CN114580235A - Design method of vibration scaling model of converter transformer - Google Patents
Design method of vibration scaling model of converter transformer Download PDFInfo
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Abstract
The invention provides a design method of a vibration scaling model of a converter transformer, which comprises the following steps: obtaining the frequency, current, voltage, resistance and magnetic flux density of a scaling model based on an electromagnetic field parameter scaling criterion; acquiring magnetostrictive force, Lorentz force, iron core acceleration and winding acceleration of a scaling model based on a vibration parameter scaling criterion; and constructing a converter transformer multi-physical field coupling three-dimensional model based on a finite element simulation platform, and performing similar treatment on corresponding parameters of the converter transformer multi-physical field coupling three-dimensional model according to an electromagnetic field parameter scaling criterion and a vibration parameter scaling criterion to obtain a scaling model. Through comparative analysis of magnetic flux density distribution, stress distribution, deformation quantity and vibration time domain and frequency domain signals, the model of the converter transformer is proved to correspond to the similarity criterion in the aspects of electromagnetic field and structure mechanics before and after the model is similar, and therefore the correctness of the converter transformer scaling model is verified comprehensively.
Description
Technical Field
The invention belongs to the technical field of converter transformers, and particularly relates to a design method of a converter transformer vibration scaling model.
Background
The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.
The converter transformer is one of core devices of a high-voltage direct-current transmission system, compared with a common transformer, the converter transformer bears the combined action of alternating-current and direct-current voltages during operation, and load current of the converter transformer contains a large amount of direct-current magnetic biasing current and higher harmonics, so that the electromagnetic force borne by the converter transformer and the resonance effect of an iron core are more obvious, and the iron core and a winding are very complicated in vibration due to the inherent magnetostriction effect of an iron core material under an alternating magnetic field. The vibration of the iron core and the winding can be transmitted to the surface of the oil tank through the box body structure, and more complex vibration and noise of the whole converter transformer are caused, so that the safe operation of the converter transformer is threatened. People are dedicated to the research on the vibration generation mechanism and vibration suppression of the converter transformer, and are still puzzled by the changeable test environment, the numerous electromagnetic field distribution and the complex vibration propagation process of the converter transformer, the main factors of the noise generation mechanism are still controversial so far, and the vibration suppression effect is also difficult to meet the requirement of the development of the high-voltage direct-current transmission technology.
According to a similar principle, the converter transformer is reduced to the amount which can be accommodated in a laboratory in an equal proportion so as to meet ideal test conditions, and the method is an effective measure for solving the problem of complex test environment of the high-capacity converter transformer.
However, in the current numerous researches, a unified similar method aiming at the vibration suppression research of the converter transformer does not exist, and an effective method for verifying the accuracy of the similarity criterion of the converter transformer is lacked, so that the reliability of the scaling model of the converter transformer is greatly reduced. In related research, consistency of an electromagnetic field and a vibration frequency spectrum is mostly used as a detection method for accuracy of a scaling model, but the premise is that the model is subjected to analysis of the electromagnetic field and the vibration signal after being prepared, and model verification is meaningless. Meanwhile, due to the limitation of detection technology, stress analysis of the internal elements of the scale model is difficult to perform, so that the means for verifying the vibration characteristics of the scale model is limited to the vibration signal analysis of the external points of the model. The finite element simulation technology provides an idea for analyzing the multi-field coupling device with a complex internal structure. However, in the current finite element model research, electromagnetic field analysis is also used as a verification method of a scaling model, and the consistency of similar front and back vibration characteristics is not used as a core thought of the converter transformer vibration model verification. The existing scaling model has no unified scaling rule aiming at the vibration research of the converter transformer; and a prior method of a more comprehensive current conversion transformer vibration scaling model is lacked. If the accuracy of the scaling criterion can be determined before the scaling model is manufactured, the efficiency and the reliability of the experiment can be greatly improved.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a design method of a vibration scaling model of a converter transformer, which is used for deducing a similarity criterion suitable for the vibration characteristic research of the converter transformer and constructing the converter transformer model and the scaling model thereof on the basis of ensuring that the response relation between the input and the vibration of the converter transformer is not changed before and after the similarity.
In order to achieve the above object, one or more embodiments of the present invention provide the following technical solutions:
in a first aspect, a method for designing a vibration scaling model of a converter transformer is disclosed, which includes:
obtaining the frequency, current, voltage, resistance and magnetic flux density of a scaling model based on an electromagnetic field parameter scaling criterion;
acquiring magnetostrictive force, Lorentz force, iron core acceleration and winding acceleration of a scaling model based on a vibration parameter scaling criterion;
and constructing a converter transformer multi-physical field coupling three-dimensional model based on a finite element simulation platform, and performing similar treatment on corresponding parameters of the converter transformer multi-physical field coupling three-dimensional model according to an electromagnetic field parameter scaling criterion and a vibration parameter scaling criterion to obtain a scaling model.
In a further technical scheme, the electromagnetic field parameter scaling criterion specifically comprises:
TABLE 1 electromagnetic field parameter scaling criterion
k is a scale factor of the similarity criterion.
In a further technical scheme, the vibration parameter scaling criterion specifically comprises:
TABLE 2 vibration parameter scaling criterion
k is a scale factor of the similarity criterion.
According to the further technical scheme, the electromagnetic field parameter scaling criterion and the vibration parameter scaling criterion select magnetic flux density as a reference value, a scaling factor of a similar criterion is introduced, and the number of turns of a coil is kept unchanged before and after scaling.
In a further technical scheme, the magnetic permeability, the dielectric constant, the electric conductivity, the magnetic permeability and the electric resistivity of the iron core and the winding material of the scaling model are consistent with those of the original model.
According to the further technical scheme, in the process of constructing the multi-physical-field coupling three-dimensional model of the converter transformer, the structure of the converter transformer is subjected to idealized processing, a clamp structure is ignored, and corresponding fixed constraints are applied to a winding and an iron core to serve as boundary conditions;
coupling the magnetic field model with an external circuit by applying a field-circuit coupling method, and respectively endowing corresponding material attributes to the iron core, the winding and other domains;
lorentz force is applied to the windings as a body load, a magnetostrictive module is added to the iron core region, voltage source excitation is added to each winding, and input and output ports of the windings are arranged.
According to the further technical scheme, when the magnetic flux density distribution of the scaling model is analyzed, the longitudinal section of the iron core is subjected to three-dimensional symmetry, so that a magnetic flux density module value distribution map of the surface of the iron core is obtained, the magnetic flux density values with different intensities at all positions of the surface of the iron core are distinguished by different colors in the distribution map, and arrows represent the direction and the path of magnetic flux.
In a second aspect, a design system of a vibration scaling model of a converter transformer is disclosed, which includes: a server configured to perform the following:
obtaining the frequency, current, voltage, resistance and magnetic flux density of a scaling model based on an electromagnetic field parameter scaling criterion;
acquiring magnetostrictive force, Lorentz force, iron core acceleration and winding acceleration of a scaling model based on a vibration parameter scaling criterion;
and constructing a converter transformer multi-physical field coupling three-dimensional model based on a finite element simulation platform, and performing similar treatment on corresponding parameters of the converter transformer multi-physical field coupling three-dimensional model according to an electromagnetic field parameter scaling criterion and a vibration parameter scaling criterion to obtain a scaling model.
The above one or more technical solutions have the following beneficial effects:
the invention analyzes the magnetic flux density distribution, stress distribution, deformation and vibration characteristics of the model before and after the similarity, and verifies the correctness of the similarity criterion.
According to the invention, through comparative analysis of magnetic flux density distribution, stress distribution, deformation quantity, vibration time domain and frequency domain signals, the model of the converter transformer is proved to correspond to the similarity criterion in the aspects of electromagnetic field and structure mechanics before and after the model is similar, so that the correctness of the converter transformer scaling model is comprehensively verified. The comparison result shows that the main vibration of the converter transformer scaling model is still the magnetostrictive effect of the iron core under the magnetic field, the main frequency of the vibration signal is even times of the excitation source, and the above characteristics are not changed in the scaling process. The vibration scaling model of the converter transformer and the verification method thereof have certain reference values for the vibration characteristics and the inhibition research of the converter transformer and the improvement of the operation reliability of the converter transformer.
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.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.
FIG. 1 is a simplified model of an embodiment of the present invention;
FIG. 2 is a magnetic flux density distribution diagram;
FIG. 3 is a graph of core stress distribution;
FIG. 4 is a winding stress distribution diagram;
FIG. 5 is an overall stress profile;
FIG. 6 winding displacement diagram;
FIG. 7 is a graph of core displacement;
FIG. 8 is a similar graph of front and rear Point 1 vibration signals;
fig. 9 is a similar graph of the front and rear dot 2 vibration signals.
Detailed Description
It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, 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 belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention.
The embodiments and features of the embodiments of the present invention may be combined with each other without conflict.
Example one
The embodiment discloses a design method of a vibration scaling model of a converter transformer, which comprises the following steps:
obtaining the frequency, current, voltage, resistance and magnetic flux density of a scaling model based on an electromagnetic field parameter scaling rule;
acquiring magnetostrictive force, Lorentz force, iron core acceleration and winding acceleration of a scaling model based on a vibration parameter scaling criterion;
and constructing a converter transformer multi-physical field coupling three-dimensional model based on a finite element simulation platform, and performing similar treatment on corresponding parameters of the converter transformer multi-physical field coupling three-dimensional model according to an electromagnetic field parameter scaling criterion and a vibration parameter scaling criterion to obtain a scaling model.
With respect to the electromagnetic field parameter scaling criterion: according to the similarity theory, the similarity criterion can be derived through differential equations describing the same physical process without solving equations. In order to better restore the vibration characteristics of the converter transformer, the selection of the reference value of the similarity criterion should be considered more fully. The magnetic flux density of the iron core is one of the main considered indexes in the design of the converter transformer, the magnitude of the magnetic flux density influences the working characteristics and the vibration characteristics of the iron core, and the magnetic flux density is selected in the linear region of a B-H curve. The core material generally operates at a flux density of 1.5-1.8T based on the operating characteristics of the converter transformer. In order to ensure the normal working performance of the iron core and reduce the vibration characteristic of the iron core, the magnetic flux density B is selected as a reference value according to the similarity criterion of the invention. Introducing a scaling factor k with a similarity criterion, the length l, the width w and the height h of the converter transformer are respectively reduced to l '═ kl, w' ═ kw and h '═ kh, and the area S is reduced to S' ═ k2And S. The number of turns N of the coil should be kept constant before and after the scaling, and the number of turns N of the coil per unit length after the scaling is N' ═ k-1n is the same as the formula (I). The frequency is inversely proportional to the square of the skin depth, and the skin depth δ is reduced to δ '═ k δ, so the frequency of the scaled converter transformer is f' ═ k-2f。
The converter transformer can be described in the electromagnetic field state of the normal working state by adopting the following equation:
J＝σE (5)
B＝μH (6)
where B is magnetic induction intensity, H is magnetic field intensity, E is electric field intensity, D is electric displacement vector, J is current density, σ is electric conductivity, μ is magnetic conductivity, ε is dielectric constant, ρ is charge density, and S is area.
Based on Maxwell's equation and similar theory, the integral form according to Ampere's law ═ μ Bdl ═ μ, assuming that the magnetic field density B remains constant0NI is known as I' ═ kI. According to the scaling rule of l and S, the scaled resistance R' is k-1R and rho are resistivity. Because U ═ IR, the voltage is reduced to U' ═ U according to the scaling criterion of I and R. According to G ═ I/U, scaled conductance G ═ kG is obtained. From G/σ ═ C/epsilon, C' ═ kC is obtained. According to the scaling rule of L ═ U/2 pi fI, and U, I and f, the inductance is reduced to L' ═ kL. Similar criteria for the main electromagnetic field parameters are listed in table 1. And determining the corresponding relation of the current conversion transformer magnetic field parameters before and after the scaling by using the above criterion.
TABLE 1 electromagnetic field parameter scaling criterion
Vibration parameter scaling criterion:
starting from parameters directly related to the vibration, similar analysis is carried out on the parameters so as to ensure that the vibration characteristics of the model are consistent before and after the similarity. According to previous studies, the vibration of the converter transformer is mainly caused by the core and the winding. Therefore, in order to equalize the vibration intensity and distribution of the core limb and the winding, the mass matrix M and the stiffness coefficient matrix K need to be reduced in equal proportion, and the natural frequency of the structure is obtained
Almost unchanged, and theoretically extends the mode and the mode shape of the converter transformer. IronThe permeability, dielectric constant, conductivity sigma, permeability mu and resistivity rho of the core and winding materials are kept consistent with the original model.
The finite element kinetic equation of the winding and iron core structure is as follows:
wherein
And
the node acceleration vector and the node velocity vector are obtained, M is a mass matrix of the model, C is a damping matrix of the model, K is a rigidity matrix, and Q (t) is a load vector.
The magnetostriction of the magnetic material in the parallel and perpendicular directions is respectively:
εp＝αB2 (8)
εv＝-νεp (9)
where α is the material coefficient and v is the poisson's ratio. According to the relationship between applied voltage and magnetic flux density:
as can be seen, the magnetostrictive force F at the nodecAnd square U of applied voltage2Proportional ratio, and the magnetostriction force on the similar back iron core is F because the voltage before and after the similarity is unchangedc'＝Fc。
The winding is subjected to radial electrodynamic force F generated by axial and radial leakage magnetic fluxes under the condition of an alternating magnetic field generated by alternating currentxAnd axial electromotive force Fz：
Fx＝iBzt·2πr (11)
Fz＝iBxt·2πr (12)
The resultant electromagnetic force F of the twolComprises the following steps:
where r is the winding radius, itIs the winding current, BtI is the effective value of current for the leakage flux density. The stress of the winding, the current i and the density B of the leakage magnetic field can be knowntAnd winding radius r. The stress F of the back winding is similar because i ' is ki, B ' is B, and r ' is krl'＝k2Fl。
Iron core vibration acceleration a caused by magnetostriction under action of voltage ucComprises the following steps:
wherein epsilonsIs the saturation magnetostriction rate of the silicon steel sheet, omega is the angular frequency of a voltage source, BsIs iron core saturation magnetic induction,/1The length of the silicon steel sheet and the area A of the silicon steel sheet. After the model is similar, epsilonsAnd u is unchanged, a ═ k2A，Bs'＝BsSo that the model is similar to the vibration acceleration a of the rear iron corec'＝k-3ac。
Equating the winding vibration as a mass-spring-damper system, Lorentz forces FlThe differential equation of the vibration displacement x of the winding under action is as follows:
wherein m is a mass matrix, s is a stiffness matrix, and c is a damping matrix. Setting the initial state as zero, solving to obtain the vibration acceleration:
wherein
The parameters of the transformer are related to constants under initial conditions. Knowing the vibration acceleration and I of the winding2Proportional, the vibration acceleration of the winding after the model similarity should be al'＝k2al. Vibration parameters before and after the model is similar are listed in a table 2, and the corresponding relation of the vibration parameters of the converter transformer before and after the scaling is determined by utilizing the above criteria.
TABLE 2 vibration parameter scaling criterion
Physical model of converter transformer:
based on a finite element simulation platform, taking a 500kV converter transformer as an example, a converter transformer multi-physical field coupling three-dimensional model is constructed. Considering the symmetrical physical structure of the converter transformer, the model is divided into four completely symmetrical parts, only one part of the four parts is studied to reduce the operation amount, and the effect of the simplified model is shown in fig. 1.
In the modeling process, the structure of the converter transformer is subjected to idealized processing, structures such as clamps are omitted, and corresponding fixed constraints are applied to the winding and the iron core to serve as boundary conditions. And coupling the magnetic field model with an external circuit by applying a field path coupling method. Corresponding material properties are respectively given to the core, the winding and other domains. Lorentz force is applied to the winding as a body load, and a magnetostrictive module is added to the iron core domain. Voltage source excitation is added to each winding and the input and output ports thereof are set. The parameter settings of the model are shown in table 3. In order to obtain a more accurate operation result, the tolerance is set to be 0.1, the grid cell size is set to be ultra-fine, the degree of freedom of solution is increased to 610654, and the solution time is 1928 s. The calculation result comprises magnetic flux density distribution, stress distribution, deformation quantity and acceleration of each part of the converter transformer, so that the vibration mode analysis of the converter transformer is facilitated.
TABLE 3 model parameter configuration
Converter transformer proportional model: according to the analysis of the similarity principle of the converter transformer, corresponding parameters of the physical model of the converter transformer are similarly processed. And selecting a similarity coefficient k to be 0.1, correspondingly, keeping the voltage unchanged after the similarity, increasing the resistance to 10 times, increasing the frequency to 100 times, reducing the current to 0.1 time, increasing the inductance and the capacitance to 10 times, and listing the operation parameters of the physical model of the converter transformer after the similarity in table 4. It should be noted that, after the frequency is increased to 100 times, the time-related operation needs to be corrected, and the output time is set in the transient state research step, so that the time length and the step length of the output are reduced to 100 times at the same time. The grid cell size was also set to be ultra-fine, with a tolerance set to 0.1, a number of solution degrees of freedom 610654, and a solution time 2102 s. The method aims at the research of the converter transformer vibration analysis and suppression expansion scaling model, so that the foothold of the scaling model verification lies in the consistency analysis of the vibration conditions before and after the model is similar. The magnetic flux density distribution, stress distribution and vibration signal of the converter transformer models before and after the similarity are compared and analyzed.
TABLE 4 operating parameters
Results and discussion:
magnetic flux density distribution: the longitudinal section of the iron core is three-dimensionally symmetrical, so that a distribution diagram of the magnetic flux density modulus of the surface of the iron core is obtained, as shown in fig. 2. The different colors distinguish the flux density values of different intensities at various positions on the surface of the iron core, and the arrows represent the directions and paths of the magnetic fluxes. It can be seen from the figure that the magnetic induction intensity distribution, the magnetic flux direction and the magnetic flux path on the main magnetic circuits of the similar front and rear converter transformers are basically consistent, and the strong magnetic flux density points on the iron core are distributed at the corners and junctions of the iron core. The magnetic flux density mode threshold values of the similar front and back models are kept consistent and are all around 1.5T, and the magnetic flux density mode threshold values are kept consistent with the magnetic field similarity conditions in the similarity criterion.
And (3) analyzing the stress of the iron core: and respectively carrying out three-dimensional symmetry on the iron core domain and the winding domain to obtain a whole iron core domain and winding domain model, and obtaining a whole converter transformer domain model by using the same method. Because the frequency is increased to 100 times of the original frequency after the similarity, the model time point after the similarity corresponds to 0.01 time of the time point of the original model according to the relation between the frequency and the time, and the time points of all the time domain graphs are selected according to the time point.
Fig. 3 shows the stress distribution of the converter transformer core, arrows represent the stress directions, and the color depth represents the stress of the core. It is clear from the figure that the stress distributions of the similar front and rear iron cores are basically consistent, which indicates that the stress points and the stress directions of the surfaces of the similar front and rear iron cores are unchanged. The main stressed areas of the similar front and rear iron cores are basically consistent and are positioned in a magnetic flux loop, and four points with most obvious stress are positioned at the corners of the iron cores, which corresponds to the prior magnetic flux density analysis. The stress amplitude of the similar front iron core is 3.54 multiplied by 107Pa, the stress amplitude of the similar rear iron core is 3.98 multiplied by 107Pa, which are both kept identical in magnitude, which corresponds to the input voltage of the converter transformer being unchanged before and after the similarity. The relationship curve of the magnetostrictive length and the magnetic flux density can be approximately expressed as a quadratic relationship according to a formula
It can be known that the magnetostrictive force applied to the iron core is proportional to the square of the voltage, so the stress magnitude and distribution shown in the figure are reasonable.
And (3) analyzing the stress of the winding: fig. 4 shows the stress distribution of the converter transformer winding, and it can be seen that the stress points, stress directions and stress distribution of the front and rear windings are similar and kept consistent. The amplitude of the stress borne by the similar front winding is 237Pa, the amplitude of the stress borne by the similar rear winding is 2.78Pa, and the two show approximate k2This is consistent with the analysis of the electrodynamic force calculation equation 13 on the winding. Due to relative hardness of winding materialsThe stress variation with the current is not only dependent on the electromagnetic force, but also related to the vibration of iron core and other parts and the periodic variation of electric field, and the variation of the stress variation with the value before and after the similarity has a certain error with the expected proportional relation, but the magnitude of the stress variation keeps the corresponding relation.
Analyzing the integral stress of the model: fig. 5 shows the overall stress condition of the converter transformer, and it can be seen from the figure that the stress points, stress directions and surface stress distributions of the front and rear surfaces are similar to each other. It can be seen that the amplitude of the stress applied to the whole converter transformer is very close to that of the iron core, the stress applied to the winding is not obvious in the whole stress distribution, and the difference of the stress applied to the winding and the stress on the iron core is larger in magnitude compared with the stress on the iron core. As analyzed previously, the converter transformer bulk vibration is dominated by core stress, i.e. the dominant factor affecting converter transformer vibration is the magnetostrictive effect of the core.
And (3) deformation analysis of the winding and the iron core: as shown in FIG. 6, the deformation positions, deformation trends and deformation distributions of the similar front and rear windings are kept consistent, and the deformation magnitude of the similar front winding is 8.19 × 10-10m, the amplitude of the deformation of the similar back winding is 9.16 multiplied by 10-12m, differing by about k2And (4) multiplying. The deformation of the winding mainly comes from the electromagnetic force generated by current and leakage flux, and the change rule of the winding is kept consistent with the similar process of the current on the whole.
Fig. 7 represents the deformation of the iron core of the converter transformer, the deformation positions, deformation trends and deformation amount distributions of the iron cores before and after the similarity are kept consistent, and the deformation amount thresholds before and after the similarity are kept consistent in magnitude. With the continuous progress of the production process of the transformer, the gaps between the silicon steel sheets of the iron core become smaller, and the electromagnetic force between the laminated sheets can be not considered, so that the deformation of the iron core mainly comes from the magnetostriction effect under a magnetic field, which is in direct proportion to the square of voltage. In conclusion, displacement rules before and after the converter transformer vibration scaling model is similar are verified.
Analyzing a vibration signal: to more accurately verify the model correctness, a point is taken on the surface of the core and the winding, respectively named as point 1 and point 2, and the vibration signals are extracted from the points, as shown in fig. 8.
In fig. 8, (a) and (d) show the vibration acceleration frequency spectra at the similar fore-and-aft points 1, respectively, and it can be seen that the maximum peaks of the similar fore-and-aft vibration acceleration are distributed at 100Hz and 10000Hz, respectively, which correspond to the double relation with the frequency value of the respective excitation source. Except that the maximum peak value of the vibration acceleration of the similar rear iron core is 228.39m/s2Is the maximum peak value of the vibration acceleration before the similarity is 0.19m/s2K of (a)-3This is consistent with the analysis of equation 14. In fig. 8, (b) and (e) correspond to the stress-time curves at similar front and rear points 1, respectively, and the waveforms of both are almost identical, and the peaks of the curves are kept identical in magnitude. In fig. 8, (c) and (f) represent the magnetostrictive contribution at point 1 before and after the similarity, respectively, and it can be seen that the magnetostrictive force-time waveforms at the point before and after the similarity are consistent, and the peak values of the two have the same difference k2And (4) doubling. It should be noted that the magnetostrictive contribution at the point 1 is close to the stress value at the point before and after the similarity, that is, the stress applied to the iron core depends on the magnetostrictive effect under the magnetic field before and after the similarity of the model.
Fig. 9 shows a diagram of the vibration signal analysis at the winding signal extraction point 2. In FIG. 9, (a) and (d) are the vibration acceleration frequency spectrum diagrams at the similar front and rear points 2, respectively, the maximum peaks of the similar front and rear vibration acceleration are also distributed at 100Hz and 10000Hz, respectively, and the deformation magnitude of the similar front winding is 3.51 × 10-2m, the amplitude of the deformation of the similar back winding is 3.5 multiplied by 10- 4m, vibration amplitude difference of about k2This is consistent with the analysis of equation 16. In fig. 9, (b) and (e) correspond to the stress variation curves at the similar front and rear points 2, respectively, the waveforms of the two are almost identical, and the peak values are different by about k2And (4) doubling. In fig. 9, (c) and (f) respectively represent the lorentz force contributions of point 2 before and after the similarity, the waveforms of the two are almost consistent, and the peak value is different by k2This is consistent with the stress distribution of the windings.
And (3) restoring a vibration signal:
as analyzed above, the magnetic flux density amplitude of the model before and after the similarity is kept unchanged, the overall stress of the iron core and the converter transformer is kept unchanged, and the stress phase difference k of the windings is2Double, iron coreVibration acceleration phase difference k-3Time difference k between vibration accelerations of windings2And (4) doubling. When a scaling model prototype is established according to the scaling model and vibration analysis is carried out on the scaling model prototype, the signal measured by the scaling model prototype is multiplied by the corresponding coefficient, so that the signal value of the actual converter transformer can be restored, and the principle that the response relation between the converter transformer input and the vibration is unchanged before and after the similarity is ensured.
Example two
It is an object of this embodiment to provide a computing device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the steps of the above method when executing the program.
EXAMPLE III
An object of the present embodiment is to provide a computer-readable storage medium.
A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the above-mentioned method.
Example four
The present embodiment aims to provide a design system for a vibration scaling model of a converter transformer, which is characterized by comprising: a server configured to perform the following:
obtaining the frequency, current, voltage, resistance and magnetic flux density of a scaling model based on an electromagnetic field parameter scaling criterion;
acquiring magnetostrictive force, Lorentz force, iron core acceleration and winding acceleration of a scaling model based on a vibration parameter scaling criterion;
and constructing a converter transformer multi-physical field coupling three-dimensional model based on a finite element simulation platform, and performing similar treatment on corresponding parameters of the converter transformer multi-physical field coupling three-dimensional model according to an electromagnetic field parameter scaling criterion and a vibration parameter scaling criterion to obtain a scaling model.
The steps involved in the apparatuses of the above second, third and fourth embodiments correspond to the first embodiment of the method, and the detailed description thereof can be found in the relevant description of the first embodiment. The term "computer-readable storage medium" should be taken to include a single medium or multiple media containing one or more sets of instructions; it should also be understood to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by a processor and that cause the processor to perform any of the methods of the present invention.
Those skilled in the art will appreciate that the modules or steps of the present invention described above can be implemented using general purpose computer means, or alternatively, they can be implemented using program code that is executable by computing means, such that they are stored in memory means for execution by the computing means, or they are separately fabricated into individual integrated circuit modules, or multiple modules or steps of them are fabricated into a single integrated circuit module. The present invention is not limited to any specific combination of hardware and software.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.
Claims (10)
1. A design method of a vibration scaling model of a converter transformer is characterized by comprising the following steps:
obtaining the frequency, current, voltage, resistance and magnetic flux density of a scaling model based on an electromagnetic field parameter scaling criterion;
acquiring magnetostrictive force, Lorentz force, iron core acceleration and winding acceleration of a scaling model based on a vibration parameter scaling criterion;
and constructing a converter transformer multi-physical field coupling three-dimensional model based on a finite element simulation platform, and performing similar treatment on corresponding parameters of the converter transformer multi-physical field coupling three-dimensional model according to an electromagnetic field parameter scaling criterion and a vibration parameter scaling criterion to obtain a scaling model.
2. The method for designing a vibration scaling model of a converter transformer according to claim 1, wherein the electromagnetic field parameter scaling criterion is specifically as follows:
TABLE 1 electromagnetic field parameter scaling criterion
k is a scale factor of the similarity criterion.
3. The method for designing a vibration scaling model of a converter transformer according to claim 1, wherein the vibration parameter scaling criterion is specifically as follows:
TABLE 2 vibration parameter scaling criterion
k is a scale factor of the similarity criterion.
4. The method as claimed in claim 1, wherein the electromagnetic field parameter scaling criterion and the vibration parameter scaling criterion are based on magnetic flux density, and a scaling factor of a similarity criterion is introduced, and the number of turns of the coil is kept constant before and after scaling.
5. The method as claimed in claim 1, wherein the permeability, dielectric constant, conductivity, permeability and resistivity of said scaled model core and winding material are consistent with those of the original model.
6. The design method of the vibration scaling model of the converter transformer according to claim 1, wherein in the process of constructing the multi-physical-field coupling three-dimensional model of the converter transformer, the structure of the converter transformer is idealized, the structure of the fixture is omitted, and corresponding fixed constraints are applied to the winding and the iron core as boundary conditions;
coupling the magnetic field model with an external circuit by applying a field-circuit coupling method, and respectively endowing corresponding material attributes to the iron core, the winding and other domains;
lorentz force is applied to the windings as a body load, a magnetostrictive module is added to the iron core region, voltage source excitation is added to each winding, and input and output ports of the windings are arranged.
7. The method as claimed in claim 1, wherein the magnetic flux density distribution of the scale model is analyzed by three-dimensionally symmetrical about the longitudinal section of the core, thereby obtaining a distribution map of magnetic flux density module values on the surface of the core, wherein different colors in the distribution map distinguish the magnetic flux density values of different intensities on various positions on the surface of the core, and the arrows represent the directions and paths of the magnetic fluxes.
8. A design system of a vibration scaling model of a converter transformer is characterized by comprising the following components: a server configured to perform the following:
obtaining the frequency, current, voltage, resistance and magnetic flux density of a scaling model based on an electromagnetic field parameter scaling criterion;
acquiring magnetostrictive force, Lorentz force, iron core acceleration and winding acceleration of a scaling model based on a vibration parameter scaling criterion;
and constructing a converter transformer multi-physical field coupling three-dimensional model based on a finite element simulation platform, and performing similar treatment on corresponding parameters of the converter transformer multi-physical field coupling three-dimensional model according to an electromagnetic field parameter scaling criterion and a vibration parameter scaling criterion to obtain a scaling model.
9. A computing device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor when executing the program performs the steps of the method of any one of claims 1 to 7.
10. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, is adapted to carry out the steps of the method according to any one of the preceding claims 1 to 7.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114925579A (en) * | 2022-06-13 | 2022-08-19 | 山东大学 | Current conversion transformer vibration scaling model design method based on current density invariance |
| CN117540539A (en) * | 2023-10-25 | 2024-02-09 | 湖南大学 | Transformer optimal design method and system based on vibration acceleration |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114925579A (en) * | 2022-06-13 | 2022-08-19 | 山东大学 | Current conversion transformer vibration scaling model design method based on current density invariance |
| CN114925579B (en) * | 2022-06-13 | 2024-08-06 | 山东大学 | Current density-invariant-based converter transformer vibration scaling model design method |
| CN117540539A (en) * | 2023-10-25 | 2024-02-09 | 湖南大学 | Transformer optimal design method and system based on vibration acceleration |
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