Three-inductor integrated magnetic core structure based on biased inductor double-step-down topology

Abstract

The invention discloses a three-inductor integrated magnetic core structure based on a biased inductor double-step-down topology, and relates to the technical field of power electronic magnetic integration. The opening sides of the EE magnetic core are oppositely connected into a whole, the magnetic core vertical supporting arms on the two sides serve as wrapping posts to form an inductor L1 and an inductor L2 respectively, the magnetic core transverse connecting arm on the top, the magnetic core vertical supporting arm in the middle and the magnetic core transverse connecting arm at the bottom serve as a common magnetic circuit, and the additional magnetic core is a U-shaped magnetic core and is connected with the bottom of the EE magnetic core into a whole. The bottom ends of the three winding columns are horizontal sections to serve as winding columns to form an inductor L3, air gaps are formed in the centers of the three winding columns respectively, and air or low-magnetic-conductivity materials are added into the air gaps. A wrapping post and a related magnetic circuit are additionally arranged on the basis of an EE magnetic core, a structure with three wrapping posts and a plurality of common magnetic circuits is formed, better adaptability is achieved by adding air gaps, and reduction of the overall size, weight and loss of the inductor is facilitated.

Description

Technical Field

[0001] The 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 a bias inductor. 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 FIG. 1 , the bidirectional half bridge is replaced by two parallel complementary unidirectional switch 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 a better filtering effect.

[0004] However, the additional inductor will inevitably increase the size of the magnetic components. Traditional magnetic components are usually the most bulky and largest components in the power system. Magnetic components are an important component for transmitting and storing electrical energy. The quality of magnetic components directly affects the volume, efficiency, EMI and other performance of the converter, which is crucial for achieving voltage regulation of the power system. Therefore, in order to reduce the size and weight of magnetic components, improve power density and achieve better electromagnetic compatibility, it is urgent to propose a new magnetic core structure 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 a bias inductor, which adds an additional winding column and related magnetic circuit on the basis of the EE magnetic core to form a structure with three winding columns and multiple common magnetic circuits. Better adaptability is achieved by adding an air gap, which helps to reduce the overall volume, weight and loss of the inductor.

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

[0007] 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 arms of the magnetic core on both sides of the upper half of the magnetic core are respectively used as the first winding column and the second winding column, and the inductance L is formed by winding the coils. 1 and inductor L 2The top magnetic core transverse connecting arm, the middle magnetic core vertical arm and the bottom magnetic core transverse connecting arm of the upper part of the magnetic core are used 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 opening side is connected to the bottom two sides of the upper part of the magnetic core as a whole as the lower part of the magnetic core. The bottom end of the additional magnetic core is a horizontal section as the third winding column, and the inductance L is formed by winding the coil. 3 , 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 gaps.

[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 also has 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 the bottom thereof, forming a structure of three winding columns and multiple common magnetic circuits, and can realize three design schemes of uncoupled inductor, coupled two inductors or simultaneous coupling of three inductors by adding different air gaps, and has better adaptability to special circuit requirements, and 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 popularization 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 is a plan schematic diagram of solution 1 of the three-inductor integrated magnetic core structure of the present invention;

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

[0014] Figure 4 It is a plan schematic diagram of the second solution of the three-inductor integrated magnetic core structure of the present invention;

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

[0016] Figure 6 is a plan view of a third solution 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 pole; 2, second winding pole; 3, third winding pole; 4, first common magnetic circuit; 5, second common magnetic circuit; 6, third common magnetic circuit. DETAILED DESCRIPTION

[0019] The technical solution 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 of 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 Figure 2 to Figure 7 As shown, a three-inductor integrated magnetic core structure based on a dual-buck topology with a bias inductor includes a magnetic core body, wherein the magnetic core body is composed of an EE magnetic core and an additional magnetic core, wherein the opening 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, and the additional magnetic core is a U-shaped magnetic core and its opening 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.

[0021] The vertical arms of the magnetic core on both sides of the upper half of the magnetic core are used as the first winding column 1 and the second winding column 2, and form an inductance L by winding coils. 1 and inductor L 2 The top magnetic core transverse connecting arm, the middle magnetic core vertical arm and the bottom magnetic core transverse connecting arm in the upper half of the magnetic core are used 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 magnetic core is a horizontal section as the third winding column 3, and the inductance L is formed by winding the coil. 3 .

[0022] By adding different air gaps, there are three design schemes: uncoupled inductors, coupled inductors, or coupled inductors. The specific designs are as follows:

[0023] Solution 1

[0024] The core structure plan diagram of the design scheme is combined with Figure 2 As shown, air gaps are respectively opened at the center of the first winding post 1, the second winding post 2 and the third winding post 3, and air or a material with a magnetic permeability lower than that of a vacuum is added to the air gaps. At this time, the magnetic resistance of the air gaps is much greater than the magnetic resistance of other magnetic circuits, and the magnetic resistance of the first common magnetic circuit 4, the second common magnetic circuit 5 and the third common magnetic circuit 6 can be approximately zero. Inductance L 1Most of the magnetic flux generated only flows through the first winding column 1, the second common magnetic circuit 5, and the left half of the first common magnetic circuit 4 and the third common magnetic circuit 6. 2 Most of the magnetic flux generated only flows through the second winding column 2, the second common magnetic circuit 5, and the right half of the first common magnetic circuit 4 and the third common magnetic circuit 6. 3 Most of the magnetic flux generated only flows through the third winding column 3 and the third common magnetic circuit 6. It can be seen that the first common magnetic circuit 4 and the second common magnetic circuit 5 are inductors L 1 and inductor L 2 The third common magnetic circuit 6 is the inductor L 1 、Inductance L 2 and inductor L 3 public magnetic circuit.

[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, R 1 , R 1 , R 3 Represents the magnetic resistance of three air gaps, N 1 、N 2 、N 3 They represent the corresponding magnetomotive force, Φ 1 , Φ 2 , Φ 3 , Φ 4 , Φ 5 , Φ 6 They represent the magnetic flux of the corresponding branch, where Φ5=Φ1+Φ2, and the dotted line represents the flow direction of the magnetic flux of each winding. When the non-winding column does not have an air gap and only the air gap magnetic resistance is calculated, the magnetic flux generated by each winding only flows through the small loop where it is located, and there is no coupling between the inductors. When the magnetic flux flowing through a certain magnetic circuit is large, the winding method can be adjusted to offset part of the magnetic flux to reduce the volume of the magnetic core.

[0026] Solution 2

[0027] The core structure plan diagram of the design scheme is combined with Figure 4 As shown, air gaps are respectively provided at the center of the first winding post 1, the second winding post 2 and the third winding post 3, and an air gap is also provided at the center of the second common magnetic circuit 5, and air or a material with a magnetic permeability lower than that of a vacuum is added to the air gap. At this time, the magnetic resistance of the air gap is much greater than the magnetic resistance of 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. Inductance L 1 The generated magnetic flux not only flows through the second common magnetic circuit 5, but also part of the magnetic flux flows through the second winding column 2. 2 Similarly. But the inductor L 3Most of the generated magnetic flux 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 are the inductance L 1 and inductor L 2 The third common magnetic circuit 6 is the inductor L 1 、Inductance L 2 and inductor L 3 The common magnetic circuit. At this time, the inductance L 1 and inductor L 2 Coupling occurs, but the inductance L 3 Still independent.

[0028] Equivalent magnetic circuit combination Figure 5 As shown, R 0 , R 1 , R 1 , R 3 Respectively represent the magnetic resistance of the four air gaps, N 1 、N 2 、N 3 They represent the corresponding magnetomotive force, Φ 1 , Φ 2 , Φ 3 , Φ 4 , Φ 5 , Φ 6 They represent the magnetic flux of the corresponding branch, and the dotted line represents the direction of the magnetic flux of each winding. It can be seen from the direction of the dotted line that N 1 、N 2 The generated magnetic flux no longer flows only through each loop, indicating that the inductance L 1 and inductor L 2 Coupling occurs, and the appropriate coupling coefficient can be obtained by adjusting the air gap length to change the magnetic resistance.

[0029] Option 3

[0030] The core structure plan diagram of the design scheme is combined with Figure 6 As shown, air gaps are respectively provided at the center positions of the first winding post 1, the second winding post 2, the third winding post 3 and the second common magnetic circuit 5. At the same time, an air gap is also provided at the center position between the first winding post 1 and the second common magnetic circuit 5 or the center position between the second common magnetic circuit 5 and the second winding post 2 on the third common magnetic circuit 6, and air or a material with a magnetic permeability lower than that of vacuum is added to the air gap. At this time, the magnetic resistance of the air gap is much greater than the magnetic resistance of other magnetic circuits, and the magnetic resistance of the first common magnetic circuit 4 can be approximately zero. At this time, the magnetic flux generated by each inductor no longer produces a short-circuit effect due to the low magnetic resistance magnetic circuit, and the inductance L 1 、Inductance L 2 and inductor L 3 They are coupled to each other.

[0031] Equivalent magnetic circuit combination Figure 7 As shown, R 0 , R 1 , R 1 , R 3 , R 4 Respectively represent the magnetic resistance of the four air gaps, N 1 、N 2 、N 3 They represent the corresponding magnetomotive force, Φ 1 , Φ 2 , Φ 3 , Φ 4 , Φ 5 , Φ 6 The dotted lines represent the magnetic flux of the corresponding branches, and the dotted lines represent the direction of the magnetic flux of each winding. It can be seen from the direction of the dotted lines that the magnetic flux generated by each winding is no longer limited to a certain loop. 1 、Inductance L 2 and inductor L 3 Start coupling with each other.

[0032] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other forms of assembly without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0033] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description 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 may also be appropriately combined to form other implementation modes 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 a bias inductor, characterized in that: 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 transverse 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 are respectively used as a first winding column (1) and a second winding column (2), and are respectively wound with coils to form inductances L1 and L2, and the top magnetic core transverse connecting arm, the middle magnetic core vertical arm and the bottom magnetic core transverse connecting arm of the upper half of the magnetic core are sequentially used as a first common magnetic core. 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 a vacuum is added to the air gaps.

2. The three-inductor integrated core structure based on the dual-buck topology with bias inductor 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 the dual-buck topology with bias inductor 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 pole (1) and the second common magnetic circuit (5) or at a central position between the second common magnetic circuit (5) and the second winding pole (2).

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