Coil arrangement

Abstract

Coil arrangement comprising two windings which are arranged wound around a central leg of a coil core, wherein outer legs of the coil core at least partially surround the coil arrangement, wherein the outer legs and the central leg are connected at their respective first end region by means of a first yoke and at their respective second end region by means of a second yoke, wherein the windings are arranged spaced apart from one another, wherein the windings are arranged around the same winding axis which is aligned parallel to the central leg, wherein the torus-shaped space region generated by the spacing of the windings is partially filled with a ferrite part which is formed separately from the central leg and the outer legs, wherein the ferrite part is formed from several ferrite rods (4) wherein the rods are aligned perpendicular to the winding axis, wherein the ferrite rods (4) are formed as rods which are flattened on their longitudinal side.

Description

The invention relates to a coil arrangement, in particular an alternating current transformer, a use and an arrangement for contactless energy transmission. From EP 0 706 192 A1 a winding arrangement is known in which three windings are wound at least partially overlapping around coil core sections. From JP H10 - 163 046 A a transformer coil winding is known in which the main field has to overcome an air gap. From DE 954 901 B a transformer is known in which the main magnetic field does not essentially penetrate a coil core that is effective for the stray field. From DE 20 2005 008 726 U1 a transformer is known in which one of the windings comprises two legs of the coil core. From US patent 2006 / 0181384A1, a transformer is known in which a cuboid element of high impedance is fixed between two windings. A method for tuning an inductor is known from US 2008 / 0 068 118 A1. From GB 1 250 290 A an arrangement for tuning a high-voltage transformer is known. A noise filter inductor is known from JP H04 - 254 308 A. The invention is therefore based on the objective of further developing a coil arrangement in which the stray flux is to be specifically increased. According to the invention, the problem in the coil arrangement, in particular the alternating current transformer, is solved according to the features specified in claim 1. Important features of the invention in the coil arrangement, in particular an AC transformer, include, among others, that it has two windings which are arranged wound around a leg, in particular a middle leg, of a coil core, wherein the outer legs of the coil core at least partially surround the coil arrangement, wherein the outer legs and the leg are connected at their respective first end region by means of a first yoke and at their respective second end region by means of a second yoke, wherein the windings are arranged spaced apart from one another, in particular wherein the windings are arranged around the same winding axis, in particular which runs parallel to the leg, in particular in the direction of the winding axis, wherein the space area created by the spacing of the windings, in particular torus-shaped space area, is partially filled with a ferrite part, i.e. ferrite body, in particular with a separate ferrite part. An advantage of this design is that the windings are not wound tightly together; that is, the winding sections of the first and second windings are spaced apart, with the directly interposed space between the winding sections of the first and second windings being partially, but not completely, filled with ferrite. Preferably, the windings are aligned in parallel, have the same base area, and are designed as ring windings. In this way, the leakage flux between the windings can be increased. Furthermore, a particularly simple and quick-to-manufacture arrangement can be produced by using E-cores as coil cores and impeder cores as ferrite elements, i.e., ferrite bodies, to partially fill the spaces created by the spacing. Furthermore, it is advantageous that the leakage flux can be increased in such a targeted manner that the associated leakage inductance can be used to operate a current-to-voltage converter tuned to resonance. In particular, the leakage inductance can be dimensioned such that it forms a resonant circuit with a capacitor whose inductance is on the order of the main inductance. An advantage of this is that the stray flux can be specifically increased by means of the ferrite parts, especially impeder cores. In an advantageous embodiment, the coil core for guiding the main flux has two yokes: a central leg and an outer leg. The advantage here is that the construction of the coil cores is simple and cost-effective. In an advantageous embodiment, the coil core is made of two or more parts. An advantage of this is that an elongated structure is possible, i.e., one extending transversely to the winding axis or in the direction of connection between the upper and lower parts, i.e., the first and second windings. The direction of connection here is therefore the direction from the center of gravity of the first winding to the center of gravity of the second winding. Preferably, the transverse dimension is greater than the dimension in the direction of the winding axis or in the direction of connection from the center of gravity of the first to the center of gravity of the second winding. In particular, modules for assembling coil cores of different lengths in the transverse direction are thus readily available. In an advantageous embodiment, the ferrite part extends tangentially to the winding. The advantage here is that as much ferrite material as possible can be incorporated in the transverse direction, thus achieving the highest possible amplification of the leakage flux. In an advantageous embodiment, the ferrite section and the coil core are spaced apart. The advantage here is that an air gap is provided for the leakage flux, and thus the leakage flux only minimally affects the main flux, which is guided without an air gap in the ferrite. In an advantageous embodiment, the ferrite component is made so small that saturated operation of the coil core, particularly the center leg, is possible even when operating in a non-saturated state. An advantage of this is that the leakage flux accounts for only a small fraction of the magnitude of the main flux. In an advantageous embodiment, the windings are arranged on a coil former, in particular wherein the coil former is a one-piece plastic part. It is advantageous that the coil former can be manufactured as a plastic injection molded part. In a preferred embodiment, the windings are flat windings or ring windings. An advantage of this is the ease of manufacturing. In an advantageous embodiment, the coil core is composed of multiple parts, in particular an upper part and a lower part, wherein the upper and lower parts are manufactured identically, especially as an E-shaped part. An advantage of this is that simple manufacturing is possible by merely joining the E-cores together. The ferrite part can then be inserted laterally, i.e., in the direction of the normal to the plane formed by the E, into a space provided for this purpose, formed by the coil former and located between the winding sections. In an advantageous embodiment, an upper part of the coil core is composed of several parallel E-cores, the E-cores being stacked one behind the other in a direction perpendicular to the winding axis, and a lower part of the coil core is composed of several parallel E-cores, the E-cores being stacked one behind the other in a direction perpendicular to the winding axis. An advantage of this is that an elongated arrangement can be achieved, thus increasing the leakage flux by inserting a ferrite element, as long as possible, into the space between the winding sections. In an advantageous embodiment, the effective air gap length of the space created by the spacing of the windings is reduced to less than one-fifth, and in particular to less than one-tenth, by arranging the ferrite element. It is advantageous that the leakage flux, although passing through an air gap, is associated with a high magnetic resistance. In an advantageous embodiment, the ferrite element is formed from one or more ferrite rods, wherein the rods are oriented perpendicular to the winding axis, and in particular wherein the ferrite rods are impedance cores, and thus are designed to be suitable for welding. An advantage of this is that cost-effective standard parts can be used in a new application, namely in a transformer to increase the leakage flux strength. In an advantageous embodiment, the windings are configured as a two-chamber winding, in particular the coil former is designed such that the windings are configured as a two-chamber winding. An advantage of this is that the coil former keeps the two windings at a distance. In an advantageous embodiment, the coil former has a receiving area for the ferrite element, such that material from the coil former is arranged between the ferrite element and the windings. It is advantageous that the coil former creates the spacing and thus the gap. In an advantageous embodiment, the ferrite element and / or the ferrite rods are arranged to be slidably adjustable for fine-tuning the leakage inductance. The advantage here is that fine-tuning of the leakage inductance is possible. Key features of their use include the use of impedance cores as coil cores in coil arrangements. A further advantage is that components known from welding equipment can also be used to increase leakage inductance in transformers. Key features of the contactless energy transmission arrangement are that a secondary winding is inductively coupled to a primary conductor, wherein a first capacitance is connected in parallel or in series to the secondary winding such that the associated resonant frequency of the resonant circuit thus generated essentially corresponds to a frequency of a medium-frequency alternating current impressed into the primary conductor, in particular wherein the frequency is between 10 and 500 kHz, wherein a coil arrangement according to one of the preceding claims is used for inductive coupling and a leakage inductance of the coil arrangement with a second capacitance connected to the secondary winding on the output side is also tuned to resonance with the frequency, in particular by appropriate alignment, arrangement and dimensioning of the ferrite part, in particular to form an inverse gyrator arrangement.that is, to form a converter from current source-like to voltage source-like behavior. An advantage of this design is that the leakage inductance can be used in a resonant circuit that converts the current from the secondary winding, thus transforming it from a current source to a voltage source. The secondary winding is part of a resonant circuit through which the current flows. The leakage inductance is dimensioned and, due to the ferrite core, made large enough that the resonant circuit incorporating the leakage inductance is also tuned to the same resonant frequency and exhibits the same input current. The invention will now be explained in more detail with reference to the illustrations: Fig. 1 shows a schematic cross-section through an arrangement according to the invention. Fig. 2 shows the associated coil former 5. Fig. 3 shows an oblique view from the outside, with the windings hidden. The coil core has a core section 1 and 10, wherein the core sections are shaped in an E-shape, i.e. each has a yoke with two outer legs and a middle leg, the yoke connecting the first respective end regions of the legs. The two core sections (1, 10) are joined together with the other end regions of their legs facing each other, with the legs touching each other. Preferably, the core sections (1, 10) are of the same design. At least, however, the leg length, in particular the distance of the other end regions of the legs from the yoke, is the same, and in particular also their cross-section and / or length. The primary winding is arranged around the middle leg of the core section 1 and the secondary winding 3 is arranged around the middle leg of the core section 10, the windings being wound on the coil former 5 and spaced apart from each other in the winding direction, i.e. in the direction of the winding axis. In the space created by the spacing between primary winding 2 and secondary winding 3, at least one core section 4, in particular a ferrite rod, is arranged, such that this core section 4 can be operated in saturation when there is no saturation in the middle leg. If a higher field strength is present in the middle leg, some field lines of the leakage inductance pass by the core section 4 undisturbed. It is important that the air gap of the space area, i.e., the distance between the center leg and the outer leg of the E-core, is effectively reduced by the introduction of the ferrite parts 4, i.e., impeder cores, since the space area is not only filled with air or coil former material, but also partially with ferrite material from the ferrite parts 4. The effectively effective air gap is therefore less than one-fifth or even less than one-tenth of the original air gap. Ferrite rods 4 are not only suitable as cylindrical rods, but also, as claimed, rods that are flattened on their longitudinal side, since this further increases the stray flux. The coil former 5 is made in one piece and accommodates both windings, i.e. primary winding 2 and secondary winding 3. Therefore, it is important in the invention that the field lines of the stray field, unlike the field lines of the main field, do not run completely within the core material, in particular ferrite material. This also applies especially in the unsaturated region. The invention is therefore particularly easy to manufacture and, through the use of commercially available E-cores and commercially available impeder cores, can be produced cost-effectively. Impeder cores are typically used in welding, but are very well suited for the present coil arrangement. The present coil arrangement can also be used as a transformer with only two windings. In a further development, the coil arrangement can be implemented with multiple windings. Figure 4 shows an exploded view of another embodiment according to the invention. Here, the E-core 1 is replaced by a stack of identical E-cores. Likewise, the E-core 10 is replaced by such a stack. This allows for an elongated design of the coil assembly and thus a further increase in leakage flux. This is because the ferrite elements 4, which are accommodated in the receiving area of ​​the coil former 5, can also be made correspondingly long due to the elongated design, thus resulting in a corresponding increase in leakage flux. Reference symbol list 1 Core section 2 Primary winding 3 Secondary winding 4 Core part, in particular ferrite rod 5 Coil former 10 Core section

Claims

Coil arrangement comprising two windings which are arranged wound around a central leg of a coil core, wherein outer legs of the coil core at least partially surround the coil arrangement, wherein the outer legs and the central leg are connected at their respective first end region by means of a first yoke and at their respective second end region by means of a second yoke, wherein the windings are arranged spaced apart from one another, wherein the windings are arranged around the same winding axis which is aligned parallel to the central leg, wherein the torus-shaped space region generated by the spacing of the windings is partially filled with a ferrite part which is formed separately from the central leg and the outer legs, wherein the ferrite part is formed from several ferrite rods (4) wherein the rods are aligned perpendicular to the winding axis, wherein the ferrite rods (4) are formed as rods which are flattened on their longitudinal side. Coil arrangement according to claim 1, characterized in that the coil core has two yokes, a middle leg and an outer leg, for guiding the main flux. Coil arrangement according to one of the preceding claims, characterized in that the coil core is made in multiple parts. Coil arrangement according to one of the preceding claims, characterized in that the ferrite part and the coil core are spaced apart, and / or that the windings are arranged on a coil body (5), wherein the coil body (5) is a one-piece plastic part. Coil arrangement according to one of the preceding claims, characterized in that the windings are flat windings or ring windings. Coil arrangement according to one of the preceding claims, characterized in that the coil core is constructed in multiple parts, consisting of an upper part and a lower part, wherein the upper part and the lower part are manufactured in the same manner. Coil arrangement according to one of the preceding claims, characterized in that an upper part of the coil core is composed of several parallel arranged E-cores, wherein the E-cores are arranged stacked one behind the other in a direction perpendicular to the winding axis of one of the windings, wherein a lower part of the coil core is composed of several parallel arranged E-cores, wherein the E-cores are arranged stacked one behind the other in a direction perpendicular to the winding axis of one of the windings. Coil arrangement according to one of the preceding claims, characterized in that the windings are accommodated in two chambers of a single coil body. Coil arrangement according to one of the preceding claims, characterized in that the coil body (5) has a receiving area for the ferrite part, such that material of the coil body is arranged between the ferrite part and the windings. Coil arrangement according to one of the preceding claims, characterized in that the ferrite rods (4) are arranged slidably for fine adjustment of the leakage inductance.

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