Planar transformer capable of reducing leakage inductance of transformer
By adding a primary coil between the secondary coils of the planar transformer, the coupling between the primary and secondary coils is enhanced, solving the problems of high leakage inductance and high loss, and achieving stable operation of high voltage output.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 深圳市联明电源股份有限公司
- Filing Date
- 2025-05-06
- Publication Date
- 2026-05-26
AI Technical Summary
Existing planar transformers suffer from high leakage inductance, high device losses, and low conversion efficiency at high voltage output, resulting in unstable operation.
Adding a primary coil between the secondary coils increases the coupling between the primary and secondary coils. By placing the primary coil between the upper and lower coils, a secondary sandwich is formed, which enhances magnetic flux transmission and reduces leakage flux.
This reduces transformer leakage inductance, improves conversion efficiency, and reduces device losses, enabling planar transformers to operate stably in high-voltage output applications.
Smart Images
Figure CN224287982U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of transformer technology, specifically to a planar transformer that reduces transformer leakage inductance. Background Technology
[0002] In the field of modern power electronics, planar transformers have been widely used in numerous application scenarios due to their significant advantages such as small size, high power density, and ease of integration. Especially in low-voltage, high-current applications, planar transformers have demonstrated excellent performance and adaptability.
[0003] Currently, common planar transformers consist of a magnetic core and multiple sets of primary and secondary coils mounted on magnetic pillars surrounding the core. Each primary coil set includes two primary coils arranged side-by-side, with a secondary coil positioned between adjacent primary coil sets. Each secondary coil is wound from a single conductor. However, this type of planar transformer is limited to low-voltage, high-current applications. When the output voltage exceeds 100VDC, existing planar transformer technology reveals numerous problems. In principle, higher voltage necessitates a greater number of secondary turns, leading to issues such as high leakage inductance, high component losses, and low conversion efficiency. This results in current automated planar transformers being unable to operate stably at higher output levels. Utility Model Content
[0004] In order to overcome the problems of high leakage inductance, high device loss and low conversion efficiency of existing planar transformers, this utility model provides a planar transformer that reduces transformer leakage inductance.
[0005] The technical solution of this utility model is as follows:
[0006] A planar transformer for reducing transformer leakage inductance includes a magnetic core and multiple sets of primary coils and multiple sets of secondary coils mounted on magnetic posts of the magnetic core.
[0007] Each set of primary coils includes a primary coil disc;
[0008] A primary coil is provided between two adjacent sets of the secondary coils;
[0009] Each set of secondary coils is wound from a single wire, forming an upper coil and a lower coil. In a set of secondary coils, a primary coil is provided between the upper coil and the lower coil.
[0010] A primary coil is provided between the uppermost upper coil and the lowermost lower coil and the magnetic core.
[0011] In a preferred embodiment of this utility model, in a set of secondary coils, the number of turns of the upper coil is one more turn or one less turn than the number of turns of the lower coil.
[0012] In a preferred embodiment of this utility model, in two adjacent sets of secondary coils, the number of turns of the upper coil of one set of secondary coils is the same as the number of turns of the upper coil of the other set of secondary coils, and the number of turns of the lower coil of one set of secondary coils is the same as the number of turns of the upper coil of the other set of secondary coils.
[0013] In a preferred embodiment of this utility model, the number of turns of the upper coil of all the secondary coils is the same, and the number of turns of the lower coil of all the secondary coils is the same.
[0014] As a preferred embodiment of this utility model, the primary coil is a three-layer insulated coil.
[0015] As a preferred embodiment of this utility model, the diameter of the conductor of the primary coil is 0.15mm.
[0016] As a preferred embodiment of this utility model, the primary coil is made of seven wires wound in parallel, and the primary coil has twenty-one turns.
[0017] In a preferred embodiment of this utility model, the primary coil is a flat coil.
[0018] As a preferred embodiment of this utility model, the wire of the primary coil has a thickness and diameter of 0.5 mm and a width of 6 mm; the primary coil has ten turns.
[0019] In a preferred embodiment of this utility model, there are nine sets of primary coils and four sets of secondary coils.
[0020] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0021] This utility model provides a planar transformer for reducing transformer leakage inductance. Under the same magnetic core, volume, and wire material, by adding a secondary sandwich layer (i.e., adding a primary coil between the upper and lower coils), the coupling degree between the primary and secondary coils can be increased, allowing more magnetic flux to be effectively transferred between the primary and secondary windings, reducing leakage flux, thereby achieving the purpose of reducing transformer leakage inductance to improve conversion efficiency and reduce device losses. It effectively solves the problem of low conversion efficiency of existing planar transformers when outputting high voltage, enabling automated planar transformers to work stably in the field of higher voltage output. Attached Figure Description
[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model, 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 of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 This is a front view of a planar transformer for reducing transformer leakage inductance according to an embodiment of the present invention;
[0024] Figure 2 This is a schematic diagram showing the distribution of the primary coil and the secondary coil in one embodiment of the present invention;
[0025] Figure 3 This is a schematic diagram of a structure in one embodiment of the present invention, in which a primary coil is provided between the upper and lower coils of the secondary coil, wherein the upper coil has 5.5 turns and the lower coil has 4.5 turns.
[0026] Figure 4 This is a schematic diagram of another structure of the present invention, in which a primary coil is provided between the upper and lower coils of the secondary coil, wherein the upper coil has 4.5 turns and the lower coil has 5.5 turns.
[0027] Figure 5 This is a front view of an existing planar transformer;
[0028] Figure 6 This is a schematic diagram showing the distribution of the primary and secondary coils in an existing planar transformer.
[0029] Figure 7 This is a schematic diagram of a structure in an existing planar transformer where a set of secondary coils is placed between two adjacent sets of primary coils.
[0030] In the diagram,
[0031] 1. Magnetic core; 2. Primary coil; 21. Primary coil; 3. Secondary coil; 31. Upper coil; 32. Lower coil. Detailed Implementation
[0032] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. It is also declared that the embodiments described below are only for explaining this utility model and are not intended to limit this utility model.
[0033] It should be noted that the terms "installation," "setting," "connection," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly defined. Indications of orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used in the application's product, or the orientation or positional relationship commonly understood by those skilled in the art, and are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0034] Please see Figure 1 , Figure 2 The present invention provides a planar transformer for reducing transformer leakage inductance, comprising a magnetic core 1 and multiple sets of primary coils 2 and multiple sets of secondary coils 3 sleeved on the magnetic core 1. Each set of primary coils 2 includes a primary coil 21; a primary coil 21 is disposed between two adjacent sets of secondary coils 3; each set of secondary coils 3 is wound by a single wire to form an upper coil 31 and a lower coil 32, and a primary coil 21 is disposed between the upper coil 31 and the lower coil 32 in a set of secondary coils 3; a primary coil 21 is disposed between the uppermost upper coil 31 and the lowermost lower coil 32 and the magnetic core 1.
[0035] The planar transformer of this embodiment, with the same magnetic core 1, volume, and wire material, can increase the coupling between the primary coil 2 and the secondary coil 3 by adding a secondary sandwich layer (i.e., adding a primary coil 21 between the upper coil 31 and the lower coil 32). This allows more magnetic flux to be effectively transferred between the primary and secondary windings, reducing leakage flux and thereby reducing transformer leakage inductance to improve conversion efficiency and reduce device losses. It effectively solves the problem of low conversion efficiency of existing planar transformers when outputting high voltage, enabling automated planar transformers to work stably in higher voltage output fields.
[0036] Please see Figure 3 , Figure 4 In one embodiment, in a set of secondary coils 3, the upper coil 31 has one more turn than the lower coil 32. By having a one-turn difference in the number of turns between the upper coil 31 and the lower coil 32 in a set of secondary coils 3, the magnetic coupling between the primary coil 2 and the secondary coil 3 can be made more uniform, reducing leakage flux caused by uneven magnetic field distribution, thereby further reducing leakage inductance and improving the overall performance of the transformer.
[0037] In one embodiment, in two adjacent sets of secondary coils 3, the number of turns of the upper coil 31 of one set of secondary coils 3 is the same as the number of turns of the upper coil 31 of the other set of secondary coils 3, and the number of turns of the lower coil 32 of one set of secondary coils 3 is the same as the number of turns of the upper coil 31 of the other set of secondary coils 3. This winding method of the secondary coils 3 allows the in-phase output terminals of the two sets of secondary coils 3 to be close together. In actual transformer manufacturing and circuit connection, close proximity of the in-phase output terminals simplifies the connection process of the secondary coils 3, reduces the length and complexity of the connecting wires, lowers the connection resistance, and thus reduces additional component losses caused by the connection.
[0038] Of course, in another embodiment, the number of turns of the upper coil 31 of all secondary coils 3 can also be set to be the same, and the number of turns of the lower coil 32 of all secondary coils 3 can also be set to be the same. This utility model does not limit this. The above-described method of winding the number of turns of the secondary coils 3 makes the winding pattern of the secondary coils 3 of the entire planar transformer simple and uniform, which facilitates parameter calculation and optimization by designers, reduces the process difficulty and complexity in the manufacturing process, improves production efficiency, and reduces quality problems that may be caused by inconsistent winding.
[0039] In one embodiment, the primary coil 21 is a triple-insulated coil. Compared to a regular coil, a triple-insulated coil provides more reliable insulation protection, reduces the risk of coil damage due to poor insulation, helps extend the transformer's service life, reduces maintenance and replacement costs, and improves the reliability and stability of the equipment.
[0040] In one specific embodiment, the diameter of the conductor of the primary coil 21 is 0.15 mm, the primary coil 21 is made of seven conductors wound in parallel, and the number of turns of the primary coil 21 is twenty-one.
[0041] In one embodiment, the primary coil 2 is a flat coil. In modern power electronic devices, space is limited, and flat coils can better adapt to small spaces, improving the power density and integration of the device.
[0042] In one specific embodiment, the wire of the primary coil 2 has a thickness and diameter of 0.5 mm and a width of 6 mm; the primary coil 2 has ten turns.
[0043] The following is a detailed comparison of the differences between existing planar transformers and this utility model using a specific case:
[0044] Please see Figures 5 to 7A planar transformer includes a magnetic core 1 and five sets of primary coils 2 and four sets of secondary coils 3 mounted on magnetic pillars of the magnetic core 1. Each set of primary coils 2 includes two primary coils 21 arranged side by side, for a total of ten primary coils 21. A set of secondary coils 3 is located between two adjacent sets of primary coils 2. Each set of secondary coils 3 is wound with a single wire. The primary coils 21 are triple-insulated coils, and each primary coil 21 has twenty-one turns. Each set of secondary coils 3 has ten turns. This existing planar transformer is limited to applications in low-voltage, high-current fields. When the output voltage exceeds 100VDC, this existing planar transformer exhibits problems such as high leakage inductance, high component losses, and low conversion efficiency, causing current automated planar transformers to be unable to operate stably in high-output fields.
[0045] Please see Figures 1 to 4 This embodiment provides a planar transformer for reducing transformer leakage inductance, including a magnetic core 1 and nine sets of primary coils 2 and four sets of secondary coils 3 mounted on the magnetic core 1. Each set of primary coils 2 includes a primary coil 21, i.e., there are nine primary coils 21 in total. A primary coil 21 is disposed between two adjacent sets of secondary coils 3. Each set of secondary coils 3 is wound by a single wire, forming an upper coil 31 and a lower coil 32. In a set of secondary coils 3, a primary coil 21 is disposed between the upper coil 31 and the lower coil 32. A primary coil 21 is disposed between the uppermost upper coil 31 and the lowermost lower coil 32 and the magnetic core 1. Each primary coil 21 has twenty-one turns, and each set of secondary coils 3 has ten turns. In a set of secondary coils 3, the upper coil 31 has one more turn or one less turn than the lower coil 32. Compared with the existing planar transformers described above, the planar transformer of this embodiment, with the same magnetic core 1, volume, and wire material, can increase the coupling degree between the primary coil 2 and the secondary coil 3 by adding a secondary interlayer (i.e., adding a primary coil 21 between the upper coil 31 and the lower coil 32), so that more magnetic flux can be effectively transferred between the primary and secondary windings, reducing leakage flux, thereby achieving the purpose of reducing transformer leakage inductance to improve conversion efficiency and reduce device losses.
[0046] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.
[0047] The present utility model patent has been described above with reference to the accompanying drawings. Obviously, the implementation of the present utility model patent is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present utility model patent, or the direct application of the inventive concept and technical solution of the present utility model patent to other occasions without modification, are all within the protection scope of the present utility model.
Claims
1. A planar transformer for reducing transformer leakage inductance, comprising a magnetic core and multiple sets of primary coils and multiple sets of secondary coils sleeved on magnetic posts of the magnetic core, characterized in that, Each primary coil group comprises a primary coil disc; A primary coil is provided between two adjacent sets of the secondary coils; Each set of secondary coils is wound from a single wire, forming an upper coil and a lower coil. In a set of secondary coils, a primary coil is provided between the upper coil and the lower coil. A primary coil is provided between the uppermost upper coil and the lowermost lower coil and the magnetic core.
2. The planar transformer for reducing transformer leakage inductance according to claim 1, characterized in that, In a set of secondary coils, the upper coil has one more turn or one less turn than the lower coil.
3. The planar transformer for reducing transformer leakage inductance according to claim 1, characterized in that, In two adjacent sets of secondary coils, the number of turns of the upper coil in one set of secondary coils is the same as the number of turns of the upper coil in the other set of secondary coils, and the number of turns of the lower coil in one set of secondary coils is the same as the number of turns of the upper coil in the other set of secondary coils.
4. The planar transformer for reducing transformer leakage inductance according to claim 1, characterized in that, All the upper coils of the secondary coils have the same number of turns, and all the lower coils of the secondary coils have the same number of turns.
5. The planar transformer for reducing transformer leakage inductance according to claim 1, characterized in that, The primary coil is a three-layer insulated coil.
6. The planar transformer for reducing transformer leakage inductance according to claim 5, characterized in that, The diameter of the conductor in the primary coil is 0.15 mm.
7. The planar transformer for reducing transformer leakage inductance according to claim 5, characterized in that, The primary coil is made of seven wires wound in parallel, and the primary coil has twenty-one turns.
8. The planar transformer for reducing transformer leakage inductance according to claim 1, characterized in that, The primary coil is a flat coil.
9. The planar transformer for reducing transformer leakage inductance according to claim 8, characterized in that, The primary coil has a wire diameter of 0.5 mm and a width of 6 mm; the primary coil has ten turns.
10. The planar transformer for reducing transformer leakage inductance according to claim 1, characterized in that, The primary coil has nine sets, and the secondary coil has four sets.