Integrated adjustable leakage inductance matrix transformer and resonant converter

Abstract

The invention discloses an integrated adjustable leakage inductance matrix transformer and a resonant converter, and relates to the technical field of power electronics, the matrix transformer comprises an upper cover plate, a middle cover plate, a lower cover plate, a plurality of magnetic columns, a primary winding and a secondary winding; the magnetic columns are arranged between the upper-layer cover plate and the lower-layer cover plate, and each magnetic column is provided with an air gap; the middle-layer cover plate is arranged between the upper-layer cover plate and the lower-layer cover plate and penetrates through the air gaps; the primary winding is wound on the magnetic column close to one side of the upper-layer cover plate, and the secondary winding is wound on the magnetic column close to one side of the lower-layer cover plate; after electrification, a magnetic field generated by primary side current excitation forms a main magnetic flux loop through the upper-layer cover plate, the magnetic column, the lower-layer cover plate, the magnetic column and the upper-layer cover plate, and forms a leakage magnetic flux loop through the upper-layer cover plate, the magnetic column, the middle-layer cover plate, the magnetic column and the upper-layer cover plate; the size of the leakage inductance of the leakage magnetic flux loop is adjusted by adjusting the structural parameters and design conditions of the middle-layer cover plate. According to the invention, accurate control of the leakage inductance of the transformer and integration of the resonant inductor and the transformer are realized.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and particularly to an integrated matrix transformer with adjustable leakage inductance and a resonant converter. Background Art

[0002] The resonant cavity unit is an important component of a resonant DC converter, and the inductors and transformers (collectively referred to as magnetic components) in the resonant cavity unit are the core components. They generally occupy a relatively large proportion of the total volume of the converter and have an extremely important impact on the performance of the converter (such as efficiency and operating stability, etc.), so reasonable design of the magnetic components is required.

[0003] The design of magnetic components includes the design of a single magnetic component, such as the optimized design of a transformer or an inductor. In addition, it also includes the integrated design of multiple magnetic components, such as the integration of inductors and inductors, the integration of inductors and transformers, and the integration of transformers and transformers. Comparatively speaking, through the adoption of a reasonable integration method, the integrated design of multiple magnetic components can further enhance the advantages of the converter in terms of volume, weight, etc., and even can reduce losses to achieve the goal of improving the efficiency performance of the converter. Therefore, the research on magnetic integration technology has important practical significance and application value.

[0004] In recent years, due to the advantages demonstrated by resonant DC converters, many scholars have considered applying magnetic integration technology to such converters and have thus carried out extensive research in order to obtain better conversion performance. Some scholars have adopted the design of a matrix transformer structure for LLC resonant converters, and used the leakage inductance of the primary side of the transformer to equivalently replace the resonant inductance in the resonant cavity unit, achieving high-frequency and high-efficiency conversion.

[0005] However, for the magnetic integrated matrix transformer, due to the very good coupling performance between the primary winding and the secondary winding, the leakage inductance is very small, while the required design value of the actual leakage inductance is very large, and it is difficult to achieve the purpose of equivalently replacing the resonant inductance in the resonant cavity unit with the leakage inductance of the primary side of the transformer. Therefore, a reasonable method is needed to adjust the leakage inductance of this part to achieve the expected electrical performance.

[0006] Therefore, it is necessary to provide an integrated matrix transformer with adjustable leakage inductance to solve the above problems. Summary of the Invention

[0007] The purpose of the present application is to provide an integrated matrix transformer with adjustable leakage inductance and a resonant converter, which can achieve precise control of the magnitude of the transformer leakage inductance and realize the integration of the resonant inductance and the transformer.

[0008] To achieve the above purpose, the present application provides the following solutions:

[0009] In a first aspect, the present application provides an integrated adjustable leakage inductance matrix transformer, and the integrated adjustable leakage inductance matrix transformer includes: a cover plate, a magnetic core, and windings; the cover plate includes: an upper cover plate, a middle cover plate, and a lower cover plate; the magnetic core includes a plurality of magnetic posts; the windings include: a primary winding and a secondary winding;

[0010] Each of the magnetic posts is disposed between the upper cover plate and the lower cover plate, and each magnetic post is provided with an air gap;

[0011] The middle cover plate is disposed between the upper cover plate and the lower cover plate and passes through each of the air gaps;

[0012] The primary winding is wound around the magnetic posts on the side close to the upper cover plate, and the secondary winding is wound around the magnetic posts on the side close to the lower cover plate;

[0013] After being energized, the magnetic field generated by the excitation of the primary current forms a main magnetic flux loop via the upper cover plate - magnetic post - lower cover plate - magnetic post - upper cover plate, and the magnetic field generated by the excitation of the primary current forms a leakage magnetic flux loop via the upper cover plate - magnetic post - middle cover plate - magnetic post - upper cover plate;

[0014] Wherein, by adjusting the structural parameters and design conditions of the middle cover plate, the magnitude of the leakage inductance of the leakage magnetic flux loop is adjusted.

[0015] In an embodiment, the middle cover plate includes: a plurality of stacked laminations;

[0016] The structural parameters of the middle cover plate include: the number of laminations, the thickness of the laminations, the material of the laminations, and the size of the holes in the laminations;

[0017] The design conditions of the middle cover plate include: whether the laminations are perforated, whether the laminations are provided with planar air gaps, and the manner of providing planar air gaps in the laminations.

[0018] In an embodiment, each of the magnetic posts is separated into an upper magnetic post and a lower magnetic post by the air gap, and the upper magnetic post and the lower magnetic post are arranged in a butted manner.

[0019] In an embodiment, the magnetic core includes: a first magnetic post, a second magnetic post, a third magnetic post, and a fourth magnetic post, and the first magnetic post and the third magnetic post are diagonally arranged, and the second magnetic post and the fourth magnetic post are diagonally arranged.

[0020] In an embodiment, the primary winding starts from any one of the magnetic posts and is wound around all the magnetic posts in sequence;

[0021] Wherein, the winding directions of the primary winding on the first magnetic post and the third magnetic post are the same, the winding directions of the primary winding on the second magnetic post and the fourth magnetic post are the same, and the winding directions of the primary winding on the first magnetic post and the second magnetic post are different.

[0022] In one embodiment, the number of secondary windings is equal to the number of magnetic posts, and each of the secondary windings is wound around a corresponding magnetic post;

[0023] Among them, the winding directions of the secondary windings on the corresponding magnetic posts are the same.

[0024] In one embodiment, the shape of each magnetic post is a cylinder or a square post.

[0025] In one embodiment, the air gaps opened on each magnetic post are of equal size, and the effective cross-sectional areas of the magnetic posts are equal.

[0026] In one embodiment, the winding is a planar PCB winding, a copper litz wire winding or a copper enameled wire winding.

[0027] In a second aspect, the present application provides a resonant converter, which includes the matrix transformer with integrated adjustable leakage inductance, a full-bridge inverter circuit, an LLC resonant circuit, a rectifier and filter circuit, a sampling circuit, a micro-control unit, a driving circuit and an auxiliary power supply circuit;

[0028] The full-bridge inverter circuit, the LLC resonant circuit, the matrix transformer with integrated adjustable leakage inductance and the rectifier and filter circuit are connected in sequence to form a main power loop;

[0029] The sampling circuit, the micro-control unit and the driving circuit are connected in sequence. The sampling circuit is also connected to the rectifier and filter circuit, the driving circuit is also connected to the full-bridge inverter circuit, and the sampling circuit, the micro-control unit, the driving circuit are all connected to the auxiliary power supply circuit. The sampling circuit, the micro-control unit, the driving circuit and the auxiliary power supply circuit form an auxiliary control circuit.

[0030] According to the specific embodiments provided by the present application, the present application has the following technical effects:

[0031] The present application discloses a matrix transformer with integrated adjustable leakage inductance and a resonant converter. The middle cover plate of the matrix transformer is arranged between the upper and lower cover plates and passes through each air gap. After being energized, the magnetic field generated by the excitation of the primary current forms a main magnetic flux loop through the upper cover plate - magnetic post - lower cover plate - magnetic post - upper cover plate, and forms a leakage magnetic flux loop through the upper cover plate - magnetic post - middle cover plate - magnetic post - upper cover plate. By adjusting the structural parameters and design conditions of the middle cover plate, the size of the leakage inductance of the leakage magnetic flux loop is adjusted. The present application realizes precise control of the leakage inductance of the transformer by adding the middle cover plate and adjusting the structural parameters and design conditions of the middle cover plate. At the same time, it replaces the resonant inductor and integrates the resonant inductor and the transformer to achieve magnetic integration, thereby realizing a higher power density of the matrix transformer and improving the utilization rate of the magnetic core. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 The front view of the simulation model of the matrix transformer structure with integrated adjustable leakage inductance provided by an embodiment of the present application;

[0034] Figure 2 The side view of the simulation model of the matrix transformer structure with integrated adjustable leakage inductance provided by an embodiment of the present application;

[0035] Figure 3 The top view of the simulation model of the matrix transformer structure with integrated adjustable leakage inductance provided by an embodiment of the present application;

[0036] Figure 4 The schematic diagram of the magnetic flux loop in the side view direction of the matrix transformer with integrated adjustable leakage inductance provided by an embodiment of the present application;

[0037] Figure 5 The schematic diagram of the laminated structure provided by an embodiment of the present application;

[0038] Figure 6 The schematic diagram of the flow direction of the primary current of the matrix transformer with integrated adjustable leakage inductance provided by an embodiment of the present application;

[0039] Figure 7 A schematic diagram of a planar air gap of the middle cover plate of the matrix transformer with integrated adjustable leakage inductance provided by an embodiment of the present application;

[0040] Figure 8 The schematic diagram of the simulation result of the magnetic flux density corresponding to the upper cover plate of the matrix transformer with integrated adjustable leakage inductance provided by an embodiment of the present application;

[0041] Figure 9 The schematic diagram of the simulation result of the magnetic flux density corresponding to the middle cover plate of the matrix transformer with integrated adjustable leakage inductance provided by an embodiment of the present application;

[0042] Figure 10 The schematic diagram of the simulation results of the side magnetic flux density of the matrix transformer with integrated adjustable leakage inductance with and without the middle cover plate provided by an embodiment of the present application; wherein, (a) is the schematic diagram of the simulation result of the side magnetic flux density of the magnetic core without the middle cover plate, and (b) is the schematic diagram of the simulation result of the side magnetic flux density of the magnetic core with the middle cover plate;

[0043] Figure 11 Schematic diagrams of the lateral magnetic flux density simulation results of the magnetic core with the middle cover plate unperforated and perforated in the matrix transformer with integrated adjustable leakage inductance provided by an embodiment of the present application; wherein, (a) is the schematic diagram of the lateral magnetic flux density simulation result of the magnetic core with the middle cover plate unperforated, and (b) is the schematic diagram of the lateral magnetic flux density simulation result of the magnetic core with the middle cover plate perforated;

[0044] Figure 12 Schematic diagrams of the lateral magnetic flux density simulation results of the magnetic core when the middle cover plate of the matrix transformer with integrated adjustable leakage inductance has different perforation sizes provided by an embodiment of the present application; wherein, (a) is the schematic diagram of the lateral magnetic flux density simulation result of the magnetic core with a larger perforation in the middle cover plate, and (b) is the schematic diagram of the lateral magnetic flux density simulation result of the magnetic core with a reduced perforation in the middle cover plate;

[0045] Figure 13 Schematic diagrams of the lateral magnetic flux density simulation results of the magnetic core when the middle cover plate of the matrix transformer with integrated adjustable leakage inductance has different thicknesses provided by an embodiment of the present application; wherein, (a) is the schematic diagram of the lateral magnetic flux density simulation result of the magnetic core with a thinner middle cover plate, and (b) is the schematic diagram of the lateral magnetic flux density simulation result of the magnetic core with an increased thickness of the middle cover plate;

[0046] Figure 14 Schematic diagrams of the lateral magnetic flux density simulation results of the magnetic core when the middle cover plate of the matrix transformer with integrated adjustable leakage inductance is made of different materials provided by an embodiment of the present application; wherein, (a) is the schematic diagram of the lateral magnetic flux density simulation result of the magnetic core when the material of the middle cover plate is a magnetic powder core, and (b) is the schematic diagram of the lateral magnetic flux density simulation result of the magnetic core when the material of the middle cover plate is a ferrite;

[0047] Figure 15 Schematic diagrams of the lateral magnetic flux density simulation results of the magnetic core when the matrix transformer with integrated adjustable leakage inductance has no planar air gap and has a planar air gap provided by an embodiment of the present application; wherein, (a) is the schematic diagram of the lateral magnetic flux density simulation result of the magnetic core when the middle cover plate has no planar air gap, and (b) is the schematic diagram of the lateral magnetic flux density simulation result of the magnetic core when the middle cover plate has a planar air gap;

[0048] Figure 16 Schematic diagram of the circuit structure of the resonant converter provided by an embodiment of the present application;

[0049] Figure 17 Schematic diagram of the circuit principle of the resonant converter provided by an embodiment of the present application.

[0050] Reference numerals:

[0051] Upper cover plate 1, middle cover plate 2, lower cover plate 3, primary winding 4, secondary winding 5, first magnetic post A, second magnetic post B, third magnetic post C, fourth magnetic post D. Detailed Implementation Manner

[0052] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0053] To make the above objects, features, and advantages of the present application more apparent and understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0054] In an exemplary embodiment, as Figures 1 - 3 shown, an integrated adjustable leakage inductance matrix transformer is provided, including: a cover plate, a magnetic core, and windings; the cover plate includes: an upper cover plate 1, a middle cover plate 2, and a lower cover plate 3; the magnetic core includes a plurality of magnetic columns; the windings include: a primary winding 4 and a secondary winding 5. Figure 1 Among them, the orange rings together form the primary winding 4, and each blue ring is a secondary winding 5.

[0055] Each magnetic column is arranged between the upper cover plate 1 and the lower cover plate 3, and each magnetic column is provided with an air gap.

[0056] The middle cover plate 2 is arranged between the upper cover plate 1 and the lower cover plate 3 and passes through each air gap.

[0057] The primary winding 4 is wound around the magnetic columns on the side close to the upper cover plate 1, and the secondary winding is wound around the magnetic columns on the side close to the lower cover plate 3.

[0058] After being energized, the magnetic field generated by the excitation of the primary current forms a main magnetic flux loop through the upper cover plate 1 - magnetic column - lower cover plate 3 - magnetic column - upper cover plate 1, and the magnetic field generated by the excitation of the primary current forms a leakage magnetic flux loop through the upper cover plate 1 - magnetic column - middle cover plate 2 - magnetic column - upper cover plate 1.

[0059] Specifically, as observed from the side view of the matrix transformer, the direction of the magnetic flux is as Figure 4 shown, the main magnetic flux loop is the magnetic flux loop corresponding to the black arrow in Figure 4 , and the leakage magnetic flux loop is the magnetic flux loop corresponding to the orange arrow in Figure 4 . Among them, by adjusting the structural parameters and design conditions of the middle cover plate 2, the magnitude of the leakage inductance of the leakage magnetic flux loop can be adjusted.

[0060] As an alternative implementation manner, the middle cover plate 2 includes: a plurality of stacked laminations. Among them, the schematic diagram of the lamination structure is as Figure 5 shown.

[0061] The structural parameters of the middle-layer cover plate 2 include: the number of laminations, the thickness of the laminations, the material of the laminations, and the size of the openings in the laminations. The design conditions of the middle-layer cover plate 2 include: whether the laminations have openings, whether the laminations have planar air gaps, and the way of forming planar air gaps in the laminations.

[0062] Specifically, the leakage flux path does not pass through the secondary winding and will not couple with the secondary windings on the four magnetic posts. This part of the magnetic flux becomes leakage inductance. Therefore, by adjusting the number, thickness, material of the laminations that make up the middle-layer cover plate 2, whether the laminations have openings, the size of the openings in the laminations, whether the laminations have planar air gaps, the way of forming planar air gaps in the laminations, and the way of forming planar slots in the laminations, precise control of the leakage inductance of the matrix transformer can be achieved. At the same time, the leakage inductance corresponding to the matrix transformer replaces the resonant inductance, thus integrating the traditional resonant inductance and transformer together, realizing magnetic integration, achieving a higher power density of the matrix transformer, and improving the utilization rate of the magnetic core.

[0063] For a resonant converter with an integrated adjustable leakage inductance matrix transformer as the core device, through the adjustment design of the middle-layer cover plate 2, precise control of the leakage inductance value can be achieved to meet the gain characteristics of the resonant converter under different working conditions. Among them, the specific adjustment methods include:

[0064] 1) Adjusting the thickness. The middle-layer cover plate 2 is composed of stacked laminations. It can be considered that the laminations are relatively thin standard parts. When it is necessary to increase the thickness of the middle-layer cover plate 2, multiple laminations are stacked. Magnetic flux can be analogized to current, and the key factor affecting the size of magnetic flux is magnetic resistance. Generally speaking, the magnetic resistance of the main magnetic flux path is much smaller than that of the leakage magnetic flux path, which is also the reason why the main magnetic flux is much larger than the leakage magnetic flux. That is R is the magnetic resistance; S is the cross-sectional area of the magnetic flux path; μ is the magnetic permeability; increasing the number and thickness will increase the cross-sectional area of the leakage magnetic flux path and reduce the magnetic resistance, thereby increasing the leakage magnetic flux and leakage inductance. Vice versa.

[0065] 2) The material of the middle-layer cover plate 2: The magnetic permeability of the material directly affects the size of the magnetic resistance. Materials with a large magnetic permeability μ have a low magnetic resistance, and materials with a small magnetic permeability have a high magnetic resistance. The basis for forming a new leakage magnetic flux path by the middle-layer cover plate 2 is that the material of the middle-layer cover plate 2 itself has a high magnetic permeability. When the magnetic resistance of the middle-layer cover plate 2 becomes smaller, the leakage magnetic flux will increase accordingly.

[0066] 3) Opening holes. The middle cover plate 2 itself does not have holes. When it is necessary to increase the leakage magnetic flux, holes can be opened on the plate to increase the magnetic resistance of the main magnetic flux circuit, thereby increasing the leakage magnetic flux. Among them, the main magnetic flux circuit and the leakage magnetic flux circuit are orthogonal in space. When opening holes in the middle cover plate 2 based on the center position of the magnetic column, the magnetic resistance of the main magnetic flux circuit will increase because the magnetic permeability of the main magnetic flux circuit is reduced. While the magnetic permeability of the leakage magnetic flux circuit remains unchanged, more magnetic fields will preferentially close through the magnetic conductive plate.

[0067] 4) Opening planar grooves. Opening planar grooves on the middle cover plate 2 will directly truncate the leakage magnetic flux circuit on the middle cover plate 2, reduce the magnitude of the leakage magnetic flux, and significantly reduce the leakage magnetic flux compared to opening holes.

[0068] 5) In addition, the magnitude of the leakage inductance is also related to the number of turns of the primary winding 4. The more turns of the primary winding 4 wound on the four magnetic columns, the more leakage inductance the matrix transformer will increase.

[0069] As an alternative implementation, each magnetic column is separated into an upper magnetic column and a lower magnetic column by an air gap, and the upper magnetic column and the lower magnetic column are arranged in a butted manner.

[0070] As an alternative implementation, as Figure 3 shown, the magnetic core includes: the first magnetic column A, the second magnetic column B, the third magnetic column C, and the fourth magnetic column D, and the first magnetic column A and the third magnetic column C are arranged diagonally, and the second magnetic column B and the fourth magnetic column D are arranged diagonally. Figure 3 Only the first magnetic column A, the second magnetic column B, the third magnetic column C, and the fourth magnetic column D are shown, and the upper cover plate 1 and the middle cover plate 2 are omitted.

[0071] As an alternative implementation, the primary winding 4 starts from any magnetic column and is wound around all magnetic columns in sequence. The total number of turns is N p turns.

[0072] Among them, the winding directions of the primary winding 4 on the first magnetic column A and the third magnetic column C are the same, the winding directions of the primary winding 4 on the second magnetic column B and the fourth magnetic column D are the same, and the winding directions of the primary winding 4 on the first magnetic column A and the second magnetic column B are different. The primary winding 4 is wound between the upper cover plate 1 and the middle cover plate 2.

[0073] As an alternative implementation, the number of secondary windings is equal to the number of magnetic columns, and each secondary winding is wound around the corresponding magnetic column respectively.

[0074] Among them, the winding directions of each secondary winding on the corresponding magnetic column are all the same. Each secondary winding is wound between the middle cover plate 2 and the lower cover plate 3.

[0075] Specifically, in this embodiment, the number of secondary windings is 4, and one secondary winding is wound on each magnetic column. The number of turns of the secondary winding wound on the first magnetic column A is N s1 turns, the number of turns of the secondary winding wound on the second magnetic column B is N s2 turns, the number of turns of the secondary winding wound on the third magnetic column C is N s3 turns, and the number of turns of the secondary winding wound on the fourth magnetic column D is N s4 turns. The specific number of turns to be wound is determined according to the design requirements of the transformer. After the primary winding 4 and the secondary winding are wound on each magnetic column, each magnetic column constitutes an element transformer of the matrix transformer. Therefore, the matrix transformer in this example is composed of four element transformers.

[0076] As an alternative embodiment, the shape of each magnetic column is a cylinder or a square column.

[0077] As an alternative embodiment, the air gaps opened on each magnetic column are of equal size, and the effective cross-sectional areas of each magnetic column are equal.

[0078] Specifically, the four magnetic columns are evenly distributed between the upper cover plate 1 and the lower cover plate 3, forming a symmetric structure at the four corners. The upper cover plate 1, the middle cover plate 2, and the lower cover plate 3 constitute the upper, middle, and lower three layers of the magnetic integrated matrix transformer. Among them, the upper cover plate 1 and the lower cover plate 3 are made of ferrite materials and form the main magnetic flux loop with the four magnetic columns; the middle cover plate 2 adopts a laminated structure and is made of magnetic powder core or ferrite material to form a leakage magnetic flux loop for leakage inductance adjustment. Among them, the four magnetic columns are buckled together with a gap (i.e., an air gap).

[0079] As an alternative embodiment, the winding is a planar PCB winding, a copper litz wire winding, or a copper enameled wire winding.

[0080] Next, taking the four magnetic columns shown as an example, the matrix transformer with integrated adjustable leakage inductance in this application will be further elaborated. Figure 3 As shown in the figure, the magnetic core includes: the first magnetic column A, the second magnetic column B, the third magnetic column C, and the fourth magnetic column D. According to the principle of the transformer, current is applied to the primary side of the transformer, the primary winding 4 generates magnetic flux, and the secondary winding is used to induce magnetic flux. After being energized, the direction of the primary current is as shown in

[0081] As shown in Figure 3 , the red arrow direction in Figure 6 is the direction of the primary current. The current enters from the first magnetic column A at the lower right corner and winds around counterclockwise; then enters the second magnetic column B and winds around clockwise; then enters the third magnetic column C and winds around counterclockwise; then enters the fourth magnetic column D and winds around clockwise. Figure 6 Figure 6 Figure 6 The current enters from the first magnetic column A at the lower right corner and winds around counterclockwise; then enters the second magnetic column B and winds around clockwise; then enters the third magnetic column C and winds around counterclockwise; then enters the fourth magnetic column D and winds around clockwise.

[0082] It can be seen that for the primary winding 4, although it is a single winding, different winding directions will change the direction of the current, and thus change the direction of the magnetic flux. The magnetic flux directions of the first magnetic column A and the third magnetic column C are the same, the magnetic flux directions of the second magnetic column B and the fourth magnetic column D are the same, and the magnetic flux directions of the first magnetic column A and the third magnetic column C are different.

[0083] The direction of the magnetic flux observed from the side view is as Figure 4 shown. The laminated core at the center of the matrix transformer is equivalent to adding a loop of leakage magnetic flux outside the main magnetic flux loop. After being energized, the magnetic field generated by the excitation of the primary current will form a leakage magnetic flux loop of transformer cover - magnetic column - middle cover plate 2 of the transformer - magnetic column - transformer cover outside the main magnetic flux loop of transformer cover - magnetic column - transformer cover - magnetic column - transformer cover.

[0084] The magnetic field generated by the excitation of the primary current will form a leakage magnetic flux loop between the upper cover plate 1 - magnetic column - middle cover plate 2 - magnetic column - upper cover plate 1 outside the main magnetic flux loop formed by the upper cover plate 1 - magnetic column - lower cover plate 3 - magnetic column - upper cover plate 1. Since the leakage magnetic flux loop does not pass through the secondary winding, it will not be coupled with the secondary windings on the four magnetic columns. Therefore, by adjusting the number, thickness, material of the laminated cores constituting the middle cover plate 2, whether the laminated cores are perforated, the size of the perforations in the laminated cores, whether the laminated cores have planar air gaps, the way of forming the planar air gaps in the laminated cores, and the way of forming planar slots in the laminated cores, precise control of the leakage inductance of the matrix transformer can be achieved to replace the resonant inductor, thereby realizing magnetic integration.

[0085] As an optional implementation manner, a way of forming a planar air gap in the middle cover plate 2 is as Figure 7 shown.

[0086] Furthermore, in order to verify the magnetic flux distribution of the matrix transformer with integrated adjustable leakage inductance of the present application, a magnetic integrated matrix transformer for LLC resonant converter leakage inductance adjustment (i.e., the matrix transformer with integrated adjustable leakage inductance of the present application) is simulated through the simulation tool Maxwell 3D.

[0087] Figure 8 is a schematic diagram of the simulation result of the magnetic flux density corresponding to the upper cover plate 1, Figure 9 is a schematic diagram of the simulation result of the magnetic flux density corresponding to the middle cover plate 2. Combining Figure 8 and Figure 9 it can be seen from the magnetic flux distribution that the main magnetic flux is concentrated between the four magnetic columns, forming a closed magnetic flux loop.

[0088] Based on Figure 4 the perspective of the side view of the magnetic flux, corresponding finite element simulation is carried out, and the simulation result of the lateral magnetic flux density of the magnetic core as shown in Figure 10 is obtained. Figure 10The different colors in it reflect the magnitude of the magnetic flux. The red color indicates a large magnetic flux, while the blue color indicates a small magnetic flux. In Figure 10 Figure (a) in it shows the simulation result of the lateral magnetic flux density of the magnetic core without adding the middle cover plate 2 (i.e., with air as the air gap). The magnetic flux is distributed in the left and right magnetic columns, forming a closed loop, which is shown as the colored area; the blue area is the air domain, reflecting the magnitude of the leakage magnetic flux, and at this time the leakage magnetic flux is very small; Figure 10 Figure (b) in it shows the simulation result of the lateral magnetic flux density of the magnetic core with the middle cover plate 2 added (i.e., the matrix transformer with integrated adjustable leakage inductance in this application). Obviously, there is a leakage magnetic flux forming a closed loop through the middle cover plate 2, increasing the leakage magnetic flux. From Figure 10 the lateral distribution of the magnetic flux in it, it can be seen that by adding the middle cover plate 2 of the transformer, a closed leakage magnetic flux loop can be formed outside the main magnetic flux loop.

[0089] Holes are made in the middle cover plate 2 of the matrix transformer with integrated adjustable leakage inductance, and corresponding finite element simulations are carried out to obtain the schematic diagram of the simulation result of the lateral magnetic flux density of the magnetic core as shown in Figure 11 . Figure 11 Figure (a) in it is the schematic diagram of the magnetic flux distribution of the magnetic core with only the middle cover plate 2 added (without holes). At this time, part of the leakage magnetic flux forms a loop; Figure 11 Figure (b) in it is the schematic diagram of the magnetic flux distribution of the magnetic core with holes in the middle cover plate 2. It can be seen that the magnetic flux of the main magnetic flux loop decreases, and the magnetic flux of the leakage magnetic flux loop increases significantly, and the leakage inductance increases significantly. From Figure 11 the lateral distribution of the magnetic flux in it, it can be seen that by making holes in the middle cover plate 2 of the transformer, the magnitude of the leakage magnetic flux can be adjusted.

[0090] Holes of different sizes are made in the middle cover plate 2 of the matrix transformer with integrated adjustable leakage inductance, and corresponding finite element simulations are carried out to obtain the schematic diagram of the simulation result of the lateral magnetic flux density of the magnetic core as shown in Figure 12 . Figure 12 Figure (a) in it is the schematic diagram of the simulation result of the lateral magnetic flux density of the magnetic core with larger holes in the middle cover plate 2. At this time, the weakening effect on the main magnetic flux and the enhancement effect on the leakage magnetic flux are both obvious; Figure 12 Figure (b) in it is the schematic diagram of the simulation result of the lateral magnetic flux density of the magnetic core with the holes in the middle cover plate 2 reduced. When the holes are reduced, the main magnetic flux will increase slightly, and the leakage magnetic flux will decrease slightly. From Figure 12 the lateral distribution of the magnetic flux in it, it can be seen that by changing the size of the holes, the magnitude of the leakage magnetic flux can be adjusted.

[0091] The thickness of the middle cover plate 2 of the matrix transformer with integrated adjustable leakage inductance is adjusted, and corresponding finite element simulations are carried out to obtain the schematic diagram of the simulation result of the lateral magnetic flux density as shown in Figure 13 . Figure 13Figure (a) in [reference] is a schematic diagram of the simulation result of the lateral magnetic flux density of the middle-layer cover plate 2 when it is thinner. At this time, part of the magnetic flux passes through the middle-layer cover plate 2 to form a leakage magnetic flux loop. Figure 13 Figure (b) in [reference] is a schematic diagram of the simulation result of the lateral magnetic flux density of the middle-layer cover plate 2 when it is thickened. At this time, there is a more obvious leakage magnetic flux loop. From Figure 13 the lateral distribution of the magnetic flux in [reference], it can be seen that by changing the thickness of the middle-layer cover plate 2, the magnitude of the leakage magnetic flux can be adjusted.

[0092] Replace the material of the middle-layer cover plate 2 of the matrix transformer with integrated adjustable leakage inductance, and perform corresponding finite element simulations to obtain the Figure 14 schematic diagram of the simulation result of the lateral magnetic flux density of the magnetic core as shown. Figure 14 In Figure (a) in [reference], the material of the middle-layer cover plate 2 is magnetic powder core, Figure 14 in Figure (b) in [reference], the material of the middle-layer cover plate 2 is ferrite, and the magnetic permeability of ferrite is much greater than that of magnetic powder core. Therefore, in Figure 14 Figure (b) in [reference], it can be seen that a large amount of magnetic flux passes through the middle-layer cover plate 2 to form a closed leakage magnetic flux loop, and the magnetic flux entering the upper main magnetic flux loop is significantly reduced. From Figure 14 the lateral distribution of the magnetic flux in [reference], it can be seen that by changing the material of the middle-layer cover plate 2, the magnitude of the leakage magnetic flux can be adjusted.

[0093] Open a planar air gap in the middle-layer cover plate 2 (made of ferrite) of the matrix transformer with integrated adjustable leakage inductance, and perform corresponding finite element simulations to obtain the Figure 15 schematic diagram of the simulation result of the lateral magnetic flux density as shown. Figure 15 Figure (a) in [reference] is a schematic diagram of the simulation result of the lateral magnetic flux density of the middle-layer cover plate 2 without opening a planar air gap, Figure 15 Figure (b) in [reference] is the simulation result of the middle-layer cover plate 2 with a planar air gap opened. The planar air gap truncates the leakage magnetic flux loop, thus greatly reducing the magnitude of the leakage magnetic flux. Figure 15 In Figure (b) in [reference], the truncation of the magnetic circuit can be clearly seen. From Figure 15 the lateral distribution of the magnetic flux in [reference], it can be seen that by increasing the internal air gap of the middle-layer cover plate 2, the magnitude of the leakage magnetic flux can be adjusted.

[0094] Based on the same inventive concept, an embodiment of the present application also provides a resonant converter including the matrix transformer with integrated adjustable leakage inductance involved above. The implementation solution provided by this resonant converter to solve the problem is similar to the implementation solution described in the above method. Therefore, the specific limitations in the following embodiments of the resonant converter can refer to the limitations on the matrix transformer with integrated adjustable leakage inductance in the above text, and will not be elaborated here.

[0095] In an exemplary embodiment, as Figure 16As shown, a resonant converter is provided, which includes a matrix transformer with integrated adjustable leakage inductance, a full-bridge inverter circuit, an LLC resonant circuit, a rectifier filter circuit, a sampling circuit, a micro-control unit, a driving circuit, and an auxiliary power supply circuit.

[0096] Among them, the full-bridge inverter circuit, the LLC resonant circuit, the matrix transformer with integrated adjustable leakage inductance, and the rectifier filter circuit are connected in sequence to form a main power loop (i.e., the main circuit in Figure 16 ); the sampling circuit, the micro-control unit, and the driving circuit are connected in sequence. The sampling circuit is also connected to the rectifier filter circuit, and the driving circuit is also connected to the full-bridge inverter circuit. Moreover, the sampling circuit, the micro-control unit, and the driving circuit are all connected to the auxiliary power supply circuit. The sampling circuit, the micro-control unit, the driving circuit, and the auxiliary power supply circuit form an auxiliary control circuit (corresponding to Figure 16 the control circuit in

[0097] Specifically, the full-bridge inverter circuit is used to convert the input direct current into an alternating square wave. The full-bridge inverter circuit is composed of power MOS tubes.

[0098] The LLC resonant circuit serves as the main power transmission circuit and adjusts the output gain by utilizing the gain characteristics of the LLC circuit.

[0099] The matrix transformer with integrated adjustable leakage inductance is the main magnetic element, generating a magnetic field that is the basis for power transmission and achieving electrical isolation.

[0100] The rectifier filter circuit is used to convert alternating current into direct current for output.

[0101] The sampling circuit is used to collect the voltage signal and current signal of the circuit during operation and provide parameters for the control circuit. The sampling circuit is composed of power MOS tubes.

[0102] The micro-control unit is used to generate corresponding control signals according to the real-time sampling results (voltage signal and current signal), adjust the operating frequency, and achieve gain adjustment.

[0103] The driving circuit is used to provide driving signals for the power MOS tubes of the inverter circuit and the rectifier circuit to work.

[0104] The power supply circuit is used to supply power to some components in the circuit. It should be noted that the resonant converter in this embodiment can also be in other forms, which is not limited here.

[0105] The leakage inductance of the matrix transformer with integrated adjustable leakage inductance in this application can be used as the resonant inductance of the resonant converter, and thus incorporated into the design scheme of the resonant converter. The schematic diagram of the resonant converter is as Figure 17 shown, using the multi-input and multi-output structure of the matrix transformer (the matrix transformer is an integration of each sub-transformer, and each sub-transformer has one input and one output. InFigure 17 The structure shown is called parallel input and series output, that is, the input sides of all sub-units are in parallel and the output sides are in series). Figure 17 In, H Bus+ represents the positive pole of the high-voltage side input bus; H Bus- represents the negative pole of the high-voltage side input bus; LBus+ represents the positive pole of the low-voltage side output bus; L Bus- represents the negative pole of the high-voltage side output bus; 1#, 2#, 3#, 4# are the four element transformers of the matrix transformer.

[0106] Taking a 12kW resonant converter as an example, the matrix transformer with adjustable integrated leakage inductance is designed. First, determine the design requirements such as the input, output, and power of the system, as shown in Table 1, and calculate the resonant network parameters such as the voltage gain, turns ratio, and resonant inductance of the transformer, as shown in Table 2.

[0107] Table 1 Specific parameter table of the resonant converter

[0108] Parameter Input voltage range Input rated voltage Output voltage Full load current Rated load Operating frequency Value 520V - 560V 540V 270V 33.75A 8Ω 100kHz

[0109] Table 2 Specific parameter table of the resonant network

[0110] Parameter Transformer turns ratio n Quality factor Q Inductance ratio Resonant capacitor Cr Resonant inductor Lr Magnetizing inductor Lm Value 8 0.4 4 153.6nF 16.49μF 56.96μF

[0111] According to the specific parameters of the resonant network in Table 2 and the design method of the above matrix transformer with adjustable integrated leakage inductance, a specific embodiment of the integrated adjustable leakage inductance matrix transformer is obtained.

[0112] Compared with the design results of the traditional non-integrated method, this application has obvious advantages in terms of volume; compared with the planar transformer PQ65 designed using the AP method, the volume is reduced, meeting the design expectations; under different working conditions and design requirements, the resonant network parameters will change greatly. The matrix transformer designed in this embodiment has a more definite adjustment relationship and a better adjustment method for resonant parameters such as leakage inductance, and has broad practical value.

[0113] Advantages of this application:

[0114] This application designs an adjustable integrated leakage inductance for the traditional matrix transformer. By adding the middle cover plate of the transformer, outside the main magnetic flux loop, a leakage magnetic flux loop of upper cover plate - magnetic column - middle cover plate - magnetic column - upper cover plate is formed. Since the leakage magnetic flux loop does not pass through the secondary winding and will not be coupled with the secondary windings on the four peripheral magnetic columns, the size of the leakage inductance of the transformer can be precisely controlled by adjusting the structural parameters and design conditions of the middle cover plate of the transformer. At the same time, it replaces the resonant inductance, thus integrating the resonant inductance and the transformer to achieve magnetic integration, enabling a higher power density of the matrix transformer and improving the utilization rate of the magnetic core.

[0115] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0116] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0117] Specific examples are used in this article to elaborate on the principle and implementation manner of this application. The description of the above embodiments is only used to help understand the device of this application and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. An integrated matrix transformer with adjustable leakage inductance, characterized in that, The matrix transformer integrated with adjustable leakage inductance includes: a cover plate, a magnetic core, and windings; the cover plate includes: an upper cover plate, a middle cover plate, and a lower cover plate; the magnetic core includes a plurality of magnetic columns; the windings include: a primary winding and a secondary winding; Each of the magnetic columns is disposed between the upper cover plate and the lower cover plate, and each magnetic column is provided with an air gap; The middle cover plate is disposed between the upper cover plate and the lower cover plate and passes through each of the air gaps; The primary winding is wound around the magnetic columns on the side close to the upper cover plate, and the secondary winding is wound around the magnetic columns on the side close to the lower cover plate; After being powered on, the magnetic field generated by the excitation of the primary current forms a main magnetic flux loop through the upper cover plate - magnetic column - lower cover plate - magnetic column - upper cover plate, and the magnetic field generated by the excitation of the primary current forms a leakage magnetic flux loop through the upper cover plate - magnetic column - middle cover plate - magnetic column - upper cover plate; Among them, by adjusting the structural parameters and design conditions of the middle cover plate, the magnitude of the leakage inductance of the leakage magnetic flux loop is adjusted.

2. The integrated adjustable leakage inductance matrix transformer according to claim 1, wherein The middle cover plate includes: a plurality of stacked laminations; The structural parameters of the middle cover plate include: the number of laminations, the thickness of the laminations, the material of the laminations, and the size of the holes in the laminations; The design conditions of the middle cover plate include: whether the laminations are perforated, whether the laminations are provided with planar air gaps, and the way of providing planar air gaps in the laminations.

3. The matrix transformer with integrated adjustable leakage inductance according to claim 1, characterized in that, Each of the magnetic columns is separated into an upper magnetic column and a lower magnetic column through the air gap, and the upper magnetic column and the lower magnetic column are arranged in a butted manner.

4. The matrix transformer with integrated adjustable leakage inductance according to claim 3, characterized in that, The magnetic core includes: a first magnetic column, a second magnetic column, a third magnetic column, and a fourth magnetic column, and the first magnetic column and the third magnetic column are arranged diagonally, and the second magnetic column and the fourth magnetic column are arranged diagonally.

5. The integrated adjustable leakage inductance matrix transformer according to claim 4, wherein The primary winding starts from any one of the magnetic columns and is wound around all the magnetic columns in sequence; Among them, the winding directions of the primary winding on the first magnetic column and the third magnetic column are the same, the winding directions of the primary winding on the second magnetic column and the fourth magnetic column are the same, and the winding directions of the primary winding on the first magnetic column and the second magnetic column are different.

6. The matrix transformer with integrated adjustable leakage inductance according to claim 4, characterized in that, The number of the secondary windings is equal to the number of the magnetic columns, and each of the secondary windings is wound around the corresponding magnetic column respectively; Among them, the winding directions of each of the secondary windings on the corresponding magnetic columns are all the same.

7. The matrix transformer with integrated adjustable leakage inductance according to claim 4, wherein The shape of each of the magnetic columns is a cylinder or a square column.

8. The matrix transformer with integrated adjustable leakage inductance according to claim 4, characterized in that, The sizes of the air gaps opened on each of the magnetic columns are equal, and the effective cross-sectional areas of each of the magnetic columns are equal.

9. The matrix transformer with integrated adjustable leakage inductance according to claim 1, wherein The windings are planar PCB windings, copper litz wire windings, or copper enameled wire windings.

10. A resonant converter, characterized in that, The resonant converter includes the matrix transformer integrated with adjustable leakage inductance according to any one of claims 1 - 9, a full-bridge inverter circuit, an LLC resonant circuit, a rectifier and filter circuit, a sampling circuit, a micro control unit, a drive circuit, and an auxiliary power supply circuit; The full-bridge inverter circuit, the LLC resonant circuit, the matrix transformer integrated with adjustable leakage inductance, and the rectifier and filter circuit are connected in sequence to form a main power loop; The sampling circuit, the micro control unit and the driving circuit are connected in sequence. The sampling circuit is also connected to the rectifying and filtering circuit, and the driving circuit is also connected to the full-bridge inverter circuit. Moreover, the sampling circuit, the micro control unit and the driving circuit are all connected to the auxiliary power supply circuit, and the sampling circuit, the micro control unit, the driving circuit and the auxiliary power supply circuit form an auxiliary control circuit.

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