A three-dimensional symmetrical structure magnetic integrated high-frequency transformer for a three-phase converter

Abstract

The utility model discloses a kind of three-dimensional symmetry structure magnetic integrated high-frequency transformers for three-phase converter, including magnetic core assembly and winding, the magnetic core assembly has three-column three-dimensional symmetry structure, its top and bottom are all equilateral triangle and parallel alignment, two triangles are connected by three columns located on three corners, three columns are perpendicular to two triangle planes, the cross-sectional area and side length of equilateral triangle of top and bottom are same, the cross-sectional area and length of three columns are same;The magnetic core assembly is one of integrated structure, split type structure, three-frame type magnetic core combination structure, the winding is respectively equipped with one primary winding and one secondary winding on each column;Primary winding and secondary winding are all equipped with terminal. The utility model can effectively improve the power density of three-phase converter, reduce energy loss and improve interphase current uniformity, to improve the stability and efficiency of three-phase converter system.

Description

Technical Field

[0001] This utility model relates to the field of magnetic integration technology in power electronic power converters, specifically a three-dimensional symmetrical magnetic integrated high-frequency transformer for three-phase converters. Background Technology

[0002] Three-phase converters, with their high power output, low output current ripple and good heat distribution characteristics, have been widely used in distributed power systems, charging piles, energy storage systems and other fields, and have become key equipment in the field of power electronic conversion.

[0003] However, in the design and application of transformers, the core component of three-phase converters, the current implementation schemes for multiphase transformers are significantly limited by existing magnetic core models and structural designs. Currently, the industry generally adopts magnetic integration schemes with three independent transformers or multi-column planar structures. For example, the 2022 master's thesis of Xi'an University of Technology, "Research on Magnetic Integration Based on Three-Phase LLC Resonant Converter," uses a three-column EC70 planar magnetic core. Invention patent with publication number CN113809904B, a matrix transformer based on topological magnetic integration of LLC resonant converter also adopts a planar magnetic integration design. These planar structures or independent transformer schemes often result in a large overall converter size, high energy loss, and poor interphase current sharing due to uneven interphase coupling, affecting system stability and efficiency.

[0004] In addition, although some technologies have attempted to adopt a three-dimensional structure (such as the "super material-saving transformer" with publication number CN2340072Y), it is only suitable for power frequency scenarios and cannot meet the requirements of high frequency conversion.

[0005] In summary, existing transformer solutions are difficult to adapt to the requirements of miniaturization, high efficiency, and high consistency of three-phase converters under high-frequency operating conditions. Therefore, the development of a novel three-dimensional symmetrical structure magnetically integrated high-frequency transformer suitable for three-phase converters to solve problems such as size, loss, and current sharing has become an urgent need for the current industry development. Utility Model Content

[0006] The purpose of this invention is to provide a three-dimensional symmetrical magnetic integrated high-frequency transformer for three-phase converters. It features a reasonable three-dimensional symmetrical structure design, high power density, low loss, and good inter-phase current sharing. In particular, in three-phase LLC resonant converters, it can be equivalent to the series and parallel resonant inductances of the resonant converter by adjusting the excitation inductance and leakage inductance, thereby reducing the number of main circuit components and fault points, lowering costs, and being suitable for high-frequency operating conditions of 10KHz-2MHz. This invention solves the problems in the prior art.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A three-dimensional symmetrical magnetically integrated high-frequency transformer for a three-phase converter, comprising:

[0009] The magnetic core assembly is composed of high-frequency magnetically conductive material and has a magnetic core structure with two equilateral triangles and three magnetic core pillars. The two equilateral triangles are divided into a top equilateral triangle and a bottom equilateral triangle and are aligned in parallel. The top equilateral triangle and the bottom equilateral triangle are connected by three magnetic core pillars located at the three corners. The three magnetic core pillars are perpendicular to the plane of the top equilateral triangle and the bottom equilateral triangle.

[0010] The top and bottom equilateral triangles of the magnetic core assembly have the same cross-sectional area and side length; the three magnetic core pillars have the same cross-sectional area and length; the cross-sectional area of ​​the magnetic core pillars is 50%-400% of the cross-sectional area of ​​the top or bottom equilateral triangle, which is determined by the designer according to the specific design requirements.

[0011] Each core column of the magnetic core assembly is equipped with a primary winding and a secondary winding.

[0012] Both the primary and secondary windings are equipped with terminals.

[0013] The magnetic core assembly can be one of an integral structure, a split structure, or a three-frame magnetic core combination structure;

[0014] In the integrated structure, the magnetic core assembly is an independent whole, and its structure includes two parallel and aligned top equilateral triangles and bottom equilateral triangles, as well as three magnetic core pillars that are vertically connected to the top equilateral triangles and bottom equilateral triangles.

[0015] In the aforementioned split structure, the magnetic core assembly is composed of two identical split triangular magnetic core units joined together; each split triangular magnetic core unit comprises an equilateral triangular yoke and a column extending perpendicularly from the three corners of the triangle; the end faces of the corresponding columns of the two split triangular magnetic core units are joined together to form a complete magnetic core assembly; and the length of the two columns can be adjusted according to the placement position of the air gap, which can be either 50% of the total length or other proportions.

[0016] In the aforementioned three-frame magnetic core assembly structure, the magnetic core assembly is composed of three identical frame-shaped magnetic cores arranged end-to-end. The three identical frame-shaped magnetic cores are arranged in an equilateral triangle in space, forming a closed three-dimensional frame with their ends adjacent to each other. The included angle between the axes of adjacent frame-shaped magnetic cores is 60°. Each frame-shaped magnetic core is an independent UU-type, UI-type, or square magnetic core. After the three frame-shaped magnetic cores are combined in space, they form a magnetic core assembly. The top and bottom outlines of the magnetic core assembly are both equilateral triangles, and its three magnetic core pillars are located at the three corners of the equilateral triangle and are perpendicular to the plane of the triangle.

[0017] Each magnetic core column of the magnetic core assembly is physically composed of two independent column components belonging to different frame-type magnetic cores, arranged side by side.

[0018] The three frame-shaped magnetic cores are of the same size, which makes the magnetic core assembly exhibit rotational symmetry about its central axis.

[0019] Preferably, the frame-type magnetic cores in the three-frame magnetic core assembly structure can be formed by stacking single or multiple magnetic cores to adjust the cross-sectional area of ​​a single magnetic core, and the gaps when they are stacked can naturally form anti-saturation gaps.

[0020] Preferably, the cross-sectional shape of the magnetic core column and the top and bottom equilateral triangles of the magnetic core assembly is one of a circle, a square, a rectangle, or a triangle.

[0021] It is worth noting that this design can adapt to different installation spaces and structural requirements, enhancing the flexibility of the magnetic core in various application scenarios. At the same time, the reasonable cross-sectional shape helps to optimize the magnetic circuit distribution, reduce magnetic resistance, reduce magnetic core loss, and improve the overall efficiency of the transformer.

[0022] Preferably, the magnetic core column of the magnetic core assembly can be either open or closed with an air gap, and the air gap length is 0 mm to 10 mm; the coupling degree between the primary winding and the secondary winding is between 0% and 100%; this is used to control the permeability and inductance of the magnetic material.

[0023] The air gap refers to a section of non-magnetic material on the core column of the magnetic core assembly, used to control the permeability and inductance of the magnetic material.

[0024] It is worth noting that by setting an air gap and adjusting its length, the excitation inductance of the magnetic core assembly can be flexibly adjusted, making it equivalent to the parallel resonant inductance in a three-phase LLC resonant converter, which can meet different resonant frequency and power requirements. In addition, the air gap can also effectively prevent magnetic core saturation and ensure that the transformer operates stably under high current conditions.

[0025] Preferably, the coupling degree between the primary winding and the secondary winding is adjustable, ranging from 0% to 100%. The primary winding and the secondary winding can be completely separated or completely coupled. When fully coupled, the primary winding and the secondary winding are wound in a sandwich structure.

[0026] It is worth noting that the sandwich structure can make the coupling between the primary and secondary windings tighter, minimize leakage inductance, and improve energy transmission efficiency. This structure can also effectively reduce electromagnetic interference between windings, improve the electromagnetic compatibility of the transformer, and ensure the stable operation of the circuit.

[0027] It is worth noting that the adjustable coupling degree allows the transformer to flexibly adjust the leakage inductance. When applied to a three-phase LLC resonant converter, the leakage inductance can be equivalent to a series resonant inductor, thus adapting to different resonant circuit parameters. At the same time, the coupling degree can be optimized according to the actual operating conditions to reduce energy loss and improve energy transmission efficiency.

[0028] Preferably, the material of the magnetic core assembly is one of ferrite, iron-silicon-aluminum, iron-nickel-molybdenum, nanocrystal, ultracrystalline, or amorphous.

[0029] It is worth noting that the selection of various high-frequency magnetic materials enables the core assembly to adapt to different operating frequencies (10kHz-2MHz) and power requirements. It can still maintain low magnetic loss under high-frequency conditions, improving the efficiency of the transformer. At the same time, the characteristics of different materials can meet diverse application scenarios, enhancing the applicability of the transformer.

[0030] Preferably, the primary winding and the secondary winding are wound with enameled wire or insulated wire, and the conductor material is copper or aluminum.

[0031] Preferably, the primary and secondary windings have no more than four layers. The primary and secondary windings are mounted on the column via an insulating frame.

[0032] It is worth noting that the use of enameled or insulated wire ensures the insulation performance of the winding. Copper and aluminum materials have good conductivity, which can reduce the resistance loss of the winding. The number of layers does not exceed 4, which can effectively reduce the additional losses caused by the skin effect and proximity effect, improve the conductivity efficiency of the winding, and thus improve the overall performance of the transformer.

[0033] Preferably, the transformer is suitable for a three-phase converter with a switching frequency of 10kHz to 2MHz. The three-phase converter has three primary windings and three secondary windings, and both the primary and secondary windings can be connected in a delta or star configuration.

[0034] It is worth noting that the wide switching frequency range and flexible winding connection methods enable this transformer to be compatible with various types of three-phase converters, expanding its application areas. It can be widely used in distributed power systems, charging piles, energy storage systems and other scenarios. At the same time, it meets the requirements of three-phase converters with different topologies, improving the equipment's versatility and interchangeability.

[0035] Preferably, when the transformer is applied to a three-phase LLC resonant converter, its magnetizing inductance is equivalent to a parallel resonant inductance, and its leakage inductance is equivalent to a series resonant inductance.

[0036] It is worth noting that this equivalent effect allows the transformer to replace the independent resonant inductor in a three-phase LLC resonant converter, reducing the number of main circuit components, lowering circuit complexity and fault points, while saving installation space, increasing power density, and reducing overall cost.

[0037] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0038] 1. This utility model adopts a three-column three-dimensional symmetrical magnetic integrated structure, which integrates the functions of three independent transformers into one. Through the symmetrical design of the equilateral triangles at the top and bottom of the magnetic core and the vertical distribution of the three magnetic core columns at the three corners, the redundant space of the traditional multi-transformer combination is reduced. At the same time, the cross-sectional area of ​​the frame-type magnetic core can be adjusted by stacking single or multiple sets, avoiding the lateral expansion of the planar structure, significantly reducing the overall volume of the converter, increasing the power density, and solving the problem of the large size of the traditional multi-transformer.

[0039] 2. The magnetic core assembly uses high-frequency magnetic materials such as ferrite and nanocrystals. The excitation inductance can be adjusted by adjusting the air gap (0-10mm) of the magnetic core column, which can reduce high-frequency hysteresis loss. The leakage inductance can be adjusted by adjusting the coupling degree of the coil.

[0040] 3. The magnetic core assembly is symmetrically distributed in an equilateral triangle with consistent magnetic circuit parameters. Each magnetic core column is independently equipped with primary and secondary windings, and the winding parameters (number of turns, number of layers, and material) are uniform, ensuring symmetrical three-phase current paths. The three-dimensional structure reduces interphase electromagnetic interference, which can improve the current symmetry and solve the problem of poor current sharing caused by uneven coupling in traditional solutions.

[0041] 4. The core material and structural design support switching frequencies of 10kHz-2MHz, breaking through the limitation of existing three-dimensional structures that are only applicable to power frequency. The excitation inductance and leakage inductance can be equivalent to the parallel / series resonant inductance of a three-phase LLC resonant converter, eliminating the need for independent resonant components and meeting the requirements of miniaturization and integration of high-frequency conversion systems. Attached Figure Description

[0042] Figure 1This is a three-dimensional structural diagram of the magnetic core assembly of this utility model;

[0043] Figure 2 This is a schematic diagram of the transformer structure of this utility model;

[0044] Figure 3 This is a schematic diagram of the split structure of the magnetic core assembly of this utility model;

[0045] Figure 4 This is a schematic diagram of the three frame-type magnetic core structures of the magnetic core assembly of this utility model;

[0046] Figure 5 This is a schematic diagram of a transformer according to an embodiment of the present invention;

[0047] Figure 6 This is a front view schematic diagram of the transformer according to an embodiment of the present utility model;

[0048] Figure 7 This is a schematic diagram of the LLC resonant converter structure used in the transformer application of this utility model.

[0049] In the diagram: 1. Magnetic core assembly; 101. Top equilateral triangle; 102. Bottom equilateral triangle; 103. Magnetic core column; 104. Split magnetic core; 105. Frame-type magnetic core; 2. Winding; 3. Primary winding; 4. Secondary winding; 5. Terminal. Detailed Implementation

[0050] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0051] To address the issues of large size, high loss, poor interphase current sharing in existing technologies, and the fact that existing three-dimensional structure solutions are only suitable for power frequency applications and cannot meet the requirements of high-frequency conversion, the following technical solution is proposed. Please refer to [link / reference]. Figures 1-6 ;

[0052] A three-dimensional symmetrical magnetically integrated high-frequency transformer for a three-phase converter, comprising:

[0053] Magnetic core assembly 1: It is composed of high-frequency magnetic conductive material and has a magnetic core structure with two equilateral triangles and three magnetic core pillars. The two equilateral triangles are divided into a top equilateral triangle 101 and a bottom equilateral triangle 102, which are parallel and aligned. The top equilateral triangle 101 and the bottom equilateral triangle 102 are connected by three magnetic core pillars 103 located at the three corners. The three magnetic core pillars 103 are perpendicular to the plane of the two equilateral triangles.

[0054] The top equilateral triangle 101 and the bottom equilateral triangle 102 of the magnetic core assembly 1 have the same cross-sectional area and side length, and the three magnetic core pillars 103 have the same cross-sectional area and length.

[0055] Each magnetic core column 103 is provided with a primary winding 3 and a secondary winding 4;

[0056] Terminal 5 is installed on both the primary winding 3 and the secondary winding 4;

[0057] The magnetic core assembly 1 can be one of the following: an integral structure, a separable structure, or a multi-three-frame magnetic core combination structure. It can be formed by stacking single or multiple magnetic cores to adjust the cross-sectional area of ​​the magnetic core assembly.

[0058] Please see Figures 1-6 A further solution based on this embodiment is that the cross-sectional shape of the top equilateral triangle 101, the bottom equilateral triangle 102, and the magnetic core column 103 of the magnetic core assembly 1 is one of a circle, a square, a rectangle, or a triangle.

[0059] Please see Figures 1-6 A further solution based on this embodiment is: the column of the magnetic core column 103 is provided with an air gap, the length of which is 0mm to 10mm.

[0060] Please see Figures 1-6 A further solution based on this embodiment is that the coupling degree of the primary winding 3 and the secondary winding 4 is adjustable, and the coupling degree is between 0% and 100%.

[0061] Please see Figures 1-6 A further solution based on this embodiment is that the material of the magnetic core assembly 1 is one of ferrite, iron-silicon-aluminum, iron-nickel-molybdenum, nanocrystal, ultracrystalline or amorphous.

[0062] Please see Figures 1-6 A further solution based on this embodiment is: the primary winding 3 and the secondary winding 4 are wound with enameled wire or insulated wire, and the conductor material is copper or aluminum.

[0063] Please see Figures 1-6 A further solution based on this embodiment is: the transformer is suitable for a three-phase converter with a switching frequency of 10kHz to 2MHz. The three-phase converter has three primary windings 3 and three secondary windings 4, and both the primary and secondary windings can be connected in a delta or star configuration.

[0064] Please see Figures 1-6 A further solution based on this embodiment is: when the transformer is applied to a three-phase LLC resonant converter, its magnetizing inductance is equivalent to a parallel resonant inductance, and its leakage inductance is equivalent to a series resonant inductance.

[0065] In this embodiment 1, the magnetic core assembly 1 is an integral structure, which is an independent whole; its structure includes two parallel and aligned top equilateral triangles 101 and bottom equilateral triangles 102, and three magnetic core pillars 103 that vertically connect the top equilateral triangles 101 and bottom equilateral triangles 102.

[0066] The effective cross-sectional area of ​​the magnetic core column 103 of the magnetic core assembly 1 is 184 mm², and the length is 15 mm. The effective cross-sectional area of ​​the top equilateral triangle 101 and the bottom equilateral triangle 102 is 92 mm², and the side length is 22.5 mm.

[0067] The magnetic core assembly 1 is made of DMR44 type ferrite material and is manufactured using integrated molding and vacuum sintering technology.

[0068] The converter operates at a frequency of 100kHz, with three phases interleaved at 120°, an output of 3600W, an input of 270V, and an output of 28V. The primary winding 3 and the secondary winding 4 are both star-connected. The primary winding has 6 turns, and the secondary winding has 2 turns. The primary winding is made of 1mm² enameled wire, and the secondary winding is made of 4 strands of 2.5mm² enameled wire wound in a sandwich structure.

[0069] Tests showed that the overall volume of the transformer was reduced by 35% compared to the traditional three independent transformer scheme; in terms of loss control, under 100kHz operating conditions, the core loss (iron loss) was less than 30W, the winding loss (copper loss) was less than 20W, and the total loss accounted for less than 1.4% of the output power; in terms of phase-to-phase current sharing, the deviation of the three-phase output current was less than 1.5%, which is far superior to the traditional planar magnetic integration scheme (current sharing is usually less than 95%).

[0070] In this embodiment 2, the magnetic core assembly 1 is composed of two identical split triangular magnetic core units 104 joined together; each split triangular magnetic core unit 104 includes an equilateral triangular yoke and a column extending vertically from the three corners of the triangle; the end faces of the corresponding columns of the two split triangular magnetic core units 104 are joined together to form a complete magnetic core assembly 1.

[0071] The magnetic core unit 104 of the magnetic core assembly 1 has an effective cross-sectional area of ​​5670 mm², a column length of 1500 mm, and an effective cross-sectional area of ​​2835 mm² and a side length of 2100 mm for the equilateral triangular yoke.

[0072] The magnetic core assembly 1 uses LP9 type ferrite material as the magnetic material, and the two separate triangular magnetic core units 104 are manufactured by mold integration and vacuum sintering technology.

[0073] The converter operates at a frequency of 20kHz, with three phases interleaved at 120°, an output of 75kW, an input of 540V, and an output of 1000V. The primary winding 3 and the secondary winding 4 are both star-connected. The primary winding has 14 turns, and the secondary winding has 32 turns. A sandwich structure is used for winding.

[0074] Testing revealed that the overall volume of the transformer was reduced by 29% compared to the traditional three independent transformer scheme. Regarding loss control, at 20kHz, core loss (iron loss) was less than 1000W, winding loss (copper loss) was less than 500W, and total loss accounted for less than 2% of the output power. In terms of phase-to-phase current sharing, the deviation of the three-phase output current was less than 2%, far superior to the traditional planar magnetic integration scheme. This embodiment 3 designs a three-dimensional symmetrical magnetic integrated high-frequency transformer to match a 15kW three-phase LLC resonant converter. The core parameters of this converter are as follows: the operating frequency is fixed at 180kHz; the three-phase drive pulses use 120° offset control to achieve three-phase balance; the input is three-phase 380V AC power, which is rectified and filtered before being connected to the primary side of the transformer; the output needs to stably provide 400V DC voltage and 40A DC current to meet the power supply requirements of medium-to-high power energy storage or charging pile systems.

[0075] In this embodiment, the magnetic core assembly 1 uses LP9 type ferrite material as the magnetic material, and the structure adopts a "three-frame magnetic core combination structure". The specific selection and assembly method are as follows: Each frame magnetic core 105 is formed by splicing the corresponding magnetic yoke parts of two UY6480 magnetic cores to form a closed magnetic circuit, ensuring that each frame magnetic core 105 has an independent and complete magnetic conduction path; the effective cross-sectional area of ​​the UY6480 ferrite magnetic core is 288mm², and the length of a single frame magnetic circuit is 206mm, which can meet the low hysteresis loss requirements under 180kHz high-frequency conditions;

[0076] Next, the three frame-shaped magnetic cores 105 are arranged symmetrically with their ends adjacent to each other, and the included angle between two frame-shaped magnetic cores 105 is 60°. The top magnetic yokes of the three frame-shaped magnetic cores 105 form a top equilateral triangle 101, and the bottom magnetic yokes of the three frame-shaped magnetic cores 105 form a bottom equilateral triangle 102. The pillars of the three frame-shaped magnetic cores 105 are located at the three vertices of the equilateral triangles and are perpendicular to the planes of the top equilateral triangle 101 and the bottom equilateral triangle 102. After assembly, the three frame-shaped magnetic cores 105 are adjacent to each other to form the three magnetic core pillars 103 of the magnetic core assembly 1.

[0077] The edges of the magnetic yoke are fixed with the aid of high-temperature resistant insulating adhesive, which not only ensures the stability of the three-dimensional structure, but also avoids magnetic interference between adjacent frames. The three frame-shaped magnetic cores are the same size, so that the magnetic core assembly 1 as a whole exhibits rotational symmetry about its central axis.

[0078] In terms of winding design, to match the turns ratio and resonance parameter requirements of the LLC resonant converter, the specific parameters and processes are as follows: the number of turns of the primary winding 3 is 12 turns, and the number of turns of the secondary winding 4 is 13 turns. The voltage conversion of "input three-phase 380V → output 400V" is achieved through this turns ratio.

[0079] It is wound with multi-strand soft copper enameled wire with a cross-sectional area of ​​3mm², and the number of layers in each phase winding is controlled to 2 layers, which can effectively reduce the skin effect and proximity effect at 180kHz high frequency and reduce copper loss.

[0080] The windings are mounted on the column through a high-temperature resistant insulating frame, and the primary windings and secondary windings are separated by a 5mm gap. This gap design can precisely control the leakage inductance of each phase winding to 30μH. This leakage inductance is directly equivalent to the series resonant inductance of a three-phase LLC resonant converter, eliminating the need for additional independent series resonant components and reducing the number of main circuit components and fault points.

[0081] To adapt to the parallel resonance requirements of the three-phase LLC resonant converter, this embodiment further adapts to the parallel resonant inductor, specifically designed as follows: A 465μH high-frequency inductor (made of ferrite core to ensure matching with the high-frequency characteristics of the transformer) is connected in parallel across the primary winding of each frame. This parallel inductor serves as the parallel resonant inductor of the three-phase LLC resonant converter, working in synergy with the magnetizing inductance of the primary winding to achieve resonant cavity parameter matching at a frequency of 180kHz.

[0082] By combining a 30μH leakage inductance with a 465μH parallel inductance, the converter meets the zero-voltage turn-on condition of the switching transistors across the entire load range, reducing switching losses and ensuring a conversion efficiency of no less than 95% under 15kW output conditions. During circuit connection, the primary windings of the three frames are connected in a delta topology via terminals (to meet the balanced requirements of a three-phase 380V input), and the three secondary windings are also connected in a star topology via terminals (to reduce output voltage ripple). The terminals are made of copper and tin-plated to ensure stable current transmission and corrosion resistance.

[0083] After actual testing, the three-dimensional symmetrical structure magnetic integrated high-frequency transformer for three-phase converter in this embodiment meets the following performance indicators after assembly: In terms of power density, due to the three-frame three-dimensional symmetrical layout, the overall volume of the transformer is reduced by 40% compared with the traditional three independent transformer scheme, which is suitable for the miniaturization requirements of 15KW converter.

[0084] In terms of loss control, under 180kHz operating conditions, the core loss (iron loss) is less than 80W, the winding loss (copper loss) is less than 120W, and the total loss accounts for less than 1.3% of the output power;

[0085] In terms of phase-to-phase current sharing, the deviation of the three-phase output current is less than 2%, which is far superior to the traditional planar magnetic integration scheme (current sharing is usually less than 95%), ensuring the stable operation of the three-phase LLC converter.

[0086] In addition, it should be noted that the magnetic core assembly 1 of this utility model is not only applicable to high-frequency transformers.

[0087] In the output inductor of a three-phase converter, the core requirements of "reducing size, reducing high-frequency loss, and ensuring uniform phase current" are also faced: When the output inductor adopts the structure described in core assembly 1, a coil is wound on each core column 3, and two terminals are connected on each coil to form the output inductor of the three-phase converter. The three-phase symmetrical closed magnetic circuit structure helps to resist bias magnetism and improve the uniformity of phase current. The vertical layout of the columns can reduce the installation space occupied. The adjustable air gap characteristic (0mm-10mm) can flexibly match the inductance requirements of different loads. The high-frequency magnetic material can also be adapted to the switching frequency range of 10kHz-2MHz of the three-phase converter.

[0088] Working Principle: This utility model, "A Three-Dimensional Symmetrical Structure Magnetic Integrated High-Frequency Transformer for Three-Phase Converters," operates as follows: The core assembly 1 is composed of high-frequency magnetically conductive material and has a core structure consisting of two equilateral triangles and three core pillars. The two equilateral triangles are divided into a top equilateral triangle 101 and a bottom equilateral triangle 102, which are parallel and aligned. The top equilateral triangle 101 and the bottom equilateral triangle 102 are connected by three core pillars 103 located at the three corners. The three core pillars 103 are perpendicular to the plane of the two equilateral triangles. The cross-sectional area and side length of the top equilateral triangle 101 and the bottom equilateral triangle 102 of the core assembly 1 are the same, and the cross-sectional area and length of the three core pillars 103 are the same. The cross-sectional shape is one of a circle, square, rectangle, or triangle. The cross-sectional area of ​​the core pillar 103 is 50%-400% of the cross-sectional area of ​​the top / bottom triangle. The magnetic core assembly 1 can be one of an integrated structure, a split structure, or a three-frame magnetic core combination structure; the cross-sectional area of ​​the three-frame magnetic core combination structure can be adjusted by stacking single or multiple sets; it is made of one of the following materials: ferrite, iron-silicon-aluminum, iron-nickel-molybdenum, nanocrystalline, ultracrystalline, or amorphous, to provide a stable magnetic circuit foundation for the entire device;

[0089] Each core post 103 is equipped with a primary winding 3 and a secondary winding 4. Both the primary and secondary windings are wound with enameled or insulated wire of copper or aluminum. Terminals 5 are installed on both the primary and secondary windings 3 and 4 for connection to external circuits. During operation, the primary winding 3 is connected to the input side of the three-phase converter, and the secondary winding 4 is connected to the output side. The primary winding 3 transfers electrical energy to the secondary winding 4 through the magnetic coupling of the core assembly 1. The cross-sections of the equilateral triangle 101 at the top, the equilateral triangle core at the bottom, and the post 103 of the core assembly 1 can be designed as circular, square, rectangular, or triangular, depending on requirements. An air gap (0mm to 10mm in length) on the core post 3 is used to adjust the permeability and inductance parameters of the core assembly 1.

[0090] The coupling degree of the primary winding 3 and the secondary winding 4 can be adjusted between 0% and 100%. This transformer is suitable for three-phase converters with switching frequencies from 10kHz to 2MHz. The three-phase converter has three primary windings 3 and three secondary windings 4, and the three primary windings 3 and three secondary windings 4 can be connected in delta or star configurations to adapt to different circuit topology requirements.

[0091] When applied to a three-phase LLC resonant converter, the magnetizing inductance of the core assembly 1 is equivalent to a parallel resonant inductor, and the leakage inductance of the core assembly 1 is equivalent to a series resonant inductor, participating in the operation of the resonant circuit to achieve efficient energy conversion. Through the above structure and operation mode, the device size is effectively reduced, losses are reduced, and the interphase current sharing is improved to meet the requirements of high-frequency conversion.

[0092] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0093] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A three-dimensional symmetrical magnetically integrated high-frequency transformer for a three-phase converter, characterized in that, include: The magnetic core assembly (1) is composed of high-frequency magnetic conductive material and has a magnetic core structure with two equilateral triangles and three magnetic core pillars. The two equilateral triangles are divided into a top equilateral triangle (101) and a bottom equilateral triangle (102) and are aligned in parallel. The top equilateral triangle (101) and the bottom equilateral triangle (102) are connected by three magnetic core pillars (103) located at the three corners. The three magnetic core pillars (103) are perpendicular to the plane of the top equilateral triangle (101) and the bottom equilateral triangle (102). Each core post (103) of the winding (2) and the core assembly (1) is equipped with a primary winding (3) and a secondary winding (4); both the primary winding (3) and the secondary winding (4) are equipped with terminals (5).

2. The three-dimensional symmetrical magnetically integrated high-frequency transformer for a three-phase converter as described in claim 1, characterized in that, The top equilateral triangle (101) and the bottom equilateral triangle (102) of the magnetic core assembly (1) have the same cross-sectional area and side length, and the three magnetic core pillars (103) have the same cross-sectional area and length; the cross-sectional shape is one of circle, square, rectangle or triangle; the cross-sectional area of ​​the magnetic core pillar (103) is 50%-400% of the cross-sectional area of ​​the top / bottom triangle.

3. The three-dimensional symmetrical magnetic integrated high-frequency transformer for a three-phase converter as described in claim 1, characterized in that, The magnetic core assembly (1) is one of an integrated structure, a split structure, or a three-frame magnetic core combination structure; In the integrated structure, the magnetic core assembly (1) is an independent whole, and its structure includes two parallel and aligned top equilateral triangles (101) and bottom equilateral triangles (102), as well as three magnetic core pillars (103) that vertically connect the top equilateral triangle (101) and bottom equilateral triangle (102). In the split structure described above, the magnetic core assembly (1) is composed of two identical split triangular magnetic core units (104) joined together; each of the split triangular magnetic core units (104) includes an equilateral triangular yoke and a column extending perpendicularly from the three corners of the triangle; the end faces of the corresponding columns of the two split triangular magnetic core units (104) are joined together to form a complete magnetic core assembly (1). In the aforementioned three-frame magnetic core assembly structure, the magnetic core assembly (1) is composed of three identical frame magnetic cores (105) arranged end to end. The three identical frame magnetic cores (105) are arranged in an equilateral triangle in space, forming a closed three-dimensional frame. The included angle between the axes of adjacent frame magnetic cores (105) is 60°. Each frame magnetic core (105) is an independent UU-type, UI-type, or square magnetic core. After the three frame magnetic cores (105) are combined in space, they constitute the magnetic core assembly (1). The top and bottom outlines of the magnetic core assembly (1) are both equilateral triangles. Its three magnetic core pillars (103) are located at the three corners of the equilateral triangle and are perpendicular to the plane of the triangle. Each magnetic core column (103) of the magnetic core assembly (1) is physically composed of two independent column components belonging to different frame-type magnetic cores (105) arranged side by side; The three frame-shaped magnetic cores (105) are of the same size, so that the magnetic core assembly (1) as a whole exhibits rotational symmetry about its central axis.

4. A three-dimensional symmetrical magnetically integrated high-frequency transformer for a three-phase converter as described in claim 1, characterized in that, The high-frequency magnetic material of the magnetic core assembly (1) is one of ferrite, iron-silicon-aluminum, iron-nickel-molybdenum, nanocrystal, ultracrystalline or amorphous.

5. A three-dimensional symmetrical magnetically integrated high-frequency transformer for a three-phase converter as described in claim 1, characterized in that, The transformer is suitable for a three-phase converter with a switching frequency of 10kHz-2MHz. The three-phase converter has three primary windings (3) and three secondary windings (4), and both the primary and secondary windings can be connected in a delta or star configuration. The primary windings (3) and secondary windings (4) are wound with enameled wire or insulated wire, and the conductor material is copper or aluminum.

6. A three-dimensional symmetrical magnetically integrated high-frequency transformer for a three-phase converter as described in claim 1, characterized in that, The magnetic core assembly (1) can have an air gap or no air gap on the magnetic core column (103), and the air gap length is 0 mm to 10 mm; the coupling degree between the primary winding (3) and the secondary winding (4) is between 0% and 100%. The air gap refers to a section of non-magnetic material on the magnetic core column (103) of the magnetic core assembly (1), which is used to control the permeability and inductance of the magnetic material.

7. A three-dimensional symmetrical magnetically integrated high-frequency transformer for a three-phase converter as described in claim 1, characterized in that, When the three-dimensional symmetrical structure magnetic integrated high-frequency transformer is applied to a three-phase LLC resonant converter, the excitation inductance of the transformer is adjusted by adjusting the air gap length of the magnetic core column (103) in the magnetic core assembly (1), and the leakage inductance of the transformer is adjusted by adjusting the coupling degree between the primary winding (3) and the secondary winding (4). In the resonant circuit of the three-phase LLC resonant converter, the magnetizing inductor is equivalent to the parallel resonant inductor required by the resonant circuit, and the leakage inductance is equivalent to the series resonant inductor required by the resonant circuit.

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