Finite Element Calculation Method, Device and Terminal for Excitation Characteristics of Transformer Core

Abstract

The present invention provides a finite element calculation method, device and terminal for the excitation characteristics of a transformer core. The method includes: establishing a structural model of the transformer, performing mesh division on the structural model of the transformer to obtain a three-dimensional finite element magnetic field model; based on the three-dimensional finite element magnetic field, obtaining the transient current value and dynamic inductance value of the transformer winding through circuit calculation, obtaining the excitation current value and magnetic flux density distribution of the transformer core through magnetic field calculation. Through the structural model and finite element calculation method provided by the present invention, the excitation characteristic changes of the transformer core under different excitation conditions can be reflected time-saving and efficiently.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and in particular, to a finite element calculation method, device, and terminal for the excitation characteristics of a transformer core. Background Art

[0002] With the continuous growth and development of China's power grid, more and more distributed power sources of new energy power generation forms such as wind energy and solar energy are connected to the grid for operation. A large number of power electronic devices are put into application. For example, high-power rectifier devices, frequency converters, industrial arc furnace loads, etc. The large-scale application of these power electronic devices will bring serious inter-harmonic power pollution, resulting in an increasingly complex waveform of the power system.

[0003] As an important device in the power system, the transformer with an iron core winding will have distorted winding current under the influence of inter-harmonic voltage, resulting in the iron core reaching an oversaturated state, thus causing distorted excitation current, increased losses, and may also cause noise problems and vibration problems, affecting the normal operation of the transformer. Therefore, it is necessary to analyze and calculate the influence of the frequency and content changes of the inter-harmonic voltage excitation on the excitation characteristics of the iron core;

[0004] In the prior art, obtaining the excitation characteristics often adopts the method of multi-physical field coupling. The calculation process is complex, time-consuming, and the accuracy is not high. Especially for the excitation conditions under different excitations, it is often necessary to recalculate separately for different excitation conditions. Summary of the Invention

[0005] The present invention provides a finite element calculation method, device, and terminal for the excitation characteristics of a transformer core, so as to realize the calculation of the excitation characteristics of the transformer with an iron core winding in a time-saving and efficient manner.

[0006] In a first aspect, the present invention provides a finite element calculation method for the excitation characteristics of a transformer core, including:

[0007] Establish a structural model of the transformer;

[0008] Perform mesh division on the structural model of the transformer to obtain a three-dimensional finite element magnetic field model;

[0009] Based on the three-dimensional finite element magnetic field model, obtain the transient current value and dynamic inductance value of the transformer winding through circuit calculation;

[0010] Based on the three-dimensional finite element magnetic field model, obtain the excitation current value and magnetic flux density distribution of the transformer core through magnetic field calculation.

[0011] In a possible implementation manner, after obtaining the transient current value and dynamic inductance value of the transformer winding, and the excitation current value and magnetic flux density distribution of the transformer core, the method further includes;

[0012] Based on the transient current value of the transformer winding and the magnetic flux density distribution of the transformer core, an electromagnetic coupling model is established by utilizing the electromagnetic coupling characteristics of the transformer;

[0013] Using the dynamic inductance value of the transformer winding and the exciting current value of the transformer core as parameters for cyclic iteration to achieve the indirect coupling of the transformer magnetic field and the circuit.

[0014] In a possible implementation, a structural model of the transformer is established, including;

[0015] Obtain window parameters, where the window parameters include the core window height and the core window width;

[0016] Obtain core parameters, where the core parameters include the core stack thickness, the core width, and the core height;

[0017] Obtain winding parameters, where the winding parameters include the number of winding turns and the winding dimensions;

[0018] Obtain electric field parameters, where the electric field parameters include the core density, the relative permittivity of the core, the conductivity of the core, the relative permittivity of the winding, the conductivity of the winding, the relative permittivity of the air, and the conductivity of the air;

[0019] Obtain magnetic field parameters, where the magnetic field parameters include the B-H magnetization curve of the core along the rolling direction, the B-H magnetization curve of the core along the direction perpendicular to the rolling direction, the relative permeability of the winding, and the relative permeability of the air;

[0020] Based on the window parameters, perform window setting for the structural model, based on the core parameters, perform core parameter setting for the structural model, based on the winding parameters, perform winding parameter setting for the structural model, based on the electric field parameters, perform electric field parameter setting for the structural model, based on the magnetic field parameters, perform magnetic field parameter setting for the structural model, and obtain the structural model of the transformer.

[0021] In a possible implementation, perform mesh generation on the structural model of the transformer, including;

[0022] Perform tetrahedral mesh generation on the core part, perform swept mesh generation on the winding coil part, and perform tetrahedral mesh generation on the air domain part;

[0023] Among them, the tetrahedral mesh for meshing the core part is finer than the tetrahedral mesh for meshing the air domain part.

[0024] In a possible implementation, based on the three-dimensional finite element magnetic field model, obtain the transient current value and the dynamic inductance value of the transformer winding through circuit calculation, including:

[0025] The transient current value and dynamic inductance value of the winding are obtained by solving based on a three-dimensional finite element magnetic field model and a preset differential equation of the transformer circuit;

[0026] The differential equation of the transformer circuit is:

[0027]

[0028] R is the resistance matrix of the circuit, v(t) is the instantaneous value of the power supply voltage, L D is the dynamic inductance matrix of the circuit, i is the transient current value of the winding, and t is the time.

[0029] In a possible implementation manner, based on the three-dimensional finite element magnetic field model, the exciting current value and magnetic flux density distribution of the transformer core are obtained through magnetic field calculation, including:

[0030] Substitute the transient current value into Maxwell's equations to calculate the magnetic flux density distribution and exciting current value of the transformer core;

[0031] Maxwell's equations are:

[0032]

[0033] In the formula: B is the magnetic flux density, J is the current density, H is the magnetic field strength, E is the electric field strength, and t is the time.

[0034] In a second aspect, the present invention provides a finite element calculation device for the exciting characteristics of a transformer core, including:

[0035] A model establishment module for establishing a structural model of the transformer;

[0036] A mesh generation module for performing mesh generation on the structural model of the transformer to obtain a three-dimensional finite element magnetic field model;

[0037] A data acquisition module for obtaining the transient current value and dynamic inductance value of the transformer winding through circuit calculation based on the three-dimensional finite element magnetic field model;

[0038] A data operation module for obtaining the exciting current value and magnetic flux density distribution of the transformer core through magnetic field calculation based on the three-dimensional finite element magnetic field model.

[0039] In a possible implementation manner, the model establishment module is further used for:

[0040] Obtaining window parameters, where the window parameters include the core window height and the core window width;

[0041] Obtaining core parameters, where the core parameters include the core stack thickness, the core width, and the core height;

[0042] Obtain winding parameters, where the winding parameters include the number of winding turns and the winding size;

[0043] Obtain electric field parameters, where the electric field parameters include core density, core relative permittivity, core conductivity, winding relative permittivity, winding conductivity, air relative permittivity, and air conductivity;

[0044] Obtain magnetic field parameters, where the magnetic field parameters include the B-H magnetization curve of the core along the rolling direction, the B-H magnetization curve of the core along the direction perpendicular to the rolling direction, winding relative permeability, and air relative permeability;

[0045] Perform window setting of the structural model based on window parameters, perform core parameter setting of the structural model based on core parameters, perform winding parameter setting of the structural model based on winding parameters, perform electric field parameter setting of the structural model based on electric field parameters, perform magnetic field parameter setting of the structural model based on magnetic field parameters, to obtain the structural model of the transformer.

[0046] In a third aspect, the present invention provides a terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method in the above first aspect or any possible implementation manner of the first aspect are implemented.

[0047] In a fourth aspect, the present invention provides a computer-readable storage medium, where the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method in the above first aspect or any possible implementation manner of the first aspect are implemented.

[0048] The present invention provides a finite element calculation method, device, and terminal for the excitation characteristics of a transformer core. First, establish a structural model of the transformer, and then perform mesh division on the structural model of the transformer to obtain a three-dimensional finite element magnetic field model; thereafter, based on the three-dimensional finite element magnetic field model, obtain the transient current value and dynamic inductance value of the transformer winding through circuit calculation; finally, based on the three-dimensional finite element magnetic field model, obtain the excitation current value and magnetic flux density distribution of the transformer core through magnetic field calculation. By establishing a structural model of the transformer and performing mesh division to obtain a three-dimensional finite element magnetic field model, the present invention can more accurately reflect the characteristics of transformers with iron-core windings. Through circuit calculation and magnetic field calculation, the excitation characteristic changes of the transformer core under different excitation conditions can be reflected more quickly and efficiently. Description of the Drawings

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0050] Figure 1 is the implementation flowchart of the finite element calculation method for the excitation characteristics of the transformer core provided by the embodiment of the present invention;

[0051] Figure 2 is the schematic diagram of the structural model of the transformer provided by the embodiment of the present invention;

[0052] Figure 3 is the schematic diagram of the B-H magnetization curve provided by the embodiment of the present invention;

[0053] Figure 4 is the schematic diagram of the three-dimensional finite element magnetic field model provided by the embodiment of the present invention;

[0054] Figure 5 is the schematic diagram of the magnetic flux density distribution of the three-dimensional finite element magnetic field model provided by the embodiment of the present invention;

[0055] Figure 6 is the schematic diagram of the calculated value and the theoretical value of the excitation current when an interharmonic voltage of 1.575V / 5Hz is added provided by the embodiment of the present invention;

[0056] Figure 7 is the schematic diagram of the calculated value and the theoretical value of the excitation current when an interharmonic voltage of 1.575V / 10Hz is added provided by the embodiment of the present invention;

[0057] Figure 8 is the structural schematic diagram of the finite element calculation device for the excitation characteristics of the transformer core provided by the embodiment of the present invention;

[0058] Figure 9 is the schematic diagram of the terminal provided by the embodiment of the present invention. Detailed implementation manners

[0059] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are presented to thoroughly understand the embodiments of the present invention. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details. In other cases, the detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present invention.

[0060] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will explain through specific embodiments in conjunction with the accompanying drawings.

[0061] Refer to Figure 1 , which shows the implementation flowchart of the finite element calculation method for the excitation characteristics of a transformer core provided by an embodiment of the present invention, and is described in detail as follows:

[0062] Step S110: Establish a structural model of the transformer.

[0063] In this embodiment, a simulation software is used to establish a structural model of the transformer according to the window parameters of the transformer core, the core parameters of the transformer, the winding parameters of the transformer core, the electric field parameters of the transformer, and the magnetic field parameters of the transformer, as shown in Figure 2 .

[0064] Specifically, obtain the window parameters, which include the core window height and the core window width; for example, the core window height is 130 mm and the core window width is 70 mm.

[0065] Obtain the core parameters, which include the core stack thickness, the core width, and the core height; for example, the core stack thickness is 66 mm, the core width is 200 mm, and the core height is 260 mm.

[0066] Obtain the winding parameters, which include the number of winding turns and the winding size; for example, the number of winding turns is 20 turns, and the winding size is a square coil structure with a height of 60 mm and a thickness of 4 mm.

[0067] Obtain the electric field parameters, which include the core density, the relative permittivity of the core, the conductivity of the core, the relative permittivity of the winding, the conductivity of the winding, the relative permittivity of the air, and the conductivity of the air; for example, the core density is 7650 kg / m 3 , the relative permittivity of the core is 1, the conductivity of the core is 5 S / m, the relative permittivity of the winding is 1, the conductivity of the winding is 5 S / m, the relative permittivity of the air is 1, and the conductivity of the air is 5 S / m.

[0068] Obtain the magnetic field parameters, which include the B-H magnetization curve of the core along the rolling direction, the B-H magnetization curve of the core along the direction perpendicular to the rolling direction, the relative permeability of the winding, and the relative permeability of the air; for example, the B-H magnetization curve of the core along the rolling direction and the B-H magnetization curve of the core along the direction perpendicular to the rolling direction are as shown in Figure 3 , the relative permeability of the winding is 5 S / m, and the relative permeability of the air is 5 S / m.

[0069] Perform window settings for the structural model based on window parameters, perform core parameter settings for the structural model based on core parameters, perform winding parameter settings for the structural model based on winding parameters, perform electric field parameter settings for the structural model based on electric field parameters, perform magnetic field parameter settings for the structural model based on magnetic field parameters, and obtain the structural model of the transformer.

[0070] Step S120: Perform mesh division on the structural model of the transformer to obtain a three-dimensional finite element magnetic field model.

[0071] In this embodiment, use simulation software to perform mesh division on the structural model of the transformer to obtain a three-dimensional finite element magnetic field model, as Figure 4 shown.

[0072] Specifically, the structural model includes a core part, a winding coil part, and an air domain part.

[0073] Specifically, perform tetrahedral mesh division on the core part, perform swept mesh division on the winding coil part, and perform tetrahedral mesh division on the air domain part to obtain a three-dimensional finite element magnetic field model.

[0074] Specifically, the tetrahedral mesh for dividing the core part is finer than the tetrahedral mesh for dividing the air domain part.

[0075] Exemplarily, when performing mesh division on the structural model of the transformer, the complete mesh contains 69432 domain units, 8732 boundary elements, and 887 edge elements.

[0076] Step S130: Based on the three-dimensional finite element magnetic field model, obtain the transient current value and dynamic inductance value of the transformer winding through circuit calculation.

[0077] In this embodiment, use simulation software, according to the three-dimensional finite element magnetic field model and the preset differential equation of the transformer circuit, to obtain the transient current value and dynamic inductance value of the transformer winding through circuit simulation calculation.

[0078] Specifically, solve the transient current value and dynamic inductance value of the winding based on the three-dimensional finite element magnetic field model and the preset differential equation of the transformer circuit;

[0079] The differential equation of the transformer circuit is:

[0080]

[0081] R is the resistance matrix of the circuit, v(t) is the instantaneous value of the power supply voltage, L D is the dynamic inductance matrix of the circuit, i is the transient current value of the winding, and t is the time.

[0082] Exemplarily, in order to improve the calculation accuracy, a solver is set, and a directly fully coupled calculation mode is selected. The solution step size is set to 0.2 ms and the solution time is set to 2000 ms. Among them, the smaller the solution step size, the higher the solution accuracy.

[0083] Step S140: Based on the three-dimensional finite element magnetic field model, the excitation current value and the magnetic flux density distribution of the transformer core are obtained through magnetic field calculation.

[0084] In this embodiment, a simulation software is used to calculate the excitation current value and the magnetic flux density distribution of the transformer core through magnetic field simulation according to the transient current value and Maxwell's equations.

[0085] Specifically, the transient current value is substituted into Maxwell's equations to calculate the magnetic flux density distribution and the excitation current value of the transformer core;

[0086] Maxwell's equations are:

[0087]

[0088] In the formula: B is the magnetic flux density, J is the current density, H is the magnetic field strength, E is the electric field strength, t is the time,

[0089] Define the vector magnetic potential A, and let The electromagnetic field differential equation of the transformer core is obtained, and the magnetic flux density distribution and the excitation current value of the transformer core are calculated;

[0090] The electromagnetic field differential equation of the transformer core is:

[0091]

[0092] In the formula: J c Coil current density; μ is the magnetic resistivity; η is the conductivity.

[0093] Optionally, after obtaining the transient current value and the dynamic inductance value of the transformer winding, as well as the excitation current value and the magnetic flux density distribution of the transformer core,

[0094] Based on the transient current value of the transformer winding and the magnetic flux density distribution of the transformer core, an electromagnetic coupling model is established by using the electromagnetic coupling characteristics of the transformer;

[0095] Using the dynamic inductance value of the transformer winding and the excitation current value of the transformer core as parameters for cyclic iteration to achieve indirect coupling of the transformer magnetic field and the circuit.

[0096] In a possible implementation manner, a sinusoidal voltage with a frequency of 50 Hz and an amplitude of 52.5 V is applied to the winding, and the magnetic flux density distribution of the three-dimensional finite element magnetic field model can be obtained as Figure 5As shown, the magnetic flux density distribution of the iron core is 1.3T, which is basically equal to the theoretical value of the iron core, indicating that the three-dimensional finite element model can accurately calculate the magnetic flux density distribution of the iron core.

[0097] In a possible implementation, excitations with a frequency of 50Hz and an amplitude of 52.5V are applied to the winding, respectively added with: 0.525V (1% of the fundamental frequency) / 5Hz inter-harmonic voltage, 1.575V (3% of the fundamental frequency) / 5Hz inter-harmonic voltage, 1.35V (3% of the fundamental frequency) / 10Hz inter-harmonic voltage, 1.35V (3% of the fundamental frequency) / 7Hz inter-harmonic voltage, 2.625V (5% of the fundamental frequency) / 5Hz inter-harmonic voltage. Based on the three-dimensional finite element magnetic field model, the magnetic flux density distribution is calculated, and the calculated values are compared with the theoretical values. The error situation is shown in Table 1, which proves that this model can accurately reflect the change of the magnetic flux density of the iron core under the inter-harmonic voltage.

[0098]

[0099] Table 1

[0100] In a possible implementation, when a voltage of 50Hz and an amplitude of 52.5V are applied to the winding and 1.575V / 5Hz inter-harmonic voltage is added, the exciting current is calculated based on the three-dimensional finite element magnetic flux density model, and the calculated value and the theoretical value of the exciting current are as Figure 6 shown; when a voltage of 50Hz and an amplitude of 52.5V are applied to the winding and 1.575V / 10Hz inter-harmonic voltage is added, the exciting current is calculated based on the three-dimensional finite element magnetic flux density model, and the calculated value and the theoretical value of the exciting current are as Figure 7 shown, which proves that the three-dimensional finite element magnetic field model can accurately reflect the change of the exciting current of the iron core under the inter-harmonic voltage.

[0101] In the embodiment of the present invention, first, a structural model of the transformer is established. Then, the structural model of the transformer is meshed to obtain a three-dimensional finite element magnetic field model. Then, based on the three-dimensional finite element magnetic field model, the transient current value and the dynamic inductance value of the transformer winding are obtained through circuit calculation. Finally, based on the three-dimensional finite element magnetic field model, the exciting current value and the magnetic flux density distribution of the transformer iron core are obtained through magnetic field calculation. In this way, the changes occurring in the transformer with an iron core winding under the influence of inter-harmonic voltage can be reflected by the magnetic flux density distribution, the dynamic inductance value, the transient current value, and the exciting current value.

[0102] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0103] Based on the finite element calculation method for the excitation characteristics of the transformer core provided in the above embodiments, correspondingly, the present invention also provides a specific implementation manner of a device for the finite element calculation method of the excitation characteristics of the transformer core applied to the finite element calculation method of the excitation characteristics of the transformer core. Please refer to the following embodiments.

[0104] Figure 8 FIG. 4 shows a schematic structural diagram of a finite element calculation device for the excitation characteristics of a transformer core provided by an embodiment of the present invention. For ease of description, only parts related to the embodiments of the present invention are shown and are described in detail as follows:

[0105] As Figure 8 shown in FIG. 9, the finite element calculation device 800 for the excitation characteristics of the transformer core includes: a model establishment module 810, a mesh generation module 820, a data acquisition module 830, and a data operation module 840.

[0106] The model establishment module 810 is configured to establish a structural model of the transformer.

[0107] The mesh generation module 820 is configured to perform mesh generation on the structural model of the transformer to obtain a three-dimensional finite element magnetic field model.

[0108] The data acquisition module 830 is configured to obtain the transient current value and dynamic inductance value of the transformer winding through circuit calculation based on the three-dimensional finite element magnetic field model.

[0109] The data operation module 840 is configured to obtain the excitation current value and magnetic flux density distribution of the transformer core through magnetic field calculation based on the three-dimensional finite element magnetic field model.

[0110] In a possible implementation manner, the model establishment module 810 is specifically configured to:

[0111] Obtain window parameters, where the window parameters include the core window height and the core window width;

[0112] Obtain core parameters, where the core parameters include the core stack thickness, the core width, and the core height;

[0113] Obtain winding parameters, where the winding parameters include the number of winding turns and the winding dimensions;

[0114] Obtain electric field parameters, where the electric field parameters include the core density, the core relative permittivity, the core conductivity, the winding relative permittivity, the winding conductivity, the air relative permittivity, and the air conductivity;

[0115] Obtain magnetic field parameters, where the magnetic field parameters include the B-H magnetization curve of the core along the rolling direction, the B-H magnetization curve of the core along the direction perpendicular to the rolling direction, the winding relative permeability, and the air relative permeability;

[0116] Set the window of the structural model based on window parameters, set the core parameters of the structural model based on core parameters, set the winding parameters of the structural model based on winding parameters, set the electric field parameters of the structural model based on electric field parameters, set the magnetic field parameters of the structural model based on magnetic field parameters, and obtain the structural model of the transformer.

[0117] In a possible implementation manner, the mesh generation module 820 is specifically configured to:

[0118] The structural model includes a core part, a winding coil part, and an air domain part;

[0119] Performing mesh generation on the structural model of the transformer includes:

[0120] Performing tetrahedral mesh generation on the core part, performing swept mesh generation on the winding coil part, and performing tetrahedral mesh generation on the air domain part;

[0121] Among them, the tetrahedral mesh for meshing the core part is finer than the tetrahedral mesh for meshing the air domain part.

[0122] In a possible implementation manner, the data acquisition module 830 is specifically configured to:

[0123] Solve based on the three-dimensional finite element magnetic field model and the preset differential equation of the transformer circuit to obtain the transient current value and the dynamic inductance value;

[0124] The differential equation of the transformer circuit is:

[0125]

[0126] R is the resistance matrix of the circuit, v(t) is the instantaneous value of the power supply voltage, L D is the dynamic inductance matrix of the circuit, i is the transient current value of the winding, and t is the time.

[0127] In a possible implementation manner, the data operation module 840 is specifically configured to:

[0128] Substitute the transient current value into the Maxwell equation to calculate the magnetic flux density distribution and the exciting current value of the transformer core;

[0129] The Maxwell equation is:

[0130]

[0131] In the formula: B is the magnetic flux density, J is the current density, H is the magnetic field strength, E is the electric field strength, and t is the time.

[0132] In a possible implementation manner, the data operation module 840 is also specifically configured to:

[0133] After obtaining the transient current value and dynamic inductance value of the transformer winding, as well as the exciting current value and magnetic flux density distribution of the transformer core;

[0134] Based on the transient current value of the transformer winding and the magnetic flux density distribution of the transformer core, an electromagnetic coupling model is established by using the electromagnetic coupling characteristics of the transformer;

[0135] Using the dynamic inductance value of the transformer winding and the exciting current value of the transformer core as parameters for cyclic iteration to achieve the indirect coupling of the transformer magnetic field and circuit.

[0136] Figure 9 It is a schematic diagram of the terminal provided by the embodiment of the present invention. As Figure 9 shown, the terminal 9 of this embodiment includes: a processor 90, a memory 91, and a computer program 92 stored in the memory 91 and operable on the processor 90. When the processor 90 executes the computer program 92, the steps in the above-mentioned embodiments of the finite element calculation method for the exciting characteristics of each transformer core are implemented, such as Figure 1 the steps S110 to S140 shown. Alternatively, when the processor 90 executes the computer program 92, the functions of each module / unit in the above-mentioned device embodiments are implemented, such as Figure 8 the functions of the modules 810 to 840 shown.

[0137] Exemplarily, the computer program 92 can be divided into one or more modules / units. The one or more modules / units are stored in the memory 91 and executed by the processor 90 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, and this instruction segment is used to describe the execution process of the computer program 92 in the terminal 9. For example, the computer program 92 can be divided into Figure 8 the modules 810 to 840 shown.

[0138] The terminal 9 can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The terminal 9 may include, but is not limited to, a processor 90 and a memory 91. Those skilled in the art can understand that Figure 9 this is only an example of the terminal 9 and does not constitute a limitation on the terminal 9. It may include more or fewer components than shown in the figure, or combine some components, or different components. For example, the terminal may further include input / output devices, network access devices, a bus, etc.

[0139] The so-called processor 90 may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0140] The memory 91 may be an internal storage unit of the terminal 9, such as the hard disk or memory of the terminal 9. The memory 91 may also be an external storage device of the terminal 9, such as a plug-in hard disk equipped on the terminal 9, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, etc. Further, the memory 91 may also include both the internal storage unit of the terminal 9 and the external storage device. The memory 91 is used to store the computer program and other programs and data required by the terminal. The memory 91 may also be used to temporarily store data that has been output or will be output.

[0141] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional unit and module is used as an example. In actual applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiments may be integrated into a processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of this application. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0142] In the above embodiments, the descriptions of the various embodiments have their own emphases. For parts not detailed or recorded in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0143] Those of ordinary skill in the art will realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. A professional technician can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0144] In the embodiments provided by the present invention, it should be understood that the disclosed device / terminal and method can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in an electrical, mechanical or other form.

[0145] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place, or they can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0146] In addition, the functional units in each embodiment of the present invention can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0147] When the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above-described embodiment methods of the present invention, it can also be completed by a computer program instructing relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-described embodiments of the finite element calculation method for the excitation characteristics of each transformer core can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0148] The above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A finite element calculation method for the excitation characteristics of a transformer core, characterized in that Including: Establishing a structural model of a transformer; Performing mesh generation on the structural model of the transformer to obtain a three-dimensional finite element magnetic field model; Solving based on the three-dimensional finite element magnetic field model and a preset differential equation of the transformer circuit to obtain the transient current value and dynamic inductance value of the transformer winding; Substituting the transient current value into Maxwell's equations to calculate the exciting current value and magnetic flux density distribution of the transformer core.

2. The finite element calculation method for the excitation characteristics of the transformer core according to claim 1, characterized in that, After obtaining the transient current value and dynamic inductance value of the transformer winding, and the exciting current value and magnetic flux density distribution of the transformer core, the method further includes: Establishing an electromagnetic coupling model based on the transient current value of the transformer winding and the magnetic flux density distribution of the transformer core by using the electromagnetic coupling characteristics of the transformer; Performing cyclic iteration with the dynamic inductance value of the transformer winding and the exciting current value of the transformer core as parameters to achieve indirect coupling of the transformer magnetic field and circuit.

3. The finite element calculation method for the excitation characteristics of a transformer core according to claim 1 or 2, characterized in that, The establishing of the structural model of the transformer includes: Obtaining window parameters, where the window parameters include the core window height and core window width; Obtaining core parameters, where the core parameters include the core stack thickness, core width, and core height; Obtaining winding parameters, where the winding parameters include the number of winding turns and winding dimensions; Obtaining electric field parameters, where the electric field parameters include the core density, relative permittivity of the core, conductivity of the core, relative permittivity of the winding, conductivity of the winding, relative permittivity of air, and conductivity of air; Obtaining magnetic field parameters, where the magnetic field parameters include the B-H magnetization curve of the core along the rolling direction, the B-H magnetization curve of the core along the direction perpendicular to the rolling direction, relative permeability of the winding, and relative permeability of air; Performing window setting of the structural model based on the window parameters, performing core parameter setting of the structural model based on the core parameters, performing winding parameter setting of the structural model based on the winding parameters, performing electric field parameter setting of the structural model based on the electric field parameters, and performing magnetic field parameter setting of the structural model based on the magnetic field parameters to obtain the structural model of the transformer.

4. The finite element calculation method for the excitation characteristics of a transformer core according to claim 3, characterized in that, The structural model includes a core part, a winding coil part, and an air domain part; The performing mesh generation on the structural model of the transformer includes: Performing tetrahedral mesh generation on the core part, performing swept mesh generation on the winding coil part, and performing tetrahedral mesh generation on the air domain part; Among them, the tetrahedral mesh for meshing the core part is finer than the tetrahedral mesh for meshing the air domain part.

5. The finite element calculation method for the excitation characteristics of a transformer core according to claim 4, characterized in that The differential equation of the transformer circuit is: R is the resistance matrix of the circuit, v(t) is the instantaneous value of the power supply voltage, L D is the dynamic inductance matrix of the circuit, i is the transient current value of the winding, and t is time.

6. The finite element calculation method for the excitation characteristics of a transformer core according to claim 1, characterized in that, Maxwell's equations are: In the formula: B is the magnetic flux density, J is the current density, H is the magnetic field strength, E is the electric field strength, and t is the time.

7. A finite element calculation device for the excitation characteristics of a transformer core, characterized in that, Including: A model establishment module for establishing a structural model of a transformer; A mesh generation module for performing mesh generation on the structural model of the transformer to obtain a three-dimensional finite element magnetic field model; A data acquisition module for solving based on the three-dimensional finite element magnetic field model and a preset differential equation of the transformer circuit to obtain the transient current value and dynamic inductance value of the transformer winding; A data operation module for substituting the transient current value into Maxwell's equations to calculate the exciting current value and magnetic flux density distribution of the transformer core.

8. The finite element calculation device for the excitation characteristics of a transformer core according to claim 7, characterized in that, The model establishment module includes: A first acquisition unit, configured to acquire window parameters, where the window parameters include the core window height and the core window width; A second acquisition unit, configured to acquire core parameters, where the core parameters include the core stack thickness, the core width, and the core height; A third acquisition unit, configured to acquire winding parameters, where the winding parameters include the number of winding turns and the winding size; A fourth acquisition unit, configured to acquire electric field parameters, where the electric field parameters include the core density, the relative permittivity of the core, the conductivity of the core, the relative permittivity of the winding, the conductivity of the winding, the relative permittivity of air, and the conductivity of air; A fifth acquisition unit, configured to acquire magnetic field parameters, where the magnetic field parameters include the B-H magnetization curve of the core along the rolling direction, the B-H magnetization curve of the core along the direction perpendicular to the rolling direction, the relative permeability of the winding, and the relative permeability of air; A model creation unit, configured to perform window setting of the structural model based on the window parameters, perform core parameter setting of the structural model based on the core parameters, perform winding parameter setting of the structural model based on the winding parameters, perform electric field parameter setting of the structural model based on the electric field parameters, and perform magnetic field parameter setting of the structural model based on the magnetic field parameters, so as to obtain the structural model of the transformer.

9. A terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, the steps of the finite element calculation method for the excitation characteristics of the transformer core as described in any one of claims 1 to 6 above are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, the steps of the finite element calculation method for the excitation characteristics of the transformer core as described in any one of claims 1 to 6 above are implemented.

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