transformers with low leakage inductance

Abstract

The utility model discloses a transformer with small leakage inductance, and the primary winding comprises a first wire cake, a second wire cake, a third wire cake, a fourth wire cake and a fifth wire cake, the second wire cake, the third wire cake, the fourth wire cake and the fifth wire cake are all 2-layer wire cakes with 15 turns of three-layer insulation wire, the secondary winding comprises a first secondary coil, a second secondary coil and a third secondary coil, the first secondary coil and the third secondary coil are both flat coils, the first wire cake and the second secondary coil are both wire cakes with three-layer insulation wire, the first wire cake, the second wire cake, the first secondary coil, the third wire cake, the second secondary coil, the fourth wire cake, the third secondary coil and the fifth wire cake are sequentially stacked from top to bottom, the second wire cake is connected with the fourth wire cake, the third wire cake is connected with the fifth wire cake, the second wire cake is connected with the third wire cake, and the fourth wire cake is connected with the fifth wire cake, so that the leakage inductance is greatly reduced, and the performance of the transformer is improved.

Description

Technical Field

[0001] This utility model relates to the field of transformers with low leakage inductance, and in particular to a transformer with low leakage inductance. Background Technology

[0002] Currently, as power supply products are developing towards higher power density and higher efficiency, planar transformers have significant advantages in improving the characteristics of switching power supplies and are widely used in DC / DC power modules due to their many advantages (such as high frequency, low profile, and low core loss).

[0003] Currently, planar transformers mainly adopt a flat coil structure. The primary and secondary coils of this type of planar transformer are both pre-formed flat coils, which have the advantages of convenient assembly, high production efficiency, and low material and labor costs.

[0004] However, due to the poor coupling between the primary and secondary coils of this type of planar transformer, its leakage inductance is relatively large, which can generate high-frequency spike pulse waveforms on an oscilloscope. For example, when the switching power supply is off, the energy stored in the leakage inductance needs to be released, creating noticeable noise; when the operating frequency of the planar transformer increases, the rate of change of current relative to time also increases, causing the leakage inductance to generate excessively high spike pulses. These excessively high spike pulses generated by the leakage inductance can damage the power devices in the transformer and create significant electromagnetic interference.

[0005] Therefore, a new technical solution needs to be developed to address the above problems. Utility Model Content

[0006] In view of this, the present invention addresses the deficiencies of the existing technology, and its main objective is to provide a transformer with low leakage inductance, which greatly reduces leakage inductance and improves transformer performance.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A transformer with low leakage inductance includes a magnetic core and primary and secondary windings wound on the central column of the magnetic core;

[0009] The primary winding includes a first coil, a second coil, a third coil, a fourth coil, and a fifth coil. The second coil, the third coil, the fourth coil, and the fifth coil are all two-layer coils wound with 15 turns of three-layer insulated wire.

[0010] The secondary winding includes a first primary coil, a second primary coil, and a third primary coil. The first primary coil and the third primary coil are both flat coils. The first coil and the second primary coil are both coils wound with three layers of insulated wire.

[0011] The first coil, the second coil, the first stage coil, the third coil, the second stage coil, the fourth coil, the third stage coil, and the fifth coil are stacked sequentially from top to bottom;

[0012] One end of the second and fourth thread cakes is connected, one end of the third and fifth thread cakes is connected, the other end of the second thread cake is connected to the other end of the third thread cake, and the other end of the fourth thread cake is connected to the other end of the fifth thread cake.

[0013] As a preferred embodiment, both the first coil and the second-stage coil are coils wound with two turns of three-layer insulated wire.

[0014] As a preferred embodiment, the second, third, fourth, and fifth coils are all two-layer coils made by winding 120 three-layer insulated wires with a diameter of 0.06mm for 15 turns.

[0015] As a preferred embodiment, both the primary and tertiary coils are flat coils wound with flat wire of 1mm*2.5mm.

[0016] As a preferred embodiment, the primary coil is a flat coil wound with 7 turns of flat wire with a specification of 1mm*2.5mm.

[0017] As a preferred embodiment, the third-stage coil is a flat coil wound with two turns of flat wire with a specification of 1mm*2.5mm.

[0018] As a preferred embodiment, the second, third, fourth, and fifth line cakes have the same thickness.

[0019] As a preferred embodiment, the thickness of the first coil is less than the thickness of the second coil, the thickness of the second coil is less than the thickness of the second coil, the thickness of the second coil is less than the thickness of the third coil, and the thickness of the third coil is less than the thickness of the first coil.

[0020] As a preferred embodiment, the first coil, the second coil, the first primary coil, the third coil, the second primary coil, the fourth coil, the third primary coil, and the fifth coil are wound in the same direction;

[0021] As a preferred embodiment, it also includes a base plate, the lower end face of which is provided with 9 welding feet for welding and fixing, and the upper end face of the base plate is provided with a first primary welding end, a second primary welding end, a third primary welding end and a fourth primary welding end that are respectively connected to 4 of the 9 welding feet;

[0022] One end of the fifth wire plate is connected to the first primary welding end, one end of the fourth wire plate is connected to the second primary welding end, and the two ends of the first wire plate are respectively connected to the third primary welding end and the fourth primary welding end.

[0023] The upper right side of the base plate is provided with a first-stage welding end, a second-stage welding end, a third-stage welding end, a fourth-stage welding end, a fifth-stage welding end, and a sixth-stage welding end, which are respectively connected to the other 5 of the 9 welding feet;

[0024] The two ends of the third-stage coil are connected to the first-stage welding end and the second-stage welding end, respectively. The two ends of the second-stage coil are connected to the third-stage welding end and the fourth-stage welding end, respectively. The two ends of the first-stage coil are connected to the fifth-stage welding end and the sixth-stage welding end, respectively.

[0025] Compared with the prior art, this utility model has obvious advantages and beneficial effects. Specifically, as can be seen from the above technical solution, it mainly uses a first coil, a second coil, a first secondary coil, a third coil, a second secondary coil, a fourth coil, a third secondary coil, and a fifth coil stacked from top to bottom, which greatly reduces leakage inductance and improves the performance of the transformer. Moreover, the secondary winding adopts a combination of flat coils and coils, and the secondary winding uses multiple coils to further reduce leakage inductance.

[0026] Secondly, using secondary coils with the same winding direction, the same thickness of the second to fifth coils, and different numbers of turns also plays a role in reducing leakage inductance.

[0027] To more clearly illustrate the structural features and effects of this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0028] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model;

[0029] Figure 2 This is a schematic diagram of another aspect of an embodiment of the present utility model;

[0030] Figure 3 This is a front view of an embodiment of the present utility model;

[0031] Figure 4 This is a simplified schematic diagram of coil stacking according to an embodiment of the present invention.

[0032] Explanation of reference numerals in the attached diagram:

[0033] 11. First magnetic core 12. Second magnetic core

[0034] 13. Convex column

[0035] 21. First-line pancake 22. Second-line pancake

[0036] 23. Third-line cake 24. Fourth-line cake

[0037] 25. Fifth-line cake

[0038] 31. First-stage coil 32. Second-stage coil

[0039] 33. Third-stage coil

[0040] 40. Base plate 401, weld foot

[0041] 41. First primary welding end 42. Second primary welding end

[0042] 43. Third primary welding end; 44. First primary welding end

[0043] 45. Secondary welding end 46. Tertiary welding end

[0044] 47. Fourth secondary welding end 48. Fifth secondary welding end

[0045] 49. The sixth secondary welding end. Detailed Implementation

[0046] Please refer to Figures 1 to 4 As shown, it illustrates the specific structure of an embodiment of the present invention, a transformer with low leakage inductance, including a magnetic core, a base plate 40, and a primary winding and a secondary winding sleeved on the central column of the magnetic core.

[0047] The magnetic core includes a first magnetic core 11 and a second magnetic core 12 arranged symmetrically on the top and bottom. Both the first magnetic core 11 and the second magnetic core 12 are E-type magnetic cores. A protruding post 13 is provided near the center position of both the first magnetic core 11 and the second magnetic core 12, and the two protruding posts 13 form the central post of the magnetic core.

[0048] The primary winding includes a first coil 21, a second coil 22, a third coil 23, a fourth coil 24, and a fifth coil 25. The first coil 21 is a coil wound with three layers of insulated wire. The second coil 22, the third coil 23, the fourth coil 24, and the fifth coil 25 are all two-layer coils wound with 15 turns of three-layer insulated wire. In this embodiment, the second coil 22, the third coil 23, the fourth coil 24, and the fifth coil 25 are all two-layer coils wound with 120 strands of three-layer insulated wire with a diameter of 0.06 mm, each with 15 turns. The thickness of the second coil 22, the third coil 23, the fourth coil 24, and the fifth coil 25 is equal.

[0049] The secondary winding includes a primary coil 31, a secondary coil 32, and a tertiary coil 33, both of which are flat coils. In this embodiment, both the primary coil 31 and the tertiary coil 33 are flat coils wound with 1mm*2.5mm flat wire. Preferably, the primary coil 31 is a flat coil wound with 7 turns of 1mm*2.5mm flat wire, and the tertiary coil 33 is a flat coil wound with 2 turns of 1mm*2.5mm flat wire.

[0050] The second-stage coil 32 is a coil wound with three layers of insulated wire. In this embodiment, both the first coil 21 and the second-stage coil 32 are coils wound with two turns of three layers of insulated wire.

[0051] The first coil 21, the second coil 22, the first-stage coil 31, the third coil 23, the second-stage coil 32, the fourth coil 24, the third-stage coil 33, and the fifth coil 25 are stacked sequentially from top to bottom. In this embodiment, the winding directions of the first coil 21, the second coil 22, the first-stage coil 31, the third coil 23, the second-stage coil 32, the fourth coil 24, the third-stage coil 33, and the fifth coil 25 are the same. The thickness of the first coil 21 is less than the thickness of the second-stage coil 32, the thickness of the second-stage coil 32 is less than the thickness of the second coil 22, the thickness of the second coil 22 is less than the thickness of the third-stage coil 33, and the thickness of the third-stage coil 33 is less than the thickness of the first-stage coil 31.

[0052] One end of the second thread 22 and the fourth thread 24 are connected, one end of the third thread 23 and the fifth thread 25 are connected, the other end of the second thread 22 is connected to the other end of the third thread 23, and the other end of the fourth thread 24 is connected to the other end of the fifth thread 25.

[0053] The base plate 40 is located below the second magnetic core 12. The lower end face of the base plate 40 is provided with nine welding feet 401 for welding and fixing. The upper end face of the base plate 40 is provided with a first primary welding end 41, a second primary welding end 42, a third primary welding end 43 and a fourth primary welding end 44 respectively connecting four of the nine welding feet 401. The first primary welding end 41, the second primary welding end 42, the third primary welding end 43 and the fourth primary welding end 44 are arranged in sequence from front to back.

[0054] One end of the fifth wire plate 25 is connected to the first primary welding end 41, one end of the fourth wire plate 24 is connected to the second primary welding end 42, and the two ends of the first wire plate 21 are respectively connected to the third primary welding end 43 and the fourth primary welding end 44.

[0055] The upper right side of the base plate 40 is provided with a first-stage welding end 44, a second-stage welding end 45, a third-stage welding end 46, a fourth-stage welding end 47, a fifth-stage welding end 48, and a sixth-stage welding end 49, which are respectively connected to the other 5 of the 9 welding feet 401.

[0056] The two ends of the third-stage coil 33 are respectively connected to the first-stage welding end 44 and the second-stage welding end 45. The two ends of the second-stage coil 32 are respectively connected to the third-stage welding end 46 and the fourth-stage welding end 401. The two ends of the first-stage coil 31 are respectively connected to the fifth-stage welding end 48 and the sixth-stage welding end 49.

[0057] The key design feature of this invention is that it is mainly achieved by stacking the first coil, the second coil, the first secondary coil, the third coil, the second secondary coil, the fourth coil, the third secondary coil, and the fifth coil in sequence from top to bottom, which greatly reduces leakage inductance and improves the performance of the transformer. Furthermore, the secondary winding uses a combination of flat coils and coils, and the secondary winding uses multiple coils to further reduce leakage inductance.

[0058] Secondly, using secondary coils with the same winding direction, the same thickness of the second to fifth coils, and different numbers of turns also plays a role in reducing leakage inductance.

[0059] The above description is merely a preferred embodiment of the present utility model and does not constitute any limitation on the technical scope of the present utility model. Therefore, any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. A transformer with low leakage inductance, comprising a magnetic core and a primary winding and a secondary winding wound on a central column of the magnetic core; characterized in that: The primary winding includes a first coil, a second coil, a third coil, a fourth coil, and a fifth coil. The second coil, the third coil, the fourth coil, and the fifth coil are all two-layer coils wound with 15 turns of three-layer insulated wire. The secondary winding includes a first primary coil, a second primary coil, and a third primary coil. The first primary coil and the third primary coil are both flat coils. The first coil and the second primary coil are both coils wound with three layers of insulated wire. The first coil, the second coil, the first stage coil, the third coil, the second stage coil, the fourth coil, the third stage coil, and the fifth coil are stacked sequentially from top to bottom; One end of the second and fourth thread cakes is connected, one end of the third and fifth thread cakes is connected, the other end of the second thread cake is connected to the other end of the third thread cake, and the other end of the fourth thread cake is connected to the other end of the fifth thread cake.

2. The transformer with low leakage inductance according to claim 1, characterized in that: Both the first coil and the second-stage coil are coils wound with two turns of three-layer insulated wire.

3. The transformer with low leakage inductance according to claim 1, characterized in that: The second, third, fourth, and fifth coils are all two-layer coils made by winding 120 three-layer insulated wires with a diameter of 0.06mm for 15 turns.

4. The transformer with low leakage inductance according to claim 1, characterized in that: Both the primary and tertiary coils are flat coils wound with flat wire of 1mm*2.5mm.

5. The transformer with low leakage inductance according to claim 4, characterized in that: The primary coil is a flat coil wound with 7 turns of flat wire with a specification of 1mm*2.5mm.

6. The transformer with low leakage inductance according to claim 4, characterized in that: The third-stage coil is a flat coil wound with two turns of flat wire with a specification of 1mm*2.5mm.

7. The transformer with low leakage inductance according to claim 1, characterized in that: The second, third, fourth, and fifth line cakes are all of equal thickness.

8. The transformer with low leakage inductance according to claim 7, characterized in that: The thickness of the first coil is less than the thickness of the second coil, the thickness of the second coil is less than the thickness of the second coil, the thickness of the second coil is less than the thickness of the third coil, and the thickness of the third coil is less than the thickness of the first coil.

9. The transformer with low leakage inductance according to claim 1, characterized in that: The first coil, the second coil, the first stage coil, the third coil, the second stage coil, the fourth coil, the third stage coil, and the fifth coil are wound in the same direction.

10. The transformer with low leakage inductance according to claim 1, characterized in that: It also includes a base plate, the lower end face of which is provided with 9 welding feet for welding and fixing, and the upper end face of the base plate is provided with a first primary welding end, a second primary welding end, a third primary welding end and a fourth primary welding end that are respectively connected to 4 of the 9 welding feet; One end of the fifth wire plate is connected to the first primary welding end, one end of the fourth wire plate is connected to the second primary welding end, and the two ends of the first wire plate are respectively connected to the third primary welding end and the fourth primary welding end. The upper right side of the base plate is provided with a first-stage welding end, a second-stage welding end, a third-stage welding end, a fourth-stage welding end, a fifth-stage welding end, and a sixth-stage welding end, which are respectively connected to the other 5 of the 9 welding feet; The two ends of the third-stage coil are connected to the first-stage welding end and the second-stage welding end, respectively. The two ends of the second-stage coil are connected to the third-stage welding end and the fourth-stage welding end, respectively. The two ends of the first-stage coil are connected to the fifth-stage welding end and the sixth-stage welding end, respectively.

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