Coil arrangement for an inductive power transfer system

Abstract

Coil arrangement for an inductive power transfer system, wherein the coil arrangement comprises a winding and a stack, wherein the winding axis is aligned parallel to the stack direction, where the winding is a ring winding, the stack has layers of magnetizable material, wherein an amorphous iron alloy with a nanocrystalline structure is used as the magnetizable material, where the relative magnetic permeability of the material exceeds a value of 30,000, wherein a film made of polyethylene, polypropylene or polyimide is arranged between each layer, wherein the stack has adhesive layers, so that the respective film is bonded to the layers on both sides, wherein the magnetic field generated by the winding or penetrating the winding is at least partially guided by a coil core arrangement which has the stack as a yoke and a ferrite core inserted in the middle of the winding and has ferrite material on the outside, wherein the ferrite core and the further ferrite material each form a leg, wherein the ferrite core and the other ferrite material touch the stack and / or are bonded to it with adhesive or potted with potting compound, the stack is arranged with adhesive bonding on a steel support plate.

Description

[0001] The invention relates to a coil arrangement for a system for inductive energy transfer.

[0002] It is generally known to wind a coil winding around a coil core. Ferrite is used as the material for the coil core.

[0003] From US 2010 / 0 007 215 A1, a soft magnetic module for contactless power transmission is known as the closest prior art.

[0004] Inductive power transfer is known from US 2011 / 0 210 696 A1.

[0005] An electrical coupling device is known from WO 98 / 31 073 A2.

[0006] Layers of highly permeable coil core material are known from the publication ARAI, KI: High frequency magnetic permeability of Sendust ribbons made by a disk quenching method. In: IEEE Transaction on Magnetics, Vol. MAG-21, 1985, No. 5, pp. 1924-1926. ISSN 0018-9464.

[0007] A device for contactless energy transmission is known from DE 10 2010 050 935 A1.

[0008] Inductive power transmission is known from WO 2011 / 112 795 A1.

[0009] The invention is therefore based on the objective of further developing a coil arrangement for an inductive energy transfer system, whereby improved efficiency in manufacturing and operation should be achievable.

[0010] According to the invention, the problem is solved by the features specified in claim 1.

[0011] Important features of the invention in the coil arrangement are that it is intended for an inductive energy transfer system, wherein the coil arrangement comprises a winding and a stack, wherein the winding axis is aligned parallel to the stack direction, in particular wherein the winding is a flat winding and / or concentric winding, in particular a ring winding.

[0012] An advantage of this approach is the low specific gravity of the stack. This allows for the reduction or even elimination of the need for heavy ferrite materials. Furthermore, a stack is more elastic and flexible than a solid, single-piece material. The layered structure also enables a high degree of magnetization, as the interaction between the flat layers is reduced due to their spacing. The quasi-planar arrangement of the Weiss domains is particularly beneficial, since in a three-dimensional arrangement, magnetic field lines would radiate around some of the domains until complete saturation is reached.

[0013] Advantageously, the coil arrangement according to the invention is applicable to a system for inductive energy transfer.

[0014] An advantage of the invention is therefore also that improved manufacturing efficiency can be achieved by replacing costly ferrite parts with the foil stack according to the invention. Furthermore, the stack is generally less brittle than the ferrite material and can even be applied to and / or operated on surfaces prone to vibration.

[0015] Furthermore, manufacturing is simplified because simple bonding processes are sufficient to create the connections. Bonding to a substrate is possible to achieve higher stiffness.

[0016] In a preferred embodiment, the winding is implemented using conductor tracks on a multilayer printed circuit board. This has the advantage of enabling simple manufacturing, particularly mass production.

[0017] In a preferred embodiment, the winding is rectangular, square, or circular. An advantage of this design is that the winding shape can be adapted to the specific surrounding components. Furthermore, optimal utilization of the available surface area can be achieved.

[0018] According to the invention, the stack comprises layers of magnetizable material. An advantage of this is that the layers can be made thin, resulting in a stack with low mass. Material with low specific gravity, particularly plastic, can be used between the layers, allowing the stack to be flexibly adapted to a support component or to various other attachments. In particular, the stack can even be bonded to a surface that changes over time, for example, the surface of a part subjected to bending vibrations. The stack can be bonded to the part, especially the support component, using adhesive.

[0019] According to the invention, an amorphous iron alloy is used as the magnetizable material, in particular one which has a nanocrystalline structure, In particular, the relative magnetic permeability of the material exceeds 30,000, and especially has a value between 50,000 and 200,000. The advantage here is that high permeability is available with a simultaneously low material mass. The saturation field strength of the material exceeds 1 T, i.e., one Tesla. Preferably, it even exceeds 1.1 T. In this way, strong magnetic fields can be used in the inductive transformer.

[0020] According to the invention, a film made of polyethylene, polypropylene, or polyimide is arranged between each layer. An advantage of this is that inexpensive, easily manufactured films can be used, thus protecting the magnetizable material, especially ferromagnetic material, from environmental influences. In particular, corrosion is reduced or prevented.

[0021] According to the invention, the stack has adhesive layers such that the film is adhesively bonded to each layer, in particular on both sides. An advantage of this is that the stack can be easily manufactured in a single machine, where the films are unwound from a roll, thus simplifying the layering process.

[0022] In an advantageous embodiment, each layer has a thickness between 1 µm and 150 µm, measured in the stacking direction, and in particular a thickness between 15 µm and 50 µm. It is advantageous that the Weiss domains can be arranged essentially side by side in a planar arrangement. A further advantage is that the entry and exit of the field lines can occur perpendicular to the surface, and deviations from the ideal path can be prevented, thus reducing volume effects. This is because, in contrast to the invention, the field lines do not pass through in a perfectly straight line when using a ferrite material with a high wall thickness. With the thin layers according to the invention and the high permeability, the magnetic field lines pass through the layers essentially in a straight line parallel to the stacking direction. Furthermore, saturation occurs in a well-defined manner at high magnetic field strengths.In contrast, saturation in a solid, massive body occurs in an unpredictable manner.

[0023] According to the invention, the magnetic field generated by or penetrating the winding is at least partially guided by a coil core arrangement comprising the stack, in particular as a yoke, and one or more ferrite elements, in particular as inner or outer legs of the coil core arrangement, wherein the ferrite elements contact the stack and / or are adhesively bonded to it or potted with a potting compound. It is advantageous that, perpendicular to the stack, i.e., in the stack direction, ferrite elements can be used for additional field guidance, which interact with the stack. Stacks constructed in a similar manner to the first-mentioned stack, which are geometrically limited in such a way that they can be used as a yoke or legs, are not according to the invention.

[0024] In an advantageous embodiment, the winding is encased in potting compound, particularly in that the stack is bonded to the potting compound in a material-bonded manner. An advantage of this is that mechanical stabilization can be achieved, while simultaneously improved heat dissipation can be achieved by using a highly thermally conductive potting compound.

[0025] Further advantages arise from the dependent claims. The invention is not limited to the combination of features of the claims. For those skilled in the art, further meaningful combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent, in particular from the problem statement and / or the problem arising from a comparison with the prior art.

[0026] The invention will now be explained in more detail with the help of illustrations: In the Fig. Figure 1 shows a schematic setup of an exemplary embodiment.

[0027] In this arrangement, a winding 2, designed as a flat winding, is arranged on a stack 1, in particular a stack of foil. The stacking direction of the stack 1 is parallel to the winding axis of the winding 2.

[0028] The stack comprises layers arranged one behind the other in the stacking direction. These layers are made of magnetizable material, in particular ferromagnetic material. Each layer has a thickness, measured in the stacking direction, between 1 µm and 150 µm, particularly between 15 µm and 50 µm. The material used is an amorphous, nanocrystalline iron alloy. The relative magnetic permeability exceeds 30,000 and is preferably between 50,000 and 200,000.

[0029] In the stacking direction, a polyethylene film is placed in front of and behind each of these layers. An adhesive layer is placed between each layer and each polyethylene film. Thus, the layers are bonded to each other by adhesive.

[0030] The stack has a total thickness, measured in the stacking direction, between 1 mm and 50 mm. The number of parallel layers depends on the overall stack thickness. Preferably, all layers of magnetizable material have the same thickness. The adhesive layers and films also have the same thickness in the stacking direction.

[0031] The magnetic field generated by winding 2 penetrates the stack in the stacking direction and is guided along the layers until it exits the stack in the opposite direction to the stacking direction outside of winding 2.

[0032] Although winding 2 has no core, the magnetic resistance is reduced, at least in the area of ​​the stack. Ferrite material is therefore unnecessary in this area.

[0033] Instead of polyethylene, polyimide or polypropylene can also be used in further embodiments according to the invention.

[0034] In one embodiment of the invention, a ferrite core is inserted centrally in the winding, and ferrite material is also applied to the outside. In this way, an E-shaped coil core can be formed together with the stack. The stack, the yoke, the ferrite core, and the additional ferrite material each form one leg. In a rotationally symmetrical design, the ferrite material surrounds the winding on its outside as a hollow cylinder.

[0035] Due to its high relative magnetic permeability, the stack also exhibits good shielding properties. This means that essentially no magnetic field is detectable on the side of the stack facing away from winding 2.

[0036] To increase rigidity, the stack is arranged on a support element, in particular a support plate, and is preferably bonded by adhesive. This support element is preferably made of metal, so that high strength and good thermal conductivity can be achieved and the stack can thus be effectively cooled. Aluminum or steel are particularly suitable metals.

[0037] The winding 2 is potted with potting compound, which also binds the stack together in a material-coherent manner.

[0038] In another embodiment, PET films are used instead of polyethylene films.

[0039] Winding 2 can be used as an example of a winding for an inductive transformer, in particular as a secondary winding. The primary conductor can be designed as an elongated conductor, with the secondary winding, including the support element, being attached to a device movable along the primary conductor, in particular a rail-guided vehicle.

[0040] Alternatively, the primary conductor can be configured as a ring winding or other flat winding. In any case, winding 2 is inductively coupled to the primary conductor as the secondary winding.

[0041] Preferably, when designed as a ring winding or flat winding, the primary conductor also has a stack on the side facing away from the winding 2 and the stack 1, which is constructed in the same way as the stack 1 associated with the winding 2.

[0042] In a further embodiment of the invention, instead of the in Fig.In addition to the rectangular flat winding shown in 1, a circular flat winding or a differently shaped flat ring winding can also be used. Reference symbol list 1 stack 2 windings

Claims

[1] Coil arrangement for a system for inductive energy transmission, wherein the coil arrangement comprises a winding and a stack, wherein the winding axis is aligned parallel to the stacking direction, where the winding is a toroidal winding, wherein the stack comprises layers of magnetizable material, wherein an amorphous iron alloy having a nanocrystalline structure is used as the magnetizable material, where the relative magnetic permeability of the material exceeds 30 000, wherein a film of polyethylene, polypropylene or polyimide is arranged between the layers, wherein the stack has adhesive layers, so that the respective film is adhesively bonded to the layers on both sides, wherein the magnetic field generated by the winding or penetrating the winding is at least partially guided by a coil core arrangement which uses the stack as a yoke and a ferrite core centrally in the winding and has ferrite material on the outside, wherein the ferrite core and the further ferrite material each form a leg, wherein the ferrite core and the further ferrite material touch the stack and / or are adhesively bonded to it or potted with potting compound, wherein the stack is adhesively bonded to a steel carrier plate. [2] Coil arrangement according to claim 1, characterized by that the winding is carried out using conductor tracks of a multilayer printed circuit board. [3] Coil arrangement according to at least one of the preceding claims, characterized by that the winding is rectangular, square or circular. [4] Coil arrangement according to at least one of the preceding claims, characterized by that the relative magnetic permeability of the material has a value between 50,000 and 200,000. [5] Coil arrangement according to at least one of the preceding claims, characterized by that each layer has a layer thickness measured in the stacking direction between 1 µm and 150 µm, in particular a layer thickness between 15 µm and 50 µm. [6] Coil arrangement according to at least one of the preceding claims, characterized by that the winding is potted by means of potting compound, in particular wherein the stack is integrally connected to the potting compound.

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