High-frequency transformer

Abstract

The utility model discloses a high-frequency transformer which comprises a magnetic circuit part and a circuit part, the magnetic circuit part comprises a first magnetic core and a second magnetic core, the circuit part comprises a primary winding and a secondary winding, the first magnetic core and the second magnetic core are stacked, the primary winding is wound on the first magnetic core and the second magnetic core, and the secondary winding is wound on the first magnetic core. The primary winding is wound on the first magnetic core, and the secondary winding is wound on the first magnetic core and the second magnetic core, so that the primary winding is coupled with the first iron core and the second iron core, and the secondary winding is not coupled with the first magnetic core. When the magnetic core of the transformer is not coupled with the winding, generation of a leakage magnetic field is improved, the leakage inductance value is increased due to generation of the leakage magnetic field, equivalently, a resonant inductor is externally hung on the high-frequency transformer, so that the use of resonant inductor elements can be reduced, and the structure of the LLC circuit is simplified.

Description

Technical Field

[0001] The utility model relates to the field of transformers, in particular to a high-frequency transformer. Background Art

[0002] MOS tubes are set inside the charger to control the on and off of various components and circuits. Driving the MOS tube to work requires high power consumption, but using LLC circuits to drive the MOS tube can reduce power consumption. LLC circuits reduce the power consumption of driving the MOS tube by increasing the switching frequency. The method of increasing the switching frequency is usually to set a high-frequency transformer and multiple resonant inductor components. The high-frequency transformer is usually used in the LLC circuit inside the charger to transform and increase the switching frequency. In the LLC resonant circuit, when the switching frequency is higher than the resonant frequency, the LLC gain can be guaranteed to be 1, so that the high-frequency transformer in the LLC circuit can effectively convert energy, improve the energy conversion efficiency of the high-frequency transformer, and at the same time enable the MOS tube to be zero-voltage turned on (ZVS) and zero-current turned off (ZCS), thereby reducing the switching loss of the MOS tube.

[0003] In LLC circuits, multiple resonant inductance components are generally set to increase the switching frequency. When the MOS tube driving power consumption increases, the switching frequency of the LLC circuit needs to be increased, resulting in an increase in the number of resonant inductance components. In order to reduce the use of resonant inductance components and simplify the LLC circuit structure, it is usually necessary to find a way to increase the leakage inductance value of the transformer, use the leakage inductance value generated by the transformer to replace the resonant inductance component, reduce the number of resonant inductance components used, and achieve the purpose of simplifying the LLC circuit structure.

[0004] The existing common methods for increasing the leakage inductance of high-frequency transformers are: Figure 1 As shown, the transformer is wound by separating the primary and secondary windings, so that the primary and secondary windings of the high-frequency transformer are wound separately, and the coupling between the primary winding and the secondary winding is reduced, so as to increase the leakage inductance value of the high-frequency transformer. However, the increased leakage inductance value is limited and generally cannot meet the leakage inductance value required by the magnetic integrated high-frequency transformer; Figure 2 As shown, a double-slot frame is used to wind the high-frequency transformer, and a retaining wall is added between the primary and secondary sides of the high-frequency transformer to reduce the coupling degree of the primary and secondary sides. This method can effectively increase the leakage inductance value of the high-frequency transformer and can achieve the larger leakage inductance value required by the general magnetic integrated high-frequency transformer. However, this method is not good at controlling the leakage inductance value of the high-frequency transformer. Utility Model Content

[0005] In view of the shortcomings of the prior art, the utility model provides a high-frequency transformer.

[0006] The purpose of the utility model is achieved through the following solutions:

[0007] A high-frequency transformer comprises: a magnetic circuit portion and a circuit portion, wherein the magnetic circuit portion comprises a first magnetic core and a second magnetic core, and the circuit portion comprises a primary winding and a secondary winding, wherein the first magnetic core and the second magnetic core are stacked, the primary winding is wound around the first magnetic core and the second magnetic core, and the secondary winding is wound around the first magnetic core.

[0008] In one embodiment, the first magnetic core and the second magnetic core are in a ring shape.

[0009] In one embodiment, an insulating isolation layer is further provided at the stacking position of the first magnetic core and the second magnetic core, wherein the insulating isolation layer is used to isolate the first magnetic core and the second magnetic core from each other, and one end surface of the insulating isolation layer is in abutment contact with the first magnetic core, and the other end surface is in abutment contact with the second magnetic core.

[0010] In one embodiment, the insulating isolation layer is disposed around the first magnetic core and the second magnetic core.

[0011] In one embodiment, a base is further included, and the first magnetic core and the second magnetic core are both disposed on the base.

[0012] In one embodiment, an adhesive layer is further provided on the base, one side of the adhesive layer is connected to the first magnetic core and the second magnetic core, and a side of the adhesive layer away from the first magnetic core and the second magnetic core is connected to the base.

[0013] In one embodiment, the primary winding and the secondary winding are made of copper.

[0014] Compared with the prior art, the utility model has at least the following advantages:

[0015] The utility model relates to a high-frequency transformer, in which the primary winding is wound on the first magnetic core, and the secondary winding is wound on the first magnetic core and the second magnetic core, so that the primary winding is coupled with both the first core and the second core, and the secondary winding is not coupled with the first magnetic core. When the magnetic core of the transformer is not coupled with the winding, the generation of the leakage magnetic field is increased, and the generation of the leakage magnetic field increases the leakage inductance value, which is equivalent to an external resonant inductor on the high-frequency transformer, thereby reducing the use of resonant inductor components, thereby simplifying the structure of the LLC circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0017] Figure 1 The transformer is wound by using the primary and secondary separation winding method;

[0018] Figure 2 To use a double slot bobbin to wind the transformer;

[0019] Figure 3 It is a side view of the utility model;

[0020] Figure 4 This is a front view of the utility model;

[0021] Figure 5 This is a rear view of the utility model;

[0022] Figure 6 is the cross section of the second magnetic core in the utility model;

[0023] Figure 7 It is an exploded view of the magnetic circuit part of the utility model;

[0024] Figure 8 It is a front view of the second magnetic core of the utility model;

[0025] Among them, the figure markings are, 1. magnetic circuit part; 11. first magnetic core; 12. second magnetic core; 2. circuit part; 21. primary winding; 22. secondary winding; 3. insulating isolation layer; 4. base; 41. adhesive layer. DETAILED DESCRIPTION

[0026] The following will disclose multiple embodiments of the present invention with drawings. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. In other words, in some embodiments of the present invention, these practical details are not necessary. In addition, in order to simplify the drawings, some conventional structures and components will be depicted in a simple schematic manner in the drawings.

[0027] It should be noted that all directional indications such as up, down, left, right, front, back... in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture as shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly.

[0028] In addition, in the present utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present utility model. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0029] In order to further understand the content, features and effects of the utility model, the following embodiments are given as examples and described in detail with reference to the accompanying drawings:

[0030] like Figure 3 As shown, this embodiment provides a high-frequency transformer, including: a magnetic circuit part 1 and a circuit part 2. The magnetic circuit part 1 is used to form a closed magnetic circuit to generate electromagnetic induction with the electric energy input to the high-frequency transformer; the circuit part 2 is used to increase or decrease the voltage input to the high-frequency transformer, and then output it to the subsequent circuit. When the high-frequency transformer is set in the LLC circuit, it is installed and placed through the base 4.

[0031] Specifically, refer to Figure 3 , Figure 4 and Figure 5 , the magnetic circuit part 1 includes a first magnetic core 11 and a second magnetic core 12, the circuit part 2 includes a primary winding 21 and a secondary winding 22, the first magnetic core 11 and the second magnetic core 12 are stacked, the primary winding 21 is wound around the first magnetic core 11 and the second magnetic core 12, and the secondary winding 22 is wound around the first magnetic core 11. The first magnetic core 11 and the second magnetic core 12 are both arranged on the base 4, the primary winding 21 is wound around the first magnetic core 11 and the second magnetic core 12, and is coupled with the first magnetic core 11 and the second magnetic core 12; the secondary winding 22 is wound around the first magnetic core 11 and is coupled with the first magnetic core 11.

[0032] It should be noted that a portion of the second magnetic core 12 is only wound with the primary winding 21, and another portion of the second magnetic core 12 is not wound with the primary winding 21 and the secondary winding 22. Therefore, the portion of the second magnetic core 12 that is not wound with the primary winding 21 and the secondary winding 22 is not coupled with the primary winding 21 and the secondary winding 22, so that the magnetic flux cannot pass through, so that the portion of the magnetic flux that is wound and coupled with the primary winding 21 of the second magnetic core 12 is released into the air, resulting in magnetic leakage of the high-frequency transformer. The leakage of the magnetic flux of the high-frequency transformer will increase the leakage inductance value of the high-frequency transformer, and further increase the resonant inductance of the high-frequency transformer, which is equivalent to an external resonant inductor on the high-frequency transformer. Therefore, the use of resonant inductor components can be reduced in the LLC circuit, thereby simplifying the LLC circuit structure.

[0033] Reference Figure 4 and Figure 5 Preferably, the first magnetic core 11 and the second magnetic core 12 are in a ring shape. The magnetic field of the ring-shaped magnetic core is evenly distributed and has high magnetic properties, so that the high-frequency transformer can improve the conversion efficiency when transforming voltage.

[0034] Reference Figure 3 Preferably, when the first magnetic core 11 and the second magnetic core 12 are stacked, an insulating isolation layer 3 is also provided at the stacking position of the first magnetic core 11 and the second magnetic core 12. The insulating isolation layer 3 is arranged around the first magnetic core 11 and the second magnetic core 12, and the insulating isolation layer (3) is used to isolate the first magnetic core (11) and the second magnetic core (12) from each other. One end face of the insulating isolation layer is in abutment with the first magnetic core 11, and the other end face is in abutment with the second magnetic core 12. It should be noted that the insulating isolation layer 3 can prevent the phenomenon of interlayer short circuit and interturn short circuit. In this embodiment, the insulating isolation layer 3 isolates the first magnetic core 11 and the second magnetic core 12 to prevent interlayer short circuit.

[0035] Reference Figure 3 Preferably, an adhesive layer 41 is further provided on the base 4, one side of the adhesive layer 41 is connected to the first magnetic core 11 and the second magnetic core 12, and the side of the adhesive layer away from the first magnetic core 11 and the second magnetic core 12 is connected to the base 4. The adhesive layer 41 can fix the first magnetic core 11 and the second magnetic core 12 on the base 4.

[0036] Preferably, the primary winding 21 and the secondary winding 22 are made of copper. Copper, as the material of the primary winding 21 and the secondary winding 22, has a relatively low line resistance. Since the high-frequency transformer operates at a relatively high frequency, the high-frequency transformer in operation will generate relatively high heat when current passes through it. Since the line resistance of copper is relatively low, it will not generate high heat, thereby preventing the high-frequency transformer from overheating and thus avoiding damage to the high-frequency transformer.

[0037] In summary, in this embodiment, reference Figure 6and Figure 8 , let r be the radius from the center of the second magnetic core 12 to the outer ring, h be the thickness of the second magnetic core 12, S be the effective cross-sectional area of ​​the second magnetic core 12, and since the cross-section is a rectangle, S=h*r can be obtained from the rectangular area formula.

[0038] like Figure 7 As shown, the air gap length L of the second magnetic core 12 δ is the stacking distance between the first magnetic core 11 and the second magnetic core 12 .

[0039] refer to Figure 8 , L f2 is the outer ring circumference length of the second magnetic core 12. The second magnetic core 12 is an annular cylinder. The circumference formula of the cylinder can be used to obtain L f2 =2πrh.

[0040] At the same time, let N be the number of turns of the primary winding 21 of the high-frequency transformer, μ f2 is the magnetic permeability of the second core, μ δ is the magnetic permeability of the air gap.

[0041] Therefore, according to the definition of inductance L = Ψ / I, and the calculation formula of the inductance in the transformer L = N * Ф / I, the calculation formula of the leakage inductance in the transformer can be deduced as L = N 2 S / (L f2 / μ f2 +L δ / μ δ ). It can be known that the leakage inductance value is proportional to the square of the number of turns of the primary winding 21 and the cross-sectional area of ​​the second magnetic core 12. In specific work, since the material, cross-sectional area and size length of the first magnetic core 11 and the second magnetic core 12 of the high-frequency transformer are fixed values, when it is necessary to increase the leakage inductance value of the high-frequency transformer, the number of turns of the primary winding 21 can be increased to increase the leakage inductance value of the high-frequency transformer, so that the high-frequency transformer is equivalent to an external resonant inductor, thereby reducing the use of resonant inductor components, thereby simplifying the structure of the LLC circuit.

[0042] The above is only an embodiment of the present invention and is 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 in the scope of the claims of the present invention.

Claims

1. A high frequency transformer, characterized in that: include: A magnetic circuit portion (1) and a circuit portion (2), wherein the magnetic circuit portion (1) comprises a first magnetic core (11) and a second magnetic core (12), and the circuit portion (2) comprises a primary winding (21) and a secondary winding (22), wherein the first magnetic core (11) and the second magnetic core (12) are stacked, the primary winding (21) is wound around the first magnetic core (11) and the second magnetic core (12), and the secondary winding (22) is wound around the first magnetic core (11).

2. A high frequency transformer according to claim 1, characterized in that: The first magnetic core (11) and the second magnetic core (12) are in the shape of a ring.

3. A high frequency transformer according to claim 1, characterized in that: An insulating isolation layer (3) is also provided at the stacking position of the first magnetic core (11) and the second magnetic core (12), wherein the insulating isolation layer (3) is used to isolate the first magnetic core (11) and the second magnetic core (12) from each other, and one end surface of the insulating isolation layer (3) is in abutment contact with the first magnetic core (11), and the other end surface is in abutment contact with the second magnetic core (12).

4. A high frequency transformer according to claim 3, characterized in that: The insulating isolation layer (3) is arranged around the first magnetic core (11) and the second magnetic core (12).

5. A high frequency transformer according to claim 1, characterized in that: It also comprises a base (4), and the first magnetic core (11) and the second magnetic core (12) are both arranged on the base (4).

6. A high frequency transformer according to claim 5, characterized in that: The base (4) is also provided with an adhesive layer (41), one side of the adhesive layer (41) is connected to the first magnetic core (11) and the second magnetic core (12), and the side of the adhesive layer (41) away from the first magnetic core (11) and the second magnetic core (12) is connected to the base.

7. A high frequency transformer according to claim 1, characterized in that: The primary winding (21) and the secondary winding (22) are made of copper.

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