WO2023088321A1

WO2023088321A1 - Flywheel energy storage system having electromagnetic coupler

Info

Publication number: WO2023088321A1
Application number: PCT/CN2022/132334
Authority: WO
Inventors: 陈俊; 冯晨; 曾子竞; 孙册; 刘腾飞; 张蔚琦; 白宁
Original assignee: 国家电投集团科学技术研究院有限公司
Priority date: 2021-11-16
Filing date: 2022-11-16
Publication date: 2023-05-25

Abstract

Provided in the present disclosure is a flywheel energy storage system having an electromagnetic coupler. The flywheel energy storage system comprises an electric motor, a flywheel rotor, an electromagnetic coupler, a frequency converter and a power generator, wherein the electric motor is connected to the flywheel rotor, so as to drive the flywheel rotor to rotate; and the electromagnetic coupler comprises an outer rotor and an inner rotor, wherein the outer rotor is sleeved on and spaced apart from the inner rotor, the flywheel rotor is in transmission connection with the outer rotor or the inner rotor, and the outer rotor generates a rotating magnetic field to drive the inner rotor to rotate, or the inner rotor generates a rotating magnetic field to drive the outer rotor to rotate. The output rotation speed of the electromagnetic coupler can remain unchanged, such that a power generator can be driven to generate a constant-frequency current, thereby meeting the requirement for transmitting power to a power grid; and there is no need to use a power electronic apparatus, and the moment of inertia in the power grid can be improved, thereby providing necessary voltage and frequency support for the power grid, and improving the capability of the power grid to efficiently receive new energy.

Description

Flywheel energy storage system with electromagnetic coupler

Cross References to Related Applications

This application is based on a Chinese patent application with application number 202111356233.1 and a filing date of November 16, 2021, and a Chinese patent application with application number 202111357475.2 and a filing date of November 16, 2021, and requires the Chinese patent application Right of priority, the entire content of this Chinese patent application is incorporated herein by reference.

technical field

The present disclosure relates to the technical field of energy storage, in particular to a flywheel energy storage system with an electromagnetic coupler.

Background technique

With the development of a new round of energy transformation dominated by clean energy, the proportion of new energy in my country's power grid will become higher and higher. However, in new energy technologies, power electronic devices are mostly used to connect to the grid, and power electronic devices have no moment of inertia, so they cannot actively provide the necessary voltage and frequency support for the grid, nor can they provide the necessary damping effect. Especially with the increasing penetration of distributed energy resources connected to the grid through power electronic devices, the total moment of inertia of the grid continues to decrease, so there is a risk of large frequency deviations in the grid when a major load or power supply mutation occurs Also keep improving. The 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 to the safe and stable operation of the power system. In order to improve the operation pressure of the power grid and the pressure of new energy consumption, 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.

Contents of the invention

The present disclosure is made based on the inventors' discovery and recognition of the following facts and problems:

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. Moreover, 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.

The existing flywheel energy storage technologies all use power electronic devices to assist the motor/generator in the process of mutual conversion between kinetic energy and electric energy. 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. However, 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 with an electromagnetic coupler.

A flywheel energy storage system with an electromagnetic coupler according to the present disclosure includes a motor, a flywheel rotor, an electromagnetic coupler, a frequency converter, and a generator, the motor is connected to the flywheel rotor to drive the flywheel rotor to rotate, and the electromagnetic The coupler includes an outer rotor and an inner rotor, the outer rotor sleeves the inner rotor and is spaced from the inner rotor; the flywheel rotor is in drive connection with the outer rotor, and the outer rotor generates a rotating magnetic field to drive the The inner rotor rotates, the frequency converter is connected with the outer rotor to keep the rotational speed of the rotating magnetic field constant, so that the inner rotor speed remains constant, and the inner rotor is connected to the input end of the generator connected, the generator generates electricity and connects to the power grid and inputs electric energy with a stable frequency into the power grid; or, the flywheel rotor is connected to the inner rotor through transmission, and the inner rotor generates a rotating magnetic field to drive the outer rotor to rotate, so The frequency converter is connected with the outer rotor to change the current frequency of the outer rotor so as to change the magnetic field speed for current matching, so that the mechanical speed of the outer rotor remains constant, and the outer rotor is connected to the input end of the generator The generator is connected to the power grid to generate electricity and input electric energy with a stable frequency into the power grid.

According to the embodiment of the present disclosure, the flywheel rotor of the flywheel energy storage system is connected to the electromagnetic coupler with variable speed function, and the output speed of the electromagnetic coupler can remain unchanged, so it can drive the generator to generate constant frequency current to meet the requirements of power transmission to the grid Require. Since the electromagnetic coupler has a variable speed function, the change in the rotational speed of the flywheel rotor will not affect the input of constant frequency current from the generator to the grid. 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 solve the problem that the total moment of inertia caused by the use of power electronic devices in the current power grid is continuously reduced, and can increase the moment of inertia in the power grid, provide the necessary voltage and frequency support for the power grid, and reduce the The risk of large frequency deviations in the power grid enables the power system to operate safely and stably, and improves the ability of the grid to efficiently accept new energy.

In some embodiments, the inner rotor includes an inner rotor core and an inner rotor winding, the outer rotor includes an outer rotor iron core and an outer rotor winding, and the frequency converter is connected to the outer rotor winding.

In some embodiments, the generator is a synchronous generator.

In some embodiments, the electric motor is connected to the grid and used to take power from the grid, and the flywheel energy storage system has an energy release state and an energy storage state,

In the state of energy release, the motor is on standby, the flywheel rotor releases kinetic energy to drive the generator to generate electricity, and the generator inputs electric energy with a stable frequency to the grid,

In the energy storage state, the electric motor takes power from the grid to drive the flywheel rotor to rotate, and the generator runs idly.

In some embodiments, 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.

In some embodiments, the flywheel energy storage system further includes a transmission device, the flywheel rotor is in transmission connection with the input end of the transmission device, and the output end of the transmission device is in transmission connection with the outer rotor or the inner rotor, The speed change device is used to transfer the moment of inertia of the flywheel rotor.

In some embodiments, 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.

In some embodiments, the transmission device is a gear transmission, a torque converter, a magnetic transformer or a permanent magnet transmission.

In some embodiments, the rotation speed of the flywheel rotor is 100rpm-1000000rpm, and the transmission ratio of the transmission device is 0.03-333.

Additional aspects and advantages of the disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure.

Description of drawings

Fig. 1 is a schematic diagram of a flywheel energy storage system according to Embodiment 1 of the present disclosure.

FIG. 2 is a partial schematic diagram of FIG. 1 .

Fig. 3 is a schematic diagram of a flywheel energy storage system according to Embodiment 2 of the present disclosure.

Fig. 4 is a schematic diagram of a flywheel energy storage system according to Embodiment 3 of the present disclosure.

Fig. 5 is a schematic diagram of a flywheel energy storage system according to Embodiment 4 of the present disclosure.

FIG. 6 is a partial schematic diagram of FIG. 5 .

Fig. 7 is a schematic diagram of a flywheel energy storage system according to Embodiment 5 of the present disclosure.

Fig. 8 is a schematic diagram of a flywheel energy storage system according to Embodiment 6 of the present disclosure.

9 is a schematic diagram of a flywheel energy storage controller according to an embodiment of the disclosure.

Reference signs:

Flywheel energy storage system 1, motor 10, flywheel rotor 20, electromagnetic coupler 30, outer rotor 31, inner rotor 32, frequency converter 40, generator 50, constant speed ratio transmission device 61, speed ratio adjustable device 62, first A transmission shaft 71 , a second transmission shaft 72 , and a third transmission shaft 73 .

Detailed ways

Embodiments of the present disclosure are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the figures are exemplary and are intended to explain the present disclosure and should not be construed as limiting the present disclosure.

The following describes the basic structure of a flywheel energy storage system 1 according to an embodiment of the present disclosure according to FIGS. 1-8 . As shown in FIG. 1 , a flywheel energy storage system 1 includes a motor 10 , a flywheel rotor 20 , an electromagnetic coupler 30 , a frequency converter 40 and a generator 50 .

Acceleration of the flywheel rotor 20 can realize energy storage, and deceleration of the flywheel rotor 20 can realize energy release. Wherein the flywheel rotor 20 is connected with the motor 10, and the motor 10 is used to drive the flywheel rotor 20 to rotate. The electric motor 10 accelerates the rotation by driving the flywheel rotor 20 , and finally the electric energy is stored in the flywheel energy storage unit 10 in the form of kinetic energy. Optionally, the motor 10 is connected to the grid for taking power from the grid, and the motor 10 takes power from the grid to drive the flywheel rotor 20 to rotate, and the speed of the flywheel rotor 20 increases to store kinetic energy.

The electromagnetic coupler 30 includes an outer rotor 31 and an inner rotor 32 , the outer rotor 31 sleeves the inner rotor 32 , and the outer rotor 31 and the inner rotor 32 are spaced apart.

In some embodiments, the flywheel rotor 20 is in drive connection with the outer rotor 31, and the outer rotor 31 generates a rotating magnetic field to drive the inner rotor 32 to rotate. The rotational speed of the rotor 32 can be kept constant. The inner rotor 32 is connected to the input end of the generator 50. Since the rotational speed of the inner rotor 32 can be kept constant, the generator 50 generates electricity and connects it to the grid and inputs electric energy with a stable frequency into the grid. The ratio of the mechanical speed of the outer rotor 31 to the mechanical speed of the inner rotor 32 can be regarded as the transmission ratio of the electromagnetic coupler 30, so the electromagnetic coupler 30 can be regarded as a transmission device with variable transmission ratio. When the flywheel energy storage system 1 provided by the embodiment of the present disclosure generates power, the rotation of the flywheel rotor 20 can drive the outer rotor 31 to rotate, and the frequency converter 40 can supply AC power to the outer rotor 31 .

When the frequency converter 40 inputs alternating current to the outer rotor 31, the outer rotor 31 can generate a rotating magnetic field. In addition, because the outer rotor 31 rotates, the rotational speed of the rotating magnetic field actually generated by the outer rotor 31 is the rotational speed of the rotating magnetic field matched by the current supplied by the frequency converter 40. Superimposed with the mechanical rotational speed of the outer rotor 31, the inner rotor 32 rotates under the action of the rotating magnetic field, and the rotational speed of the inner rotor 32 is equal to the magnetic field rotational speed of the outer rotor 31, thereby realizing the transmission of the moment of inertia.

It should be noted that, according to the difference between the mechanical speed of the outer rotor 31 and the preset speed of the inner rotor 32, by changing the current to the outer rotor 31 through the frequency converter 40, the magnetic field speed matching the current can be changed, so that the outer rotor 31 The rotation speed of the magnetic field is constant, so that the rotation speed of the inner rotor 32 remains constant, and the inner rotor 32 drives the generator 50 to input current with a stable frequency to the grid.

That is to say, the electromagnetic coupler 30 has the function of variable speed, and through the function of the electromagnetic coupler 30 , the generator 50 can input constant frequency current to the power grid. The stable input of electric energy by the generator 50 to the grid is not affected by changes in the rotational speed of the flywheel rotor 20 , even if the rotational speed of the flywheel rotor 20 changes, the generator 50 can stably input electric energy to the grid.

Optionally, the rotational speed of the inner rotor 32 is 3000 rpm, and the generator 50 can stably input current with a frequency of 50 Hz to the grid.

Optionally, 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 20 according to the overflow ratio, or draw energy from the flywheel rotor 20 according to the missing ratio to supplement the grid, reducing grid frequency fluctuations.

In some other embodiments, the flywheel rotor 20 is connected with the inner rotor 32 in transmission, the flywheel rotor 20 is driven to drive the inner rotor 32 to rotate, and the rotation of the inner rotor 32 generates a rotating magnetic field to drive the outer rotor 32 to rotate. The frequency converter 40 is connected with the outer rotor 31, and the frequency converter 40 is used to change the frequency of the current passing into the outer rotor 31, thereby changing the magnetic field speed matched by the current passing into the outer rotor 31, so that the mechanical speed of the outer rotor 31 can be kept constant. The outer rotor 31 is connected to the input end of the generator 50. Since the mechanical speed of the outer rotor 31 can be kept constant, the generator 50 generates electricity and connects to the power grid and inputs electric energy with a stable frequency into the power grid. The ratio of the mechanical speed of the inner rotor 32 to the mechanical speed of the outer rotor 31 can be regarded as the transmission ratio of the electromagnetic coupler 30, so the electromagnetic coupler 30 can be regarded as a transmission device with variable transmission ratio.

When the flywheel energy storage system 1 provided by the embodiment of the present disclosure generates power, the rotation of the flywheel rotor 20 can drive the inner rotor 32 to rotate. The rotation of the inner rotor 32 generates a rotating magnetic field, and the rotation speed of the rotation field of the inner rotor 32 is equal to the mechanical rotation speed of the inner rotor 32 . The outer rotor 31 rotates under the action of the rotating magnetic field, thereby realizing the transmission of the moment of inertia.

The frequency converter 40 supplies alternating current to the outer rotor 31, so that the outer rotor 31 generates a rotating magnetic field. The actual rotational speed of the rotating magnetic field generated by the outer rotor 31 is the ratio of the rotating magnetic field speed matched by the current supplied by the frequency converter 40 and the mechanical speed of the outer rotor 32. overlay. Because the rotating field speed of the outer rotor 31 is equal to the rotating field speed of the inner rotor 32 . According to the difference between the rotational speed of the inner rotor 32 and the preset mechanical rotational speed of the outer rotor 31, by changing the frequency of the current passed into the outer rotor 31 by the frequency converter 40, thereby changing the rotational speed of the rotating field matched by the current, the mechanical rotational speed of the outer rotor 31 can be realized Keeping constant, the outer rotor 31 drives the generator 50 to input current with a stable frequency to the grid.

Optionally, the rotational speed of the outer rotor 31 is 3000 rpm, and the generator 50 can stably input current with a frequency of 50 Hz to the grid.

The composition, connection relationship and operation process of a flywheel energy storage system 1 provided by an embodiment of 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.

In the embodiment shown in FIG. 1 , a flywheel energy storage system 1 includes a motor 10 , a flywheel rotor 20 , an electromagnetic coupler 30 , a frequency converter 40 , a generator 50 and a transmission shaft. The electric motor 10 is connected with the flywheel rotor 20, and the electric motor 10 can drive the speed of the flywheel rotor 20 to increase through the transmission shaft to store kinetic energy. The flywheel rotor 20 can drive the outer rotor 31 of the electromagnetic coupler 30 to rotate through the transmission shaft. The outer rotor 31 generates a rotating magnetic field to drive the inner rotor 32 to rotate at a constant speed. The inner rotor 32 rotates to drive the generator 50 to generate electricity. The generator 50 is connected to the grid through a transformer (not shown in the figure) to supply power to the grid. In this embodiment, the generator 50 is a synchronous generator.

In this embodiment, the mechanical speed of the outer rotor 31 is equal to the output speed of the flywheel rotor 20 , and the mechanical speed of the inner rotor 32 is equal to the input speed of the generator 50 . The mechanical rotational speed of the inner rotor 32 was constant at 3000 rpm. The output frequency of the generator 50 is stabilized at 50 Hz.

It should be noted that the domestic power grid frequency reference line is 50 Hz, and the rotational speed of the inner rotor 32 can be kept constant at 3000 rpm. The grid frequency reference line abroad is 60 Hz, and the speed of the inner rotor 32 can be kept constant at 3600 rpm, that is, the rated speed of the inner rotor 32 can be adjusted according to the grid frequency reference.

Those skilled in the art can understand that the rotational speed of the flywheel rotor 20 is constantly changing, resulting in constant changes in the mechanical rotational speed of the outer rotor 31 . Therefore, if the rotational speed of the inner rotor 32 is to be kept constant, it can be achieved by changing the current passed into the outer rotor 31 .

Specifically, according to the formula: the rotating field speed r0 of the outer rotor 31 = the mechanical speed r1 of the outer rotor 31 + the magnetic field speed r2 matched with the current of the outer rotor 31; the rotating field speed r0 of the outer rotor 31 = the mechanical speed r3 of the inner rotor 32. According to the difference between the rotational speed of the flywheel rotor 20 (the mechanical rotational speed r1 of the outer rotor 31) and the ideal mechanical rotational speed of the inner rotor 32, the frequency of the current transmitted from the frequency converter 40 to the outer rotor 31 is changed to match the magnetic field of the outer rotor 31 current The rotational speed r2 is adjusted to finally make the rotational magnetic field rotational speed r0 of the outer rotor 31 equal to the ideal mechanical rotational speed of the inner rotor 32 .

If the magnetic field speed r0 (grid speed) of the outer rotor 31 is kept at 3000 rpm, then:

1) When the speed of the flywheel rotor 20 is less than 3000rpm, the current of the outer rotor 31 matches the positive magnetic field speed, that is, r2 is a positive value;

2) When the rotational speed of the flywheel rotor 20 is equal to 3000rpm, the magnetic field rotational speed matched by the current of the outer rotor 31 is zero, that is, r2 is 0;

3) When the speed of the flywheel rotor 20 is greater than 3000 rpm, the current of the outer rotor 31 matches the negative magnetic field speed, that is, r2 is a negative value.

It should be noted that the magnetic field speed r2 for current matching of the outer rotor 31 is not a mechanical speed. A positive value of r2 means that the rotation direction of the rotating magnetic field matched by the current of the outer rotor 31 is the same as the mechanical rotation direction of the outer rotor 31 . A negative value of r2 means that the rotation direction of the rotating magnetic field matched by the current of the outer rotor 31 is opposite to the mechanical rotation direction of the outer rotor 31 . The mechanical speed generated by the rotation of the outer rotor 31 and the magnetic field speed generated by the current of the outer rotor 31 are superimposed to reach the ideal speed value of the inner rotor 32, so that the mechanical speed of the inner rotor 32 is not affected by the change of the speed of the flywheel rotor 20 and always maintained constant, so that the generator 50 can transmit power to the grid at a constant frequency to realize synchronous power generation.

That is to say, in order to keep the mechanical speed of the inner rotor 32 constant, a preset value is set for it, and according to the current speed of the flywheel rotor 20, the frequency of the current input from the frequency converter 40 to the outer rotor 31 is adjusted, so that the outer rotor 31 The rotating speed of the magnetic field remains constant, and the generator 50 can generate electricity stably.

In this embodiment, the outer rotor 31 includes an outer rotor iron core and an outer rotor winding, and the frequency converter 40 is connected to the outer rotor winding.

Optionally, the inner rotor 32 includes an inner rotor core and an inner rotor winding.

Further, the flywheel energy storage system 1 provided in the embodiment of the present application 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. When the flywheel energy storage system 1 is in the energy storage state, it converts electrical energy into kinetic energy for storage; when the flywheel energy storage system 1 is in the energy release state, it releases its stored kinetic energy and converts the kinetic energy into electrical energy for output.

Below, the technical solution of the present application is described by taking the motor 10 connected to the grid and taking electricity from the grid, and the generator 50 being able to transmit energy to the grid as an example, as follows:

In the state of energy storage, the electric motor 10 operates to obtain electricity from the grid and drives the flywheel rotor 20 to rotate through the transmission shaft. That is to say, in the energy storage stage, no power transmission is performed between the generator 50 and the grid, and the generator 50 does not generate electricity.

Optionally, the flywheel rotor 20 is driven by the motor 10 to increase its speed to a rated maximum speed. When the rated maximum speed is reached, the flywheel rotor 20 completes energy storage, and then the motor 10 stops driving the flywheel rotor 20 . Optionally, the rated maximum rotational speed is 100rpm-1000000rpm.

In the state of energy release, the motor 10 is on standby, the flywheel rotor 20 drives the outer rotor 31 to rotate through the transmission shaft, the outer rotor 31 rotates to drive the inner rotor 32 to rotate, the inner rotor 32 drives the generator 50 to generate electricity, and the generator 50 is connected to the grid through a transformer. The flywheel rotor 20 releases kinetic energy and the rotational speed drops.

Wherein the standby state of the motor 10 in the energy-discharging state means that the motor 10 is not operating, and it does not drive the flywheel rotor 20 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.

It should be noted that, in the state of energy release, the current frequency of the outer rotor 31 is changed according to the difference between the rotational speed of the flywheel rotor 20 (the mechanical rotational speed of the outer rotor 31) and the predetermined mechanical rotational speed of the inner rotor 32, so that the inner rotor 32 maintains a preset magnetic field Rotating at a high speed, the generator 50 produces a steady current. Moreover, by changing the frequency and amplitude of the current of the outer rotor 31, the electromagnetic moments of the outer rotor 31 and the inner rotor 32 can be adjusted to balance the electromagnetic moments of the outer rotor 31 and the inner rotor 32.

In some embodiments, 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 10 is on standby, the generator 50 is idling, and the flywheel rotor 20 releases a small amount of kinetic energy to keep the outer rotor 31 rotating.

For example, when the frequency in the grid is equal to a preset value (for example, the grid frequency is equal to 50Hz), the flywheel energy storage system 1 enters a standby state, and the flywheel rotor 20 loses a small amount of kinetic energy to maintain the rotation of the outer rotor 31, ensuring that the flywheel energy storage system 1 Optimum for the next grid frequency fluctuation.

In some embodiments, when the flywheel energy storage system 1 is connected to the grid, it can perform inertia response or frequency regulation on the grid. When the frequency of the power grid increases, the motor 10 absorbs the excess electric energy from the power grid to drive the flywheel rotor 20 to rotate at a higher speed, so that the electric energy is converted into kinetic energy and stored in the flywheel rotor 20, thereby reducing the frequency of the power grid. When the frequency of the grid drops, the flywheel rotor 20 drives the generator 50 to generate electricity, and the flywheel rotor 20 rotates at a lower speed, so that kinetic energy is converted into electrical energy and input to the grid, thereby increasing the frequency of the grid.

In some embodiments, as shown in FIG. 9 , 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. Optionally, 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. Optionally, 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 communication connection between the motor control module and the grid detection module, the grid detection module transmits the detected grid frequency to the motor control module, the motor control module receives the frequency signal, and controls the opening and closing of the motor 10 according to the frequency signal, and the motor 10 input power.

That is to say, when the motor control module receives the current frequency signal of the power grid and judges that it is necessary to start the motor 10 to store energy in the flywheel energy storage unit 10, the motor control module sends a start signal to the motor 10 to start the motor 10, and from absorb electricity from the grid.

When 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 10 to shut down the motor 10 .

Moreover, the motor control module can also determine the magnitude of the input power of the motor 10 according to the current frequency of the grid, and control the power input to the motor 10 .

For example, when the current frequency of the grid rises above a preset value, the motor control module determines to change the input power of the motor 10 to adjust the frequency of the grid to suppress further increase of the grid frequency. By changing the input power of the motor 10, the flywheel energy storage unit 10 can absorb more electric energy, and the rotation speed of the flywheel rotor 20 increases. And the greater the frequency deviation of the grid, the greater the moment of the flywheel rotor 20 , that is, the greater the input power of the motor 10 . It can be understood that the input power of the motor 10 will not exceed the maximum power it can withstand.

Therefore, 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.

In order to enable the generator 50 to better output stable current through rotor compensation, in some embodiments, the flywheel energy storage system 1 further includes a speed change device, which is connected between the flywheel rotor 20 and the electromagnetic coupler 30, and the speed change device has The input end and the output end, the flywheel rotor 20 is drivingly connected with the input end of the transmission, the output end of the transmission is connected with the outer rotor 31 of the electromagnetic coupler 30, and the transmission is used for speed change. The variator also serves to transmit the moment of inertia of the flywheel rotor.

That is to say, the speed change device is used to adjust the speed of the flywheel rotor 20 input to the electromagnetic coupler 30, and the speed change ratio of the speed change device is the ratio of the input end (the speed of the flywheel rotor 20) to the output end (the speed of the outer rotor 31). . By changing the speed of the speed change device, the output speed of the flywheel rotor 20 can be better adapted to the application range of the speed of the electromagnetic coupler 30, and the burden on the electromagnetic coupler 30 can be alleviated. The input rotational speed of the coupler 30 (the mechanical rotational speed of the outer rotor 31 ) is within an ideal range.

For example, the ideal range of the input speed of the electromagnetic coupler 30 is (3000±1000) rpm, when the input speed of the electromagnetic coupler 30 (the speed of the outer rotor 31) is within the range of (3000±1000) rpm, the electromagnetic coupler 30 It is possible to respond more quickly to changes in the rotation speed of the outer rotor 31 to keep the rotation speed of the magnetic field of the outer rotor 31 constant. The output rotational speed of the flywheel rotor 20 can be varied within the ideal range of the input rotational speed of the electromagnetic coupler 30 by providing a transmission device with an appropriate transmission ratio.

Optionally, the transmission device is a transmission device with a fixed transmission ratio (constant transmission ratio transmission device 61 ), or the transmission device is a transmission device with an adjustable transmission ratio (speed ratio adjustable device 62 ). 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 20. The speed change device is a step speed change device, and it can continuously adjust its speed change ratio within a certain range.

Optionally, the transmission ratio of the transmission device is 0.03-333.

Optionally, 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.

Several specific embodiments of the present disclosure are described below according to FIGS. 1-4 .

Embodiment one:

As shown in Figures 1 and 2, the flywheel energy storage system 1 of this embodiment includes a motor 10, a flywheel rotor 20, an electromagnetic coupler 30, a frequency converter 40, a generator 50, a first transmission shaft 71, and a second transmission shaft 72 . The electromagnetic coupler 30 includes an outer rotor 31 and an inner rotor 32 , the outer rotor 31 is the input end of the electromagnetic coupler 30 , and the inner rotor 32 is drivingly connected to the input end of the generator 50 .

The motor 10 is located on the side of the flywheel rotor 20 away from the electromagnetic coupler 30, the first transmission shaft 71 passes through the flywheel rotor 20 and is connected with the flywheel rotor 20, and one end of the first transmission shaft 71 of the transmission shaft 30 is connected to the output end of the motor 10. The other end of the first transmission shaft 71 is connected with the outer rotor 31 . One end of the second transmission shaft 72 is in transmission connection with the inner rotor 32 , and the other end of the second transmission shaft 72 is in transmission connection with the input end of the generator 50 .

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.

In the energy storage stage, the generator 50 is idling, and the electric motor 10 absorbs electric energy from the grid. The output end of the electric motor 10 drives the speed of the flywheel rotor 20 to rise through the first drive shaft 71, and the speed of the flywheel rotor 20 rises to store kinetic energy, that is, the electric energy is converted into Kinetic energy is stored in the flywheel rotor 20 . The rotational speed of the flywheel rotor 20 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.

In the energy release stage, the motor 10 is on standby, that is, the motor 10 does not input energy to the flywheel rotor 20, and the flywheel rotor 20 releases kinetic energy. The flywheel rotor 20 drives the outer rotor 31 to rotate through the first transmission shaft 71, and the inner rotor 32 rotates and passes through the second drive shaft 71 to rotate. The shaft 72 drives the generator 50 to generate electricity, and the generator 50 inputs electric energy with a 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 the necessary power for the power grid. The voltage and frequency support reduces the risk of large frequency deviations in the power grid, enables the power system to operate safely and stably, and improves the ability of the grid to efficiently accept new energy.

As an example, in the energy release stage, the generator 50 is connected to the grid, and the frequency of its output current is 50 Hz. According to the difference between the rotational speed of the flywheel rotor 20 (the mechanical rotational speed r1 of the outer rotor 31) and the ideal mechanical rotational speed of the inner rotor 32, the frequency of the current transmitted from the frequency converter 40 to the outer rotor 31 is changed, and the magnetic field for matching the current of the outer rotor 31 is adjusted. The rotation speed is to finally make the rotating field rotation speed r0 of the outer rotor 31 equal to the ideal mechanical rotation speed of the inner rotor 32 . Realize that the mechanical speed of the inner rotor 32 is always constant without being affected by the change of the speed of the flywheel rotor 20, so that the generator 50 can transmit power to the grid at a constant frequency to realize synchronous power generation.

In the standby phase, the motor 10 is on standby and the generator 50 is idling. The flywheel rotor 20 loses a small amount of mechanical energy to maintain the system no-load consumption.

Embodiment two:

The flywheel energy storage system 1 of this embodiment is described below by taking FIG. The transmission device 61 , the first transmission shaft 71 , the second transmission shaft 72 and the third transmission shaft 73 . The flywheel rotor 20, the motor 10, and the electromagnetic coupler 30 are similar to those in the first embodiment, and will not be repeated here, only the differences will be described.

As shown in FIG. 3 , the first transmission shaft 31 passes through the flywheel rotor 20 and is connected in transmission with the flywheel rotor 20 , one end of the first transmission shaft 31 is in transmission connection with the output end of the motor 10 , and the other end of the first transmission shaft 31 is connected to the fixed The input end of the variable speed ratio transmission device 61 is connected in transmission. One end of the second transmission shaft 32 is in transmission connection with the output end of the constant speed ratio transmission device 61 , and the other end is connected with the outer rotor 31 . One end of the third transmission shaft 73 is connected with the inner rotor 32 , and the other end is connected with the input section of the generator 50 . The gear ratio of the constant gear ratio transmission device 61 is fixed, which is the ratio of the rotational speed of the input end to the rotational speed of the output end.

In this embodiment, the rotational speed of the flywheel rotor 20 is equal to the rotational speed of the input end of the constant speed ratio transmission device 61 , and the rotational speed of the output end of the constant speed ratio transmission device 61 is equal to the rotational speed of the outer rotor 31 .

In the energy storage stage, the stator of the generator is disconnected from the grid, the electromagnetic coupler 30 idles, the electric motor 10 absorbs electric energy from the grid, and the output end of the motor 10 drives the speed of the flywheel rotor 20 to rise through the first drive shaft 31, and the flywheel rotor 20 The rising speed stores kinetic energy, that is, electric energy is converted into kinetic energy and stored in the flywheel rotor 20 . The rotational speed of the flywheel rotor 20 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.

In the energy release stage, the motor 10 is on standby, that is, the motor 10 does not input energy to the flywheel rotor 20, and the flywheel rotor 20 releases kinetic energy, and the flywheel rotor 20 drives the input end of the constant speed ratio transmission device 61 to rotate through the first transmission shaft 31, and the moment of inertia changes from The output end of the constant speed ratio speed changer 61 is output, and the rotating speed of the output end of the constant speed change ratio speed changer 61 is related to the input end speed of the constant speed change ratio speed changer 61 and the speed ratio of the constant speed change ratio speed changer 61, the constant speed ratio speed changer The output end of 61 drives the outer rotor 31 to rotate through the second transmission shaft 32 , the rotation of the outer rotor 31 drives the rotation of the inner rotor 32 , and the inner rotor 32 drives the generator 50 to generate electricity through the third transmission shaft 72 .

A fixed speed ratio transmission device 61 is set between the flywheel rotor 20 and the electromagnetic coupler 30, so that the rotating speed of the generator rotor can better adapt to the application range of the electromagnetic coupler 30, and reduce the burden on the electromagnetic coupler 30, that is, the speed change device can make the output speed of the flywheel rotor 20 change to the ideal range of the input speed of the electromagnetic coupler 30 (the mechanical speed of the outer rotor 31), so that the electromagnetic coupler 30 can better output stable current through rotor compensation.

Optionally, the ideal range of the input rotational speed of the electromagnetic coupler 30 is (3000±1000) rpm, and by setting a speed change device with a suitable gear ratio, the output rotational speed of the flywheel rotor 20 can be changed to 100% of the input rotational speed of the electromagnetic coupler 30. within this ideal range. When the input rotational speed of the electromagnetic coupler 30 (the rotational speed of the generator rotor) is within the range of (3000±1000) rpm, the electromagnetic coupler 30 can respond more quickly to the change of the mechanical rotational speed of the outer rotor 31 to maintain the rotational speed of the outer rotor 31 The rotational speed of the magnetic field is constant.

Optionally, the transmission ratio of the constant transmission ratio transmission device 61 is 0.03-333.

Optionally, the constant speed ratio transmission device 61 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.

Embodiment three:

The flywheel energy storage system 1 of this embodiment is described below by taking FIG. Adjusting device 62, first transmission shaft 71, second transmission shaft 72 and third transmission shaft 73. The flywheel rotor 20, the motor 10, and the electromagnetic coupler 30 are similar to those in the first embodiment, and will not be repeated here, only the differences will be described.

As shown in Figure 4, the first transmission shaft 31 passes through the flywheel rotor 20 and is connected with the flywheel rotor 20. One end of the first transmission shaft 31 is connected to the output end of the motor 10, and the other end of the first transmission shaft 31 is connected to the transmission. The input end of the ratio adjustable device 62 is connected by transmission. One end of the second transmission shaft 32 is in transmission connection with the output end of the gear ratio adjustable device 62 , and the other end is connected with the outer rotor 31 . One end of the third transmission shaft 73 is connected with the inner rotor 32 , and the other end is connected with the input section of the generator 50 . The variable speed ratio of the variable speed ratio adjustable device 62 is adjustable, and the variable speed ratio of the variable speed ratio adjustable device 62 is the ratio of the rotational speed of the input end to the rotational speed of the output end.

Optionally, the variable speed ratio device 62 can be a multi-stage speed change device, that is, the variable speed ratio device 62 has multiple speed ratios, and can be switched according to the speed of the flywheel rotor 20 . Alternatively, the variable speed ratio device 62 can be a continuously variable speed device, that is, the variable speed ratio device 62 can continuously adjust its speed ratio within a certain range.

Optionally, the gear ratio adjustable device 62 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.

By setting the variable speed ratio adjustable device 62 between the flywheel rotor 20 and the electromagnetic coupler 30, and adaptively adjusting the variable speed ratio of the variable speed ratio adjustable device 62 according to the current speed of the flywheel rotor 20, the output speed of the flywheel rotor 20 can be Better transition to the ideal range of the input speed of the electromagnetic coupler 30 , further reduce the current regulation burden of the electromagnetic coupler 30 , improve the applicability of the electromagnetic coupler 30 , and expand the speed range of the flywheel rotor 20 .

When the speed of the flywheel rotor 20 rises, the speed ratio of the variable speed ratio adjustable device 62 can be increased; The output end of the adjustable device 62 is kept within the ideal range of the input rotational speed of the electromagnetic coupler 30, so that the electromagnetic coupler 30 responds quickly to adjust and output a constant frequency current to the grid.

The composition, connection relationship and operation process of another flywheel energy storage system 1 provided by the present disclosure will be described below by taking the schematic diagram of the flywheel energy storage system 1 shown in FIG. 5 as an example.

In the embodiment shown in FIG. 5 , the flywheel energy storage system 1 includes a motor 10 , a flywheel rotor 20 , an electromagnetic coupler 30 , a frequency converter 40 , a generator 50 and a transmission shaft. The electric motor 10 is connected with the flywheel rotor 20, and the electric motor 10 can drive the speed of the flywheel rotor 20 to increase through the transmission shaft to store kinetic energy. The flywheel rotor 20 can drive the inner rotor 32 of the electromagnetic coupler 30 to rotate through the transmission shaft. The inner rotor 32 generates a rotating magnetic field to drive the outer rotor 31 to rotate at a constant speed. The outer rotor 31 rotates to drive the generator 50 to generate electricity. The generator 50 is connected to the grid through a transformer (not shown in the figure) to supply power to the grid. In this embodiment, the generator 50 is a synchronous generator.

In this embodiment, the mechanical speed of the inner rotor 32 is equal to the output speed of the flywheel rotor 20 , and the mechanical speed of the outer rotor 31 is equal to the input speed of the generator 50 . The mechanical rotational speed of the outer rotor 31 is constant at 3000 rpm. The output frequency of the generator 50 is stabilized at 50 Hz.

It should be noted that the domestic power grid frequency reference line is 50 Hz, and the rotational speed of the outer rotor 31 can be kept constant at 3000 rpm. The grid frequency reference line in foreign countries is 60Hz, and the rotation speed of the outer rotor 31 can be kept constant at 3600rpm, that is, the rated rotation speed of the outer rotor 31 can be adjusted according to the grid frequency reference.

Those skilled in the art can understand that the rotational speed of the flywheel rotor 20 is constantly changing, resulting in a constant change in the mechanical rotational speed of the inner rotor 32 . Therefore, if the mechanical speed of the outer rotor 31 is to be kept constant, it can be achieved by changing the current passing through the outer rotor 31 .

Specifically, according to the formula: the rotating field speed r0 of the outer rotor 31 = the mechanical speed r1 of the outer rotor 31 + the magnetic field speed r2 of the current matching of the outer rotor 31; the rotating field speed r0 of the outer rotor 31 = the mechanical/rotating field speed of the inner rotor 32 r3. According to the difference between the rotational speed of the flywheel rotor 20 (the mechanical rotational speed r1 of the inner rotor 32) and the ideal mechanical rotational speed of the outer rotor 31, the frequency of the current transmitted from the frequency converter 40 to the outer rotor 31 is changed to match the magnetic field of the outer rotor 31 current The rotational speed r2 is adjusted to finally make the mechanical rotational speed r1 of the outer rotor 31 equal to the ideal mechanical rotational speed of the outer rotor 31 , ie keep constant.

If the mechanical speed r1 of the outer rotor 31 is kept at 3000rpm, then:

1) When the speed of the flywheel rotor 20 is less than 3000 rpm, the current of the outer rotor 31 matches the negative magnetic field speed, that is, r2 is a positive value;

3) When the speed of the flywheel rotor 20 is greater than 3000 rpm, the current of the outer rotor 31 matches the positive magnetic field speed, that is, r2 is a negative value.

It should be noted that the magnetic field speed r2 for current matching of the outer rotor 31 is not a mechanical speed. A positive value of r2 means that the rotation direction of the rotating magnetic field matched by the current of the outer rotor 31 is the same as the mechanical rotation direction of the outer rotor 31 . A negative value of r2 means that the rotation direction of the rotating magnetic field matched by the current of the outer rotor 31 is opposite to the mechanical rotation direction of the outer rotor 31 . The mechanical speed of the outer rotor 31 is always kept constant without being affected by the change of the speed of the flywheel rotor 20, so that the generator 50 can transmit power to the grid at a constant frequency to realize synchronous power generation.

That is to say, in order to keep the mechanical speed of the outer rotor 31 constant, a preset value is set for it, and according to the current speed of the flywheel rotor 20, the frequency of the current input from the frequency converter 40 to the outer rotor 31 is adjusted, so that the outer rotor 31 The mechanical rotational speed of the motor is kept constant, and the generator 50 can generate electricity stably.

In this embodiment, the outer rotor 31 includes an outer rotor iron core and an outer rotor winding, and the frequency converter 40 is connected to the outer rotor winding. The inner rotor 32 includes an inner rotor core and an inner rotor winding.

In the released state, the motor 10 is on standby, the flywheel rotor 20 drives the inner rotor 32 to rotate through the transmission shaft, the inner rotor 32 rotates to drive the outer rotor 31 to rotate, the outer rotor 31 drives the generator 50 to generate electricity, and the generator 50 is connected to the power grid through a transformer. The flywheel rotor 20 releases kinetic energy and the rotational speed drops.

It should be noted that, in the state of energy release, the current frequency of the outer rotor 31 is changed according to the difference between the rotational speed of the flywheel rotor 20 (the mechanical rotational speed of the inner rotor 32) and the predetermined mechanical rotational speed of the outer rotor 31, so that the outer rotor 31 maintains the preset mechanical speed. Rotating at a high speed, the generator 50 produces a steady current. Moreover, by changing the frequency and amplitude of the current of the outer rotor 31, the electromagnetic moments of the inner rotor 32 and the outer rotor 31 can be adjusted to balance the electromagnetic moments of the inner rotor 32 and the outer rotor 31.

In some embodiments, 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 10 is on standby, the generator 50 is idling, and the flywheel rotor 20 releases a small amount of kinetic energy to keep the inner rotor 32 rotating.

For example, when the frequency in the grid is equal to a preset value (for example, the grid frequency is equal to 50 Hz), the flywheel energy storage system 1 enters a standby state, and the flywheel rotor 20 loses a small amount of kinetic energy to maintain the rotation of the inner rotor 32, ensuring that the flywheel energy storage system 1 is Optimum for the next grid frequency fluctuation.

In order to enable the generator 50 to better output stable current through rotor compensation, in some embodiments, the flywheel energy storage system 1 further includes a speed change device, which is connected between the flywheel rotor 20 and the electromagnetic coupler 30, and the speed change device has The input end and the output end, the flywheel rotor 20 is drivingly connected with the input end of the transmission device, the output end of the transmission device is drivingly connected with the inner rotor 32 of the electromagnetic coupler 30, and the transmission device is used for speed change. The variator also serves to transmit the moment of inertia of the flywheel rotor.

That is to say, the speed change device is used to adjust the speed of the flywheel rotor 20 input to the electromagnetic coupler 30, and the speed change ratio of the speed change device is the ratio of the input end (the speed of the flywheel rotor 20) to the output end (the speed of the inner rotor 32). . By changing the speed of the speed change device, the output speed of the flywheel rotor 20 can be better adapted to the application range of the speed of the electromagnetic coupler 30, and the burden on the electromagnetic coupler 30 can be alleviated. The input rotation speed of the coupler 30 (the mechanical rotation speed of the inner rotor 32) is within an ideal range.

For example, the ideal range of the input speed of the electromagnetic coupler 30 is (3000±1000) rpm, when the input speed of the electromagnetic coupler 30 (the speed of the inner rotor 32) is within the range of (3000±1000) rpm, the electromagnetic coupler 30 It is possible to respond more quickly to changes in the rotational speed of the inner rotor 32 to keep the magnetic field rotational speed of the inner rotor 32 constant. The output rotational speed of the flywheel rotor 20 can be varied within the ideal range of the input rotational speed of the electromagnetic coupler 30 by providing a transmission device with an appropriate transmission ratio.

Optionally, the transmission ratio of the transmission device is 0.03-333.

Several specific embodiments of the present disclosure are described below according to FIGS. 5-8 .

Embodiment four:

As shown in Figures 5 and 6, the flywheel energy storage system 1 of this embodiment includes a motor 10, a flywheel rotor 20, an electromagnetic coupler 30, a frequency converter 40, a generator 50, a first transmission shaft 71, and a second transmission shaft 72 . The electromagnetic coupler 30 includes an inner rotor 32 and an outer rotor 31 , the inner rotor 32 is the input end of the electromagnetic coupler 30 , and the outer rotor 31 is in driving connection with the input end of the generator 50 .

The motor 10 is located on the side of the flywheel rotor 20 away from the electromagnetic coupler 30, the first transmission shaft 71 passes through the flywheel rotor 20 and is connected with the flywheel rotor 20, and one end of the first transmission shaft 71 of the transmission shaft 30 is connected to the output end of the motor 10. The other end of the first transmission shaft 71 is connected with the inner rotor 32 . One end of the second transmission shaft 72 is in transmission connection with the outer rotor 31 , and the other end of the second transmission shaft 72 is in transmission connection with the input end of the generator 50 .

In the energy release stage, the motor 10 is on standby, that is, the motor 10 does not input energy to the flywheel rotor 20, and the flywheel rotor 20 releases kinetic energy. The flywheel rotor 20 drives the inner rotor 32 to rotate through the first transmission shaft 71, and the outer rotor 31 rotates and passes through the second transmission shaft. The shaft 72 drives the generator 50 to generate electricity, and the generator 50 inputs electric energy with a 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 the necessary power for the power grid. The voltage and frequency support reduces the risk of large frequency deviations in the power grid, enables the power system to operate safely and stably, and improves the ability of the grid to efficiently accept new energy.

As an example, in the energy release stage, the generator 50 is connected to the grid, and the frequency of its output current is 50 Hz. According to the difference between the rotational speed of the flywheel rotor 20 (the mechanical rotational speed of the inner rotor 32) and the ideal mechanical rotational speed of the outer rotor 31, the frequency of the current transmitted from the frequency converter 40 to the outer rotor 31 is changed, and the magnetic field speed of the outer rotor 31 current matching is adjusted. , finally make the mechanical speed r1 of the outer rotor 31 equal to the ideal mechanical speed of the outer rotor 31 . Realize that the mechanical rotational speed of the outer rotor 31 is not affected by the change of the rotational speed of the flywheel rotor 20 and always keep constant, so that the generator 50 can transmit power to the grid at a constant frequency to realize synchronous power generation.

Embodiment five:

As shown in Fig. 7, the first transmission shaft 31 passes through the flywheel rotor 20 and is connected in transmission with the flywheel rotor 20, one end of the first transmission shaft 31 is in transmission connection with the output end of the motor 10, and the other end of the first transmission shaft 31 is connected The input end of the variable speed ratio transmission device 61 is connected in transmission. One end of the second transmission shaft 32 is in drive connection with the output end of the constant speed ratio transmission device 61 , and the other end is connected with the inner rotor 32 . One end of the third transmission shaft 73 is connected with the outer rotor 31 , and the other end is connected with the input section of the generator 50 . The gear ratio of the constant gear ratio transmission device 61 is fixed, which is the ratio of the rotational speed of the input end to the rotational speed of the output end.

In this embodiment, the rotational speed of the flywheel rotor 20 is equal to the rotational speed of the input end of the constant speed ratio transmission device 61 , and the rotational speed of the output end of the constant speed ratio transmission device 61 is equal to the rotational speed of the inner rotor 32 .

In the energy release stage, the motor 10 is on standby, that is, the motor 10 does not input energy to the flywheel rotor 20, and the flywheel rotor 20 releases kinetic energy, and the flywheel rotor 20 drives the input end of the constant speed ratio transmission device 61 to rotate through the first transmission shaft 31, and the moment of inertia changes from The output end of the constant speed ratio speed changer 61 is output, and the rotating speed of the output end of the constant speed change ratio speed changer 61 is related to the input end speed of the constant speed change ratio speed changer 61 and the speed ratio of the constant speed change ratio speed changer 61, the constant speed ratio speed changer The output end of 61 drives the inner rotor 32 to rotate through the second transmission shaft 32 , the rotation of the inner rotor 32 drives the rotation of the outer rotor 31 , and the outer rotor 31 drives the generator 50 to generate electricity through the third transmission shaft 72 .

A fixed speed ratio transmission device 61 is set between the flywheel rotor 20 and the electromagnetic coupler 30, so that the rotating speed of the generator rotor can better adapt to the application range of the electromagnetic coupler 30, and reduce the burden on the electromagnetic coupler 30, that is, the speed change device can make the output speed of the flywheel rotor 20 change to the ideal range of the input speed of the electromagnetic coupler 30 (the mechanical speed of the inner rotor 32), so that the electromagnetic coupler 30 can better output stable current through rotor compensation.

Optionally, the ideal range of the input rotational speed of the electromagnetic coupler 30 is (3000±1000) rpm, and by setting a speed change device with a suitable gear ratio, the output rotational speed of the flywheel rotor 20 can be changed to 100% of the input rotational speed of the electromagnetic coupler 30. within this ideal range. When the input rotational speed of the electromagnetic coupler 30 (the rotational speed of the generator rotor) is in the range of (3000±1000) rpm, the electromagnetic coupler 30 can respond more quickly to the change of the mechanical rotational speed of the inner rotor 32 to keep the outer rotor 31 The mechanical speed is constant.

Embodiment six:

As shown in Figure 8, the first transmission shaft 31 passes through the flywheel rotor 20 and is connected in transmission with the flywheel rotor 20. One end of the first transmission shaft 31 is in transmission connection with the output end of the motor 10, and the other end of the first transmission shaft 31 is connected to the transmission. The input end of the ratio adjustable device 62 is connected by transmission. One end of the second transmission shaft 32 is in driving connection with the output end of the gear ratio adjustable device 62 , and the other end is connected with the inner rotor 32 . One end of the third transmission shaft 73 is connected with the outer rotor 31 , and the other end is connected with the input section of the generator 50 . The variable speed ratio of the variable speed ratio adjustable device 62 is adjustable, and the variable speed ratio of the variable speed ratio adjustable device 62 is the ratio of the rotational speed of the input end to the rotational speed of the output end.

In describing the present disclosure, it is to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", The orientations or positional relationships indicated by "radial", "circumferential", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying the referred devices or elements Must be in a particular orientation, constructed, and operate in a particular orientation, and thus should not be construed as limiting on the present disclosure.

In addition, the terms "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. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

In this disclosure, terms such as "installation", "connection", "connection" and "fixation" should be interpreted in a broad sense, for example, it may be a fixed connection or a detachable connection, unless otherwise clearly defined and limited. , or integrated; can be mechanically connected, can also be electrically connected or can communicate with each other; can be directly connected, can also be indirectly connected through an intermediary, can be the internal communication of two components or the interaction relationship between two components, Unless expressly defined otherwise. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present disclosure according to specific situations.

In the present disclosure, unless otherwise clearly stated and limited, 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. Moreover, "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.

In this disclosure, 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 can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Although the embodiments of the present disclosure have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limitations on the present disclosure, and those skilled in the art can understand the above-mentioned embodiments within the scope of the present disclosure. The embodiments are subject to changes, modifications, substitutions and variations.

Claims

A flywheel energy storage system with an electromagnetic coupler, characterized in that it includes a motor, a flywheel rotor, an electromagnetic coupler, a frequency converter and a generator,

The motor is connected to the flywheel rotor to drive the flywheel rotor to rotate, the electromagnetic coupler includes an outer rotor and an inner rotor, the outer rotor sleeves the inner rotor and is spaced from the inner rotor;

The flywheel rotor is in drive connection with the outer rotor, the outer rotor generates a rotating magnetic field to drive the inner rotor to rotate, and the frequency converter is connected to the outer rotor to keep the rotational speed of the rotating magnetic field constant, so that The rotational speed of the inner rotor is kept constant, the inner rotor is connected to the input end of the generator, and the generator generates electricity and connects to the power grid and inputs electric energy with a stable frequency into the power grid;

or,

The flywheel rotor is in transmission connection with the inner rotor, the inner rotor generates a rotating magnetic field to drive the outer rotor to rotate, and the frequency converter is connected to the outer rotor to change the current frequency of the outer rotor to change the current matching The rotation speed of the magnetic field is so that the mechanical rotation speed of the outer rotor remains constant. The outer rotor is connected to the input end of the generator, and the generator generates electricity and connects to the grid and inputs electric energy with a stable frequency into the grid.
The flywheel energy storage system with an electromagnetic coupler according to claim 1, wherein the inner rotor includes an inner rotor core and an inner rotor winding, and the outer rotor includes an outer rotor iron core and an outer rotor winding, so The frequency converter is connected to the outer rotor winding.
The flywheel energy storage system with an electromagnetic coupler according to claim 1, wherein the generator is a synchronous generator.
The flywheel energy storage system with an electromagnetic coupler according to claim 1, wherein the motor is connected to the grid and is used to obtain electricity from the grid, and the flywheel energy storage system has an energy release state and an energy storage state,

In the state of energy release, the motor is on standby, the flywheel rotor releases kinetic energy to drive the generator to generate electricity, and the generator inputs electric energy with a stable frequency to the grid,

In the energy storage state, the electric motor takes power from the grid to drive the flywheel rotor to rotate, and the generator runs idly.
The flywheel energy storage system with an electromagnetic coupler according to claim 4, wherein 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 flywheel energy storage system with an electromagnetic coupler according to claim 1, further comprising a speed change device, the flywheel rotor is in transmission connection with the input end of the speed change device, and the output end of the speed change device is connected to the speed change device The outer rotor or the inner rotor is connected in transmission, and the speed change device is used to transmit the moment of inertia of the flywheel rotor.
The flywheel energy storage system with an electromagnetic coupler according to claim 6, wherein the speed change device is a speed change device with a fixed speed change ratio.
The flywheel energy storage system with electromagnetic coupler according to claim 6, characterized in that, the transmission device is a transmission device with an adjustable transmission ratio.
The flywheel energy storage system with electromagnetic coupling according to claim 7 or 8, characterized in that the transmission device is a gear transmission, a hydraulic torque converter, a magnetic transformer or a permanent magnet transmission.
The flywheel energy storage system with electromagnetic coupler according to claim 6, characterized in that, the rotation speed of the flywheel rotor is 100rpm-1000000rpm, and the transmission ratio of the transmission device is 0.03-333.