Flywheel energy storage device with eccentricity real-time monitoring and magnetic suspension control functions

Abstract

The invention discloses a flywheel energy storage device which comprises a flywheel with a rotating shaft, a magnetic bearing for supporting the rotating shaft, a vacuum cover, an integrated motor for bidirectionally converting electric energy and kinetic energy between the flywheel and electric equipment, and a control system which comprises a displacement sensor capable of monitoring the eccentricity of the flywheel in real time. The magnetic bearing comprises an electromagnetic bearing and / or a permanent magnet bearing, and the magnetic suspension controller adjusts electromagnetic force in the electromagnetic bearing through an algorithm so as to offset centrifugal force brought by eccentricity of the flywheel. The algorithm is a PID control algorithm. The electromagnetic bearing is a low-temperature superconducting magnetic bearing. The integrated motor is connected with the oil pump, and the oil pump can be started to drive the hydraulic motor to link the transmission and the permanent magnet generator for power generation. The eccentric amount of the flywheel is monitored in real time through the displacement sensor, the electromagnetic force of the electromagnetic bearing is dynamically adjusted, the influence of centrifugal force on the flywheel is counteracted, the phenomenon that vibration is intensified due to high-speed rotation is avoided, and stability and safety are improved.

Description

Technical Field

[0001] This application relates to the field of flywheel energy storage technology, and more specifically, to a flywheel energy storage device with real-time monitoring of eccentricity and magnetic levitation control. Background Technology

[0002] A flywheel energy storage device is an energy storage device that stores kinetic energy through a high-speed rotating flywheel and converts that kinetic energy into electrical energy when needed. Traditional flywheel energy storage devices typically consist of three main modules: a mechanical system, an energy conversion system, and a control system. The mechanical system includes the flywheel rotor, support structure, and vacuum chamber; the energy conversion system is primarily responsible for the bidirectional conversion between electrical and kinetic energy, generally employing an integrated motor design that acts both as a motor to drive the flywheel to accelerate energy storage and as a generator to convert kinetic energy into electrical energy during discharge; the control system is responsible for monitoring the flywheel's operation, adjusting its status, and managing charging and discharging to ensure the system's safe and stable operation.

[0003] In flywheel energy storage devices, the support structure is a key component affecting the energy loss rate. Early flywheels mainly used mechanical bearings for support, but due to unavoidable mechanical wear, they were gradually replaced by magnetic bearing technology. Although magnetic bearing technology solved the mechanical wear problem, it still faces many challenges in practical applications. Especially under high-speed rotation conditions, the flywheel rotor may develop slight eccentricity due to factors such as material inhomogeneity, processing errors, or assembly deviations. This eccentricity leads to increased centrifugal force, which in turn causes problems such as increased vibration and noise, seriously affecting the flywheel's service life and operational safety.

[0004] In existing technologies, such as the flywheel energy storage device disclosed in CN105024479A, although a levitation scheme combining permanent magnet bearings and hybrid magnetic bearings is adopted, its control system lacks the ability to monitor the flywheel eccentricity in real time and cannot dynamically adjust the magnetic levitation force according to the actual eccentricity. This kind of magnetic levitation system with fixed parameters is difficult to effectively cope with the dynamic imbalance problem generated during high-speed rotation, resulting in insufficient system stability and potential safety hazards.

[0005] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0006] The technical problem to be solved by this application is to provide a flywheel energy storage device that effectively avoids dynamic imbalance when the flywheel rotates at high speed, thereby improving the stability and safety of operation.

[0007] The technical solution of this application is: a flywheel energy storage device, including a flywheel with a rotating shaft, a magnetic bearing that provides radial / axial support for the rotating shaft, a vacuum shroud that provides a vacuum working environment for the flywheel, an integrated motor that bidirectionally converts electrical energy and kinetic energy between the flywheel and the electrical equipment, and a control system. The control system includes a displacement sensor that can monitor the flywheel eccentricity in real time, and a connected magnetic levitation controller. The magnetic bearing includes an electromagnetic bearing and / or a permanent magnet bearing. The magnetic levitation controller adjusts the electromagnetic force in the electromagnetic bearing through an algorithm to counteract the centrifugal force caused by the flywheel eccentricity.

[0008] Furthermore, this application proposes that the algorithm is a PID control algorithm.

[0009] Furthermore, this application also proposes that the electromagnetic bearing is a low-temperature superconducting magnetic bearing.

[0010] Furthermore, this application also proposes that the displacement sensor is an eddy current sensor.

[0011] Furthermore, this application also proposes that the integrated motor is a magnetically levitated switched reluctance motor, comprising an inner stator and an outer rotor, with a flywheel nested on the outer rotor.

[0012] Furthermore, this application also proposes that the control system further includes a safety protection unit, a speed sensor, a vibration sensor, a vacuum sensor, and a mechanical braking device. When the safety protection unit detects that the speed exceeds the limit, the vibration is too large, or the vacuum is too low, it triggers the mechanical braking device to stop the flywheel from rotating.

[0013] Furthermore, this application also proposes that the mechanical braking device is a carbon fiber sheath disposed on the edge of the flywheel.

[0014] Furthermore, this application also proposes that the inner surface of the sheath is provided with heat dissipation grooves.

[0015] Furthermore, this application also proposes that the integrated motor connects an oil pump, a hydraulic motor, a transmission, and a permanent magnet generator.

[0016] The technical advantage of this application is that it provides a flywheel energy storage device with real-time eccentricity monitoring and magnetic levitation control. By monitoring the flywheel eccentricity in real time through a displacement sensor and dynamically adjusting the electromagnetic force of the electromagnetic bearing in conjunction with the magnetic levitation controller, the influence of centrifugal force on the flywheel is counteracted, thereby solving the problem of aggravated vibration caused by dynamic imbalance during high-speed rotation. It has the advantages of improving operational stability and safety. Attached Figure Description

[0017] Figure 1 This is a structural diagram provided for this application.

[0018] Figure 2 A functional block diagram provided for this application.

[0019] Figure 3 A connection diagram for another embodiment provided in this application.

[0020] In the diagram: 1-Vacuum chamber; 2-Rotating shaft; 3-Permanent magnet bearing; 4-Flywheel; 5-Integrated motor; 51-Oil pump; 52-Hydraulic motor; 53-Gearbox; 54-Permanent magnet generator; 6-Electromagnetic bearing; 7-Control system; 71-Magnetic levitation controller; 72-Eddy current sensor; 73-Safety protection unit; 74-Speed ​​sensor; 75-Vibration sensor; 76-Vacuum sensor; 77-Mechanical braking device. Implementation

[0021] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0022] See Figures 1-2 This application proposes a flywheel energy storage device, including a flywheel 4 with a shaft 2, a magnetic bearing providing radial or axial support for the shaft, a vacuum chamber 1, an integrated motor 5, and a control system 7. The control system 7 includes a displacement sensor that monitors the flywheel eccentricity in real time and a connected magnetic levitation controller 71. The magnetic bearing includes an electromagnetic bearing 6 or a permanent magnet bearing 3. The magnetic levitation controller 71 adjusts the electromagnetic force of the electromagnetic bearing 6 through an algorithm to counteract the centrifugal force.

[0023] Among them, the magnetic bearing refers to a device that achieves non-contact support through magnetic field force. Specifically, it can adopt a combination structure of electromagnetic coil and permanent magnet. The electromagnetic bearing 6 adjusts the magnetic field strength through current, and the permanent magnet bearing 3 provides the basic support force. The displacement sensor refers to a device that detects the radial offset of the flywheel, such as the eddy current sensor 72, which converts the displacement into an electrical signal through the principle of electromagnetic induction. The magnetic levitation control 71 refers to a processor that outputs adjustment commands based on a control algorithm, such as using a PID algorithm to calculate the electromagnetic force compensation value. The integrated motor refers to an energy conversion device that combines motoring and power generation functions, such as a magnetic levitation switched reluctance motor, whose outer rotor is directly connected to the flywheel to reduce transmission losses.

[0024] Specifically, when the flywheel rotates at high speed, the displacement sensor continuously collects shaft offset data and transmits it to the magnetic levitation controller 71. The controller calculates the current magnitude and direction of the centrifugal force according to a preset algorithm and generates a corresponding current adjustment command. After receiving the command, the electromagnetic bearing 6 changes the coil current intensity to generate an electromagnetic force opposite to the direction of the centrifugal force. The permanent magnet bearing 3 provides static support to reduce electromagnetic adjustment energy consumption, and the vacuum cover 1 eliminates air resistance. The integrated motor 5 operates as a motor when the flywheel accelerates and switches to generator mode when discharging. Its outer rotor is directly nested with the flywheel to ensure energy conversion efficiency. The control system 7 achieves dynamic balance of the flywheel 4 through a closed-loop feedback mechanism to avoid the accumulation of vibration energy.

[0025] Compared to existing technologies, current solutions rely on permanent magnet bearings and fixed-parameter suspension systems, which cannot compensate for eccentricity in real time. This solution, through dynamic adjustment by displacement sensors and a magnetic levitation controller, continuously corrects the support force during flywheel operation, solving the vibration problem caused by eccentricity in traditional structures. Simultaneously, the use of a hybrid electromagnetic and permanent magnet bearing reduces energy consumption while ensuring adjustment accuracy. The direct connection between the integrated motor and flywheel minimizes energy loss in intermediate transmission links.

[0026] Through the above technical solution, this application achieves real-time monitoring and dynamic compensation of eccentricity during flywheel rotation, effectively suppressing vibrations caused by material inhomogeneity or assembly errors, and improving system operational stability. The hybrid electromagnetic and permanent magnet support structure enhances adjustment flexibility while maintaining low energy consumption, and the vacuum environment and direct-connection energy conversion device further reduce overall energy loss.

[0027] This application proposes using a PID control algorithm as the core adjustment method for magnetic levitation control. The PID control algorithm refers to a closed-loop control method comprising three control elements: proportional, integral, and derivative. It can be implemented using a microprocessor or digital signal processor. The proportional element generates a compensation signal proportional to the error amplitude based on the real-time monitored eccentricity error. The integral element eliminates the accumulated steady-state error during system operation, and the derivative element predicts the changing trend of centrifugal force and generates a suppression signal in advance.

[0028] Specifically, the displacement sensor converts the flywheel eccentricity into an electrical signal input to the control unit. The PID algorithm calculates the weighted sum of the proportional, integral, and derivative terms based on the current error value, and outputs dynamically adjusted electromagnetic force control commands. The proportional coefficient determines the system's response speed to instantaneous deviations, the integral time constant controls the rate at which residual deviations are eliminated, and the derivative time constant suppresses overshoot. Through the synergistic effect of these three components, the levitation force generated by the electromagnetic bearing can track the changing trajectory of centrifugal force in real time, forming a negative feedback regulation mechanism.

[0029] Compared to existing technologies, traditional magnetic levitation systems employ fixed-parameter control strategies, making it impossible to dynamically adjust the electromagnetic force based on the actual operating state of the flywheel. This solution, however, utilizes a PID algorithm error feedback mechanism to adapt to dynamic imbalances caused by uneven flywheel materials and installation errors, continuously correcting the levitation force distribution during high-speed rotation.

[0030] Through the above technical solution, this application achieves active suppression of flywheel eccentric vibration, effectively reduces the mechanical vibration amplitude during high-speed rotation, avoids bearing wear and energy loss caused by centrifugal force fluctuations, thereby improving the operational stability and service life of the flywheel system.

[0031] This application proposes that the electromagnetic bearing be a cryogenic superconducting magnetic bearing. Specifically, a cryogenic superconducting magnetic bearing refers to a magnetic levitation support component that uses superconducting materials to operate in a cryogenic environment. This can be achieved by immersing niobium-titanium alloy or yttrium barium copper oxide superconducting materials in a liquid nitrogen or liquid helium cooling environment. At the critical temperature, the resistance of the superconducting material approaches zero, allowing the magnetic field to be maintained without continuous energy input after the coil is energized, thereby reducing operating energy consumption.

[0032] Specifically, cryogenic superconducting magnetic bearings utilize liquid nitrogen or liquid helium cooling systems to lower the temperature of the superconducting coil below the critical point, bringing it into a superconducting state. At this state, the magnetic field strength generated by energizing the coil is significantly higher than that of conventional electromagnetic bearings, and the magnetic field stability is also greater. Because resistance disappears in the superconducting state, current flows continuously in a closed loop without generating Joule heat, avoiding the magnetic force attenuation problem caused by resistance heating in traditional electromagnetic bearings. The magnetic levitation controller precisely controls the magnetic field strength by adjusting the initial input current to the superconducting coil, thereby counteracting the centrifugal force disturbance caused by eccentricity during high-speed flywheel rotation and ensuring the stability of the levitation support.

[0033] Compared to existing technologies, traditional electromagnetic bearings rely on room-temperature conductive materials, resulting in low energy efficiency due to resistance losses during operation. Furthermore, the heat generated by continuous power supply weakens the magnetic field strength, affecting levitation stability. In contrast, cryogenic superconducting magnetic bearings eliminate resistance losses, reducing energy consumption while maintaining a constant magnetic field strength. This solves the problems of magnetic force attenuation and insufficient stability caused by heat generation in traditional solutions.

[0034] Through the above technical solution, this application can significantly reduce the energy consumption of electromagnetic bearings, avoid magnetic field strength fluctuations caused by resistance heating, thereby improving the suspension stability of the flywheel at high speed and extending the service life of the equipment.

[0035] This application proposes a displacement sensor employing an eddy current sensor. An eddy current sensor is a device that achieves non-contact displacement measurement based on the principle of electromagnetic induction. Specifically, it can be implemented by winding a coil on a ceramic substrate and encapsulating it in a high-temperature resistant shell. It infers the displacement by detecting changes in the eddy current field on the surface of the conductor being measured. This sensor can complete measurements without physical contact in a vacuum environment, avoiding the introduction of additional frictional interference. Its high sensitivity characteristic means that the eddy current sensor can detect micrometer-level displacement changes. This can be achieved by optimizing the coil winding density and excitation frequency parameters, with a resolution on the order of 0.1 micrometers, meeting the detection requirements for minute eccentricities of high-speed rotating bodies.

[0036] Specifically, an eddy current sensor is positioned on the inner wall of the vacuum chamber, facing the outer edge of the flywheel. A high-frequency alternating magnetic field induces eddy currents on the flywheel's metal surface. When the flywheel experiences radial displacement due to eccentricity, the change in the distance between the sensor and the flywheel surface alters the eddy current intensity, which is converted into an electrical signal. This signal is filtered, amplified, and transmitted to the magnetic levitation controller. The controller dynamically adjusts the excitation current of the electromagnetic bearing according to a preset algorithm, ensuring that the electromagnetic force counteracts the centrifugal force in real time. Because the eddy current sensor is unaffected by gaseous media in a vacuum environment, and its non-contact nature avoids measurement errors caused by friction in traditional contact sensors, the accuracy of eccentricity monitoring is improved by two orders of magnitude.

[0037] Compared to existing technologies, traditional flywheel energy storage devices mostly use photoelectric encoders or capacitive sensors for displacement detection. The former is susceptible to optical window contamination affecting measurement stability in a vacuum environment, while the latter suffers from short measurement distances and susceptibility to electromagnetic interference. In contrast, the eddy current sensor used in this solution not only adapts to vacuum conditions, but its wide measurement range also covers displacement fluctuations across the entire operating speed range of the flywheel. Furthermore, its electromagnetic shielding design effectively suppresses interference from the motor's magnetic field.

[0038] Through the above technical solution, this application achieves high-precision real-time monitoring of flywheel eccentricity, controls displacement detection error within the micrometer range, improves the accuracy of feedback data of the magnetic levitation control system, effectively suppresses vibration amplification caused by eccentricity detection distortion, reduces the radial amplitude of the flywheel during operation to less than 5% of the original level, and significantly extends the service life of the bearing system.

[0039] This application proposes a flywheel energy storage device employing a magnetically levitated switched reluctance motor as an integrated motor. This motor comprises an inner stator and an outer rotor, with the flywheel nested within the outer rotor. The magnetically levitated switched reluctance motor refers to an energy conversion device that combines magnetic levitation technology with a switched reluctance motor. Specifically, it can utilize contactless electromagnetic force to achieve rotor levitation and drive, for example, by controlling the rotor position through an alternating magnetic field generated by the stator windings. This structure reduces vibration transmission paths by eliminating mechanical contact.

[0040] The inner stator and outer rotor refer to the spatial arrangement of the motor stator located inside the rotor. Specifically, this can involve a ring-shaped stator winding mating with a cylindrical rotor core, for example, fixing the stator to the inner wall of a vacuum chamber while the rotor rotates around its outer side. This arrangement shortens the axial dimension and enhances structural compactness. The flywheel nested on the outer rotor means that the flywheel and motor rotor are coaxially assembled. Specifically, the flywheel can be mounted on the outer circumference of the outer rotor through interference fit or flange connection. For example, a carbon fiber composite flywheel can be combined with an aluminum alloy rotor using a thermal fitting process. This nested structure reduces the accumulation of eccentricity caused by assembly errors.

[0041] Specifically, when the stator windings of the magnetic levitation switched reluctance motor are energized, they generate radial levitation force and tangential driving force, causing the outer rotor to levitate and rotate without contact. The nested assembly of the flywheel and the outer rotor forms a single rotating body, and during rotation, the inertial force of the flywheel directly acts on the levitation control system of the outer rotor. When the flywheel experiences slight eccentricity due to material inhomogeneity, the magnetic levitation system compensates for the centrifugal force offset by adjusting the electromagnetic force in real time, preventing vibration from being transmitted to the vacuum chamber through the mechanical bearings. The layered layout of the inner stator and outer rotor concentrates the electromagnetic action area of ​​the motor within the flywheel's rotation plane, reducing the possibility of axial vibration mode excitation.

[0042] Compared to existing technologies, in CN105024479A, the flywheel is separately connected to the motor rotor via a shaft. The assembly gap between the shaft and flywheel can easily lead to the accumulation of eccentric errors. Furthermore, the levitation control and drive functions of a single-winding external rotor magnetic levitation motor share the same winding, posing a risk of electromagnetic interference. This solution eliminates assembly errors in the shaft connection through a nested integrated design of the flywheel and motor rotor. Simultaneously, it integrates the levitation control and drive functions into the independent winding of the magnetic levitation switched reluctance motor, achieving decoupled control.

[0043] Through the above technical solution, this application effectively suppresses the eccentric vibration caused by assembly errors or material defects when the flywheel rotates at high speed. It blocks the vibration transmission path through non-contact magnetic levitation control and integrated rotating body structure, while optimizing the spatial layout of the energy conversion system and improving the dynamic stability and operational reliability of the system.

[0044] This application proposes a control system that also includes a safety protection unit 73, a speed sensor 74, a vibration sensor 75, a vacuum sensor 76, and a mechanical braking device 77. When the safety protection unit 73 detects excessive speed, excessive vibration, or insufficient vacuum, it triggers the mechanical braking device 77 to stop the flywheel's rotation. The safety protection unit 73 is a control module for receiving and processing sensor signals, which can be implemented using an embedded microprocessor. It determines whether to trigger braking action based on preset logic. The speed sensor 74 is a device for real-time detection of the flywheel's rotational speed, which can be implemented using a Hall effect sensor to monitor whether the flywheel exceeds its rated speed range. The vibration sensor 75 is a device for acquiring mechanical vibration signals from the flywheel, which can be implemented using a piezoelectric accelerometer to identify abnormal vibration patterns. The vacuum sensor 76 is an element for measuring the air pressure inside the vacuum chamber, which can be implemented using a capacitive vacuum gauge to determine whether the vacuum level is below the minimum threshold required to maintain low-loss operation of the flywheel. The mechanical braking device 77 is a mechanism that achieves flywheel braking through physical contact and frictional resistance, which can be implemented using an electromagnetically driven brake caliper, enabling rapid response to braking commands in emergency situations.

[0045] Specifically, the safety protection unit 73 continuously receives speed data from the speed sensor 74, vibration amplitude data from the vibration sensor 75, and pressure data from the vacuum sensor 76. When the speed data exceeds a preset safety threshold, it indicates that the flywheel is at risk of overspeed; when the vibration amplitude exceeds the allowable range, it indicates that the flywheel may resonate due to eccentricity or structural damage; when the pressure data is higher than a critical value, it indicates that the vacuum environment has failed, leading to a sharp increase in air friction loss. The safety protection unit 73 processes the three sensor signals in parallel and immediately sends a trigger signal to the mechanical braking device 77 when any abnormal condition is met. After receiving the signal, the mechanical braking device 77 drives the actuator to contact the edge of the flywheel, consuming the flywheel's kinetic energy through friction until it comes to a complete stop. This multi-parameter independent monitoring and linkage response mechanism ensures rapid braking intervention under any single fault mode.

[0046] Compared to existing technologies, traditional flywheel energy storage devices typically only utilize a single type of fault detection sensor, such as monitoring only rotational speed or vibration parameters, and their braking response relies on a gradually decelerating motor braking method. When a sudden drop in vacuum or a complex fault occurs, a single sensor cannot comprehensively identify the risk, and the motor braking response delay can lead to braking failure. This solution adds a vacuum monitoring channel, forming a triple-redundant monitoring network with rotational speed and vibration parameters. Simultaneously, it employs a mechanical braking device as an emergency braking unit independent of the motor system, capable of cutting off flywheel kinetic energy within milliseconds, effectively preventing cascading system damage caused by multi-factor coupled faults.

[0047] Through the above technical solutions, this application can immediately implement forced braking when the flywheel speed exceeds the mechanical structure's tolerance limit, preventing shaft deformation or bearing overheating failure; promptly terminate rotation when the flywheel vibrates violently due to mass eccentricity, avoiding resonance that could lead to flywheel disintegration; and quickly shut down the machine when a leak in the vacuum chamber causes an increase in internal air pressure, preventing high temperatures from air friction that could burn out the motor windings. This multi-dimensional abnormal state identification and rapid braking mechanism significantly reduces the risk of failure and loss of the flywheel energy storage device under extreme operating conditions.

[0048] This application proposes a mechanical braking device as a carbon fiber sheath disposed at the edge of the flywheel. The carbon fiber sheath refers to a ring-shaped wrapping structure made of carbon fiber composite material, specifically achieved using a prepreg molding process. Its high specific strength and high thermal conductivity can withstand the mechanical load and heat generated by braking friction. Distributing it at the edge of the flywheel means that the sheath maintains a preset gap with the outer circumference of the flywheel. When braking is triggered, the sheath moves radially to contact the outer edge of the flywheel, maximizing the braking contact area. The mechanical braking device is an actuator that dissipates the kinetic energy of the flywheel through friction. When the carbon fiber sheath contacts the flywheel, it generates a uniformly distributed frictional torque, preventing material failure due to localized overheating.

[0049] Specifically, when the safety protection unit detects excessive speed or abnormal vacuum, the carbon fiber sheath moves radially until it contacts the outer edge of the flywheel. Because the sheath completely encloses the outer circumference of the flywheel, the braking friction is evenly distributed along the circumference, effectively eliminating stress concentration caused by single-point contact. The carbon fiber material maintains a stable coefficient of friction even at high temperatures, ensuring linear torque decay during braking. The sheath's annular structure forms continuous constraints during braking, suppressing the transmission of lateral vibrations caused by flywheel eccentricity to the magnetic bearing.

[0050] Compared to existing technologies, traditional mechanical braking devices often use metal brake pads that contact the flywheel end face, which can easily lead to uneven contact pressure distribution due to end face deformation during braking. Carbon fiber sheaths, through a full-circumferential contact mode on the outer circumference, eliminate the impact of axial runout on braking stability. Compared to metal materials, the lightweight properties of carbon fiber reduce the inertia of the braking device and shorten the response time.

[0051] Through the above technical solution, this application can achieve rapid braking when the flywheel operates abnormally. The braking force is evenly distributed through a full-circumferential contact mode on the outer circumference, preventing damage to the flywheel surface. The high-temperature resistance of carbon fiber material maintains stability during the braking process, while the annular sheath structure simultaneously suppresses vibration transmission, preventing impact damage to precision components such as magnetic bearings.

[0052] In some specific embodiments, staggered heat dissipation grooves can be machined on the inner surface of the carbon fiber sheath. The groove depth is controlled within the range of 1-3 mm, and the grooves are filled with boron nitride powder as a solid lubricant. This design reduces friction interface wear while ensuring braking force, thus extending the service life of the sheath.

[0053] See Figure 3 In another embodiment of this application, the integrated motor 5 is further connected to electrical equipment, including an oil pump 51, a hydraulic motor 52, a gearbox 53, and a permanent magnet generator 54. Its output electrical energy starts the oil pump, which drives the hydraulic motor, which in turn connects the gearbox to the permanent magnet generator to generate electricity, thereby improving power generation efficiency.

[0054] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A flywheel energy storage device, comprising a flywheel with a shaft, a magnetic bearing providing radial / axial support for the shaft, a vacuum chamber providing a vacuum working environment for the flywheel, an integrated motor for bidirectional conversion of electrical energy and kinetic energy between the flywheel and electrical equipment, and a control system, characterized in that: The control system includes a displacement sensor that can monitor the flywheel eccentricity in real time, and a connected magnetic levitation controller. The magnetic bearing includes an electromagnetic bearing and / or a permanent magnet bearing. The magnetic levitation controller adjusts the electromagnetic force in the electromagnetic bearing through an algorithm to counteract the centrifugal force caused by the flywheel eccentricity.

2. The flywheel energy storage device as described in claim 1, characterized in that: The algorithm is a PID control algorithm.

3. The flywheel energy storage device as described in claim 1, characterized in that: The electromagnetic bearing is a low-temperature superconducting magnetic bearing.

4. The flywheel energy storage device as described in claim 1, characterized in that: The displacement sensor is an eddy current sensor.

5. The flywheel energy storage device as described in claim 1, characterized in that: The integrated motor is a magnetic levitation switched reluctance motor, which includes an inner stator and an outer rotor, with the flywheel nested on the outer rotor.

6. The flywheel energy storage device as described in claim 1, characterized in that: The control system also includes a safety protection unit, a speed sensor, a vibration sensor, a vacuum sensor, and a mechanical braking device. When the safety protection unit detects that the speed exceeds the limit, the vibration is too large, or the vacuum is too low, it triggers the mechanical braking device to stop the flywheel from rotating.

7. The flywheel energy storage device as described in claim 6, characterized in that: The mechanical braking device is an annular carbon fiber sheath located on the edge of the flywheel.

8. The flywheel energy storage device as described in claim 7, characterized in that: The inner surface of the sheath is provided with heat dissipation grooves.

9. The flywheel energy storage device as described in claim 1, characterized in that: The integrated motor connects the oil pump, hydraulic motor, transmission, and permanent magnet generator.

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