A high-speed brushless direct current motor torque ripple suppression method, device, equipment and storage medium

Abstract

The application discloses a high-speed brushless direct-current motor torque ripple suppression method, device, equipment and storage medium, and belongs to the motor control technical field.The method contains three steps: adaptive harmonic suppression processing, phase compensation angle calculation and dynamic phase compensation.The application dynamically adjusts the center frequency through the adaptive harmonic trap filter, suppresses the dominant harmonic component in real time, combines with the cascade delay signal elimination, filters out the 6k fixed harmonic through the CDSC filter, and obtains a fundamental current signal;Park transformation is carried out on the fundamental current based on the FOC algorithm, a phase delay angle is generated according to the d-axis current error through the PI controller, and the current reference value is dynamically compensated through the reference current compensation module, so that the phase current and the back electromotive force are guaranteed to be in phase synchronization.Compared with the prior art, the application does not need additional hardware equipment, and reduces the BLDC torque ripple.

Description

Technical Field

[0001] This invention belongs to the field of motor control technology, specifically relating to a method, apparatus, and storage medium for suppressing torque ripple in a high-speed brushless DC motor based on adaptive harmonic suppression and dynamic phase compensation. Background Technology

[0002] Brushless DC motors (BLDC) are widely used in many high-speed applications, such as compressors, blowers, and drilling machines, due to their high torque density, high efficiency, and high reliability. Figure 1 As shown, the BLDC system includes a brushless DC motor 1 and an inverter 2. Existing six-step conduction control methods typically require six discrete commutation points:

[0003] AB is powered on: S1 and S4 are open.

[0004] AC power on: S1 and S6 are open.

[0005] bc is powered on: S3 and S6 are turned on.

[0006] BA is powered on: S3 and S2 are open.

[0007] CA powered on: S5 and S2 open

[0008] cb is powered on: S5 and S4 are turned on.

[0009] Inverter 2 is triggered to commutate every 60 electrical degrees, enabling DC power to supply power to brushless DC motor 1. Three Hall effect sensors H are also installed on the stator of brushless DC motor 1. A H B H C This is used to detect the spatial angle of the rotor of a brushless DC motor on its circumference. However, phase delay errors typically exist during commutation, causing the phase current and back electromotive force to misalign, resulting in significant torque ripple in the BLDC motor. At high speeds, the main cause of phase delay errors in BLDC motors is the hysteresis effect of the motor coil inductance, causing the phase current to lag behind the back electromotive force. Furthermore, at high speeds, the phase current is highly prone to generating high-order harmonics, making the calculation of phase delay errors difficult.

[0010] Traditional methods rely on zero-point commutation based on back EMF. Since the phase current lags behind the back EMF, an advance angle is needed to compensate for the current delay caused by inductance, synchronizing the input motor phase current with the back EMF and resulting in a smoother motor output torque. Existing methods for eliminating phase delay are mainly divided into open-loop compensation and closed-loop compensation. Open-loop compensation compensates for phase delay by advancing the commutation angle or using model prediction, but its accuracy is highly dependent on the precise calibration of motor parameters and is sensitive to nonlinear effects such as inductor temperature rise and magnetic saturation, leading to a long dynamic response time and difficulty in adapting to high-speed transient changes. Closed-loop compensation mainly relies on a phase-locked loop (PLL) to track the back EMF phase. However, harmonic interference at high speeds can easily cause PLL lockout, and the phase difference between the inherent oscillation wave and the input signal in a PLL is limited. Furthermore, it requires a high-precision encoder or additional sensors, significantly increasing hardware costs. Summary of the Invention

[0011] To address the problems existing in the prior art, the technical problem to be solved by the present invention is to provide a method, device, equipment and storage medium for suppressing torque ripple in high-speed brushless DC motors. It suppresses broadband harmonic interference in real time through dual-stage harmonic filtering and dynamically corrects phase error by combining d-axis current feedback, thereby solving the problem of phase delay of phase current and back electromotive force caused by inductive hysteresis and harmonic pollution under high-speed operating conditions and reducing the torque ripple of the motor.

[0012] In a first aspect, embodiments of the present invention provide a method for suppressing torque ripple in a high-speed brushless DC motor, comprising the following steps:

[0013] Step 1: Adaptive Harmonic Suppression Processing

[0014] Acquiring the three-phase current signal I of a brushless DC motor a I b I c The adaptive harmonic notch filter and CDSC filter are used to suppress the dominant harmonic components in the three-phase current in real time. The adaptive harmonic notch filter dynamically adjusts the center frequency of the notch filter based on the gradient descent algorithm to track and filter out the target harmonic components. The processed signal is input into the CDSC filter, and through the superposition and subtraction of N-stage cascaded delay units, the 6k fixed harmonics are filtered out, k = 1, 2, ..., N, to obtain the fundamental current signal I. a1 I b1 I c1 ;

[0015] Step 2: Calculation of phase compensation angle based on FOC algorithm

[0016] The fundamental current signal I after filtering in step 1 a1 I b1 I c1Perform a Park transform to convert the fundamental current signal from the stationary reference frame to the synchronous reference frame, and obtain the d-axis current I. d and q-axis current I q ;

[0017] Reference current I along the d-axis dref Obtain the d-axis current error I e =I dref -I d , with I e As input, a phase delay angle Δθ is generated by a PI controller. The formula for calculating this phase delay angle is:

[0018] Δθ=K p ·I e +K i ∫I e dt

[0019] In the formula, K p K is the proportionality coefficient. i The integral coefficient;

[0020] Step 3: Dynamic phase compensation based on FOC algorithm

[0021] The phase delay angle Δθ is used by the reference current compensation module to generate compensation amount ΔI for the d-axis and q-axis current reference values. d ΔI q for:

[0022] ΔI d =-K d ·Δθ、ΔI q =K q ·Δθ

[0023] In the formula, ΔI d The magnitude of the d-axis reference current compensation is ΔI. q K represents the magnitude of the q-axis reference current compensation. d K q It is to compensate for the gain;

[0024] The compensated current reference value The input FOC current loop is used, and after the Park inverse transformation is completed inside the current loop, the three-phase voltages Va, Vb, and Vc are calculated. The PWM generator adjusts the duty cycle according to the three-phase voltage to generate a PWM drive signal, so that the real-time phase delay Δθ of the phase current relative to the back EMF approaches 0, thereby achieving phase synchronization between the phase current and the back EMF.

[0025] Secondly, embodiments of the present invention provide a high-speed brushless DC motor torque ripple suppression device, comprising the following parts:

[0026] An adaptive harmonic notch filter is used to receive three-phase current signals, identify the dominant harmonic frequencies, and dynamically update the notch filter center frequency according to the objective function. It employs a second-order IIR structure to perform real-time filtering, suppressing and trapping harmonics.

[0027] Target harmonics with the same center frequency as the waveguide;

[0028] The CDSC filter is used to receive current data processed by the adaptive harmonic notch filter. It performs superposition or subtraction operations on the current through N-stage series delay units to filter out the 6k fixed harmonics in the current signal, obtaining the final fundamental current signal I. a1 I b1 I c1 ;

[0029] The Park transform unit is used to convert the fundamental current signal from the stationary reference frame to the synchronous reference frame to obtain the d-axis current I. d and q-axis current I q ;

[0030] The comparator is used to convert the d-axis current I in a synchronous reference frame. d With the target reference current I dref By comparison, the current error I along the d-axis is calculated. e =I dref -I d ;

[0031] PI controller, using I e The input is used to generate the phase delay angle Δθ;

[0032] The reference current compensation module is used to generate compensation amounts for the d-axis and q-axis current reference values ​​from the phase delay angle Δθ, thus obtaining the compensated current reference value I. d * and I q * ;

[0033] The FOC current loop is used to convert the compensated current reference value I... d * and I q * Calculate the dq voltage V d V q The dq voltage is converted into three-phase voltages Va, Vb, and Vc by performing an inverse Park transformation. The PWM generator adjusts the duty cycle according to the three-phase voltage to generate PWM drive signals, so that the real-time phase delay Δθ of the phase current relative to the back electromotive force approaches 0.

[0034] Thirdly, embodiments of the present invention provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the electronic device enables the high-speed brushless DC motor torque ripple suppression method provided in any of the embodiments herein.

[0035] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing a computer program that, when executed by a computing device, causes the computing device to implement any of the high-speed brushless DC motor torque ripple suppression methods described in the embodiments herein.

[0036] The technical advantages of this invention are: it achieves the suppression of BLDC torque ripple, improves the performance of BLDC operation, and does not require additional hardware. Attached Figure Description

[0037] The accompanying drawings of this invention are described below:

[0038] Figure 1 This is a circuit diagram of a high-speed brushless DC motor inverter.

[0039] Figure 2 This is a flowchart of a method according to one embodiment;

[0040] Figure 3 This is a schematic diagram of the structure of a device according to one embodiment;

[0041] Figure 4 A schematic diagram of the structure of an electronic device according to one embodiment.

[0042] Figure 5 The test results of this invention are compared with those of the existing six-step commutation method.

[0043] Figure 1 In the middle, 1. Brushless DC motor; 2. Inverter;

[0044] Figure 3 In the middle section, 3. Torque ripple suppression device; 31. Adaptive harmonic notch filter; 32. CDSC filter; 33. Park converter unit; 34. Comparator; 35. PI controller; 36. Reference current compensation module; 37. FOC current loop;

[0045] Figure 4 In the Chinese dictionary, 4. electronic devices; 41. processors; 42. memory; 43. input devices; and 44. output devices. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0047] The following terms are used in this specification:

[0048] 1. An Adaptive Harmonic Notch Filter (AHNF) is functionally divided into two parts: a notch filter and an IIR filter. The notch filter includes:

[0049] The harmonic frequency detection function analyzes the current signal in real time based on the gradient descent algorithm to identify the dominant harmonic frequency.

[0050] The frequency adaptive update function dynamically updates the center frequency of the notch filter according to the objective function.

[0051] IIR filters include:

[0052] The IIR filtering function uses a second-order IIR structure to perform real-time filtering and suppress target harmonics that are the same as the center frequency of the notch filter.

[0053] An adaptive harmonic notch filter is also known as an adaptive notch filter.

[0054] 2. CDSC filter: Implements cascaded delay signal cancellation (CDSC) function. It filters out fixed harmonics in current signals by superimposing or subtracting signals through N-stage series delay units.

[0055] 3. Dominant harmonics refer to the harmonics with the largest amplitude and the greatest harm. Generally, the dominant harmonic component of BLDC is the 6th harmonic, but it may also be other harmonics. At high speeds, the dominant harmonic can sometimes exceed the fundamental frequency, resulting in large torque pulsations.

[0056] 4. The target harmonic is the harmonic with the largest amplitude detected in real time by the adaptive notch filter, which is also the dominant harmonic. The notch filter locks the harmonic by dynamically adjusting the center frequency and suppresses it through the IIR filter. The target harmonic is also a harmonic with the same frequency as the center frequency of the notch filter.

[0057] In this embodiment, a high-speed brushless DC motor (BLDC) with a rated voltage of 48V, a rated power of 1.2kW, a pole pair number P of 3, and a rated speed n of 10000rpm is selected.

[0058] Assuming the BLDC converter uses a common star connection without a neutral wire, the third harmonic current must flow through the neutral wire loop. Therefore, the third harmonic current will cancel out between the phase currents, resulting in almost no harmonic current. Besides the fundamental frequency, the 6th and 12th harmonics have the largest amplitudes. In this embodiment, the real-time motor speed ω = 10000 × 2π / 60 = 1047.2 rad / s. The target harmonic frequency f is calculated. n= n·P·ω / 2π, therefore the frequencies of the fundamental, 6th, and 12th harmonics are calculated to be 0.5kHz, 3kHz, and 6kHz, respectively.

[0059] like Figure 2 As shown, the method of the embodiment includes the following steps:

[0060] Step 1: Adaptive Harmonic Suppression Processing

[0061] Step 1.1: Detect the harmonic components of the current signal and calculate the center frequency of the adaptive harmonic notch filter.

[0062] Adaptive harmonic notch filters are a type of real-time suppression technology that combines traditional narrowband notch filters with online parameter self-tuning. According to the literature "Sensorless control of permanent magnet synchronous motor based on extended master-slave adaptive notch filter and dynamic frequency tracking [J]", Ge Yang, Song Weizhang, Yang Yang, Journal of Electrical Engineering, 2023, 38(14):3824-3835, the working principle of adaptive harmonic notch filters is as follows: detect each higher harmonic in the current signal and calculate all harmonic parameters, and then generate a digital filter according to the target harmonic frequency, thereby filtering out or attenuating the target harmonic components and obtaining a more stable fundamental current.

[0063] The three-phase current signal of the BLDC is acquired in real time by a current sensor, and the three-phase current signal I... a I b I c An adaptive harmonic notch filter is input, the center frequency of which is calculated based on the gradient descent method. According to the literature "Adaptive Normal State-Space Notch Digital Filters Using Gradient-Descent Method" (Hinamoto Y., Doi A., Nishimura S, Circuits, Systems and Signal Processing, vol.42, no.7, pp.3983-4001, 2023), the objective function of the gradient descent algorithm is the mean square error of the harmonic components. The objective function of the gradient descent algorithm for the adaptive harmonic notch filter is:

[0064]

[0065] In equation (1), J is the objective function of mean square error, i h For harmonic current components, i h =I h sin(hωt+φ h), where I h It is the harmonic amplitude, ω is the fundamental angular frequency, and φ is the harmonic amplitude. h It is the phase angle, and h is the harmonic order.

[0066] Differentiate the objective function Combined with a learning rate μ = 0.03, the formula for updating the center frequency of the notch filter is:

[0067]

[0068] μ is the learning rate, and 0.001 ≤ μ ≤ 0.1;

[0069] In equation (2), ω h (k) is the current notch filter center angular frequency, ω h (k-1) is the center angular frequency of the notch filter at the previous moment, and k is the discrete time step.

[0070] The gradient descent algorithm continuously optimizes and updates the frequency to ensure that the center frequency of the notch filter matches the frequency of the current harmonic components, adjusting the center frequency of the notch filter so that it can dynamically track the target harmonic frequency.

[0071] An adaptive notch filter has only one center frequency ω. h (k) changes as the motor operates. The adaptive notch filter tracks the target harmonic frequency and can change adaptively. The CDSC filter's center frequency in the following text changes synchronously with the motor's fundamental frequency, and the center frequency is adjusted by a delay T. d Because of the changes, the CDSC filter operates very quickly and saves a lot of resources. Therefore, an adaptive notch filter and a CDSC filter are used together for filtering.

[0072] Step 1.2: Filtering out target harmonics involves updating the center frequency and performing a filter.

[0073] The filter uses a second-order IIR structure, and its difference equation is:

[0074]

[0075] In the formula, x(k) is the original phase current obtained from the current sampling. This is the latest frequency estimate obtained after h iterations, where r is the pole radius, which determines the notch bandwidth, and y(k) is the filtered output. y(k) is used as the new i... h The new center frequency is recalculated by putting it into equation (2) and then the filtering is performed repeatedly.

[0076] Step 1.3: The processed current signal is transmitted to the CDSC filter for superposition or subtraction to filter out higher harmonics.

[0077] The CDSC filter uses N-stage cascaded delay units to perform superposition or subtraction operations on the signals, filtering out the 6k fixed harmonics (k = 1, 2, ..., N) in the current signal to obtain the final fundamental current signal I. a1 I b1 I c1 .

[0078] The CDSC filter first sends the current from the adaptive notch filter to the N-stage digital delay unit. Because the CDSC filter is designed to filter out the 6th and 12th harmonics, its delay time is set to T / 6k of the electrical cycle. Then, the current (i.e., the current from the adaptive notch filter) is added to or subtracted from the delayed current (the target harmonics are superimposed if their phase difference is 180° after the calculation, or subtracted if their phase difference is 0°). This cancels out the 6th and 12th harmonics, while the fundamental frequency is almost unaffected due to its only 60° phase difference. In this embodiment, the delay is set to T / 6k, and the phase difference between the delayed 6th and 12th harmonics and the original harmonics is 0 degrees; therefore, the 6th and 12th harmonics are subtracted and canceled out.

[0079] In the torque control of BLDC, the main harmonics are the 6th and 12th harmonics, and the amplitude of the harmonics may even be greater than the fundamental frequency amplitude. Therefore, the CDSC filter has N=2 stages, with the first stage filtering out the 6th harmonic and the second stage filtering out the 12th harmonic. According to the literature "AFrequency-Adaptive Delay Signal Cancelation Based Filter to Reduce PositionEstimation Error for Sensorless IPMSM Drives" (Wu Z., Cheng C., Hua W., Wang Y., Zhang H., Wang W, IEEE Transactions on Power Electronics, vol.38, no.2, pp.1662–1671, 2023. DOI:10.1109 / TPEL.2022.3214270), the delay time of each stage filter is controlled by the electrical period T and the harmonic order k. d The calculation formula is:

[0080]

[0081] With f = 0.5kHz and T = 2ms, the first-stage CDSC filter has a delay time of 333.3µs to filter out the 6th harmonic, and the second-stage CDSC filter has a delay time of 166.7µs to filter out the 12th harmonic, ultimately outputting a pure fundamental current signal I. a1 I b1 I c1 .

[0082] Step 2: Calculation of phase compensation angle based on FOC (Field Oriented Control) algorithm

[0083] According to the literature "Sensorless Field Oriented Control of Synchronous Machines for Low and High Speeds with Space Vector Modulation-Based Direct Flux Control Measurement Sequence[J]" (“Sensorless Field Oriented Control of Synchronous Machines for Low and High Speeds with Space Vector Modulation-Based Direct Flux Control Measurement Sequence”), Iturra RG, Thiemann P, Electronics, 2023, 12(6):1382.DOI:10.3390 / electronics12061382, the field orientation control projects the three-phase stator currents onto a dq reference frame that rotates synchronously with the rotor flux linkage after Park transformation, thereby completely decoupling the flux linkage (d-axis) and torque (q-axis) current of the AC motor. The controller only needs to adjust i, just like a DC motor. d Size to maintain magnetic flux; adjust i q The magnitude is used to determine the electromagnetic torque.

[0084] For the fundamental current signal I a1 I b1 I c1 Perform a Park transform to convert the fundamental current signal from the stationary reference frame to the synchronous reference frame, and obtain the d-axis current I. d and q-axis current I q The rotation angle θ of the Park transform is measured by three Hall sensors H. A H B H C Real-time acquisition; the PI controller generates a phase delay angle based on the d-axis current error, providing the necessary phase adjustment for subsequent dynamic phase compensation.

[0085] The d-axis current I obtained in the synchronous reference frame d With the target reference current I dref(The target reference current is the desired current setting value maintained on the d-axis, which changes with different requirements. This invention sets it to 0 because the d-axis is used to maintain the magnetic flux, and the q-axis determines the electromagnetic torque.) A comparison is made, and the current error I on the d-axis is calculated. e =I dref -I d .

[0086] The magnitude of the q-axis current represents the magnitude of the torque. To maximize the torque, this embodiment sets a target reference current I for the d-axis. dref It is 0.

[0087] According to the literature "A Frequency-Adaptive Delay Signal Cancelation Based Filter to Reduce Position Estimation Error for Sensorless IPMSM Drives" (“A Method for Suppressing Position Error of Sensorless IPMSM Rotor Based on Frequency-Adaptive Delay Signal Cancelation Filter [J]”), Z.Wu, C.Cheng, W.Hua, Y.Wang, H.Zhang and W.Wang, IEEE Transactions on Power Electronics, vol.38, no.2, pp.1662-1671, Feb.2023, DOI:10.1109 / TPEL.2022.3214270: Based on I… e As input, a phase delay angle Δθ is generated by a PI controller. The formula for calculating this phase delay angle is:

[0088] Δθ=K p ·I e +K i ∫I e dt (4)

[0089] In equation (4), K p K is the proportionality coefficient. i is the integral coefficient.

[0090] In this embodiment, the scaling factor K p =0.8, integral coefficient K i When the value is 50, both the control effect and the system response time meet the requirements.

[0091] Step 3: Dynamic phase compensation based on FOC algorithm

[0092] The phase delay angle Δθ calculated in step 2 is passed through the reference current compensation module to generate compensation amounts for the d-axis and q-axis current reference values. According to the literature "An Angle-Compensating, Complex-Coefficient PI Controller Used for Decoupling Control of a Permanent-Magnet Synchronous Motor" (“An Angle-Compensating, Complex-Coefficient PI Controller Used for Decoupling Control of a Permanent-Magnet Synchronous Motor”), Guo J, Fan T, Li Q, Wen X, Symmetry, 14(1), 101, 2022. DOI 10.3390 / sym14010101, the compensation amounts for the d-axis and q-axis reference currents are:

[0093] ΔI d =-K d ·Δθ、ΔI q =K q ·Δθ (5)

[0094] In equation (5), ΔI d The magnitude of the d-axis reference current compensation is ΔI. q K represents the magnitude of the q-axis reference current compensation. d K q This refers to the compensation gain, which is not fixed. Most often, these two parameters are adjusted manually, typically K. d K is between [0.5, 1.5]. q Between [0.1, 0.5]. Or K d K q Calculated using theoretical formulas, L q and L d For motor inductance parameters, I rated For the rated current, θ max The maximum permissible phase error is given by ω, which is the electric angular velocity. However, this value will be adjusted after calculation, and the result calculated by the formula is generally used as the initial value.

[0095] Figure 2 In the middle, Hall sensor H A H B H C The measured rotation angle θ is used for Park transform, and ω is used to calculate the compensation gain K. q .

[0096] The compensated current reference value The input FOC current loop, after performing the Park inverse transformation within the current loop, calculates the three-phase voltages Va, Vb, and Vc. The PWM generator adjusts the duty cycle based on the three-phase voltages to generate PWM drive signals, making the real-time phase delay Δθ of the phase current relative to the back EMF approach zero, thus achieving phase synchronization between the phase current and the back EMF, thereby suppressing torque ripple in the high-speed brushless DC motor. The q-axis reference current I... qref The value is: the set rotational speed is the reference rotational speed n. ref Then, the actual rotational speed n is collected, and the speed error is n. ref -n; then input the speed error into the speed PI controller, and generate the required q-axis reference current according to the formula of the PI controller (in the same form as formula (4)). The proportional coefficient and integral coefficient are determined by empirical method.

[0097] This invention is entirely implemented in software, requiring no additional hardware. The algorithm is written into the existing BLDC controller using MATLAB and then executed there. The current sensor (detecting three-phase current) and Hall effect sensor (detecting angle) are hardware components originally required by the motor.

[0098] like Figure 3 As shown, the high-speed brushless DC motor torque ripple suppression device 3 of the present invention includes the following parts:

[0099] The adaptive harmonic notch filter 31 is used to receive three-phase current signals, identify the dominant harmonic frequencies, and dynamically update the notch filter center frequency according to the objective function; it employs a second-order IIR structure to perform real-time filtering, suppressing harmonics and harmonics.

[0100] Target harmonics with the same center frequency as the notch filter;

[0101] CDSC filter 32 receives current data processed by adaptive harmonic notch filter 31, performs superposition or subtraction operations on the current through N-stage series delay units, filters out the 6k fixed harmonics in the current signal, and obtains the final fundamental current signal I. a1 I b1 I c1 ;

[0102] Park transform unit 33 is used to convert the fundamental current signal from the stationary reference frame to the synchronous reference frame to obtain the d-axis current I. d and q-axis current I q ;

[0103] Comparator 34 is used to compare the d-axis current I in a synchronous reference frame. d With the target reference current I dref By comparison, the current error I along the d-axis is calculated. e =Idref -I d ;

[0104] PI controller 35, with I e The input is used to generate the phase delay angle Δθ;

[0105] Reference current compensation module 36 is used to generate compensation amounts for the d-axis and q-axis current reference values ​​from the phase delay angle Δθ, thus obtaining the compensated current reference value I. d * and I q * ;

[0106] FOC current loop 37 is used to transfer the compensated current reference value I d * and I q * Calculate the dq voltage V d V q The dq voltage is converted into three-phase voltages Va, Vb, and Vc by performing an inverse Park transformation. The PWM generator adjusts the duty cycle according to the three-phase voltage to generate PWM drive signals, so that the real-time phase delay Δθ of the phase current relative to the back electromotive force approaches 0.

[0107] According to the literature “Torque Ripple Suppression of Brushless DC Motor Drive System Based on Improved Harmonic Injection Active Disturbance Rejection Control[J]”, HE Jinglun, YAN Changxiang, WANG Xiaodong, Sensors, 2022, 22(3):1069.DOI:10.3390 / s22031069: The FOC current loop is a PI controller used to adjust the error between the d-axis current and the q-axis current in the dq coordinate system to generate the dq-axis voltage V. d V q Then, the dq voltage is subjected to inverse park transformation to convert it into three-phase voltages Va, Vb, and Vc; the PWM generator generates PWM drive signals by adjusting the duty cycle of the three-phase voltages Va, Vb, and Vc.

[0108] The PWM drive signal controls the pulse signal that turns the power switching devices in the inverter on and off, thereby adjusting the amplitude and phase of the BLDC phase current and realizing motor control.

[0109] The high-speed brushless DC motor torque ripple suppression device provided by this invention can execute the high-speed brushless DC motor torque ripple suppression method provided in the embodiments herein, and possesses the corresponding functional modules and beneficial effects of this invention. Contents not described in detail in the device embodiments of this invention can be referred to the descriptions in the method embodiments.

[0110] like Figure 4 The diagram shown is a structural schematic of an electronic device provided in an embodiment of the present invention, used to exemplarily illustrate the electronic device for implementing the high-speed brushless DC motor torque ripple suppression method provided in this embodiment. The electronic device 4 can be a controller or a portable mobile terminal, such as a smartphone, vehicle terminal, tablet computer, MP3 player, MP4 player, laptop computer, or desktop computer. The electronic device 4 may also be referred to as a control center, user equipment, portable terminal, laptop terminal, desktop terminal, or other names.

[0111] Typically, electronic device 4 includes one or more processors 41 and memory 42.

[0112] The processor 41 may be a central processing unit (CPU) or other form of processing unit with data processing and / or instruction execution capabilities, and may control other components in the electronic device 4 to perform desired functions.

[0113] The memory 42 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and / or cache memory. Non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium. The processor 41 can execute the program instructions to implement the high-speed brushless DC motor torque ripple suppression method provided in this embodiment of the invention, and can also implement other desired functions. Various contents such as input signals and signal components may also be stored in the computer-readable storage medium.

[0114] The high-speed brushless DC motor torque ripple suppression method provided in this embodiment of the invention may include: dynamically adjusting the center frequency through an adaptive harmonic notch filter to suppress the dominant harmonic component in real time, and combining this with cascaded delay signal elimination; filtering out the 6k fixed harmonics using a CDSC filter to obtain the fundamental current signal; performing Park transformation on the fundamental current based on the FOC algorithm; generating a phase delay angle based on the d-axis current error using a PI controller; and then dynamically compensating the current reference value through inverse Park transformation to ensure phase synchronization between the phase current and the back electromotive force.

[0115] Electronic device 4 may also include an input device 43 and an output device 44, which are interconnected via a bus system and / or other forms of connection mechanism.

[0116] In addition, the input device 43 may include, for example, a three-phase current sensing sensor, a Hall sensor, a keyboard, a mouse, etc.

[0117] The output device 44 can output information to the outside, including phase current phase information, etc.

[0118] The output device 44 may include, for example, a display, a speaker, a printer, and a communication network and its connected downstream devices (such as PWM generators and inverters), etc.

[0119] Of course, for the sake of simplicity, Figure 4 Only the components of the electronic device 4 relevant to the present invention are shown, omitting components such as buses, input / output interfaces, etc. In addition, the electronic device 4 may include any other suitable components depending on the specific application.

[0120] This invention also provides a computer program product, which includes a computer program or computer program instructions. When executed by a computing device, the computer program or computer program instructions cause the computing device to implement the high-speed brushless DC motor torque ripple suppression method provided in this invention. The computer program product can be written with program code for performing the operations of this invention using any combination of one or more programming languages.

[0121] Furthermore, embodiments of the present invention also provide a computer-readable storage medium storing computer program instructions thereon, which, when executed by a computing device, cause the computing device to implement the high-speed brushless DC motor torque ripple suppression method provided in embodiments of the present invention.

[0122] The high-speed brushless DC motor torque ripple suppression method provided in this invention embodiment may include: dynamically adjusting the center frequency through an adaptive harmonic notch filter to suppress the dominant harmonic component in real time, and combining this with cascaded delay signal elimination; filtering out the 6kth fixed harmonic using a CDSC filter to obtain the fundamental current signal; performing Park transform on the fundamental current based on the FOC algorithm; generating a phase delay angle based on the d-axis current error using a PI controller; and then dynamically compensating the current reference value through inverse Park transform to ensure phase synchronization between the phase current and the back electromotive force.

[0123] Computer-readable storage media can be readable signal media or readable storage media. Readable storage media can be, for example, but not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any combination thereof. Readable storage media include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0124] Comparison of test results between the present invention and the existing six-step commutation method

[0125] Simulation experiments were conducted on the Matlab / Simulink platform to compare the present invention with the existing six-step commutation method. The load torque was set to 2 Nm, the rotational speed to 10000 r / min, and the torque ripple T was set to... rip The calculation method is as follows:

[0126]

[0127] In equation (6), T max T represents the maximum torque value measured. min T is the minimum torque value measured. ave This represents the average torque value measured.

[0128] like Figure 5 The output torque ripple state shown: T of the six-step commutation method max T min T ave And T rip The specific values ​​are 2.81 Nm, 2.49 Nm, 2.57 Nm, and 12.5% ​​respectively; the T of this invention max T min T ave And T rip The values ​​are 2.59 Nm, 2.43 Nm, 2.51 Nm, and 6.37%, respectively.

[0129] This invention enables the suppression of torque ripple in BLDC circuits, thereby improving the performance of BLDC operation.

Claims

1. A method for suppressing torque ripple in a high-speed brushless DC motor, characterized in that, Includes the following steps: Step 1: Adaptive Harmonic Suppression Processing Acquiring the three-phase current signal I of a brushless DC motor a I b I c The adaptive harmonic notch filter and CDSC filter are used to suppress the dominant harmonic components in the three-phase current in real time. The adaptive harmonic notch filter dynamically adjusts the center frequency of the notch filter based on the gradient descent algorithm to track and filter out the target harmonic components. The processed signal is input into the CDSC filter, and through the superposition and subtraction of N-stage series delay units, the 6m fixed harmonics are filtered out, m=1,2,…,N, to obtain the fundamental current signal I. a1 I b1 I c1 ; Step 2: Calculation of phase compensation angle based on FOC algorithm The fundamental current signal I after filtering in step 1 a1 I b1 I c1 Perform a Park transform to convert the fundamental current signal from the stationary reference frame to the synchronous reference frame, and obtain the d-axis current I. d and q-axis current I q ; Reference current I along the d-axis dref Obtain the d-axis current error I e =I dref -I d , with I e As input, the phase delay angle is generated by the PI controller. The formula for calculating the phase delay angle is: In the formula, This is the proportionality coefficient. The integral coefficient; Step 3: Dynamic phase compensation based on FOC algorithm Phase delay angle The compensation amount for the d-axis and q-axis current reference values ​​is generated through the reference current compensation module. , for: 、 In the formula, ΔI d The magnitude of the d-axis reference current compensation is ΔI. q K represents the magnitude of the q-axis reference current compensation. d K q It is a compensation gain; K d K is between [0.5, 1.5]. q K is between [0.1, 0.5]. d K q First, calculate the initial values ​​using theoretical formulas. , and These are the motor inductance parameters. Rated current, For the maximum permissible phase error, The electric angular velocity is calculated initially and then adjusted later. The compensated current reference value , The input FOC current loop is processed, and after performing the Park inverse transformation within the current loop, the three-phase voltages Va, Vb, and Vc are calculated. The PWM generator adjusts the duty cycle based on the three-phase voltages to generate PWM drive signals, causing a real-time phase delay of the phase current relative to the back electromotive force. Approaching 0.

2. The method for suppressing torque ripple in a high-speed brushless DC motor according to claim 1, characterized in that: in In step 1, the objective function of the gradient descent algorithm is: In the formula, J is the mean square error function of the harmonic components. These are harmonic current components; The formula for updating the center frequency of the notch filter is: For the learning rate, and ; In the formula, ω h (k) represents the current notch filter center angular frequency, ω h (k-1) is the center angular frequency of the notch filter at the previous moment, and k is the discrete time point.

3. The method for suppressing torque ripple in a high-speed brushless DC motor according to claim 2, characterized in that: in In step 1, filtering out the target harmonics involves updating the center frequency once and performing a filter once: The filter uses a second-order IIR structure, and its difference equation is: In the formula, This is the filtered output. This is the original phase current obtained from the current sampling. It is the latest frequency estimate obtained after h iterations. It is the radius of the pole.

4. The method for suppressing torque ripple in a high-speed brushless DC motor according to claim 3, characterized in that: in In step 1, the CDSC filter has N=2 stages, with the first stage filtering out the 6th harmonic and the second stage filtering out the 12th harmonic; the delay time for each stage is... T is the electrical period, and m is the series number corresponding to the harmonic order.

5. The high-speed brushless DC motor torque ripple suppression device according to claim 1, characterized in that, Includes the following parts: An adaptive harmonic notch filter is used to receive three-phase current signals, identify the dominant harmonic frequency, and dynamically update the notch filter center frequency according to the objective function; a second-order IIR structure is used to perform real-time filtering to suppress the target harmonic that is consistent with the notch filter center frequency; The CDSC filter is used to receive current data processed by the adaptive harmonic notch filter. It performs superposition or subtraction operations on the current through N-stage series delay units to filter out the 6m fixed harmonics in the current signal, obtaining the final fundamental current signal I. a1 I b1 I c1 ; The Park transform unit is used to convert the fundamental current signal from the stationary reference frame to the synchronous reference frame to obtain the d-axis current I. d and q-axis current I q ; The comparator is used to convert the d-axis current I in a synchronous reference frame. d With the target reference current I dref By comparison, the current error I along the d-axis is calculated. e =I dref -I d ; PI controller, using I e The input is used to generate the phase delay angle. ; The reference current compensation module is used to adjust the phase delay angle. The compensation amount is used to generate the d-axis and q-axis current reference values, resulting in the compensated current reference value I. d * and I q * ; The FOC current loop is used to convert the compensated current reference value I... d * and I q * Calculate the dq voltage V d V q The dq voltage undergoes an inverse Park transformation to convert it into three-phase voltages Va, Vb, and Vc. The PWM generator adjusts the duty cycle based on the three-phase voltages to generate PWM drive signals, causing a real-time phase delay of the phase current relative to the back electromotive force. Approaching 0.

6. An electronic device comprising a memory and a processor, characterized in that: The memory stores a computer program, which, when executed by the processor, causes the electronic device to implement the high-speed brushless DC motor torque ripple suppression method according to any one of claims 1-4.

7. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by the computing device, the computing device implements the high-speed brushless DC motor torque ripple suppression method according to any one of claims 1-4.

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