Parameter determination method and device of induction motor and electronic equipment

Abstract

The application discloses a parameter determination method and device of an induction motor and electronic equipment. The method comprises the following steps: when the motor is not connected with a load, the excitation current of the motor is controlled to be the rated current of the motor; the target inflection point speed of the motor is determined according to the actual current of the motor at multiple different set speeds; the target speed of the motor is controlled to be the target inflection point speed, the excitation current of the motor is controlled to be the rated current, and the motor is controlled to operate at the target speed; the excitation current of the motor is gradually increased until the voltage of the motor is saturated, and the excitation current corresponding to the time when the motor reaches the voltage saturation is taken as the maximum excitation current of the motor; the target speed of the motor is controlled to be the target inflection point speed, the motor is controlled to operate at the target speed, the excitation current of the motor is gradually decreased, and the minimum excitation current of the motor is determined according to the excitation current corresponding to the time when the actual current of the motor remains unchanged. The technical scheme of the application improves the accuracy and applicability of the parameter determination of the induction motor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of induction motor, and particularly relates to a parameter determination method and device of an induction motor and electronic equipment. BACKGROUND

[0002] With the rapid development of battery energy storage and other technologies, electric vehicles are developing more and more rapidly, and the core power source of electric vehicles is a motor. The motor includes an induction motor, which has the characteristics of simple structure, low cost and high reliability, and is widely used in low-voltage electric vehicles at present.

[0003] The host factory will equip different motors according to the self-weight, voltage level and maximum load of the vehicle. Therefore, it is necessary to determine the parameters of different motors. The existing vehicle controller can only control the motor based on the parameters of one motor type, so that the applicability of the vehicle controller is poor. After replacing the motor type, it is necessary to rebuild the test environment to measure the parameters of the motor, so that the applicability of the motor parameter determination method is poor. Moreover, when rebuilding the test environment, the test environment changes, the parameters of the motor cannot be accurately determined, and the accuracy of the motor parameter determination is poor. SUMMARY

[0004] The present application provides a parameter determination method and device of an induction motor and electronic equipment to solve the problems of poor applicability and accuracy of the motor parameter determination method.

[0005] According to an aspect of the present application, a parameter determination method of an induction motor is provided, and the parameter determination method of the induction motor comprises the following steps.

[0006] When the motor is not connected to a load, the excitation current of the motor is controlled to be the rated current of the motor;

[0007] According to the actual current of the motor at a plurality of different set speeds, the target inflection point speed of the motor is determined; wherein the current change rate of the motor at the target inflection point speed is greater than the current change rate at the remaining set speeds;

[0008] The target speed of the motor is controlled to be the target inflection point speed, the excitation current of the motor is controlled to be the rated current, and the motor is controlled to operate at the target speed;

[0009] The excitation current of the motor is gradually increased according to a first current step value until the voltage of the motor is saturated, and the excitation current corresponding to the voltage saturation of the motor is taken as the maximum excitation current of the motor;

[0010] The target rotating speed of the motor is controlled to be the target inflection point rotating speed, and the motor is controlled to operate according to the target rotating speed, the excitation current of the motor is gradually reduced, and the minimum excitation current of the motor is determined according to the excitation current corresponding to the actual current of the motor when the actual current of the motor is maintained unchanged.

[0011] Optionally, the target inflection point rotating speed of the motor is determined according to the actual current of the motor at a plurality of different set rotating speeds, and the method comprises:

[0012] The rotating speed of the motor is gradually increased from the current minimum set rotating speed to the current maximum set rotating speed at a current step value, and the actual current of the motor at each set rotating speed is obtained;

[0013] The current change rate corresponding to each set rotating speed is determined according to the actual current corresponding to each two adjacent set rotating speeds, and the set rotating speed corresponding to the maximum current change rate is taken as the current inflection point rotating speed;

[0014] If the current step value is greater than a set threshold value, a next step value is determined according to the current step value and a step value, a next minimum set rotating speed and a next maximum set rotating speed are determined according to the current inflection point rotating speed, and the step of gradually increasing the rotating speed of the motor from the current minimum set rotating speed to the current maximum set rotating speed at a current step value and obtaining the actual current of the motor at each set rotating speed is executed again; wherein the next step value is less than the current step value, the current inflection point rotating speed is between the next minimum set rotating speed and the next maximum set rotating speed, the next minimum set rotating speed is greater than the current minimum set rotating speed, and the next maximum set rotating speed is less than the current maximum set rotating speed;

[0015] If the current step value is less than or equal to the set threshold value, the current inflection point rotating speed is taken as the target inflection point rotating speed.

[0016] Optionally, the excitation current of the motor is gradually reduced, and the minimum excitation current of the motor is determined according to the excitation current corresponding to the actual current of the motor when the actual current of the motor is maintained unchanged, and the method comprises:

[0017] The excitation current of the motor is gradually reduced at a second current step value, and the sum of the excitation current corresponding to the actual current of the motor when the actual current of the motor is maintained unchanged and the second current step value is taken as the minimum excitation current of the motor.

[0018] Optionally, after the minimum excitation current of the motor is determined according to the excitation current corresponding to the actual current of the motor when the actual current of the motor is maintained unchanged, the method further comprises:

[0019] The maximum torque current of the motor is determined according to the maximum excitation current and the maximum output current of the voltage circuit connected to the motor.

[0020] Optionally, determining the maximum torque current of the motor according to the maximum excitation current and the maximum output current of the voltage circuit connected with the motor, comprises:

[0021] Square the maximum output current, subtract the square of the maximum excitation current, and square the difference to obtain the maximum torque current.

[0022] Optionally, after determining the maximum torque current of the motor according to the maximum excitation current and the maximum output current of the voltage circuit connected with the motor, the method further comprises:

[0023] After the motor is connected with the load, and when the vehicle to which the motor belongs is in the air, gradually increasing the slip value of the motor from a minimum set slip value to a maximum set slip value by a first slip step value, and gradually increasing the rotating speed of the motor from zero to the maximum rotating speed of the motor according to a set acceleration at each set slip value; wherein the slip value of the motor is the difference between the rotating speed of the rotor and the rotating speed of the magnetic field of the motor.

[0024] Determining an initial slip range according to the set slip value corresponding to the time length that the motor gradually increases from zero to the maximum rotating speed and is less than a preset time length.

[0025] Determining a target slip value of the motor according to the initial slip range.

[0026] Optionally, determining a target slip value of the motor according to the initial slip range, comprises:

[0027] Gradually increasing the slip value of the motor from the minimum value of the initial slip range to the maximum value of the initial slip range by a second slip step value, and driving the vehicle to run under the same preset working condition at each slip value in the initial slip range.

[0028] Obtaining the actual rotating speed of the motor each time the motor drives the vehicle to run, and taking the slip value corresponding to the maximum value of all actual rotating speeds as the target slip value of the motor.

[0029] Optionally, the motor is a traction motor; and driving the motor to run under the same preset working condition, comprises:

[0030] Driving the motor to drive the vehicle to climb from a first preset position to a second preset position on the same slope.

[0031] Alternatively, the motor is a lifting motor; and driving the motor to run under the same preset working condition, comprises:

[0032] control the motor to drive the lifting mechanism of the vehicle to lift from a third preset position to a fourth preset position under the same load;

[0033] Alternatively, the motor is a traction and lifting motor; the motor is controlled to drive the vehicle to run under the same preset working condition, including:

[0034] control the motor to drive the vehicle to climb from a first preset position to a second preset position on the same slope, or control the motor to drive the lifting mechanism of the vehicle to lift from a third preset position to a fourth preset position under the same load.

[0035] According to another aspect of the present application, a parameter determination device of an induction motor is provided, which comprises:

[0036] The first motor control module is configured to control the excitation current of the motor to be the rated current of the motor when the motor is not connected to a load.

[0037] The target inflection point speed determination module is configured to determine the target inflection point speed of the motor according to the actual currents of the motor at a plurality of different set speeds; wherein the current change rate of the motor corresponding to the target inflection point speed is greater than the current change rates corresponding to the remaining set speeds.

[0038] The second motor control module is configured to control the target speed of the motor to be the target inflection point speed, control the excitation current of the motor to be the rated current, and control the motor to run at the target speed.

[0039] The maximum excitation current determination module is configured to gradually increase the excitation current of the motor according to a first current step value until the voltage of the motor saturates, and take the excitation current corresponding to the voltage saturation of the motor as the maximum excitation current of the motor.

[0040] The minimum excitation current determination module is configured to control the target speed of the motor to be the target inflection point speed, control the motor to run at the target speed, gradually decrease the excitation current of the motor, and determine the minimum excitation current of the motor according to the excitation current corresponding to the actual current of the motor remaining unchanged.

[0041] According to another aspect of the present application, an electronic device is provided, which comprises:

[0042] at least one processor; and

[0043] a memory connected in communication with the at least one processor; wherein

[0044] The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to perform the parameter determination method of the induction motor according to any one of the embodiments of the present application.

[0045] The technical scheme of the embodiment of the present application controls the excitation current of the motor to be the rated current of the motor when the motor is not connected with a load, determines the target inflection point speed of the motor according to the actual current of the motor at a plurality of different set speeds, controls the target speed of the motor to be the target inflection point speed, controls the excitation current of the motor to be the rated current, controls the motor to operate at the target speed, controls the excitation current of the motor to gradually increase according to a first current step value until the voltage of the motor is saturated, takes the excitation current corresponding to the time when the voltage of the motor is saturated as the maximum excitation current of the motor, controls the excitation current of the motor to gradually decrease, and determines the minimum excitation current of the motor according to the excitation current corresponding to the time when the actual current of the motor is maintained unchanged. Since the motor can achieve a larger torque value at the target inflection point speed, the torque of the motor decreases when the speed of the motor is greater than the target inflection point speed, and the excitation current of the motor continues to increase when the speed of the motor is greater than the target inflection point speed, which causes a larger additional power consumption. When the speed of the motor is less than the target inflection point speed, the motor can achieve a larger torque value, but the speed is smaller and the excitation current is also smaller. Therefore, controlling the target speed of the motor to be the target inflection point speed can determine the maximum excitation current of the motor and will not cause a larger additional power consumption, that is, controlling the target speed of the motor to be the target inflection point speed can determine a more appropriate maximum excitation current of the motor, thereby improving the accuracy of the parameter determination of the motor. Moreover, determining the minimum excitation current of the motor according to the excitation current corresponding to the time when the actual current of the motor is maintained unchanged can avoid that the minimum excitation current is too small to maintain the magnetic field of the motor. In this way, the parameters of the induction motor can be better determined, and the parameters of different induction motors can be determined, thereby improving the applicability of the parameter determination of the induction motor.

[0046] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creating laborious work.

[0048] Figure 1is a flow chart of a parameter determination method of an induction motor provided by an embodiment of the present application;

[0049] Figure 2 is a flow chart of another parameter determination method of an induction motor provided by an embodiment of the present application;

[0050] Figure 3 is a flow chart of still another parameter determination method of an induction motor provided by an embodiment of the present application;

[0051] Figure 4 is a flow chart of still another parameter determination method of an induction motor provided by an embodiment of the present application;

[0052] Figure 5 is a flow chart of still another parameter determination method of an induction motor provided by an embodiment of the present application;

[0053] Figure 6 is a structural schematic diagram of a parameter determination device of an induction motor provided by an embodiment of the present application;

[0054] Figure 7 is a structural schematic diagram of an electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0055] In order to make the personnel in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by the personnel in the art without creative labor should belong to the protection scope of the present application.

[0056] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0057] The embodiment of the present application provides a parameter determination method of an induction motor, the induction motor can be applied to a vehicle, the vehicle includes an electric vehicle, the electric vehicle includes an electric industrial vehicle, the electric industrial vehicle includes an electric forklift, an electric aerial platform and an electric dumper, etc. The parameters of the induction motor can include maximum excitation current and minimum excitation current of the induction motor.

[0058] Figure 1 is a flow chart of the parameter determination method of the induction motor provided by the embodiment of the present application, referring to Figure 1 , the parameter determination method of the induction motor includes:

[0059] S110, when the motor is not connected with a load, the excitation current of the motor is controlled to be a rated current of the motor.

[0060] The motor is an induction motor. The load can be a gearbox. The motor is not connected with the load, that is, the connection between the motor and the whole vehicle is disconnected, so that the motor is in a no-load state. The rated current of the motor is the rated current marked on the motor when the motor is shipped, which is the rated line current of the motor.

[0061] Specifically, when the motor is not connected with the load, the excitation current of the motor is controlled to be the rated current of the motor, so that the change trend of the current of the motor with the rotating speed of the motor can be determined when the excitation current of the motor is the rated current, thereby avoiding that the excitation current is too small or too large, and facilitating accurate determination of the target inflection point rotating speed of the motor. If the excitation current is too small, the determined target inflection point rotating speed can be too small, if the excitation current is greater than the rated current, the excitation current is too large, and the operation of the motor is affected.

[0062] S120, according to actual currents of the motor at a plurality of different set rotating speeds, a target inflection point rotating speed of the motor is determined, wherein a current change rate corresponding to the target inflection point rotating speed of the motor is greater than current change rates corresponding to the remaining set rotating speeds.

[0063] Specifically, when the excitation current of the motor is the rated current, a plurality of different set rotating speeds are set, the motor is controlled to operate according to the set rotating speeds, and actual currents corresponding to each set rotating speed of the motor are detected. The current change rate corresponding to each set rotating speed of the motor can be determined. For example, the actual current of the motor when operating at the nth set rotating speed is , the actual current of the motor when operating at the (n+1)th set rotating speed is , the difference between the (n+1)th set rotating speed and the nth set rotating speed is a, and the current change rate corresponding to the (n+1)th set rotating speed is n is a positive integer. For example, the difference between any two adjacent set rotating speeds is the same, and the current change rate corresponding to the first set rotating speed can be the ratio of the actual current at the first set rotating speed to a.

[0064] During the operation of the motor, with the increase of the motor speed, the motor first has constant torque and then has constant power. That is, during the operation of the motor, with the increase of the motor speed, the torque of the motor is relatively stable at first, and then suddenly changes greatly when the motor speed increases to a certain value (inflection point speed), and then decreases with the increase of the motor speed. Therefore, the target inflection point speed can be determined according to the current change rate. For example, the set speed corresponding to the maximum value of all current change rates is the target inflection point speed of the motor, that is, the current change rate corresponding to the target inflection point speed of the motor is greater than the current change rate corresponding to the remaining set speeds.

[0065] In S130, the target speed of the motor is controlled to be the target inflection point speed, the excitation current of the motor is controlled to be the rated current, and the motor is controlled to operate at the target speed.

[0066] Specifically, since the motor can achieve a larger torque value at the target inflection point speed, the torque of the motor decreases when the speed of the motor is greater than the target inflection point speed, and the excitation current of the motor continues to increase when the speed of the motor is greater than the target inflection point speed, which will cause a larger additional power consumption. When the speed of the motor is less than the target inflection point speed, the motor can achieve a larger torque value, but the speed is relatively small and the excitation current is also relatively small. Therefore, controlling the target speed of the motor to be the target inflection point speed makes the motor operate at the target inflection point speed as the target, which can determine the maximum excitation current of the motor and will not cause a larger additional power consumption, that is, controlling the target speed of the motor to be the target inflection point speed can determine a more appropriate maximum excitation current of the motor. Controlling the motor to operate at the target speed, that is, controlling the actual speed of the motor to operate at the target speed, makes the speed of the motor reach the target inflection point speed. Controlling the excitation current of the motor to be the rated current makes the voltage of the motor be the rated voltage.

[0067] It should be noted that if the voltage of the motor does not reach the rated voltage when the excitation current of the motor is the rated current, the excitation current can be adjusted so that the voltage of the motor is the rated voltage, and in the subsequent process, the excitation current of the motor starts to increase according to the adjusted excitation current.

[0068] In S140, the excitation current of the motor is gradually increased according to the first current step value until the voltage of the motor is saturated, and the excitation current corresponding to the voltage saturation of the motor is taken as the maximum excitation current of the motor.

[0069] Specifically, the excitation current of the motor is gradually increased from the rated current (or the adjusted rated current) according to the first current step value, and at each excitation current, the motor voltage of the motor, i.e., the voltage between any two phases of the motor, is obtained. The excitation current corresponding to the time when the motor voltage reaches saturation (i.e., the voltage does not increase even if the excitation current of the motor continues to increase) is taken as the maximum excitation current of the motor.

[0070] By determining the maximum excitation current of the motor, the maximum excitation current can be transmitted to the controller of the vehicle. When the motor is running, the controller of the vehicle can control the excitation current of the motor to be less than the maximum excitation current in the control process of the motor, so as to avoid excessive excitation current and cause large additional power consumption of the motor, thereby achieving better control of the motor running and further better control of the vehicle running.

[0071] S150, the target speed of the motor is controlled to be the target inflection point speed, and the motor is controlled to run at the target speed, the excitation current of the motor is gradually reduced, and the minimum excitation current of the motor is determined according to the excitation current corresponding to the time when the actual current of the motor is maintained unchanged.

[0072] Specifically, the target speed of the motor is still controlled to be the target inflection point speed, and the motor is controlled to run at the target speed. Since the excitation current of the motor is adjusted too large in step S140, the excitation current of the motor is gradually reduced. When the excitation current of the motor is gradually reduced, the actual current of the motor is gradually reduced until the actual current of the motor is maintained unchanged. If the excitation current continues to decrease, the magnetic field of the motor cannot be maintained. Therefore, the minimum excitation current of the motor can be determined according to the excitation current corresponding to the time when the actual current of the motor is maintained unchanged.

[0073] By determining the minimum excitation current of the motor, the determined minimum excitation current can be transmitted to the controller of the vehicle. When the motor is running, the controller of the vehicle can control the excitation current of the motor to be greater than the minimum excitation current of the motor in the control process of the motor, so as to ensure that the motor can run normally and the actual speed of the motor can reach the target inflection point speed, i.e., the torque of the motor can be large, thereby achieving better control of the motor running and further better control of the vehicle running.

[0074] The technical scheme of the embodiment determines the target inflection point speed of the motor according to the actual current of the motor at multiple different set speeds, controls the target speed of the motor to be the target inflection point speed, controls the excitation current of the motor to be the rated current, controls the excitation current of the motor to gradually increase according to the first current step value until the voltage of the motor is saturated, takes the excitation current corresponding to the time when the voltage of the motor is saturated as the maximum excitation current of the motor, controls the excitation current of the motor to gradually decrease, and determines the minimum excitation current of the motor according to the excitation current corresponding to the time when the actual current of the motor remains unchanged. Since the motor can achieve a larger torque value at the target inflection point speed, the torque of the motor decreases when the speed of the motor is greater than the target inflection point speed, and the excitation current of the motor continues to increase when the speed of the motor is greater than the target inflection point speed, which causes a larger additional power consumption. When the speed of the motor is less than the target inflection point speed, the motor can achieve a larger torque value, but the speed is smaller and the excitation current is also smaller. Therefore, controlling the target speed of the motor to be the target inflection point speed can determine the maximum excitation current of the motor and will not cause a larger additional power consumption, that is, controlling the target speed of the motor to be the target inflection point speed can determine a more appropriate maximum excitation current of the motor, thereby improving the accuracy of motor parameter determination. Moreover, determining the minimum excitation current of the motor according to the excitation current corresponding to the time when the actual current of the motor remains unchanged can avoid that the minimum excitation current is too small to maintain the magnetic field of the motor. In this way, the parameters of the induction motor can be better determined, and the parameters of different induction motors can be determined, thereby improving the applicability of induction motor parameter determination.

[0075] On the basis of the above technical scheme, Figure 2 is a flowchart of another induction motor parameter determination method provided by the embodiment of the application, and optionally, reference can be made to Figure 2 The induction motor parameter determination method comprises the following steps.

[0076] S210, when the motor is not connected to a load, controlling the excitation current of the motor to be the rated current of the motor.

[0077] S220, controlling the speed of the motor to gradually increase from the current minimum set speed to the current maximum set speed according to the current step value, and obtaining the actual current of the motor at each set speed.

[0078] Specifically, the current step value is a step value of the set speed, the speed of the motor is controlled to gradually increase from the current minimum set speed to the current maximum set speed according to the current step value, so that the motor operates at multiple set speeds, and the actual current of the motor when operating at each set speed can be obtained.

[0079] For example, in the first time of controlling the rotating speed of the motor to gradually increase from the current minimum set rotating speed to the current maximum set rotating speed, the current step value is 200 rpm, the current minimum set rotating speed is 200 rpm, the current maximum set rotating speed is the maximum rotating speed Vmax that the motor can reach (the maximum rotating speed marked when the motor is shipped), and the actual current of the motor when the motor runs at each set rotating speed is obtained. Table 1 is a corresponding relationship table between the rotating speed of the motor and the actual current of the motor provided by the embodiment of the present application. As shown in Table 1, when the rotating speed of the motor is set to 200 rpm, the actual current of the motor is A11; when the rotating speed of the motor is set to 400 rpm, the actual current of the motor is A12; when the rotating speed of the motor is set to 600 rpm, the actual current of the motor is A13; when the rotating speed of the motor is set to 800 rpm, the actual current of the motor is A14; when the rotating speed of the motor is set to 1000 rpm, the actual current of the motor is A15; when the rotating speed of the motor is set to 1200 rpm, the actual current of the motor is A16; when the rotating speed of the motor is set to 1400 rpm, the actual current of the motor is A17; and when the rotating speed of the motor is set to Vmax, the actual current of the motor is Am.

[0080] Table 1 is a corresponding relationship table between the rotating speed of the motor and the actual current of the motor provided by the embodiment of the present application.

[0081]

[0082] For example, in the second time of controlling the rotating speed of the motor to gradually increase from the current minimum set rotating speed to the current maximum set rotating speed, the current step value is 50 rpm, the current minimum set rotating speed is 800 rpm, the current maximum set rotating speed is 1400 rpm, and the actual current of the motor when the motor runs at each set rotating speed is obtained. Table 2 is another corresponding relationship table between the rotating speed of the motor and the actual current of the motor provided by the embodiment of the present application. As shown in Table 2, when the rotating speed of the motor is set to 800 rpm, the actual current of the motor is A21; when the rotating speed of the motor is set to 850 rpm, the actual current of the motor is A22; when the rotating speed of the motor is set to 900 rpm, the actual current of the motor is A23; when the rotating speed of the motor is set to 950 rpm, the actual current of the motor is A24; when the rotating speed of the motor is set to 1000 rpm, the actual current of the motor is A25; when the rotating speed of the motor is set to 1050 rpm, the actual current of the motor is A26; when the rotating speed of the motor is set to 1100 rpm, the actual current of the motor is A27; and when the rotating speed of the motor is set to 1400 rpm, the actual current of the motor is Ax.

[0083] Table 2 is another corresponding relationship table between the rotating speed of the motor and the actual current of the motor provided by the embodiment of the present application.

[0084]

[0085] S230, determining a current change rate corresponding to each set speed according to the actual current corresponding to each two adjacent set speeds, and taking the set speed corresponding to the maximum current change rate as the current inflection point speed.

[0086] Specifically, the difference between the two adjacent set speeds is the current step value. The difference between the actual current corresponding to one set speed and the actual current corresponding to the previous set speed can be divided by the current step value to obtain the current change rate corresponding to the set speed. The current change rate corresponding to the first set speed can be the ratio of the actual current at the first set speed to the current step value. In this way, the current change rate corresponding to each set speed can be determined, and the set speed corresponding to the maximum current change rate is taken as the current inflection point speed, that is, the set speed corresponding to the maximum current change rate is taken as the current inflection point speed.

[0087] For example, according to the actual current of the motor shown in Table 1, the current change rate corresponding to each set speed is determined, and it is determined that the set speed corresponding to the maximum current change rate is 1200 rpm, so the current inflection point speed is 1200 rpm. For example, according to the actual current of the motor shown in Table 2, the current change rate corresponding to each set speed is determined, and it is determined that the set speed corresponding to the maximum current change rate is 1100 rpm, so the current inflection point speed is 1100 rpm.

[0088] S240, determining whether the current step value is greater than a set threshold, if yes, executing step S250, and if no, executing step S260.

[0089] Specifically, the set threshold can be a value close to 0, for example, any value between 10 rpm and 50 rpm, for example, 20 rpm or 50 rpm, etc. After obtaining the current inflection point speed each time, it is determined whether the current step value is greater than the set threshold.

[0090] S250, determining a next step value according to the current step value and a step value, determining a next minimum set speed and a next maximum set speed according to the current inflection point speed, and returning to execute step S220; wherein the next step value is less than the current step value, the current inflection point speed is between the next minimum set speed and the next maximum set speed; the next minimum set speed is greater than the current minimum set speed, and the next maximum set speed is less than the current maximum set speed.

[0091] Specifically, when the current step value is greater than the set threshold value, the next step value is determined according to the current step value and the step value, that is, the current step value is subtracted by the step value to obtain the next step value, so that the next step value is less than the current step value. It is known that the next step value is the current step value in the next execution of step S220.

[0092] The next minimum set speed and the next maximum set speed are determined according to the current inflection point speed, and the current inflection point speed is between the next minimum set speed and the next maximum set speed, the next minimum set speed is greater than the current minimum set speed, and the next maximum set speed is less than the current maximum set speed, that is, the range of the set speed determined for the next execution of step S220 is smaller than the range of the set speed for the current execution of step S220, and the range of the set speed for the next execution of step S220 contains the current inflection point speed. In this way, the range of the set speed can be reduced, so that the error between the determined target inflection point speed and the real inflection point speed is small, and a more accurate target inflection point speed can be determined. When the current step value is less than or equal to the set threshold value, the error of the determined target inflection point speed is less than the set threshold value, thereby improving the accuracy of the determination of the target inflection point speed.

[0093] For example, the next step value determined according to the current step value and the step value is 50 rpm, for example, the current inflection point speed is 1200 rpm, the next minimum set speed is 800 rpm, and the next maximum set speed is 1400 rpm. Continue to return to execute step S220, the corresponding relationship between the speed of the motor and the actual current of the motor shown in Table 2 can be obtained, that is, the actual current corresponding to each set speed is determined.

[0094] S260, the current inflection point speed is taken as the target inflection point speed; wherein the current change rate of the motor at the target inflection point speed is greater than the current change rate of the motor at the remaining set speeds.

[0095] Specifically, when the current step value is less than or equal to the set threshold value, the current inflection point speed is taken as the target inflection point speed, so that the error of the determined target inflection point speed is less than the set threshold value, and the error between the determined target inflection point speed and the real inflection point speed is small, thereby improving the accuracy of the determination of the target inflection point speed. Thus, more accurate maximum excitation current and minimum excitation current can be determined according to the target inflection point speed, which is beneficial to improve the accuracy of the parameter determination of the induction motor. For example, when the set threshold value is 50 rpm and the current step value is 50 rpm, the set speed corresponding to the maximum current change rate is 1100 rpm, that is, the current inflection point speed is 1100 rpm, and the target inflection point speed is 1100 rpm.

[0096] S270, the target speed of the motor is controlled to be the target inflection point speed, the excitation current of the motor is controlled to be the rated current, and the motor is controlled to operate at the target speed.

[0097] S280, the excitation current of the motor is gradually increased according to the first current step value until the voltage of the motor is saturated, and the excitation current corresponding to the time when the voltage of the motor is saturated is taken as the maximum excitation current of the motor.

[0098] S290, the target speed of the motor is controlled to be the target inflection point speed, the motor is controlled to operate at the target speed, and the excitation current of the motor is gradually reduced, and the minimum excitation current of the motor is determined according to the excitation current corresponding to the time when the actual current of the motor is maintained unchanged.

[0099] On the basis of each of the above technical solutions, the excitation current of the motor is gradually reduced, and the minimum excitation current of the motor is determined according to the excitation current corresponding to the time when the actual current of the motor is maintained unchanged, and the minimum excitation current of the motor is determined.

[0100] The excitation current of the motor is gradually reduced according to the second current step value, and the sum of the excitation current corresponding to the time when the actual current of the motor is maintained unchanged and the second current step value is taken as the minimum excitation current of the motor.

[0101] Specifically, the excitation current of the motor is gradually reduced according to the second current step value until, after reducing the excitation current of the motor at a certain time, the actual current of the motor no longer changes, and if the excitation current is continuously reduced, the motor enters an under-excited state, resulting in a large increase in the torque current of the motor (because a larger torque current is needed to compensate for the torque drop caused by insufficient magnetic flux), thereby increasing the actual current of the motor, i.e., if the excitation current is further reduced after the actual current of the motor is maintained unchanged, the excitation current will be too small, and the previous excitation current of the excitation current corresponding to the time when the actual current of the motor is maintained unchanged is taken as the minimum excitation current of the motor. That is, at the previous excitation current of the excitation current corresponding to the time when the actual current of the motor is maintained unchanged, the actual current of the motor can still change according to the change of the excitation current, i.e., the previous excitation current of the excitation current corresponding to the time when the actual current of the motor is maintained unchanged is the minimum excitation current that can ensure the normal operation of the motor, i.e., the minimum excitation current. The previous excitation current of the excitation current corresponding to the time when the actual current of the motor is maintained unchanged is the sum of the excitation current corresponding to the time when the actual current of the motor is maintained unchanged and the second current step value.

[0102] On the basis of each of the above technical solutions, Figure 3 is a flowchart of another parameter determination method of an induction motor provided by an embodiment of the present application, and optionally, reference is made to Figure 3 , the parameter determination method of the induction motor comprises:

[0103] S310, control the excitation current of the motor to be the rated current of the motor when the motor is not connected with a load.

[0104] S320, control the rotating speed of the motor to gradually increase from the current minimum set rotating speed to the current maximum set rotating speed with the current step value, and obtain the actual current of the motor at each set rotating speed.

[0105] S330, determine the current change rate corresponding to each set rotating speed according to the actual current corresponding to each two adjacent set rotating speeds, and take the set rotating speed corresponding to the maximum current change rate as the current inflection point rotating speed.

[0106] S340, judge whether the current step value is greater than a set threshold, if yes, execute step S350, and if not, execute step S360.

[0107] S350, determine the next step value according to the current step value and the step value, determine the next minimum set rotating speed and the next maximum set rotating speed according to the current inflection point rotating speed, and return to execute step S320; wherein the next step value is less than the current step value, the current inflection point rotating speed is between the next minimum set rotating speed and the next maximum set rotating speed, the next minimum set rotating speed is greater than the current minimum set rotating speed, and the next maximum set rotating speed is less than the current maximum set rotating speed.

[0108] S360, take the current inflection point rotating speed as the target inflection point rotating speed; wherein the current change rate corresponding to the target inflection point rotating speed is greater than the current change rate corresponding to the remaining set rotating speeds.

[0109] S370, control the target rotating speed of the motor to be the target inflection point rotating speed, control the excitation current of the motor to be the rated current, and control the motor to operate at the target rotating speed.

[0110] S380, control the excitation current of the motor to gradually increase with a first current step value until the voltage of the motor is saturated, and take the excitation current corresponding to the voltage saturation of the motor as the maximum excitation current of the motor.

[0111] S390, control the target rotating speed of the motor to be the target inflection point rotating speed, control the motor to operate at the target rotating speed, and control the excitation current of the motor to gradually decrease with a second current step value, take the sum of the excitation current corresponding to the case that the actual current of the motor is maintained and the second current step value as the minimum excitation current of the motor.

[0112] S391, determine the maximum torque current of the motor according to the maximum excitation current and the maximum output current of the voltage circuit connected with the motor.

[0113] Specifically, the motor is connected with a voltage circuit, and the voltage circuit can be an inverter circuit converting direct current into three-phase alternating current to supply power to the motor. The maximum excitation current is the maximum current corresponding to the d-axis (direct axis), the maximum torque current is the maximum current corresponding to the q-axis (quadrature axis), and the maximum output current of the voltage circuit is the line current. Therefore, the maximum torque current of the motor can be determined according to the relationship between the coordinate systems, the maximum excitation current and the maximum output current of the voltage circuit connected with the motor.

[0114] In this way, the determined maximum torque current can be transmitted to the controller of the vehicle, so that when the motor is running, the controller of the vehicle controls the torque current of the motor to be less than the maximum torque current of the motor in the process of controlling the motor, thereby avoiding excessive torque current.

[0115] On the basis of the above technical solutions, the maximum torque current of the motor can be determined according to the maximum excitation current and the maximum output current of the voltage circuit connected with the motor, including:

[0116] The square value of the maximum output current is subtracted from the square value of the maximum excitation current, and the square root of the difference is obtained to obtain the maximum torque current.

[0117] For example, the maximum output current is , the maximum excitation current is , and the maximum torque current is , then , then . In this way, the maximum torque current of the motor can be determined according to the maximum excitation current and the maximum output current of the voltage circuit connected with the motor.

[0118] On the basis of the above technical solutions, Figure 4 is a flowchart of another parameter determination method of an induction motor provided by an embodiment of the present application, and optionally, reference is made to Figure 4 The parameter determination method of the induction motor includes:

[0119] S410, when the motor is not connected with a load, the excitation current of the motor is controlled to be the rated current of the motor.

[0120] S420, the speed of the motor is controlled to gradually increase from the current minimum set speed to the current maximum set speed at the current step value, and the actual current of the motor at each set speed is obtained.

[0121] S430, according to the actual currents corresponding to each two adjacent set speeds, the current change rate corresponding to each set speed is determined, and the set speed corresponding to the maximum current change rate is taken as the current inflection point speed.

[0122] S440, determine whether the current step value is greater than a set threshold value, if yes, execute step S450; if no, execute step S460.

[0123] S450, determine a next step value according to the current step value and the step value, determine a next minimum set speed and a next maximum set speed according to the current inflection point speed, and return to execute step S420; wherein the next step value is less than the current step value, the current inflection point speed is between the next minimum set speed and the next maximum set speed; the next minimum set speed is greater than the current minimum set speed, and the next maximum set speed is less than the current maximum set speed.

[0124] S460, take the current inflection point speed as a target inflection point speed; wherein the current change rate of the motor at the target inflection point speed is greater than the current change rate of the motor at the remaining set speeds.

[0125] S470, control the target speed of the motor to be the target inflection point speed, control the excitation current of the motor to be the rated current, and control the motor to operate at the target speed.

[0126] S480, control the excitation current of the motor to gradually increase according to a first current step value until the voltage of the motor is saturated, and take the excitation current corresponding to the voltage saturation of the motor as the maximum excitation current of the motor.

[0127] S490, control the target speed of the motor to be the target inflection point speed, control the motor to operate at the target speed, and control the excitation current of the motor to gradually decrease according to a second current step value, and take the sum of the excitation current corresponding to the actual current of the motor being maintained unchanged and the second current step value as the minimum excitation current of the motor.

[0128] S491, determine the maximum torque current of the motor according to the maximum excitation current and the maximum output current of the voltage circuit connected to the motor.

[0129] S492, after the motor is connected to the load, and when the vehicle where the motor is located is in the air, control the slip value of the motor to gradually increase from the minimum set slip value to the maximum set slip value at a first slip step value, and at each set slip value, control the speed of the motor to gradually increase from zero to the maximum speed of the motor at a set acceleration; wherein the slip value of the motor is the difference between the rotor speed and the magnetic field speed of the motor.

[0130] For example, the set acceleration is the maximum acceleration that the motor can reach, that is, the maximum acceleration marked when the motor is shipped. The maximum speed of the motor is the maximum speed marked when the motor is shipped.

[0131] Specifically, after the motor is connected with the load (for example, a gearbox), the motor is connected with the whole vehicle, but the vehicle is not moving forward or backward. The slip value of the motor is gradually increased from the minimum set slip value to the maximum set slip value at the first slip step value, that is, the motor is at a plurality of different set slip values, and the slip value of the motor is gradually increased, and when the motor is at each set slip value, the speed of the motor is gradually increased from zero to the maximum speed of the motor at the set acceleration.

[0132] S493, determining the initial slip range according to the set slip value corresponding to the time length when the motor gradually increases from zero to the maximum speed and is less than the preset time length.

[0133] Specifically, the set slip value corresponding to the time length when the motor gradually increases from zero to the maximum speed and is less than the preset time length is the set slip value meeting the demand, and there are a plurality of continuous set slip values among all the set slip values meeting the demand. The slip range formed by the plurality of continuous set slip values among all the set slip values meeting the demand is taken as the initial slip range. Therefore, when the slip value of the motor is in the initial slip range, the motor accelerates faster. For example, the first slip step value is d0, all the set slip values are d1, d1+d0, d1+2d0, d1+3d0, d1+4d0, d1+5d0, d1+6d0 and d1+7d0, and when the slip value of the motor is d1+2d0, d1+5d0, d1+6d0 and d1+7d0, the time length when the motor gradually increases from zero to the maximum speed is less than the preset time length, that is, all the set slip values meeting the demand are d1+2d0, d1+5d0, d1+6d0 and d1+7d0, and the plurality of continuous set slip values among all the set slip values meeting the demand are d1+5d0, d1+6d0 and d1+7d0. Therefore, the initial slip range is d1+5d0 to d1+7d0, and the initial slip range is determined.

[0134] S494, determining the target slip value of the motor according to the initial slip range.

[0135] Specifically, when the slip value of the motor is in the initial slip range, the motor accelerates faster. Therefore, any slip value in the initial slip range can be taken as the target slip value of the motor, or the slip value corresponding to the higher efficiency of the motor in the initial slip range can be taken as the target slip value of the motor. In this way, the determined target slip value can ensure that the motor accelerates faster and has higher efficiency when it is actually running.

[0136] On the basis of the above technical solutions, Figure 5 is a flowchart of another parameter determination method of an induction motor provided by an embodiment of the present application. Optionally, reference can be made to Figure 5 The parameter determination method of the induction motor comprises the following steps.

[0137] S510, control the excitation current of the motor to be the rated current of the motor when the motor is not connected with a load.

[0138] S520, control the rotating speed of the motor to gradually increase from the current minimum set rotating speed to the current maximum set rotating speed with the current step value, and obtain the actual current of the motor at each set rotating speed.

[0139] S530, determine the current change rate corresponding to each set rotating speed according to the actual current corresponding to each two adjacent set rotating speeds, and take the set rotating speed corresponding to the maximum current change rate as the current inflection point rotating speed.

[0140] S540, judge whether the current step value is greater than a set threshold, if yes, execute step S550, and if no, execute step S560.

[0141] S550, determine the next step value according to the current step value and the step value, determine the next minimum set rotating speed and the next maximum set rotating speed according to the current inflection point rotating speed, and return to execute step S520; wherein the next step value is less than the current step value, the current inflection point rotating speed is between the next minimum set rotating speed and the next maximum set rotating speed, the next minimum set rotating speed is greater than the current minimum set rotating speed, and the next maximum set rotating speed is less than the current maximum set rotating speed.

[0142] S560, take the current inflection point rotating speed as the target inflection point rotating speed; wherein the current change rate corresponding to the target inflection point rotating speed is greater than the current change rate corresponding to the remaining set rotating speeds.

[0143] S570, control the target rotating speed of the motor to be the target inflection point rotating speed, control the excitation current of the motor to be the rated current, and control the motor to operate at the target rotating speed.

[0144] S580, control the excitation current of the motor to gradually increase according to a first current step value until the voltage of the motor is saturated, and take the excitation current corresponding to the voltage saturation of the motor as the maximum excitation current of the motor.

[0145] S590, control the target rotating speed of the motor to be the target inflection point rotating speed, control the motor to operate at the target rotating speed, and control the excitation current of the motor to gradually decrease according to a second current step value, take the sum of the excitation current corresponding to the actual current of the motor being maintained and the second current step value as the minimum excitation current of the motor.

[0146] S591, determine the maximum torque current of the motor according to the maximum excitation current and the maximum output current of the voltage circuit connected with the motor.

[0147] S592, after the motor is connected with the load and the vehicle where the motor is located is in the air, gradually increasing the slip value of the motor from the minimum set slip value to the maximum set slip value by the first slip step value, and gradually increasing the rotating speed of the motor from zero to the maximum rotating speed of the motor according to the set acceleration at each set slip value, wherein the slip value of the motor is the difference between the rotating speed of the rotor of the motor and the rotating speed of the magnetic field.

[0148] S593, determining the initial slip range according to the set slip value corresponding to the time length when the motor gradually increases from zero to the maximum rotating speed and is less than the preset time length.

[0149] S594, gradually increasing the slip value of the motor from the minimum value of the initial slip range to the maximum value of the initial slip range by the second slip step value, and driving the vehicle to run in the same preset working condition at each slip value in the initial slip range.

[0150] Specifically, the slip value of the motor is gradually increased from the minimum value of the initial slip range to the maximum value of the initial slip range by the second slip step value, for example, the second slip step value is b, the minimum value of the initial slip range is c1, the maximum value of the initial slip range is c2, and the slip value of the motor is c1, c1+b, c1+2b, …, c2, respectively. And driving the vehicle to run in the same preset working condition at each slip value in the initial slip range, for example, driving the vehicle to climb on the same slope, or driving the vehicle to walk in the same flat area, or driving the lifting mechanism of the vehicle to lift under the same load, etc., which is not limited here. In this way, the target slip value of the motor can be determined according to the working condition of the motor in actual application, so that the determined target slip value is more accurate, further improving the accuracy of the parameter determination of the induction motor.

[0151] S595, obtaining the actual rotating speed of the motor when driving the vehicle to run each time, and taking the slip value corresponding to the maximum value of all actual rotating speeds as the target slip value of the motor.

[0152] Specifically, driving the vehicle to run in the same preset working condition at each slip value in the initial slip range, and obtaining the actual rotating speed of the motor when running at each slip value in the initial slip range, and taking the slip value corresponding to the maximum value of all actual rotating speeds as the target slip value of the motor. In this way, the determined target slip value can ensure that the rotating speed of the motor is high when the motor is actually running, thereby improving the operating efficiency of the motor.

[0153] On the basis of the above technical solutions, the motor is a traction motor, and driving the vehicle to run in the same preset working condition comprises:

[0154] control the motor to drive the vehicle to climb from a first preset position to a second preset position on the same slope;

[0155] Alternatively, the motor is a lifting motor; the motor is controlled to drive the vehicle to run in the same preset working condition, including:

[0156] under the same load, the motor is controlled to drive the lifting mechanism of the vehicle to lift from a third preset position to a fourth preset position;

[0157] Alternatively, the motor is a traction and lifting motor; the motor is controlled to drive the vehicle to run in the same preset working condition, including:

[0158] control the motor to drive the vehicle to climb from a first preset position to a second preset position on the same slope, or, under the same load, control the motor to drive the lifting mechanism of the vehicle to lift from a third preset position to a fourth preset position.

[0159] Specifically, if the motor is a traction motor, i.e., a motor that drives the vehicle to move forward, backward, and turn, etc., the motor can be controlled to drive the vehicle to climb from a first preset position to a second preset position on the same slope, i.e., at each slip value in the initial slip range of the motor, the motor is controlled to drive the vehicle to climb from the first preset position to the second preset position on the same slope, so as to realize the motor running in the same working condition. At each slip value in the initial slip range of the motor, the actual speed of the motor when the motor stably runs while driving the vehicle to climb from the first preset position to the second preset position on the same slope is obtained, and the slip value corresponding to the maximum value of all actual speeds is taken as the target slip value of the motor, so that the running efficiency of the motor is higher. For example, the first preset position can be the bottom of the slope, and the second preset position can be the top of the slope. The first preset position and the second preset position can also be other positions, which are not limited herein.

[0160] If the motor is a lifting motor, i.e., a motor that drives the lifting mechanism of the vehicle to lift, the motor can be controlled to drive the lifting mechanism of the vehicle to lift from a third preset position to a fourth preset position under the same load, i.e., at each slip value in the initial slip range of the motor, the motor is controlled to drive the lifting mechanism of the vehicle to lift from the third preset position to the fourth preset position under the same load. At each slip value in the initial slip range of the motor, the actual speed of the motor when the motor stably runs while driving the lifting mechanism of the vehicle to lift from the third preset position to the fourth preset position under the same load is obtained, and the slip value corresponding to the maximum value of all actual speeds is taken as the target slip value of the motor, so that the running efficiency of the motor is higher. The third preset position can be the lowest point of the lifting mechanism, and the fourth preset position can be the position corresponding to the lifting of the lifting mechanism by a preset height. The third preset position and the fourth preset position can also be other positions, which are not limited herein.

[0161] If the motor has both traction function and function of driving the lifting mechanism to lift, the motor can be controlled to drive the vehicle to move or to drive the lifting mechanism to lift, i.e., the motor is controlled to drive the vehicle to move from the first preset position to the second preset position on the same slope, or the motor is controlled to drive the lifting mechanism of the vehicle to lift from the third preset position to the fourth preset position under the same load, which is not limited herein.

[0162] The embodiment of the present application further provides a parameter determination device of an induction motor, Figure 6 is a structural schematic diagram of the parameter determination device of the induction motor provided by the embodiment of the present application, referring to Figure 6 The parameter determination device of the induction motor comprises:

[0163] The first motor control module 101 is used for controlling the excitation current of the motor to be the rated current of the motor when the motor is not connected with a load.

[0164] The target inflection point rotating speed determination module 102 is used for determining the target inflection point rotating speed of the motor according to the actual currents of the motor under a plurality of different set rotating speeds, wherein the current variation rate of the motor corresponding to the target inflection point rotating speed is greater than the current variation rates corresponding to the remaining set rotating speeds.

[0165] The second motor control module 103 is used for controlling the target rotating speed of the motor to be the target inflection point rotating speed, controlling the excitation current of the motor to be the rated current, and controlling the motor to operate at the target rotating speed.

[0166] The maximum excitation current determination module 104 is used for gradually increasing the excitation current of the motor according to a first current step value until the voltage of the motor is saturated, and taking the excitation current corresponding to the voltage saturation of the motor as the maximum excitation current of the motor.

[0167] The minimum excitation current determination module 105 is used for controlling the target rotating speed of the motor to be the target inflection point rotating speed, controlling the motor to operate at the target rotating speed, gradually reducing the excitation current of the motor, and determining the minimum excitation current of the motor according to the excitation current corresponding to the actual current of the motor remaining unchanged.

[0168] The parameter determination device of the induction motor provided by the embodiment of the present application can execute the parameter determination method of the induction motor provided by any embodiment of the present application, and has the function modules and beneficial effects corresponding to the execution method.

[0169] The embodiment of the present application further provides an electronic device, Figure 7 is a structural schematic diagram of the electronic device provided by the embodiment of the present application. Figure 7A structural diagram of an electronic device 10 that can be used to implement embodiments of the present application is shown. The electronic device is intended to represent various forms of digital computers, such as laptops, desktops, tablets, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The electronic device can also represent various forms of mobile devices, such as personal digital assistants, cellular telephones, smartphones, wearable devices (e.g., headsets, glasses, watches, etc.), and other similar computing devices. The components shown here, their connections and relationships, and their functions, are meant to be examples only, and are not intended to limit the implementations of the present application described and / or claimed in this document.

[0170] As shown in Figure 7 The electronic device 10 includes at least one processor 11, and a memory, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., connected in communication with the at least one processor 11, where the memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes according to the computer programs stored in the read-only memory (ROM) 12 or loaded into the random access memory (RAM) 13 from the storage unit 18. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0171] A plurality of components in the electronic device 10 are connected to the I / O interface 15, including an input unit 16, such as a keyboard, a mouse, etc., an output unit 17, such as various types of displays, speakers, etc., a storage unit 18, such as a magnetic disk, an optical disk, etc., and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network, such as the Internet, and / or various telecommunication networks.

[0172] The processor 11 can be various general and / or special-purpose processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 performs various methods and processes described above, such as the parameter determination method for an induction motor.

[0173] In some embodiments, the parameter determination method of an induction motor can be implemented as a computer program tangibly embodied in a computer readable storage medium, e.g., storage unit 18. In some embodiments, parts or all of the computer program can be loaded and / or installed onto electronic device 10 via, e.g., ROM 12 and / or communication unit 19. When the computer program is loaded onto RAM 13 and executed by processor 11, one or more steps of the parameter determination method of an induction motor described above can be performed. Alternatively, in other embodiments, processor 11 can be configured to perform the parameter determination method of an induction motor by other means, e.g., with the aid of firmware.

[0174] Various implementations of the systems and techniques described above can be realized in digital electronic circuitry, integrated circuitry, specially designed application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0175] Computer programs used to implement the methods of the application can be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the computer program, when executed by the processor of the machine, implements the functions / acts specified in the flowcharts and / or block diagrams. The computer program can be executed entirely on a machine, partially on a machine, partially on a machine and partially on a remote machine or entirely on a remote machine or server.

[0176] In the context of the present application, a computer-readable storage medium can be a tangible medium that can contain or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. A computer-readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium can be a machine-readable signal medium. More specific examples of a machine-readable storage medium will include one or more lines of a program of instructions in a transitory signal, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0177] To provide for interaction with a user, the systems and techniques described here can be implemented on an electronic device having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the electronic device. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0178] The systems and techniques described here can be implemented in a computing system that includes a back end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front end component (e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0179] The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system, to solve the defects of large management difficulty and weak business scalability in traditional physical host and VPS service.

[0180] It should be understood that the various forms of flow shown above can be used to reorder, add or delete steps. For example, each step described in the present application can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, which is not limited herein.

[0181] The above detailed description does not constitute a limitation on the scope of protection of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A method of parameter determination of an induction machine, characterized in that, The method comprises the following steps: controlling the excitation current of the motor to be the rated current of the motor when the motor is not connected to a load; determining a target inflection point speed of the motor according to actual currents of the motor at a plurality of different set speeds; wherein a current change rate corresponding to the target inflection point speed is greater than current change rates corresponding to the rest of the set speeds; controlling the target speed of the motor to be the target inflection point speed, controlling the excitation current of the motor to be the rated current, and controlling the motor to operate at the target speed; controlling the excitation current of the motor to gradually increase by a first current step value until the voltage of the motor saturates, and taking the excitation current corresponding to the voltage saturation of the motor as the maximum excitation current of the motor; controlling the target speed of the motor to be the target inflection point speed, controlling the motor to operate at the target speed, and controlling the excitation current of the motor to gradually decrease, and determining the minimum excitation current of the motor according to the excitation current corresponding to the actual current of the motor remaining unchanged.

2. The method of claim 1, wherein, The method comprises the following steps: controlling the speed of the motor to gradually increase from the current minimum set speed to the current maximum set speed by the current step value, and obtaining the actual current of the motor at each set speed; determining the current change rate corresponding to each set speed according to the actual currents corresponding to each two adjacent set speeds, and taking the set speed corresponding to the maximum current change rate as the current inflection point speed; if the current step value is greater than a set threshold, determining the next step value according to the current step value and a step value, determining the next minimum set speed and the next maximum set speed according to the current inflection point speed, and returning to execute the step of controlling the speed of the motor to gradually increase from the current minimum set speed to the current maximum set speed by the current step value, and obtaining the actual current of the motor at each set speed; wherein the next step value is less than the current step value, the current inflection point speed is between the next minimum set speed and the next maximum set speed, the next minimum set speed is greater than the current minimum set speed, and the next maximum set speed is less than the current maximum set speed; if the current step value is less than or equal to the set threshold, taking the current inflection point speed as the target inflection point speed.

3. The method of claim 1, wherein, The method comprises the following steps: controlling the excitation current of the motor to gradually decrease by a second current step value, and taking the sum of the excitation current corresponding to the actual current of the motor remaining unchanged and the second current step value as the minimum excitation current of the motor.

4. The method according to any one of claims 1 to 3, characterized in that, After determining the minimum excitation current of the motor according to the excitation current corresponding to the actual current of the motor remaining unchanged, the method further comprises the following steps: determining the maximum torque current of the motor according to the maximum excitation current and the maximum output current of the voltage circuit connected to the motor.

5. The method of claim 4, wherein, determining a maximum torque current of the motor according to the maximum field current and a maximum output current of a voltage circuit to which the motor is connected, comprises: squaring a difference between the maximum output current and the maximum field current to obtain the maximum torque current.

6. The method of claim 5, wherein, after determining the maximum torque current of the motor according to the maximum field current and the maximum output current of the voltage circuit to which the motor is connected, the method further comprises: after the motor is connected to the load and when the vehicle to which the motor is connected is in the air, gradually increasing a slip value of the motor from a minimum set slip value to a maximum set slip value by a first slip step value, and gradually increasing a rotating speed of the motor from zero to a maximum rotating speed of the motor at a set acceleration at each set slip value; wherein the slip value of the motor is a difference between a rotating speed of a rotor of the motor and a rotating speed of a magnetic field of the motor; determining an initial slip range according to a set slip value corresponding to a time length that the motor gradually increases from zero to the maximum rotating speed and is less than a preset time length; determining a target slip value of the motor according to the initial slip range.

7. The method of claim 6, wherein, determining a target slip value of the motor according to the initial slip range, comprises: gradually increasing the slip value of the motor from a minimum value of the initial slip range to a maximum value of the initial slip range by a second slip step value, and driving the vehicle by the motor under the same preset working condition at each slip value in the initial slip range; obtaining an actual rotating speed of the motor each time the motor drives the vehicle, and taking a slip value corresponding to a maximum value of all actual rotating speeds as the target slip value of the motor.

8. The method of claim 7, wherein, the motor is a traction motor; driving the vehicle by the motor under the same preset working condition, comprises: driving the vehicle by the motor to climb from a first preset position to a second preset position on the same slope; or, the motor is a lifting motor; driving the vehicle by the motor under the same preset working condition, comprises: driving a lifting mechanism of the vehicle by the motor to lift from a third preset position to a fourth preset position under the same load; or, the motor is a traction motor and a lifting motor; driving the vehicle by the motor under the same preset working condition, comprises: driving the vehicle by the motor to climb from a first preset position to a second preset position on the same slope, or driving a lifting mechanism of the vehicle by the motor to lift from a third preset position to a fourth preset position under the same load.

9. A parameter determination device for an induction motor, characterized by comprises: a first motor control module, configured to control a field current of a motor to be a rated current of the motor when the motor is not connected to a load; a target inflection point rotating speed determination module, configured to determine a target inflection point rotating speed of the motor according to actual currents of the motor at a plurality of different set rotating speeds; wherein a current change rate of the motor at the target inflection point rotating speed is greater than current change rates of the motor at other set rotating speeds. The second motor control module is configured to control a target rotating speed of the motor to be the target inflection point rotating speed, control an excitation current of the motor to be the rated current, and control the motor to operate at the target rotating speed. The maximum excitation current determination module is configured to gradually increase the excitation current of the motor according to a first current step value until the voltage of the motor is saturated, and determine the maximum excitation current of the motor as the excitation current corresponding to the voltage saturation of the motor. The minimum excitation current determination module is configured to control the target rotating speed of the motor to be the target inflection point rotating speed, control the motor to operate at the target rotating speed, gradually decrease the excitation current of the motor, and determine the minimum excitation current of the motor according to the excitation current corresponding to the actual current of the motor being maintained unchanged.

10. An electronic device, comprising: The electronic device comprises: at least one processor; and a memory connected with the at least one processor in communication; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to execute the parameter determination method of the induction motor according to any one of claims 1-8.

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