Motor torque determination method, vehicle and storage medium

Abstract

The invention provides a motor torque determination method, a vehicle and a storage medium, and relates to the technical field of motors. The method comprises the following steps: acquiring three-phase current of a motor; determining a direct-axis current and a quadrature-axis current based on the three-phase current; according to the direct-axis current, the quadrature-axis current, and a pre-stored flux linkage mapping table and a quadrature-direct-axis inductance mapping table, determining a flux linkage value and a quadrature-direct-axis inductance difference; wherein the flux linkage mapping table is constructed based on flux linkage values corresponding to different quadrature-axis currents and direct-axis currents, and the quadrature-direct-axis inductance mapping table is constructed based on quadrature-direct-axis inductance differences corresponding to different quadrature-axis currents and direct-axis currents; and the output torque of the motor is determined based on the direct-axis current, the quadrature-axis current, the flux linkage value and the quadrature-direct-axis inductance difference, so that the output torque of the motor can be accurately determined.

Description

Technical Field

[0001] This application relates to the field of motor technology, and in particular to a method for determining motor torque, a vehicle, and a storage medium. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs), as a type of AC motor, are widely used in pure electric and hybrid vehicles due to their advantages such as high power density, high efficiency, and large torque-to-current ratio.

[0003] In related technologies, in new energy vehicles driven by permanent magnet synchronous motors, the cost of using torque sensors is very high, and since there is a relatively direct functional relationship between output current and output torque, the output torque of the motor is often directly estimated by monitoring the current parameters.

[0004] However, directly calculating the motor's output torque by monitoring current parameters often ignores the influence of temperature on the motor's output torque, resulting in low accuracy of the calculated motor output torque, which is not conducive to motor control. Summary of the Invention

[0005] This application provides a method for determining motor torque, a vehicle, and a storage medium to address the problem of low accuracy in estimating the output torque of current motors.

[0006] In a first aspect, embodiments of this application provide a method for determining motor torque, including: Obtain the three-phase current of the motor; Based on the three-phase currents, determine the direct-axis current and the quadrature-axis current; The flux linkage value and the difference between the quadrature and direct axes inductance are determined based on the direct-axis current, the quadrature-axis current, and the pre-stored flux linkage mapping table and quadrature-direct-axis inductance mapping table; wherein, the flux linkage mapping table is constructed based on the flux linkage values ​​corresponding to different quadrature-axis currents and direct-axis currents, and the quadrature-direct-axis inductance mapping table is constructed based on the difference between the quadrature-axis currents and direct-axis currents; The output torque of the motor is determined based on the direct-axis current, the quadrature-axis current, the flux linkage value, and the difference between the direct and quadrature-axis inductances.

[0007] Based on the above technical content, this embodiment of the application, by pre-storing flux linkage mapping tables and quadrature-direct axis inductance mapping tables constructed according to different quadrature-axis currents and direct-axis currents, after determining the direct-axis current and quadrature-axis current under the current operating condition, eliminates the need for complex calculations. It can quickly and accurately determine the flux linkage value and the difference between the quadrature-direct axis inductance under the current operating condition simply by using the flux linkage mapping tables and the quadrature-direct axis inductance mapping tables. After determining the flux linkage value and the difference between the quadrature-direct axis inductance, the motor's output torque can be accurately determined using the direct-axis current, quadrature-axis current, flux linkage value, and the difference between the quadrature-direct axis inductance. This allows for real-time estimation of the motor's output torque, with more accurate estimation results, providing a parameter basis and data support for the precise execution of subsequent motor control strategies.

[0008] In one possible implementation, before determining the flux linkage value and the difference between the direct and quadrature axis inductances based on the direct-axis current, the quadrature axis current, and pre-stored flux linkage mapping tables and quadrature-direct-axis inductance mapping tables, the method further includes: A dataset was obtained based on the actual output torque of the motor under different direct-axis and quadrature-axis currents. From the dataset, obtain the quadrature axis current and actual output torque of the motor when the direct axis current is a preset value; Based on the quadrature axis current and actual output torque of the motor when the direct axis current is the preset value, determine the flux linkage scatter plot data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value; Based on the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, the flux linkage mapping table is constructed.

[0009] In this embodiment, considering that dynamic changes in operating conditions can lead to changes in flux linkage, a dataset needs to be obtained based on different quadrature-axis and direct-axis currents before determining the flux linkage value. Then, based on the motor's quadrature-axis current and actual output torque when the direct-axis current is a preset value, scatter plot data of flux linkage corresponding to different quadrature-axis currents of the motor when the direct-axis current is a preset value is obtained. Finally, a flux linkage mapping table can be constructed based on the obtained scatter plot data.

[0010] In one possible implementation, constructing the flux linkage mapping table based on the flux linkage scatter data corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value includes: Based on the flux linkage scatter plot data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, determine the flux linkage scatter plot data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value; Based on the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, and the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value, the flux linkage mapping table is constructed.

[0011] Here, considering that the direct-axis current includes both preset and non-preset values, it is necessary to first determine the flux linkage scatter plot data corresponding to different quadrature-axis currents when the direct-axis current is not a preset value, based on the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is a preset value. Then, based on the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is a preset value, and the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is not a preset value, a flux linkage mapping table can be constructed. This flux linkage mapping table can comprehensively cover the full range of combinations of direct-axis and quadrature-axis currents during motor operation.

[0012] In one possible implementation, determining the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value, based on the quadrature-axis current and actual output torque of the motor when the direct-axis current is the preset value, includes: Based on the quadrature axis current and actual output torque of the motor when the direct axis current is the preset value, and the current torque estimation formula, the flux linkage values ​​corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value are determined. Data processing is performed on the flux linkage values ​​corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, to obtain scatter plot data of flux linkage corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value; wherein, the data processing includes deleting abnormal data and interpolation processing.

[0013] Here, after obtaining the quadrature-axis current and actual output torque of the motor when the direct-axis current is at a preset value, the flux linkage values ​​corresponding to different quadrature-axis currents of the motor when the direct-axis current is at a preset value can be calculated using the current-torque estimation formula. To avoid the influence of abnormal data on subsequent calculations, it is also necessary to delete abnormal data and perform interpolation processing on the obtained data, thereby obtaining scatter plot data of flux linkage corresponding to different quadrature-axis currents of the motor when the direct-axis current is at a preset value. This improves the accuracy and completeness of the data, thus laying a reliable foundation for the expansion of the flux linkage mapping table under the condition that the direct-axis current is not at a preset value.

[0014] In one possible implementation, determining the flux linkage scatter data corresponding to different quadrature-axis currents of the motor when the direct-axis current is not the preset value, based on the flux linkage scatter data corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value, includes: Based on the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, the flux linkage values ​​corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value are assigned values. Based on the result of the assignment process, the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value are determined.

[0015] In this embodiment of the application, in order to more comprehensively cover the full range of operating conditions of direct-axis current and quadrature-axis current during motor operation, it is also necessary to assign values ​​to the flux linkage values ​​corresponding to different quadrature-axis currents of the motor when the direct-axis current is a preset value, based on the flux linkage scatter data corresponding to different quadrature-axis currents of the motor when the direct-axis current is a preset value. This process ensures the integrity of the data.

[0016] In one possible implementation, constructing the flux linkage mapping table based on the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value, and the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is not the preset value, includes: Interpolation processing is performed on the flux linkage scatter plot data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, and on the flux linkage scatter plot data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value. Based on the interpolation results, magnetic flux mesh data is generated; Based on the magnetic flux linkage mesh data, construct the magnetic flux linkage mapping table.

[0017] Here, the obtained flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is at a preset value, and the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is not at a preset value, are incomplete. In order to comprehensively cover the full range of combinations of direct-axis and quadrature-axis currents during motor operation, interpolation processing is required to generate flux linkage mesh data. Finally, based on the flux linkage mesh data, a flux linkage mapping table is constructed to ensure its completeness.

[0018] In one possible implementation, before determining the flux linkage value and the difference between the direct and quadrature axis inductances based on the direct-axis current, the quadrature axis current, and pre-stored flux linkage mapping tables and quadrature-direct-axis inductance mapping tables, the method further includes: Based on the dataset and the flux linkage mapping table, determine the quadrature-direct axis inductance difference corresponding to different quadrature-axis currents and direct-axis currents; Based on the difference in quadrature-axis and direct-axis inductances corresponding to different quadrature-axis and direct-axis currents, the quadrature-axis and direct-axis inductance mapping table is constructed.

[0019] In this embodiment, considering that dynamic changes in operating conditions can lead to variations in the quadrature-axis and direct-axis inductance difference, it is necessary to determine the quadrature-axis and direct-axis inductance differences corresponding to different quadrature-axis and direct-axis currents based on the dataset and flux linkage mapping table before determining the motor's output torque. Finally, a quadrature-axis and direct-axis inductance mapping table is constructed based on the obtained quadrature-axis and direct-axis inductance differences. Therefore, when it is necessary to determine the quadrature-axis and direct-axis inductance difference under the current operating conditions, it can be obtained quickly and accurately simply by consulting the quadrature-axis and direct-axis inductance mapping table.

[0020] In one possible implementation, determining the quadrature-axis and direct-axis inductance differences corresponding to different quadrature-axis and direct-axis currents based on the dataset and the flux linkage mapping table includes: Based on the dataset and the flux linkage mapping table, determine the flux linkage values ​​and the actual output torque of the motor corresponding to different quadrature-axis currents and direct-axis currents; Based on the flux linkage values ​​corresponding to the different quadrature-axis currents and direct-axis currents, the actual output torque of the motor, and the current-torque estimation formula, the difference between quadrature-axis and direct-axis inductances under different quadrature-axis and direct-axis currents is determined.

[0021] Here, based on the dataset and flux linkage mapping table, the flux linkage values ​​and the actual output torque of the motor corresponding to different quadrature-axis and direct-axis currents can be obtained. Then, according to the current-torque estimation formula, the difference between quadrature-axis and direct-axis inductances under different quadrature-axis and direct-axis currents can be accurately determined.

[0022] Secondly, embodiments of this application provide a device for determining motor torque, comprising: The acquisition module is used to acquire the three-phase current of the motor; The first determining module is used to determine the direct-axis current and the quadrature-axis current based on the three-phase current; The second determining module is used to determine the flux linkage value and the difference between the quadrature and direct axes inductance based on the direct-axis current, the quadrature-axis current, and a pre-stored flux linkage mapping table and a quadrature-direct-axis inductance mapping table; wherein, the flux linkage mapping table is constructed based on the flux linkage values ​​corresponding to different quadrature-axis currents and direct-axis currents, and the quadrature-direct-axis inductance mapping table is constructed based on the difference between the quadrature-direct-axis inductances corresponding to different quadrature-axis currents and direct-axis currents; The third determining module is used to determine the output torque of the motor based on the direct-axis current, the quadrature-axis current, the flux linkage value, and the difference between the direct and quadrature-axis inductances.

[0023] In one possible implementation, the second determining module is used to obtain a dataset based on the actual output torque of the motor at different direct-axis and quadrature-axis currents; From the dataset, obtain the quadrature axis current and actual output torque of the motor when the direct axis current is a preset value; Based on the quadrature axis current and actual output torque of the motor when the direct axis current is the preset value, determine the flux linkage scatter plot data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value; Based on the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, the flux linkage mapping table is constructed.

[0024] In one possible implementation, the second determining module is used to determine the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value, based on the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value. Based on the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, and the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value, the flux linkage mapping table is constructed.

[0025] In one possible implementation, the second determining module is used to determine the flux linkage value corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, based on the quadrature axis current and actual output torque of the motor when the direct axis current is the preset value, and the current torque estimation formula. Data processing is performed on the flux linkage values ​​corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, to obtain scatter plot data of flux linkage corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value; wherein, the data processing includes deleting abnormal data and interpolation processing.

[0026] In one possible implementation, the second determining module is used to assign values ​​to the flux linkage values ​​corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value, based on the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value. Based on the result of the assignment process, the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value are determined.

[0027] In one possible implementation, the second determining module is used to perform interpolation processing on the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, and the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value. Based on the interpolation results, magnetic flux mesh data is generated; Based on the magnetic flux linkage mesh data, construct the magnetic flux linkage mapping table.

[0028] In one possible implementation, the second determining module is used to determine the difference between quadrature-axis and direct-axis inductances corresponding to different quadrature-axis currents and direct-axis currents based on the dataset and the flux linkage mapping table. Based on the difference in quadrature-axis and direct-axis inductances corresponding to different quadrature-axis and direct-axis currents, the quadrature-axis and direct-axis inductance mapping table is constructed.

[0029] In one possible implementation, the second determining module is used to determine the flux linkage values ​​and the actual output torque of the motor corresponding to different quadrature-axis currents and direct-axis currents based on the dataset and the flux linkage mapping table. Based on the flux linkage values ​​corresponding to the different quadrature-axis currents and direct-axis currents, the actual output torque of the motor, and the current-torque estimation formula, the difference between quadrature-axis and direct-axis inductances under different quadrature-axis and direct-axis currents is determined.

[0030] Thirdly, embodiments of this application provide a vehicle including a memory and a processor. The memory stores a computer program that can run on the processor. When the processor executes the computer program, it implements the method for determining motor torque as described in any of the first aspects.

[0031] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method for determining motor torque as described in any of the first aspects.

[0032] It is understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.

[0033] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this specification. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of an application scenario provided by an embodiment of this application; Figure 2 This is a flowchart illustrating a method for determining motor torque according to an embodiment of this application; Figure 3 This is a flowchart illustrating a method for determining motor torque according to another embodiment of this application; Figure 4 This is a graph showing the flux linkage values ​​corresponding to different quadrature axis currents of a motor when the direct axis current is 0, provided in one embodiment of this application. Figure 5 Yes Figure 4The flux linkage value graph after processing the flux linkage value in the image; Figure 6 It is based on Figure 5 A scatter plot of flux linkage data corresponding to the direct-axis and quadrature-axis currents determined by the flux linkage values ​​in the graph. Figure 7 It is based on Figure 6 The magnetic flux mapping table generated from the magnetic flux scatter data; Figure 8 This is a schematic diagram of the structure of a motor torque determination device provided in an embodiment of this application; Figure 9 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application; Detailed Implementation The present application will be described more clearly below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the function of the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application. These all fall within the protection scope of the present application.

[0036] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0037] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0038] In the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0039] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0040] Furthermore, the term "multiple" mentioned in the embodiments of this application should be interpreted as two or more.

[0041] First, the terms used in the embodiments of this application will be explained: Permanent magnet synchronous motors (PMSMs) are the core power actuators in electric vehicles, undertaking the core functions of energy conversion and power transmission. Their core principle is electromagnetic induction and magnetic field coupling. They utilize the interaction between the constant magnetic field generated by permanent magnets and the rotating magnetic field generated by three-phase alternating current flowing through the stator windings to achieve bidirectional conversion between mechanical and electrical energy. When the stator rotating magnetic field rotates at synchronous speed, an electromagnetic attraction / repulsion force, i.e., electromagnetic torque, is generated between the constant magnetic field of the rotor permanent magnets and the stator rotating magnetic field. Because the rotational speed of the stator rotating magnetic field is strictly synchronized with the rotor's mechanical speed, the rotor rotates uniformly following the rotating magnetic field under the drive of the electromagnetic torque, thereby transmitting mechanical energy to the vehicle's drive system through the output shaft.

[0042] Magnetic flux linkage: This represents the product of the total magnetic flux passing through the conductive coil and the number of turns in the winding. It directly determines the electromagnetic torque, induced electromotive force, and control characteristics of the motor. Magnetic flux linkage is one of the core control objectives of PMSM control; its magnitude and direction directly determine the motor's operating state.

[0043] The formula for calculating the torque of a permanent magnet synchronous motor is: Te= 1.5*P*[ψ*Iq+(Ld-Lq)*Id*Iq]; Where Te is the motor torque, P is the number of motor pole pairs, ψ is the resultant flux linkage, Iq is the Q-axis current (also known as quadrature axis current), Id is the D-axis current (also known as direct axis current), Ld is the D-axis inductance (also known as direct axis inductance), Lq is the Q-axis inductance (also known as quadrature axis inductance), and Ld-Lq is the difference between quadrature and direct axis inductance.

[0044] In the vector control of a permanent magnet synchronous motor, Id and Iq are two orthogonal components of the three-phase stator current in the rotor synchronous rotating coordinate system after coordinate transformation. Their core function is to separate the magnetic field regulation and torque output functions, achieving precise control of the motor's torque and speed. The rotor synchronous rotating coordinate system is a coordinate system that rotates synchronously with the rotor, and its coordinate axes are bound to the magnetic field direction of the rotor's permanent magnets. The direct axis (d-axis) is aligned with the direction of the rotor's permanent magnet's main magnetic field, and its core function is to adjust the air gap magnetic field strength. The quadrature axis (q-axis) is perpendicular to the direction of the rotor's permanent magnet's main magnetic field, and its core function is to generate electromagnetic torque.

[0045] Id is the current component flowing along the d-axis. Its core function is to change the strength of the combined magnetic field in the motor's air gap, essentially acting as a magnetic field regulating switch. When Id = 0, the stator current does not affect the rotor's permanent magnet magnetic field, and the air gap magnetic field is provided solely by the rotor's permanent magnets. Iq is the current component flowing along the q-axis. Its core function is to generate the electromagnetic torque that drives the rotor's rotation, serving as the core power source for torque output.

[0046] Current calculation methods typically treat flux linkage, Ld, and Lq as constants. However, as the motor operates continuously, its internal temperature changes, causing variations in flux linkage and the difference between the direct and quadrature axis inductances. If these parameters are always treated as constants, the impact of these variations on torque estimation is ignored, leading to a decrease in the accuracy of motor output torque estimation.

[0047] In the field of functional safety of main drive motors, high-precision output estimation is a prerequisite for the correct implementation of torque monitoring. If the accuracy of output torque estimation is low, the following consequences may occur: torque monitoring errors may lead to shutdowns due to false alarms, and torque monitoring may fail to identify unexpected torque, resulting in safety risks.

[0048] Furthermore, due to the complex structure of temperature measuring equipment components, adding temperature measuring components would require significant modifications to the motor structure, potentially causing the motor to malfunction. Therefore, in the field of functional safety, temperature signals cannot be used to estimate the actual output torque for functional safety purposes due to cost and the need for compact integrated structures. While the internal temperature of a permanent magnet synchronous motor constantly changes during operation, and temperature affects the flux linkage and the difference between the direct and quadrature axes inductance, even when the motor meets functional safety requirements, the inability to acquire temperature signals makes it impossible to accurately determine the quantification of the temperature-induced impact on the flux linkage and the difference between the direct and quadrature axes inductance.

[0049] To address the aforementioned issues, this application proposes a method for determining motor torque. This method, after obtaining the three-phase currents of the motor, can determine the direct-axis current and quadrature-axis current based on these currents. By pre-storing flux linkage mapping tables and quadrature-direct-axis inductance mapping tables constructed based on different quadrature-axis and direct-axis currents, once the direct-axis and quadrature-axis currents are determined, no complex calculations are required. The flux linkage value and the difference between the quadrature-direct-axis and quadrature-axis inductances under the current operating condition can be quickly and accurately determined simply by using these tables. This avoids estimation errors in electromagnetic parameters caused by dynamic changes in operating conditions. After determining the flux linkage value and the difference between the quadrature-direct-axis and quadrature-axis inductances, the motor's output torque can be accurately determined using the direct-axis current, quadrature-axis current, flux linkage value, and the difference between the quadrature-direct-axis and quadrature-axis inductances. This allows for real-time estimation of the motor's output torque, with more accurate estimation results, providing a parameter basis and data support for the precise execution of subsequent motor control strategies.

[0050] First refer to Figure 1 , Figure 1The diagram illustrates an application scenario according to an embodiment of this application, involving devices including a current sensor 101 and a vehicle control system 102. After the vehicle control system 102 receives the three-phase current of the motor from the current sensor 101, it first performs Clark and Park transformations on the obtained three-phase currents to obtain the direct-axis current and quadrature-axis current. Then, based on the motor's inherent parameters—number of pole pairs, flux linkage, quadrature-axis inductance, direct-axis inductance—and the current-torque estimation formula, it determines the motor's output torque. However, the motor is affected by various factors during operation, such as temperature. In the field of functional safety, temperature signals cannot be collected due to cost and compact integrated structures. Furthermore, the internal temperature of a permanent magnet synchronous motor changes continuously during operation, causing variations in flux linkage and the difference between direct and quadrature-axis inductances. If the flux linkage and the difference between direct and quadrature-axis inductances are always calculated as constants, the accuracy of the estimated motor torque will be affected.

[0051] In this embodiment, considering the influence of different operating conditions on the flux linkage and the difference between the direct and quadrature axis inductances, a flux linkage mapping table and a quadrature axis inductance mapping table are constructed based on different quadrature axis currents and direct axis currents. Thus, the vehicle control system 102 can select the flux linkage value and the difference between the direct and quadrature axis inductances under the current operating conditions, thereby accurately driving the motor's output torque.

[0052] In this embodiment, the vehicle control system 102 is primarily responsible for integrating sensor data, running algorithms, and decision control. The controller of the vehicle control system 102 can acquire the three-phase current fed back by the current sensor 101 in the vehicle, and analyzes and processes the acquired three-phase current according to a preset program and algorithm to obtain the direct-axis current and quadrature-axis current. After obtaining the direct-axis current and quadrature-axis current, the system determines the flux linkage value and the difference between the direct and quadrature-axis inductances based on the pre-stored flux linkage mapping table and quadrature-direct-axis inductance mapping table in the vehicle control system 102. Finally, the output torque of the motor is determined based on the direct-axis current, quadrature-axis current, flux linkage value, and the difference between the direct and quadrature-axis inductances. This allows for real-time estimation of the motor's output torque, with more accurate estimation results, providing a parameter basis and data support for the precise execution of subsequent motor control strategies.

[0053] For example, the controller of the vehicle control system 102 can be implemented as an Electronic Control Unit (ECU) on the vehicle. The ECU can acquire the three-phase current fed back by the current sensor during motor operation, and analyze and process the acquired data according to a preset program and algorithm to obtain the direct-axis current and quadrature-axis current. Based on the obtained direct-axis current and quadrature-axis current, the output torque of the motor is determined.

[0054] The following is combined Figure 1 Application scenarios, refer to Figures 2-4This application describes a method for determining motor torque according to exemplary embodiments thereof. It should be noted that the above application scenarios are shown only to facilitate understanding of the spirit and principles of this application, and the embodiments of this application are not limited in any way. Rather, the embodiments of this application can be applied to any applicable scenario.

[0055] refer to Figure 2 , Figure 2 This is a schematic flowchart illustrating a method for determining motor torque according to an embodiment of this application. Figure 2 As shown, the method in the embodiments of this application may include: Step 201: Obtain the three-phase current of the motor.

[0056] In this embodiment, the three-phase current of the motor can be determined by feedback from the current sensor, provided that the motor meets functional safety requirements.

[0057] Step 202: Determine the direct-axis current and quadrature-axis current based on the three-phase current.

[0058] After obtaining the three-phase current, the three-phase current can be converted into direct-axis current Id and quadrature-axis current Iq by performing Clarke transformation and Park transformation respectively.

[0059] Here, Id is the current component flowing along the d-axis, and its core function is to change the strength of the combined magnetic field in the motor's air gap, essentially acting as a magnetic field regulating switch. When Id = 0, the stator current does not affect the rotor's permanent magnet magnetic field, and the air gap magnetic field is provided solely by the rotor's permanent magnets. Iq is the current component flowing along the q-axis, and its core function is to generate the electromagnetic torque that drives the rotor's rotation; it is the core power source for torque output.

[0060] Step 203: Determine the flux linkage value and the difference between the direct and quadrature axis inductances based on the direct axis current, quadrature axis current, and the pre-stored flux linkage mapping table and quadrature-direct axis inductance mapping table.

[0061] The flux linkage mapping table is constructed based on the flux linkage values ​​corresponding to different quadrature-axis currents and direct-axis currents, while the quadrature-direct-axis inductance mapping table is constructed based on the difference between the quadrature-axis and direct-axis inductances corresponding to different quadrature-axis currents and direct-axis currents.

[0062] In some embodiments, the flux linkage value can be determined first based on a direct-axis current, quadrature-axis current, and flux linkage mapping table.

[0063] Then, the difference between the direct-axis and quadrature-axis inductances is determined according to the mapping table of direct-axis current, quadrature-axis current, and direct-axis and quadrature-axis inductances.

[0064] Step 204: Determine the motor's output torque based on the direct-axis current, quadrature-axis current, flux linkage value, and the difference between the direct and quadrature-axis inductances.

[0065] Once the direct-axis current, quadrature-axis current, flux linkage value, and the difference between the direct and quadrature-axis inductances are determined, the output torque of the motor can be determined using the current-torque estimation formula.

[0066] The formula for the output torque of the motor is: Te=1.5*P*[ψ*Iq+(Ld-Lq)*Id*Iq]; Where Te is the output torque of the motor, P is the number of pole pairs of the motor, ψ is the resultant flux linkage, Iq is the Q-axis current (also known as quadrature axis current), Id is the D-axis current (also known as direct axis current), Ld is the D-axis inductance (also known as direct axis inductance), Lq is the Q-axis inductance (also known as quadrature axis inductance), and Ld-Lq is the difference between the quadrature and direct axis inductances.

[0067] In this embodiment, by pre-storing flux linkage mapping tables and quadrature-direct-axis inductance mapping tables constructed based on different quadrature-axis and direct-axis currents, once the direct-axis and quadrature-axis currents under the current operating condition are determined, no complex calculations are required. The flux linkage value and the difference between the quadrature-direct-axis and direct-axis inductances under the current operating condition can be quickly and accurately determined simply by using these tables. After determining the flux linkage value and the difference between the quadrature-direct-axis and direct-axis inductances, the motor's output torque can be accurately determined using the direct-axis current, quadrature-axis current, flux linkage value, and the difference between the quadrature-direct-axis and direct-axis inductances. This allows for real-time estimation of the motor's output torque, with more accurate estimation results, providing a parameter basis and data support for the precise execution of subsequent motor control strategies.

[0068] In addition, in determining the flux linkage mapping table, this application embodiment considers that the influence of the cross-coupling effect between the direct axis current and the quadrature axis current varies significantly when the direct axis current is at different values. The correspondence between flux linkage and quadrature axis current will exhibit different nonlinear characteristics. Therefore, it is necessary to determine the flux linkage corresponding to different quadrature axis currents of the motor when the direct axis current is a preset value, and the flux linkage corresponding to different quadrature axis currents of the motor when the direct axis current is not a preset value, so as to form a complete flux linkage mapping table. Figure 3 A flowchart illustrating a method for determining motor torque according to another embodiment of this application is shown below. Figure 3 As shown, the method includes: Step 301: Obtain the three-phase current of the motor.

[0069] In this embodiment, the current sensor will feed back the acquired three-phase current to the vehicle control system.

[0070] Step 302: Determine the direct-axis current and quadrature-axis current based on the three-phase current.

[0071] After obtaining the three-phase current, the three-phase current can be converted into direct-axis current Id and quadrature-axis current Iq by performing Clarke transformation and Park transformation respectively.

[0072] Here, the implementation method of step 302 can be found in [reference needed]. Figure 2 The relevant descriptions in the embodiments will not be repeated here.

[0073] Step 303: Construct the flux linkage mapping table and the quadrature-direct axis inductance mapping table.

[0074] In some embodiments, a dataset can first be obtained based on the actual output torque of the motor at different direct-axis and quadrature-axis currents. Then, from the dataset, the quadrature-axis current and actual output torque of the motor when the direct-axis current is a preset value are obtained. Next, based on the quadrature-axis current and actual output torque of the motor when the direct-axis current is a preset value, flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is a preset value are determined. Finally, based on the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is a preset value, a flux linkage mapping table is constructed.

[0075] In this embodiment, a dataset is constructed based on the actual output torque of the motor under different direct-axis and quadrature-axis currents, which can be carried out during the bench test phase.

[0076] For example, during the bench test phase, Id and Iq can be given in 20A increments from 0A to 0.8*Ismax, and the actual output torque can be collected using a dynamometer. Here, Ismax is the maximum three-phase current.

[0077] In this embodiment, after constructing a dataset through bench testing, the quadrature-axis current and actual output torque of the motor when the direct-axis current is at a preset value can be obtained from the dataset. Then, based on the quadrature-axis current and actual output torque of the motor when the direct-axis current is at the preset value, and the current-torque estimation formula, the flux linkage values ​​corresponding to different quadrature-axis currents of the motor when the direct-axis current is at the preset value are determined. Finally, during the dataset construction process, to ensure data consistency and reliability, after obtaining the flux linkage values ​​corresponding to different quadrature-axis currents of the motor when the direct-axis current is at the preset value, data processing is required to obtain scatter plot data of flux linkage corresponding to different quadrature-axis currents of the motor when the direct-axis current is at the preset value. This data processing may include deleting abnormal data and interpolation.

[0078] For example, the preset value of the direct-axis current can be 0. The Iq value when Id equals 0, along with the corresponding actual output torque, can be directly obtained from the dataset.

[0079] For example, after obtaining the flux linkage values ​​corresponding to different quadrature-axis currents of the motor when the direct-axis current is 0, a plot can be drawn based on these flux linkage values, such as... Figure 4 As shown. From Figure 4As can be seen, there are obvious outliers in the data. After deleting the outlier data and replacing them with null values, we need to use interpolation to obtain the data from the outliers to replace the null values, resulting in the following: Figure 5 The data graph shown allows the processed magnetic flux two-dimensional data curve to be as smooth as possible when Id=0.

[0080] In some embodiments, such as Figure 6 As shown, after determining the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is a preset value, the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is not a preset value can be determined based on this data. Then, a flux linkage mapping table is constructed based on the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is a preset value and the data corresponding to different quadrature-axis currents of the motor when the direct-axis current is not a preset value.

[0081] In this embodiment, firstly, based on the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is a preset value, the flux linkage values ​​corresponding to different quadrature-axis currents of the motor when the direct-axis current is not a preset value are assigned values. Then, based on the result of the assignment process, the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is not a preset value are determined.

[0082] Specifically, when the direct-axis current is not a preset value, the flux linkage values ​​corresponding to different quadrature-axis currents of the motor can be assigned using interpolation, model fitting, or neighboring value assignment methods.

[0083] For example, interpolation methods can include linear interpolation, bilinear interpolation, cubic spline interpolation, and triangular interpolation. Linear interpolation is suitable for situations where the direct-axis current intervals are small. Bilinear interpolation is suitable for two-dimensional matrix tables, where the direct-axis current is in rows and the quadrature-axis current is in columns. Cubic spline interpolation is suitable for scenarios involving large direct-axis current field weakening and large quadrature-axis current heavy loads. Triangular interpolation is suitable for boundary conditions involving deep field weakening and speed enhancement of the motor, and is an optimized supplement to bilinear interpolation.

[0084] For example, model fitting assignment methods can include polynomial fitting assignment methods and magnetic circuit model fitting assignment methods. The polynomial fitting assignment method performs high-order polynomial fitting on the flux linkage data corresponding to different direct-axis currents for each quadrature-axis current, obtaining a fitting formula for the flux linkage with respect to the direct-axis current. Substituting the non-preset direct-axis current into the fitting formula allows for the calculation of the flux linkage value. The magnetic circuit model fitting assignment method uses a flux linkage model fitted by finite element simulation. The flux linkage data of the known direct-axis current is substituted into the model correction parameters, and then the corrected model is used to calculate the flux linkage value for non-preset direct-axis currents.

[0085] In this embodiment, after determining the flux linkage scatter plot data corresponding to different quadrature axis currents of the motor when the direct axis current is a preset value, and the flux linkage scatter plot data corresponding to different quadrature axis currents of the motor when the direct axis current is not a preset value, the flux linkage scatter plot data corresponding to different quadrature axis currents of the motor when the direct axis current is a preset value, and the flux linkage scatter plot data corresponding to different quadrature axis currents of the motor when the direct axis current is not a preset value, can be interpolated using the griddata function to draw a grid and obtain the flux linkage values ​​of the full map range of Id and Iq, which is the flux linkage mapping table.

[0086] Specifically, firstly, interpolation processing can be performed on the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is at a preset value, and on the flux linkage scatter plot data corresponding to different quadrature-axis currents of the motor when the direct-axis current is not at a preset value. Then, flux linkage mesh data is generated based on the interpolation results. Finally, a flux linkage mapping table is constructed based on the flux linkage mesh data.

[0087] The griddata function interpolates the discrete scatter data of direct-axis current (Id), quadrature-axis current (Iq) and corresponding flux linkage values ​​(ψ) to generate a regular grid data matrix covering the entire operating range of Id and Iq.

[0088] For example, still using the above Figure 6 Taking the magnetic flux linkage scatter data corresponding to Id and Iq in the grid as an example, according to the griddata function... Figure 6 After processing the data, the result will be as follows: Figure 7 The magnetic flux linkage mapping table is shown.

[0089] In some embodiments, the difference between quadrature-axis and direct-axis inductances corresponding to different quadrature-axis and direct-axis currents can be determined first, based on the dataset and flux linkage mapping table. Then, a quadrature-axis and direct-axis inductance mapping table can be constructed based on the difference between the quadrature-axis and direct-axis currents corresponding to different quadrature-axis and direct-axis currents.

[0090] In this embodiment, based on the data table and flux linkage mapping table, the flux linkage values ​​and the actual output torque of the motor corresponding to different quadrature-axis and direct-axis currents can be determined. Then, based on the flux linkage values ​​and the actual output torque of the motor corresponding to different quadrature-axis and direct-axis currents, as well as the current-torque estimation formula, the difference between quadrature-axis and direct-axis inductances under different quadrature-axis and direct-axis currents can be determined.

[0091] Once the flux linkage mapping table and the quadrature-direct axis inductance mapping table are determined, they can be pre-stored in the vehicle control system for use when calculating the motor's output torque.

[0092] Step 304: Determine the flux linkage value and the difference between the direct and quadrature axis inductances based on the direct axis current, quadrature axis current, and the pre-stored flux linkage mapping table and quadrature-direct axis inductance mapping table.

[0093] The flux linkage mapping table is constructed based on the flux linkage values ​​corresponding to different quadrature-axis currents and direct-axis currents, while the quadrature-direct-axis inductance mapping table is constructed based on the difference between the quadrature-axis and direct-axis inductances corresponding to different quadrature-axis currents and direct-axis currents.

[0094] Step 305: Determine the output torque of the motor based on the direct-axis current, quadrature-axis current, flux linkage value, and the difference between the direct and quadrature-axis inductances.

[0095] Here, the implementation method of steps 304-305 is described in [reference]. Figure 2 The relevant descriptions in the embodiments will not be repeated here.

[0096] In this embodiment, since the internal temperature of the motor changes continuously during operation, and temperature cannot be measured under functional safety conditions, to reduce the impact of temperature on the motor's output torque, a flux linkage mapping table and a quadrature-direct-axis inductance mapping table need to be constructed based on different quadrature-axis and direct-axis currents. These pre-constructed flux linkage and quadrature-direct-axis inductance mapping tables are then stored in the vehicle control system. When it is necessary to determine the motor's output torque, the flux linkage value and the difference between the quadrature-direct-axis and direct-axis inductances can be directly determined based on the determined direct-axis and quadrature-axis currents and the pre-stored flux linkage and quadrature-direct-axis inductance mapping tables. This improves the accuracy of the motor's output torque estimation.

[0097] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0098] Figure 8 This is a schematic diagram of the structure of a device for determining motor torque according to an embodiment of this application. Figure 5 As shown, the motor torque determination device provided in this embodiment may include: an acquisition module 801, a first determination module 802, a second determination module 803, and a third determination module 804.

[0099] The acquisition module 801 is used to acquire the three-phase current of the motor; The first determining module 802 is used to determine the direct-axis current and the quadrature-axis current based on the three-phase current; The second determining module 803 is used to determine the flux linkage value and the difference between the quadrature and direct axes inductance based on the direct-axis current, the quadrature-axis current, and a pre-stored flux linkage mapping table and a quadrature-direct-axis inductance mapping table; wherein, the flux linkage mapping table is constructed based on the flux linkage values ​​corresponding to different quadrature-axis currents and direct-axis currents, and the quadrature-direct-axis inductance mapping table is constructed based on the difference between the quadrature-direct-axis inductance corresponding to different quadrature-axis currents and direct-axis currents; The third determining module 804 is used to determine the output torque of the motor based on the direct-axis current, the quadrature-axis current, the flux linkage value, and the difference between the direct and quadrature-axis inductances.

[0100] In one possible implementation, the second determining module 803 is used to obtain a dataset based on the actual output torque of the motor at different direct-axis and quadrature-axis currents; From the dataset, obtain the quadrature axis current and actual output torque of the motor when the direct axis current is a preset value; Based on the quadrature axis current and actual output torque of the motor when the direct axis current is the preset value, determine the flux linkage scatter plot data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value; Based on the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, the flux linkage mapping table is constructed.

[0101] In one possible implementation, the second determining module 803 is used to determine the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value, based on the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value. Based on the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, and the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value, the flux linkage mapping table is constructed.

[0102] In one possible implementation, the second determining module 803 is used to determine the flux linkage value corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, based on the quadrature axis current and actual output torque of the motor when the direct axis current is the preset value, and the current torque estimation formula. Data processing is performed on the flux linkage values ​​corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, to obtain scatter plot data of flux linkage corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value; wherein, the data processing includes deleting abnormal data and interpolation processing.

[0103] In one possible implementation, the second determining module 803 is used to assign values ​​to the flux linkage values ​​corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value, based on the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value. Based on the result of the assignment process, the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value are determined.

[0104] In one possible implementation, the second determining module 803 is used to perform interpolation processing on the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value, and the flux linkage scatter data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value. Based on the interpolation results, magnetic flux mesh data is generated; Based on the magnetic flux linkage mesh data, construct the magnetic flux linkage mapping table.

[0105] In one possible implementation, the second determining module 803 is used to determine the difference between quadrature-axis and direct-axis inductances corresponding to different quadrature-axis currents and direct-axis currents based on the dataset and the flux linkage mapping table. Based on the difference in quadrature-axis and direct-axis inductances corresponding to different quadrature-axis and direct-axis currents, the quadrature-axis and direct-axis inductance mapping table is constructed.

[0106] In one possible implementation, the second determining module 803 is used to determine the flux linkage values ​​and the actual output torque of the motor corresponding to different quadrature-axis currents and direct-axis currents based on the dataset and the flux linkage mapping table. Based on the flux linkage values ​​corresponding to the different quadrature-axis currents and direct-axis currents, the actual output torque of the motor, and the current-torque estimation formula, the difference between quadrature-axis and direct-axis inductances under different quadrature-axis and direct-axis currents is determined.

[0107] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0108] Figure 9 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application. Figure 9 As shown, the vehicle 900 of this embodiment includes a processor 910 and a memory 920, wherein the memory 920 stores a computer program 921 that can run on the processor 910. When the processor 910 executes the computer program 921, it implements the steps in any of the above method embodiments, for example... Figure 2 The steps shown illustrate the method for determining the motor torque. Alternatively, when processor 910 executes computer program 921, it implements the functions of each module / unit in the above-described device embodiments, for example... Figure 8 The functions of the acquisition module 801, the first determination module 802, the second determination module 803, and the third determination module 804 are shown.

[0109] For example, computer program 921 may be divided into one or more modules / units, one or more of which are stored in memory 920 and executed by processor 910 to complete this application. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of computer program 921 in vehicle 900.

[0110] Those skilled in the art will understand that Figure 9 This is merely an example of a vehicle and does not constitute a limitation on the vehicle. It may include more or fewer components than shown, or combinations of certain components, or different components, such as input / output devices, network access devices, buses, etc.

[0111] The processor 910 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0112] The memory 920 can be an internal storage unit of the vehicle, such as a hard drive or memory, or an external storage device, such as a plug-in hard drive, smart media card (SMC), secure digital (SD) card, flash card, etc. The memory 920 can also include both internal and external storage devices. The memory 920 is used to store computer programs and other programs and data required by the vehicle. The memory 920 can also be used to temporarily store data that has been output or will be output.

[0113] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0114] An embodiment of this application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for determining motor torque.

[0115] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0116] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0117] In the embodiments provided in this application, it should be understood that the disclosed devices / vehicles and methods can be implemented in other ways. For example, the device / vehicle embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0118] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0119] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0120] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0121] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method of determining torque of an electric machine, characterized by, The method comprises: obtaining three-phase currents of the motor; determining direct-axis current and quadrature-axis current based on the three-phase currents; determining flux linkage value and direct-quadrature axis inductance difference according to the direct-axis current, the quadrature-axis current, and pre-stored flux linkage mapping table and direct-quadrature axis inductance mapping table; wherein the flux linkage mapping table is constructed based on flux linkage values corresponding to different quadrature-axis currents and direct-axis currents, and the direct-quadrature axis inductance mapping table is constructed based on direct-quadrature axis inductance differences corresponding to different quadrature-axis currents and direct-axis currents; determining output torque of the motor based on the direct-axis current, the quadrature-axis current, the flux linkage value and the direct-quadrature axis inductance difference.

2. The method of claim 1, wherein, Before the determining flux linkage value and direct-quadrature axis inductance difference according to the direct-axis current, the quadrature-axis current, and pre-stored flux linkage mapping table and direct-quadrature axis inductance mapping table, the method further comprises: obtaining a data set based on actual output torques of the motor at different direct-axis currents and quadrature-axis currents; obtaining quadrature-axis current and actual output torque of the motor when the direct-axis current is a preset value from the data set; determining flux linkage scatter point data corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value according to the quadrature-axis current and actual output torque of the motor when the direct-axis current is the preset value; constructing the flux linkage mapping table based on the flux linkage scatter point data corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value.

3. The method of claim 2, wherein The constructing the flux linkage mapping table based on the flux linkage scatter point data corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value comprises: determining flux linkage scatter point data corresponding to different quadrature-axis currents of the motor when the direct-axis current is not the preset value according to the flux linkage scatter point data corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value; constructing the flux linkage mapping table based on the flux linkage scatter point data corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value and the flux linkage scatter point data corresponding to different quadrature-axis currents of the motor when the direct-axis current is not the preset value.

4. The method of claim 2, wherein The determining flux linkage scatter point data corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value according to the quadrature-axis current and actual output torque of the motor when the direct-axis current is the preset value comprises: determining flux linkage values corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value based on the quadrature-axis current and actual output torque of the motor when the direct-axis current is the preset value and a current torque estimation formula; performing data processing on the flux linkage values corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value to obtain the flux linkage scatter point data corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value; wherein the data processing comprises deleting abnormal data and interpolation processing.

5. The method of claim 3, wherein, The determining flux linkage scatter point data corresponding to different quadrature-axis currents of the motor when the direct-axis current is not the preset value according to the flux linkage scatter point data corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value comprises: performing assignment processing on flux linkage values corresponding to different quadrature-axis currents of the motor when the direct-axis current is not the preset value according to the flux linkage scatter point data corresponding to different quadrature-axis currents of the motor when the direct-axis current is the preset value. Based on the result of the assignment processing, the flux linkage scatter point data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value is determined.

6. The method of claim 3, wherein, The flux linkage scatter point data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value and the flux linkage scatter point data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value are used to construct the flux linkage mapping table, including: Interpolation processing is performed on the flux linkage scatter point data corresponding to different quadrature axis currents of the motor when the direct axis current is the preset value and the flux linkage scatter point data corresponding to different quadrature axis currents of the motor when the direct axis current is not the preset value. Based on the result of the interpolation processing, the flux linkage grid data is generated. According to the flux linkage grid data, the flux linkage mapping table is constructed.

7. The method of claim 2 to 6, wherein Before the flux linkage value and the difference between the direct axis inductance and the quadrature axis inductance are determined according to the direct axis current, the quadrature axis current, and the pre-stored flux linkage mapping table and the direct-quadrature axis inductance mapping table, the method further includes: Based on the data set and the flux linkage mapping table, the difference between the direct axis inductance and the quadrature axis inductance corresponding to different quadrature axis currents and direct axis currents is determined. According to the difference between the direct axis inductance and the quadrature axis inductance corresponding to different quadrature axis currents and direct axis currents, the direct-quadrature axis inductance mapping table is constructed.

8. The method of claim 7, wherein, The difference between the direct axis inductance and the quadrature axis inductance corresponding to different quadrature axis currents and direct axis currents is determined based on the data set and the flux linkage mapping table, including: Based on the data set and the flux linkage mapping table, the flux linkage value and the actual output torque of the motor corresponding to different quadrature axis currents and direct axis currents are determined. Based on the flux linkage value and the actual output torque of the motor corresponding to different quadrature axis currents and direct axis currents, and the current torque estimation formula, the difference between the direct axis inductance and the quadrature axis inductance under different direct-quadrature axis currents is determined.

9. A vehicle comprising a memory and a processor, the memory having stored therein a computer program executable on the processor, characterized in that, The processor executes the computer program to implement the method for determining the torque of the motor according to any one of claims 1 to 8.

10. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 9. The computer program is executed by the processor to implement the method for determining the torque of the motor according to any one of claims 1 to 8.

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