WO2023063889A2

WO2023063889A2 - Magnetic coupling structure

Info

Publication number: WO2023063889A2
Application number: PCT/SG2022/050731
Authority: WO
Inventors: Yiming Zhang; Xin Li; Shuxin CHEN; Yi Tang
Original assignee: Nanyang Technological University
Priority date: 2021-10-15
Filing date: 2022-10-13
Publication date: 2023-04-20
Also published as: WO2023063889A3

Abstract

According to embodiments of the present invention, a magnetic coupling structure is provided. The magnetic coupling structure includes a first coupler; a second coupler arranged opposite the first coupler; and at least one non-planar magnetic pillar having a longitudinal axis. One of the first coupler and the second coupler is stationary, and another of the first coupler and the second coupler is movable along the at least one non-planar magnetic pillar to form and adjust a gap between the first coupler and the second coupler along the longitudinal axis.

Description

MAGNETIC COUPLING STRUCTURE

Cross-Reference To Related Application

[0001] This application claims the benefit of priority of Singapore patent application No. 10202111489P, filed 15 October 2021, the content of it being hereby incorporated by reference in its entirety for all purposes.

Technical Field

[0002] Various embodiments relate to a magnetic coupling structure for wireless power transfer applications.

Background

[0003] Wireless power transfer (WPT) is an emerging technology that enables a cord to be cut off between a source and a load. Without direct metal contact, the issues of sparks and aging may be significantly minimized or eliminated. The advantages of WPT may include safety, automation, unattendance, and convenience. Due to these advantages, WPT technology may be applied in various applications, such as implantable medical devices, consumer electronics (cellphones and tablets), electric vehicles (EVs), railway transit, and electric ships.

[0004] Presently, the most popular and mature WPT technology is inductive power transfer based on magnetic induction. Magnetic couplers, namely the coupled coils, are employed to transfer power from a source to a load. Magnetic couplers, as the essential part in a WPT system, play an essential role in the performance of the WPT system.

[0005] Magnetic couplers mainly include two parts: a static coupler and a movable coupler. Each coupler typically includes windings and magnetic cores. Windings are generally copper based, such as Litz wires or copper tracks on printed circuit boards, in which an alternating current (AC) flows through. Magnetic cores, mainly and typically composed of ferrite, guide the magnetic flux distribution and help achieve a strong coupling. The magnetic cores are also helpful to deal with electromagnetic interference and electromagnetic compatibility.

[0006] In high-power WPT applications, such as wireless charging for ships with the power level up to several hundreds of kilowatts or even megawatts, high power density, light weight, and low cost are the major design requirements, especially on the movable part of the wireless charging system. Theoretical analysis shows that the coupling coefficient of the magnetic couplers and the self-inductances are crucial in determining the power level and the power density of a WPT system. The larger the coupling coefficient, the higher the power level and power density, resulting in light weight and low cost. In the current existing magnetic coupler structures, planar magnetic cores are most widely used. For example, a prior publication discloses a circular coupler which uses an T shape ferrite core, which is generally flat ferrite plate. However, the leakage flux of such planar magnetic core is usually large, restricting the improvement of the coupling coefficient. Furthermore, the planar magnetic cores tend to dramatically increase the weight and cost of the WPT system, especially those of the movable coupler.

[0007] Thus, there is a need for novel magnetic coupler structures that address at least the problems mentioned above.

Summary

[0008] According to an embodiment, a magnetic coupling structure is provided. The magnetic coupling structure may include a first coupler; a second coupler arranged opposite the first coupler; and at least one non-planar magnetic pillar having a longitudinal axis. One of the first coupler and the second coupler may be stationary, and another of the first coupler and the second coupler may be movable along the at least one non-planar magnetic pillar to form and adjust a gap between the first coupler and the second coupler along the longitudinal axis. Brief Description of the Drawings

[0009] In the drawings, like reference characters generally refer to like parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the invention are described with reference to the following drawings, in which:

[0010] FIG. 1A shows a schematic view of a magnetic coupling structure, according to various embodiments.

[0011] FIG. IB shows a simplified schematic view of the magnetic coupling structure of FIG. 1A where a second coupler is stationary and a first coupler is movable, according to various embodiments.

[0012] FIG. 1C shows a simplified schematic view of the magnetic coupling structure of FIG. 1A where a first coupler is stationary and a second coupler is movable, according to various embodiments.

[0013] FIG. ID shows a schematic partial side view of a first coupler being movable, as in FIG. IB, and receiving a portion of a non-planar pillar, according to various embodiments. [0014] FIG. IE shows a schematic partial side view of a part of a second coupler being stationary, as in FIG. IB, and receiving another portion of a non-planar pillar, according to various embodiments.

[0015] FIG. IF shows a schematic side view of a magnetic coupling structure having two further bordering pillars arranged adjacent to a first coupler and a second coupler, according to various embodiments.

[0016] FIG. 2A shows a schematic perspective view of an exemplary conventional magnetic coupler structure.

[0017] FIG. 2B shows an exploded view of FIG. 2A.

[0018] FIG. 2C shows a schematic perspective view of a magnetic coupler structure, according to one embodiment.

[0019] FIG. 2D shows an exploded view of FIG. 2C.

[0020] FIG. 3A shows a schematic perspective view of a magnetic coupler structure with circular coils, according to one embodiment. [0021] FIG. 3B shows an exploded view of FIG. 3A.

[0022] FIG. 4A shows a schematic perspective view of a magnetic coupler structure with bipolar coils, according to one embodiment.

[0023] FIG. 4B shows an exploded view of FIG. 4A.

[0024] FIGS. 4C to 4E show schematic exploded perspective view of different magnetic coupler structures with bipolar coils, according to various examples.

[0025] FIG. 5A shows a schematic perspective view of a magnetic coupler structure with circular coils and surrounding magnetic pillars, according to one embodiment.

[0026] FIG. 5B shows an exploded view of FIG. 5A.

Detailed Description

[0027] The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the invention. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

[0028] Embodiments described in the context of one of the methods or devices are analogously valid for the other methods or devices. Similarly, embodiments described in the context of a method are analogously valid for a device, and vice versa.

[0029] Features that are described in the context of an embodiment may correspondingly be applicable to the same or similar features in the other embodiments. Features that are described in the context of an embodiment may correspondingly be applicable to the other embodiments, even if not explicitly described in these other embodiments. Furthermore, additions and/or combinations and/or alternatives as described for a feature in the context of an embodiment may correspondingly be applicable to the same or similar feature in the other embodiments.

[0030] In the context of various embodiments, the articles “a”, “an” and “the” as used with regard to a feature or element include a reference to one or more of the features or elements. [0031] In the context of various embodiments, the phrase “substantially” may include “exactly” and a reasonable variance.

[0032] In the context of various embodiments, the term “about” as applied to a numeric value encompasses the exact value and a reasonable variance.

[0033] As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

[0034] As used herein, the expression “configured to” may mean “constructed to” or “arranged to”.

[0035] Various embodiments provide magnetic couplers with magnetic pillars for flux guidance, mechanical positioning, and support in high-power wireless charging applications.

[0036] FIG. 1A shows a schematic view of a magnetic coupling structure 100 in accordance with various embodiments. The magnetic coupling structure 100 includes a first coupler 102; a second coupler 106 arranged opposite the first coupler 102; and at least one non-planar magnetic pillar 104 having a longitudinal axis 101 (FIGS. ID to IF). One of the first coupler 102 and the second coupler 106 may be stationary, and another of the first coupler 102 and the second coupler 106 may be movable along or alongside the at least one non-planar magnetic pillar 104 to form and adjust a gap 103 (FIG. IF) between the first coupler 102 and the second coupler 108 along the longitudinal axis 101. The first coupler 102 and the second coupler 106 may be arranged with respect to the at least one non-planar magnetic pillar 104, as respectively denoted by lines 112, 114.

[0037] FIG. IB shows a simplified schematic view of the magnetic coupling structure 100 of FIG. 1A where the first coupler 102 is movable, as denoted by arrow 109a, and the second coupler 106 is stationary, according to various embodiments. In this case, the first coupler 102 may be referred to as a movable coupler and the second coupler 106 may be referred to as a static coupler. FIG. 1C shows a simplified schematic view of the magnetic coupling structure 100 of FIG. 1A where the second coupler 106 is movable, as denoted by arrow 109b, and the first coupler 102 is stationary, according to other embodiments. In this other case, the first coupler 102 may be referred to as a static coupler and the second coupler 106 may be referred to as a movable coupler. [0038] Taking the configuration provided by FIG. IB as an example, FIG. ID shows a schematic partial side view of the first coupler 102, being the movable coupler, receiving a portion of the non -planar magnetic pillar 104, while FIG. IE shows a schematic partial side view of a part of the second coupler 106, being the static coupler, receiving another portion of the non-planar magnetic pillar 104, according to various embodiments.

[0039] FIG. IF shows a schematic side view of a magnetic coupling structure 100’ having two bordering pillars 105 arranged adjacent to the first coupler 102 and the second coupler 106, according to some embodiments. As shown in FIGS. ID to IF, the magnetic coupling structure 100, 100’ may include the at least one non-planar magnetic pillar 104 which may be an elongate member.

[0040] In other words, taking the configuration provided by FIG. IB as an example with reference to FIGS. ID to IF, the second coupler 106 is non-movable and may be positioned at or near a base or proximal end 104a (FIG. IF) of the non-planar magnetic pillar 104. This may provide the non-planar magnetic pillar 104 arranged with its longitudinal axis 101 extending away (e.g. upwardly) from the second coupler 106. The first coupler 102 may be configured to move or slide upwardly towards or downwardly away from a top or distal end 104b (FIG. IF) of the non-planar magnetic pillar 104 along the longitudinal axis

101. On the other hand, taking the configuration provided by FIG. 1C as an alternative example but not shown in any other figures, the first coupler 102 may be non-movable and may be positioned at or near a base or proximal end 104a (FIG. IF) of the non-planar magnetic pillar 104. This may provide the non-planar magnetic pillar 104 arranged with its longitudinal axis 101 extending away (e.g. upwardly) from the non-movable first coupler

102. Here, the second coupler 106 may be configured to move or slide upwardly towards or downwardly away from a top or distal end 104b (FIG. IF) of the non-planar magnetic pillar 104 along the longitudinal axis 101. In both examples described above, the gap 103 between the first coupler 102 and the second coupler 106 may be formed and adjusted to various gap sizes to cater for different applications.

[0041] Magnetic coupler structures, for example, the magnetic coupling structure 100, 100’ of FIGS. 1A and IF, are suitable for both low-power and high-power applications to achieve light weight and low cost of the couplers in a wireless charging system. High- power applications may further benefit from high power density in the wireless charging system.

[0042] Further various embodiments of the magnetic coupling structure 100, 100’ will be described below in general without taking any specific reference to the configurations of FIGS. IB and 1C, unless otherwise specified.

[0043] In various embodiments, the first coupler 102 may be made up of only (solely) a substructure-free winding 107. Specifically, the first coupler 102 is the substructure-free winding 107 alone, and free from or in absence of any overlying or adjacent magnetic substructure (e.g. ferrite).

[0044] The first coupler 102, being the substructure-free winding 107, may be shaped to provide a first surface 102b arrangeable to face towards the second coupler 106; a second surface 102a opposite to the first surface 102b, the second surface 102a arrangeable to face away from the second coupler 106; an interior periphery 102c extending between the first surface 102b and the second surface 102a, the interior periphery 102c defining an aperture 116 configured to receive a portion of the at least one non -planar magnetic pillar 104 along the longitudinal axis 101; and an exterior periphery 102d being opposite to the interior periphery 102c and extending between the first surface 102b and the second surface 102a. In context of various embodiments, the expression “surface” may be seen as a surface with one or more openings due to the coiling of the substructure-free winding 107. In one example, the surface may be annular. The expressions “internal periphery” and “exterior periphery” may be referred to as inner wall and outer wall of the first coupler 102, respectively. It should be appreciated that the aperture 116 may be shaped and dimensioned in a manner that allows the portion of the at least one non -planar magnetic pillar 104 to be received therein.

[0045] In various embodiments, the second coupler 106 may include a winding 108 being shaped to provide a first plane 108b arrangeable to face towards the first surface 102b of the first coupler 102; a second plane 108a opposite to the first plane 108b, the second plane 108a arrangeable to face away from the first coupler 102; an interior wall surface 108c extending between the first plane 108b and the second plane 108a, the interior wall surface 108c defining a receiving portion 118 configured to receive another portion of the at least one non-planar magnetic pillar 104 along the longitudinal axis 101; and an exterior wall surface 108d being opposite to the interior wall surface 108c and extending between the first plane 108b and the second plane 108a. In context of various embodiments, the expression “plane” may be seen as a plane or surface with one or more openings due to the coiling of the winding 108. In one example, the plane may be annular. The expressions “internal wall surface” and “exterior wall surface” may be referred to as inner wall and outer wall of the winding 108, respectively. FIGS. IE and IF show the receiving portion 118 extending along the entire height of the interior wall surface 108c, thereby allowing the other portion of the at least one non-planar magnetic pillar 104 (e.g. a proximal end 104a of the at least one non-planar magnetic pillar 104 in FIG. IF) to be flushed with the second plane 108a. However, it should be appreciated that in some other examples, the receiving portion 118 may be extending along a part of the height of the interior wall surface 108c, and in such case, the proximal end 104a of the at least one non-planar magnetic pillar 104 may not flushed with the second plane 108a (not shown in figures).

[0046] Optionally, the second coupler 106 may further include a magnetic substructure 110 (FIGS. 1A and IF) adjacent to the winding 108. For example, the magnetic substructure 110 may be adjacent to or overlying the winding 108. The second plane 108a of the winding 108 may be arrangeable to face towards the magnetic substructure 110. In some examples, the magnetic substructure 110 and the at least one non-planar magnetic pillar 104 may form an integral unit.

[0047] In other embodiments, the winding 108 may be free from a magnetic substructure such that the second coupler 106 is made up of only the winding 108.

[0048] In view of the various embodiments described above, it may be summarized that various embodiments may provide the following: the first coupler 102 being made up of only the substructure-free winding 107 and the second coupler 106 being up of only the winding 108, thereby rendering both the first coupler 102 and the second coupler 106 free from magnetic substructure(s); or the first coupler 102 being made up of only the substructure-free winding 107 and the second coupler 106 including both the winding 108 and the magnetic substructure 110, thereby rendering the magnetic coupling structure 100, 100’ asymmetrical. [0049] For example, eliminating the need for a magnetic substructure on the first coupler 102 (or even on the second coupler 106) may address the challenges encountered by conventional magnetic couplers (e.g. 200’ of FIGS 2A and 2B) that are symmetrical, with both the winding 202”, 208 and the magnetic substructure 210a, 210b on each of the static magnetic coupler 206 and the movable magnetic coupler 202’. The asymmetrical magnetic coupling structure 100, 100’ may experience improved power density of at least the first coupler 102, and the cost, weight and size of at least the first coupler 102 may be significantly reduced as compared to those of the conventional magnetic couplers.

[0050] The at least one non -planar magnetic pillar 104 may include a proximal end 104a; a distal end 104b opposite to the proximal end 104a; and a wall 104c extending along the longitudinal axis 101 between the proximal end 104a and the distal end 104b. The proximal end 104a may be configured to be received by either the receiving portion 118 of the winding 108 when the second coupler 106 is stationary and the first coupler 102 is movable, or the aperture 116 of the substructure-free winding 107 (or the first coupler 102) when the first coupler 102 is stationary and the second coupler 106 is movable. In other words, in the case where the second coupler 106 is stationary, the second coupler 106 may be arranged towards the proximal end 104a of the at least one non-planar magnetic pillar 104. On the other hand, in the case where the first coupler 102 is stationary, the first coupler 102 may be arranged towards the proximal end 104a of the at least one non-planar magnetic pillar 104. The other of the first coupler 102 and the second coupler 106 may be movable or moved along the wall 104c towards or away from the distal end 104b of the at least one non-planar magnetic pillar 104 (or may be movable away or towards the proximal end 104a of the at least one non-planar magnetic pillar 104).

[0051] In some embodiments, the at least one non-planar magnetic pillar 104 may be disposed at the receiving portion 118 of the winding 108 when the second coupler 106 is stationary and the first coupler 102 is movable, and the at least one non-planar magnetic pillar 104 may extend at least partially through the aperture 116 of the substructure-free winding 107 such that the winding 108 and the substructure-free winding 107 surround at least part of the wall 104c of the at least one non-planar magnetic pillar 104. In other words, both the winding 108 and the substructure-free winding 107 coil around and encircle the entire circumferential periphery of the wall 104c of the at least one non-planar magnetic pillar 104. In one example, the at least one non-planar magnetic pillar 104 may be observed as protruding through the receiving portion 118 of the winding 108 and the aperture 116 of the substructure-free winding 107. The receiving portion 118 and the aperture 116 may be through-holes for receiving the at least one non-planar magnetic pillar 104. In another example, the receiving portion 118 and the aperture 116 may be blinded in that each of the receiving portion 118 and the aperture 116 may have one closed end, thus forming a recess or the like to receive parts of the at least one non-planar magnetic pillar 104. Each of the receiving portion 118 and the aperture 116 may be blinded by filling a part of thereof with a filling material. For example, the filling material may be non-magnetic or non-metallic such as plastic.

[0052] In some examples, the receiving portion 118 may be disposed at a center or midpoint of the winding 108, and effectively the second coupler 106, while the aperture 116 may be disposed at a center or midpoint of the first coupler 102. In other examples (not shown in FIGS. 1A to IF), the receiving portion 118 may be disposed at an off-center position of the winding 108, and effectively the second coupler 106, while the aperture 116 may be disposed at an off-center of the first coupler 102. The at least one non-planar magnetic pillar 104 may have a wall height larger than or substantially the same as the combined thicknesses of the winding 108 and the first coupler 102. In a different example, the at least one non-planar magnetic pillar 104 may have a wall height smaller than the combined thicknesses of the winding 108 and the first coupler 102, but still sufficient to allow at least part of the winding 108 and the substructure-free winding 107 to encircle the at least one non-planar magnetic pillar 104.

[0053] In other embodiments, the substructure-free winding 107 may be further shaped to provide a further or additional interior periphery (that may be described in similar context to the interior periphery 102c) extending between the first surface 102b and the second surface 102a, the further interior periphery defining a further or additional aperture (that may be described in similar context to the aperture 116) configured to receive a further portion of the at least one non-planar magnetic pillar 104 along the longitudinal axis 101. The winding 108 may be further shaped to provide a further or additional interior wall surface (that may be described in similar context to the interior wall surface 108c) extending between the first plane 108b and the second plane 108a, the further interior wall surface defining a further or additional receiving portion (that may be described in similar context to the receiving portion 118) configured to receive another further portion of the at least one non-planar magnetic pillar 104 along the longitudinal axis 101. Each of the at least one non-planar magnetic pillar 104 (here being two or more non-planar magnetic pillar 104) may be disposed correspondingly at the receiving portion 118 and the further receiving portion of the winding 108 when the second coupler 106 is stationary and the first coupler 102 is movable, and each the at least one non-planar magnetic pillar 104 extends correspondingly and at least partially through the aperture 116 and the further aperture of the substructure-free winding 107 such that the winding 108 and the substructure-free winding 107 surround at least part of the wall 104c of each of the at least one non-planar magnetic pillar 104. With respect to these other embodiments, an example may be provided as seen in a magnetic coupler structure 400 of FIGS. 4 A and 4B with two non-planar magnetic pillars 404a, 404b, where the substructure-free winding may refer to the movable coupler 402 with an aperture 416a and a further aperture 416b, and the winding 408 includes a receiving portion 418a at which one of the two non-planar magnetic pillars 404a is disposed and a further receiving portion 418b at which the other one of the two non-planar magnetic pillars 404b is disposed. More details of the magnetic coupler structure 400 of FIGS. 4A and 4B will be described herein later on.

[0054] In alternative embodiments, the at least one non-planar magnetic pillar 104 may be disposed at the aperture 116 of the substructure-free winding 107 when the first coupler 102 is stationary and the second coupler 106 is movable, and the at least one non-planar magnetic pillar 104 extends through the receiving portion 118 of the winding 108 such that the winding 108 and the substructure-free winding 107 surround at least part of the wall 104c of the at least one non-planar magnetic pillar 104.

[0055] In yet other alternative embodiments, when the first coupler 102 is stationary and the second coupler 106 is movable, the substructure-free winding 107 may be further shaped to provide a further or additional interior periphery (that may be described in similar context to the interior periphery 102c) extending between the first surface 102b and the second surface 102a, the further interior periphery defining a further or additional aperture (that may be described in similar context to the aperture 116) configured to receive a further portion of the at least one non-planar magnetic pillar 104 along the longitudinal axis 101. The winding 108 may be further shaped to provide a further or additional interior wall surface (that may be described in similar context to the interior wall surface 108c) extending between the first plane 108b and the second plane 108a, the further interior wall surface defining a further or additional receiving portion (that may be described in similar context to the receiving portion 118) configured to receive another further portion of the at least one non-planar magnetic pillar 104 along the longitudinal axis 101. Each of the at least one non-planar magnetic pillar 104 (here being two or more non-planar magnetic pillar 104) may be disposed correspondingly at the aperture 116 and the further aperture of the substructure-free winding 107 when the first coupler 102 is stationary and the second coupler 106 is movable, and each the at least one non-planar magnetic pillar 104 extends correspondingly and at least partially through the receiving portion 118 and the further receiving portion of the winding 108 such that the winding 108 and the substructure-free winding 107 surround at least part of the wall 104c of each of the at least one non-planar magnetic pillar 104.

[0056] In a specific example, the at least one non-planar magnetic pillar 104 may refer to at least one bordering magnetic pillar 105 (FIG. IF). In such a case (not shown in the figures), the magnetic coupling structure 100 only include bordering magnetic pillar(s), absent of any central magnetic pillar(s).

[0057] Various embodiments may provide the at least one non-planar magnetic pillar 104 having a horizontal cross-section substantially perpendicular to the longitudinal axis 101, the horizontal cross-section being polygonal, circular, or elliptical in shape. In various embodiments, the wall 104c of the at least one non-planar magnetic pillar 104 may have non-uniform sections. This means that the wall 104c may have different horizontal crosssections along its height. For example, the wall 104c may be tapered or may have stepped sections (not shown in the figures). In other embodiments, the wall may be uniform where the same horizontal cross-sections are provided throughout its substantially entire height, for example as seen in FIG. IF. Each of the receiving portion 118 of the winding 108 and the aperture 116 of the first coupler 102 may have a width that is equal or larger than the largest size of the horizontal cross-section of the at least one non-planar magnetic pillar 104 or a relevant portion thereof. In one example, the horizontal cross-section with the largest size may be found along a portion of the at least one non-planar magnetic pillar 104 that is received by the second coupler 106. In another example, the horizontal cross-section with the largest size may be found along a portion of the at least one non-planar magnetic pillar 104 that is received by the first coupler 102.

[0058] In various embodiments, each of the first surface 102b and the second surface 102a of the first coupler 102 may follow a shape of a polygon, circle, or ellipse. Each of the first plane 108b and the second plane 108a of the winding 108 may follow a shape of a polygon, circle, or ellipse.

[0059] In other examples, the surfaces and planes mentioned above may be of other regular or irregular shapes that are not specified herein.

[0060] In various embodiments, the substructure-free winding 107 may be different in size (smaller or larger) as compared to the winding 108. For example, the first surface 102b and the second surface 102a of the substructure-free winding 107 may be smaller as compared to the first plane 108b and the second plane 108a of the winding 108.

[0061] In another examples, the substructure -free winding 107 may have a thickness different from that of the winding 108. The thickness may be interchangeably referred to as the height that is measured along a plane parallel to the longitudinal axis 101 of the non- planar magnetic pillar 104 and perpendicular to the first surface 102b and the second surface 102a of the substructure-free winding 107, or to first plane 108b and the second plane 108a of the winding 108. In other words, the thickness of the substructure-free winding 107 may be the height of the interior periphery 102c and/or the exterior periphery 102d of the first coupler 102. The thickness of the winding 108 may be the height of the interior wall surface 108c and/or the exterior wall surface 108d of the winding 108. For example, in one embodiment, the thickness of the substructure-free winding 107 may be half that of the winding 108.

[0062] In some embodiments, each of the first plane 108b and the second plane 108a of the winding 108 has a size and shape that may be substantially similar to those of the (optional) magnetic substructure 110. Effectively, the winding 108 being adjacent to the magnetic substructure 110 may cover over the entire magnetic substructure 110.

[0063] In various embodiments, the magnetic substructure 110 of the second coupler 106 may include ferrite. The at least one non-planar magnetic pillar 104 may include ferrite. In alternative examples, instead of ferrite, other magnetic or ferrimagnetic or crystalline or amorphous materials may be used.

[0064] Taking reference to FIG. IF, the magnetic coupling structure 100’ may further include at least one bordering magnetic pillar 105. The at least one bordering magnetic pillar 105 may include a first end region 105a; a second end region 105b opposite to the first end region 105a; and a bordering wall 105c extending between the first end region 105a and the second end region 105b. The first region 105a may be arranged toward the second coupler 106 when the second coupler 106 is stationary and the first coupler 102 is movable, with a part 105c’ of the bordering wall 105c adjacent to at least a part of the exterior wall surface 108d of the winding 108. With this, the second end region 105b may be arranged away from the second coupler 106, with another part 105c” of the bordering wall 105c adjacent to at least a part of the exterior periphery 102d of the first coupler 102, thereby allowing the first coupler 102 to move alongside the bordering wall 105c toward or from the second end region 105b. The exterior wall surface 108d of the winding 108 refers to an outermost circumference of the second coupler 106 that is maximally extended in an outwardly and radially manner from the interior wall surface 108c of the winding 108. The exterior periphery 102d of the first coupler 102 may be movable or moved alongside the bordering wall 105c toward or away from the second end region 105b. The exterior periphery 102d of the first coupler 102 refers to an outermost circumference of the first coupler 102 that is maximally extended in an outwardly and radially manner from the interior periphery 102c of the first coupler 102.

[0065] Not shown in the figures, an alternative embodiment may provide the magnetic coupling structure 100 further including at least one bordering magnetic pillar 105 including a first end region 105 a; a second end region 105b opposite to the first end region 105a; and a bordering wall 105c extending between the first end region 105a and the second end region 105b, wherein the first region 105a may be arranged toward the first coupler 102 when the first coupler 102 is stationary and the second coupler 106 is movable, with a part 105c’ of the bordering wall 105c adjacent to at least a part of the exterior periphery 102d of the first coupler 102. With this, the second end region 105b may be arranged away from the first coupler 102, with another part 105c” of the bordering wall 105c adjacent to at least a part of the exterior wall surface 108d of the winding 108, thereby allowing the second coupler 106 to move alongside the bordering wall 105c toward or from the second end region 105b.

[0066] In various embodiments, the at least one bordering magnetic pillar 105 may be free from being encircled by the winding 108 and the substructure-free winding 107.

[0067] The at least one bordering magnetic pillar 105 may include a plurality of bordering magnetic pillars arranged spaced apart from one another around at least part of the exterior wall surface 108d of the winding 108 and at least part of the exterior periphery 102d of the first coupler 102. In other words, the plurality of bordering magnetic pillars may form a continual boundary enclosing the second coupler 106 and the first coupler 102.

[0068] Examples of the magnetic coupling structure (interchangeably referred to as magnetic coupler structure) will be described in more detail below.

[0069] FIG. 2C shows a perspective schematic view of an exemplary magnetic coupler structure 200 in accordance with one embodiment, while FIG. 2D shows an exploded view of FIG. 2C. For the ease of discussion, this exemplary magnetic coupler structure 200 takes on the configuration of FIG. IB.

[0070] As shown in FIGS. 2C and 2D, the magnetic coupler structure 200 is based on an asymmetrical magnetic coupler design generated by eliminating ferrite (e.g. 210b of FIGS. 2 A and 2B) on the movable coupler 202 (that may be described in similar context to the first coupler 102 of FIG. IB) to reduce cost and weight. As as result, the movable coupler 202 is solely or is only composed of the winding (which may be described in similar context to the substructure-free winding 107 being the first coupler 102 of FIG. IB). The magnetic coupler structure 200 may include the same or like elements or components as those of the magnetic coupling structure 100, 100’ of FIGS. 1A, IB, and ID to IF, and as such, the same end numerals are assigned and the like elements may be as described in the context of the magnetic coupling structure 100, 100’ of FIGS. 1A, IB and ID to IF, and therefore the corresponding descriptions with respect to the magnetic coupler structure 200 may be omitted herein.

[0071] The size of the winding (e.g. similar to the substructure-free winding 107) being the movable coupler 202 may also be reduced. More specifically, the winding size of the movable coupler 202 may be designed to be smaller than the winding size of the winding 208 of the static coupler 206 (that may be described in similar context to the second coupler 106 of FIG. IB), forming an asymmetrical winding design. The smaller size may be reflected on the smaller thickness (as shown in FIGS. 2C and 2D), or smaller length or width (not shown in the figures). Ferrite 204 (in the form of a non-planar magnetic pillar, e.g. 104 in FIGS. 1 A, IB, ID and IE) may be placed at the center (e.g. the receiving portion 118 in FIGS. 1A, IE and IF) of the static coupler 206 and extended to the center (e.g. the aperture 116 in FIGS. 1A, ID and IF) of the movable coupler 202 along a longitudinal axis

201 (which may be described in similar context to the longitudinal axis 101 of FIGS. ID to IF), so as to guide the magnetic flux to enhance the coupling, help mechanical positioning and provide support. The center of the static coupler 206 may be defined by the interior wall surface 208c (which may be described in similar context to the interior wall surface 108c in FIG. IE) of the winding 208. The center of the movable coupler 202 may be defined by the interior periphery 202c (which may be described in similar context to the interior periphery 102c in FIG. ID) of the movable coupler 202. The movable coupler

202 may be arranged towards a distal end 204b (which may be described in similar context to the distal end 104b of FIG. IF) of the ferrite 204. The static coupler 206 includes the winding 208 adjacent to or overlying the ferrite 210 (which may be described in similar context to the magnetic substructure 110 of FIGS. 1A and IF). As such, the plane 208a (which may be described in similar context to the second plane 108a in FIGS. IE and IF) of the winding 208 is arranged facing the ferrite 210. In this example, the plane 208a is of substantially the same size as the horizontal cross-sectional area of the ferrite 210, thereby allowing the exterior wall surface 208d (which may be described in similar context to the exterior wall surface 108d in FIG. IE) of the winding 208 to be aligned to the ferrite 210. [0072] The static coupler 206 and the movable coupler 202 may be arranged spaced apart with a gap 203 (which may be described in similar context to the gap 103 of FIG. IF) therebetween such that the surface 202b (which may be described in similar context to the first surface 102b in FIGS. ID and IF) of the movable coupler 202 and the plane 208b (which may be described in similar context to the first plane 108b in FIGS. IE and IF) of the winding 208 are facing each other. The movable coupler 202 may also provide another surface 202a (which may be described in similar context to the second surface 102a in FIGS. ID and IF) facing away from the static coupler 206, and an exterior periphery 202d (which may be described in similar context to the exterior periphery 102d in FIG. ID). In this example, the winding being the movable coupler 202 and the winding 208 of the static coupler 206 are square coils. The ferrite 204 may be a non-planar magnetic pillar in the shape of a rectangular prism or a square prism.

[0073] The magnetic coupler design is not restricted to the specific coupler types exemplified herein. In fact, the magnetic couplers may be of other shapes, such as circular, rectangular or bipolar. The magnetic pillar may also be of other types, such as rectangular, circular, and triangular.

[0074] The description to FIGS. 2C and 2D may be adapted correspondingly for the configuration of FIG. 1C where 206 may be movable and 202 may be stationary instead.

[0075] Further exemplary magnetic coupling structures 300, 400 are shown in FIG. 3A and FIG. 4A, respectively. The magnetic coupler structures 300, 400 may include the same or like elements or components as those of the magnetic coupling structure 100, 100’ of FIGS. 1A, IB and IF as well as the magnetic coupler structure 200 of FIGS. 2C and 2D, and as such, the same end numerals are assigned and the like elements may be as described in the context of the magnetic coupling structure 100, 100’ of FIGS. 1A, IB and IF as well as the magnetic coupler structure 200 of FIGS. 2C and 2D, and therefore the corresponding descriptions may be omitted herein for simpicity. The corresponding descriptions may include references to various parts of the movable coupler 302, the static coupler 306 and the ferrite 304.

[0076] FIG. 3A shows a perspective schematic view of another exemplary magnetic coupler structure 300 in accordance with one embodiment, while FIG. 3B shows an exploded view of FIG. 3A.

[0077] As seen in FIGS. 3A and 3B, the arrangements of the various parts of the magnetic coupler structure 300 may be similar to those of the magnetic coupler structure 200 of FIGS. 2C and 2D, while the shapes of the various parts of the magnetic coupler structure 300 may differ from those of the magnetic coupler structure 200 of FIGS. 2C and 2D. Thus, corresponding descriptions relating to the arrangements of the various parts of magnetic coupler structure 200 may be applicable here. The static coupler 306 and the movable coupler 302 may be arranged spaced apart with a gap 303 therebetween. In this example, the winding being the movable coupler 302 (that may be described in similar context to the substructure-free winding 107 being the first coupler 102 of FIG. IB) and the winding 308 of the static coupler 306 (that may be described in similar context to the second coupler 106 of FIG. IB) are circular coils. The ferrite 304 may be a non-planar magnetic pillar in the shape of a circular-based cylinder that may be placed in the center 318 (e.g. the receiving portion 118 in FIGS. 1A, IE, and IF) of the static coupler 306 all the way to the center 316 (e.g. the aperture 116 in FIGS. 1A, ID and IF) of the movable coupler 302 along the longitudinal axis 301 (which may be described in similar context to the longitudinal axis 101 in FIGS. ID to IF). The ferrite 310 (which may be described in similar context to the magnetic substructure 110 of FIGS. 1 A and IF) on which the winding 308 is adjacent to or overlays may also be circular and may have a horizontal cross-section larger than an exterior wall surface (which may be described in similar context to the exterior wall surface 108d of FIG. IE) of the winding 308.

[0078] FIG. 4A shows a perspective schematic view of yet another exemplary magnetic coupler structure 400 in accordance with one embodiment, while FIG. 4B shows an exploded view of FIG. 4A.

[0079] As seen in FIGS. 4 A and 4B, the arrangements of the various parts of the magnetic coupler structure 400 may be comparable to those of the magnetic coupler structure 200 of FIGS. 2C and 2D, while the shapes of the various parts of the magnetic coupler structure 400 may marginally differ from those of the magnetic coupler structure 200 of FIGS. 2C and 2D. Thus, corresponding descriptions relating to the arrangements of the various parts of magnetic coupler structure 200 may be applicable here. The static coupler 406 and the movable coupler 402 may be arranged spaced apart with a gap 403 therebetween. In this example, the winding being the movable coupler 402 (that may be described in similar context to the substructure-free winding 107 being the first coupler 102 of FIGS. 1A and IB) and the winding 408 of the static coupler 406 (that may be described in similar context to the second coupler 106 of FIG. IB) are bipolar coils. Each of the two ferrites 404a, 404b may be a non-planar magnetic pillar in the shape of a rectangular prism or square prism. The two ferrites 404a, 404b may be placed spaced apart from each other and may be placed at the receiving portions 418a, 418b (each being described in similar context to the receiving portion 118 in FIGS. 1A, IE and IF) of the static coupler 406 all the way to the apertures 416a, 416b (each being described in similar context to the aperature 116 in FIGS. 1A, ID and IF) of the movable coupler 402 along the longitindual axes 401a, 401b. The receiving portions 418a, 418b and the apertures 416a, 416b may be off-center of the winding 408 of the static coupler 406 and the movable coupler 402, respectively. The ferrite 410 (that may be described in similar context to the magnetic substructure 110 of FIGS. 1 A and IF) on which the winding 408 is adjacent to or overlays may follow, match or align with the rectangular exterior wall surface 408d of the winding 408. In FIGS. 4A and 4B, an exterior wall surface (which may be described in similar context to the exterior wall surface 108d of FIG. IE) of the winding 408 may be substantially of the same size as the horizontal cross-section of the ferrite 410. However, in other examples (not shown in FIGS. 4A and 4B), the exterior wall surface of the winding 408 and the horizontal cross-section of the ferrite 410 may have different sizes. It should be appreciated that some non-limiting modifications may be made to the exemplary magnetic coupler structure 400 of FIG. 4B to provide another exemplary magnetic coupler structure 400’ with a single enlarged aperture 416’ of the substructure-free winding 402’ as shown in FIG. 4C, yet another magnetic coupler structure 400” with a single enlarged receiving portion 418’ of the winding 408’ at which the two ferrites or non-planar magnetic pillars 404a, 404b are disposed as shown in FIG. 4D, and yet another magnetic coupler structure 400’” with a single enlarged aperture 416’ as well as a single enlarged receiving portion 418’ at which the two ferrites or non-planar magnetic pillars 404a, 404b are disposed as shown in FIG. 4E.

[0080] FIG. 5A shows a perspective schematic view of a further exemplary magnetic coupler structure 500 in accordance with one embodiment, while FIG. 5B shows an exploded view of FIG. 5A.

[0081] As seen in FIGS. 5 A and 5B, the magnetic coupler structure 500 may be a further enhancement of the magnetic coupler structure 300 of FIG. 3A where there are magnetic pillars 505 on the surroundings of the the static coupler 306 and the movable coupler 302. The magnetic pillars 505 may be referred to as surrounding magnetic pillars and may be described in similar context to the bordering magnetic pillar 105 of FIG. IF as discussed above. In this example, magnetic pillars may be placed in the center (e.g. 304) and boundaries (e.g. 505) of the static coupler 306 all the way to the movable coupler 302. The four magnetic pillars 505 may be arranged adjacent to and outwards from the exterior wall surface 308d of the winding 308 of the static coupler 306 and the exterior pheriphery 302d of the movable coupler 302. In other words, the four magnetic pillars 505 may be shaped and positioned in a manner to enclose the circular coils of the winding 308 and the movable coupler 302 within a squarish border (as denoted by dotted rectangle 507). Other shapes of the border may include but is not limited to circular, triangular, or polygonal. The border may also be formed based on different number of surrounding magnetic pillars.

[0082] As seen in FIG. 5B, each of the four magnetic pillars 505 may be provided by a first end region 505a, a second end region 505b opposite to the first end region 505a, and a bordering wall 505c extending between the first end region 505a and the second end region 505b. The first end region 505a may be arranged toward the static coupler 306, with a part 505c’ of the bordering wall 505c adjacent to at least a part of the exterior wall surface 308d of the winding 308 of the static coupler 306. For example, the first end region 505a of each magnetic pillar 505 may be arranged flushed with the ferrite 310. The second end region 505b may be arranged away from the static coupler 306, with another part 505c’ ’ of the bordering wall 505c adjacent to at least a part of the exterior periphery 302d of the movable coupler 302. This allows the movable coupler 302 to move alongside the bordering wall 505c toward or from the second end region 505b.

[0083] The bordering wall 505c may be formed by two flat adjacent sides 505cx, 505cy placed substantially perpendicular (e.g. at right angle) to each other, and a curved side 505cz adjoining the two flat adjacent sides 505cx, 505cy such that the horizontal crosssection of the magnetic pillar 505 may resemble a right-angled triangular-like shape where the hypotenuse is formed by the curved side 505cz that may follow or accommodate the shapes of the part of the exterior periphery 302d and the part of exterior wall surface 308d. The curved side 505cz provides the part 505c’ and the other part 505c” of the bordering wall 505c. It should be understood and appreciated that each of the magnetic pillars 505 may take other forms, shapes and dimensions (not shown in the figures) that may function individually or collectively to provide a boundary around the static coupler (e.g. 306) and the movable coupler (e.g. 302).

[0084] The description to FIGS. 3A, 3B, 4A, 4B, 5A and 5B may be adapted correspondingly for the configuration of FIG. 1C where 306, 406 may be movable and 302, 402 may be stationary instead.

[0085] Taking reference from the examples of FIGS. 2C, 2D, 3A, 3B, 4A, 4B, 5A and 5B, the winding 208, 308, 408 and the movable coupler 202, 302, 402 may be around one central magnetic pillar (e.g. 204, 304) or two magnetic pillars (e.g. 404a, 404b), while surrounding magnetic pillars (e.g. 505) may not be winded to avoid or at least minimize added cost and/or weight. Magnetic pillars 204, 304, 404a, 404b, 505 may provide paths for magnetic flux and thus enhance magnetic coupling.

[0086] Since the movable coupler 202, 302, 402 may be movable with respect to the static coupler 206, 306, 406, the gap 203, 303, 403 may be adjustable in terms of gap size. In other words, magnetic couplers e.g. the static coupler 206, 306, 406 and movable couplers 202, 302, 402 are separable for wireless power transfer (WPT) systems. The relative position and gap 203, 303, 403 between magnetic couplers may be variable. The magnetic coupler is beneficial for positioning, which addresses one of the challenges in WPT systems, and also allows the variation of gap that may meet application needs, e.g., wireless chargers for cars with different height of chassis.

[0087] It is important to note that the at least one non-planar magnetic pillar (e.g. 104, 204, 304, 404a, 404b) plays a primary role in contributing towards the improvements of the magnetic coupling structure/magnetic coupler structure (e.g. 100, 100’, 200, 300, 400, 500), in accordance with various embodiments, as compared to conventional magnetic coupler structures that do not involve a magnetic pillar (e.g. 200’ of FIG. 2A), or involve generally flat ferrite plate or core.

[0088] Significant differences in terms of overall structure and/or magnetic parameters are also observed between the magnetic coupling structure/magnetic coupler structure (e.g. 100, 100’, 200, 300, 400, 500), in accordance with various embodiments, and conventional magnetic coupler structures.

[0089] Taking the structure of FIG. 2A to represent a prior structure 200’ and comparing this with the proposed structure 200 in FIG. 2C, the geometries of both structures are set for a fair comparison, as shown in Table I. In the proposed structure 200 of FIG. 2C, there is no ferrite on the movable coupler 202 and the winding thickness of the movable coupler 202 is reduced by half. [0090] Table I

[0091] The simulated parameters for both structures are shown in Table II.

[0092] Table II

[0093] Compared with the prior structure 200’, there is the addition of a ferrite 204 (in the form of the non-planar magnetic pillar) placed on the center of the static coupler 206 and the movable coupler 202 for the proposed structure 200. This ferrite 204 not only guides the magnetic flux of the static coupler 206 to the movable coupler 202, but also serves as a fixture for the movable coupler 202 for mechanical positioning and support. It is seen from Table II that compared with the prior structure 200’, the coupling coefficient of the proposed structure 200 is enhanced, due to the guidance of the magnetic pillar 204. Also, the thinner movable coupler 202 also contributes to a larger coupling coefficient due to a smaller equivalent distance between the movable coupler 202 and the winding 208 of the static coupler 206. The self-inductance of the static coupler 206 of the proposed structure 200 is significantly larger due to the existence of the magnetic pillar (ferrite) 204. The selfinductance of the movable coupler 202 of the proposed structure 200 is only a bit (marginally) smaller. Even though the ferrite (e.g. 210b in FIG. 2B) of the movable coupler 202 is removed, the existence of the magnetic pillar 204 helps maintain a large selfinductance. Due to these factors, the power capability of the proposed structure 200 is significantly larger than that of the prior structure 200’. At the same time, the power density of movable coupler 202 of the proposed structure 200 is significantly increased or improved due to the elimination of the ferrite and the thinner size, thus reducing the weight and cost of the movable coupler 202.

[0094] In summary, the advantages of the proposed structure 200 over the prior structure 200’ may be:-

(i) increased power density of movable coupler 202;

(ii) reduced weight and cost of movable coupler 202;

(iii) increased power capability;

(iv) mechanical positioning and support by using the magnetic pillar 204.

[0095] The proposed magnetic coupler design (e.g. 102, 106; 202, 206; 302, 306; 402, 406) may be applied to the high-power wireless charging systems, such as electric buses and vessels. Using the proposed structure (e.g. 100, 100’, 200, 300, 400, 500), the power density of the movable coupler 202, 302, 402 (which may be described in similar context to the first coupler 102 or the second coupler 106 without the magnetic substructure, whichever movable) may be significantly enhanced, leading to light weight and low cost of the movable part, that is, the movable coupler 202, 302, 402.

[0096] While the invention has been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced.

Claims

1. A magnetic coupling structure comprising: a first coupler; a second coupler arranged opposite the first coupler; and at least one non-planar magnetic pillar having a longitudinal axis, wherein one of the first coupler and the second coupler is stationary, and another of the first coupler and the second coupler is movable along the at least one non-planar magnetic pillar to form and adjust a gap between the first coupler and the second coupler along the longitudinal axis.

2. The magnetic coupling structure as claimed in claim 1, wherein the first coupler is made up of only a substructure-free winding, and is shaped to provide: a first surface arrangeable to face towards the second coupler; a second surface opposite to the first surface, the second surface arrangeable to face away from the second coupler; an interior periphery extending between the first surface and the second surface, the interior periphery defining an aperture configured to receive a portion of the at least one non-planar magnetic pillar along the longitudinal axis; and an exterior periphery being opposite to the interior periphery and extending between the first surface and the second surface.

3. The magnetic coupling structure as claimed in claim 2, wherein the second coupler comprises a winding being shaped to provide: a first plane arrangeable to face towards the first surface of the first coupler; a second plane opposite to the first plane, the second plane arrangeable to face away from the first coupler; an interior wall surface extending between the first plane and the second plane, the interior wall surface defining a receiving portion configured to receive another portion of the at least one non-planar magnetic pillar along the longitudinal axis; and

24 an exterior wall surface being opposite to the interior wall surface and extending between the first plane and the second plane.

4. The magnetic coupling structure as claimed in claim 3, wherein the second coupler further comprises a magnetic substructure adjacent to the winding; and wherein the second plane of the winding is arrangeable to face towards the magnetic substructure.

5. The magnetic coupling structure as claimed in claim 3, wherein the winding is free from a magnetic substructure such that the second coupler is made up of only the winding.

6. The magnetic coupling structure as claimed in any one of claims 3 to 5, wherein the substructure-free winding is different in size as compared to the winding.

7. The magnetic coupling structure as claimed in any one of claims 3 to 6, wherein the substructure-free winding has a thickness different from that of the winding.

8. The magnetic coupling structure as claimed in claim 7, wherein the thickness of the substructure-free winding is half that of the winding.

9. The magnetic coupling structure as claimed in any one of claims 3 to 8, wherein the at least one non-planar magnetic pillar comprises: a proximal end; a distal end opposite to the proximal end; and a wall extending along the longitudinal axis between the proximal end and the distal end, the proximal end configured to be received by either: the receiving portion of the winding when the second coupler is stationary and the first coupler is movable; or the aperture of the substructure-free winding when the first coupler is stationary and the second coupler is movable.

10. The magnetic coupling structure as claimed in claim 9, wherein the other of the first coupler and the second coupler is movable along the wall towards or away from the distal end.

11. The magnetic coupling structure as claimed in claim 9 or 10, wherein the at least one non-planar magnetic pillar is disposed at the receiving portion of the winding when the second coupler is stationary and the first coupler is movable, and the at least one non-planar magnetic pillar extends at least partially through the aperture of the substructure-free winding such that the winding and the substructure-free winding surround at least part of the wall of the at least one non-planar magnetic pillar.

12. The magnetic coupling structure as claimed in claim 9 or 10, wherein the substructure-free winding is further shaped to provide a further interior periphery extending between the first surface and the second surface, the further interior periphery defining a further aperture configured to receive a further portion of the at least one non-planar magnetic pillar along the longitudinal axis; wherein the winding is further shaped to provide a further interior wall surface extending between the first plane and the second plane, the further interior wall surface defining a further receiving portion configured to receive another further portion of the at least one non-planar magnetic pillar along the longitudinal axis; and wherein each of the at least one non-planar magnetic pillar is disposed correspondingly at the receiving portion and the further receiving portion of the winding when the second coupler is stationary and the first coupler is movable, and each the at least one non-planar magnetic pillar extends correspondingly and at least partially through the aperture and the further aperture of the substructure-free winding such that the winding and the substructure-free winding surround at least part of the wall of each of the at least one non-planar magnetic pillar.

13. The magnetic coupling structure as claimed in claim 9 or 10, wherein the at least one non-planar magnetic pillar is disposed at the aperture of the substructure-free winding when the first coupler is stationary and the second coupler is movable, and the at least one non-planar magnetic pillar extends through the receiving portion of the winding such that the winding and the substructure-free winding surround at least part of the wall of the at least one non-planar magnetic pillar.

14. The magnetic coupling structure as claimed in claim 9 or 10, wherein the substructure-free winding is further shaped to provide a further interior periphery extending between the first surface and the second surface, the further interior periphery defining a further aperture configured to receive a further portion of the at least one non-planar magnetic pillar along the longitudinal axis; wherein the winding is further shaped to provide a further interior wall surface extending between the first plane and the second plane, the further interior wall surface defining a further receiving portion configured to receive another further portion of the at least one non-planar magnetic pillar along the longitudinal axis; and wherein each of the at least one non-planar magnetic pillar is disposed correspondingly at the aperture and the further aperture of the substructure-free winding when the first coupler is stationary and the second coupler is movable, and each the at least one non-planar magnetic pillar extends correspondingly and at least partially through the receiving portion and the further receiving portion of the winding such that the winding and the substructure-free winding surround at least part of the wall of each of the at least one non-planar magnetic pillar.

15. The magnetic coupling structure as claimed in any one of claims 9 to 14, wherein the wall has non-uniform sections.

16. The magnetic coupling structure as claimed in any one of claims 3 to 15, further comprising at least one bordering magnetic pillar comprising: a first end region; a second end region opposite to the first end region; and a bordering wall extending between the first end region and the second end region, wherein the first end region is arranged toward the second coupler when the second coupler

27 is stationary and the first coupler is movable, with a part of the bordering wall adjacent to at least a part of the exterior wall surface of the winding, the second end region is arranged away from the second coupler, with another part of the bordering wall adjacent to at least a part of the exterior periphery of the first coupler, thereby allowing the first coupler to move alongside the bordering wall toward or from the second end region.

17. The magnetic coupling structure as claimed in any one of claims 3 to 15, further comprising at least one bordering magnetic pillar comprising: a first end region; a second end region opposite to the first end region; and a bordering wall extending between the first end region and the second end region, wherein the first end region is arranged toward the first coupler when the first coupler is stationary and the second coupler is movable, with a part of the bordering wall adjacent to at least a part of the exterior periphery of the first coupler, the second end region is arranged away from the first coupler, with another part of the bordering wall adjacent to at least a part of the exterior wall surface of the winding, thereby allowing the second coupler to move alongside the bordering wall toward or from the second end region.

18. The magnetic coupling structure as claimed in claim 16 or 17, wherein the at least one bordering magnetic pillar is free from being encircled by the winding and the substructure-free winding.

19. The magnetic coupling structure as claimed in claim 18, wherein the at least one bordering magnetic pillar comprises a plurality of bordering magnetic pillars arranged spaced apart from one another around at least part of the exterior wall surface of the winding and at least part of the exterior periphery of the first coupler.

20. The magnetic coupling structure as claimed in any one of claims 1 to 19, wherein the at least one non-planar magnetic pillar comprises ferrite.

28