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

Abstract

The invention discloses a high-speed brushless direct current motor torque ripple suppression method, device and equipment and a storage medium, and belongs to the technical field of motor control. The method comprises three steps of adaptive harmonic suppression processing, phase compensation angle calculation and dynamic phase compensation. According to the invention, the center frequency is dynamically adjusted through the adaptive harmonic wave notch filter, the dominant harmonic component is inhibited in real time, and in combination with cascade delay signal elimination, 6k fixed subharmonics are filtered through the CDSC filter, so that a fundamental wave current signal is obtained; park transformation is carried out on the fundamental wave current based on an FOC algorithm, a PI controller is utilized to generate a phase delay angle according to a d-axis current error, and then a reference current compensation module dynamically compensates a current reference value to ensure phase synchronization of phase current and back electromotive force. Compared with the prior art, additional hardware equipment is not needed, and the torque ripple of the BLDC is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor control, and in particular relates to a method for suppressing torque pulsation of a high-speed brushless DC motor based on adaptive harmonic suppression and dynamic phase compensation, as well as a device, equipment and storage medium thereof. Background Art

[0002] Brushless DC motors (BLDC) are widely used in many high-speed applications such as compressors, blowers, and drills 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. The existing six-step conduction control method usually requires six discrete commutation points:

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

[0004] AC power on: S1, S6 open

[0005] bc powered on: S3, S6 open

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

[0007] ca powered on: S5, S2 open

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

[0009] The inverter 2 is triggered to commutate every 60 electrical degrees, so that the DC power supply is supplied to the brushless DC motor 1. Three Hall sensors H are also installed on the stator of the brushless DC motor 1. A , H B , H C , used to detect the spatial angle of the brushless DC motor's rotor along its circumference. However, phase delay error often occurs during the commutation process, causing misalignment between the phase current and the back EMF, resulting in significant torque ripple in the BLDC. At high speeds, the primary cause of phase delay error is the hysteresis effect of the motor coil inductance, which causes the phase current to lag behind the back EMF. Furthermore, at high speeds, the phase current is prone to generating high-order harmonics, making calculation of the phase delay error difficult.

[0010] Traditional methods use commutation based on the zero point of back EMF. Because the phase current lags behind the back EMF, an advance angle is required to offset the current delay caused by the inductance, synchronizing the phase current input to the motor with the back EMF and achieving a smoother motor output torque. Existing methods for eliminating phase delay are mainly divided into two categories: open-loop compensation and closed-loop compensation. Open-loop compensation offsets phase delay by advancing the commutation angle or using model predictions. However, 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. This results in a long dynamic response time and makes it difficult to adapt to high-speed transient changes. Closed-loop compensation primarily relies on a phase-locked loop (PLL) to track the back EMF phase. However, harmonic interference can easily cause the PLL to lose lock under high-speed operating conditions. Furthermore, the phase difference allowed between the natural oscillation wave and the input signal is limited in the PLL. Furthermore, a high-precision encoder or additional sensor is required, significantly increasing hardware costs. Summary of the Invention

[0011] In response to 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 pulsation of a high-speed brushless DC motor. It suppresses broadband harmonic interference in real time through two-stage harmonic filtering and dynamically corrects the phase error in combination with d-axis current feedback, thereby solving the phase delay problem of phase current and back electromotive force caused by inductive lag effect and harmonic pollution under high-speed working conditions, and reducing the torque pulsation of the motor.

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

[0013] Step 1: Adaptive harmonic suppression processing

[0014] Collect the three-phase current signal I of the brushless DC motor a , I b , I c , input the adaptive harmonic notch filter and the CDSC filter 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 the 6kth fixed harmonic is filtered out through the superposition and subtraction operations of N-stage delay units in series, where 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 Park transformation 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 ;

[0017] Through the d-axis reference current I dref Get the d-axis current error I e =I dref -I d , with I e As input, the phase delay angle Δθ is generated by the PI controller. The calculation formula of the phase delay angle is:

[0018] Δθ=K p I e +K i ∫I e dt

[0019] Where K p is the proportionality coefficient, K i is the integration coefficient;

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

[0021] The phase delay angle Δθ is used to generate the compensation value ΔI of the d-axis and q-axis current reference values ​​through the reference current compensation module. d , ΔI q for:

[0022] ΔI d =-K d Δθ, ΔI q =K q ·Δθ

[0023] Where, ΔI d is the d-axis reference current compensation value, ΔI q is the q-axis reference current compensation value, K d , K q is the compensation gain;

[0024] The compensated current reference value The FOC current loop is input, and after the Park inverse transform is completed within 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 voltages to generate a PWM drive signal, so that the real-time phase delay Δθ of the phase current relative to the back electromotive force approaches 0, achieving phase synchronization between the phase current and the back electromotive force.

[0025] In a second aspect, an embodiment of the present invention provides a high-speed brushless DC motor torque ripple suppression device, comprising the following parts:

[0026] 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 target function; it uses a second-order IIR structure to perform real-time filtering, suppressing and trapping

[0027] Target harmonics that are consistent with the filter center frequency;

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

[0029] The Park transformation 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 comparison operator is used to convert the d-axis current I d With the target reference current I dref Compare and calculate the d-axis current error I e =I dref -I d ;

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

[0032] The reference current compensation module is used to generate the compensation amount of the d-axis and q-axis current reference values ​​from the phase delay angle Δθ to obtain 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 inversely park transformed and converted into three-phase voltages Va, Vb, and Vc; the PWM generator generates a PWM drive signal according to the duty cycle of the three-phase voltage, so that the real-time phase delay Δθ of the phase current relative to the back electromotive force approaches 0.

[0034] In a third aspect, an embodiment of the present invention provides an electronic device comprising a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the electronic device implements any high-speed brushless DC motor torque pulsation suppression method provided in the embodiments of this document.

[0035] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a computing device, the computing device implements any of the high-speed brushless DC motor torque pulsation suppression methods provided in the embodiments of this document.

[0036] The technical effect of the present invention is to achieve the suppression of BLDC torque pulsation and improve the performance of BLDC operation without adding additional hardware equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings of the present invention are as follows:

[0038] Figure 1 This is the circuit structure diagram of the high-speed brushless DC motor inverter;

[0039] Figure 2 A flowchart of a method according to an embodiment;

[0040] Figure 3 A schematic structural diagram of a device according to an embodiment;

[0041] Figure 4 A schematic structural diagram of an electronic device according to an embodiment

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

[0043] Figure 1 Among them, 1. Brushless DC motor; 2. Inverter;

[0044] Figure 3 3. Torque ripple suppression device; 31. Adaptive harmonic notch filter; 32. CDSC filter; 33. Park conversion unit; 34. Comparison operator; 35. PI controller; 36. Reference current compensation module; 37. FOC current loop;

[0045] Figure 4 Among them, 4, electronic device; 41, processor; 42, memory; 43, input device; 44, output device. DETAILED DESCRIPTION

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

[0047] Terms used in this manual:

[0048] 1. Adaptive Harmonic Notch Filter (AHNF) is divided into two parts according to its function: notch filter and IIR filter. The notch filter includes:

[0049] Harmonic frequency detection function, based on the gradient descent algorithm to analyze the current signal in real time and identify the dominant harmonic frequency;

[0050] Frequency adaptive update function, dynamically updates the center frequency of the notch filter according to the target 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 coincide with the center frequency of the notch filter.

[0053] Adaptive harmonic notch filter is also called adaptive notch filter.

[0054] 2. CDSC filter, implements the cascade delay signal cancellation (CDSC) function, and performs superposition or subtraction operations on the signal through N stages of delay units in series to filter out fixed subharmonics in the current signal.

[0055] 3. Dominant harmonics are those with the largest amplitude and the greatest potential for damage. Generally, the dominant harmonic component of a BLDC is the sixth harmonic, but other harmonics may also be present. At high speeds, the dominant harmonic can sometimes exceed the fundamental harmonic, causing significant torque ripple.

[0056] 4. The target harmonic is the harmonic with the largest amplitude detected in real time by the adaptive notch filter, that is, 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 the harmonic with the same frequency as the notch filter center frequency.

[0057] This embodiment uses 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.

[0058] Assuming that the BLDC is connected in a common star configuration and has no neutral line, the tripled frequency current must flow through the neutral line loop, so the tripled frequency will cancel out between the phase currents, and the tripled frequency harmonic current is almost non-existent. In addition to the fundamental wave, the amplitudes of the 6th and 12th harmonics are the largest. In this embodiment, the real-time speed of the motor ω = 10000 × 2π / 60 = 1047.2 rad / s, and the target harmonic frequency f is calculated. n=n·P·ω / 2π, so the frequencies of the fundamental wave, the 6th harmonic, and the 12th harmonic are calculated to be 0.5 kHz, 3 kHz, and 6 kHz, 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 filter is a real-time suppression technology that combines traditional narrowband notch filter with online parameter self-tuning. According to the literature "Sensorless Control of Permanent Magnet Synchronous Motor Based on Expanded Master-Slave Adaptive Notch Filter and Dynamic Frequency Tracking [J]", Ge Yang, Song Weizhang, Yang Yang, Transactions of the Chinese Society of Electrotechnical Engineering, 2023, 38(14): 3824-3835., the working principle of the adaptive harmonic notch filter is: detect each high-order 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 component to obtain a more stable fundamental current.

[0063] The three-phase current signal of BLDC is collected in real time by the current sensor, and the three-phase current signal I a , I b , I c Input an adaptive harmonic notch filter, the center frequency of which is calculated based on the gradient descent method. According to the document "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 formula (1), J is the mean square error objective function, i h is the harmonic current component, i h =I h sin(hωt+φ h), where I h is the harmonic amplitude, ω is the fundamental angular frequency, φ h is the phase angle, and h is the harmonic order.

[0066] Derivative of the objective function Combined with the learning rate μ = 0.03, the center frequency update formula of the notch filter is:

[0067]

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

[0069] In formula (2), ω h (k) is the center angular frequency of the notch filter at the current moment, 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 ensures that the center frequency of the notch filter matches the frequency of the current harmonic component by continuously optimizing the update frequency, and adjusts the center frequency of the notch filter so that it can dynamically track the target harmonic frequency.

[0071] The adaptive notch filter has only one center frequency ω h (k), it will change as the motor runs, and the adaptive notch filter tracks the target harmonic frequency and can change adaptively. The center frequency of the CDSC filter below changes synchronously with the motor fundamental frequency, and the center frequency is adjusted by the delay T d The CDSC filter operates very fast and saves a lot of resources. Therefore, the adaptive notch filter and the CDSC filter are combined for filtering.

[0072] Step 1.2: Filter out the target harmonics and perform a filter by updating the center frequency once.

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

[0074]

[0075] Where x(k) is the original phase current obtained by current sampling, is the latest frequency estimate obtained after h iterations, r is the pole radius, which determines the notch bandwidth, y(k) is the output after filtering, and y(k) is used as the new i h Put it into formula (2), re-iterate and calculate the new center frequency, and then perform filtering repeatedly.

[0076] Step 1.3: Send the processed current signal to the CDSC filter for superposition or subtraction to filter out high-order harmonics.

[0077] The CDSC filter performs superposition or subtraction operations on the signal through N-stage delay units connected in series, filtering out the 6kth 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 an N-stage digital delay unit. Because the CDSC filter is designed to permanently filter out harmonics like the 6th and 12th, its delay duration is set to T / 6k, an electrical cycle. The current (i.e., the current from the adaptive notch filter) is then added or subtracted from the delayed current (if the target harmonics have a phase difference of 180° after the calculation, this is additive cancellation, or a phase difference of 0°, this is subtractive cancellation). This cancels out the 6th and 12th harmonics, while the fundamental wave is barely affected by its phase difference of only 60°. In this embodiment, the delay is set to T / 6k, so the delayed 6th and 12th harmonics have a phase difference of 0° from the original, resulting in subtractive cancellation of both harmonics.

[0079] In BLDC torque control, the main harmonics are the 6th and 12th harmonics, and the amplitude of the harmonics may even be greater than the fundamental amplitude. Therefore, the number of stages of the CDSC filter is N = 2, 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 Position Estimation 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 of the filter is controlled by the electrical cycle T and the harmonic number k. The delay time T d The calculation formula is:

[0080]

[0081] f = 0.5kHz, T = 2ms, the first-stage CDSC filter delay time is 333.3us, which is used to filter out the 6th harmonic, and the second-stage CDSC filter delay time is 166.7us, which is used to filter out the 12th harmonic, and finally outputs a pure fundamental current signal I a1 , I b1 , I c1 .

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

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

[0084] For fundamental current signal I a1 , I b1 , I c1 Perform Park transformation 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 rotation angle θ of the Park transformation 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 required phase adjustment for subsequent dynamic phase compensation.

[0085] In the synchronous reference frame, the d-axis current I d With the target reference current I dref(The target reference current is the current setting value expected to be maintained on the d-axis. It changes with different requirements. The present invention sets it to 0 because the d-axis is used to maintain the magnetic flux and the q-axis determines the electromagnetic torque.) Compare and calculate the d-axis current error I e =I dref -I d .

[0086] The magnitude of the q-axis current represents the magnitude of the torque. In order to maximize the torque, this embodiment sets the target reference current I of the d-axis. dref is 0.

[0087] According to the literature "A Frequency-Adaptive Delay Signal Cancelation Based Filterto Reduce Position Estimation Error for Sensorless IPMSM Drives" ("A Frequency-Adaptive Delay Signal Cancelation Based Filterto Reduce Position Estimation Error for Sensorless IPMSM Drives"[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): e As input, the phase delay angle Δθ is generated by the PI controller. The calculation formula of the phase delay angle is:

[0088] Δθ=K p I e +K i ∫I e dt (4)

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

[0090] In this embodiment, the proportionality coefficient K p =0.8, integral coefficient K i When =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 values ​​for the d-axis and q-axis current reference values. According to the document “An Angle-Compensating, Complex-Coefficient PI Controller Used for Decoupling Control of a Permanent-Magnet Synchronous Motor Based on Angle Compensation and Complex Coefficient PI”, Guo J, Fan T, Li Q, Wen X, Symmetry, 14(1), 101, 2022. DOI 10.3390 / sym14010101, the compensation values ​​for the d-axis and q-axis reference currents are:

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

[0094] In formula (5), ΔI d is the d-axis reference current compensation value, ΔI q is the q-axis reference current compensation value, K d , K q It is the compensation gain. This compensation gain is not fixed. Most of the time, these two parameters are adjusted manually. Generally, K d Between [0.5,1.5], K q Between [0.1,0.5]. Or K d , K q Calculated using the theoretical formula, L q and L d is the motor inductance parameter, I rated is the rated current, θ max is the maximum allowable phase error, and ω is the electrical angular velocity. However, after this is calculated, it will be adjusted later. The result calculated by the general formula is used as the initial value.

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

[0096] The compensated current reference value The FOC current loop is input, and after the Park inverse transform is completed inside the current loop, the three-phase voltages Va, Vb, and Vc are calculated; the PWM generator generates a PWM drive signal based on the duty cycle of the three-phase voltage, so that the real-time phase delay Δθ of the phase current relative to the back electromotive force approaches 0, achieving phase synchronization between the phase current and the back electromotive force, thereby suppressing the torque ripple of the high-speed brushless DC motor. qref The value of is: Set the speed to the reference speed n ref , then collect the actual speed n, the speed error is n ref -n; then, the speed error is input to the speed PI controller, and the required q-axis reference current is generated according to the PI controller formula (the form is consistent with formula (4)), and the proportional coefficient and integral coefficient are determined by the empirical method.

[0097] This method is implemented entirely in software, requiring no additional hardware. The BLDC controller already exists, and the algorithm is written into the controller using MATLAB for execution. The current sensor (for detecting three-phase current) and Hall effect sensor (for detecting angle) are hardware components required for the original 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 the three-phase current signal, identify the dominant harmonic frequency, and dynamically update the notch filter center frequency according to the target function; it uses a second-order IIR structure to perform real-time filtering to suppress the

[0100] Target harmonics with consistent center frequencies of the notch filters;

[0101] The CDSC filter 32 is used to receive the current data processed by the adaptive harmonic notch filter 31, and perform superposition or subtraction operations on the current through N stages of delay units connected in series to filter out the 6kth fixed harmonics in the current signal to obtain the final fundamental current signal I a1 , I b1 , I c1 ;

[0102] The Park transformation unit 33 is used to transform 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] The comparison operator 34 is used to convert the d-axis current I d With the target reference current I dref Compare and calculate the d-axis current error I e =Idref -I d ;

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

[0105] The reference current compensation module 36 is used to generate compensation values ​​of the d-axis and q-axis current reference values ​​by the phase delay angle Δθ to obtain the compensated current reference value I d * and I q * ;

[0106] The FOC current loop 37 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 inversely park transformed and converted into three-phase voltages Va, Vb, and Vc; the PWM generator generates a PWM drive signal according to the duty cycle of the three-phase voltage, so that the real-time phase delay Δθ of the phase current relative to the back electromotive force approaches 0.

[0107] According to the document “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 in the dq coordinate system, and the PI controller is used to adjust the error between the d-axis current and the q-axis current to generate the dq-axis voltage V d ,V q , then the dq voltage is inversely transformed by park and converted into three-phase voltages Va, Vb, and Vc; the PWM generator generates a PWM drive signal by adjusting the duty cycle through the three-phase voltages Va, Vb, and Vc.

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

[0109] The high-speed brushless DC motor torque ripple suppression device provided by the present invention can implement the high-speed brushless DC motor torque ripple suppression method provided in the embodiments herein, and has the corresponding functional modules and beneficial effects required to implement the method. Any details not fully described in the device embodiments of the present invention can be referenced in the description of the method embodiments.

[0110] like Figure 4 FIG4 is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention, which is used to exemplify an electronic device for implementing the method for suppressing torque ripple of a high-speed brushless DC motor provided in an embodiment of the present invention. The electronic device 4 can be a controller or a portable mobile terminal, such as a smartphone, a vehicle-mounted terminal, a tablet computer, an MP3 player, an MP4 player, a laptop computer, or a desktop computer. The electronic device 4 may also be referred to as a control center, user equipment, a portable terminal, a laptop terminal, a desktop terminal, or other similar names.

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

[0112] The processor 41 may be a central processing unit (CPU) or other forms of processing units having data processing capabilities 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), a hard disk, flash memory, etc. One or more computer program instructions may be stored on a computer-readable storage medium, and the processor 41 may execute the program instructions to implement the high-speed brushless DC motor torque pulsation suppression method provided in an embodiment of the present invention, and may also implement other desired functions. Various contents such as input signals, signal components, etc. may also be stored in the computer-readable storage medium.

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

[0115] The electronic device 4 may further include an input device 43 and an output device 44 , and these components are interconnected via a bus system and / or other forms of connection mechanisms.

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

[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, a communication network and subsequent devices connected thereto (such as a PWM generator and an inverter), etc.

[0119] Of course, to simplify, Figure 4 Only components related to the present invention in the electronic device 4 are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, the electronic device 4 may further include any other appropriate components according to specific application conditions.

[0120] An embodiment of the present invention further provides a computer program product comprising 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 method for suppressing torque ripple of a high-speed brushless DC motor provided by an embodiment of the present invention. The computer program product may be written in any combination of one or more programming languages ​​to contain program code for performing the operations of the embodiments of the present invention.

[0121] In addition, an embodiment of the present invention also provides a computer-readable storage medium on which computer program instructions are stored. When the computer program instructions are executed by a computing device, the computing device implements the high-speed brushless DC motor torque pulsation suppression method provided by an embodiment of the present invention.

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

[0123] The computer-readable storage medium may be a readable signal medium or a readable storage medium. The readable storage medium may include, for example, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any combination thereof. The readable storage medium includes: an electrical connection having one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

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

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

[0126]

[0127] In formula (6), T max is the maximum torque value in the measurement, T min is the minimum torque value in the measurement, T ave is the average torque value in the measurement.

[0128] like Figure 5 Output torque fluctuation state shown: T of six-step commutation method max 、T min 、T ave and T rip They are 2.81Nm, 2.49Nm, 2.57Nm, and 12.5% ​​respectively; T max 、T min 、T ave and T rip They are 2.59Nm, 2.43Nm, 2.51Nm and 6.37% respectively.

[0129] The present invention realizes the function of suppressing the torque pulsation of BLDC and improves the performance of BLDC operation.

Claims

1. A method for suppressing torque ripple of a high-speed brushless DC motor, characterized in that: The following steps are involved: Step 1: Adaptive harmonic suppression processing Collect the three-phase current signal I of the brushless DC motor a , I b , I c , input the adaptive harmonic notch filter and the CDSC filter 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 the 6kth fixed harmonic is filtered out through the superposition and subtraction operations of N-stage delay units in series, where k = 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 Park transformation 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 ; Through the d-axis reference current I dref Get the d-axis current error I e =I dref -I d , with I e As input, the phase delay angle Δθ is generated by the PI controller. The calculation formula of the phase delay angle is: Δθ=K p ·I e +K i ∫I e dt Where K p is the proportionality coefficient, K i is the integration coefficient; Step 3: Dynamic phase compensation based on FOC algorithm The phase delay angle Δθ is used to generate the compensation value ΔI of the d-axis and q-axis current reference values ​​through the reference current compensation module. d , ΔI q for: ΔI d =-K d ·Δθ、ΔI q =K q ·Δθ Where, ΔI d is the d-axis reference current compensation value, ΔI q is the q-axis reference current compensation value, K d , K q is the compensation gain; The compensated current reference value The FOC current loop is input, and after completing the Park inverse transform 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 voltages to generate a PWM drive signal so that the real-time phase delay Δθ of the phase current relative to the back electromotive force approaches 0.

2. The method for suppressing torque ripple of a high-speed brushless DC motor according to claim 1, wherein: In step 1, the objective function of the gradient descent algorithm is: Where J is the mean square error function of the harmonic component, i h is the harmonic current component; The center frequency update formula of the notch filter is: μ is the learning rate, and 0.001≤μ≤0.1; Where, ω h (k) is the center angular frequency of the notch filter at the current moment, ω h (k-1) is the center angular frequency of the notch filter at the previous moment, and k is the discrete time step.

3. The method for suppressing torque ripple of a high-speed brushless DC motor according to claim 2, wherein: In step 1, the target harmonics are filtered out by updating the center frequency once: The filtering adopts a second-order IIR structure, and its difference equation is: Where y(k) is the filtered output, x(k) is the original phase current obtained by current sampling, is the latest frequency estimate obtained after h iterations, and r is the pole radius.

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

5. A high-speed brushless DC motor torque ripple suppression device, characterized in that: Includes the following sections: Adaptive harmonic notch filter receives three-phase current signals, identifies dominant harmonic frequencies, and dynamically updates the notch filter center frequency based on the target function. It uses a second-order IIR structure to perform real-time filtering and suppress target harmonics that coincide with the notch filter center frequency. The CDSC filter is used to receive the current data processed by the adaptive harmonic notch filter, and performs superposition or subtraction operations on the current through N-stage series delay units to filter out the 6kth fixed harmonics in the current signal to obtain the final fundamental current signal I a1 , I b1 , I c1 ; The Park transformation 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 comparison operator is used to convert the d-axis current I d With the target reference current I dref Compare and calculate the d-axis current error I e =I dref -I d ; PI controller, with I e is the input, used to generate the phase delay angle Δθ; The reference current compensation module is used to generate the compensation amount of the d-axis and q-axis current reference values ​​from the phase delay angle Δθ to obtain 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 is inversely park transformed into three-phase voltages Va, Vb, and Vc; the PWM generator generates a PWM drive signal according to the three-phase voltage adjustment duty cycle, so that the real-time phase delay Δθ of the phase current relative to the back electromotive force approaches 0.

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

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

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