WO2024074532A1

WO2024074532A1 - Coil assembly

Info

Publication number: WO2024074532A1
Application number: PCT/EP2023/077399
Authority: WO
Inventors: Martin PETZUCH; Ernst Prand-Stritzko
Original assignee: Egston System Electronics Eggenburg Gmbh
Priority date: 2022-10-04
Filing date: 2023-10-04
Publication date: 2024-04-11
Also published as: AT526570A1

Abstract

In a coil assembly (1) comprising a core (2), wherein the core (2) has a first outer leg (3), a second outer leg (4) and a middle leg (5), wherein the core (2) has a first connection plate (6) and a second connection plate (7), which are connected to the legs (3, 4, 5), wherein the coil assembly (1) has at least one opening (30), wherein the first opening (30) is surrounded by the legs (3, 4, 5) and the connection plates (6, 7) in a frame-like manner, wherein the coil assembly (1) has a first and a second coil winding (8, 9), wherein the first and the second coil winding (8, 9) are arranged around the middle leg (5), wherein the coil assembly (1) has at least one first shunt core element (10), which first shunt core element (10) is arranged, at least in regions, between the first coil winding (8) and the second core winding (9), it is proposed that the first shunt core element (10) passes through the first opening (30), at least in regions.

Description

Coil arrangement

The invention relates to a coil arrangement according to the preamble of patent claim 1.

Coil arrangements with a core are widespread in the field of electrical engineering and are used in a variety of ways, for example in transformers, chokes and much more. A coil arrangement influences the cutoff frequency or the resonance frequency of a circuit arrangement, such as a low-pass filter or a resonant circuit. However, not only these circuit arrangements have different properties and behavior at different frequencies of an incoming signal.

It has been shown that applications with relatively high switching frequencies, such as those required in small converters, lead to certain losses. These losses are largely due to the remagnetization of the core and the capacitance of the coil winding - which can no longer be ignored at correspondingly high frequencies. The power loss increases with the signal frequency. This signal frequency can have a switching frequency as its fundamental frequency.

The object of the invention is therefore to provide a coil arrangement of the type mentioned at the outset, with which the disadvantages mentioned can be avoided, which has a small size and low losses.

According to the invention, this is achieved by the features of patent claim 1.

Such a coil arrangement is finely adjustable in terms of its leakage inductance. The coil arrangement is small in size and has low power loss. The first shunt core element allows the degree of coupling to be adjusted with improved flexibility and over a wider frequency range. The degree of magnetic coupling can be specified or adjusted over a wide range.

The subclaims relate to further advantageous embodiments of the invention. Express reference is hereby made to the wording of the patent claims, whereby the patent claims are incorporated into the description at this point by reference and are deemed to be reproduced verbatim.

The invention is described in more detail with reference to the accompanying drawings, in which only preferred embodiments are shown by way of example.

Fig. 1 shows a preferred embodiment of a coil arrangement in a first axonometric view;

Fig. 2 shows the coil arrangement according to Fig. 1 in a second axonometric view;

Fig. 3 shows the coil arrangement according to Fig. 1 in elevation;

Fig. 4 Section A - A according to Fig. 5;

Fig. 5 section B - B according to Fig. 3, with the shunt core elements in a first position;

Fig. 6 shows the coil arrangement according to Fig. 1 in a third axonometric view, wherein one EQ core is removed and the coil arrangement only has one EQ core;

Fig. 7 shows the coil arrangement according to Fig. 6, with one coil winding removed and the shunt core elements shown in section;

Fig. 8 Section B - B according to Fig. 3, with the shunt core elements in a second position; and

Fig. 9 Section B - B according to Fig. 3, with the shunt core elements in the second position with fourth separating elements.

Fig. 1 to 9 each show a coil arrangement 1 or sectional views of a coil arrangement 1, which coil arrangement 1 comprises a core 2, wherein the core 2 has a first outer leg 3, a second outer leg 4 and a center leg 5, wherein the center leg 5 is arranged between the first outer leg 3 and the second outer leg 4, wherein the core 2 has a first connecting plate 6 and a second connecting plate 7, wherein the first outer leg 3, the second outer leg 4 and the middle leg 5 are each connected to the first connecting plate 6 and the second connecting plate 7, wherein the coil arrangement 1 has at least one first opening 30, wherein the first opening 30 is surrounded in a frame-like manner by the first outer leg 3, the second outer leg 4, the first connecting plate 6 and the second connecting plate 7, wherein the coil arrangement 1 has a first coil winding 8 and a second coil winding 9, wherein the first coil winding 8 and the second coil winding 9 are arranged around the middle leg 5, wherein the coil arrangement 1 has at least one first shunt core element 10, which first shunt core element 10 is arranged at least partially between the first coil winding 8 and the second coil winding 9, and wherein the first shunt core element 10 is arranged at least partially within the core 2, wherein the first shunt core element 10 extends at least partially through the first opening 30.

Such a coil arrangement 1 is finely adjustable in terms of its leakage inductance. The coil arrangement 1 has a small size and a low power loss. The first shunt core element 10 allows the degree of coupling to be adjusted with improved flexibility and over a wide frequency range. The degree of magnetic coupling can be specified or adjusted over a wide range.

The coil arrangement 1 in question is an electrotechnical device which comprises at least two coils 8, 9, therefore two wound conductors or cables and a so-called core 2. Coil arrangements 1 can be used in many areas or electrical devices. The coil arrangement 1 in question is particularly preferably designed as a transformer or as a choke.

The core 2 is circumferentially closed. The core 2, which can also be referred to as a coil core, also consists of a particularly magnetic or ferromagnetic material, which preferably comprises ferrite. The core 2 has a shape that affects the geometry of the core 2. The shape does not necessarily determine the mechanical structure. The individual parts of the core 2 described below are therefore not necessarily structurally separate from one another and are only mechanically connected to form the core 2 or as a result of the manufacture of the core 2. At least two of the components can be formed in one piece. Corresponding preferred embodiments are also discussed below.

The core 2 has a first outer leg 3, which can also be referred to as the first side leg, and a second outer leg 4, which can also be referred to as the second side leg. A center leg 5 is arranged between the first outer leg 3 and the second outer leg 4.

Furthermore, the core 2 has a first connecting plate 6 and a second connecting plate 7. The first outer leg 3, the second outer leg 4 and the middle leg 5 are each connected to the first connecting plate 6 and the second connecting plate 7.

The first outer leg 3 and the second outer leg 4 preferably have parallel side corners. The cross sections of the two outer legs 3, 4 are rectangular according to a particularly simple embodiment. According to the preferred embodiment, which is also shown in Figs. 1 to 9, the first outer leg 3 and the second outer leg 4 have a substantially plano-concave cross section, each of which has a concavely curved inner surface 29. As shown in Figs. 5 - 9, the concavely curved inner surfaces 29 of the two outer legs 3, 4 each have substantially planar end regions 28. These end regions 28 can alternatively also be convexly rounded.

The first connecting plate 6 and the second connecting plate 7 preferably have a rectangular cross-section and straight, parallel surfaces and edges. This shape essentially corresponds to a cuboid. The coil arrangement 1 has a first opening 30, which can also be referred to as a first gap or first gap-like or gap-shaped opening. The first opening 30 is surrounded in a frame-like manner by the first outer leg 3, the second outer leg 4, the first connecting plate 6 and the second connecting plate 7. The first opening 30 is arranged on a first side or side surface of the coil arrangement 1.

Preferably, and as shown in the figures, the coil arrangement 1 further comprises a second opening 31, which is also framed by the first outer leg 3, the second outer leg 4, the first connecting plate 6 and the second connecting plate 7. The second opening 31 is arranged on a second side or side surface of the coil arrangement 1. The second side of the coil arrangement 1 is opposite, preferably also parallel, to the first side of the coil arrangement 1.

It is preferably provided that the central leg 5 has a cross-section that is round at least in some areas. This preferred cross-section is therefore not a cross-section that consists only of straight lines and corners, such as a rectangular or square cross-section. Such angular cross-sections are common in known cores. Instead, the cross-section of the central leg 5 has at least one partial section that has a curve or a "non-straight line". This cross-section is for example or preferably elliptical or circular or a combination of different partial areas, with more than half of the circumference consisting of round parts in particular. The central leg 5 preferably has a - substantially - circular cross-section. The cross-section is preferably determined at a right angle to the longitudinal extension of the central leg 5. The central leg 5 therefore preferably has the shape of a cylinder.

It is preferably provided that the first connecting plate 6 and the second connecting plate 7 each protrude laterally beyond the central leg 5. The first connecting plate 6 and the second connecting plate 7 protrude beyond the central leg 5 over its entire circumference, at least at the connection of the central leg 5 with the first or second connecting plate 6, 7. The first or the second connecting plate 6, 7 preferably have the same Dimensions. Furthermore, the first outer leg 3 and the second outer leg 4 preferably also protrude beyond the middle leg 5. The two connecting plates 6, 7 preferably have the same width 22, 23 as the first outer leg 3 and the second outer leg 4. In the preferred design of the middle leg 5, it is particularly provided that a diameter 21 of the circular cross section is smaller than a first width 22 of the first outer leg 3 and/or a second width 23 of the second outer leg 4. The width is to be determined perpendicular to the longitudinal extension.

The coil arrangement 1 has a first coil winding 8 and a second coil winding 9. The first coil winding 8 and the second coil winding 9 are arranged or wound one behind the other or next to each other around the center leg 5. The first coil winding 8 does not include the second coil winding 9 and/or the second coil winding 9 does not include the first coil winding 8. When the coil arrangement 1 is designed as a transformer, the two coil windings 8, 9 each form their own electrical circuit and are each connected to separate connection areas of the coil arrangement 1. When the coil arrangement 1 is designed as a choke, the two coil windings 8, 9 are connected to one another in series in terms of circuitry.

As already explained, the geometric shape of the core 2 is formed by five individual elements. This structure essentially corresponds to a closed E-core in its base. The five geometric individual elements or molded parts can each be designed as individual parts which are mechanically connected to one another. The core is preferably composed of two parts, whereby the two parts are preferably designed essentially the same. The core 2 is preferably formed from a first EQ core 12 and a second EQ core 13. The term EQ core is a technically widespread or usual term for the two primary parts of the core 2, as shown in Figs. 1 - 9.

In this construction, the first and second EQ cores 12, 13 each form a section of the complete core 2. Each of the three legs, i.e. the first outer leg 3, the second outer leg 4 and the middle leg 5, is separated or interrupted in the middle. Only through assembly or the By assembling the two EQ cores 12, 13, the first outer leg 3, the second outer leg 4 and the middle leg 5 are formed.

With the above-mentioned composition of the two EQ cores 12, 13, it is preferably provided that the first EQ core 12 contacts the second EQ core 13 at least twice directly physically or without interruption or without an air gap. This takes place with the first outer leg 3 and the second outer leg 4. Furthermore, it can be provided that such direct contact or mechanical support also exists with the center leg 5. However, it is particularly preferably provided that the center leg 5 has an air gap 14, which air gap 14 is arranged between the first coil winding 8 and the second coil winding 9. The center leg 5 has a first center leg part and a second center leg part, wherein the first center leg part is connected to the first connecting plate 6 and the second center leg part is connected to the second connecting plate 7. Both central leg parts are each shorter than the parts of the first and second outer legs 3, 4 arranged parallel to them. In the assembled state, the parts of the first and second outer legs 3, 4 are connected to one another directly and without interruption. Since the two central leg parts are each shorter than the parts of the first and second outer legs 3, 4, the central leg parts are not connected to one another and form a so-called air gap. Air gap is the technical term for such an interruption of a magnetic circuit. An air gap 14 formed in this way is shown in Fig. 4.

Preferably - and as shown in the figures - it is provided that the coil arrangement 1 has an electrically insulating first separating element 15. This first separating element 15 is arranged between the center leg 5 and the first coil winding 8 and/or the second coil winding 9. The first separating element 15 therefore encloses the center leg 5. Particularly preferably, this first separating element 15 also forms a lateral boundary for the two coil windings 8, 9. The coil arrangement 1 has at least a first shunt core element 10. Preferably, and as shown in Figs. 1 to 9, the coil arrangement 1 also has a second shunt core element 11.

The first shunt core element 10 and the preferred second shunt core element 11 are not physically connected to the core 2 in an electrically conductive connection. The first shunt core element 10 and the preferred second shunt core element 11 are made of a magnetic material, which can also be referred to as a magnet material. The magnetic material is in particular a magnetic metal or a magnetic metal alloy. In particular, the first shunt core element 10 and the preferably provided second shunt core element 11 are made of a ferromagnetic material, in particular comprising ferrite. The first shunt core element 10 and the preferably provided second shunt core element 11 are not made of an insulator or an electrically insulating material, in particular not of a plastic.

The first shunt core element 10 is arranged at least in some areas close to the first coil winding 8 and the second coil winding 9. The preferred second shunt core element 11 is arranged at least in some areas close to the first coil winding 8 and the second coil winding 9. The close arrangement means that there is no electrical contact between the parts and that they are not directly or immediately connected to the coil windings 8, 9. There is therefore an air gap between the first shunt core element 10 and the core 2. The same also applies to the preferably provided second shunt core element 11. The first and second shunt core elements 10, 11 can also be referred to as a magnetic shunt or bypass. The first shunt core element 10 and the preferred second shunt core element 11 serve to control or specifically influence the leakage inductance of the coil arrangement 1.

The first shunt core element 10 is arranged at least in regions within the core 2. In particular, it is provided that the preferably provided second shunt core element 11 is also arranged at least in regions is arranged within the core 2. The core 2 therefore has a corresponding receiving area.

It is provided that the first shunt core element 10 extends through the first opening 30 at least in some areas. The first shunt core element 10 is therefore arranged at least partially or in some areas in the first opening 30. It is preferably provided that a part of the first shunt core element 10 protrudes from the core 2 through the first opening. The first shunt core element 10 is therefore not arranged between the central leg 5 and the first outer leg 3 or the second outer leg 4, but is arranged in the first opening 30, which can also be referred to as an access opening, which first opening 30 is bordered by both the first and the second outer legs 3, 4. This positioning enables significantly better adjustability than a position between the central leg 5 and the first outer leg 3. Furthermore, the first shunt core element 10 can be replaced without it being necessary to open the core 2 and then reassemble it.

In particular, the preferably provided second shunt core element 11 extends at least partially through the second opening 31. With regard to corresponding details, reference is made to the previous paragraph concerning the shunt core element 10 and the first opening 30.

The following describes features of the first shunt core element 10 and its arrangement in the coil arrangement 1. This also includes the preferred embodiments relating to the preferably provided second shunt core element 11, even if this is not explicitly mentioned.

In the receiving area in which the first shunt core element 10 is arranged within the core 2, the inner surfaces of the first outer leg 3 and the second outer leg 4 are located in the inner area of the core 2. These two inner surfaces can be flat. As already explained above, the first outer leg 3 and the second outer leg 4 each have a concavely curved inner surface 29. Particularly preferably, the concavely curved inner surfaces 29 each have two flat end regions 28. Furthermore, the center leg 5 is located in the region between the two coil windings 8, 9 in the interior of the core 2. The center leg 5 preferably has a cross-section that is at least partially round or a surface that is at least partially convex. The first shunt core element 10 can essentially have any shape that allows an arrangement in this region within the core 2.

According to a preferred embodiment, it is provided that the first shunt core element 10 has a concavely curved first surface 16. The first surface 16 is preferably concavely curved over its entire circumference. However, it can also be provided that the concavely curved first surface 16 has at least one single straight section. Furthermore, the concavely curved first surface 16 can also be partially reproduced from a composition of a larger number of straight surfaces, but without actually comprising round sections. This concavely curved first surface 16 represents an inner side or inner surface of the first shunt core element 10. The first shunt core element 10 is arranged opposite the center leg 5. The first surface 16 faces the center leg 5. As a result, the first shunt core element 10 encloses certain areas of the circumference of the center leg 5. This results in a very good coupling between the first shunt core element 10 and the core 2.

The first shunt core element 10 particularly preferably has a plano-concave base surface 17. The term "plano-concave" is known from optics and includes a surface which has a first side surface 18 and a second side surface 19. The inner corner points of these two side surfaces 18, 19 are connected to the concave curved first surface 16. The outer corner points of the two side surfaces 18, 19 are preferably connected to a straight second surface 24. This preferred embodiment is shown in particular in Figs. 5, 7, 8 and 9. Another name for this shape is uniaxial concave curved base surface. As already explained, the first shunt core element 10 has a first side surface 18 and a second side surface 19, the first side surface 18 being arranged opposite the first outer leg 3 and the second side surface 19 being arranged opposite the second outer leg 4. According to the preferred embodiment, an electrically insulating second separating element 20 is arranged between the first side surface 18 and the first outer leg 3 and between the second side surface 19 and the second outer leg 4. The second separating element 20 preferably encloses the first shunt core element 10 in all areas which are arranged within the core 2. There is a possibility that the first shunt core element 10 may become oversaturated. Tests have shown that the distance between the first shunt core element 10 and the first and second outer legs 3, 4 has an influence on this. This distance can be specifically set and ensured by the second separating element 20.

This second separating element 20 can be designed separately from the first separating element 15. It is preferably provided that the first separating element 15 and the second separating element 20 are connected to one another and/or are designed as one piece. The first shunt core element 10 and the preferred second shunt core element 11 are designed to be physically independent of the electrically insulating first separating element 15 and/or the second separating element 20. The shunt core elements 10, 11 do touch the preferred separating elements 15, 20 but are made of different materials.

In the preferred presence of the second shunt core element 11, it is provided in particular that the second shunt core element 11 is at least partially enclosed by a third separating element 25, wherein with regard to the preferred embodiments, reference is made to the above discussions on the second separating element 20.

As explained above, the distance between the first shunt core element 10 and the first and second outer legs 3, 4 influences the saturation of the first shunt core element 10 and can prevent oversaturation if appropriately dimensioned. It has been shown that furthermore A thickness 26 of the first shunt core element 10 also influences the saturation of the first shunt core element 10. Preferably, this thickness 26 is selected accordingly.

The first shunt core element 10 can be fixed or immovably attached in or to the core 2. However, it is preferably provided that the first shunt core element 10 is mounted so as to be longitudinally displaceable along the first side surface 18 and the second side surface 19. This allows the distance between the first surface 16 of the first shunt core element 10 and the center leg 5 to be adjusted. Furthermore, this changes the length or section of the first shunt core element 10 which is arranged within the core 2. This enables very precise fine adjustment of the leakage inductance.

To ensure a predeterminable minimum distance between the first shunt core element 10 and the center leg 5, a fourth separating element 27 is preferably provided, which is arranged only in the area between the center leg 5 and the first surface 16 of the first shunt core element 10. Such an embodiment is shown in Fig. 9. In the preferred presence of a second shunt core element 11, a fourth separating element 27 is also provided between the second shunt core element 11 and the center leg 5.

After adjusting the position of the first shunt core element 10, the first shunt core element 10 can be firmly locked in the relevant position, for example by gluing, clamping, riveting and/or screwing. The coil arrangement 1 preferably has a locking arrangement for blocking or locking a position of the first shunt core element 10. The locking arrangement in question comprises in particular a merely temporary lock, which enables targeted opening and locking. This enables adjustment for different application purposes. Furthermore, this can compensate for long-term changes in the core or the coil arrangement. The following are principles for understanding and interpreting the present disclosure.

Characteristics are usually introduced with an indefinite article “ein, eine, eines, einer”. Unless the context indicates otherwise, “ein, eine, eines, einer” is therefore not to be understood as a number.

The conjunction "or" is to be interpreted as inclusive and not exclusive. Unless the context indicates otherwise, "A or B" also includes "A and B", where "A" and "B" represent any characteristics.

By means of an ordering number, for example "first", "second" or "third", a feature X or an object Y in several embodiments are distinguished, unless this is defined otherwise by the disclosure of the invention. In particular, a feature X or object Y with an ordering number in a claim does not mean that an embodiment of the invention covered by this claim must have a further feature X or a further object Y.

Claims

PATENT CLAIMS

1. Coil arrangement (1) comprising a core (2), wherein the core (2) has a first outer leg (3), a second outer leg (4) and a central leg (5), wherein the central leg (5) is arranged between the first outer leg (3) and the second outer leg (4), wherein the core (2) has a first connecting plate (6) and a second connecting plate (7), wherein the first outer leg (3), the second outer leg (4) and the central leg (5) are each connected to the first connecting plate (6) and the second connecting plate (7), wherein the coil arrangement (1) has at least one first opening (30), wherein the first opening (30) is surrounded in a frame-like manner by the first outer leg (3), the second outer leg (4), the first connecting plate (6) and the second connecting plate (7), wherein the coil arrangement (1) has a first coil winding (8) and a second coil winding (9), wherein the first coil winding (8) and the second coil winding (9) are arranged around the central leg (5), wherein the coil arrangement (1) has at least one first shunt core element (10), which first shunt core element (10) is arranged at least partially between the first coil winding (8) and the second coil winding (9), and wherein the first shunt core element (10) is arranged at least partially within the core (2), characterized in that the first shunt core element (10) at least partially passes through the first opening (30).

2. Coil arrangement (1) according to claim 1, characterized in that the central leg (5) has a cross-section that is round, at least in regions.

3. Coil arrangement (1 ) according to claim 2, characterized in that the central leg (5) has a circular cross-section, and that a diameter (21 ) of the circular cross-section is smaller than a first width (22) of the first outer leg (3) and a second width (23) of the second outer thigh (4).

4. Coil arrangement (1) according to claim 1, 2 or 3, characterized in that the core (2) is formed from a first EQ core (12) and a second EQ core (13).

5. Coil arrangement (1) according to one of claims 1 to 4, characterized in that the central leg (5) has an air gap (14), and that the air gap (14) is arranged between the first coil winding (8) and the second coil winding (9).

6. Coil arrangement (1) according to one of claims 1 to 5, characterized in that the coil arrangement (1) has an electrically insulating first separating element (15), and that the first separating element (15) is arranged between the center leg (5) and the first coil winding (8) and/or the second coil winding (9).

7. Coil arrangement (1) according to one of claims 1 to 6, characterized in that the first shunt core element (10) has a concavely curved first surface (16), and that the first surface (16) faces the center leg (5).

8. Coil arrangement (1) according to claim 7, characterized in that the first shunt core element (10) has a plano-concave base surface (17).

9. Coil arrangement (1) according to one of claims 1 to 8, characterized in that the first shunt core element (10) has a first side surface (18) and a second side surface (19), the first side surface (18) being arranged opposite the first outer leg (3) and the second side surface (19) being arranged opposite the second outer leg (4), and that an electrically insulating second separating element (20) is arranged between the first side surface (18) and the first outer leg (3) and between the second side surface (19) and the second outer leg (4).

10. Coil arrangement (1) according to claim 9, characterized in that the first separating element (15) and the second separating element (20) are connected to one another.

11. Coil arrangement (1) according to claim 9 or 10, characterized in that the first shunt core element (10) is mounted so as to be longitudinally displaceable along the first side surface (18) and the second side surface (19).

12. Coil arrangement (1) according to one of claims 1 to 11, characterized in that the coil arrangement (1) has a locking arrangement for blocking a position of the first shunt core element (10).

13. Coil arrangement (1) according to one of claims 1 to 12, characterized in that the coil arrangement (1) has a second opening (31), the second opening (31) being surrounded in a frame-like manner by the first outer leg (3), the second outer leg (4), the first connecting plate (6) and the second connecting plate (7), that the coil arrangement (1) has a second shunt core element (11), that the second shunt core element (11) is arranged at least in regions between the first coil winding (8) and the second coil winding (9), and that the second shunt core element (11) extends at least in regions through the second opening (31).

14. Coil arrangement (1) according to one of claims 1 to 13, characterized in that the first shunt core element (10) consists of a magnetic, in particular ferromagnetic, material, which material preferably comprises ferrite.

15. Coil arrangement (1) according to one of claims 6 to 14, characterized in that the first shunt core element (10) is formed independently of the electrically insulating first separating element (15).

16. Transformer with a coil arrangement (1) according to one of claims 1 to 15.

17. Choke with a coil arrangement (1) according to one of claims 1 to 15.