A three-inductor integrated core structure based on a dual-buck topology with bias inductors

Abstract

A three-inductor integrated magnetic core structure based on a dual-buck topology with bias inductors relates to the technical field of power electronic magnetic integration. The open sides of the EE core are relatively connected as one body, wherein the vertical arms of the core on both sides serve as winding posts to form inductors L1 and L2 respectively, the top core horizontal connecting arm, the middle core vertical arm and the bottom core horizontal connecting arm serve as a common magnetic circuit, and the additional core is a U-shaped core connected to the bottom of the EE core as one body, and its bottom end is a horizontal section serving as a winding post to form inductor L3. Air gaps are opened at the center of the three winding posts and air or low permeability material is added. On the basis of the EE core, an additional winding post and related magnetic circuit are added to form a structure with three winding posts and multiple common magnetic circuits. The addition of air gaps achieves better adaptability, which helps to reduce the overall volume, weight and loss of the inductor.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronic magnetic integration, and in particular to a three-inductor integrated magnetic core structure based on a dual-buck topology with bias inductors. Background Art

[0002] The traditional half-bridge circuit with output filter is a basic electronic building block used in high-frequency switching power converters and amplifiers. However, this topology has the problem of short circuit caused by the direct conduction of the bridge arm. Dead time is required to ensure that the two switches are not turned on at the same time, thereby causing a short circuit. The introduction of dead time will increase the total harmonic distortion.

[0003] The dual-buck topology with bias inductor does not have such disadvantages. Figure 1 As shown in the figure, the bidirectional half bridge is replaced by two parallel complementary unidirectional switching branches, and an additional inductor L is added between the two unidirectional branches. b , balancing the currents passing through the filter inductors L1 and L2, so that each filter inductor conducts only half of the output current, thereby achieving better filtering effect.

[0004] However, the additional inductor inevitably increases the size of the magnetic components. Traditional magnetic components are often the heaviest and largest components in a power supply system. Magnetic components are essential for transmitting and storing electrical energy. Their quality directly impacts converter performance, such as size, efficiency, and EMI, which is crucial for achieving voltage regulation in power systems. Therefore, to reduce the size and weight of magnetic components, increase power density, and achieve better electromagnetic compatibility, a new magnetic core structure is urgently needed for the dual-buck topology with bias inductor. Summary of the Invention

[0005] In order to address the shortcomings of the background technology, the present invention provides a three-inductor integrated magnetic core structure based on a dual-buck topology with bias inductance. On the basis of the EE magnetic core, an additional winding column and related magnetic circuit are added to form a structure with three winding columns and multiple common magnetic circuits. The addition of an air gap achieves better adaptability, which helps to reduce the overall volume, weight and loss of the inductor.

[0006] To achieve the above purpose, the present invention adopts the following technical solution: a three-inductor integrated core structure based on a dual-buck topology with bias inductors, comprising

[0007] The magnetic core body is composed of an EE magnetic core and an additional magnetic core. The open sides of the EE magnetic core are relatively arranged and connected as a whole to form a horizontal sun-shaped structure as the upper half of the magnetic core. The vertical arms of the magnetic core on both sides of the upper half of the magnetic core serve as the first winding post and the second winding post respectively, and form inductance L1 and inductance L2 respectively by winding coils. The top magnetic core horizontal connecting arm, the middle magnetic core vertical arm and the bottom magnetic core horizontal connecting arm in the upper half of the magnetic core serve as the first common magnetic circuit, the second common magnetic circuit and the third common magnetic circuit respectively. The additional magnetic core is a U-shaped magnetic core and its open side is connected to the two sides of the bottom of the upper half of the magnetic core as a whole as the lower half of the magnetic core. The bottom end of the additional magnetic core is a horizontal section as the third winding post, and forms the inductance L3 by winding coils. Air gaps are respectively opened at the center positions of the first winding post, the second winding post and the third winding post, and air or a material with a magnetic permeability lower than the magnetic permeability of vacuum is added to the air gap.

[0008] Furthermore, the magnetic core body also defines an air gap at the center of the second common magnetic circuit.

[0009] Furthermore, the magnetic core body further defines an air gap on the third common magnetic circuit at a center position between the first winding post and the second common magnetic circuit or at a center position between the second common magnetic circuit and the second winding post.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: on the basis of the EE magnetic core, the present invention adds an additional winding column and related magnetic circuit at its bottom, forming a structure of three winding columns and multiple common magnetic circuits. By adding different air gaps, three design schemes of inductor uncoupling, two inductors coupling or three inductors simultaneous coupling can be realized. It has better adaptability to special circuit requirements, can further reduce the overall volume, weight and loss of the inductor, thereby obtaining better electromagnetic compatibility effect, achieving higher power density, improving inductor performance, and facilitating the promotion and application of inductors. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a dual buck topology diagram with bias inductor;

[0012] Figure 2 1 is a plan view of a first embodiment of a three-inductor integrated magnetic core structure according to the present invention;

[0013] Figure 3 yes Figure 2 Schematic diagram of the equivalent magnetic circuit;

[0014] Figure 4 1 is a plan view of a second embodiment of the three-inductor integrated magnetic core structure of the present invention;

[0015] Figure 5 yes Figure 4 Schematic diagram of the equivalent magnetic circuit;

[0016] Figure 6 1 is a plan view of a third embodiment of the three-inductor integrated magnetic core structure of the present invention;

[0017] Figure 7 yes Figure 6 Schematic diagram of the equivalent magnetic circuit.

[0018] In the figure: 1, first winding post; 2, second winding post; 3, third winding post; 4, first common magnetic circuit; 5, second common magnetic circuit; 6, third common magnetic circuit. DETAILED DESCRIPTION

[0019] The technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0020] like Figures 2 to 7 As shown, a three-inductor integrated magnetic core structure based on a dual-buck topology with bias inductors includes a magnetic core body, which is composed of an EE magnetic core and an additional magnetic core. The opening sides of the EE magnetic core are arranged relatively and connected as a whole to form a horizontal Japanese-shaped structure as the upper half of the magnetic core, and the additional magnetic core is a U-shaped magnetic core and its opening side is connected to the two sides of the bottom of the upper half of the magnetic core as a whole as the lower half of the magnetic core.

[0021] The vertical arms on both sides of the upper half of the core serve as the first winding post 1 and the second winding post 2, respectively, and form inductances L1 and L2 by winding coils, respectively. The top transverse connecting arm, the middle vertical arm, and the bottom transverse connecting arm of the core serve as the first common magnetic circuit 4, the second common magnetic circuit 5, and the third common magnetic circuit 6, respectively. The bottom end of the additional core is a horizontal section serving as the third winding post 3, and forms an inductance L3 by winding coils.

[0022] By adding different air gaps, there are three design options: uncoupled inductors, two-inductor coupling, or three-inductor simultaneous coupling. The specific designs are as follows:

[0023] Option 1

[0024] The core structure plan diagram of this design scheme is combined with Figure 2As shown, air gaps are defined at the center of each of the first winding leg 1, the second winding leg 2, and the third winding leg 3. Air or a material with a lower magnetic permeability than a vacuum is added to these air gaps. The magnetic resistance of the air gaps is significantly greater than that of the other magnetic circuits, and the magnetic resistance of the first, second, and third common magnetic circuits 4, 5, and 6 can be approximately zero. The vast majority of the magnetic flux generated by inductor L1 flows only through the first winding leg 1, the second common magnetic circuit 5, and the left halves of the first and third common magnetic circuits 4 and 6. The vast majority of the magnetic flux generated by inductor L2 flows only through the second winding leg 2, the second common magnetic circuit 5, and the right halves of the first and third common magnetic circuits 4 and 6. The vast majority of the magnetic flux generated by inductor L3 flows only through the third winding leg 3 and the third common magnetic circuit 6. It can be seen that the first and second common magnetic circuits 4 and 5 are common magnetic circuits for inductors L1 and L2, while the third common magnetic circuit 6 is common magnetic circuits for inductors L1, L2, and L3.

[0025] Since the magnetic resistance of the magnetic circuit is ignored, the mutual inductance coefficient between the inductors is very small and can be ignored. At this time, the inductors can be regarded as independent of each other. Figure 3 As shown in the figure, R1, R2, and R3 represent the three air gap reluctances, N1, N2, and N3 represent the corresponding magnetomotive force, and Φ1, Φ2, Φ3, Φ4, Φ5, and Φ6 represent the magnetic flux of the corresponding branch, where Φ5 = Φ1 + Φ2. The dashed lines indicate the direction of the magnetic flux flow in each winding. If no air gap is created on the non-winding legs and only the air gap reluctance is calculated, the magnetic flux generated by each winding flows only through its own small loop, and no coupling occurs between the inductors. If the magnetic flux flowing through a particular magnetic path is large, the winding method can be adjusted to offset some of the flux and reduce the core volume.

[0026] Option 2

[0027] The core structure plan diagram of this design scheme is combined with Figure 4 As shown, air gaps are defined at the center of each of the first winding post 1, the second winding post 2, and the third winding post 3. An air gap is also defined at the center of the second common magnetic circuit 5. Air or a material with a lower magnetic permeability than that of a vacuum is added to the air gaps. This results in a significantly greater magnetic resistance than the other magnetic circuits, and the magnetic resistance of the first common magnetic circuit 4 and the third common magnetic circuit 6 can be approximately zero. The magnetic flux generated by inductor L1 flows not only through the second common magnetic circuit 5, but also partially through the second winding post 2. The same applies to inductor L2. However, the vast majority of the magnetic flux generated by inductor L3 still flows only through the third winding post 3 and the third common magnetic circuit 6. It can be seen that the first winding post 1, the second winding post 2, and the second common magnetic circuit 5 form the common magnetic circuit for inductors L1 and L2, while the third common magnetic circuit 6 forms the common magnetic circuit for inductors L1, L2, and L3. In this case, inductors L1 and L2 are coupled, but inductor L3 remains independent.

[0028] Equivalent magnetic circuit combination Figure 5 As shown in the figure, R0, R1, R2, and R3 represent the four air gap reluctances, N1, N2, and N3 represent the corresponding magnetomotive force, Φ1, Φ2, Φ3, Φ4, Φ5, and Φ6 represent the magnetic flux in the corresponding branch, and the dotted lines indicate the direction of the magnetic flux in each winding. The direction of the dotted lines shows that the magnetic flux generated by N1 and N2 no longer flows only through their respective loops, indicating that inductors L1 and L2 are coupled. By adjusting the air gap length to change the reluctance, the appropriate coupling coefficient can be obtained.

[0029] Option 3

[0030] The core structure plan diagram of this design scheme is combined with Figure 6 As shown, air gaps are defined at the center of the first winding post 1, the second winding post 2, the third winding post 3, and the second common magnetic circuit 5. An air gap is also defined on the third common magnetic circuit 6, either at the center between the first winding post 1 and the second common magnetic circuit 5 or at the center between the second common magnetic circuit 5 and the second winding post 2. Air or a material with a lower magnetic permeability than that of a vacuum is added to the air gaps. In this case, the magnetic resistance of the air gaps is much greater than that of the other magnetic circuits, and the magnetic resistance of the first common magnetic circuit 4 can be approximately zero. At this point, the magnetic flux generated by each inductor no longer short-circuits due to the low-resistance magnetic circuit, and inductors L1, L2, and L3 are mutually coupled.

[0031] Equivalent magnetic circuit combination Figure 7 As shown in the figure, R0, R1, R2, R3, and R4 represent the four air gap reluctances, N1, N2, and N3 represent the corresponding magnetomotive force, Φ1, Φ2, Φ3, Φ4, Φ5, and Φ6 represent the magnetic flux in the corresponding branch, and the dotted lines indicate the direction of the magnetic flux in each winding. As can be seen from the direction of the dotted lines, the magnetic flux generated by each winding is no longer limited to a specific loop, and inductors L1, L2, and L3 begin to couple with each other.

[0032] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other configurations without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations coming within the meaning and range of equivalents of the claims are intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0033] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A three-inductor integrated magnetic core structure based on a dual-buck topology with bias inductors, characterized by: The invention comprises a magnetic core body, wherein the magnetic core body is composed of an EE magnetic core and an additional magnetic core, the opening sides of the EE magnetic core are arranged opposite to each other and connected as a whole to form a horizontal sun-shaped structure as the upper half of the magnetic core, the vertical magnetic core arms on both sides of the upper half of the magnetic core serve as a first winding post (1) and a second winding post (2), and form an inductance L1 and an inductance L2 by winding coils respectively, and the top magnetic core horizontal connecting arm, the middle magnetic core vertical arm and the bottom magnetic core horizontal connecting arm in the upper half of the magnetic core serve as a first common magnetic core in sequence. The additional magnetic core is a U-shaped magnetic core and its open side is connected to both sides of the bottom of the upper half of the magnetic core as a whole as the lower half of the magnetic core. The bottom end of the additional magnetic core is a horizontal section as the third winding column (3), and an inductance L3 is formed by winding a coil. Air gaps are respectively opened at the center positions of the first winding column (1), the second winding column (2) and the third winding column (3), and air or a material with a magnetic permeability lower than the magnetic permeability of vacuum is added to the air gaps.

2. The three-inductor integrated magnetic core structure based on a dual-buck topology with bias inductors according to claim 1, characterized in that: The magnetic core body also has an air gap at the center of the second common magnetic circuit (5).

3. The three-inductor integrated magnetic core structure based on a dual-buck topology with bias inductors according to claim 2, characterized in that: The magnetic core body also has an air gap on the third common magnetic circuit (6) at a central position between the first winding post (1) and the second common magnetic circuit (5) or at a central position between the second common magnetic circuit (5) and the second winding post (2).

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