Synchronous inductance determination method, apparatus and device, and computer readable storage medium

Abstract

The invention discloses a synchronous inductance determination method, device and equipment and a computer readable storage medium, and belongs to the field of synchronous motors. An inductance saturation curve model can be obtained (the inductance saturation curve model is obtained based on fitting of motor currents corresponding to different working conditions and actual inductance values of target synchronous inductance; the target current component of the motor current is not zero, and the non-target current component is zero; the target synchronous inductor is d-axis inductor or q-axis inductor, and the target current component is a stator current component coaxial with the target synchronous inductor; the non-target current component is the stator current component of the other orthogonal axis), so that in the operation process of the synchronous motor, the current inductance value of the target synchronous inductor of the synchronous motor is updated based on the real-time torque current and the inductance saturation curve model, and the stability and the operation efficiency of the synchronous motor are improved.

Description

Technical Field

[0001] This invention relates to the field of synchronous motors, and in particular to a method, apparatus, device, and computer-readable storage medium for determining synchronous inductance. Background Technology

[0002] With the widespread application of permanent magnet synchronous motors, higher requirements have been placed on motor operating efficiency. Sensorless vector control estimates the rotor position and rotor speed of the synchronous motor based on the motor's mathematical model. Compared with speed sensor-based vector control, it avoids the disadvantages of encoder wiring, such as cumbersome wiring, susceptibility to failure, and dependence on encoder installation.

[0003] In existing technologies, synchronous motors are typically controlled based on their static (i.e., fixed) parameters. For example, the synchronous inductors used (including d-axis and q-axis inductors) are static. However, in actual operation, the actual values ​​of these static parameters are not fixed. Using static parameters to control the synchronous motor will reduce its stability and operating efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a method, apparatus, device, and computer-readable storage medium for determining synchronous inductance. This invention allows for the acquisition of an inductance saturation curve model (the inductance saturation curve model is obtained by fitting the actual inductance value of the motor current and the target synchronous inductance under different operating conditions; the target current component of the motor current is not zero, and the non-target current component is zero; the target synchronous inductance is either the d-axis inductance or the q-axis inductance, the target current component is the stator current component coaxial with the target synchronous inductance, and the non-target current component is the stator current component of another orthogonal axis). Furthermore, during the operation of the synchronous motor, the current inductance value of the target synchronous inductance of the synchronous motor is updated based on the real-time torque current and the inductance saturation curve model, which is beneficial for improving the stability and operating efficiency of the synchronous motor.

[0005] To address the aforementioned technical problems, this invention provides a method for determining synchronous inductance, applied to a controller of a synchronous motor, comprising:

[0006] Obtain the inductance saturation curve model; the inductance saturation curve model is obtained by fitting the actual inductance value of the motor current and the target synchronous inductor under different operating conditions; the target current component of the motor current is not zero, and the non-target current component is zero;

[0007] Wherein, the target synchronizing inductor is a d-axis inductor or a q-axis inductor, the target current component is a stator current component coaxial with the target synchronizing inductor, and the non-target current component is a stator current component of another orthogonal axis.

[0008] During the operation of the synchronous motor, the current inductance value of the target synchronous inductance of the synchronous motor is updated based on the real-time torque current and inductance saturation curve model in order to control the operation of the synchronous motor.

[0009] On the other hand, the synchronous inductor is a q-axis inductor, the target current component is a q-axis current, and the non-target current component is a d-axis current; the steps for determining the inductor saturation curve model include:

[0010] Obtain the preset values ​​of q-axis current for different load conditions;

[0011] For each load condition, when the d-axis current is zero, the actual inductance value of the target synchronous inductor is determined based on the preset value of the q-axis current.

[0012] Based on the preset values ​​of the q-axis currents and their corresponding actual inductance values, the inductance saturation curve model of the target synchronous inductor with respect to the q-axis current is fitted to obtain the model.

[0013] On the other hand, determining the actual inductance value of the target synchronous inductor based on the preset value of the q-axis current for each load condition, when the d-axis current is zero, includes:

[0014] Determine the reference value of the q-axis current and its corresponding reference value for the reference load condition; the motor operates at the reference speed under the reference load condition.

[0015] Based on the stator voltage-current relationship in the synchronous rotating coordinate system, a reference relationship is constructed between the d-axis voltage value and the reference rotation speed, the q-axis inductance reference value, and the q-axis current reference value.

[0016] When the synchronous motor is running at the reference speed, for each load condition, the d-axis voltage value corresponding to the preset value of the q-axis current is measured when the d-axis current is zero.

[0017] For each load condition, a target relationship is constructed between the d-axis voltage value and the reference speed, the actual inductance value of the q-axis inductor, and the preset value of the q-axis current;

[0018] By simultaneously solving the reference relation and the target relation, the actual inductance value of the q-axis inductor corresponding to the preset value of the q-axis current is determined.

[0019] On the other hand, determining the q-axis current reference value and the corresponding q-axis inductance reference value corresponding to the reference load condition includes:

[0020] Determine the reference value for the q-axis current;

[0021] Under the condition that the d-axis current of the synchronous motor is zero and the q-axis current is the reference value of the q-axis current, determine the d-axis voltage value of the synchronous motor at two different preset speeds;

[0022] Based on the stator voltage-current relationship in the synchronous rotating coordinate system, the inductance value of the q-axis inductor is determined and used as the q-axis inductance reference value according to the d-axis voltage value of the synchronous motor at two different preset speeds, the q-axis current reference value, and the two preset speeds.

[0023] On the other hand, the process of fitting the inductance saturation curve model of the target synchronous inductor with respect to the q-axis current based on the preset values ​​of each q-axis current and their corresponding actual inductance values ​​includes:

[0024] A preset inductor saturation curve model is determined to characterize the saturation characteristics of the target synchronization inductor, and the inductor saturation curve model has undetermined parameters;

[0025] If the inductor saturation curve model is in a nonlinear form, the inductor saturation curve model is converted into a linear form.

[0026] Based on the preset values ​​of the q-axis currents and their corresponding actual inductance values, the undetermined parameters in the linear inductance saturation curve model are determined by the least squares method, so as to obtain an inductance saturation curve model with known undetermined parameters.

[0027] On the other hand, the process of determining the undetermined parameters in the linear inductor saturation curve model using the least squares method based on the preset values ​​of each q-axis current and their corresponding actual inductance values, so as to obtain an inductor saturation curve model with known undetermined parameters, includes:

[0028] Based on the actual inductance value corresponding to each preset q-axis current value, output observation data is constructed;

[0029] Based on the preset values ​​of each q-axis current, input observation data is constructed;

[0030] Based on the linear inductance saturation curve model, a linear mapping relationship between the output observation data and the input observation data is constructed;

[0031] Determine the cost function for the sum of squared errors between the predicted output of the characterization model and the observed output data;

[0032] By minimizing the cost function, the undetermined parameters in the linear mapping relationship are determined.

[0033] On the other hand, the synchronous motor includes a permanent magnet synchronous motor, a permanent magnet assisted synchronous reluctance motor, or a synchronous reluctance motor;

[0034] The inductor saturation curve model is used in the maximum torque-to-current ratio control, torque optimization control in the field weakening region, field weakening control, or unity power factor control of synchronous motors.

[0035] To address the aforementioned technical problems, the present invention also provides a device for determining the synchronous inductance, comprising:

[0036] The model acquisition module is used to acquire the inductance saturation curve model; the inductance saturation curve model is obtained by fitting the actual inductance value of the motor current and the target synchronous inductor under different operating conditions; the target current component of the motor current is not zero, and the non-target current component is zero;

[0037] Wherein, the target synchronizing inductor is a d-axis inductor or a q-axis inductor, the target current component is a stator current component coaxial with the target synchronizing inductor, and the non-target current component is a stator current component of another orthogonal axis.

[0038] The parameter update module is used to update the current inductance value of the target synchronous inductor of the motor based on the real-time torque current and inductance saturation curve model during motor operation, so as to control the operation of the motor.

[0039] To address the aforementioned technical problems, the present invention also provides a device for determining synchronous inductance, comprising:

[0040] Memory, used to store computer programs;

[0041] A processor, used to execute the computer program to implement the steps of the method for determining the synchronous inductor as described above.

[0042] To address the aforementioned technical problems, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method for determining the synchronous inductor as described above.

[0043] Beneficial Effects: This invention provides a method for determining synchronous inductance. Considering that the value of any synchronous inductance of a synchronous motor is affected by the coaxial stator current component, theoretically, an inductance saturation curve model of the target synchronous inductance with respect to the target current component (the stator current component coaxial with the target synchronous inductance) can be fitted. Therefore, this invention can obtain an inductance saturation curve model (the inductance saturation curve model is obtained by fitting the motor current and the actual inductance value of the target synchronous inductance under different operating conditions; the target current component of the motor current is not zero, and the non-target current component is zero; the target synchronous inductance is a d-axis inductance or a q-axis inductance, the target current component is the stator current component coaxial with the target synchronous inductance, and the non-target current component is the stator current component of another orthogonal axis). Then, during the operation of the synchronous motor, the current inductance value of the target synchronous inductance of the synchronous motor is updated based on the real-time torque current and the inductance saturation curve model, which is beneficial to improving the stability and operating efficiency of the synchronous motor.

[0044] The present invention also provides a device, apparatus and computer-readable storage medium for determining synchronous inductance, which have the same beneficial effects as the method for determining synchronous inductance described above. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention, the relevant technologies and the accompanying drawings used in 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.

[0046] Figure 1 A flowchart illustrating a method for determining a synchronous inductor provided by the present invention;

[0047] Figure 2 A flowchart illustrating another method for determining the synchronous inductor provided by the present invention;

[0048] Figure 3 A schematic diagram of the structure of a device for determining a synchronous inductor provided by the present invention;

[0049] Figure 4 This is a schematic diagram of the structure of a device for determining synchronous inductance provided by the present invention. Detailed Implementation

[0050] The core of this invention is to provide a method, apparatus, device, and computer-readable storage medium for determining synchronous inductance. This invention allows for the acquisition of an inductance saturation curve model (the inductance saturation curve model is obtained by fitting the actual inductance value of the motor current and the target synchronous inductance under different operating conditions; the target current component of the motor current is not zero, and the non-target current component is zero; the target synchronous inductance is either the d-axis inductance or the q-axis inductance, the target current component is the stator current component coaxial with the target synchronous inductance, and the non-target current component is the stator current component of another orthogonal axis). Furthermore, during the operation of the synchronous motor, the current inductance value of the target synchronous inductance of the synchronous motor is updated based on the real-time torque current and the inductance saturation curve model, which is beneficial for improving the stability and operating efficiency of the synchronous motor.

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating a method for determining a synchronous inductance provided by the present invention. This method is applied to a controller of a synchronous motor and includes:

[0053] S101: Obtain the inductor saturation curve model; the inductor saturation curve model is obtained by fitting the actual inductance value of the motor current and the target synchronous inductor under different operating conditions; the target current component of the motor current is not zero, and the non-target current component is zero;

[0054] Among them, the target synchronizing inductor is the d-axis inductor or the q-axis inductor, the target current component is the stator current component coaxial with the target synchronizing inductor, and the non-target current component is the stator current component of another orthogonal axis.

[0055] Specifically, considering the technical problems mentioned above, and taking into account that the value of any synchronous inductor in a synchronous motor is affected by the coaxial stator current component, theoretically, an inductance saturation curve model of the target synchronous inductor with respect to the target current component (the stator current component coaxial with the target synchronous inductor) can be fitted. Then, the inductance value of the target synchronous inductor can be dynamically determined based on the inductance saturation curve model. Therefore, the inductance saturation curve model can be obtained first in this step.

[0056] The inductor saturation curve model can be obtained by fitting the motor current and the actual inductance value of the target synchronous inductor under different operating conditions. In addition, since the cross-coupling effect can be eliminated by controlling the non-target current component to be zero, the target synchronous inductor only reflects the saturation characteristics caused by its coaxial current. Therefore, the target current component of the motor current (the stator current component coaxial with the target synchronous inductor) is not zero, and the non-target current component (the stator current component on the other orthogonal axis) is zero.

[0057] S102: During the operation of the synchronous motor, the current inductance value of the target synchronous inductance of the synchronous motor is updated based on the real-time torque current and inductance saturation curve model in order to control the operation of the synchronous motor.

[0058] Specifically, the inductance saturation curve model can be stored in the controller's storage unit. After obtaining the inductance saturation curve model, the controller can update the current inductance value of the target synchronous inductor of the synchronous motor based on the real-time torque current and the inductance saturation curve model during the operation of the synchronous motor, so as to control the operation of the synchronous motor.

[0059] The storage unit can be of various types, such as various types of non-volatile memory, etc., and the embodiments of the present invention are not limited thereto.

[0060] This invention provides a method for determining synchronous inductance. Considering that the value of any synchronous inductance of a synchronous motor is affected by the coaxial stator current component, theoretically, an inductance saturation curve model of the target synchronous inductance with respect to the target current component (the stator current component coaxial with the target synchronous inductance) can be fitted. Therefore, this invention can obtain an inductance saturation curve model (the inductance saturation curve model is obtained by fitting the motor current and the actual inductance value of the target synchronous inductance under different operating conditions; the target current component of the motor current is not zero, and the non-target current component is zero; the target synchronous inductance is a d-axis inductance or a q-axis inductance, the target current component is the stator current component coaxial with the target synchronous inductance, and the non-target current component is the stator current component of another orthogonal axis). Then, during the operation of the synchronous motor, the current inductance value of the target synchronous inductance of the synchronous motor is updated based on the real-time torque current and the inductance saturation curve model, which is beneficial to improving the stability and operating efficiency of the synchronous motor.

[0061] Based on the above embodiments:

[0062] As an optional embodiment, the synchronous inductor is a q-axis inductor, the target current component is the q-axis current, and the non-target current component is the d-axis current; the steps for determining the inductor saturation curve model include:

[0063] Obtain the preset values ​​of q-axis current for different load conditions;

[0064] For each load condition, with the d-axis current at zero, the actual inductance value of the target synchronous inductor is determined based on the preset value of the q-axis current.

[0065] Based on the preset values ​​of each q-axis current and their corresponding actual inductance values, the inductance saturation curve model of the target synchronous inductor with respect to the q-axis current is obtained by fitting.

[0066] Specifically, in this embodiment of the invention, the aim is to fit the inductance saturation curve model of the target synchronizing inductor with respect to the target current component. The prerequisite for fitting the inductance saturation curve model is to have data pairs of "current value of the target current component - actual inductance value of the target synchronizing inductor" for multiple target current component points. Therefore, in this step, multiple different preset current values ​​can be preset for the target current component. For any preset current value, when the target current component is the preset current value and the non-target current component is zero, the actual inductance value of the target synchronizing inductor is determined in order to construct the data pair of "current value of the target current component - actual inductance value of the target synchronizing inductor".

[0067] The reason for determining the actual inductance value when the non-target current component is zero is as follows: The d-axis inductance and q-axis inductance of the synchronous motor correspond to the magnetic circuit saturation state generated by the d-axis current and q-axis current, respectively. When the stator current components of both axes exist simultaneously, the magnetic circuit cross-saturation effect will cause the inductance values ​​to be mutually coupled, making it impossible to distinguish the change of a certain synchronous inductance caused only by the coaxial stator current component. By forcing the non-target current component to be zero, the cross-coupling effect can be eliminated, so that the target synchronous inductance only reflects the saturation characteristics caused by its coaxial current. The data pair of "current value of target current component - actual inductance value of target synchronous inductance" obtained under this condition can truly characterize the saturation law of the target synchronous inductance, providing a reliable basis for subsequent fitting of a high-precision inductance saturation curve model.

[0068] Specifically, the number of preset current values ​​must be greater than one, and each value must be different. The specific values ​​are not limited in this embodiment of the invention.

[0069] Specifically, the previous step can determine multiple data pairs of "current value of target current component - actual inductance value of target synchronous inductor" as the saturation characteristic dataset of the target synchronous inductor, so as to serve as the data basis for subsequent steps.

[0070] Specifically, considering the limited amount of data in the saturation characteristic dataset involving the "current value of the target current component - actual inductance value of the target synchronous inductor" data pair, it is difficult to determine the value of the target synchronous inductor corresponding to the current value of each target current component based on this saturation characteristic dataset. Therefore, in this step, an inductance saturation curve model of the target synchronous inductor with respect to the target current component can be fitted and determined based on the saturation characteristic dataset. In this way, when controlling the synchronous motor, the value of the target synchronous inductor can be dynamically determined based on the real-time value of the target current component and the inductance saturation curve model. This allows for more accurate control of the synchronous motor using the value of the target synchronous inductor, which is beneficial for improving the stability and operating efficiency of the synchronous motor.

[0071] Specifically, the inductor saturation curve model in this embodiment of the invention is applicable not only to sensorless vector control but also to sensor-based vector control. Sensorless vector control estimates the rotor position and rotor speed of the motor based on the motor mathematical model. Compared with sensor-based vector control, it avoids the disadvantages of encoder wiring, easy failure, and being affected by encoder installation. Moreover, sensorless vector control is basically based on the static model parameters of the motor. However, with the change of temperature and load, the motor parameters will deviate, affecting the magnetic field orientation, resulting in unstable control or decreased motor operating efficiency.

[0072] As an optional embodiment, for each load condition, when the d-axis current is zero, determining the actual inductance value of the target synchronous inductor based on the preset value of the q-axis current includes:

[0073] Determine the reference values ​​for the q-axis current and the corresponding q-axis inductance under the reference load condition; the motor operates at the reference speed under the reference load condition;

[0074] Based on the stator voltage and current relationship in the synchronous rotating coordinate system, a reference relationship is constructed between the d-axis voltage value and the reference rotational speed, the q-axis inductance reference value, and the q-axis current reference value.

[0075] When the synchronous motor is running at the reference speed, for each load condition, the d-axis voltage value corresponding to the preset value of the q-axis current is measured when the d-axis current is zero.

[0076] For each load condition, construct a target relationship between the d-axis voltage value and the reference speed, the actual inductance value of the q-axis inductor, and the preset value of the q-axis current;

[0077] By solving the reference equation and the target equation simultaneously, the actual inductance value of the q-axis inductor corresponding to the preset value of the q-axis current is determined.

[0078] Specifically, considering that the q-axis inductance varies significantly under the influence of the q-axis current, dynamically determining the q-axis inductance can significantly improve the stability and operating efficiency of the synchronous motor. Furthermore, considering that the q-axis inductance can be indirectly reflected by the d-axis voltage when the d-axis current is zero, but the d-axis voltage also depends on the motor speed, and speed measurement may have errors, the solution in this embodiment of the invention is as follows: First, a set of known reference parameters can be determined (the reference value of the q-axis current corresponding to the reference load condition and its corresponding q-axis inductance reference value). Then, by establishing d-axis voltage relationships between the reference condition and the target condition under the same reference speed (i.e., establishing reference relationships between the d-axis voltage value and the reference speed, q-axis inductance reference value, and q-axis current reference value, and target relationships between the d-axis voltage value and the reference speed, the actual inductance value of the q-axis inductance, and the preset value of the q-axis current), the simultaneous solutions are used to eliminate the influence of speed variables and determine the actual inductance value of the q-axis inductance corresponding to the preset value of the q-axis current. This allows for accurate identification of the q-axis inductance value under different preset q-axis current values ​​(corresponding to different loads) even without high-precision speed information, thus improving the robustness and engineering practicality of parameter identification.

[0079] Of course, besides this specific method, there are many other ways to "determine the actual inductance value of the target synchronous inductor based on the preset value of the q-axis current for each load condition when the d-axis current is zero". This embodiment of the invention does not limit the specific method.

[0080] In addition, when the target synchronizing inductor is a d-axis inductor, the steps for determining the inductor saturation curve model include:

[0081] Obtain the preset values ​​of d-axis current corresponding to different load conditions;

[0082] Under the condition that the q-axis current is controlled to be zero and the synchronous motor is in a stationary state, for any preset d-axis current value, a transient current excitation that rises from zero to the preset d-axis current value is applied to the d-axis, and the transient response signals of the d-axis voltage and d-axis current are acquired simultaneously.

[0083] Based on the d-axis voltage equation in a synchronous rotating coordinate system, the inductor voltage drop component induced by the d-axis current change rate is separated from the d-axis voltage. Based on the ratio of the inductor voltage drop component to the d-axis current change rate, the target d-axis inductance value corresponding to the preset d-axis current value is calculated.

[0084] Based on the preset values ​​of each d-axis current and their corresponding actual inductance values, the inductance saturation curve model of the target synchronous inductor with respect to the d-axis current is obtained by fitting.

[0085] Specifically, for a better explanation of the embodiments of the present invention, please refer to... Figure 2 , Figure 2A flowchart illustrating another method for determining the synchronous inductor provided by the present invention includes, in sequence, selecting a load T. L0 The motor was run at two different preset speeds ω1 and ω2, and the corresponding d-axis voltage u was recorded. d01 and u d02 ; Calculate the q-axis inductance reference value L q0 Control the motor to run at the reference speed; set the load T Lk To set the preset current value i qk Record the corresponding d-axis voltage u dn Determine the actual inductance value L of the d-axis inductor. dk ; Determine if all preset current values ​​have been detected. If not, return to step "Set load T". Lk To set the preset current value i qk If the detection is complete, the inductance saturation curve model of the target synchronous inductor is obtained by fitting the saturation characteristic dataset using the least squares method; the inductance saturation curve model is then stored in the storage unit of the synchronous motor controller; the specific process is described below:

[0086] The stator voltage-current relationship of the synchronous motor in the synchronous rotating coordinate system is as follows:

[0087] ;

[0088] In the formula, R s L is the stator resistance. d For the d-axis inductance, L q Let ω be the q-axis inductance, ω be the rotational speed, and ψ be the q-axis in r For the permanent magnet flux linkage of the motor rotor, u d For the d-axis voltage, u q Let i be the q-axis voltage. d Let i be the d-axis current. q This is the q-axis current;

[0089] Using i d When =0 control:

[0090] ;

[0091] Select a load T L0 The corresponding q-axis current is the q-axis current reference value i. q0 (This can also be considered as the preset current value of number 0). With the load unchanged, select two different preset speeds ω1 and ω2, and measure the d-axis voltage u respectively. d01 and u d02 :

[0092] ;

[0093] Calculate the load TL0 The q-axis inductance reference value L is below q0 :

[0094] ;

[0095] With the frequency ω2 remaining constant, the load is changed to T. L1 The corresponding q-axis current is the preset current value i1. q1 d-axis voltage u d11 i can be obtained q1 The corresponding objective relation (i.e., u as follows) d11 (relation), and refer to the relation (i.e., u as follows) d02 Solve the system of equations (the relational expression) and the target relational expression simultaneously:

[0096] ;

[0097] Calculate the preset current value i for No. 1 q1 The actual inductance value L q1 :

[0098] ;

[0099] Similarly, different preset values ​​of the q-axis current i can be obtained sequentially. q2 i q3 …i q(N-1) The actual inductance value L of the q-axis inductor q2 L q3 …L q(N-1) There are a total of N pairs of data.

[0100] As an optional embodiment, determining the q-axis current reference value and its corresponding q-axis inductance reference value corresponding to the reference load condition includes:

[0101] Determine the reference value for the q-axis current;

[0102] Determine the d-axis voltage values ​​of the synchronous motor at two different preset speeds, with the d-axis current controlled to be zero and the q-axis current set to a reference value.

[0103] Based on the stator voltage-current relationship in the synchronous rotating coordinate system, the inductance value of the q-axis inductor is determined and used as the q-axis inductance reference value according to the d-axis voltage value, q-axis current reference value, and the two preset speeds of the synchronous motor at two different preset speeds.

[0104] Specifically, considering the steady-state condition where the d-axis current is zero and the q-axis current is a reference value, the d-axis voltage equation... Even when the d-axis current is set to zero, there may still be a small d-axis current or measurement noise in the actual system, which may lead to inaccuracies in the data based solely on the d-axis voltage and speed at a single point. The calculation of the q-axis inductance is affected by the "residual term of stator resistance voltage drop," which impacts accuracy. To address this, the solution described in this embodiment of the invention is implemented. Under the same q-axis current reference value, the d-axis voltage values ​​of the synchronous motor are measured at two different preset speeds. Based on the stator voltage-current relationship in the synchronous rotating coordinate system, the inductance value of the q-axis inductance is determined according to the d-axis voltage values, the q-axis current reference value, and the two preset speeds. This value is then used as the q-axis inductance reference value. Theoretically, this eliminates the influence of stator resistance and zero-bias error on the inductance calculation, improves the accuracy of the q-axis inductance reference value identification, and provides a highly reliable benchmark for subsequent calculations.

[0105] Of course, in addition to this specific form, a set of reference parameters can also be determined in other forms, such as reference parameters given by staff obtained through a human-computer interaction device, etc. This embodiment of the invention does not limit the specific form.

[0106] As an optional embodiment, based on the preset values ​​of each q-axis current and their corresponding actual inductance values, the inductance saturation curve model of the target synchronous inductor with respect to the q-axis current is fitted, including:

[0107] A preset inductor saturation curve model is determined to characterize the saturation characteristics of the target synchronous inductor. The inductor saturation curve model has parameters to be determined.

[0108] When the inductor saturation curve model is in a nonlinear form, the inductor saturation curve model is converted into a linear form;

[0109] Based on the preset values ​​of each q-axis current and their corresponding actual inductance values, the undetermined parameters in the linear inductance saturation curve model are determined by the least squares method, so as to obtain an inductance saturation curve model with known undetermined parameters.

[0110] Specifically, considering that the least squares method has the advantages of high efficiency and good fitting effect, but the least squares method requires the model being fitted to be a linear model, while the inductance saturation curve model of the target synchronous inductor can theoretically have multiple forms, that is, the inductance saturation curve model is not necessarily linear. Therefore, the embodiments of the present invention can first determine a preset inductance saturation curve model (with undetermined parameters) used to characterize the saturation characteristics of the target synchronous inductor. Then, if the inductance saturation curve model is nonlinear, it is converted into a linear form. Finally, based on the saturation characteristic dataset, the undetermined parameters in the linear inductance saturation curve model can be determined by the least squares method, so as to obtain an inductance saturation curve model with known undetermined parameters.

[0111] Of course, in addition to the least squares method, other types of fitting methods can be used to fit the inductor saturation curve model, and the embodiments of the present invention are not limited here.

[0112] As an optional embodiment, based on the preset values ​​of each q-axis current and their corresponding actual inductance values, the undetermined parameters in the linear inductance saturation curve model are determined using the least squares method, so as to obtain an inductance saturation curve model with known undetermined parameters, including:

[0113] Based on the actual inductance values ​​corresponding to the preset values ​​of each q-axis current, output observation data is constructed;

[0114] Based on the preset values ​​of the currents along each q-axis, input observation data is constructed;

[0115] Based on the linear form of the inductance saturation curve model, a linear mapping relationship between the output observation data and the input observation data is constructed;

[0116] Determine the cost function for the sum of squared errors between the predicted output of the characterization model and the observed output data;

[0117] By minimizing the cost function, the undetermined parameters in the linear mapping relationship are determined.

[0118] Specifically, considering that for the linear form of the inductance saturation curve model, the input observation data and output observation data can be combined with it (the linear form of the inductance saturation curve model) to obtain the linear mapping relationship between the output observation data and the input observation data, and then the undetermined parameters in the linear mapping relationship can be determined by minimizing the constructed cost function, the scheme in the embodiment of the present invention was designed to efficiently and accurately determine the undetermined parameters of the inductance saturation curve model.

[0119] Of course, besides this specific form, "determining the undetermined parameters in the linear inductor saturation curve model by least squares method based on the saturation characteristic dataset" can also take many other forms, which are not limited in this embodiment of the invention.

[0120] Specifically, in a concrete example, the preset inductor saturation curve model with undetermined parameters can be:

[0121] ;

[0122] Among them, L q_init Both b and L are undetermined parameters. q_init is the unloaded inductance, and b is the saturation coefficient.

[0123] To facilitate subsequent least squares processing, the inductor saturation curve model is converted into a linear form:

[0124] ;

[0125] The linear form of the inductance saturation curve model can be denoted as, Where Y represents the output observation data and Φ represents the input observation data. Let be the vector of parameters to be determined, where:

[0126] The output observation data can be expressed as follows, combining the previously obtained actual inductance values ​​of each q-axis inductor:

[0127] ;

[0128] The input observation data can be expressed as follows, combining the previously obtained preset values ​​of each q-axis current:

[0129] ;

[0130] The vector of undetermined parameters can be expressed as:

[0131] ;

[0132] For the k-th observation data, the model prediction output is:

[0133] ;

[0134] in, For the model's predicted output, Let k be the input observation data for the kth time, where k∈[0,N-1];

[0135] The residual is the difference between the model-predicted output (estimated output) and the observed output (actual output) of the linear inductance saturation curve model.

[0136] ;

[0137] Where e(k) is the residual and y(k) is the kth output observation data;

[0138] The sum of squares of the residuals (i.e., the sum of squared errors) obtained from N sets of saturation characteristic datasets is used as the cost function J:

[0139] ;

[0140] The cost function J can be transformed into:

[0141] ;

[0142] Where E can be represented as:

[0143] ;

[0144] To minimize the cost function J, we can calculate J. Taking the first derivative of and setting it to 0, we get:

[0145] ;

[0146] If Φ is full rank, the undetermined parameter vector Solving the equation, we get:

[0147] ;

[0148] And it meets the following criteria:

[0149] ;

[0150] Therefore, the cost function J can be minimized at this point.

[0151] As an optional embodiment, the synchronous motor includes a permanent magnet synchronous motor, a permanent magnet assisted synchronous reluctance motor, or a synchronous reluctance motor;

[0152] The inductor saturation curve model is used in the maximum torque-to-current ratio control, torque optimization control in the field weakening region, field weakening control, or unity power factor control of synchronous motors.

[0153] Specifically, considering that the accuracy of the target synchronous inductance is crucial in maximum torque-to-current ratio (MTPA) control, torque optimization control in the field weakening region, field weakening control, or unity power factor control, and has a significant impact on the motor control effect, the inductance saturation curve model in this embodiment of the invention can be used in the maximum torque-to-current ratio control, torque optimization control in the field weakening region, field weakening control, or unity power factor control of synchronous motors. Furthermore, the accuracy of the target synchronous inductance is highly required during the controlled process of permanent magnet synchronous motors, permanent magnet assisted synchronous reluctance motors, or synchronous reluctance motors. Therefore, the method for determining the synchronous inductance can be applied to permanent magnet synchronous motors, permanent magnet assisted synchronous reluctance motors, or synchronous reluctance motors.

[0154] Of course, in addition to the specific forms mentioned above, there are many other applicable types of synchronous motors and applicable algorithms for inductance saturation curve models, which are not limited in this embodiment of the invention.

[0155] Please refer to Figure 3 , Figure 3 This is a schematic diagram of a device for determining a synchronization inductor provided by the present invention. The device for determining the synchronization inductor includes:

[0156] The model acquisition module 31 is used to acquire the inductance saturation curve model. The inductance saturation curve model is obtained by fitting the actual inductance value of the motor current and the target synchronous inductor under different operating conditions. The target current component of the motor current is not zero, and the non-target current component is zero.

[0157] Among them, the target synchronizing inductor is the d-axis inductor or the q-axis inductor, the target current component is the stator current component coaxial with the target synchronizing inductor, and the non-target current component is the stator current component of another orthogonal axis.

[0158] The parameter update module 32 is used to update the current inductance value of the target synchronous inductance of the motor based on the real-time torque current and inductance saturation curve model during motor operation, so as to control the motor operation. For a description of the synchronous inductance determination device provided in this embodiment of the invention, please refer to the aforementioned embodiment of the synchronous inductance determination method; this embodiment of the invention will not be repeated here.

[0159] Please refer to Figure 4 , Figure 4 This is a schematic diagram of a device for determining a synchronous inductance provided by the present invention. The device for determining the synchronous inductance includes:

[0160] Memory 41 is used to store computer programs;

[0161] The processor 42 is used to implement the steps of the method for determining the synchronous inductor as described in the foregoing embodiments when executing a computer program.

[0162] For a description of the device for determining the synchronous inductance provided in this embodiment of the invention, please refer to the aforementioned embodiment of the method for determining the synchronous inductance. This embodiment of the invention will not be repeated here.

[0163] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method for determining the synchronous inductor as described in the foregoing embodiments.

[0164] For a description of the computer-readable storage medium provided in the embodiments of the present invention, please refer to the aforementioned embodiments of the method for determining synchronous inductors; the embodiments of the present invention will not be repeated here.

[0165] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section. It should also be noted that in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0166] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of determining a synchronous inductance, characterized in that, A controller applied to a synchronous motor, comprising: An inductance saturation curve model is obtained, the inductance saturation curve model is fitted based on actual inductance values of target synchronous inductance corresponding to motor currents under different working conditions, a target current component of the motor current is not zero, and a non-target current component is zero; The target synchronous inductance is a d-axis inductance or a q-axis inductance, the target current component is a stator current component coaxial with the target synchronous inductance, and the non-target current component is a stator current component of another orthogonal axis; During synchronous motor operation, a current inductance value of the target synchronous inductance of the synchronous motor is updated based on real-time torque current and the inductance saturation curve model, so as to control the synchronous motor operation.

2. The method of determining the synchronous inductance according to claim 1, characterized in that, The synchronous inductance is a q-axis inductance, the target current component is a q-axis current, and the non-target current component is a d-axis current; The step of determining the inductance saturation curve model comprises: Q-axis current preset values corresponding to different load working conditions are obtained; For each load working condition, actual inductance values of the target synchronous inductance are determined based on the q-axis current preset values under the condition that the d-axis current is zero; An inductance saturation curve model of the target synchronous inductance with respect to the q-axis current is fitted according to the q-axis current preset values and the actual inductance values corresponding thereto.

3. The method of determining the synchronous inductance according to claim 2, characterized in that, The step of determining the actual inductance values of the target synchronous inductance based on the q-axis current preset values under the condition that the d-axis current is zero for each load working condition comprises: Q-axis current reference values corresponding to a reference load working condition and q-axis inductance reference values corresponding thereto are determined, the motor operates at a reference speed under the reference load working condition; A reference relationship between a d-axis voltage value, the reference speed, the q-axis inductance reference value and the q-axis current reference value is constructed based on a stator voltage and current relationship under a synchronous rotating coordinate system; Under the condition that the synchronous motor operates at the reference speed, a d-axis voltage value corresponding to the q-axis current preset value is measured under the condition that the d-axis current is zero for each load working condition; For each load working condition, a target relationship between the d-axis voltage value, the reference speed, an actual inductance value of the q-axis inductance and the q-axis current preset value is constructed; The actual inductance value of the q-axis inductance corresponding to the q-axis current preset value is determined by simultaneously solving the reference relationship and the target relationship.

4. The method of determining the synchronous inductance according to claim 3, characterized in that, The step of determining the q-axis current reference values corresponding to the reference load working condition and the q-axis inductance reference values corresponding thereto comprises: Q-axis current reference values are determined; D-axis voltage values of the synchronous motor under two different preset speeds are determined under the condition that the d-axis current of the synchronous motor is zero and the q-axis current is the q-axis current reference value; The inductance value of the q-axis inductance is determined based on the d-axis voltage values of the synchronous motor under the two different preset speeds, the q-axis current reference value and the two preset speeds according to the stator voltage and current relationship under the synchronous rotating coordinate system, and is taken as the q-axis inductance reference value.

5. The method of determining the synchronous inductance according to claim 3, wherein, The step of fitting the inductance saturation curve model of the target synchronous inductance with respect to the q-axis current according to the q-axis current preset values and the actual inductance values corresponding thereto comprises: The inductance saturation curve model for characterizing the saturation characteristic of the target synchronous inductance is determined, and the inductance saturation curve model has undetermined parameters; In the case that the inductance saturation curve model is in a nonlinear form, the inductance saturation curve model is converted into a linear form; According to each q-axis current preset value and the actual inductance value corresponding thereto, the undetermined parameters in the inductance saturation curve model in the linear form are determined by the least square method, so as to obtain the inductance saturation curve model with known undetermined parameters.

6. The method of determining the synchronous inductance according to claim 5, characterized in that, The method comprises the following steps: According to the actual inductance value corresponding to each q-axis current preset value, output observation data is constructed; According to each q-axis current preset value, input observation data is constructed; Based on the inductance saturation curve model in the linear form, a linear mapping relationship between the output observation data and the input observation data is constructed; A cost function for error square sum between the model prediction output and the output observation data is determined; By minimizing the cost function, the undetermined parameters in the linear mapping relationship are determined.

7. The method of determining the synchronous inductance according to any one of claims 1 to 6, characterized in that, The synchronous motor comprises a permanent magnet synchronous motor, a permanent magnet auxiliary synchronous reluctance motor or a synchronous reluctance motor; The inductance saturation curve model is used in maximum torque current ratio control, torque optimization control in a field weakening region, field weakening control or unit power factor control of the synchronous motor.

8. A determination device of a synchronous inductance, characterized in that, The method comprises the following steps: A model acquisition module is configured to acquire an inductance saturation curve model; The inductance saturation curve model is fitted based on motor currents and actual inductance values of target synchronous inductances corresponding to different working conditions; the target current component of the motor current is not zero, and the non-target current component is zero; The target synchronous inductance is a d-axis inductance or a q-axis inductance, the target current component is a stator current component coaxial with the target synchronous inductance, and the non-target current component is a stator current component of another orthogonal axis; A parameter update module is configured to update a current inductance value of the target synchronous inductance of the motor based on real-time torque currents and the inductance saturation curve model during motor operation, so as to control the motor operation.

9. A device for determining the synchronous inductance, characterized by The method comprises the following steps: A memory is configured to store a computer program; A processor is configured to implement the steps of the method for determining the synchronous inductance according to any one of claims 1 to 7 when the computer program is executed.

10. A computer-readable storage medium, characterized in that, The computer program is stored on the computer readable storage medium, and the computer program is executed by the processor to implement the steps of the method for determining the synchronous inductance according to any one of claims 1 to 7.

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