EP3729477A1

EP3729477A1 - Transformer core and transformer

Info

Publication number: EP3729477A1
Application number: EP18808326.5A
Authority: EP
Inventors: Christian Winter; Jan Riedel
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2017-12-20
Filing date: 2018-11-23
Publication date: 2020-10-28
Also published as: CN111466002A; US11605500B2; JP7087083B2; KR102623872B1; US20210065969A1; JP2021507534A; CN111466002B; KR20200100127A; WO2019120882A1; DE102017223322A1

Abstract

The invention relates to a transformer core with at least one additional leg. Said additional leg is used to form a leakage path. In order to optimize the installation space and for easier connection of the transformer windings, the transformer legs and the additional leakage path legs are not arranged along a common line.

Description

description

title

Transformer core and transformer

The present invention relates to a transformer core and a

Transformer with such a transformer core.

State of the art

Power electronic DC-DC converters can use transformers if an adaptation of the input to the output voltage or a galvanic isolation is necessary. Depending on the topology chosen, a high series inductance in series with the transformer may be desirable. This longitudinal inductance can be realized, for example, as external inductance, or can also be integrated into the transformer as leakage inductance. To limit magnification of the transformer by integrating the stray inductance, additional stray flux may be conducted in a high magnetic permeability material in the transformer.

The document EP 0 355 298 A2 discloses a switching power supply with a

Transformer with an air gap. In particular, by inserting ferrite plates into the air gap, the air gap can be divided into a plurality of partial air gaps, so that the spatial extent of the stray magnetic field is reduced.

Disclosure of the invention

The present invention discloses a transformer core with the features of patent claim 1, as well as a transformer with the features of claim 10. Accordingly, it is provided:

A transformer core with a first transformer leg, a second transformer leg and a Streupfadenschenkel. The first

Transformer leg has a first longitudinal axis. The second

Transformer leg has a second longitudinal axis. The

Litter path has a further longitudinal axis. Furthermore, a first plane is predetermined which extends through the first longitudinal axis and the second longitudinal axis. In this case, the Streupfadschenkel is arranged such that the

Longitudinal axis of the Streupfadschenkels is outside the first plane, which is spanned by the first longitudinal axis and the second longitudinal axis.

Furthermore, it is provided:

A transformer having a transformer core according to the invention and a first winding, which is arranged on the first transformer arm and a second winding, which is arranged on the second transformer arm.

Advantages of the invention

The present invention is based on the finding that the longitudinal or leakage inductance of the transformer can be increased by the use of additional Streupfadschenkel in a transformer core. Such an increase in the longitudinal or leakage inductance of the transformer may be desirable depending on the circuit topology in which such a transformer is to be used. However, the additional lead

Streupfadschenkel the transformer core to an enlargement of the

Installation space. In particular, the additional Streupfadschenkel complicate the connection of the primary and secondary windings on such

Transformer.

The present invention is therefore based on the idea to take into account this knowledge and to provide an efficient geometry for a transformer core with additional Streupfadschenkeln, which further a possible efficient installation of such a transformer core allows. Moreover, it is an object of the present invention to provide a geometry for a

To provide transformer core with additional Streupfadschenkeln that allows the most convenient connection of the primary and secondary winding of the transformer.

To this end, the present invention provides that the legs of the transformer, which receive the primary and secondary windings, as well as the additional Streupfadschenkel not to arrange in a linear structure. Rather, the additional Streupfadschenkel are arranged away from a line, which is formed by the transformer legs for the primary and secondary windings. By such a "shifting" of the Streupfadschenkel in relation to the

Transformator leg can be created a transformer core geometry, which on the one hand the most efficient installation of such

Transformers allows, and also makes the connection of the primary and secondary windings of the transformer as well as possible, without these connections are blocked or impaired by a Streupfadenschenkel.

The term "transformer legs" is that part of the

Transformer core to understand which is surrounded by a winding, for example, the primary winding or the secondary winding of the transformer. In general, the individual transformer legs, in particular the legs of the primary winding and the secondary winding extend at least approximately parallel to one another. The Streupfadschenkel is another part of the transformer core, which also usually runs at least approximately parallel to the transformer legs. However, in contrast to the transformer legs, no winding is usually arranged on this scattering filament limb. Rather, the Streupfadschenkel primarily serves to increase the leakage inductance of the transformer.

The legs of the transformer core, that is, the transformer legs and litter path legs can each be connected to each other via suitable transformer yokes. For this purpose, in principle any suitable geometries are possible, as will be explained in more detail below. In particular, a plurality of transformer legs and optionally Streupfadschenkel and at least a portion of the transformer yokes may be formed together from a material or composite material. Alternatively, it is also possible to carry out the individual transformer legs, the scattering filament legs and yokes in each case as individual components and to connect them to each other by means of suitable further fastening possibilities or to fix them to one another.

The inventive structure of the transformer core thus a better, space-optimized integration of the transformer is achieved in circuits. The connection points of the transformer, in particular, the

Connection points of the primary and secondary windings are easily accessible, so that no long connection paths and associated unused areas are required. This reduces the required space and beyond the occurring electrical resistance.

According to an embodiment, the transformer core comprises a first transformer yoke and a second transformer yoke. The first

Transformator leg, the second transformer leg and the

Streupfadschenkel are hereby arranged between the first transformer yoke and the second transformer yoke. This creates a self-contained transformer core structure. The term "closed" in this case, however, expressly includes any required air gaps for adjusting the inductances in the transformer. As already described above, the transformer legs mean those parts of the transformer to which the windings, in particular the primary and secondary windings, are arranged. The Streupfschenschenkel corresponds to another component, in the same way as the

Transformer leg is arranged, but without an additional turn is disposed on the Streupfschenschenkel. The individual legs of the transformer core, that is, the transformer legs and the

Streupfadschenkel are connected to each other via the first and second transformer yoke. In particular, the legs can each have end faces, wherein the two yokes are respectively arranged on the end faces of the legs. The connections and fixations of the transformer legs, Streupfadschenkel and yokes can by means of any suitable

Devices, brackets, etc. take place. According to one embodiment, the first transformer yoke, the first transformer leg, the second transformer leg and the

Streupfadschenkel formed coherently. Depending on the configuration, however, it is also possible to use any combination of the required

Components of the transformer core in each case coherently form. For example, the Streupfadschenkel with a yoke

be formed contiguous, while the first and the second

Transformer leg with the other yoke are formed contiguous.

According to one embodiment, an air gap is arranged at least between the first and the second transformer yoke and the scattering filament leg. In this way, the leakage inductance in the magnetic path through the yoke and the streamer leg can be increased. Optionally, a suitable filling material can be introduced in the air gap, which fills the air gap completely or partially.

According to one embodiment, the scattering filament leg comprises ferromagnetic powder grains. By using ferromagnetic powder grains, the inductance can also be increased. Such configurations with ferromagnetic powder grains are also known by the term distributed air gaps.

According to one embodiment, a second plane can be defined by the longitudinal axes of the second transformer leg and the scattering leg. In particular, the Streupfadschenkel can be arranged such that the second plane is perpendicular to the first plane, which is spanned by the longitudinal axes of the first and second transformer arm.

According to one embodiment, the transformer core comprises several

Streupfadschenkel, each Streupfschenschenkel each having an individual longitudinal axis. In particular, the plurality of litter path legs can be arranged such that all longitudinal axes of the Streupfadschenkel are located outside the first plane, which through the first longitudinal axis and the second longitudinal axis of the first transformer leg and the second transformer leg are formed. In this way, the required leakage inductance can be formed by several litter path legs. As a result, the individual Streupfadschenkel can be made particularly small and efficient, so that, if necessary, the required space can further reduce.

According to one embodiment, a plane parallel to the first plane spanned by the first and second longitudinal axes of the first transformer leg and the second transformer leg can be spanned by the longitudinal axes of at least two scattering string legs. In this way, the first transformer leg and the second transformer leg can be arranged in a line which runs parallel to a line which is formed by two Streupfadschenkel. This allows a particularly compact and efficient construction of the

Transformer core with Streupfadenschenkeln.

According to an embodiment, at least two scattering filament legs may be arranged such that the longitudinal axes of the two scattering filament legs define a plane that is perpendicular to the first plane defined by the first longitudinal axis of the first transformer leg and the second longitudinal axis of the second transformer leg. These

Configuration allows arrangement of the Streupfadschenkel on both sides of a line, which is formed by the first transformer leg and the second transformer leg.

The above embodiments and developments can, as far as appropriate, combine arbitrarily. Further refinements, further developments and implementations of the invention also include combinations of previously or below that are not explicitly mentioned with respect to FIG

Embodiments described features of the invention. In particular, the person skilled in the art will also consider individual aspects as improvements or

Add supplements to the respective basic forms of the invention.

Brief description of the drawings Further features and advantages of the present invention will be explained below with reference to the figures. Show it:

1 is a perspective view of a transformer core according to an embodiment; and

Figs. 2 to 6: schematic representations of cross sections through

Transformer cores according to embodiments of the present invention.

Description of embodiments

FIG. 1 shows a schematic representation of a perspective view of a transformer core 1 according to an embodiment. The transformer core comprises a first transformer leg 10, a second

Transformer leg 20, a Streupfschenschenkel 30, and a first yoke 41 and a second yoke 42. As can be seen, are the first

Transformer leg 10, the second transformer arm 20 and the Streupfadschenkel 30 between the first Transformatorjoch 41 and the second Transformatorjoch 42 arranged. In particular, the upper end faces of the first transformer leg 10, the second

Transformer leg 20 and the Streupfadschenkels 30 toward the upper, second Transformatorjochs 42. The lower end faces of the first transformer leg 10, the second transformer arm 20 and the Streupfadschenkels 30 point in the direction of the lower, first

Transformer yoke 41.

The first transformer leg 10 in this case has a longitudinal axis 11. By way of example, this longitudinal axis 11 may be an axis of symmetry extending from the upper end face to the lower end face of the first transformer leg 10. In principle, however, any other longitudinal axes, in particular longitudinal axes between the upper and the lower end face of the first transformer leg 10 are possible. Analogously, the second transformer leg 20 has a second longitudinal axis 21 which extends between the upper and the lower end face of the second transformer leg 20. Likewise, the Streupfadschenkel 30 has a further longitudinal axis 31st on, which extends between the upper and the lower end face of the Streupfadschenkels 30.

In the embodiment shown here according to FIG. 1, the first transformer leg 10 and the second transformer leg 20 as well as the scattering filament legs 30 each have an at least approximately square cross-section perpendicular to the respective longitudinal axes. However, the present invention is not limited to such square cross sections. Rather, any shapes for the cross sections of the transformer legs 10, 20 and the Streupfadschenkel 30 are possible. For example, rectangular, circular, oval or other types of cross sections are possible.

The longitudinal axis 11 of the first transformer leg 10, the second

Longitudinal axis 21 of the second transformer leg 20 and the further longitudinal axis 31 of the Streupfadschenkels 30 are not in a common alignment. In other words, the first longitudinal axis 11 of the first transformer leg 10 and the second longitudinal axis 21 of the second

Transformator leg 22 lie in a virtual plane, and the longitudinal axis 31 of the Streupfadschenkels 30 lies outside this virtual plane, which by the longitudinal axes 11, 21 of the first and second

Transformer legs 10, 20 is clamped. In this way, by the structure of the transformer core 1 an angled structure, here

For example, formed an L-shaped structure.

To form a transformer with the illustrated here

Transformer core structure 1, for example, on the first

Transformer leg 10 a first winding 61, for example a

Primary winding can be arranged, and at the second transformer leg 20, a second winding 62, for example, a secondary winding. In this way, an inductive energy transfer between the winding on the first transformer leg 10 and the winding on the second

Transformer leg 20 possible. To customize and adjust the

Stray inductance of the transformer with the structure of the transformer core 1 shown here, a gap, for example an air gap 50, can be provided in particular on the scattering filament leg 30. For example, this air gap 50 between the Streupfschenschenkel 30 and the upper, second transformer yoke 42 are located. In addition, in principle, however, any other positions for the air gap 50 in the region of the Streupfadschenkels 30 are possible. In particular, by variation and

Adjusting the dimensions of the air gap 50, the leakage inductance of the

Transformers adapted and varied.

Figure 2 shows a schematic representation of a cross section through a transformer with a transformer core 1 according to one embodiment.

The first and second transformer yokes 41, 42 of FIG. 1 are shown in dashed lines. By the first longitudinal axis 11 of the first

Transformator leg 10 and the second longitudinal axis 21 of the second

Transformer leg 20 is defined a plane which is shown in the cross section of Figure 2 by A-A '. The longitudinal axis 31 of the

Streupfadschenkels 30 is located away from this plane A-A '.

For example, by the second longitudinal axis 21 of the second

Transformer leg 20 and the longitudinal axis 31 of the Streupfadschenkels 30 another plane are spanned, which is shown in the cross section of Figure 2 by B-B '. In particular, the planes according to A-A 'and the plane according to B-B' can intersect at right angles or at least approximately at right angles.

For example, a first winding, in particular a primary winding of a transformer, may be provided on the first transformer leg 10, and a further winding, in particular a secondary winding of a transformer, may be provided on the second transformer leg 20, for example. Due to the angled geometry of the structure for the transformer core 1 while the terminals of the primary winding and the secondary winding are particularly accessible.

FIG. 3 shows a schematic representation of a cross section through a transformer core 1 according to a further embodiment. These

Embodiment differs from the previously described

Embodiment according to Figure 2 in that the transformer core 1 in this case has two Streupfadschenkel 30. Both Streupfadschenkel 30 each have a longitudinal axis 31 which lies outside the plane AA ', by the first longitudinal axis 11 of the first transformer leg 10 and the second Longitudinal axis 21 of the second transformer arm 20 is clamped. In the embodiment shown here, the two longitudinal axes 31 of the Streupfadschenkel 30 and the longitudinal axis 21 of the second

Transformer leg 20 in a common plane B-B '. However, this is only to be understood as an exemplary embodiment. In addition, the transformer core 1 may also have any other configuration in which the longitudinal axes 31 of the Streupfadschenkel 30 outside the plane A-A ', which are spanned by the first longitudinal axis 11 of the first transformer leg 10 and the second longitudinal axis 21 of the second transformer leg 20.

Figure 4 shows a schematic representation of another embodiment of a transformer core 1. In this embodiment, the

Transformer core 1 four litter path legs 30, each having a longitudinal axis 31. The four Streupfaschenkel 31 are, for example along a

Rectangles or squares are arranged on the outer corners of the structure formed by the transformer core 1.

FIG. 5 shows a schematic representation of a further embodiment for a transformer core 1. In this case, the transformer core 1 has an elongate scattering thread limb 30 which extends parallel to the first longitudinal axis 11 of the first transformer leg 10 and the second

Longitudinal axis 21 of the second transformer leg 20 spanned plane A-A 'over the dimensions between the first transformer leg 10 and the second transformer leg 20 extends. For example, on each side of the plane A-A 'a corresponding Streupfadschenkel 30 may be provided. In addition, however, it is also possible to provide only one Streupfschenschenkel 30 on one side, which extends over the entire length between the first transformer arm 30 and the second transformer arm 20.

Finally, FIG. 6 shows a further embodiment of a transformer core 1 with a littering path 30. As shown here, the

Transformer core 1 does not necessarily have a square, rectangular or L-shaped structure with a right angle. It is for the

transformer core 1 according to the invention basically possible to provide at least one Streupfadenschenkel 30, the longitudinal axis 31 away from the Surface is located, which is spanned by the longitudinal axes 11, 21 of the two transformer legs 10, 20.

As material for the transformer legs 10, 20, the transformer yokes 41, 42 and the or the Streupfadschenkel 30 any materials are possible, which are basically suitable for the production of transformer cores.

In particular, the individual legs and yokes can also be realized from sheets or laminated cores. In this case, also several of the components of transformer legs 10, 20, Streupfadschenkel 30 and

Transformer yokes 41, 42 form a common component. For example, with the exception of the first, upper transformer yoke 42, all

Components are executed as a common component. In addition, it is also possible, for example, the or the litter path yoke 30 and the first transformer yoke 41 to perform as a common component and the first and second transformer legs 10, 20 and the second

Transformer yoke 42 also run as a common component.

Of course, any other combinations of components of the previously described transformer core 1 are moreover than

common component possible.

As already described above, a gap 50, in particular an air gap, may be provided between the scattering-filament leg 30 and the first transformer yoke 41 and / or the second transformer yoke 42. If appropriate, any suitable filling materials can also be embedded in this air gap.

Furthermore, it is also possible that or the Streupfadschenkel 30 than

To carry out litter path with distributed air gap, that is the

To carry out lattice path of a material with ferromagnetic powder grains.

In summary, the present invention relates to a transformer core having at least one additional leg. This additional leg serves to form a scattering path. To optimize the space and for easier connection of the transformer windings are the Transformer legs and the additional Streupfadenschenkel not arranged along a common line.

Claims

claims

A transformer core (1) comprising: a first transformer leg (10) having a first longitudinal axis (11); a second transformer leg (20) having a second longitudinal axis (21); and a streamer blade (30) having a further longitudinal axis (31), wherein the longitudinal axis (31) of the Streupfadschenkels (30) is outside a first plane (AA '), that of the first longitudinal axis (11) and the second longitudinal axis (21) is clamped.

2. transformer core (1) according to claim 1, comprising: a first transformer yoke (41); and a second transformer yoke (42), wherein the first transformer leg (10), the second transformer leg (20) and the straightening filament legs (30) are disposed between the first transformer yoke (41) and the second transformer yoke (42).

3. transformer core (1) according to claim 2, wherein the first

Transformer yoke (41), the first transformer arm (10), the second transformer arm (20) and the Streupfadschenkel (30) are formed contiguous.

4. transformer core (1) according to claim 2 or 3, wherein between the second transformer yoke (42) and the Streupfadschenkel (30), an air gap (50) is arranged.

5. transformer core (1) according to one of claims 1 to 4, wherein the Streupfadschenkel (30) comprises ferromagnetic powder grains.

6. transformer core (1) according to one of claims 1 to 5, wherein a second plane, of the second transformer leg (20) and the

Streupfadschenkel (30) is stretched, perpendicular to the first plane (A- A '), which is spanned by the first and the second longitudinal axis (11, 21).

7. transformer core (1) according to one of claims 1 to 6, with a plurality of Streupfadschenkeln (30), each having a longitudinal axis (31), wherein the longitudinal axes (31) of the Streupfadschenkel (30) outside the first plane (AA ') located, which is spanned by the first longitudinal axis (11) and the second longitudinal axis (21).

8. transformer core (1) according to claim 7, wherein the longitudinal axes (31) of at least two Streupfadschenkeln (30) to relax a plane which is parallel to the first plane (AA ') extending from the first and the second longitudinal axis (11, 21) is clamped.

9. transformer core (1) according to claim 7 or 8, wherein the longitudinal axes (31) of at least two Streupfadschenken (30) has a plane (B-B ')

span perpendicular to the first plane (A-A '), which is spanned by the first and the second longitudinal axis (11, 21).

10. A transformer, comprising: a transformer core (1) according to any one of claims 1 to 9; a first winding (61) disposed on the first transformer leg (10); and a second winding (62) disposed on the second transformer leg (20).