Parameter determination method and device of induction motor and electronic equipment

Abstract

The invention discloses a parameter determination method and device of an induction motor and electronic equipment. The method comprises the following steps: when a motor is not connected with a load, controlling excitation current of the motor to be rated current of the motor; determining a target inflection point rotating speed of the motor according to the actual current of the motor at a plurality of different set rotating speeds; controlling the target rotating speed of the motor to be the target inflection point rotating speed, controlling the exciting current of the motor to be rated current, and controlling the motor to operate according to the target rotating speed; controlling the exciting current of the motor to be gradually increased until the voltage of the motor is saturated, and taking the corresponding exciting current when the voltage of the motor is saturated as the maximum exciting current of the motor; the target rotating speed of the motor is controlled to be the target inflection point rotating speed, the motor is controlled to operate according to the target rotating speed, the exciting current of the motor is controlled to be gradually reduced, and the minimum exciting current of the motor is determined according to the corresponding exciting current when the actual current of the motor is kept unchanged. According to the technical scheme, the accuracy and applicability of parameter determination of the induction motor are improved.

Description

Technical Field

[0001] This invention relates to the field of induction motor technology, and in particular to a method, apparatus, and electronic device for determining the parameters of an induction motor. Background Technology

[0002] With the rapid development of technologies such as battery energy storage, the development of electric vehicles is accelerating. The core power source of electric vehicles is the electric motor. Electric motors include induction motors, which are characterized by simple structure, low cost, and high reliability, and are currently widely used in low-voltage electric vehicles.

[0003] OEMs equip vehicles with different motors based on factors such as vehicle weight, voltage level, and maximum load. Therefore, it's necessary to determine the parameters for each motor. Existing vehicle controllers can only control motors based on parameters for one type, resulting in poor controller applicability. Changing the motor type requires rebuilding the test environment and measuring the motor parameters, further complicating the applicability of the parameter determination method. Furthermore, rebuilding the test environment leads to changes in the test conditions, making it impossible to accurately determine the motor parameters, thus reducing the accuracy of parameter determination. Summary of the Invention

[0004] This invention provides a method, apparatus, and electronic device for determining the parameters of an induction motor, in order to solve the problem of poor applicability and accuracy of the current method for determining motor parameters.

[0005] According to one aspect of the present invention, a method for determining the parameters of an induction motor is provided, the method comprising:

[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] The target inflection point speed of the motor is determined based on the actual current of the motor at multiple different set speeds; wherein the rate of change of current of the motor at the target inflection point speed is greater than the rate of change of current at the other 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 run at the target speed;

[0009] The excitation current of the motor is controlled to gradually increase 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.

[0010] 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 controlled to gradually decrease. The minimum excitation current of the motor is determined based on the excitation current corresponding to the actual current of the motor remaining constant.

[0011] Optionally, the target inflection point speed of the motor is determined based on the actual current of the motor at multiple different set speeds, including:

[0012] The speed of the motor is controlled to gradually increase from the current minimum set speed to the current maximum set speed with the current step size value, and the actual current of the motor at each set speed is obtained;

[0013] Based on the actual current corresponding to every two adjacent set speeds, determine the rate of change of current corresponding to each set speed, and take the set speed corresponding to the maximum rate of change of current as the current inflection point speed.

[0014] If the current step size is greater than a set threshold, then the next step size is determined based on the current step size and the step value. The next minimum set speed and the next maximum set speed are determined based on the current inflection point speed. The process then returns to the step of controlling the motor speed to gradually increase from the current minimum set speed to the current maximum set speed with the current step size, and obtaining the actual current of the motor at each set speed. Wherein, the next step size is less than the current step size, 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.

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

[0016] Optionally, the excitation current of the motor is controlled to gradually decrease, and the minimum excitation current of the motor is determined based on the excitation current corresponding to when the actual current of the motor remains constant, including:

[0017] The excitation current of the motor is controlled to gradually decrease according to the second current step value. The sum of the excitation current corresponding to the actual current of the motor being kept constant and the second current step value is taken as the minimum excitation current of the motor.

[0018] Optionally, after determining the minimum excitation current of the motor based on the excitation current corresponding to the actual current of the motor remaining constant, the method further includes:

[0019] The maximum torque current of the motor is determined based on 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 based on the maximum excitation current and the maximum output current of the voltage circuit connected to the motor includes:

[0021] The maximum torque current is obtained by taking the square root of the difference between the square of the maximum output current and the square of the maximum excitation current.

[0022] Optionally, after determining the maximum torque current of the motor based on the maximum excitation current and the maximum output current of the voltage circuit connected to the motor, the method further includes:

[0023] After the motor is connected to the load, and when the vehicle containing the motor is suspended in the air, the slip value of the motor is controlled to gradually increase from the minimum set slip value to the maximum set slip value with a first slip step value, and at each set slip value, the speed of the motor is controlled to gradually increase from zero to the maximum speed of the motor according to 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;

[0024] The initial slip range is determined based on the set slip value corresponding to the time taken for the motor to gradually increase from zero to the maximum speed being less than a preset time.

[0025] The target slip value of the motor is determined based on the initial slip range.

[0026] Optionally, determining the target slip value of the motor based on the initial slip range includes:

[0027] The motor slip value is controlled to gradually increase from the minimum value of the initial slip range to the maximum value of the initial slip range according to the second slip step value, and the motor is controlled to drive the vehicle under the same preset working condition when the motor is at each slip value in the initial slip range;

[0028] The actual rotational speed of the motor driving the vehicle is obtained each time, and the slip value corresponding to the maximum value among all actual rotational speeds is taken as the target slip value of the motor.

[0029] Optionally, the motor is a traction motor; controlling the motor to drive the vehicle under the same preset operating conditions includes:

[0030] Control the motor to drive the vehicle from a first preset position to a second preset position on the same slope;

[0031] Alternatively, the motor may be a lifting motor; controlling the motor to drive the vehicle under the same preset operating conditions includes:

[0032] Under the same load, the motor is controlled to drive the vehicle's lifting mechanism to lift from the third preset position to the fourth preset position;

[0033] Alternatively, the motor may be a traction and lifting motor; controlling the motor to drive the vehicle under the same preset operating conditions includes:

[0034] The motor is controlled to lift the vehicle from a first preset position to a second preset position on the same slope, or, under the same load, the motor is controlled to lift the vehicle's lifting mechanism from a third preset position to a fourth preset position.

[0035] According to another aspect of the present invention, a parameter determining device for an induction motor is provided, the parameter determining device for an induction motor comprising:

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

[0037] The target inflection point speed determination module is used to determine the target inflection point speed of the motor based on the actual current of the motor at multiple different set speeds; wherein, the rate of change of current of the motor at the target inflection point speed is greater than the rate of change of current at the other set speeds;

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

[0039] The maximum excitation current determination module is used to control the excitation current of the motor to gradually increase according to the first current step value until the voltage of the motor is saturated, and to 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 used to control the target speed of the motor to the target inflection point speed, control the motor to run at the target speed, control the excitation current of the motor to gradually decrease, and determine the minimum excitation current of the motor based on the excitation current corresponding to the actual current of the motor remaining constant.

[0041] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising:

[0042] At least one processor; and

[0043] A memory communicatively connected to the at least one processor; wherein,

[0044] The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to perform the parameter determination method for an induction motor according to any embodiment of the present invention.

[0045] The technical solution of this invention involves controlling the motor's excitation current to its rated current when the motor is not connected to a load. Based on the actual current of the motor at multiple different set speeds, a target inflection point speed is determined. The target speed is then controlled, and the excitation current is set to the rated current. The motor operates at the target speed, and the excitation current gradually increases according to a first current step value until the motor voltage saturates. The excitation current corresponding to voltage saturation is taken as the maximum excitation current. The excitation current is then gradually decreased, and the minimum excitation current is determined based on the excitation current when the actual motor current remains constant. At the target inflection point speed, the motor achieves a large torque value. When the motor speed exceeds the target inflection point speed, the torque decreases, and the excitation current continues to increase, resulting in significant additional power consumption. When the motor speed is below the target inflection point speed, the motor achieves a large torque value, but the excitation current is also smaller due to the lower speed. Therefore, controlling the motor's target speed to be the target inflection point speed allows for the determination of the motor's maximum excitation current without incurring significant additional power consumption. In other words, controlling the motor's target speed to the target inflection point speed enables the determination of a more suitable maximum excitation current, thereby improving the accuracy of motor parameter determination. Furthermore, determining the minimum excitation current of the motor based on the excitation current corresponding to a constant actual motor current avoids situations where the minimum excitation current is too small, failing to maintain the motor's magnetic field. This allows for better determination of induction motor parameters and enables the determination of parameters for different induction motors, improving the applicability of induction motor parameter determination.

[0046] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

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

[0048] Figure 1This is a flowchart of a method for determining the parameters of an induction motor according to an embodiment of the present invention;

[0049] Figure 2 This is a flowchart of another method for determining the parameters of an induction motor provided in an embodiment of the present invention;

[0050] Figure 3 This is a flowchart of another method for determining the parameters of an induction motor provided in an embodiment of the present invention;

[0051] Figure 4 This is a flowchart of another method for determining the parameters of an induction motor provided in an embodiment of the present invention;

[0052] Figure 5 This is a flowchart of another method for determining the parameters of an induction motor provided in an embodiment of the present invention;

[0053] Figure 6 This is a schematic diagram of the structure of a parameter determination device for an induction motor provided in an embodiment of the present invention;

[0054] Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0055] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0056] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0057] This invention provides a method for determining the parameters of an induction motor. The induction motor can be applied to vehicles, including electric vehicles, electric industrial vehicles, and electric forklifts, electric aerial work platforms, and electric loaders. The parameters of the induction motor can include its maximum and minimum excitation current.

[0058] Figure 1 This is a flowchart of a method for determining the parameters of an induction motor according to an embodiment of the present invention. (Refer to...) Figure 1 The methods for determining the parameters of an induction motor include:

[0059] S110. When the motor is not connected to a load, control the excitation current of the motor to be the rated current of the motor.

[0060] The motor is an induction motor. The load can be the gearbox. When the motor is not connected to a load, it is disconnected from the vehicle, placing the motor in an unloaded state. The rated current of the motor is the rated current marked on the motor at the factory; this is the rated line current.

[0061] Specifically, when the motor is not connected to a load, the motor's excitation current is controlled to be the motor's rated current. This allows for the determination of the motor's current variation with its speed when the excitation current is at its rated value, thus avoiding an excessively low or high excitation current and facilitating the accurate determination of the motor's target inflection point speed. If the excitation current is too low, the determined target inflection point speed may be too low; if the excitation current is greater than the rated current, the excitation current will be too large and will affect the motor's operation.

[0062] S120. Determine the target inflection point speed of the motor based on the actual current of the motor at multiple different set speeds; wherein the rate of change of current at the target inflection point speed is greater than the rate of change of current at the other set speeds.

[0063] Specifically, when the motor's excitation current is at its rated current, multiple different set speeds are established. The motor is controlled to run at these set speeds, and the actual current at each set speed is detected. This allows the determination of the rate of change of current at each set speed. For example, the actual current of the motor running at the nth set speed is... The actual current of the motor when it runs at the (n+1)th set speed is If the difference between the (n+1)th set speed and the nth set speed is 'a', then the rate of change of current corresponding to the (n+1)th set speed is 'a'. n is a positive integer. For example, if the difference between any two adjacent set speeds is the same, the rate of change of current corresponding to the first set speed can be the ratio of the actual current at the first set speed to a.

[0064] During motor operation, as the motor speed increases, the torque initially remains constant, followed by constant power. In other words, as the motor speed increases, the torque initially stabilizes, but after reaching a certain value (the inflection point speed), the torque suddenly changes significantly, subsequently decreasing as the motor speed increases further. Therefore, at the target inflection point speed, the actual current of the motor will change significantly. Thus, the target inflection point speed can be determined based on the rate of change of current. For example, the speed corresponding to the maximum value among all the rates of change of current can be taken as the target inflection point speed; that is, the rate of change of current at the target inflection point speed is greater than the rate of change of current at the other set speeds.

[0065] S130: Control the target speed of the motor to the target inflection point speed, control the excitation current of the motor to the rated current, and control the motor to run at the target speed.

[0066] Specifically, at the target inflection point speed, the motor achieves a large torque value. When the motor speed exceeds the target inflection point speed, the torque decreases, and the excitation current continues to increase, resulting in significant additional power consumption. When the motor speed is below the target inflection point speed, it still achieves a large torque value, but the lower speed results in a lower excitation current. Therefore, controlling the motor's target speed to be the target inflection point speed, ensuring the motor operates at that speed, allows for the determination of the maximum excitation current without incurring significant additional power consumption. In other words, controlling the motor's target speed to be the target inflection point speed determines a more suitable maximum excitation current. Controlling the motor to operate at the target speed means controlling the motor's actual speed to follow the target speed, ensuring the motor reaches the target inflection point speed. Controlling the motor's excitation current to be the rated current ensures the motor voltage is at the rated voltage.

[0067] It should be noted that if the motor voltage does not reach the rated voltage when the motor excitation current is the rated current, the excitation current can be adjusted to make the motor voltage reach the rated voltage. In the subsequent process, the motor excitation current is controlled to increase according to the adjusted excitation current.

[0068] S140. Control the excitation current of the motor to gradually increase according to the first current step value until the motor voltage is saturated, and take the excitation current corresponding to the motor voltage saturation 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 voltage between any two phases of the motor is obtained. The excitation current corresponding to the point where the motor reaches voltage saturation (i.e., the voltage does not increase further when the excitation current is increased) 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 vehicle's controller. This allows the vehicle's controller to keep the motor's excitation current below the maximum excitation current during operation, preventing excessive excitation current and thus avoiding excessive power consumption. This results in better control of the motor's operation and consequently, better control of the vehicle's operation.

[0071] S150. Control the target speed of the motor to the target inflection point speed, and control the motor to run at the target speed. Control the excitation current of the motor to gradually decrease. Determine the minimum excitation current of the motor based on the excitation current corresponding to the motor when the actual current of the motor remains constant.

[0072] Specifically, the target speed of the motor is still controlled as the target inflection point speed, and the motor is controlled to run at the target speed. Since the excitation current of the motor was adjusted too high in step S140, the excitation current of the motor is gradually reduced. As the excitation current of the motor gradually decreases, the actual current of the motor gradually decreases until the actual current of the motor remains constant. If the excitation current is further reduced, the magnetic field of the motor cannot be maintained. Therefore, the minimum excitation current of the motor can be determined based on the excitation current corresponding to when the actual current of the motor remains constant.

[0073] By determining the minimum excitation current of the motor, this minimum excitation current can be transmitted to the vehicle's controller. This ensures that during motor operation, the vehicle's controller maintains a motor excitation current greater than the minimum excitation current, guaranteeing normal motor operation and ensuring that the actual motor speed reaches the target inflection point speed. This means that the motor torque can be relatively large, thereby achieving better control of motor operation and, consequently, better control of the vehicle's operation.

[0074] The technical solution of this embodiment involves controlling the motor's excitation current to its rated current when the motor is not connected to a load. Based on the actual current of the motor at multiple different set speeds, a target inflection point speed is determined. The target speed is then controlled, and the excitation current is set to the rated current. The motor operates at the target speed, and the excitation current gradually increases according to a first current step value until the motor voltage saturates. The excitation current corresponding to voltage saturation is taken as the maximum excitation current. The excitation current is then gradually decreased, and the minimum excitation current is determined based on the excitation current when the actual motor current remains constant. At the target inflection point speed, the motor achieves a large torque value. When the motor speed exceeds the target inflection point speed, the torque decreases, and the excitation current continues to increase, resulting in significant additional power consumption. When the motor speed is below the target inflection point speed, the motor achieves a large torque value, but the excitation current is also smaller due to the lower speed. Therefore, controlling the motor's target speed to be the target inflection point speed allows for the determination of the motor's maximum excitation current without incurring significant additional power consumption. In other words, controlling the motor's target speed to the target inflection point speed enables the determination of a more suitable maximum excitation current, thereby improving the accuracy of motor parameter determination. Furthermore, determining the minimum excitation current of the motor based on the excitation current corresponding to a constant actual motor current avoids situations where the minimum excitation current is too small, failing to maintain the motor's magnetic field. This allows for better determination of induction motor parameters and enables the determination of parameters for different induction motors, improving the applicability of induction motor parameter determination.

[0075] Based on the above technical solutions, Figure 2 This is a flowchart of another method for determining the parameters of an induction motor provided in an embodiment of the present invention. Optionally, refer to... Figure 2 The methods for determining the parameters of an induction motor include:

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

[0077] S220: Control the motor speed to gradually increase from the current minimum set speed to the current maximum set speed with the current step size value, and obtain the actual current of the motor at each set speed.

[0078] Specifically, the current step size is the step size by which the set speed increases. The motor speed is controlled to gradually increase from the current minimum set speed to the current maximum set speed with the current step size, so that the motor can run at multiple set speeds and the actual current of the motor at each set speed can be obtained.

[0079] For example, when controlling the motor speed to gradually increase from the current minimum set speed to the current maximum set speed for the first time, the current step size is 200 rpm, the current minimum set speed is 200 rpm, the current maximum set speed is the maximum speed that the motor can reach, Vmax (the maximum speed marked when the motor leaves the factory), and the actual current of the motor when it runs at each set speed is obtained. Table 1 is a schematic diagram showing the correspondence between the motor speed and the actual current of the motor according to an embodiment of the present invention. As shown in Table 1, when the motor speed is set at 200 rpm, the actual current of the motor is A11; when the motor speed is set at 400 rpm, the actual current of the motor is A12; when the motor speed is set at 600 rpm, the actual current of the motor is A13; when the motor speed is set at 800 rpm, the actual current of the motor is A14; when the motor speed is set at 1000 rpm, the actual current of the motor is A15; when the motor speed is set at 1200 rpm, the actual current of the motor is A16; when the motor speed is set at 1400 rpm, the actual current of the motor is A17... When the motor speed is set at Vmax, the actual current of the motor is Am.

[0080] Table 1. A schematic diagram showing the correspondence between the motor speed and the actual current of the motor according to an embodiment of the present invention.

[0081]

[0082] For example, when controlling the motor speed to gradually increase from the current minimum set speed to the current maximum set speed for the second time, the current step size is 50 rpm, the current minimum set speed is 800 rpm, and the current maximum set speed is 1400 rpm, and the actual current of the motor at each set speed is obtained. Table 2 is a schematic diagram showing the correspondence between the motor speed and the actual current of the motor according to another embodiment of the present invention. As shown in Table 2, when the motor speed is 800 rpm, the actual current of the motor is A21; when the motor speed is 850 rpm, the actual current of the motor is A22; when the motor speed is 900 rpm, the actual current of the motor is A23; when the motor speed is 950 rpm, the actual current of the motor is A24; when the motor speed is 1000 rpm, the actual current of the motor is A25; when the motor speed is 1050 rpm, the actual current of the motor is A26; when the motor speed is 1100 rpm, the actual current of the motor is A27... and when the motor speed is 1400 rpm, the actual current of the motor is Ax.

[0083] Table 2. Schematic diagram of the correspondence between the rotational speed and actual current of another motor provided in the embodiments of the present invention.

[0084]

[0085] S230. Based on the actual current corresponding to every two adjacent set speeds, determine the current change rate corresponding to each set speed, and take the set speed corresponding to the maximum current change rate as the current inflection point speed.

[0086] Specifically, the difference between two adjacent set speeds is the current step size. The current change rate corresponding to a set speed can be obtained by subtracting the difference between the actual current at the previous set speed and the actual current at the current set speed, and then dividing by the current step size. The current change rate at the first set speed can be the ratio of the actual current at that first set speed to the current step size. In this way, the current change rate for each set speed can be determined, and the set speed corresponding to the maximum value of all current change rates 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, based on the actual motor current shown in Table 1, determine the current change rate corresponding to each set speed. If the set speed corresponding to the maximum current change rate is determined to be 1200 rpm, then the current inflection point speed is 1200 rpm. For example, based on the actual motor current shown in Table 2, determine the current change rate corresponding to each set speed. If the set speed corresponding to the maximum current change rate is determined to be 1100 rpm, then the current inflection point speed is 1100 rpm.

[0088] S240. Determine whether the current step size is greater than the set threshold. If yes, proceed to step S250; otherwise, proceed to step S260.

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

[0090] S250. Determine the next step length value based on the current step length value and step value, determine the next minimum set speed and the next maximum set speed based on the current inflection point speed, and return to execute step S220; wherein, the next step length value is less than the current step length 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 size is greater than a set threshold, the next step size is determined based on the current step size and the step value. That is, the current step size is subtracted from the step value to obtain the next step size, which is made to be less than the current step size. It can be seen that the next step size is the current step size in the next execution of step S220.

[0092] The next minimum set speed and the next maximum set speed are determined based on the current inflection point speed. The current inflection point speed falls between these two speeds, with the next minimum set speed being greater than the current minimum set speed and the next maximum set speed being less than the current maximum set speed. In other words, the range of set speeds for the next execution of step S220 is smaller than the range of set speeds for the current execution of step S220, and the range of set speeds for the next execution of step S220 includes the current inflection point speed. This narrows the range of set speeds, resulting in a smaller error between the determined target inflection point speed and the actual inflection point speed, facilitating the determination of a more accurate target inflection point speed. Furthermore, when the current step size is less than or equal to a set threshold, the error in the determined target inflection point speed is less than the set threshold, thereby improving the accuracy of the target inflection point speed determination.

[0093] For example, if the next step value determined based on the current step size and step increment is 50 rpm, and the current inflection point speed is 1200 rpm, the next minimum set speed is determined to be 800 rpm, and the next maximum set speed is determined to be 1400 rpm. Continuing to return to step S220, the correspondence between the motor speed and the actual motor current shown in Table 2 can be obtained, i.e., the actual current corresponding to each set speed is determined.

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

[0095] Specifically, when the current step size is less than or equal to a set threshold, the current inflection point speed is taken as the target inflection point speed. This ensures that the error in the determined target inflection point speed is less than the set threshold, and the difference between the determined target inflection point speed and the actual inflection point speed is small, thus improving the accuracy of the target inflection point speed determination. This facilitates the determination of more accurate maximum and minimum excitation currents based on the target inflection point speed, which is beneficial for improving the accuracy of parameter determination for the induction motor. For example, if the set threshold is 50 rpm, and the current step size is 50 rpm, the set speed corresponding to the maximum current change rate is determined to be 1100 rpm, meaning the determined current inflection point speed is 1100 rpm, and therefore the target inflection point speed is 1100 rpm.

[0096] S270: Control the target speed of the motor to the target inflection point speed, control the excitation current of the motor to the rated current, and control the motor to run at the target speed.

[0097] S280. Control the excitation current of the motor to gradually increase according to the first current step value until the motor voltage is saturated, and take the excitation current corresponding to the motor voltage saturation as the maximum excitation current of the motor.

[0098] S290. Control the target speed of the motor to the target inflection point speed, and control the motor to run at the target speed. Control the excitation current of the motor to gradually decrease. Determine the minimum excitation current of the motor based on the excitation current corresponding to the motor when the actual current of the motor remains constant.

[0099] Based on the above technical solutions, 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 remaining constant, including:

[0100] The excitation current of the motor is gradually reduced according to the second current step value. The sum of the excitation current corresponding to keeping the actual current of the motor constant 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 decreased according to the second current step value until, after a certain reduction in the excitation current, the actual current of the motor no longer changes. If the excitation current is further reduced, the motor enters an under-excitation state, resulting in a significant increase in the motor's torque current (because a larger torque current is needed to compensate for the torque decrease caused by insufficient magnetic flux). This further increases the actual current of the motor. In other words, if the excitation current is further reduced after the actual current remains constant, the excitation current will become too small. Therefore, the previous excitation current corresponding to the point where the actual current remains constant is taken as the minimum excitation current of the motor. That is, under the previous excitation current corresponding to the point where the actual current remains constant, the actual current of the motor can still change according to the change in the excitation current. The previous excitation current corresponding to the point where the actual current remains constant is the minimum excitation current that ensures the normal operation of the motor. The previous excitation current corresponding to the point where the actual current remains constant is the sum of the excitation current corresponding to the point where the actual current remains constant and the second current step value.

[0102] Based on the above technical solutions, Figure 3 This is a flowchart of another method for determining the parameters of an induction motor provided in an embodiment of the present invention. Optionally, refer to... Figure 3 The methods for determining the parameters of an induction motor include:

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

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

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

[0106] S340. Determine whether the current step size is greater than the set threshold. If yes, proceed to step S350; otherwise, proceed to step S360.

[0107] S350. Determine the next step length value based on the current step length value and step value, determine the next minimum set speed and the next maximum set speed based on the current inflection point speed, and return to execute step S320; wherein, the next step length value is less than the current step length 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.

[0108] S360, Take the current inflection point speed as the target inflection point speed; wherein, the rate of change of current of the motor at the target inflection point speed is greater than the rate of change of current at other set speeds.

[0109] S370: Control the target speed of the motor to the target inflection point speed, control the excitation current of the motor to the rated current, and control the motor to run at the target speed.

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

[0111] S390. Control the target speed of the motor to the target inflection point speed, and control the motor to run at the target speed. Control the excitation current of the motor to gradually decrease according to the second current step value. The sum of the excitation current corresponding to the motor's actual current and the second current step value is taken as the minimum excitation current of the motor.

[0112] S391. Determine the maximum torque current of the motor based on the maximum excitation current and the maximum output current of the voltage circuit connected to the motor.

[0113] Specifically, the motor is connected to a voltage circuit, which can be an inverter circuit to convert direct current into three-phase alternating current to power 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, based on the relationship between the coordinate systems, the maximum excitation current and the maximum output current of the voltage circuit connected to the motor can be used to determine the maximum torque current of the motor.

[0114] In this way, the determined maximum torque current can be transmitted to the vehicle's controller, so that when the motor is running, the vehicle's controller will control the motor's torque current to be less than the motor's maximum torque current, thus avoiding excessive torque current.

[0115] Based on the above technical solution, optionally, 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, including:

[0116] The maximum torque current is obtained by taking the square root of the difference between the square of the maximum output current and the square of the maximum excitation current.

[0117] For example, the maximum output current is The maximum excitation current is The maximum torque current is ,but ,but Therefore, the maximum torque current of the motor can be determined based on the maximum excitation current and the maximum output current of the voltage circuit connected to the motor.

[0118] Based on the above technical solutions, Figure 4 This is a flowchart of another method for determining the parameters of an induction motor provided in an embodiment of the present invention. Optionally, refer to... Figure 4 The methods for determining the parameters of an induction motor include:

[0119] S410. When the motor is not connected to a load, control the excitation current of the motor to be the rated current of the motor.

[0120] S420: Control the motor speed to gradually increase from the current minimum set speed to the current maximum set speed with the current step size value, and obtain the actual current of the motor at each set speed.

[0121] S430. Based on the actual current corresponding to every two adjacent set speeds, determine the current change rate corresponding to each set speed, and take the set speed corresponding to the maximum current change rate as the current inflection point speed.

[0122] S440. Determine whether the current step size is greater than the set threshold. If yes, proceed to step S450; otherwise, proceed to step S460.

[0123] S450. Determine the next step length value based on the current step length value and step value, determine the next minimum set speed and the next maximum set speed based on the current inflection point speed, and return to execute step S420; wherein, the next step length value is less than the current step length 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 the target inflection point speed; wherein, the rate of change of current of the motor at the target inflection point speed is greater than the rate of change of current at other set speeds.

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

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

[0127] S490. Control the target speed of the motor to the target inflection point speed, and control the motor to run at the target speed. Control the excitation current of the motor to gradually decrease according to the second current step value. The sum of the excitation current corresponding to the motor's actual current and the second current step value is taken as the minimum excitation current of the motor.

[0128] S491. Determine the maximum torque current of the motor based on 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 containing the motor is suspended in the air, the slip value of the motor is controlled to gradually increase from the minimum set slip value to the maximum set slip value with a first slip step value, and at each set slip value, the speed of the motor is controlled to gradually increase from zero to the maximum speed of the motor according to the 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 acceleration is set to the maximum acceleration that the motor can achieve, which is the maximum acceleration marked at the factory. The maximum speed of the motor is the maximum speed marked at the factory.

[0131] Specifically, after connecting the motor to the load (e.g., the gearbox), the motor is connected to the vehicle, but the vehicle is suspended in the air, meaning it does not move forward or backward. The motor's slip value is controlled to gradually increase from the minimum set slip value to the maximum set slip value in a first slip step value, so that the motor is at multiple different set slip values, and the motor slip value gradually increases. At each set slip value, the motor speed is controlled to gradually increase from zero to the motor's maximum speed according to a set acceleration.

[0132] S493. Determine the initial slip range based on the set slip value corresponding to the time taken for the motor to gradually increase from zero to the maximum speed being less than the preset time.

[0133] Specifically, the set slip value that meets the requirements is the time taken for the motor to gradually increase from zero to its maximum speed, which is less than a preset time. There are multiple consecutive set slip values ​​that meet the requirements. The slip range formed by these consecutive set slip values ​​is used as the initial slip range. Therefore, when the motor's slip value is within the initial slip range, the motor accelerates faster. For example, if the first slip step value is d0, and all the set slip values ​​are d1, d1+d0, d1+2d0, d1+3d0, d1+4d0, d1+5d0, d1+6d0, and d1+7d0, when the motor slip value is d1+2d0, d1+5d0, d1+6d0, and d1+7d0, the time taken for the motor to gradually increase from zero to the maximum speed is less than the preset time. That is, when all the set slip values ​​that meet the requirements are d1+2d0, d1+5d0, d1+6d0, and d1+7d0, and multiple consecutive set slip values ​​among all the set slip values ​​that meet the requirements are d1+5d0, d1+6d0, and d1+7d0, then the initial slip range is formed from d1+5d0 to d1+7d0, thus determining the initial slip range.

[0134] S494. Determine the target slip value of the motor based on the initial slip range.

[0135] Specifically, when the motor's slip value is within the initial slip range, the motor accelerates relatively quickly. Therefore, any slip value within the initial slip range can be used as the target slip value for the motor. Alternatively, the slip value within the initial slip range corresponding to a higher motor operating efficiency can be used as the target slip value. This ensures that the determined target slip value guarantees both rapid acceleration and high efficiency during actual motor operation.

[0136] Based on the above technical solutions, Figure 5 This is a flowchart of another method for determining the parameters of an induction motor provided in an embodiment of the present invention. Optionally, refer to... Figure 5 The methods for determining the parameters of an induction motor include:

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

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

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

[0140] S540. Determine whether the current step size is greater than the set threshold. If yes, proceed to step S550; otherwise, proceed to step S560.

[0141] S550. Determine the next step length value based on the current step length value and step value, determine the next minimum set speed and the next maximum set speed based on the current inflection point speed, and return to execute step S520; wherein, the next step length value is less than the current step length 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.

[0142] S560, Take the current inflection point speed as the target inflection point speed; wherein, the rate of change of current of the motor at the target inflection point speed is greater than the rate of change of current at other set speeds.

[0143] S570: Control the target speed of the motor to the target inflection point speed, control the excitation current of the motor to the rated current, and control the motor to run at the target speed.

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

[0145] S590. Control the target speed of the motor to the target inflection point speed, and control the motor to run at the target speed. Control the excitation current of the motor to gradually decrease according to the second current step value. The sum of the excitation current corresponding to the motor's actual current and the second current step value is taken as the minimum excitation current of the motor.

[0146] S591. Determine the maximum torque current of the motor based on the maximum excitation current and the maximum output current of the voltage circuit connected to the motor.

[0147] S592. After the motor is connected to the load, and when the vehicle containing the motor is suspended in the air, the slip value of the motor is controlled to gradually increase from the minimum set slip value to the maximum set slip value with a first slip step value, and at each set slip value, the speed of the motor is controlled to gradually increase from zero to the maximum speed of the motor according to the set acceleration; wherein, the slip value of the motor is the difference between the rotor speed and the magnetic field speed of the motor.

[0148] S593. Determine the initial slip range based on the set slip value corresponding to the time taken for the motor to gradually increase from zero to the maximum speed being less than the preset time.

[0149] S594. The control motor slip value is gradually increased from the minimum value of the initial slip range to the maximum value of the initial slip range according to the second slip step value, and the control motor drives the vehicle to run under the same preset working condition at each slip value in the initial slip range.

[0150] Specifically, the slip value of the control motor is gradually increased from the minimum to the maximum value of the initial slip range according to a second slip step value. For example, the second slip step value is b, the minimum value of the initial slip range is c1, and the maximum value of the initial slip range is c2. The slip values ​​of the control motor are c1, c1+b, c1+2b, ..., c2, respectively. When the motor is at each slip value within the initial slip range, the control motor drives the vehicle under the same preset operating conditions. For example, the control motor drives the vehicle up a slope, or drives the vehicle on flat ground, or drives the vehicle's lifting mechanism to lift under the same load, etc., without limitation. In this way, the target slip value of the motor can be determined according to the actual operating conditions of the motor in practical applications, making the determined target slip value more accurate and further improving the accuracy of the induction motor parameter determination.

[0151] S595. Obtain the actual speed of the motor each time it drives the vehicle, and take the slip value corresponding to the maximum value among all actual speeds as the target slip value of the motor.

[0152] Specifically, for each slip value within the initial slip range, the control motor drives the vehicle under the same preset operating conditions, and the actual speed of the motor at each slip value within the initial slip range is obtained. The slip value corresponding to the maximum value among all actual speeds is taken as the target slip value of the motor. In this way, the determined target slip value ensures that the actual operating speed of the motor is relatively high, thereby improving the operating efficiency of the motor.

[0153] Based on the above technical solution, optionally, the motor is a traction motor; controlling the motor to drive the vehicle under the same preset operating conditions includes:

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

[0155] Alternatively, the motor may be a lifting motor; controlling the motor to drive the vehicle under the same preset operating conditions includes:

[0156] Under the same load, the control motor drives the vehicle's lifting mechanism to lift from the third preset position to the fourth preset position;

[0157] Alternatively, the motor can be a traction and lifting motor; controlling the motor to drive the vehicle under the same preset operating conditions includes:

[0158] The control motor drives the vehicle to climb from the first preset position to the second preset position on the same slope, or, under the same load, the control motor drives the vehicle's lifting mechanism to lift from the third preset position to the fourth preset position.

[0159] Specifically, if the motor is a traction motor, i.e., a motor that drives the vehicle forward, backward, and turning, then the motor can be controlled to drive the vehicle up a slope from a first preset position to a second preset position. That is, at each slip value within the initial slip range, the motor is controlled to drive the vehicle up the slope from the first preset position to the second preset position, achieving motor operation control under the same working conditions. At each slip value within the initial slip range, the actual stable operating speed of the motor when driving the vehicle up the slope from the first preset position to the second preset position is obtained. The slip value corresponding to the maximum value among all actual speeds is used as the target slip value for the motor, resulting in higher motor operating efficiency. 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 and second preset positions can also be other positions, without limitation.

[0160] If the motor is a lifting motor, i.e., the motor that drives the vehicle's lifting mechanism, then under the same load (i.e., the same load on the vehicle), the motor can be controlled to lift the vehicle's lifting mechanism from the third preset position to the fourth preset position. That is, at each slip value within the initial slip range, the motor is controlled to lift the vehicle's lifting mechanism from the third preset position to the fourth preset position with the same load. At each slip value within the initial slip range, the actual rotational speed of the motor during stable operation when lifting the vehicle's lifting mechanism from the third preset position to the fourth preset position under the same load is obtained. The slip value corresponding to the maximum value of all actual rotational speeds is used as the target slip value for the motor, resulting in higher motor operating efficiency. 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 mechanism rising to a preset height. The third and fourth preset positions can also be other positions, which are not limited here.

[0161] If the motor has both traction and lifting functions, it can be arbitrarily selected to control the motor to traction the vehicle or to control the motor to lift the vehicle. That is, the motor can be controlled to lift the vehicle from the first preset position to the second preset position on the same slope, or, under the same load, the motor can be controlled to lift the vehicle from the third preset position to the fourth preset position. No limitation is imposed here.

[0162] This invention also provides a parameter determination device for an induction motor. Figure 6 This is a schematic diagram of the structure of a parameter determination device for an induction motor provided in an embodiment of the present invention. (Refer to...) Figure 6 The parameter determination device for the induction motor includes:

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

[0164] The target inflection point speed determination module 102 is used to determine the target inflection point speed of the motor based on the actual current of the motor at multiple different set speeds; wherein, the rate of change of current of the motor at the target inflection point speed is greater than the rate of change of current at the other set speeds.

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

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

[0167] The minimum excitation current determination module 105 is used to control the target speed of the motor to the target inflection point speed and control the motor to run at the target speed. It controls the excitation current of the motor to gradually decrease and determines the minimum excitation current of the motor based on the excitation current corresponding to the actual current of the motor remaining constant.

[0168] The parameter determination device for an induction motor provided in this embodiment of the invention can execute the parameter determination method for an induction motor provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the method.

[0169] This invention also provides an electronic device. Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Figure 7A schematic diagram of an electronic device 10, which can be used to implement embodiments of the present invention, is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

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

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

[0172] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of 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 suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the parameter determination method for an induction motor.

[0173] In some embodiments, the induction motor parameter determination method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the induction motor parameter determination method described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the induction motor parameter determination method by any other suitable means (e.g., by means of firmware).

[0174] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0175] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0176] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0177] To provide interaction with a user, the systems and techniques described herein 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 pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; 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 sound input, voice input, or tactile input).

[0178] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or middleware components (e.g., application servers), or frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0179] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0180] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0181] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. 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 substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for determining the parameters of an induction motor, characterized in that, include: 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. The target inflection point speed of the motor is determined based on the actual current of the motor at multiple different set speeds; wherein the rate of change of current of the motor at the target inflection point speed is greater than the rate of change of current at the other 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 run at the target speed; The excitation current of the motor is controlled to gradually increase 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. 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 controlled to gradually decrease. The minimum excitation current of the motor is determined based on the excitation current corresponding to the actual current of the motor remaining constant.

2. The method according to claim 1, characterized in that, Determining the target inflection point speed of the motor based on the actual current of the motor at multiple different set speeds includes: The speed of the motor is controlled to gradually increase from the current minimum set speed to the current maximum set speed with the current step size value, and the actual current of the motor at each set speed is obtained; Based on the actual current corresponding to every two adjacent set speeds, determine the rate of change of current corresponding to each set speed, and take the set speed corresponding to the maximum rate of change of current as the current inflection point speed. If the current step size is greater than a set threshold, then the next step size is determined based on the current step size and the step value. The next minimum set speed and the next maximum set speed are determined based on the current inflection point speed. The process then returns to the step of controlling the motor speed to gradually increase from the current minimum set speed to the current maximum set speed with the current step size, and obtaining the actual current of the motor at each set speed. Wherein, the next step size is less than the current step size, 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 size is less than or equal to the set threshold, then the current inflection point speed is taken as the target inflection point speed.

3. The method according to claim 1, characterized in that, The excitation current of the motor is gradually reduced. Based on the excitation current corresponding to a constant actual current in the motor, the minimum excitation current of the motor is determined, including: The excitation current of the motor is controlled to gradually decrease according to the second current step value. The sum of the excitation current corresponding to the actual current of the motor being kept constant and the second current step value is taken as the minimum excitation current of the motor.

4. The method according to any one of claims 1-3, characterized in that, After determining the minimum excitation current of the motor based on the excitation current corresponding to the motor's actual current remaining constant, the method further includes: The maximum torque current of the motor is determined based on the maximum excitation current and the maximum output current of the voltage circuit connected to the motor.

5. The method according to claim 4, characterized in that, The maximum torque current of the motor is determined based on the maximum excitation current and the maximum output current of the voltage circuit connected to the motor, including: The maximum torque current is obtained by taking the square root of the difference between the square of the maximum output current and the square of the maximum excitation current.

6. The method according to claim 5, characterized in that, After determining the maximum torque current of the motor based on the maximum excitation current and the maximum output current of the voltage circuit connected to the motor, the method further includes: After the motor is connected to the load, and when the vehicle containing the motor is suspended in the air, the slip value of the motor is controlled to gradually increase from the minimum set slip value to the maximum set slip value with a first slip step value, and at each set slip value, the speed of the motor is controlled to gradually increase from zero to the maximum speed of the motor according to 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; The initial slip range is determined based on the set slip value corresponding to the time taken for the motor to gradually increase from zero to the maximum speed being less than a preset time. The target slip value of the motor is determined based on the initial slip range.

7. The method according to claim 6, characterized in that, Determining the target slip value of the motor based on the initial slip range includes: The motor slip value is controlled to gradually increase from the minimum value of the initial slip range to the maximum value of the initial slip range according to the second slip step value, and the motor is controlled to drive the vehicle under the same preset working condition when the motor is at each slip value in the initial slip range; The actual rotational speed of the motor driving the vehicle is obtained each time, and the slip value corresponding to the maximum value among all actual rotational speeds is taken as the target slip value of the motor.

8. The method according to claim 7, characterized in that, The motor is a traction motor; controlling the motor to drive the vehicle under the same preset operating conditions includes: Control the motor to drive the vehicle from a first preset position to a second preset position on the same slope; Alternatively, the motor may be a lifting motor; controlling the motor to drive the vehicle under the same preset operating conditions includes: Under the same load, the motor is controlled to drive the vehicle's lifting mechanism to lift from the third preset position to the fourth preset position; Alternatively, the motor may be a traction and lifting motor; controlling the motor to drive the vehicle under the same preset operating conditions includes: The motor is controlled to lift the vehicle from a first preset position to a second preset position on the same slope, or, under the same load, the motor is controlled to lift the vehicle's lifting mechanism from a third preset position to a fourth preset position.

9. A parameter determining device for an induction motor, characterized in that, include: The first motor control module is used to control the excitation current of the motor to the rated current of the motor when the motor is not connected to a load. The target inflection point speed determination module is used to determine the target inflection point speed of the motor based on the actual current of the motor at multiple different set speeds; wherein, the rate of change of current of the motor at the target inflection point speed is greater than the rate of change of current at the other set speeds; The second motor control module is used to control the target speed of the motor to the target inflection point speed, control the excitation current of the motor to the rated current, and control the motor to run at the target speed; The maximum excitation current determination module is used to control the excitation current of the motor to gradually increase according to the first current step value until the voltage of the motor is saturated, and to take the excitation current corresponding to the voltage saturation of the motor as the maximum excitation current of the motor. The minimum excitation current determination module is used to control the target speed of the motor to the target inflection point speed, control the motor to run at the target speed, control the excitation current of the motor to gradually decrease, and determine the minimum excitation current of the motor based on the excitation current corresponding to the actual current of the motor remaining constant.

10. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the parameter determination method for the induction motor according to any one of claims 1-8.

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