Coupling inductor and preparation method and application thereof

Abstract

The invention provides a coupling inductor and a preparation method and application thereof. The coupling inductor comprises a magnetic column and laminated double coils wound on the surface of the magnetic column. The preparation method comprises the following steps: (1) performing powder making and T-core forming on magnetic powder in sequence to obtain a middle column, and performing winding and cutting on a wire in sequence to obtain laminated double coils; and (2) putting the middle column in the step (1) into the laminated double coil, adding magnetic powder on the surface of the laminated double coil, and sequentially carrying out compression molding and electrode molding to obtain the coupling inductor. According to the invention, the laminated double coils are wound on the magnetic column, so that the purposes of reducing coil deformation and enhancing the reliability of the coupling inductor are achieved, and the coupling coefficient of the coupling inductor is improved.

Description

Technical Field

[0001] The present invention relates to a coupled inductor, and in particular to a coupled inductor and a preparation method and application thereof. Background Art

[0002] Inductance components are also called self-inductance components. If the magnetic flux generated by each coil in two or more coils is connected to another coil, these coils are said to be magnetically coupled, and the prepared inductance is called coupled inductance. Coupled inductance can be used in topology circuits such as SEPIC, Zeta or flyback, and can also be used as a common-mode transformer.

[0003] CN114156058A discloses a winding type integrally formed coupled inductor, comprising: a packaged magnet, a first coil and a second coil respectively arranged in the packaged magnet, and a first electrode, a second electrode, a third electrode, and a fourth electrode respectively arranged at the four corners of the magnet surface; the first coil is arranged on the outside of the second coil, and the two leads of the first coil are respectively connected to the first electrode and the second electrode, and the two leads of the second coil are respectively connected to the third electrode and the fourth electrode; the surfaces of the first coil and the second coil are provided with a polysulfone resin coating; the packaged magnet is a powdered amorphous material, and the iron powder with a silicon layer on the surface is hot-pressed with an adhesive and then annealed at 300-500°C. In this invention, the radially stacked double coil is different from the axially stacked double coil in that the radial area of ​​the hot pressing is increased and there is no radial fixation. During hot pressing, under the same pressure conditions, the coil is more likely to have adverse conditions such as outward expansion, resulting in serious deformation of the coil and the terminal relative to the magnet. Because it cannot be controlled, the reliability of the coupled inductor will be reduced.

[0004] CN216054236U discloses a molded coupled inductor. It includes an external magnet, two magnetic cores, two wires and four electrode pins. The two magnetic cores and the two wires are buried inside the external magnet. The two wires are respectively wound around at least a portion of the two magnetic cores. The two ends of the two wires are respectively connected to the four electrode pins. At least a portion of the electrode pins is located outside the external magnet. However, the coupling coefficient of the coupled inductor of the invention decreases as the axial center distance of the double coils increases, and the coupling coefficient is difficult to reach above 0.95.

[0005] Therefore, how to avoid coil deformation and prepare a coupled inductor with a high coupling coefficient is an important research direction in this field. Summary of the invention

[0006] The object of the present invention is to provide a coupled inductor with a high coupling coefficient and a preparation method and application thereof.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] One of the objectives of the present invention is to provide a coupled inductor, which comprises a magnetic column and a stacked double coil wound on the surface of the magnetic column.

[0009] In the present invention, a stacked double coil is wound on the magnetic column, thereby achieving the purpose of reducing coil deformation and enhancing the reliability of the coupled inductor, and improving the coupling coefficient of the coupled inductor.

[0010] As a preferred technical solution of the present invention, the winding method includes: winding two wires in layers on the surface of the magnetic column along the vertical axis direction of the magnetic column.

[0011] Preferably, two ends of the two wires are independently connected to four electrode lead wires.

[0012] Preferably, the conductive wire comprises an electrically conductive metal.

[0013] As a preferred technical solution of the present invention, a concave structure is arranged on the surface of the magnetic column.

[0014] Preferably, the recessed structure comprises any one of a groove, an opening, a pit or a thread, or a combination of at least two of them, wherein typical but non-limiting examples of the combination include: a combination of a groove and an opening, a combination of an opening and a pit, a combination of a pit and a thread, or a combination of a groove and a thread, etc.

[0015] Preferably, the volume fraction of the recessed volume of the recessed structure to the total volume of the magnetic column is 1 to 10%, wherein the volume fraction can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc., but is not limited to the listed values, and other unlisted values ​​within the value are also applicable.

[0016] Preferably, the conductive wire of the stacked double coil includes any one of a round wire, a flat wire or a multi-strand wire.

[0017] A second object of the present invention is to provide a method for preparing the coupled inductor as described in the first object, the preparation method comprising the following steps:

[0018] (1) The magnetic powder is powdered and T-core formed in sequence to obtain a center column, and the conductive wire is wound and cut in sequence to obtain a stacked double coil;

[0019] (2) placing the middle column of step (1) into the stacked double coil, adding magnetic powder on the surface of the stacked double coil, and then performing pressing and electrode forming in sequence to obtain the coupled inductor.

[0020] The present invention obtains a middle column by performing T-core molding on magnetic powder, prepares a laminated double coil on the middle column, and then performs integrated pressing molding, thereby achieving the purpose of reducing coil deformation and enhancing the reliability of the coupled inductor.

[0021] As a preferred technical solution of the present invention, the powder making method in step (1) comprises: granulating the magnetic powder and glue and then screening them.

[0022] Preferably, the mass ratio of the magnetic powder to the glue is 1-5%, wherein the mass ratio can be 1%, 2%, 3%, 4% or 5%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the mesh number of the sieving is 60-250 mesh, wherein the mesh number can be 60 mesh, 100 mesh, 150 mesh, 200 mesh or 250 mesh, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] As a preferred technical solution of the present invention, the pressure of the T-core molding in step (1) is 0.5 to 4 T / cm 2 Wherein the pressure may be 0.5T / cm 2 , 1T / cm 2 , 1.5T / cm 2 , 2T / cm 2 , 2.5T / cm 2 , 3T / cm 2 、3.5T / cm 2 or 4T / cm 2 The above values ​​are not limited to the above listed values, and other values ​​not listed in the above listed values ​​are also applicable.

[0025] Preferably, the density of the T-core after forming in step (1) is 2.5 to 7.5 g / cm 3 Wherein the density may be 2.5 g / cm 3 , 3g / cm 3 、3.5g / cm 3 , 4g / cm 3 4.5g / cm 3 , 5g / cm 3 , 5.5g / cm 3 , 6g / cm 3 、6.5g / cm 3 , 7g / cm 3 or 7.5g / cm 3 The above values ​​are not limited to the above listed values, and other values ​​not listed in the above listed values ​​are also applicable.

[0026] Preferably, after the T-core is formed in step (1), the center column is cured.

[0027] Preferably, the curing degree of the curing treatment is 5 to 30%, wherein the curing degree can be 5%, 10%, 15%, 20%, 25% or 30%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the curing method includes baking and curing.

[0029] As a preferred technical solution of the present invention, the winding method in step (1) includes: winding two conductive wires in layers along the central axis.

[0030] Preferably, the cutting in step (1) includes spot welding cutting.

[0031] The present invention adopts spot welding cutting, and the coil is cut and prepared into a spot welding finished product after spot welding with the lead frame, which has higher reliability than the non-spot welding coil.

[0032] As a preferred technical solution of the present invention, the pressing molding in step (2) includes cold pressing preforming and hot pressing molding performed sequentially.

[0033] Preferably, the temperature of the cold press preforming is 20-30°C, wherein the temperature can be 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C or 30°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the cold press preforming pressure is 1 to 5 T / cm 2 Wherein the pressure may be 1T / cm 2 , 2T / cm 2 , 3T / cm 2 , 4T / cm 2 or 5T / cm 2 The above values ​​are not limited to the above listed values, and other values ​​not listed in the above listed values ​​are also applicable.

[0035] Preferably, the cold press preforming time is 1 to 10 seconds, wherein the time can be 1s, 2s, 3s, 4s, 5s, 6s, 7s, 8s, 9s or 10s, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, a semi-finished product is obtained after the cold pressing preforming, and the degree of curing of the semi-finished product is >90%, wherein the degree of curing can be 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the temperature of the hot pressing molding is 150-300°C, wherein the temperature can be 150°C, 180°C, 200°C, 220°C, 240°C, 260°C, 280°C or 300°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] Preferably, the pressure of the hot pressing molding is 1 to 10 T / cm 2 Wherein the pressure may be 1T / cm 2 , 2T / cm 2 , 3T / cm 2 , 4T / cm 2 , 5T / cm 2 , 6T / cm 2 , 7T / cm 2 , 8T / cm 2 , 9T / cm 2 or 10T / cm 2 The above values ​​are not limited to the above listed values, and other values ​​not listed in the above listed values ​​are also applicable.

[0039] Preferably, the hot pressing molding time is 10 to 150 s, wherein the time may be 10 s, 20 s, 40 s, 60 s, 80 s, 100 s, 120 s, 140 s or 150 s, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0041] (1) The magnetic powder is successively powdered and pressurized to 0.5 to 4 T / cm 2 The T-core molding can obtain a density of 2.5 to 7.5 g / cm 3 The wires are wound and cut in sequence to obtain a stacked double coil;

[0042] (2) placing the middle column of step (1) into the stacked double coil, adding magnetic powder to the surface of the stacked double coil, and then sequentially performing pressing and electrode forming to obtain the coupled inductor, wherein the pressing and forming comprises a temperature of 20 to 30° C. and a pressure of 1 to 5 T / cm 2Cold preforming with a time of 1 to 10 seconds and a temperature of 150 to 300°C and a pressure of 1 to 10 T / cm 2 And hot pressing preforming for 10 to 150 seconds.

[0043] A third object of the present invention is to provide an application of a coupled inductor as described in the first object, wherein the coupled inductor is applied in the field of inductance.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The coupled inductor prepared by the present invention has a low coil deformation rate and high coupled inductor reliability, and the coupling coefficient of the coupled inductor can reach above 0.95. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a structural diagram of the coupled inductor in Examples 1-6 of the present invention.

[0047] Figure 2 It is an axial diagram of the coupled inductor in Examples 1-6 of the present invention.

[0048] Figure 3 This is the surface structure of the magnetic column in Examples 1-6 of the present invention.

[0049] Figure 4 It is a flow chart of the preparation of coupled inductors in Examples 1-3 of the present invention. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0051] The present invention provides a coupled inductor, which comprises a magnetic column and a stacked double coil wound on the surface of the magnetic column.

[0052] Furthermore, the winding method includes: winding two wires in layers on the surface of the magnetic column along the vertical axis direction of the magnetic column.

[0053] Furthermore, two ends of the two wires are independently connected to four electrode lead wires.

[0054] Furthermore, the conductive wire comprises conductive metal.

[0055] Furthermore, a concave structure is arranged on the surface of the magnetic column.

[0056] Furthermore, the recessed structure includes any one of a groove, an opening, a pit or a thread, or a combination of at least two of them.

[0057] Furthermore, the volume fraction of the recessed volume of the recessed structure to the total volume of the magnetic column is 1-10%.

[0058] Furthermore, the conductor of the stacked double coil includes any one of a round wire, a flat wire or a multi-strand wire.

[0059] Example 1

[0060] This embodiment provides a Figure 1 The coupled inductor shown in FIG. 1 has an axial diagram of the coupled inductor as shown in FIG. Figure 2 As shown, the coupled inductor includes a magnetic column and a stacked double coil wound on the surface of the magnetic column. The winding method includes: winding two wires on the surface of the magnetic column in layers along the vertical axis direction of the magnetic column, and the two ends of the two wires are independently connected to four electrode pins, and the wires include conductive metal.

[0061] A concave structure is provided on the surface of the magnetic column, such as Figure 3 As shown, the concave structure is a groove structure, the volume fraction of the concave volume of the concave structure to the total volume of the magnetic column is 5%, and the conductive wire of the stacked double coil is a round wire.

[0062] This embodiment also provides a method for preparing the coupled inductor. The flowchart of the method is as follows: Figure 4 As shown, the preparation method comprises:

[0063] (1) Powdering the magnetic powder, which includes: granulating the magnetic powder and glue and then screening, the mass ratio of the magnetic powder to the glue is 3%, the mesh number of the screening is 150 mesh, and the pressure after the powdering is 2.5 T / cm 2 T-core molding, the density is 5g / cm 3 The middle column of the T-core is cured by baking after forming, and the degree of curing is 17%. The wires are wound and spot welded and cut in sequence to obtain a stacked double coil. The winding method is: two wires are stacked and wound along the central axis.

[0064] (2) placing the middle column of step (1) into the stacked double coil, adding magnetic powder to the surface of the stacked double coil, and then sequentially performing pressing and electrode forming to obtain the coupled inductor, wherein the pressing includes a temperature of 25° C. and a pressure of 3 T / cm 2 The cold preforming process was performed for 5 seconds at a temperature of 220°C and a pressure of 5T / cm 2 and hot pressing preforming for 80s.

[0065] Example 2

[0066] This embodiment provides a Figure 1 The coupled inductor shown in FIG. 1 has an axial diagram of the coupled inductor as shown in FIG. Figure 2 As shown, the coupled inductor includes a magnetic column and a stacked double coil wound on the surface of the magnetic column. The winding method includes: winding two wires on the surface of the magnetic column in layers along the vertical axis direction of the magnetic column, and the two ends of the two wires are independently connected to four electrode pins, and the wires include conductive metal.

[0067] A concave structure is provided on the surface of the magnetic column, such as Figure 3 As shown, the concave structure is a groove structure, the volume fraction of the concave volume of the concave structure to the total volume of the magnetic column is 5%, and the conductive wire of the stacked double coil is a round wire.

[0068] This embodiment also provides a method for preparing the coupled inductor. The flowchart of the method is as follows: Figure 4 As shown, the preparation method comprises:

[0069] (1) Powdering the magnetic powder, which includes: granulating the magnetic powder and glue and then screening, the mass ratio of the magnetic powder to the glue is 1%, the mesh size of the screening is 60 mesh, and the pressure after the powdering is 0.5 T / cm 2 T-core molding, the density is 2.5g / cm 3 After the T-core is formed, the center column is cured by baking, and the degree of curing is 5%. The wires are wound and spot welded and cut in sequence to obtain a stacked double coil. The winding method is: two wires are stacked and wound along the center axis.

[0070] (2) placing the middle column of step (1) into the stacked double coil, adding magnetic powder to the surface of the stacked double coil, and then sequentially performing pressing and electrode forming to obtain the coupled inductor, wherein the pressing includes a temperature of 20° C. and a pressure of 1 T / cm 2 The cold preforming time is 1s and the temperature is 150℃ and the pressure is 1T / cm 2 and hot pressing for 10 s.

[0071] Example 3

[0072] This embodiment provides a Figure 1 The coupled inductor shown in FIG. 1 has an axial diagram of the coupled inductor as shown in FIG. Figure 2As shown, the coupled inductor includes a magnetic column and a stacked double coil wound on the surface of the magnetic column. The winding method includes: winding two wires on the surface of the magnetic column in layers along the vertical axis direction of the magnetic column, and the two ends of the two wires are independently connected to four electrode pins, and the wires include conductive metal.

[0073] A concave structure is provided on the surface of the magnetic column, such as Figure 3 As shown, the concave structure is a groove structure, the volume fraction of the concave volume of the concave structure to the total volume of the magnetic column is 5%, and the conductive wire of the stacked double coil is a round wire.

[0074] This embodiment also provides a method for preparing the coupled inductor. The flowchart of the method is as follows: Figure 4 As shown, the preparation method comprises:

[0075] (1) Powdering the magnetic powder, which includes: granulating the magnetic powder and glue and then screening, the mass ratio of the magnetic powder to the glue is 5%, the mesh number of the screening is 250mesh, and the pressure is 4T / cm after the powdering is completed. 2 T-core molding, the density is 7.5g / cm 3 After the T-core is formed, the center column is cured by baking, and the degree of curing is 30%. The wires are wound and spot welded and cut in sequence to obtain a stacked double coil. The winding method is: two wires are stacked and wound along the center axis.

[0076] (2) placing the middle column of step (1) into the stacked double coil, adding magnetic powder to the surface of the stacked double coil, and then sequentially performing pressing and electrode forming to obtain the coupled inductor, wherein the pressing includes a temperature of 30° C. and a pressure of 5 T / cm 2 The cold preforming process was performed for 10 seconds at a temperature of 300°C and a pressure of 10T / cm 2 and hot pressing for 150s.

[0077] Example 4

[0078] Except for step (1) that the conductor is cut without spot welding after winding, other conditions in this embodiment are the same as those in embodiment 1.

[0079] Example 5

[0080] In this embodiment, hot pressing is directly performed instead of cold pressing, and other conditions are the same as those in embodiment 1.

[0081] Example 6

[0082] In this embodiment, except that hot pressing is not performed and cold pressing is used to obtain a product with a curing degree of 100%, other conditions are the same as those in embodiment 1.

[0083] Comparative Example 1

[0084] In this comparative example, except that the powdering and T-core molding of the magnetic powder are not performed, the magnetic powder is directly added to the stacked double coil for pressing and electrode molding, wherein the preparation method, pressing and electrode molding method of the stacked double coil are the same as those in Example 1.

[0085] Taking Example 1 as an example, the change rate of Ae of the axially stacked coupled inductor after compression and the change rate of Ae of the radially stacked coil after compression are explored, and the test results are shown in Table 1.

[0086] Table 1

[0087]

[0088] It can be seen from the above table that the change rate of Ae of the coupled inductor after compression in the axial stacking method is less than the change rate of Ae after compression in the radial stacking method.

[0089] The coupled inductors prepared in Examples 1-6 and Comparative Example 1 were tested for coil changes, basic electrical property differences of the coupled inductors, cold pressing preforming and hot pressing preforming test results, and coupled inductance values. The test results are shown in Table 2.

[0090] The coil change test method is as follows: the formed product is ground from the electrode surface to the geometric center of the product after baking, and the coil change is observed (axially stacked coil).

[0091] The basic electrical property difference of the coupled inductor is measured by an ammeter and a superposition meter to obtain data information.

[0092] The test method for the cold preforming and hot pressing test results is as follows: the difference in the inductance value of the coupled inductor of the product test after cold preforming and hot pressing is within ±5%, and the cold preforming pressure and hot pressing pressure results of each group of embodiments and comparative examples are compared.

[0093] The test method of inductance value is: use model CH3302 or CH3250 superposition instrument to measure.

[0094] Table 2

[0095]

[0096] It can be seen from the above table that the one-piece coupled inductor prepared by the preparation method of the present invention has a change in the inductance value L0 that is proportional to the change in the internal area Ae of the coil. The change rate of Ae after compression in the axial stacking method is less than that of the radial stacking coil. The molding L0 increases with the increase of the molding pressure within a certain range. The density of the magnetic center column is high, and L0 will increase accordingly.

[0097] By comparing Example 4 with Example 1, it can be seen that the spot welding cutting is replaced by non-spot welding cutting. Without spot welding cutting, the coil is placed in the cold pressing mold, which is not easy to position and it is difficult to ensure the positional relationship (verticality, flatness, etc.) between the coil and the mold. The deformation of the coil during the pressing process is more diverse and complex than that of the coil fixed by the lead frame, resulting in unstable inductance distribution.

[0098] It can be seen from Examples 5 and 6 that the change values ​​of the inductance value L0 and the saturation change rate of the T-core process are related to the type of press molding, and the change values ​​of the inductance value L0 and the saturation change rate of hot press molding are higher than those of cold press molding;

[0099] By comparing Example 1 and Comparative Example 1, it can be seen that after the product passes through T-core, the powder density in the coil will be higher than that of the powder directly cold-pressed or hot-pressed, the magnetic permeability of the powder will be higher, and the inductance will be higher.

[0100] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A coupled inductor, characterized in that: The coupled inductor comprises a magnetic column and a stacked double coil wound on the surface of the magnetic column.

2. The coupled inductor according to claim 1, characterized in that: The winding method comprises: winding two wires in layers on the surface of the magnetic column along the vertical axis direction of the magnetic column; Preferably, both ends of the two wires are independently connected to four electrode lead wires; Preferably, the conductive wire comprises an electrically conductive metal.

3. The coupled inductor according to claim 1 or 2, characterized in that: A concave structure is arranged on the surface of the magnetic column; Preferably, the recessed structure comprises any one of a groove, an opening, a pit or a thread, or a combination of at least two thereof; Preferably, the volume fraction of the concave volume of the concave structure to the total volume of the magnetic column is 1 to 10%; Preferably, the conductive wire of the stacked double coil includes any one of a round wire, a flat wire or a multi-strand wire.

4. A method for preparing a coupled inductor according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: (1) The magnetic powder is powdered and T-core formed in sequence to obtain a center column, and the conductive wire is wound and cut in sequence to obtain a stacked double coil; (2) placing the middle column of step (1) into the stacked double coil, adding magnetic powder on the surface of the stacked double coil, and then performing pressing and electrode forming in sequence to obtain the coupled inductor.

5. The preparation method according to claim 4, characterized in that: The powder making method in step (1) comprises: granulating the magnetic powder and glue and then screening them; Preferably, the mass ratio of the magnetic powder to the glue is 1 to 5%; Preferably, the mesh number of the sieving is 60-250 mesh.

6. The preparation method according to claim 4 or 5, characterized in that: The pressure of the T-core molding in step (1) is 0.5 to 4 T / cm 2 ; Preferably, the density of the T-core after forming in step (1) is 2.5 to 7.5 g / cm 3 ; Preferably, after the T-core is formed in step (1), the central column is cured; Preferably, the curing degree of the curing treatment is 5 to 30%; Preferably, the curing method includes baking and curing.

7. The preparation method according to any one of claims 4 to 6, characterized in that: The winding method in step (1) comprises: winding two conductive wires in layers along the central axis; Preferably, the cutting in step (1) includes spot welding cutting.

8. The preparation method according to any one of claims 4 to 7, characterized in that: The pressing and molding in step (2) includes cold pressing preforming and hot pressing forming performed sequentially; Preferably, the temperature of the cold pressing preforming is 20-30°C; Preferably, the cold press preforming pressure is 1 to 5 T / cm 2 ; Preferably, the cold pressing preforming time is 1 to 10 seconds; Preferably, the semi-finished product is obtained after the cold pressing preforming, and the curing degree of the semi-finished product is greater than 90%; Preferably, the temperature of the hot pressing molding is 150-300°C; Preferably, the pressure of the hot pressing molding is 1 to 10 T / cm 2 ; Preferably, the hot pressing molding time is 10 to 150 seconds.

9. The preparation method according to any one of claims 4 to 8, characterized in that: The preparation method comprises the following steps: (1) The magnetic powder is successively powdered and pressurized to 0.5 to 4 T / cm 2 The T-core molding can obtain a density of 2.5 to 7.5 g / cm 3 The wires are wound and cut in sequence to obtain a stacked double coil; (2) placing the middle column of step (1) into the stacked double coil, adding magnetic powder to the surface of the stacked double coil, and then sequentially performing pressing and electrode forming to obtain the coupled inductor, wherein the pressing and forming comprises a temperature of 20 to 30° C. and a pressure of 1 to 5 T / cm 2 Cold preforming with a time of 1 to 10 seconds and a temperature of 150 to 300°C and a pressure of 1 to 10 T / cm 2 And hot pressing preforming for 10 to 150 seconds.

10. An application of the coupled inductor according to any one of claims 1 to 3, characterized in that: The coupled inductor is applied in the field of inductance.

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