入电能。也就是说，在储能阶段，异步发电机20与电网之间的不进行功率传递，异步发电机20不发电。
需要说明的是，在其他实施例中，还可以有其他方式实现异步发电机20停止向电网中输入电能：
例如，在一些可选实施例中，在储能状态下，飞轮转子111与异步发电机20之间断开传动连接，也就是说，飞轮转子111与发电机转子之间的连接断开，飞轮转子111不再能够驱动发电机转子，因此异步发电机20不发电，从而实现异步发电机20停止向电网中输入电能。
优选储能状态下异步发电机20空转以实现停止向电网中输入电能的技术方案。
在释能状态下，电动机112待机，飞轮转子111通过传动轴30驱动发电机转子转动，发电机定子通过变压器连接电网。飞轮转子111释放动能转速下降驱动异步发电机20发电，异步发电机20将产生的电能输入电网。
其中在释能状态下电动机112待机是指，电动机112没有运作，其没有驱动飞轮转子111加速。也就是说，当飞轮储能系统1处于释能状态下时，飞轮储能系统1中只有能量输出，没有能量输入。当飞轮储能系统1处于上述储能状态下时，飞轮储能系统1中只有能量输入，没有能量输出。
需要说明的是，在释能状态下，根据异步发电机20的转差率改变发电机转子的电流频率，使发电机定子保持预设磁场转速转动，异步发电机20产生稳定电流。或者说，通过改变发电机转子的电流频率，发电机定子的磁场转速可以保持在稳定值，从而能够输出电网需求的稳定频率的电流。
在一些实施例中，飞轮储能系统1还具备待机状态。也可以说，飞轮储能系统1在运行过程还包括待机阶段。当飞轮储能系统1在待机状态下时，飞轮储能系统1处于能量保持阶段，即没有能量的输入也没有能量的输出，飞轮储能系统1以最小的损耗运行。在待机状态下，电动机112待机，异步发电机20空转，飞轮转子111释放少量的动能以保持发电机转子转动。
例如，当电网中的频率等于预设值时(例如电网频率等于50Hz)，使飞轮储能系统1进入待机状态，飞轮转子111损耗少量动能以维持异步发电机20发电机转子转动，保证飞轮储能系统1以最佳状态应对下一次电网频率波动。
在一些实施例中，飞轮储能系统1接入电网能够对电网进行惯量响应或调频。当电网的频率上升时，电动机112从电网中吸取溢出的电能，驱动飞轮转子111转速上升，使电能转化为动能储存在飞轮转子111中，从而使得电网的频率降低。当电网的频率下降时，飞轮转子111驱动异步发电机20发电，飞 轮转子111转速下降，使动能转化为电能输入电网，从而使得电网的频率提升。
在一些实施例中，如图7所示，飞轮储能系统1还包括飞轮储能控制器。飞轮储能控制器用于控制飞轮储能单元10的能量输入及输入功率，即飞轮储能控制器用于控制是否向飞轮储能单元10中输入电能，还用于控制向飞轮储能单元10中输入的电能的功率。可选地，飞轮储能控制器由独立电源供电，以保证其不会受外界电网的波动影响。
飞轮储能控制器包括电网检测模块和电动机控制模块。电网检测模块用于检测电网的当前频率。可选地，电网检测模块能够对电网的频率进行实时监控，以便更好地对电网的频率进行响应、调控。
电动机控制模块与电网检测模块之间通讯连接，电网检测模块将检测到的电网的频率传递给电动机控制模块，电动机控制模块接收到频率信号，并根据频率信号控制电动机112的启闭，以及电动机112的输入功率。
也就是说，当电动机控制模块接收到电网的当前频率信号，并判断需要启动电动机112对飞轮储能单元10进行储能时，电动机控制模块向电动机112发送启动信号，使电动机112开启，并从电网中吸收电能。
当电动机控制模块根据电网的当前频率判断出，不需要向飞轮储能单元10储能时，向电动机112发动关闭信号，关闭电动机112。
并且，电动机控制模块还可以根据电网的当前频率判断出电动机112的输入功率的大小，并控制向电动机112输入的功率。
例如，当电网的当前频率上升至大于预设值时，电动机控制模块判断改变电动机112的输入功率以对电网进行调频，抑制电网频率的进一步抬升。通过改变电动机112的输入功率，能够使飞轮储能单元10吸收更多的电能，飞轮转子111的转速增加。并且电网的频率偏差越大，飞轮转子111的力矩越大，即电动机112的输入功率越大。可以理解的是，电动机112的输入功率不会超过其能承受的最大功率。
因此，本申请实施例提供的飞轮储能系统1能够实现对电网的扰动功率分配、惯量响应、一次调频等辅助服务，提高电力系统一次调频及惯量支撑能力。相比于传统机械惯量，本申请实施例提供的飞轮储能系统1能够提供更快速且更稳定的频率控制。
为了使异步发电机20更好地通过转子补偿输出稳定的电流，在一些实施例中，飞轮储能系统1还包括变速装置，变速装置连接在飞轮转子111与异步发电机20之间，变速装置具有输入端和输出端，飞轮转子111与变速装置的输入端传动连接，变速装置的输出端与发电机转子传动连接，变速装置用于变速。变速装置还用于传导所述飞轮转子的转动惯量。
也就是说，变速装置用于对飞轮转子111输入异步发电机20的转速进行调速，变速装置的变速比为输入端(飞轮转子111的转速)与输出端(发电机转子的转速)之比。通过变速装置变速，能够使飞轮转子111的输出转速更好地适应异步发电机20的转速适用范围，减轻异步发电机20的负担，即变速装置的设置可以使飞轮转子111的输出转速变化到异步发电机20的输入转速(发电机转子的机械转速)的理想区间内。
例如，异步发电机20的输入转速的理想区间为(3000±1000)rpm，当异步发电机20的输入转速(发电机转子的转速)在(3000±1000)rpm范围内时，异步发电机20能够对发电机转子的转速变化进行更快速地响应，以保持发电机定子的磁场转速恒定。通过设置具有合适变速比的变速装置，可以使飞轮转子111的输出转速变化到异步发电机20的输入转速的该理想区间内。
可选地，变速装置为具有固定变速比的变速装置(定变速比变速装置41)，或者，变速装置为变速比可调的变速装置(变速比可调装置42)。变速装置为变速比可调的变速装置是指，变速装置可以为多级变速装置或无级变速装置。变速装置为多级变速装置，其具有多个变速比，且可根据飞轮转子111的转速情况调节其变速比，变速装置为级变速装置，其可在一定范围内连续调节其变速比。
可选地，变速装置的变速比为0.03-333。
可选地，变速装置为具有一级或多级变速功能的齿轮变速器、液力变矩器、磁力变液器、永磁变速器或磁耦合器变速装置。
下面根据图1-图6描述本公开的若干具体实施例。
实施例一：
如图1所示，本实施例的飞轮储能系统1包括飞轮转子111、电动机112、绕线转子异步发电机21和传动轴30。绕线转子异步发电机21包括发电机转子和发电机定子，发电机转子为绕线转子异步发电机21的输入端，飞轮转子111与发电机转子传动连接且能够驱动发电机转子转动。
电动机112位于飞轮转子111的远离绕线转子异步发电机21的一侧，传动轴30穿过飞轮转子111并与飞轮转子111传动连接，传动轴30的一端与电动机112的输出端传动连接，传动轴30的另一端与绕线转子异步发电机21的发电机转子相连。发电机定子通过变压器接入电网能够向电网中输入恒频电流。
本实施例的飞轮储能系统1具有储能状态、释能状态和待机状态，即飞轮储能系统1的工作过程具有储能阶段、释能阶段和待机阶段。
在储能阶段，发电机定子与电网断开，绕线转子异步发电机21空转，电动机112从电网中吸取电能，电动机112的输出端通过传动轴驱动飞轮转子111的转速上升，飞轮转子111的转速上升储存动能，即电能转化为动能储存在飞轮转子111中。飞轮转子111的转速上升直至达到设定转速。可以理解的是，在储能阶段飞轮储能系统1只有能量输入没有能量输出。
在释能阶段，电动机112待机，即电动机112不向飞轮转子111输入能量，飞轮转子111释放动能，飞轮转子111通过传动轴30驱动发电机转子转动，且发电机转子的转速大于发电机定子的磁场转速，绕线转子异步发电机21发电，并通过变压器向电网中输入具有稳定频率的电能，无需采用电力电子装置解耦、整流、调频、稳压，提高了电网中的转动惯量，为电网提供必要的电压和频率支撑，降低了电网出现大的频率偏差的风险，使电力系统能够安全稳定的运行，并提高了电网高效接纳新能源的能力。
在待机阶段，电动机112待机，绕线转子异步发电机21空转。
作为示例，发电机定子并网，其磁场转速稳定在3000rpm，输出电流的频率为50Hz。在释能阶段，飞轮转子111通过传动轴30带动发电机转子机械转动，发电机转子的机械转速大于3000rpm，绕线转子异步发电机21能够发电。
根据公式：转差率s＝(发电机定子的磁场转速r0-发电机转子的机械转速r1)/发电机定子的磁场转速r0，发电机转子的机械转速r1大于发电机定子的磁场转速r0，绕线转子异步发电机21发电状态下的转差率s为负值。根据绕线转子异步发电机21的转差率s，调节发电机转子的电流频率，使发电机定子的磁场转速恒定，不受飞轮转子111的转速的变化的影响，绕线转子异步发电机21实现向电网恒频输电。
发电机转子的机械转速r1越大，转差率s的绝对值越大，增大发电机转子的电阻或延长电阻接入时间，调节发电机转子的电流频率，发电机转子电流匹配的磁场转速r2的绝对值增大，从而发电机定子的磁场转速r0能够保持恒定。发电机转子的机械转速r1越小，转差率s的绝对值越小，减小发电机转子的电阻或延长电阻接入时间，调节发电机转子的电流频率，发电机转子电流匹配的磁场转速r2的绝对值减小，从而发电机定子的磁场转速r0能够保持恒定。因此在释能阶段，飞轮转子111的转速逐渐减小，带动发电机转子的转速也逐渐减小，通过上述方法调节发电机转子的电流，绕线转子异步发电机21可以实现恒频发电。
实施例二：
下面以图2为例描述本实施例的飞轮储能系统1，本实施例的飞轮储能系统1包括飞轮转子111、电动机112、绕线转子异步发电机21、第一传动轴31、第二传动轴32和定变速比变速装置41。飞轮转子111、电动机112、绕线转子异步发电机21同实施例一类似，这里不作赘述，只描述区别部分。
如图2所示，第一传动轴31穿过飞轮转子111并与飞轮转子111传动连接，第一传动轴31的一端与电动机112的输出端传动连接，第一传动轴31的另一端与定变速比变速装置41的输入端传动连接。第二传动轴32的一端与定变速比变速装置41的输出端传动连接，另一端与发电机转子相连，发电机定子通过变压器接入电网能够向电网中输入恒频电流。定变速比变速装置41的变速比固定，为输入端转速与输出端转速之比。
在本实施例中，飞轮转子111的转速等于定变速比变速装置41的输入端的转速，定变速比变速装 置41的输出端的转速等于发电机转子的转速。
在储能阶段，发电机定子与电网断开，绕线转子异步发电机21空转，电动机112从电网中吸取电能，电动机112的输出端通过第一传动轴31驱动飞轮转子111的转速上升，飞轮转子111的转速上升储存动能，即电能转化为动能储存在飞轮转子111中。飞轮转子111的转速上升直至达到设定转速。可以理解的是，在储能阶段飞轮储能系统1只有能量输入没有能量输出。
在释能阶段，电动机112待机，即电动机112不向飞轮转子111输入能量，飞轮转子111释放动能，飞轮转子111通过第一传动轴31驱动定变速比变速装置41的输入端旋转，转动惯量从定变速比变速装置41的输出端输出，且定变速比变速装置41的输出端的转速与定变速比变速装置41的输入端转速和定变速比变速装置41的变速比有关，定变速比变速装置41的输出端通过第二传动轴32带动发电机转子转动，绕线转子异步发电机21发电。
在待机阶段，电动机112待机，绕线转子异步发电机21空转。
在飞轮转子111与绕线转子异步发电机21之间设置定变速比变速装置41，可以使发电机转子的转速更好地适应绕线转子异步发电机21的转速适用范围，减轻绕线转子异步发电机21的负担，即变速装置的设置可以使飞轮转子111的输出转速变化到绕线转子异步发电机21的输入转速(发电机转子的机械转速)的理想区间内，从而使绕线转子异步发电机21更好地通过转子补偿输出稳定的电流。
可选地，绕线转子异步发电机21的输入转速的理想区间为(3000±1000)rpm，通过设置具有合适变速比的变速装置，可以使飞轮转子111的输出转速变化到异步发电机20的输入转速的该理想区间内。当绕线转子异步发电机21的输入转速(发电机转子的转速)在(3000±1000)rpm范围内时，绕线转子异步发电机21能够对发电机转子的转速变化进行更快速地响应，以保持发电机定子的磁场转速恒定。
可选地，定变速比变速装置41的变速比为0.03-333。
可选地，定变速比变速装置41为具有变速功能的齿轮变速器、液力变矩器、磁力变液器、永磁变速器或磁耦合器变速装置。
实施例三：
下面以图3为例描述本实施例的飞轮储能系统1，本实施例的飞轮储能系统1包括飞轮转子111、电动机112、绕线转子异步发电机21、第一传动轴31、第二传动轴32和变速比可调装置42。飞轮转子111、电动机112、绕线转子异步发电机21同实施例一类似，这里不作赘述，只描述区别部分。
如图3所示，第一传动轴31穿过飞轮转子111并与飞轮转子111传动连接，第一传动轴31的一端与电动机112的输出端传动连接，第一传动轴31的另一端与变速比可调装置42的输入端传动连接。第二传动轴32的一端与变速比可调装置42的输出端传动连接，另一端与发电机转子相连，发电机定子通过变压器接入电网能够向电网中输入恒频电流。变速比可调装置42的变速比可调，变速比可调装置42的变速比为输入端转速与输出端转速之比。
可选地，变速比可调装置42可以为多级变速装置，即变速比可调装置42具有多个变速比，且可根据飞轮转子111的转速情况进行切换。或者，变速比可调装置42可以为无级变速装置，即变速比可调装置42可在一定范围内连续调节其变速比。
可选地，变速比可调装置42为具有多级或无级变速功能的齿轮变速器、液力变矩器、磁力变液器、永磁变速器或磁耦合器变速装置。
通过在飞轮转子111与绕线转子异步发电机21之间设置变速比可调装置42，并根据飞轮转子111的当前转速适应性地调整变速比可调装置42的变速比，可以使飞轮转子111的输出转速更好地转变到绕线转子异步发电机21的输入转速的理想区间内，进一步减轻绕线转子异步发电机21的电流调节负担，提高绕线转子异步发电机21的适用性，还可以扩大飞轮转子111的转速区间。
当飞轮转子111的转速上升时，可以使变速比可调装置42的变速比增大，当飞轮转子111的转速下降时，可以使变速比可调装置42的变速比减小，以使变速比可调装置42的输出端保持在绕线转子异步发电机21的输入转速的理想区间内，使绕线转子异步发电机21快速响应进行调节，向电网输出恒频电流。
实施例四：
如图4所示，本实施例的飞轮储能系统1包括飞轮转子111、电动机112、双馈异步发电机22和传动轴30。双馈异步发电机22包括发电机转子和发电机定子。
发电机转子为双馈异步发电机22的输入端，飞轮转子111与发电机转子传动连接且能够驱动发电机转子转动。发电机转子通过变流器50与电网相连，发电机定子通过变压器接入电网。其中变流器50为双向背靠背IGBT电压源变流器。
双馈异步发电机22的发电机定子和发电机转子都可以和电网进行功率交换。根据飞轮转子111的转速与发电机定子的磁场转速(电网转速)之间的差值，发电机转子通过变流器50从电网提取功率或向电网输送功率，实现异步发电。也就是说，通过注入变流器50的转子电流，变流器50对发电机转子的机械频率和发电机定子的磁场频率(电网频率)之差进行补偿，或者从发电机转子中提取功率。由此，双馈异步发电机22可以允许在限定的大范围内变速运行。
功率是馈入发电机转子还是从发电机转子提取取决于双馈异步发电机22的运行条件：在超同步状态，即发电机转子的机械转速大于发电机定子的磁场转速，功率从发电机转子通过变流器50馈入电网，在欠同步状态，即发电机转子的机械转速小于发电机定子的磁场转速，功率反方向传送，从电网中馈入发电机转子。在两种情况(超同步和欠同步)下，发电机定子都能够向电网馈电。
如图4所示，电动机112位于飞轮转子111的远离双馈异步发电机22的一侧，传动轴30穿过飞轮转子111并与飞轮转子111传动连接，传动轴30的一端与电动机112的输出端传动连接，传动轴30的另一端与发电机转子相连。
本实施例的飞轮储能系统1具有储能状态、释能状态和待机状态。
在储能阶段，发电机定子与电网断开，绕线转子异步发电机21空转，电动机112从电网中吸取电能，电动机112的输出端通过传动轴驱动飞轮转子111的转速上升，飞轮转子111的转速上升储存动能，即电能转化为动能储存在飞轮转子111中。飞轮转子111的转速上升直至达到设定转速。
在释能阶段，电动机112待机，即电动机112不向飞轮转子111输入能量，飞轮转子111释放动能，飞轮转子111通过传动轴30驱动发电机转子转动。根据飞轮转子111的转速，变流器50自动调节发电机转子的频率、电压、幅值和相位，使双馈异步发电机22可以在不同的转速下实现恒频发电，满足用电负载和并网的要求。由于采用了交流励磁，双馈异步发电机22和电力系统构成了"柔性连接"，即可以根据电网电压、电流和发电机转子的转速来调节励磁电流，精确的调节发电机输出电流，使其能满足要求。
根据公式发电机定子的磁场转速r0＝发电机转子的机械转速r1+发电机转子电流匹配的磁场转速r2，若保持发电机定子的磁场转速r0(电网转速)为3000rpm，则：
1)当发电机转子的机械转速小于3000rpm，双馈异步发电机22处于欠同步状态，发电机转子从电网取电，r2为正值；
2)当发电机转子的机械转速等于3000rpm，发电机转子与发电机定子同步运行发电；
3)当发电机转子的机械转速大于3000rpm，双馈异步发电机22处于超同步状态，发电机转子向电网输电，r2为负值。
在待机状态下，电动机112待机，飞轮转子111损耗少量机械能维持系统空载消耗，变流器50调节双馈异步发电机22的转子绕组电源，使双馈异步发电机22处于同步运行状态。
实施例五：
下面以图5为例描述本实施例的飞轮储能系统1，本实施例的飞轮储能系统1包括飞轮转子111、电动机112、双馈异步发电机22、第一传动轴31、第二传动轴32和定变速比变速装置41。飞轮转子111、电动机112、双馈异步发电机22同实施例四类似，这里不作赘述，只描述区别部分。
如图5所示，第一传动轴31穿过飞轮转子111并与飞轮转子111传动连接，第一传动轴31的一端与电动机112的输出端传动连接，第一传动轴31的另一端与定变速比变速装置41的输入端传动连接。第二传动轴32的一端与定变速比变速装置41的输出端传动连接，另一端与发电机转子相连，发电机定子通过变压器接入电网能够向电网中输入恒频电流。定变速比变速装置41的变速比固定，为输入端转速与输出端转速之比。
在飞轮转子111与双馈异步发电机22之间设置定变速比变速装置41，可以使发电机转子的转速更好地适应双馈异步发电机22的转速适用范围，减轻双馈异步发电机22的负担，即变速装置的设置可以使飞轮转子111的输出转速变化到双馈异步发电机22的输入转速(发电机转子的机械转速)的理想区间内，从而使双馈异步发电机22更好地通过转子补偿输出稳定的电流。
可选地，定变速比变速装置41的变速比为0.03-333。
可选地，定变速比变速装置41为具有变速功能的齿轮变速器、液力变矩器、磁力变液器、永磁变速器或磁耦合器变速装置。
实施例六：
下面以图6为例描述本实施例的飞轮储能系统1，本实施例的飞轮储能系统1包括飞轮转子111、电动机112、双馈异步发电机22、第一传动轴31、第二传动轴32和变速比可调装置42。变速比可调装置42的变速比可调，变速比可调装置42的变速比为输入端转速与输出端转速之比。
可选地，变速比可调装置42可以为多级变速装置，即变速比可调装置42具有多个变速比，且可根据飞轮转子111的转速情况进行切换。或者，变速比可调装置42可以为无级变速装置，即变速比可调装置42可在一定范围内连续调节其变速比。
可选地，变速比可调装置42为具有多级或无级变速功能的齿轮变速器、液力变矩器、磁力变液器、永磁变速器或磁耦合器变速装置。
通过在飞轮转子111与双馈异步发电机22之间设置变速比可调装置42，并根据飞轮转子111的当前转速适应性地调整变速比可调装置42的变速比，可以使飞轮转子111的输出转速更好地转变到双馈异步发电机22的输入转速的理想区间内，进一步减轻双馈异步发电机22的电流调节负担，提高双馈异步发电机22的适用性，还可以扩大飞轮转子111的转速区间。
当飞轮转子111的转速上升时，可以使变速比可调装置42的变速比增大，当飞轮转子111的转速下降时，可以使变速比可调装置42的变速比减小，以使变速比可调装置42的输出端保持在双馈异步发电机22的输入转速的理想区间内，使其能快速响应进行调节，向电网输出恒频电流。
在本公开的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”“内”、“外”、“顺时针”、“逆时针”、“轴向”、“径向”、“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本公开和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本公开的限制。
此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括至少一个该特征。在本公开的描述中，“多个”的含义是至少两个，例如两个，三个等，除非另有明确具体的限定。
在本公开中，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”、“固定”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；可以是机械连接，也可以是电连接或彼此可通讯；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系，除非另有明确的限定。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本公开中的具体含义。
在本公开中，除非另有明确的规定和限定，第一特征在第二特征“上”或“下”可以是第一和第二特征直接接触，或第一和第二特征通过中间媒介间接接触。而且，第一特征在第二特征“之上”、“上方”和“上面”可是第一特征在第二特征正上方或斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”可以是第一特征在第二特征正下方或斜下方，或仅仅表示第一特征水平高度小于第二特征。
在本公开中，术语“一个实施例”、“一些实施例”、“示例”、“具体示例”、或“一些示例”等意指结合该实施例或示例描述的具体特征、结构、材料或者特点包含于本公开的至少一个实施例或示例中。在本说明书中，对上述术语的示意性表述不必须针对的是相同的实施例或示例。而且，描述的具体特征、结构、材料或者特点可以在任一个或多个实施例或示例中以合适的方式结合。此外，在不相互矛盾的情 况下，本领域的技术人员可以将本说明书中描述的不同实施例或示例以及不同实施例或示例的特征进行结合和组合。
尽管上面已经示出和描述了本公开的实施例，可以理解的是，上述实施例是示例性的，不能理解为对本公开的限制，本领域的普通技术人员在本公开的范围内可以对上述实施例进行变化、修改、替换和变型。

Claims (11)

  1. 一种飞轮储能系统，其特征在于，包括：
    电动机；
    飞轮转子，所述电动机与所述飞轮转子相连以驱动所述飞轮转子旋转；
    异步发电机，所述异步发电机包括定子和转子，所述飞轮转子可断开地与所述转子传动连接以驱动所述转子转动，所述定子能够接入电网并向电网中输入具有稳定频率的电能。
  2. 根据权利要求1所述的飞轮储能系统，其特征在于，所述电动机与电网相连并用于从电网取电。
  3. 根据权利要求2所述的飞轮储能系统，其特征在于，所述飞轮储能系统具备释能状态和储能状态，
    在所述释能状态下，所述电动机待机，所述飞轮转子释放动能驱动所述异步发电机发电，所述异步发电机向电网中输入具有稳定频率的电能，
    在所述储能状态下，所述电动机从电网取电以驱动所述飞轮转子旋转，所述异步发电机停止向电网中输入电能。
  4. 根据权利要求3所述的飞轮储能系统，其特征在于，在所述储能状态下，所述异步发电机空转，和/或，所述飞轮转子与所述转子之间的传动连接断开。
  5. 根据权利要求3所述的飞轮储能系统，其特征在于，所述飞轮储能系统具备待机状态，在所述待机状态下，所述电动机待机，所述异步发电机空转。
  6. 根据权利要求1所述的飞轮储能系统，其特征在于，所述异步发电机为绕线转子异步发电机或双馈异步发电机。
  7. 根据权利要求6所述的飞轮储能系统，其特征在于，还包括变速装置，所述变速装置连接在所述飞轮转子与所述异步发电机之间，所述变速装置具有输入端和输出端，所述飞轮转子与所述输入端传动连接，所述输出端与所述转子传动连接，所述变速装置用于传导所述飞轮转子的转动惯量。
  8. 根据权利要求7所述的飞轮储能系统，其特征在于，所述变速装置为具有固定变速比的变速装置，或者，所述变速装置为变速比可调的变速装置。
  9. 根据权利要求7所述的飞轮储能系统，其特征在于，所述变速装置为齿轮变速器、液力变矩器、磁力变液器或永磁变速器。
  10. 根据权利要求7所述的飞轮储能系统，其特征在于，所述飞轮转子的转速为100rpm-1000000rpm，所述变速装置的变速比为0.03-333。
  11. 根据权利要求1所述的飞轮储能系统，其特征在于，还包括飞轮储能控制器，所述飞轮储能控制器用于控制所述飞轮转子的能量输入及输入功率，所述飞轮储能控制器包括：
    电网检测模块，所述电网检测模块用于检测电网的当前频率；
    电动机控制模块，所述电动机控制模块用于根据电网的当前频率控制所述电动机的启闭及输入输出功率。
PCT/CN2022/108087 2021-07-27 2022-07-27 飞轮储能系统 WO2023005950A1 (zh)

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