Motor torque ripple suppression method, controller and vehicle

Abstract

The invention discloses a motor torque ripple suppression method, a controller and a vehicle, and relates to the technical field of vehicles. The motor torque ripple suppression method comprises the steps of collecting a time domain torque error of a motor in a time domain, and mapping the time domain torque error to a space domain associated with a rotor position of the motor to obtain a torque error-rotor position comparison table; iteratively updating the spatial domain torque compensation scale based on the torque error-rotor position comparison table; inquiring the updated spatial domain torque compensation scale according to the real-time rotor position to obtain a torque compensation signal; and performing torque compensation control on the motor according to the torque compensation signal. According to the method, the torque ripple suppression of the motor can be realized, so that the electromagnetic noise can be reduced, the power output stability is improved, and the driving experience of a driver and passengers is improved.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a method for suppressing motor torque ripple, a controller, and a vehicle. Background Technology

[0002] Torque ripple in electric motors is a key factor contributing to electromagnetic noise and motor vibration. It not only affects the system's quietness but also the motor's reliability and lifespan. Torque ripple directly manifests as electromagnetic noise, which, compared to traditional internal combustion engine noise, has a higher frequency and is more easily perceived by the human ear, thus impacting driving comfort. Especially during low-speed cruising or when stationary, high-frequency electromagnetic noise can cause discomfort for the user. Severe torque ripple not only increases energy loss in the motor drive system but also leads to bearing fretting wear, stator winding insulation aging, and fatigue damage to structural components, thereby shortening the motor's lifespan and affecting the long-term reliability of the entire vehicle. Summary of the Invention

[0003] The purpose of this invention is to provide a method for suppressing motor torque ripple, a drive system, and a vehicle, so as to suppress motor torque ripple, reduce electromagnetic noise, improve power output smoothness, and enhance the driving experience for passengers.

[0004] In a first aspect, embodiments of the present invention propose a method for suppressing motor torque ripple. The method includes: acquiring the time-domain torque error of the motor in the time domain, and mapping the time-domain torque error to a spatial domain associated with the rotor position of the motor to obtain a torque error-rotor position lookup table; iteratively updating a spatial domain torque compensation table based on the torque error-rotor position lookup table; querying the updated spatial domain torque compensation table according to the real-time rotor position to obtain a torque compensation signal; and performing torque compensation control on the motor according to the torque compensation signal.

[0005] In some embodiments, mapping the time-domain torque error to a spatial domain associated with the rotor position of the motor includes: taking one electrical cycle of the motor rotor as the basic period, and resampling the time-domain torque error that varies with time as a function of an interpolation algorithm based on the rotor position into a spatial domain torque error that varies with spatial position.

[0006] In some embodiments, the spatial domain torque compensation scale is updated using the following formula:

[0007] in, This represents the torque compensation amount at the k-th index position in the updated spatial domain voltage compensation table. This represents the torque compensation amount at the k-th index position in the spatial domain voltage compensation table before the update. This represents the torque error at the k-th index position in the torque error-rotor position lookup table. N represents the length of the spatial domain voltage compensation scale, Q represents the forgetting factor, and G represents the learning gain.

[0008] In some embodiments, obtaining the torque compensation signal by querying the updated spatial domain torque compensation table based on the real-time rotor position includes: calculating the index position corresponding to the real-time rotor position using the following formula:

[0009] in, Indicates the index position, The real-time rotor position is represented by N, and the length of the spatial domain torque compensation table is represented by N. The updated spatial domain torque compensation table is queried according to the index position to obtain the torque compensation signal, or the torque compensation signal is calculated by linear interpolation based on the query result.

[0010] In some embodiments, before querying the updated spatial domain torque compensation table based on the index position, the method further includes: calculating the required phase lead compensation angle based on the estimated system control delay time; calculating the index lead amount based on the phase lead compensation angle and the length of the spatial domain torque compensation table; and correcting the index position using the index lead amount.

[0011] In some embodiments, the method further includes: increasing the phase lead compensation angle by a preset step size within multiple consecutive electrical cycles; running torque compensation control at each phase lead compensation angle and recording the sum of the absolute values ​​of torque errors within one electrical cycle; stopping the search when the summation result changes from decreasing to increasing, and determining the phase lead compensation angle corresponding to the minimum value as the optimal value for subsequent control.

[0012] In some embodiments, the step of performing torque compensation control on the motor based on the torque compensation signal includes: converting the torque compensation signal into a q-axis current compensation amount, and superimposing the q-axis current compensation amount onto a q-axis current reference value; and performing PI control based on the superimposed q-axis current reference value.

[0013] In some embodiments, the method further includes: when the time-domain torque error is detected to be greater than or equal to an error threshold, pausing the iterative update of the spatial domain torque compensation table; and resuming the iterative update of the spatial domain torque compensation table when the time-domain torque error is detected to be less than the error threshold.

[0014] In a second aspect, embodiments of the present invention provide a controller, including a memory, a processor, and a computer program stored in the memory. When the computer program is executed by the processor, it implements the motor torque ripple suppression method described in the first aspect embodiment.

[0015] Thirdly, embodiments of the present invention provide a vehicle including the controller described in the second aspect of the embodiments.

[0016] The motor torque ripple suppression method, controller, and vehicle of this invention first collect the time-domain torque error of the motor in the time domain and map the time-domain torque error to a spatial domain associated with the rotor position of the motor, obtaining a torque error-rotor position lookup table. Based on the torque error-rotor position lookup table, the spatial domain torque compensation table is iteratively updated. The updated spatial domain torque compensation table is then queried according to the real-time rotor position to obtain a torque compensation signal. Finally, torque compensation control is performed on the motor based on the torque compensation signal. This achieves motor torque ripple suppression, thereby reducing electromagnetic noise, improving power output smoothness, and enhancing the driving experience for passengers. Attached Figure Description

[0017] Figure 1 This is a flowchart of the motor torque ripple suppression method according to an embodiment of the present invention; Figure 2 This is a system structure diagram of a motor torque ripple suppression method according to a specific embodiment of the present invention; Figure 3 This is a flowchart of a motor torque ripple suppression method according to a specific embodiment of the present invention; Figure 4 This is a schematic diagram of the iterative update process according to an embodiment of the present invention; Figure 5 This is a structural block diagram of a controller according to an embodiment of the present invention. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0019] The following description, with reference to the accompanying drawings, outlines an embodiment of the motor torque ripple suppression method, controller, and vehicle of the present invention.

[0020] Figure 1 This is a flowchart of the motor torque ripple suppression method according to an embodiment of the present invention.

[0021] like Figure 1As shown, the motor torque ripple suppression method includes: S1. Collect the time-domain torque error of the motor in the time domain, and map the time-domain torque error to the spatial domain associated with the rotor position of the motor to obtain the torque error-rotor position lookup table.

[0022] For example, the motor can be a permanent magnet synchronous motor. For instance... Figure 2 , Figure 3 As shown, acquiring the time-domain torque error of the motor in the time domain includes: real-time acquisition of the time-domain torque signal during motor operation, subtracting the time-domain torque signal from the reference torque to obtain the time-domain torque error. The time-domain torque signal can be obtained through... Figure 2 The torque observer shown estimates the torque. Simultaneously with acquiring the time-domain torque signal, the rotor position at time t is also acquired. , and according to the formula calculate The corresponding index position in the spatial domain array (Also known as storage sites), N represents dividing one rotational electrical cycle of the rotor into N equal parts. Based on the rotor position... When calculating the corresponding storage location k, the integer rounding down is used, and the range of k is... .

[0023] In one embodiment, mapping the time-domain torque error to a spatial domain associated with the rotor position of the motor includes: taking one electrical cycle of the motor rotor as the basic period, and resampling the time-domain torque error that varies with time as a function of an interpolation algorithm based on the rotor position into a spatial domain torque error that varies with spatial position.

[0024] Specifically, after acquiring data for one rotational electrical cycle, a torque error-rotor position lookup table is established to achieve the following: Figure 2 , Figure 3 The time-domain to spatial-domain transformation is shown, where the torque error-rotor position lookup table is an array of length N. When creating the table, it can be based on the formula... Calculating the rotor position at position index k requires considering that the rotor position at sampling time t may not be exactly equal to the theoretical angle during the transformation process. Therefore, linear interpolation is performed on the torque error at different sampling times and the rotor position corresponding to the position index to map the instantaneous torque error to a fixed spatial index point.

[0025] S2, based on the torque error-rotor position comparison table, the spatial domain torque compensation table is iteratively updated.

[0026] For example, the spatial domain torque compensation scale is updated using the following formula:

[0027] in, This represents the torque compensation amount at the k-th index position in the updated spatial domain voltage compensation table. This represents the torque compensation amount at the k-th index position in the spatial domain voltage compensation table before the update. This represents the torque error at the k-th index position in the torque error-rotor position lookup table. N represents the length of the spatial domain voltage compensation scale; Q represents the forgetting factor, with a range of This enhances system stability and prevents overcompensation; G represents the learning gain, used to control the convergence speed, and its range can be [value missing]. .

[0028] Specifically, after the first rotating electrical cycle is completed, the obtained torque error-rotor position lookup table can be stored as an initial spatial domain torque compensation table, such as in the spatial repetitive controller used to execute the method of this invention. After the second rotating electrical cycle is completed, the stored spatial domain torque compensation amount can be iteratively updated using the above formula based on the currently obtained torque error-rotor position lookup table. The corresponding system block diagram is as follows: Figure 4 As shown.

[0029] In some embodiments of the present invention, the motor torque ripple suppression method further includes: when the time-domain torque error is detected to be greater than or equal to the error threshold, pausing the iterative update of the spatial domain torque compensation table; and resuming the iterative update of the spatial domain torque compensation table when the time-domain torque error is detected to be less than the error threshold.

[0030] Specifically, during motor acceleration / deceleration or sudden load changes, the torque error increases sharply. To avoid impacting system stability and accuracy, a dynamic threshold (i.e., an error threshold, which can be calibrated as needed) is set. When the detected real-time torque error signal exceeds this threshold, repetitive learning control (i.e., iterative updates) is paused, and pre-stored data is used to maintain motor operation. When the error falls below the threshold, repetitive control resumes, providing dynamic protection for the motor. Therefore, by introducing a threshold judgment mechanism based on instantaneous torque error, pausing updates during sudden speed or load changes prevents erroneous updates and enhances system stability.

[0031] S3. Based on the real-time rotor position, query the updated spatial domain torque compensation table to obtain the torque compensation signal.

[0032] In one embodiment, the torque compensation signal is obtained by querying the updated spatial domain torque compensation table based on the real-time rotor position, including: through the formula Calculate the index position corresponding to the real-time rotor position, where, Indicates the index position. The index indicates the real-time rotor position, and N represents the length of the spatial domain torque compensation table. The torque compensation signal is obtained by querying the updated spatial domain torque compensation table based on the index position, or by calculating the torque compensation signal through linear interpolation based on the query result.

[0033] S4 performs torque compensation control on the motor based on the torque compensation signal.

[0034] For example, torque compensation control of the motor based on the torque compensation signal includes: converting the torque compensation signal into a q-axis current compensation amount and superimposing the q-axis current compensation amount onto a q-axis current reference value; performing PI control based on the superimposed q-axis current reference value, which can achieve closed-loop suppression of torque ripple, and this process is a control that maps the torque compensation signal back to the time domain.

[0035] The torque compensation signal can be converted into the q-axis current compensation amount using the formula “q-axis current compensation amount = torque compensation signal / K_t”, where K_t is the torque constant of the motor.

[0036] This motor torque ripple suppression method continuously reduces torque error by iteratively updating the spatial domain torque compensation table through repetitive spatial domain control. Based on the updated spatial domain torque compensation table, a torque compensation signal is determined, and then the motor is controlled according to this signal to suppress torque ripple. This reduces electromagnetic noise, improves power output smoothness, and enhances the driving experience. Furthermore, spatial domain control solves the problem that traditional time-domain repetitive control cannot adapt to changes in motor speed, making it suitable for a wide operating speed range.

[0037] In some embodiments of the present invention, before querying the updated spatial domain torque compensation table according to the index position, the method further includes: calculating the required phase lead compensation angle based on the estimated system control delay time, for example, phase lead compensation angle = system control delay time × ω_e, that is, how many electrical angles ω_e the rotor has rotated ahead in space during the system control delay time; calculating the index lead amount L according to the phase lead compensation angle Φ and the length N of the spatial domain torque compensation table, such as... , This represents a rounding function; it uses the index lead time L to represent the index position. Perform corrections, such as mod represents the modulo operation.

[0038] Specifically, when converting the torque error from the spatial domain to the time domain, a phase difference may exist between the torque compensation signal and the torque error due to the delay in the control system. Therefore, phase lead correction of the torque compensation signal is required. See [link to relevant documentation] for details. Figure 2 , Figure 3Based on the estimated system control delay time, the required phase lead compensation angle can be obtained, and the index position can be corrected based on this compensation phase angle. Then, the updated spatial domain torque compensation table is queried based on the corrected position index, and the final torque compensation signal can be obtained by linear interpolation.

[0039] In some embodiments of the present invention, the motor torque ripple suppression method further includes: increasing the phase lead compensation angle by a preset step size in multiple consecutive electrical cycles; running torque compensation control at each phase lead compensation angle and recording the sum of the absolute values ​​of torque errors in one electrical cycle; stopping the search when the summation result changes from decreasing to increasing, and determining the phase lead compensation angle corresponding to the minimum value as the optimal value for subsequent control.

[0040] Specifically, while performing torque compensation control, the optimal phase lead compensation angle is also calculated to ensure phase matching between the compensation signal and the error signal. The process includes: constructing an initial spatial domain torque compensation scale in the first electrical cycle without compensation; starting from the second electrical cycle, increasing the phase lead compensation angle by a step size each cycle, recording the torque error at each phase, and summing the absolute values. This sum of absolute values ​​represents the effect of repeated control at this compensation phase. When the sum of absolute values ​​increases from small to large, the search stops, and the phase corresponding to the minimum value is the optimal phase lead compensation angle, which is then fixed for subsequent control. Thus, by dynamically optimizing the compensation phase corresponding to the system delay through an online self-search algorithm, the best suppression effect can be automatically ensured.

[0041] In summary, the motor torque ripple suppression method of this invention can suppress motor torque ripple, reduce electromagnetic noise, optimize power output smoothness, and improve the driving experience for passengers. Furthermore, by using spatial domain control, it solves the problem that traditional time-domain repetitive control cannot adapt to changes in motor speed, making it suitable for a wide operating speed range. By introducing a threshold judgment mechanism based on instantaneous torque error, repeated learning is paused when there are sudden changes in speed or load, preventing erroneous updates and enhancing system stability. Finally, by dynamically optimizing the compensation phase corresponding to the system delay through an online self-search algorithm, the optimal suppression effect is automatically ensured.

[0042] Figure 5 This is a structural block diagram of the controller according to an embodiment of the present invention.

[0043] like Figure 5 As shown, the controller 500 includes a processor 501 and a memory 503. The processor 501 and the memory 503 are connected, for example, via a bus 502. Optionally, the controller 500 may also include a transceiver 504. It should be noted that in practical applications, the transceiver 504 is not limited to one, and the structure of the controller 500 does not constitute a limitation on the embodiments of the present invention.

[0044] Processor 501 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this invention. Processor 501 may also be a combination that implements computational functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.

[0045] Bus 502 may include a pathway for transmitting information between the aforementioned components. Bus 502 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. Bus 502 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 5 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0046] The memory 503 stores a computer program corresponding to the motor torque ripple suppression method of the above embodiments of the present invention. This computer program is controlled and executed by the processor 501. The processor 501 executes the computer program stored in the memory 503 to implement the content shown in the foregoing method embodiments.

[0047] Among them, controller 500 can be the aforementioned spatial repeating controller. Figure 5 The controller 500 shown is merely an example and should not be construed as limiting the functionality and scope of use of embodiments of the present invention.

[0048] Based on the controller 500 of the above embodiments, the present invention also proposes a vehicle.

[0049] In this embodiment, the vehicle includes a motor and a controller 500.

[0050] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0051] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0052] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, 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 may be combined in any suitable manner in one or more embodiments or examples.

[0053] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to 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 this invention.

[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0055] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0056] In this invention, 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," "over," and "on top" of 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 "beneath" of 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.

[0057] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method of suppressing torque pulsation of an electric motor, characterized by, The method comprises: collecting time-domain torque error of the motor in time domain, and mapping the time-domain torque error to a space domain associated with rotor position of the motor to obtain a torque error-rotor position table; iteratively updating a space-domain torque compensation table based on the torque error-rotor position table; querying the updated space-domain torque compensation table according to real-time rotor position to obtain a torque compensation signal; controlling torque compensation of the motor according to the torque compensation signal.

2. The motor torque ripple suppression method according to claim 1, characterized by, The mapping of the time-domain torque error to the space domain associated with the rotor position of the motor comprises: taking one electrical period of rotation of the rotor as a basic period, and resampling the time-varying time-domain torque error into space-domain torque error varying with spatial position through an interpolation algorithm according to rotor position.

3. The motor torque ripple reduction method of claim 1, wherein The space-domain torque compensation table is updated by the following formula: wherein, represents a torque compensation amount of the kth index position in the updated space domain voltage compensation table, represents a torque compensation amount of the kth index position in the pre-updated space domain voltage compensation table, represents a torque error of the kth index position in the torque error-rotor position table, N represents a length of the space domain voltage compensation table, Q represents a forgetting factor, and G represents a learning gain.

4. The motor torque ripple reduction method of claim 2, wherein The querying of the updated space-domain torque compensation table according to real-time rotor position to obtain a torque compensation signal comprises: calculating an index position corresponding to the real-time rotor position by the following formula: wherein, denotes the index position, denotes the real-time rotor position, N denotes the length of the space-domain torque compensation scale; querying the updated space-domain torque compensation table according to the index position to obtain the torque compensation signal, or calculating the torque compensation signal through linear interpolation based on the query result.

5. The motor torque ripple reduction method of claim 4, wherein, Before the querying of the updated space-domain torque compensation table according to the index position, the method further comprises: calculating a required phase lead compensation angle based on an estimated system control delay time; calculating an index lead amount according to the phase lead compensation angle and the length of the space-domain torque compensation table; and correcting the index position by using the index lead amount.

6. The motor torque ripple reduction method of claim 5, wherein The method further comprises: increasing the phase lead compensation angle by a preset step size within a plurality of consecutive electrical periods; running torque compensation control under each phase lead compensation angle, and recording the sum of absolute values of torque error within one electrical period; when the sum result is monitored to change from falling to rising, stopping the search, and determining the phase lead compensation angle corresponding to the minimum value as an optimal value for subsequent control.

7. The motor torque ripple mitigation method of claim 1, wherein, The torque compensation control of the motor according to the torque compensation signal comprises: converting the torque compensation signal into q-axis current compensation, and superimposing the q-axis current compensation on the q-axis current reference value; performing PI control based on the superimposed q-axis current reference value.

8. The motor torque ripple mitigation method of claim 1, wherein, The method further comprises: suspending the iterative updating of the space-domain torque compensation table when the time-domain torque error is detected to be greater than or equal to an error threshold value; resuming the iterative updating of the space-domain torque compensation table when the time-domain torque error is detected to be less than the error threshold value.

9. A controller comprising a memory, a processor, and a computer program stored on the memory, wherein, The computer program, when executed by the processor, implements the motor torque ripple suppression method according to any one of claims 1-8.

10. A vehicle characterized by comprising: The controller according to claim 9.

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