CN212258791U

CN212258791U - LLC resonant converter

Info

Publication number: CN212258791U
Application number: CN202020965159.8U
Authority: CN
Inventors: 栗亮; 马红中; 严琼珍
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 2020-06-01
Filing date: 2020-06-01
Publication date: 2020-12-29
Anticipated expiration: 2030-06-01

Abstract

An LLC resonant converter comprises a transformer winding and a resonant coil, wherein the transformer winding comprises a primary winding and a secondary winding which are wound along a first axis simultaneously, and at least one resonant coil passes through a coil central opening part of the transformer winding and the outer side of the transformer winding and is wound along a second axis which is orthogonal to the first axis. Through the utility model discloses the scheme can effectively solve the high loss problem that magnetic element integrated and bring, and transformer winding and resonance coil can share same magnetic core, do benefit to and realize that LLC resonant converter compromises high power and miniaturized design.

Description

LLC resonant converter

Technical Field

The utility model belongs to the technical field of the power electronic converter, especially, relate to an effectively solve LLC resonant converter of the integrated problem of magnetic element.

Background

LLC resonant converters are superior to conventional series resonant converters and parallel resonant converters in terms of their high efficiency and high power density, and thus are widely used in various switching power supplies and the like. The LLC resonant converter comprises magnetic elements such as a transformer winding and a resonant coil, the development of the design of the magnetic elements tends to be high frequency, the high frequency can greatly shorten the volume of the LLC resonant converter, and the power density is improved. However, since the high frequency also has a problem of high loss, the reduction of loss becomes a significant challenge in designing a magnetic element.

In the prior art, in order to reduce high loss, at least one shared magnetic core is added between a transformer winding and a resonant coil to form bypass magnetic flux, the transformer winding and the resonant coil need to respectively keep a certain safety distance from the shared magnetic core, but an LLC resonant converter is large in size and does not meet the ever-increasing miniaturization requirement.

Disclosure of Invention

An object of the utility model is to provide a LLC resonant converter to solve loss and the volume problem that magnetic element integrates among the prior art.

For solving the prior art problem, the utility model provides a LLC resonant converter, including transformer winding and resonance coil, transformer winding includes simultaneously along the winding primary winding of first axis and secondary, resonance coil at least one, through transformer winding's coil central opening portion reaches transformer winding's the outside, along with first axis is the winding of second axis of quadrature direction.

Optionally, the LLC resonant converter has a first core and a second core, which are connected up and down along the coil central opening portion and the outside to form a closed magnetic circuit.

Optionally, the first magnetic core and the second magnetic core are two C-shaped magnetic cores arranged oppositely, and inner magnetic columns of the C-shaped magnetic cores are connected up and down along the central opening of the coil.

Alternatively, the resonance coil includes a first resonance coil and a second resonance coil connected in series or in parallel with each other, both of the first resonance coil and the second resonance coil passing through the coil center opening portion of the transformer winding and an outer side of the transformer winding, the first resonance coil being wound along a second axis orthogonal to the first axis, the second resonance coil being wound along a third axis orthogonal to the first axis.

Optionally, the primary winding and the secondary winding are each covered by an insulator.

Compared with the prior art, the beneficial effects of the utility model reside in that, because the winding direction of transformer winding and two magnetic fluxes of resonance coil are each other for the quadrature, can not influence the production magnetic leakage flux each other, consequently do not have among the prior art because of the magnetic leakage flux leads to the high loss problem that magnetomotive force increases and bring to need not add the magnetic core in addition, realized the miniaturization of product volume. Furthermore, the winding turns of the resonance coil are easier to adjust, so that the inductance of the resonance coil is more flexibly controlled, and the application range is wider.

Drawings

Fig. 1 is a topological structure equivalent diagram of the LLC resonant converter of the present invention;

fig. 2 is an exploded schematic diagram of a resonant network of the LLC resonant converter of the present invention;

fig. 3 is a schematic perspective view of a resonant network of the LLC resonant converter of the present invention;

fig. 4 is a front view of the resonant network of the LLC resonant converter of the present invention;

FIG. 5 is a sectional view A-A of the front view of FIG. 4;

fig. 6 is a front view of the resonant network of the LLC resonant converter of the present invention;

fig. 7 is a sectional view B-B in front view of fig. 6.

Detailed Description

The following further describes embodiments of the present invention with reference to the accompanying drawings.

Fig. 1 is a topological structure equivalent diagram of the LLC resonant converter of the present invention. Fig. 2 is an exploded schematic diagram of the resonant network of the LLC resonant converter of the present invention. Fig. 3 is a schematic perspective view of the resonant network of the LLC resonant converter of the present invention. Fig. 4 is a front view of the resonant network of the LLC resonant converter of the present invention. Fig. 5 is a sectional view a-a in the front view shown in fig. 4. Fig. 6 is a front view of the resonant network of the LLC resonant converter of the present invention. Fig. 7 is a sectional view B-B in front view of fig. 6.

Fig. 1 shows a topological equivalent diagram of the LLC resonant converter of the present invention, the LLC resonant converter generally consists of three parts, i.e. a square wave generating circuit, a resonant network and an output circuit, wherein the transformer winding T and the resonant coil Lr in the resonant network of fig. 1 are the key points for the design of the magnetic elements.

As shown in fig. 2 to 3, the LLC resonant converter according to the present embodiment includes the primary winding 1, the

secondary windings

21, 22, 23, and 24, the coil central openings 3 and 3', the

first cores

41 and 42, the

second cores

51 and 52, and the first resonant coil 7 and the second resonant coil 8.

The primary winding 1 is two copper wire coils, and the outer surfaces of the copper wire coils are coated with insulators.

The

secondary windings

21, 22, 23 and 24 are respectively formed by pressing double layers of copper foils, and the outer surfaces of the

secondary windings

21, 22, 23 and 24 are coated with insulators.

The primary winding 1 has a coil center opening portion 3, and the

secondary windings

21, 22, 23, and 24 have a coil center opening portion 3'.

Wherein the x, y, and z directions are orthogonal to each other and there is a first axis 6 along the z direction.

Specifically, one copper wire coil in the primary winding 1 is wound between the

secondary windings

21 and 22 along the first axis 6, the other copper wire coil is wound between the

secondary windings

23 and 24 along the first axis 6, and the

secondary windings

22 and 23 are attached together.

The two copper wire coil ends of the primary winding 1 are connected in series, the

secondary windings

21, 22, 23 and 24 respectively have 3 ends, and the ends are connected in parallel after being subjected to soldering treatment, so that a sandwich winding structure is formed.

It will be appreciated by those skilled in the art that the structures listed here are preferred and that the primary winding 1 and the

secondary windings

21, 22, 23 and 24 may have other different structures.

When the primary winding 1 is wound around the

secondary windings

21, 22, 23 and 24, the coil central opening portions 3 and 3' are overlapped.

For convenience, the primary winding 1 and the

secondary windings

21, 22, 23 and 24 are collectively referred to as a transformer winding T.

The first

magnetic cores

41 and 42 and the second

magnetic cores

51 and 52 are C-shaped magnetic cores, respectively. The first

magnetic cores

41 and 42 have outer

magnetic columns

41a, 42a, and inner

magnetic columns

41b, 42b in a U-shape, respectively.

Accordingly, the

second cores

51 and 52 also have outer

magnetic columns

51a and 52a, respectively, and inner

magnetic columns

51b and 52b in a U-shape.

Specifically, the

first cores

41 and 42 meet each other on the upper surface of the secondary winding 21 in the x direction as shown in the drawing, while the

outer legs

41a and 42a thereof meet the outside of the transformer winding T, and the

inner legs

41b and 42b meet along the coil center opening portions 3 and 3'.

The

second cores

51, 52 are connected to each other along the x-direction of the figure on the lower surface of the secondary winding 24, while the

outer legs

51a, 52a are connected to the outside of the transformer winding T and the

inner legs

51b, 52b are connected to each other along the coil center openings 3, 3'.

At this time, the

outer legs

41a and 51a are vertically contacted to the outside of the transformer winding T in the illustrated z-direction, and the

inner legs

41b and 51b are vertically contacted to the coil central openings 3 and 3' in the illustrated z-direction.

Similarly, the

outer legs

42a and 52a are vertically connected to the outside of the transformer winding T in the illustrated z-direction, and the

inner legs

42b and 52b are vertically connected to the coil central openings 3 and 3' in the illustrated z-direction.

And bonded with an adhesive at each joint, thereby forming a closed magnetic circuit.

The magnetic core can be divided into different shapes and different numbers, and only a closed magnetic circuit is formed finally.

By the above, the primary winding 1 and the

secondary windings

21, 22, 23 and 24 share the first

magnetic cores

41, 42 and the second

magnetic cores

51, 52, the magnetic core utilization rate is increased, and the volume of the LLC resonant converter can be reduced.

In addition, the first resonance coil 7 and the second resonance coil 8 are wound by litz wires, and the winding is of a single-layer structure.

The first resonance coil 7 is wound around the

first cores

41, 42 and the

second cores

51, 52 along the second axis 9 through the coil central opening portions 3 and 3'.

The second axis 9 is mutually orthogonal to the first axis 6.

The second resonance coil 8 is wound around the

first cores

41, 42 and the

second cores

51, 52 along the third axis 10 through the coil central opening portions 3 and 3'.

The third axis 10 is parallel to the second axis 9 and is orthogonal to the first axis 6.

First resonant coil 7 is wound around one side of

first cores

41 and 42 in the y direction, second resonant coil 8 is wound around the other side of

second cores

51 and 52 in the y direction, and the winding directions of first resonant coil 7 and second resonant coil 8 are opposite to each other.

Hereinafter, for convenience of description, the first resonance coil 7 and the second resonance coil 8 are collectively referred to as a resonance coil Lr.

The winding direction of the resonance coil Lr and the winding direction of the transformer winding T are thereby orthogonal to each other.

One or more resonant coils may be wound depending on the amount of inductance actually required.

From the above, referring to fig. 4 to 5, after the primary winding 1 is energized, the direction of the magnetic field generated by the transformer winding T is in the yz plane shown in the figure according to the right-hand rule. Referring to fig. 6 to 7, the direction of the magnetic field generated by the resonance coil Lr is in the xy plane of the drawing. Therefore, the directions of the magnetic fields generated by the transformer winding T and the resonant coil Lr are mutually orthogonal, and the magnetic fluxes cannot influence each other to generate loss.

According to the above embodiment, the utility model provides an among the LLC resonant converter, be integrated into sharing same magnetic core with transformer winding T and resonant coil Lr, through the coiling mode that sets up transformer winding T and resonant coil Lr for when passing through the electric current, the magnetic field direction that transformer winding T and resonant coil Lr produced each other is the quadrature, and the magnetic flux can not influence each other, increases the rate of utilization of magnetic core, can make LLC resonant converter's volume littleer. And the transformer winding T can be effectively coupled, so that the magnetomotive force on the transformer winding T is reduced, the alternating current loss of the winding is reduced, and the product efficiency is improved. Meanwhile, the copper foil as a secondary winding can enhance heat dissipation, and can avoid negative effects such as skin effect, proximity effect and the like as well as litz wire, thereby further reducing the loss of the coil, realizing the miniaturization of the product volume and greatly improving the product efficiency. In addition, the inductance in the structure can be controlled by two parameters of the size of the central opening part of the coil and the number of turns of the resonance coil Lr, so that the control and adjustment of the inductance are more flexible.

In one modification, the

secondary windings

21, 22, 23 and 24 may be formed of copper wire coils covered with insulation, and are wound in a sandwich manner with the primary winding 1. Compare embodiment 1 at this moment, copper wire coil conveniently adjusts the turn, can insert great voltage, consequently is fit for when being used for needing high-voltage output.

Further, the present invention is not limited to the above description. Changes and modifications can be made within the scope of the claims, and the scope of the present invention should be determined by the scope defined by the claims.

Description of the reference numerals

1 primary winding

21. 22, 23, 24 secondary winding

3. 3' coil central opening

41. 42 first magnetic core

51. 52 second magnetic core

41a, 42a, 51a, 52a external magnetic column

41b, 42b, 51b, 52b internal magnetic column

6 first axis

7 first resonance coil

8 second resonance coil

9 second axis

10 third axis

T-shaped transformer winding

Lr resonance coil

Claims

1. An LLC resonant converter comprising a transformer winding and a resonant coil, wherein said transformer winding comprises a primary winding and a secondary winding wound simultaneously along a first axis, and at least one of said resonant coil is wound along a second axis orthogonal to said first axis through a coil central opening of said transformer winding and an outer side of said transformer winding.

2. The LLC resonant converter according to claim 1, wherein the LLC resonant converter has a first core and a second core, and the first core and the second core are connected up and down along the coil central opening portion and the outside to form a closed magnetic circuit.

3. The LLC resonant converter of claim 2, wherein said first and second cores are respectively two C-shaped cores disposed opposite to each other, and inner legs of said C-shaped cores are vertically connected along said coil central opening portion.

4. The LLC resonant converter of any one of claims 1 to 3, wherein said resonant coils comprise a first resonant coil and a second resonant coil connected in series or parallel with each other, both said first resonant coil and said second resonant coil passing through said coil central opening portion of said transformer winding and an outer side of said transformer winding, said first resonant coil being wound along a second axis orthogonal to said first axis, said second resonant coil being wound along a third axis orthogonal to said first axis.

5. LLC resonant converter according to claim 1, characterized in that the primary winding and the secondary winding are each covered by an insulator.