Design Method of Scaled-Down Model of High-Power High-Frequency Transformer Based on the Principle of Constant Frequency

Abstract

The present invention relates to the technical field of high-frequency transformers, and provides a design method for a scaled-down model of a high-power high-frequency transformer based on the principle of invariant frequency. The method includes: performing equal-proportion scaling on the physical dimensions of the original model to determine the geometric scaling coefficient between the scaled-down model and the original model; based on the geometric scaling coefficient, deriving the scaling relationship of electromagnetic field parameters and calculating the electromagnetic field parameters of the scaled-down model; calculating the winding loss and core loss of the scaled-down model based on the scaling criterion of loss temperature rise parameters; constructing a three-dimensional model of multi-physical field coupling of a high-frequency transformer based on a finite element simulation platform, performing similarity processing on the three-dimensional model of multi-physical field coupling of the high-frequency transformer to obtain a scaled-down model; and performing multi-field coupling simulation analysis on the scaled-down model to verify and optimize the electromagnetic and loss body characteristics of the scaled-down model.

Description

Technical Field

[0001] The present invention relates to the technical field of high-frequency transformers, and particularly to a design method for a scaled-down model of a high-power high-frequency transformer based on the principle of constant frequency. Background Art

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

[0003] The design and manufacture of high-power high-frequency transformers face a series of challenges, especially the integrated design of multiple fields such as electromagnetics, heat, and insulation in a compact space. Under high-frequency conditions, factors such as magnetic hysteresis and eddy current losses in the magnetic core, skin effect and proximity effect in the windings will cause a significant increase in losses. In addition, unoptimized distributed parameters will exacerbate the electromagnetic interference problem of electronic circuits, affecting the stability and efficiency of the overall equipment. To deeply study and optimize the design of high-frequency transformers, conducting experiments and tests on actual physical models is usually costly and complex. Summary of the Invention

[0004] To solve the technical problems existing in the above background art, the present invention provides a design method for a scaled-down model of a high-power high-frequency transformer based on the principle of constant frequency. The present invention can predict and analyze the electromagnetic characteristics and working efficiency of the prototype transformer while reducing the cost of large-scale initial experiments. By verifying the scaled-down model through experiments, potential problems in the design can be effectively discovered in advance and optimized accordingly, so as to achieve higher performance and stability in practical applications.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention provides a design method for a scaled-down model of a high-power high-frequency transformer based on the principle of constant frequency.

[0007] A design method for a scaled-down model of a high-power high-frequency transformer based on the principle of constant frequency includes:

[0008] Scaling the physical dimensions of the original model proportionally to determine the geometric scaling coefficient between the scaled-down model and the original model;

[0009] Based on the geometric scaling coefficient, deriving the scaling relationship of electromagnetic field parameters and calculating the electromagnetic field parameters of the scaled-down model;

[0010] Calculating the winding loss and core loss of the scaled-down model based on the scaling criterion of loss temperature rise parameters;

[0011] Constructing a three-dimensional multi-physics coupling model of a high-frequency transformer based on a finite element simulation platform, and performing similarity processing on the three-dimensional multi-physics coupling model of the high-frequency transformer to obtain the scaled-down model;

[0012] Perform multi-field coupling simulation analysis on the scaled model to verify and optimize the electromagnetic and loss body characteristics of the scaled model.

[0013] Furthermore, based on the scaling criterion of loss temperature rise parameters, calculate the winding loss and core loss of the scaled model; the method includes: adjusting the core loss through the Steinmetz formula and calculating the winding loss using the modified Dowell model processed by FFT to ensure that the temperature rise of the scaled model is consistent with that of the original model.

[0014] Furthermore, the scaling criterion based on loss temperature rise parameters includes: the winding loss is k 2n-3 times that of the original model, and the core loss is k (n-2)β times that of the original model, where β is the magnetic density index and n is the scaling power coefficient.

[0015] Furthermore, the electromagnetic field parameters include: current, voltage, resistance, leakage magnetic induction, conductance, capacitance, magnetic flux density, current density, and magnetic field strength.

[0016] Furthermore, after scaling: the current is k n-1 times that of the original model, the voltage is k n times that of the original model, the resistance is k -1 times that of the original model, the leakage inductance is k times that of the original model, the conductance is k times that of the original model, the capacitance is k times that of the original model, the magnetic flux density is k n-2 times that of the original model, the current density is k n-3 times that of the original model, and the magnetic field strength is k n-2 times that of the original model.

[0017] Furthermore, the physical dimensions include length and area.

[0018] Furthermore, after scaling: the length is k times that of the original model, and the area is k 2 times that of the original model.

[0019] The second aspect of the present invention provides a design system for a scaled model of a high-power high-frequency transformer based on the frequency invariance principle.

[0020] A design system for a scaled model of a high-power high-frequency transformer based on the frequency invariance principle includes:

[0021] A geometric scaling module configured to: perform proportional scaling on the physical dimensions of the original model to determine the geometric scaling coefficient between the scaled model and the original model;

[0022] An electromagnetic field scaling module configured to: deduce the scaling relationship of electromagnetic field parameters based on the geometric scaling coefficient and calculate the electromagnetic field parameters of the scaled model;

[0023] A loss reduction ratio module, which is configured to calculate the winding loss and core loss of the reduced-scale model based on the reduction ratio criterion of the loss temperature rise parameter;

[0024] A model construction module, which is configured to construct a three-dimensional multi-physical field coupling model of a high-frequency transformer based on a finite element simulation platform, perform similarity processing on the three-dimensional multi-physical field coupling model of the high-frequency transformer, and obtain a reduced-scale model;

[0025] A simulation optimization module, which is configured to perform multi-field coupling simulation analysis on the reduced-scale model, and verify and optimize the electromagnetic and loss body characteristics of the reduced-scale model.

[0026] The third aspect of the present invention provides a computer-readable storage medium.

[0027] A computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps in the design method of the reduced-scale model of the high-power high-frequency transformer based on the frequency invariance principle as described in the first aspect above are implemented.

[0028] The fourth aspect of the present invention provides a computer device.

[0029] A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the program, the steps in the design method of the reduced-scale model of the high-power high-frequency transformer based on the frequency invariance principle as described in the first aspect above are implemented.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] (1) Material selection and loss: In an extremely high-frequency environment, the material selection of the magnetic core and winding becomes more critical. Traditional materials may introduce higher magnetic core loss and winding loss, so high-performance materials, such as soft magnetic composite materials, need to be used to reduce the loss.

[0032] (2) Winding design: The electromagnetic induction and winding resistance of the winding will cause larger current and temperature rise. Therefore, the design of the winding needs to consider factors such as current density, heat dissipation ability, and material loss to ensure stability and long life.

[0033] (3) Core breakdown and insulation damage: By reducing the size for high-frequency testing, the failure points of the full-scale transformer can be predicted safely and economically, and the design can be optimized in advance to ensure the reliability and durability of the core and insulation materials in actual applications.

[0034] (5) Coupling and electromagnetic interference: High-frequency operation may cause between windings: the hysteresis and eddy current losses of the core will increase significantly, and the design of the core needs to consider minimizing these losses.

[0035] (4) Insulation: High-frequency voltage can cause a greater electric field strength in the insulating material. Therefore, the insulation system needs to be specially designed to prevent the increase in coupling between them, as well as the enhancement of electromagnetic radiation and interference. Measures such as reasonable layout and insulation need to be taken during design to reduce coupling and interference.

[0036] (6) Selection of electronic components: High-frequency transformers need to use high-frequency electronic components, such as high-frequency switching devices and capacitors. The selection and design of these components require a higher technical level, and at the same time, the power consumption and stability of the components need to be considered.

[0037] (7) Heat dissipation problem: Under high-frequency operation, the rapid changes in current and voltage in the transformer may lead to a greater power density. Therefore, heat dissipation design becomes particularly crucial to ensure that the system remains stable under high-load conditions. Description of the Drawings

[0038] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0039] Figure 1 is the topological structure of the MVA-level high-frequency transformer in this embodiment;

[0040] Figure 2 is the flowchart of the design method of the scaled-down model of the high-power high-frequency transformer based on the frequency-invariant principle in the embodiment;

[0041] Figure 3 is the no-load current and its FFT waveform diagram;

[0042] Figure 4 is the magnetic flux density distribution of the original model of the high-frequency transformer (1 / 4 cycle);

[0043] Figure 5 is the magnetic flux density distribution of the scaled-down model of the high-frequency transformer (1 / 4 cycle);

[0044] Figure 6 is the loss and efficiency curve of the high-frequency transformer. Detailed Embodiment

[0045] The present invention will be further described below in conjunction with the drawings and embodiments.

[0046] It should be noted that the following detailed descriptions are all illustrative and are intended to provide a further description of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0047] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should also be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0048] It should be noted that the flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of methods and systems according to various embodiments of the present disclosure. It should be noted that each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the module, program segment, or part of code may include one or more executable instructions for implementing the logical functions specified in each embodiment. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the flowchart and / or block diagram, and the combinations of blocks in the flowchart and / or block diagram, can be implemented using a dedicated hardware-based system for performing the specified functions or operations, or can be implemented using a combination of dedicated hardware and computer instructions.

[0049] Embodiment 1

[0050] In order to solve the problems such as the difficulty in designing and analyzing the full-size model of a large-capacity high-frequency transformer, the high requirements for the test site, and the difficulty in testing the dynamic performance, a scaled-down model design is carried out taking a megavolt-ampere high-frequency transformer as an example. This high-frequency transformer adopts a single-phase double-winding topology structure, the winding is wound with high-conductivity copper foil, and a U-shaped iron core is selected. As Figure 1 shown, this 1MVA, 10kHz high-frequency transformer is driven by a DC-DC bidirectional DC conversion circuit. The method for designing a scaled-down model of a high-power high-frequency transformer based on the principle of constant frequency described in this embodiment, as Figure 2 shown, includes the following steps:

[0051] Step 1: List the basic Maxwell electromagnetic field equations.

[0052] To better describe the changes in the electromagnetic field in the scaled-down model, first introduce Maxwell's equations as the basic theoretical framework:

[0053]

[0054] Among them, E is the electric field strength, D is the electric displacement vector, t is the time, B is the magnetic induction intensity, Qf is the free charge, Ф B is the magnetic flux, I f is the free current passing through the closed loop L, Ф D is the electric flux.

[0055] In some embodiments, for the scaled - down derivation in combination with other equations, the following additional equations are added:

[0056]

[0057] where J is the current density, ρ is the conductivity, ε0 is the vacuum permittivity, χ e is the electric susceptibility, μ0 is the vacuum permeability, χ m is the magnetic susceptibility, U is the voltage, k1 is a constant coefficient with a value of 4.44, f is the operating frequency, N is the number of turns of the coil, and S is the cross - sectional area of the magnetic circuit.

[0058] Step 2: Scaled - down derivation of Maxwell's equations.

[0059] When designing the scaled - down model, the length, width, and radius are reduced proportionally according to the scaling factor k. Therefore, the scaling factor k x of the physical dimension x = k.

[0060] During the production process of the scaled - down model, the materials remain the same. Therefore, the property constants of the scaled - down model and the original model are the same, that is, the dielectric constant, conductivity, permeability, and resistivity of the scaled - down model are the same as those of the original model, which means the scaling factors of these physical quantities are all 1.

[0061] Assuming the scaling factor is k, the similarity relationship of each physical quantity is expressed as () = k () ()’. For example, E = k E E’, the electric field strength of the actual model is E, the electric field strength of the scaled - down model is E’, and the scaling factor is k E .

[0062] In practical applications, this similarity relationship means that during the scaling process, while maintaining the proportional relationship unchanged, the physical quantity is adjusted by the scaling power coefficient n. Specifically, the physical quantity of the actual model can be regarded as n times that of the scaled - down model, so as to achieve strict similarity and comparability in electromagnetic characteristics between the two.

[0063] According to Maxwell's equations, the Maxwell's equations that should be satisfied after scaling are:

[0064]

[0065] In some embodiments, substituting the original model variables can obtain:

[0066]

[0067] According to the similarity theory and simplifying the formula, using known scaling factors such as size, dielectric constant, conductivity, etc. as the most basic scaling factors, the following relationships are obtained:

[0068]

[0069] Step 3: Derivation of the scaling relationship of winding parameters

[0070] Derivation of the scaling relationship of distributed capacitance parameters:

[0071] The distributed capacitance of a high-frequency transformer mainly refers to the inter-turn capacitance, inter-layer capacitance, and winding capacitance. When the system voltage level and frequency are very high, the influence of the distributed capacitance on the overall circuit becomes more significant. Therefore, the influence of the distributed capacitance of a high-frequency transformer on system stability, device loss, noise interference, etc. cannot be ignored.

[0072] For a high-frequency transformer with a rectangular magnetic core column and wound with copper foil, each layer of the winding can be regarded as the plate of a capacitor. Assuming the winding has two layers, the calculation formula for the distributed capacitance is:

[0073]

[0074] Among them, ε0 and ε1 are the vacuum permittivity and relative permittivity respectively, S is the effective area of the plate, and d is the distance between the plates.

[0075] Therefore, the scaling relationship of the distributed capacitance is as follows:

[0076]

[0077] According to the similarity theory and simplifying the above formula, the following relationship is obtained:

[0078] k C = k ε k ε k S / k d = k

[0079] Derivation of the scaling relationship of leakage inductance parameters:

[0080] The definition of leakage flux is the flux that links only the primary or secondary winding turns. The leakage flux stores magnetic field energy, and this effect is reflected by the leakage inductance parameter. Due to the existence of leakage inductance in a high-frequency transformer, the leakage inductance energy is released in the circuit at the moment when the switching tube turns off, and the generated reverse voltage is an important factor that damages the switching tube. Therefore, accurately calculating the leakage inductance is the key point of the refined design of a high-frequency transformer.

[0081] The analytical method is a method for indirectly calculating the leakage inductance by calculating the magnetic leakage energy or magnetic flux linkage. The analytical method has lower accuracy than the numerical method, but the calculation process is simple and the calculation speed is fast. Therefore, in practical engineering, the leakage inductance of high-frequency transformers is more often calculated by the analytical method. Then, the leakage inductance of the high-frequency transformer calculated by the energy method is as follows:

[0082]

[0083] Among them, L σ is the leakage inductance, μ is the magnetic permeability, and H is the magnetic field strength.

[0084] From the above leakage inductance formula, its scaling ratio relationship can be obtained as:

[0085]

[0086] According to the similarity theory and simplifying the above formula, the following relationship is obtained:

[0087]

[0088] Derivation of the scaling ratio relationship of resistance parameters:

[0089] The calculation formula for the resistance parameter with the turn as the basic unit of the model is as follows:

[0090]

[0091] In the formula, l w is the wire length; S w is the cross-sectional area of the wire; ρ is the resistivity.

[0092] Resistance parameter Therefore, the scaling equivalence of the resistance is as follows:

[0093] k R = k ρ / k x

[0094] Derivation of the scaling ratio relationship of conductance parameters:

[0095] The calculation formula for the conductance G is as follows:

[0096]

[0097] In the formula, C is the capacitance; ε is the dielectric constant of the medium; σ is the conductivity of the conductor.

[0098] Conductance parameter Therefore, the scaling equivalence of the conductance is as follows:

[0099]

[0100] Based on the operating frequency f, that is, kf =1. At the same time, since the materials remain the same during the production of the scaled model, the property constants of the scaled model and the original model are the same, so k μ =k ε =k σ =1, size reduction factor k x = k, take k U =k n , accordingly, k B =k n-2 , k I =k n-1 , k H =k n-2 , k E =k n-3 , k D =k n-3 , k J =k n-3 , n is the scaling power coefficient, and the electromagnetic parameters based on the scaling criterion (frequency remains unchanged) are shown in Table 1.

[0101] Table 1 Electromagnetic parameters based on the scaling criterion (frequency unchanged)

[0102]

[0103] The no-load current of the original model (OM) and the scaled model (SM) are simulated, and the harmonic components are analyzed by Fourier decomposition. The no-load current and its FFT waveform are shown in the figure below. Figure 3 As shown. The results show that the no-load current amplitudes of the original model and the scaled model are 0.42A and 0.11A respectively. Since the voltage source excitation is applied to the primary side and the initial current is set to 0, the no-load current in one cycle is positive and presents a triangular waveform. Through Fourier decomposition analysis, the main harmonics of the two models are odd harmonics, and the harmonic amplitudes meet the scale factor of k times.

[0104] The magnetic induction intensity of the original model (OM) and the scaled model (SM) of the high-frequency transformer is simulated. m They are 1.17T and 1.14T respectively. Figure 4 and Figure 5 As shown. The results show that the magnetic flux density distribution of the two models is basically the same. By comparing the magnetic induction intensity of OM and SM, it can be seen that in models of different sizes, the electromagnetic characteristics of the two are the same. Under the condition that the frequency remains unchanged, SM accurately reflects the electromagnetic behavior of OM.

[0105] Step 4: Derivation of the scaling relationship of loss temperature rise parameters

[0106] Derivation of the reduction ratio of core loss:

[0107] Taking the improved generalized Steinmetz equation (IGSE) as an example, the core loss \(P\) of a high-frequency transformer under any waveform excitation is calculated core , and the formula is as follows:

[0108]

[0109] where \(k\) i is the loss correction coefficient, \(\beta\) is the magnetic flux density exponent, \(f\) is the frequency; \(B\) m is the magnetic flux density amplitude.

[0110] Therefore, the scaling relationship of the core loss is as follows:

[0111]

[0112] According to the similarity theory and simplifying the above formula, the following relationship is obtained:

[0113]

[0114] Derivation of the scaling relationship of winding loss:

[0115] In the practical application of high-frequency transformers, the external excitation usually adopts a non-sinusoidal waveform (such as a square wave), while the traditional Dowell model is for the excitation scenario of a sinusoidal waveform and is difficult to be directly applied to non-sinusoidal excitation conditions. Therefore, in order to accurately calculate the loss of the winding under non-sinusoidal excitation, the excitation signal needs to be processed by FFT, decomposed into multiple harmonic components, and the modified Dowell model is applied to calculate the loss based on each harmonic component respectively. Finally, the losses of each harmonic component are added to obtain the total loss, thus forming a method for calculating the winding loss under non-sinusoidal excitation. The modified winding loss calculation formula under non-sinusoidal excitation is:

[0116]

[0117] where \(R\) dc , \(R\) ac are the DC resistance and AC resistance respectively, \(I\) dc , \(I\) rms are the DC current and the effective value of the current under each order of harmonics respectively, \(I\) rms(n) , \(R\) ac(n) are the effective value of the current and the AC resistance under the \(n\)th harmonic respectively, \(F\) rn is the AC resistance coefficient.

[0118] Therefore, the scaling relationship of the winding loss is as follows:

[0119]

[0120] According to the similarity theory and simplifying the above formula, the following relationship is obtained:

[0121]

[0122] Table 2 Scaling criteria for loss temperature rise parameters (constant frequency)

[0123]

[0124] The scaling criteria for loss temperature rise parameters (constant frequency) are shown in Table 2. In the scaling design of high-frequency transformers, the selection of the scaling power coefficient n is to ensure the reasonable working state of electromagnetic parameters such as current density and magnetic flux density in the scaled model and the original model. This means that during the scaling process, the scaling power coefficient n can be adjusted according to specific electromagnetic working conditions to maintain similar electromagnetic performance in the scaled model as in the original model.

[0125] As Figure 6 shown in the loss and efficiency curves of the high-frequency transformer, P Fe is positively correlated with both B m and f. When the working magnetic flux density B m is 0.4T and the frequency f is 10 kHz, the core loss corresponding to the scaled model (SM) is 25.82 W, which is basically consistent with the iron loss value of the original model (OM), meeting the scaling coefficient relationship of k (n-2)β = 1 times. To analyze the variation law of copper loss, a copper loss variation curve was established with the winding current and its density as independent variables. The data shows that when the SM is passed through a winding current of 28.6 A, the copper loss is 143.00 W, and the corresponding current value and copper loss value of the OM are 105.4 A and 549.64 W respectively, meeting the scaling relationship of k (2n-3) = 3.684 times. As the current increases, the copper loss shows a linear upward trend. The 3D point diagram shows the efficiency variation of the transformer at different magnetic flux densities and frequencies. When taking the rated parameters of the high-frequency transformer, the transformer efficiency reaches 99.87%.

[0126] Loss calculation and temperature rise analysis: Loss calculation is a very important part in the design of high-frequency transformers. Especially in high-power high-frequency transformers, winding loss and core loss are key factors affecting the performance and life of the transformer. To ensure that the scaled model can accurately reflect the loss characteristics of the prototype transformer, a calculation method based on the scaling criteria of loss and temperature rise is adopted:

[0127] Winding loss calculation: In a high-frequency transformer, winding loss is affected not only by the DC resistance but also by the skin effect and proximity effect. Based on the modified Dowell model and combined with the scaling factor k, the loss of the winding at high frequencies is calculated. The Dowell model can effectively describe the variation of current distribution in multi-layer windings. Therefore, through this model, the loss of the scaled model winding under high-frequency operation can be accurately evaluated. At the same time, the FFT (Fast Fourier Transform) is used to process the signal to correct the frequency response of the winding, ensuring that the loss characteristics of the scaled model are consistent with the original model.

[0128] Core loss calculation: Core loss consists of hysteresis loss and eddy current loss. To accurately calculate the core loss of the scaled model, the Steinmetz formula is adopted. This formula adjusts the loss characteristics of the core at different magnetic flux densities through the magnetic flux density exponent β. Through the scaled calculation of the core loss, it can be ensured that the loss characteristics of the scaled model are consistent with the original model at different operating frequencies and powers. At the same time, the frequency-scaling relationship is used for correction to ensure that the core temperature rise after scaling is consistent with that of the prototype transformer.

[0129] Temperature rise analysis: Based on the results of the loss calculation, the temperature rise analysis is further carried out. Through the loss distribution of the winding and the core, the distribution of heat sources in the transformer is calculated using the heat transfer analysis method. Considering the geometric dimensions and material properties of the scaled model, the scaled temperature rise analysis is carried out to predict the temperature rise of the model during actual operation. The results of the temperature rise analysis will be used to verify whether the heat dissipation performance of the scaled model is consistent with that of the prototype transformer and to guide the further optimization of the model.

[0130] Step 5: Perform a multi-field coupling simulation analysis on the scaled model to verify and optimize the electromagnetic and loss body characteristics of the scaled model.

[0131] (1) Multi-physics field coupling simulation: The performance of a high-frequency transformer is affected by the coupling of multiple physical fields, including the electromagnetic field, thermal field, and structural stress field, etc. Therefore, when designing the scaled model, it is necessary to verify the actual performance of the transformer through multi-physics field coupling simulation. The following are the specific simulation steps:

[0132] Electromagnetic field simulation: First, use finite element analysis software (such as ANSYS Maxwell or COMSOL) to construct a three-dimensional electromagnetic field simulation model of the transformer. Input the scaled geometric dimensions, material properties, and operating conditions into the model, and calculate key electromagnetic parameters such as magnetic flux distribution, magnetic induction intensity, and current density. Through the simulation, the electromagnetic performance of the scaled model can be evaluated, such as leakage magnetic flux, core saturation degree, and current distribution of the winding, etc., to ensure that the electromagnetic field behavior of the scaled model matches that of the prototype transformer.

[0133] Thermal field simulation: After the electromagnetic field simulation is completed, the electromagnetic loss results (including winding loss and core loss) are used as heat sources to input into the thermal field simulation. By simulating the heat conduction, convection, and radiation processes of the transformer, the temperature distribution and heat dissipation effect of the transformer are calculated. Special consideration should be given to the influence of the geometric dimensions of the scaled model on heat dissipation in thermal field simulation to ensure that the temperature rise of the model under high power is consistent with that of the prototype.

[0134] Stress field simulation: In high-power transformers, due to the effects of temperature changes and electromagnetic forces, thermal stress and mechanical stress will be generated in the windings and cores. Therefore, coupled stress field simulation is necessary. By performing stress analysis on the scaled model, potential deformations or structural damages that may occur in the transformer under high temperature and high electromagnetic force can be detected in advance, thereby optimizing the structural design.

[0135] Through the coupled simulation of multiple physical fields, the performance of the scaled model in aspects such as electromagnetics, heat, and mechanics can be comprehensively evaluated to ensure that the performance of the model under different operating conditions is consistent with that of the prototype.

[0136] (2) Verification and optimization of simulation results: Verification of simulation results is a crucial step in ensuring the accuracy of the scaled model. By analyzing the simulation results of multiple physical fields, researchers can evaluate the electromagnetic performance, loss characteristics, and temperature rise of the scaled model to ensure that they are consistent with the performance of the prototype transformer. The specific verification process includes:

[0137] Electromagnetic performance verification: By analyzing parameters such as magnetic flux distribution, leakage magnetic flux, and current density in the simulation results, verify whether the scaled model can accurately reflect the electromagnetic performance of the prototype transformer. If problems such as magnetic flux saturation and excessive leakage magnetic flux are found, it may be necessary to adjust the winding layout or core material to optimize the model design.

[0138] Loss verification: Compare the loss values of the windings and cores to ensure that the losses of the scaled model are of the same order of magnitude as those of the original model. If the losses are too large or the temperature rise exceeds the standard, it may be necessary to readjust the scaling factor or improve the loss calculation model.

[0139] Temperature rise verification: By analyzing the temperature distribution in the thermal field simulation results, verify whether the temperature rise of the scaled model is consistent with that of the prototype. Focus on checking the highest temperature points of the windings and cores to ensure that they are within the design range. If the temperature rise is too high, it may be necessary to optimize the heat dissipation structure of the model or improve the material selection of the core and windings.

[0140] According to the verification results, adjust and optimize the design of the scaled model, including redefining the geometric scaling factor, electromagnetic structure, and material parameters. The optimized model needs to be subjected to simulation analysis again until the results meet the design requirements.

[0141] The present invention constructs a three-dimensional model of multi-field coupling for high-frequency transformers and derives a scale-down criterion based on frequency invariance applicable to the loss temperature rise mechanism of high-frequency transformers. Through the comparative analysis of electromagnetic loss and temperature rise characteristics such as magnetic field distribution, loss distribution, and temperature rise distribution before and after scale-down, the correctness of the scale-down criterion is verified. It effectively reduces unnecessary resource waste before the preparation of high-frequency transformers, solves problems such as the difficulty in designing and analyzing full-scale models of large-capacity high-frequency transformers, the high requirements for test sites, and the difficulty in dynamic performance testing. Taking a megavolt-ampere high-frequency transformer as an example, a scale-down model design is carried out. The high-frequency transformer adopts a single-phase double-winding topology, the winding is wound with high-conductivity copper foil, and the iron core is a U-shaped iron core.

[0142] Example Two

[0143] This embodiment provides a scale-down model design system for high-power high-frequency transformers based on the principle of frequency invariance.

[0144] A scale-down model design system for high-power high-frequency transformers based on the principle of frequency invariance includes:

[0145] A geometric scale-down module configured to: proportionally scale the physical dimensions of the original model to determine the geometric scale-down coefficient between the scale-down model and the original model;

[0146] An electromagnetic field scale-down module configured to: based on the geometric scale-down coefficient, derive the scale-down relationship of electromagnetic field parameters and calculate the electromagnetic field parameters of the scale-down model;

[0147] A loss scale-down module configured to: based on the scale-down criterion of loss temperature rise parameters, calculate the winding loss and core loss of the scale-down model;

[0148] A model construction module configured to: construct a three-dimensional model of multi-physical field coupling for high-frequency transformers based on a finite element simulation platform, and perform similarity processing on the three-dimensional model of multi-physical field coupling for high-frequency transformers to obtain a scale-down model;

[0149] A simulation optimization module configured to: perform multi-field coupling simulation analysis on the scale-down model to verify and optimize the electromagnetic and loss body characteristics of the scale-down model.

[0150] In some embodiments, the loss scale-down module is further configured to: adjust the core loss through the Steinmetz formula and calculate the winding loss using the modified Dowell model processed by FFT to ensure that the temperature rise of the scale-down model is consistent with that of the original model.

[0151] In some embodiments, the scale-down criterion based on loss temperature rise parameters includes: the winding loss is k 2n-3 times that of the original model, and the core loss is k (n-2)β times that of the original model, where β is the magnetic flux density exponent and n is the scale-down power coefficient.

[0152] In some embodiments, the electromagnetic field parameters include: current, voltage, resistance, leakage magnetic induction, conductance, capacitance, magnetic flux density, current density, and magnetic field strength.

[0153] In some embodiments, after scaling down: the current is k times that of the original model n-1 times, the voltage is k times that of the original model n times, the resistance is k times that of the original model -1 times, the leakage inductance is k times that of the original model, the conductance is k times that of the original model, the capacitance is k times that of the original model, the magnetic flux density is k times that of the original model n-2 times, the current density is k times that of the original model n-3 times, the magnetic field strength is k times that of the original model n-2 times.

[0154] In some embodiments, the physical dimensions include length and area.

[0155] In some embodiments, after scaling down: the length is k times that of the original model, and the area is k 2 times.

[0156] Embodiment III

[0157] This embodiment provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the steps in the method for designing a scaled-down model of a high-power high-frequency transformer based on the principle of frequency invariance as described in Embodiment I above.

[0158] Embodiment IV

[0159] This embodiment provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the steps in the method for designing a scaled-down model of a high-power high-frequency transformer based on the principle of frequency invariance as described in Embodiment I above.

[0160] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of an embodiment implemented in hardware, a software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories and optical memories, etc.) containing computer-usable program code.

[0161] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A design method for a scaled-down model of a high-power high-frequency transformer based on the principle of frequency invariance, characterized in that Including: Perform equal-proportion scaling on the physical dimensions of the original model to determine the geometric scaling factor between the scaled model and the original model; Based on the geometric scaling factor, deduce the scaling relationship of electromagnetic field parameters and calculate the electromagnetic field parameters of the scaled model; Based on the scaling criterion of loss-temperature rise parameters, calculate the winding loss and core loss of the scaled model. The method includes: adjusting the core loss through the Steinmetz formula and calculating the winding loss using the modified Dowell model processed by FFT to ensure that the temperature rise of the scaled model is consistent with that of the original model; the scaling criterion based on loss-temperature rise parameters includes: the winding loss is k 2n -3 times that of the original model, and the core loss is k (n-2)β times that of the original model, where β is the magnetic flux density exponent and n is the scaling power coefficient; Construct a three-dimensional multi-physics coupling model of a high-frequency transformer based on a finite element simulation platform, and perform similarity processing on the three-dimensional multi-physics coupling model of the high-frequency transformer to obtain a scaled model; Perform multi-field coupling simulation analysis on the scaled model to verify and optimize the electromagnetic and loss body characteristics of the scaled model.

2. The design method of the scaled-down model of the high-power high-frequency transformer based on the frequency-invariant principle according to claim 1, wherein, The electromagnetic field parameters include: current, voltage, resistance, leakage magnetic induction, conductance, capacitance, magnetic flux density, current density, and magnetic field strength.

3. The design method of the scaled-down model of the high-power high-frequency transformer based on the frequency-invariant principle according to claim 2, characterized in that After scaling down: The current is k n-1 times that of the original model, the voltage is k n times that of the original model, the resistance is k -1 times that of the original model, the leakage inductance is k times that of the original model, the conductance is k times that of the original model, the capacitance is k times that of the original model, the magnetic flux density is k n-2 times that of the original model, the current density is k n-3 times that of the original model, the magnetic field intensity is k n-2 times.

4. The design method of the scaled-down model of the high-power high-frequency transformer based on the frequency-invariant principle according to claim 1, characterized in that The physical dimensions include length and area.

5. The design method of a scaled-down model of a high-power high-frequency transformer based on the frequency-invariant principle according to claim 4, characterized in that After scaling down: the length is k times that of the original model, and the area is k 2 times that of the original model.

6. A design system for a scaled-down model of a high-power high-frequency transformer based on the principle of frequency invariance, characterized in that, Including: A geometric scaling module configured to perform equal-proportion scaling on the physical dimensions of the original model to determine the geometric scaling factor between the scaled model and the original model; An electromagnetic field scaling module configured to deduce the scaling relationship of electromagnetic field parameters based on the geometric scaling factor and calculate the electromagnetic field parameters of the scaled model; Loss reduction ratio module, which is configured to: calculate the winding loss and core loss of the reduced-scale model based on the reduction ratio criterion of the loss temperature rise parameter. The method includes: adjusting the core loss through the Steinmetz formula and calculating the winding loss by using the corrected Dowell model processed by FFT to ensure that the temperature rise of the reduced-scale model is consistent with that of the original model; the reduction ratio criterion based on the loss temperature rise parameter includes: the winding loss is k 2n-3 times that of the original model, and the core loss is k (n-2)β times that of the original model, where β is the magnetic flux density index and n is the reduction ratio power coefficient; A model construction module configured to construct a three-dimensional multi-physics coupling model of a high-frequency transformer based on a finite element simulation platform and perform similarity processing on the three-dimensional multi-physics coupling model of the high-frequency transformer to obtain a scaled model; A simulation optimization module configured to perform multi-field coupling simulation analysis on the scaled model to verify and optimize the electromagnetic and loss body characteristics of the scaled model.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by a processor, it implements the steps in the design method of the scaled model of a high-power high-frequency transformer based on the frequency invariance principle as described in any one of claims 1-5.

8. A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the design method of the scaled model of a high-power high-frequency transformer based on the frequency invariance principle as described in any one of claims 1-5.

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