High-frequency transformer winding loss calculation method based on finite element and eddy current loss characteristics

Abstract

The invention discloses a high-frequency transformer winding loss calculation method based on finite element and eddy current loss characteristics, and the method comprises the following steps: 1, building a model of a Helmholtz coil and a single winding through finite element software, and simulating an alternating magnetic field in a high-frequency transformer through the Helmholtz coil; 2, changing the magnetic field frequency, and recording the eddy current loss of a single winding of the high-frequency transformer at different frequencies of a Helmholtz coil; step 3, an eddy-current loss correction factor between different frequencies is calculated by using an eddy-current loss characteristic formula; 4, the eddy-current loss generated in the high-frequency transformer winding is calculated by using the eddy-current loss factor, and comparison verification is carried out by using a traditional formula method; 5, adding the eddy current loss to the direct current loss of the high-frequency transformer winding to obtain the total winding loss of the high-frequency transformer; the method solves the problem that a common eddy current factor method is not high in calculation precision.

Description

Technical Field

[0001] This invention relates to the field of high-frequency transformer technology, and in particular to a method for calculating the winding losses of high-frequency transformers based on finite element analysis and eddy current loss characteristics. Background Technology

[0002] As a key component of power electronic transformers, high-frequency transformers not only perform functions such as power transmission, voltage transformation, and electrical isolation, but their efficiency and heat generation directly affect the performance of power electronic transformers. Current power electronics technology is trending towards higher frequencies. While higher-frequency transformers can effectively reduce size and increase power density, they also bring problems such as increased loss density and difficulty in controlling temperature rise, increasing the complexity of high-frequency transformer design. Therefore, accurate calculation of winding losses in high-frequency transformers is of great research significance.

[0003] Traditional methods for calculating high-frequency transformer winding losses include the formula method and the finite element method (FEM). While the formula method is faster, its derivation often requires many idealized assumptions to simplify the formula, which typically leads to larger errors in the results. Generally, the formula needs to be modified according to the specific circumstances to obtain more accurate results with smaller errors. In contrast, the finite element method has much wider applicability, and its results for calculating high-frequency transformer winding losses are also very accurate. However, the longer computation time required for finite element calculations is a significant drawback.

[0004] Currently, there are many mature formulaic methods for calculating the winding losses of high-frequency transformers, such as the Dowell formula and the Ferreira formula, as well as various improved formulas based on these two. However, these formulas can only be applied to one or a few specific winding forms and shapes, which limits the applicability of the formulaic methods. When calculating the winding losses of high-frequency transformers using the finite element method, the winding structure is often simplified to improve computer computing efficiency, which to some extent affects the accuracy of the calculation results. If simplification is not performed, the high-precision finite element model requires a large amount of computer resources, which is not conducive to the widespread adoption of this method. Using eddy current loss characteristics to calculate winding losses is applicable to windings of various shapes and can achieve good calculation accuracy. However, in the specific derivation of the eddy current loss factor, the treatment of the magnetic field is relatively ideal, which can lead to a certain degree of error. Moreover, the proximity effect between windings in the same layer is not considered. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a method for calculating the winding loss of high-frequency transformers based on finite element method and eddy current loss characteristics. By using the eddy current loss factor to calculate the winding loss of high-frequency transformers, the problem of the limited applicability of the formula method is solved. At the same time, the finite element modeling method is used to obtain the winding eddy current loss factor between different frequencies, thus solving the problem of low calculation accuracy of the ordinary eddy current factor method.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this invention is: a high-frequency transformer winding loss calculation method based on finite element method and eddy current loss characteristics, comprising the following steps: Step 1: Use finite element software to build models of Helmholtz coils and single windings, and use Helmholtz coils to simulate the alternating magnetic field in a high-frequency transformer; Step 2: Change the magnetic field frequency and record the eddy current loss of a single winding of the high-frequency transformer at different frequencies of the Helmholtz coil. Step 3: Calculate the eddy current loss correction factor for different frequencies using the eddy current loss characteristic formula; Step 4: Calculate the eddy current loss generated in the high-frequency transformer winding using the eddy current loss factor, and verify it by comparison using the traditional formula method. Step 5: Add the eddy current loss to the DC loss of the high-frequency transformer winding to obtain the total winding loss of the high-frequency transformer.

[0007] Preferably, in step 2, recording the eddy current losses of a single winding of the high-frequency transformer at different frequencies using the Helmholtz coil includes: Step 2.1: Place a single winding conductor of the target high-frequency transformer at the center of the Helmholtz coil; Step 2.2: Change the frequency of the high-frequency current in the Helmholtz coil; Step 2.3: Record the eddy current losses generated in a single winding conductor under different harmonics.

[0008] Preferably, in step 3, the eddy current loss characteristic formula includes: Step 3.1: The relationship between eddy current losses at different frequencies can be expressed as follows: (1); in, This refers to the eddy current loss of the transformer winding at the fundamental frequency. It refers to the eddy current loss of the winding at high frequencies. It is the magnitude of the fundamental frequency current. It refers to the magnitude of the high-frequency current. It is the fundamental frequency. It is a high frequency. It is a correction factor; Step 3.2: Change the frequency of the current in the Helmholtz coil, but do not change the magnitude of the current. ; Step 3.3, will Substituting into equation (1), the correction factors for conductor eddy current losses at different frequencies are shown in equation (2): (2); In equation (2) This represents the eddy current loss of a single winding of a transformer at the fundamental frequency. This indicates the eddy current loss of a single winding at high frequencies.

[0009] Preferably, in step 4, calculating the eddy current losses generated in the high-frequency transformer windings includes: Substituting the eddy current effect correction factor calculated in step 3 into equation (1) will determine the eddy current losses of all windings of the transformer. The total loss of a transformer winding is the sum of the DC resistance loss and the eddy current loss of the transformer winding. Finite element modeling can enhance the accuracy of the correction factor, thereby improving the accuracy of the final winding loss.

[0010] Preferably, in step 4, the comparative verification using the traditional formula method includes: For small-capacity high-frequency transformers using circular and rectangular windings, there are three formulas for calculating winding losses: the Dowell formula, the modified Dowell formula, and the modified Ferreira formula. The Dowell formula is used for rectangular windings, while the modified Dowell formula and the modified Ferreira formula are used for circular windings. These formulas can all demonstrate that the winding losses of high-frequency transformers are affected by factors such as frequency, the number of winding layers, and material properties.

[0011] Preferably, the Dowell formula specifically includes: Dowell first analyzed the magnetic field inside the transformer window of the copper foil winding and proposed two assumptions: First, the core window is completely filled vertically by copper foil, and the distance between adjacent copper foils is very close. According to Ampere's circuital law, there is only a vertical magnetic field strength inside the core window. Second, the magnetic permeability of the core material is infinite, and the magnetomotive force is completely applied inside the core window. Based on the above assumptions, formula (3) is derived: (3); in:

[0012] In the formula Permeability, For electrical conductivity, For deep skin care, For conductor transmittance, For the thickness of the winding, This refers to the number of winding layers. For the current frequency, For the AC resistance of the winding, The DC resistance of the winding, is the AC resistivity.

[0013] Preferably, the improved Dowell formula specifically includes: For circular conductors, each circular conductor can be equivalent to a square conductor with the same cross-sectional area. Then, the same layer of square conductors can be further equivalent to conductors with a height of... h w The copper foil; because the magnetic field around the conductor changes before and after the equivalent, the conductivity and transmittance need to be adjusted and compensated, as shown in the corrected formula below: (4); In the formula It is the diameter of the round conductor. It is the side length of the equivalent square conductor. It is the height of the core window. It is the winding fill factor. It is the number of windings per layer. It is the number of winding layers. It is the conductor transmittance after compensation.

[0014] Preferably, the improved Ferreira formula includes: Based on the orthogonality of the skin effect and proximity effect in a circular conductor, the Ferreira formula can be derived, and its expression is shown in (5): (5); Based on this, the improved Ferreira formula is obtained by modifying the formula using the winding fill ratio, as shown in equation (6): (6); in It is the real part of the first kind of Bessel function. It is the imaginary part of the first kind of Bessel function. It is the real part of the second-order Bessel function. It is the imaginary part of the second-order Bessel function. It is the distance between the centers of two adjacent circular conductors. It is the conductor transmittance after the Ferreira formula is corrected; the expression for the Bessel function is shown in equation (7), where It is the order of the Bessel function. It is an imaginary number. For Bessel functions: (7).

[0015] Preferably, in step 5, the eddy current loss is added to the DC loss of the high-frequency transformer winding to obtain the total winding loss of the high-frequency transformer, which includes: For total winding loss Its analytical expression is: (8); In the formula This is the effective value of the current flowing through the winding. This is the DC resistance value of the winding. This refers to the winding eddy current loss calculated in step 4.

[0016] Preferably, step 1 specifically includes the following process: To simulate a Helmholtz coil using COMSOL finite element software, first, a geometric model is established, including the geometry of the air and the coil. Then, relevant material parameters are added to the geometric model. Finally, relevant physical fields are added to the model, and simulation parameters are set in the physical fields.

[0017] Beneficial effects of this invention: 1) This invention uses the finite element method to obtain the eddy current loss factor of the winding conductor of the high-frequency transformer, then uses the eddy current loss characteristic formula to calculate the total eddy current loss of the high-frequency transformer winding, and finally adds it to the DC resistance loss to obtain the total winding loss. The obtained winding loss calculation result has extremely high accuracy.

[0018] 2) This invention optimizes the traditional finite element method modeling method, which requires a large amount of computer resources. The high-frequency transformer winding loss calculation method based on finite element and eddy current loss characteristics can reduce the computer resources consumed by more than two-thirds, thus saving a lot of calculation time.

[0019] 3) The high-frequency transformer winding loss calculation method based on finite element and eddy current loss characteristics proposed in this invention has a low calculation accuracy affected by winding shape and winding structure, and has good versatility and practicality.

[0020] 4) This invention solves the problem of the limited applicability of the formula method by using the eddy current loss factor to calculate the winding loss of high-frequency transformers. At the same time, it uses the finite element modeling method to obtain the winding eddy current loss factor between different frequencies, thus solving the problem of low calculation accuracy of the ordinary eddy current factor method. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the process of the present invention; Figure 2This is a schematic diagram of the finite element model of a Helmholtz coil as an example. Figure 3 The figure shows the eddy current test results of a single winding conductor in a Helmholtz coil as an example. Figure 4 This is a schematic diagram of a high-frequency transformer model for an embodiment. Figure 5 This is a comparison chart showing the calculation results of the total winding loss of a high-frequency transformer under different methods, as an example. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0023] Example: Combined with Appendix Figure 1 A method for calculating the winding loss of a high-frequency transformer based on finite element method and eddy current loss characteristics includes the following steps.

[0024] Step 1: Use finite element software to build models of Helmholtz coils and single windings, and use the Helmholtz coils to simulate the alternating magnetic field in a high-frequency transformer; A Helmholtz coil typically consists of two coils of the same size and number of turns with their axes aligned. The distance between these two coils is usually 0.5 to 1.5 times the coil radius. This symmetrical arrangement of the coils results in a relatively uniform distribution of the magnetic field in the space between the two coils, which can well simulate the alternating magnetic field around the windings in a high-frequency transformer.

[0025] To simulate a Helmholtz coil using COMSOL finite element software, first, a geometric model is established, including the geometry of the air and the coil. Then, relevant material parameters, such as electrical conductivity and magnetic permeability, are added to the geometric model. Finally, relevant physical fields are added to the model, and simulation parameters are set within these fields. Figure 2 As shown, it includes a set of Helmholtz coil models with a radius of R=50mm, with an amplitude of 200A injected into the upper and lower coils at a frequency of [missing value]. A sinusoidal current.

[0026] Step 2: Change the magnetic field frequency and record the eddy current loss of a single winding of the high-frequency transformer at different frequencies in the Helmholtz coil. A rectangular copper wire 1 mm wide and 5 mm high, and a circular copper wire 1 mm in diameter are placed at the center of the uniform magnetic field formed by a Helmholtz coil. Influenced by the surrounding alternating magnetic field, eddy currents are generated inside the wires, leading to eddy current losses within the conductors. The total eddy current loss generated by a single winding at the operating frequency is calculated using finite element software. The frequency of the sinusoidal excitation current in the coil is then gradually increased to 20 kHz, and the eddy current loss generated at each frequency is recorded. The recorded eddy current losses generated by a single wire are shown below. Figure 3As shown, with increasing frequency of the alternating magnetic field, the eddy current losses generated in a single winding also increase, and generally, the eddy current losses show a trend of being proportional to the square of the frequency. Furthermore, the Helmholtz coil is an open-circuit magnetic circuit system, and its magnetic field distribution effectively satisfies the principle of linear superposition.

[0027] Step 3: Calculate the eddy current loss correction factor for different frequencies using the eddy current loss characteristic formula; 1) The relationship between eddy current losses at different frequencies can be expressed as: (1) in This refers to the eddy current loss of the transformer winding at the fundamental frequency. It refers to the eddy current loss of the winding at high frequencies. It is the magnitude of the fundamental frequency current. It refers to the magnitude of the high-frequency current. It is the fundamental frequency. It is a high frequency. It is a correction factor.

[0028] 2) Change the frequency of the current in the Helmholtz coil, but do not change the magnitude of the current, i.e. A Helmholtz coil is an open-circuit magnetic circuit system, and its magnetic field distribution can well satisfy the principle of linear superposition.

[0029] 3) Substituting into equation (1), the correction factors for conductor eddy current losses at different frequencies are shown in equation (2). Note that in equation (2) and This represents the eddy current loss of a single winding, not the eddy current loss of all windings of the transformer in equation (1).

[0030] (2) Step 4: Calculate the eddy current losses generated in the high-frequency transformer windings using the eddy current loss factor. Substituting the eddy current effect correction factor calculated in step three into equation (1) will determine the eddy current losses of all windings of the transformer. The total loss of the transformer winding is the sum of the DC resistance loss and the eddy current loss of the transformer winding. ),use Figure 4 Taking the two winding shapes shown as examples of high-frequency transformers: When the winding shape is as follows Figure 4 When the rectangle shown in (a) is a rectangle, it can be used Figure 3The eddy current loss characteristics of a single rectangular conductor of the same specification can be substituted into equation (2) to obtain the eddy current loss factor of the rectangular winding. Then, by substituting the eddy current loss of the rectangular winding high-frequency transformer into equation (1), the winding eddy current loss of the transformer can be obtained.

[0031] When the winding shape is as follows Figure 4 When the diagram in (b) is circular, it can be used... Figure 3 The eddy current loss characteristics of a single circular conductor of the same specification can be substituted into equation (2) to obtain the eddy current loss factor of the circular winding. Then, by substituting the eddy current loss of the circular winding high-frequency transformer into equation (1), the winding eddy current loss of the circular winding high-frequency transformer can be obtained.

[0032] Then, the Dowell formula is used to calculate the winding loss of the rectangular winding, and the modified Dowell formula and the modified Ferreira formula are used to calculate the winding loss of the circular winding.

[0033] 1)Dowell’s formula: Dowell first analyzed the magnetic field inside the transformer window of the copper foil winding and proposed two assumptions: First, the core window is vertically completely filled with copper foil, and the distance between adjacent copper foils is very close. According to Ampere's circuital law, there is only a vertical magnetic field strength inside the core window. Second, the magnetic permeability of the core material is assumed to be infinite, and the magnetomotive force is completely applied inside the core window. Based on the above assumptions, formula (3) is derived: (3) in

[0034] In the formula Permeability, For electrical conductivity, For deep skin care, For conductor transmittance, For the thickness of the winding, This refers to the number of winding layers.

[0035] 2) Improved Dowell formula: For circular conductors, each circular conductor can be equivalent to a square conductor with the same cross-sectional area. Then, the same layer of square conductors can be further equivalent to conductors with a height of... h w The copper foil. Because the magnetic field around the conductor changes before and after the equivalent, the conductivity and transmittance need to be adjusted and compensated. This is the corrected formula.

[0036] (4) In the formula It is the diameter of the round conductor. It is the side length of the equivalent square conductor. It is the height of the core window. It is the winding fill factor. It is the number of windings per layer. It refers to the number of layers in the winding.

[0037] 3) Improved Ferreira formula: Based on the orthogonality of the skin effect and proximity effect in a circular conductor, the Ferreira formula can be derived, and its expression is shown in (5): (5) Based on this, the improved Ferreira formula is obtained by modifying the formula using the winding fill rate, as shown in equation (6).

[0038] (6) in It is the real part of the first kind of Bessel function. It is the imaginary part of the first kind of Bessel function. It is the real part of the second-order Bessel function. It is the imaginary part of the second-order Bessel function. It is the distance between the centers of two adjacent circular conductors. It is the conductor transmittance after the Ferreira formula is corrected; the expression for the Bessel function is shown in equation (7), where It is the order of the Bessel function. It is an imaginary number. For Bessel functions: (7) Step 5: Add the eddy current loss to the DC loss of the high-frequency transformer winding to obtain the total winding loss of the high-frequency transformer. For total winding loss Its analytical expression is: (8) In the formula This is the effective value of the current flowing through the winding. This is the DC resistance value of the winding. This refers to the winding eddy current loss calculated in step 4.

[0039] When the winding shape is as follows Figure 4 When (a) shows a rectangular winding, the calculated total winding loss of the high-frequency transformer with rectangular windings is as follows: Figure 5 The curve for the mixed method is shown in (a).

[0040] When the winding shape is as follows Figure 4When the diagram in (a) shows a circular winding, the total winding loss of the circular winding high-frequency transformer is calculated under different winding layers (m). Figure 5 The curves for the mixed method are shown in (b), (c) and (d).

[0041] Figure 5 The calculation results of the AC resistance coefficient of the rectangular winding show that the hybrid method can be used to calculate the winding loss of high-frequency transformers. Figure 5 The calculation results for the AC resistivity of circular windings show that the hybrid method can achieve good calculation accuracy without requiring correction based on the winding shape. Finally, a comparison... Figure 5 China and other countries The calculation results of the AC resistance coefficient under the value and cross-transformed winding structure show that, compared with the traditional formula method, the calculation accuracy of the hybrid method is less affected by the winding structure.

[0042] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A method for calculating the winding losses of high-frequency transformers based on finite element method and eddy current loss characteristics, characterized in that, Includes the following steps: Step 1: Use finite element software to build models of Helmholtz coils and single windings, and use Helmholtz coils to simulate the alternating magnetic field in a high-frequency transformer; Step 2: Change the magnetic field frequency and record the eddy current loss of a single winding of the high-frequency transformer at different frequencies of the Helmholtz coil. Step 3: Calculate the eddy current loss correction factor for different frequencies using the eddy current loss characteristic formula; Step 4: Calculate the eddy current loss generated in the high-frequency transformer winding using the eddy current loss factor, and verify it by comparison using the traditional formula method. Step 5: Add the eddy current loss to the DC loss of the high-frequency transformer winding to obtain the total winding loss of the high-frequency transformer.

2. The method for calculating high-frequency transformer winding losses based on finite element method and eddy current loss characteristics according to claim 1, characterized in that, In step 2, the eddy current losses of a single winding of the high-frequency transformer at different frequencies in the Helmholtz coil are recorded, including: Step 2.1: Place a single winding conductor of the target high-frequency transformer at the center of the Helmholtz coil; Step 2.2: Change the frequency of the high-frequency current in the Helmholtz coil; Step 2.3: Record the eddy current losses generated in a single winding conductor under different harmonics.

3. The method for calculating high-frequency transformer winding losses based on finite element method and eddy current loss characteristics according to claim 1, characterized in that, Step 3 utilizes the eddy current loss characteristic formula, including: Step 3.1: The relationship between eddy current losses at different frequencies can be expressed as follows: （1）； in, This refers to the eddy current loss of the transformer winding at the fundamental frequency. It refers to the eddy current loss of the winding at high frequencies. It is the magnitude of the fundamental frequency current. It refers to the magnitude of the high-frequency current. It is the fundamental frequency. It is a high frequency. It is a correction factor; Step 3.2: Change the frequency of the current in the Helmholtz coil, but do not change the magnitude of the current. ; Step 3.3, will Substituting into equation (1), the correction factors for conductor eddy current losses at different frequencies are shown in equation (2): （2）； In equation (2) This represents the eddy current loss of a single winding of a transformer at the fundamental frequency. This indicates the eddy current loss of a single winding at high frequencies.

4. The method for calculating high-frequency transformer winding losses based on finite element method and eddy current loss characteristics according to claim 3, characterized in that, Step 4, calculating the eddy current losses generated in the high-frequency transformer windings includes: Substituting the eddy current effect correction factor calculated in step 3 into equation (1) will determine the eddy current losses of all windings of the transformer. The total loss of a transformer winding is the sum of the DC resistance loss and the eddy current loss of the transformer winding. Finite element modeling can enhance the accuracy of the correction factor, thereby improving the accuracy of the final winding loss.

5. The method for calculating high-frequency transformer winding losses based on finite element method and eddy current loss characteristics according to claim 1, characterized in that, Step 4, using the traditional formula method for comparison and verification, includes: For small-capacity high-frequency transformers using circular and rectangular windings, there are three formulas for calculating winding losses: the Dowell formula, the modified Dowell formula, and the modified Ferreira formula. The Dowell formula is used for rectangular windings, while the modified Dowell formula and the modified Ferreira formula are used for circular windings. These formulas can all demonstrate that the winding losses of high-frequency transformers are affected by factors such as frequency, the number of winding layers, and material properties.

6. The method for calculating high-frequency transformer winding losses based on finite element method and eddy current loss characteristics according to claim 5, characterized in that, Dowell's formulas specifically include: Dowell first analyzed the magnetic field inside the transformer window of the copper foil winding and proposed two assumptions: First, the core window is completely filled vertically by copper foil, and the distance between adjacent copper foils is very close. According to Ampere's circuital law, there is only a vertical magnetic field strength inside the core window. Second, the magnetic permeability of the core material is infinite, and the magnetomotive force is completely applied inside the core window. Based on the above assumptions, formula (3) is derived: （3）； in: In the formula Permeability, For electrical conductivity, For deep skin care, For conductor transmittance, For the thickness of the winding, This refers to the number of winding layers. For the current frequency, For the AC resistance of the winding, The DC resistance of the winding, is the AC resistivity.

7. The method for calculating high-frequency transformer winding losses based on finite element method and eddy current loss characteristics according to claim 5, characterized in that, The improvements to Dowell's formula specifically include: For circular conductors, each circular conductor can be equivalent to a square conductor with the same cross-sectional area. Then, the same layer of square conductors can be further equivalent to conductors with a height of... h w The copper foil; because the magnetic field around the conductor changes before and after the equivalent, the conductivity and transmittance need to be adjusted and compensated, as shown in the corrected formula below: （4）； In the formula It is the diameter of the round conductor. It is the side length of the equivalent square conductor. It is the height of the core window. It is the winding fill factor. It is the number of windings per layer. It is the number of winding layers. It is the conductor transmittance after compensation.

8. The method for calculating high-frequency transformer winding losses based on finite element method and eddy current loss characteristics according to claim 5, characterized in that, The improved Ferreira formula includes: Based on the orthogonality of the skin effect and proximity effect in a circular conductor, the Ferreira formula can be derived, and its expression is shown in (5): （5）； Based on this, the improved Ferreira formula is obtained by modifying the formula using the winding fill ratio, as shown in equation (6): （6）； in It is the real part of the first kind of Bessel function. It is the imaginary part of the first kind of Bessel function. It is the real part of the second-order Bessel function. It is the imaginary part of the second-order Bessel function. It is the distance between the centers of two adjacent circular conductors. It is the conductor transmittance after the Ferreira formula is corrected; the expression for the Bessel function is shown in equation (7), where It is the order of the Bessel function. It is an imaginary number. For Bessel functions: （7）。 9. The method for calculating high-frequency transformer winding losses based on finite element method and eddy current loss characteristics according to claim 1, characterized in that, In step 5, the eddy current loss is added to the DC loss of the high-frequency transformer winding to obtain the total winding loss of the high-frequency transformer, which includes: For total winding loss Its analytical expression is: （8）； In the formula This is the effective value of the current flowing through the winding. This is the DC resistance value of the winding. This refers to the winding eddy current loss calculated in step 4.

10. The method for calculating high-frequency transformer winding losses based on finite element method and eddy current loss characteristics according to claim 1, characterized in that, Step 1 is specifically... Includes the following processes: To simulate a Helmholtz coil using COMSOL finite element software, first, a geometric model is established, including the geometry of the air and the coil. Then, relevant material parameters are added to the geometric model. Finally, relevant physical fields are added to the model, and simulation parameters are set in the physical fields.

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