Method for obtaining magnetic field strength in high-frequency transformer winding

Abstract

This invention discloses a method for obtaining the magnetic field strength in the windings of a high-frequency transformer. The high-frequency transformer includes a magnetic core, multiple layers of windings with gradually increasing distances from the magnetic core, and an insulating layer located between adjacent windings. The method includes: S1, obtaining the magnetic field strength of the p-th layer winding in the frequency domain when an input AC current is applied; S2, converting the magnetic field strength of the p-th layer winding in the frequency domain into the magnetic field strength of the p-th layer winding in the time domain; S3, obtaining the effective value of the magnetic field strength based on the magnetic field strength of the p-th layer winding in the time domain. This invention can convert the magnetic field strength of the winding in the frequency domain into the magnetic field strength in the time domain, and thus obtain the effective value of the magnetic field strength. The magnitude of the magnetic field strength in the time domain changes with t, but its effective value is independent of time. The effective value of the magnetic field strength can reflect the overall performance of the periodically changing magnetic field strength, thereby laying the foundation and providing convenience for the later application of high-frequency transformers.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic power, and particularly relates to a method for obtaining magnetic field intensity in a high-frequency transformer winding. BACKGROUND

[0002] Switching power converter works in high-frequency state to reduce the volume and weight of the entire power electronic system, and the high-frequency transformer is a most commonly used element in the switching power converter.

[0003] Referring to Figure 1 Fig. 1 shows a structure diagram of a half high-frequency transformer winding in a ZX plane of the prior art, which comprises a magnetic core 10, a plurality of layers of windings 20 gradually increasing in distance from the magnetic core, and an insulating layer 30 between adjacent windings, the winding is a copper foil winding, and comprises a plurality of primary windings 21 and a plurality of secondary windings 22. Figure 1 For the structure in Fig. 1, Ouyang ziwei et al. reported a calculation method of the magnetic field intensity in the high-frequency transformer winding in 2015, and the magnetic field intensity is:

[0004]

[0005] wherein, the magnetic field intensity of the right boundary of the first layer of windings, I is the input current of the winding, bf is the height of the winding, n is the number of layers in the primary winding, is the complex propagation constant, μ0 is the magnetic permeability in vacuum, σ is the electrical conductivity of the winding, ω is the angular frequency, and t is the thickness of the winding.

[0006] When the structural parameters of the designed transformer are known, the designer can calculate the magnetic field intensity distribution in the winding according to formula (1).

[0007] However, for the determination of the magnetic field intensity in the high-frequency transformer winding, the above scheme only gives the expression of the magnetic field intensity in the frequency domain, and the effective value of the magnetic field intensity cannot be directly obtained according to the expression of the magnetic field intensity in the frequency domain, which brings practical difficulties to the application, such as the research on the leakage inductance in the high-frequency transformer.

[0008] Therefore, in view of the above technical problems, it is necessary to provide a method for obtaining the magnetic field intensity in the high-frequency transformer winding. SUMMARY

[0009] Therefore, in view of the above technical problems, it is necessary to provide a method for obtaining the magnetic field intensity in the high-frequency transformer winding.

[0010] In order to achieve the above-mentioned purpose, the technical scheme provided by an embodiment of the application is as follows:

[0011] A method for obtaining the magnetic field strength in a high-frequency transformer winding, the high-frequency transformer comprising a magnetic core, multi-layer windings with gradually increasing distance from the magnetic core, and an insulating layer located between adjacent windings, the method comprising:

[0012] S1. Obtain the magnetic field strength of the p-th winding of the high-frequency transformer in the frequency domain when the input AC current is applied.

[0013] S2. Convert the magnetic field strength of the p-th layer winding in the frequency domain into the magnetic field strength of the p-th layer winding in the time domain;

[0014] S3. Obtain the effective value of the magnetic field strength based on the magnetic field strength of the p-th layer winding in the time domain.

[0015] In one embodiment, in step S1, the magnetic field strength of the p-th winding of the high-frequency transformer in the frequency domain is... for:

[0016]

[0017] in, b is the magnetic field strength at the boundary of the first winding away from the core. f where h is the winding height and h is the winding thickness. Input AC current to the winding The vector form, where α is the complex propagation constant, satisfies δ wf To reach skin depth and meet ω is the angular frequency, satisfying ω=2πf, f is the frequency of the alternating current, μ0 is the permeability in vacuum, σ is the conductivity of the winding, j is the unit of the imaginary number in the complex number, and x is the coordinate of the horizontal axis x in the p-th layer of winding. The x-axis extends to the right of the p-th layer of winding with the leftmost edge of the p-th layer of winding as the origin of the coordinate system until the rightmost edge.

[0018] In one embodiment, the input AC current is a sinusoidal current or the sum of multiple sinusoidal currents.

[0019] In one embodiment, step S2 specifically includes:

[0020] Based on the magnetic field strength of the p-th layer winding in the frequency domain The mode for obtaining magnetic field strength And complex angle φ1;

[0021] The magnetic field strength of the p-th layer winding in phasor form in the frequency domain Converted to the magnetic field strength H of the p-th layer winding in the time domain Z (t,x).

[0022] In one embodiment, the magnetic field strength of the p-th layer winding in phasor form in the frequency domain is:

[0023]

[0024] in:

[0025]

[0026]

[0027] φ represents the initial phase of the input alternating current, and φ+φ1 represents the magnetic field strength. The first appearance.

[0028] In one embodiment, the magnitude of the magnetic field strength The complex angle φ1 and the complex angle φ1 are respectively:

[0029]

[0030]

[0031] In one embodiment, the magnetic field strength H of the p-th layer winding in the time domain is... Z (t,x) is:

[0032]

[0033] In one embodiment, the effective value H of the magnetic field strength of the p-th layer winding in the time domain is... Z (RMS) is the modulus of the magnetic field strength. Right now:

[0034]

[0035] The present invention has the following beneficial effects:

[0036] This invention can convert the magnetic field strength of the winding in the frequency domain into the magnetic field strength in the time domain, thereby obtaining the effective value of the magnetic field strength. The magnitude of the magnetic field strength in the time domain changes with t, but its effective value is independent of time. The effective value of the magnetic field strength can reflect the overall performance of the periodically changing magnetic field strength, thus laying the foundation and providing convenience for the later application of high-frequency transformers. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the structure of half a high-frequency transformer winding in the ZX plane;

[0039] Figure 2 This is a schematic flowchart of the method for obtaining the magnetic field strength in the winding of the high-frequency transformer of the present invention. Specific embodiments

[0040] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0041] Refer Figure 2 As shown, the present invention discloses a method for obtaining the magnetic field strength in the winding of a high-frequency transformer. The structure of the high-frequency transformer is referred Figure 1 As shown, it includes a magnetic core, multiple layers of windings with gradually increasing distances from the magnetic core, and insulating layers located between adjacent windings. The method for obtaining the magnetic field strength includes:

[0042] S1. Obtain the magnetic field strength of the p-th layer winding of the high-frequency transformer in the frequency domain when an input alternating current is applied;

[0043] S2. Convert the magnetic field strength of the p-th layer winding in the frequency domain into the magnetic field strength of the p-th layer winding in the time domain;

[0044] S3. Obtain the effective value of the magnetic field strength according to the magnetic field strength of the p-th layer winding in the time domain.

[0045] Among them, step S2 is specifically:

[0046] According to the magnetic field strength of the p-th layer winding in the frequency domain Obtain the modulus of the magnetic field strength and the complex angle φ1;

[0047] Convert the magnetic field strength in phasor form of the p-th layer winding in the frequency domain into the magnetic field strength H Z (t, x) of the p-th layer winding in the time domain.

[0048] Figure 1 As shown, it is a schematic structural diagram of half of the winding of a high-frequency transformer in the ZX plane of the prior art. Specifically, in this embodiment, the winding is described by taking 3 primary windings and 2 secondary windings as an example. Preferably, the winding adopts a copper foil winding.

[0049] The current direction in the primary winding is the negative Y direction. Therefore, the electric field strength in the primary winding can be expressed as The magnetic field generated in the primary winding is in the Z direction; therefore, the magnetic field strength in the primary winding can be expressed as: The magnetic field strength of the p-th winding in the frequency domain can be obtained using conventional analysis methods. for:

[0050]

[0051] in, b is the magnetic field strength at the boundary of the first winding away from the core. f where h is the winding height and h is the winding thickness. Input AC current to the winding The vector form, where α is the complex propagation constant, satisfies δ wf To reach skin depth and meet ω is the angular frequency, satisfying ω=2πf, f is the frequency of the alternating current, μ0 is the permeability in vacuum, σ is the conductivity of the winding, j is the unit of the imaginary number in the complex number, and x is the coordinate of the horizontal axis x in the p-th layer of winding. The x-axis extends to the right of the p-th layer of winding with the leftmost edge of the p-th layer of winding as the origin of the coordinate system until the rightmost edge.

[0052] Since the current flowing through the windings of the high-frequency transformer is alternating current, the magnetic field excited by this current also varies with time. With each periodic change of the power supply, magnetic field energy is alternately stored and released. The above equation represents the magnetic field strength in the frequency domain. To find its modulus and complex angle, it is expanded using a Taylor series.

[0053] According to the Taylor series of hyperbolic functions, sinh(αx) can be expanded as:

[0054]

[0055] Substituting the magnetic field strength in the frequency domain In the formula, the magnetic field strength It can be expanded and represented in complex form, specifically:

[0056]

[0057] In this context, the input current of the transformer's primary winding is assumed to be a sine wave, i.e. The phasor representation of this input current is as follows: If the input current is non-sinusoidal, it can be decomposed into a sum of multiple sine waves using Fourier decomposition, where φ is the initial phase of the input AC current.

[0058] make:

[0059]

[0060] The magnetic field strength of the p-th layer winding in phasor form in the frequency domain is:

[0061]

[0062] Where φ is the initial phase of the input AC current, and φ+φ1 is the magnetic field strength. The first appearance.

[0063] Magnetic field strength modulus The complex angle φ1 and the complex angle φ1 are respectively:

[0064]

[0065]

[0066] The magnetic field strength of the p-th layer winding in phasor form in the frequency domain Converted to the magnetic field strength H of the p-th layer winding in the time domain Z (t,x). Specifically:

[0067]

[0068] According to the magnetic field strength H in the time domain Z The effective value H of the magnetic field strength can be obtained by finding the expression for (t,x). Z (RMS), H Z (RMS) is the modulus of the magnetic field strength. Right now:

[0069]

[0070] As can be seen from the above technical solutions, the present invention has the following advantages:

[0071] This invention can convert the magnetic field strength of the winding in the frequency domain into the magnetic field strength in the time domain, thereby obtaining the effective value of the magnetic field strength. The magnitude of the magnetic field strength in the time domain changes with t, but its effective value is independent of time. The effective value of the magnetic field strength can reflect the overall performance of the periodically changing magnetic field strength, thus laying the foundation and providing convenience for the later application of high-frequency transformers.

[0072] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0073] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for obtaining the magnetic field strength in a high-frequency transformer winding, the high-frequency transformer comprising a magnetic core, multiple layers of windings with gradually increasing distance from the magnetic core, and an insulating layer located between adjacent windings, characterized in that, The method includes: S1, when obtaining the input AC current, the high-frequency transformer... p The magnetic field strength of the layered winding in the frequency domain; S2, the first p The magnetic field strength of the layer winding in the frequency domain is converted into the first p The magnetic field strength of the layered winding in the time domain; S3, according to the first p The effective value of the magnetic field strength in the time domain of the layered winding is obtained; In step S1, the high-frequency transformer... p Magnetic field strength of layered windings in the frequency domain for: ； in, The magnetic field strength at the boundary of the first winding away from the core. For winding height, For winding thickness, Input AC current to the winding The vector form, Let be the complex propagation constant, satisfying , To reach skin depth and meet , Let be the angular frequency, satisfying , The frequency of alternating current, Permeability in vacuum The conductivity of the winding, j It is the unit of the imaginary number in complex numbers. x It is the first p Horizontal axis in layer winding x The coordinates of the first p The leftmost edge of the layer winding is the origin of the coordinate system. x Axial first p The layer winding extends to the rightmost edge.

2. The method for obtaining the magnetic field strength in the winding of a high-frequency transformer according to claim 1, characterized in that, The input AC current is a sinusoidal current or the sum of multiple sinusoidal currents.

3. The method for obtaining the magnetic field strength in the winding of a high-frequency transformer according to claim 1, characterized in that, Step S2 specifically involves: According to the p Magnetic field strength of layered windings in the frequency domain The mode for obtaining magnetic field strength and complex angles ; The first p Magnetic field strength in phasor form of layered windings in the frequency domain Transform into the first p Magnetic field strength of layer winding in time domain .

4. The method for obtaining the magnetic field strength in the winding of a high-frequency transformer according to claim 3, characterized in that, The first p The magnetic field strength of the layered winding in phasor form in the frequency domain is: ； in: ； ； The initial phase of the input alternating current. magnetic field strength The first appearance.

5. The method for obtaining the magnetic field strength in the winding of a high-frequency transformer according to claim 4, characterized in that, The magnitude of the magnetic field strength and complex angles They are respectively: ； 。 6. The method for obtaining the magnetic field strength in the winding of a high-frequency transformer according to claim 4, characterized in that, The first p Magnetic field strength of layer winding in time domain for: 。 7. The method for obtaining the magnetic field strength in the winding of a high-frequency transformer according to claim 5, characterized in that, The first p Effective value of magnetic field strength of layer winding in time domain The modulus of magnetic field strength ,Right now: 。

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