A method and system for controlling a motor drive to reduce torque ripple
By acquiring motor signals in real time and using complex exponential basis functions and learning rates for current compensation, the problem of torque pulsation caused by operating condition drift in traditional motor driver control is solved, achieving the effect of reducing torque harmonics and improving the real-time performance and accuracy of motor control.
Patent Information
- Application Number
- CN202511430891.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-09
- Publication Date
- 2025-12-23
- Estimated Expiration
- 2045-10-09
AI Technical Summary
Traditional motor drive control methods cannot track changes in operating conditions in real time, which leads to the need for recalibration to reduce torque ripple, increasing cost and complexity.
By collecting the phase current and electrical angle of the motor through sensors, and using complex exponential basis functions and learning rates to perform real-time compensation current calculations, torque pulsation is offset, and changes in operating conditions are tracked in real time to avoid repeated calibration.
Without adding sensors and hardware filters, it effectively reduces torque harmonic amplitude, tracks changes in operating conditions in real time, reduces costs, and improves control accuracy.
Smart Images
Figure CN120915177B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of motor control, in particular to a motor driver control method and system for reducing torque ripple. BACKGROUND
[0002] Torque ripple often occurs when the motor starts, runs at low speed or the load changes. Torque ripple refers to the additional torque component on the motor output shaft that fluctuates periodically over time. The sources include stator current harmonics, uneven permanent magnets, tooth slot effect, magnetic force sub-harmonic coupling, driver dead zone or power switch delay, etc. Torque ripple can cause motor vibration, noise, speed jitter and positioning error, resulting in reduced control accuracy and reduced service life of the motor. Therefore, it is necessary to reduce torque ripple in motor driver control.
[0003] Traditional methods usually first use finite element simulation to calibrate the amplitude and phase of torque ripple, and then use a lookup table or fixed feedforward method to superimpose the corresponding frequency harmonic current on the quadrature axis in the control program. However, this method does not take into account the condition drift that may occur during motor operation, such as temperature rise, demagnetization of magnetic steel or sudden load change. It can only be slowly corrected by recalibration or additional high-bandwidth PI / PIR loop, so multiple gains have to be set and a large current margin has to be reserved.
[0004] Therefore, in the motor driver control for reducing torque ripple, how to track the amplitude and phase drift caused by the change of working conditions in real time, and superimpose compensation on the torque ripple to solve the technical problem of re-calibration of traditional methods in condition drift is a problem that needs to be considered. SUMMARY
[0005] In order to solve the technical problem of re-calibration caused by drift, the present application provides a motor driver control method and system for reducing torque ripple, and the technical solution is as follows:
[0006] In a first aspect, the present application provides a motor driver control method for reducing torque ripple, which comprises the following steps:
[0007] The phase current and electrical angle of the motor at each time are collected by a sensor;
[0008] The torque signal of the motor is collected by a torque sensor, and the harmonic order based on the torque signal is selected as the torque ripple order. A sliding window at a preset time is set as a control period. The instantaneous torque estimate value at each time is determined based on the torque constant of the motor and the phase current at each time in the control period. The complex exponential signal corresponding to each torque ripple order is determined based on the electrical angle at each time and different torque ripple orders using a complex exponential basis function. The complex coefficient of the control period is determined based on the complex exponential signal at each time and the instantaneous torque estimate value.
[0009] Determine the electrical angular velocity based on the mechanical angular velocity and the number of pole pairs of the motor itself, determine the phase rotation factor combining the preset hysteresis time and the torque ripple order and the electrical angular velocity; map the complex coefficient to the current potential through the torque constant, then combine the phase rotation factor to obtain the compensation current by taking the real part of the complex number; the sum of the compensation current and the reference current is recorded as the final input current; the reference current is obtained through the torque ring;
[0010] Determine the on-trend torque residual based on the difference between the on-trend torque estimate value and the preset expected average torque; obtain the residual complex coefficient based on the instantaneous torque residual and the complex exponential signal in the control period; obtain the updated complex coefficient by the difference between the complex coefficient of the torque ripple order in the control period and the residual complex coefficient combined with the preset learning rate;
[0011] Take the updated complex coefficient as the complex coefficient of the next control period, and then obtain the final input current of the next control period, so as to control the motor.
[0012] In the above scheme, the present application uses the linear relationship between the motor torque and the cross-axis current in the framework of vector control, makes complex projection of the instantaneous torque in the electrical angular domain according to the target harmonic order, extracts the amplitude and phase of the harmonic of this order, converts the complex coefficient into the anti-phase cross-axis current injection current loop to offset the torque ripple. In order to cope with the deviation of the complex coefficient caused by the working condition drift, the residual torque after offsetting and the basis function are used again to do complex correlation, and a single learning rate is used to fine-tune the complex coefficient for the compensation current calculation of the next control period; its beneficial effects are that without increasing sensors and hardware filters, the amplitude of the torque harmonic is effectively reduced by using the existing current sampling and angle coding in the motor, which can reduce the cost; and it can also track the working condition changes in real time, avoiding the repeated calibration of traditional methods.
[0013] In one embodiment, the method for screening the harmonic order based on the torque signal is recorded as the torque ripple order:
[0014] Convert the torque signal of the motor into a frequency spectrum graph through fast Fourier transform, and extract the harmonic order of the electrical angle corresponding to the highest amplitude of the preset number of peaks in the frequency spectrum graph, which is recorded as the torque ripple order.
[0015] In one embodiment, the instantaneous torque estimate value is in a positive correlation with the torque constant and the phase current respectively, and the torque constant is directly obtained through the motor nameplate.
[0016] In one embodiment, the expression of the complex exponential signal is:
[0017] , indicates the torque ripple order, θt represents the electrical angle at the tth moment, j represents the imaginary unit, exp represents the exponential function with the natural constant as the base, exp(h, t) represents the complex exponential signal of the hth harmonic at the tth moment; the order of the hth harmonic is the order of the torque ripple.
[0018] In an embodiment, the expression of the complex coefficient is:
[0019] , θt represents the instantaneous torque estimation value at the tth moment, exp(h, t) represents the complex exponential signal of the hth harmonic at the tth moment, T represents the length of the control period, C(h) represents the complex coefficient corresponding to the hth harmonic of the control period.
[0020] In an embodiment, the method for determining the electrical angular velocity based on the mechanical angular velocity of the motor itself and the number of pole pairs, and determining the phase rotation factor in combination with the preset lag time and the order of the torque ripple and the electrical angular velocity is:
[0021] The product of the mechanical angular velocity and the number of pole pairs is taken as the electrical angular velocity;
[0022] The product of the electrical angle at each moment and the order of the torque ripple is denoted as a first product;
[0023] The product of the electrical angular velocity at each moment and the preset lag time is denoted as a second product;
[0024] The first product and the second product are taken as the complex unit, and then the phase rotation factor is obtained by calculating the exponential function.
[0025] In an embodiment, the method for mapping the complex coefficient to the current potential through the torque constant, and then obtaining the compensation current by taking the real part of the complex number in combination with the phase rotation factor is:
[0026] The ratio of the complex coefficient corresponding to the order of the torque ripple to the torque constant is taken as a negative number, the product of the negative number and the phase rotation factor is calculated, and the real part of the product is taken as the compensation current of the order of the torque ripple at each moment.
[0027] In an embodiment, the method for obtaining the residual complex coefficient based on the instantaneous torque residual and the complex exponential signal in the control period is:
[0028] The difference between the instantaneous torque estimation value at each moment and the preset expected average torque is denoted as a first difference;
[0029] The average of the products of the first differences at all moments in the control period and the complex exponential signals under the order of the torque ripple is taken as the residual complex coefficient.
[0030] In one embodiment, the updated complex coefficient is a difference between the complex coefficient of each control period and a product of a learning rate and a residual complex coefficient.
[0031] In a second aspect, the embodiments of the present application also provide a motor driver control system for reducing torque ripple, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the steps of the motor driver control method for reducing torque ripple according to any one of the above aspects when executing the computer program.
[0032] The beneficial effects of the present application are as follows:
[0033] In the framework of vector control, the present application uses the linear relationship between motor torque and quadrature axis current to make a complex projection of instantaneous torque in the electrical angle domain according to the target harmonic order, extracts the amplitude and phase of the harmonic of this order, converts the complex coefficient into a counter-phase quadrature axis current injection current loop to offset the torque ripple. In order to cope with the deviation of the complex coefficient caused by the working condition drift, the residual torque after offset and the basis function are used again to make a complex correlation, and a single learning rate is used to fine-tune the complex coefficient for the compensation current calculation of the next control period. Without increasing sensors and hardware filters, the present application effectively reduces the amplitude of torque harmonics using the existing current sampling and angle coding in the motor, which can reduce the cost, and can also track the working condition changes in real time to avoid repeated calibration of traditional methods. BRIEF DESCRIPTION OF DRAWINGS
[0034] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the drawings needed in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.
[0035] Figure 1 A flowchart of a motor driver control method for reducing torque ripple is provided in one embodiment of the present application. DETAILED DESCRIPTION
[0036] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific embodiments, structure, features and effects of the motor driver control method and system according to the present application are described in detail as follows in combination with the drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.
[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
[0038] A motor driver control method embodiment for reducing torque ripple:
[0039] The specific scheme of the motor driver control method for reducing torque ripple provided by the application will be described in detail below with reference to the drawings.
[0040] Please refer to Figure 1 , which shows a flow chart of a motor driver control method for reducing torque ripple provided by an embodiment of the application, which comprises the following steps:
[0041] Step S001, collect phase current and electrical angle.
[0042] The motor is linked with the inverter for converting the DC bus voltage into three-phase AC voltage to drive the motor. The motor used in the application can be a permanent magnet synchronous motor (PMSM), a brushless direct current motor (BLDC) or a motor using vector control / magnetic field oriented control.
[0043] The phase current of the motor is collected by the sensor, and under the control of the electrical signal of the motor, the motor rotor rotates a certain angle, which is the electrical angle, which is represented as the phase difference on the electrical signal. An electrical period is the time for one pair of magnetic poles to rotate one circle. In this embodiment, the sampling frequency of the phase current and the electrical angle is 10 kHz.
[0044] At this point, the phase current and the electrical angle of the motor at each time are obtained.
[0045] Step S002, based on the torque signal, the harmonic order is selected as the torque ripple order, the torque estimate value is determined based on the phase current and the torque constant within the control period; the complex exponential signal is determined by the electrical angle and the complex exponential base function of the torque ripple order, and the complex coefficient is determined by combining the instantaneous torque estimate value.
[0046] Since the torque ripple usually repeats with the electrical angle as the period, and the main energy is concentrated in the low-order harmonics, the amplitude and phase information of the order can be extracted as the complex coefficient by using the complex exponential base function of the target order and the instantaneous torque correlation, which can not only separate the noise and other orders, but also smooth the sampling error.
[0047] Specifically, in the application, a sliding window at a preset time is set, each sliding window is taken as a control period, and the complex coefficient of each harmonic order is determined based on the instantaneous torque estimate value and the complex exponential base function at all times within the control period; wherein the function value corresponding to the complex exponential base function is recorded as the complex exponential signal.
[0048] The torque signal of the motor is collected by a torque sensor, and the torque signal of the motor is converted into a frequency spectrum diagram by fast Fourier transform, and the harmonic order of the electrical angle corresponding to the highest amplitude of the preset number of peaks in the frequency spectrum diagram is recorded as the torque pulsation order.
[0049] In the control period, the instantaneous torque estimation value at each moment is determined by the torque constant of the motor and the phase current at each moment.
[0050] The instantaneous torque estimation value is positively correlated with the torque constant and the phase current, respectively.
[0051] It should be noted that positive correlation means that when one variable increases, the other variable also increases, and the two variables change in the same direction. When one variable changes from large to small or from small to large, the other variable also changes from large to small or from small to large. The specific relationship is determined by actual application, and the present application does not make special limitations.
[0052] Preferably, in the present embodiment, the expression of the instantaneous torque estimation value is:
[0053] , represents the torque constant of the motor, represents the phase current at the tth moment, represents the instantaneous torque estimation value at the tth moment. It should be noted that the torque constant is an inherent parameter of the motor, which is obtained through the motor nameplate.
[0054] The complex exponential signal is determined by the electrical angle at each moment and the harmonic order corresponding thereto.
[0055] Preferably, in the present embodiment, the expression of the complex exponential signal is:
[0056] , represents the torque pulsation order, represents the electrical angle at the tth moment, represents the imaginary unit, represents the exponential function with the natural constant as the base, represents the complex exponential signal of the hth order harmonic at the tth moment; the order of the hth order harmonic is the torque pulsation order.
[0057] The complex exponential signal is a unit complex vector that rotates with the electrical angle. When it is used as a coherent reference clock in the electrical angle domain, only the harmonic component with the same frequency as it can be converted into a direct current complex after being multiplied by it, and the remaining components are moved to non-zero frequency and filtered out in the sliding average.
[0058] The complex coefficient of the control period is determined based on the complex exponential signal and the instantaneous torque estimation value at each moment obtained above.
[0059] The complex coefficient is expressed as:
[0060] represents the instantaneous torque estimation value at the tth moment, represents the complex exponential signal of the hth order harmonic at the tth moment, represents the length of the control period, represents the complex coefficient corresponding to the control period hth order harmonic. It is worth noting that the number 2 represents a Fourier series amplitude normalization factor, which ensures that the amplitude of the complex coefficient is directly equal to the actual amplitude of the order harmonic.
[0061] Because the components of the torque ripple of each order and the electrical angle are in an integer frequency relationship, the instantaneous torque estimation value is multiplied by the function value of the corresponding complex exponential base function and the sliding window average is taken, which is equivalent to coherent demodulation of the target order, the same frequency components are coherently accumulated, and other orders and broadband noise are mutually canceled in the average process due to the orthogonality, thereby extracting the amplitude and phase of the hth order harmonic to the complex coefficient, realizing high signal-to-noise ratio feature extraction.
[0062] At this point, the complex coefficients of different harmonic orders are obtained.
[0063] In step S003, the phase rotation factor is determined by the lag time, the electrical angular velocity, and the torque ripple order, the compensated current is obtained by combining the mapped complex coefficient, and the final input current is obtained.
[0064] Because the electromagnetic torque is in a linear proportional relationship with the phase current in vector control, the obtained complex coefficient is converted into a current component of the same amplitude and opposite direction and is superimposed on the original reference current in real time, so that the inverter can generate an electromagnetic torque equal in size and opposite in direction to the harmonic torque at the motor end in the next control period without additional hardware, thereby eliminating the harmonic torque of the order and making only a small correction to the motor cross axis without affecting the average torque and flux linkage.
[0065] According to the above analysis, the current finally sent to the current loop is the current after superimposed compensation on the reference current, so the reference current and the compensation current need to be obtained. The reference current is obtained through the torque loop.
[0066] Therefore, the complex coefficient is mapped to the current unit, but in order to maintain a strict inverse relationship between the injected current and the real harmonic torque, the delay caused by the system timing needs to be considered, otherwise the compensation current may lag behind the harmonic torque, causing partial cancellation or even reverse amplification. Therefore, the phase rotation factor is determined by the electrical angle of different harmonic orders and the lagged electrical angle, and the complex coefficient mapped to the current unit is expanded to the time domain based on the current electrical angle based on the phase rotation factor.
[0067] By the above analysis, the phase rotation factor is determined based on the electrical angle and the hysteresis time and the electrical angular velocity.
[0068] Preferably, the expression of the phase rotation factor is:
[0069] denotes the order of the torque ripple, denotes the electrical angle at the tth moment, denotes the electrical angular velocity at the tth moment, denotes the hysteresis time, denotes the imaginary unit, denotes the exponential function with the natural constant as the base, denotes the phase rotation factor of the hth order harmonic. The hysteresis time is the fixed time lag caused by the update link between the moment of calculating the instantaneous torque estimate and the moment of the action of the estimate; the electrical angular velocity is obtained by the product of the mechanical angular velocity and the pole pair number of the motor, wherein the mechanical angular velocity and the pole pair number are both known parameters of the motor.
[0070] The compensation current is obtained by mapping the complex coefficient to the current potential through the torque constant, combining the phase rotation factor, and taking the real part of the complex number.
[0071] Preferably, in the embodiment, the expression of the compensation current is:
[0072] denotes the complex coefficient corresponding to the hth order harmonic of the control period, denotes the torque constant of the motor, denotes the phase rotation factor of the hth order harmonic, denotes the real part of the complex number, denotes the compensation current of the hth order harmonic at the tth moment.
[0073] The sum of the compensation current and the reference current at each moment is recorded as the final input current, and the final input current is injected into the current loop, so as to offset the torque ripple of the hth order harmonic.
[0074] Step S004, based on the torque residual and the complex exponential signal, the residual complex coefficient is obtained, and the difference between the original complex coefficient and the updated complex coefficient is determined after combining the learning rate.
[0075] During the operation of the motor, the working condition may drift due to temperature rise, demagnetization of the magnetic steel or sudden change of the load, which may cause a certain difference in amplitude and phase between the harmonic complex coefficients obtained in the above steps and the complex coefficients for obtaining the compensation current. If only one-time injection is performed, it is difficult to completely eliminate the harmonics, and the measurement noise may be introduced into the system or over-compensation may be caused, resulting in torque ripple rebound or even control loop vibration. Therefore, an online adaptive mechanism needs to be introduced, the instantaneous torque residual is taken as feedback, the residual error of the order is extracted through complex correlation operation with the electrical angle base function, and the complex coefficient is fine-tuned with a single learning rate, so that the compensation amount converges to the optimal value in real time according to the working condition, thereby ensuring fast response while eliminating long-term deviation and noise accumulation, and achieving stable suppression of torque ripple in all control periods.
[0076] Through the above analysis, first, the instantaneous torque residual is determined based on the difference between the instantaneous torque estimation value at each moment and the expected average torque; wherein the expected average torque is the steady-state average torque output by the motor, which is directly given by the speed loop.
[0077] Based on the instantaneous torque residual and the negative exponential signal in the control period, the residual complex coefficient is obtained, the difference between the complex coefficient of each harmonic order in the control period and the residual complex coefficient combined with the learning rate is obtained to obtain the updated complex coefficient, and the updated complex coefficient is taken as the complex coefficient of the current compensation in the next control period.
[0078] Preferably, in the embodiment, the expression for updating the complex coefficient is:
[0079] represents the instantaneous torque estimation value at the t th moment, represents the expected average torque at the t th moment, represents the complex exponential signal of the h th harmonic at the t th moment, represents the length of the control period, represents the learning rate, represents the complex coefficient corresponding to the h th harmonic in the k th control period, represents the complex coefficient corresponding to the h th harmonic in the k+1 th control period.
[0080] The learning rate determines the correction amplitude of the complex coefficient according to the residual at each step, the larger the value, the faster the convergence, that is, the new working condition can be caught up in a shorter period, but noise may be introduced, which may easily lead to oscillation; the smaller the value, the slower the convergence, which may not be able to keep up with the working condition change. In the present application, the learning rate is determined by the window length L, because the window length determines the noise attenuation of the average link, so the larger the L, the greater the noise attenuation, The larger the value, the faster the convergence, and vice versa. The value of L is in the range of In the embodiment, the value of the hth order complex exponential basis function .
[0081] The residual harmonic error vector is obtained by projecting the instantaneous torque residual on the hth order complex exponential basis function, because in the electrical angle domain, any signal with a period of electrical angle can be regarded as the superposition of a set of orthogonal harmonics, and the hth order complex exponential basis function is the inner product basis of the hth order, if the hth order harmonic component still exists in the instantaneous torque residual, it will be correlated with the basis function, and after multiplication, they will not cancel each other in the average sense, but will be extracted as a complex coefficient, the direction and size of the complex number is the error vector of the residual harmonic, that is, the amplitude and phase error direction, and other components orthogonal to the basis function tend to zero due to statistical averaging, and will not interfere with the direction. A small learning rate is used for updating, which can slightly correct the amplitude and phase at the same time, so that the residual harmonic energy can gradually converge to the global minimum, while avoiding introducing too much noise. The compensation current obtained from the complex coefficient can offset more harmonics and avoid introducing noise.
[0082] At this point, the update of the complex coefficient is completed.
[0083] In step S005, the final input current of the next control period is obtained based on the updated complex coefficient to complete motor control.
[0084] The updated complex coefficient is taken as the complex coefficient of the next control period and brought into the expression of the compensation current to obtain the compensation current corresponding to the control period, which is input into the current loop to offset the torque ripple of the harmonics, obtain the final input current, and then control the motor.
[0085] Based on the same inventive concept as the above method, the embodiments of the present application also provide a motor driver control system for reducing torque ripple, which comprises a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the steps of any one of the above motor driver control methods for reducing torque ripple when executing the computer program.
[0086] It should be noted that: the above-mentioned embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.
[0087] The various embodiments described in this specification are presented by way of example, and each embodiment is not inherently more important than any other embodiment.
Claims
1. A motor drive control method for reducing torque ripple, characterized by, The method comprises the following steps: Collecting the phase current and the electrical angle of the motor at each moment through a sensor; Collecting the torque signal of the motor through a torque sensor, and screening the harmonic order based on the torque signal, which is recorded as the torque ripple order; setting a sliding window at a preset moment as a control period; determining the instantaneous torque estimation value at each moment based on the torque constant of the motor and the phase current at each moment in the control period; determining the complex exponential signal corresponding to each torque ripple order based on the electrical angle at each moment and the different torque ripple orders; determining the complex coefficient of the control period based on the complex exponential signal at each moment and the instantaneous torque estimation value; Determining the electrical angular velocity based on the mechanical angular velocity and the number of pole pairs of the motor itself, and determining the phase rotation factor in combination with the preset lag time and the torque ripple order and the electrical angular velocity; mapping the complex coefficient to the current potential through the torque constant, and then taking the real part of the complex number to obtain the compensation current in combination with the phase rotation factor; taking the sum of the compensation current and the reference current as the final input current; the reference current is obtained through the torque loop; Determining the on-trend torque residual error based on the difference between the on-trend torque estimation value and the preset expected average torque; obtaining the residual complex coefficient based on the instantaneous torque residual error and the complex exponential signal in the control period; obtaining the updated complex coefficient based on the difference between the complex coefficient of the torque ripple order in the control period and the residual complex coefficient in combination with the preset learning rate; Taking the updated complex coefficient as the complex coefficient of the next control period, and then obtaining the final input current of the next control period, so as to control the motor.
2. A method of controlling a motor drive to reduce torque ripple as claimed in claim 1, wherein, The method for screening the harmonic order based on the torque signal is recorded as the torque ripple order: Converting the torque signal of the motor into a frequency spectrum diagram through fast Fourier transform, and extracting the harmonic order of the electrical angle corresponding to the highest amplitude of the preset number of sharp peaks in the frequency spectrum diagram as the torque ripple order.
3. The motor drive control method of claim 1, wherein, The instantaneous torque estimation value is positively correlated with the torque constant and the phase current, and the torque constant is directly obtained through the motor nameplate.
4. The motor drive control method of reducing torque pulsation according to claim 1, characterized by, The expression of the complex exponential signal is: , denotes the order of torque ripple, denotes the electrical angle at the t-th time instant, denotes the imaginary unit, denotes the exponential function with base of the natural constant, denotes the complex exponential signal of the h-th harmonic at the t-th time instant; the order of the h-th harmonic is the order of torque ripple.
5. The method of claim 1, wherein the step of determining the torque command comprises the step of: determining the torque command based on the torque demand, the motor speed, and the motor current. The expression of the complex coefficient is: , represents an instantaneous torque estimate at the tth time instant, represents a complex exponential signal of the hth harmonic at the tth time instant, represents the length of a control period, represents a complex coefficient corresponding to the hth harmonic of the control period.
6. The motor drive control method of reducing torque pulsation according to claim 1, wherein The method for determining the electrical angular velocity based on the mechanical angular velocity and the number of pole pairs of the motor itself, and determining the phase rotation factor in combination with the preset lag time and the torque ripple order and the electrical angular velocity is: Taking the product of the mechanical angular velocity and the number of pole pairs as the electrical angular velocity; Taking the product of the electrical angle at each moment and the torque ripple order as the first product; Taking the product of the electrical angular velocity at each moment and the preset lag time as the second product; Taking the complex unit of the first product and the second product, and then obtaining the phase rotation factor through the exponential function calculation.
7. The method of claim 1, wherein the step of determining the torque command comprises the step of: determining the torque command based on the torque demand, the torque ripple, and the motor speed. The method for mapping the complex coefficient to the current potential through the torque constant, and then taking the real part of the complex number to obtain the compensation current in combination with the phase rotation factor is: Taking the negative of the ratio of the complex coefficient corresponding to the torque ripple order to the torque constant, calculating the product of the negative and the phase rotation factor, and taking the real part of the product as the compensation current of the torque ripple order at each moment.
8. The method of claim 1, wherein the step of determining the torque command comprises the step of: determining the torque command based on the torque demand, the torque ripple, and the motor speed. The method for obtaining the residual complex coefficient based on the instantaneous torque residual error and the complex exponential signal in the control period is: Calculating the difference between the instantaneous torque estimation value at each moment and the preset expected average torque as the first difference; The mean of the product of the first difference at all time instants in a control period and the complex exponential signal at the torque ripple order is taken as a residual complex coefficient.
9. The method of claim 1, wherein the step of determining the torque command comprises the step of: determining the torque command based on the torque demand, the torque ripple, and the motor speed. The updated complex coefficient is the difference between the complex coefficient of each control period and the product of the learning rate and the residual complex coefficient.
10. A motor drive control system for reducing torque ripple, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, The processor realizes the steps of the motor driver control method for reducing torque ripple according to any one of claims 1-9 when executing the computer program.
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