Motor active flux weakening method and device
By obtaining the cross-axis current deviation value to determine the adaptive parameters and adjusting the motor output torque, the stability and responsiveness issues of torque output of high-speed motors at high speeds are solved, and the motor achieves stability and rapid response at high speeds.
Patent Information
- Application Number
- CN202510899341.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-01
- Publication Date
- 2025-11-11
AI Technical Summary
High-speed motors struggle to respond quickly and stably to large torque outputs at high speeds, especially when torque requirements vary, making it difficult to balance torque output stability and instantaneous response.
By obtaining the deviation between the target quadrature-axis current and the actual quadrature-axis current, the adaptive parameters of the active field weakening module are determined, and the motor output torque is adjusted to ensure the stability of torque output and the instantaneous response at high speeds.
It expands the motor's operating speed range, ensuring the stability of torque output and instantaneous response at high speeds, while incurring no hardware costs, ensuring safety, reliability, and ease of maintenance.
Smart Images
Figure CN120934384A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of motor technology, and in particular to a method and apparatus for active field weakening of a motor. Background Technology
[0002] New energy vehicles are becoming increasingly popular, and their market share will further increase in the near future. Market anxiety about vehicle range is also becoming more prominent. Increasing the capacity of power batteries will undoubtedly lead to higher costs. However, improving the lightweighting and power density of electric drives can not only reduce the cost of electric drives but also reduce the energy consumption of the entire vehicle. One of the directions for lightweighting electric drives is high-speed motors. As the requirements for lightweighting electric drives become more and more stringent, high-speed permanent magnet synchronous motors are increasingly being used in vehicles.
[0003] When high-speed motors output large torque and high power at high speeds, they need to enter a deep field weakening operating range. Torque control of high-speed motors, especially active field weakening, is very difficult. Faced with the variable torque requirements at high speeds, it is difficult for high-speed motors to balance the stability of torque output and the instantaneousness of response. Summary of the Invention
[0004] This application provides an active field weakening method and apparatus for motors, which solves the problem that high-speed motors in the prior art cannot respond quickly and stably to the demand for high torque output, and enables high-speed motors to respond quickly and stably to the demand for high torque output.
[0005] In a first aspect, this application provides an active field weakening method for an electric motor, comprising:
[0006] If a target instruction is received, the target direct-axis current and target quadrature-axis current of the motor are determined based on the target torque; the target instruction is an instruction to output the target torque.
[0007] The target voltage magnitude is determined based on the target direct-axis current and the target quadrature-axis current.
[0008] Obtain the target quadrature-axis current error; the target quadrature-axis current error is the deviation between the target quadrature-axis current and the actual quadrature-axis current, and the target quadrature-axis current error is used to determine the adaptive parameters of the active field weakening module;
[0009] The target voltage magnitude and the target quadrature-axis current error are input into the active field weakening module, and the output torque of the motor is adjusted based on the active field weakening module; the deviation between the output torque and the target torque is within a preset range.
[0010] Optionally, if the absolute value of the target quadrature-axis current error is less than or equal to a first threshold, the adaptive parameter is a first target value;
[0011] If the absolute value of the target quadrature-axis current error is greater than or equal to the second threshold, the adaptive parameter is the second target value; the second target value is greater than the first target value.
[0012] If the absolute value of the target quadrature-axis current error is greater than the first threshold and less than the second threshold, the adaptive parameter is greater than the first target value, less than the second target value, and proportional to the absolute value of the target quadrature-axis current error.
[0013] Optionally, the active field weakening method for motors also includes:
[0014] Determine the target speed and the initial torque;
[0015] Based on the first torque, a step torque command is determined; the step torque command is a command that causes the torque to jump from zero to the first torque.
[0016] The first threshold is determined based on the target speed, the step torque command, the third target value, and the actual overshoot; the third target value is the initial value of the adaptive parameter, and the actual overshoot is the overshoot of the actual direct-axis current.
[0017] The second target value is determined based on the target speed, the step torque command, the third target value, and the response time; the response time is the time required for the motor to respond to the step torque command.
[0018] The second threshold is determined based on the target speed, the step torque command, the third target value, and the second target value;
[0019] The first target value is determined based on the target speed, the step torque command, the third target value, and the actual overshoot.
[0020] Optionally, the target speed is the motor speed when the actual direct-axis current of the motor is zero, the actual quadrature-axis current is zero, and the actual voltage magnitude is equal to the field weakening voltage;
[0021] The first torque is the maximum torque of the motor at the target speed when the active field weakening module is turned off.
[0022] Optionally, determining the first threshold based on the target speed, the step torque command, the third target value, and the actual overshoot includes:
[0023] When the motor speed is the target speed and the adaptive parameter is the third target value, the actual overshoot of the motor when responding to the step torque command under different parameters of the active field weakening module is detected.
[0024] The absolute value of the quadrature-axis current error when the actual overshoot equals the first target overshoot is taken as the first threshold.
[0025] The parameters of the active magnetic weakening module when the actual overshoot equals the first target overshoot are taken as the target parameters.
[0026] Optionally, determining the second target value based on the target speed, the step torque command, the third target value, and the response time includes:
[0027] The response time of the motor in response to the step torque command is detected when the motor is at the target speed, the parameters of the active field weakening module are the target parameters, and the adaptive coefficient increases sequentially from the third target value.
[0028] The adaptive parameter when the response duration is first less than or equal to the target duration is taken as the second target value.
[0029] Optionally, determining the second threshold based on the target rotational speed, the step torque command, the third target value, and the second target value includes:
[0030] The absolute value of the quadrature-axis current error at different moments in the target process of the motor responding to the step torque command is obtained when the motor is at the target speed, the parameters of the active field weakening module are the target parameters, and the adaptive coefficient increases sequentially from the third target value to the second target value.
[0031] The maximum absolute value of the cross-axis current error in the target process is taken as the second threshold.
[0032] Optionally, determining the first target value based on the target speed, the step torque command, the third target value, and the actual overshoot includes:
[0033] The actual overshoot of the motor when responding to the step torque command is obtained when the motor is at the target speed, the parameters of the active field weakening module are the target parameters, and the adaptive coefficient decreases sequentially from the third target value.
[0034] The adaptive coefficient at which the actual overshoot is first less than the second target overshoot is taken as the first target value.
[0035] Optionally, determining the target direct-axis current and target quadrature-axis current of the motor based on the target torque includes:
[0036] Determine the maximum torque-to-current ratio curve and the torque-to-current matrix; the maximum torque-to-current ratio curve is used to represent the relationship between torque and direct-axis current; the torque-to-current matrix is used to represent the relationship between torque, direct-axis current, and quadrature-axis current.
[0037] Based on the target torque versus the maximum torque-current ratio curve, determine the first direct-axis current;
[0038] Based on the active field weakening module, the second direct-axis current is determined;
[0039] The target direct-axis current is determined based on the first direct-axis current and the second direct-axis current;
[0040] The target quadrature axis current is determined based on the target direct axis current and the torque current matrix.
[0041] Secondly, this application also provides an active field weakening device for a motor, comprising:
[0042] The first determining module is used to determine the target direct-axis current and the target quadrature-axis current of the motor based on the target torque if a target instruction is received; the target instruction is an instruction to output the target torque.
[0043] The second determining module is used to determine the target voltage magnitude based on the target direct-axis current and the target quadrature-axis current;
[0044] The acquisition module is used to obtain the target quadrature-axis current error; the target quadrature-axis current error is the deviation between the target quadrature-axis current and the actual quadrature-axis current, and the target quadrature-axis current error is used to determine the adaptive parameters of the active field weakening module;
[0045] An adjustment module is used to input the target voltage magnitude and the target quadrature-axis current error into the active field weakening module, and adjust the output torque of the motor based on the active field weakening module; the deviation between the output torque and the target torque is within a preset range.
[0046] Thirdly, this application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method described in the first aspect.
[0047] Fourthly, this application also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in the first aspect.
[0048] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the method described in the first aspect.
[0049] The active field weakening method and apparatus for motors provided in this application determine the adaptive parameters of the active field weakening module by obtaining the deviation between the target quadrature-axis current and the actual quadrature-axis current. This expands the operating speed range of the motor and ensures the stability of torque output and the instantaneous response of the motor at high speeds. Moreover, this method has no hardware cost, is safe and reliable, and is highly maintainable. Attached Figure Description
[0050] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0051] Figure 1 This is one of the flowcharts of the active field weakening method for motors provided in the embodiments of this application;
[0052] Figure 2 This is the second flowchart illustrating the active field weakening method for motors provided in this application embodiment;
[0053] Figure 3 This is a schematic diagram showing the relationship between the absolute value of the target quadrature-axis current error and the adaptive parameters provided in the embodiments of this application;
[0054] Figure 4 This is a schematic diagram of the maximum torque-to-current ratio curve provided in the embodiments of this application;
[0055] Figure 5 This is a schematic diagram of the process for determining the target direct-axis current and target quadrature-axis current of a motor based on the target torque, provided in an embodiment of this application.
[0056] Figure 6 This is a schematic diagram of the structure of the motor active field weakening device provided in the embodiments of this application;
[0057] Figure 7 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation
[0058] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0059] This application provides an active field weakening method for a motor, the execution subject of which can be an electronic device, such as a controller. The following description uses a controller as the execution subject of the method. Figure 1 This is one of the flowcharts illustrating the active field weakening method for a motor provided in this application. (Refer to...) Figure 1 The method may include:
[0060] Step 110: If a target instruction is received, determine the target direct-axis current and target quadrature-axis current of the motor based on the target torque; the target instruction is the instruction to output the target torque.
[0061] Step 120: Determine the target voltage magnitude based on the target direct-axis current and the target quadrature-axis current;
[0062] Step 130: Obtain the target quadrature-axis current error; the target quadrature-axis current error is the deviation between the target quadrature-axis current and the actual quadrature-axis current. The target quadrature-axis current error is used to determine the adaptive parameters of the active field weakening module.
[0063] Step 140: Input the target voltage magnitude and target quadrature axis current error into the active field weakening module, and adjust the motor output torque based on the active field weakening module; the deviation between the output torque and the target torque is within the preset range.
[0064] In step 110, if the motor receives a command to output the target torque, the controller can determine the target direct-axis current and the target quadrature-axis current of the motor based on the target torque.
[0065] In step 120, the controller can perform PI control based on the target direct-axis current id* and the target quadrature-axis current iq*, and output the quadrature-axis and direct-axis voltages. The target voltage magnitude Us is calculated by taking the square root of the quadrature-axis and direct-axis voltages.
[0066] Figure 2 This is a second schematic flowchart of the active field weakening method for motors provided in the embodiments of this application, as shown below. Figure 2 As shown, in step 130, the controller can obtain the target quadrature-axis current error iq. err The adaptive parameter k of the active field weakening module is controlled by the target quadrature-axis current error. This adaptive parameter k optimizes the proportional and integral parameters of the active field weakening PI control in real time, achieving adaptive PI control. The target quadrature-axis current error is the deviation between the target quadrature-axis current and the actual quadrature-axis current, and this error is proportional to the adaptive parameter of the active field weakening module within a certain range.
[0067] In step 140, the controller can input the target voltage magnitude and the target quadrature axis current error into the active field weakening module. The active field weakening module determines whether to adjust the output torque of the motor based on the magnitude of the target voltage magnitude, and adjusts the output torque of the motor according to the adaptive parameters determined by the target quadrature axis current error when adjustment is required.
[0068] The active field weakening method for motors provided in this application determines the adaptive parameters of the active field weakening module by obtaining the deviation between the target quadrature-axis current and the actual quadrature-axis current. This expands the operating speed range of the motor and ensures the stability of torque output and the instantaneous response of the motor at high speeds. Moreover, this method has no hardware cost, is safe and reliable, and is highly maintainable.
[0069] In some embodiments, if the absolute value of the target quadrature current error is less than or equal to a first threshold, the adaptive parameter is a first target value; if the absolute value of the target quadrature current error is greater than or equal to a second threshold, the adaptive parameter is a second target value; the second target value is greater than the first target value; if the absolute value of the target quadrature current error is greater than the first threshold and less than the second threshold, the adaptive parameter is greater than the first target value, less than the second target value, and proportional to the absolute value of the target quadrature current error.
[0070] Figure 3 This is a schematic diagram showing the relationship between the absolute value of the target quadrature-axis current error and the adaptive parameters provided in the embodiments of this application. Figure 3 in,iq errmin Let iq be the first threshold. errmax For the second threshold, k min k is the first target value. max This is the second target value. When the absolute value of the target quadrature-axis current error is lower than the lower limit iq... errmin When the adaptive coefficient k reaches its minimum value k min When the absolute value of the target quadrature-axis current error is higher than the upper limit iq errmax When the adaptive coefficient k reaches its maximum value k max When the absolute value of the target quadrature-axis current error is at iq errmin ~iq errmax When the interval is between, linear interpolation yields the adaptive coefficient k.
[0071] The active field weakening method for motors provided in this application determines the adaptive parameters of the active field weakening module by obtaining the deviation between the target quadrature-axis current and the actual quadrature-axis current. This expands the operating speed range of the motor and ensures the stability of torque output and the instantaneous response of the motor at high speeds. Moreover, this method has no hardware cost, is safe and reliable, and is highly maintainable.
[0072] In some embodiments, the active field weakening method for a motor further includes: determining a target speed and a first torque; determining a step torque command based on the first torque; the step torque command is a command for the torque to step from zero to the first torque; determining a first threshold based on the target speed, the step torque command, a third target value, and an actual overshoot; the third target value is the initial value of an adaptive parameter, and the actual overshoot is the overshoot of the actual direct-axis current; determining a second target value based on the target speed, the step torque command, the third target value, and a response time; the response time is the time required for the motor to respond to the step torque command; determining the second threshold based on the target speed, the step torque command, the third target value, and the second target value; and determining the first target value based on the target speed, the step torque command, the third target value, and the actual overshoot.
[0073] Furthermore, in some embodiments, the target speed is the motor speed when the actual direct-axis current of the motor is zero, the actual quadrature-axis current is zero, and the actual voltage magnitude is equal to the field weakening voltage; the first torque is the maximum torque of the motor at the target speed when the active field weakening module is turned off.
[0074] Before confirming the field weakening parameters, a field weakening test condition needs to be selected, typically at rated voltage. Specifically, the controller can set the actual direct-axis and quadrature-axis currents id and iq to 0, and use a dynamometer to slowly increase the motor speed. The actual voltage magnitude will increase as the motor speed increases. When a certain speed is reached, the actual voltage magnitude is exactly equal to the field weakening voltage Usref. This speed is selected as the target speed, Speed. test .
[0075] The controller shuts down the active field weakening module, causing the output current id of the active field weakening module to... weak The value is 0. By inputting the direct and quadrature shaft current command values, the Speed at rated voltage and target speed is calibrated. test The maximum torque under these conditions is the first torque Te. max During this process, the actual voltage magnitude boundary is Usref, and the phase current must not exceed the operating range of the controller's power device. Ideally, it should be within 90% of the power device's operating limit to avoid current overshoot and damage to the power device during debugging.
[0076] The active field weakening method for motors provided in this application determines the adaptive parameters of the active field weakening module by obtaining the deviation between the target quadrature-axis current and the actual quadrature-axis current. This expands the operating speed range of the motor and ensures the stability of torque output and the instantaneous response of the motor at high speeds. Moreover, this method has no hardware cost, is safe and reliable, and is highly maintainable.
[0077] In some embodiments, determining a first threshold based on the target speed, step torque command, third target value, and actual overshoot includes: when the motor speed is the target speed and the adaptive parameter is the third target value, detecting the actual overshoot of the motor when responding to the step torque command under different parameters of the active field weakening module; using the quadrature-axis current error when the actual overshoot equals the first target overshoot as the first threshold; and using the parameters of the active field weakening module when the actual overshoot equals the first target overshoot as the target parameters.
[0078] To confirm the weak magnetic parameters, start with the first threshold iq. errmin Initially, the controller activates the field weakening module, and the adaptive parameter is initialized to the third target value, which can be 1. The adaptive parameter k is fixed at 1. The PI parameter of the active field weakening module is adjusted. The test operating voltage is the rated voltage, and the speed is the target speed. test Give a step torque command (the commanded torque jumps from 0 to the maximum torque Te). max The system monitors the actual overshoot of the direct-axis current id (the difference between the minimum value of id and the steady-state value during the field weakening process). When the actual overshoot is equal to the first target overshoot (e.g., 5%), the field weakening PI parameters are fixed. The PI parameters of the active field weakening module at this time are used as the target parameters, and the absolute value of the quadrature-axis current error fluctuation amplitude in the steady state at this time is recorded as the first threshold iq. errmin .
[0079] Furthermore, in some embodiments, the second target value is determined based on the target speed, the step torque command, the third target value, and the response time, including: detecting the response time of the motor in response to the step torque command when the motor is at the target speed, the parameters of the active field weakening module are the target parameters, and the adaptive coefficient increases sequentially from the third target value; and taking the adaptive parameter when the response time is less than or equal to the target time for the first time as the second target value.
[0080] Furthermore, in some embodiments, determining a second threshold based on the target speed, step torque command, third target value, and second target value includes: obtaining the absolute value of the quadrature-axis current error at different moments in the target process when the motor is at the target speed, the parameters of the active field weakening module are the target parameters, and the adaptive coefficient increases sequentially from the third target value to the second target value; and taking the maximum value of the absolute value of the quadrature-axis current error in the target process as the second threshold.
[0081] When the motor is at the target speed Speed test The parameters of the active field weakening module are the target parameters. The controller controls the adaptive parameter k to increase sequentially from the third target value to perform a step torque field weakening test. When the response time of the motor to the step torque command is less than or equal to the target time for the first time, the adaptive parameter at this time is taken as the second target value k.max The cross-axis current error during the test (i.e., the target process) is recorded, and the maximum absolute value of the cross-axis current error is used as the second threshold iq. errmax .
[0082] Furthermore, in some embodiments, determining the first target value based on the target speed, the step torque command, the third target value, and the actual overshoot includes: obtaining the actual overshoot when the motor responds to the step torque command, when the motor is at the target speed, the parameters of the active field weakening module are the target parameters, and the adaptive coefficient decreases sequentially from the third target value; and taking the adaptive coefficient when the actual overshoot is less than the second target overshoot for the first time as the first target value.
[0083] The target parameters and iq of the active field weakening module were determined. errmin iq errmax k max Afterwards, the controller performs another step torque field weakening test, fine-tuning the initial value of the adaptive coefficient (i.e., the third target value) to obtain the first target value. When the motor reaches the target speed (Speed),... test The parameters of the active field weakening module are the target parameters. When the adaptive coefficient decreases sequentially from the third target value, the controller obtains the actual overshoot when the motor responds to the step torque command, and takes the adaptive coefficient when the actual overshoot is less than the second target overshoot (e.g., 5%) for the first time as the first target value k. min .
[0084] The active field weakening method for motors provided in this application determines the adaptive parameters of the active field weakening module by obtaining the deviation between the target quadrature-axis current and the actual quadrature-axis current. This expands the operating speed range of the motor and ensures the stability of torque output and the instantaneous response of the motor at high speeds. Moreover, this method has no hardware cost, is safe and reliable, and is highly maintainable.
[0085] In some embodiments, determining the target direct-axis current and target quadrature-axis current of the motor based on the target torque includes: determining a maximum torque-to-current ratio curve and a torque-to-current matrix; the maximum torque-to-current ratio curve is used to represent the relationship between torque and direct-axis current; the torque-to-current matrix is used to represent the relationship between torque, direct-axis current, and quadrature-axis current; determining a first direct-axis current based on the target torque and the maximum torque-to-current ratio curve; determining a second direct-axis current based on the active field weakening module; determining a target direct-axis current based on the first direct-axis current and the second direct-axis current; and determining a target quadrature-axis current based on the target direct-axis current and the torque-to-current matrix.
[0086] The controller can obtain the maximum torque per ampere (MTPA) curve of the motor. Figure 4This is a schematic diagram of the maximum torque-to-current ratio curve provided in the embodiments of this application. The maximum torque-to-current ratio curve can reflect the relationship between torque and direct-axis current. The maximum torque-to-current ratio curve can be obtained through bench calibration, or it can be obtained from the motor parameters provided by the motor manufacturer, according to the torque formula Te=P×(ψ×iq+(L d -L q The value is obtained by calculating ()×id×iq), where Te is the electromagnetic torque, P is the number of pole pairs of the motor, ψ is the flux linkage of the permanent magnet, and L is the magnetic flux density. d L q These are the direct-axis and quadrature-axis inductances of the motor, respectively, and id and iq are the direct-axis and quadrature-axis currents of the motor, respectively.
[0087] The controller can obtain the torque-current matrix. The torque-current matrix is shown in Table 1 below:
[0088]
[0089] Table 1 Torque Current Matrix
[0090] The torque-current matrix can be obtained through bench calibration or by calculating it based on the torque formula using motor parameters provided by the motor manufacturer. The final result is a two-dimensional table that allows querying the quadrature-axis current using both direct-axis current and torque.
[0091] Figure 5 This is a schematic diagram illustrating the process of determining the target direct-axis current and target quadrature-axis current of a motor based on the target torque, as provided in an embodiment of this application. Figure 5 As shown, during torque control, the motor receives the target torque Te from the vehicle and then calculates the target direct-axis and quadrature-axis currents id* and iq* in real time. The target direct-axis current consists of two parts: one part is the first direct-axis current idmtpa obtained by interpolation based on the MTPA curve, and the other part is the second direct-axis current idweak output by the active field weakening module through the real-time voltage modulus. The sum of idmtpa and idweak is calculated. If the sum is greater than idmin, the sum is used as the target direct-axis current id*. If the sum is less than or equal to idmin, idmin is used as the target direct-axis current id*. The target quadrature-axis current iq* is obtained based on the target direct-axis current id* according to the torque current matrix.
[0092] The active field weakening method for motors provided in this application determines the target direct-axis current and target quadrature-axis current by using the target torque, the maximum torque-to-current ratio curve, the torque-to-current matrix, and the active field weakening module. This is used to calculate the input (target voltage magnitude) of the subsequent active field weakening module, thereby expanding the operating speed range of the motor and ensuring the stability of the torque output and the instantaneous response of the motor at high speeds.
[0093] The active field weakening device for motors provided in this application is described below. The active field weakening device for motors described below can be referred to in correspondence with the active field weakening method for motors described above.
[0094] Figure 6 This is a schematic diagram of the structure of the active field weakening device for motors provided in an embodiment of this application. (Refer to...) Figure 6 The active field weakening device for motors provided in this application embodiment may include:
[0095] The first determining module 610 is used to determine the target direct-axis current and the target quadrature-axis current of the motor based on the target torque if a target instruction is received; the target instruction is an instruction to output the target torque.
[0096] The second determining module 620 is used to determine the target voltage magnitude based on the target direct-axis current and the target quadrature-axis current;
[0097] The acquisition module 630 is used to acquire the target quadrature-axis current error; the target quadrature-axis current error is the deviation between the target quadrature-axis current and the actual quadrature-axis current, and the target quadrature-axis current error is used to determine the adaptive parameters of the active field weakening module;
[0098] The adjustment module 640 is used to input the target voltage magnitude and the target quadrature axis current error into the active field weakening module, and adjust the output torque of the motor based on the active field weakening module; the deviation between the output torque and the target torque is within a preset range.
[0099] The active field weakening device for motors provided in this application determines the adaptive parameters of the active field weakening module by obtaining the deviation between the target quadrature-axis current and the actual quadrature-axis current. This expands the operating speed range of the motor and ensures the stability of torque output and the instantaneous response of the motor at high speeds. Moreover, this method has no hardware cost, is safe and reliable, and is highly maintainable.
[0100] In some embodiments, if the absolute value of the target quadrature-axis current error is less than or equal to a first threshold, the adaptive parameter is a first target value;
[0101] If the absolute value of the target quadrature-axis current error is greater than or equal to the second threshold, the adaptive parameter is the second target value; the second target value is greater than the first target value.
[0102] If the absolute value of the target quadrature-axis current error is greater than the first threshold and less than the second threshold, the adaptive parameter is greater than the first target value, less than the second target value, and proportional to the absolute value of the target quadrature-axis current error.
[0103] In some embodiments, the adjustment module is further configured to:
[0104] Determine the target speed and the initial torque;
[0105] Based on the first torque, a step torque command is determined; the step torque command is a command that causes the torque to jump from zero to the first torque.
[0106] The first threshold is determined based on the target speed, the step torque command, the third target value, and the actual overshoot; the third target value is the initial value of the adaptive parameter, and the actual overshoot is the overshoot of the actual direct-axis current.
[0107] The second target value is determined based on the target speed, the step torque command, the third target value, and the response time; the response time is the time required for the motor to respond to the step torque command.
[0108] The second threshold is determined based on the target speed, the step torque command, the third target value, and the second target value;
[0109] The first target value is determined based on the target speed, the step torque command, the third target value, and the actual overshoot.
[0110] In some embodiments, the target speed is the motor speed when the actual direct-axis current of the motor is zero, the actual quadrature-axis current is zero, and the actual voltage magnitude is equal to the field weakening voltage;
[0111] The first torque is the maximum torque of the motor at the target speed when the active field weakening module is turned off.
[0112] In some embodiments, the adjustment module is used for:
[0113] When the motor speed is the target speed and the adaptive parameter is the third target value, the actual overshoot of the motor when responding to the step torque command under different parameters of the active field weakening module is detected.
[0114] The absolute value of the quadrature-axis current error when the actual overshoot equals the first target overshoot is taken as the first threshold.
[0115] The parameters of the active magnetic weakening module when the actual overshoot equals the first target overshoot are taken as the target parameters.
[0116] In some embodiments, the adjustment module is used for:
[0117] The response time of the motor in response to the step torque command is detected when the motor is at the target speed, the parameters of the active field weakening module are the target parameters, and the adaptive coefficient increases sequentially from the third target value.
[0118] The adaptive parameter when the response duration is first less than or equal to the target duration is taken as the second target value.
[0119] In some embodiments, the adjustment module is used for:
[0120] The absolute value of the quadrature-axis current error at different moments in the target process of the motor responding to the step torque command is obtained when the motor is at the target speed, the parameters of the active field weakening module are the target parameters, and the adaptive coefficient increases sequentially from the third target value to the second target value.
[0121] The maximum absolute value of the cross-axis current error in the target process is taken as the second threshold.
[0122] In some embodiments, the adjustment module is used for:
[0123] The actual overshoot of the motor when responding to the step torque command is obtained when the motor is at the target speed, the parameters of the active field weakening module are the target parameters, and the adaptive coefficient decreases sequentially from the third target value.
[0124] The adaptive coefficient at which the actual overshoot is first less than the second target overshoot is taken as the first target value.
[0125] In some embodiments, the first determining module is configured to:
[0126] Determine the maximum torque-to-current ratio curve and the torque-to-current matrix; the maximum torque-to-current ratio curve is used to represent the relationship between torque and direct-axis current; the torque-to-current matrix is used to represent the relationship between torque, direct-axis current, and quadrature-axis current.
[0127] Based on the target torque versus the maximum torque-current ratio curve, determine the first direct-axis current;
[0128] Based on the active field weakening module, the second direct-axis current is determined;
[0129] The target direct-axis current is determined based on the first direct-axis current and the second direct-axis current;
[0130] The target quadrature axis current is determined based on the target direct axis current and the torque current matrix.
[0131] Specifically, the above-mentioned active field weakening device for motors provided in this application embodiment can realize all the method steps implemented by the method embodiment with the controller as the execution subject, and can achieve the same technical effect. Here, the parts that are the same as those in the method embodiment and the beneficial effects will not be described in detail.
[0132] Figure 7 This is a schematic diagram of the structure of the electronic device provided in an embodiment of this application. For example... Figure 7 As shown, the electronic device may include: a processor 710, a communication interface 720, a memory 730, and a communication bus 740, wherein the processor 710, the communication interface 720, and the memory 730 communicate with each other via the communication bus 740. The processor 710 can call logic instructions in the memory 730 to execute an active field weakening method for the motor, such as:
[0133] If a target instruction is received, the target direct-axis current and target quadrature-axis current of the motor are determined based on the target torque; the target instruction is an instruction to output the target torque.
[0134] The target voltage magnitude is determined based on the target direct-axis current and the target quadrature-axis current.
[0135] Obtain the target quadrature-axis current error; the target quadrature-axis current error is the deviation between the target quadrature-axis current and the actual quadrature-axis current, and the target quadrature-axis current error is used to determine the adaptive parameters of the active field weakening module;
[0136] The target voltage magnitude and the target quadrature-axis current error are input into the active field weakening module, and the output torque of the motor is adjusted based on the active field weakening module; the deviation between the output torque and the target torque is within a preset range.
[0137] Furthermore, the logical instructions in the aforementioned memory 730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.
[0138] On the other hand, this application also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the motor active field weakening method provided by the above methods, including, for example:
[0139] If a target instruction is received, the target direct-axis current and target quadrature-axis current of the motor are determined based on the target torque; the target instruction is an instruction to output the target torque.
[0140] The target voltage magnitude is determined based on the target direct-axis current and the target quadrature-axis current.
[0141] Obtain the target quadrature-axis current error; the target quadrature-axis current error is the deviation between the target quadrature-axis current and the actual quadrature-axis current, and the target quadrature-axis current error is used to determine the adaptive parameters of the active field weakening module;
[0142] The target voltage magnitude and the target quadrature-axis current error are input into the active field weakening module, and the output torque of the motor is adjusted based on the active field weakening module; the deviation between the output torque and the target torque is within a preset range.
[0143] Furthermore, this application also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to perform the steps of the motor active field weakening method provided by the above methods, such as including:
[0144] If a target instruction is received, the target direct-axis current and target quadrature-axis current of the motor are determined based on the target torque; the target instruction is an instruction to output the target torque.
[0145] The target voltage magnitude is determined based on the target direct-axis current and the target quadrature-axis current.
[0146] Obtain the target quadrature-axis current error; the target quadrature-axis current error is the deviation between the target quadrature-axis current and the actual quadrature-axis current, and the target quadrature-axis current error is used to determine the adaptive parameters of the active field weakening module;
[0147] The target voltage magnitude and the target quadrature-axis current error are input into the active field weakening module, and the output torque of the motor is adjusted based on the active field weakening module; the deviation between the output torque and the target torque is within a preset range.
[0148] The device embodiments described above are merely illustrative. 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 modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.
[0149] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.
[0150] It should also be noted that in the embodiments of this application, the terms "first," "second," etc., are used to distinguish similar objects, and not to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first" and "second" are generally of the same class, and the number of objects is not limited. For example, the first object can be one or more.
[0151] In this application embodiment, the term "and / or" describes the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.
[0152] In this application's embodiments, "determine B based on A" means that factor A must be considered when determining B. It is not limited to "B can be determined based solely on A," but should also include: "determine B based on A and C," "determine B based on A, C, and E," "determine C based on A, and further determine B based on C," etc. Additionally, it can include using A as a condition for determining B, for example, "when A meets the first condition, determine B using the first method"; another example, "when A meets the second condition, determine B," etc.; another example, "when A meets the third condition, determine B based on the first parameter," etc. Of course, it can also be a condition where A is a factor in determining B, for example, "when A meets the first condition, determine C using the first method, and further determine B based on C," etc.
[0153] In the embodiments of this application, the term "multiple" refers to two or more, and other quantifiers are similar.
[0154] In the embodiments of this application, the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.
[0155] In this application embodiment, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application embodiment based on the specific circumstances.
[0156] In this embodiment of the application, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0157] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0158] Finally, it should be noted that the above 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.
Claims
1. A method for active field weakening of a motor, characterized in that, include: If a target instruction is received, the target direct-axis current and the target quadrature-axis current of the motor are determined based on the target torque; The target command is the command to output the target torque; The target voltage magnitude is determined based on the target direct-axis current and the target quadrature-axis current. Obtain the target quadrature-axis current error; The target quadrature-axis current error is the deviation between the target quadrature-axis current and the actual quadrature-axis current. The target quadrature-axis current error is used to determine the adaptive parameters of the active field weakening module. The target voltage magnitude and the target quadrature-axis current error are input into the active field weakening module, and the output torque of the motor is adjusted based on the active field weakening module; The deviation between the output torque and the target torque is within a preset range.
2. The active field weakening method for a motor according to claim 1, characterized in that, If the absolute value of the target quadrature-axis current error is less than or equal to the first threshold, the adaptive parameter is the first target value; If the absolute value of the target quadrature-axis current error is greater than or equal to the second threshold, the adaptive parameter is the second target value; the second target value is greater than the first target value. If the absolute value of the target quadrature-axis current error is greater than the first threshold and less than the second threshold, the adaptive parameter is greater than the first target value, less than the second target value, and proportional to the absolute value of the target quadrature-axis current error.
3. The active field weakening method for a motor according to claim 2, characterized in that, Also includes: Determine the target speed and the initial torque; Based on the first torque, determine the step torque command; The step torque command is an instruction for the torque to jump from zero to the first torque; The first threshold is determined based on the target speed, the step torque command, the third target value, and the actual overshoot. The third target value is the initial value of the adaptive parameter, and the actual overshoot is the overshoot of the actual direct-axis current. The second target value is determined based on the target speed, the step torque command, the third target value, and the response time. The response time is the time required for the motor to respond to the step torque command; The second threshold is determined based on the target speed, the step torque command, the third target value, and the second target value; The first target value is determined based on the target speed, the step torque command, the third target value, and the actual overshoot.
4. The active field weakening method for a motor according to claim 3, characterized in that, The target speed is the motor speed when the actual direct-axis current of the motor is zero, the actual quadrature-axis current is zero, and the actual voltage magnitude is equal to the field weakening voltage. The first torque is the maximum torque of the motor at the target speed when the active field weakening module is turned off.
5. The active field weakening method for a motor according to claim 3, characterized in that, The determination of the first threshold based on the target speed, the step torque command, the third target value, and the actual overshoot includes: When the motor speed is the target speed and the adaptive parameter is the third target value, the actual overshoot of the motor when responding to the step torque command under different parameters of the active field weakening module is detected. The absolute value of the quadrature-axis current error when the actual overshoot equals the first target overshoot is taken as the first threshold. The parameters of the active magnetic weakening module when the actual overshoot equals the first target overshoot are taken as the target parameters.
6. The active field weakening method for a motor according to claim 5, characterized in that, The step of determining the second target value based on the target speed, the step torque command, the third target value, and the response time includes: The response time of the motor in response to the step torque command is detected when the motor is at the target speed, the parameters of the active field weakening module are the target parameters, and the adaptive coefficient increases sequentially from the third target value. The adaptive parameter when the response duration is first less than or equal to the target duration is taken as the second target value.
7. The active field weakening method for a motor according to claim 5, characterized in that, Determining the second threshold based on the target speed, the step torque command, the third target value, and the second target value includes: The absolute value of the quadrature-axis current error at different moments in the target process of the motor responding to the step torque command is obtained when the motor is at the target speed, the parameters of the active field weakening module are the target parameters, and the adaptive coefficient increases sequentially from the third target value to the second target value. The maximum absolute value of the cross-axis current error in the target process is taken as the second threshold.
8. The active field weakening method for a motor according to claim 5, characterized in that, Determining the first target value based on the target speed, the step torque command, the third target value, and the actual overshoot includes: The actual overshoot of the motor when responding to the step torque command is obtained when the motor is at the target speed, the parameters of the active field weakening module are the target parameters, and the adaptive coefficient decreases sequentially from the third target value. The adaptive coefficient at which the actual overshoot is first less than the second target overshoot is taken as the first target value.
9. The active field weakening method for a motor according to claim 1, characterized in that, The determination of the target direct-axis current and target quadrature-axis current of the motor based on the target torque includes: Determine the maximum torque-to-current ratio curve and the torque-to-current matrix; the maximum torque-to-current ratio curve is used to represent the relationship between torque and direct-axis current; the torque-to-current matrix is used to represent the relationship between torque, direct-axis current, and quadrature-axis current. Based on the target torque versus the maximum torque-current ratio curve, determine the first direct-axis current; Based on the active field weakening module, the second direct-axis current is determined; The target direct-axis current is determined based on the first direct-axis current and the second direct-axis current; The target quadrature axis current is determined based on the target direct axis current and the torque current matrix.
10. An active field weakening device for an electric motor, characterized in that, include: The first determining module is used to determine the target direct-axis current and the target quadrature-axis current of the motor based on the target torque if a target instruction is received. The target command is the command to output the target torque; The second determining module is used to determine the target voltage magnitude based on the target direct-axis current and the target quadrature-axis current; The acquisition module is used to obtain the target quadrature-axis current error; The target quadrature-axis current error is the deviation between the target quadrature-axis current and the actual quadrature-axis current. The target quadrature-axis current error is used to determine the adaptive parameters of the active field weakening module. The adjustment module is used to input the target voltage magnitude and the target quadrature axis current error into the active field weakening module, and adjust the output torque of the motor based on the active field weakening module; The deviation between the output torque and the target torque is within a preset range.