Flywheel synchronous grid-connected system of electro-magnetic synchronous motor interface based on electromagnetic driving device

Abstract

The invention discloses a flywheel synchronous grid-connected system of an electro-magnetic synchronous motor interface based on an electromagnetic driving device, and the system comprises a flywheel which is located in a vacuum cavity; a rotating shaft of the flywheel rotor is connected with a conductor disc of the electromagnetic driving device and is fixed with the supporting device through a magnetic suspension bearing, and the flywheel rotor and the conductor disc of the electromagnetic driving device are both located in the vacuum cavity; the electromagnetic driving device comprises a conductor disc and a magnet disc, the conductor disc is connected with a rotor of the flywheel and placed in the vacuum cavity, and the magnet disc is connected with a main shaft of the synchronous motor and located in the atmospheric environment; the synchronous motor is connected with the electromagnetic disc and is located in the atmospheric environment; and the controller is used for monitoring and controlling the electrical signal and the rotating speed signal in real time. According to the flywheel energy storage system, speed regulation is convenient, the dynamic sealing problem does not exist, synchronous grid connection and grid disconnection of the flywheel can be smoothly achieved, the system inertia is flexible and adjustable, and the flywheel energy storage system has the advantages of high efficiency, high inertia and rapid frequency and voltage regulation.

Description

Technical Field

[0001] This invention relates to the field of novel energy storage equipment, and more specifically, to a flywheel synchronous grid-connected system based on an electrically excited synchronous motor interface of an electromagnetic drive device. Background Technology

[0002] The mechanical inertia of a synchronous motor is proportional to the mass and radius of its shaft. Traditional synchronous motor shafts have limited dimensions and are relatively lightweight, resulting in limited inertia support. Adding a flywheel rotor to the synchronous motor shaft can increase the mechanical inertia several times over, enabling grid connection of the flywheel rotor to the synchronous motor interface. This flywheel grid connection technology faces two major challenges: first, how to achieve cross-environment coupling between the flywheel rotor in a vacuum environment and the synchronous motor in an atmospheric environment, a process with significant technical difficulties in dynamic sealing technology; and second, how to achieve speed regulation of the flywheel rotor. Large-capacity flywheel energy storage systems require large-capacity motors, and vacuum cooling of the motor is a major technical challenge, posing a hurdle to the development of large-capacity flywheel energy storage technology. Existing solutions mostly employ dynamic sealing technology to achieve shaft coupling between the flywheel rotor in a vacuum environment and the motor in an atmospheric environment. However, dynamic sealing technology causes a continuous decrease in the vacuum level of the flywheel rotor's vacuum chamber, and the technology itself is complex to manufacture and maintain. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a flywheel synchronous grid-connected system based on an electromagnetically driven synchronous motor interface, enabling the integration of the flywheel rotor and synchronous motor across vacuum and atmospheric environments. The main structure of this system consists of a synchronous motor, an electromagnetic drive device magnet disk, a non-metallic window, an electromagnetic drive device metal disk, and a flywheel rotor. The controller can monitor and control parameters such as active power, reactive power, flywheel speed, synchronous motor speed, and excitation current output by the system, and display the monitoring signals and control actions in real time via a host computer.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A flywheel synchronous grid-connected system based on an electrically excited synchronous motor interface with an electromagnetic drive device includes:

[0006] The flywheel is located inside the vacuum chamber; the rotation shaft of the flywheel rotor is connected to the conductor disk of the electromagnetic drive device and is fixed to the support device through magnetic levitation bearings, and both the flywheel rotor and the conductor disk of the electromagnetic drive device are inside the vacuum chamber.

[0007] Vacuum cavity;

[0008] An electromagnetic drive device includes a conductor disk and a magnet disk. The conductor disk is connected to the rotor of a flywheel and placed in a vacuum chamber, while the magnet disk is connected to the main shaft of a synchronous motor and is located in an atmospheric environment. A non-metallic window is provided in the vacuum chamber between the conductor disk and the magnet disk. The conductor disk and the magnet disk are not in contact; they are completely isolated from the environment and achieve magnetic coupling drive through the non-metallic window of the vacuum chamber.

[0009] Synchronous motor, the synchronous motor is connected to an electric magnetic disk and is in an atmospheric environment;

[0010] The controller is used to monitor and control the electrical and speed signals of the flywheel rotor, electromagnetic drive device, and synchronous motor in real time, and displays the collected results and control actions in real time through the host computer.

[0011] Beneficial effects:

[0012] This invention proposes a solution to the dynamic sealing problem using an electromagnetic drive device. In this invention, the flywheel rotor and the synchronous motor shaft achieve non-contact coupling based on electromagnetic drive, effectively solving the leakage and maintenance problems inherent in traditional dynamic sealing technologies, and improving the control flexibility of the flywheel speed. Furthermore, by connecting the flywheel rotor to the grid via an electrically excited synchronous motor, the short-circuit current capacity and reactive voltage output capacity of the electrically excited synchronous motor are far superior to the power electronic devices used in traditional flywheel energy storage, offering significant voltage regulation advantages. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a flywheel synchronous grid-connected system based on an electrically excited synchronous motor interface of an electromagnetic drive device according to the present invention.

[0014] Figure 2 This is a schematic diagram of the electromagnetic drive used in this invention;

[0015] Figure label:

[0016] 1-Flywheel; 2-Vacuum cavity; 3-Magnetic levitation bearing; 4-Conductor disk; 5-Non-metallic window; 6-Magnetic disk; 7-Synchronous motor; 8-Grid connection interface; 9-Power grid system; 10-Power grid dispatching command; 11-Controller; 12-Acquisition and control circuit; 13-Electromagnetic coil of the electromagnetic drive device magnetic disk. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0018] Achieving shaft system integration between an inertial flywheel and a synchronous motor across vacuum and atmospheric environments is a significant challenge. Furthermore, traditional flywheel energy storage and grid connection utilizes power electronic circuits, leading to decoupling of mechanical inertia from the power grid. This invention proposes a non-contact coupling method using an electromagnetic drive device between the inertial flywheel and the synchronous motor, eliminating dynamic sealing links. The synchronous motor replaces the power electronic device as the grid connection interface, enabling efficient frequency and voltage regulation support for the power system.

[0019] Figure 1 This is a schematic diagram of a flywheel synchronous grid-connected system based on an electrically excited synchronous motor interface with an electromagnetic drive device, according to the present invention. Figure 1 As shown, the system includes:

[0020] Flywheel 1 is located inside vacuum chamber 2; the rotation shaft of the flywheel rotor is connected to the conductor disk 4 of the electromagnetic drive device and is fixed to the support device through magnetic levitation bearings, and both the flywheel rotor and the conductor disk 4 of the electromagnetic drive device are inside vacuum chamber 2.

[0021] Vacuum cavity 2;

[0022] The electromagnetic drive device includes a conductor disk 4 and a magnet disk 6. The conductor disk 4 is connected to the rotor of the flywheel 1 and placed in a vacuum chamber 2. The magnet disk 6 is connected to the main shaft of the synchronous motor 7 and is located in an atmospheric environment. A non-metallic window 5 is provided in the vacuum chamber 2 between the conductor disk 4 and the magnet disk 6 to improve torque transmission capability. The conductor disk 4 and the magnet disk 6 are not in contact; they are completely isolated across the environment and achieve magnetic coupling drive through the non-metallic window 5 of the vacuum chamber 2.

[0023] Synchronous motor 7 is connected to electric disk 6 and is in an atmospheric environment;

[0024] The controller 11 is used to monitor and control the electrical and speed signals of the rotor of the flywheel 1, the electromagnetic drive device, and the synchronous motor 7 in real time, and to display the collected results and control actions in real time through the host computer.

[0025] The flywheel rotor synchronous grid-connected system adopts a vertical structure. From top to bottom, the system consists of a synchronous motor 7, an electromagnetic drive device, and a flywheel rotor. The grid connection interface 8 is the stator three-phase winding of the synchronous motor 7. The flywheel rotor and the synchronous motor 7 are coupled through the electromagnetic drive device.

[0026] The slip of the flywheel rotor and the synchronous motor 7 is between 15% and 0.5%.

[0027] The bearings between the synchronous motor 7 and the electromagnetic drive device are both magnetic levitation bearings.

[0028] Under fault conditions, the synchronous motor 7 has strong transient overload capacity and can withstand 4 to 5 times the rated overload current for a short time, which can effectively improve the transient response characteristics of the flywheel energy storage system.

[0029] The synchronous motor 7 adopts an electrically excited synchronous motor structure, which can flexibly switch between two working states: motoring and generating. The output reactive power can be adjusted by the rotor excitation current.

[0030] The electromagnetic drive device consists of a magnet disk and a conductor disk. The two disks are non-contact and aligned axially. The conductor disk 4 is made of a high-conductivity material such as copper or an alloy. The magnet disk 6 consists of a yoke disk and electromagnetic coils. Several electromagnetic coils 13 are arranged along the circumference of the magnet disk 6, such as... Figure 2 As shown. The magnetic fields generated by each electromagnetic coil 13 are arranged at intervals, meaning that the magnetic fields generated by adjacent electromagnetic coils are in opposite directions. The magnitude and direction of the magnetic field of each electromagnetic coil are controlled by the controller 11.

[0031] The inertial response and active power support of a flywheel energy storage system are transient self-excited, while the voltage support is controlled by a controller.

[0032] The control strategy of controller 11 is to control the current amplitude of magnet disk 6 during the response to grid frequency and voltage regulation to ensure that the flywheel rotor and synchronous motor 7 do not lose synchronization, and to adjust the excitation current of synchronous motor 7 to achieve reactive power output. The controller 11 uses a DSP or FPGA chip. When the voltage of the grid system 9 is disturbed, controller 11 controls the excitation regulation device of synchronous motor 7 to stabilize the voltage of the grid system 9; when the frequency of the grid system 9 fluctuates, controller 11 controls the current of magnet disk 6 to ensure the torque stability between synchronous motor 7 and flywheel rotor 1, avoid speed loss, and realize the spontaneous response of flywheel rotor 1 to the frequency regulation requirements of grid system 9.

[0033] The controller 11 responds in real-time to the power system dispatching instructions 10 of the power grid system 9. Its control objective is to quickly respond to the inertial support requirements, active power support requirements, reactive power support requirements, and frequency and voltage regulation requirements of the power grid system. The controlled parameters of the controller 11 include the speed and acceleration of the flywheel 1, the speed and acceleration of the electromagnetic drive device, the current of the magnet disk 6, and the speed and excitation current of the synchronous motor 7. The controller 11 uses the acquisition and control circuit 12 to connect to the flywheel 1, electromagnetic drive device, synchronous motor 7, and other equipment of the flywheel energy storage system, enabling real-time acquisition and control of the controlled parameters. The acquisition and control circuit 12 can be a combination of signaling circuits and power circuits, including voltage and current detection circuits, frequency sampling circuits, and speed and torque detection circuits. The controller 11 can also uniformly complete the real-time acquisition and control of the following parameters: rotor current and voltage of the synchronous motor 7, speed of the synchronous motor 7, rotor speed of the flywheel, speed of the conductor disk 4, speed of the magnet disk 6, and current amplitude of the electromagnetic coil of the magnet disk 6.

[0034] The excitation winding current of the synchronous motor 7 is controlled by the controller 11. The controller 11 adjusts the amplitude of the excitation winding current according to the power system dispatch instruction 10 in order to obtain the grid connection voltage required for the stability of the power grid system 9.

[0035] Bearings 3 are installed on the rotor shaft of flywheel 1, the rotor shaft of electromagnetic drive device, and the main shaft of synchronous motor 7.

[0036] The electromagnetic drive device adjusts the amplitude and frequency of its winding current using controller 11. The specific principle of the electromagnetic drive device is as follows: the magnet disk 6 is driven to rotate by the synchronous motor 7. The relative slip between the conductor disk 4 and the magnet disk 6 generates eddy currents on the surface of the conductor disk 4. These eddy currents generate a driving force in the magnetic field environment of the magnet disk 6, thereby realizing the interactive transfer of energy and torque between the flywheel 1 and the synchronous motor 7. The charging and discharging of the flywheel energy storage system is completed by controlling the magnitude of the electromagnetic force of the magnet disk 6. Specifically, when the magnet disk 6 rotates, the magnetic field generated by the electromagnetic coil 13 on the surface of the magnet disk 6 also rotates, thereby generating eddy currents on the surface of the conductor disk 4. These eddy currents generate torque in the magnetic field generated by the electromagnetic coil 13, which in turn drives the conductor disk 4 to rotate.

[0037] When the grid frequency fluctuates, the main shaft of the synchronous motor 7 is coupled with the grid frequency, and the flywheel rotor is coupled with the rotational speed of the synchronous motor 7. The flywheel rotor can spontaneously provide mechanical inertia and spontaneously complete the charging and discharging of the flywheel energy storage system, participating in the primary frequency regulation of the grid. When a grid voltage regulation demand is received, the controller 11 controls the excitation regulation device of the synchronous motor 7 to regulate the voltage of the grid connection interface 8, thereby stabilizing the grid voltage.

[0038] The flywheel energy storage system proposed in this invention is easy to adjust, does not have dynamic sealing problems, and can smoothly achieve synchronous grid connection and off-grid operation of the flywheel. It has excellent advantages in high efficiency, high inertia and fast frequency and voltage regulation.

[0039] Although the invention has been described with respect to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes, and not for the purpose of explaining or limiting the subject matter of the invention.

Claims

1. A flywheel synchronous grid-connected system based on an electrically excited synchronous motor interface with an electromagnetic drive device, characterized in that, include: The flywheel (1) is located inside the vacuum chamber (2); the rotating shaft of the flywheel rotor is connected to the conductor disk (4) of the electromagnetic drive device and is fixed to the support device through the magnetic levitation bearing (3), and both the flywheel rotor and the conductor disk (4) of the electromagnetic drive device are inside the vacuum chamber (2); Vacuum cavity (2); The electromagnetic drive device includes a conductor disk (4) and a magnet disk (6). The conductor disk (4) is connected to the rotor of the flywheel (1) and placed in a vacuum chamber (2). The magnet disk (6) is connected to the main shaft of the synchronous motor (7) and is in an atmospheric environment. The vacuum chamber (2) between the conductor disk (4) and the magnet disk (6) has a non-metallic window (5). The conductor disk (4) and the magnet disk (6) are not in contact and are completely isolated across the environment. The magnetic drive is achieved through the non-metallic window (5) of the vacuum chamber (2). Synchronous motor (7), synchronous motor 7 is connected to magnet disk (6) and is in an atmospheric environment; The controller (11) is used to monitor and control the electrical and speed signals of the rotor of the flywheel (1), the electromagnetic drive device and the synchronous motor (7) in real time, and to display the acquisition results and control actions in real time through the host computer.

2. The system according to claim 1, characterized in that, The system adopts a vertical structure. From top to bottom, the system consists of a synchronous motor (7), an electromagnetic drive device, and a flywheel rotor. The grid connection interface (8) uses the stator side three-phase winding of the synchronous motor (7).

3. The system according to claim 1, characterized in that, The synchronous motor (7) is an electrically excited synchronous motor, which can flexibly switch between two working states: motoring and power generation. The output reactive power is adjusted by the rotor excitation current.

4. The system according to claim 1, characterized in that, The conductor disk (4) of the electromagnetic drive device is made of a high conductivity material including copper or alloy, and the magnet disk (6) is composed of a yoke disk and an electromagnetic coil (13).

5. The system according to claim 4, characterized in that, The magnet disk (6) has several electromagnetic coils (13) arranged around its circumference. The magnetic field generated by each electromagnetic coil (13) is arranged at intervals, that is, the magnetic field generated by adjacent electromagnetic coils is opposite in direction. The magnitude and direction of the magnetic field of each electromagnetic coil are controlled by the controller (11).

6. The system according to claim 1, characterized in that, The slip of the flywheel rotor and the synchronous motor (7) is between 15% and 0.5%.

7. The system according to claim 1, characterized in that, When the voltage of the power grid system (9) is disturbed, the controller (11) controls the excitation regulation device of the synchronous motor (7) to stabilize the voltage of the power grid system (9); when the frequency of the power grid system (9) fluctuates, the controller (11) controls the current of the magnet disk (6) to ensure the stability of the torque between the synchronous motor (7) and the flywheel rotor, avoid speed loss, and realize the spontaneous response of the flywheel rotor to the frequency regulation requirements of the power grid system (9).

8. The system according to claim 1, characterized in that, The real-time acquisition and control of the rotor current and voltage of the synchronous motor (7), the speed of the synchronous motor (7), the speed of the flywheel rotor, the speed of the conductor disk (4), the speed of the magnet disk (6), and the current amplitude of the electromagnetic coil of the magnet disk (6) are all completed by the controller (11).

9. The system according to claim 8, characterized in that, The controller (11) is configured to control the voltage of the grid interface (8) by adjusting the excitation current of the synchronous motor (7).

10. The system according to claim 8, characterized in that, The controller (11) uses the acquisition control circuit (12) to connect the flywheel (1), the electromagnetic drive device, and the synchronous motor (7) to realize the real-time acquisition and control of the controlled parameters.

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