Flywheel rotor running state monitoring method, flywheel energy storage system and storage medium

Abstract

The invention provides a flywheel rotor operation state monitoring method, a flywheel energy storage system and a storage medium, and relates to the technical field of flywheel energy storage. The method comprises the following steps: acquiring a first rotating speed of a flywheel rotor at a first moment and a second rotating speed at a second moment in a free sliding state; wherein the first rotating speed is higher than the second rotating speed, and the first moment is earlier than the second moment; and determining the running state of the flywheel rotor according to the first rotating speed, the first moment, the second rotating speed and the second moment. The running state of the flywheel rotor can be monitored, abnormity of the flywheel rotor can be found in time, safe and reliable running of the flywheel is guaranteed, and then the effect that the flywheel participates in primary frequency modulation is guaranteed.

Description

Technical Field

[0001] This application relates to the field of flywheel energy storage technology, and in particular to a method for monitoring the operating status of a flywheel rotor, a flywheel energy storage system, and a storage medium. Background Technology

[0002] Magnetic levitation flywheels are energy storage devices supported by magnetic bearings. Compared to traditional mechanical bearings, the magnetic bearings that support the flywheel's rotation reduce mechanical friction, significantly improving energy storage efficiency and lifespan, giving magnetic levitation flywheels a unique position in the energy storage field. Specifically, magnetic levitation flywheels can be used as energy storage devices in primary frequency regulation of power systems to improve grid stability.

[0003] In a magnetic levitation flywheel, kinetic energy storage and release are achieved through the rotation of the flywheel rotor. During energy storage, external electrical energy drives a motor, accelerating the flywheel rotor and converting electrical energy into kinetic energy for storage. During energy release, the high-speed rotating flywheel drives a motor to generate electricity, converting kinetic energy back into electrical energy for release and supplying it to the load. Furthermore, when the flywheel is detached from the motor and load and maintains its rotation solely due to its own inertia (i.e., in a free-gliding state), its rotational kinetic energy decreases only due to various inherent losses. The flywheel rotor plays a crucial role in energy storage, energy release, and free-gliding. Abnormal vibrations or positional deviations in the flywheel rotor can affect its operational safety and reliability, consequently impacting the effectiveness of primary frequency regulation. Therefore, accurate monitoring of the flywheel rotor's operating status is essential. Summary of the Invention

[0004] This application provides a method for monitoring the operating status of a flywheel rotor, a flywheel energy storage system, and a storage medium to monitor the operating status of the flywheel rotor, detect abnormalities in the flywheel rotor in a timely manner, and ensure the safe and reliable operation of the flywheel.

[0005] In a first aspect, embodiments of this application provide a method for monitoring the operating status of a flywheel rotor, including: The first rotational speed of the flywheel rotor in free-gliding state is obtained at a first moment and a second rotational speed at a second moment; wherein the first rotational speed is greater than the second rotational speed, and the first moment is earlier than the second moment; The operating state of the flywheel rotor is determined based on the first rotational speed, the first time, the second rotational speed, and the second time.

[0006] In one possible implementation, determining the operating state of the flywheel rotor based on the first rotational speed, the first moment, the second rotational speed, and the second moment includes: Based on the first rotational speed, the first moment, the second rotational speed, and the second moment, determine the power loss value of the flywheel rotor in the free-gliding state; The operating state of the flywheel rotor is determined based on the power loss value.

[0007] In one possible implementation, determining the power loss value of the flywheel rotor in the free-slip state based on the first rotational speed, the first moment, the second rotational speed, and the second moment includes: Based on the first rotational speed and the moment of inertia of the flywheel rotor, the first rotational kinetic energy of the flywheel rotor at the first moment is determined; The second rotational kinetic energy of the flywheel rotor at the second moment is determined based on the second rotational speed and the moment of inertia. The power loss value of the flywheel rotor in free-gliding state is determined based on the first rotational kinetic energy, the second rotational kinetic energy, the first moment, and the second moment.

[0008] In one possible implementation, determining the operating state of the flywheel rotor based on the power loss value includes: Detect whether the power loss value is greater than a preset power loss threshold; If the power loss value is greater than the power loss threshold, then the operating state of the flywheel rotor is determined to be abnormal. If the power loss value is less than or equal to the power loss threshold, then the flywheel rotor is determined to be in normal operating condition.

[0009] In one possible implementation, determining the operating state of the flywheel rotor based on the first rotational speed, the first moment, the second rotational speed, and the second moment includes: Based on the first moment and the second moment, determine the duration of the flywheel rotor's change from the first speed to the second speed; The standard duration of the flywheel rotor speed change is determined based on the first speed and the second speed. The operating state of the flywheel rotor is determined based on the change duration and the standard duration.

[0010] In one possible implementation, determining the operating state of the flywheel rotor based on the variation duration and the standard duration includes: If the duration of the change is greater than or equal to the standard duration, then the operating state of the flywheel rotor is determined to be normal. If the duration of the change is less than the standard duration, then the operating state of the flywheel rotor is determined to be abnormal.

[0011] In one possible implementation, after determining that the flywheel rotor's operating state is abnormal, the method further includes: Obtain the vacuum level of the vacuum chamber corresponding to the flywheel rotor in the free-gliding state; If the vacuum level is greater than the preset vacuum level, it is determined that the flywheel rotor has abnormal wind resistance loss. If the vacuum degree is less than or equal to the preset vacuum degree, then based on the rotational speed data of multiple times from the first time to the second time obtained in advance, the rotational speed change curve of the flywheel rotor from the first time to the second time is obtained; Based on the speed change rate curve and the preset change rate curve, a difference curve is determined; wherein, the preset change rate curve is the speed change rate curve of the flywheel rotor under normal operating conditions; If the difference curve is linearly related to the rotational speed of the flywheel rotor, then it is determined that the flywheel rotor has abnormal bearing wear. If the difference curve is linearly related to the square of the rotational speed of the flywheel rotor, then it is determined that the flywheel rotor has abnormal eddy current losses.

[0012] In one possible implementation, after determining that the flywheel rotor's operating state is abnormal, the method further includes: Acquire temperature data from the first moment to the second moment at multiple locations in the flywheel energy storage system where the flywheel rotor is located; Based on the temperature data, the temperature change rate at multiple locations of the flywheel energy storage system is determined; The abnormal locations of the flywheel energy storage system are determined based on the temperature change rate at each location and the corresponding preset temperature change threshold.

[0013] Secondly, embodiments of this application provide a flywheel rotor operating status monitoring device, comprising: The acquisition module is used to acquire the first rotational speed of the flywheel rotor at a first moment and the second rotational speed at a second moment in a free-gliding state; wherein the first rotational speed is greater than the second rotational speed, and the first moment is earlier than the second moment; The determination module is used to determine the operating state of the flywheel rotor based on the first rotational speed, the first time, the second rotational speed, and the second time.

[0014] Thirdly, embodiments of the present invention provide a flywheel energy storage system, including a flywheel rotor, a speed measuring device, a timing device, and a monitoring device, wherein the monitoring device is used to implement the method in the first aspect or any possible implementation of the first aspect.

[0015] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described in the first aspect or any possible implementation thereof.

[0016] Fifthly, embodiments of the present invention provide a computer program product, including a computer program that, when executed by a processor, implements the method described in the first aspect or any possible implementation thereof.

[0017] The beneficial effects of the embodiments in this application compared with the prior art are: This application embodiment obtains the first rotational speed of the flywheel rotor at the first moment and the second rotational speed at the second moment during free gliding, thereby obtaining relevant data on energy loss of the flywheel rotor. By using the first rotational speed, the first moment, the second rotational speed, and the second moment when the flywheel rotor experiences energy loss, the specific energy loss situation of the flywheel rotor can be clearly identified, thereby determining whether there is abnormal energy loss in the flywheel rotor, quickly and accurately obtaining the operating status of the flywheel rotor, timely detecting abnormalities in the flywheel rotor, ensuring the safe and reliable operation of the flywheel, and thus ensuring the effectiveness of the primary frequency regulation involving the flywheel. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating the implementation of the flywheel rotor operating status monitoring method provided in this application embodiment; Figure 2 This is a schematic diagram of the flywheel rotor operating status monitoring device provided in the embodiments of this application; Figure 3 This is a schematic diagram of the flywheel energy storage system provided in the embodiments of this application. Detailed Implementation

[0020] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0021] Flywheel rotors store, release, and conserve energy through rotation. Abnormal vibrations or positional misalignments in the flywheel rotor increase energy loss, affecting its reliability and safety. Therefore, accurate monitoring of the flywheel rotor's operating status is crucial for timely detection of any abnormalities.

[0022] Considering that the flywheel experiences eddy current losses, bearing losses, and wind resistance losses during free-gliding, which affect its rotational energy and cause a decrease in the flywheel rotor's speed (i.e., energy loss), this application's embodiment obtains the flywheel rotor's operating data during free-gliding by acquiring its first rotational speed at a first moment and its second rotational speed at a second moment. This operating data clarifies the specific energy loss of the flywheel rotor, allowing for the determination of any abnormal energy loss and rapid, accurate determination of its operating status to ensure safe flywheel operation.

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the following description will be provided in conjunction with the accompanying drawings and specific embodiments.

[0024] A flywheel energy storage system mainly consists of a main shaft, a flywheel rotor, a motor, magnetic levitation bearings, and a sealed housing. The flywheel rotor is mounted on the main shaft and stores energy in the form of kinetic energy through rotation. The motor can be an induction motor, a reluctance motor, or a permanent magnet motor. Taking a permanent magnet motor as an example, it can function as both a motor and a generator. The motor rotor has embedded permanent magnets, and the motor rotor and flywheel rotor are mounted on the main shaft and rotate synchronously. During energy storage, the motor drives the flywheel rotor to accelerate; during energy release, the high-speed rotating flywheel drives the motor rotor to rotate, generating electricity. A magnetic radial bearing is installed above the main shaft, and magnetic radial and axial bearings are installed below the main shaft. The axial bearing supports the mass of the flywheel rotor and the motor rotor, while the radial bearing ensures that the main shaft remains on its central axis. The sealed housing serves as the base and outer shell of the flywheel energy storage system. The sealed housing provides a vacuum environment for the flywheel rotor, reducing air resistance during its rotation.

[0025] Figure 1 The implementation flowchart of the flywheel rotor operating status monitoring method provided in the embodiments of the present invention is described in detail below: Step 101: Obtain the first rotational speed of the flywheel rotor at the first moment and the second rotational speed at the second moment in the free-gliding state; wherein the first rotational speed is greater than the second rotational speed and the first moment is earlier than the second moment.

[0026] In this embodiment, the free-gliding state refers to the state in which the flywheel rotor is disconnected from the motor drive and load consumption, without external interference, and maintains rotation solely by its own inertia.

[0027] By collecting the first rotational speed at the first moment and the second rotational speed at the second moment of the flywheel rotor in free-gliding state, the rotational speed change data of the flywheel rotor can be obtained, thereby analyzing the operating state of the flywheel rotor.

[0028] During free-gliding, losses also occur, such as eddy current losses, bearing losses, and wind resistance losses, causing the flywheel rotor speed to gradually decrease over time. Therefore, the first speed at the earliest moment (the first instant) is greater than the second speed at the latest moment (the second instant).

[0029] Here, a first speed and a second speed can be predetermined. Timing starts from a first moment corresponding to the first speed, and a second moment corresponding to the second speed is obtained, thus yielding the first speed, the second speed, the first moment, and the second moment that can be used to calculate power loss values. Alternatively, the first moment and the second moment can be predetermined, and the first speed corresponding to the first moment and the second speed corresponding to the second moment can be obtained.

[0030] Furthermore, the speed difference between the first and second speeds can be predetermined, or the time difference between the first and second moments can be predetermined. When the speed difference is predetermined, the current moment can be taken as the first moment, the speed corresponding to the current moment as the first speed, and the corresponding second speed can be obtained according to the speed difference, and the second moment corresponding to the second speed can be determined by timing. Similarly, when the time difference is predetermined, the current moment can be taken as the first moment, the speed corresponding to the current moment as the first speed, and the corresponding second moment can be obtained according to the time difference, and the second speed corresponding to the second moment can be acquired. The current moment can also be any desired moment, selected based on the flywheel rotor's operating conditions.

[0031] Step 102: Determine the operating state of the flywheel rotor based on the first rotational speed, the first moment, the second rotational speed, and the second moment.

[0032] In this embodiment, by acquiring the rotational speed at different times, the rotational speed change of the flywheel rotor can be obtained, thereby determining whether there is abnormal energy loss in the flywheel rotor and whether the operating state of the flywheel rotor is abnormal.

[0033] This application embodiment obtains the first rotational speed of the flywheel rotor at a first moment and the second rotational speed at a second moment during free-gliding, thus acquiring relevant data on energy loss in the flywheel rotor. By using the first rotational speed, the first moment, the second rotational speed, and the second moment when energy loss occurs, the specific energy loss situation of the flywheel rotor can be clearly identified, thereby determining whether there is abnormal energy loss in the flywheel rotor. This allows for rapid and accurate determination of the flywheel rotor's operating status, timely detection of flywheel rotor anomalies, and ensures the safe and reliable operation of the flywheel, thereby guaranteeing the effectiveness of primary frequency regulation involving the flywheel. Furthermore, the flywheel rotor operating status monitoring method provided in this application embodiment is primarily applied to flywheel energy storage systems, and is not limited to flywheel energy storage systems used in primary frequency regulation.

[0034] In some embodiments, determining the operating state of the flywheel rotor based on the first rotational speed, the first moment, the second rotational speed, and the second moment can be achieved by determining the power loss value of the flywheel rotor in a free-gliding state based on the first rotational speed, the first moment, the second rotational speed, and the second moment, and then determining the operating state of the flywheel rotor based on the power loss value.

[0035] In this embodiment, considering that the decrease in the speed of the flywheel rotor in the free-gliding state is only caused by its own energy loss, the power loss value of the flywheel rotor is determined by the speed of the flywheel rotor at two different times, that is, the energy loss of the flywheel rotor between the two times can be obtained, which can directly reflect the energy consumption intensity of the rotor.

[0036] By analyzing the obtained power loss values, it can be determined whether there is abnormal energy loss in the flywheel rotor during operation, thus obtaining the operating status of the flywheel rotor.

[0037] Here, by converting the change in the speed of the flywheel rotor into a quantifiable loss value, the operating status of the flywheel rotor can be accurately judged, and abnormal operating status of the flywheel energy storage system can be detected in a timely manner.

[0038] Optionally, the power loss value of the flywheel rotor in the free-gliding state can be determined based on the first rotational speed, the first moment, the second rotational speed, and the second moment. This can be achieved by first determining the first rotational kinetic energy of the flywheel rotor at the first moment based on the first rotational speed and the moment of inertia; determining the second rotational kinetic energy of the flywheel rotor at the second moment based on the second rotational speed and the moment of inertia; and then determining the power loss value of the flywheel rotor in the free-gliding state based on the first rotational kinetic energy, the second rotational kinetic energy, the first moment, and the second moment.

[0039] In this embodiment, considering that the flywheel rotor stores energy through rotation, that is, the rotational kinetic energy of the flywheel rotor is actually the energy stored in the flywheel rotor, the rotational kinetic energy of the flywheel rotor at the first and second moments can be calculated by the first and second rotational speeds of the flywheel rotor, so as to obtain the energy change of the flywheel rotor.

[0040] Here, the formula for rotational kinetic energy can be used for calculation. In the formula, Represents rotational kinetic energy. Indicates the moment of inertia. It represents angular velocity.

[0041] The moment of inertia of the flywheel rotor can be obtained from its mass and radius. Taking a cylindrical or disc-shaped flywheel rotor as an example, the moment of inertia can be... In the formula, Indicates the mass of the flywheel rotor. This represents the radius of the flywheel rotor. The angular velocity of the flywheel rotor can be obtained from its rotational speed. In the formula, Indicates angular velocity. Indicates rotational speed.

[0042] Correspondingly, the difference between the first rotational kinetic energy and the second rotational kinetic energy is the energy lost by the flywheel rotor in free-gliding state from the first moment to the second moment, which is also the kinetic energy loss value. By using the duration between the first moment and the second moment, the kinetic energy loss value can be evenly distributed within this duration to obtain the average loss per unit time, which is the power loss value.

[0043] Optionally, the operating status of the flywheel rotor can be determined based on the power loss value. This can be done by detecting whether the power loss value is greater than a preset power loss threshold. If the power loss value is greater than the power loss threshold, the operating status of the flywheel rotor is determined to be abnormal. If the power loss value is less than or equal to the power loss threshold, the operating status of the flywheel rotor is determined to be normal.

[0044] In this embodiment, the flywheel rotor in normal operation will have a reasonable loss range in free gliding state, namely the power loss threshold. When the actual power loss value exceeds the power loss threshold, it indicates that the flywheel rotor has abnormal losses, such as a decrease in vacuum leading to a surge in wind resistance, or magnetic field distortion leading to abnormal eddy currents.

[0045] The preset power loss threshold can be the maximum power loss value during normal operation, calibrated through experiments, simulations, or long-term operating data during the flywheel rotor design or commissioning phase. It can include normal wind resistance loss, normal eddy current loss, and normal bearing loss.

[0046] In other embodiments, the operating state of the flywheel rotor can be determined based on a fixed time interval or a fixed speed difference, as detailed below.

[0047] Based on a fixed time interval, the operating state of the flywheel rotor is determined according to the first rotational speed, the first moment, the second rotational speed, and the second moment. Alternatively, the kinetic energy loss value of the flywheel rotor in free gliding state from the first moment to the second moment can be determined according to the first rotational speed and the second rotational speed. The time interval between the first moment and the second moment is a preset time interval. Then, the operating state of the flywheel rotor is determined according to the kinetic energy loss value.

[0048] In this embodiment, the kinetic energy loss value of the flywheel rotor, calculated directly using the first and second rotational speeds, is used to determine the operating state of the flywheel rotor. The calculation of the kinetic energy loss value can be referred to the description in the above embodiments, and will not be repeated here.

[0049] When determining the operating state of a flywheel rotor, since the duration of its free-glide operation is fixed (i.e., the time interval between the first and second moments is fixed), the maximum kinetic energy loss (i.e., the kinetic energy loss threshold) for each first rotational speed during normal operation is fixed. Therefore, the corresponding kinetic energy loss threshold can be determined based on the first rotational speed. Specifically, the higher the first rotational speed of the flywheel rotor at the first moment, the greater the corresponding kinetic energy loss; there is a mathematical mapping relationship between the first rotational speed and the kinetic energy loss threshold. If the calculated kinetic energy loss value is greater than the corresponding kinetic energy loss threshold, the flywheel rotor's operating state can be determined to be abnormal; if the calculated kinetic energy loss value is less than or equal to the corresponding kinetic energy loss threshold, the flywheel rotor's operating state can be determined to be normal. The kinetic energy loss threshold is determined based on the first rotational speed.

[0050] Here, the kinetic energy loss value of the flywheel rotor is calculated by using the first rotational speed of the flywheel rotor to determine its first kinetic energy at the first moment, and by using its second rotational speed to determine its second kinetic energy at the second moment; the result is obtained by combining the first and second kinetic energies. Therefore, based on a fixed time interval, the operating state of the flywheel rotor can also be directly determined using its second rotational speed at the second moment.

[0051] For each first rotational speed, the maximum kinetic energy loss is fixed, meaning the minimum rotational speed of the flywheel rotor at the second moment is fixed. Therefore, a corresponding loss speed threshold can be determined based on the first rotational speed. This loss speed is the minimum rotational speed of the flywheel rotor when it moves from the first moment to the second moment in free-gliding mode. In other words, there is a mathematical mapping relationship between the first rotational speed and the loss speed threshold. Accordingly, when using the second rotational speed to determine the operating state of the flywheel rotor, the loss speed threshold used is also determined based on the first rotational speed.

[0052] If the second rotational speed of the flywheel rotor at the second moment is greater than or equal to the corresponding loss speed threshold, then the flywheel rotor's operating state can be determined to be normal. If the second rotational speed of the flywheel rotor at the second moment is less than the corresponding loss speed threshold, then the flywheel rotor's operating state can be determined to be abnormal.

[0053] The aforementioned kinetic energy loss threshold and loss speed threshold can be obtained by conducting an operation test on a flywheel rotor in a normal operating state under free sliding conditions.

[0054] Similarly, when determining the operating state of the flywheel rotor using power loss values, it is also based on a fixed time interval or a fixed speed difference. With a fixed time interval, each first speed corresponds to a kinetic energy loss threshold. Correspondingly, when the time interval between the first and second moments is a fixed preset time interval, each first speed also corresponds to a fixed power loss threshold. The higher the first speed of the flywheel rotor at the first moment, the greater the corresponding power loss. That is, there is a mathematical mapping relationship between the first speed and the power loss threshold. The power loss threshold used when judging the operating state of the flywheel rotor is also determined based on the first speed.

[0055] Therefore, the mathematical mapping relationship between the first rotational speed and the aforementioned power loss threshold, kinetic energy loss threshold, and loss speed threshold can be obtained by conducting a series of operating tests on a flywheel rotor in a normal operating state under free-slip conditions.

[0056] This test was conducted on a flywheel rotor in normal operating condition, and the operating environment of the flywheel rotor during the test was the same as that of the flywheel rotor in actual operation. Due to possible deviations during the test, the flywheel rotor was tested multiple times, and the data with the highest loss in the test was selected to determine the threshold.

[0057] Based on a fixed time interval, the time interval selected during the experiment is the same as the time interval during the actual monitoring of the flywheel rotor, i.e., the preset time interval between the first moment and the second moment. The specific experimental procedure is as follows: Step 1: Select multiple speeds from the operating speed range of the flywheel rotor as the initial speeds for the flywheel rotor during the test in the free-slip state (corresponding to the first speed in the above embodiment).

[0058] You can start from the upper limit of the operating speed range and select an initial speed at fixed speed differences until you reach the lower limit of the operating speed range. For example, if the upper limit of the flywheel rotor's operating speed range is 36,000 rpm, the fixed speed difference can be set to 1,200 rpm, and the initial speed can be 36,000 rpm, 34,800 rpm, 33,600 rpm, 32,400 rpm, 31,200 rpm, or 30,000 rpm, etc.

[0059] Step two: Perform a running test on the flywheel rotor in a free-slip state. When running, start timing at the selected initial speed. When the time reaches the preset time interval, obtain the speed at this time as the end speed (corresponding to the second speed in the above embodiment).

[0060] Taking an initial speed of 36,000 rpm and a preset time interval of 300 seconds as an example, the motor in the flywheel system is started to drive the flywheel rotor to speed up to 36,000 rpm and maintain a stable speed at that speed. The motor is then disconnected, allowing the flywheel rotor to enter a free-slip state, and timing begins simultaneously. The speed of the flywheel rotor at 300 seconds is obtained, and this speed is the final speed obtained in this experiment.

[0061] The above experiment was repeated multiple times. The initial speed was 36,000 rpm and the preset time interval was 300 s. A final speed could be obtained for each experiment.

[0062] To ensure the accuracy and comprehensiveness of the data, the experiment can be repeated multiple times for each initial speed, such as 100 times, in order to obtain the minimum final speed of the flywheel rotor under normal conditions from the experiment.

[0063] Step 3: For each initial speed, select the minimum ending speed from the multiple tests and use it as the loss speed threshold for that initial speed.

[0064] For an initial speed of 36,000 rpm, the minimum ending speed obtained from multiple tests at 36,000 rpm is selected as the loss speed threshold for an initial speed of 36,000 rpm.

[0065] Using the above method, a loss speed threshold can be selected for each initial speed. That is, for initial speeds of 34800rpm, 33600rpm, 32400rpm, 31200rpm, and 30000rpm, a loss speed threshold can be selected for each.

[0066] Step four: Using the selected initial rotational speed as the independent variable and the loss rotational speed threshold of each initial rotational speed as the dependent variable, perform mathematical fitting to obtain the mathematical mapping relationship between the initial rotational speed and the loss rotational speed threshold, that is, the mathematical mapping relationship between the first rotational speed and the loss rotational speed threshold.

[0067] In addition, the determination of the kinetic energy loss threshold and the power loss threshold also includes the following process: Step 5, using the kinetic energy formula It can calculate the kinetic energy loss of the flywheel rotor as it drops from the initial speed to the loss speed threshold, and obtain the kinetic energy loss threshold corresponding to each initial speed.

[0068] With an initial speed of 36000 rpm = 1200 Taking rad / s as an example, substituting the initial speed and the moment of inertia of the flywheel rotor into the above kinetic energy formula, the initial kinetic energy of the flywheel rotor at the initial speed can be calculated. Substituting the loss speed threshold and the moment of inertia into the above kinetic energy formula, the final kinetic energy of the flywheel rotor at the loss speed threshold can be calculated, thus obtaining the kinetic energy loss of the flywheel rotor from 36000 rpm to the loss speed threshold. That is, the kinetic energy loss threshold at the initial speed of 36000 rpm is obtained.

[0069] Using the above method, the kinetic energy loss threshold for each initial rotational speed can be calculated.

[0070] Step six: Using the selected initial rotational speed as the independent variable and the kinetic energy loss threshold of each initial rotational speed as the dependent variable, perform mathematical fitting to obtain the mathematical mapping relationship between the initial rotational speed and the kinetic energy loss threshold, that is, the mathematical mapping relationship between the first rotational speed and the loss rotational speed threshold.

[0071] Step seven: Calculate the ratio between the kinetic energy loss threshold and the preset time interval selected during the test to obtain the power loss threshold for each initial rotational speed.

[0072] Taking an initial speed of 36,000 rpm and a preset time interval of 300 s as an example, the power loss threshold can be calculated by dividing the kinetic energy loss threshold of the flywheel rotor by the preset time interval of 300 s.

[0073] Using the above method, the kinetic energy loss threshold for each initial rotational speed can be calculated.

[0074] Step 8: Using the selected initial rotational speed as the independent variable and the power loss threshold of each initial rotational speed as the dependent variable, perform mathematical fitting to obtain the mathematical mapping relationship between the initial rotational speed and the power loss threshold, which is the first type of mathematical mapping relationship between the first rotational speed and the power loss threshold.

[0075] Alternatively, instead of fitting a mathematical mapping relationship, monitoring can be performed using only the loss speed threshold, kinetic energy loss threshold, and power loss threshold obtained during the experiment. Specifically: During the flywheel rotor operation status monitoring process, the initial speed of the flywheel rotor is the initial speed selected in the above-mentioned test, such as 30200 rpm. The selected initial speed includes 30000 rpm. The flywheel rotor speed can be monitored. When the flywheel rotor speed reaches 30000 rpm, this moment is the first moment, and 30000 rpm is the first speed. A preset time interval is then recorded, and the moment the timing ends is the second moment. The speed of the flywheel rotor at the second moment is the second speed. The kinetic energy loss value and power loss value are then calculated. The second speed is compared with the loss speed threshold corresponding to 30000 rpm, or the kinetic energy loss value is compared with the kinetic energy loss threshold corresponding to 30000 rpm, or the power loss value is compared with the power loss threshold corresponding to 30000 rpm, to determine the operating status of the flywheel rotor.

[0076] The above embodiments illustrate the monitoring of the flywheel rotor's operating status and the determination of corresponding thresholds based on fixed time intervals. In addition, the operating status monitoring of the flywheel rotor can also be performed based on a fixed speed difference, as detailed below.

[0077] In other embodiments, based on a fixed speed difference, the operating state of the flywheel rotor is determined according to a first speed, a first moment, a second speed, and a second moment. This can be achieved by first determining the duration of the flywheel rotor's speed change from the first speed to the second speed based on the first and second moments; then determining the standard duration of the flywheel rotor's speed change based on the first and second speeds; and finally determining the operating state of the flywheel rotor based on the change duration and the standard duration.

[0078] In this embodiment, in addition to comparing the kinetic energy loss in the above embodiments to obtain the operating state of the flywheel rotor, the duration can also be directly compared. By using the duration of the change in the flywheel rotor's speed, the rate of speed decrease can be determined, thereby reflecting the intensity of the loss.

[0079] Here, the first and second rotational speeds can be predetermined, or the difference between the first and second rotational speeds can be predetermined, and then the corresponding first and second time points can be determined. The following explanation will take a fixed rotational speed difference, i.e., the difference between the first and second rotational speeds is predetermined, as an example.

[0080] In free-gliding mode, the time it takes for the flywheel rotor's speed to decrease from a first speed to a second speed is inversely proportional to the intensity of energy loss. Greater energy loss results in a faster speed decrease and a shorter change time; conversely, less energy loss leads to a slower speed decrease and a longer change time. Therefore, by comparing the actual change time with the normal standard time, it is possible to determine whether the flywheel rotor's losses are abnormal, and thus, to ascertain the flywheel rotor's operating state.

[0081] The standard duration is the minimum time it takes for the flywheel rotor to decrease from the first speed to the second speed under normal operating conditions during free-gliding. It can be obtained through operational tests on a flywheel rotor in normal operating conditions. For example, it can be obtained from simulation data during the flywheel rotor design phase, from statistical analysis of historical data from long-term normal operation, or from experimental calibration data.

[0082] Since the speed difference of the flywheel rotor is a fixed preset speed difference, in normal operation, during free gliding, the minimum time required for the flywheel rotor to descend by the fixed preset speed difference is fixed for each first speed; that is, each first speed corresponds to a standard duration. There is a mathematical mapping relationship between the first speed and the standard duration. Accordingly, the standard duration can be determined based on the first speed.

[0083] Optionally, the operating status of the flywheel rotor can be determined based on the variation duration and the standard duration. If the variation duration is greater than or equal to the standard duration, the operating status of the flywheel rotor is determined to be normal; if the variation duration is less than the standard duration, the operating status of the flywheel rotor is determined to be abnormal.

[0084] In this embodiment, if the variation duration is greater than or equal to the standard duration, it indicates that the flywheel rotor's descent rate from the first speed to the second speed is slower than the standard descent rate, and the energy loss is also smaller, meaning the flywheel rotor is in normal operating condition. Conversely, if the variation duration is less than the standard duration, it indicates that the flywheel rotor's descent rate from the first speed to the second speed is faster than the standard descent rate, and the flywheel rotor's energy loss is greater than the standard energy loss. This suggests that the flywheel rotor may be experiencing problems such as increased wind resistance due to decreased vacuum, increased bearing loss due to abnormal magnetic levitation bearings, or abnormal eddy current losses due to magnetic field distortion. The corresponding abnormal losses in the flywheel rotor confirm that its operating state is abnormal.

[0085] Similarly, when using power loss values ​​to determine the operating state of the flywheel rotor, with a fixed speed difference, for each first speed, there is a fixed second speed, meaning the kinetic energy loss is fixed, and each first speed also corresponds to a fixed standard duration. Therefore, with a fixed speed difference, there is a second mathematical mapping relationship between the first speed and the power loss threshold.

[0086] The mathematical mapping relationship between the first rotational speed and the aforementioned standard duration, as well as the second mathematical mapping relationship between the first rotational speed and the power loss threshold, can be obtained by conducting a series of operating tests on a flywheel rotor in a normal operating state under free-slip conditions.

[0087] Based on a fixed speed difference, the speed difference selected during the experiment is the same as the speed difference of the flywheel rotor during actual monitoring; that is, both are preset speed differences. The specific experimental procedure is as follows: Step one: Select multiple speeds from the operating speed range of the flywheel rotor as the initial speeds for the flywheel rotor during the test in free-gliding state (corresponding to the first speed in the above embodiment). Refer to the description in the above embodiment for further details.

[0088] Step two: Conduct a running test with the flywheel rotor in a free-slip state. The timing begins at the selected initial speed. Timing ends when the flywheel rotor's speed decreases to the preset speed difference, yielding the end time. The duration between the initial and end times is the running time.

[0089] Taking an initial speed of 9000 rpm and a preset speed difference of 180 rpm as an example, start the motor in the flywheel system to drive the flywheel rotor to speed up to 9000 rpm and maintain a stable speed at that speed. Disconnect the motor to allow the flywheel rotor to enter a free-glide state, and start timing simultaneously. Stop timing when the flywheel rotor speed reaches 8820 rpm. The time obtained from the timing is the runtime of this experiment, such as 781 seconds.

[0090] The above experiment was repeated multiple times, with an initial speed of 9000 rpm and a preset speed difference of 180 rpm. Each experiment yielded a runtime. For example, the runtimes of the multiple experiments included 781s, 785s, 782s, 788s, and 783s.

[0091] To ensure the accuracy and comprehensiveness of the data acquisition, the experiment can be repeated multiple times for each initial speed, such as 100 times, in order to obtain the minimum operating time of the flywheel rotor under normal conditions from the experiment.

[0092] Step 3: For each initial speed, select the shortest running time from the multiple tests and use it as the standard duration for that initial speed.

[0093] For an initial speed of 9000 rpm, among the obtained running times of 781s, 785s, 782s, 788s and 783s, the shortest running time is 781s. Therefore, the standard running time for an initial speed of 9000 rpm is 781s.

[0094] Using the above method, a standard duration can be selected for each initial speed. That is, a standard duration can be selected for each initial speed of 36000rpm, 34800rpm, 33600rpm, 32400rpm, 31200rpm, and 30000rpm.

[0095] Step four: Using the selected initial rotational speed as the independent variable and the standard duration of each initial rotational speed as the dependent variable, perform mathematical fitting to obtain the mathematical mapping relationship between the initial rotational speed and the standard duration, that is, the mathematical mapping relationship between the first rotational speed and the standard duration.

[0096] Furthermore, based on a fixed speed difference, each initial speed has a fixed ending speed, meaning the kinetic energy loss of the flywheel rotor from the initial speed to the ending speed is fixed. The initial and ending speeds can be directly substituted into the kinetic energy formula, and the difference between the two kinetic energies can be calculated to obtain the kinetic energy loss of the flywheel rotor during this period. Correspondingly, a second mathematical mapping relationship between the first speed and the power loss threshold can be determined, as follows: Step 5: By using the difference between the initial speed and the preset speed, the final speed can be obtained. Then, by substituting the initial speed and the final speed into the kinetic energy formula, the kinetic energy loss can be calculated.

[0097] With the moment of inertia of the flywheel rotor being 20... Initial speed 9000rpm = 300 rad / s, preset speed difference is 180rpm = 6 Taking rad / s as an example, the final speed is 8820 rpm = 294 rad / s, yielding a kinetic energy loss of 3564. joule.

[0098] The kinetic energy loss at each initial rotational speed can be calculated using the above method.

[0099] Step six: Calculate the ratio between kinetic energy loss and standard duration to obtain the power loss threshold for each initial rotational speed.

[0100] The standard duration obtained in the above experiment was 781s, so the calculated power loss threshold was 3654. Joules / 781s = 45.6 W≈450W.

[0101] Using the above method, the kinetic energy loss threshold for each initial rotational speed can be calculated.

[0102] Step 7: Using the selected initial rotational speed as the independent variable and the power loss threshold of each initial rotational speed as the dependent variable, perform mathematical fitting to obtain the mathematical mapping relationship between the initial rotational speed and the power loss threshold, which is the second mathematical mapping relationship between the first rotational speed and the power loss threshold.

[0103] Alternatively, instead of fitting a mathematical mapping relationship, monitoring can be performed using only the standard duration and power loss threshold obtained during the experiment. Specifically: During the flywheel rotor operation status monitoring process, the first speed of the flywheel rotor is the initial speed selected in the above-mentioned test. For example, if the flywheel rotor speed is 30200 rpm, the selected initial speed includes 30000 rpm. The speed of the flywheel rotor can be monitored. When the speed of the flywheel rotor reaches 30000 rpm, this moment is the first moment, and 30000 rpm is the first speed. Timing begins at this point. When it reaches 29820 rpm, the speed of the flywheel rotor decreases by a preset speed difference of 180 rpm. This speed is the second speed, and timing stops at this point. The moment when the timing ends is the second moment. The running time and power loss value are then calculated. The running time is compared with the standard duration corresponding to 30000 rpm, or the power loss value is compared with the power loss threshold corresponding to 30000 rpm, to determine the operating status of the flywheel rotor.

[0104] In one specific embodiment, some data regarding the power loss threshold used by the flywheel rotor are as follows: At the first speed of 1800 rpm, the power loss threshold is 72W.

[0105] At the first speed of 9000 rpm, the power loss threshold is 450W.

[0106] At the first speed of 21000rpm, the power loss threshold is 1150W.

[0107] At the first speed of 27,000 rpm, the power loss threshold is 1460W.

[0108] At the first speed of 30,000 rpm, the power loss threshold is 1620W.

[0109] At the first speed of 36000rpm, the power loss threshold is 1980W.

[0110] The above data represents the power loss threshold for a specific flywheel rotor model. For different flywheel rotor models, the specific power loss threshold will differ from the data above.

[0111] The above mainly introduced how to determine whether the flywheel's operating status is abnormal based on the flywheel rotor's operating data. The following will introduce how to further analyze the causes of the abnormality. The following two examples illustrate this from two aspects: firstly, determining the cause of the flywheel's abnormality through the flywheel rotor's operating data; and secondly, determining the cause of the flywheel's abnormality through the temperature at various locations in the flywheel energy storage system.

[0112] In some embodiments, after determining that the operating state of the flywheel rotor is abnormal, the vacuum degree of the vacuum chamber corresponding to the flywheel rotor in the free-gliding state can also be obtained; if the vacuum degree is greater than a preset vacuum degree, it is determined that the flywheel rotor has abnormal wind resistance loss; if the vacuum degree is less than or equal to the preset vacuum degree, the speed change rate curve of the flywheel rotor from the first moment to the second moment is obtained based on the speed data of multiple moments from the first moment to the second moment obtained in advance; then, the difference curve is determined based on the speed change rate curve and the preset change rate curve; wherein, the preset change rate curve is the speed change rate curve of the flywheel rotor in the normal operating state; if the difference curve is linearly related to the speed of the flywheel rotor, it is determined that the flywheel rotor has abnormal bearing loss; if the difference curve is linearly related to the square of the speed of the flywheel rotor, it is determined that the flywheel rotor has abnormal eddy current loss.

[0113] In this embodiment, considering that the abnormal losses of the flywheel rotor are mainly abnormal wind resistance losses, abnormal bearing losses, or abnormal eddy current losses, the abnormal location or cause of the flywheel rotor can be determined after the abnormal operating state of the flywheel rotor is determined.

[0114] Since wind resistance loss is directly related to the vacuum level of the vacuum chamber, the vacuum level should be checked first to determine if it meets the required vacuum level for normal flywheel rotor operation, i.e., the preset vacuum level. Here, the preset vacuum level can be selected as the maximum vacuum level under normal flywheel rotor operation. The preset vacuum level can be selected based on the application scenario of the flywheel energy storage system. For example, in grid-scale energy storage, to efficiently reduce wind resistance, the vacuum level range of the flywheel rotor under normal operation is typically 1 Pa to 10 Pa, so the preset vacuum level can be set to 10 Pa. In high-speed precision energy storage, extremely low wind resistance is required, and the vacuum level range of the flywheel rotor under normal operation is typically 0.001 Pa to 1 Pa, so the preset vacuum level can be set to 1 Pa.

[0115] The vacuum level can be indicated by absolute pressure or relative pressure.

[0116] Absolute pressure is typically between 0 and 101.325 kPa. The closer the absolute pressure is to 101.325 kPa, the greater the absolute pressure, indicating that it is closer to atmospheric pressure. Consequently, the wind resistance loss of the flywheel rotor will be greater. Conversely, the closer the absolute pressure is to 0, the smaller the absolute pressure, indicating that it is closer to absolute vacuum. Consequently, the wind resistance loss of the flywheel rotor will be smaller.

[0117] Relative pressure refers to the difference between the pressure inside the vacuum chamber and the external atmospheric pressure. When there is no vacuum inside the vacuum chamber (i.e., when the vacuum chamber is at atmospheric pressure), the absolute pressure is 0. The relative pressure is typically between -101.325 kPa and 0. The higher the relative pressure of the vacuum chamber, the closer it is to 0, indicating it is closer to atmospheric pressure, and consequently, the greater the wind resistance loss of the flywheel rotor. Conversely, the lower the relative pressure of the vacuum chamber, the closer it is to -101.325 kPa, indicating it is closer to absolute vacuum, and consequently, the smaller the wind resistance loss of the flywheel rotor.

[0118] If the vacuum level is greater than the preset vacuum level, it indicates that the pressure inside the vacuum chamber is closer to atmospheric pressure than the preset vacuum level, leading to increased wind resistance loss in the flywheel rotor and abnormal losses. If the vacuum level is less than or equal to the preset vacuum level, it indicates that the pressure inside the vacuum chamber is closer to absolute vacuum than the preset vacuum level, and the wind resistance loss of the flywheel rotor is within normal limits. Correspondingly, the abnormal losses of the flywheel rotor in this case originate from other losses, such as bearing losses or eddy current losses, and further anomaly assessments can be made for these other losses of the flywheel rotor.

[0119] Here, the cause of abnormal flywheel rotor losses can be identified by analyzing the speed change rate curve from the first moment to the second moment. Specifically, speed data from multiple moments between the first and second moments can be obtained, and the speed change rate at each moment can be calculated to form a speed change rate curve.

[0120] The preset rate of change curve is the curve of the speed change rate of the flywheel rotor under normal conditions. It can be obtained by simulation or calibration of historical normal data and can reflect the speed change characteristics of the flywheel rotor under normal losses in free-gliding state.

[0121] By calculating the difference between the speed change rate curve and the preset change rate curve, the difference curve can be obtained, which represents the additional speed change rate caused by abnormal losses.

[0122] Because abnormal losses caused by different reasons have different correlations with rotational speed, the relationship between the difference curve and rotational speed will be different.

[0123] For bearing losses, such as copper losses in magnetic levitation bearing coils and friction losses, the relationship between bearing losses and rotational speed is usually linear. According to the law of conservation of energy, the additional rate of change of rotational speed is linearly related to abnormal bearing losses. Therefore, if the difference curve is linearly related to the rotational speed, it indicates that the flywheel rotor may have abnormal bearing losses.

[0124] For abnormal eddy current losses, such as those caused by the rotor cutting through a magnetic field, the eddy current losses are related to the square of the rotational speed. According to the law of conservation of energy, the additional rate of change of rotational speed is also related to the square of the abnormal eddy current losses. Therefore, if the difference curve is linearly related to the square of the rotational speed, it indicates that the flywheel rotor may have abnormal eddy current losses.

[0125] In this embodiment, different methods are used to investigate different types of losses. First, the air resistance loss of the flywheel rotor is investigated by checking the vacuum level of the vacuum chamber. Then, the abnormal bearing loss and eddy current loss are judged by the change in rotational speed. This can accurately locate the cause of abnormality in the flywheel rotor.

[0126] In other embodiments, after determining that the flywheel rotor's operating state is abnormal, temperature data from a first moment to a second moment can be obtained at multiple locations of the flywheel energy storage system where the flywheel rotor is located; then, based on the temperature data, the temperature change rate at multiple locations of the flywheel energy storage system is determined; and based on the temperature change rate at each location and the corresponding preset temperature change threshold, the abnormal location of the flywheel energy storage system is determined.

[0127] In this embodiment, the energy loss of the flywheel energy storage system will eventually be released in the form of heat. Different types of abnormal losses will cause abnormal temperature rises at specific locations. By monitoring the temperature at multiple key locations in the flywheel energy storage system, the source of the anomaly can be accurately located, thereby determining the cause of the anomaly.

[0128] Temperature monitoring can be performed on key areas where flywheel rotor losses are likely to be concentrated, including the inner wall of the vacuum chamber, the stator of the magnetic levitation bearing, and the motor stator. Temperature data can be acquired using temperature sensors or infrared thermal imaging. Specifically, if the temperature of the inner wall of the vacuum chamber rises uniformly, it may indicate abnormal wind resistance loss, causing the gas temperature inside the vacuum chamber to rise. If the temperature of the magnetic levitation bearing stator rises abnormally, it may indicate abnormal bearing friction or excessive electromagnetic loss, leading to increased coil and bearing stator temperatures, i.e., abnormal bearing loss. If the temperature of the motor stator rises abnormally, it may indicate that eddy current heating is mainly concentrated in the rotor's conductive components and the stator's magnetic components, resulting in abnormal motor losses or eddy current losses.

[0129] The rate of temperature change is the amount of temperature change per unit time, which reflects the rate at which the temperature rises or falls.

[0130] The preset temperature change thresholds at various locations refer to the maximum rate of temperature change at each location under normal flywheel rotor operation. These thresholds can be obtained through design simulation or calibration using normal operation data. Since the heat generation and dissipation per unit time differ at different locations, the preset temperature change thresholds vary accordingly. For example, the normal heat dissipation conditions of the bearing coil are poor, resulting in heat generation far exceeding dissipation and a rapid temperature rise. Therefore, its corresponding temperature change threshold is higher than that of other locations (such as the vacuum wall cavity). Conversely, the normal heat dissipation of the vacuum cavity wall is good, resulting in heat generation slightly greater than or close to dissipation. Therefore, its corresponding temperature change threshold is lower than that of the bearing coil. Furthermore, temperature changes are also affected by rotational speed. Different flywheel rotor speeds result in different losses and correspondingly different heat generation intensities. Under free-running conditions, as the flywheel rotor speed decreases, the temperature at each location gradually decreases, and the absolute value of the temperature change rate also gradually decreases.

[0131] Therefore, a corresponding preset temperature change threshold can be selected based on the first rotational speed and the second rotational speed, or a corresponding preset temperature change threshold can be selected based on the first rotational speed, the first moment, and the second moment.

[0132] There are two methods for determining the operating state of the flywheel rotor: a fixed time interval and a fixed speed difference. The same two methods are also included when selecting the preset temperature change threshold, and they can be consistent with the method for determining the operating state of the flywheel rotor.

[0133] Based on a fixed time interval, the higher the initial rotational speed of the flywheel rotor, the greater the corresponding kinetic energy loss, and the faster the temperature rises in the critical areas where loss may be concentrated. Since the maximum kinetic energy loss of the flywheel rotor in its free-gliding state during normal operation is fixed for each initial rotational speed, the maximum temperature change value of the critical areas where loss may be concentrated is also fixed. Consequently, the maximum temperature change rate of the critical areas where loss may be concentrated is also fixed at a fixed time interval. Therefore, a corresponding preset temperature change threshold can be determined based on the initial rotational speed. Furthermore, there is a mathematical mapping relationship between the initial rotational speed and the preset temperature change thresholds for each critical area.

[0134] The process of obtaining a preset temperature change threshold through experimentation can be as follows: For a flywheel rotor operating normally, it is allowed to run at a set speed in a free-gliding state. Here, referring to the description of the threshold acquisition in the above embodiment, the initial and final speeds of the flywheel rotor are acquired, along with the temperatures of various key regions.

[0135] First, select multiple speeds from the operating speed range of the flywheel rotor and conduct a running test in a free-slip state, starting the timing at the selected initial speed during operation.

[0136] Taking an initial speed of 36,000 rpm and a preset time interval of 300 seconds as an example, the motor in the flywheel system is started to drive the flywheel rotor to speed up to 36,000 rpm and maintain a stable speed at that speed. The motor is then disconnected, allowing the flywheel rotor to enter a free-running state, and timing begins simultaneously to acquire the initial temperature of each key area. When the timer reaches 300 seconds, the final temperature of each key area is acquired.

[0137] The above experiment was repeated multiple times. The initial rotation speed was 36,000 rpm and the preset time interval was 300 s. The initial and final temperatures of each key area could be obtained in each experiment.

[0138] Secondly, for each selected first rotational speed, multiple combinations of initial and final temperatures were obtained at each critical region. The temperature difference between the initial and final temperatures was calculated and then divided by a preset time interval to obtain the temperature change rate for each combination. The largest temperature change rate was selected as the preset temperature change threshold corresponding to that first rotational speed.

[0139] For example, for an initial speed of 36,000 rpm, the maximum temperature change rate at the vacuum wall is selected from multiple tests and used as the preset temperature change threshold at the vacuum wall at the initial speed of 36,000 rpm.

[0140] Using the above method, a preset temperature change threshold at the vacuum wall can be selected at each initial rotational speed.

[0141] Next, by using the selected initial rotation speed as the independent variable and the preset temperature change threshold at each initial rotation speed at the vacuum wall as the dependent variable, mathematical fitting is performed to obtain the mathematical mapping relationship between the initial rotation speed at the vacuum wall and the preset temperature change threshold, which is the first type of mathematical mapping relationship between the first rotation speed at the vacuum wall and the preset temperature change threshold.

[0142] Finally, following the above method, a first mathematical mapping relationship between the first rotational speed and the preset temperature change threshold is also established for other key areas, such as the stator of the magnetic levitation bearing and the stator of the motor.

[0143] With a fixed speed difference, the kinetic energy loss of the flywheel rotor is fixed for each first speed. However, the shorter the time it takes for the flywheel rotor to descend to the fixed preset speed difference, the faster the temperature rises in the critical area where losses may be concentrated. Since the maximum time taken for the flywheel rotor to descend to the fixed preset speed difference for each first speed is fixed during free gliding in normal operation, the maximum temperature change value in the critical area where losses may be concentrated is fixed, and correspondingly, the maximum temperature change rate in the critical area where losses may be concentrated is also fixed. Therefore, a corresponding preset temperature change threshold can be determined based on the first speed. Furthermore, there is a mathematical mapping relationship between the first speed and the preset temperature change thresholds for each critical area.

[0144] The process of obtaining a preset temperature change threshold through experimentation can be as follows: For a flywheel rotor operating normally, it is allowed to run at a set speed in a free-slip state. Referring to the description in the above embodiments, the temperature of each key region is also acquired simultaneously when obtaining the initial and final times of the flywheel rotor.

[0145] First, select multiple speeds from the operating speed range of the flywheel rotor and conduct a running test in a free-slip state. The initial time is taken as the time of the selected initial speed during the running test.

[0146] Taking an initial speed of 9000 rpm and a preset speed difference of 180 rpm as an example, the motor in the flywheel system is started to drive the flywheel rotor to a speed of 9000 rpm and maintain a stable speed there. The motor is then disconnected, allowing the flywheel rotor to enter a free-running state. Simultaneously, timing begins, and the initial temperature of each key region is acquired. When the flywheel rotor reaches a speed of 8820 rpm, timing is stopped, and the running time of the flywheel rotor is obtained, for example, 790 seconds. The final temperature of each key region at this point is also acquired.

[0147] The above experiment was repeated multiple times. The initial speed was 9000 rpm and the preset speed difference was 180 rpm. The initial and final temperatures of each key area could be obtained in each experiment.

[0148] Subsequently, for each selected first rotational speed, multiple combinations of initial and final temperatures were obtained at each critical region. The temperature difference between the initial and final temperatures was calculated and then divided by the runtime obtained from timing to obtain the temperature change rate for each combination. The largest temperature change rate was selected as the preset temperature change threshold corresponding to that first rotational speed.

[0149] Next, referring to the method in the above-mentioned fixed time interval embodiment, with the selected initial rotation speed as the independent variable and the preset temperature change threshold of each initial rotation speed at the vacuum wall as the dependent variable, mathematical fitting is performed to obtain the mathematical mapping relationship between the initial rotation speed at the vacuum wall and the preset temperature change threshold, that is, the second mathematical mapping relationship between the first rotation speed at the vacuum wall and the preset temperature change threshold.

[0150] Finally, following the above method, a second mathematical mapping relationship between the first rotational speed and the preset temperature change threshold is also established for other key areas, such as the stator of the magnetic levitation bearing and the stator of the motor.

[0151] By comparing the temperature change rate at various locations with the corresponding preset temperature change thresholds, abnormal locations in the flywheel energy storage system can be identified. If the temperature change rate at a certain location is greater than the corresponding preset temperature change threshold, it indicates that the heat generation rate at that location exceeds the normal range, representing a concentrated area of ​​abnormal losses, and can be identified as an abnormal location, thus allowing the determination of the cause of the abnormal losses. If the temperature change rate at a certain location is less than or equal to the corresponding preset temperature change threshold, it indicates that the temperature change at that location is normal, with no abnormal losses.

[0152] Based on the above judgment, the location and cause of abnormal damage can be accurately identified.

[0153] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0154] The following are device embodiments of this application. For details not described in detail, please refer to the corresponding method embodiments described above.

[0155] Figure 2 A schematic diagram of the flywheel rotor operating status monitoring device provided in an embodiment of this application is shown. For ease of explanation, only the parts related to the embodiment of this application are shown, and are described in detail below: like Figure 2 As shown, the flywheel rotor operating status monitoring device 20 includes: The acquisition module 21 is used to acquire the first rotational speed of the flywheel rotor at the first moment and the second rotational speed at the second moment in the free-gliding state; wherein the first rotational speed is greater than the second rotational speed and the first moment is earlier than the second moment; The determination module 22 is used to determine the operating state of the flywheel rotor based on the first rotational speed, the first moment, the second rotational speed, and the second moment.

[0156] In one possible implementation, the determining module 22 is specifically used for: Based on the first rotational speed, the first moment, the second rotational speed, and the second moment, determine the power loss value of the flywheel rotor in the free-slip state; The operating status of the flywheel rotor is determined based on the power loss value.

[0157] In one possible implementation, the determining module 22 is specifically used for: Based on the first rotational speed and the moment of inertia of the flywheel rotor, determine the first rotational kinetic energy of the flywheel rotor at the first moment; Based on the second rotational speed and moment of inertia, determine the second rotational kinetic energy of the flywheel rotor at the second moment; Based on the first rotational kinetic energy, the second rotational kinetic energy, the first moment, and the second moment, determine the power loss value of the flywheel rotor in the free-sliding state.

[0158] In one possible implementation, the determining module 22 is specifically used for: Detect whether the power loss value is greater than the preset power loss threshold; If the power loss value is greater than the power loss threshold, the flywheel rotor is determined to be in an abnormal operating state. If the power loss value is less than or equal to the power loss threshold, then the flywheel rotor is considered to be in normal operating condition.

[0159] In one possible implementation, the determining module 22 is specifically used for: Based on the first and second moments, determine the duration of the flywheel rotor's change from the first speed to the second speed; Determine the standard duration of the flywheel rotor speed change based on the first and second speeds; The operating status of the flywheel rotor is determined based on the variation duration and the standard duration.

[0160] In one possible implementation, the determining module 22 is specifically used for: If the duration of the change is greater than or equal to the standard duration, then the flywheel rotor is considered to be in normal operating condition. If the duration of the change is less than the standard duration, the flywheel rotor is determined to be in an abnormal operating state.

[0161] In one possible implementation, the determining module 22 is also used for: Obtain the vacuum level of the vacuum chamber corresponding to the flywheel rotor in a free-slip state; If the vacuum level is greater than the preset vacuum level, it is determined that the flywheel rotor has abnormal wind resistance loss. If the vacuum degree is less than or equal to the preset vacuum degree, the speed change rate curve of the flywheel rotor from the first moment to the second moment is obtained based on the speed data of multiple moments from the first moment to the second moment obtained in advance. The difference curve is determined based on the speed change rate curve and the preset speed change rate curve; whereby the preset speed change rate curve is the curve of the speed change rate of the flywheel rotor under normal operating conditions. If the difference curve is linearly related to the speed of the flywheel rotor, then it is determined that there is abnormal bearing wear in the flywheel rotor. If the difference curve is linearly related to the square of the flywheel rotor speed, then it is determined that the flywheel rotor has abnormal eddy current losses.

[0162] In one possible implementation, the determining module 22 is also used for: Acquire temperature data from the first moment to the second moment at multiple locations in the flywheel energy storage system where the flywheel rotor is located; Based on temperature data, determine the rate of temperature change at multiple locations in the flywheel energy storage system; The abnormal locations of the flywheel energy storage system are determined based on the temperature change rate at each location and the corresponding preset temperature change threshold.

[0163] Figure 3 This is a schematic diagram of the flywheel energy storage system provided in an embodiment of this application. For example... Figure 3 As shown, the flywheel energy storage system 30 of this embodiment includes: a flywheel rotor 31, a speed measuring device 32, a timing device 33, and a monitoring device 34. The speed measuring device 32 measures the speed of the flywheel rotor 31 and sends the measured speed to the monitoring device 34. The timing device 33 acquires the time corresponding to different speeds of the flywheel rotor 31 and sends the acquired time to the monitoring device 34. The monitoring device 34 implements the methods described in the above embodiments.

[0164] For the sake of simplicity and clarity, only the above-described functional modules / units are used as examples. In practical applications, the functions described above can be assigned to different functional modules / units as needed. These modules / units can be implemented in hardware, software, or a combination of both.

[0165] This invention also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the methods described in the above-described method embodiments.

[0166] This invention also provides a computer program product, including a computer program. When the computer program is executed by a processor, it implements the methods described in the above-described method embodiments.

[0167] Computer programs include computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. Computer-readable media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0168] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not detailed or described in a particular embodiment can be referred to in the relevant descriptions of other embodiments. Unless otherwise specified or in conflict with logic, the terminology and / or descriptions between different embodiments are consistent and can be referenced interchangeably. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0169] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for monitoring the operating status of a flywheel rotor, characterized in that, include: The first rotational speed of the flywheel rotor in free-gliding state is obtained at a first moment and a second rotational speed at a second moment; wherein the first rotational speed is greater than the second rotational speed, and the first moment is earlier than the second moment; The operating state of the flywheel rotor is determined based on the first rotational speed, the first time, the second rotational speed, and the second time.

2. The flywheel rotor operating status monitoring method according to claim 1, characterized in that, Determining the operating state of the flywheel rotor based on the first rotational speed, the first time point, the second rotational speed, and the second time point includes: Based on the first rotational speed, the first moment, the second rotational speed, and the second moment, determine the power loss value of the flywheel rotor in the free-gliding state; The operating state of the flywheel rotor is determined based on the power loss value.

3. The flywheel rotor operating status monitoring method according to claim 2, characterized in that, Based on the first rotational speed, the first moment, the second rotational speed, and the second moment, the power loss value of the flywheel rotor in the free-gliding state is determined, including: Based on the first rotational speed and the moment of inertia of the flywheel rotor, the first rotational kinetic energy of the flywheel rotor at the first moment is determined; The second rotational kinetic energy of the flywheel rotor at the second moment is determined based on the second rotational speed and the moment of inertia. The power loss value of the flywheel rotor in free-gliding state is determined based on the first rotational kinetic energy, the second rotational kinetic energy, the first moment, and the second moment.

4. The flywheel rotor operating status monitoring method according to claim 2, characterized in that, Determining the operating state of the flywheel rotor based on the power loss value includes: Detect whether the power loss value is greater than a preset power loss threshold; If the power loss value is greater than the power loss threshold, then the operating state of the flywheel rotor is determined to be abnormal. If the power loss value is less than or equal to the power loss threshold, then the flywheel rotor is determined to be in normal operating condition.

5. The flywheel rotor operating status monitoring method according to claim 1, characterized in that, Determining the operating state of the flywheel rotor based on the first rotational speed, the first time point, the second rotational speed, and the second time point includes: Based on the first moment and the second moment, determine the duration of the flywheel rotor's change from the first speed to the second speed; The standard duration of the flywheel rotor speed change is determined based on the first speed and the second speed. The operating state of the flywheel rotor is determined based on the change duration and the standard duration.

6. The flywheel rotor operating status monitoring method according to claim 5, characterized in that, The operating state of the flywheel rotor is determined based on the variation duration and the standard duration, including: If the duration of the change is greater than or equal to the standard duration, then the operating state of the flywheel rotor is determined to be normal. If the duration of the change is less than the standard duration, then the operating state of the flywheel rotor is determined to be abnormal.

7. The flywheel rotor operating status monitoring method according to any one of claims 1 to 6, characterized in that, After determining that the flywheel rotor's operating state is abnormal, the process also includes: Obtain the vacuum level of the vacuum chamber corresponding to the flywheel rotor in the free-gliding state; If the vacuum level is greater than the preset vacuum level, it is determined that the flywheel rotor has abnormal wind resistance loss. If the vacuum degree is less than or equal to the preset vacuum degree, then based on the rotational speed data of multiple times from the first time to the second time obtained in advance, the rotational speed change curve of the flywheel rotor from the first time to the second time is obtained; Based on the speed change rate curve and the preset change rate curve, a difference curve is determined; wherein, the preset change rate curve is the speed change rate curve of the flywheel rotor under normal operating conditions; If the difference curve is linearly related to the rotational speed of the flywheel rotor, then it is determined that the flywheel rotor has abnormal bearing wear. If the difference curve is linearly related to the square of the rotational speed of the flywheel rotor, then it is determined that the flywheel rotor has abnormal eddy current losses.

8. The flywheel rotor operating status monitoring method according to any one of claims 1 to 6, characterized in that, After determining that the flywheel rotor's operating state is abnormal, the process also includes: Acquire temperature data from the first moment to the second moment at multiple locations in the flywheel energy storage system where the flywheel rotor is located; Based on the temperature data, the temperature change rate at multiple locations of the flywheel energy storage system is determined; The abnormal locations of the flywheel energy storage system are determined based on the temperature change rate at each location and the corresponding preset temperature change threshold.

9. A flywheel energy storage system, characterized in that, It includes a flywheel rotor, a speed measuring device, a timing device, and a monitoring device, wherein the monitoring device is used to implement the method as described in any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method as described in any one of claims 1 to 8.

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