Inductive power transfer with reduced electromagnetic interactions within a conductor arrangement

Abstract

Inductive power transmission with reduced electromagnetic interactions in a conductor arrangement. The invention relates to a conductor arrangement (90) for inductive power transmission, the conductor arrangement (90) comprising at least three coils (92, 94) arranged along a longitudinal axis (LO) and formed by at least one conductor, the conductor arrangement (90) comprising at least two winding heads (W) arranged opposite to each other, and wherein the conductor portions of each coil (92, 94) extend along each other and along the longitudinal axis (LO), in at least one of the two winding heads (W), the conductor portions of the first and second coils (92) extending along the longitudinal axis (LO) are arranged at a first distance (D1) from each other, the first distance (D1) being equal to or greater than zero, and the conductor portion of the third coil (94) extending along the longitudinal axis (LO) is arranged at a second distance (D2) from the conductor portions of the first and second coils (92), the second distance (D2) being greater than the first distance (D1). Furthermore, the invention relates to an inductive power transmission device (100) and a method for providing a conductor arrangement (90) for inductive power transmission.

Description

[0001] The present invention relates to a conductor arrangement, an inductive power transfer arrangement and a method of inductive power transfer, in particular a method of inductive power transfer with reduced electromagnetic interactions. The invention particularly relates to the field of inductive power transfer to a vehicle. The vehicle may be a land vehicle, such as a road vehicle (e.g. a car, truck or bus) or a rail vehicle, such as a train or tram.

[0002] An electric vehicle, in particular a rail vehicle, and / or a road car, can be operated by electrical energy, wherein the electrical energy is transmitted by inductive power transmission. Such a vehicle may comprise a circuit arrangement, which may be a traction system or part of a traction system of the vehicle, comprising a receiving device adapted to receive an alternating electromagnetic field and to generate an alternating current by electromagnetic induction. Furthermore, such a vehicle may comprise a rectifier adapted to convert the alternating current into a direct current. The direct current may be used to charge a traction battery or to operate an electric motor. In the latter case, the direct current may be converted into the alternating current by an inverter.

[0003] Inductive power transfer is done using two sets of windings, for example three-phase windings. The first set is mounted on the ground (primary winding) and can be powered by a wayside power converter (WPC). The second set of windings (secondary windings) is mounted on the vehicle. For example, for some trams with cargo underneath, the second set of windings can be connected underneath the vehicle. The second set of windings or the secondary side in general is often called a pick-up or receiver. The first set of windings and the second set of windings form a high frequency transformer to transfer the power to the vehicle. This can be done in both static (when the vehicle is not moving) and dynamic conditions (when the vehicle is moving).

[0004] Each of the first winding and the second winding represents a conductor arrangement which may be formed by a plurality of coils. Each conductor arrangement and in particular each coil may be formed by an electrical conductor, such as a cable, which may also be referred to as a phase conductor.

[0005] Due to the large gap between the primary and secondary windings, the operating behavior of the resulting transformer is different from that of a conventional transformer with a closed core and a small or negligible air gap. A larger air gap results in smaller mutual inductive coupling and larger leakage inductance.

[0006] The leakage inductance is usually taken as a series inductance with each coil of the corresponding conductor arrangement. In order to be able to transmit high power levels, it is necessary to use sufficient capacitance to compensate for the reactance of the inductor at the operating frequency (e.g. kilohertz). For the secondary side of the high-frequency transformer, the combination of the inductance (which includes the main inductance or mutual inductance and / or leakage inductance) and the capacitance (which may include compensation capacitance) forms a resonant circuit. If the impedance values ​​of the inductance and capacitance are selected so that the natural resonant frequency of the resonant circuit is equal to the operating frequency, perfect impedance cancellation occurs. Such a resonant circuit is said to be tunable. Examples of separately tuned circuits can be found, for example, in the applicant's previously published patent GB 2507533 A.

[0007] In case of multiple coils within the conductor arrangement, each coil may include a respective compensation capacitor, and it is generally desirable that each coil forms a tuned resonant circuit. Specifically, the coils should be tuned to the same operating frequency, or more generally, should be able to operate at a common operating point.

[0008] Firstly, this may be difficult to achieve since the coils are usually arranged close to each other within the conductor arrangement and there are electromagnetic interactions between the coils. It should be noted that such electromagnetic interactions may particularly involve and / or result in differences in the inductance of the coils since the magnetic fields of the coils influence each other.

[0009] Furthermore, due to temperature variations and / or aging, the tolerance of the compensation capacitance increases, thus changing the resonant frequency of the resonant circuit formed by each coil. In particular, when the coils differ from one another, for example in terms of the compensation capacitance in each circuit, this may have a different effect on the resonant behavior of each circuit, resulting in a detuning of the resonant circuit. As a result, the changed resonant frequency may no longer correspond to the operating frequency and the resonant frequencies of the other circuits. This detuning deviates from the overall performance and power transfer capabilities of the inductive power transfer system. Furthermore, the impedance on the secondary side reflected to the primary side of the transformer may become capacitive. This results in a leading current with respect to the voltage in the WPC, which is highly undesirable, since the leading current eliminates the soft switching condition of the semiconductor switches and significantly increases their power losses. Under such operating conditions, the WPC may overheat and shut down, interrupting the desired power transfer.

[0010] It is therefore an object of the present invention to improve the operability of a primary or secondary conductor arrangement, in particular with regard to achieving a desired resonant behavior.

[0011] This object is solved by the technical solution defined in the independent claim attached hereto. Advantageous embodiments are defined in the dependent claims. It should be noted that, if not mentioned or indicated otherwise, the features mentioned in the above introductory part of this specification may also be provided in the presently disclosed solution individually or in any combination thereof.

[0012] According to the basic concept of the invention, a technical solution is proposed herein for limiting undesired electromagnetic interactions between coils of a conductor arrangement for inductive power transmission. In other words, the invention enables at least partial electromagnetic decoupling of at least some of the coils. As a result, the inductances of the coils can be kept at similar levels. In this way, similar operating points and resonant frequencies of the circuits can be achieved.

[0013] Furthermore, the inventors have observed that the above-mentioned detuning is particularly counterproductive in view of the electromagnetic interactions between the coils of the conductor arrangement. In particular, in the event that one coil experiences a relatively strong detuning, this may affect the other coils by electromagnetic interactions, thus leading to a further detuning of the entire conductor arrangement. Since the interactions are limited with the help of the present invention, this can be limited or even prevented.

[0014] Decoupling can be achieved by increasing the magnetic permeability around at least one coil so that the electromagnetic field generated by said coil can be concentrated near it and / or can be directed in a desired manner to limit the impact on other coils. For example, by creating closed field lines of finite length, the electromagnetic field, in particular its magnetic flux, can be kept close to the coil from which it originates.

[0015] Alternatively, this can be achieved by reducing the magnetic permeability around the coil (e.g. by providing a significant air gap), thereby limiting the extent to which the magnetic flux of the coil can affect adjacent coils (e.g. not easily transferred or not reachable). For example, the distance of a coil to other coils can be locally increased in at least one direction. According to some embodiments, this distance can be used to position the magnetizable material in the resulting gap to achieve the above-mentioned increased magnetic permeability. In this way, by combining the advantages of the two permeability strategies described above, unwanted interactions can be particularly reliably prevented.

[0016] It should be noted that in this context, magnetic permeability may be understood as the ability of a coil surrounding to support the formation and / or expansion of a magnetic field originating from a corresponding adjacent coil.

[0017] By limiting the electromagnetic interactions between the coils in this way, the risk of detuning can be limited and it can generally be easier to maintain a common operating point for all coils. In particular, the risk of uncontrolled detuning of any coil may be limited as soon as one coil is affected by ageing or temperature.

[0018] It has further been found that the introduction of the above-mentioned measures in so-called winding heads is particularly effective, for example because the coils in these areas are in close proximity. Furthermore, the magnetic flux in the winding heads can be greater, for example 3 to 5 times greater than in the central part of the conductor arrangement (i.e. the part containing the active part discussed below). This can be due to the higher concentration of ferrite or other magnetizable materials at the winding heads, for example due to the provision of known electromagnetic shielding components in this area. Therefore, when the inventive measures for electromagnetically decoupling the coils from one another in the area of ​​the winding heads are provided, detuning can be limited particularly well.

[0019] More specifically, a conductor arrangement for inductive power transmission (e.g. to a land vehicle, such as a train or a road vehicle) is proposed herein. The conductor arrangement comprises at least three coils arranged along a longitudinal axis (e.g. adjacent to each other) and formed by at least one conductor (preferably each coil is formed by a separate conductor), the conductor arrangement comprises at least two winding heads arranged opposite to each other and wherein the conductor portions of each coil extend along each other and along the longitudinal axis, in at least one of the two (or each) winding heads, the conductor portions of a first coil and a second coil extending along the longitudinal axis are arranged at a first distance from each other, the first distance being equal to or greater than zero, and the conductor portion of a third coil extending along the longitudinal axis is arranged at a second distance from the other conductor portions (i.e. the conductor portions of the first and second coils extending along the longitudinal axis), the second distance being greater than the first distance.

[0020] In other words, the conductor portions of the first and second coils are positioned closer to each other than the conductor portion of the third coil. The second distances may be equal to each other and are generally non-zero. If a second distance is mentioned only in the singular in the following, two second distances may be involved if not mentioned or indicated otherwise. As an alternative to defining two second distances, the second distance may be defined as involving the distance between the first and third coil, while the third distance may involve the distance between the second and third coil, which distances are also greater than the first distance.

[0021] In other words, two of the conductor portions (the conductor portions of the first and second coils) may be close to each other or even located at the same position along a defined axis (the first distance), while the other conductor portion (the conductor portion of the third coil) is located at a greater distance compared to the first distance. It should be noted that the distance of the other conductor portion to any conductor portion of the first and second coils may be greater than the first distance.

[0022] The second distance may be at least 1.5 times the first distance, or at least twice, at least, at least five times, at least ten times, or up to twenty times the first distance. Additionally or alternatively, the first distance may be less than 10%, less than 5%, or less than 2% of the length of the longitudinal portion of the coil within the winding head, and the second distance may be greater than that length (e.g., 1.5 times the first distance).

[0023] In general, the first distance and the second distance may be selected so that the characteristics of the coils are comparable (e.g. by limiting undesired interactions accordingly). Such characteristics may be inductance, resonance behavior, amplitude and / or frequency of the induced current, etc. In this context, the coil having the larger second distance from the remaining coils may be the coil that is exposed to the most and / or largest interactions with the other coils, e.g. located between them (see below).

[0024] It should be noted that in the present disclosure, if reference is made to conductor sections of a coil, in particular to conductor sections of a coil within a winding head, this may generally relate to conductor sections extending along the longitudinal axis, even if this may not be mentioned in each of the following cases. Therefore, when reference is made below to conductor sections within a winding head, transverse conductor sections that may be included in the winding head or at least lead to the winding head may not be taken into account.

[0025] Furthermore, the extension of such a conductor portion along the longitudinal axis is not limited to (but may optionally be) a straight line extension parallel to said axis, but rather, a conductor portion may be considered to extend along said axis as long as one directional component (e.g. a vector) and preferably the main directional component of its extension extends along said axis. This relates, for example, to elliptical coils or generally curved extensions of conductor portions within a winding head. Thus, as long as the conductor portion does not extend along a transverse axis extending perpendicular to the longitudinal axis (or extends only to a less dominant extent), the conductor portion may be considered to extend along the longitudinal axis. Similarly, any conductor portion may be considered to extend along the longitudinal axis when it connects two conductor portions and / or two regions of the coil that are spaced apart from each other along the longitudinal axis. This may be valid even for an exact route or extension of the conductor portion extending between the portions or regions to be connected.

[0026] The winding head may generally be a region in which the extension direction of the coil is reversed, for example reversed when viewed in the winding direction. For example, a conductor may enter a winding head extending upward and leave a winding head extending downward towards an opposite winding head.

[0027] The coil may also be referred to as a phase winding or a pole of a conductor arrangement. In general, the coil may comprise at least one completely closed or mostly closed loop or winding formed by a conductor. For example, the opening angle of the loop or coil may be equal to or less than 90° and thus largely closed. The coil may comprise a plurality of completely closed or mostly closed turns (e.g. at least two per coil). The opening angles or opening portions of the turns may be positioned so as not to overlap each other (e.g. positioned on different sides, preferably opposite sides, of the coil).

[0028] The coils may be formed by conductors. Preferably, at least some of the coils (preferably all coils) are formed by separate conductors (i.e. one conductor per coil). The conductors may also be referred to as phase lines and / or may be cables. Typically, each coil may generate one phase of an alternating three-phase current (secondary side) or be operated by one phase of an alternating three-phase current (primary side).

[0029] The conductor arrangement has a longitudinal axis and preferably has a transverse axis extending at a certain angle, for example the transverse axis is perpendicular to the longitudinal axis. Both axes can extend in the plane in which at least one coil is formed or extend parallel to the plane. It should be noted that the "plane in which the coil is formed" can relate to any main plane in which the coil is formed, for example a plane comprising at least 50% of the area covered or surrounded by the coil and / or comprising at least 50% of the conductor length of the coil. Additionally or alternatively, the expressions quoted above can relate to the coil plane extending between the winding heads and / or the coil plane comprising the active part of the coil, which is discussed in further detail below.

[0030] The coils may be arranged side by side with each other along the longitudinal axis (e.g. when the conductor arrangement is viewed along said longitudinal axis), or in other words, may be displaced relative to each other along the longitudinal axis. This may include a distance, spacing or space between at least some of the coils. However, preferably, the coils at least partially overlap each other, so that being arranged adjacent to each other along the longitudinal axis may also include partial overlap, as long as the order of the coils is apparent when viewed along said axis. Preferably, there is no corresponding displacement of the coils along the transverse axis.

[0031] Typically, the centers of the coils (e.g., geometric centers and / or centers of the areas enclosed by the coils) may be arranged adjacent to each other along the longitudinal axis, but preferably with a distance between them. The distance may be equal to at least one quarter of the size of at least one of two adjacent coils along the longitudinal axis, such as about half or one third of the size. Furthermore, the centers are preferably arranged along a common straight line, which is preferably consistent with or extends along the longitudinal axis.

[0032] Each coil can be shaped in a rectangular or oval manner and preferably each coil has the same size and / or shape. Each coil can have two pairs of parts arranged opposite to each other and / or in parallel, one pair being part of the winding head and the other pair being the so-called active part. Additionally or alternatively, each coil can have two (relatively) long parts and two (relatively) short parts, the longer parts preferably extending opposite to each other and / or in parallel, preferably this also applies to the shorter parts. The longer parts can be active parts and the shorter parts can be part of the winding head.

[0033] The active part of the coil may define or govern the characteristics of the coil with respect to inductive power transfer. Additionally or alternatively, the active part may be configured to generate a resonant electromagnetic field during inductive power transfer by interacting (and / or cooperating) with a further conductor arrangement (e.g. positioned at the respective other of the primary side and the secondary side). Typically, the active part may be formed or provided by a longer part of the coil and / or at least a part of a so-called pole branch of the coil. The active part may extend along a transverse axis of the conductor arrangement and / or be connected by further parts (shorter winding heads) extending along a longitudinal axis of the conductor arrangement.

[0034] In summary, each coil may therefore have a portion or segment extending along and / or parallel to one of the longitudinal axis and the transverse axis (particularly two portions along the longitudinal axis and two portions along the transverse axis). The portion extending parallel to the transverse axis may also be referred to as an active portion. The transverse axis is preferably orthogonal to and intersects the longitudinal axis.

[0035] The coils can be provided as substantially flat structures. Therefore, they can be arranged in a common two-dimensional plane and / or parallel to a common two-dimensional plane. The plane can include the above-mentioned transverse axis and longitudinal axis of the conductor arrangement. It should be understood that if extended in a common plane, the plane can have a limited thickness, for example, a thickness defined by the conductor (for example, its diameter). On the other hand, at least at a position where two coils overlap, stack or cross, the thickness of the plane can be defined by the thickness of the conductor or a corresponding multiple of its diameter, for example because at a corresponding intersection, a plurality of conductor portions are superimposed on each other.

[0036] According to known technical solutions, at least part of the conductor parts of the coil forming the winding heads can be placed at a different (e.g. vertical) height than those conductor parts forming the active part of the coil. For example, these different conductor parts can be angled relative to each other. In this case, the thickness of the plane in which the coil is formed can include two height levels, or, as mentioned above, the plane in which the coil is formed can relate to the (main) plane extending between the winding heads and thus including the active part.

[0037] Typically, both the transverse and longitudinal axes may be oriented perpendicular to the vertical axis, which is preferably oriented toward the other of the first side and the secondary side and / or extends parallel to the main direction of power transmission. In addition, the vertical axis may be oriented along the direction of gravity, but is preferably oriented opposite thereto. Directional terms used in this disclosure refer to directions such as "above", "below", "beside" or their respective synonyms, and may relate to the aforementioned longitudinal, transverse and vertical axes.

[0038] It should be noted that references to the first, second and third coils are generally interchangeable if not mentioned or otherwise specified (i.e. the terms first, second and third do not define a different order). However, in a preferred embodiment, one of the coils is located between the other coils along the longitudinal axis, i.e. the third coil is arranged at a greater distance from the other coils.

[0039] More precisely, according to one embodiment of the device and the method, the third coil is at least partially arranged between the first coil and the second coil when viewed along the longitudinal axis. This is advantageous because the (center) coil may be most affected by electromagnetic interactions with other (external) coils. Therefore, decoupling the center coil from the external coils by the measures of the invention is particularly advantageous because the overall electromagnetic interactions within the conductor arrangement can be significantly reduced.

[0040] In general, the first and second distances may be measured along any (common) axis, and according to the following embodiments, in particular along a vertical axis or a horizontal (eg lateral) axis.

[0041] Specifically, according to one aspect of the device and method, the first distance and the second distance extend along an axis parallel to a plane in which at least one coil is formed. The plane may be a principal plane as described above. In addition, the plane may be a horizontal plane extending perpendicular to a vertical (space) axis. On the other hand, the axis along which the distance is measured may be a transverse axis as described above. Therefore, according to this embodiment, a horizontal displacement of the coil may be provided.

[0042] Thus, along the axis and within the winding head, two coils or their conductor portions, respectively, can be preferably arranged at the same position (e.g. at the same lateral position), whereas the conductor portion of the third coil can be arranged at a different lateral position compared to the other conductor portions. In particular, the different lateral position can be located further inwards and / or closer to the geometric center of the conductor arrangement with respect to the geometric center.

[0043] For example, the conductor parts of the first and second coils may form an outer part of the winding head, and the conductor part of the third coil may form an inner conductor part. The inner conductor part may for example face the opposite winding head, or in other words be located closer than the outer part.

[0044] In this case, the third coil can have a reduced lateral dimension (or in other words a reduced height) compared to the first and second coils, said lateral dimension extending between the winding heads. In particular, the lateral dimension can be measured along a transverse axis as described above, which preferably extends orthogonally to the longitudinal axis. When considering the actual relevant dimensions of the coil, this may not have a significant effect on the characteristics of the coil, for example in terms of the induced current. However, it may also be attempted to compensate for this limited size by adjusting other measures and / or characteristics of the third coil accordingly. To this end, the conductor of the third coil (for example its diameter) and / or the longitudinal dimension along the longitudinal axis can be adjusted and in particular increased.

[0045] Alternatively, the first distance and the second distance may extend along an axis that is not parallel to the plane in which at least one coil is formed. In particular, the first distance and the second distance may extend along a vertical axis. For example, the conductor portions of the first to third coils may be arranged on top of each other in the winding head, or in other words, placed on top of each other. However, they may be spaced apart from each other at different distances. In particular, two of the coils (the first and second) may be arranged close to each other, while the remaining (third) coil may be arranged at a larger (second) distance therefrom. In this way, the electromagnetic interaction between the third coil and any one of the first and second coils may be limited.

[0046] As mentioned above, the first distance and the second distance may thus generally be vertical distances, ie they may be measured along a vertical axis.

[0047] According to another embodiment of the device and the method, in each winding head, the magnetizable material is arranged between the conductor portion of the third coil and the conductor portion of one of the first and second coils. Specifically, the magnetizable material can be arranged between the third coil and the coils adjacent to the first and second coils, respectively. To this end, it is particularly beneficial to increase the distance of the third coil to the remaining coils.

[0048] Typically, the magnetizable material allows to guide the electromagnetic field in a desired manner, more precisely, to guide the magnetic flux of adjacent coils, since it is not completely permeable to the magnetic flux. Instead, the magnetic flux can be guided at least partially in the direction of the magnetizable material. Thus, the magnetizable material can contribute to concentrating the magnetic flux near each coil, thereby magnetically shielding adjacent coils from each other. Preferably, this is done in such a way that closed and / or short magnetic field lines are formed. Furthermore, the magnetizable material can avoid or at least limit the magnetic fields of adjacent coils from crossing each other, for example by guiding the magnetic flux, in particular the magnetic field lines of each electromagnetic field, accordingly.

[0049] In one example of the apparatus and method, the magnetizable material is arranged to facilitate the formation of closed magnetic field lines around the third coil. Additionally or alternatively, the magnetizable material may be arranged to facilitate the formation of closed field lines of the first and / or second coils. To this end, the magnetizable material may form a protrusion extending between the third coil and at least one of the first and second coils. The protrusion may, for example, protrude in the direction of the transverse axis and / or extend along the longitudinal axis with a defined length (e.g., at least half of the length of the winding head). Typically, the magnetizable material may surround at least one (preferably both) of the third coil and / or the first and second coils on at least two sides (preferably on three sides) within the winding head.

[0050] Typically, the magnetizable material may have a low electrical conductivity and may be, for example, a ferrite. Thus, the effect of currents induced in the shielding material is reduced.

[0051] More generally, the magnetizable material may be ferromagnetic, paramagnetic or ferrimagnetic. Preferably, the magnetizable material has a magnetic susceptibility of at least 10, preferably at least 50.

[0052] In another embodiment of the device and method, the magnetizable material is arranged between the respective conductor portions when viewed along an axis that is not parallel to the plane in which the at least one coil is formed.

[0053] As described above, according to embodiments of the arrangement and method, the magnetizable material is formed as a protrusion. The protrusion may extend at least partially in a direction parallel to a plane in which at least one coil is formed (or more specifically, may protrude in this direction). For example, the protrusion may protrude horizontally into a space formed between the third coil and at least one of the first coil and the second coil.

[0054] According to one aspect of the device and method, the magnetizable material is part of a shielding assembly extending along each winding head. The shielding assembly can generally be configured to shield the surrounding environment from the influence of the electromagnetic field generated by the conductor device. Examples of various shielding assemblies can be found, for example, in the applicant's earlier published patent EP 2 841 293B1. It may be beneficial in terms of cost because the magnetizable material extending between the conductor parts can be directly arranged at the shielding assembly and / or formed as part of the shielding assembly. Therefore, no additional bearing member of the fixing device is required to position the magnetizable material in a desired manner.

[0055] In order to further limit production costs, it is preferably possible to provide an integral one-piece design, wherein the magnetizable material (e.g. protrusions) is arranged between the conductor parts in the manner described above, forming part of a shielding component of a larger piece. For example, it may protrude from an elongated shielding component, e.g. extending longitudinally along the winding head. In addition to the material arranged between the conductor parts, the elongated shielding component may have a C-shaped, U-shaped or L-shaped cross-section so as to cover the outside and / or upper part of the conductor arrangement and its sides.

[0056] Additionally or alternatively, within each winding head, the magnetizable material may be placed opposite to a side of the conductor portion of the third coil, the side facing away from the first and second coils. In other words, the side of the conductor portion of the third winding within each winding head that faces outward (particularly the other of the primary side or the secondary side) may be covered and / or shielded by the corresponding magnetizable material. Furthermore, with respect to the vertical axis, the magnetizable material may be located below the conductor portion of the third coil. Furthermore, the corresponding magnetizable material may be positioned vertically above the first and / or second coil. Each of these materials above and below the coil may be connected to each other by another portion of the magnetizable material, thereby forming an overall C-shaped profile.

[0057] This can preferably be done by a horizontal protrusion of such material, which can extend parallel to the corresponding material in case the corresponding material is also positioned between the conductor parts in the above-described manner. The corresponding material can form a horizontal branch of the cross-sectional profile of the shielding assembly, such as the lower branch of a corresponding C-shaped profile or an E-shaped profile. It should be noted that when the magnetizable material is provided between the conductor parts in the above-described manner, an E-shaped profile can be achieved, wherein the material forms a middle branch or a middle protrusion of the E-profile. Because, in some aspects, the shielding assembly can have an E-shaped cross-sectional profile.

[0058] Any profile mentioned here may be a cross-sectional profile of the shielding assembly. The plane of the cross section may extend orthogonally to the conductor portion within the winding head and / or to a horizontal spatial plane.

[0059] The invention also relates to a conductor arrangement comprising at least three coils which are arranged along a longitudinal axis and are formed by at least one conductor, the conductor arrangement comprising at least two winding heads which are arranged opposite one another and in which the conductor sections of each coil extend along one another and along the longitudinal axis, and a magnetizable material is placed between at least two conductor sections in at least one winding head.

[0060] The conductor arrangement may include any of the features, embodiments and aspects discussed above or below with respect to the conductor arrangement including the first distance and the second distance. In particular, any of the definitions, explanations, embodiments and variations discussed above with respect to features of similar terms may also be applicable to the conductor arrangement including a magnetizable material.

[0061] In particular, the magnetizable material may be placed between a conductor portion of the third coil as discussed above (e.g. a coil arranged between further coils along the longitudinal axis) and one of the first and second coils. Furthermore, the magnetizable material may be formed, for example, as a horizontal protrusion. However, the difference is that, in contrast to the conductor arrangement comprising a first distance and a second distance, such unequal spacing of the conductor portions within the winding head is not mandatory. On the contrary, it has been determined that even in the case of equal or substantially different spacings of the conductor portions, the advantages of the invention can be at least partially achieved when the magnetizable material is arranged between at least two conductor portions (e.g. vertically between them), in particular between those segments extending along the longitudinal axis.

[0062] The present invention also relates to an inductive power transfer device, comprising a primary side configured to generate an electromagnetic field and a secondary side configured to receive the electromagnetic field, thereby generating magnetic induction on the secondary side, wherein at least one of the primary side and the secondary side comprises a conductor arrangement according to any of the preceding claims. The primary side and the secondary side may generally be configured according to any of the examples discussed above and below. For example, the primary side may be fixed, such as provided in the surrounding environment, while the secondary side may be movable, such as provided on a vehicle. It should be noted that, as a general aspect of the present invention, the conductor arrangement disclosed herein may be used for any of the primary side and the secondary side, and limiting electromagnetic interactions between coils on the secondary side may be particularly beneficial.

[0063] In summary, the secondary side may be arranged on the land vehicle, and the primary side may be arranged around the land vehicle (eg, the ground on which the land vehicle moves).

[0064] The present invention also relates to a method for providing a conductor arrangement for inductive power transmission, the method comprising forming at least three coils of the conductor arrangement such that the coils are arranged along a longitudinal axis, and such that at least two winding heads are formed which are arranged opposite to each other and in which conductor portions of each of said coils extend along each other and along said longitudinal axis, and such that in at least one of the two winding heads, said conductor portions of a first and a second coil extending along said longitudinal axis are arranged at a first distance from each other, said first distance being equal to or greater than zero, and said conductor portion of a third coil extending along said longitudinal axis is arranged at a second distance from another conductor portion, e.g. said conductor portion of said first and second coils, said second distance being greater than said first distance.

[0065] The invention also relates to a method of providing a conductor arrangement for inductive power transmission, the method comprising forming at least three coils of the conductor arrangement such that the coils are arranged along a longitudinal axis, such that at least two winding heads arranged opposite to each other are formed and wherein conductor portions of each of said coils extend along each other and along said longitudinal axis, and such that a magnetizable material is placed between at least two conductor portions within at least one of said winding heads (e.g. extending along the longitudinal axis).

[0066] The method may include any further steps, any improvements or any further features to provide any interactions, operating states and functions discussed before and after. Specifically, any previous and subsequent explanations and improvements about device features may also be applicable to equivalent method features. In general, these methods may be implemented and / or performed using devices according to any of the previous and subsequent examples.

[0067] Embodiments of the present invention will be described below with reference to the accompanying drawings. Throughout the accompanying drawings, features that correspond to each other in terms of their type and / or function may be assigned the same reference numerals. In the accompanying drawings:

[0068] Figure 1 is a schematic diagram of an inductive power transfer apparatus according to an embodiment of the present invention;

[0069] Figure 2 yes Figure 1 A schematic diagram of the secondary side or device;

[0070] FIG3 is a detailed view of a secondary side winding head of the prior art;

[0071] Figure 4 yes Figure 2 Detailed view of the secondary winding head;

[0072] Figure 5 is a detailed view of a secondary side winding head according to another embodiment of the present invention;

[0073] Figure 6 is a detailed view of a secondary side winding head according to yet another embodiment of the present invention; and

[0074] Figure 7 yes Figure 6 A top view of a portion of an implementation scheme of.

[0075] exist Figure 1, an inductive power transfer device 100 according to an embodiment of the present invention is schematically shown. The inductive power transfer device 100 is configured to inductively charge an electric vehicle 4. The vehicle 4 includes wheels 7a, 7b for traveling on a track 2. For example, the vehicle 4 may be a road vehicle (e.g., a private car or bus) or may be a tracked vehicle, such as a rail vehicle. The details of the road or rail are not shown. Figure 1 Shown in.

[0076] There is provided an arrangement of conductive material combined with (e.g. embedded in) a track 2. For example, there are three-phase conductors 1a, 1b, 1c for carrying three phases of a three-phase alternating current during operation. The phase conductors 1a, 1b, 1c form a conductor arrangement 90, wherein each of the phase conductors 1a, 1b, 1c is a coil 92, 94 (see below) Figure 2 for discussion).

[0077] Together with the conductive material embedded in or as part of the track 2, the conductor arrangement 90 forms the primary side 102 of the inductive power transfer device 100, or in other words, the primary side conductor assembly. During operation, the primary side 102 generates an electromagnetic field. The magnetic field lines F are schematically shown in Figure 1 However, the field lines F are not completely shown. Instead, only the nearly uniform region of the magnetic field in the gap between the primary side 102 and the secondary side 104 of the onboard power transmission device 100 of the vehicle 4 is shown by the magnetic flux lines.

[0078] The vehicle 4 comprises a receiver 4b for receiving an electromagnetic field and for generating electrical energy by magnetic induction. For this purpose, the receiver 4b comprises a secondary side 104 or in other words a secondary side conductor assembly of the device 100. In the specific embodiment shown, this secondary side 104 comprises three phase lines 5a, 5b, 5c for generating a three-phase alternating current. The phase lines 5a, 5b, 5c may be coils comprising several windings of an elongated electrical conductor, thus representing the coils 92, 94 of the conductor device 90 described above. Optionally, each phase line 5a, 5b, 5c may comprise or more accurately be formed as a plurality of coils.

[0079] like Figure 1 An energy storage device 4a for storing the electrical energy generated by the receiver 4b is also schematically shown. Other electrical and / or electronic components may be used to provide the generated electrical energy to any vehicle 4 that consumes electrical energy, not shown in FIG. Figure 1 Shown in.

[0080] like Figure 2 Schematically shows Figure 11 is a top view or bottom view of the primary side 102 or the secondary side 104 of the inductive power transmission device 100. In particular, it shows a top view or bottom view of the conductor arrangement 90 on the respective primary side or secondary side 102, 104. The direction of connecting the primary side and the secondary side (i.e., as shown in FIG. Figure 1 The direction of the magnetic flux F extending therebetween is shown to be perpendicular to Figure 1 In addition, Figure 1 In the embodiment, the outer members 5c, 5a and 1c, 1a of each conductor arrangement 90 correspond to Figure 2 The outer coil 92, and the central member 5b, 1b corresponds to Figure 2 The center coil 94.

[0081] exist Figure 2 In FIG. 1 , the longitudinal axis LO is shown. The axis LO will be Figure 1 2, extending from left to right, for example parallel to the rail 2. In addition, a transverse axis LA extending orthogonally to the longitudinal axis LO is shown. Figure 1 , the horizontal axis LA will extend orthogonally to the plane of the figure, e.g. towards the viewer. The horizontal and longitudinal axes LA, LO extend in or define a horizontal plane. It should be noted that the horizontal plane corresponds to the plane in which at least the active part A of the coils 92, 94 is formed. As mentioned above, this can be considered as the (main) plane in which the coils 92, 94 are formed. Furthermore, the vertical spatial axis Z extends orthogonally to both the horizontal and longitudinal axes LA, LO and faces Figure 2 Observer. It should be noted that Figure 1 , the orientation of the vertical axis Z is also depicted.

[0082] The coils 92, 94 are each marked by a different line. Specifically, the outer coil 92 is marked by a dashed line, while the center coil 94 is marked by a solid line. It can be seen that each coil is formed as an elliptical or rectangular closed electrical conductor device, which is a cable. The coils 92, 94 have similar shapes and sizes but are not arranged congruently. Instead, they are displaced relative to each other along the longitudinal axis LO, but are arranged at the same height along the transverse axis LA.

[0083] Each coil 92, 94 includes two longer conductor portions extending along the transverse axis LA and two shorter conductor portions extending along the longitudinal axis LO, each pair of corresponding pairs of conductor portions being parallel to and opposite to each other. The conductor portions extending along the transverse axis LA each form an active portion A of the corresponding coil 92, 94 and thus form an active portion A of the entire conductor arrangement. The conductor portions extending along the longitudinal axis LO form two opposite winding heads W connecting the active portions A. Specifically, the active portions A are spaced apart from each other along the longitudinal axis LO. However, they are connected by the conductor portions of the winding heads. Due to the longitudinal gaps between the bridging active portions A, the conductor portions of the winding heads extend along the longitudinal axis LO, even though they may be curved in the case of elliptical windings. For further explanation, in Figure 2 The winding head W of a larger area is circled in the figure. However, strictly speaking, only the area where the short conductor parts of each three coils 92, 94 extend along each other can be considered to represent the actual winding head W. This corresponds to the area of ​​the short longitudinal conductor part of the center coil 94 in each of the said surrounding areas. It should be noted that in the context of the embodiment, only those conductor parts extending along the longitudinal axis LO are referred to as "conductor parts in / of the winding head".

[0084] Therefore, in Figure 2 In the example of , the coils 92 , 94 are arranged at the same position (ie height) along the transverse axis LA. However, they are arranged sequentially and in particular adjacent to each other along the longitudinal axis LO.

[0085] In more detail, each coil 92, 94 shows a geometric center 92M, 94M, or in other words, the center of the area of ​​the coil 92, 94 (i.e., the center of the area surrounded by the coil 92, 94). It can be seen that the central coil 94 is arranged between the outer coils 92 (especially between the geometric centers 92M of these outer coils 92) along the longitudinal axis LO, especially with respect to its geometric center 94M.

[0086] Thus, the coils 92, 94 and in particular their geometric centers 92M, 94M are spaced apart from one another, or in other words, displaced relative to one another along the longitudinal axis by an equal distance (eg, one third of the longitudinal dimension (ie, width) of each coil 92, 94).

[0087] As Figure 2 As a general result of the conductor arrangement depicted in , each coil 92 , 94 forms a coil that can generate a different phase of a three-phase alternating current during operation or a coil that can carry one phase of a three-phase alternating current, depending on which of the primary side or the secondary side 102 , 104 is considered.

[0088] Furthermore, in Figure 2, a shielding assembly 96 made of magnetic material is shown. As will become apparent from the following figures, the shielding assembly 96 can also cover at least a portion of the winding head W (relative to the axis Z) or extend below it. Furthermore, even if the shielding assembly 96 is only depicted as being outside the winding head W and extending along the winding head W, it can also completely surround the conductor arrangement 90 on all sides. For example, due to the connection via additional transverse sections (not shown) Figure 2 In the longitudinal section depicted in FIG. , it may have an overall rectangular outline. In addition, at least a portion of the shielding assembly 96 may extend along a side of the conductor arrangement 90, which faces away from the other conductor arrangement 90 at the respective other side of the primary side or the secondary side 102, 104. An example of a shielding assembly 96 can be found in the above-mentioned earlier published EP 2 841 293 B1.

[0089] In the following, a cross section of a conductor arrangement 90 according to an embodiment of the present invention will be discussed. The plane of the cross section contains the horizontal axis LA and the vertical axis Z or extends parallel to the horizontal axis LA and the vertical axis Z. In addition, the cross section depicts only one of the winding heads W. However, it should be understood that the winding heads W that are respectively opposite are configured in a similar manner. This is represented by the symmetry axis S in the following figure, in which the components and assemblies depicted are mirror images. Further, the following cross section relates to the secondary side 104, but the primary side 102 can be configured in the same manner (for example, by simply inverting the conductor arrangement 90 depicted).

[0090] First, however, an example of a prior art solution is shown in Figure 3. More precisely, the figure shows a cross section of a winding head W of a prior art conductor arrangement 90. The different coils 92, 94 are formed by Figure 2 3 . A portion of the active portion A of the coils 92, 94 can be seen. In the region of the winding head W, the conductor portion of the coils 92, 94 is angled relative to the active portion A and extends into the plane of FIG. 3 towards the opposite active portion A (i.e., a point away from the observer).

[0091] In a generally known manner, the conductor parts of each coil 92, 94 are placed vertically on top of each other, or in other words, are stacked vertically (see the respective vertical axis Z). Adjacent conductor parts in the winding head W are therefore spaced vertically apart from each other. This spacing is regular, i.e. the conductor parts have the same vertical distance from the corresponding directly adjacent conductor parts. In addition, in the case of contact between adjacent conductor parts, the distance is relatively small (e.g. a few centimeters) or does not exist. If contact is not required, for example a plastic spacer or other electrically insulating material can be arranged between adjacent conductor parts.

[0092] Furthermore, the figure shows a shielding assembly 96 comprising a magnetizable material 110. The shielding assembly 96 covers (vertically) the upper side of the conductor arrangement 90. Close to the lateral edges, it has enlarged corners 112 for receiving the winding head W. It should be noted that the shielding assembly 96 also covers the lateral outer edges or in other words the sides 114 of the winding head W.

[0093] 3 also shows the main routes of magnetic field lines 116 generated in the region of the winding head W, which appear when the conductor arrangement 90 is operated (i.e., when electrical energy is inductively transferred thereto). Due to the shape of the shielding assembly 96, most of the electromagnetic flux generated does not enter the surrounding environment but follows the shape of the shielding assembly 96. In particular, after leaving the winding head W in a vertically upward direction, the field lines 116 are directed back, toward the lower part of the winding head W through the portion of the shielding assembly 96 covering the side 114 of the winding head W. In this way, a closed circle of magnetic field lines 116 is generated.

[0094] However, the inventors have observed that these field lines 116 extend through all the conductor parts present in the winding head W and therefore through all the coils 92, 94. Therefore, there is a strong electromagnetic interaction between the coils 92, 94, which should actually generate independent phases of the alternating current. This concerns in particular the central coil 94, which, since it is located between the outer coils 92, is subject to strong electromagnetic interactions in the region of its active part A.

[0095] The present invention seeks to overcome these problems by electromagnetically decoupling at least some of the coils 92, 94, for example, according to the following embodiments.

[0096] exist Figure 4 3 , a cross-section similar to that in FIG. 3 is shown. However, in this case, only the conductor portions of the outer coil 92 are positioned close to each other within the winding head W. In particular, they are positioned at a relatively small distance D1 from each other, which may be a few centimeters (e.g. less than 5 cm) or may even be zero. On the other hand, the conductor portion of the center coil 94 is located at a larger distance D2 from each conductor portion of the outer coil 92 within the winding head W. It should be noted that the distances D2 are of course different from each other but are marked in a similar manner to indicate that they all relate to the distance of the conductor portion of the center coil to the other conductor portions. Furthermore, the distances D1, D2 are perpendicular distances apparent from the coordinate system in FIG. 3 , which is useful for further Figures 4 to 6 Each of these is also valid.

[0097] Therefore, within the winding head W, the conductor portions of the outer coil 92 are closer to each other (distance D1) than the conductor portions of the center coil 94 (distance D2). Due to the air gap generated between the outer coil 92 and the center coil 94, the electromagnetic interaction between these coils 92, 94, in particular the undesirable influence of the outer coil 92 on the center coil 94, can be limited.

[0098] Thus, adjusting the distance between coils 92, 94 as shown in FIG. 3 represents an embodiment of the present invention, regardless of further features of shield assembly 96 discussed below.

[0099] Nonetheless, the depicted design of the shielding assembly 96 and specifically the portion of the magnetizable material 110 extending between the conductor portions in the winding head W provides a further advantageous embodiment.

[0100] In more detail, FIG3 shows that the shielding assembly 96 also has a portion of the side 114 covering the conductor portion within the winding head W. However, at a location between the conductor portion of the outer coil 92 and the conductor portion of the center coil 94, a protrusion of magnetizable material 110 is formed, which protrudes horizontally (i.e. along the transverse axis LA, see FIG3 ) and extends along the length of the winding head W (i.e. along the longitudinal axis LO, see FIG3 ). Thus, the protrusion of magnetizable material 110 extends into the air gap formed by the increased distance D2 between the outer and center coils 92, 94. When viewed along the vertical axis Z, the protruding magnetizable material 110 is therefore located between the conductor portions of the outer coil 92 and the center coil 94.

[0101] From below Figure 5 It will be apparent that providing corresponding protection for the magnetizable material 110 represents an embodiment of the present invention. By shielding these coils 92, 94 from each other within the winding head W, this feature can help limit electromagnetic interactions, particularly between the outer coil 92 and the center coil 94. Specifically, as described below with respect to Figure 4 As discussed, it helps to focus the magnetic field lines 116 of each of the outer coil 92 and the center coil 94 to a location close to the respective coil 92, 94. However, relative to the center coil 94, this may be Figure 4 This is achieved to a lesser extent than the embodiment of because the shielding assembly 96 does not cover the sides and bottom of the center coil 94.

[0102] Back to Figure 4, it can be seen that the shielding assembly 96 also covers the side 114 of the center coil 94 and includes another horizontal protrusion 120 of magnetizable material 110 extending parallel to the horizontal protrusion between the coils 92, 94. Therefore, the laterally inclined portion of the shielding assembly 96 or generally the portion of the shielding assembly 96 shielding (or surrounding) the winding head W has an E-shaped cross-section. Depending on the specific configuration, the branches of the E-shaped cross-section can have different lengths. For example, in Figure 4 , the upper branch is longer than the central branch and the lower branch formed by the corresponding protrusions of the magnetizable material 110 .

[0103] Each of the sides 114 of the outer coil 92 and the center coil 94 within the winding W is therefore partially surrounded by the shielding assembly 96, and more specifically, surrounded on three sides. This helps to concentrate the electromagnetic field generated by these coils 92, 94 close thereto. More precisely, as Figure 4 As shown, most of the magnetic field lines 116 can be guided by the shielding assembly 96, in particular with the help of the horizontal protrusions between the conductor sections, so as to produce a closed circle of corresponding field lines 116. In particular, it is possible to avoid that most of the field lines 116 of the outer coil 92 extend through the central coil 94, thereby limiting the electromagnetic interaction between these coils 92, 94.

[0104] Another embodiment of the present invention is Figure 6 In this case, the conductor portions within the winding head W are not spaced apart vertically but rather are spaced apart horizontally, more precisely, along the transverse axis LA (i.e., in the plane in which the active portions of the coils 92, 94 are formed). Specifically, the conductor portions of the center coil 94 are spaced apart from the conductor portions of the outer coils 92 along the transverse axis LA. Figure 6 3 . This distance particularly relates to the side faces 114 of the conductor sections or, in other words, is measured between the side faces 114. On the other hand, the vertical distances between the conductor sections can be regular, much like the equidistant spacing according to FIG. 3 . This particularly limits the vertical dimensions of the winding head W. However, the vertical distances can also be based on Figure 4 and Figure 5 The implementation scheme is configured to achieve particularly strong electromagnetic decoupling between the inner and outer parts of the winding head W and the center coils 92 and 94.

[0105] It should be noted that the horizontal / lateral distance between the conductor portions of the outer coil 92 is Figure 6 Therefore, the corresponding first distance D1 between these conductor parts is not Figure 6In addition, the longitudinal / lateral second distance D2 between the center coil and the outer coils 94, 92 is equal with respect to the two outer coils 92. In the wording of the present claim, the second distance D2 from the center coil 94 to each additional conductor portion of the outer coil 92 is equal to each other.

[0106] On the other hand, the configuration of the shielding assembly 96 is similar to the example of FIG. 3 . This also means that the magnetic field lines 116 are guided in a similar manner through all conductor sections within the winding head W. However, due to the distance D2, the (horizontal) length of the field lines 116 is increased. This means that the magnetic flux is weakened, especially in the air gap area formed by the horizontal distance D2. Likewise, this leads to limiting the electromagnetic interaction between the coils 92, 94, in particular limiting the influence of the outer coil 92 on the center coil 94.

[0107] exist Figure 7 In the Figure 6 90 without the shielding assembly 96. Likewise, the horizontal displacement of the central coil 94 relative to the outer coils 92 can be seen. It should be noted that the term "outer" relates to the position of the coils 92 along the longitudinal axis LO. As is evident from the depicted symmetry axis S, the lateral dimensions of the central coil 94 are thus reduced compared to the outer coils 92. However, this has no significant effect on the characteristics of the coils 92, 94 when the actual relevant dimensions are taken into account (e.g. the dimensions along the longitudinal axis are much larger than shown). Therefore, when exposed to an electromagnetic field, a considerable current is still induced in the coils 92, 94.

Claims

1. A conductor arrangement for inductive power transmission, The conductor arrangement comprises at least three coils which are arranged along a longitudinal axis and are formed by at least one conductor, The conductor arrangement comprises at least two winding heads which are arranged opposite one another along a transverse axis perpendicular to the longitudinal axis and in which the conductor sections of each of the coils extend along one another and along the longitudinal axis, In at least one of the two winding heads and at a position where the at least three coils extend side by side with each other, the conductor portions of a first coil and a second coil of the at least three coils extending along the longitudinal axis are arranged at a first distance from each other in a first direction perpendicular to the longitudinal axis and the transverse axis, the first distance being equal to or greater than zero, and the conductor portion of a third coil of the at least three coils extending along the longitudinal axis is arranged at a second distance from the conductor portions of the first coil and the second coil in a second direction perpendicular to the longitudinal axis and the transverse axis, the second distance being greater than the first distance. 2 . The conductor arrangement of claim 1 , the third coil being arranged at least partially between the first coil and the second coil when viewed along the longitudinal axis.

3. The conductor arrangement of claim 1, the first distance and the second distance extending along an axis parallel to a plane in which at least one of the coils is formed. The conductor arrangement of claim 1 , wherein the first distance and the second distance are horizontal distances. 5 . The conductor arrangement according to claim 3 , the third coil having a smaller transverse dimension than the first and second coils, the transverse dimension extending between the winding heads.

6. The conductor arrangement of claim 1, the first distance and the second distance extending along an axis that is not parallel to a plane in which at least one of the coils is formed. The conductor arrangement of claim 1 , wherein the first distance and the second distance are perpendicular distances.

8. The conductor arrangement of claim 6, wherein within each winding head, a magnetizable material is arranged between the conductor portion of the third coil and a conductor portion of one of the first and second coils.

9. A conductor arrangement according to claim 8, magnetisable material being arranged between respective conductor portions when viewed along an axis which is not parallel to a plane in which at least one of the coils is formed.

10. The conductor arrangement of claim 8, the magnetizable material being formed as a protrusion extending at least partially parallel to a plane in which at least one of the coils is formed.

11. A conductor arrangement according to claim 8, the magnetisable material being part of a shielding assembly extending along each winding head.

12. The conductor arrangement of claim 1, wherein within each winding head, the magnetizable material is located opposite a side of the conductor portion of the third coil, the side facing away from the first coil and the second coil.

13. An inductive power transmission device, comprising a primary side configured to generate an electromagnetic field and a secondary side configured to receive the electromagnetic field, thereby generating magnetic induction on the secondary side, At least one of the primary side and the secondary side comprises a conductor arrangement according to claim 1 .

14. The inductive power transfer device of claim 13, the secondary side being arranged on a land vehicle and the primary side being arranged around the land vehicle.

15. A conductor arrangement for inductive power transmission, The conductor arrangement comprises at least three coils which are arranged along a longitudinal axis and are formed by at least one conductor, the conductor arrangement comprising at least two winding heads arranged opposite to each other and wherein the conductor sections of each of the at least three coils extend along each other and along the longitudinal axis, wherein each of the winding heads comprises a side surface extending along the conductor section; The conductor arrangement further comprises a shielding component made of a magnetizable material, the shielding component covering a side surface of at least one of the at least two winding heads and comprising a protrusion extending inwardly relative to the conductor arrangement so as to be located between and extend along adjacent conductor portions, so that the magnetizable material separates at least one conductor portion from at least two conductor portions within the winding head. 16 . The conductor arrangement according to claim 15 , wherein the at least one winding head is a region where the extension direction of each of the at least three coils is reversed.

17. A method of providing a conductor arrangement for inductive power transfer, comprising forming at least three coils to form a conductor arrangement and arranging the coils along a longitudinal axis, and so that at least two winding heads are formed which are arranged opposite to each other along a transverse axis perpendicular to the longitudinal axis, and in which the conductor parts of each of the at least three coils extend along each other and along the longitudinal axis, and Such that, within at least one of the two winding heads and at a position where the at least three coils extend side by side with each other, the conductor portions of the first coil and the second coil of the at least three coils extending along the longitudinal axis are arranged at a first distance from each other in a first direction perpendicular to the longitudinal axis and the transverse axis, the first distance being equal to or greater than zero, and the conductor portion of the third coil of the at least three coils extending along the longitudinal axis is arranged at a second distance from the conductor portions of the first coil and the second coil in a second direction perpendicular to the longitudinal axis and the transverse axis, the second distance being greater than the first distance.

18. A method of providing a conductor arrangement for inductive power transfer, comprising at least three coils forming a conductor arrangement such that the coils are arranged along a longitudinal axis, so that at least two winding heads are formed which are arranged opposite to each other and in which the conductor portions of each of the at least three coils extend along each other and along the longitudinal axis, wherein each of the winding heads comprises a side surface extending along the conductor portion; and A shielding assembly made of a magnetizable material is provided, the shielding assembly covering a side of at least one of the at least two winding heads and comprising a protrusion extending inwardly relative to the conductor arrangement so as to be located between and extend along adjacent conductor portions, so that the magnetizable material separates at least one conductor portion from at least two conductor portions within the winding head. 19 . The method according to claim 18 , wherein the at least one winding head is a region where an extension direction of each of the at least three coils is reversed.

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