Test estimation method and device for key high-order mode of permanent magnet motor stator

Abstract

The invention relates to the technical field of permanent magnet motors, and discloses a test estimation method and device for a key high-order mode of a permanent magnet motor stator, and the method comprises the steps: adjusting the carrier frequency of a frequency converter in a preset frequency range, and calculating the current amplitude and noise amplitude of a motor under a plurality of preset carrier frequencies; constructing a frequency response function mathematical model, and calculating a parameter value of the model under each preset carrier frequency based on the current amplitude and the noise amplitude under each preset carrier frequency; and drawing a modal frequency response curve corresponding to the high-order modal according to the parameter values of the model, and determining modal parameters corresponding to the high-order modal according to the modal frequency response curve. According to the method, the motor higher harmonic theory technology and the vibration mode theory technology are combined to realize extraction of key high-order modal parameters after motor assembly, the problems of insufficient excitation energy, insufficient excitation bandwidth and difficult vibration mode extraction when the high-order key modal is obtained by a traditional modal test method are effectively avoided, the requirement on hardware equipment is reduced, and the test efficiency is improved. And the method has extremely high engineering application value.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet motor technology, specifically to a method and apparatus for experimental estimation of key high-order modes of a permanent magnet motor stator. Background Technology

[0002] The key high-order modes (0th and 2p, where p is the number of pole pairs) of the permanent magnet motor stator have a decisive influence on the electromagnetic vibration and noise performance of the motor system, affecting the smoothness of motor operation and lifespan. They are one of the core concerns in motor electromagnetic design and structural resonance suppression, and are important parameters that motor vibration and noise simulation and testing personnel need to pay attention to.

[0003] The key high-order modes (0th and 2p) of permanent magnet motor stators are distributed in high frequency bands and have small amplitudes, making them easily submerged by electromagnetic noise and mechanical background vibrations. Therefore, neither the hammer method nor the exciter method can effectively elicit a response in this frequency band, resulting in an inaccurately identifiable frequency response function. Furthermore, the compact structure of the motor stator means that the added mass of the sensors can easily alter the dynamic characteristics of the system, especially in small and medium-sized motors. According to modal testing theory, obtaining the key high-order modes requires a densely packed sensor matrix on the stator, which significantly limits the installation of contact accelerometer sensors. Therefore, current modal testing techniques cannot directly measure the key high-order modes of motor stators. Summary of the Invention

[0004] In view of this, the present invention provides a method and apparatus for experimental estimation of key high-order modes of permanent magnet motor stator, so as to solve the problem that existing modal testing techniques are difficult to directly measure key high-order modes of motor stator.

[0005] In a first aspect, the present invention provides an experimental estimation method for key high-order modes of a permanent magnet motor stator, wherein the carrier frequency of the frequency converter is adjusted to the initial carrier frequency to enable the permanent magnet motor to operate at its rated speed. The method includes:

[0006] Adjust the carrier frequency of the inverter within a preset frequency range, and calculate the current amplitude and noise amplitude of the permanent magnet motor under multiple preset carrier frequencies;

[0007] Construct a mathematical model of the frequency response function, and calculate the parameter values ​​of the mathematical model of the frequency response function at each preset carrier frequency based on the current amplitude and noise amplitude at each preset carrier frequency;

[0008] Based on the parameter values ​​of the mathematical model of the frequency response function, plot the modal frequency response curves corresponding to the higher-order modes, and determine the modal parameters corresponding to the higher-order modes based on the modal frequency response curves.

[0009] The experimental estimation method for key high-order modes of permanent magnet motor stator provided by this invention combines motor high-order harmonic theory and vibration mode theory to extract key high-order modal parameters after motor assembly. It effectively avoids the problems of insufficient excitation energy, insufficient excitation bandwidth, and difficulty in mode shape extraction when obtaining high-order key modes by traditional modal testing methods, reduces the requirements for hardware equipment, and has extremely high engineering application value.

[0010] In one optional implementation, the carrier frequency of the inverter is adjusted within a preset frequency range, and the current amplitude and noise amplitude of the permanent magnet motor are calculated at multiple preset carrier frequencies, including:

[0011] Adjust the carrier frequency of the frequency converter within a preset frequency range to obtain current and noise signals;

[0012] Fourier transforms are performed on the current signal and the noise signal respectively to obtain the current spectrum and the noise spectrum;

[0013] The current amplitude corresponding to each preset carrier frequency is determined based on the current spectrum, and the noise amplitude corresponding to each preset carrier frequency is determined based on the noise spectrum.

[0014] In one optional implementation, acquiring the current signal and the noise signal includes:

[0015] The current signal is obtained using an ammeter, and the noise signal on the motor surface is obtained using a non-contact noise test sensor.

[0016] The experimental estimation method for key high-order modes of permanent magnet motor stators provided by this invention accurately obtains the current and noise amplitudes at different frequencies by adjusting the carrier frequency of the frequency converter and combining Fourier transform, providing a reliable data foundation for modal analysis. It uses a non-contact noise sensor to collect noise signals, avoiding contact interference and ensuring that the noise signals are real and reliable. From frequency adjustment to signal processing, a complete scientific process is constructed to support the subsequent calculation of the frequency response function mathematical model and the determination of modal parameters, thus promoting the efficient and accurate conduct of high-order mode tests of permanent magnet motor stators.

[0017] In one optional implementation, based on the current amplitude and noise amplitude at each preset carrier frequency, the parameter values ​​of the frequency response function mathematical model at each preset carrier frequency are calculated, including:

[0018] The spatiotemporal distribution relationship between the radial electromagnetic force and current in the sideband is derived based on electromagnetic theory, and the mapping relationship between the time order and higher-order mode shapes is determined by using the spatiotemporal distribution relationship between the radial electromagnetic force and current in the sideband.

[0019] The higher-order vibration mode to which each preset carrier frequency belongs is determined based on the mapping relationship between time order and higher-order vibration mode.

[0020] Based on the higher-order mode shape of each preset carrier frequency, and the corresponding current amplitude and noise amplitude, the parameter values ​​of the corresponding frequency response function mathematical model are calculated using the corresponding frequency response function mathematical model.

[0021] The experimental estimation method for key high-order modes of permanent magnet motor stators provided by this invention uses electromagnetic theory to derive the spatiotemporal distribution relationship between sideband radial electromagnetic force and current, establishes a mapping between time order and high-order mode shapes, can accurately classify the mode shape to which the carrier frequency belongs, constructs the corresponding frequency response function mathematical model and combines it with current and noise amplitude calculation parameters, so that the calculation of frequency response function mathematical model parameters is deeply related to the actual mode shape characteristics of the motor, improving the pertinence and accuracy of parameter calculation, laying a solid foundation for subsequent accurate identification of high-order modes of permanent magnet motor stators and mastering their vibration characteristics, and making modal analysis more consistent with the actual physical mechanism of motor operation.

[0022] In one optional implementation, the mapping relationship between time order and higher-order mode shapes is determined using the spatiotemporal distribution relationship between sideband radial electromagnetic force and current, including:

[0023] Based on Maxwell's tensor method, the frequency characteristics of the sideband radial electromagnetic force considering current harmonics are determined.

[0024] The time order is divided into a first interval corresponding to the 0th order mode shape and a second interval corresponding to the 2p order mode shape, so as to determine the mapping relationship between the time order and the higher order mode shape.

[0025] The experimental estimation method for key high-order modes of permanent magnet motor stator provided by this invention uses Maxwell's tensor method to clarify the frequency characteristics of radial electromagnetic force in the sideband, and then divides the time order into intervals corresponding to the 0th and 2p-order vibration modes. This can accurately and clearly establish the correlation between the time order and the high-order vibration modes, so that the subsequent modal analysis has a reliable basis and can accurately identify the high-order vibration modes of the motor stator at different time orders.

[0026] In one optional implementation, based on the higher-order mode shape of each preset carrier frequency and the corresponding current and noise amplitudes, the parameter values ​​of the corresponding frequency response function mathematical model are calculated using the corresponding frequency response function mathematical model, including:

[0027] The force wave Fourier spectrum corresponding to the higher-order vibration mode is determined based on the calculation formula of the higher-order mode.

[0028] Based on the residue theorem and the Fourier spectrum of force waves, the expression of the mathematical model of the frequency response function in the frequency domain is determined.

[0029] Based on the current amplitude and noise amplitude, the parameter values ​​of the frequency response function mathematical model corresponding to each carrier frequency are calculated using the expression of the frequency response function mathematical model in the frequency domain. The parameter values ​​of the frequency response function mathematical model include: natural frequency and damping ratio.

[0030] In one alternative implementation, the expression of the frequency response function mathematical model in the frequency domain is determined based on the force wave Fourier spectrum, using the residue theorem, including:

[0031] Based on the vibration theory of single-degree-of-freedom systems, the expression for the system transfer function in the complex frequency domain is:

[0032]

[0033] Where H(s) represents the system transfer function, m represents the system mass, c represents the system damping, k represents the system stiffness, s represents the complex frequency domain variables, and p, p * Representing the poles of the system (a pair of conjugate complex numbers), R, R * This represents the residue at the corresponding pole.

[0034] By replacing the complex frequency domain variables with frequency domain variables and applying the residue theorem, we obtain the expression for the mathematical model of the frequency response function in the frequency domain:

[0035]

[0036] Where j represents an imaginary number, and ω represents the vibration frequency of the motor.

[0037] The present invention provides an experimental estimation method for key high-order modes of permanent magnet motor stators. It determines the Fourier spectrum of force waves in high-order mode shapes, clarifies the frequency domain expression of the mathematical model of the frequency response function by combining the residue theorem, and then calculates parameters using current and noise amplitude to accurately calculate key parameters such as natural frequency and damping ratio. These parameters serve as the core basis for in-depth analysis of motor modal characteristics, enabling engineers to accurately grasp the motor vibration law and providing strong data support for optimizing motor design and suppressing undesirable vibrations.

[0038] Secondly, the present invention provides a test estimation device for key high-order modes of a permanent magnet motor stator, which adjusts the carrier frequency of the frequency converter to the initial carrier frequency so that the permanent magnet motor operates at its rated speed. The device includes:

[0039] The data acquisition and extraction module is used to adjust the carrier frequency of the frequency converter within a preset frequency range and calculate the current amplitude and noise amplitude of the permanent magnet motor under multiple preset carrier frequencies.

[0040] The parameter calculation module is used to construct a mathematical model of the frequency response function and calculate the parameter values ​​of the mathematical model of the frequency response function at each preset carrier frequency based on the current amplitude and noise amplitude at each preset carrier frequency.

[0041] The higher-order modal parameter determination unit is used to plot the modal frequency response curves corresponding to the higher-order modes based on the parameter values ​​of the frequency response function mathematical model, and to determine the modal parameters corresponding to the higher-order modes based on the modal frequency response curves.

[0042] Thirdly, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to perform the method described in the first aspect or any corresponding embodiment thereof.

[0043] Fourthly, the present invention provides a computer-readable storage medium storing computer instructions for causing a computer to perform the method described in the first aspect or any corresponding embodiment thereof. Attached Figure Description

[0044] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0045] Figure 1 This is a flowchart illustrating the experimental estimation method for key higher-order modes of a permanent magnet motor stator according to an embodiment of the present invention.

[0046] Figure 2 This is a flowchart illustrating an experimental estimation method for key higher-order modes of a permanent magnet motor stator according to an embodiment of the present invention.

[0047] Figure 3 This is a schematic diagram of the 0th-order mode frequency response curve in a specific embodiment of the experimental estimation method for key high-order modes of the permanent magnet motor stator according to an embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of the frequency response curve of the 2p-order mode in a specific embodiment of the experimental estimation method for the key high-order modes of the stator of a permanent magnet motor according to an embodiment of the present invention.

[0049] Figure 5 This is a schematic diagram of the simulated mode shape corresponding to the 0th order mode in a specific embodiment of the experimental estimation method for key high-order modes of the permanent magnet motor stator according to an embodiment of the present invention;

[0050] Figure 6 This is a schematic diagram of the simulated mode shape corresponding to the 2p-order mode in a specific embodiment of the experimental estimation method for the key high-order modes of the permanent magnet motor stator according to an embodiment of the present invention;

[0051] Figure 7 This is a structural block diagram of a test estimation device for key high-order modes of a permanent magnet motor stator according to an embodiment of the present invention;

[0052] Figure 8 This is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] This invention provides an experimental estimation method for key high-order modes of a permanent magnet motor stator. By combining motor high-order harmonic theory and vibration mode theory, the key high-order mode parameters after motor assembly are extracted, thereby achieving accurate and efficient measurement of the key high-order modes of the permanent magnet motor stator.

[0055] According to an embodiment of the present invention, an experimental estimation method for key high-order modes of a permanent magnet motor stator is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0056] This embodiment provides an experimental estimation method for key higher-order modes of a permanent magnet motor stator, which can be used in the aforementioned computer system. Figure 1 This is a flowchart of an experimental estimation method for key higher-order modes of a permanent magnet motor stator according to an embodiment of the present invention, such as... Figure 1 As shown, the process includes the following steps:

[0057] Step S101: Adjust the carrier frequency of the inverter within the preset frequency range, and calculate the current amplitude and noise amplitude of the permanent magnet motor under multiple preset carrier frequencies.

[0058] Specifically, before using this method to measure the key high-order modes of the permanent magnet motor stator, the carrier frequency of the frequency converter needs to be adjusted to the initial carrier frequency so that the permanent magnet motor operates at its rated speed. This carrier frequency f can be adjusted by changing the switching frequency of the frequency converter. cOnce the preset initial value is reached, the permanent magnet motor is controlled to operate at its rated speed. The fundamental frequency is calculated based on the motor speed. Inside the motor, the stator windings, when energized with alternating current, generate a rotating magnetic field. The fundamental frequency is the frequency of the alternating current itself; for example, household alternating current is 50Hz. If the motor is connected to household alternating current, its fundamental frequency can be considered to be 50Hz. The relationship between motor speed and fundamental frequency is as follows: Where n0 represents the motor speed (unit: revolutions per minute), f0 represents the fundamental frequency (unit: Hz), and p represents the number of pole pairs of the motor.

[0059] Starting from the initial carrier frequency, gradually increase the carrier frequency f of the inverter. c It also collects current and noise signals in real time, and determines the current amplitude and noise amplitude corresponding to each preset carrier frequency by processing the current and noise signals.

[0060] Step S102: Construct a mathematical model of the frequency response function, and calculate the parameter values ​​of the mathematical model of the frequency response function at each preset carrier frequency based on the current amplitude and noise amplitude at each preset carrier frequency.

[0061] Specifically, based on the electromagnetic-vibration coupling mechanism of the motor, a transmission relationship model (basic form of frequency response function) is established between "current excitation (reflecting the characteristics of sideband electromagnetic force)" and "noise response (reflecting the vibration characteristics of key stator modes)". Under this model, the mathematical mapping relationship between excitation and response is clearly defined.

[0062] Using the current amplitude (excitation intensity quantization) and noise amplitude (vibration response quantization) collected at each preset carrier frequency as input, and substituting them into the frequency response function mathematical model, the key modal parameters (natural frequency, damping ratio and other modal characteristics) are solved through signal processing and modal analysis algorithms (such as fast Fourier transform, amplitude-frequency / phase-frequency characteristic extraction, residue theorem application, etc.), providing a mathematical model for quantitative basis for modal parameter identification.

[0063] Step S103: Plot the modal frequency response curves corresponding to the higher-order modes based on the parameter values ​​of the mathematical model of the frequency response function, and determine the modal parameters corresponding to the higher-order modes based on the modal frequency response curves.

[0064] Specifically, the modal frequency response curve is the modal frequency response curve corresponding to the higher-order modes in the critical space. The higher-order modes in the critical space are generally of order 0 and 2p, which are only examples and are not limited to this. The horizontal axis of the modal frequency response curve represents the "frequency of excitation or response"; the vertical axis represents the "amplitude of the mathematical model of the frequency response function", reflecting the strength of the motor's response to excitations of different frequencies.

[0065] The modal parameters corresponding to higher-order modes include, but are not limited to: natural frequency (the frequency with the highest amplitude in the modal frequency response curve), damping ratio, mode shape, and attenuation coefficient. The methods for determining each modal parameter are mature existing technologies and will not be elaborated here.

[0066] The experimental estimation method for key high-order modes of permanent magnet motor stator provided in this embodiment combines motor high-order harmonic theory and vibration mode theory to extract key high-order modal parameters after motor assembly. It effectively avoids the problems of insufficient excitation energy, insufficient excitation bandwidth, and difficulty in mode shape extraction when obtaining high-order key modes by traditional modal testing methods, reduces the requirements for hardware equipment, and has extremely high engineering application value.

[0067] This embodiment provides an experimental estimation method for key higher-order modes of a permanent magnet motor stator, which can be used in the aforementioned computer system. Figure 2 This is a flowchart of an experimental estimation method for key higher-order modes of a permanent magnet motor stator according to an embodiment of the present invention, such as... Figure 2 As shown, the process includes the following steps:

[0068] Step S201: Adjust the carrier frequency of the inverter within the preset frequency range, and calculate the current amplitude and noise amplitude of the permanent magnet motor under multiple preset carrier frequencies.

[0069] Specifically, step S201 includes:

[0070] Step S2011: Adjust the carrier frequency of the inverter within the preset frequency range to obtain the current signal and noise signal.

[0071] Specifically, for the sideband electromagnetic force distribution of the inverter's harmonic power supply, according to Maxwell's tensor method, neglecting the influence of the tangential component, the radial electromagnetic force per unit area is expressed as:

[0072]

[0073] Among them, B r denoted by , μ0 represents the radial air gap magnetic flux density, μ0 represents the vacuum permeability, θ represents the mechanical angle in the circumferential direction of the motor, and t represents time.

[0074] Radial air gap magnetic flux density B r Expanded representation:

[0075] B r (θ,t)=[B mv (θ,t)+B mμ (θ,t)]λ (2)

[0076] Among them, B mv B represents the v-th air gap magnetic flux density component of the stator winding magnetic field; mμLet μ represent the μ-th air gap magnetic flux density component of the rotor permanent magnet magnetic field, and let μ = 2v⁻¹ (v = 1, 2, 3, ...); let λ represent the relative air gap permeability considering stator slotting, and let:

[0077]

[0078] Where λ0 represents the average air gap permeability; η is the tooth harmonic order; and z represents the number of stator slots.

[0079] Substituting equations (2) and (3) into equation (1), we obtain the expression for the radial electromagnetic force density in the frequency band considering harmonic currents:

[0080]

[0081] Where N represents the number of turns of the stator coil; ζ represents the stator winding coefficient; p is the number of pole pairs of the motor; N t ωp is the greatest common divisor of the number of pole pairs p and the number of slots z; ω0 is the fundamental angular frequency of the stator; ω0 μ I is the stator harmonic angular frequency; d / q This represents the current harmonics along the dq axis.

[0082] According to formula (4), when the carrier frequency is f c At that time, the frequency of the sideband electromagnetic force generated by the inverter current harmonics is f. c The characteristic response peak value of ±μf0; by changing f in small steps within a preset frequency range. c The value of is repeatedly acquired through a microphone measuring point on the surface of the motor to obtain the noise signal. Since the excitation force F∈I 2 Therefore, it is necessary to collect current harmonic signals.

[0083] In some alternative implementations, acquiring the current signal and the noise signal includes:

[0084] The current signal is obtained using an ammeter, and the noise signal on the motor surface is obtained using a non-contact noise test sensor.

[0085] Specifically, current clamps can be used to read current signals. For non-contact noise testing sensors, a sound level meter can be selected. The sound level meter consists of a microphone, a preamplifier, a signal processor, and a display screen. The microphone is placed near the noise measurement point on the surface of the motor to obtain noise signals.

[0086] Step S2012: Perform Fourier transforms on the current signal and the noise signal respectively to obtain the current spectrum and the noise spectrum.

[0087] Specifically, Fourier transforms are performed on the current signal and the noise signal respectively to convert the time-domain signal into a frequency-domain signal, thus obtaining the current spectrum and the noise spectrum. Fourier transform is a mature existing technology and will not be elaborated here.

[0088] Step S2013: Determine the current amplitude corresponding to each preset carrier frequency based on the current spectrum, and determine the noise amplitude corresponding to each preset carrier frequency based on the noise spectrum.

[0089] Specifically, find the frequency f from the current spectrum. ±μ =f c The current amplitude I corresponding to ±μf0 (μ=2,4,6,...) ±μ From the noise spectrum, find the frequency f. ±μ =f c The noise amplitude A corresponding to ±μf0 (μ=1,3,5,...) μ .

[0090] The experimental estimation method for key high-order modes of permanent magnet motor stators provided in this embodiment accurately obtains the current and noise amplitudes at different frequencies by adjusting the carrier frequency of the frequency converter and combining Fourier transform, providing a reliable data foundation for modal analysis. It uses a non-contact noise sensor to collect noise signals, avoiding contact interference and ensuring that the noise signals are real and reliable. From frequency adjustment to signal processing, a complete scientific process is constructed to support the subsequent calculation of the frequency response function mathematical model and the determination of modal parameters, thus promoting the efficient and accurate conduct of high-order mode tests of permanent magnet motor stators.

[0091] Step S202: Construct a mathematical model of the frequency response function, and calculate the parameter values ​​of the mathematical model of the frequency response function at each preset carrier frequency based on the current amplitude and noise amplitude at each preset carrier frequency.

[0092] Specifically, step S202 includes:

[0093] Step S2021: Based on electromagnetic theory, the spatiotemporal distribution relationship between the sideband radial electromagnetic force and current is derived, and the mapping relationship between the time order and higher-order vibration modes is determined using the spatiotemporal distribution relationship between the sideband radial electromagnetic force and current.

[0094] Specifically, according to formula (4), the frequency of the sideband electromagnetic force is equal to the harmonic frequency near the carrier frequency. Therefore, considering the characteristic frequency of the sideband electromagnetic force generated by the inverter current harmonics, it is ω. μ ±μω0, where ω μ Let ω be the carrier angular frequency, ω0 be the fundamental angular frequency, and μ be the harmonic order. The amplitude of the electromagnetic force is essentially the result of the "in-phase superposition" of the stator and rotor magnetic fields. If the spatial phase difference between the two magnetic fields is 0 or 2π (in-phase), the electromagnetic forces will superimpose, and the amplitude will increase; if the phase difference is π (out of phase), the electromagnetic forces will cancel each other out, and the amplitude will decrease or even become zero. Therefore, the amplitude (non-zero amplitude) of the characteristic frequency of the sideband electromagnetic force is expressed as:

[0095] p-vNt =0

[0096] p+vN t =2p (5)

[0097] Where, N t represents the greatest common divisor of the number of pole pairs and the number of slots; v represents the v-th air gap magnetic flux density harmonic caused by the magnetic fields acting on the stator and rotor of the motor.

[0098] According to formulas (4) and (5), the spatiotemporal distribution relationship between the radial electromagnetic force and current in the sideband can be obtained as shown in Table 1. This is only an example and is not limited to this.

[0099] Table 1

[0100]

[0101] In an optional implementation, step S2011 above includes:

[0102] Step a1: Based on Maxwell's tensor method, determine the frequency characteristics of the sideband radial electromagnetic force considering current harmonics.

[0103] Specifically, based on Maxwell's tensor method and combined with electromagnetic theory analysis, the frequency characteristics of the sideband radial electromagnetic force considering current harmonics are obtained as shown in formula (4). For details, please refer to step S2011, which will not be repeated here.

[0104] Step a2: Divide the time order into the first interval corresponding to the 0th order mode shape and the second interval corresponding to the 2p order mode shape to determine the mapping relationship between the time order and the higher order mode shape.

[0105] Specifically, as shown in Table 1, based on formulas (4) and (5), the time order is divided into the first interval corresponding to the 0th order mode shape, including: f c ±3f1, the second interval corresponding to the 2p order mode includes: f c -5f1、f c -f1、f c +f1、f c +5f1. Referring to Table 1, determine the mapping relationship between time order and higher-order vibration modes: Time order f c The response of ±3f1 produces a higher-order mode shape of order 0; the time order f c -5f1、f c -f1、f c +f1、f c The response of +5f1 produces a higher-order mode shape of the 2p order.

[0106] The experimental estimation method for key high-order modes of permanent magnet motor stator provided in this embodiment uses Maxwell's tensor method to clarify the frequency characteristics of radial electromagnetic force in the sideband, and then divides the time order into intervals corresponding to the 0th and 2p-order vibration modes. This can accurately and clearly establish the correlation between the time order and the high-order vibration modes, so that the subsequent modal analysis has a reliable basis and can accurately identify the high-order vibration modes of the motor stator at different time orders.

[0107] Step S2022: Determine the higher-order vibration mode to which each preset carrier frequency belongs based on the mapping relationship between time order and higher-order vibration mode.

[0108] Specifically, based on the mapping relationship between time order and higher-order mode shapes, the higher-order mode shape to which each preset carrier frequency belongs, i.e., f, is obtained. c ±3f1 belongs to the 0th order higher-order vibration mode, f c -5f1、f c -f1、f c +f1、f c +5f1 is a higher-order vibration mode of the 2p order, and is only used as an example, but is not a limitation.

[0109] Step S2023: Based on the higher-order mode shape of each preset carrier frequency and the corresponding current amplitude and noise amplitude, calculate the parameter values ​​of the mathematical model of the frequency response function corresponding to each preset carrier frequency using the corresponding mathematical model of the frequency response function.

[0110] In an optional implementation, step S2023 above includes:

[0111] Step b1: Determine the force wave Fourier spectrum corresponding to the higher-order mode shape according to the calculation formula of the higher-order mode.

[0112] The frequency response function (FRF) represents the relationship between the acceleration spectrum and the force spectrum, and its expression is:

[0113]

[0114] Where A(jω) represents the acceleration Fourier spectrum (the noise spectrum obtained from the microphone measurement point); F(jω) represents the force Fourier spectrum; and the frequency response function represents the acceleration response characteristics of the system under unit force excitation in the frequency domain.

[0115] Based on formula (4), the parameters related to the motor are simplified to K (a constant value determined by the design), and the radial excitation of the motor can be expressed as:

[0116] F = KI 2 (7)

[0117] Where K represents the inherent parameters of the motor.

[0118] Substituting formula (7) into formula (6), the final mathematical model of the frequency response function is:

[0119] Step b2: Combining the residue theorem, determine the expression of the frequency response function mathematical model in the frequency domain based on the force wave Fourier spectrum.

[0120] In some alternative implementations, the expression of the frequency response function mathematical model in the frequency domain is determined based on the force wave Fourier spectrum, using the residue theorem, including:

[0121] Based on the vibration theory of single-degree-of-freedom systems, the expression for the system transfer function in the complex frequency domain is:

[0122]

[0123] Where H(s) represents the system transfer function, m represents the system mass, c represents the system damping, k represents the system stiffness, s represents the complex frequency domain variables, and p, p * Representing the poles of the system (a pair of conjugate complex numbers), R, R * This represents the residue at the corresponding pole.

[0124] By replacing the complex frequency domain variables with frequency domain variables and applying the residue theorem, we obtain the expression for the mathematical model of the frequency response function in the frequency domain:

[0125]

[0126] Where j represents an imaginary number, and ω represents the vibration frequency of the motor.

[0127] Step b3: Based on the current amplitude and noise amplitude, the parameter values ​​of the frequency response function mathematical model corresponding to each carrier frequency are calculated using the expression of the frequency response function mathematical model in the frequency domain. The parameter values ​​of the frequency response function mathematical model include: natural frequency and damping ratio.

[0128] Specifically, the current amplitude and noise amplitude collected by the test are arranged in ascending order of frequency to form a continuous signal. The excitation expression is obtained according to formula (7), and the parameter values ​​of the mathematical model of the frequency response function corresponding to each carrier frequency are calculated using the expression (6) of the frequency response function in the frequency domain. The pole p is directly related to the modal parameters of the system, p=-σ+jω d Where σ represents the attenuation coefficient, ω d The damped natural frequency, and the modal parameters determined based on the pole p, include: undamped natural frequency. Damping ratio Damped natural frequency

[0129] The experimental estimation method for key high-order modes of permanent magnet motor stators provided in this embodiment utilizes electromagnetic theory to derive the spatiotemporal distribution relationship between sideband radial electromagnetic force and current, establishing a mapping between time order and high-order mode shapes. This allows for accurate classification of the mode shape to which the carrier frequency belongs, construction of the corresponding frequency response function mathematical model, and calculation of parameters using current and noise amplitudes. This deeply correlates the calculation of frequency response function mathematical model parameters with the actual mode shape characteristics of the motor, improving the pertinence and accuracy of parameter calculations. This lays a solid foundation for subsequent accurate identification of high-order modes of the permanent magnet motor stator and understanding its vibration characteristics, making modal analysis more closely aligned with the actual physical mechanism of motor operation. By determining the Fourier spectrum of force waves in high-order mode shapes and clarifying the frequency domain expression of the frequency response function mathematical model using the residue theorem, and then calculating parameters using current and noise amplitudes, key parameters such as natural frequency and damping ratio are accurately calculated. These parameters serve as the core basis for in-depth analysis of motor modal characteristics, enabling engineers to accurately grasp the motor vibration laws and providing strong data support for optimizing motor design and suppressing undesirable vibrations.

[0130] Step S203: Plot the modal frequency response curves corresponding to the higher-order modes based on the parameter values ​​of the frequency response function mathematical model, and determine the modal parameters corresponding to the higher-order modes based on the modal frequency response curves. For details, please refer to [link to relevant documentation]. Figure 1 Step S103 of the illustrated embodiment will not be described again here.

[0131] In one specific embodiment, taking a 9-slot, 6-pole (pole pair number p=3) permanent magnet motor as an example, the key higher-order modes (0th order and 2p order) of its stator are tested and estimated. The specific process includes:

[0132] (1) The frequency bands of the 0th and 2p-order mode distributions of the motor stator were determined by finite element simulation technology.

[0133] (2) According to formula (4), when the carrier frequency is f c At that time, the frequency of the sideband electromagnetic force generated by the inverter current harmonics is f. c The characteristic response peak value of ±μf0; by changing f in small steps c The value of is obtained from the microphone measuring point on the surface of the motor to obtain the response parameters; in addition, according to formula (7), the excitation force F∈I 2 Therefore, it is necessary to collect current harmonic signals.

[0134] (3) According to Table 1, the time order f c -5f1、f c -f1、f c +f1、f c The response of +5f1 produces a higher-order mode shape of 2p; the time order f c The response of ±3f1 produces a higher-order mode of vibration of order 0.

[0135] (4) According to formulas (6) and (7), when f is changed c Since the motor's intrinsic parameter K does not change, it is assumed that at f c During the change process, there is always a constant excitation F inside the motor, which produces different A(jω) response results.

[0136] 4.1 The calculation process for the 0th order higher-order modes includes: According to Table 1 and formula (7), we can obtain:

[0137]

[0138] The composition expression for the 0th order force wave F(jω) is as follows:

[0139]

[0140] Construct the 0th order higher mode frequency response function according to equation (6), and solve the natural frequency and damping ratio of FRF according to equation (9).

[0141] 4.2 The calculation process for the 0th order higher-order modes includes: By analogy with formula (10), we can obtain:

[0142]

[0143] The composition expression for the 2p-order force wave F(jω) is as follows:

[0144]

[0145] Similarly, construct the 2p-order higher-order modal frequency response function according to equation (6), and solve the natural frequency and damping ratio of the FRF according to equation (9).

[0146] (5) Based on the calculation results, plot the frequency response curves of the 0th and 2p modes, as follows: Figure 3 The figure shows the frequency response curve of the 0th mode. The process of calculating the modal parameters based on this frequency response curve includes:

[0147] Estimate the peak frequency based on the frequency response curve: f peak ≈4385Hz.

[0148] Calculate the damping ratio bandwidth using the half-power method:

[0149] The left and right half-power points are found by interpolation: the left half-power frequency point f1≈4355Hz; the right half-power frequency point f2≈4420Hz.

[0150] Therefore, the damping ratio is:

[0151] Damped natural frequency (system natural frequency) f d =fpeak ≈4385Hz.

[0152] Undamped natural frequency

[0153] Attenuation coefficient σ=ζω n =2πf n ζ≈204rad / s.

[0154] Because the damping ratio of the system is extremely small at high frequencies, therefore f n with f d The differences are negligible.

[0155] pole

[0156] like Figure 4 The figure shows the frequency response curve of the 2p-order mode. The process of calculating the modal parameters based on this frequency response curve includes:

[0157] Estimate the peak frequency based on the frequency response curve: f peak ≈6885Hz.

[0158] Calculate the damping ratio bandwidth using the half-power method:

[0159] The left and right half-power points are found by interpolation: the left half-power frequency point f1≈6855Hz; the right half-power frequency point f2≈6910Hz.

[0160] Therefore, the damping ratio is:

[0161] Damped natural frequency (system natural frequency) f d =f peak ≈6885Hz.

[0162] Undamped natural frequency

[0163] Attenuation coefficient σ=ζω n =2πf n ζ≈173rad / s.

[0164] pole

[0165] (6) The test calculation results are compared with the whole machine modal simulation results as shown in Table 2:

[0166]

[0167] The comparison results show that the calculation method has small errors when processing high-frequency modal analysis, with the error between the calculation results and the simulation results being within 3%, demonstrating high accuracy. Furthermore, it is easy to implement in engineering applications, has low dependence on equipment hardware, and has extremely high engineering application value.

[0168] This embodiment also provides a test estimation device for key high-order modes of a permanent magnet motor stator. This device is used to implement the above embodiments and preferred embodiments, and will not be repeated as already described. As used below, the term "module" can be a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0169] This embodiment provides an experimental estimation device for key high-order modes of a permanent magnet motor stator, such as... Figure 7 As shown, it includes:

[0170] The data acquisition and extraction module 701 is used to adjust the carrier frequency of the frequency converter within a preset frequency range and calculate the current amplitude and noise amplitude of the permanent magnet motor under multiple preset carrier frequencies.

[0171] The parameter calculation module 702 is used to construct a mathematical model of the frequency response function and calculate the parameter values ​​of the mathematical model of the frequency response function at each preset carrier frequency based on the current amplitude and noise amplitude at each preset carrier frequency.

[0172] The higher-order modal parameter determination unit 703 is used to plot the modal frequency response curve corresponding to the higher-order mode based on the parameter values ​​of the frequency response function mathematical model, and to determine the modal parameters corresponding to the higher-order mode based on the modal frequency response curve.

[0173] In some optional implementations, the data acquisition and extraction module 701 includes:

[0174] The signal acquisition unit is used to adjust the carrier frequency of the frequency converter within a preset frequency range and acquire current signals and noise signals.

[0175] The time-frequency conversion unit is used to perform Fourier transforms on the current signal and the noise signal respectively to obtain the current spectrum and the noise spectrum.

[0176] The amplitude determination unit is used to determine the current amplitude corresponding to each preset carrier frequency based on the current spectrum, and to determine the noise amplitude corresponding to each preset carrier frequency based on the noise spectrum.

[0177] In some alternative implementations, the parameter calculation module 702 includes:

[0178] The mapping determination unit is used to derive the spatiotemporal distribution relationship between the sideband radial electromagnetic force and current based on electromagnetic theory, and to determine the mapping relationship between the time order and higher-order vibration modes using the spatiotemporal distribution relationship between the sideband radial electromagnetic force and current.

[0179] The higher-order mode determination unit is used to determine the higher-order mode to which each preset carrier frequency belongs based on the mapping relationship between time order and higher-order mode.

[0180] The parameter value calculation unit is used to calculate the parameter values ​​of the frequency response function mathematical model corresponding to each preset carrier frequency based on the higher-order mode shape to which each preset carrier frequency belongs, and the corresponding current amplitude and noise amplitude, using the corresponding frequency response function mathematical model.

[0181] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0182] In this embodiment, the experimental estimation device for the key high-order modes of the permanent magnet motor stator is presented in the form of a functional unit. Here, a unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0183] This invention also provides a computer device having the above-described features. Figure 7 The experimental estimation device for key high-order modes of permanent magnet motor stator is shown.

[0184] Please see Figure 8 , Figure 8 This is a schematic diagram of the structure of a computer device provided in an optional embodiment of the present invention, such as... Figure 8 As shown, the computer device includes one or more processors 10, memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 8 Take a processor 10 as an example.

[0185] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0186] The memory 20 stores instructions executable by at least one processor 10 to cause the at least one processor 10 to perform the method shown in the above embodiments.

[0187] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0188] The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0189] The computer device also includes a communication interface 30 for communicating with other devices or communication networks.

[0190] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code, which, when accessed and executed by the computer, processor, or hardware, implements the methods shown in the above embodiments.

[0191] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. An experimental estimation method for key high-order modes of a permanent magnet motor stator, characterized in that, Adjusting the carrier frequency of the frequency converter to the initial carrier frequency, so that the permanent magnet motor operates at its rated speed, the method includes: Adjust the carrier frequency of the inverter within a preset frequency range, and calculate the current amplitude and noise amplitude of the permanent magnet motor under multiple preset carrier frequencies; Construct a mathematical model of the frequency response function, and calculate the parameter values ​​of the mathematical model of the frequency response function at each preset carrier frequency based on the current amplitude and noise amplitude at each preset carrier frequency; Based on the parameter values ​​of the frequency response function mathematical model, plot the modal frequency response curves corresponding to the higher-order modes, and determine the modal parameters corresponding to the higher-order modes based on the modal frequency response curves.

2. The method according to claim 1, characterized in that, Adjust the carrier frequency of the frequency converter within a preset frequency range, and calculate the current amplitude and noise amplitude of the permanent magnet motor at multiple preset carrier frequencies, including: Adjust the carrier frequency of the frequency converter within a preset frequency range to obtain current and noise signals; Perform Fourier transforms on the current signal and the noise signal respectively to obtain the current spectrum and the noise spectrum; The current amplitude corresponding to each preset carrier frequency is determined based on the current spectrum, and the noise amplitude corresponding to each preset carrier frequency is determined based on the noise spectrum.

3. The method according to claim 2, characterized in that, The acquisition of current signal and noise signal includes: The current signal is obtained using an ammeter, and the noise signal on the motor surface is obtained using a non-contact noise test sensor.

4. The method according to claim 1, characterized in that, Based on the current amplitude and noise amplitude at each preset carrier frequency, calculate the parameter values ​​of the mathematical model of the frequency response function at each preset carrier frequency, including: The spatiotemporal distribution relationship between sideband radial electromagnetic force and current is derived based on electromagnetic theory, and the mapping relationship between time order and higher-order mode shape is determined using the spatiotemporal distribution relationship between sideband radial electromagnetic force and current. The higher-order vibration mode to which each preset carrier frequency belongs is determined based on the mapping relationship between the time order and the higher-order vibration mode. Based on the higher-order mode shape of each preset carrier frequency, and the corresponding current amplitude and noise amplitude, the parameter values ​​of the corresponding frequency response function mathematical model are calculated using the corresponding frequency response function mathematical model.

5. The method according to claim 4, characterized in that, The mapping relationship between time order and higher-order mode shapes is determined using the spatiotemporal distribution relationship between the sideband radial electromagnetic force and current, including: Based on Maxwell's tensor method, the frequency characteristics of the sideband radial electromagnetic force considering current harmonics are determined. The time order is divided into a first interval corresponding to the 0th order mode shape and a second interval corresponding to the 2p order mode shape, so as to determine the mapping relationship between the time order and the higher order mode shape.

6. The method according to claim 4, characterized in that, Based on the higher-order mode shapes of each preset carrier frequency, and the corresponding current and noise amplitudes, the parameter values ​​of the corresponding frequency response function mathematical model are calculated using the corresponding frequency response function mathematical model, including: The force wave Fourier spectrum corresponding to the higher-order vibration mode is determined based on the calculation formula of the higher-order mode. Based on the residue theorem and the Fourier spectrum of the force wave, the expression of the mathematical model of the frequency response function in the frequency domain is determined. Based on the current amplitude and noise amplitude, the parameter values ​​of the frequency response function mathematical model corresponding to each carrier frequency are calculated using the expression of the frequency response function mathematical model in the frequency domain. The parameter values ​​of the frequency response function mathematical model include: natural frequency and damping ratio.

7. The method according to claim 6, characterized in that, Based on the residue theorem and the Fourier spectrum of the force wave, the expression of the mathematical model of the frequency response function in the frequency domain is determined, including: Based on the vibration theory of single-degree-of-freedom systems, the expression for the system transfer function in the complex frequency domain is: Where H(s) represents the system transfer function, m represents the system mass, c represents the system damping, k represents the system stiffness, s represents the complex frequency domain variables, and p, p * Representing the poles of the system (a pair of conjugate complex numbers), R, R * This represents the residue at the corresponding pole. By replacing the complex frequency domain variables with frequency domain variables and applying the residue theorem, we obtain the expression for the mathematical model of the frequency response function in the frequency domain: Where j represents an imaginary number, and ω represents the vibration frequency of the motor.

8. A test estimation device for key high-order modes of a permanent magnet motor stator, characterized in that, The device for adjusting the carrier frequency of the frequency converter to the initial carrier frequency, enabling the permanent magnet motor to operate at its rated speed, includes: The data acquisition and extraction module is used to adjust the carrier frequency of the frequency converter within a preset frequency range and calculate the current amplitude and noise amplitude of the permanent magnet motor under multiple preset carrier frequencies. The parameter calculation module is used to construct a mathematical model of the frequency response function and calculate the parameter values ​​of the mathematical model of the frequency response function at each preset carrier frequency based on the current amplitude and noise amplitude at each preset carrier frequency. The higher-order modal parameter determination unit is used to plot the modal frequency response curves corresponding to the higher-order modes based on the parameter values ​​of the frequency response function mathematical model, and to determine the modal parameters corresponding to the higher-order modes based on the modal frequency response curves.

9. A computer device, characterized in that, include: A memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, the processor executing the computer instructions to perform the method of any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to perform the method of any one of claims 1 to 7.

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