Flywheel motor rotor position monitoring method and device, flywheel energy storage system and storage medium

Abstract

This application provides a method, apparatus, flywheel energy storage system, and storage medium for monitoring the rotor position of a flywheel motor, relating to the field of flywheel energy storage technology. The method includes: acquiring a first position monitoring signal and a first rotational speed of the motor rotor in the flywheel, collected by a photoelectric sensor; performing frequency multiplication processing on the first position monitoring signal to obtain a frequency-multiplied position signal corresponding to the first position monitoring signal; wherein the frequency of the frequency-multiplied position signal is a preset multiple of the frequency of the first position monitoring signal; performing phase-shift compensation on the frequency-multiplied position signal according to the first rotational speed to obtain a compensated position signal; and determining the position of the motor rotor based on the compensated position signal. This application can obtain accurate position information of the motor rotor, improve the power factor of the motor operation, ensure the efficiency and performance of the flywheel energy storage system, and thus improve the effect of the flywheel energy storage system participating in primary frequency regulation.

Description

Technical Field

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

[0002] Flywheel energy storage systems are characterized by fast response and high energy conversion efficiency. They can participate in primary frequency regulation of the power grid and quickly compensate for power when the grid frequency deviates from the dead zone frequency, thus effectively improving the stability of the grid frequency.

[0003] In a flywheel energy storage system, a high-speed rotating flywheel drives a motor to generate electricity, converting the kinetic energy stored in the system into electrical energy for release. By monitoring the position of the motor rotor, the real-time position of the rotor's magnetic field can be determined, allowing for decoupled control of the motor and improving efficiency and control performance.

[0004] In integrated flywheel energy storage systems, the flywheel's motor rotor rotates in a vacuum-suspended state, making it difficult to install mechanical position sensors. Non-contact photoelectric sensors are typically used instead. However, because photoelectric sensors can only accurately respond to a relatively low maximum rate of signal change, while the flywheel operates at a high frequency, as the motor rotor's speed increases, the position information output by the photoelectric sensor lags behind the actual position of the motor rotor. This can lead to magnetic field positioning errors, reduce the motor's power factor, and negatively impact the efficiency and performance of the flywheel energy storage system. Summary of the Invention

[0005] This application provides a method, device, flywheel energy storage system, and storage medium for monitoring the rotor position of a flywheel motor, in order to obtain accurate rotor position information and improve the power factor of the motor.

[0006] In a first aspect, embodiments of this application provide a method for monitoring the rotor position of a flywheel motor, including:

[0007] The first position monitoring signal of the motor rotor in the flywheel and the first rotational speed of the motor rotor are acquired by the photoelectric sensor.

[0008] The first position monitoring signal is frequency multiplied to obtain a frequency multiplied position signal corresponding to the first position monitoring signal; wherein the frequency of the frequency multiplied position signal is a preset multiple of the frequency of the first position monitoring signal;

[0009] Based on the first rotational speed, the double-frequency position signal is phase-shifted to obtain a compensated position signal;

[0010] The position of the motor rotor is determined based on the compensated position signal.

[0011] In one possible implementation, the step of performing phase-shift compensation on the frequency-doubled position signal based on the first rotational speed to obtain a compensated position signal includes:

[0012] Based on the first rotational speed and the preset hysteresis coefficient, determine the hysteresis angle of the hysteresis position corresponding to the first position monitoring signal relative to the actual position of the motor rotor;

[0013] Based on the hysteresis angle, the phase compensation adjustment of the frequency-doubled position signal is used to obtain the compensated position signal.

[0014] In one possible implementation, before determining the hysteresis angle of the hysteresis position corresponding to the first position monitoring signal relative to the actual position of the motor rotor based on the first rotational speed and a preset hysteresis coefficient, the method further includes:

[0015] The back EMF data of the motor at multiple different preset second speeds of the flywheel are obtained, as well as the second position monitoring signal of the motor rotor collected by the corresponding photoelectric sensor;

[0016] For each second rotational speed, the back EMF pulse signal corresponding to the second rotational speed is determined based on the back EMF data corresponding to that second rotational speed; the angle difference of the motor rotor at that second rotational speed is calculated based on the back EMF pulse signal corresponding to the second rotational speed and the second position monitoring signal.

[0017] The hysteresis coefficient of the motor rotor is determined based on each second rotational speed and its corresponding angle difference.

[0018] In one possible implementation, the phase compensation adjustment of the frequency-doubled position signal based on the hysteresis angle to obtain the compensated position signal includes:

[0019] Based on the preset multiple, determine the position angle of the motor rotor corresponding to a single pulse in the frequency multiplication position signal;

[0020] Based on the hysteresis angle and the position angle, determine the number of first pulses that need to be compensated and adjusted for the phase of the frequency-doubled position signal;

[0021] Based on the first number of pulses, the frequency-doubled position signal is adjusted to obtain a compensated position signal.

[0022] In one possible implementation, adjusting the frequency-doubled position signal based on the first pulse count to obtain a compensated position signal includes:

[0023] Based on the preset multiple, determine the number of frequency-multiplying pulses of the frequency-multiplying position signal corresponding to one pulse of the first position monitoring signal;

[0024] Calculate the actual number of second pulses counted during the phase shift process based on the number of frequency doubling pulses and the number of first pulses;

[0025] When the rising edge of the current cycle in the first position monitoring signal is detected, pulse counting of the frequency-doubled position signal begins; and the rising edge when the pulse count reaches the second pulse number is determined as the compensation rising edge of the next cycle in the compensation position signal; and the compensation falling edge corresponding to the compensation rising edge in the compensation position signal is determined.

[0026] The compensation position signal is obtained based on the compensation rising edge and the compensation falling edge.

[0027] In one possible implementation, the step of frequency multiplication of the first position monitoring signal to obtain a frequency-multiplied position signal corresponding to the first position monitoring signal includes:

[0028] The first position monitoring signal is subjected to phase-locked loop and frequency multiplier processing using a preset phase-locked loop and frequency multiplier to obtain a frequency-multiplied position signal corresponding to the first position monitoring signal.

[0029] In one possible implementation, obtaining the first rotational speed of the motor rotor includes:

[0030] The first rotational speed of the motor rotor is calculated based on the frequency of the first position monitoring signal.

[0031] Secondly, embodiments of this application provide a flywheel motor rotor position monitoring device, comprising:

[0032] The acquisition module is used to acquire the first position monitoring signal of the motor rotor in the flywheel and the first rotational speed of the motor rotor collected by the photoelectric sensor;

[0033] A frequency multiplier module is used to perform frequency multiplication processing on the first position monitoring signal to obtain a frequency multiplier position signal corresponding to the first position monitoring signal; wherein the frequency of the frequency multiplier position signal is a preset multiple of the frequency of the first position monitoring signal;

[0034] A phase-shifting module is used to perform phase-shifting compensation on the frequency-doubled position signal according to the first rotational speed to obtain a compensated position signal;

[0035] The determination module is used to determine the position of the motor rotor based on the compensated position signal.

[0036] Thirdly, embodiments of the present invention provide a flywheel energy storage system, including a motor rotor, a photoelectric sensor, and a position monitoring device, wherein the position monitoring device is used to implement the method in the first aspect or any possible implementation of the first aspect.

[0037] 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.

[0038] 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.

[0039] The beneficial effects of the embodiments in this application compared with the prior art are:

[0040] This application embodiment performs frequency multiplication on the first position monitoring signal of the motor rotor in the flywheel, which is collected by a photoelectric sensor, to obtain a frequency-multiplied position signal corresponding to the position monitoring signal. Frequency multiplication can improve signal resolution and enable the frequency-multiplied position signal to have phase shift compensation capability. By using the first rotational speed of the motor rotor to perform phase shift compensation on the frequency-multiplied position signal, the position deviation caused by the delay of the position monitoring signal can be corrected while taking into account the influence of the rotational speed of the motor rotor, so as to obtain an accurate compensated position signal. Then, the position of the motor rotor can be determined by the compensated position signal, so as to obtain an accurate motor rotor position. This allows for accurate motor control, improves the power factor of the motor operation, ensures the efficiency and performance of the flywheel energy storage system, and thus improves the effect of the flywheel energy storage system participating in primary frequency regulation. Attached Figure Description

[0041] 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.

[0042] Figure 1 This is a schematic diagram comparing the signal output by the photoelectric sensor provided in the embodiments of this application with the signal of the actual position of the motor rotor;

[0043] Figure 2 This is an application scenario diagram of the flywheel motor rotor position monitoring method provided in the embodiments of this application;

[0044] Figure 3 This is a flowchart illustrating the implementation of the flywheel motor rotor position monitoring method provided in this application embodiment;

[0045] Figure 4 This is a schematic diagram of the frequency-doubled position signal provided in an embodiment of this application;

[0046] Figure 5 This is a schematic diagram of the phase-locked loop frequency multiplier provided in the embodiments of this application;

[0047] Figure 6 This is a schematic diagram of the compensated position signal provided in an embodiment of this application;

[0048] Figure 7 This is a schematic diagram of pulse counting during the phase shifting process provided in an embodiment of this application;

[0049] Figure 8 This is a schematic diagram of the structure of the flywheel motor rotor position monitoring device provided in the embodiments of this application;

[0050] Figure 9 This is a schematic diagram of the flywheel energy storage system provided in the embodiments of this application. Detailed Implementation

[0051] 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.

[0052] When using photoelectric sensors to detect the position of a flywheel motor rotor, the maximum rate of signal change that the photoelectric sensor can accurately respond to is relatively low, resulting in a narrow detectable frequency response range (i.e., a narrow bandwidth). Since the flywheel operates at a high frequency, as the motor rotor speed increases, the position signal output by the photoelectric sensor lags behind the actual position of the motor rotor. For example, when the motor rotor speed exceeds 10,000 rpm, the signal output by the photoelectric sensor will exhibit distortion and lag. Figure 1 As shown, the upper signal reflects the actual position of the motor rotor, while the lower signal is the output signal from the photoelectric sensor. The rising edge of the photoelectric sensor's output signal lags behind the rising edge of the actual position signal by a time t1-t0. Furthermore, the rising edge of the photoelectric sensor's output signal exhibits a distorted arc shape.

[0053] Flywheel motors typically employ permanent magnet synchronous motors. Their vector control requires precise acquisition of the real-time position of the rotor's magnetic field. Using this position as a reference, the stator current is decomposed into excitation and torque components. Due to the position lag in the output signal from the photoelectric sensor, the reference for decomposing the stator current will be biased, leading to inaccurate magnetic field orientation and incorrect current vector angle. Consequently, a negative current component will be generated at the reference of the motor rotor's true position, weakening the component of the rotor's permanent magnet magnetic field, increasing the reactive component, reducing the power factor of the motor, and affecting the efficiency and performance of the flywheel energy storage system.

[0054] In order to accurately obtain the position information of the motor rotor, the position monitoring signal obtained by the photoelectric sensor is frequency multiplied in this embodiment to improve the resolution of the signal and enable the frequency multiplied position signal to have the ability of phase shift compensation; the phase shift compensation of the frequency multiplied position signal is performed by the rotational speed of the motor rotor to correct the position deviation of the motor rotor in the position monitoring signal, so as to obtain an accurate compensated position signal, thereby obtaining an accurate position of the motor rotor for subsequent precise control.

[0055] 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.

[0056] Figure 2 This diagram illustrates an application scenario of the flywheel motor rotor position monitoring method provided in an embodiment of the present invention. Figure 2 The motor rotor shown has three black zones and three white zones, indicating different positions on the motor rotor. For example, the black and white zones can be aligned with the position of the rotor's magnetic field to monitor the position of the motor rotor and orient the magnetic field.

[0057] Three photoelectric sensors can be suspended above the motor rotor. When the motor rotor rotates, the photoelectric sensors output a low level when detecting a dark area and a high level when detecting a bright area, thus providing feedback on the motor rotor's position. The three photoelectric sensors are evenly distributed above the motor rotor, and together they output three sets of position signals with an angle difference of 120°.

[0058] See Figure 3 The flowchart illustrating the implementation of the flywheel motor rotor position monitoring method provided in this embodiment of the invention is described in detail below:

[0059] Step 301: Obtain the first position monitoring signal of the motor rotor in the flywheel and the first rotational speed of the motor rotor collected by the photoelectric sensor.

[0060] Here, the photoelectric sensor can also be a non-contact infrared sensor. By acquiring the position of the motor rotor through the photoelectric sensor, the first position monitoring signal output by the photoelectric sensor can be obtained.

[0061] Optionally, the first rotational speed of the motor rotor can be obtained by calculating the first rotational speed of the motor rotor based on the frequency of the first position monitoring signal.

[0062] In this embodiment, since the first position monitoring signal is obtained by monitoring the motor rotor, the motor rotor speed can be calculated in real time by measuring the frequency of the first position monitoring signal. For example, the motor rotor speed = (frequency of the first position monitoring signal × 60) / number of pulses per revolution of the motor rotor. Figure 1The motor rotor shown has 3 pulses per revolution.

[0063] Since the frequency can be obtained from the pulse period, the frequency of the first position monitoring signal can be obtained by measuring the time of a single pulse period. That is, the frequency of the first position monitoring signal = 1 / pulse period, then the motor rotor speed = 60 / (the first position monitoring signal / pulse period × the number of pulses per revolution of the motor rotor).

[0064] Since the frequency can also be obtained by pulse counting, the number of pulses of the first position monitoring signal can be counted within a fixed time window. Then the motor rotor speed = (pulse count × 60) / (time window × number of pulses per motor rotor revolution).

[0065] Step 302: The first position monitoring signal is frequency multiplied to obtain a frequency multiplied position signal corresponding to the first position monitoring signal; wherein the frequency of the frequency multiplied position signal is a preset multiple of the frequency of the first position monitoring signal.

[0066] Theoretically, by measuring the period of the first position monitoring signal, the output pulse can be triggered in advance within the next cycle, achieving phase shifting of the signal. However, direct phase shifting has poor accuracy. Furthermore, the rotational speed of the motor rotor is not constant but may change slowly. Only when the next pulse arrives can the length of the previous cycle be known, allowing for compensation in the next cycle. This results in a control delay of one cycle. Therefore, it is impossible to directly shift the phase of the first position monitoring signal to obtain an accurate motor rotor position.

[0067] Since the position angle of the motor rotor corresponding to one cycle consisting of high and low levels in the first position monitoring signal is fixed, the frequency of the signal can be increased by frequency doubling, thus increasing the number of pulses in the signal. Correspondingly, the position angle of the motor rotor corresponding to each pulse in the frequency-doubled signal is also fixed, thereby improving the signal resolution. The pulses in the frequency-doubled signal can be directly used for phase shifting without needing to adjust the phase shift based on the duration corresponding to the cycle in the signal, thereby improving the accuracy of phase shifting.

[0068] In this embodiment, see Figure 4 By performing frequency multiplication on the first position monitoring signal, a frequency-multiplied position signal corresponding to the first position monitoring signal can be obtained. The frequency-multiplied position signal improves the signal resolution compared to the original first position monitoring signal. Furthermore, the phase of the frequency-multiplied position signal is the same as the phase of the first position monitoring signal, meaning the position of the motor rotor corresponding to the frequency-multiplied position signal is the same as the position of the motor rotor corresponding to the first position monitoring signal.

[0069] like Figure 1As shown, the motor rotor is divided into 6 regions, forming 3 groups. Correspondingly, for every revolution of the motor rotor, the first position monitoring signal will contain three cycles, each cycle consisting of a high level and a low level, i.e., a pulse. At this time, one cycle (or pulse) corresponds to a 120° position angle of the motor rotor.

[0070] For example, if the frequency of the frequency-doubled position signal obtained through frequency doubling is 120 times the frequency of the first position monitoring signal, then one period of the first position monitoring signal corresponds to 120 periods in the frequency-doubled position signal. This is equivalent to dividing one period of the first position monitoring signal into 120 periods. In the frequency-doubled position signal, one period (or pulse) corresponds to a 1° position angle of the motor rotor, thus improving signal resolution.

[0071] Optionally, the first position monitoring signal can be frequency multiplied to obtain a frequency multiplied position signal corresponding to the first position monitoring signal. This can be achieved by using a preset phase-locked loop and frequency multiplier to perform phase-locked frequency multiplication on the first position monitoring signal.

[0072] In this embodiment, a phase-locked loop (PLL) and a frequency multiplier can be used to achieve phase-locked frequency multiplication. The PLL ensures that the phase of the motor rotor corresponding to the obtained frequency-multiplied position signal is consistent with the phase of the motor rotor corresponding to the first position monitoring signal, preventing phase deviation in the generated frequency-multiplied position signal. The frequency multiplier generates a high-frequency signal to obtain the desired frequency-multiplied position signal, thus increasing the signal frequency.

[0073] Here, the phase-locked loop (PLL) and frequency multiplier can be implemented using a PLL, specifically a digital PLL or an analog PLL. Alternatively, it can be implemented using a physical device's PLL.

[0074] like Figure 5 As shown, a phase-locked loop (PLL) frequency multiplier may include a phase detector, a loop filter, a voltage-controlled oscillator (or a digitally controlled oscillator), and an N-fold divider. The phase detector compares the phase difference between the original signal and the feedback signal and transmits this phase difference to the loop filter. The loop filter converts the phase difference into a smooth control voltage and filters out high-frequency noise. The voltage-controlled oscillator generates and outputs a high-frequency signal based on the control voltage; the frequency of this high-frequency signal is N × the frequency of the original signal. The N-fold divider divides the high-frequency signal generated by the voltage-controlled oscillator to obtain the feedback signal, which is then transmitted to the phase detector for comparison and adjustment.

[0075] Step 303: Based on the first rotational speed, perform phase shift compensation on the frequency-doubled position signal to obtain the compensated position signal.

[0076] In this embodiment, the position of the motor rotor corresponding to the first position detection signal collected by the photoelectric sensor varies with different rotational speeds, resulting in varying degrees of lag relative to the actual position of the motor rotor. Therefore, the required phase shift angle can be determined by acquiring the first rotational speed of the motor rotor, thereby achieving phase shift compensation of the frequency-doubled position signal. This shifts the signal to a position corresponding to the actual position of the motor rotor, resulting in a compensated position signal.

[0077] Here, the frequency of the compensated position signal can be a preset multiple of the frequency of the first position monitoring signal. That is, the compensated position signal is shifted forward relative to the frequency-multiplied position signal, and the compensated position signal retains high-precision characteristics. For example... Figure 6 As shown, the upper part shows the frequency-doubled position signal and its position feedback information relative to the motor rotor, while the lower part shows the compensated position signal and its position feedback information relative to the motor rotor.

[0078] The frequency of the compensation position signal can also be the same as the frequency of the first position monitoring signal, that is, the compensation position signal is shifted forward relative to the first position monitoring signal, and the high and low levels of the compensation position signal correspond to the area set on the motor rotor.

[0079] Step 304: Determine the position of the motor rotor based on the compensated position signal.

[0080] This application embodiment performs frequency multiplication on the first position monitoring signal of the motor rotor in the flywheel acquired by the photoelectric sensor, obtaining a frequency-multiplied position signal corresponding to the position monitoring signal. Frequency multiplication improves signal resolution and enables the frequency-multiplied position signal to have phase-shift compensation capability. By using the first rotational speed of the motor rotor to perform phase-shift compensation on the frequency-multiplied position signal, the position deviation caused by the delay in the position monitoring signal can be corrected, considering the influence of the motor rotor's rotational speed, resulting in an accurate compensated position signal. The position of the motor rotor is then determined using the compensated position signal, obtaining an accurate motor rotor position. This allows for accurate motor control, improving the motor's power factor and ensuring the efficiency and performance of the flywheel energy storage system. This, in turn, enhances the effect of the flywheel energy storage system participating in primary frequency regulation. Furthermore, the flywheel motor rotor position monitoring method provided in this application embodiment is mainly applied to flywheel energy storage systems and is not limited to flywheel energy storage systems in primary frequency regulation.

[0081] In some embodiments, the compensated position signal is obtained by performing phase-shift compensation on the frequency-doubled position signal according to the first rotational speed. This can be achieved by: determining the lag angle of the lag position corresponding to the first position monitoring signal relative to the actual position of the motor rotor according to the first rotational speed and a preset lag coefficient; and adjusting the phase of the frequency-doubled position signal based on the lag angle to obtain the compensated position signal.

[0082] In this embodiment, the hysteresis angle between the hysteresis position of the motor rotor corresponding to the first position monitoring signal and the actual position of the motor rotor is usually proportional to the rotational speed of the motor rotor. Therefore, when the rotational speed of the motor rotor exceeds a preset speed (e.g., 10000 rpm), and there is a hysteresis angle between the position of the motor rotor corresponding to the first position monitoring signal and the actual position, the corresponding hysteresis angle can be determined by the rotational speed of the motor rotor, and the hysteresis angle can be used to compensate for the frequency-doubled position signal, so that the position of the motor rotor corresponding to the compensated position signal corresponds to the actual position of the motor rotor.

[0083] The hysteresis coefficient can be obtained through experimental calibration of the motor rotor, such as by conducting a no-load comparison experiment. Furthermore, different flywheel energy storage systems or motor rotors have different hysteresis coefficients, requiring separate calibration to obtain the appropriate hysteresis coefficient.

[0084] Optionally, before determining the lag angle of the lag position corresponding to the first position monitoring signal relative to the actual position of the motor rotor based on the first rotational speed and a preset lag coefficient, the following can also be done:

[0085] Step 1: Obtain the back EMF data of the motor at multiple different preset second speeds of the flywheel, as well as the second position monitoring signal of the motor rotor collected by the corresponding photoelectric sensor.

[0086] Here, the back EMF data of the motor can reflect the actual position of the motor rotor. Since the back EMF data is generated during motor operation, it cannot be directly obtained or used to control the motor. Therefore, during motor operation, the back EMF data cannot be used to monitor the position of the motor rotor to solve the problem of this application. However, the actual position of the motor rotor can be obtained later through the back EMF data to calibrate the hysteresis coefficient.

[0087] The second position monitoring signal is the signal obtained by the photoelectric sensor when the motor rotor runs at different second speeds, which reflects the position of the motor rotor as monitored and obtained by the photoelectric sensor.

[0088] Step 2: For each second speed, determine the back EMF pulse signal corresponding to the second speed based on the back EMF data corresponding to the second speed; calculate the angle difference of the motor rotor corresponding to the second speed based on the back EMF pulse signal and the second position monitoring signal.

[0089] In this embodiment, the back EMF data and the second position monitoring signal at each second speed are compared to obtain the angle difference of the motor rotor between the two methods, wherein the position of the motor rotor corresponding to the second position monitoring signal is lagging.

[0090] Here, the back EMF data can be generated into a back EMF pulse signal. The peak value, valley value, and zero-crossing point of this back EMF pulse signal correspond to fixed positions on the motor rotor, and the black and white areas on the motor rotor also correspond to fixed positions on the motor rotor. Therefore, there is a fixed correspondence between the back EMF pulse signal and the second position monitoring signal. This correspondence can be obtained through calibration.

[0091] by Figure 2 Taking the alignment of the black and white regions on the rotor of a medium-sized motor with the rotor magnetic field as an example, the peak value of the back EMF pulse signal corresponds to the boundary between the black and white regions on the rotor, and the valley value corresponds to the boundary between the white and black regions on the rotor. That is, theoretically, the peak value of the back EMF pulse signal should correspond to the rising edge of the position monitoring signal, and theoretically, the valley value should correspond to the falling edge of the position monitoring signal.

[0092] Alternatively, a back EMF pulse signal can be generated according to preset positions on the back EMF data. These preset positions can be peak values ​​and valley values. The peak value in the back EMF data is the rising edge of the back EMF pulse signal, and the valley value is the falling edge, thus generating the back EMF pulse signal. Correspondingly, the rising edge of the back EMF pulse signal should correspond to the rising edge of the position monitoring signal, and theoretically, the falling edge of the back EMF pulse signal should correspond to the falling edge of the position monitoring signal.

[0093] Based on this, by comparing the back EMF pulse signal and the second position monitoring signal, the angle difference between the position of the motor rotor corresponding to the back EMF pulse signal and the position of the motor rotor corresponding to the second position monitoring signal can be obtained.

[0094] Here, the angle difference between the position of the motor rotor corresponding to the position monitoring signal collected by the photoelectric sensor and the actual position of the motor rotor is usually smaller than the angle corresponding to a set of partitions in the motor rotor. Figure 2 For example, the angle difference mentioned above is usually less than the angle corresponding to a white area and a black area, that is, the angle difference mentioned above is usually less than 120°.

[0095] In other words, the delay of the position monitoring signal acquired by the photoelectric sensor usually does not exceed the length of one cycle of the signal.

[0096] Step 3: Determine the hysteresis coefficient of the motor rotor based on each second rotational speed and its corresponding angle difference.

[0097] In this embodiment, the relationship between the motor rotor speed and the angle difference can be obtained by fitting each second rotational speed with its corresponding angle difference, thereby obtaining the hysteresis coefficient. Here, angle difference = hysteresis coefficient × rotational speed. Correspondingly, the hysteresis angle in the above embodiment can be calculated using the hysteresis coefficient and the rotational speed.

[0098] Here, through experimental calibration using back EMF data and the second position monitoring signal, the hysteresis coefficient of the motor rotor can be determined when there is a hysteresis in the position monitoring signal acquired by the photoelectric sensor. This hysteresis coefficient is usually the same for the same motor rotor under the same operating conditions. Therefore, when actually compensating for the position monitoring signal, the angle difference can be directly calculated using this pre-calibrated hysteresis coefficient and the motor rotor speed. Position compensation can then be performed using the calculated angle difference without waiting for back EMF data, enabling real-time compensation of the position monitoring signal.

[0099] Furthermore, the accuracy of the motor rotor position reflected by back EMF data is typically within ±3°. When using photoelectric sensors to collect position monitoring signals from a high-speed motor rotor, the rotor speed is extremely high, exceeding 10,000 rpm, and even reaching over 40,000 rpm. In this case, the electrical angle corresponding to the hysteresis angle of the position monitoring signal collected by the photoelectric sensor will exceed 10°, far exceeding the electrical angle corresponding to the calibration accuracy of the back EMF data. Therefore, the hysteresis coefficient obtained from the back EMF data calibration can be used for position compensation to reduce the delay of the position monitoring signal.

[0100] In some embodiments, the phase compensation adjustment of the frequency-doubled position signal based on the hysteresis angle can be used to obtain a compensated position signal. This can be achieved by first determining the position angle of the motor rotor corresponding to a single pulse in the frequency-doubled position signal according to a preset multiple; then determining the number of first pulses for which the phase of the frequency-doubled position signal needs to be compensated and adjusted based on the hysteresis angle and the position angle; and finally, adjusting the frequency-doubled position signal based on the number of first pulses to obtain the compensated position signal.

[0101] In this embodiment, one period of the first position monitoring signal corresponds to a preset multiple of the periods of the frequency-multiplied position signal. The angle of the motor rotor corresponding to one period of the first position monitoring signal is fixed, such as... Figure 1 The diagram shows a white area and a black area corresponding to 120°. Therefore, depending on the preset multiplier when multiplying the signal frequency, the position angle of the motor rotor corresponding to a single pulse in the multiplied position signal will also be different, that is, the accuracy will be different. Therefore, it is necessary to first determine the position angle of the motor rotor corresponding to a single pulse in order to perform position compensation.

[0102] Here, the hysteresis angle is the angular difference between the position of the motor rotor corresponding to the frequency-doubled position signal and the actual position of the motor rotor. By using the hysteresis angle and the position angle, the number of pulses required to compensate for the frequency-doubled position signal can be determined, that is, the number of the first pulses that the frequency-doubled position signal needs to be shifted forward. This allows for precise adjustment of the frequency-doubled position signal, resulting in a compensated position signal corresponding to the position of the motor rotor.

[0103] Among them, the frequency-doubled position signal can be adjusted by a programmable phase shifter or a phase interpolator, and the phase-adjustable pulse can be generated by a time-delay phase-locked loop or an interpolation algorithm.

[0104] Additionally, pulses can be generated using hysteresis angles and phase accumulators. The high-frequency clock in the phase accumulator is set with a relative time unit (tick), with each tick corresponding to a time interval. By accumulating multiple ticks, when the accumulated value reaches a preset threshold, the accumulator rolls back to generate a rising edge. Therefore, the hysteresis angle can be converted into the number of relative time units (ticks) of the high-frequency clock in the phase accumulator, and this value can be inserted into the initial value of the phase accumulator, causing the next cycle to be advanced. Furthermore, since the flywheel speed varies, the initial value of the phase accumulator can be dynamically adjusted using the flywheel speed calculated in the previous cycle to perform phase compensation.

[0105] Optionally, in this embodiment, the frequency-doubled position signal is adjusted based on the first pulse count to obtain the compensated position signal. This can be achieved by first determining the number of frequency-doubled pulses of the frequency-doubled position signal corresponding to one pulse of the first position monitoring signal according to a preset multiple; then calculating the actual number of second pulses counted during the phase shift process based on the number of frequency-doubled pulses and the first pulse count; when the rising edge of the current cycle in the first position monitoring signal is detected, the pulse counting of the frequency-doubled position signal begins; and the rising edge when the pulse count reaches the second pulse count is determined as the compensation rising edge of the next cycle in the compensated position signal; the compensation falling edge corresponding to the compensation rising edge in the compensated position signal is determined; finally, the compensated position signal is obtained based on the compensation rising edge and the compensation falling edge.

[0106] In this embodiment, the compensation position signal can also be obtained by pulse counting. By counting the rising edges of the frequency-doubled position signal, the rising edge of the compensation signal in the next cycle of the compensation position signal can be predicted, thereby obtaining the compensation position signal.

[0107] Since the frequency of the frequency-doubled position signal is a preset multiple of the frequency of the first position monitoring signal, one pulse of the first position monitoring signal corresponds to a preset multiple of the frequency-doubled position signal pulses, that is, the value of the number of frequency-doubled pulses is a preset multiple.

[0108] Since the future signal is unknown, prediction can only be made using existing periods or pulses. Therefore, it is necessary to count the existing pulses. The first pulse count represents the number of pulses required to advance the frequency-doubled position signal, and the frequency-doubled pulse count represents the number of pulses corresponding to one period of the first position monitoring signal. The second pulse count, which can actually be accumulated during the phase shift, can then be calculated using the frequency-doubled pulse count and the first pulse count. For example... Figure 7As shown, one cycle (or pulse) of the first position monitoring signal corresponds to four cycles (or pulses) of the frequency-doubled position signal, and the hysteresis angle corresponds to one cycle (or pulse). That is, if the number of the first pulse is 1 and the number of the frequency-doubled pulses is 4, then the number of the second pulse is 3. When the rising edge of the current cycle in the first position monitoring signal is detected, the pulse counting of the frequency-doubled position signal begins. The pulse count corresponding to the rising edge of the current cycle in the first position monitoring signal is 0, and the next pulse count is 1. When the pulse count of the frequency-doubled position signal is 3, it corresponds exactly to the rising edge of the next cycle of the motor rotor.

[0109] Alternatively, when the rising edge of the current cycle in the first position monitoring signal is detected, the pulse counting of the frequency-doubled position signal begins. The pulse count corresponding to the rising edge of the current cycle in the first position monitoring signal is 1, and the next pulse count is 2. When the pulse count of the frequency-doubled position signal is the second pulse count + 1, that is, 4, it corresponds exactly to the rising edge of the next cycle of the motor rotor.

[0110] By detecting the rising or falling edge of the first position monitoring signal, pulse counting of the frequency-doubled position signal can begin. Taking rising edge detection as an example, when the rising edge of the first position monitoring signal is detected, pulse counting begins. The rising edge at which the pulse count of the frequency-doubled position signal reaches the second pulse count is the predicted rising edge of the next cycle after compensation, i.e., the compensated rising edge. By analyzing the relationship between the rising and falling edges in the signal, the falling edge of the next cycle after compensation, i.e., the compensated falling edge, can be predicted. This can be achieved by counting the number of pulses of the frequency-doubled position signal corresponding to the rising and falling edges within one cycle of the first position monitoring signal. Alternatively, the falling edge of the first position monitoring signal can be detected, and pulse counting can be performed in the same manner as the rising edge to obtain the compensated falling edge.

[0111] By determining the rising edge and falling edge of the compensation signal, the high and low levels of the compensation position signal can be determined, thus obtaining the compensation position signal.

[0112] Here, the signal delay usually does not exceed the length of one cycle of the first position monitoring signal. Therefore, the rising edge of the next cycle can be predicted using the rising edge of the current cycle.

[0113] This embodiment of the application performs frequency multiplication on the first position monitoring signal of the motor rotor in the flywheel, which is collected by a photoelectric sensor, to obtain a frequency-multiplied position signal corresponding to the position monitoring signal. Frequency multiplication improves signal resolution and enables the frequency-multiplied position signal to have phase-shift compensation capability. By using the first rotational speed of the motor rotor to perform phase-shift compensation on the frequency-multiplied position signal, the position deviation caused by the delay of the position monitoring signal can be corrected, considering the influence of the motor rotor's rotational speed, resulting in an accurate compensated position signal. Then, the position of the motor rotor is determined using the compensated position signal, obtaining an accurate motor rotor position. This allows for accurate motor control, improving the motor's power factor and ensuring the efficiency and performance of the flywheel energy storage system, thereby enhancing the effect of the flywheel energy storage system in primary frequency regulation. Specifically, by using the first rotational speed of the motor rotor and the hysteresis coefficient, the hysteresis angle of the hysteresis position corresponding to the first position monitoring signal relative to the actual position of the motor rotor can be calculated. This hysteresis angle, representing the angle the signal needs to be advanced, can be used to achieve phase compensation adjustment, obtaining a compensated position signal that accurately reflects the position of the motor rotor.

[0114] 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.

[0115] The following are device embodiments of this application. For details not described in detail, please refer to the corresponding method embodiments described above.

[0116] Figure 8 A schematic diagram of the flywheel motor rotor position 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:

[0117] like Figure 8 As shown, the flywheel motor rotor position monitoring device 80 includes:

[0118] The acquisition module 81 is used to acquire the first position monitoring signal of the motor rotor in the flywheel and the first speed of the motor rotor collected by the photoelectric sensor;

[0119] The frequency multiplier module 82 is used to perform frequency multiplication processing on the first position monitoring signal to obtain a frequency multiplier position signal corresponding to the first position monitoring signal; wherein, the frequency of the frequency multiplier position signal is a preset multiple of the frequency of the first position monitoring signal;

[0120] The phase-shifting module 83 is used to perform phase-shifting compensation on the frequency-doubled position signal according to the first rotational speed to obtain a compensated position signal;

[0121] The determination module 84 is used to determine the position of the motor rotor based on the compensated position signal.

[0122] In one possible implementation, the phase-shifting module 83 is specifically used for:

[0123] Based on the first rotational speed and the preset hysteresis coefficient, determine the hysteresis angle of the hysteresis position corresponding to the first position monitoring signal relative to the actual position of the motor rotor;

[0124] Based on the hysteresis angle, the phase compensation adjustment of the frequency-doubled position signal is used to obtain the compensated position signal.

[0125] In one possible implementation, the flywheel motor rotor position monitoring device 80 further includes a calibration module for:

[0126] Acquire the back EMF data of the motor at multiple different preset second speeds of the flywheel, as well as the second position monitoring signal of the motor rotor collected by the corresponding photoelectric sensor;

[0127] For each second rotational speed, the back EMF pulse signal corresponding to the second rotational speed is determined based on the back EMF data corresponding to that second rotational speed; the angle difference of the motor rotor at that second rotational speed is calculated based on the back EMF pulse signal corresponding to the second rotational speed and the second position monitoring signal.

[0128] The hysteresis coefficient of the motor rotor is determined based on each second rotational speed and its corresponding angle difference.

[0129] In one possible implementation, the phase-shifting module 83 is specifically used for:

[0130] Based on the preset multiplier, determine the position angle of the motor rotor corresponding to a single pulse in the frequency multiplier position signal;

[0131] Based on the hysteresis angle and position angle, determine the number of first pulses required for phase compensation adjustment of the frequency-doubled position signal;

[0132] Based on the number of the first pulses, the frequency-doubled position signal is adjusted to obtain the compensated position signal.

[0133] In one possible implementation, the phase-shifting module 83 is specifically used for:

[0134] Based on a preset multiple, determine the number of frequency-multiplying pulses of the frequency-multiplying position signal corresponding to one pulse of the first position monitoring signal;

[0135] Calculate the actual number of the second pulses counted during the phase shift process based on the number of frequency doubling pulses and the number of the first pulse;

[0136] When the rising edge of the current cycle in the first position monitoring signal is detected, pulse counting of the frequency-doubled position signal begins; and the rising edge when the pulse count reaches the second pulse number is determined as the compensation rising edge of the next cycle in the compensation position signal; and the compensation falling edge corresponding to the compensation rising edge in the compensation position signal is determined.

[0137] The compensation position signal is obtained based on the compensation rising edge and compensation falling edge.

[0138] In one possible implementation, the frequency multiplier module 82 is specifically used for:

[0139] The first position monitoring signal is subjected to phase-locked loop and frequency multiplier processing using a preset phase-locked loop and frequency multiplier to obtain a frequency multiplied position signal corresponding to the first position monitoring signal.

[0140] In one possible implementation, module 81 is specifically used for:

[0141] The first rotational speed of the motor rotor is calculated based on the frequency of the first position monitoring signal.

[0142] Figure 9 This is a schematic diagram of the flywheel energy storage system provided in an embodiment of this application. For example... Figure 9 As shown, the flywheel energy storage system of this embodiment includes a motor rotor, a photoelectric sensor, and a position monitoring device. The photoelectric sensor is used to collect the position signal of the motor rotor and send it to the position monitoring device. The position monitoring device is used to implement the flywheel motor rotor position monitoring method provided in the various method embodiments of this application.

[0143] 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.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] 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 rotor position of a flywheel motor, characterized in that, include: The first position monitoring signal of the motor rotor in the flywheel and the first rotational speed of the motor rotor are acquired by the photoelectric sensor. The first position monitoring signal is subjected to frequency multiplication to obtain a frequency multiplied position signal corresponding to the first position monitoring signal; wherein the frequency of the frequency multiplied position signal is a preset multiple of the frequency of the first position monitoring signal; Based on the first rotational speed, the double-frequency position signal is phase-shifted to obtain a compensated position signal; The position of the motor rotor is determined based on the compensated position signal; The step of performing phase-shift compensation on the frequency-doubled position signal based on the first rotational speed to obtain a compensated position signal includes: Based on the first rotational speed and the preset hysteresis coefficient, determine the hysteresis angle of the hysteresis position corresponding to the first position monitoring signal relative to the actual position of the motor rotor; Based on the preset multiple, determine the position angle of the motor rotor corresponding to a single pulse in the frequency multiplication position signal; Based on the hysteresis angle and the position angle, determine the number of first pulses that need to be compensated and adjusted for the phase of the frequency-doubled position signal; Based on the first number of pulses, the frequency-doubled position signal is adjusted to obtain a compensated position signal.

2. The flywheel motor rotor position monitoring method according to claim 1, characterized in that, Before determining the hysteresis angle of the hysteresis position corresponding to the first position monitoring signal relative to the actual position of the motor rotor based on the first rotational speed and a preset hysteresis coefficient, the method further includes: The back EMF data of the motor at multiple different preset second speeds of the flywheel are obtained, as well as the second position monitoring signal of the motor rotor collected by the corresponding photoelectric sensor; For each second rotational speed, the back EMF pulse signal corresponding to the second rotational speed is determined based on the back EMF data corresponding to that second rotational speed; the angle difference of the motor rotor at that second rotational speed is calculated based on the back EMF pulse signal corresponding to the second rotational speed and the second position monitoring signal. The hysteresis coefficient of the motor rotor is determined based on each second rotational speed and its corresponding angle difference.

3. The flywheel motor rotor position monitoring method according to claim 1, characterized in that, The step of adjusting the frequency-doubled position signal based on the first pulse number to obtain the compensated position signal includes: Based on the preset multiple, determine the number of frequency-multiplying pulses of the frequency-multiplying position signal corresponding to one pulse of the first position monitoring signal; Calculate the actual number of second pulses counted during the phase shift process based on the number of frequency doubling pulses and the number of first pulses; When the rising edge of the current cycle in the first position monitoring signal is detected, pulse counting of the frequency-doubled position signal begins; and the rising edge when the pulse count reaches the second pulse number is determined as the compensation rising edge of the next cycle in the compensation position signal; and the compensation falling edge corresponding to the compensation rising edge in the compensation position signal is determined. The compensation position signal is obtained based on the compensation rising edge and the compensation falling edge.

4. The flywheel motor rotor position monitoring method according to any one of claims 1 to 3, characterized in that, The step of frequency multiplication of the first position monitoring signal to obtain a frequency-multiplied position signal corresponding to the first position monitoring signal includes: The first position monitoring signal is subjected to phase-locked loop and frequency multiplier processing using a preset phase-locked loop and frequency multiplier to obtain a frequency-multiplied position signal corresponding to the first position monitoring signal.

5. The flywheel motor rotor position monitoring method according to any one of claims 1 to 3, characterized in that, Obtaining the first rotational speed of the motor rotor includes: The first rotational speed of the motor rotor is calculated based on the frequency of the first position monitoring signal.

6. A flywheel motor rotor position monitoring device, characterized in that, include: The acquisition module is used to acquire the first position monitoring signal of the motor rotor in the flywheel and the first rotational speed of the motor rotor collected by the photoelectric sensor; A frequency multiplier module is used to perform frequency multiplication processing on the first position monitoring signal to obtain a frequency multiplier position signal corresponding to the first position monitoring signal; wherein the frequency of the frequency multiplier position signal is a preset multiple of the frequency of the first position monitoring signal; A phase-shifting module is used to perform phase-shifting compensation on the frequency-doubled position signal according to the first rotational speed to obtain a compensated position signal; The determining module is used to determine the position of the motor rotor based on the compensated position signal; The phase shifting module is specifically used for: Based on the first rotational speed and the preset hysteresis coefficient, determine the hysteresis angle of the hysteresis position corresponding to the first position monitoring signal relative to the actual position of the motor rotor; Based on the preset multiple, determine the position angle of the motor rotor corresponding to a single pulse in the frequency multiplication position signal; Based on the hysteresis angle and the position angle, determine the number of first pulses that need to be compensated and adjusted for the phase of the frequency-doubled position signal; Based on the first number of pulses, the frequency-doubled position signal is adjusted to obtain a compensated position signal.

7. A flywheel energy storage system, characterized in that, It includes a motor rotor, a photoelectric sensor, and a position monitoring device, wherein the position monitoring device is used to implement the method as described in any one of claims 1 to 5.

8. 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 5.

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