Permanent magnet synchronous motor magnetic weakening closed-loop regulation method and device

Abstract

This disclosure relates to a closed-loop field-weakening regulation method and device for a permanent magnet synchronous motor. This method relates to the field of vehicle motor control and addresses the issue of motor current oscillation caused by voltage reduction. The method comprises: obtaining a voltage deviation between the motor voltage and the maximum output voltage; obtaining a gain factor corresponding to the voltage deviation; and deriving an excitation current based on the voltage deviation and the gain factor. The technical solution provided by this disclosure is applicable to motor-driven vehicles and implements an accurate and efficient excitation current generation mechanism.

Description

Technical Field

[0001] The present disclosure relates to the field of vehicle motor control, and in particular to a method and device for regulating a permanent magnet synchronous motor with a weakened magnetic field. Background Art

[0002] Industrial vehicles are often driven by electric motors, which utilize speed control. As motor speed increases, the motor voltage and, consequently, the motor controller's output voltage, rise accordingly. However, the busbar and motor controller capacities are limited, and thus the motor controller's output voltage is also limited. When the motor controller's output voltage reaches saturation, it can be stepped down by applying a reverse excitation current, Id, to reduce the motor voltage and further increase the speed.

[0003] In engineering, a software closed-loop approach can be used to implement the voltage reduction process. The speed loop outputs the torque current Iq, which is integrally adjusted using the maximum output voltage and the controller output voltage. It then outputs the excitation current Id, which is then controlled by the current loop to control motor operation. Due to the complex and diverse operating conditions of a vehicle, the integral gain may not be appropriate for the current state, resulting in poor feedback voltage reduction and even other problems. For example, during acceleration, regulation lag may occur, causing uncontrolled motor current; or Id and Iq may pull against each other, causing violent torque fluctuations and vehicle vibration. Summary of the Invention

[0004] To overcome the problems existing in related technologies, this disclosure provides a closed-loop field-weakening regulation method and apparatus for a permanent magnet synchronous motor. The integral gain can be flexibly selected based on actual operating conditions to ensure that the basic excitation current effectively regulates the motor voltage, thus resolving the problem of motor current oscillation caused by voltage reduction.

[0005] According to a first aspect of an embodiment of the present disclosure, a method for weakening magnetic field closed-loop regulation of a permanent magnet synchronous motor is provided, comprising:

[0006] Get the voltage deviation between the motor voltage and the maximum output voltage;

[0007] Obtaining a gain coefficient corresponding to the voltage deviation;

[0008] An excitation current is obtained according to the voltage deviation and the gain coefficient.

[0009] Furthermore, the step of obtaining a voltage deviation between the motor voltage and the maximum output voltage includes:

[0010] The motor voltage is obtained by calculating the direct-axis voltage and the quadrature-axis voltage;

[0011] Calculating the maximum output voltage according to the bus voltage;

[0012] Calculate the voltage deviation:

[0013] Voltage deviation = maximum output voltage - motor voltage.

[0014] Furthermore, the step of obtaining the gain coefficient corresponding to the voltage deviation includes:

[0015] Obtaining a gain coefficient that matches the voltage deviation from preset integral gain configuration data, wherein the gain configuration data includes a correspondence between multiple sets of voltage deviation values ​​and gain coefficients;

[0016] Among them, the voltage deviation 0, the gain coefficient decreases as the voltage deviation increases.

[0017] The voltage deviation When the absolute value of the voltage deviation increases, the gain coefficient increases.

[0018] Furthermore, the method further comprises:

[0019] The excitation current and torque current are limited according to the current maximum motor current, an excitation current given value and a torque current given value are obtained, and the current loop is instructed to perform current loop adjustment according to the excitation current given value and the torque current given value.

[0020] Furthermore, the step of performing amplitude limiting processing on the excitation current and the torque current to obtain a given excitation current value and a given torque current value includes:

[0021] According to the preset motor speed and maximum motor current correspondence curve, the maximum motor current corresponding to the current motor speed is obtained;

[0022] When the following expressions are met, the torque current and / or the excitation current are reduced to obtain the torque current given value and / or the excitation current given value:

[0023] .

[0024] Furthermore, the gain coefficient is an integral gain coefficient or a proportional gain coefficient.

[0025] According to a second aspect of an embodiment of the present disclosure, a permanent magnet synchronous motor field weakening closed-loop regulation device is provided, comprising:

[0026] A voltage deviation acquisition module is used to obtain the voltage deviation between the motor voltage and the maximum output voltage;

[0027] A gain coefficient acquisition module, used to obtain the gain coefficient corresponding to the voltage deviation;

[0028] The excitation current acquisition module is used to obtain the excitation current according to the voltage deviation and the gain coefficient.

[0029] Furthermore, the voltage deviation acquisition module includes:

[0030] A motor voltage acquisition submodule, configured to calculate the motor voltage based on the direct-axis voltage and the quadrature-axis voltage;

[0031] A maximum output voltage acquisition submodule, configured to calculate the maximum output voltage according to the bus voltage;

[0032] The deviation calculation submodule is used to calculate the voltage deviation:

[0033] Voltage deviation = maximum output voltage - motor voltage.

[0034] Furthermore, the gain coefficient acquisition module is specifically configured to acquire a gain coefficient that matches the voltage deviation from preset integral gain configuration data, wherein the gain configuration data includes a correspondence between multiple sets of voltage deviation values ​​and gain coefficients;

[0035] Among them, the voltage deviation 0, the gain coefficient decreases as the voltage deviation increases.

[0036] The voltage deviation When the absolute value of the voltage deviation increases, the gain coefficient increases.

[0037] Furthermore, the device further comprises:

[0038] The limiting processing module is used to limit the excitation current and torque current according to the current maximum motor current, obtain the excitation current set value and the torque current set value, and instruct the current loop to adjust the current loop according to the excitation current set value and the torque current set value.

[0039] The technical solutions provided by the embodiments of the present disclosure may have the following beneficial effects: obtaining the voltage deviation between the motor voltage and the maximum output voltage, then obtaining the gain coefficient corresponding to the voltage deviation, and then deriving the excitation current based on the voltage deviation and the gain coefficient. The gain system used is determined based on the voltage deviation in the current operating state, and the excitation current is then derived. This implements an accurate and effective excitation current generation mechanism, resolving the problem of motor current oscillation caused by voltage reduction.

[0040] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0042] Figure 1 The present invention is a flow chart showing a method for weakening magnetic field closed-loop regulation of a permanent magnet synchronous motor according to an exemplary embodiment.

[0043] Figure 2 The flowchart of another method for weakening magnetic field closed-loop regulation of a permanent magnet synchronous motor is shown according to an exemplary embodiment.

[0044] Figure 3 The flowchart of another method for weakening magnetic field closed-loop regulation of a permanent magnet synchronous motor is shown according to an exemplary embodiment.

[0045] Figure 4 The figure is a block diagram of another permanent magnet synchronous motor field weakening closed-loop regulation system according to an exemplary embodiment.

[0046] Figure 5 The figure is a block diagram of a closed-loop regulation device for a permanent magnet synchronous motor according to an exemplary embodiment.

[0047] Figure 6 is a structural block diagram of a voltage deviation acquisition module 501 according to an exemplary embodiment.

[0048] Figure 7 It is a block diagram of another closed-loop regulation device for a permanent magnet synchronous motor according to an exemplary embodiment. DETAILED DESCRIPTION

[0049] Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. In the following description, when referring to the drawings, like numbers in different figures represent like or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present invention, as detailed in the appended claims.

[0050] In engineering, a software closed-loop approach can be used to implement the voltage reduction process. The speed loop outputs the torque current Iq, which is integrally adjusted using the maximum output voltage and the controller output voltage. It then outputs the excitation current Id, which is then controlled by the current loop to control motor operation. Due to the complex and diverse operating conditions of a vehicle, the integral gain may not be appropriate for the current state, resulting in poor feedback voltage reduction and even other problems. For example, during acceleration, regulation lag may occur, causing uncontrolled motor current; or Id and Iq may pull against each other, causing violent torque fluctuations and vehicle vibration.

[0051] To address these issues, embodiments of the present disclosure provide a closed-loop field-weakening regulation method and apparatus for a permanent magnet synchronous motor. This method uses the voltage deviation in the current operating state to determine the gain system used to generate the excitation current. This provides an accurate and effective mechanism for generating the excitation current, resolving the issue of motor current oscillation caused by voltage reduction.

[0052] An exemplary embodiment of the present disclosure provides a method for weakening magnetic closed-loop regulation of a permanent magnet synchronous motor. The process of performing weakening magnetic closed-loop regulation using this method is as follows: Figure 1 Shown, including:

[0053] Step 101: Obtain a voltage deviation between the motor voltage and the maximum output voltage.

[0054] In this step, when performing weak magnetic closed-loop regulation, the motor voltage and maximum output voltage are calculated in real time, and the voltage deviation is calculated accordingly. Figure 2 Shown, including:

[0055] Step 201: Calculate the motor voltage according to the direct-axis voltage and the quadrature-axis voltage.

[0056] Step 202: Calculate and obtain the maximum output voltage according to the bus voltage.

[0057] It should be noted that there is no strict time sequence relationship between step 201 and step 202, and they can be obtained by different threads respectively. The time requirement for obtaining the motor voltage and the maximum output voltage in real time can be set according to actual application needs.

[0058] Step 203: Calculate the voltage deviation.

[0059] In this step, the voltage deviation is calculated according to the following expression:

[0060] Voltage deviation = maximum output voltage - motor voltage.

[0061] Step 102: Obtain a gain coefficient corresponding to the voltage deviation.

[0062] A gain coefficient matching the voltage deviation is obtained from preset integral gain configuration data, wherein the gain configuration data includes a plurality of corresponding relationships between voltage deviation values ​​and gain coefficients.

[0063] Among them, the voltage deviation 0, the gain coefficient decreases as the voltage deviation increases; When the absolute value of the voltage deviation increases, the gain coefficient increases.

[0064] The gain coefficient may be an integral gain coefficient or a proportional gain coefficient.

[0065] When using the integral gain coefficient, the voltage deviation is adjusted by the integral action. As long as the voltage deviation exists, the integral action will be carried out, that is, the voltage deviation is integrated to make the output continue to increase or decrease.

[0066] When using a proportional gain coefficient, the voltage deviation is adjusted using the proportional action. The proportional action proportionally reflects the deviation of the control system. Once a deviation occurs, the proportional part immediately takes control action to reduce the deviation.

[0067] According to one embodiment, the gain coefficient may also be a fixed value.

[0068] Step 103: Obtain an excitation current according to the voltage deviation and the gain coefficient.

[0069] In this step, the excitation current is calculated based on the voltage deviation and the gain coefficient.

[0070] An exemplary embodiment of the present disclosure also provides a method for weak magnetic closed-loop regulation of a permanent magnet synchronous motor. After the excitation current is calculated, further amplitude limiting processing can be performed to maintain the balance of the motor voltage, ensure the system stability during the weak magnetic closed-loop regulation process, and avoid oscillation of the motor current. Specifically, the excitation current and torque current can be limited according to the current maximum motor current, and the excitation current set value and the torque current set value can be obtained, and the current loop can be instructed to perform current loop regulation according to the excitation current set value and the torque current set value. The process is as follows Figure 3 Shown, including:

[0071] Step 301: Obtain the maximum motor current corresponding to the current motor speed according to a preset curve of correspondence between motor speed and maximum motor current.

[0072] In this step, the correspondence between the motor speed and the maximum motor current can be preset. According to one embodiment, a curve of the correspondence between the motor speed and the maximum motor current can be set.

[0073] According to one embodiment, the actual motor speed and the current maximum torque current The relationship curve is used as the limit value of the output torque current or excitation current, and the process is more stable and the adaptability is better.

[0074] Step 302: When a preset condition is met, reduce the torque current and / or the excitation current to obtain the torque current set value and / or the excitation current set value.

[0075] According to one embodiment, a limiting condition may be preset. The limiting condition is specifically expressed as the following expression. When the following expression is met, the torque current and / or the excitation current is reduced to obtain the torque current given value and / or the excitation current given value:

[0076] .

[0077] For example, if the above expression is not satisfied, the torque current is reduced. After the torque current is reduced, it is verified again whether the above expression is satisfied. If so, it is determined that no further limiting processing is required, and the final torque current set value and / or the excitation current set value are output.

[0078] An exemplary embodiment of the present disclosure further provides a permanent magnet synchronous motor field weakening closed-loop regulation system, the architecture block diagram of which is as follows: Figure 4 Shown, including:

[0079] Speed ​​loop, current circle limit module, current loop, motor.

[0080] The speed loop is a universal module used to adjust the speed of the motor according to the actual With command speed Perform pi adjustment to obtain a given torque current .

[0081] Current circle limiting module, used to adjust the current according to the actual speed of the motor Look up the pre-set table to get the current maximum motor current , the given torque current is given With integral regulation output Do the limiting process so that and Obtained The maximum motor current at the within .exist Beyond After the limit, reduce Make Less than or equal to , its final output and .

[0082] The current loop is a universal module used to and Perform current loop adjustment and output direct axis given voltage and quadrature axis given voltage , and control the motor operation.

[0083] According to one embodiment, the system further includes a voltage calculation module, a voltage deviation calculation module, an integral gain calculation module and an integral regulator.

[0084] Among them, the voltage calculation module is used to calculate the direct axis voltage output by the current loop and quadrature axis voltage Calculating motor voltage , calculate the maximum output voltage based on the bus voltage obtained by electronic control sampling .

[0085] According to one embodiment, .

[0086] Voltage deviation calculation module, used to use minus Get voltage deviation .

[0087] Integral gain calculation module for using voltage deviation Calculate the integral gain coefficient U-Ki. In the embodiment of the present invention, the integral gain coefficient is used as the gain coefficient for calculation. According to one embodiment, when the voltage deviation is greater than or equal to 0, the greater the deviation, the smaller the integral gain; when the voltage deviation is less than 0, the greater the deviation, the greater the integral gain.

[0088] Integral gain coefficient U-Ki and voltage deviation Input to the integral regulator, output .

[0089] The integral adjustment module is a universal module that performs integral adjustment output according to the integral gain system U-Ki and the voltage deviation Uerr .

[0090] An exemplary embodiment of the present disclosure further provides a closed-loop regulation device for a permanent magnet synchronous motor. The structure of the device is as follows: Figure 5 Shown, including:

[0091] A voltage deviation acquisition module 501 is used to acquire a voltage deviation between the motor voltage and the maximum output voltage;

[0092] A gain coefficient acquisition module 502 is configured to acquire a gain coefficient corresponding to the voltage deviation;

[0093] The excitation current acquisition module 503 is configured to obtain the excitation current according to the voltage deviation and the gain coefficient.

[0094] Furthermore, the structure of the voltage deviation acquisition module 501 is as follows: Figure 6 Shown, including:

[0095] The motor voltage acquisition submodule 601 is configured to calculate the motor voltage based on the direct-axis voltage and the quadrature-axis voltage;

[0096] The maximum output voltage acquisition submodule 602 is configured to calculate the maximum output voltage according to the bus voltage;

[0097] The deviation calculation submodule 603 is used to calculate the voltage deviation:

[0098] Voltage deviation = maximum output voltage - motor voltage.

[0099] Furthermore, the gain coefficient acquisition module 502 is specifically configured to acquire a gain coefficient that matches the voltage deviation from preset integral gain configuration data, wherein the gain configuration data includes a correspondence between multiple sets of voltage deviation values ​​and gain coefficients;

[0100] Among them, the voltage deviation 0, the gain coefficient decreases as the voltage deviation increases.

[0101] The voltage deviation When the absolute value of the voltage deviation increases, the gain coefficient increases.

[0102] Furthermore, the structure of the device is as follows Figure 7 As shown, it also includes:

[0103] The amplitude limiting processing module 504 is used to limit the excitation current and torque current according to the current maximum motor current, obtain the excitation current set value and the torque current set value, and instruct the current loop to adjust the current loop according to the excitation current set value and the torque current set value.

[0104] Regarding the apparatus in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0105] The above device can be integrated into the controller of the motor, and the controller can realize the corresponding functions.

[0106] Embodiments of the present disclosure provide a closed-loop field-weakening regulation method and apparatus for a permanent magnet synchronous motor. These methods obtain the voltage deviation between the motor voltage and the maximum output voltage, then determine the gain coefficient corresponding to the voltage deviation. The excitation current is then derived based on the voltage deviation and the gain coefficient. The excitation current is then derived by determining the gain system employed based on the voltage deviation in the current operating state. This achieves an accurate and effective excitation current generation mechanism, resolving the issue of motor current oscillation caused by voltage reduction.

[0107] The technical solution provided by the present disclosure will rapidly increase when the voltage output is saturated during the acceleration process. To prevent the current from being out of control; when reaching the steady state, even if the voltage is not saturated, it will not decrease instantly , to avoid the difference between it and the speed loop output The mutual collision causes drastic changes in the two, thereby avoiding phenomena such as severe torque fluctuations.

[0108] Other embodiments of the present invention will readily occur to those skilled in the art after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

[0109] It should be understood that the present invention is not limited to the exact construction described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for regulating the weakening magnetic field of a permanent magnet synchronous motor, characterized in that: include: Get the voltage deviation between the motor voltage and the maximum output voltage; Obtaining a gain coefficient corresponding to the voltage deviation; Obtaining an excitation current according to the voltage deviation and the gain coefficient; The step of obtaining the gain coefficient corresponding to the voltage deviation includes: Obtaining a gain coefficient that matches the voltage deviation from preset integral gain configuration data, wherein the gain configuration data includes a correspondence between multiple sets of voltage deviation values ​​and gain coefficients; Wherein, when the voltage deviation is ≥ 0, the gain coefficient decreases as the voltage deviation increases. When the voltage deviation is less than 0, the gain coefficient increases as the absolute value of the voltage deviation increases.

2. The permanent magnet synchronous motor weak magnetic closed-loop regulation method according to claim 1, characterized in that: The step of obtaining a voltage deviation between the motor voltage and the maximum output voltage comprises: The motor voltage is obtained by calculating the direct-axis voltage and the quadrature-axis voltage; Calculating the maximum output voltage according to the bus voltage; Calculate the voltage deviation: Voltage deviation = maximum output voltage - motor voltage.

3. The permanent magnet synchronous motor weak magnetic closed-loop regulation method according to claim 1, characterized in that: The method further comprises: The excitation current and torque current are limited according to the current maximum motor current, an excitation current given value and a torque current given value are obtained, and the current loop is instructed to perform current loop adjustment according to the excitation current given value and the torque current given value.

4. The permanent magnet synchronous motor weak magnetic closed-loop regulation method according to claim 3, characterized in that: The step of performing amplitude limiting processing on the excitation current and the torque current to obtain a given value of the excitation current and the torque current comprises: According to the preset motor speed and maximum motor current correspondence curve, the maximum motor current corresponding to the current motor speed is obtained; When the following expressions are met, the torque current and / or the excitation current are reduced to obtain the torque current given value and / or the excitation current given value:

5. The permanent magnet synchronous motor weak magnetic closed-loop regulation method according to claim 1, characterized in that: The gain coefficient is an integral gain coefficient or a proportional gain coefficient.

6. A permanent magnet synchronous motor weak magnetic closed loop regulating device, characterized in that: include: A voltage deviation acquisition module is used to obtain the voltage deviation between the motor voltage and the maximum output voltage; A gain coefficient acquisition module, used to obtain the gain coefficient corresponding to the voltage deviation; an excitation current acquisition module, configured to obtain the excitation current according to the voltage deviation and the gain coefficient; The gain coefficient acquisition module is specifically configured to acquire a gain coefficient that matches the voltage deviation from preset integral gain configuration data, wherein the gain configuration data includes a correspondence between multiple sets of voltage deviation values ​​and gain coefficients; Wherein, when the voltage deviation is ≥ 0, the gain coefficient decreases as the voltage deviation increases. When the voltage deviation is less than 0, the gain coefficient increases as the absolute value of the voltage deviation increases.

7. The permanent magnet synchronous motor weak magnetic closed-loop regulating device according to claim 6, characterized in that: The voltage deviation acquisition module includes: A motor voltage acquisition submodule, configured to calculate the motor voltage based on the direct-axis voltage and the quadrature-axis voltage; A maximum output voltage acquisition submodule, configured to calculate the maximum output voltage according to the bus voltage; The deviation calculation submodule is used to calculate the voltage deviation: Voltage deviation = maximum output voltage - motor voltage.

8. The permanent magnet synchronous motor weak magnetic closed-loop regulating device according to claim 5, characterized in that: The device further comprises: The limiting processing module is used to limit the excitation current and torque current according to the current maximum motor current, obtain the excitation current set value and the torque current set value, and instruct the current loop to adjust the current loop according to the excitation current set value and the torque current set value.

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