MTPA control method of permanent magnet synchronous motor and related device

Abstract

The invention discloses an MTPA control method of a permanent magnet synchronous motor and a related device, and belongs to the technical field of motor control, and the method comprises the steps: building a current angle target function of a to-be-controlled motor based on the electromagnetic torque and stator current of the to-be-controlled motor; performing polynomial fitting on the current angle target function of the to-be-controlled motor to obtain polynomial description of the current angle target function; performing dominant description on polynomial description of a current angle objective function according to a Colmogolov-Arnod network, obtaining and solving an interpretable objective function, and obtaining an optimal current angle of the to-be-controlled motor; inputting the optimal current angle of the to-be-controlled motor into an MTPA control module of the to-be-controlled motor, and performing MTPA control on the to-be-controlled motor; according to the method, the optimal current angle of the to-be-controlled motor is accurately calculated, the direct-axis current and the quadrature-axis current of the to-be-controlled motor can be optimally distributed, and the dynamic performance of the permanent magnet synchronous motor is accurately controlled.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor control, and particularly relates to an MTPA control method and related device for a permanent magnet synchronous motor. Background Art

[0002] A permanent magnet synchronous motor (PMSM) is a synchronous motor that uses permanent magnets to generate a magnetic field and plays a crucial role in the electrical field; especially in the field of electric aviation, due to its low energy consumption, fast-response acceleration performance, and extended flight endurance, the PMSM has become the preferred motor type for electric aircraft; according to the different positions of the permanent magnet materials on the motor rotor, the permanent magnet synchronous motor can be divided into an inner-mounted permanent magnet synchronous motor (IPMSM) and a surface-mounted permanent magnet synchronous motor (SPMSM); compared with the SPMSM, the IPMSM has higher torque and power density as well as a wider speed regulation range, making it more advantageous in the field of electric aircraft.

[0003] Currently, the control of permanent magnet synchronous motors generally includes a zero direct-axis control strategy and a maximum torque per ampere (MTPA) control strategy; since the electromagnetic torque in a permanent magnet synchronous motor is mainly related to the direct-axis (d-axis) current, while the reluctance torque is related to both the d-axis current and the quadrature-axis (q-axis) current; therefore, the zero direct-axis control strategy will cause the reluctance torque to drop to zero, thereby reducing the output torque.

[0004] In contrast, the MTPA control strategy optimizes the distribution of the d-axis current and the q-axis current to make the motor output the maximum electromagnetic torque under the condition of a fixed stator current amplitude; therefore, as an efficient control technology, the MTPA control strategy is widely used in the field of electric aviation to ensure the minimization of copper loss during the operation of the permanent magnet synchronous motor, thereby improving the overall operation efficiency and flight stability, and bringing excellent performance and efficiency to the drive system of electric aircraft.

[0005] In the MTPA control strategy, its goal is to find the optimal current angle under the given stator current to maximize the output torque of the motor. Among them, this optimal current angle is called the MTPA angle. Since during the actual operation of the permanent magnet synchronous motor, the operating point of the MTPA angle will change with factors such as temperature, magnetic saturation, and external disturbances. In view of this, in the existing technology, methods based on parameters and methods based on search are generally used to obtain the MTPA angle. However, the above methods rely heavily on complex mathematical models and signal injection techniques, and there are problems such as low computational efficiency, poor interpretability, and difficulty in expansion. Specifically, the method based on parameters is directly calculated by equations and formulas, which highly depends on the availability of accurate parameters and is extremely vulnerable to the specific operating conditions and environmental factors of electric aircraft. The method based on search relies on iterative optimization calculations or obtains it by injecting virtual high-frequency signals, with a relatively low calculation speed and requiring a large amount of computing resources. Summary of the Invention

[0006] Aiming at the technical problems existing in the prior art, the present invention provides an MTPA control method and related device for a permanent magnet synchronous motor to solve the technical problems that the methods for obtaining the MTPA angle in the prior art rely heavily on complex mathematical models and signal injection techniques, and have problems such as low computational efficiency, poor interpretability, and difficulty in expansion.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows: The present invention provides an MTPA control method for a permanent magnet synchronous motor, including: Obtain the electromagnetic torque and stator current of the motor to be controlled; Taking the maximization of the ratio of the electromagnetic torque and stator current of the motor to be controlled as the goal, establish the current angle objective function of the motor to be controlled; Based on Taylor expansion, perform polynomial fitting on the current angle objective function of the motor to be controlled to obtain the polynomial description of the current angle objective function; According to the Kolmogorov - Arnold network, perform an explicit description on the polynomial description of the current angle objective function to obtain an interpretable objective function; Solve the interpretable objective function to obtain the optimal current angle of the motor to be controlled; Based on the optimal current angle of the motor to be controlled, perform MTPA control on the motor to be controlled.

[0008] Further, the process of obtaining the electromagnetic torque and stator current of the motor to be controlled includes: According to the nonlinear equation of the motor to be controlled, establish the MTPA control logic rule of the motor to be controlled; According to the MTPA control logic rule of the motor to be controlled, based on the preset current angle test value, obtain the electromagnetic torque and stator current of the motor to be controlled.

[0009] Furthermore, the non-linear equations of the motor to be controlled include the steady-state voltage equation and the torque equation of the motor to be controlled; The steady-state voltage equation of the motor to be controlled is as follows:

[0010]

[0011]

[0012]

[0013] Wherein, is the equivalent voltage of the motor to be controlled on the direct axis; is the stator resistance of the motor to be controlled; is the equivalent current of the motor to be controlled on the direct axis; is the equivalent inductance of the motor to be controlled on the direct axis; is the equivalent current of the motor to be controlled on the quadrature axis; is time; is the number of pole pairs of the motor to be controlled; is the mechanical rotor speed of the motor to be controlled; is the equivalent inductance of the motor to be controlled on the quadrature axis; is the equivalent voltage of the motor to be controlled on the quadrature axis; is the permanent magnet flux linkage of the motor to be controlled; is the stator current of the motor to be controlled; is the current angle of the motor to be controlled; The torque equation of the motor to be controlled is as follows:

[0014]

[0015] Wherein, is the electromagnetic torque of the motor to be controlled.

[0016] Furthermore, the current angle objective function of the motor to be controlled is as follows:

[0017] Wherein, is the current angle objective function of the motor to be controlled; is the current angle of the motor to be controlled; is the electromagnetic torque of the motor to be controlled; is the stator current of the motor to be controlled.

[0018] Furthermore, the polynomial description of the current angle objective function is as follows:

[0019] Among them, is the coefficient of the -th order expansion term in the polynomial description of the current angle objective function; is the coefficient of the -th order expansion term in the polynomial description of the current angle objective function; is the coefficient of the first-order expansion term in the polynomial description of the current angle objective function; is the coefficient of the zero-order expansion term in the polynomial description of the current angle objective function; is the expansion order, .

[0020] Furthermore, the interpretable objective function is as follows:

[0021] Among them, is the interpretable objective function; is the parameter describing the baseline of the current angle objective function; is the parameter describing the harmonic and periodic behavior of the motor model; is the parameter describing the influence of magnetic saturation of the motor model.

[0022] Furthermore, the process of solving the interpretable objective function to obtain the optimal current angle of the motor to be controlled includes: Solving the first derivative of the interpretable objective function to obtain the first derivative of the objective function with respect to the current angle; Setting the first derivative of the objective function with respect to the current angle to zero and calculating the optimal current angle of the motor to be controlled.

[0023] The present invention also provides an MTPA control system for a permanent magnet synchronous motor, including: A data acquisition module for acquiring the electromagnetic torque and stator current of the motor to be controlled; A function construction module for establishing the current angle objective function of the motor to be controlled with the goal of maximizing the ratio of the electromagnetic torque and stator current of the motor to be controlled; A polynomial description module for performing polynomial fitting on the current angle objective function of the motor to be controlled based on Taylor expansion to obtain the polynomial description of the current angle objective function; An explicit description module for explicitly describing the polynomial description of the current angle objective function according to the Kolmogorov - Arnold network to obtain the interpretable objective function; A function solving module for solving the interpretable objective function to obtain the optimal current angle of the motor to be controlled; An input control module for performing MTPA control on a motor to be controlled based on the optimal current angle of the motor to be controlled.

[0024] The present invention also provides an electronic device, comprising: A processor adapted to execute a computer program; A computer-readable storage medium storing a computer program, which when executed by the processor, executes the MTPA control method for the permanent magnet synchronous motor as described above.

[0025] The present invention also provides a computer-readable storage medium storing a computer program, which when executed by a processor, implements the MTPA control method for the permanent magnet synchronous motor.

[0026] Compared with the prior art, the beneficial effects of the present invention are: The present invention provides an MTPA control method for a permanent magnet synchronous motor, which uses Taylor expansion to perform polynomial fitting on the current angle objective function of the motor to be controlled, and uses the Kolmogorov - Arnold network to explicitly describe the polynomial description of the current angle objective function, thereby realizing the accurate calculation of the optimal current angle of the motor to be controlled, and performing MTPA control on the motor to be controlled with the optimal current angle, which can ensure the optimal distribution of the direct-axis current and the quadrature-axis current of the motor to be controlled, and realize the accurate control of the dynamic performance of the permanent magnet synchronous motor; the present invention does not require the inductor diagram or permanent magnet flux linkage parameters of the motor, can effectively reduce the dependence on complex mathematical models and high-frequency signal injection, and has the advantages of strong interpretability, high scalability, and high efficiency and simplicity; at the same time, it can reduce the influence of motor parameter changes, enhance the robustness of the MTPA control method; and improve the load disturbance and transient response, further reduce the copper loss, and improve the operating efficiency of the permanent magnet synchronous motor.

[0027] The MTPA control system, electronic device and computer-readable storage medium for the permanent magnet synchronous motor provided by the present invention have all the advantages of the above-mentioned MTPA control method for the permanent magnet synchronous motor. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application, and those of ordinary skill in the art can also obtain other drawings without creative efforts based on these drawings.

[0029] Figure 1 It is a flowchart of the MTPA control method for the permanent magnet synchronous motor provided in Embodiment 1; Figure 2 Schematic diagram of two-dimensional increase and decrease trend of current angle in Embodiment 1; Figure 3 Schematic diagram of three-dimensional increase and decrease trend of current angle in Embodiment 1; Figure 4 Block diagram of the MTPA control system of the permanent magnet synchronous motor provided in Embodiment 2; Figure 5 Block diagram of the electronic device provided in Embodiment 3. Detailed implementation manners

[0030] In order to make the technical problems, technical solutions and beneficial effects solved by the present application clearer and more understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application; obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the protection scope of the present application.

[0031] The present invention provides an MTPA control method for a permanent magnet synchronous motor, including the following steps: Step 100: Obtain the electromagnetic torque and stator current of the motor to be controlled. Among them, the motor to be controlled is a permanent magnet synchronous motor, and an MTPA (Maximum Torque Per Ampere) control module is provided in the motor to be controlled.

[0032] Step 200: Take the maximization of the ratio of the electromagnetic torque and stator current of the motor to be controlled as the goal, and establish an objective function of the current angle of the motor to be controlled.

[0033] Step 300: Based on Taylor expansion, perform polynomial fitting on the objective function of the current angle of the motor to be controlled to obtain a polynomial description of the objective function of the current angle.

[0034] Step 400: According to the Kolmogorov - Arnold Networks (KANs), perform an explicit description on the polynomial description of the objective function of the current angle to obtain an interpretable objective function.

[0035] Step 500: Solve the interpretable objective function to obtain the optimal current angle of the motor to be controlled.

[0036] Step 600: Based on the optimal current angle of the motor to be controlled, perform MTPA control on the motor to be controlled.

[0037] The present invention also provides an MTPA control system for a permanent magnet synchronous motor, comprising a data acquisition module, a function construction module, a polynomial description module, a display description module, a function solving module and an input control module.

[0038] The data acquisition module is used to acquire the electromagnetic torque and stator current of the motor to be controlled; the function construction module is used to establish a current angle objective function of the motor to be controlled with the goal of maximizing the ratio of the electromagnetic torque and stator current of the motor to be controlled; the polynomial description module is used to perform polynomial fitting on the current angle objective function of the motor to be controlled based on Taylor expansion to obtain a polynomial description of the current angle objective function; the explicit description module is used to perform explicit description on the polynomial description of the current angle objective function according to the Kolmogorov - Arnold network to obtain an interpretable objective function; the function solving module solves the interpretable objective function to obtain the optimal current angle of the motor to be controlled; the input control module is used to perform MTPA control on the motor to be controlled based on the optimal current angle of the motor to be controlled.

[0039] For the MTPA control method and system of the permanent magnet synchronous motor of the present invention, first, a current angle objective function of the motor to be controlled is established based on the electromagnetic torque and stator current of the motor to be controlled. Then, Taylor expansion is used to perform polynomial fitting on the current angle objective function of the motor to be controlled, and explicit description is performed on the polynomial description of the current angle objective function through the Kolmogorov - Arnold network to obtain an interpretable objective function. Furthermore, by solving the interpretable objective function, accurate calculation of the optimal current angle of the motor to be controlled is realized, and MTPA control is performed on the motor to be controlled with the optimal current angle, which can ensure the optimal distribution of the direct - axis current and quadrature - axis current of the motor to be controlled and achieve precise control of the dynamic performance of the permanent magnet synchronous motor.

[0040] In the present invention, when performing explicit description on the polynomial description of the current angle objective function through the Kolmogorov - Arnold network, by using the multi - layer non - linear activation function structure of the Kolmogorov - Arnold network, the relationship between the optimal current angle and motor parameters can be fitted in a more intuitive way, improving the interpretability of the current angle objective function of the motor to be controlled; secondly, the architecture of the Kolmogorov - Arnold network allows adding or reducing the number of layers and neurons to adapt to motor control tasks with different complexities, having high flexibility and scalability; in addition, it can greatly reduce the computational complexity and the required test data stream, and thus can quickly learn and fit an interpretable objective function from a small amount of data, thereby reducing the number of on - vehicle tests and costs of the motor to be controlled; moreover, it can respond to control requirements in real time, quickly estimate the optimal current angle, and is suitable for the fast dynamic response requirements of permanent magnet synchronous motors in electric aircraft.

[0041] The following uses some specific embodiments to further explain the MTPA control method of the permanent magnet synchronous motor provided by the present invention: Embodiment 1 In this Embodiment 1, the MTPA control process of an interior permanent magnet synchronous motor applied to an electric aircraft is taken as an example; as shown in the appendix Figure 1 A method for controlling MTPA of a permanent magnet synchronous motor is provided, including the following steps: Step 1: Obtain the electromagnetic torque and stator current of the motor to be controlled; wherein, the motor to be controlled is an interior permanent magnet synchronous motor applied to an electric aircraft, and an MTPA control module is provided in the interior permanent magnet synchronous motor. The MTPA control module is used to control the interior permanent magnet synchronous motor according to the MTPA angle.

[0042] It should be elaborated in detail that the process of obtaining the electromagnetic torque and stator current of the motor to be controlled is as follows: Step 11: Establish the MTPA control logic rule of the motor to be controlled according to the nonlinear equation of the motor to be controlled. Among them, the nonlinear equation of the motor to be controlled includes the steady-state voltage equation and the torque equation of the motor to be controlled.

[0043] Specifically, the steady-state voltage equation of the motor to be controlled is as follows:

[0044]

[0045]

[0046]

[0047] Among them, is the equivalent voltage of the motor to be controlled on the direct axis; is the stator resistance of the motor to be controlled; is the equivalent current of the motor to be controlled on the direct axis; is the equivalent inductance of the motor to be controlled on the direct axis; is the equivalent current of the motor to be controlled on the quadrature axis; is time; is the number of pole pairs of the motor to be controlled; is the mechanical rotor speed of the motor to be controlled; is the equivalent inductance of the motor to be controlled on the quadrature axis; is the equivalent voltage of the motor to be controlled on the quadrature axis; is the permanent magnet flux linkage of the motor to be controlled; is the stator current of the motor to be controlled; is the current angle of the motor to be controlled; Specifically, the torque equation of the motor to be controlled is as follows:

[0048]

[0049] Wherein, is the electromagnetic torque of the motor to be controlled.

[0050] It should be noted that the non-linear equation of the motor to be controlled can reflect the complex electromagnetic relationship inside the motor to be controlled. For example, it includes the interaction between electromagnetic torque, stator current, permanent magnet flux linkage, and current angle. Since the MTPA control strategy of the permanent magnet synchronous motor aims to achieve high-efficiency operation of the permanent magnet synchronous motor under different working conditions, by reasonably allocating the direct-axis current and quadrature-axis current, the current consumed when the permanent magnet synchronous motor outputs the same torque is minimized, thereby improving the efficiency and performance of the permanent magnet synchronous motor. Based on the non-linear equation of the motor to be controlled, establishing the MTPA control logic rule of the motor to be controlled can accurately determine the current distribution strategy according to the real-time operating state of the motor, providing a theoretical basis and control criterion for accurately obtaining the electromagnetic torque and stator current. Secondly, based on the MTPA control logic rule of the motor to be controlled, the current distribution of the motor to be controlled can be dynamically adjusted according to the torque and speed requirements of the electric aircraft for the motor to be controlled under different working conditions, ensuring the efficient and stable operation of the motor and meeting the power requirements of the electric aircraft.

[0051] Step 12: According to the MTPA control logic rule of the motor to be controlled, based on the preset current angle test value, obtain the electromagnetic torque and stator current of the motor to be controlled. Specifically, according to the MTPA control logic rule of the motor to be controlled, use the preset current angle test value as the test signal, collect data from the controller speed loop and torque sensor of the motor to be controlled respectively, and obtain the electromagnetic torque and stator current of the motor to be controlled. Among them, when collecting data from the controller speed loop of the motor to be controlled, the stator current of the motor to be controlled can be obtained; when collecting data from the torque sensor of the motor to be controlled, the electromagnetic torque of the motor to be controlled can be obtained.

[0052] It should be noted that the controller speed loop of the motor to be controlled is set in the control module of the motor to be controlled and is associated with the drive circuit of the motor to be controlled; the working principle of the controller speed loop includes: based on the feedback control theory, by collecting the rotational speed information of the motor to be controlled in real time and comparing it with the preset speed reference value; when there is a deviation between the rotational speed information of the motor to be controlled collected in real time and the preset speed reference value, the controller speed loop will adjust the output control signal according to the preset control method, thereby changing the input current of the motor to maintain the rotational speed stability of the motor to be controlled; when collecting data from the controller speed loop of the motor to be controlled, since the controller speed loop has the characteristic of controlling the motor current, by analyzing and calculating the control signal output by the controller speed loop, the stator current of the motor to be controlled can be obtained.

[0053] It should also be noted that the torque sensor of the motor to be controlled is installed between the output shaft of the motor to be controlled and the external load, and can accurately measure the magnitude of the torque transmitted by the output shaft of the motor to be controlled; preferably, the torque sensor of the motor to be controlled is a strain gauge torque sensor; the working principle of the strain gauge torque sensor includes: when the motor to be controlled is working, the output shaft will generate torque, and the strain gauge torque sensor will convert the torque into an electrical signal output based on the resistance strain effect, and the electromagnetic torque of the motor to be controlled can be obtained.

[0054] Step 2: Establish the current angle objective function of the motor to be controlled with the goal of maximizing the ratio of the electromagnetic torque to the stator current of the motor to be controlled. Among them, the current angle objective function of the motor to be controlled is as follows:

[0055] Among them, is the current angle objective function of the motor to be controlled; is the current angle of the motor to be controlled; is the electromagnetic torque of the motor to be controlled; is the stator current of the motor to be controlled.

[0056] It should be noted that in an interior permanent magnet synchronous motor, both the permanent magnet torque and the reluctance torque depend on the current angle; for a given stator current, the electromagnetic torque of the interior permanent magnet synchronous motor is a function of the current angle; among them, as the current angle increases from 0 to in the process, the function curve with respect to the current angle shows a trend of increasing first and then decreasing, as shown in Appendix Figures 2-3 shown; Appendix Figure 2 gives a two-dimensional increase and decrease trend schematic diagram of the current angle, and Appendix Figure 3 gives a three-dimensional increase and decrease trend schematic diagram of the current angle; from Appendix Figure 2It can be seen that when the stator current is 5A, 10A, and 15A, the function curves with respect to the current angle all show a trend of increasing first and then decreasing; at the same time, through actual measurement experiments, it is proved that the trend of the function curve with respect to the current angle of increasing first and then decreasing holds under different conditions, as shown in the appendix Figure 3 shown; therefore, there exists a specific current angle that can make the function with respect to the current angle reach the maximum value; that is, when the ratio of the electromagnetic torque of the motor to be controlled and the stator current is maximized, an objective function of the current angle of the motor to be controlled is established; based on the extreme value theorem, the vertex of the objective function of the current angle of the motor to be controlled is the optimal current angle of the motor to be controlled.

[0057] Step 3: Based on Taylor expansion, perform polynomial fitting on the objective function of the current angle of the motor to be controlled to obtain a polynomial description of the objective function of the current angle. Among them, the polynomial description of the objective function of the current angle is as follows:

[0058] Among them, is the coefficient of the -th order expansion term in the polynomial description of the objective function of the current angle; is the coefficient of the -th order expansion term in the polynomial description of the objective function of the current angle; is the coefficient of the first-order expansion term in the polynomial description of the objective function of the current angle; is the coefficient of the zero-order expansion term in the polynomial description of the objective function of the current angle; is the expansion order, .

[0059] Specifically, in the process of performing polynomial fitting on the objective function of the current angle of the motor to be controlled based on Taylor expansion to obtain a polynomial description of the objective function of the current angle, the least squares method or the method based on a predefined error function is used for Taylor expansion to perform polynomial fitting on the objective function of the current angle of the motor to be controlled.

[0060] The process of using the least squares method for Taylor expansion is applicable to low-order cases where the expansion order is 2 or 3; among them, the process of using the least squares method for Taylor expansion is as follows:

[0061] Among them, is the coefficient of the first-order expansion term in the polynomial description of the objective function of the current angle; is the coefficient of the second-order expansion term in the polynomial description of the objective function of the current angle; is the coefficient of the second-order expansion term in the polynomial description of the objective function of the current angle.

[0062] Taylor expansion is carried out by using the predefined error function method, which is applicable to high-order cases where the expansion order is greater than 3. Among them, the process of Taylor expansion by using the predefined error function method is as follows: Based on the preset current angle test value, the preset performance parameters of the motor to be controlled are calculated. Among them, the preset performance parameters of the motor to be controlled are, for example, electromagnetic power or motor efficiency. According to the preset current angle test value and the preset performance parameters of the motor to be controlled, an error function is constructed to obtain a predefined error function. The partial derivative of the predefined error function with respect to the expansion term coefficient is taken and set to zero to obtain a linear equation system. The linear equation system is solved to obtain the expansion term coefficients in the polynomial description of the current angle objective function. Finally, according to the expansion term coefficients in the polynomial description of the current angle objective function, the polynomial description of the current angle objective function can be obtained.

[0063] Among them, the predefined error function is:

[0064] Among them, is the predefined error function; is the th preset current angle test value; is the preset performance parameter of the motor to be controlled calculated based on the th preset current angle test value; is the number of preset current angle test values.

[0065] Step 4: According to the Kolmogorov - Arnold network, an explicit description of the polynomial description of the current angle objective function is carried out to obtain an interpretable objective function. Among them, the interpretable objective function is as follows:

[0066] Among them, is the interpretable objective function; is the parameter describing the baseline of the current angle objective function, which is used to reflect the characteristics of the current angle objective function in the basic state to determine the basic trend and approximate range of the current angle objective function; is the parameter describing the harmonic and periodic behavior of the motor model, which is used to quantify the influence of the harmonics and periodic characteristics generated during the operation of the motor on the current angle objective function; is the parameter describing the influence of magnetic saturation of the motor model, which is used to characterize the effect of the degree of magnetic saturation on the current angle objective function.

[0067] Specifically, the process of carrying out an explicit description of the polynomial description of the current angle objective function according to the Kolmogorov - Arnold network to obtain an interpretable objective function is as follows: Construct a feature vector based on the expansion term coefficients in the polynomial description of the current angle objective function and the preset sample data, where the preset sample data includes the current angle of the motor to be controlled and the electromagnetic torque of the motor to be controlled; input the feature vector into the Kolmogorov - Arnold network, and fit to obtain the parameters describing the baseline of the current angle objective function in the interpretable objective function , the parameters describing the harmonic and periodic behavior of the motor model and the parameters describing the influence of magnetic saturation of the motor model .

[0068] It should be noted that a polynomial is used to model the current angle objective function of the motor to be controlled. Based on the preset experimental data and using the Kolmogorov - Arnold network for curve fitting to identify the parameters in the interpretable objective function; when the current angle objective function of the motor to be controlled is represented in polynomial form and the polynomial description of the current angle objective function is explicitly described by the Kolmogorov - Arnold network, the optimal current angle of the motor to be controlled can be analyzed

[0069] It should also be noted that when inputting the feature vector into the Kolmogorov - Arnold network and fitting to obtain the parameters describing the baseline of the current angle objective function in the interpretable objective function , the parameters describing the harmonic and periodic behavior of the motor model and the parameters describing the influence of magnetic saturation of the motor model , during this process, through the backpropagation algorithm, calculate the error between the output of the Kolmogorov - Arnold network and the parameter target curve, and adjust the parameters of the Kolmogorov - Arnold network according to the error; through continuous iteration until the error converges to the preset range; where the parameter target curve is the expansion term coefficients in the polynomial description of the current angle objective function and the parameters describing the baseline of the current angle objective function , the parameters describing the harmonic and periodic behavior of the motor model and the parameters describing the influence of magnetic saturation of the motor model target curve

[0070] Step 5, solve the interpretable objective function to obtain the optimal current angle of the motor to be controlled. Specifically, the process of solving the interpretable objective function to obtain the optimal current angle of the motor to be controlled includes Step 51, solve the first - order derivative of the interpretable objective function to obtain the first - order derivative of the objective function with respect to the current angle

[0071] Step 52, set the first - order derivative of the objective function with respect to the current angle to zero, that is, set , and calculate to obtain the optimal current angle of the motor to be controlled

[0072] Step 6: Based on the optimal current angle of the motor to be controlled, perform MTPA control on the motor to be controlled. Specifically, input the optimal current angle of the motor to be controlled into the MTPA control module of the motor to be controlled to perform MTPA control on the motor to be controlled.

[0073] For the MTPA control method of the permanent magnet synchronous motor described in Embodiment 1, by accurately calculating the optimal current angle of the motor to be controlled and performing MTPA control on the motor to be controlled based on the optimal current angle, torque is output under the optimized stator current, realizing efficient MTPA control, and effectively reducing the additional losses brought by the high-frequency signal injection method; among them, using the Kolmogorov-Arnold network to achieve an explicit description of the polynomial description of the current angle objective function quickly and accurately can effectively overcome the problems that the traditional MTPA control method depends on complex mathematical models and signal injection techniques, and avoid the problems of low computational efficiency, poor interpretability, and difficulty in expansion.

[0074] In Embodiment 1, using the multi-layer non-linear activation function structure of the Kolmogorov-Arnold network can fit the relationship between the optimal current angle and the motor parameters in a more intuitive way; specifically, each layer of the non-linear activation function of the Kolmogorov-Arnold network can transform the input data to gradually extract the key features in the input data; for example, the first layer extracts the basic linear relationship features between current and torque, and the second layer mines the non-linear relationship features between the basic linear relationship features of current and torque and the optimal current angle on the basis of the first layer; in a progressive manner, the relationship between the complex motor parameters and the optimal current angle is gradually decomposed and presented; at the same time, the Kolmogorov-Arnold network allows a clear understanding of the control law of the motor, thereby improving interpretability.

[0075] Secondly, the architecture of the Kolmogorov - Arnold network allows for adding or reducing the number of layers and neurons to adapt to motor control tasks of different complexities. When determining the number of layers, for simple motor control tasks, such as the control of small - low - power permanent - magnet synchronous motors, the number of layers of the Kolmogorov - Arnold network is set to 2 - 3. For complex motor control tasks, such as the control of large - high - power permanent - magnet synchronous motors under variable working conditions, the number of layers of the Kolmogorov - Arnold network is set to 4 - 5 or more to fully extract and process complex features. When determining the number of neurons, it is initially set according to the dimension of the input data and the complexity of the task. For example, for cases where the dimension of the input data is low and the task is relatively simple, the number of neurons in each layer can be set to a relatively small number, such as 10 - 20. For cases where the dimension of the input data is high and the task is complex, the number of neurons in each layer can be increased accordingly, such as 50 - 100. Then, through the cross - validation method, training is carried out with different settings of the number of neurons, and the configuration of the number of neurons with the best performance is selected according to the training results. By flexibly adjusting the architecture of the Kolmogorov - Arnold network, it can be applied to various motor control scenarios from simple to complex, including but not limited to permanent - magnet synchronous motors of different power ratings and types. In addition, the network parameters of the Kolmogorov - Arnold network can be adjusted by preset machine - learning methods to adapt to new control requirements and environmental changes, further enhancing the scalability of the method.

[0076] Compared with the traditional signal - injection - based MTPA control method, the method described in Embodiment 1 can significantly reduce the computational complexity and the amount of test data required. Secondly, the Kolmogorov - Arnold network can quickly learn from a small amount of experimental data and fit an interpretable objective function, thus reducing the number of on - vehicle tests and costs. In addition, the Kolmogorov - Arnold network can also respond to control requirements in real - time, providing a means for quickly estimating the optimal current angle to meet the requirements of electric aircraft that require fast dynamic response.

[0077] Embodiment 2 As shown in the Figure 4 accompanying figure, Embodiment 2 provides an MTPA control system for a permanent - magnet synchronous motor, including a data acquisition module, a function construction module, a polynomial description module, a display description module, a function solving module, and an input control module.

[0078] A data acquisition module for acquiring the electromagnetic torque and stator current of the motor to be controlled; a function construction module for establishing a current angle objective function of the motor to be controlled with the maximization of the ratio of the electromagnetic torque and stator current of the motor to be controlled as the objective; a polynomial description module for performing polynomial fitting on the current angle objective function of the motor to be controlled based on Taylor expansion to obtain a polynomial description of the current angle objective function; an explicit description module for performing explicit description on the polynomial description of the current angle objective function according to the Kolmogorov-Arnold network to obtain an interpretable objective function; a function solving module for solving the interpretable objective function to obtain the optimal current angle of the motor to be controlled; an input control module for performing MTPA control on the motor to be controlled based on the optimal current angle of the motor to be controlled.

[0079] Embodiment 3 As shown in the Figure 5 accompanying drawings, Embodiment 3 of the present invention provides an electronic device, including: a memory for storing a computer program; a processor for implementing the steps of the MTPA control method of the permanent magnet synchronous motor when executing the computer program.

[0080] When the processor executes the computer program, it implements the steps of the above-mentioned MTPA control method of the permanent magnet synchronous motor, for example: Acquire the electromagnetic torque and stator current of the motor to be controlled. Among them, the motor to be controlled is a permanent magnet synchronous motor, and an MTPA control module is provided in the motor to be controlled; establish a current angle objective function of the motor to be controlled with the maximization of the ratio of the electromagnetic torque and stator current of the motor to be controlled as the objective; perform polynomial fitting on the current angle objective function of the motor to be controlled based on Taylor expansion to obtain a polynomial description of the current angle objective function; perform explicit description on the polynomial description of the current angle objective function according to the Kolmogorov-Arnold network to obtain an interpretable objective function; solve the interpretable objective function to obtain the optimal current angle of the motor to be controlled; perform MTPA control on the motor to be controlled based on the optimal current angle of the motor to be controlled.

[0081] Alternatively, when the processor executes the computer program, it implements the functions of each module in the above-mentioned MTPA control system of the permanent magnet synchronous motor, for example: A data acquisition module for acquiring the electromagnetic torque and stator current of the motor to be controlled; a function construction module for establishing an objective function of the current angle of the motor to be controlled with the maximization of the ratio of the electromagnetic torque and stator current of the motor to be controlled as the objective; a polynomial description module for performing polynomial fitting on the objective function of the current angle of the motor to be controlled based on Taylor expansion to obtain a polynomial description of the objective function of the current angle; an explicit description module for performing an explicit description on the polynomial description of the objective function of the current angle according to the Kolmogorov - Arnold network to obtain an interpretable objective function; a function solving module for solving the interpretable objective function to obtain the optimal current angle of the motor to be controlled; an input control module for performing MTPA control on the motor to be controlled based on the optimal current angle of the motor to be controlled.

[0082] Exemplarily, the computer program can be divided into one or more modules / units. The one or more modules / units are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of completing preset functions, and the instruction segments are used to describe the execution process of the computer program in the electronic device.

[0083] For example, the computer program can be divided into a data acquisition module, a function construction module, a polynomial description module, a display description module, a function solving module, and an input control module. The specific functions of each module are as follows: The data acquisition module is used to acquire the electromagnetic torque and stator current of the motor to be controlled; the function construction module is used to establish an objective function of the current angle of the motor to be controlled with the maximization of the ratio of the electromagnetic torque and stator current of the motor to be controlled as the objective; the polynomial description module is used to perform polynomial fitting on the objective function of the current angle of the motor to be controlled based on Taylor expansion to obtain a polynomial description of the objective function of the current angle; the explicit description module is used to perform an explicit description on the polynomial description of the objective function of the current angle according to the Kolmogorov - Arnold network to obtain an interpretable objective function; the function solving module is used to solve the interpretable objective function to obtain the optimal current angle of the motor to be controlled; the input control module is used to perform MTPA control on the motor to be controlled based on the optimal current angle of the motor to be controlled.

[0084] The electronic device can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The electronic device may include, but is not limited to, a processor and a memory. Those skilled in the art can understand that the above are examples of the electronic device and do not constitute a limitation on the electronic device. It may include more components than the above, or combine some components, or different components. For example, the electronic device may further include input / output devices, network access devices, a bus, etc.

[0085] The so-called processor may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor, or the processor may also be any conventional processor, etc. The processor is the control center of the electronic device and connects various parts of the entire electronic device through various interfaces and circuits.

[0086] The memory can be used to store the computer program and / or module. The processor realizes various functions of the electronic device by running or executing the computer program and / or module stored in the memory, and by calling the data stored in the memory.

[0087] The memory mainly includes a program storage area and a data storage area. Among them, the program storage area can store an operating system, application programs required for at least one function (such as a sound playback function, an image playback function, etc.); the data storage area can store data created according to the use of the mobile phone (such as audio data, phone book, etc.). In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one magnetic disk storage device, flash device, or other volatile solid-state storage devices.

[0088] Embodiment 4 Embodiment 4 of the present invention also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the MTPA control method for a permanent magnet synchronous motor are implemented.

[0089] If the modules / units integrated in the MTPA control system of the permanent magnet synchronous motor are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0090] Based on such understanding, all or part of the processes in the MTPA control method of the permanent magnet synchronous motor of the present invention can also be completed by instructing relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the MTPA control method of the permanent magnet synchronous motor can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or preset intermediate form, etc.

[0091] The computer-readable storage medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0092] The above embodiments are only one of the implementation manners capable of implementing the technical solution of the present invention. The scope of protection required by the present invention is not only limited by this embodiment, but also includes any changes, substitutions, and other implementation manners that are easily conceivable by those skilled in the art within the technical scope disclosed by the present invention.

Claims

1. A MTPA control method for a permanent magnet synchronous motor, characterized in that: include: Obtaining the electromagnetic torque and stator current of the motor to be controlled; Taking the maximization of the ratio of the electromagnetic torque and the stator current of the motor to be controlled as the goal, the current angle objective function of the motor to be controlled is established; Based on Taylor expansion, a polynomial fitting is performed on the current angle objective function of the motor to be controlled to obtain a polynomial description of the current angle objective function; According to the Kolmogorov-Arnold network, the polynomial description of the current angle objective function is explicitly described to obtain an interpretable objective function; Solve the interpretable objective function to obtain the optimal current angle of the motor to be controlled; Based on the optimal current angle of the motor to be controlled, MTPA control is performed on the motor to be controlled.

2. The MTPA control method of a permanent magnet synchronous motor according to claim 1, characterized in that: The process of obtaining the electromagnetic torque and stator current of the motor to be controlled includes: According to the nonlinear equation of the motor to be controlled, the MTPA control logic rule of the motor to be controlled is established; According to the MTPA control logic rule of the motor to be controlled and based on the preset current angle test value, the electromagnetic torque and stator current of the motor to be controlled are obtained.

3. The MTPA control method of a permanent magnet synchronous motor according to claim 2, characterized in that: The nonlinear equation of the motor to be controlled includes a steady-state voltage equation of the motor to be controlled and a torque equation of the motor to be controlled; The steady-state voltage equation of the motor to be controlled is as follows: in, is the equivalent voltage of the motor to be controlled on the direct axis; is the stator resistance of the motor to be controlled; is the equivalent current of the motor to be controlled on the direct axis; is the equivalent inductance of the motor to be controlled on the direct axis; is the equivalent current of the motor to be controlled on the quadrature axis; For time; is the number of pole pairs of the motor to be controlled; is the mechanical rotor speed of the motor to be controlled; is the equivalent inductance of the motor to be controlled on the quadrature axis; is the equivalent voltage of the motor to be controlled on the quadrature axis; is the permanent magnet flux of the motor to be controlled; is the stator current of the motor to be controlled; is the current angle of the motor to be controlled; The torque equation of the motor to be controlled is as follows: in, is the electromagnetic torque of the motor to be controlled.

4. The MTPA control method of a permanent magnet synchronous motor according to claim 1, characterized in that: The current angle objective function of the motor to be controlled is as follows: in, is the current angle objective function of the motor to be controlled; is the current angle of the motor to be controlled; is the electromagnetic torque of the motor to be controlled; is the stator current of the motor to be controlled.

5. The MTPA control method of a permanent magnet synchronous motor according to claim 4, characterized in that: The polynomial description of the current angle objective function is as follows: in, is the polynomial description of the current angle objective function. The coefficient of the order expansion term; is the polynomial description of the current angle objective function. The coefficient of the order expansion term; is the coefficient of the first-order expansion term in the polynomial description of the current angle objective function; is the coefficient of the zeroth order expansion term in the polynomial description of the current angle objective function; is the expansion order, .

6. The MTPA control method of a permanent magnet synchronous motor according to claim 5, characterized in that: The interpretable objective function is as follows: in, is an interpretable objective function; is the parameter describing the baseline of the current angle objective function; Parameters to describe the harmonic and periodic behavior of the motor model; is a parameter that describes the effect of magnetic saturation on the motor model.

7. The MTPA control method of a permanent magnet synchronous motor according to claim 6, characterized in that: The process of solving the interpretable objective function to obtain the optimal current angle of the motor to be controlled includes: Solve the first-order derivative of the interpretable objective function to obtain the first-order derivative of the objective function with respect to the current angle; The first-order derivative of the objective function with respect to the current angle is set to zero, and the optimal current angle of the motor to be controlled is calculated.

8. A MTPA control system for a permanent magnet synchronous motor, characterized in that: include: A data acquisition module, used for acquiring the electromagnetic torque and stator current of the motor to be controlled; A function building module, used for establishing a current angle objective function of the motor to be controlled with the goal of maximizing the ratio of the electromagnetic torque and the stator current of the motor to be controlled; A polynomial description module is used to perform polynomial fitting on the current angle target function of the motor to be controlled based on Taylor expansion to obtain a polynomial description of the current angle target function; An explicit description module is used to explicitly describe the polynomial description of the current angle objective function according to the Kolmogorov-Arnold network to obtain an interpretable objective function; The function solving module solves the interpretable objective function to obtain the optimal current angle of the motor to be controlled; The input control module is used to perform MTPA control on the motor to be controlled based on the optimal current angle of the motor to be controlled.

9. An electronic device, characterized in that: include: a processor suitable for executing a computer program; A computer-readable storage medium, wherein a computer program is stored in the computer-readable storage medium, and when the computer program is executed by the processor, the MTPA control method of the permanent magnet synchronous motor according to any one of claims 1 to 7 is executed.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the MTPA control method of the permanent magnet synchronous motor as described in any one of claims 1 to 7 is implemented.

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