A motor calibration method and device

Abstract

The application provides a motor calibration method, which comprises the following steps: obtaining a calibration point matrix, and then obtaining a direct-axis current search interval of a target working condition; when the direct-axis current search interval is not empty, searching for an optimal working current of the target working condition by using a preset search algorithm; when the direct-axis current search interval is empty, stopping searching for the optimal working current of the remaining working conditions under the target rotating speed, and taking the working conditions under other remaining rotating speeds as next target working conditions, so that the fast calibration of each working condition point is realized while the accuracy requirement is ensured, the calibration time is shortened, the maximum efficiency control is realized in the form of searching, and the motor external characteristic under the current rotating speed is autonomously determined in the case that the current search interval is empty, so that the self-adaptation is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of motor control and calibration, and particularly relates to a motor calibration method and device. BACKGROUND

[0002] With the current social and economic development, energy crisis and environmental problems are becoming more and more serious. New energy power mainly based on electric motor (also known as motor) is applied more and more in many aspects such as automobile, engineering machinery, ship, etc. In recent years, alternating current motor, especially permanent magnet synchronous motor, has been widely concerned and researched.

[0003] At present, vector control is the mainstream scheme of motor control, which has the advantages of smooth torque output, fast response, wide speed regulation range, and accurate control of motor torque. Before the motor is formally used, in order to achieve the best state of motor performance, the motor often needs to be calibrated. The conventional calibration method is to divide a grid in the motor external characteristic interval, and to calibrate the target current of each calibration point in turn, so that the output torque matches the target demand torque.

[0004] Although this method can achieve accurate output of torque, the calibration workload is large, the data is much, and it is difficult to calibrate all motors of the same batch in engineering. In vector control, whether it is a control method with zero direct axis component or a maximum torque per ampere (MTPA) control method, it is necessary to cooperate with field weakening control in the high speed range to improve the motor operating speed range and maximum output torque.

[0005] If the motor is calibrated in the conventional way, it is relatively time-consuming and laborious. Therefore, there is an urgent need in the industry to provide a fast and reliable calibration method. SUMMARY

[0006] The present application provides a motor calibration method. The method obtains a calibration point matrix through a calibration device, and then obtains a direct axis current search interval of a target working condition. When the direct axis current search interval is not empty, the optimal working current of the target working condition is searched through a preset search algorithm. When the direct axis current search interval is empty, the search of the optimal working current of the remaining working conditions under the target speed is stopped, and the working conditions under other remaining speeds are taken as the next target working condition. Thus, while ensuring the accuracy requirement, the fast calibration of each working condition point is realized, the calibration time is shortened, the maximum efficiency control is realized in the form of search, and in the case that the current search interval is empty, the motor external characteristic under the current speed is determined automatically, and the self-adaptation is realized.

[0007] In a first aspect, the present application provides a motor calibration method, which comprises:

[0008] The calibration point matrix includes a plurality of calibration points, and each calibration point corresponds to a working condition used to describe the speed and torque of the motor;

[0009] The direct-axis current search interval of the target working condition is obtained, the target working condition is a working condition corresponding to one of the calibration points, and the speed of the motor under the target working condition is a target speed;

[0010] When the direct-axis current search interval is not empty, the optimal working current of the target working condition is searched through a preset search algorithm, and when the direct-axis current search interval is empty, the optimal working current of the remaining working conditions under the target speed is stopped from being searched, the working conditions under the other remaining speeds are taken as next target working conditions, and the optimal working current includes the direct-axis current and the quadrature-axis current when the motor efficiency is optimal.

[0011] In some possible implementation manners, the preset search algorithm includes at least one of a golden section method or a dichotomy method.

[0012] In some possible implementation manners, the direct-axis current search interval of the target working condition is obtained, including:

[0013] When the target working condition corresponds to a first calibration point under the target speed, a current limit circle determined by the preset current threshold is taken as the search interval of the target working condition.

[0014] When the target working condition corresponds to a non-first calibration point under the target speed, a neighborhood of the optimal working current of a previous calibration point corresponding to the target speed is taken as the search interval of the target working condition.

[0015] In some possible implementation manners, the method further includes:

[0016] The direct-axis current search interval is corrected.

[0017] In some possible implementation manners, the direct-axis current search interval is corrected, including:

[0018] The direct-axis current search interval is corrected according to the voltage limit circle set and the current limit circle of the motor.

[0019] In some possible implementation manners, when the direct-axis current search interval is not empty, the optimal working current of the target working condition is searched through the preset search algorithm, including:

[0020] When the corrected direct-axis current search interval is not empty, iterative searching is performed on the corrected direct-axis current search interval as an initial search interval to obtain a new search interval, and the new search interval is a search interval compressed according to a preset ratio;

[0021] When the length of the search interval is not greater than a preset interval length, the iteration is stopped, and the optimal working current is obtained according to the search interval.

[0022] In some possible implementations, the method also includes:

[0023] By fitting the optimal operating current at each calibration point, a two-dimensional function of the optimal operating current with respect to torque and speed is obtained for the entire speed range.

[0024] Secondly, this application provides a motor calibration device, which includes:

[0025] The communication module is used to acquire the calibration point matrix, which includes multiple calibration points. Each calibration point corresponds to a working condition, which describes the motor's speed and torque.

[0026] The search interval determination module is used to obtain the direct-axis current search interval of the target working condition. The target working condition is the working condition corresponding to one of the multiple calibration points, and the motor speed under the target working condition is the target speed.

[0027] The search module is used to search for the optimal operating current of the target operating condition using a preset search algorithm when the direct-axis current search interval is not empty. When the direct-axis current search interval is empty, the search for the optimal operating current of the remaining operating conditions at the target speed is stopped, and the operating conditions at other remaining speeds are taken as the next target operating condition. The optimal operating current includes the direct-axis current and quadrature-axis current when the motor efficiency is optimal.

[0028] In some possible implementations, the preset search algorithm includes at least one of the golden section method or the bisection method.

[0029] In some possible implementations, the search interval determination module is specifically used for:

[0030] When the target operating condition corresponds to the first calibration point at the target speed, the current limit circle determined by the preset current threshold is used as the search interval for the target operating condition.

[0031] When the target operating condition corresponds to a non-first calibration point at the target speed, the neighborhood of the optimal operating current at the previous calibration point corresponding to the target speed is taken as the search interval for the target operating condition.

[0032] In some possible implementations, the device also includes:

[0033] The correction module is used to correct the direct-axis current search range.

[0034] In some possible implementations, the correction module is specifically used for:

[0035] The direct-axis current search range is corrected based on the set of voltage and current limit circles of the motor.

[0036] In some possible implementations, the search module is specifically used for:

[0037] When the corrected direct-axis current search interval is not empty, iterative search is performed with the corrected direct-axis current search interval as the initial search interval to obtain a new search interval. The new search interval is the search interval compressed according to the preset ratio.

[0038] When the length of the search interval is not greater than the preset interval length, the iteration stops, and the optimal operating current is obtained based on the search interval.

[0039] In some possible implementations, the device also includes:

[0040] The fitting module is used to fit the optimal operating current at each calibration point to obtain a two-dimensional function of the optimal operating current with respect to torque and speed over the entire speed range.

[0041] Thirdly, this application provides an apparatus including a processor and a memory. The processor and the memory communicate with each other. The processor executes instructions stored in the memory to cause the apparatus to perform a motor calibration method as described in the first aspect or any implementation thereof.

[0042] Fourthly, this application provides a computer-readable storage medium storing instructions that instruct a device to perform the motor calibration method described in the first aspect or any implementation thereof.

[0043] Fifthly, this application provides a computer program product containing instructions that, when run on a device, causes the device to perform the motor calibration method described in the first aspect or any implementation thereof.

[0044] Based on the implementation methods provided in the above aspects, this application can be further combined to provide more implementation methods.

[0045] As can be seen from the above technical solutions, the embodiments of this application have the following advantages:

[0046] This application provides a motor calibration method. A calibration point matrix is ​​obtained using calibration equipment, and then a direct-axis current search interval for the target operating condition is obtained. When the direct-axis current search interval is not empty, the optimal operating current for the target operating condition is searched using a preset search algorithm. When the direct-axis current search interval is empty, the search for the optimal operating current for the remaining operating conditions at the target speed is stopped, and the operating conditions at other remaining speeds are used as the next target operating condition. This method ensures accuracy requirements while achieving rapid calibration for each operating point, shortening calibration time. Furthermore, the search method achieves maximum efficiency control, and when the current search interval is empty, the motor's external characteristics at the current speed are autonomously determined, achieving self-adaptation. Attached Figure Description

[0047] To more clearly illustrate the technical methods of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 A schematic flowchart illustrating a motor calibration method provided in an embodiment of this application;

[0049] Figure 2 A schematic diagram illustrating the functional relationship between direct-axis current and speed-torque fitted using the least squares method, provided for embodiments of this application;

[0050] Figure 3 A schematic diagram of a process for obtaining a direct-axis current search range is provided for an embodiment of this application;

[0051] Figure 4 A flowchart illustrating a modified direct-axis current search range provided in an embodiment of this application;

[0052] Figure 5 This application provides a schematic diagram of drawing current circles and voltage circles at various speeds based on motor parameters.

[0053] Figure 6 A schematic diagram illustrating a modified direct-axis current search range provided in an embodiment of this application;

[0054] Figure 7 A flowchart illustrating a search for the optimal operating current range for a target operating condition point, provided in an embodiment of this application.

[0055] Figure 8 This is a schematic diagram of the structure of a motor calibration device provided in an embodiment of this application. Detailed Implementation

[0056] The solutions in the embodiments provided in this application will now be described with reference to the accompanying drawings.

[0057] The terms "first" and "second" used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0058] First, some technical terms involved in the embodiments of this application will be introduced.

[0059] Motor calibration refers to testing the relationship between the controller's output current and the motor's output torque on a test bench. Because different batches of motors have different inherent parameters, the current corresponding to torque and speed also varies. Without calibration, the motor cannot achieve its optimal operating state.

[0060] Typically, the calibration method for a motor involves dividing the motor's external characteristic range into a grid and sequentially calibrating the target current of the orthogonal axis at each calibration point to match the output torque with the target torque requirement.

[0061] However, while this method can achieve precise torque output, it requires a large calibration quantity and a large amount of data, making it difficult to calibrate all motors in the same batch in engineering practice. In vector control, whether it is a control method with zero direct-axis component or a control method based on maximum torque-to-current ratio (MTPA), field weakening control is required in the high-speed region, which is relatively time-consuming and labor-intensive.

[0062] At the same time, this conventional method does not take into account the impact of motor iron losses. Even with maximum torque-to-current ratio control, the calibrated motor still does not operate at its most efficient state. For the vehicle, its limited electrical energy storage is not fully utilized.

[0063] Therefore, this application provides a calibration method that can quickly achieve maximum efficiency control through a search algorithm. This method can be executed by a calibration device, which obtains a calibration point matrix and the direct-axis current search interval for the target operating condition. When the direct-axis current search interval is not empty, a preset search algorithm is used to search for the optimal operating current for the target operating condition. When the direct-axis current search interval is empty, the calibration device stops searching for the optimal operating current for the remaining operating conditions at the target speed, and uses the operating conditions at other remaining speeds as the next target operating condition. Thus, the optimal operating current that enables the motor to achieve maximum efficiency is obtained through a search. Furthermore, when the current search interval is empty, the motor's external characteristics at the current speed are autonomously determined, achieving self-adaptation.

[0064] The calibration device can be a computing device, such as a desktop computer, laptop computer, mobile phone, or server. The calibration device can also be a computing cluster formed by multiple computing devices.

[0065] To make the technical solution of this application clearer and easier to understand, the technical solution of this application will be described in detail below from the perspective of calibration equipment.

[0066] See Figure 1 A flowchart illustrating a motor calibration method provided in this application embodiment is shown. The method includes the following steps:

[0067] S102: The calibration equipment obtains the calibration point matrix.

[0068] The calibration point matrix includes multiple calibration points, each corresponding to a specific operating condition. These operating conditions describe the motor's speed and torque. Specifically, the calibration point matrix is ​​obtained by selecting calibration points sequentially from the origin to the maximum speed and maximum torque, based on the set speed and torque intervals.

[0069] To facilitate understanding, the calibration point matrix will be explained below with a specific example.

[0070] For example, the maximum speed of the motor to be calibrated is 10,000 revolutions per minute (rpm), and the maximum torque is 50 Newton-meters (Nm). The calibration points (metre, Nm) are selected with a speed interval of 2000 rpm and a torque interval of 10 Nm. With the same speed as the same row of the matrix and the same torque as the same column of the matrix, the first row of the final calibration point matrix is: (0,0), (0,10), (0,20), (0,30), (0,40), (0,50); the second row is: (2000,0), (2000,10), (2000,20), (2000,30), (2000,40), (2000,50); the third row is: (4000,0), (4000,10), (4000,20), (4000,30), (4000,40), (4000,50), and so on. They will not be listed one by one here.

[0071] S104: Calibrate the equipment to obtain the direct-axis current search range of the target working condition. The direct-axis current search range is a dynamically adjustable range. If the direct-axis current search range is empty, proceed to S106; otherwise, proceed to S108.

[0072] The target operating condition is the operating condition corresponding to one of the multiple calibration points mentioned above, and the motor speed under the target operating condition is the target speed. When searching for the target operating condition point sequentially, the speed is switched only after the operating condition points at the same speed have been calibrated, until all operating condition points within the external characteristics have been searched. That is, the speed values ​​are first taken sequentially from the minimum speed, then the torque values ​​are taken sequentially from the minimum torque. If the torque of the target operating condition point reaches the maximum torque, the speed is taken as a larger value in the sequence; if the speed of the target operating condition point reaches the maximum speed, the calibration point calibration stops.

[0073] Specifically, the direct-axis current search range is a dynamically adjusted range. When the target operating condition corresponds to the first calibration point at the target speed, the current limiting circle determined by the preset current threshold is used as the search range for the target operating condition. When the target operating condition corresponds to a non-first calibration point at the target speed, the neighborhood of the optimal operating current at the previous calibration point corresponding to the target speed is used as the search range for the target operating condition.

[0074] The size of the optimal operating current neighborhood at the previous calibration point is dynamically adjusted based on the current variation amplitude at the previous calibration point. Specifically, if the current variation amplitude is less than a first preset current threshold, the neighborhood is set to the first preset current threshold; if the current variation amplitude is greater than the first preset current threshold but less than a second preset current threshold, the neighborhood is set to the second preset current threshold; if the current variation amplitude is greater than the second preset current threshold, the neighborhood is set to a third preset current threshold. The preset current thresholds are determined based on the motor parameters and the torque interval at the operating point.

[0075] S106: When the direct-axis current search range is empty, the calibration equipment stops searching for the optimal operating current of the remaining operating conditions under the target speed, and takes the operating conditions under other remaining speeds as the next target operating conditions.

[0076] In this way, the motor's external characteristics at the current speed, i.e., the maximum torque, are determined without needing to preset parameters in advance, thus achieving self-adaptation.

[0077] Specifically, even if the calibration point torque does not reach the maximum torque, the search for the optimal operating current of the remaining operating conditions at the target speed is stopped, and the operating conditions at other remaining speeds are taken as the next target operating conditions.

[0078] S108: When the direct-axis current search range is not empty, the calibration device searches for the optimal operating current for the target operating condition using a preset search algorithm.

[0079] The preset search algorithm is a user-defined algorithm used to search for the optimal operating current within the direct-axis current search range. The optimal operating current includes the direct-axis current at which the motor efficiency is optimal. Furthermore, the optimal operating current also includes the quadrature-axis current at which the motor efficiency is optimal. After the calibration equipment uses the preset search algorithm to find the direct-axis current at which the motor efficiency is optimal, it determines the quadrature-axis current at which the motor efficiency is optimal.

[0080] The preset search algorithm may include at least one of the golden section method or the bisection method. Compressing the interval using the golden section method and the bisection method involves determining a new search interval and trial point based on the magnitude of the loss under the current. Specifically, the golden section method compresses the interval each time using the golden section point of the original interval (0.618), while the bisection method compresses the original interval each time using the halfway point of the original interval. This application does not impose any limitations on these methods.

[0081] In some possible implementations, the calibration device can also correct the direct-axis current search range. Specifically, the calibration device corrects the direct-axis current search range based on the motor's voltage limit circle set and current limit circle. The voltage limit circle set is determined by given motor parameters and a preset voltage threshold, while the current limit circle is determined by a preset current threshold.

[0082] When the corrected direct-axis current search interval is not empty, iterative search is performed using the corrected direct-axis current search interval as the initial search interval to obtain a new search interval. This new search interval is a search interval compressed according to a preset ratio. Iteration stops when the length of the search interval is not greater than the preset interval length, and the optimal operating current is determined based on the obtained search interval.

[0083] Specifically, the corrected direct-axis current search interval is set as the initial search interval. A trial-and-error search algorithm is used to iteratively search within the initial search interval to determine a new search interval. Each time the search is iterated, the search interval is compressed by a fixed factor L (usually L < 0.5). Throughout the search process, the optimal operating current always lies within the compressed current search interval. When If the search interval length is not greater than the preset interval length, stop the iteration and select the boundary point or internal test point of the search interval that meets the preset interval length condition as the optimal operating current of the target operating point.

[0084] In some possible implementations, iterative search can be achieved using the golden section method. Within the search interval, the test point is calculated, the quadrature-axis current at the test point that matches the torque of the target operating point is determined, the total system loss corresponding to the given orthogonal-axis current is calculated, and the magnitude of the total system loss is compared to determine a new search interval.

[0085] Specifically, the quadrature-axis current that matches the torque at the target operating point can be determined by calculating the initial value of the quadrature-axis current using the torque formula, taking values ​​iq1 and iq2 around the initial value respectively, measuring the corresponding output torques Te1 and Te2, and finally... Calculated.

[0086] S110: The calibration equipment fits the optimal operating current at each calibration point to obtain a two-dimensional function of the optimal operating current with respect to torque and speed across the entire speed range.

[0087] Specifically, based on the optimal operating current at each calibration point, a pre-defined fitting algorithm is used to perform polynomial fitting on the optimal operating current at each calibration point. The resulting two-dimensional function of the optimal operating current across the entire speed range with respect to torque and speed is:

[0088]

[0089] Among them, a k b represents the coefficients of each power of the speed term. k c is the coefficient of each power of the product of speed and torque. k These are the coefficients of each power of the torque term.

[0090] See Figure 2Taking least squares fitting as an example, the optimal direct-axis operating current corresponding to speed-torque is defined as z, speed as x, and torque as y. In the graph, different colors or different shades of gray represent different direct-axis current magnitudes; the darker the color, the smaller the direct-axis current. Specifically, the calibration equipment can be fitted using a quadratic polynomial according to the following formula:

[0091] z = a0 + a1x + a2y + a3x 2 +a4xy+a5y 2

[0092] Among them, a i (i = 0, ..., 5) are the coefficients of the fitted function.

[0093] Optionally, the formulas for calculating each coefficient can be:

[0094]

[0095] Similarly, the quadrature-axis current is fitted to obtain the functional relationship between the quadrature-axis current and the speed-torque.

[0096] S112: During motor control, based on the required speed and torque, the calibration equipment calculates the target current using this two-dimensional function and performs vector control.

[0097] In this application, by calibrating the motor as described above, a two-dimensional function of the optimal operating current with respect to torque and speed can be obtained across the entire speed range. Based on the required speed and torque, the calibration equipment uses this two-dimensional function to calculate the target current. By adjusting the current, the motor can achieve the required speed and torque, thereby controlling the motor output and realizing vector control.

[0098] It should be noted that the above embodiments are only an optional reference for the motor calibration method of this application, wherein S110 and S112 are optional steps, and in some embodiments, those steps may not be performed.

[0099] The above embodiment obtains a calibration point matrix through a calibration device, and then obtains the direct-axis current search interval for the target operating condition. When the direct-axis current search interval is not empty, the optimal operating current for the target operating condition is searched through a preset search algorithm. When the direct-axis current search interval is empty, the search for the optimal operating current for the remaining operating conditions under the target speed is stopped, and the operating conditions under other remaining speeds are taken as the next target operating condition.

[0100] Compared to conventional methods, this scheme, while ensuring torque accuracy requirements, rapidly calibrates each operating point through a search algorithm. While conventional methods might require 7-8 calibrations per point, this method may only need 3-4, achieving rapid calibration for each operating point and shortening the calibration time. The total system loss at each trial point serves as the basis for the search algorithm's compression, and the resulting calibration can be considered a vector control method different from id=0 and MTPA methods—maximum efficiency control. This method can achieve optimal efficiency, but its mathematical analytical solution is difficult to obtain. This scheme employs a search method to achieve maximum efficiency control. Furthermore, in this case, if the current search range is empty, the current speed calibration is stopped, thereby achieving adaptive determination of the external characteristics (i.e., the maximum torque of the motor at each speed).

[0101] The following provides another possible implementation of the process for obtaining the direct-axis current search range of the calibration device in this application.

[0102] Specifically, the process of calibrating the equipment to obtain the direct-axis current search range is described in [reference needed]. Figure 3 As shown.

[0103] S302: The calibration equipment determines whether the target operating condition is the first calibration point under the target speed. If the target operating condition is the first calibration point under the target speed, proceed to S304; otherwise, proceed to S306.

[0104] S304: The calibration equipment uses the current limit circle determined by the preset current threshold as the search range for the target operating point and proceeds to S318.

[0105] S306: The calibration device determines whether the current change amplitude is less than the first preset current threshold. If the current change amplitude is less than the first preset current threshold, proceed to S308; otherwise, proceed to S310.

[0106] S308: The calibration device sets the neighborhood to the first preset current threshold and proceeds to S316.

[0107] S310: The calibration device determines whether the current change amplitude is less than the second preset current threshold. If the current change amplitude is less than the first preset current threshold, proceed to S312; otherwise, proceed to S314.

[0108] S312: The calibration device sets the neighborhood to the second preset current threshold and proceeds to S316.

[0109] S314: The calibration device sets the neighborhood to the third preset current threshold and proceeds to S316.

[0110] S316: The calibration equipment uses the optimal operating current neighborhood of the previous calibration point at the target speed as the search interval for the target operating point, and then proceeds to S318.

[0111] S318: Calibrate the equipment to determine the direct-axis current search range for the target operating point.

[0112] The preset current threshold is determined based on the motor parameters and the torque interval at the operating point.

[0113] The above provides an embodiment for obtaining the direct-axis current search range using a calibration device by acquiring the current change amplitude and a preset current threshold. This allows for dynamic acquisition of the direct-axis current search range. It should be noted that the above embodiment is merely an optional reference for the motor calibration method of this application; other methods can also be used to obtain the direct-axis current search range for the target operating condition. This application is not limited to this. The following provides another possible implementation of the process for the calibration device to correct the direct-axis current search range in this application. In one possible embodiment, the process for the calibration device to correct the direct-axis current search range is described below. Figure 4 As shown.

[0114] S402: The calibration equipment obtains the set of current limit circles and voltage limit circles for the motor.

[0115] The current limiting circle is determined by a preset current threshold. 2 +iq 2 <imax 2 The voltage limiting circle set is determined by the given motor parameters and the preset voltage threshold Ud. 2 +Uq 2 <U_lim 2 The current circle and voltage sources at various speeds are drawn based on the specific motor parameters, referring to... Figure 5 As shown.

[0116] S404: The intersection of the feedback current circle of the calibration equipment and the voltage limit circle corresponding to the target operating point speed.

[0117] S406: The calibration equipment corrects the direct-axis current search range according to the first preset correction algorithm.

[0118] Specifically, if the left boundary point of the direct-axis current search interval is less than the minimum direct-axis current of the above intersection, the left boundary point is corrected to the smaller of the minimum direct-axis current of the intersection and the right boundary point; if the right boundary point is greater than the maximum direct-axis current of the intersection, the right boundary point is corrected to the larger of the maximum value and the left boundary point, thereby correcting the direct-axis current search interval.

[0119] S408: The calibration device obtains the quadrature axis current threshold corresponding to each direct axis current.

[0120] S410: The quadrature axis current at the left and right boundary points of the calibration equipment, corresponding to the torque at the target operating point.

[0121] S412: The calibration equipment determines whether the quadrature shaft current corresponding to the torque at the target operating point is greater than the quadrature shaft current threshold. If the quadrature shaft current corresponding to the torque at the target operating point is greater than the quadrature shaft current threshold, execute S414; otherwise, execute S416.

[0122] S414: The calibration equipment adjusts the direct-axis current search range according to the second preset correction algorithm, and then proceeds to S418.

[0123] Specifically, if the quadrature-axis current corresponding to the left boundary point of the direct-axis current search interval is greater than the aforementioned quadrature-axis current threshold, the left boundary of the direct-axis current search interval is adjusted to the right. If the quadrature-axis current corresponding to the right boundary point of the direct-axis current search interval is greater than the aforementioned quadrature-axis current threshold, the right boundary of the direct-axis current search interval is adjusted to the left. If the left boundary of the search interval is adjusted to the right boundary, then the direct-axis current search interval is empty. If the right boundary is adjusted to the left boundary, then the direct-axis current search interval is empty. When the direct-axis current search interval after the above correction is not empty, proceed to S416.

[0124] S416: Calibrate the corrected direct-axis current search range for the equipment output.

[0125] S418: Calibrate the quadrature shaft current corresponding to the torque at the target operating point calculated by the calibration equipment.

[0126] See Figure 6 This application provides an example of calibrating a device to correct the direct-axis current search range. At the target operating point of 8000 rpm and 30 Nm, the direct-axis current search range is set to [l0, r0]. The right boundary point is outside the intersection of the limiting circles and is corrected to r1 according to the first preset algorithm. The corrected search range is [l1, r1]. The cross-axis current corresponding to the left and right boundary points and the target torque exceeds the current threshold. The left and right boundaries are corrected to l2 and r2 according to the second preset algorithm. The corrected search range is [l2, r2].

[0127] The above-mentioned first and second preset correction algorithms correct the direct-axis current search range when the quadrature-axis current corresponding to the direct-axis current exceeds the current threshold, thus obtaining a more accurate direct-axis current search range. It should be noted that the above embodiments are only an optional reference for the motor calibration method of this application. In practical applications, other methods can also be used to correct the search range of the direct-axis current. This application is not limited to this.

[0128] The following provides another possible implementation of the process for calibrating the range of optimal operating current for the target operating point of the equipment in this application.

[0129] In one possible embodiment, the range of the optimal operating current for the calibration device to search for the target operating point is described in [reference]. Figure 7 As shown.

[0130] S702: The calibration equipment determines the corrected direct-axis current search interval as the initial search interval [a,b].

[0131] S704: The calibration equipment sets test points x1 and x2, x1 = a + 0.382(ba), x2 = b - 0.382(ba), and the system loss is a function of the direct-axis current, denoted as f(x1) and f(x2).

[0132] S706: The calibration device determines whether the length of the search interval is not greater than the preset interval length. If it is, proceed to S714; otherwise, proceed to S708.

[0133] S708: The calibration equipment determines whether the total loss at test point 1 is less than the total loss at test point 2. If so, proceed to S710; otherwise, proceed to S712.

[0134] S710: The calibration equipment determines a new search interval: a = a, b = x2, x2 = x1, proceeding to S704. That is, the left endpoint of the new search interval remains unchanged, and the right endpoint becomes the original trial point x2.

[0135] S712: The calibration equipment determines a new search interval: a = x1, b = b, x1 = x2, and proceeds to S704. That is, the left endpoint of the new search interval becomes the original trial point x1, while the right endpoint remains unchanged.

[0136] S714: The calibration device stops iterating and selects the boundary point or internal test point of the search interval that meets the preset interval length condition as the optimal operating current of the target operating point.

[0137] The above iterative search of the optimal operating current range for the target operating point was performed using the golden section method, resulting in a compressed new search range, which narrowed the range and improved accuracy.

[0138] The motor calibration method provided in this application is applicable to automatic or semi-automatic control calibration. Before calibration begins, various preset thresholds are pre-entered into the program. During calibration, the program automatically calculates, adjusts, and records the values ​​without human intervention. Alternatively, it can be manually controlled by calibration personnel, who can input the target operating points sequentially and intervene manually during the calibration process. The preset thresholds include: current threshold, voltage threshold, maximum given motor speed, maximum torque, given speed intervals, and torque intervals. The entire speed range of the motor is divided into speed sequences, and each speed is further divided into torque sequences, thus forming a calibration point matrix.

[0139] Corresponding to the above method embodiments, this application also provides a motor calibration device, see [link to relevant documentation]. Figure 8The device 800 includes: a communication module 802, a search interval determination module 804, and a search module 806.

[0140] The communication module 802 is used to acquire the calibration point matrix, which includes multiple calibration points. Each calibration point corresponds to a working condition, which describes the motor's speed and torque.

[0141] The search interval determination module 804 is used to obtain the direct-axis current search interval of the target working condition. The target working condition is the working condition corresponding to one of the multiple calibration points, and the motor speed under the target working condition is the target speed.

[0142] The search module 806 is used to search for the optimal operating current of the target operating condition through a preset search algorithm when the direct-axis current search interval is not empty. When the direct-axis current search interval is empty, the search for the optimal operating current of the remaining operating conditions under the target speed is stopped, and the operating conditions under other remaining speeds are taken as the next target operating condition. The optimal operating current includes the direct-axis current and quadrature-axis current when the motor efficiency is optimal.

[0143] In some possible implementations, the preset search algorithm includes at least one of the golden section method or the bisection method.

[0144] In some possible implementations, the search interval determination module 804 is specifically used for:

[0145] When the target operating condition corresponds to the first calibration point at the target speed, the current limit circle determined by the preset current threshold is used as the search interval for the target operating condition.

[0146] When the target operating condition corresponds to a non-first calibration point at the target speed, the neighborhood of the optimal operating current at the previous calibration point corresponding to the target speed is taken as the search interval for the target operating condition.

[0147] In some possible implementations, the device 800 also includes:

[0148] The correction module is used to correct the direct-axis current search range.

[0149] In some possible implementations, the correction module is specifically used for:

[0150] The direct-axis current search range is corrected based on the set of voltage and current limit circles of the motor.

[0151] In some possible implementations, the search module 806 is specifically used for:

[0152] When the corrected direct-axis current search interval is not empty, iterative search is performed with the corrected direct-axis current search interval as the initial search interval to obtain a new search interval. The new search interval is the search interval compressed according to the preset ratio.

[0153] When the length of the search interval is not greater than the preset interval length, the iteration stops, and the optimal operating current is obtained based on the search interval.

[0154] In some possible implementations, the device 800 also includes:

[0155] The fitting module is used to fit the optimal operating current at each calibration point to obtain a two-dimensional function of the optimal operating current with respect to torque and speed over the entire speed range.

[0156] According to the embodiments of this application, the motor calibration device 800 can correspondingly execute the method described in the embodiments of this application, and the above and other operations and / or functions of each module of the motor calibration device 800 are respectively for implementing Figure 1 For the sake of brevity, the corresponding processes of each method in the code will not be elaborated here.

[0157] This application provides an apparatus for implementing an access control method. The apparatus includes a processor and a memory. The processor and the memory communicate with each other. The processor executes instructions stored in the memory to cause the apparatus to perform a motor calibration method.

[0158] This application provides a computer-readable storage medium storing instructions that, when executed on a device, cause the device to perform the aforementioned motor calibration method.

[0159] This application provides a computer program product containing instructions that, when run on a device, causes the device to perform the above-described motor calibration method.

[0160] It should also be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. In addition, in the device embodiment drawings provided in this application, the connection relationship between modules indicates that they have a communication connection, which can be implemented as one or more communication buses or signal lines.

[0161] Through the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware, or it can be implemented by special-purpose hardware including application-specific integrated circuits, special-purpose CPUs, special-purpose memory, special-purpose components, etc. Generally, any function performed by a computer program can be easily implemented by corresponding hardware, and the specific hardware structure used to implement the same function can also be diverse, such as analog circuits, digital circuits, or special-purpose circuits. However, for this application, software program implementation is more often the preferred implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium, such as a computer floppy disk, USB flash drive, mobile hard disk, ROM, RAM, magnetic disk, or optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, training equipment, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0162] In the above embodiments, the implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, in the form of a computer program product.

[0163] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, training device, or data center to another website, computer, training device, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a training device or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

Claims

1. A method for calibrating a motor, characterized in that, The method includes: Obtain a calibration point matrix, which includes multiple calibration points, each corresponding to a working condition, which is used to describe the speed and torque of the motor; Obtain the direct-axis current search range for the target operating condition, wherein the target operating condition is the operating condition corresponding to one of the multiple calibration points, and the motor speed under the target operating condition is the target speed; When the direct-axis current search interval is not empty, the optimal operating current of the target operating condition is searched by a preset search algorithm. When the direct-axis current search interval is empty, the search for the optimal operating current of the remaining operating conditions under the target speed is stopped, and the operating conditions under other remaining speeds are taken as the next target operating condition. The optimal operating current includes the direct-axis current and quadrature-axis current when the motor efficiency is optimal. The direct-axis current search range is corrected.

2. The method according to claim 1, characterized in that, The preset search algorithm includes at least one of the golden section method or the bisection method.

3. The method according to claim 1, characterized in that, The search range for obtaining the direct-axis current under the target operating condition includes: When the target operating condition corresponds to the first calibration point at the target speed, the current limiting circle determined by the preset current threshold is used as the search interval for the target operating condition. When the target operating condition corresponds to a non-first calibration point at the target speed, the neighborhood of the optimal operating current at the previous calibration point corresponding to the target speed is taken as the search interval for the target operating condition.

4. The method according to claim 1, characterized in that, The correction of the direct-axis current search range includes: The direct-axis current search range is corrected based on the set of voltage limit circles and the set of current limit circles of the motor.

5. The method according to claim 1, characterized in that, When the direct-axis current search interval is not empty, the optimal operating current for the target operating condition is searched using a preset search algorithm, including: When the corrected direct-axis current search interval is not empty, the corrected direct-axis current search interval is used as the initial search interval for iterative search to obtain a new search interval, which is the search interval compressed according to a preset ratio. When the length of the search interval is not greater than the preset interval length, the iteration stops, and the optimal operating current is obtained based on the search interval.

6. The method according to any one of claims 1 to 5, characterized in that, The method further includes: By fitting the optimal operating current at each calibration point, a two-dimensional function of the optimal operating current with respect to torque and speed is obtained for the entire speed range.

7. A motor calibration device, characterized in that, The device includes: A communication module is used to acquire a calibration point matrix, which includes multiple calibration points, each calibration point corresponding to a working condition, and the working condition is used to describe the speed and torque of the motor. The search interval determination module is used to obtain the direct-axis current search interval of the target working condition. The target working condition is the working condition corresponding to one of the multiple calibration points, and the speed of the motor under the target working condition is the target speed. The search module is used to search for the optimal operating current of the target operating condition through a preset search algorithm when the direct-axis current search interval is not empty, and to stop searching for the optimal operating current of the remaining operating conditions under the target speed when the direct-axis current search interval is empty, and to take the operating conditions under other remaining speeds as the next target operating condition. The optimal operating current includes the direct-axis current and quadrature-axis current when the motor efficiency is optimal. The correction module is used to correct the direct-axis current search range.

8. A device, characterized in that, The device includes a processor and a memory; The processor is configured to execute instructions stored in the memory to cause the device to perform the method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, Includes instructions that instruct the device to perform the method as described in any one of claims 1 to 6.

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