Electric reactor magnetostriction noise simulation method and system considering pressure stress
By establishing a three-dimensional geometric model and applying compressive stress, the problem of failure to fully consider the impact of compressive stress on the noise characteristics of the reactor in the prior art is solved, and a more accurate magnetostrictive vibration noise simulation is achieved, which is in line with the actual operation of the reactor and provides a theoretical basis for vibration reduction and noise reduction.
Patent Information
- Application Number
- CN202411700083.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-26
- Publication Date
- 2025-04-25
AI Technical Summary
The existing magnetostrictive vibration noise simulation technology of reactors fails to fully consider the impact of compressive stress on noise characteristics, resulting in inaccurate simulation results and difficult to conform to the stress conditions in actual operation of the reactor.
By establishing a three-dimensional geometric model of the dry iron core reactor, adding physics fields and setting boundary conditions, including multi-physical field coupling of circuits, magnetic fields, solid mechanics, pressure acoustic frequency domain field and boundary element acoustic field, compressive stress is applied to simulate the actual operation of the reactor and calculate magnetostrictive vibration and noise characteristics.
The magnetostrictive vibration noise simulation of reactors under different stresses is realized, which improves the accuracy of simulation results and conforms to actual operating conditions, and provides an important theoretical basis for vibration reduction and noise reduction.
Smart Images
Figure CN119885708A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of power equipment state detection, and in particular to a method and system for simulating magnetostrictive noise of a reactor taking compressive stress into consideration. Background Art
[0002] With the continuous increase in the voltage level and scale of transmission lines, dry-type iron core reactors have become important equipment to ensure the stable operation of power systems. The main function is to maintain the voltage stability of the power system, connect in parallel at the end of the line to absorb the inductive reactive power in long-distance transmission lines and substations, and suppress the capacity rise effect. Reactors have serious problems such as high noise and long transmission distance, which affect the service life of the reactor and the health of surrounding residents. The special structure of the reactor core is the main reason for the high noise of the reactor. The core of the reactor is made of silicon steel sheets stacked layer by layer. When the alternating current generates an alternating magnetic field, the magnetic domains inside the silicon steel sheet will move periodically along the direction of the magnetic field under the alternating magnetic field, causing the silicon steel sheet to periodically elongate and shorten, that is, the magnetostrictive effect occurs. Studies have shown that although the magnetostrictive deformation of a single silicon steel sheet is only a few microns per meter, the increase in the core capacity and size leads to a gradual increase in the overall deformation of the core, and the magnetostrictive effect becomes the main cause of the vibration noise of the reactor core. Since the sources of reactor noise include not only magnetostriction but also the influence of the core Maxwell force and the winding Lorentz force, the experiment cannot study the effect of magnetostriction on reactor noise alone. Therefore, it is of great significance to carry out simulation research on the noise characteristics of the reactor core.
[0003] In the actual operation of the reactor, considering the gravity of the reactor itself, as well as the influence of fasteners such as tie rods, clamp bolts, etc., the core silicon steel sheets usually have tensile stress or compressive stress during operation. According to the direction of stress, the stress on the core silicon steel sheets can be divided into compressive stress and tensile stress. According to relevant research, stress will cause the grains inside the core silicon steel sheets to rotate. Among them, when tensile stress acts, the movement of the 180° domain wall in the silicon steel sheet is dominant, which has no positive effect on the deformation of the oriented silicon steel sheet; under the action of compressive stress, the movement of the 90° domain wall dominates the silicon steel sheet, and the 90° domain wall movement will have a positive effect on the deformation of the oriented silicon steel sheet. Therefore, the effect of tensile stress is not obvious, while compressive stress will have a greater impact on the magnetostriction of the silicon steel sheet.
[0004] At present, the simulation technology of magnetostrictive vibration and noise of reactors has been relatively mature, but the influence of compressive stress on magnetostriction in the simulation has not attracted much attention. It is of great significance to study the magnetostrictive and noise characteristics of silicon steel sheets under different amplitude stresses. Therefore, this patent mainly studies the simulation method of magnetostrictive vibration and noise of silicon steel sheets under compressive stress. Summary of the invention
[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a method and system for simulating magnetostrictive noise of a reactor taking into account compressive stress, which has fast calculation speed, high accuracy and is more in line with the stress conditions in actual operation of the reactor.
[0006] The purpose of the present invention can be achieved by the following technical solutions:
[0007] A method for simulating magnetostrictive noise of a reactor considering compressive stress, the method comprising the steps of:
[0008] Establish a three-dimensional geometric model of dry-type iron-core reactor based on its actual size;
[0009] Group and cut the regions of the 3D geometric model, and set the material parameters of each structure after grouping and cutting;
[0010] Add physical fields and set boundary conditions for each physical field, including circuits, magnetic fields, solid mechanics, pressure acoustic frequency domain fields, and boundary element acoustic fields; and perform multi-physical field coupling;
[0011] Apply power frequency current to the three-dimensional geometric model and calculate the distribution and size of the magnetic flux density in the time domain of the reactor under the action of the power frequency current; transform the magnetic field waveform in the time domain into the frequency domain through Fourier analysis to obtain the magnetic field distribution at each frequency;
[0012] Add boundary loads to the three-dimensional geometric model, apply compressive stress to the core of the dry-type iron core reactor in the three-dimensional geometric model, simulate the compressive stress of the reactor during normal operation, and make the core of the reactor produce magnetostrictive vibration;
[0013] The iron core generating magnetostrictive vibration is set as a linear elastic material, and strain and damping are set for the linear elastic material;
[0014] Based on the magnetic-solid coupling of magnetic field-solid mechanics, the vibration magnitude and distribution of the reactor core under the action of power frequency current are calculated, and the calculation results are expressed in the form of vibration acceleration;
[0015] Taking vibration acceleration as the sound source and setting air as the propagation medium, the noise amplitude and distribution of the reactor are calculated by acoustic-solid coupling.
[0016] Furthermore, the calculation of the distribution and size of the magnetic flux density in the reactor time domain is based on Maxwell's equations, which are as follows:
[0017]
[0018] Where: A is the magnetic vector potential Wb / m, σ is the conductivity S / m, t is the time, μ0 is the vacuum permeability, μr is the relative magnetic permeability, J e is the winding current density A / m 2 .
[0019] Further, the Fourier analysis method is:
[0020] Ordinary differential and differential algebraic equations are used to calculate the magnetic field of the reactor, and the magnetic field in the time domain is put into the frequency domain through FFT calculation from time domain to frequency domain.
[0021] Furthermore, the loading method for applying compressive stress on the core of the dry-type iron core reactor in the three-dimensional geometric model is:
[0022] A fixed constraint is applied to the bottom of the three-dimensional model of the reactor, and a boundary load is added to the core of the reactor in the three-dimensional model. The boundary load is the total force F = (F x ,F y ,F z ), the total force makes the reactor core subject to constant stress, sets the magnitude and direction of the constant stress on the reactor core, and sets the constant stress as compressive stress.
[0023] Furthermore, in the process of adding the total force as the boundary load, a plurality of stress conditions with different amplitudes are set for the total force; after the plurality of stress conditions with different amplitudes are set, the amplitude of the magnetostrictive vibration of the reactor under different stresses is simulated and calculated.
[0024] Furthermore, the acoustic-solid coupling adopts pressure acoustic boundary element and combines the acoustic BEM-FEM boundary multi-physics field coupling to divide the grid on the surface of the adjacent three-dimensional modeling domain, and calculates the radiated noise based on the divided grid.
[0025] Furthermore, in the process of establishing the three-dimensional geometric model of the dry-type iron core reactor, the iron core reactor model is simplified, and the iron core laminations are simplified into a plurality of iron core cakes of an integrated structure.
[0026] Furthermore, there are air gaps between the core disks, and the air gaps are distributed marble structures. According to the equivalent cross-sectional area, the air gap structure is simplified into an integrated structure.
[0027] Furthermore, the simulation method is performed based on COMSOL finite element simulation software.
[0028] The present invention also provides a reactor magnetostrictive noise simulation system considering compressive stress, comprising a memory and a processor, the memory storing a computer program, and the processor calling the computer program to execute the steps of the above method.
[0029] Compared with the prior art, the present invention has the following advantages:
[0030] (1) In the simulation, the present invention applies boundary loads to the simulated reactor through the solid mechanics module, simulates the compressive stress of the reactor during normal operation, calculates the amplitude of the magnetostrictive vibration of the reactor under different stresses, and studies the influence of the stress amplitude on the vibration of the reactor, which is more in line with the force conditions in the actual operation of the reactor and makes the simulation results more in line with the actual working conditions of the reactor; at the same time, the pressure acoustic boundary element is adopted, and combined with the acoustic BEM-FEM boundary multi-physics field coupling, there is no need to calculate a large volume domain, and only the surface of the adjacent modeling domain needs to be meshed, which is conducive to model convergence.
[0031] (2) The present invention uses ordinary differentials and differential algebraic equations to calculate the magnetic field of the reactor. By converting the time domain into the frequency domain through Fourier analysis, the noise components of different frequencies of the reactor can be calculated, while the calculation speed is accelerated.
[0032] (3) In the process of establishing the three-dimensional geometric model, the present invention simplifies the iron core reactor model by simplifying the air gaps between the core laminations and the core cakes into an integrated structure, thereby simplifying the calculation process and improving the simulation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 This is a flow chart of the simulation method of magnetostrictive noise of a reactor considering compressive stress;
[0034] Figure 2 This is the noise distribution diagram of the reactor. DETAILED DESCRIPTION
[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.
[0036] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0037] Example 1
[0038] like Figure 1As shown, the present embodiment proposes a method for simulating magnetostrictive noise of a reactor considering compressive stress, based on COMSOL finite element simulation software, and mainly studies the method for simulating magnetostrictive vibration noise of silicon steel sheets under compressive stress, including the steps for setting the physical field module of the reactor vibration noise simulation in COMSOL software, and how to calculate the magnetostrictive vibration noise of the reactor under compressive stress. The steps of the method include:
[0039] S1. Use the geometry module to establish a three-dimensional geometric model of the dry-type iron core reactor based on the actual size; simplify the iron core reactor model. Since the core laminations are tightly stacked, the core cake can be simplified into an integrated structure. Each core cake is separated by an air gap of a distributed marble structure. Then, based on the equivalent cross-sectional area, the air gap structure is simplified into an integrated structure.
[0040] S2. Group and cut the reactor regions, and set the material parameters of each structure of the model in the material module.
[0041] S3, and add multiple physical fields such as magnetic field, solid mechanics, pressure acoustic frequency domain field, boundary element, etc., and set the boundary conditions of each physical field to make it conform to the actual operation.
[0042] S4. Set up multi-physics field coupling of magnetic field, solid mechanics, frequency domain acoustic field, boundary element acoustic field, magnetostrictive vibration noise.
[0043] S5. Calculate the distribution and size of the magnetic flux density in the time domain of the reactor under the action of the power frequency current through the circuit and magnetic field module.
[0044] The magnetic field module is based on Maxwell's equations:
[0045]
[0046] Where: A is the magnetic vector potential (Wb / m), σ is the conductivity (S / m), t is the time, μ0 is the vacuum permeability, μ r is the relative magnetic permeability, J e is the winding current density (A / m 2 ).
[0047] S6. Calculate the magnetic field of the reactor using ordinary differential and differential algebraic equations, convert it through the time domain to frequency domain FFT calculation step, and transform the waveform in the time domain into the frequency domain through Fourier analysis.
[0048] In this embodiment, the time domain is converted into the frequency domain so that the noise components of different frequencies of the reactor can be calculated, while increasing the calculation speed.
[0049] Specifically, the Fourier analysis in the steps is as follows:
[0050] Ordinary differential and differential algebraic equations are used to calculate the magnetic field of the reactor, and the magnetic field in the time domain is put into the frequency domain through the time domain to frequency domain FFT calculation step.
[0051] S7. Add boundary loads in the solid mechanics module and apply compressive stress on the core to simulate the compressive stress of the reactor during normal operation. First, add fixed constraints to the bottom of the reactor, add boundary loads to the core, select the total force option, and use F=(F x ,F y ,F z ), set the magnitude and direction of the constant stress on the reactor core and set it as compressive stress.
[0052] During the simulation of this embodiment, the total force option in the boundary load is used to set stress conditions of different amplitudes, namely: F = 0N, -100N and -200N, all of which are compressive stresses. The amplitude of the magnetostrictive vibration of the reactor under different stresses is simulated and calculated to study the influence of the stress amplitude on the vibration of the reactor.
[0053] S8. Setting a linear elastic material for magnetostrictive vibration, and setting strain and damping in the linear elastic material.
[0054] S9. Based on the magnetic-solid coupling of magnetic field-solid mechanics, calculate the vibration size and distribution of the reactor core under the action of power frequency current;
[0055] S10. Taking vibration acceleration as the sound source and air as the propagation medium, pressure acoustic boundary element is used, and combined with acoustic BEM-FEM boundary multi-physics field coupling, the radiated noise amplitude is calculated by acoustic-solid coupling. At this time, there is no need to calculate large volume domains, and only the surface of the adjacent modeling domain needs to be meshed, which is beneficial to the convergence of the model and the computational efficiency.
[0056] The noise sound pressure level of the reactor under stress conditions of different amplitudes is shown in the following table.
[0057] Total force F / N 0N -100N -200N Noise sound pressure level / dB(A) 45.5 63.8 71.9
[0058] It can be found that with the increase of compressive stress, the magnetostrictive noise of the reactor gradually increases. When F = -200N, the core noise of the reactor reaches nearly 71.9dB(A), compared with only 45.5dB(A) when F = 0N.
[0059] When the frequency is 100Hz, the noise distribution of the reactor is as follows: Figure 2As shown. Under the action of compressive stress, the movement of the 90° domain wall of the silicon steel sheet in the reactor core is dominant, which has a great influence on the deformation of the oriented silicon steel sheet. Considering the compressive stress can better meet the actual stress conditions of the reactor in operation. This method introduces compressive stress of different amplitudes in the simulation to study the noise characteristics of the reactor under compressive stress, which can provide an important theoretical basis for vibration reduction and noise reduction.
[0060] Example 2
[0061] This embodiment provides a system for simulating magnetostrictive noise of a reactor considering compressive stress, including a memory and a processor, wherein the memory stores a computer program, and the processor calls the computer program to execute the steps of the method for simulating magnetostrictive noise of a reactor considering compressive stress as described in Embodiment 1.
[0062] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.
Claims
1. A method for simulating magnetostrictive noise of a reactor considering compressive stress, characterized in that: The following steps are involved: Establish a three-dimensional geometric model of dry-type iron-core reactor based on its actual size; Group and cut the regions of the 3D geometric model, and set the material parameters of each structure after grouping and cutting; Add physical fields and set boundary conditions for each physical field, including physical fields of circuits, magnetic fields, solid mechanics, pressure acoustic frequency domain fields, and boundary element acoustic fields; and perform multi-physical field coupling; Apply power frequency current to the three-dimensional geometric model and calculate the distribution and size of the magnetic flux density in the time domain of the reactor under the action of the power frequency current; transform the magnetic field waveform in the time domain into the frequency domain through Fourier analysis to obtain the magnetic field distribution at each frequency; Add boundary loads to the three-dimensional geometric model, apply compressive stress to the core of the dry-type iron core reactor in the three-dimensional geometric model, simulate the compressive stress of the reactor during normal operation, and make the core of the reactor produce magnetostrictive vibration; The iron core generating magnetostrictive vibration is set as a linear elastic material, and strain and damping are set for the linear elastic material; Based on the magnetic-solid coupling of magnetic field-solid mechanics, the vibration magnitude and distribution of the reactor core under the action of power frequency current are calculated, and the calculation results are expressed in the form of vibration acceleration; Taking vibration acceleration as the sound source and setting air as the propagation medium, the noise amplitude and distribution of the reactor are calculated by acoustic-solid coupling.
2. The method for simulating magnetostrictive noise of a reactor considering compressive stress according to claim 1, characterized in that: The calculation of the distribution and size of the magnetic flux density of the reactor in the time domain is based on Maxwell's equations, and the formula of Maxwell's equations is: Where: A is the magnetic vector potential Wb / m, σ is the conductivity S / m, t is the time, μ0 is the vacuum permeability, μ r is the relative magnetic permeability, J e is the winding current density A / m 2 .
3. The method for simulating magnetostrictive noise of a reactor considering compressive stress according to claim 1, characterized in that: The Fourier analysis method is: Ordinary differential and differential algebraic equations are used to calculate the magnetic field of the reactor, and the magnetic field in the time domain is put into the frequency domain through FFT calculation from time domain to frequency domain.
4. The method for simulating magnetostrictive noise of a reactor considering compressive stress according to claim 1, characterized in that: The loading method for applying compressive stress on the iron core of the dry-type iron core reactor in the three-dimensional geometric model is: A fixed constraint is added to the bottom of the three-dimensional model of the reactor, and a boundary load is added to the reactor core of the three-dimensional model. The boundary load is the total force F = (F x ,F y ,F z ), where F x 、F y and F z are the components of the total force F on the x-axis, y-axis and z-axis respectively. The total force causes the reactor core to be subjected to a constant stress. The magnitude and direction of the constant stress on the reactor core are set, and the constant stress is set as a compressive stress.
5. The method for simulating magnetostrictive noise of a reactor considering compressive stress according to claim 4, characterized in that: In the process of adding the total force as the boundary load, a plurality of stress conditions with different amplitudes are set for the total force; after the plurality of stress conditions with different amplitudes are set, the amplitude of the magnetostrictive vibration of the reactor under different stresses is simulated and calculated.
6. The method for simulating magnetostrictive noise of a reactor considering compressive stress according to claim 1, characterized in that: The acoustic-solid coupling adopts pressure acoustic boundary element and combines acoustic BEM-FEM boundary multi-physics field coupling to divide grids on the surface of the modeling domain adjacent to the three-dimensional model, and calculates the radiated noise based on the divided grids.
7. The method for simulating magnetostrictive noise of a reactor considering compressive stress according to claim 1, characterized in that: In the process of establishing the three-dimensional geometric model of the dry-type iron core reactor, the iron core reactor model is simplified, and the iron core laminations are simplified into a plurality of iron core cakes of an integrated structure.
8. The method for simulating magnetostrictive noise of a reactor considering compressive stress according to claim 7, characterized in that: The core cakes are separated by air gaps, and the air gaps are distributed marble structures. The air gap structure is simplified into an integrated structure according to the equivalent cross-sectional area.
9. The method for simulating magnetostrictive noise of a reactor considering compressive stress according to claim 1, characterized in that: The simulation method is performed based on COMSOL finite element simulation software.
10. A reactor magnetostrictive noise simulation system considering compressive stress, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and the processor calls the computer program to execute the steps of any one of the methods according to claims 1 to 9.