Motor inverter dead time adaptive adjustment method for suppressing electromagnetic vibration noise

Abstract

The invention discloses a motor inverter dead time adaptive adjustment method for suppressing electromagnetic vibration noise, and relates to the technical field of motor vibration noise control, and the method comprises the steps: constructing an error voltage model based on dead time; according to the current rotating speed of the motor, adopting an error voltage model to obtain current harmonics in the phase current; radial electromagnetic force is obtained according to the current harmonics and correspondingly generated air gap flux density; determining a vibration response amplitude according to the radial electromagnetic force amplitude, and comparing the vibration response amplitude with a preset vibration threshold; and when the vibration response amplitude is greater than the vibration threshold, determining a target dead zone time and a dead zone compensation amount according to different current rotating speeds of the motor so as to adjust the dead zone of the inverter. The dead time and the dead time compensation amount of the inverter are adaptively adjusted according to the operation conditions, and the problems of current harmonics, electromagnetic force fluctuation and increase of electromagnetic vibration amplitude caused by fixed dead time of the inverter under different operation conditions are solved.

Description

Technical Field

[0001] This invention relates to the field of motor vibration and noise control technology, and in particular to an adaptive adjustment method for dead time of motor inverters to suppress electromagnetic vibration and noise. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Permanent magnet synchronous motors (PMSMs) are widely used in new energy vehicles, electric drive axles, robotics, and aerospace electric propulsion due to their high power density, high efficiency, and excellent dynamic performance. As electric drive systems have evolved to higher speeds, higher carrier frequencies, and higher precision control, motor vibration and noise (NVH) issues have become increasingly prominent. Structural vibrations caused by air-gap electromagnetic forces and their harmonics have become one of the main noise sources. Numerous studies have shown that when the frequency of the electromagnetic force couples with the inherent modes of the stator structure, it leads to a significant increase in radial vibration and noise. Therefore, accurately identifying and suppressing electromagnetic excitation sources is crucial for improving the NVH performance of motors.

[0004] In existing research on motor vibration, electromagnetic vibration typically originates from the following types of factors: The inherent electromagnetic force fluctuations caused by the stator and rotor structure include the cogging force caused by the slot effect, the fundamental radial force generated by the permanent magnet, and the mutual coupling of harmonic magnetic fields.

[0005] Electromagnetic force harmonics caused by current harmonics will appear in the current under the power supply of PWM inverter, such as the 5th and 7th harmonics and carrier harmonics. These harmonics interact with the fundamental magnetic field of permanent magnet, generating additional radial electromagnetic force waves in the air gap, thereby causing stator radial vibration.

[0006] Additional harmonics caused by the non-ideal characteristics of power devices include switching delay and on-state voltage drop. Among these, the inverter dead time is a safety interval that must be inserted to prevent the upper and lower switching devices of the bridge arm from conducting simultaneously.

[0007] In traditional technologies, dead time is primarily used to ensure device safety, with side effects including output voltage drop or distortion; asymmetric errors under different current directions; and the generation of current distortion, torque ripple, and even low-frequency harmonics. However, an important phenomenon is generally overlooked: dead time significantly affects low-order current harmonics such as the 5th and 7th orders. These harmonics interact with the magnetic field of the permanent magnet, causing changes in the amplitude of the air gap electromagnetic force, thereby affecting the electromagnetic vibration response of the motor.

[0008] Furthermore, the impact of dead time on electromagnetic vibration is closely related to the motor's operating speed, essentially a frequency coupling phenomenon. At low speeds, the frequency of electromagnetic force harmonics is low, and the coupling effect with the stator's natural modes is weak. Even with a slightly larger dead time, the resulting current harmonics and electromagnetic vibrations remain relatively limited. At medium to high speeds, as the electrical frequency increases, the frequencies of harmonics such as 5fe and 7fe caused by dead time errors rise, and some orders may approach the natural frequency range of the stator structure. At this point, a dead time error of the same magnitude will generate stronger harmonic excitation, causing significant amplification of electromagnetic vibration. At high speeds (≥5000 rpm), the frequency of electromagnetic force harmonics further approaches the structural modes and may even enter the resonance-sensitive region. A slightly larger dead time can produce obvious vibration spikes and may even lead to noise degradation or structural fatigue risks.

[0009] Traditional fixed dead-time settings only consider the safety margin of devices, without taking into account the impact of dead-time error on harmonic frequencies, electromagnetic coupling, and vibration amplification. This fixed-parameter approach may exhibit stability at low speeds, but it cannot avoid the problem of sudden increases in vibration during medium to high-speed operation. Summary of the Invention

[0010] To address the aforementioned problems, this invention proposes an adaptive dead-time adjustment method for motor inverters to suppress electromagnetic vibration noise. This method adaptively adjusts the inverter dead-time and dead-time compensation amount according to the operating conditions, thus solving the problems of increased current harmonics, electromagnetic force fluctuations, and electromagnetic vibration amplitude caused by a fixed inverter dead-time under different operating conditions.

[0011] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides an adaptive adjustment method for the dead time of a motor inverter to suppress electromagnetic vibration noise, comprising: Construct an error voltage model based on dead time; Based on the current speed of the motor, the current harmonics in the phase current are obtained using the error voltage model; The radial electromagnetic force is obtained based on the current harmonics and the corresponding generated air gap magnetic flux density; The vibration response amplitude is determined based on the radial electromagnetic force amplitude, and then compared with the preset vibration threshold. When the vibration response amplitude is greater than the vibration threshold, the target dead time and dead time compensation amount are determined according to the current speed of the motor, so as to adjust the inverter dead time.

[0012] As an alternative implementation method, the error voltage model is: ; in, This is the DC bus voltage. It is the electric angular frequency. The phase angle is determined by the stator resistance and inductance; is the frequency; n is the rotational speed.

[0013] As an alternative implementation method, the phase current is: ; ; ; in, For stator resistance, The stator is the equivalent inductance; a represents phases A, B, and C. , and The amplitudes of the fundamental frequency, the 5th current harmonic, and the 7th current harmonic; , and The load impedance angles for the fundamental frequency, the 5th current harmonic, and the 7th current harmonic; The load impedance; denoted as DC bus voltage, and n as rotational speed.

[0014] As an alternative implementation, the current harmonics include harmonics with a frequency of (6k±1)f1, where k is a positive integer and f1 is the electric frequency of the motor.

[0015] As an alternative implementation method, the radial electromagnetic force is: ; In the formula, B svi0 B svil B svm0 and B svml Z represents the amplitude of the radial air gap magnetic flux density generated by the stator harmonic current; p is the number of stator slots; μ0 is the number of pole pairs of the motor; and μ0 is the vacuum permeability. For mechanical angle; v, , It is the order; This refers to the rotor's mechanical angular velocity; The initial spatial phase angle of the rotor permanent magnet main pole magnetic flux density relative to the stator reference coordinate system; It is the fundamental magnetic flux density of the permanent magnet's main pole.

[0016] As an alternative implementation, at the same speed, a candidate dead time is preset, and among all dead times that meet the vibration constraints, the selection is made according to the speed range in which the current speed of the motor is located: under low-speed conditions, a relatively large dead time is selected; under medium- and high-speed conditions, the dead time that minimizes vibration is selected, and the corresponding dead time compensation is applied.

[0017] Secondly, the present invention provides an adaptive dead-time adjustment system for a motor inverter to suppress electromagnetic vibration noise, comprising: The model building module is configured to build an error voltage model based on dead time; The harmonic calculation module is configured to obtain the current harmonics in the phase current based on the current speed of the motor and using an error voltage model. The electromagnetic force calculation module is configured to obtain the radial electromagnetic force based on the current harmonics and the corresponding generated air gap magnetic flux density; The evaluation module is configured to determine the vibration response amplitude based on the radial electromagnetic force amplitude and compare the vibration response amplitude with a preset vibration threshold. The adjustment module is configured to determine the target dead time and dead time compensation amount based on the current speed of the motor when the vibration response amplitude is greater than the vibration threshold, thereby adjusting the inverter dead time.

[0018] Thirdly, the present invention provides an electronic device including a memory and a processor, and computer instructions stored in the memory and running on the processor, wherein the computer instructions, when executed by the processor, perform the method described in the first aspect.

[0019] Fourthly, the present invention provides a computer-readable storage medium for storing computer instructions, which, when executed by a processor, perform the method described in the first aspect.

[0020] Fifthly, the present invention provides a computer program product, including a computer program that, when executed by a processor, implements the method described in the first aspect.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Effectively reduces the amplitude of current harmonics caused by dead-time error. This invention collects current waveforms and analyzes current harmonic components under multiple operating conditions, and determines the optimal dead-time and compensation amount, so that the inverter adopts appropriate dead-time parameters under different operating conditions. Compared with the traditional fixed dead-time method, it can significantly reduce the amplitude of the 5th and 7th low-order current harmonics caused by dead-time error, thereby improving the current waveform quality.

[0022] (2) Suppressing the amplification effect of dead time on the radial electromagnetic force of the air gap, thereby reducing electromagnetic vibration. Since the coupling between current harmonics and the fundamental magnetic field of the permanent magnet will form an additional radial electromagnetic force, this invention reduces the increase of key electromagnetic force components such as the 0th and 2p orders by limiting the amplitude of the above harmonics, thereby reducing the electromagnetic excitation acting on the stator from the source. Therefore, under medium and high speed conditions, it can effectively suppress the phenomenon of increased peak electromagnetic vibration of the motor caused by the enhancement of harmonic excitation.

[0023] (3) Adapting to vibration characteristics at different speeds to achieve full-condition optimization. Traditional fixed dead zone settings can only optimize a single operating area, and often result in a significant increase in vibration under medium and high speed conditions. This invention establishes a mapping relationship between operating speed and target dead zone time / compensation amount, so that the dead zone parameters are automatically adjusted according to the operating state. This method can take into account low-speed, medium-speed and high-speed operating areas, so that the motor maintains a low level of electromagnetic vibration across the entire speed range.

[0024] (4) It has strong engineering feasibility and can be directly integrated into existing motor controllers. This invention only adds three types of algorithm modules: current harmonic analysis, dead-time parameter mapping, and dead-time dynamic setting. It does not require changes to the inverter hardware structure or the motor body structure, and can be directly embedded into common FOC, DTC and other control systems. Its implementation is simple, requires little hardware modification, and has good engineering applicability and versatility.

[0025] (5) Meets the requirements of high noise and vibration in application scenarios. By dynamically optimizing dead time and compensation, this invention can significantly reduce the noise and vibration levels of the motor in high-precision and high-comfort scenarios (such as new energy vehicles, robots, home appliance compressors, etc.), thereby improving the overall system's operational stability and user experience.

[0026] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0028] Figure 1 This is a flowchart of the adaptive adjustment method for dead time of motor inverter for suppressing electromagnetic vibration noise provided in Embodiment 1 of the present invention; Figure 2 This is the main circuit topology diagram of the voltage source three-phase inverter used in Embodiment 1 of the present invention; Figure 3 This is a diagram illustrating the actual impact of dead time on the inverter output phase voltage, provided in Embodiment 1 of the present invention. Figure 4 This is a three-phase current waveform diagram with a dead time of 0 μs provided in Embodiment 1 of the present invention; Figure 5 The three-phase current waveform diagram with a dead time of 6μs provided in Embodiment 1 of the present invention; Figure 6 The harmonic spectrum diagram of three-phase current under different dead time conditions provided in Embodiment 1 of the present invention; Figure 7 This is a spatiotemporal distribution diagram of the electromagnetic force of a motor under a dead time of 0 μs, provided in Embodiment 1 of the present invention. Figure 8 This is a spatiotemporal distribution diagram of the electromagnetic force of a motor under a dead time of 6μs, provided in Embodiment 1 of the present invention. Figure 9 The vibration spectrum of the motor at a speed of 500 r / min under different dead times is provided in Embodiment 1 of the present invention; Figure 10 The noise spectrum diagram of a 500 r / min rotation speed under different dead times provided in Embodiment 1 of the present invention; Figure 11 The vibration spectrum of the motor at a speed of 1500 r / min under different dead times is provided in Embodiment 1 of the present invention; Figure 12 The noise spectrum diagram of 1500 r / min rotation speed under different dead times provided in Embodiment 1 of the present invention; Figure 13 This is a comparison diagram of vibration spectra before and after harmonic compensation provided in Embodiment 1 of the present invention. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, 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 invention pertains.

[0031] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. Furthermore, it should be understood that the terms “comprising” and “including”, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0032] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0033] Example 1 like Figure 1As shown, this embodiment provides an adaptive adjustment method for the dead time of a motor inverter to suppress electromagnetic vibration noise, including: Construct an error voltage model based on dead time; Based on the current speed of the motor, the current harmonics in the phase current are obtained using the error voltage model; The radial electromagnetic force is obtained based on the current harmonics and the corresponding generated air gap magnetic flux density; The vibration response amplitude is determined based on the radial electromagnetic force amplitude, and then compared with the preset vibration threshold. When the vibration response amplitude is greater than the vibration threshold, the target dead time and dead time compensation amount are determined according to the current speed of the motor, so as to adjust the inverter dead time.

[0034] This embodiment establishes a mathematical model of the effect of inverter dead time on phase voltage, phase current and electromagnetic force of permanent magnet synchronous motor, and explains the mechanism by which changes in dead time lead to enhanced electromagnetic vibration.

[0035] This embodiment is based on an 8-pole, 48-slot permanent magnet synchronous motor, and the main circuit topology of the voltage source three-phase inverter used is as follows: Figure 2 As shown, the inverter consists of three arms, each containing two power switching devices (upper and lower). A fixed dead time is set in the control to avoid shoot-through failures. This circuit structure serves as the basis for the dead-time effect analysis in this embodiment and is consistent with existing motor drive systems.

[0036] This embodiment compares phase current harmonics and electromagnetic vibration noise by setting different inverter dead times.

[0037] Based on the motor's maximum speed, rated speed, and low-speed operating conditions, several typical operating points are selected as the set of operating conditions for dead-time optimization. Under each operating condition, the inverter dead time is set to multiple candidate values. 1. 2. 3……, and ensure stable operation of the motor.

[0038] The dead time set by the inverter to ensure the safety of device commutation will cause the output voltage to have an error related to the current direction, thus forming 6k±1 harmonic components such as the 5th and 7th harmonics in the current.

[0039] After acquiring the three-phase current, the fundamental current amplitude, the 5th current harmonic i5, and the 7th current harmonic i7 are extracted using Fast Fourier Transform (FFT), Discrete Fourier Transform (DFT), or harmonic analysis module. The changing trends of i5 and i7 under different dead times are recorded to reflect the relationship between dead time error and harmonic amplitude.

[0040] like Figure 3 The diagram shown illustrates the actual impact of dead time on the inverter's output phase voltage; as follows: Figures 4-5 The figure shows the three-phase current waveforms under different dead times, namely the three-phase current waveforms with a dead time of 0 μs and 6 μs; as shown. Figure 6 The diagram shows the harmonic spectrum of the three-phase current under different dead times.

[0041] The three-phase voltage source inverter uses SVPWM modulation, and a dead time is set between the bridge arm switches. Within one PWM carrier cycle, the output voltage of each phase of the inverter is determined by the sign of the current reference voltage, the modulation duty cycle, the direction of the phase current, and the dead time.

[0042] Specifically, when the phase current direction is not consistent with the expected conduction direction of the device, the anti-parallel diode will conduct during the dead time, resulting in a low output voltage; conversely, when the current direction is consistent, the output voltage may be high during the dead time.

[0043] To quantify this offset, this embodiment constructs an error voltage model based on the inverter's voltage switching function and dead time. Ignoring switching delay differences, the following is obtained by performing a Fourier expansion on the inverter output voltage: ; in, This is the DC bus voltage. It is the electric angular frequency. The phase angle is determined by the stator resistance and inductance; is the frequency; n is the rotational speed.

[0044] It can be seen that the harmonic components include harmonics with a frequency of (6k±1)f1, where k is a positive integer and f1 is the electric frequency of the motor; the 6k±1 harmonic is a characteristic harmonic component introduced by the dead time. When k=1, it corresponds to the 5th and 7th harmonics, which are the focus of subsequent analysis.

[0045] The above error voltage is applied to the equivalent impedance of the motor. u Its phase current can be further obtained, expressed as: ; ; ; in, For stator resistance, The stator is the equivalent inductance; a represents phases A, B, and C. , and These represent the amplitudes of the fundamental frequency, the 5th, and the 7th current harmonics. , and The load impedance angles for the fundamental, 5th, and 7th current harmonics; This is the load impedance.

[0046] Therefore, with other parameters constant, an increase in dead time leads to an increase in effective error voltage, further increasing the 5th and 7th harmonic currents, and significantly enhancing waveform distortion. Figures 4-6 The changes in the three-phase current waveform and harmonic spectrum are consistent under different dead time conditions.

[0047] The aforementioned specific order of current harmonics, together with the fundamental magnetic field of the permanent magnet, can generate radial electromagnetic force components of spatial order 0 and 2p in the air gap. Among them, the 0th order electromagnetic force acts directly on the radial direction of the stator teeth and is an important source of excitation for electromagnetic vibration of the motor.

[0048] Therefore, after calculating the current harmonics, based on the known flux linkage distribution of the motor, the magnetic field expression of the permanent magnet, and the Park transform model, the extracted 5th and 7th harmonics are introduced into the air gap magnetic field coupling relationship. The radial electromagnetic force generated after introducing the dead zone is obtained through Fourier expansion. ; In the formula, B svi0 B svil B svm0 and B svml Z represents the amplitude of the radial air gap magnetic flux density generated by the stator harmonic current; p is the number of stator slots; μ0 is the number of pole pairs of the motor; and μ0 is the vacuum permeability. For mechanical angle; v, , It is the order; This refers to the rotor's mechanical angular velocity; The initial spatial phase angle of the rotor permanent magnet main pole magnetic flux density relative to the stator reference coordinate system; It is the fundamental magnetic flux density of the permanent magnet's main pole.

[0049] Finally, different dead zone times were obtained. The corresponding 0th order electromagnetic force amplitude F0 ( ) and 2p-order electromagnetic force amplitude F2 ( ) etc. For example Figures 7-8 As shown.

[0050] Based on the inherent modes of the motor housing and stator structure, the vibration frequency range that the system is sensitive to can be obtained. Substituting the obtained radial electromagnetic force amplitude into the structural transmission characteristic H(ω), the corresponding vibration response amplitude can be calculated: A(Td) = F0( H(0th order) + F 2p ( H(2p order).

[0051] Furthermore, considering different rotational speeds, the dead time at different rotational speeds n is given. The relationship between the influence of vibration and noise is studied, and a simple mathematical form is introduced to describe the dead zone optimization principle.

[0052] Taking the 0th order as an example, the 5th / 7th harmonics caused by the dead zone interact with the magnetic field of the permanent magnet, generating a 0th order electromagnetic force mainly concentrated around 6f1 and its harmonics. Therefore, the main excitation frequency of the 0th order electromagnetic force is: .

[0053] As the rotational speed n increases, f F0 The linear increase makes it easier to approach certain intrinsic modal frequencies f of the stator structure. m,k This leads to vibration amplification.

[0054] Treating the zeroth-order electromagnetic force as a structural excitation, the amplitude of the stator vibration response is expressed as: ; Wherein, H0(f F0 F0(n,T) is the frequency response function of the zeroth order radial vibration. d The amplitude of the 0th order electromagnetic force (F0) varies with rotational speed and dead time; F0 is proportional to the amplitudes of the 5th and 7th harmonic currents (I5 and I7), and also varies with the dead time (T). d It increases as it grows.

[0055] Therefore, at different motor speeds, the frequencies of harmonic currents and electromagnetic forces vary with the electrical frequency, resulting in significant differences in their excitation effect on the motor structure. Specifically, at the same speed n, the vibration amplitude A(n,T) varies. d It will vary with the dead time T d The change is monotonically increasing; however, at different speeds, H0(f) F0 The different values ​​of (n) result in different allowable dead zone ranges for each speed: In the low-speed region, the change in dead time has a relatively small impact on vibration. F0 (n) When the frequency is far from the main modal frequency, |H0| is small. Even if the dead time is slightly large, the vibration increase is still limited. At this time, a larger dead time is allowed to improve the robustness of the drive. In the medium-to-high speed range, the frequency of harmonic electromagnetic forces increases, making it easier to approach the inherent response frequency band of the stator structure, thus significantly increasing the vibration amplitude; at this time, f F0 (n) Approaching certain modal frequencies, |H0| increases significantly. If a larger dead time is still used at low speeds, A(n,T) d The dead time will increase rapidly, and the vibration may exceed the allowable range. At this time, it is necessary to reduce the dead time, and even combine compensation and harmonic suppression.

[0056] Figures 9-10 A comparison of the vibration spectra of the motor and noise at different dead times under a speed of 500 r / min is presented. Figures 11-12 A comparison of the vibration spectra of motor vibration and noise at different dead times under 1500 r / min is presented. It can be seen that, for the same dead time, the vibration increase is smaller at low speeds, while the vibration is significantly amplified at high speeds. Therefore, different dead time settings must be used for different speeds. However, using a fixed dead time cannot meet the vibration performance requirements of different operating conditions and may lead to a significant increase in electromagnetic vibration in certain operating ranges.

[0057] To ensure that the motor vibration does not exceed the target value across the entire speed range, this embodiment sets a speed-related vibration threshold A. lim (n) is the upper limit of vibration related to motor speed, used to limit the allowable vibration level at different speeds, and to optimize dead time based on this constraint.

[0058] The optimization problem is expressed as: ; In practical implementation, at several different rotational speeds n i Below, for the preset candidate dead time set {T d,j} Perform scanning or experimental measurement to obtain the corresponding vibration amplitude A(n) i ,T d,j ).

[0059] In practical implementation, at the same rotational speed, multiple candidate dead times are preset, and the preset candidate dead time set {T} is used to determine the dead time. d,j} Perform scanning or experimental measurement to obtain the corresponding vibration amplitude A(n) i ,T d,j Among all dead times that satisfy vibration constraints, selection is performed based on different speed ranges: Under low-speed conditions (such as when the speed does not exceed the set value), vibration is not sensitive to the dead zone, so a relatively large dead zone time T is selected. d,opt (n1), ensuring the safety margin of the switching device under the premise of satisfying vibration constraints; Under medium to high speed conditions (speed greater than or equal to a set speed threshold), the impact of dead time on electromagnetic vibration is significantly enhanced. Therefore, by comparing vibration amplitudes, the dead time T that minimizes vibration is selected. d,opt (n2), limiting vibration to not exceed A lim (n2).

[0060] The final result is a speed-dead-time data pair (n) i ,T d,opt (n i The continuous mapping function is obtained through interpolation or fitting, and the target dead time is directly called according to the current speed during online operation.

[0061] If dead zone compensation ΔT is introduced simultaneously d Or, for a 5th / 7th harmonic suppressor, the definition is further based on the above: ; The target compensation amount ΔT varies with rotational speed is obtained. d,opt (n), similarly forming ΔT d =g(n) relationship, so that dead time and compensation amount have clear target values ​​at different speeds.

[0062] The mapping model can be established using one of the following methods: a piecewise function model, a two-dimensional or three-dimensional lookup table model, a linear or nonlinear interpolation model, a fitting function based on the least squares method, or a mapping model based on a simple neural network; to obtain T d =f(n), ΔT d =g(n), which is the target dead time and dead compensation amount that vary with the rotational speed.

[0063] In actual control, the controller detects the rotational speed n in real time and determines the speed based on a pre-established T. d,opt (n) and ΔT d,opt (n) Look up or calculate the target dead zone parameters for the current operating condition and use them to update the dead zone time and compensation amount of the PWM module, so that the actual dead zone parameters are dynamically adjusted according to the motor operating state, thereby suppressing the harmonic electromagnetic force and electromagnetic vibration caused by the dead zone under different operating conditions.

[0064] If a vibration sensor is configured, the vibration amplitude A can be monitored in real time. meas , when A meas When the threshold is exceeded, a correction strategy is activated: T dnew =T dreal –k(A meas –A ref This enables closed-loop adaptive optimization of dead time.

[0065] Figure 13The changes in the motor vibration spectrum after adaptive speed-dead-zone setting and harmonic compensation are demonstrated. The peak values ​​of several key frequencies in the motor vibration spectrum decrease significantly, especially at the frequency corresponding to the 0th order radial electromagnetic force, where the vibration is significantly weakened. By adjusting the control parameters related to the characteristic harmonics, the motor vibration response can exhibit different trends, providing a verification basis for proposing a dead-zone setting method based on vibration constraints.

[0066] This embodiment provides an adaptive dead-time adjustment method for motor inverters to suppress electromagnetic vibration noise. Based on the rotational speed and an error voltage model of the dead-time, characteristic harmonic components in the phase current are calculated. These harmonic components include at least the 5th and 7th order characteristic current harmonics introduced by the dead-time. Based on the coupling relationship between the current harmonics and the air gap magnetic field of the permanent magnet, the radial electromagnetic force generated by the dead-time is calculated, including the 0th order radial electromagnetic force component acting on the stator structure. The vibration response amplitude of the motor is calculated based on the radial electromagnetic force and compared with a preset vibration threshold to evaluate the vibration response caused by the electromagnetic force and determine whether the vibration response meets the vibration performance requirements. When the vibration level exceeds the limit, a target dead-time setting parameter is generated based on the motor speed and the vibration response amplitude to adjust the inverter dead-time at different speeds, thereby keeping the vibration at each speed within the allowable range. The target dead-time setting parameter is applied to the inverter dead-time setting or dead-time compensation process, and the inverter dead-time is adjusted according to the target dead-time setting parameter to achieve adaptive dead-time setting. The above method can automatically adjust the dead time according to the difference in dead harmonic excitation under different speed conditions, avoid excessive vibration under high speed conditions, and at the same time take into account the driving stability under low speed conditions, significantly reducing the electromagnetic vibration and noise level of the motor.

[0067] The adaptive dead-time adjustment method for suppressing electromagnetic vibration noise in motor inverters provided in this embodiment has advantages such as ease of engineering implementation and wide applicability. It can be applied to various types of motor drive systems. A simple example is shown below: (1) Household appliances: including television and audio-visual equipment, fans, air conditioners, food processing machines, beauty tools, range hoods, etc.

[0068] (2) Computer and peripheral equipment field: including computers (drives, fans, etc.), printers, plotters, optical drives, CD burners, etc.

[0069] (3) Industrial production field: including industrial drive devices, material processing systems, automation equipment, robots, etc.

[0070] (4) Automotive field: including permanent magnet starters, wiper motors, door lock motors, seat lifting motors, sunshade motors, washer pump motors, tape recorder motors, window lifting motors, radiator cooling fan motors, air conditioning motors, antenna lifting motors, oil pump motors, etc.

[0071] (5) Public life sector: including clocks, beauty machines, vending machines, ATMs, banknote counters, etc.

[0072] (6) Transportation sector: including trams, aircraft auxiliary equipment, ships, etc.

[0073] (7) Aerospace field: including rockets, satellites, spacecraft, space shuttles, etc.

[0074] (8) Defense field: including tanks, missiles, submarines, aircraft, etc.

[0075] (9) Medical field: including dental drills, artificial hearts, medical devices, etc.

[0076] (10) Power generation: including wind power generation, waste heat power generation, small hydropower generation, generators for small internal combustion generator sets, and auxiliary exciters for large generators, etc.

[0077] Example 2 This embodiment provides an adaptive dead-time adjustment system for motor inverters to suppress electromagnetic vibration noise, including: The model building module is configured to build an error voltage model based on dead time; The harmonic calculation module is configured to obtain the current harmonics in the phase current based on the current speed of the motor and using an error voltage model. The electromagnetic force calculation module is configured to obtain the radial electromagnetic force based on the current harmonics and the corresponding generated air gap magnetic flux density; The evaluation module is configured to determine the vibration response amplitude based on the radial electromagnetic force amplitude and compare the vibration response amplitude with a preset vibration threshold. The adjustment module is configured to determine the target dead time and dead time compensation amount based on the current speed of the motor when the vibration response amplitude is greater than the vibration threshold, thereby adjusting the inverter dead time.

[0078] It should be noted that the above modules correspond to the steps described in Embodiment 1, and the examples and application scenarios implemented by the above modules and the corresponding steps are the same, but are not limited to the content disclosed in Embodiment 1. It should also be noted that the above modules, as part of the system, can be executed in a computer system such as a set of computer-executable instructions.

[0079] It should be noted that the specific terminology used in the above embodiments is only used to describe specific embodiments and is not intended to limit the scope of protection of this disclosure. Unless otherwise specified, the singular form also includes the plural form. Unless expressly limited, the terms "comprising," "including," "having," etc., used in this specification are non-exclusive terms, indicating that other elements may be included without excluding the presence of other elements.

[0080] The structural terms such as "module," "unit," and "component" used in the above embodiments can be implemented through software, hardware, or a combination of both; the way their functions are implemented does not constitute a limitation of this disclosure. In the system implementation of this disclosure, each functional module can be physically independent, or multiple functions of this disclosure can be implemented by the same processor, controller, or program instructions.

[0081] The terms "connection," "linking," and "coupling" used in the above embodiments should be interpreted broadly, referring to direct or electrical connections as well as indirect connections via an intermediate medium; they can be fixed, detachable, or movable connections. Those skilled in the art can understand the specific meaning of these terms in this specification based on the actual situation.

[0082] In the above embodiments, terms such as permanent magnet synchronous motor, current harmonics, electromagnetic force, spatial order, and vibration frequency should be understood in the conventional sense in the technical field. These terms are only used to facilitate the description of specific embodiments and should not be construed as limiting this disclosure.

[0083] The terms “current harmonics,” “voltage error,” “electromagnetic force harmonics,” and “spatial order” mentioned in the above embodiments are used to describe the influence of dead time on the electromagnetic behavior of the motor. Their mathematical expressions, Fourier expansion forms, or frequency relationships are all forms that can be understood by those skilled in the art and do not constitute a limitation on specific models or solution methods.

[0084] The harmonic suppression methods in the above embodiments can be implemented by control programs of hardware platforms such as DSP, MCU, and FPGA, or in virtual controllers, simulation environments, or software systems. Their specific code structure, execution frequency, or register settings do not affect the scope of protection of this invention.

[0085] In further embodiments, the following is also provided: An electronic device includes a memory and a processor, as well as computer instructions stored in the memory and running on the processor, wherein the computer instructions, when executed by the processor, perform the method described in Embodiment 1. For brevity, further details are omitted here.

[0086] It should be understood that in this embodiment, the processor can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc.

[0087] Memory may include read-only memory and random access memory, and provides instructions and data to the processor. A portion of memory may also include non-volatile random access memory. For example, memory may also store information about the device type.

[0088] A computer-readable storage medium for storing computer instructions, which, when executed by a processor, perform the method described in Embodiment 1.

[0089] The method in Example 1 can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor. The software modules can reside in readily available storage media in the field, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, a detailed description is not provided here.

[0090] A computer program product includes a computer program that, when executed by a processor, implements the method described in Embodiment 1.

[0091] The present invention also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions included in program modules, which execute in a device on a target real or virtual processor to perform the processes / methods described above. Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc., that perform specific tasks or implement specific abstract data types. In various embodiments, the functionality of program modules can be combined or divided among program modules as needed. The machine-executable instructions for the program modules can execute within a local or distributed device. In a distributed device, the program modules can reside in both local and remote storage media.

[0092] The computer program code used to implement the methods of the present invention may be written in one or more programming languages. This computer program code may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the computer or other programmable data processing device, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a computer, partially on a computer, as a stand-alone software package, partially on a computer and partially on a remote computer, or entirely on a remote computer or server.

[0093] In the context of this invention, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer-readable media, and the like. Examples of signals may include electrical, optical, radio, sound, or other forms of propagation signals, such as carrier waves, infrared signals, etc.

[0094] Those skilled in the art will recognize that the units and algorithm steps described in connection with the various examples of this embodiment can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention.

[0095] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for adaptive adjustment of dead-time of motor inverter to suppress electromagnetic vibration noise, characterized in that, The method comprises the following steps: a dead-time-based error voltage model is constructed; a current harmonic in a phase current is obtained according to the current speed of the motor and the error voltage model; a radial electromagnetic force is obtained according to the current harmonic and the corresponding generated air gap magnetic flux density; a vibration response amplitude is determined according to the amplitude of the radial electromagnetic force, and the vibration response amplitude is compared with a preset vibration threshold value; when the vibration response amplitude is greater than the vibration threshold value, a target dead time and a dead time compensation amount are determined according to the current speed of the motor, so as to adjust the dead time of the inverter.

2. The dead-time adaptive adjustment method of the motor inverter for suppressing electromagnetic vibration noise according to claim 1, characterized in that, The error voltage model is: ； wherein is the DC bus voltage, is the electrical angular frequency, is the phase angle determined by the stator resistance and inductance; is the frequency; n is the rotational speed.

3. The dead-time adaptive adjustment method of the motor inverter for suppressing electromagnetic vibration noise according to claim 1, characterized in that, The phase current is: ； ； ； wherein, R is the stator resistance, L is the stator equivalent inductance; a is A, B, C three-phase; , and are the amplitudes of the fundamental, 5th current harmonic, 7th current harmonic; , and are the load impedance angles of the fundamental, 5th current harmonic, 7th current harmonic; Z is the load impedance; V is the DC bus voltage, n is the rotating speed.

4. The dead-time adaptive adjustment method of the motor inverter for suppressing electromagnetic vibration noise according to claim 3, characterized in that, The current harmonic includes a harmonic with a frequency of (6k±1)f1, k is a positive integer, and f1 is the motor frequency.

5. The dead-time adaptive adjustment method of a motor inverter for suppressing electromagnetic vibration noise according to claim 1, characterized in that, The radial electromagnetic force is: ； where B svi0 , B svil , B svm0 and B svml are the amplitude of the radial air-gap flux density generated by the stator harmonic currents, Z is the number of stator slots; p is the number of motor pole pairs, μ0 is the vacuum permeability; is the mechanical angle; v, , is the order; is the rotor mechanical angular velocity; is the initial spatial phase angle of the rotor permanent magnet main pole flux density relative to the stator reference coordinate system; is the permanent magnet main pole fundamental flux density.

6. The dead-time adaptive adjustment method of a motor inverter for suppressing electromagnetic vibration noise according to claim 1, characterized in that, At the same speed, a preset candidate dead time is selected from all dead times meeting the vibration constraint according to the speed interval in which the current speed of the motor is located: at a low speed working condition, a relatively large dead time is selected; at a medium-high speed working condition, a dead time that minimizes the vibration is selected, and a corresponding dead time compensation amount is applied.

7. A motor inverter dead time adaptive adjustment system for suppressing electromagnetic vibration noise, characterized by, The method comprises the following steps: a model construction module configured to construct a dead-time-based error voltage model; a harmonic calculation module configured to obtain a current harmonic in a phase current according to the current speed of the motor and the error voltage model; an electromagnetic force calculation module configured to obtain a radial electromagnetic force according to the current harmonic and the corresponding generated air gap magnetic flux density; an evaluation module configured to determine a vibration response amplitude according to the amplitude of the radial electromagnetic force, and compare the vibration response amplitude with a preset vibration threshold value; an adjustment module configured to, when the vibration response amplitude is greater than the vibration threshold value, determine a target dead time and a dead time compensation amount according to the current speed of the motor, so as to adjust the dead time of the inverter.

8. An electronic device, comprising: A computer program product is provided, which comprises a memory and a processor, and computer instructions stored in the memory and executed on the processor, and when the computer instructions are executed by the processor, the method of any one of claims 1-6 is completed.

9. A computer-readable storage medium, characterized in that, A computer program product is provided, which comprises a memory and a processor, and computer instructions stored in the memory and executed on the processor, and when the computer instructions are executed by the processor, the method of any one of claims 1-6 is completed.

10. A computer program product, characterised in that, A computer program product is provided, which comprises a memory and a processor, and computer instructions stored in the memory and executed on the processor, and when the computer instructions are executed by the processor, the method of any one of claims 1-6 is completed.

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