Magnetic integrated PFC inductor and PFC circuit

Abstract

The utility model provides a magnetic integrated PFC inductor and a PFC circuit, and belongs to the technical field of PFC inductors. Each magnetic side column of the inductor and the wound spiral coil form an inductor. The magnetic side columns are connected through the magnetic conductive plate, and a plurality of inductors are integrated into one device, so that the overall size is reduced. The magnetic side columns, the magnetic middle columns and the magnetic conductive plates form a closed magnetic circuit, namely, the magnetic side columns, the magnetic conductive plates, the magnetic middle columns, the magnetic conductive plates and the magnetic side columns, so that a magnetic field generated by the spiral coils on the magnetic side columns is spread along the closed magnetic circuit. Wherein the magnetic middle column with high magnetic conductivity guides magnetic circuits of the two adjacent magnetic side columns to the magnetic middle column, and the magnetic fields of the adjacent magnetic side columns are opposite in magnetic flux direction in the magnetic middle column and can counteract each other, so that the magnetic fluxes of the two magnetic side columns are not coupled with each other, and the mutual inductance effect can be reduced. Therefore, mutual inductance reduction by increasing the inductor distance can be avoided, and the overall size occupied by the inductor is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of PFC inductors, and in particular to a magnetically integrated PFC inductor and a PFC circuit. Background Art

[0002] A PFC (Power Factor Correction) circuit improves the power factor of a circuit through its circuit structure. PFC circuits are commonly used in power supply products or power modules in electronic devices. A PFC inductor is an inductor used in a PFC circuit.

[0003] A PFC circuit may require multiple PFC inductors to jointly implement the inductor function. For example, multiple PFC inductors can be connected in series to overcome the problem of a single PFC inductor having too low an inductance value. Existing methods typically arrange multiple independent PFC inductors on a PCB. On the one hand, these independent components require installation distance, and the volume they occupy must be greater than the sum of their individual volumes. On the other hand, to reduce the mutual inductance between inductors, the spacing between them is typically increased, which also increases the overall volume occupied by the inductors. Existing methods using multiple independent inductors occupy a large volume and are costly. The present invention adopts an all-in-one integrated design, which can reduce volume, save materials, and lower costs. Utility Model Content

[0004] The utility model provides a magnetically integrated PFC inductor and a PFC circuit to solve the problem of large volume of existing multi-PFC inductor structures.

[0005] In a first aspect, the utility model provides a magnetically integrated PFC inductor, comprising: magnetic side poles, a magnetic center pole, an upper magnetic conductive plate, and a lower magnetic conductive plate; the magnetic side poles are multiple; a magnetic center pole is arranged between adjacent magnetic side poles; the magnetic side poles are arranged parallel to the magnetic center pole; the upper magnetic conductive plate connects the upper ends of each magnetic side pole and the magnetic center pole; the lower magnetic conductive plate connects the lower ends of each magnetic side pole and the magnetic center pole; wherein the magnetic permeability of the magnetic center pole is greater than the magnetic permeability of the magnetic side poles, the upper magnetic conductive plate, and the lower magnetic conductive plate; a spiral coil is wound around each of the magnetic side poles; wherein the magnetic fields generated by the spiral coils of adjacent magnetic side poles have opposite magnetic flux directions in the magnetic center poles between the adjacent magnetic side poles.

[0006] In one possible implementation, the spiral coils of two adjacent magnetic side poles have opposite spiral directions and the same current direction, so that the magnetic fields generated by the spiral coils of adjacent magnetic side poles and the magnetic flux directions of the magnetic center pole between the adjacent magnetic side poles are opposite.

[0007] In one possible implementation, the spiral coils of two adjacent magnetic side poles have the same spiral direction and opposite current directions, so that the magnetic fields generated by the spiral coils of adjacent magnetic side poles have opposite magnetic flux directions in the magnetic center pole between the adjacent magnetic side poles.

[0008] In a possible implementation, the magnetic fields generated by the spiral coils of adjacent magnetic side poles have the same magnitude of magnetic flux in the magnetic center pole between the adjacent magnetic side poles.

[0009] In a possible implementation, the number of the magnetic side poles is 2, and the number of the magnetic center pole is 1; or, the number of the magnetic side poles is 3, and the number of the magnetic center poles is 2.

[0010] In a possible implementation, the magnetic side columns, the upper magnetic conductive plate, and the lower magnetic conductive plate are made of iron powder core material; and the magnetic center column is made of ferrite material.

[0011] In a possible implementation, the length of the magnetic center column is equal to the distance between the upper magnetic conductive plate and the lower magnetic conductive plate.

[0012] In a possible implementation, the spiral coil is a flat wire vertically wound coil.

[0013] In a possible implementation, the effective cross-sectional area of ​​the magnetic center column is 0.2 to 0.5 times the effective cross-sectional area of ​​the magnetic side columns.

[0014] In a second aspect, the present invention provides a PFC circuit, comprising the magnetically integrated PFC inductor as described in any one of the possible implementations above.

[0015] The utility model provides a magnetically integrated PFC inductor and a PFC circuit. Each magnetic side pole and the wound spiral coil of the utility model constitute an inductor. The magnetic side poles are connected by a magnetic conductive plate, and multiple inductors are integrated into one device, which reduces the overall volume. The magnetic side poles, the magnetic center pole and the magnetic conductive plate constitute a closed magnetic circuit, that is, the magnetic side pole-magnetic conductive plate-magnetic center pole-magnetic conductive plate-magnetic side pole, so that the magnetic field generated by the spiral coil on the magnetic side pole propagates along the closed magnetic circuit. Among them, the magnetic center pole with high magnetic permeability guides the magnetic circuit of the two adjacent magnetic side poles to the magnetic center pole, and because the magnetic fields of the adjacent magnetic side poles are opposite in direction in the magnetic flux of the magnetic center pole and can cancel each other out, the magnetic fluxes of the two magnetic side poles are not coupled with each other, which can reduce the mutual inductance effect. In addition, it is possible to avoid reducing the mutual inductance by increasing the inductor spacing, thereby reducing the overall volume occupied by the inductor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0017] Figure 1 This is a schematic structural diagram of a magnetically integrated PFC inductor provided by an embodiment of the present utility model;

[0018] Figure 2 1 is a schematic diagram of a top view of the magnetically integrated PFC inductor provided in an embodiment of the present utility model;

[0019] Figure 3 This is a schematic diagram of the structure after the spiral coil is removed provided by an embodiment of the present utility model;

[0020] Figure 4 1 is a schematic diagram of a three-in-one inductor structure provided by an embodiment of the present invention;

[0021] Figure 5 Schematic diagram of magnetic circuit paths and loss distribution provided by an embodiment of the present invention;

[0022] Figure 6 This is another schematic diagram of path and loss distribution provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0023] To help those skilled in the art better understand this solution, the following will clearly describe the technical solutions in the embodiments of this solution in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of this solution, not all of it. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of this solution.

[0024] Throughout the specification, claims, and accompanying figures of this solution, the term "including" and any variations thereof mean "including, but not limited to," and are intended to cover non-exclusive inclusions and are not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish between different objects, not to describe a specific order.

[0025] The following is a detailed description of the implementation of the present invention with reference to the accompanying drawings:

[0026] Figure 1 A schematic structural diagram of a magnetically integrated PFC inductor provided in an embodiment of the present utility model. Figure 2It is a schematic diagram of the top structure of the magnetic integrated PFC inductor provided by an embodiment of the present utility model. Figure 2 for Figure 1 A top-down view of the . Figure 1 、 Figure 2 , including: magnetic side poles 1, magnetic center poles 2, upper magnetic conductive plates 3 and lower magnetic conductive plates 4; there are multiple magnetic side poles 1; a magnetic center pole 2 is arranged between adjacent magnetic side poles 1; the magnetic side poles 1 are arranged parallel to the magnetic center poles 2; the upper magnetic conductive plate 3 connects the upper ends of each magnetic side pole 1 and the magnetic center pole 2; the lower magnetic conductive plate 4 connects the lower ends of each magnetic side pole 1 and the magnetic center pole 2; wherein, the magnetic permeability of the magnetic center pole 2 is greater than the magnetic permeability of the magnetic side poles 1, the upper magnetic conductive plate 3 and the lower magnetic conductive plate 4; a spiral coil 5 is wound on each magnetic side pole 1; wherein, the magnetic field generated by the spiral coils 5 of adjacent magnetic side poles 1, the magnetic flux direction of the magnetic center pole 2 between the adjacent magnetic side poles 1 is opposite.

[0027] It should be noted that Figure 1 A protective layer is provided on the outermost side of the spiral coil 5, so Figure 1 The position of the spiral coil 5 is not shown in the spiral winding shape. It is not limited here that a protective layer needs to be provided on the outermost side of the spiral coil 5.

[0028] Figure 3 This is a schematic diagram of the structure after the spiral coil is removed provided by an embodiment of the present utility model; Figure 3 for Figure 1 Schematic diagram of the frame structure after removing the spiral coil 5. Figure 3 In some embodiments, the magnetic side poles 1, magnetic center pole 2, upper magnetic plate 3, and lower magnetic plate 4 constitute the main frame of the magnetic integrated PFC inductor. Exemplarily, the magnetic side poles 1, magnetic center pole 2, upper magnetic plate 3, and lower magnetic plate 4 are magnetic circuit materials. Exemplarily, the magnetic side poles 1, magnetic center pole 2, upper magnetic plate 3, and lower magnetic plate 4 function as magnetic conductors. Specifically, the magnetic side poles 1, magnetic center pole 2, upper magnetic plate 3, and lower magnetic plate 4 can form a closed magnetic circuit. The structure of the lower main frame is first described below.

[0029] In some embodiments, there are multiple magnetic side poles 1; a magnetic center pole 2 is arranged between adjacent magnetic side poles 1; and the magnetic side poles 1 and the magnetic center pole 2 are arranged in parallel.

[0030] Exemplarily, the number of magnetic side poles 1 is N, the number of magnetic center poles 2 is N-1, and N ≥ 2. For example, the number of magnetic side poles 1 is 2, and the number of magnetic center poles 2 is 1; or, the number of magnetic side poles 1 is 3, and the number of magnetic center poles 2 is 2.

[0031] Figure 4 Schematic diagram of the three-in-one inductor structure provided by the embodiment of the present invention. For the convenience of observation, the spiral coil 5 is not shown in the figure. Figure 4, the number of magnetic side poles 1 is 3, and the number of magnetic center poles 2 is 2. For example, a three-in-one inductor can be used as an inductor for a three-phase PFC circuit.

[0032] The following embodiments are described by taking two magnetic side poles 1 and one magnetic center pole 2 as an example.

[0033] Exemplarily, a magnetic center column 2 is provided between adjacent magnetic side columns 1 , for example, a magnetic center column 2 is provided between two magnetic side columns 1 .

[0034] For example, the magnetic side poles 1 and the magnetic center pole 2 are arranged in parallel. For the sake of convenience, the direction in which one end of the magnetic side pole 1 points is considered up, and the direction in which the other end points is considered down. The up and down here do not limit the installation direction.

[0035] Exemplarily, the effective cross-sectional area of ​​the magnetic center column 2 is 0.2 to 0.5 times the effective cross-sectional area of ​​the magnetic side column 1 .

[0036] For example, the effective cross-sectional area AE of the ferrite core column 2 is optimally set to be 0.2 to 0.5 times the effective cross-sectional area AE of the iron powder core side column 1, and may vary slightly depending on the shape.

[0037] It should be noted that the spacing between the magnetic side pillars 1 and the magnetic center pillar 2 is not limited here. It can usually be determined based on the size of the coil to be wound later, at least to ensure that there is enough space to set the spiral coil 5.

[0038] The following embodiment illustrates that the upper and lower magnetic conductive plates 4 connect the magnetic side poles 1 and the magnetic center pole 2 .

[0039] In some embodiments, the upper magnetic conductive plate 3 connects the upper ends of the magnetic side poles 1 and the magnetic center pole 2 ; the lower magnetic conductive plate 4 connects the lower ends of the magnetic side poles 1 and the magnetic center pole 2 .

[0040] It should be noted that the connection method between the magnetic conductive plate and the magnetic column is not limited here. For example, it can be a snap connection.

[0041] In some embodiments, the length of the magnetic center pillar 2 is equal to the distance between the upper magnetic conductive plate 3 and the lower magnetic conductive plate 4. That is, the length of the magnetic center pillar 2 cannot be too long and cannot penetrate deep into the magnetic conductive plates. The magnetic center pillar 2 cannot be inserted into the middle of the iron powder core's magnetic path; it only needs to contact the iron powder core surface. If the magnetic center pillar 2 penetrates deep into the magnetic conductive plates, local saturation is likely to occur. In other words, the portion of the magnetic center pillar 2 that enters the iron powder core's magnetic conductive plates will easily saturate, which means that the core's magnetic flux reaches its maximum saturation state.

[0042] It should be noted that the magnetic plate, magnetic side pillars 1, and magnetic center pillar 2 are all made of magnetic conductive materials. The connection between the magnetic plate, magnetic side pillars 1, and magnetic center pillar 2 means that the magnetic circuit can propagate through the connection, thus forming a closed magnetic circuit.

[0043] Regarding the closed magnetic circuit direction, for example, it can be magnetic side pole 1 - upper magnetic plate 3 - magnetic center pole 2 - lower magnetic plate 4 - magnetic side pole 1. Alternatively, it can be magnetic side pole 1 - lower magnetic plate 4 - magnetic center pole 2 - upper magnetic plate 3 - magnetic side pole 1. The specific magnetic circuit direction is determined by various factors, which will be explained in subsequent embodiments. First, the generation of the lower magnetic field will be explained. The generation of the inductive magnetic field is related to the spiral coil 5.

[0044] In some embodiments, a spiral coil 5 is wound around each magnetic side pole 1 .

[0045] For example, the spiral coil 5 is a flat wire vertically wound coil. Flat wire vertical winding is a technique in which a flat wire is wound perpendicularly to the spiral axis. Flat wire vertical winding can reduce the distributed capacitance between coils, reduce high-frequency loops, and improve EMC characteristics.

[0046] The above describes the magnetic side poles 1, magnetic center pole 2, upper magnetic conductive plate 3, lower magnetic conductive plate 4 and spiral coil 5. The following describes the lower magnetic permeability and magnetic flux direction.

[0047] In some embodiments, the magnetic permeability of the magnetic center column 2 is greater than the magnetic permeabilities of the magnetic side columns 1 , the upper magnetic conductive plate 3 , and the lower magnetic conductive plate 4 .

[0048] Exemplarily, the magnetic side columns 1, upper magnetic conductive plate 3, and lower magnetic conductive plate 4 are made of iron powder core material; the magnetic center column 2 is made of ferrite material. It should be noted that the magnetic permeability of ferrite material is generally much greater than that of iron powder core material. In this embodiment of the present invention, by configuring the magnetic center column 2 to be made of a high-permeability material and short-circuiting the upper and lower magnetic conductive plates, the magnetic path passing through the magnetic conductive plates is preferentially transmitted through the magnetic center column 2. The direction of the magnetic field in the lower magnetic center column 2 is described below.

[0049] Furthermore, in some embodiments, the magnetic fields generated by the spiral coils 5 of adjacent magnetic side poles 1 are such that the magnetic flux directions of the magnetic center poles 2 between the adjacent magnetic side poles 1 are opposite.

[0050] In the embodiment of the present invention, the magnetic center column 2 with high magnetic permeability guides the magnetic paths of the two adjacent magnetic side columns to the magnetic center column 2. Moreover, since the magnetic fields of the adjacent magnetic side columns have opposite directions in the magnetic flux of the magnetic center column 2 and can cancel each other out, the magnetic fluxes of the two magnetic side columns are not coupled with each other, thereby reducing the mutual induction effect.

[0051] The following embodiments illustrate how to achieve the reversal of magnetic flux direction.

[0052] In one possible implementation, the spiral directions of the spiral coils 5 of two adjacent magnetic side poles 1 are opposite and the current directions are the same, so that the magnetic fields generated by the spiral coils 5 of the adjacent magnetic side poles 1 and the magnetic flux directions of the magnetic center pole 2 between the adjacent magnetic side poles 1 are opposite.

[0053] Exemplarily, the helical direction of the helical coil 5 includes left-handed or right-handed.

[0054] Exemplarily, the current direction includes from top to bottom or from bottom to top. Please note that the "up" and "down" here refer to the up and down directions defined above. For example, "from top to bottom" means that the current enters the upper coil port of magnetic side column 1 and exits the lower coil port. For another example, "from bottom to top" means that the current enters the lower coil port of magnetic side column 1 and exits the upper coil port.

[0055] It should be noted that when the spiral coils 5 of two adjacent magnetic side poles 1 have opposite spiral directions and the current directions are the same, the magnetic circuit directions of the two coils are opposite in the magnetic center pole 2. The following embodiment provides another case where the magnetic circuit directions are opposite.

[0056] In one possible implementation, the spiral coils 5 of two adjacent magnetic side poles 1 have the same spiral direction and opposite current directions, so that the magnetic fields generated by the spiral coils 5 of adjacent magnetic side poles 1 have opposite magnetic flux directions of the magnetic center pole 2 between the adjacent magnetic side poles 1.

[0057] The above two embodiments can be selected based on the specific application scenario, whether the wiring is convenient, etc. For example, if used in series, the solution with the same spiral direction and opposite current direction is preferred.

[0058] In one possible implementation, the magnetic fields generated by the spiral coils 5 of adjacent magnetic side poles 1 have the same magnitude of magnetic flux in the magnetic center pole 2 between the adjacent magnetic side poles 1. When the magnetic paths are in opposite directions and the magnetic flux magnitudes are the same, the magnetic fields of the two adjacent coils in the magnetic center pole 2 can completely cancel each other out.

[0059] Each magnetic side pole 1 and the wound spiral coil 5 of the embodiment of the utility model constitute an inductor. The magnetic side poles 1 are connected by a magnetic conductive plate, and multiple inductors are integrated into one device, which reduces the overall volume. The magnetic side poles 1, the magnetic center pole 2 and the magnetic conductive plate constitute a closed magnetic circuit, that is, the magnetic side pole 1-magnetic conductive plate-magnetic center pole 2-magnetic conductive plate-magnetic side pole 1, so that the magnetic field generated by the spiral coil 5 on the magnetic side pole 1 propagates along the closed magnetic circuit. Among them, the magnetic center pole 2 with high magnetic permeability guides the magnetic circuit of the two adjacent magnetic side poles 1 to the magnetic center pole 2, and because the magnetic fields of the adjacent magnetic side poles 1 are opposite in direction in the magnetic flux of the magnetic center pole 2 and can cancel each other out, the magnetic fluxes of the two magnetic side poles 1 are not coupled with each other, which can reduce the mutual inductance effect. In addition, it is possible to avoid reducing the mutual inductance by increasing the inductor spacing, thereby reducing the overall volume occupied by the inductor.

[0060] The magnetically integrated PFC inductor of this embodiment offers low losses, improved efficiency, a compact size, and reduced copper and iron core costs. The two spiral coils 5 have opposite magnetic flux directions on the magnetic center leg 2, canceling each other out and thus reducing losses. For example, because the magnetic paths on the ferrite center leg 2 cancel each other out, the ferrite losses in the center leg are very low, ideally reaching zero.

[0061] When a PFC circuit is operating, each inductor must be independent, which necessitates decoupling. Decoupling involves removing the mutual coupling between multiple inductors. The high-permeability center column 2 acts as a common magnetic circuit to remove magnetic circuit coupling. A spiral coil 5 is wound around the low-permeability side columns 1, which serve as the cores of each inductor. For example, the center column 2 is made of ferrite, a high-permeability material, while the two side columns 1 are iron powder cores, low-permeability materials. Since the magnetic flux from the side columns preferentially follows the high-permeability path, the magnetic flux from both side columns will preferentially flow through the center column. If these two fluxes are directed in opposite directions, they will cancel each other out on the center column, theoretically achieving zero center column loss.

[0062] The high-permeability ferrite center leg shorts the two inductors to each other. The center leg shorts the flux from each side leg to the center leg, canceling it out in the center leg. The flux from the two side legs does not couple to each other. Furthermore, the flux in the center leg's ferrite is in opposite directions, canceling each other out.

[0063] In other words, the center ferrite acts like a conductor in a circuit, allowing the magnetic flux of each side leg to flow through the middle and cancel each other out, preventing the magnetic flux of the two side legs from flowing between them and coupling. In other words, the presence of the high permeability center leg allows the magnetic paths of the two side legs to be independent of each other, without coupling, and each leg acts as an independent inductor.

[0064] Figure 5 Schematic diagram of magnetic circuit paths and loss distribution provided by an embodiment of the present invention; Figure 6 This is another schematic diagram of path and loss distribution provided by an embodiment of the present invention. Figure 6 The middle spiral coil 5 partially blocks the magnetic side column 1. Different colors represent different magnetic flux sizes, with red being the largest and blue being the smallest. Figure 5 、 Figure 6 The magnetic simulation results show that the magnetic circuit is offset at the center column. The blue mark on the center column indicates extremely low losses. The magnetic simulation results verify that the magnetic circuit and losses are consistent with theory.

[0065] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A magnetically integrated PFC inductor, characterized in that: include: Magnetic side columns, magnetic middle columns, upper magnetic conductive plates and lower magnetic conductive plates; There are multiple magnetic side poles; a magnetic center pole is set between adjacent magnetic side poles; the magnetic side poles are set parallel to the magnetic center pole; The upper magnetic conductive plate is connected to the upper ends of the magnetic side pillars and the magnetic center pillar; the lower magnetic conductive plate is connected to the lower ends of the magnetic side pillars and the magnetic center pillar; wherein the magnetic permeability of the magnetic center pillar is greater than the magnetic permeability of the magnetic side pillars, the upper magnetic conductive plate and the lower magnetic conductive plate; A spiral coil is wound around each of the magnetic side poles; wherein, the magnetic fields generated by the spiral coils of adjacent magnetic side poles have opposite directions of magnetic flux of the magnetic center pole between the adjacent magnetic side poles.

2. The magnetic integrated PFC inductor according to claim 1, wherein: The spiral coils of two adjacent magnetic side poles have opposite spiral directions and the same current direction, so that the magnetic fields generated by the spiral coils of the adjacent magnetic side poles and the magnetic flux directions of the magnetic center pole between the adjacent magnetic side poles are opposite.

3. The magnetic integrated PFC inductor according to claim 1, wherein: The spiral coils of two adjacent magnetic side poles have the same spiral direction and opposite current directions, so that the magnetic fields generated by the spiral coils of the adjacent magnetic side poles and the magnetic flux directions of the magnetic center pole between the adjacent magnetic side poles are opposite.

4. The magnetic integrated PFC inductor according to claim 1, wherein: The magnetic field generated by the spiral coils of adjacent magnetic side poles makes the magnetic flux of the magnetic center pole between the adjacent magnetic side poles the same.

5. The magnetic integrated PFC inductor according to claim 1, wherein: The number of the magnetic side pillars is 2, and the number of the magnetic middle pillar is 1; Alternatively, the number of the magnetic side pillars is 3, and the number of the magnetic middle pillars is 2.

6. The magnetic integrated PFC inductor according to claim 1, wherein: The materials of the magnetic side columns, upper magnetic conductive plates and lower magnetic conductive plates are iron powder core materials; The material of the magnetic center column is ferrite.

7. The magnetic integrated PFC inductor according to claim 1, wherein: The length of the magnetic center column is equal to the distance between the upper magnetic conductive plate and the lower magnetic conductive plate.

8. The magnetic integrated PFC inductor according to claim 1, wherein: The spiral coil is a flat wire vertically wound coil.

9. The magnetic integrated PFC inductor according to claim 1, wherein: The effective cross-sectional area of ​​the magnetic center column is 0.2 to 0.5 times the effective cross-sectional area of ​​the magnetic side columns.

10. A PFC circuit, characterized in that: The invention comprises the magnetically integrated PFC inductor according to any one of claims 1 to 9.

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