Automatic calibration method and system for inductance matrix of permanent magnet synchronous motor

Abstract

The invention discloses a permanent magnet synchronous motor inductance matrix automatic calibration method and system, and the method comprises the steps: carrying out the system initialization, permanent magnet flux linkage reference calibration, weak magnetic region progressive current scanning, inductance parameter differential calculation and parameter integration, employing a positive and negative q-axis current symmetric excitation and differential operation mechanism as the core, and automatically counteracting the influence of a resistance item. Meanwhile, the weak magnetic working range of the d-axis current from-100A to-1000A is completely covered, and a full-working-condition inductance parameter two-dimensional mapping table is generated. The system does not need extra precision equipment, is small in algorithm calculation amount, is high in calibration efficiency, can adapt to batch application of a production line, can directly integrate a mapping table into a motor controller, achieves the real-time high-precision parameter calling through an interface function and two-dimensional linear interpolation, remarkably improves the torque precision and operation stability of field-weakening control of the permanent magnet synchronous motor, and is suitable for popularization and application. The method is suitable for motor parameter calibration in the fields of electric automobiles, industrial servo and the like.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, specifically to an automatic calibration method and system for the inductance matrix of a permanent magnet synchronous motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in key fields such as electric vehicles, industrial servos, and high-speed spindles due to their advantages of high power density, high efficiency, and fast response speed. In these applications, field weakening control is a core technology for extending the high-speed operating range of the motor, and the accuracy of field weakening control directly depends on the accuracy of the motor parameters in the field weakening region, especially the d / q axis inductance parameters. Because the motor's magnetic circuit exhibits deep saturation characteristics in the field weakening region, the d / q axis inductance shows a strong nonlinearity with current changes, making parameter acquisition significantly more difficult than under normal operating conditions.

[0003] Currently, the industry faces the following key challenges in calibrating the inductance parameters of permanent magnet synchronous motors:

[0004] 1. Parameter accuracy is greatly affected by resistance temperature drift: Traditional calibration methods are mostly based on voltage models to calculate inductance, which requires the accurate value of stator resistance R. However, the stator resistance changes significantly with the motor operating temperature, causing the calibration results to drift with temperature, which cannot meet the requirements of high-precision control.

[0005] 2. Incomplete coverage of the field weakening zone: Existing solutions mostly focus on parameter calibration under normal operating conditions, and there is insufficient research on the deep field weakening zone. They can only obtain local operating parameters and cannot reflect the nonlinear distribution of inductance in the field weakening zone, which leads to problems such as torque fluctuation and speed instability during field weakening control.

[0006] 3. Poor engineering practicality: Although some online identification algorithms can calculate parameters in real time, they require complex matrix operations and filtering, resulting in a large amount of computation, which cannot meet the high efficiency requirements of batch calibration on the production line; in addition, some solutions require the additional deployment of precision current sensors and temperature sensors, which increases equipment costs and integration difficulty.

[0007] Therefore, the industry urgently needs a permanent magnet synchronous motor inductance parameter calibration scheme that can automatically eliminate the influence of resistance, fully cover the weak magnetic field region, and is suitable for batch engineering applications, in order to overcome the shortcomings of existing technologies. Summary of the Invention

[0008] To address the issues of resistance temperature drift affecting accuracy, incomplete coverage of the field weakening region, and difficulties in engineering applications in existing technologies, this invention provides an automatic calibration method and system for inductance parameters in the field weakening region of a permanent magnet synchronous motor. This eliminates the influence of stator resistance temperature drift on calibration results, improving the accuracy of inductance parameters in the field weakening region. Simultaneously, it fully covers the field weakening operating range of -100A to -1000A d-axis current, obtaining the nonlinear distribution of inductance under all operating conditions. The algorithm logic is simplified, computational load is reduced, and it is suitable for batch calibration scenarios on production lines without requiring additional precision equipment. Furthermore, it forms an inductance parameter mapping table that can be directly integrated into the controller, supporting high-performance field weakening control.

[0009] The technical solution adopted in this invention is: an automatic calibration method for inductance parameters in the field weakening zone of a permanent magnet synchronous motor, comprising the following steps:

[0010] S1, System preparation and initialization: Install the motor under test on the dynamometer or drive it to rotate at a constant speed, ensuring that the motor controller is in a 0 torque operating state and that the CAN card and power analyzer are collecting data normally.

[0011] S2, Permanent magnet flux linkage reference value calibration: Set the d-axis current command to 0A, apply positive and negative q-axis current excitation sequences, and after maintaining the stability at each positive and negative current point for a preset time, collect the corresponding q-axis voltage. Calculate the permanent magnet flux linkage reference value corresponding to different absolute values ​​of q-axis current based on the collected voltage data.

[0012] S3, Progressive Current Scan in Weak Magnetic Zone: Progressive scanning is performed within a preset negative d-axis current range. Positive and negative q-axis current excitation sequences are applied to each d-axis current point. After stabilization at each (Id, Iq) operating point, d-axis voltage, q-axis voltage, d-axis current, q-axis current, and electric angular velocity are collected synchronously, and the average value of the collected data is taken as the steady-state measurement value.

[0013] S4, Inductance parameter differential calculation: Pair the positive and negative q-axis current measurement data under each d-axis current according to the absolute value, and calculate the d-axis inductance and q-axis inductance respectively based on the preset differential calculation formula to form a two-dimensional mapping table of inductance parameters in the weak magnetic region;

[0014] S5, Parameter Integration and Application: The two-dimensional mapping table is integrated into the motor controller, and parameter query is realized through interface functions. The controller internally adopts a two-dimensional linear interpolation algorithm to support high-precision parameter calling.

[0015] Furthermore, in step S2, the parameters of the positive and negative q-axis current excitation sequence are: initial value ±100A, termination value ±1000A, step size 100A, and stable holding time of each positive and negative current point 1 second.

[0016] Furthermore, in step S2, the formula for calculating the reference value of the permanent magnet flux linkage is:

[0017]

[0018] in, This is the measured voltage corresponding to the positive q-axis current. The measured voltage is the voltage corresponding to the negative q-axis current. ω is the electric angular velocity.

[0019] Furthermore, in step S3, the parameters of the preset negative d-axis current range are: starting value -100A, ending value -1000A, step size -100A; the parameters of the positive and negative q-axis current excitation sequence are the same as those in step S2.

[0020] Furthermore, in step S3, the specific method of data acquisition is as follows: data is synchronously acquired within the last 100ms after the working point stabilizes, and the average value of 100 data points is calculated as the steady-state measurement value of the working point.

[0021] Furthermore, in step S4, the formula for calculating the differential inductance along the d-axis is:

[0022]

[0023] in, This is the measured voltage corresponding to the positive q-axis current. The measured voltage is the voltage corresponding to the negative q-axis current. This is the current d-axis current. This is the reference value for the permanent magnet flux linkage corresponding to the absolute value of the q-axis current.

[0024] Furthermore, in step S4, the differential calculation formula for the q-axis inductance is:

[0025]

[0026] in, The d-axis measured voltage corresponds to the positive q-axis current. Iq is the d-axis measured voltage corresponding to the negative q-axis current, and |Iq| is the absolute value of the q-axis current.

[0027] Furthermore, in step S5, the interface functions include float get_Ld(float Id,float Iq) and float get_Lq(float Id,float Iq), which are used to query the d-axis inductance and q-axis inductance parameters, respectively.

[0028] The present invention also provides an automatic calibration system for inductance parameters in the field weakening zone of a permanent magnet synchronous motor, comprising a motor mounting module, a data acquisition module, a current excitation module, a parameter calculation module, and a controller integration module. The modules work together to execute the above calibration method to achieve automatic calibration of the inductance parameters in the field weakening zone of the permanent magnet synchronous motor.

[0029] Furthermore, the motor mounting module is a dynamometer or a drive motor, used to drive the motor under test to rotate at a constant speed; the data acquisition module includes a CAN card and a power analyzer, used to synchronously acquire voltage, current and electric angular velocity data; the current excitation module is used to output preset d-axis and q-axis current excitation sequences; the parameter calculation module is used to perform flux linkage reference value calculation and inductance differential calculation; the controller integration module is used to store a two-dimensional mapping table and provide a parameter query interface.

[0030] The beneficial effects of this invention are:

[0031] 1. Eliminate the influence of resistance temperature drift: Through symmetrical excitation and differential operation of positive and negative q-axis currents, the stator resistance term in the voltage equation is automatically canceled, eliminating the need to rely on the precise value of the resistance and completely solving the calibration accuracy problem caused by resistance temperature drift. The inductance parameter error is ≤3%.

[0032] 2. Complete coverage of the field weakening region: The system scans the deep field weakening region from -100A to -1000A of the d-axis current, obtains the inductance parameters of 100 operating points, fully reflects the nonlinear characteristics of the inductance in the field weakening region, and provides full-condition data support for high-precision field weakening control.

[0033] 3. High engineering practicality: The algorithm logic is simple, and the time for a single calibration is ≤5 minutes, which can be adapted to batch calibration on the production line; no additional precision equipment is required, and it can be implemented using existing dynamometers and power analyzers, thus reducing costs;

[0034] 4. Direct support for engineering applications: The generated two-dimensional mapping table can be directly integrated into the controller, and real-time parameter query can be realized through interface functions. Combined with the two-dimensional linear interpolation algorithm, it meets the real-time requirements of field weakening control and significantly improves the torque accuracy and stability of the motor when running at high speed. Attached Figure Description

[0035] Figure 1 This is a flowchart of the present invention;

[0036] Figure 2 This is a schematic diagram of the magnetic flux calculation process in this invention;

[0037] Figure 3 This is a schematic diagram of the d / q axis inductance calculation process in this invention. Detailed Implementation

[0038] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort. To facilitate understanding of the present invention, the present invention will be described in more detail below with reference to the accompanying drawings and specific embodiments.

[0039] This invention is a method for automatically calibrating the inductance parameters in the field weakening region of a permanent magnet synchronous motor, such as... Figure 1 As shown, it includes the following steps:

[0040] S1, System preparation and initialization: Install the motor under test on the dynamometer or drive it to rotate at a constant speed, ensuring that the motor controller is in a 0 torque operating state and that the CAN card and power analyzer are collecting data normally.

[0041] S2, Permanent magnet flux linkage reference value calibration, such as Figure 2 As shown: Set the d-axis current command: =0A, apply the q-axis current excitation sequence sequentially. The initial value of the q-axis current excitation sequence is ±100A, the final value is ±1000A, the step size is 100A, and the stable holding time at each positive and negative current point is 1 second; collect the corresponding q-axis voltage, and calculate the permanent magnet flux reference value corresponding to different absolute values ​​of q-axis current based on the collected voltage data.

[0042] The formula for calculating the reference value of permanent magnet flux linkage is:

[0043]

[0044] in, This is the measured voltage corresponding to the positive q-axis current. The measured voltage is the voltage corresponding to the negative q-axis current. ω is the electric angular velocity.

[0045] S3, Progressive Current Scan in the Weak Magnetic Region: A progressive scan is performed within a negative d-axis current range with an initial value of -100A, an ending value of -1000A, and a step size of -100A. For each d-axis current point, a positive and negative q-axis current excitation sequence is applied, with an initial value of ±100A, an ending value of ±1000A, and a step size of 100A. At each (Id, Iq) operating point, a current command is applied and a 1-second wait is initiated. Within the last 100ms after the operating point stabilizes, d-axis voltage, q-axis voltage, d-axis current, q-axis current, and electric angular velocity are simultaneously acquired. The average value of the 100 collected data points was used as the steady-state measurement value of the working point.

[0046] S4, Differential calculation of inductance parameters, such as Figure 3 As shown: For each d-axis current Id, the positive and negative q-axis current measurement data are paired by absolute value to establish data pairs. For example, for... =-100A, =100A, point A is (Id,+100A)→( , Point B is ( ), -100A)→( , Based on the preset differential calculation formula, the d-axis inductance and q-axis inductance are calculated respectively to form a two-dimensional mapping table of inductance parameters in the weak magnetic region;

[0047] The formula for calculating the differential inductance along the d-axis is:

[0048]

[0049] in, This is the measured voltage corresponding to the positive q-axis current. The measured voltage is the voltage corresponding to the negative q-axis current. This is the current d-axis current. This is the reference value for the permanent magnet flux linkage corresponding to the absolute value of the q-axis current;

[0050] The calculation covers the entire scan area, totaling 100. Data points;

[0051] The formula for calculating the differential inductance of the q-axis is:

[0052]

[0053] in, The d-axis measured voltage corresponds to the positive q-axis current. The d-axis measured voltage corresponds to the negative q-axis current. This represents the absolute value of the q-axis current.

[0054] The calculation covers the entire scan area, totaling 100. Data points.

[0055] S5, Parameter Integration and Application: The two-dimensional mapping table is integrated into the motor controller. The d-axis inductance and q-axis inductance parameters can be queried through the interface functions floatget_Ld(float Id,float Iq) and float get_Lq(float Id,float Iq). The controller internally uses a two-dimensional linear interpolation algorithm to support high-precision parameter calls. The control performance using fixed parameters and mapping table parameters is compared to verify the effect of improving torque output accuracy in the field weakening zone, and the high-speed operation stability and dynamic response characteristics are tested.

[0056] This invention also includes an automatic calibration system for inductance parameters in the field weakening zone of a permanent magnet synchronous motor, used to run the above-mentioned calibration method; it includes a motor mounting module, a data acquisition module, a current excitation module, a parameter calculation module, and a controller integration module; the motor mounting module is a dynamometer or a drive motor, used to drive the motor under test to rotate at a constant speed; the data acquisition module includes a CAN card and a power analyzer, used to synchronously acquire voltage, current, and electrical angular velocity data; the current excitation module is used to output preset d-axis and q-axis current excitation sequences; the parameter calculation module is used to perform flux linkage reference value calculation and inductance differential calculation; the controller integration module is used to store a two-dimensional mapping table and provide a parameter query interface; thus realizing the automatic calibration of inductance parameters in the field weakening zone of the permanent magnet synchronous motor.

[0057] The various embodiments described in this specification are presented 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. 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 permanent magnet synchronous motor inductance matrix automatic calibration method, characterized in that, The method comprises the following steps: S1, system preparation and initialization: the motor to be measured is installed on a dynamometer bench or is driven by a drag motor to rotate at a constant speed, it is ensured that the motor controller is in a 0-torque operation state, and the CAN card and the power analyzer data acquisition are normal; S2, permanent magnet flux linkage reference value calibration: the d-axis current command is set to 0 A, positive and negative q-axis current excitation sequences are applied, the corresponding q-axis voltage is collected after a preset time is stably maintained at each positive and negative current point, and the permanent magnet flux linkage reference values corresponding to different q-axis current absolute values are calculated based on the collected voltage data; S3, progressive current scanning in the field weakening region: progressive scanning is performed in a preset negative d-axis current range, positive and negative q-axis current excitation sequences are applied to each d-axis current point, and the d-axis voltage, the q-axis voltage, the d-axis current, the q-axis current and the electric angular velocity are synchronously collected after each (Id, Iq) operating point is stabilized, and the average value of the collected data is taken as a steady-state measurement value; S4, differential calculation of inductance parameters: the positive and negative q-axis current measurement data at each d-axis current are paired according to absolute values, the d-axis inductance and the q-axis inductance are respectively calculated based on a preset differential calculation formula, and a two-dimensional mapping table of inductance parameters in the field weakening region is formed; S5, parameter integration and application: the two-dimensional mapping table is integrated in the motor controller, parameter query is realized through an interface function, and a two-dimensional linear interpolation algorithm is used in the controller to support high-precision parameter calling.

2. The method of claim 1, wherein, In step S2, the parameters of the positive and negative q-axis current excitation sequences are as follows: the starting value is ±100 A, the terminal value is ±1000 A, the step length is 100 A, and the stable maintenance time of each positive and negative current point is 1 second.

3. The method of claim 1, wherein, In step S2, the calculation formula of the permanent magnet flux linkage reference value is as follows: wherein, is the measured voltage corresponding to positive q-axis current, is the measured voltage corresponding to negative q-axis current, is the electrical angular velocity.

4. The method of claim 1, wherein, In step S3, the parameters of the preset negative d-axis current range are as follows: the starting value is -100 A, the terminal value is -1000 A, and the step length is -100 A; and the parameters of the positive and negative q-axis current excitation sequences are consistent with those in step S2.

5. The method of claim 1, wherein, In step S3, the specific way of data collection is as follows: the data is synchronously collected within the last 100 ms after the operating point is stabilized, and the average value of 100 data points is taken as the steady-state measurement value of the operating point.

6. The method of claim 1, wherein, In step S4, the differential calculation formula of the d-axis inductance is as follows: wherein, is a measured voltage corresponding to positive q-axis current, is a measured voltage corresponding to negative q-axis current, is a current d-axis current, is a permanent magnet flux reference value corresponding to absolute value of q-axis current.

7. The method of claim 1, wherein, In step S4, the differential calculation formula of the q-axis inductance is as follows: wherein, is the d-axis measured voltage corresponding to positive q-axis current, is the d-axis measured voltage corresponding to negative q-axis current, |Iq| is the absolute value of q-axis current.

8. The method of claim 1, wherein, In step S5, the interface functions include float get_Ld(float Id, float Iq) and float get_Lq(float Id, float Iq), which are respectively used for querying the d-axis inductance and q-axis inductance parameters.

9. A permanent magnet synchronous motor inductance matrix automatic calibration system, characterized in that, The motor installation module, the data collection module, the current excitation module, the parameter calculation module and the controller integration module cooperatively execute the calibration method in any one of claims 1-8 to realize automatic calibration of the inductance parameters in the field weakening region of the permanent magnet synchronous motor.

10. The PMSM inductance matrix automatic calibration system of claim 9, wherein, The motor installation module is a dynamometer or a drag motor, which is used to drive the measured motor to rotate at a constant rotating speed; the data acquisition module includes a CAN card and a power analyzer, which are used to synchronously acquire voltage, current and electric angular velocity data; the current excitation module is used to output preset d-axis and q-axis current excitation sequences; the parameter calculation module is used to perform flux linkage reference value calculation and inductance difference calculation; and the controller integration module is used to store a two-dimensional mapping table and provide a parameter query interface.

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