A method, apparatus, and motor system for detecting the resonant frequency of an electric motor.

Abstract

This invention relates to the field of mechanical control technology, and in particular to a method, apparatus, and motor system for detecting the resonant frequency of a motor. The method includes: testing the motor with a plurality of first pulses of increasing amplitude to obtain a plurality of first test images; obtaining the fluctuation frequency and critical frequency of the first test images; determining an adjustment value and a test frequency based on the fluctuation frequency and critical frequency of all the first test images; testing the motor with a plurality of second pulses of decreasing amplitude based on the adjustment value to obtain a plurality of second test images; updating the test frequency and adjustment value based on the plurality of second test images; if the adjustment value is not 0, repeating the setting of the second pulses and updating the adjustment value until the adjustment value is 0; otherwise, setting test pulses according to the test frequency; and testing the motor using the test pulses. This invention solves the problem of inaccurate detection of the resonant frequency due to inappropriate selection of test pulses.

Description

Technical Field

[0001] This invention relates to the field of mechanical control technology, and in particular to a method, apparatus and motor system for detecting the resonant frequency of a motor. Background Technology

[0002] Mechanical resonance refers to the physical phenomenon where the amplitude of a mechanical system increases significantly when the excitation frequency approaches its natural frequency. Mechanical resonance in motor systems can cause abnormal phenomena such as shaking and noise. Currently, there are two solutions for mechanical resonance in motor systems: one is an active suppression method that injects a small signal opposite to the resonance frequency into the motor current to generate a torque that counteracts the vibration; the other is a passive avoidance method that sets a "no-go zone" in the controller, allowing the motor to quickly and smoothly skip the resonance speed range. Both methods require detection of the motor's resonance frequency.

[0003] One current method for detecting the resonant frequency of a motor is to send a set of fixed pulses to the motor, acquire the phase current signal, and analyze the phase current signal to obtain the resonant frequency.

[0004] The pulse used is determined based on the motor's marked parameters, which is a theoretical value. Therefore, the obtained resonant frequency is also a theoretical value and is subject to certain deviations. Moreover, as the motor ages with use, the resonant frequency will shift. If the original pulse is still used for testing at this time, the obtained resonant frequency will be inaccurate. This indicates a problem where inappropriate selection of test pulses leads to inaccurate detection of the resonant frequency. Summary of the Invention

[0005] Therefore, it is necessary to provide a method, device, and motor system for detecting the resonant frequency of a motor to address the above-mentioned problems.

[0006] This invention is implemented as follows: a method for detecting the resonant frequency of a motor, the method comprising:

[0007] S101, set several first pulses with increasing amplitude to test the motor, obtain the three-phase output current of the motor driver and obtain the spectrum of the three-phase output current, use the spectrum as the first test image corresponding to the first pulse, and obtain several first test images.

[0008] S102, For each first test image, obtain the fluctuation frequency and critical frequency of the first test image based on the first test image;

[0009] S103, determine the adjustment value and test frequency based on the fluctuation frequency and critical frequency of all the first test images;

[0010] S104, sets several second pulses with decreasing amplitudes according to the adjustment value;

[0011] S105, the motor is tested using the second pulse to obtain several second test images, and the test frequency and adjustment value are updated based on the several second test images;

[0012] S106, Determine if the adjustment value is 0. If not, repeat steps S104-S105 until the adjustment value is 0. If yes, set the test pulse according to the test frequency.

[0013] S107 uses test pulses to test the motor and thus obtain the motor's resonant frequency.

[0014] In one embodiment, the present invention provides a device for detecting the resonant frequency of a motor, the device comprising:

[0015] The first setting module is used to set several first pulses with increasing amplitude to test the motor and obtain several first test images;

[0016] The first processing module is used to obtain the fluctuation frequency and critical frequency of each first test image based on the first test image.

[0017] The first result module is used to determine the adjustment value and test frequency based on the fluctuation frequency and critical frequency of all the first test images;

[0018] The second setting module is used to set several second pulses with decreasing amplitudes according to the adjustment value;

[0019] The second processing module is used to test the motor with the second pulse, obtain several second test images, and update the test frequency and adjustment value based on the several second test images;

[0020] The second result module is used to determine whether the adjustment value is 0. If not, the second setting module and the second processing module are repeated until the adjustment value is 0. If it is, the test pulse is set according to the test frequency.

[0021] The final test module is used to test the motor with test pulses to obtain the motor's resonant frequency.

[0022] In one embodiment, the present invention provides a motor system, the motor system including a motor body, a sensor module and a control module;

[0023] The sensor module is located at the three-phase output terminal of the motor driver in the motor body and is used to acquire the sampled value of the three-phase current.

[0024] The control module is connected to the motor body and is used to execute the steps of the above-described method for detecting the motor resonance frequency.

[0025] This invention provides a method for detecting the resonant frequency of a motor. The method involves testing the motor with a plurality of first pulses of increasing amplitude to obtain a plurality of first test images. For each first test image, the fluctuation frequency and critical frequency of that first test image are obtained. An adjustment value and a test frequency are determined based on the fluctuation frequency and critical frequency of all the first test images. A plurality of second pulses of decreasing amplitude are set according to the adjustment value. The motor is tested using the second pulses to obtain a plurality of second test images, and the test frequency and adjustment value are updated based on the plurality of second test images. It is determined whether the adjustment value is 0. If not, the second pulses are repeatedly set and the test frequency and adjustment value are updated until the adjustment value is 0. If so, a test pulse is set according to the test frequency. The motor is then tested using the test pulses to obtain the resonant frequency of the motor. This method first uses a first pulse with a large amplitude difference to test the motor, and then gradually narrows the range of the test frequency by setting several second pulses with decreasing amplitudes to test the motor. When the adjustment value is 0, the range of the test frequency has been reduced to the minimum, so the test frequency obtained is more accurate. The test pulse set according to the test frequency can more accurately test the resonant frequency of the motor, which solves the problem of inaccurate resonant frequency detection caused by inappropriate test pulse selection. Attached Figure Description

[0026] Figure 1 This is a flowchart of a method for detecting the resonant frequency of a motor in one embodiment;

[0027] Figure 2 This is a structural block diagram of a device for detecting the resonant frequency of a motor in one embodiment;

[0028] Figure 3 This is a structural block diagram of a motor system in one embodiment;

[0029] Figure 4 This is a block diagram of the internal structure of the control module in one embodiment. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] It is understood that the terms "first," "second," etc., used in this invention may be used to describe various elements herein, but unless specifically stated otherwise, these elements are not limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of this invention, a first script may be referred to as a second script, and similarly, a second script may be referred to as a first script.

[0032] like Figure 1 As shown, in one embodiment, a method for detecting the resonant frequency of a motor is proposed, which may specifically include the following steps:

[0033] S101, set several first pulses with increasing amplitude to test the motor, obtain the three-phase output current of the motor driver and obtain the spectrum of the three-phase output current, use the spectrum as the first test image corresponding to the first pulse, and obtain several first test images.

[0034] S102, For each first test image, obtain the fluctuation frequency and critical frequency of the first test image based on the first test image;

[0035] S103, determine the adjustment value and test frequency based on the fluctuation frequency and critical frequency of all the first test images;

[0036] S104, sets several second pulses with decreasing amplitudes according to the adjustment value;

[0037] S105, the motor is tested using the second pulse to obtain several second test images, and the test frequency and adjustment value are updated based on the several second test images;

[0038] S106, Determine if the adjustment value is 0. If not, repeat steps S104-S105 until the adjustment value is 0. If yes, set the test pulse according to the test frequency.

[0039] S107 uses test pulses to test the motor and thus obtain the motor's resonant frequency.

[0040] In this embodiment, among a plurality of first pulses with increasing amplitude, the amplitude difference between any two adjacent first pulses remains unchanged.

[0041] In this embodiment, two important parameters determine the pulse: amplitude and width. The goal of amplitude setting is to find the upper limit of the amplitude setting, that is, the maximum pulse corresponding to the test frequency. The goal of width setting is to ensure that the pulse contains a sufficiently wide range of frequency components to excite all resonant modes.

[0042] In this embodiment, the first test image is essentially a spectrogram.

[0043] In this embodiment, setting several first pulses with increasing amplitude to test the motor and obtain several first test images mainly involves two steps: one is setting the first pulse, and the other is using several first pulses with increasing amplitude to test the motor and obtain several first test images. The step of using second pulses to test the motor and obtain several second test images in S105 is the same as the step of using several first pulses with increasing amplitude to test the motor and obtain several first test images.

[0044] In this embodiment, the steps of updating the test frequency and adjustment value based on a plurality of second test images are the same as the steps of determining the adjustment value and test frequency in S102-S103.

[0045] In this embodiment, the first pulse and the second pulse are essentially both pulses, used only to distinguish pulses in different test steps. For example, pulses in S101 are all first pulses, pulses in S104 are all second pulses, and in S106, if S104 is repeated, it is a new second pulse. The data of the new second pulse is not shared with the data of the old second pulse. Similarly, the first test image and the second test image are the same.

[0046] In this embodiment, there may be multiple resonant frequencies, which is related to the number of structural components connected to the motor. When a suitable pulse is used to test the motor, all resonant frequencies will be displayed. However, in the process of determining the test pulse, it is not necessary to continue analyzing each resonant frequency; only one needs to be selected for analysis. In S107, the motor is tested using the test pulse, and a final test image is obtained. The final test image is also a spectrum diagram. The final test image contains multiple local maxima points. After filtering all the local maxima points, the frequencies corresponding to the remaining local maxima points are the resonant frequencies.

[0047] This invention provides a method for detecting the resonant frequency of a motor. The method involves testing the motor with a plurality of first pulses of increasing amplitude to obtain a plurality of first test images. For each first test image, the fluctuation frequency and critical frequency of that first test image are obtained. An adjustment value and a test frequency are determined based on the fluctuation frequency and critical frequency of all the first test images. A plurality of second pulses of decreasing amplitude are set according to the adjustment value. The motor is tested using the second pulses to obtain a plurality of second test images, and the test frequency and adjustment value are updated based on the plurality of second test images. It is determined whether the adjustment value is 0. If not, the second pulses are repeatedly set and the test frequency and adjustment value are updated until the adjustment value is 0. If so, a test pulse is set according to the test frequency. The motor is then tested using the test pulses to obtain the resonant frequency of the motor. This method first uses a first pulse with a large amplitude difference to test the motor, and then gradually narrows the range of the test frequency by setting several second pulses with decreasing amplitudes to test the motor. When the adjustment value is 0, the range of the test frequency has been reduced to the minimum, so the test frequency obtained is more accurate. The test pulse set according to the test frequency can more accurately test the resonant frequency of the motor, which solves the problem of inaccurate resonant frequency detection caused by inappropriate test pulse selection.

[0048] In one embodiment, the motor is tested using a plurality of first pulses with increasing amplitudes to obtain the three-phase output current of the motor driver and acquire the spectrum of the three-phase output current. The spectrum is used as the first test image corresponding to the first pulse to obtain a plurality of first test images, including:

[0049] Increment i by 1 each time, starting from 1. Obtain the amplitude of each first pulse;

[0050] Set the width of each first pulse to a preset width;

[0051] For each first pulse, the motor is tested using that first pulse to obtain the sampled value of the three-phase output current of the motor driver;

[0052] The spectrum is obtained by means of coordinate transformation and feature extraction based on the sampled values ​​of the three-phase output current of the motor driver. The spectrum is recorded as the first test image corresponding to the first pulse.

[0053] Where F0 is the initial amplitude, i is the sequence number of the first pulse, and k1 is the preset increment value.

[0054] In this embodiment, the pulse can be set and tested simultaneously. For example, after setting the first pulse, the first pulse is used for testing, and a second first pulse can be set during the testing process. Therefore, when setting the first pulse, the maximum value of i is uncertain, that is, the number of first pulses is unknown. When to stop setting the first pulse needs to be determined based on multiple first test images.

[0055] In this embodiment, since there are two important parameters determining the pulse: amplitude and width, setting the pulse essentially means setting these two parameters. The width should ideally be determined by the test frequency, but since the test frequency is not yet determined, a preset width can be used initially. The preset width can be set between 0.5 and 10 ms.

[0056] In this embodiment, the initial amplitude can start from 0.

[0057] In this embodiment, k1 is the amplitude difference between two adjacent first pulses. The first pulse is used to quickly anchor the range of the resonant frequency, so k1 can be set to a larger value. Assuming the rated current of the motor is 2A, k1 can be set to 0.2A, which is 1 / 10 of the rated current, so that the number of first pulses can be around 10.

[0058] In one embodiment, obtaining the fluctuation frequency and critical frequency of the first test image based on the first test image includes:

[0059] Traverse the spectrum of the first test image to identify all local maxima.

[0060] All local maxima are filtered out, and the largest local maximum is identified from the filtered local maxima. The largest local maximum is recorded as the critical amplitude, and the frequency corresponding to the critical amplitude is determined as the critical frequency.

[0061] Starting from the critical amplitude, obtain the amplitude preceding the critical amplitude;

[0062] Determine if the obtained amplitude is less than If yes, then the obtained amplitude is recorded as the first amplitude; otherwise, continue obtaining the previous amplitude until the obtained amplitude is less than the first amplitude. ;

[0063] Get the amplitude preceding the critical amplitude;

[0064] Determine if the obtained amplitude is greater than If not, then the frequency corresponding to the acquired amplitude is determined as the fluctuation frequency; if yes, then the acquired amplitude is updated to the first amplitude, and the process continues to acquire the previous amplitude until the acquired amplitude is less than or equal to... ;

[0065] Where a1 is the first preset ratio, f1 is the critical amplitude, a2 is the second preset ratio, and f2 is the first amplitude.

[0066] In this embodiment, the first test image is a spectrum graph, with frequency on the horizontal axis and amplitude on the vertical axis. Amplitude and the amplitude of the first pulse are two different definitions. When a motor is excited with pulses of different amplitudes, its rotational speed or vibration response amplitude is measured. Ideally, if within a certain amplitude range, the response amplitude increases proportionally to the pulse amplitude, and the resonant frequency remains constant, then this amplitude range is the "linear region." To determine the resonant frequency, the pulse amplitude needs to be within the "linear region." As mentioned in the previous steps, when setting the first pulse, the maximum value of i is uncertain, i.e., the number of first pulses is unknown. When to stop setting the first pulse needs to be determined based on multiple first test images. When the pulse amplitude exceeds the "linear region," setting the first pulse is immediately stopped.

[0067] In this embodiment, a local maximum is essentially an amplitude in the spectrum. Each local maximum corresponds to a resonant frequency. However, since the ultimate goal is to determine the test pulse, only one resonant frequency needs to be selected for analysis. Ideally, the resonant frequency remains constant, and since different resonant frequencies are spaced far apart, the largest local maximum can be used directly. Furthermore, because the response amplitude increases proportionally to the pulse amplitude, the largest local maximum will only become larger as the pulse length increases.

[0068] In this embodiment, the method for determining local maxima is a conventional technique and will not be elaborated here.

[0069] In this embodiment, ideally, the resonant frequency of the pulse entering the "linear region" remains unchanged. However, in reality, due to factors such as the internal circuitry and heat generation of the motor, different pulses will definitely fluctuate for the same resonant frequency.

[0070] In this embodiment, ideally, the largest local maximum point is a perfect single peak. However, in reality, a physical resonance mode may appear as multiple very close small peaks in the spectrum due to spectral leakage or nonlinearity. Therefore, the purpose of setting a1 is to filter out these small peaks. a1 can be set to 0.9 if the obtained amplitude is less than... This indicates that the amplitude differs significantly from the critical amplitude and is no longer within the range of the small peak. It can be understood as follows: ideally, the amplitude remains constant, then stretches considerably at the resonant frequency before falling back, forming a single peak. Therefore, a2 can be set to 0.1. If the obtained amplitude is less than or equal to... If the amplitudes do not change much, then this can be considered as the moment when the stretching is about to begin, and the frequency at this moment is determined as the oscillation frequency.

[0071] In one embodiment, the step of filtering all local maxima and determining the largest local maximum among the filtered local maxima includes:

[0072] Depend on The basic electrical frequency is obtained;

[0073] For each local maximum point, determine whether the frequency corresponding to the local maximum point is within the tolerance range of multiples of the basic electrical frequency. If so, remove the local maximum point.

[0074] The spectrum of the first test image is divided into several sub-bands according to a preset frequency.

[0075] Calculate the variance of the amplitude in each sub-band;

[0076] The sub-frequency band with the smallest variance is selected and denoted as the pure noise frequency band.

[0077] Calculate the average amplitude in the pure noise frequency band. and standard deviation ;

[0078] Depend on Noise peaks were obtained;

[0079] Determine whether the local maximum is greater than the noise peak; if not, remove the local maximum.

[0080] Identify the largest local maximum among the remaining local maximum points;

[0081] Where n is the real-time speed of the motor, p is the number of pole pairs of the motor, and b is the amplitude coefficient.

[0082] In this embodiment, the unfiltered local maxima include resonance peaks, electrical harmonic peaks, and random noise peaks. The step of determining whether the frequency corresponding to the local maximum is within the tolerance range of a multiple of the fundamental electrical frequency can eliminate electrical harmonic peaks. The step of determining whether the local maximum is greater than a noise peak can eliminate random noise peaks.

[0083] In this embodiment, the multiple of the basic electrical frequency refers to a number of times the basic electrical frequency. This multiple can be several times, including multiple frequencies. The fault tolerance range can be set to 99%-101%.

[0084] In this embodiment, the amplitude coefficient is typically set to any number between 3 and 5.

[0085] In this embodiment, in S107, the motor is tested using test pulses to obtain the resonant frequency of the motor and a spectrum diagram, i.e., the final test image. At this time, it is also necessary to filter the local maxima. The steps are the same as the filtering steps in the first test image. The difference is that the final test image does not need to determine the largest local maxima, because the filtered local maxima are each resonant frequency.

[0086] In this embodiment, since the steps of updating the test frequency and adjustment value based on several second test images are the same as the steps of determining the adjustment value and test frequency in S102-S103, it is also necessary to screen and select the largest local maximum point during the process of testing the motor with the second pulse.

[0087] In one embodiment, obtaining the fluctuation frequency and critical frequency of the first test image based on the first test image further includes:

[0088] S501, determine whether the critical frequency of the first test image corresponding to the latest first preset number of first pulses is increasing or decreasing. If so, stop using the first pulse to test the motor.

[0089] S502, if the critical frequency of the first test image corresponding to the latest first preset number of first pulses does not increase or decrease, then repeat S501 until the critical frequency of the first test image corresponding to the latest first preset number of first pulses increases or decreases.

[0090] In this embodiment, when setting the first pulse as mentioned in the previous steps, the maximum value of i is uncertain, i.e., the number of first pulses is unknown. When to stop setting the first pulse needs to be determined based on multiple first test images. When the pulse amplitude exceeds the "linear region," setting the first pulse is immediately stopped. The judgment condition is S501. If the pulse amplitude exceeds the "linear region," then the resonant frequency will be prepared to increase or decrease.

[0091] In this embodiment, the first preset quantity can be set to 3.

[0092] In this embodiment, although the steps of updating the test frequency and adjustment value according to several second test images are the same as the steps of determining the adjustment value and test frequency in S102-S103, the setting of the first pulse is from small to large, but the setting of the second pulse is from large to small. The upper limit of the first pulse is determined by S501, but the upper limit of the second pulse is determined at the beginning. Therefore, in the process of testing the motor with the second pulse, it is not necessary to perform steps similar to S501.

[0093] In one embodiment, determining the adjustment value and test frequency based on the fluctuation frequency and critical frequency of all the first test images includes:

[0094] S601, starting from the first first test image, determine whether the critical frequency of the first test image corresponding to the second preset number of first pulses tends to be stable. If so, remove the first test image corresponding to the first pulse before the second preset number of first pulses.

[0095] S602, if the critical frequency of the first test image corresponding to the second preset number of first pulses does not tend to stabilize, then the first first test image is removed and S601 is executed.

[0096] S603, determine the number m of the first test images;

[0097] S603, among all the first test images, obtain the first test image A with the smallest fluctuation frequency and the first test image B with the largest critical frequency;

[0098] S604, by Obtain the adjustment value;

[0099] S605, the critical frequency that appears most frequently in all the first test images is determined as the test frequency;

[0100] Among them, F A F represents the amplitude of the first pulse corresponding to the first test image A. B The amplitude of the first pulse corresponding to the first test image B.

[0101] In this embodiment, if the first test image when the first pulse is stopped from testing the motor corresponds to the upper limit of the "linear region," then S601-S602 aims to find the lower limit of the "linear region." Before the pulse enters the "linear region," the pulse amplitude is too small, and the resonant frequency may not be detected. Even if the resonant frequency is detected, the deviation is significant. Determining whether the critical frequency of the first test image corresponding to a second preset number of first pulses tends to stabilize can be achieved by checking if the difference between the second preset number of critical frequencies is within the error range of the average value of the second preset number of critical frequencies. After entering the linear region, the critical frequency should fluctuate on a horizontal line. The error range can be set to 95%-105%.

[0102] In this embodiment, the second preset quantity can be set to 3.

[0103] In this embodiment, in S603, the number m of the first test images is determined. At this time, the upper and lower limits of the "linear region" have been determined, that is, the first test images have been screened and the setting of the first pulse has been stopped.

[0104] In this embodiment, if the adjustment value is 0, since m is not 0, it is... When the value is 0, the first test image A and the first test image B are the same image. As the range decreases, the percentage of the first test image A and the first test image B being the same image increases significantly.

[0105] In one embodiment, setting a plurality of second pulses with decreasing amplitudes according to the adjustment value includes:

[0106] S701, determine whether the adjustment value has been updated. If yes, set the amplitude of the last second pulse as the maximum amplitude F1 and clear all second pulses. If no, set the amplitude of the last first pulse as the maximum amplitude F1.

[0107] S702, set the initial value of j to 1;

[0108] S703, by Obtain the amplitude of each second pulse;

[0109] S704, determine whether the amplitude of the latest second pulse is less than the minimum amplitude of the first pulse corresponding to the first test image; if so, stop setting the second pulse.

[0110] S705, if the amplitude of the latest second pulse is greater than or equal to the minimum amplitude in the first pulse corresponding to the first test image, then j is incremented by 1, and S703-S704 are executed.

[0111] S706, set the width of each second pulse to a preset width;

[0112] Where j is the sequence number of the second pulse, and c is the adjustment value.

[0113] In this embodiment, in S701, if the adjustment value is not updated, there are two possibilities: First, it is still in the first pulse test stage, at which point no adjustment value has been generated; second, it is still in the first second pulse test stage, at which point the test is not yet complete, and no new adjustment value has been generated for updating. In the first case, the second pulse needs to be set next. Since this second pulse belongs to the first second pulse, the amplitude of the last first pulse is determined as the maximum amplitude F1. In the second case, the second pulse to be set next is not the first second pulse, but possibly the second or third second pulse. In this case, the amplitude of the last second pulse is determined as the maximum amplitude F1.

[0114] In this embodiment, since the upper and lower limits of the "linear region" have been determined by the first pulse, the lower limit is the amplitude of the first pulse entering the linear region, which is the minimum amplitude of the first pulse corresponding to the first test image. This generally does not change, while the upper limit gradually decreases as the number of pulse groups is determined. This achieves the purpose of gradually narrowing the range of the resonant frequency. Therefore, the second pulse is set by decreasing amplitude. Of course, in S704, the amplitude of the latest second pulse can also be used as a judgment condition to determine whether it is less than the minimum amplitude of the second pulse corresponding to the previous second test image. In this way, if the lower limit of the "linear region" obtained by the first pulse increases, it can be updated synchronously.

[0115] In this embodiment, for each second pulse, several second pulses with decreasing amplitudes are set according to the adjustment value. This is called setting one second pulse, which contains multiple second pulses. Before setting the next second pulse, the previous second pulse needs to be cleared, which is a step in S701. The first pulse only needs to be set once, so it is not necessary to clear it.

[0116] In this embodiment, the width of the second pulse is set to be the same as the width of the first pulse.

[0117] In one embodiment, setting the test pulse according to the test frequency includes:

[0118] Determine the second test image C corresponding to the second pulse with the largest amplitude from the second test images corresponding to the test frequency;

[0119] Depend on Obtain the amplitude of the test pulse;

[0120] Set the width of the test pulse to less than Integer values;

[0121] Where k2 is the preset safety factor, F x Let N be the amplitude of the second pulse corresponding to the second test image C, and let N be the test frequency.

[0122] In this embodiment, k2 can be set to 0.7.

[0123] like Figure 2 As shown, in one embodiment, a device for detecting the resonant frequency of a motor is provided, which may specifically include:

[0124] The first setting module is used to set several first pulses with increasing amplitude to test the motor and obtain several first test images;

[0125] The first processing module is used to obtain the fluctuation frequency and critical frequency of each first test image based on the first test image.

[0126] The first result module is used to determine the adjustment value and test frequency based on the fluctuation frequency and critical frequency of all the first test images;

[0127] The second setting module is used to set several second pulses with decreasing amplitudes according to the adjustment value;

[0128] The second processing module is used to test the motor with the second pulse, obtain several second test images, and update the test frequency and adjustment value based on the several second test images;

[0129] The second result module is used to determine whether the adjustment value is 0. If not, the second setting module and the second processing module are repeated until the adjustment value is 0. If it is, the test pulse is set according to the test frequency.

[0130] The final test module is used to test the motor with test pulses to obtain the motor's resonant frequency.

[0131] In this embodiment, the modules of the motor resonance frequency detection device are modularized from the method of the present invention. For a detailed explanation of each module, please refer to the corresponding content in the method section of the present invention. The embodiments of the present invention will not be repeated here.

[0132] like Figure 3 As shown, in one embodiment, a motor system is provided, which may include: a motor body, a sensor module, and a control module;

[0133] The sensor module is located at the three-phase output terminal of the motor driver in the motor body and is used to acquire the sampled value of the three-phase current.

[0134] The control module is connected to the motor body and is used to execute the steps of the above-described method for detecting the motor resonance frequency.

[0135] In this embodiment, the sensor module is a current sensor.

[0136] This invention provides a motor system that tests a motor by setting a plurality of first pulses with increasing amplitude to obtain a plurality of first test images. For each first test image, the fluctuation frequency and critical frequency of the first test image are obtained. An adjustment value and a test frequency are determined based on the fluctuation frequency and critical frequency of all the first test images. A plurality of second pulses with decreasing amplitude are set according to the adjustment value. The motor is tested using the second pulses to obtain a plurality of second test images, and the test frequency and adjustment value are updated according to the plurality of second test images. It is determined whether the adjustment value is 0. If not, the second pulses are repeatedly set and the test frequency and adjustment value are updated until the adjustment value is 0. If so, the test pulses are set according to the test frequency. The motor is tested using the test pulses to obtain the resonant frequency of the motor. This method first uses a first pulse with a large amplitude difference to test the motor, and then gradually narrows the range of the test frequency by setting several second pulses with decreasing amplitudes to test the motor. When the adjustment value is 0, the range of the test frequency has been reduced to the minimum, so the test frequency obtained is more accurate. The test pulse set according to the test frequency can more accurately test the resonant frequency of the motor, which solves the problem of inaccurate resonant frequency detection caused by inappropriate test pulse selection.

[0137] Figure 4 An internal structural diagram of the control module in one embodiment is shown. Figure 4 As shown, the control module includes a processor, a memory, a network interface, an input device, and a display screen connected via a system bus. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium of the control module stores an operating system and may also store a computer program. When executed by the processor, this computer program enables the processor to implement the motor resonance frequency detection method provided in this embodiment of the invention. The internal memory may also store a computer program, which, when executed by the processor, enables the processor to execute the motor resonance frequency detection method provided in this embodiment of the invention.

[0138] Those skilled in the art will understand that Figure 4 The structure shown is merely a block diagram of a portion of the structure related to the present invention and does not constitute a limitation on the control module to which the present invention is applied. The specific control module may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0139] In one embodiment, the motor resonance frequency detection device provided by this invention can be implemented as a computer program, which can be implemented in the form of, for example... Figure 4The control module shown operates on this system. The control module's memory can store the various program modules that make up the detection device for the motor's resonant frequency, for example... Figure 2 The diagram shows a first setting module, a first processing module, a first result module, a second setting module, a second processing module, a second result module, and a final test module. The computer program comprised of these modules causes the processor to execute the steps of a method for detecting the resonant frequency of a motor, as described in the various embodiments of the present invention.

[0140] For example, Figure 4 The control module shown can be used as follows Figure 2 In the motor resonance frequency detection device shown, the first setting module executes step S101; the control module can execute step S102 through the first processing module; the control module can execute step S103 through the first result module; the control module can execute step S104 through the second setting module; the control module can execute step S105 through the second processing module; the control module can execute step S106 through the second result module; and the control module can execute step S107 through the final test module.

[0141] In one embodiment, a control module is provided, the control module including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to perform the following steps:

[0142] S101, set several first pulses with increasing amplitude to test the motor, obtain the three-phase output current of the motor driver and obtain the spectrum of the three-phase output current, use the spectrum as the first test image corresponding to the first pulse, and obtain several first test images.

[0143] S102, For each first test image, obtain the fluctuation frequency and critical frequency of the first test image based on the first test image;

[0144] S103, determine the adjustment value and test frequency based on the fluctuation frequency and critical frequency of all the first test images;

[0145] S104, sets several second pulses with decreasing amplitudes according to the adjustment value;

[0146] S105, the motor is tested using the second pulse to obtain several second test images, and the test frequency and adjustment value are updated based on the several second test images;

[0147] S106, Determine if the adjustment value is 0. If not, repeat steps S104-S105 until the adjustment value is 0. If yes, set the test pulse according to the test frequency.

[0148] S107 uses test pulses to test the motor and thus obtain the motor's resonant frequency.

[0149] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, causes the processor to perform the following steps:

[0150] S101, set several first pulses with increasing amplitude to test the motor, obtain the three-phase output current of the motor driver and obtain the spectrum of the three-phase output current, use the spectrum as the first test image corresponding to the first pulse, and obtain several first test images.

[0151] S102, For each first test image, obtain the fluctuation frequency and critical frequency of the first test image based on the first test image;

[0152] S103, determine the adjustment value and test frequency based on the fluctuation frequency and critical frequency of all the first test images;

[0153] S104, sets several second pulses with decreasing amplitudes according to the adjustment value;

[0154] S105, the motor is tested using the second pulse to obtain several second test images, and the test frequency and adjustment value are updated based on the several second test images;

[0155] S106, Determine if the adjustment value is 0. If not, repeat steps S104-S105 until the adjustment value is 0. If yes, set the test pulse according to the test frequency.

[0156] S107 uses test pulses to test the motor and thus obtain the motor's resonant frequency.

[0157] It should be understood that although the steps in the flowcharts of the various embodiments of the present invention are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the various embodiments may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least a portion of the sub-steps or stages of other steps.

[0158] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided by this invention can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0159] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0160] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method of detecting a resonance frequency of an electric machine, characterized in that, The motor resonance frequency detection method comprises: S101, a plurality of first pulses with increasing amplitudes are set to test the motor, three-phase output currents of the motor driver are obtained, and a frequency spectrum of the three-phase output currents is acquired, the frequency spectrum is taken as a first test image corresponding to the first pulse, and a plurality of first test images are obtained; S102, for each first test image, a fluctuation frequency and a critical frequency of the first test image are obtained according to the first test image, comprising: traversing the frequency spectrum of the first test image to determine all local maximum points; all local maximum points are screened, and the largest local maximum point is determined in the screened local maximum points, the largest local maximum point is recorded as a critical amplitude, and a frequency corresponding to the critical amplitude is determined as the critical frequency; the critical amplitude is taken as a starting point, and a previous amplitude of the critical amplitude is acquired; determining whether the obtained amplitude is smaller than , if yes, recording the obtained amplitude as the first amplitude, and if no, continuing to obtain the previous amplitude until the obtained amplitude is smaller than ; the previous amplitude of the critical amplitude is acquired; whether the obtained amplitude is greater than , if not, the frequency corresponding to the obtained amplitude is determined as the fluctuation frequency, if yes, the obtained amplitude is updated as the first amplitude, and the previous amplitude is continuously obtained until the obtained amplitude is less than or equal to ; wherein a1 is a first preset ratio, f1 is the critical amplitude, a2 is a second preset ratio, and f2 is the first amplitude; S103, an adjustment value and a test frequency are determined according to the fluctuation frequencies and the critical frequencies of all first test images, comprising: S601, starting from the first first test image, it is judged whether the critical frequencies of the first test images corresponding to a second preset number of first pulses tend to be stable, if yes, the first test image corresponding to the first pulse before the second preset number of first pulses is excluded; S602, if the critical frequencies of the first test images corresponding to the second preset number of first pulses do not tend to be stable, the first first test image is excluded, and S601 is executed; S603, the number m of first test images is determined; S603, the first test image A with the minimum fluctuation frequency and the first test image B with the maximum critical frequency are acquired in all first test images; S604, by obtaining an adjustment value; S605, the critical frequency appearing the most times in all first test images is determined as the test frequency; wherein F A is the amplitude of the first pulse corresponding to the first test image A, F B is the amplitude of the first pulse corresponding to the first test image B; S104, a plurality of second pulses with decreasing amplitudes are set according to the adjustment value; S105, the motor is tested by using the second pulses, a plurality of second test images are obtained, and the test frequency and the adjustment value are updated according to the plurality of second test images; S106, it is judged whether the adjustment value is 0, if not, steps S104-S105 are repeated until the adjustment value is 0, and if yes, a test pulse is set according to the test frequency; S107, the motor is tested by using the test pulse, and the resonance frequency of the motor is obtained.

2. The method of claim 1, wherein The motor is tested by using the plurality of first pulses with increasing amplitudes, the three-phase output currents of the motor driver are obtained, the frequency spectrum of the three-phase output currents is acquired, the frequency spectrum is taken as the first test image corresponding to the first pulse, and the plurality of first test images are obtained, comprising: incrementing i by 1 each time from 1, by obtaining the amplitude of each first pulse; the width of each first pulse is set as a preset width; for each first pulse, the motor is tested by using the first pulse, and the sampling value of the three-phase output currents of the motor driver is obtained; the frequency spectrum is obtained by coordinate transformation and feature extraction according to the sampling value of the three-phase output currents of the motor driver, and the frequency spectrum is recorded as the first test image corresponding to the first pulse; Wherein, F0 is the initial amplitude, i is the serial number of the first pulse, k1 is a preset increase value.

3. The method of claim 1, wherein the step of detecting the resonant frequency of the motor comprises the steps of: applying a voltage to the motor; measuring a current of the motor; and determining the resonant frequency of the motor based on the measured current. The screening of all local maximum points and the determination of the maximum local maximum point in the screened local maximum points comprise: By obtaining a base electrical frequency; For each local maximum point, it is judged whether the frequency corresponding to the local maximum point is within the fault tolerance range of the multiple of the basic electrical frequency, and if so, the local maximum point is removed; The spectrum of the first test image is divided into several sub-frequency bands according to a preset frequency; The variance of the amplitude in each sub-frequency band is calculated; The sub-frequency band with the minimum variance is selected as a pure noise frequency band; calculating the average of the amplitudes in the pure noise frequency band and the standard deviation ; obtained from obtained from It is judged whether the local maximum point is greater than a noise peak, and if not, the local maximum point is removed; The maximum local maximum point is determined from the remaining local maximum points; Wherein, n is the real-time speed of the motor, p is the pole pair number of the motor, and b is the amplitude coefficient.

4. The method of claim 1, wherein The determination of the fluctuation frequency and the critical frequency of the first test image according to the first test image further comprises: S501, it is judged whether the critical frequency of the first test image corresponding to the latest first preset number of first pulses is increasing or decreasing, and if so, the testing of the motor by the first pulses is stopped; S502, if the critical frequency of the first test image corresponding to the latest first preset number of first pulses is not increasing or decreasing, S501 is repeated until the critical frequency of the first test image corresponding to the latest first preset number of first pulses is increasing or decreasing.

5. The method of claim 1, wherein, The setting of a plurality of second pulses with decreasing amplitudes according to the adjustment value comprises: S701, it is judged whether the adjustment value is updated, and if so, the amplitude of the last second pulse is determined as the maximum amplitude F1, and all second pulses are removed, and if not, the amplitude of the last first pulse is determined as the maximum amplitude F1; S702, the initial value of j is set to 1; S703, by obtaining the amplitude of each second pulse; S704, it is judged whether the amplitude of the latest second pulse is less than the minimum amplitude in the first pulses corresponding to the first test image, and if so, the setting of the second pulse is stopped; S705, if the amplitude of the latest second pulse is greater than or equal to the minimum amplitude in the first pulses corresponding to the first test image, j is incremented by 1, and S703-S704 are executed; S706, the width of each second pulse is set to a preset width; Wherein, j is the serial number of the second pulse, and c is the adjustment value.

6. The method of claim 1, wherein, The setting of the test pulse according to the test frequency comprises: The second test image C corresponding to the second pulse with the maximum amplitude is determined from the second test image corresponding to the test frequency. from obtaining the amplitude of the test pulse; The width of the test pulse is set to be less than an integer value; wherein k2 is a preset safety factor, F x is the amplitude of the second pulse corresponding to the second test image C, and N is the test frequency.

7. An apparatus for detecting a resonance frequency of an electric machine for implementing the method for detecting a resonance frequency of an electric machine according to claim 1, characterized in that, The motor resonance frequency detection device comprises: A first setting module for setting a plurality of first pulses with increasing amplitudes to test the motor and obtain a plurality of first test images; A first processing module for, for each first test image, obtaining the fluctuation frequency and the critical frequency of the first test image according to the first test image; A first result module for determining the adjustment value and the test frequency according to the fluctuation frequencies and the critical frequencies of all first test images; A second setting module for setting a plurality of second pulses with decreasing amplitudes according to the adjustment value; The second processing module is configured to test the motor by using a second pulse to obtain a plurality of second test images, and update the test frequency and the adjustment value according to the plurality of second test images; The second result module is configured to determine whether the adjustment value is 0, if not, repeat the second setting module and the second processing module until the adjustment value is 0, and if yes, set the test pulse according to the test frequency; The final test module is configured to test the motor by using the test pulse to obtain the resonance frequency of the motor.

8. An electric motor system characterized by, The motor system comprises a motor body, a sensor module and a control module; The sensor module is arranged at three-phase output terminals of a motor driver of the motor body, and is configured to obtain sampling values of three-phase currents; The control module is connected with the motor body, and is configured to execute steps of the detection method of the resonance frequency of the motor according to any one of claims 1 to 6.

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