Propulsion motor rotor position observation method and system

Abstract

The invention relates to the technical field of motor rotor positioning, in particular to a propulsion motor rotor position observation method and system. And obtaining a current value sequence of each measuring point in the motor and a corresponding time interval sequence, analyzing the change characteristic of the current value and the difference of numerical values in the time interval sequence, and jointly determining the electromagnetic transaction coefficient of the motor rotor. The coefficient reflects the abnormal condition of the electromagnetic force of the rotor in the motor, and the larger the abnormality is, the larger the rotor positioning observation error is. And when the electromagnetic transaction coefficient exceeds a normal range, electromagnetic uniformity compensation is carried out to realize more accurate rotor positioning. Meanwhile, the time interval sequence is subjected to frequency domain analysis, periodic behaviors are revealed, a current time sequence interval is calculated, and a current signal subjected to electromagnetic uniformity compensation is constructed based on the frequency domain analysis. The reconstructed current signal can reflect the motion condition of the rotor in the motor more accurately, so that the rotor in the motor can be positioned more accurately.

Description

Technical Field

[0001] The present invention relates to the technical field of motor rotor positioning, and particularly relates to a method and system for observing the position of a propulsion motor rotor. Background Art

[0002] A propulsion motor generally refers to a motor used in a propulsion system, which is widely applied to the propulsion systems of various vehicles and devices, such as electric vehicles, ships, airplanes, drones, etc. Its main purpose is to provide driving force for the device. In an electric drive system, as a key component, the performance of the propulsion motor directly affects the operation efficiency and stability of the entire system. The position observation of the motor rotor is an important task in motor control, which is of great significance for achieving precise motor control, improving the system response speed and stability.

[0003] When the prior art locates the rotor in a motor, it usually judges the relative position of the rotor according to the current change at the measuring point. However, during the long-term operation of the motor, the electromagnetic force of the rotor in the motor will generate abnormal movements due to long-term operation, such as weakening or unevenness, which will lead to the delay of the current change. Therefore, if the delay of the current is not corrected and the current change is directly analyzed to locate the rotor, the position of the rotor cannot be accurately located. Summary of the Invention

[0004] In order to solve the technical problem that during the long-term operation of the motor, the electromagnetic force of the rotor in the motor will generate abnormal movements due to long-term operation, such as weakening or unevenness, which will lead to the delay of the current change. Therefore, if the delay of the current is not corrected and the current change is directly analyzed to locate the rotor, the position of the rotor cannot be accurately located, the purpose of the present invention is to provide a method and system for observing the position of a propulsion motor rotor, and the specific technical solutions adopted are as follows: Obtain the current value sequence at each measuring point in the motor, and the time interval sequence corresponding to the current value sequence; In each current value sequence, analyze the change fluctuation characteristics between the current values to determine the amplitude change characteristic value of the current; in the time interval sequence corresponding to each current value sequence, analyze the difference between the values to determine the delay change characteristic value of the time interval sequence; combine the amplitude change characteristic value and the delay change characteristic value to obtain the electromagnetic abnormal movement coefficient of the motor rotor at each measuring point; When the electromagnetic anomaly coefficient of the motor rotor at a certain measurement point is greater than a preset threshold, analyze the frequency-domain information in the time interval sequence corresponding to this measurement point, calculate the current time sequence interval; construct a current signal based on the current time sequence interval and the current value sequence corresponding to this measurement point; when the electromagnetic anomaly coefficient of the motor rotor at a certain measurement point is less than or equal to the preset threshold, use the current value sequence at this measurement point as the current signal; Locate the motor rotor according to the change of the current value in the current signals at all measurement points.

[0005] Furthermore, the method for obtaining the amplitude change characteristic value includes: Preset a rotor period, segment each current value sequence based on the rotor period to obtain period data segments; In each current value sequence, use the first period data segment as the reference data segment and the remaining period data segments as the comparison data segments; Take the difference between each current value in the reference data segment and the current value at the same position in each comparison data segment as the amplitude change factor; Take the sum value of all amplitude change factors between the reference data segment and each comparison data segment as the current change coefficient; Take the normalized value of the sum value of the current change coefficients between the reference data segment and all comparison data segments as the amplitude change characteristic value of the current.

[0006] Furthermore, the method for obtaining the delay change characteristic value includes: Segment the time interval sequence corresponding to each current value sequence based on the rotor period to obtain time interval data segments; In each time interval data segment, take the last value as the reference value, take the remaining all values as the comparison values, take the difference between the reference value and each comparison value as the time difference factor, and take the sum value of all time difference factors as the time difference coefficient; Take the normalized value of the sum value of the time difference coefficients corresponding to all time interval data segments as the delay change characteristic value of the time interval sequence.

[0007] Furthermore, the method for obtaining the electromagnetic anomaly coefficient includes: Preset a proportion coefficient; At each measurement point, take the product of the proportion coefficient and the amplitude change characteristic value corresponding to the current value sequence as the first anomaly factor; Take the product of the value obtained by performing a negative correlation mapping on the proportion coefficient and the delay change characteristic value of the time interval sequence corresponding to the current value sequence as the second anomaly factor; The normalized value of the sum of the first abnormal factor and the second abnormal factor is used as the electromagnetic abnormal coefficient of the motor rotor at each measuring point.

[0008] Further, the method for obtaining the current time sequence interval includes: Performing a discrete Fourier transform on the time interval sequence to obtain a frequency spectrum diagram; In the frequency spectrum diagram, calculate the mean value of the amplitudes of all frequencies as the amplitude mean value, and use the frequencies whose amplitudes are greater than or equal to the amplitude mean value as the target frequencies; Calculate the corresponding period values according to each target frequency, and use the mean value of all the period values as the current time sequence interval.

[0009] Further, constructing a current signal based on the current time sequence interval and the current value sequence corresponding to the measuring point includes: In terms of time sequence, arrange the current values in the current value sequence corresponding to the measuring point according to the current time sequence interval, so as to obtain a current signal.

[0010] Further, the method for obtaining the time interval sequence includes: In each current value sequence, use the time interval between every two adjacent current values as a value in the time interval sequence.

[0011] Further, positioning the motor rotor according to the change of the current values in the current signals at all measuring points includes: Perform edge detection on each current signal to obtain the moments of the current rising edge and the current falling edge as the edge moments; According to the position of each measuring point in the motor and the edge moments in the current signals at each measuring point, determine the position information of the motor rotor at each edge moment.

[0012] Further, the value range of the preset proportion coefficient is (0.5, 1).

[0013] A propulsion motor rotor position observation system includes a processor and a memory. At least one instruction, at least one program, a code set or an instruction set is stored in the memory. When at least one instruction, at least one program, the code set or the instruction set is loaded and executed by the processor, the steps of the propulsion motor rotor position observation method are implemented.

[0014] The present invention has the following beneficial effects: Inside the propulsion motor, current is generated due to electromagnetic effects, and thus the position of the motor rotor can be located based on the change of the current, which is used to achieve functions such as motor control. In the present invention, first, a sequence of current values at each measurement point in the motor is obtained. The change of the current values in this sequence can reflect the change characteristics of the electromagnetic field. Because during the long-term operation of the motor, demagnetization may occur, resulting in a weakening or unevenness of the electromagnetic force, and thus causing a delay in the change of the current. In order to analyze the delay characteristics of the current and facilitate the compensation of the electromagnetic uniformity, a sequence of time intervals corresponding to the sequence of current values is simultaneously obtained. Each value in this sequence represents the time interval between two adjacent current values in the sequence of current values. Given that current can only be detected under a certain intensity of electromagnetic effect, when the magnetic distribution is uneven, the change of the current in the sequence of current values will show obvious fluctuations, and there will also be a certain delay in the time interval when the current values appear. Therefore, the present invention analyzes the change characteristics of the current values in the sequence of current values and combines the differences between the values in the sequence of time intervals to jointly determine the electromagnetic anomaly coefficient of the motor rotor. The electromagnetic anomaly coefficient can reflect the abnormal situation of the electromagnetic force of the rotor inside the motor. The greater the anomaly, the greater the error in the positioning observation of the rotor will be. Therefore, when the electromagnetic anomaly coefficient exceeds the normal range, compensation for the electromagnetic uniformity needs to be carried out to facilitate more accurate rotor positioning. The values in the sequence of time intervals represent the time intervals when the current values appear. Therefore, performing frequency-domain analysis on it can reveal the periodic behavior in the sequence of time intervals, which is helpful for understanding the variation of the electromagnetic force. Therefore, by analyzing the frequency-domain information in the sequence of time intervals, the current time sequence interval can be calculated. At this time, the current time sequence interval is regarded as the time interval when the current value after electromagnetic uniformity compensation should appear. Therefore, a current signal can be constructed based on this time interval and the sequence of current values. The appearance time and change characteristics of the current values in the reconstructed current signal can more accurately reflect the movement of the rotor in the motor. Therefore, finally, based on the change of the current values in the current signals at all measurement points in the motor, the rotor in the motor can be positioned more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following-described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 FIG. is a flowchart of a method for observing the position of a propulsion motor rotor provided by an embodiment of the present invention; Figure 2The system block diagram of a propulsion motor rotor position observation system provided by an embodiment of the present invention; Figure 3 The schematic structural diagram of a propulsion motor rotor position observation system provided by an embodiment of the present invention. Detailed implementation manners

[0017] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following describes in detail a propulsion motor rotor position observation method and system proposed according to the present invention, its specific implementation manners, structures, features and effects in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0019] The following specifically describes the specific solutions of a propulsion motor rotor position observation method and system provided by the present invention in conjunction with the accompanying drawings.

[0020] Please refer to Figure 1 , which shows the method flowchart of a propulsion motor rotor position observation method provided by an embodiment of the present invention. The method includes the following steps: Step S1: Obtain the current value sequence at each measurement point in the motor, and the time interval sequence corresponding to the current value sequence.

[0021] In the electric drive system, the propulsion motor is a key component, and its performance directly affects the operation efficiency and stability of the entire system. The position observation of the motor rotor is an important task in motor control, which is of great significance for achieving precise motor control, improving the system response speed and stability, especially in brushless motors and permanent magnet synchronous motors.

[0022] During the long-term operation of the motor, due to the large volume and mass of the propulsion target, the motor is affected by factors such as inertia during operation. Long-term high-intensity work will cause the magnet to demagnetize, resulting in an imbalance in the magnetic distribution. Due to the weakened or uneven magnetism, the current amplitude and time of the high and low level signals detected by the Hall sensors installed at three different angles will deviate, affecting the accurate detection of the rotor position by the Hall sensors. Therefore, in the embodiments of the present invention, in order to improve the accuracy of rotor positioning, a current value sequence at each measurement point in the motor and a corresponding time interval sequence are obtained. By analyzing the change characteristics of the current values in the current value sequence and the differences in the values in the time interval sequence, the abnormal movement of the magnetism is further judged, so as to provide data support for subsequent rotor positioning.

[0023] Specifically, the method for obtaining the current value sequence includes: According to the structure of the motor, three Hall sensors are installed along the stator in the motor, and the interval is set to 120 electrical degrees, which is convenient for more accurately measuring different positions of the rotor. The gap between the Hall sensor and the rotor surface is generally set to 0.5-2 mm to ensure that the Hall sensor can accurately sense the magnetic field without being affected by mechanical vibration or other factors; the rotor of the motor is equipped with a permanent magnet. When the rotor rotates, the Hall sensor will sense the change in the magnetic field polarity of the rotor magnet. For example, when a north pole passes by the Hall sensor, the Hall sensor will output a high-level signal; when a south pole passes by, the Hall sensor will output a low-level signal. The Hall sensor generates a signal proportional to the change in the magnetic field strength by detecting the change in the rotor magnetic field: the signal collected by the sensor is converted from an analog signal to a digital signal through an A / D converter. Thus, a current value sequence at each Hall sensor position (measurement point) can be obtained.

[0024] After obtaining the current value sequence, in order to analyze the delay of the current value, a corresponding time interval sequence is further obtained according to the current value sequence.

[0025] Preferably, in an embodiment of the present invention, the method for obtaining the time interval sequence includes: In each current value sequence, the time interval between every two adjacent current values is used as a value in the time interval sequence. Thus, a time interval sequence corresponding to the current value sequence can be obtained. For example, if the current value sequence includes 4 current values, and the times corresponding to current values 1-4 are 1, 3, 7, 12 respectively, then the time interval sequence is (2, 4, 5).

[0026] It should be noted that in the embodiments of the present invention, the acquisition length of the current value sequence is set to 5 minutes, and the specific length can be adjusted according to the implementation scenario and is not limited herein.

[0027] Step S2: In each current value sequence, analyze the change and fluctuation characteristics between current values to determine the amplitude change characteristic value of the current; in the time interval sequence corresponding to each current value sequence, analyze the difference between values to determine the delay change characteristic value of the time interval sequence; combine the amplitude change characteristic value and the delay change characteristic value to obtain the electromagnetic abnormal movement coefficient of the motor rotor at each measuring point.

[0028] When the load of the propulsion motor rotor is high and it runs for a long time, the permanent magnet of its internal rotor will experience magnetic weakening or uneven magnetic distribution; when the magnetism weakens, in the Hall sensor, the electromagnetic effect shown will weaken, and the further obtained current value will decrease. At this time, reflected in the current value sequence, the current value will decrease by a certain proportion. Similarly, when the magnetic distribution is uneven, when the rotor reaches the Hall sensor, due to the uneven magnetic force distribution, the generated level value will be regarded as a high level or a low level only under a certain intensity of electromagnetic effect, that is, the rotor needs to complete several more steps to generate the corresponding electromagnetic effect, so as to be detected as a high level or a low level. And when the rotor completes several more steps, it will be manifested as a certain delay in the time interval sequence, that is, the value will increase. Because of the uneven electromagnetic force, the rotor pays a certain time cost to generate the electromagnetic effect and then generates the corresponding current. Therefore, in order to achieve precise positioning of the motor rotor in the embodiments of the present invention, it is necessary to analyze the current value sequence and the time interval sequence to determine whether there is electromagnetic abnormal movement in the motor, and then ensure the positioning accuracy of the motor rotor.

[0029] First, based on the foregoing analysis, it can be seen that when electromagnetic abnormal movement occurs, the amplitude of the current value will change in the current value sequence. Therefore, in the current value sequence, analyze the change and fluctuation characteristics between current values to determine the amplitude change characteristic value of the current, and use it as an index for subsequent evaluation of the electromagnetic abnormal movement of the motor rotor.

[0030] Preferably, in an embodiment of the present invention, the method for obtaining the amplitude change characteristic value includes: In order to make the fluctuation characteristics of the current value be more clearly characterized, in the embodiments of the present invention, a rotor period is preset, and each current value sequence is segmented based on the rotor period to obtain period data segments, and then the fluctuation difference of the current values between the period data segments is analyzed to reflect the amplitude change characteristic of the current.

[0031] In each current value sequence, due to electromagnetic abnormal movement (specifically, demagnetization or uneven magnetic distribution in the embodiments of the present invention), the amplitude of the current value will become smaller over time. Therefore, the first period data segment is used as the reference data segment, and the remaining period data segments are used as comparison data segments. Subsequently, the amplitude difference between the current values in the reference data segment and the current values in the comparison data segments is compared to evaluate the amplitude change characteristic of the current.

[0032] In the reference data segment and each comparison data segment, the difference between the current values at the same position is specifically each current value in the reference data segment minus the current value at the same position in the comparison data segment. This difference is used as the amplitude variation factor. When the amplitude variation factor is positive and the larger it is, it proves that the amplitude of the current value generated by the electromagnetic effect is decreasing at this time. Then the higher the amplitude variability is, it is regarded that the electromagnetic force in the rotor shows a weakening trend. Then, the sum of all the amplitude variation factors of the reference data segment and each comparison data segment is used as the current variation coefficient. Similarly, the larger the variation coefficient is, the greater the amplitude variation of the current is, and the higher the possibility of electromagnetic abnormal movement is.

[0033] So far, each of the reference data segment and each comparison data segment has a variation coefficient. All the variation coefficients can be synthesized, that is, calculate the sum of all the current variation coefficients, and the value obtained by normalizing this sum is used as the amplitude variation characteristic value of the current. The larger the amplitude variation characteristic value of the current is, the more it indicates that the electromagnetic effect has weakened and electromagnetic abnormal movement has occurred. The normalization method here can adopt function.

[0034] It should be noted that in the embodiment of the present invention, rotating the rotor 20 circles is regarded as a rotor period, or a fixed time interval, such as 30s, can be used as a rotor period. In this embodiment of the present invention, the method of using 30s as a rotor period is adopted; since current values are not generated every time the rotor passes through the Hall sensor, the number of current values in different periodic data segments may be different. Therefore, when calculating the difference between the current values at the same position in the reference data segment and the comparison data segment, the number of current values in the reference data segment is used as the standard. If the number of current values in the comparison data segment is greater than the number of current values in the reference data segment, the extra current values in the comparison data segment do not participate in the calculation; if the number in the comparison data segment is less than the number of current values in the reference data segment, 0 is used to supplement in the comparison data segment or the average value of the current values in the comparison data segment is used for supplementation. In this embodiment of the present invention, the method of average value supplementation is adopted.

[0035] After analyzing the change and fluctuation characteristics of the current values in the current value sequence and obtaining an index characterizing the electromagnetic abnormal movement of the motor rotor, based on the foregoing analysis, it can be known that when electromagnetic abnormal movement occurs, the rotor needs to pay a certain time cost before the electromagnetic effect occurs. Therefore, the time interval for generating current values will change significantly. Therefore, the difference between the values can continue to be analyzed in the time interval sequence, and the delay variation characteristic value of the time interval sequence is calculated as another index for evaluating the electromagnetic abnormal movement of the motor rotor.

[0036] Preferably, in an embodiment of the present invention, the method for obtaining the delay variation characteristic value includes: In the same way as the method for dividing the current value sequence, based on the rotor period, the time interval sequence corresponding to each current value sequence is segmented to obtain time interval data segments. Then, in each time interval data segment, the differences between the values are analyzed to reflect the variation characteristics of the time interval.

[0037] Since electromagnetic anomalies (specifically referring to demagnetization phenomena or uneven magnetic distribution in the embodiments of the present invention) will cause time delays, the values in the time interval data segments will show an increasing trend. Therefore, in each time interval data segment, the last value is used as the reference value, and all the remaining values are used as comparison values. The difference between the reference value and each comparison value is calculated, and this difference is used as the time difference factor. The larger the positive time difference factor, the greater the delay of the rotor at this time, that is, the magnetic field in the rotor has weakened significantly or changed unevenly. Then, the sum value of all the time difference factors is used as the time difference coefficient. Similarly, the larger the time difference coefficient, the more uneven the distribution of the time intervals, and the more likely it is that the electromagnetic effect has weakened or shifted.

[0038] So far, each time interval data segment has a time difference coefficient. The time difference coefficients corresponding to all the time interval data segments can be synthesized, that is, the sum value of all the time difference coefficients is calculated, and the value obtained after normalizing this sum value is used as the delay variation characteristic value of the time interval sequence. The larger the delay variation characteristic value, the more the electromagnetic effect has weakened, and the higher the possibility of generating electromagnetic anomalies. The normalization method here can adopt function.

[0039] Here, an example is given to illustrate the method for dividing the current value sequence and the time interval sequence: Suppose the moments corresponding to current values 1 - 9 in the current value sequence are 1, 3, 6, 9, 14, 18, 23, 28, 34 respectively. Then the time interval sequence corresponding to this current value sequence is (2, 3, 3, 5, 4, 5, 5, 6). If the rotor period is set to 20s, then the period data segments obtained by dividing the current value sequence are (current value 1, current value 2, current value 3, current value 4, current value 5, current value 6), (current value 7, current value 8, current value 9). The time interval data segments obtained by dividing the time interval sequence corresponding to the current value sequence are (2, 3, 3, 5, 4) corresponding to (current value 1, current value 2, current value 3, current value 4, current value 5, current value 6), and (5, 6) corresponding to (current value 7, current value 8, current value 9).

[0040] Based on the foregoing process, the amplitude change characteristic value corresponding to each current value sequence and the delay change characteristic value of the time interval sequence corresponding to each current value sequence can be calculated. These two values, as indicators for measuring the electromagnetic anomaly characteristics, can be combined to comprehensively evaluate the electromagnetic anomaly coefficient of the motor rotor at each measurement point.

[0041] Preferably, in an embodiment of the present invention, the method for obtaining the electromagnetic anomaly coefficient includes: Preset a proportion coefficient, which is used to balance the proportion between the amplitude change characteristic value and the delay change characteristic value. In the embodiment of the present invention, it is considered that when the electromagnetic force of the motor rotor changes or is abnormal, the most obvious change is the change in the current value generated by the Hall effect. Therefore, the value range of the proportion coefficient is set to (0.5, 1), aiming to amplify the fluctuation characteristics of the current amplitude.

[0042] Then, at each measurement point, the product of the proportion coefficient and the amplitude change characteristic value corresponding to the current value sequence is used as the first anomaly factor; the product of the value obtained by performing a negative correlation mapping on the proportion coefficient and the delay change characteristic value of the time interval sequence corresponding to the current value sequence is used as the second anomaly factor. The negative correlation mapping here uses the formula , where x represents the independent variable.

[0043] Finally, the value obtained by normalizing the sum of the first anomaly factor and the second anomaly factor is used as the electromagnetic anomaly coefficient of the motor rotor. At this time, the larger the electromagnetic anomaly coefficient, the more abnormal the electromagnetic force in the rotor. Then, if the position of the rotor is observed directly without correction, errors will occur. Normalization is a well-known technical means to those skilled in the art. The choice of the normalization function can be linear normalization or standard normalization, etc. The specific normalization method is not limited here.

[0044] Thus, through the foregoing steps, the electromagnetic anomaly coefficient of the rotor in the motor at each Hall sensor (each measurement point) can be obtained.

[0045] Step S3: When the electromagnetic anomaly coefficient of the motor rotor at a certain measurement point is greater than the preset threshold, analyze the frequency domain information in the corresponding time interval sequence of this measurement point, calculate the current time sequence interval; construct a current signal based on the current time sequence interval and the current value sequence corresponding to this measurement point; when the electromagnetic anomaly coefficient of the motor rotor at a certain measurement point is less than or equal to the preset threshold, use the current value sequence at this measurement point as the current signal.

[0046] Based on the analysis of the foregoing steps, it can be seen that when the electromagnetic anomaly coefficient of the motor rotor passing through a certain Hall sensor (measurement point) is larger, it indicates that the electromagnetic force is non-uniform. Then, during the rotation of the rotor, the lower the Hall effect corresponding to the part with a smaller electromagnetic force, the higher the delay of the generated current, and a certain threshold needs to be reached to generate a level and current. Therefore, for the position with a larger electromagnetic anomaly coefficient, it is necessary to analyze the delay characteristics to compensate for the degree of electromagnetic non-uniformity, so as to ensure the accuracy of subsequent positioning of the motor rotor. The values in the time interval sequence represent the time intervals when the current values appear. Therefore, performing frequency domain analysis on it can reveal the periodic behavior in the time interval sequence, which is helpful for understanding the variation of the electromagnetic force. Therefore, analyze the frequency domain information of the time interval sequence and calculate the current time sequence interval. At this time, the current time sequence interval is regarded as the time interval when the current appears after electromagnetic uniformity compensation. Therefore, a current signal can be constructed based on this time interval and the current value sequence. The appearance time and change characteristics of the current values in the reconstructed current signal can more accurately reflect the movement of the rotor in the motor.

[0047] First, screen the positions where the electromagnetic anomaly coefficient of the motor rotor exceeds the normal range. Compare the electromagnetic anomaly coefficient of the motor rotor at each Hall sensor in the motor with a preset threshold. When it is greater than the preset threshold, it is considered that the electromagnetic force is more abnormal and electromagnetic uniformity compensation is required. It should be noted that in the present invention, the preset threshold is set to 0.7, and the specific value can be adjusted according to the implementation scenario and is not limited herein.

[0048] Take the measurement points with electromagnetic anomaly coefficients greater than the preset threshold as target measurement points, and analyze the frequency domain information in the time interval sequence at the target measurement points to calculate the current time sequence interval.

[0049] Preferably, in an embodiment of the present invention, the method for obtaining the current time sequence interval includes: For each target measurement point, perform a discrete Fourier transform on the corresponding time interval sequence to obtain a frequency spectrum diagram. The frequency spectrum diagram can intuitively display the energy distribution at different frequencies, which helps to identify characteristic frequency components and thus reveals the distribution characteristics of the time interval in the frequency domain.

[0050] In the frequency spectrum diagram, the components with larger amplitudes often dominate and are regarded as the main characteristics. Therefore, calculate the mean value of the amplitudes of all frequencies as the amplitude mean value. The amplitude mean value, as the average level of the amplitudes of all frequencies in the frequency spectrum diagram, can be used as a screening criterion to screen out the main characteristics, and the frequencies with amplitudes greater than or equal to the amplitude mean value are used as target frequencies.

[0051] Then calculate the corresponding period value according to each target frequency, which characterizes the periodic characteristics in the time interval sequence. The calculation method is , where \(T\) represents the period value and \(f\) represents the target frequency.

[0052] Finally, the average value of the period values calculated for all target frequencies is used as the current timing interval. At this time, the current timing interval is regarded as the time interval between the current values after electromagnetic uniformity compensation, and it can more accurately characterize the change time interval characteristics of the current values at each target measurement point.

[0053] It should be noted that the discrete Fourier transform is a well-known technology, and the specific process will not be elaborated here.

[0054] For each target measurement point, after calculating the corresponding current timing interval, the current value sequence at this measurement point can be reconstructed using the current timing interval. Here, the reconstruction specifically refers to arranging the current values according to the current timing interval to obtain the current signal corresponding to this measurement point.

[0055] Preferably, in an embodiment of the present invention, the method for obtaining the current signal includes: In terms of timing, the current values in the current value sequence of each target measurement point are arranged according to the corresponding current timing interval to obtain the current signal, that is, the time interval between every two adjacent current values in the current value sequence is set to the calculated current timing interval.

[0056] So far, for the measurement points where the motor rotor has electromagnetic abnormal characteristics, the electromagnetic abnormal situation can be compensated according to the current value sequence and the time interval sequence. Therefore, for the measurement points with electromagnetic abnormal characteristics, the reconstructed current signal can more accurately reflect the position of the motor rotor.

[0057] In the embodiment of the present invention, when the electromagnetic abnormal coefficient of the motor rotor at a certain measurement point is less than or equal to the preset threshold, it indicates that the electromagnetic force is uniform. Then, the Hall effect generated during the rotation of the rotor is in a normal situation. Therefore, the current value sequence at this measurement point can be directly used for the positioning analysis of the motor rotor, so the current value sequence at this measurement point is used as the current signal.

[0058] Step S4: Locate the motor rotor according to the change of the current values in the current signals at all measurement points.

[0059] The Hall sensor is a magnetoelectric conversion device that uses the Hall effect to convert the change of the magnetic field into an electrical signal. In a motor, it is often used to detect the position of the motor rotor. Specifically, when the rotor rotates, the magnetic poles will pass by the Hall sensor in turn, thereby generating current changes on each Hall sensor, and these current changes can be used to determine the position of the rotor.

[0060] After the current value sequence at the measuring point with electromagnetic anomaly is corrected in step S3, the current signal can accurately reflect the position information of the motor rotor. Therefore, the position of the motor rotor can be observed more accurately according to the change of the current value in the current signals at all measuring points in the motor.

[0061] Preferably, in an embodiment of the present invention, positioning the motor rotor according to the change of the current value in the current signals at all measuring points includes: Performing edge detection on each current signal (such as based on wavelet transform, mathematical morphology, etc.), the mutation points in the current signal can be identified, and the moments of the current rising edge and the current falling edge are obtained as the edge moments. The edge moments correspond to the moments when the rotor poles pass by the Hall sensors.

[0062] According to the position of each measuring point (Hall sensor) in the motor and the edge moments in the current signals at each measuring point, the position information of the motor rotor at each edge moment is determined. For example, when the Hall sensor at measuring point 1 first has a current rise at edge moment 1, it is regarded that the magnetic pole of the motor rotor approaches the Hall sensor at measuring point 1 at edge moment 1. Subsequently, when the Hall sensor at measuring point 2 detects a rising edge at edge moment 3, it indicates that the motor rotor has rotated to measuring point 2. In this way, the rotation position of the motor rotor can be tracked, and the position information can be updated at each edge moment.

[0063] It should be noted that the process of performing edge detection on the signal to identify the rising edge and the falling edge is a well-known technology and will not be elaborated here.

[0064] In summary, inside the propulsion motor, current is generated due to electromagnetic effects, and thus the position of the motor rotor can be located based on the change of the current to achieve functions such as motor control. In the embodiment of the present invention, first, a sequence of current values at each measurement point in the motor is obtained. The change of the current values in this sequence can reflect the change characteristics of the electromagnetic field. Because during the long-term operation of the motor, demagnetization may occur, resulting in a weakening or unevenness of the electromagnetic force, and thus the change of the current shows a time delay. To analyze the time-delay characteristics of the current and facilitate the compensation of the electromagnetic uniformity, a time interval sequence corresponding to the current value sequence is simultaneously obtained. Each value in this sequence represents the time interval between two adjacent current values in the current value sequence. Given that current can only be detected under a certain intensity of electromagnetic effects, when the magnetic distribution is uneven, the change of the current in the current value sequence will show obvious fluctuations, and there will also be a certain time delay in the time interval when the current value appears. Therefore, in the embodiment of the present invention, the change characteristics of the current values in the current value sequence are analyzed, and combined with the difference between the values in the time interval sequence, the electromagnetic anomaly coefficient of the motor rotor is jointly determined. The electromagnetic anomaly coefficient can reflect the abnormal situation of the electromagnetic force of the rotor inside the motor. The greater the anomaly, the greater the error in the positioning observation of the rotor will be. Therefore, when the electromagnetic anomaly coefficient exceeds the normal range, electromagnetic uniformity compensation is required to achieve more accurate rotor positioning. The values in the time interval sequence represent the time intervals when the current values appear. Therefore, performing frequency-domain analysis on it can reveal the periodic behavior in the time interval sequence, which is helpful for understanding the variation of the electromagnetic force. Therefore, by analyzing the frequency-domain information in the time interval sequence, the current time sequence interval can be calculated. At this time, the current time sequence interval is regarded as the time interval when the current value after electromagnetic uniformity compensation should appear. Therefore, a current signal can be constructed based on this time interval and the current value sequence. The appearance time and change characteristics of the current values in the reconstructed current signal can more accurately reflect the movement of the rotor in the motor. Therefore, finally, based on the change of the current values in the current signals at all measurement points in the motor, the rotor in the motor can be positioned more accurately.

[0065] The embodiment of the present invention also provides a propulsion motor rotor position observation system. Please refer to Figure 2 , which shows a system block diagram, including a data acquisition module 201 for implementing step S1 in the above method embodiment; an electromagnetic anomaly analysis module 202 for implementing step S2 in the above method embodiment; a current signal construction module 203 for implementing step S3 in the above method embodiment; and a rotor positioning module 204 for implementing step S4 in the above method embodiment.

[0066] It should be noted that the system provided in the above embodiments is only illustrated by the division of the above function modules. In practical applications, the above functions can be allocated to different function modules according to needs, that is, the internal structure of the computer device is divided into different function modules to complete all or part of the functions described above. In addition, the embodiments of a propulsion motor rotor position observation system and a propulsion motor rotor position observation method provided in the above embodiments belong to the same concept. The specific implementation process is detailed in the method embodiments and will not be repeated here.

[0067] Please refer to Figure 3 , which shows a schematic structural diagram of a propulsion motor rotor position observation system provided by an embodiment of the present invention, including a processor 300, a memory 301, a bus 302, and a communication interface 303. The processor 300, the communication interface 303, and the memory 301 are connected through the bus 302. Among them, the memory 301 may include a high-speed random access memory. The bus 302 may be an ISA bus, a PCI bus, an EISA bus, etc. The processor 300 may be an integrated circuit chip with signal processing capabilities. At least one instruction, at least one program, a code set, or an instruction set is stored in the memory 301. When at least one instruction, at least one program, a code set, or an instruction set is loaded and executed by the processor, the steps in a propulsion motor rotor position observation method are implemented.

[0068] It should be noted that the above sequence of the embodiments of the present invention is only for description and does not represent the superiority or inferiority of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0069] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A propulsion motor rotor position observation method, characterized in that: The method comprises: Obtaining a current value sequence at each measuring point in the motor and a time interval sequence corresponding to the current value sequence; In each current value sequence, the change fluctuation characteristics between the current values ​​are analyzed to determine the current amplitude change characteristic value; in the time interval sequence corresponding to each current value sequence, the difference between the values ​​is analyzed to determine the delay change characteristic value of the time interval sequence; the electromagnetic anomaly coefficient of the motor rotor at each measuring point is obtained by combining the amplitude change characteristic value and the delay change characteristic value; When the electromagnetic anomaly coefficient of the motor rotor at a certain measuring point is greater than a preset threshold, the frequency domain information in the time interval sequence corresponding to the measuring point is analyzed to calculate the current time series interval; a current signal is constructed based on the current time series interval and the current value sequence corresponding to the measuring point; when the electromagnetic anomaly coefficient of the motor rotor at a certain measuring point is less than or equal to the preset threshold, the current value sequence at the measuring point is used as the current signal; The motor rotor is positioned according to the change of the current value in the current signal at all the measuring points.

2. A propulsion motor rotor position observation method according to claim 1, characterized in that: The method for obtaining the amplitude variation characteristic value comprises: Preset a rotor period, and segment each current value sequence based on the rotor period to obtain period data segments; In each current value sequence, the first cycle data segment is used as a reference data segment, and the remaining cycle data segments are used as comparison data segments; The difference between each current value in the reference data segment and the current value at the same position in each comparison data segment is used as an amplitude variation factor; The sum of all amplitude variation factors of the reference data segment and each comparison data segment is taken as the variation coefficient of the current; The normalized value of the sum of the current variation coefficients between the reference data segment and all the comparison data segments is used as the current amplitude variation characteristic value.

3. A propulsion motor rotor position observation method according to claim 2, characterized in that: The method for obtaining the delay variation characteristic value includes: Segmenting the time interval sequence corresponding to each current value sequence based on the rotor period to obtain time interval data segments; In each time interval data segment, the last value is taken as the reference value, all the remaining values ​​are taken as comparison values, the difference between the reference value and each comparison value is taken as the time difference factor, and the sum of all the time difference factors is taken as the time difference coefficient; The normalized sum of the time difference coefficients corresponding to all time interval data segments is used as the delay variation characteristic value of the time interval series.

4. A propulsion motor rotor position observation method according to claim 1, characterized in that: The method for obtaining the electromagnetic anomaly coefficient includes: Preset proportion coefficient; At each measuring point, the product of the proportion coefficient and the amplitude change characteristic value corresponding to the current value sequence is used as the first abnormal factor; The product of the value after negative correlation mapping of the proportion coefficient and the delay variation characteristic value of the time interval sequence corresponding to the current value sequence is used as the second abnormal factor; The normalized value of the sum of the first and second anomaly factors is used as the electromagnetic anomaly coefficient of the motor rotor at each measuring point.

5. A propulsion motor rotor position observation method according to claim 1, characterized in that: The method for obtaining the current time interval includes: Performing discrete Fourier transform on the time interval sequence to obtain a frequency spectrum; In the spectrum graph, the mean of the amplitudes of all frequencies is calculated as the amplitude mean, and the frequency whose amplitude is greater than or equal to the amplitude mean is taken as the target frequency; The corresponding period value is calculated according to each target frequency, and the average of all period values ​​is used as the current timing interval.

6. A propulsion motor rotor position observation method according to claim 1, characterized in that: The constructing of the current signal based on the current time interval and the current value sequence corresponding to the measuring point includes: In terms of time sequence, the current values ​​in the current value sequence corresponding to the measuring point are arranged according to the current time sequence interval, so as to obtain a current signal.

7. A propulsion motor rotor position observation method according to claim 1, characterized in that: The method for acquiring the time interval sequence comprises: In each of the current value sequences, the time interval between every two adjacent current values ​​is taken as a value in the time interval sequence.

8. A propulsion motor rotor position observation method according to claim 1, characterized in that: Positioning the motor rotor according to the change of the current value in the current signal at all the measuring points includes: Perform edge detection on each current signal to obtain the moments of the current rising edge and the current falling edge as edge moments; According to the position of each measuring point in the motor and the edge moment in the current signal at each measuring point, the position information of the motor rotor at each edge moment is determined.

9. A propulsion motor rotor position observation method according to claim 4, characterized in that: The value range of the preset proportion coefficient is (0.5, 1).

10. A propulsion motor rotor position observation system, characterized in that: It includes a processor and a memory, wherein the memory stores at least one instruction, at least one program, code set or instruction set, and when the at least one instruction, at least one program, code set or instruction set is loaded and executed by the processor, the steps of a propulsion motor rotor position observation method as described in any one of claims 1 to 9 are implemented.

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