A method and device for determining the external characteristic parameters of a drive motor based on tangent fitting

Abstract

The present application discloses a method and device for determining external characteristic parameters of a drive motor based on tangent fitting. The method includes obtaining interface parameters of the drive motor, and obtaining an external characteristic calculation curve of the drive motor according to the interface parameters; obtaining a tangent equation according to the external characteristic calculation curve; obtaining an external characteristic fitting curve of the drive motor according to the external characteristic calculation curve and the tangent equation; and determining the external characteristic parameters of the drive motor according to the external characteristic fitting curve. The present invention can automatically generate an external characteristic fitting curve of the drive motor only through the interface parameters of the drive motor, reducing the workload of developers, reducing the amount of calculation, improving the fitting accuracy, and also saving the internal storage space of the controller. In addition, since the motor torque fitted by the fitting curve is less than or equal to the actual torque, the service life of the drive motor can be extended and the durability of the drive motor can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle drive motors, and particularly to a method, device, electronic device and computer-readable storage medium for determining the external characteristic parameters of a drive motor based on tangent fitting. Background Technique

[0002] Under the dual pressures of environmental pollution and energy shortage, the development of electric vehicles is becoming increasingly rapid. The drive motor is an important part of an electric vehicle, mainly used to achieve the conversion of mechanical energy and electrical energy. The output torque of the drive motor is an important parameter for the control of the electric vehicle drive motor and is a technical guarantee for the safe and reliable operation of the whole vehicle. In the control of the drive motor of an electric vehicle, the opening of the accelerator pedal is multiplied by the external characteristic parameters of the drive motor to obtain the output torque currently desired by the driver. Therefore, in the control process of the electric vehicle drive motor, it is necessary to accurately obtain the external characteristic output parameters of the drive motor.

[0003] In the prior art, the external characteristic parameters of the drive motor of an electric vehicle are generally obtained by looking up a two-dimensional table of the external characteristic parameters of the drive motor. However, this method requires developers to set multiple horizontal and vertical speed-torque coordinate points in the control program of the drive motor. These coordinate points need to be calculated multiple times during development. Due to the accumulation of calculation errors and the risk of operation errors, the finally obtained external characteristic parameters of the drive motor are not accurate. Secondly, since the external characteristic parameters of the drive motors of different vehicle platforms are different, it is often necessary to recalculate again, increasing the workload of developers. In addition, storing the coordinate points of the two-dimensional table of the external characteristic parameters of the drive motor requires a large amount of memory space, increasing the actual application cost and affecting the operation efficiency. Finally, since the processing between each coordinate point is carried out by linear interpolation, the calculated torque of the drive motor is greater than the actual torque of the drive motor, and the excessive output torque will affect the service life of the drive motor.

[0004] Therefore, it is urgent to propose a method for determining the external characteristic parameters of the drive motor of an electric vehicle to reduce the workload of developers, improve the accuracy of fitting the external characteristic parameters of the drive motor, and save the internal storage space of the controller. Summary of the Invention

[0005] In view of this, it is necessary to provide a method, device, electronic device and computer-readable storage medium for determining the external characteristics of an electric vehicle drive motor based on tangent fitting to solve the problems of large workload, large calculation error and large occupied space existing in the determination of the existing external characteristic parameters of the drive motor.

[0006] To solve the above problems, the present invention provides a method for determining the external characteristic parameters of a drive motor based on tangent fitting, including:

[0007] Obtain the interface parameters of the drive motor, and obtain the external characteristic calculation curve of the drive motor according to the interface parameters;

[0008] Obtain the tangent equation according to the external characteristic calculation curve;

[0009] Obtain the external characteristic fitting curve of the drive motor according to the external characteristic calculation curve and the tangent equation;

[0010] Determine the external characteristic parameters of the drive motor according to the external characteristic fitting curve.

[0011] Further, obtaining the interface parameters of the drive motor and obtaining the external characteristic calculation curve of the drive motor according to the interface parameters includes:

[0012] Obtain the rated power, rated torque, rated speed and maximum speed of the drive motor;

[0013] Obtain the external characteristic calculation curve of the drive motor according to the rated power, rated torque, rated speed and maximum speed; the abscissa of the external characteristic calculation curve is the speed of the drive motor, and the ordinate is the torque of the drive motor.

[0014] Further, obtaining the tangent equation according to the external characteristic calculation curve includes:

[0015] Divide the external characteristic curve into several curve segments according to the rated speed and maximum speed of the drive motor;

[0016] Taking the endpoints of the curve segment as the tangent points, obtain the tangent equation.

[0017] Further, obtaining the external characteristic fitting curve of the drive motor according to the external characteristic calculation curve and the tangent equation includes:

[0018] Taking the first endpoint of the curve segment as the tangent point, obtain the first tangent equation; taking the second endpoint of the curve segment as the tangent point, obtain the second tangent equation;

[0019] Calculate the intersection coordinates of the first tangent equation and the second tangent equation;

[0020] Obtain the external characteristic fitting curve of the drive motor according to the intersection coordinates, the external characteristic calculation curve and the tangent equation.

[0021] Further, obtaining the external characteristic fitting curve of the drive motor according to the intersection coordinates, the external characteristic calculation curve and the tangent equation includes:

[0022] According to the speed value of the drive motor corresponding to the intersection coordinates, determine the calculation coordinates corresponding to the speed value on the external characteristic calculation curve;

[0023] Determine whether the error value between the intersection coordinates and the calculated coordinates is within a preset error range;

[0024] When the error value is within the preset error range, determine the intersection coordinates as the fitting coordinates;

[0025] Obtain the external characteristic fitting curve of the drive motor according to the fitting coordinates.

[0026] Further, when the error value is not within the preset error range, re-segment the external characteristic calculation curve and update the intersection coordinates;

[0027] Calculate the error update value between the updated intersection coordinates and the calculated coordinates.

[0028] Further, determine the external characteristic parameters of the drive motor according to the external characteristic fitting curve, including:

[0029] Obtain the rotational speed measurement value of the drive motor, and determine the torque value of the drive motor at the rotational speed measurement value according to the rotational speed measurement value and the external characteristic fitting curve.

[0030] The present invention also provides a device for determining the external characteristic parameters of a drive motor based on tangent fitting, including:

[0031] A calculation curve generation module, configured to obtain the interface parameters of the drive motor and obtain the external characteristic calculation curve of the drive motor according to the interface parameters;

[0032] A tangent equation generation module, configured to obtain a tangent equation according to the external characteristic calculation curve;

[0033] A fitting curve generation module, configured to obtain the external characteristic fitting curve of the drive motor according to the external characteristic calculation curve and the tangent equation;

[0034] An external characteristic parameter determination module, configured to determine the external characteristic parameters of the drive motor according to the external characteristic fitting curve.

[0035] The present invention also provides an electronic device, including a processor and a memory, where a computer program is stored on the memory, and when the computer program is executed by the processor, the method for determining the external characteristic parameters of a drive motor based on tangent fitting as described in any of the above technical solutions is implemented.

[0036] The present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the method for determining the external characteristic parameters of a drive motor based on tangent fitting as described in any of the above technical solutions is implemented.

[0037] Compared with the prior art, the beneficial effects of the present invention include: First, obtaining the interface parameters of the drive motor, and obtaining the external characteristic calculation curve of the drive motor according to the interface parameters; Second, obtaining the tangent equation according to the external characteristic calculation curve; Third, obtaining the external characteristic fitting curve of the drive motor according to the external characteristic calculation curve and the tangent equation; Finally, determining the external characteristic parameters of the drive motor according to the external characteristic fitting curve. The present invention can automatically generate the external characteristic fitting curve of the drive motor only through the interface parameters of the drive motor, reducing the workload of developers, reducing the amount of calculation, avoiding possible errors and mistakes in calculation, improving the fitting accuracy, and also saving the internal storage space of the controller; In addition, since the motor torque fitted by the fitting curve is less than or equal to the actual torque, the service life of the drive motor can be extended and the durability of the drive motor can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 FIG. is a schematic flowchart of an embodiment of a method for determining the external characteristic parameters of a drive motor based on tangent fitting provided by the present invention;

[0039] Figure 2 FIG. is a schematic algorithm flowchart of an embodiment of a method for determining the external characteristics of an electric vehicle drive motor based on tangent fitting provided by the present invention;

[0040] Figure 3 FIG. is a schematic diagram of an embodiment of the external characteristic fitting curve of a drive motor provided by the present invention;

[0041] Figure 4 FIG. is a schematic structural diagram of an embodiment of a device for determining the external characteristic parameters of a drive motor based on tangent fitting provided by the present invention;

[0042] Figure 5 FIG. is a structural block diagram of an embodiment of an electronic device provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] The following specifically describes the preferred embodiments of the present invention in conjunction with the drawings, wherein the drawings form a part of this application and are used together with the embodiments of the present invention to explain the principles of the present invention, and are not used to limit the scope of the present invention.

[0044] The present invention provides a method, device, electronic device and computer-readable storage medium for determining the external characteristic parameters of a drive motor based on tangent fitting, which are introduced in detail below.

[0045] An embodiment of the present invention provides a method for determining the external characteristic parameters of a drive motor based on tangent fitting, and its flowchart is as Figure 1 shown, including:

[0046] Step S101: Obtain the interface parameters of the drive motor, and obtain the external characteristic calculation curve of the drive motor according to the interface parameters;

[0047] Step S102: Obtain the tangent equation according to the external characteristic calculation curve;

[0048] Step S103: Obtain the external characteristic fitting curve of the drive motor according to the external characteristic calculation curve and the tangent equation;

[0049] Step S104: Determine the external characteristic parameters of the drive motor according to the external characteristic fitting curve.

[0050] For the method for determining the external characteristic parameters of a drive motor based on tangent fitting provided in this embodiment, first, obtain the interface parameters of the drive motor, and obtain the external characteristic calculation curve of the drive motor according to the interface parameters; second, obtain the tangent equation according to the external characteristic calculation curve; third, obtain the external characteristic fitting curve of the drive motor according to the external characteristic calculation curve and the tangent equation; finally, determine the external characteristic parameters of the drive motor according to the external characteristic fitting curve. The present invention can automatically generate the external characteristic fitting curve of the drive motor only through the interface parameters of the drive motor, reducing the workload of developers, reducing the amount of calculation, avoiding possible errors and mistakes in calculation, improving the fitting accuracy, and at the same time saving the internal storage space of the controller; in addition, since the motor torque fitted by the fitting curve is less than or equal to the actual torque, the service life of the drive motor can be extended and the durability of the drive motor can be improved.

[0051] As a preferred embodiment, in step S101, obtaining the interface parameters of the drive motor and obtaining the external characteristic calculation curve of the drive motor according to the interface parameters includes:

[0052] Obtain the rated power, rated torque, rated speed and maximum speed of the drive motor;

[0053] According to the rated power, rated torque, rated speed and maximum speed, obtain the external characteristic calculation curve of the drive motor; the abscissa of the external characteristic calculation curve is the speed of the drive motor, and the ordinate is the torque of the drive motor.

[0054] As a preferred embodiment, in step S102, obtaining the tangent equation according to the external characteristic calculation curve includes:

[0055] According to the rated speed and maximum speed of the drive motor, divide the external characteristic calculation curve into several curve segments;

[0056] Taking the endpoints of the curve segment as the tangent points, obtain the tangent equation.

[0057] As a preferred embodiment, in step S103, calculating the external characteristic fitting curve of the drive motor according to the external characteristic calculation curve and the tangent equation includes:

[0058] Taking the first endpoint of the curve segment as the tangent point to obtain a first tangent equation; taking the second endpoint of the curve segment as the tangent point to obtain a second tangent equation;

[0059] Calculating the intersection coordinates of the first tangent equation and the second tangent equation;

[0060] Obtaining the external characteristic fitting curve of the drive motor according to the intersection coordinates, the external characteristic calculation curve and the tangent equation.

[0061] As a preferred embodiment, obtaining the external characteristic fitting curve of the drive motor according to the intersection coordinates, the external characteristic calculation curve and the tangent equation includes:

[0062] Determining the calculation coordinates corresponding to the rotational speed value on the external characteristic calculation curve according to the rotational speed value of the drive motor corresponding to the intersection coordinates;

[0063] Judging whether the error value between the intersection coordinates and the calculation coordinates is within a preset error range;

[0064] When the error value is within the preset error range, determining the intersection coordinates as the fitting coordinates;

[0065] Obtaining the external characteristic fitting curve of the drive motor according to the fitting coordinates.

[0066] As a preferred embodiment, when the error value is not within the preset error range, re-segmenting the external characteristic calculation curve and updating the intersection coordinates;

[0067] Calculating the updated error value between the updated intersection coordinates and the calculation coordinates.

[0068] As a preferred embodiment, in step S104, determining the external characteristic parameters of the drive motor according to the external characteristic fitting curve includes:

[0069] Obtaining the rotational speed measurement value of the drive motor, and determining the torque value of the drive motor at the rotational speed measurement value according to the rotational speed measurement value and the external characteristic fitting curve.

[0070] The following combines Figure 2 , and uses a specific embodiment to illustrate the above solution in detail. Figure 2 is the schematic diagram of the algorithm flow of this embodiment.

[0071] Step S201: Obtain the drive motor interface parameters, including: rated power P e , rated torque T e , rated speed w e , maximum speed w max ;

[0072] According to the motor torque equation, it can be obtained that:

[0073] where N represents the torque constant, N = 9550.

[0074] Step S202: Draw the external characteristic calculation curve of the drive motor according to Equation (1), and divide the rated speed w e to the maximum speed w max into n segments, where n is a positive integer; then the speed length of each segment Δw represents the speed length; each speed length corresponds to a segment of the external characteristic calculation curve segment.

[0075] Step S203: Each segment of the external characteristic calculation curve corresponding to the speed length has two end points at the head and the tail. Assume that the coordinates of the head end point of the i-th curve segment are (w′ i , T′ i ), then:

[0076]

[0077] where w′ i —— the speed corresponding to the head end point of the i-th curve segment, T′ i —— the torque corresponding to the head end point of the i-th curve segment; i —— the serial number of the speed length, and the value range is i ∈ [1, n].

[0078] Step S204: Take the head end point of the i-th curve segment as the i-th tangent point, and find the slope of the i-th tangent point on the external characteristic calculation curve:

[0079]

[0080] where K i represents the tangent slope of the i-th tangent point.

[0081] According to Equation (2) and Equation (3), it can be obtained that:

[0082] T′ i = -K i * w′ i = -K i * (w e + (i - 1) * Δw) (4)

[0083] Using the tangent slope at the \(i\)-th tangent point and the coordinates of the \(i\)-th tangent point, the tangent equation at the \(i\)-th tangent point is obtained:

[0084] T = K i *(w - w′ i ) + T′ i (5)

[0085] Substituting Equation (4) into Equation (5), we can obtain:

[0086] T = K i *(w - w′ i ) - K i *w′ i = K i *(w - 2w′ i ) (6)

[0087] Simplifying Equation (6), we get:

[0088] T = K i *(w - 2(w e + (i - 1)*Δw)) (7)

[0089] Similarly, the tail coordinates of the \(i\)-th curve segment, that is, the tangent equation at the \((i + 1)\)-th tangent point, can be obtained:

[0090] T = K i+1 *(w - 2(w e + i*Δw)) (8)

[0091] where K i+1 represents the tangent slope at the \((i + 1)\)-th tangent point.

[0092] Step S204: Calculate the tangent intersection coordinates \((w i , T i ) of the tangent equation at the \(i\)-th tangent point and the tangent equation at the \((i + 1)\)-th tangent point, and we can obtain:

[0093]

[0094] where: w i —— the rotational speed of the tangent intersection of the tangent equation at the \(i\)-th tangent point and the tangent equation at the \((i + 1)\)-th tangent point; T i —— the torque of the tangent intersection of the tangent equation at the \(i\)-th tangent point and the tangent equation at the \((i + 1)\)-th tangent point.

[0095] Simplifying Equation (9) according to Equation (3), the rotational speed and torque of the intersection coordinates are expressed as:

[0096]

[0097] Step S205: Calculate the calculated coordinates of the rotational speed corresponding to the intersection coordinates on the external characteristic calculation curve, and judge the error value between the intersection coordinates and the calculated coordinates:

[0098]

[0099] Where, E(T) —— the maximum absolute error; δ(T) —— the maximum relative error.

[0100] Step S206: Judge whether E(T) and δ(T) satisfy E(T) ≤ ΔT and δ(T) ≤ δ,

[0101] Where, ΔT —— the maximum absolute error threshold, which can be changed by the calibration method, preferably 50 Nm; δ —— the maximum relative error threshold, δ ∈ (0, 1), which can be changed by the calibration method, preferably 5%;

[0102] If E(T) ≤ ΔT and δ(T) ≤ δ are satisfied, go to step S2208; if not, go to step S207.

[0103] Step S207: Re-segment the rotational speed, let n = n + 1, and update the rotational speed length And return to step S203.

[0104] Step S208: Determine the intersection coordinates as the fitting coordinates, and according to the fitting coordinates, obtain the relationship between the rotational speed and torque of the drive motor:

[0105] When w < w e the external characteristic fitting equation of the motor:

[0106] T = T e

[0107] When i takes the value of 1, w e ≤ w < w1, the external characteristic fitting equation of the motor:

[0108] T = K1 * (w - 2(w e + Δw))

[0109] When i takes values from 2 to n, w i-1 ≤ w < w i , the external characteristic fitting equation of the motor:

[0110] T = K i * (w - 2(w e + (i - 1) * Δw))

[0111] When w n ≤ w < w max , the external characteristic fitting equation of the motor:

[0112] T = K n+1*(w - 2(w e + n * Δw))

[0113] When w max ≤ w < w max + Δw, the fitting equation of the external characteristic of the motor is:

[0114]

[0115] When w max + Δw ≤ w, the fitting equation of the external characteristic of the motor is:

[0116] T = 0

[0117] Where: T - the fitting torque of the external characteristic of the motor;

[0118] According to the above fitting equation of the external characteristic, the fitting curve of the external characteristic of the drive motor is:

[0119]

[0120] Step S209: Determine the external characteristic parameters of the drive motor according to the fitting curve.

[0121] As Figure 3 shown, Figure 3 is a schematic diagram of the fitting curve of the external characteristic of the drive motor. The solid line in the figure is the fitting curve of the external characteristic of the motor in this embodiment, and the dotted line is the actual external characteristic curve of the motor.

[0122] It can be seen from the above analysis that developers only need to input the rated power P e , the rated torque T e , the rated speed w e , the highest speed and the rated speed w e to the highest speed w max divided into the number of segments n. With these five parameters, the external characteristic curve of the motor can be automatically fitted, greatly reducing the workload of developers. There is no need to perform multiple calculations like the method of looking up a two-dimensional table, avoiding calculation errors and mistakes, and avoiding storing multiple coordinate points, saving the internal storage space of the controller. In addition, the absolute error and relative error of the torque fitted by the method of this embodiment can be changed through calibration adjustment, improving the fitting accuracy of the external characteristic parameters of the drive motor. The torque of the motor fitted by the method of this embodiment is less than or equal to the actual external characteristic torque of the motor, which can improve the durability of the drive motor and extend its service life.

[0123] This embodiment also provides a device for determining the external characteristic of a drive motor based on tangent fitting. The structural block diagram is as Figure 4 shown. The device 400 for determining the external characteristic of a drive motor based on tangent fitting includes:

[0124] The calculation curve generation module 401 is configured to obtain the interface parameters of the drive motor, and obtain the external characteristic calculation curve of the drive motor according to the interface parameters;

[0125] The tangent equation generation module 402 is configured to obtain the tangent equation according to the external characteristic calculation curve;

[0126] The fitting curve generation module 403 is configured to obtain the external characteristic fitting curve of the drive motor according to the external characteristic calculation curve and the tangent equation;

[0127] The external characteristic parameter determination module 404 is configured to determine the external characteristic parameters of the drive motor according to the external characteristic fitting curve.

[0128] As Figure 5 shown, for the above method for determining the external characteristics of a drive motor based on tangent fitting, the present invention also correspondingly provides an electronic device 500, which may be a computing device such as a mobile terminal, a desktop computer, a notebook, a palm computer, and a server. The electronic device includes a processor 501, a memory 502, and a display 503.

[0129] The memory 502 may be an internal storage unit of the computer device in some embodiments, such as the hard disk or memory of the computer device. The memory 502 may also be an external storage device of the computer device in other embodiments, such as a plug-in hard disk equipped on the computer device, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, etc. Further, the memory 502 may also include both the internal storage unit and the external storage device of the computer device. The memory 502 is used to store application software installed in the computer device and various types of data, such as program codes installed in the computer device. The memory 502 may also be used to temporarily store data that has been output or will be output. In one embodiment, a program 504 for a method for determining the external characteristics of a drive motor based on tangent fitting is stored on the memory 502, and the program 504 for a method for determining the external characteristics of a drive motor based on tangent fitting can be executed by the processor 501, so as to implement the method for determining the external characteristics of a drive motor based on tangent fitting in various embodiments of the present invention.

[0130] The processor 501 may be a central processing unit (CPU), a microprocessor, or other data processing chips in some embodiments, and is used to run the program codes stored in the memory 502 or process data, such as executing a program for a method for determining the external characteristics of a drive motor based on tangent fitting.

[0131] In some embodiments, the display 503 may be an LED display, a liquid crystal display, a touch liquid crystal display, an OLED (Organic Light-Emitting Diode) touch device, etc. The display 503 is used to display information on the computer device and to display a visual user interface. The components 501 - 503 of the computer device communicate with each other via a system bus.

[0132] This embodiment also provides a computer-readable storage medium, on which a program for a method of determining the external characteristics of a drive motor based on tangent fitting is stored. When the processor executes the program, it implements a method of determining the external characteristics of a drive motor based on tangent fitting as described above.

[0133] According to the computer-readable storage medium and computing device provided in the above embodiments of the present invention, it can be implemented with reference to the content specifically described in implementing a method of determining the external characteristics of a drive motor based on tangent fitting as described above, and has beneficial effects similar to those of a method of determining the external characteristics of a drive motor based on tangent fitting as described above, which will not be elaborated here.

[0134] A method, device, electronic device, and computer-readable storage medium for determining the external characteristics of a drive motor based on tangent fitting disclosed by the present invention. First, obtain the interface parameters of the drive motor, and obtain the external characteristic calculation curve of the drive motor according to the interface parameters; secondly, obtain the tangent equation according to the external characteristic calculation curve; thirdly, obtain the external characteristic fitting curve of the drive motor according to the external characteristic calculation curve and the tangent equation; finally, determine the external characteristic parameters of the drive motor according to the external characteristic fitting curve.

[0135] The present invention can automatically generate the external characteristic fitting curve of the drive motor only through the interface parameters of the drive motor, reducing the workload of developers, reducing the amount of calculation, avoiding possible errors and mistakes in calculation, improving the fitting accuracy, and also saving the internal storage space of the controller; in addition, since the motor torque fitted by the fitting curve is less than or equal to the actual torque, the service life of the drive motor can be extended and the durability of the drive motor can be improved.

[0136] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for determining the external characteristic parameters of a drive motor based on tangent fitting, characterized in that, Including: Obtain the interface parameters of the drive motor, and obtain the external characteristic calculation curve of the drive motor according to the interface parameters; Obtain the tangent equation according to the external characteristic calculation curve; According to the external characteristic calculation curve and the tangent equation, obtain the external characteristic fitting curve of the drive motor, and the formula of the external characteristic fitting curve of the drive motor is: ， Wherein, is the rated power, is the rated torque, is the rated speed, is the speed of the drive motor, is the maximum speed. The rated speed to the maximum speed is divided into segments, is a positive integer, and the speed length of each segment , is the serial number of the speed length, and the value range is ∈[1, , represents the tangent slope of the th tangent point; Determine the external characteristic parameters of the drive motor according to the external characteristic fitting curve.

2. The method for determining the external characteristic parameters of a drive motor based on tangent fitting according to claim 1, wherein Obtain the interface parameters of the drive motor, and obtain the external characteristic calculation curve of the drive motor according to the interface parameters, including: Obtain the rated power, rated torque, rated speed and maximum speed of the drive motor; According to the rated power, rated torque, rated speed and maximum speed, obtain the external characteristic calculation curve of the drive motor; the abscissa of the external characteristic calculation curve is the speed of the drive motor, and the ordinate is the torque of the drive motor.

3. The method for determining the external characteristic parameters of a drive motor based on tangent fitting according to claim 2, wherein Obtain the tangent equation according to the external characteristic calculation curve, including: According to the rated speed and maximum speed of the drive motor, divide the external characteristic calculation curve into several curve segments; Taking the endpoints of the curve segment as the tangent points, obtain the tangent equation.

4. The method for determining the external characteristic parameters of a drive motor based on tangent fitting according to claim 3, wherein According to the external characteristic calculation curve and the tangent equation, obtain the external characteristic fitting curve of the drive motor, including: Taking the first endpoint of the curve segment as the tangent point, obtain the first tangent equation; taking the second endpoint of the curve segment as the tangent point, obtain the second tangent equation; Calculate the intersection coordinates of the first tangent equation and the second tangent equation; According to the intersection coordinates, the external characteristic calculation curve and the tangent equation, obtain the external characteristic fitting curve of the drive motor.

5. The method for determining the external characteristic parameters of a drive motor based on tangent fitting according to claim 4, wherein According to the intersection coordinates, the external characteristic calculation curve and the tangent equation, obtain the external characteristic fitting curve of the drive motor, including: According to the speed value of the drive motor corresponding to the intersection coordinates, determine the calculation coordinates corresponding to the speed value on the external characteristic calculation curve; Judge whether the error value between the intersection coordinates and the calculation coordinates is within the preset error range; When the error value is within the preset error range, determine the intersection coordinates as the fitting coordinates; Obtain the external characteristic fitting curve of the drive motor according to the fitting coordinates.

6. The method for determining the external characteristic parameters of a drive motor based on tangent fitting according to claim 5, characterized in that, When the error value is not within the preset error range, re-segment the external characteristic calculation curve and update the intersection coordinates; Calculate the error update value between the updated intersection coordinates and the calculation coordinates.

7. The method for determining the external characteristic parameters of a drive motor based on tangent fitting according to claim 1, characterized in that Determine the external characteristic parameters of the drive motor according to the external characteristic fitting curve, including: Obtain the speed measurement value of the drive motor, and determine the torque value of the drive motor at the speed measurement value according to the speed measurement value and the external characteristic fitting curve.

8. A device for determining the external characteristics of a drive motor based on tangent fitting, characterized in that, Including: A curve generation module, configured to obtain the interface parameters of the drive motor, and obtain the external characteristic calculation curve of the drive motor according to the interface parameters; A tangent equation generation module, configured to obtain the tangent equation according to the external characteristic calculation curve; A fitting curve generation module, configured to obtain the external characteristic fitting curve of the drive motor according to the external characteristic calculation curve and the tangent equation, and the formula of the external characteristic fitting curve of the drive motor is: ， Among them, is the rated power, is the rated torque, is the rated speed, is the speed of the drive motor, is the maximum speed. The rated speed to the maximum speed is divided into segments, is a positive integer, and the speed length of each segment , is the serial number of the speed length, and the value range is ∈[1, , represents the tangent slope of the th tangent point; The external characteristic parameter determination module is used to determine the external characteristic parameters of the drive motor according to the externally characteristic fitting curve.

9. An electronic device, characterized in that, It includes a processor and a memory, and a computer program is stored on the memory. When the computer program is executed by the processor, the method for determining the external characteristic parameters of the drive motor based on tangent fitting as described in any one of claims 1-7 is implemented.

10. A computer-readable storage medium, characterized in that, A computer program is stored thereon. When the computer program is executed by the processor, the method for determining the external characteristic parameters of the drive motor based on tangent fitting as described in any one of claims 1-7 is implemented.

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