WO2021104424A1

WO2021104424A1 - Ltcc high-voltage transformer

Info

Publication number: WO2021104424A1
Application number: PCT/CN2020/132126
Authority: WO
Inventors: 赵斌; 王刚; 王东蕾; 赵燕
Original assignee: 中国科学院空天信息创新研究院
Priority date: 2019-11-29
Filing date: 2020-11-27
Publication date: 2021-06-03
Also published as: CN110911088B; CN110911088A

Abstract

The present disclosure provides an LTCC high-voltage transformer, comprising: an upper side column, a magnetic core middle column, a lower side column, a primary coil, a secondary coil, first mediums and second mediums, the upper side column, the magnetic core middle column and the lower side column being sequentially provided from top to bottom, the primary coil and the secondary coil being provided on the magnetic core middle column, the plurality of first mediums being uniformly distributed on the magnetic core middle column in a longitudinal direction, and the plurality of second mediums being respectively provided between two adjacent turns of coils. The present disclosure can effectively reduce magnetic flux leakage of a transformer in a horizontal direction and a vertical direction, and achieve the effect of low leakage inductance.

Description

LTCC high voltage transformer

Technical field

The present disclosure relates to the field of power equipment, and in particular to a high-voltage transformer based on Low Temperature Co-firing Ceramics (LTCC).

Background technique

Low Temperature Co-fired Ceramic LTCC technology has been widely used in the field of radio frequency and microwave. In recent years, with the development of high frequency ferrite materials suitable for LTCC technology and switching power supply operating frequency bands, domestic and foreign Both have carried out research on magnetic devices based on the LTCC process. Using the LTCC process, high power density, ultra-thin size magnetic devices can be produced. In addition, the thermal expansion coefficient of the LTCC material is close to that of the semiconductor material, which can realize the three-dimensional integration of the power supply. The LTCC planar high-voltage transformer integrates windings, magnetic cores and lead wires together to form a low-profile SMD packaged device. Therefore, it has the advantages of low cost, low loss, small volume, high reliability, and easy mass production.

However, ordinary high-voltage transformers are assembled by using discrete ferrite cores and organic insulating materials to encapsulate high-voltage cable packages. However, there are still problems such as complex procedures, inability to produce automatically, and high costs; organic materials are contained, which cannot be sealed, are resistant to temperature and humidity; The non-integrated structure, large thermal resistance, low power density and other issues require technical personnel to further develop more suitable solutions.

Summary of the invention

(1) Technical problems to be solved

The present disclosure provides an LTCC high-voltage transformer to at least partially solve the above-mentioned technical problems.

(2) Technical solution

According to one aspect of the present disclosure, there is provided an LTCC high-voltage transformer, which sequentially includes from top to bottom: an upper side column, a magnetic core center column, and a lower side column; further including:

The primary coil and the secondary coil are fired in the central column of the magnetic core;

A plurality of first media are uniformly distributed on the central pillar of the magnetic core along the longitudinal direction;

A plurality of second media are respectively arranged between adjacent two-turn primary coils, two-turn secondary coils, or between the primary coil and the secondary coil.

In some embodiments of the present disclosure, it further includes: a plurality of connecting holes, which are respectively provided on the first medium.

In some embodiments of the present disclosure, the material of the upper side pillar is a high magnetic permeability material, and the magnetic permeability of the high magnetic permeability material is not less than 400.

In some embodiments of the present disclosure, the material of the lower side pillar is a high-permeability material, and the permeability of the high-permeability material is not less than 400.

In some embodiments of the present disclosure, the material of the pillar in the magnetic core is a low-permeability material, and the permeability of the low-permeability material is not greater than 100.

In some embodiments of the present disclosure, the relative permeability of the upper column and the lower column is greater than the relative permeability of the central column of the magnetic core.

In some embodiments of the present disclosure, the adjacent primary coils are filled with a plurality of the second media.

(3) Beneficial effects

It can be seen from the above technical solutions that the LTCC high voltage transformer of the present disclosure has at least one or part of the following beneficial effects:

(1) The present disclosure realizes the requirement for adjusting the magnetizing inductance of the transformer in practical applications through the first medium arranged on the central column of the magnetic core.

(2) Through the application of the second medium between two adjacent turns, the present disclosure effectively reduces the magnetic leakage in the vertical direction and realizes the effect of low leakage inductance.

(3) Through the application of high magnetic permeability materials and low magnetic permeability materials, the present disclosure effectively reduces the magnetic leakage in the horizontal direction of the transformer and realizes the effect of low leakage inductance.

(4) The present disclosure reduces the overlap area between the primary and the secondary by adopting the transformer winding structure, and effectively reduces the parasitic capacitance.

(5) The present disclosure effectively avoids the problem of delamination during the sintering process caused by the introduction of the medium by arranging connecting holes on the central pillar of the magnetic core.

Description of the drawings

FIG. 1 is a schematic structural diagram of an LTCC transformer adopting a transformer winding structure in the prior art.

Fig. 2 is a schematic structural diagram of an LTCC transformer adopting a transformer winding structure in the prior art.

Fig. 3 is a schematic structural diagram of an LTCC transformer adopting a planar transformer winding structure in the prior art.

FIG. 4 is a schematic diagram of the structure of an LTCC high-voltage transformer according to an embodiment of the disclosure.

[Description of the main component symbols of the embodiments of the present disclosure in the drawings]

1-Upper side column; 2- Lower side column; 3- Magnetic core center column; 4- Primary coil; 5- Secondary coil; 6-First medium; 7-Second medium; 8-Connecting hole.

Detailed ways

The present disclosure provides an LTCC high-voltage transformer including an upper side column, a magnetic core center column, a lower side column, a primary coil, a secondary coil, a first medium and a second medium, and the upper side column, the magnetic core center column and the lower side column are drawn from the top The primary coil and the secondary coil are arranged on the central column of the magnetic core; a plurality of first media are uniformly distributed on the central column of the magnetic core along the longitudinal direction; and a plurality of second media are respectively arranged on the central column of the magnetic core. Between adjacent two turns of coils. The present disclosure can effectively reduce the magnetic leakage in the horizontal and vertical directions of the transformer, and realize the effect of low leakage inductance.

In order to make the objectives, technical solutions, and advantages of the present disclosure clearer, the following further describes the present disclosure in detail in conjunction with specific embodiments and with reference to the accompanying drawings.

Certain embodiments of the present disclosure will be described more fully in the following with reference to the accompanying drawings, and some but not all of the embodiments will be shown. In fact, various embodiments of the present disclosure can be implemented in many different forms, and should not be construed as being limited to the embodiments described in this number; relatively, the provision of these embodiments enables the present disclosure to meet applicable legal requirements.

FIG. 1 is a schematic structural diagram of an LTCC transformer adopting a transformer winding structure in the prior art. Fig. 2 is a schematic structural diagram of an LTCC transformer adopting a transformer winding structure in the prior art. As shown in Figure 1, when the transformer winding structure is used, the leakage flux distribution is shown by the arrow in Figure 2, which is divided into horizontal leakage flux and vertical leakage flux.

Among them, the horizontal leakage flux, as shown in Figure 2, is due to the LTCC transformer sintering the winding and the magnetic core together, resulting in a magnetic medium filled between two adjacent layers of conductors. Therefore, the reluctance of the magnetic medium between the two layers of conductors can be compared with the reluctance of the upper and lower legs of the transformer, resulting in leakage flux in the horizontal direction.

Among them, the vertical leakage flux is similar to the horizontal leakage flux. As shown in Figure 2, the LTCC transformer sinters the winding and the magnetic core together, which causes the magnetic medium to be filled between two adjacent turns of the winding. Therefore, the reluctance of the magnetic medium between two adjacent turns can be compared with the reluctance of the transformer core column and the side column of the magnetic core, which causes the leakage flux in the vertical direction. Different from the horizontal magnetic flux leakage, as the air gap of the magnetic core column increases, the magnetic resistance of the magnetic core column will further increase, resulting in a further increase of the vertical magnetic leakage flux.

Generally, the measures taken to reduce leakage inductance in practical applications are: the use of a staggered winding structure can reduce the leakage flux in the vertical direction, but it cannot solve the leakage flux in the horizontal direction. In particular, when an air gap is opened in the central column of the magnetic core, even if the interleaved winding structure is adopted, there is still a large leakage inductance. In the flyback converter, due to the existence of large leakage inductance, the main switch tube voltage stress is large, and the efficiency of the converter is reduced at the same time.

Fig. 3 is a schematic structural diagram of an LTCC transformer adopting a planar transformer winding structure in the prior art. As shown in Figure 3, the use of a planar transformer winding structure can effectively reduce the vertical leakage inductance. When the interleaved winding structure is adopted, the coupling coefficient between the primary and secondary of the transformer can be increased to more than 90%. However, as shown in Figure 3, it can be seen that, compared with the transformer winding structure, in the planar transformer winding structure, the overlapping area of the transformer primary and secondary is significantly increased, resulting in a larger parasitic capacitance. In the flyback converter, the parasitic capacitance limits the output voltage of the converter, and at the same time increases the winding loss of the transformer and reduces the efficiency.

In the first exemplary embodiment of the present disclosure, an LTCC high voltage transformer is provided. Fig. 4 is a schematic diagram of the structure of an LTCC high-voltage transformer according to an embodiment of the disclosure. As shown in Figure 4, the LTCC high voltage transformer of the present disclosure includes: upper side column 1, magnetic core center column 3, lower side column 2, primary coil 4, secondary coil 5, first medium 6 and second medium 7, upper side column 1, The core column 3 and the lower side column 2 are arranged in sequence from top to bottom, the primary coil 4 and the secondary coil 5 are fired in the core column 3; a plurality of first media 6 are uniformly distributed in the core along the longitudinal direction On the column 3, a plurality of second media 7 are respectively arranged between two adjacent turns of the coil. It should be noted here that two adjacent turns of the coil can make four turns of the primary wire, two turns of the secondary coil 5 or one turn of the primary coil 4 and one turn of the secondary coil 5. In a specific embodiment, when the second medium 7 is arranged between two adjacent turns of the secondary coil 5, the second medium 7 can be arranged to fill the adjacent two turns of the secondary coil 5 completely. A plurality of connecting holes 8 are provided on the first medium 6. The materials of the upper side pillar 1 and the lower side pillar 2 are both high-permeability materials; and the material of the central pillar 3 of the magnetic core is a low-permeability material. It should be noted here that the permeability of high-permeability materials is not less than 400; the permeability of low-permeability materials is not more than 100.

The components of the LTCC high-voltage transformer of the present disclosure are described in detail below.

The high permeability material selected for the upper side pillar 1 is ESL 40012, but it is not limited to this, and other materials known to those skilled in the art that can achieve similar effects are applicable. According to actual design requirements, the upper side pillar 1 can be designed in different shapes, and the thickness is designed according to the requirements for leakage inductance and size. The relative permeability of the high-permeability material selected for the upper column 1 is greater than the relative permeability of the low-permeability material selected for the center column 3 of the magnetic core. By applying a high magnetic permeability material on the upper side pillar 1, the leakage flux in the horizontal direction of the LTCC high voltage transformer provided by the present disclosure is suppressed.

The high permeability material selected for the lower side pillar 2 is ESL 40011, but it is not limited to this, and other materials known to those skilled in the art that can achieve similar effects are applicable. It is the same as the high permeability material selected for the upper side column 1. According to actual design requirements, the lower side column 2 can be designed in different shapes, and the thickness is designed according to the requirements for leakage inductance and size. The relative permeability of the high-permeability material selected for the lower column 2 is greater than the relative permeability of the low-permeability material selected for the center column 3 of the magnetic core. By applying high-permeability materials on the lower side column 2, the leakage flux in the horizontal direction of the LTCC high-voltage transformer provided by the present disclosure is suppressed.

The low-permeability material selected for the column 3 of the magnetic core is ESL's 4926-R, but it is not limited to this, and other materials known to those skilled in the art that can achieve similar effects are applicable. According to actual design requirements, the central pillar 3 of the magnetic core can be designed in different shapes, and the thickness of two adjacent layers can be designed according to the withstand voltage strength and the requirements of the transformer for leakage inductance. The relative permeability of the low-permeability material selected for the central column 3 of the magnetic core is smaller than the relative permeability of the high-permeability material selected for the lower column 2 or the upper column 1. By applying a low-permeability material on the central pillar 3 of the magnetic core, the leakage flux in the horizontal direction of the LTCC high-voltage transformer provided by the present disclosure is suppressed.

The first medium 6 is a non-magnetic medium and serves as the air gap of the LTCC high-voltage transformer. According to the actual circuit needs, the thickness of the air gap is designed to meet the required excitation inductance.

In order to avoid delamination during the sintering process, the connecting holes 8 are provided with a plurality of connecting holes 8 on the first medium 6 of the central pillar 3 of the magnetic core for connecting the magnetic materials separated by the first medium 6.

The number of turns of the primary coil 4 is designed according to the needs of the actual circuit. The width and thickness of the primary coil 4 are further adjusted according to the requirements of the efficiency and the AC resistance and the limitation of the transformer volume.

The secondary coil 5 is similar to the primary coil 4. The number of turns is designed according to the needs of the actual circuit, and the width and thickness of the primary coil 4 are further adjusted according to the requirements of the AC resistance of the efficiency team and the limitation of the volume of the transformer.

The second medium 7 is a non-magnetic conductive medium, which is used to increase the magnetic resistance of the magnetic core column 3 in the vertical direction, thereby reducing the magnetic flux leakage of the magnetic core column 3 in the vertical direction.

So far, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. It should be noted that, in the drawings or the main body of the specification, the implementation manners that are not shown or described are all forms known to those of ordinary skill in the art, and are not described in detail. In addition, the above definitions of various elements and methods are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and those of ordinary skill in the art can simply modify or replace them.

Based on the above description, those skilled in the art should have a clear understanding of the LTCC high voltage transformer of the present disclosure.

In summary, the present disclosure provides an LTCC transformer, which can be used to replace high-voltage transformers in current high-reliability high-voltage applications (such as high-voltage ignition devices, atomic clock ion pump power supplies, vacuum electronic device power supplies, etc.), which greatly improves the reliability of the system It is a very promising technology to reduce the volume and reduce the cost. It has a very broad application prospect and is of great significance to the miniaturization of equipment.

It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "rear", "left", "right", etc., are only directions with reference to the drawings, not Used to limit the protection scope of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. When it may cause confusion in the understanding of the present disclosure, conventional structures or configurations will be omitted.

In addition, the shapes and sizes of the components in the figure do not reflect the actual sizes and proportions, but merely illustrate the content of the embodiments of the present disclosure. In addition, in the claims, any reference signs located between parentheses should not be constructed to limit the claims.

Similarly, it should be understood that in order to simplify the present disclosure and help understand one or more of the various disclosed aspects, in the above description of the exemplary embodiments of the present disclosure, the various features of the present disclosure are sometimes grouped together into a single embodiment, Figure, or its description. However, the disclosed method should not be interpreted as reflecting the intention that the claimed disclosure requires more features than those explicitly recorded in each claim. More precisely, as reflected in the following claims, the disclosure aspect lies in less than all the features of a single embodiment previously disclosed. Therefore, the claims following the specific embodiment are thus explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present disclosure.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present disclosure in further detail. It should be understood that the above descriptions are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

An LTCC high voltage transformer, wherein, from top to bottom, it includes an upper side column, a magnetic core center column and a lower side column in sequence; and also includes:

The primary coil and the secondary coil are fired in the central column of the magnetic core;

A plurality of first media are uniformly distributed on the central pillar of the magnetic core along the longitudinal direction;

A plurality of second media are respectively arranged between adjacent two-turn primary coils, two-turn secondary coils, or between the primary coil and the secondary coil.
The LTCC high-voltage transformer according to claim 1, further comprising:

A plurality of connecting holes are respectively arranged on the first medium.
The LTCC high-voltage transformer according to claim 1, wherein the material of the upper side pillar is a high permeability material, and the permeability of the high permeability material is not less than 400.
The LTCC high voltage transformer according to claim 1, wherein the material of the lower side column is a high permeability material, and the permeability of the high permeability material is not less than 400.
The LTCC high-voltage transformer according to claim 1, wherein the material of the pillar in the magnetic core is a low permeability material, and the permeability of the low permeability material is not greater than 100.
The LTCC high-voltage transformer according to claim 1, wherein the relative permeability of the upper side column and the lower side column is greater than the relative permeability of the central column of the magnetic core.
The LTCC high-voltage transformer according to claim 1, wherein the adjacent primary coils are filled with a plurality of the second dielectrics.