CN117501391A

CN117501391A - Multi-layer coupler for wireless power transmission

Info

Publication number: CN117501391A
Application number: CN202180092911.XA
Authority: CN
Inventors: 胡晓磊; 黄康川
Original assignee: Xineng New Energy Technology Pte Ltd
Current assignee: Xineng New Energy Technology Pte Ltd
Priority date: 2021-02-03
Filing date: 2021-02-03
Publication date: 2024-02-02
Also published as: EP4288986A1; WO2022169404A1; EP4288986A4

Abstract

The application proposes a multilayer coupler for wireless power transmission, comprising a coil for wireless power transmission based on magnetic induction technology and having a multilayer winding structure; the multi-layer winding structure comprises a plurality of winding layers, wherein each winding layer comprises a plurality of winding turns; for each of the plurality of winding layers, a plurality of intermediate winding turns of the plurality of winding turns in the winding layer including one or more transition portions at locations where a corresponding coil transition of the coil occurs between the intermediate winding turn of the winding layer and a winding turn of another winding layer; the present application proposes a system for wireless power transfer, the system comprising a wireless power transmitter comprising a multi-layer coupler and/or a wireless power receiver comprising a multi-layer coupler; the present application also includes methods of manufacturing the multilayer coupler and methods of wireless power transfer using the multilayer coupler.

Description

Multi-layer coupler for wireless power transmission

Technical Field

The present invention relates to wireless power transmission based on magnetic induction technology, and more particularly, to a multi-layered coupler for wireless power transmission and a method of manufacturing the same, a wireless power transmitter including the multi-layered coupler, a wireless power receiver including the multi-layered coupler, a wireless power transmission system including the wireless power transmitter and/or the wireless power receiver, and a method of performing wireless power transmission using the multi-layered coupler.

Background

Wireless Power Transfer (WPT), which may also be referred to as Inductive Power Transfer (IPT), based on magnetic induction technology has been widely used in numerous applications for charging or powering, such as electronic devices, medical implant devices, automated guided vehicles, robots, electric vehicles, etc., where safety and/or convenience are involved. For example, in WPT systems for charging applications, coils may be provided that act as couplers (i.e., magnetic couplers), with charging pads used as transmitters (Tx) and receivers (Rx). Power may be transmitted wirelessly through magnetic coupling between the transmitter and receiver coils, the principle of operation of which is similar to a transformer. Furthermore, the physical isolation between the transmitter coil and the receiver coil provides electrical isolation and avoids mechanical wear occurring in contact chargers.

The design/configuration of the magnetic coupler is the focus of WPT systems. For example, the main uses of magnetic couplers are power transfer by magnetic induction techniques, which affect the performance of WPT systems including, for example, efficiency, air gaps and misalignments between transmitters and receivers, voltage gain, and Electromagnetic (EM) noise emissions. For example, high electromagnetic noise emissions may interfere with other electronic devices in the vicinity. However, in conventional designs/configurations of magnetic couplers (i.e., coils), the problem of electromagnetic noise emissions is often ignored, but this can be a critical factor in the design/configuration implementation in commercial products or equipment. For example, for a product to be sold, the product may need to meet international and regional standards defining maximum limits on electromagnetic noise emissions. This may also be applicable to various applications utilizing Alternating Current (AC) in the coil, such as induction heating and induction cooktops, where power is wirelessly transferred from the induction heating assembly to the object to be heated.

Accordingly, there is a need to provide a coupler (i.e., a magnetic coupler) for wireless power transfer that seeks to overcome or at least ameliorate one or more of the disadvantages of conventional couplers for wireless power transfer, such as, but not limited to, reducing or minimizing EM noise emissions. The present invention has been developed in this context.

Disclosure of Invention

According to a first aspect of the present invention, there is provided a multi-layer coupler for wireless power transmission, the multi-layer coupler comprising:

a coil for wireless power transmission based on magnetic induction technology and having a multi-layer winding structure; the multi-layer winding structure comprises a plurality of winding layers, wherein each winding layer comprises a plurality of winding turns;

for each of the plurality of winding layers, a plurality of intermediate winding turns of the plurality of winding turns in the winding layer include one or more transition portions at locations where a corresponding coil transition of the coil occurs between the intermediate winding turn of the winding layer and a winding turn of another winding layer.

According to a second aspect of the present invention, there is provided a wireless power transmitter comprising:

a power supply configured to generate a time-varying current;

the multi-layer coupler according to the first aspect of the present invention described above, which acts as a transmitting coupler and is connected to the power supply, wherein the transmitting coupler is configured to receive a time-varying current from the power supply to generate a magnetic field and to perform wireless power transfer between air gaps in cooperation with a receiving coupler based on magnetic induction technology.

According to a third aspect of the present invention, there is provided a wireless power receiver comprising:

an electrical load; and

the multi-layer coupler according to the first aspect of the present invention described above is used as a receiving coupler and connected to the electric load, wherein the receiving coupler is configured to couple with a magnetic field generated from a transmitting coupler to induce a current in the receiving coupler for powering the electric load, the electric load being connected to the receiving coupler to perform wireless power transmission between air gaps in cooperation with the transmitting coupler based on magnetic induction technology.

According to a fourth aspect of the present invention, there is provided a system for wireless power transmission, the system comprising:

a wireless power transmitter, comprising:

a power supply configured to generate a time-varying current;

a transmit coupler connected to a power source, wherein the transmit coupler is configured to receive a time-varying current from the power source for generating a magnetic field for wireless power transfer between air gaps based on magnetic induction technology in cooperation with the receive coupler;

a wireless power receiver, comprising:

an electrical load; and

a receive coupler connected to the electrical load, wherein the receive coupler is configured to couple with a magnetic field generated by the transmit coupler to induce a current in the receive coupler, power the electrical load connected to the receive coupler to cooperate with the transmit coupler for wireless power transfer between the air gaps based on magnetic induction technology,

Wherein at least one of the transmit coupler and the receive coupler is a multi-layer coupler according to the first aspect of the invention described above, and the wireless power transmitter and the wireless power receiver are separated by an air gap.

According to a fifth aspect of the present invention, there is provided a multi-layered coupler manufacturing method for wireless power transmission, the method comprising:

a coil for wireless power transmission based on magnetic induction technology is configured, the coil having a multi-layer winding structure comprising a plurality of winding layers, each of the plurality of winding layers comprising a plurality of winding turns,

wherein, for each of the plurality of winding layers, where a corresponding coil transition of the coil occurs between an intermediate winding turn of the winding layer of the plurality of winding layers and a winding turn of another winding layer, at least each intermediate winding turn of the plurality of intermediate winding turns of the plurality of winding turns within the winding layer comprises one or more transition portions.

According to a sixth aspect of the present invention, there is provided a wireless power transmission method comprising:

generating a time-varying current by a power source at the wireless power transmitter; and

receiving a time-varying current from a power source through a transmitting coupler at a wireless power transmitter connected to the power source to generate a magnetic field, performing wireless power transmission between air gaps based on magnetic induction technology in cooperation with the receiving coupler;

Coupling a magnetic field generated by a receiving coupler and a transmitting coupler at a wireless power receiver connected to an electrical load to induce a current in the receiving coupler, thereby performing wireless power transmission between air gaps in cooperation with the transmitting coupler based on magnetic induction technology; and

power is supplied to an electrical load connected thereto based on a current induced therein through a receiving coupler at the wireless power receiver,

at least one of the transmitting coupler and the receiving coupler is a multi-layered coupler according to the first aspect of the present invention described above, and the wireless power transmitter and the wireless power receiver are separated by an air gap.

Drawings

Embodiments of the present invention will be better understood by those skilled in the art from the following description, by way of example only, taken in conjunction with the accompanying drawings:

FIGS. 1A-1F are schematic diagrams of conventional couplers having various configuration/shape examples;

FIG. 2A is a perspective view of an example of a conventional coupler having a single layer winding;

FIG. 2B is a perspective view of an example of a conventional coupler with multiple layers of windings;

FIG. 3 is an exemplary schematic diagram of a conventional multi-layer coupler formed by stacking a plurality of single-layer couplers into two layers;

FIG. 4 is a perspective view and a schematic cross-sectional view of an example of a conventional double-layer coupler;

FIG. 5 is a simplified schematic diagram of a conventional rectangular double-layer coupler in which the coils are configured or wound according to a first conventional winding strategy;

fig. 6A and 6B are schematic diagrams of coils configured or wound according to a first conventional winding strategy, namely a conventional coil example with aligned winding layers (fig. 6A) and a conventional coil example with non-aligned winding layers (fig. 6B);

FIG. 7 is an example of a conventional double-layer coupler having coils configured according to a first conventional winding strategy, each coil having two wires bundled together;

fig. 8A and 8B are perspective views (fig. 8A) and top views (fig. 8B) of an example of a conventional four-layer PCB coil configured according to a first conventional winding strategy;

FIG. 9 is a schematic cross-sectional view of a second example conventional multilayer coupler configured according to a second conventional winding strategy or winding sequence;

FIG. 10 is a simplified schematic diagram of a conventional rectangular double-layer coupler in which the coil is wound according to a second conventional winding strategy;

FIG. 11A is a conventional five-layer coupler including a coil configured according to a second conventional winding strategy;

FIG. 11B is a conventional four-layer coupler including a coil configured according to a second conventional winding strategy;

FIGS. 12A and 12B are schematic diagrams of a multi-layer coupler for wireless power transfer in accordance with various embodiments of the present invention;

fig. 13 is a schematic diagram of a system for wireless power transfer in accordance with various embodiments of the invention;

fig. 14 is a schematic flow chart diagram of a wireless power transmission method in accordance with various embodiments of the present invention;

fig. 15 is a flow chart of a method of manufacturing a multi-layer coupler for wireless power transfer in accordance with various embodiments of the present invention;

FIG. 16 is a cross-sectional schematic cross-sectional view of a first example multilayer coupler in accordance with various embodiments of the invention, and a first winding sequence (based on the number of winding turns or coils) of a multilayer winding structure for forming coils, the first winding sequence being illustrated or represented by arrows;

17A-17C are simplified schematic diagrams of examples of rectangular multi-layer couplers, each including a coil configured to have a multi-layer winding structure according to a first winding sequence, in accordance with various embodiments of the invention;

FIG. 18 is a cross-sectional schematic cross-sectional view of various exemplary multilayer couplers in accordance with various embodiments of the invention and winding sequence for forming a multilayer winding structure of a coil illustrated or represented by arrows;

FIG. 19 is a schematic cross-sectional view of a second exemplary multilayer coupler, and a second winding sequence of a multilayer winding structure for forming a coil, the second winding sequence being illustrated or represented by an arrow, in accordance with various embodiments of the invention;

FIGS. 20A-20C are simplified schematic diagrams of rectangular multi-layer couplers, each including a coil configured to have a multi-layer winding structure according to a second winding sequence, in accordance with various embodiments of the invention;

FIG. 21 is a cross-sectional schematic cross-sectional view of various exemplary multilayer couplers and associated winding sequences for forming a multilayer winding structure of a coil, illustrated or represented by arrows, in accordance with various embodiments of the invention;

FIG. 22 is a schematic cross-sectional view of a third exemplary multilayer coupler and a third winding sequence for forming a multilayer winding structure of a coil, the sequence being illustrated or represented by arrows, in accordance with various embodiments of the present invention;

FIGS. 23A and 23B are simplified schematic diagrams of rectangular multi-layer couplers, each comprising a coil, configured in accordance with various embodiments of the invention in a second winding sequence having a multi-layer winding structure in which each winding turn has a plurality of transition sections;

FIG. 24 is a schematic diagram of a conventional multilayer coupler configured according to a first conventional winding sequence and a second conventional winding sequence, respectively, wherein winding turns in each winding layer are connected in series;

FIG. 25 is a schematic perspective view of a conventional multilayer coupler configured according to a first conventional winding sequence, while showing the formation of parasitic capacitances between coils of adjacent winding layers;

FIG. 26A is a simplified schematic diagram of a rectangular multi-layer coupler including three coil units stacked to form additional layers of coil units and independently connected in accordance with various embodiments of the invention;

FIG. 26B is a simplified schematic diagram of a rectangular multi-layer coupler including three coil units stacked to form additional layers of coil units and connected in series, in accordance with various embodiments of the invention;

FIG. 26C is a simplified schematic diagram of a rectangular multi-layer coupler formed from three stacked coil units, forming additional layers of coil units and connected in parallel, in accordance with various embodiments of the invention;

fig. 27A and 27B are ac current measurements (ac current waveforms) in a multilayer coupler configured in the second winding order and a conventional multilayer coupler configured in the first conventional winding order, respectively, according to various embodiments.

Detailed Description

Various embodiments of the present invention relate to Wireless Power Transfer (WPT) (also known as Inductive Power Transfer (IPT)) based on magnetic induction technology. In particular, various embodiments of the present invention provide a multi-layer coupler for wireless power transfer (which may also be referred to as a wireless power transfer multi-layer coupler (i.e., a magnetic multi-layer coupler)) and a method of manufacturing the same. Various embodiments of the present invention also provide a wireless power transmitter including the above-described multi-layer coupler (which may be referred to as a multi-layer transmit coupler), and a wireless power receiver including the above-described multi-layer coupler (which may be referred to as a multi-layer receive coupler). Various embodiments of the present invention further provide a wireless power transmission system including the above-described wireless power transmitter and/or wireless power receiver, and a wireless power transmission method using the above-described multi-layer coupler.

The design of the coupler (which may be, for example, a coil, or may include a coil) is versatile and suitable for a variety of purposes and applications. For example, the coupler may be made from round wire, flat wire, magnetic wire bundles, printed Circuit Board (PCB) traces, or various combinations thereof, as the case may be. Further, the coil may have various shape configurations such as, but not limited to, a spiral, circular, or ring shape 100 (as shown in fig. 1A), a rectangle 102 (as shown in fig. 1B), a triangle 104 (as shown in fig. 1C), an oval 106 (as shown in fig. 1D), a polygon (hexagon 108 as shown in fig. 1E, or pentagon 110 as shown in fig. 1F), or any other suitable shape.

Furthermore, the coupler may also be designed or configured to have a single-layer winding structure (abbreviated as single-layer winding) or a multi-layer winding structure (abbreviated as multi-layer winding). For example, a coupler having a single-layer winding structure may be referred to as a single-layer coupler, and a coupler having a multi-layer winding structure may be referred to as a multi-layer coupler. For example, multi-layer windings may be used in various compact applications because higher inductances may be obtained with the same area. As an example, fig. 2A is a perspective view of a conventional coupler 200 having a single layer winding, and fig. 2B is a perspective view of a conventional coupler 210 having a multi-layer winding (or more specifically, a double layer winding).

Traditionally, several (or more) single-layer couplers may also be stacked to form a multi-layer coupler, as multiple receivers, for multi-frequency operation. Fig. 3 is a schematic diagram showing a conventional multi-layer coupler 300 formed by stacking a plurality of single-layer couplers into two layers.

Various embodiments of the present invention indicate that the design or configuration of the multilayer winding can affect parasitic impedance in the coupler and the resulting electromagnetic noise emissions. Traditionally, the winding strategy of multi-layer windings (also referred to herein as winding techniques) is not sufficient, regardless of the coil shape and wire material. For this purpose, two conventional multilayer winding strategies will be exemplified below.

Fig. 4 is a perspective view of a first example conventional double-layer coupler 400, and a schematic cross-sectional view of a section thereof. As shown in fig. 4, in the winding strategy associated with the first example conventional multilayer coupler 400, the coil is wound from one side or end (first side or end, corresponding to the innermost or outermost winding turn relative to the center or core of the first example conventional multilayer coupler 400) to the other side or end (second side or end, corresponding to the outermost or innermost winding turn relative to the first example conventional multilayer coupler 400 (opposite the first side or end)), then continues in the same manner, but in the opposite winding direction (i.e., from the second side or end to the first side or end) in the next or subsequent winding layer (e.g., layer 2), and so on. In particular, in fig. 4, a winding sequence (based on the number of windings or loops) according to a winding strategy associated with the first example conventional multi-layer coupler 400 is represented by arrow 410. Such a conventional winding strategy or winding sequence may be referred to herein as a first conventional winding strategy or winding sequence.

As an example, fig. 5 is a simplified schematic diagram of a conventional rectangular double-layer coupler 500 (i.e., having two winding layers), with coils configured or wound according to a first conventional winding strategy. In the simplified schematic shown in fig. 5, the winding turns indicated by full lines correspond to a first layer of the coil, while the winding turns indicated by broken lines correspond to a second layer of the coil. As shown in fig. 5, each winding layer may include four winding turns for ease of illustration and without limitation. For simplicity and ease of comparison, the same or similar types of simplified schematic diagrams (i.e., simplified rectangular schematic diagrams) may be used to illustrate or represent the various configurations/designs of the multilayer couplers described herein. It will be appreciated by those skilled in the art that the invention is not limited to coils having a rectangular shape, but may have any other suitable shape. Furthermore, in such a simplified schematic diagram, it will be further understood by those skilled in the art that winding turns of different layers, but at the same turn position, may be shown immediately adjacent to each other for illustrative purposes only, but that these winding turns of different winding layers may actually lie directly above each other with respect to an axis (e.g., a vertical axis).

Fig. 6A and 6B are schematic diagrams of a coil 604 and a coil 608, respectively, configured or wound according to a first conventional winding strategy, wherein the coil 604 has aligned winding layers and the coil 608 has non-aligned winding layers (or shifted winding layers). In fig. 6B, it is shown that the position of one winding layer may be offset relative to another winding layer of the coil 608 (e.g., in a transverse direction, or in a radial direction where the coil is configured as a circle). In fig. 6A and 6B, it is also shown that coil 604 and coil 608 are not limited to having two winding layers, and may have any number of winding layers as desired or appropriate.

A first conventional winding strategy may be used in a commercial double-layer coupler, as shown in fig. 4 and 7. Specifically, the double-layer coupler 400 shown in fig. 4 includes a coil configured according to a first conventional winding strategy, each winding turn having one wire, while the double-layer coupler 400 shown in fig. 7 includes a coil configured according to a first conventional winding strategy, each winding turn having two wires bundled together.

There is also a first conventional winding strategy in a conventional four-layer Printed Circuit Board (PCB) coil. As an example, fig. 8A and 8B are a perspective view (fig. 8A) and a top view (fig. 8B) of the coil, respectively. Fig. 8A and 8B are perspective and top views (fig. 8A) of a conventional four-layer PCB coil 800 configured according to a first conventional winding strategy, respectively (fig. 8B).

Fig. 9 is a schematic cross-sectional view of a second example conventional multilayer coupler 900 configured according to a second conventional winding strategy or winding sequence. In a second conventional winding strategy associated with the second example conventional multilayer coupler 900, as shown in fig. 9, the coil is configured or wound (in the form of winding turns or coils) from one side or end (first side or end corresponding to the innermost or outermost winding turn relative to the center or core of the second example conventional multilayer coupler 900) to the other side or end (second side or second end corresponding to the outermost or innermost winding turn (opposite the first side or first end) relative to the center or core of the second example conventional multilayer coupler 900) and then continues winding in the same manner and in the same winding direction (i.e., from the first side or first end to the second side or second end) in the next or subsequent winding layer (e.g., layer 2), and so on. In particular, in fig. 9, the winding sequence (based on the number of windings or loops) according to the second winding strategy is represented by arrow 910. Such a conventional wire winding strategy or wire winding sequence may be referred to herein as a second conventional wire winding strategy or wire winding sequence.

By way of example, fig. 10 is a simplified schematic diagram of a conventional rectangular double-layer coupler 1000 (having two winding layers), the coil also being wound according to a second conventional winding strategy. As shown in fig. 10, each winding layer may include four winding turns for purposes of illustration and not limitation.

A second conventional winding strategy is also found in conventional double layer couplers (as shown in fig. 11A and 11B). In particular, FIG. 11A is a conventional five-layer coupler 1104 including coils configured according to a second conventional winding strategy; fig. 11B is a conventional four-layer coupler 1108 that includes a coil configured according to a second conventional winding strategy.

However, as can be appreciated from the various embodiments of the present invention, conventional multilayer couplers configured based on conventional winding strategies (or winding techniques), such as the first or second conventional winding strategies described above, can create higher parasitic capacitances in the coil. However, various embodiments of the present invention have also found that such conventional winding strategies can create multiple low impedance paths at different frequencies, thereby undesirably increasing the electromagnetic noise emission profile.

Thus, it is appreciated from the various embodiments of the present invention that conventional multilayer couplers may be adversely affected by high electromagnetic noise emissions. Accordingly, various embodiments of the present invention provide a multi-layer coupler (i.e., a magnetic multi-layer coupler) for wireless power transmission that aims to overcome or at least ameliorate one or more drawbacks of conventional multi-layer couplers for wireless power transmission, such as, but not limited to, reducing or minimizing electromagnetic noise emissions.

Fig. 12A is a schematic diagram of a multi-layer coupler 1200 for wireless power transfer in accordance with various embodiments of the invention. The multilayer coupler 1200 includes a coil 1204 configured for wireless power transfer based on magnetic induction technology having a multilayer winding structure including a plurality of winding layers 1208, each winding layer of the plurality of winding layers 1208 including a plurality of winding turns 1212. In particular, for each of the plurality of winding layers 1208, at least each of the plurality of intermediate winding turns of the plurality of winding turns 1212 of the winding layer includes one or more transition portions 1216 at which transition portions 1216 a corresponding coil transition of the coil occurs between the intermediate winding turn of the winding layer and the winding turn of another of the plurality of winding layers 1208. Such a coil transition between one winding turn of one winding layer and one winding turn of another winding layer may also be referred to herein as an inter-layer coil transition (or simply an inter-layer transition).

The term "winding turn" (also simply referred to as "turn") is well known to those skilled in the art in couplers for wireless power transmission and therefore need not be described or defined herein. For example, as shown in fig. 12A, one turn of the winding corresponds to a portion or segment of the coil being wound one turn around a center or core (e.g., an air core), each turn of the winding being represented as one turn. It will be appreciated by those skilled in the art that the winding turns may be entirely wound, or at least substantially wound, on the core or core, particularly the intermediate winding turns. In view of practical implementation, one or more winding turns may not be fully wound around the center or core, e.g. the winding turns are directly coupled or lead to the input (or input portion) or output (or output portion) of the coil.

Fig. 12A shows a coil 1204 having a multi-layer winding structure that includes a plurality of winding layers 1208, each including a plurality of winding turns 1212, but in fact does not show or define various details or parameters (e.g., shape, size/dimensions, etc.) of the coil 1204. In other words, those skilled in the art will appreciate that the coil 1204 is not limited to the shape and/or size shown in fig. 12A. Although not explicitly shown in fig. 12A, the plurality of winding turns 1212 of the plurality of winding layers 1208 are electrically connected because they may form one continuous winding in its entirety by winding the coil 1204.

In various embodiments of the present invention, the intermediate winding turn of a winding layer refers to the winding turn between the innermost winding turn and the outermost winding turn of the winding layer. Thus, the plurality of intermediate winding turns of the winding layer described above refers to any plurality (two or more) of winding turns between the innermost winding turn and the outermost winding turn of the winding layer.

The plurality of intermediate winding turns may correspond to all or a subset (i.e., not all) of the plurality of winding turns, including the one or more transition portions 1216 (i.e., portions where inter-layer coil transitions occur), and the plurality of intermediate winding turns may be disposed along the winding layers according to a predetermined pattern, such as periodically. When the coil transitions from another winding layer to one winding turn position of the winding layer (e.g., at winding turn position 1), the next intermediate winding turn position of the winding layer where the inter-layer coil transition occurs may be located two or more winding turn positions (e.g., at winding turn positions 3 or 4) away from the winding turn position. Thus, the predetermined pattern may be one predetermined winding turn position. The predetermined pattern may be the same or different in the plurality of winding layers.

In various embodiments, the coil 1204 may be suitably made of round wire, flat wire, magnet wire bundles, printed Circuit Board (PCB) traces, or various combinations thereof, as desired. Further, the coil may be made of a single wire or a wire harness including a plurality of wires bundled together (e.g., in parallel or stranded fashion), such as an insulated wire harness stranded together in the case of high frequency wires (e.g., litz wire).

Thus, the coil 1204 is configured to have a multi-layer winding structure, for each of the plurality of winding layers, at least each of the plurality of intermediate winding turns of the winding layers including one or more transition portions at which a corresponding coil transition (inter-layer coil transition) of the coil occurs between the intermediate winding turn and a winding turn of another of the plurality of winding layers. As a result, at least a plurality of winding turns of the winding layer between an innermost winding turn and an outermost winding turn of the winding layer include one or more of the above-described transition portions, which have been found to advantageously reduce or minimize effective parasitic capacitance (or optimize impedance) in the multilayer coupler 1200, thereby reducing or minimizing electromagnetic noise emissions of the multilayer coupler 1200. In particular, various embodiments of the present invention find that by configuring at least each of the aforementioned plurality of intermediate winding turns of a winding layer with one or more of the aforementioned transition portions for each of a plurality of winding layers, parasitic capacitances in the multilayer coupler 1200 can be advantageously distributed (e.g., across the plurality of winding layers and the plurality of winding turns) to reduce or minimize effective parasitic capacitances (or optimize impedances) in the multilayer coupler 1200. These advantages or technical effects will become more apparent to one skilled in the art as various embodiments of the present invention describe the multi-layer coupler 1200 in greater detail.

In various embodiments, for each of the plurality of winding layers described above, each of the plurality of winding turns of the winding layer includes one or more transition portions at which a respective coil transition of the coil occurs between the winding turn of the winding layer and a winding turn of another winding layer of the plurality of winding layers. That is, for each of the plurality of winding layers 1208, each of the plurality of winding turns 1212 of the winding layer includes the plurality of intermediate winding turns described above including one or more transition portions. For example, the plurality of winding turns 1212 may include an outermost (or first) winding turn, the plurality of intermediate winding turns described above, and an innermost (or last) winding turn. As another example, the plurality of winding turns 1212 may be all of the winding turns of the winding layer.

In various embodiments, for each of the plurality of winding layers and each of the plurality of intermediate winding turns of the winding layer, the intermediate winding turn of the winding layer between which the corresponding coil transition of the coil occurs and the winding turn of the other winding layer are winding turns at the same winding turn position (e.g., relative to the corresponding winding layer). In other words, as shown in fig. 2, the corresponding coil transitions are located between winding turns at the same winding turn position. The winding turn positions of the winding layers refer to the winding turn positions in the winding layers (i.e., relative to the winding layers) in various embodiments of the invention as described below with reference to fig. 16. For example, the winding turn positions may be represented based on any reference or number as appropriate. By way of example only and not limitation, the outermost winding turn may be referred to as being at winding turn position 1, the immediately subsequent winding turn may be referred to as being at winding turn position 2, and so on up to the innermost winding turn, as described in fig. 6B and 9. Thus, the winding turn bits may also be referred to as a winding turn index.

In various embodiments, for each of the plurality of winding layers and for one or more intermediate winding turns of the plurality of intermediate winding turns of the winding layer, the winding turn of the winding layer between which the corresponding coil transition of the coil occurs and the intermediate winding turn of the other winding layer are winding turns at different winding turn positions (e.g., relative to the corresponding winding layer). In other words, as shown in fig. 22, the corresponding coil transitions are located between winding turns at different winding turn positions.

In various embodiments, the plurality of winding turns 1212 of each of the plurality of winding layers 1208 collectively form a plurality of axial winding turn groups (e.g., longitudinal groups), each axial winding turn group including winding turns at the same winding turn position (e.g., relative to the corresponding winding layer). For more detailed description, fig. 12A and 12B are schematic diagrams of a multi-layer coupler 1200, but fig. 12B further illustrates winding turns of a plurality of axial winding turn groups. In fig. 12B, each axial winding turn group includes winding turns of the plurality of winding layers 1208 at the same winding turn location. As an example, the outermost axial winding turn group includes all winding turns of the plurality of winding layers at winding turn position 1, the immediately adjacent axial winding turn group includes all winding turns of the plurality of winding layers at winding turn position 2, and so on.

In various embodiments, in each of the plurality of axial winding turn groups 1220, for each winding turn except for the last (or final) winding turn of the axial winding turn group 1220, the winding turn includes a first transition portion of one or more transition portions 1216 at which a corresponding coil transition of the coil occurs between the winding turn and another winding turn of the axial winding turn group.

In various embodiments, for each winding turn except for the last (or final) winding turn in the set of axial winding turns, at a first transition portion of the winding turn, a corresponding coil transition of the coil occurs from that winding turn to the immediately adjacent (or subsequent) winding turn in the set of axial winding turns.

In various embodiments, for each pair of adjacent axial winding turn groups 1220 in the first axial winding turn group of the pair, for each winding turn other than the last (or final) winding turn in the axial winding turn group, at a first transition portion of the winding turn, a corresponding coil transition of the coil occurs in a first transition direction in the axial winding turn group from the winding turn to its immediately adjacent winding turn, and for each winding turn other than the last winding turn in the second axial winding turn group of the pair, at the first transition portion of the winding turn, a corresponding coil transition of the coil occurs in a second transition direction in the axial winding turn group from the winding turn to its immediately adjacent winding turn. Here, the first transition direction and the second transition direction are opposite to each other. In other words, as shown in fig. 16, the winding turns in adjacent axial winding turn groups are wound in opposite transitional directions with respect to the axial direction (e.g., longitudinal lines).

In various embodiments, for each pair of immediately adjacent axial winding turn groups 1220 in the first axial winding turn group of the pair, for each winding turn other than the last (or final) winding turn in the axial winding turn group, at a first transition portion of the winding turn, a corresponding coil transition of the coil occurs in a first transition direction from the winding turn in the axial winding turn group to an immediately adjacent winding turn, and in the second axial winding turn group of the pair, at the first transition portion of the winding turn, a corresponding coil transition of the coil occurs in the axial winding turn group at a location from the winding turn to an immediately adjacent winding turn in the first transition direction. In other words, as shown in fig. 19, the winding turns in adjacent axial winding turn groups are wound in the same transitional direction with respect to the axial direction (e.g., longitudinal line).

In various embodiments, the last winding turn in the first axial winding turn group includes a second transition portion at which the coil transitions to the first winding turn in the second axial winding turn group. Here, the first winding turn and the last winding turn in the second axial winding turn group are located at opposite ends of the second axial winding turn group. As shown in fig. 16, if the winding turn of layer 2 winding turn bit 1 is the last winding turn of the first axial winding turn group, the winding turn includes a second transition portion where the coil transitions to the first winding turn (layer 2 winding turn bit) of the second axial winding turn group (winding turn bit 2). As shown in fig. 19, if the winding turn at winding turn position 1 of layer 2 is the last winding turn of the first axial winding turn group, the winding turn includes a second transition portion where the coil transitions to the first winding turn (winding turn position 1) of the second axial group (winding turn position 2). Thus, in various embodiments, the first and last winding turns of the axial winding turn group may be defined with respect to a coil transition direction across winding turns in the axial winding turn group, in other words, with respect to a start position (corresponding to the first winding turn) and an end position (corresponding to the last winding turn) of a coil transition across winding turns within the axial winding turn group.

In various embodiments, in each of the plurality of axial winding turn groups 1220, the first transition portion of each winding turn of the axial winding turn groups is at least substantially aligned with respect to the axial direction (e.g., along the longitudinal line). In various embodiments, in each of the plurality of winding layers, the first transition portion of each winding turn in the winding layer is at least substantially aligned with respect to the transverse direction (e.g., along a transverse line). As shown in fig. 20B, the transition portions (corresponding to the first transition portions described above) are aligned with respect to the longitudinal and transverse lines, in other words, at the same corresponding portions of the winding turns.

In various embodiments, for each of the plurality of winding layers 1208, each of the plurality of winding turns 1212 of the winding layer is wound along a plane (e.g., a horizontal plane) of the winding layer and forms an at least substantially complete loop along the plane of the winding layer.

In various embodiments, for each of the plurality of winding layers 1208, the one or more transition portions of each of the plurality of winding turns 1212 of the winding layer include a plurality of transition portions including a first transition portion at which a corresponding coil transition of the coil occurs between the winding turn of the winding layer and one winding turn of another winding layer of the plurality of winding layers 1208. In other words, as shown in fig. 23A and 23B, each winding turn may have a plurality of transition portions at which corresponding transitions of the coil occur.

In various embodiments, the plurality of transition portions of each of the plurality of winding turns 1216 are disposed along the winding based on a predetermined pattern, such as, but not limited to, periodically positioned (e.g., regularly spaced).

In various embodiments, for each of the plurality of winding layers 1208, each of the plurality of winding turns 1212 of the winding layer includes a plurality of winding turn portions, each winding turn portion wound along a plane of the winding layer and including at least one transition portion of the plurality of transition portions. Here, the plurality of winding turn portions of the winding turn together form the winding turn along the plane of the winding layer. In other words, the winding turns of the winding layer are formed by a corresponding plurality of winding turn portions (i.e. at corresponding winding turn positions) wound along the plane of the winding layer.

In various embodiments, the coil 1204 is configured as one continuous winding.

In various embodiments, the coil 1204 forms (or constitutes) a first coil unit, and the multilayer coupler 1200 further includes one or more additional coil units connected to the first coil unit, each additional coil unit including a second coil configured for wireless power transfer based on magnetic induction technology and having a multilayer winding structure. The multi-layer winding structure includes a plurality of winding layers, each of the plurality of winding layers including a plurality of winding turns. In particular, for each of the plurality of winding layers, at least each of the plurality of intermediate winding turns of the plurality of winding turns of the winding layer comprises one or more transition portions at which a corresponding coil transition of the second coil occurs between the intermediate winding turn of the winding layer and the winding turn of another of the plurality of winding layers. In various embodiments, each additional coil unit may be configured in the same or similar (or corresponding) manner as the first coil unit (i.e., coil 1204) described in the various embodiments herein, and thus, repeated description of each additional coil unit is not required for clarity and conciseness. It will be appreciated by those skilled in the art that the present invention is not limited to any particular number of additional coil units, and that the number of additional coil units included in the multilayer coupler 1200 may be appropriately determined as desired for various purposes. Thus, in various embodiments, for each of the additional coil units and each of the plurality of winding layers described above, each of the plurality of winding turns of a winding layer of an additional coil unit comprises one or more transition portions at which a corresponding coil transition of the coil occurs between a winding turn of a winding layer of the plurality of winding layers of an additional coil unit and a winding turn of another winding layer. In various embodiments, one or more additional coil units may be connected to the first coil unit in series or in parallel.

In various embodiments, the multi-layer coupler 1200 is (or may be implemented as) a transmit coupler configured to receive a time-varying current from a power source connected thereto to generate a magnetic field to perform wireless power transfer in cooperation with a receive coupler between air gaps based on magnetic induction techniques.

In various embodiments, the multi-layer coupler 1200 is (or may be implemented as) a receive coupler configured to couple with a magnetic field generated by a transmit coupler to induce a current in the receive coupler for powering an electrical load connected to the receive coupler to perform wireless power transfer between air gaps in cooperation with the transmit coupler based on magnetic induction techniques.

Fig. 13 is a schematic diagram of a system 1300 for wireless power transfer in accordance with various embodiments of the invention. The system 1300 includes a wireless power transmitter 1320 and a wireless power receiver 1350 separated by an air gap 1352. Those skilled in the art will appreciate that the air gap may be configured as desired or as appropriate for various practical applications, such as an air gap of less than 5 mm.

In various embodiments, wireless power transmitter 1320 includes a power supply 1324 configured to generate a time-varying current; and a transmit coupler 1328 connected (electrically connected) to a power supply 1324 (e.g., configured as described above). Thus, the power supply 1324 and the transmit coupler 1328 may together form a circuit (transmitter circuit). Here, the transmit coupler 1328 is configured to receive a time-varying current from the power source 1324 for generating the magnetic field 1332 to perform wireless power transfer in cooperation with the receive coupler 1360 across the air gap 1352 based on magnetic induction technology.

In various embodiments, wireless power receiver 1350 includes an electrical load 1356; the receiving coupler 1360 (e.g., configured as described above) is connected (electrically connected) to the electrical load 1356. Thus, the receive coupler 1360 and the electrical load 1356 may together form a circuit (receiver circuit). Here, the receive coupler 1360 is configured to couple with the magnetic field 1332 generated by the transmit coupler 1328 to induce a current in the receive coupler 1360 for powering an electrical load 1356 connected to the receive coupler 1360 to perform wireless power transfer between the air gaps 1352 in coordination with the transmit coupler 1328 based on magnetic induction techniques.

In various embodiments, at least one of transmit coupler 1328 and receive coupler 1360 is a multilayer coupler 1200 according to various embodiments of the invention. In various embodiments, the transmit coupler 1328 and the receive coupler 1360 are each the multilayer coupler 1200 described in accordance with various embodiments of the invention. In various embodiments, only one of transmit coupler 1328 and receive coupler 1360 is multilayer coupler 1200 described in accordance with various embodiments of the invention.

In various embodiments, the transmit coupler 1328 and the receive coupler 1360 may be configured to have the same or similar configuration or shape in accordance with the winding strategy or technique described by the multilayer coupler 1200 of various embodiments. In various other embodiments, the transmit coupler 1328 and the receive coupler 1360 may be configured with different configurations or shapes. For example, transmit coupler 1328 and receive coupler 1360 may be configured in accordance with the winding strategy or technique described by multilayer coupler 1200 of various embodiments, but transmit coupler 1328 may be configured with a different configuration or shape than receive coupler 1360. For example, the coils of transmit coupler 1328 may have a different configuration or shape, winding turns, than the coils of receive coupler 1360, the number of winding turns of each winding layer in transmit coupler 1328 may be different than the number of winding turns of each winding layer in receive coupler 1360, and/or the number of coil units in transmit coupler 1328 may be different than the number of coil units in receive coupler 1360. For example, different combinations of configurations or shapes between the transmit and receive couplers may be selected from, but are not limited to, square, rectangular, circular, triangular, trapezoidal, hexagonal, and the like. For example, different numbers of coil units in the transmit coupler and the receive coupler may be in the range of one to five coil units, or one to two coil units, respectively.

In various embodiments, only one of the transmit coupler 1328 and the receive coupler 1360 may be configured in accordance with the multi-layer coupler 1200 described in various embodiments, and the other of the transmit coupler 1328 and the receive coupler 1360 may be configured as a conventional coupler (e.g., a conventional single-layer or multi-layer coupler).

The electrical load 1356 may be any electrical component or assembly requiring electrical power to perform an operation or function or to store electrical power/energy, such as, but not limited to, a rechargeable battery.

Those skilled in the art will appreciate that additional components or components, such as resonant capacitors, may be added to the wireless power transmitter 1320 and/or the wireless power receiver 1350 as needed or as appropriate for various purposes to form a resonant circuit configured for resonant inductive power transfer. As another example, the wireless power receiver 1350 may include a component or components (e.g., a bi-directional rectifier) configured to convert a time-varying current (AC) induced by the receiver coupler to Direct Current (DC) if the electrical load 1356 (e.g., a rechargeable battery) requires direct current.

Fig. 14 depicts a flowchart of a wireless power transfer method 1400 in accordance with various embodiments of the invention. The method 1400 includes: at 1402, a time-varying current is generated by a power source 1324 at a wireless power transmitter 1320; at 1404, a time-varying current from the power source 1324 is received by a transmit coupler 1328 at a wireless power transmitter 1320 connected to the power source 1324 for generating a magnetic field 1332 to perform wireless power transfer based on magnetic induction techniques with a receive coupler 1360 across the air gap 1352; at 1406, a magnetic field 1332 generated from the transmit coupler 1328 is coupled by a receive coupler 1360 at a wireless power receiver 1350 connected to an electrical load 1356 to induce a current in the receive coupler 1360 to perform wireless power transfer between the air gaps 1352 in cooperation with the transmit coupler 1328 based on magnetic induction techniques; at 1408, power is supplied by a receive coupler 1360 at the wireless power receiver 1350 to an electrical load 1356 connected thereto based on current induced therein. Specifically, as described above, at least one of receive coupler 1360 and transmit coupler 1328 is a multilayer coupler 1200 according to various embodiments of the invention. Also as described above, the wireless power transmitter 1320 and the wireless power receiver 1350 are separated by an air gap 1352.

Fig. 15 depicts a flow chart of a method 1500 of manufacturing a multi-layer coupler for wireless power transfer, such as multi-layer coupler 1200 described in accordance with various embodiments of the invention, in accordance with various embodiments of the invention. At 1502, method 1500 includes configuring a coil 1204 for wireless power transfer based on magnetic induction technology, the coil 1204 having a multi-layer winding structure. The multi-layer winding structure includes a plurality of winding layers 1208, each winding layer of the plurality of winding layers 1208 including a plurality of winding turns 1212. Specifically, for each of the plurality of winding layers 1208, at least each of the plurality of intermediate winding turns of the plurality of winding turns 1212 of the winding layer includes one or more transition portions 1216 at which transition portions 1216 a corresponding coil transition of the coil occurs between an intermediate winding turn of the winding layer of the plurality of winding layers 1208 and a winding turn of another winding layer.

In various embodiments, the method 1500 is used to fabricate the multi-layer coupler 1200 described in accordance with various embodiments of the invention, thus, various aspects or steps of the method 1500 may correspond to various aspects or features of the multi-layer coupler 1200 described herein, and thus, repeated description of the method 1500 is not necessary for clarity and conciseness. In other words, the various embodiments described herein in the context of multilayer coupler 1200 are similarly valid for method 1500, and vice versa. In various embodiments, the coil 1204 may be formed on a substrate made of a non-conductive material, such as, but not limited to, non-metallic epoxy, plastic-like Acrylonitrile Butadiene Styrene (ABS), acrylic, nylon, and the like.

Further, based on prior art known in the art, a coil (e.g., a wire or a set/bundle of wires) may be formed in a configuration or shape as described in accordance with various embodiments herein (e.g., as described in fig. 12A or 12B herein). For example, the coil (continuous winding) may be placed on a substrate (e.g., a mold or housing) made of a non-conductive material. The substrate may include one or more rails (or grooves) configured/shaped to receive the coils (placed therein along the rails) to form/configure the coils into a desired shape or configuration. In other words, the track may be configured/shaped in the substrate according to a desired coil shape or configuration, and then the coil is configured (wound) into the desired shape/configuration described in accordance with various embodiments of the present invention by laying/placing the coil along the track. For example, tracks (or grooves) may be formed on both sides of the substrate to create a double layer structure. Multiple substrates with respective tracks (or grooves) may also be stacked to form a coil with a multi-layer wound structure. As another example, the casting may be configured/designed similar to the substrate with rails (or grooves) described above to accommodate or secure the wires in a desired shape or configuration prior to being encapsulated in the epoxy. Once the epoxy is hardened and the coil shape is fixed, the casting may be removed. As a further example, the casting may also remain as a support structure. As yet another example, a multi-layer Printed Circuit Board (PCB) may be used to form conductive windings of a desired coil shape or configuration to form winding turns.

It is to be understood by persons skilled in the art that the terminology used herein is for the purpose of describing various embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Moreover, any reference herein to a component or feature using a name such as "first," "second," etc. does not limit the number or order of such components or features unless otherwise indicated or the context requires otherwise. For example, such designations are used herein as a convenient way to distinguish between two or more components or instances of a component. Thus, references to first and second elements do not mean that only two elements can be employed, or that the first element must precede the second element. In addition, a phrase referring to "at least one of" refers to any single item therein or any combination of two or more items therein.

In order that the invention may be readily understood and put into practical effect, various embodiments of the invention will be described hereinafter by way of example only and not by way of limitation. However, those skilled in the art will appreciate that the present invention may be embodied in a variety of different forms or arrangements and should not be construed as limited to the embodiments set forth below. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In particular, for a better understanding of the invention and without limitation or loss of generality, various embodiments of the invention will now be described in a multi-layer winding structure, unless otherwise indicated, wherein each of the plurality of winding turns of each winding layer comprises one or more transition portions at which a corresponding inter-layer coil transition of the coil occurs. However, it should be understood by those skilled in the art that the present invention is not so limited, as long as at least each of the plurality of intermediate winding turns in the plurality of winding turns of each winding layer includes one or more transition portions at which a corresponding inter-layer coil transition of the coil occurs.

According to various embodiments, a multilayer coupler is provided, including a coil having a multilayer winding structure (e.g., based on a winding strategy (or technique) or sequence) configured in accordance with various embodiments of the invention. In various embodiments, coils configured to have such a multi-layer wound structure may have a serpentine shape (e.g., a general "S" shape) in the transverse direction (or radial direction), and thus may be referred to as serpentine coils (e.g., an "S" coil (or S coil)).

Fig. 16 is a schematic cross-sectional view of a cross-section of a first example multilayer coupler 1600, and an associated first winding sequence (based on winding turns or loops) for forming a multilayer winding structure of a coil thereof, shown or indicated by arrow 1610, in accordance with various embodiments of the invention. The first example multilayer coupler 1600 includes a coil 1604 configured for wireless power transfer based on magnetic induction technology and has a multilayer winding structure including a plurality of winding layers 1608, each of the plurality of winding layers 1608 including a plurality of winding turns 1612.

In a first winding sequence associated with the first example multilayer coupler 1600, as shown in fig. 16, the coil 1604 is wound (e.g., a second side or end corresponding to an innermost or outermost winding turn (as opposed to the first side or end)) from one side or end of the first example multilayer coupler (e.g., a first side or end corresponding to an innermost or outermost winding turn (as opposed to the first side or end) relative to a center or core of the first example multilayer coupler 1600). While transitioning across multiple winding layers (i.e., inter-layer coil transitions) at each winding turn position of the first example multilayer coupler 1600. In various embodiments, the plurality of winding turns of each of the plurality of winding layers may collectively form a plurality of axial winding turn groups, each axial winding turn group including winding turns at a same winding turn location (e.g., a first axial winding turn group at winding turn location 1 and a second axial winding turn group at winding turn location 2, etc.). Here, according to a first winding sequence, the coil 1604 may be configured to span multiple winding turns within a first axial set of winding turns (e.g., one winding turn to another winding turn, up to a last (or final) winding turn, thus across multiple winding layers) (e.g., at a first winding turn position), and then transition to a next axial winding turn set (i.e., at a next winding turn position). Upon completing the transition in the first axial winding turn group, the coil 1604 may be configured to transition across multiple winding turns within the second axial winding turn group (e.g., one winding turn to another winding turn, up to the last winding turn, and thus across multiple winding layers), and so on, up to the last (or final) axial winding turn group, where the coil 1604 may be configured to transition across multiple winding turns. Accordingly, as shown in fig. 16, the coil 1604 configured to have the above-described multi-layer wound structure has a serpentine shape (or more specifically, an "S" shape) in the lateral direction, and thus may be referred to as a serpentine coil (or more specifically, an "S" coil or an S coil).

Thus, for each of the plurality of winding layers 1608, each of the plurality of winding turns 1612 of the winding layer includes a transition portion at which a corresponding coil transition of the coil 1604 occurs between the winding turn of the winding layer and the winding turn of another of the plurality of winding layers 1608. Specifically, in each of the plurality of axial winding turn groups, for each winding turn except for the last winding turn in the axial winding turn group, the winding turn includes a transition portion (e.g., corresponding to the first transition portion as described above in accordance with various embodiments) at which a coil transition of the coil 1604 occurs between the winding turn in the axial winding turn group and another winding turn, and in various embodiments from a winding turn in the axial winding turn group to an immediately adjacent winding turn (e.g., at winding turn position 1 from layer 1 to layer 2 relative to the axial winding turn group).

In addition, for each pair of immediately adjacent axial winding turn groups of the plurality of axial winding turn groups (e.g., a pair of axial winding turn groups at winding turn position 1 and winding turn position 2, a pair of axial winding turn groups at winding turn position 2 and winding turn position 3, etc.), in accordance with the first winding order, in a first axial winding turn group of the pair of axial winding turn groups (e.g., an axial winding turn group at winding turn position 1 and winding turn position 1 of a pair of axial winding turn groups at winding turn position 2, for each group of turns of the axial group winding groups except for the last group winding turn, at a first transition portion of the winding turn, the corresponding coil transition of the coil 1604 occurs in a first transition direction 1616 from winding turn to an immediately adjacent winding turn in the axial winding turn group, and in a second axial winding turn group of the pair of axial winding turn groups (e.g., at winding turn position 2 of the axial winding turn group for a pair of axial winding turn groups at winding turn position 1 and winding turn position 2), the corresponding coil transition of the coil 1604 occurs in a second transition direction 1618 from winding turn to an immediately adjacent winding turn in the axial winding turn group for each winding turn except for a last winding turn in the axial winding turn group at a first transition portion of the winding turns. Here, as shown in fig. 16, the first transition direction 1616 and the second transition direction 1618 are opposite in direction.

Further, according to the first winding sequence, the last winding turn of the first axial winding turn group (e.g., the axial winding turn group at winding turn position 1 of the pair of axial winding turn groups at winding turn position 1 and winding turn position 2) includes a second transition portion at which the coil transitions to the first winding turn of the second axial winding turn group (e.g., the axial winding turn group at winding turn position 2 of the pair of axial winding turn groups at winding turn position 1 and winding turn position 2), the coil transitions of which are shown by arrows 1622 in fig. 16. Thus, in various embodiments, the first and last winding turns of the axial winding turn group may be defined with respect to a coil transition direction across winding turns in the axial winding turn group, or in other words, with respect to a position of a beginning (corresponding to the first winding turn) and an ending (corresponding to the last winding turn) of a coil transition across winding turns within the axial winding turn group.

By way of example only and not limitation, fig. 17A-17C are simplified schematic diagrams of rectangular multi-layer couplers, each including a coil configured with a multi-layer winding structure according to a first winding order, according to various embodiments of the invention. In particular, fig. 17A is a simplified schematic diagram of a rectangular two-layer coupler 1704, the rectangular two-layer coupler 1704 including a coil 1706 configured to have a multi-layer winding structure according to a first winding order. Fig. 17B is a simplified schematic diagram of a rectangular tri-layer coupler 1714, the rectangular tri-layer coupler 1714 including a coil 1716 configured with a multi-layer winding structure according to a first winding order. Fig. 17C is a simplified schematic diagram of a rectangular four-layer coupler 1724, the rectangular four-layer coupler 1724 including a coil 1726 configured with a multi-layer winding structure according to a first winding order. Thus, it will be appreciated by those skilled in the art that the multi-layer winding structure configured according to the first winding sequence may suitably include any number of the plurality of winding layers as desired, and the multi-layer winding structure is not limited to any particular number of the plurality of winding layers. Furthermore, it will be appreciated by those skilled in the art that the multi-layer winding structure configured according to the first winding sequence may suitably include any number of winding turns per winding layer as desired, and that the multi-layer winding structure is not limited to any particular number of winding turns per winding layer.

Fig. 18 is a schematic cross-sectional view of a portion of various multilayer couplers according to various embodiments of the invention, and a winding sequence of a multilayer winding structure for forming a coil shown or indicated by an arrow. In particular, fig. 18 also shows that the coil of the multilayer coupler may include a plurality of coil portions (e.g., dashed boxes in fig. 18), and one or more of the plurality of coil portions may be configured to have a multilayer winding structure according to the first winding order, and the other one or more of the plurality of coil portions may be configured as appropriate according to other winding orders (e.g., a conventional single-layer winding order or also according to the first winding order) as needed. As an example, the three-layer coupler 1714 shown in fig. 18 may include two coil portions, in other words, a first coil portion 1718 configured to have a multi-layer winding structure according to a first winding order and a second coil portion 1720 configured according to a conventional single-layer winding order, as shown in fig. 18, whereby the first coil portion 1718 is converted into the second coil portion 1720. As another example, the four-layer coupler 1724 shown in fig. 18 may include two coil portions, in other words, as shown in fig. 18, a first coil portion 1728 configured to have a multi-layer winding structure according to a first winding order and a second coil portion 1730 also configured to have a multi-layer winding structure according to the first winding order (but in an opposite direction or manner as compared to the first coil portion 1728), whereby the first coil portion 1728 transitions to the second coil portion 1730. Fig. 18 also shows a further example of a four-layer coupler 1724, the four-layer coupler 1724 having a first coil portion configured to have a multi-layer winding structure according to a first winding order and a second coil portion configured according to other winding orders or also according to the first winding order.

Fig. 19 is a schematic cross-sectional view of a cross-section of a second exemplary multilayer coupler 1900 according to various embodiments of the invention, and a second winding sequence (based on winding turns or loops) for forming a multilayer winding structure of its coil, as indicated by the arrows. The second example multilayer coupler 1900 may be the same as or similar to the first example multilayer coupler 1600 except that the multilayer winding structure of the coils thereof is configured according to a second winding order. Thus, the second example multilayer coupler 1900 includes a coil 1904 configured for wireless power transmission based on magnetic induction technology and has a multilayer winding structure including a plurality of winding layers 1908, each winding layer of the plurality of winding layers 1908 including a plurality of winding turns 1912.

In a second winding sequence of the second example multilayer coupler 1900, as shown in fig. 19, the coil 1904 is wound (e.g., a second side or a second end corresponding to an outermost or an innermost winding turn (as opposed to a first side or a first end) relative to a center or a core of the second example multilayer coupler 1900) from one side or end (e.g., a first side or a first end corresponding to an innermost or an outermost winding turn (as opposed to a first side or a first end) of the second example multilayer coupler 1900). While transitioning across multiple winding layers (i.e., inter-layer coil transitions) at each winding turn position of the second example multilayer coupler 1900. Similar to the first example multilayer coupler 1600, in various embodiments, the plurality of winding turns of each of the plurality of winding layers may collectively form a plurality of axial winding turn groups, each axial winding turn group including winding turns at the same winding turn position relative to the corresponding winding layer (e.g., a first axial winding turn group at winding turn position 1, a second axial winding turn group at winding turn position 2, and so on). Here, according to a second winding order, the coil 1904 may be configured to span multiple winding turns within the first axial winding turn group (e.g., one winding turn to another winding turn, and thus across multiple winding layers) (e.g., at winding turn position 1), then transition to the axial winding turn group of the next winding turn position (i.e., at the next winding turn position (or winding turn position 2)), upon completion of the transition in the first axial winding turn group, the coil 1904 may then be configured to span multiple winding turns within the second axial winding turn group (e.g., one winding turn to another winding turn, and thus across multiple winding layers), and so on, until the last axial winding turn group, wherein the coil 1904 may be configured to span multiple winding turns at the last axial winding turn group (e.g., one winding turn to another winding turn, and thus across multiple winding layers). Accordingly, as shown in fig. 19, the coil 1904 configured to have the above-described multilayer winding structure has a serpentine shape (or more specifically, a "Z" shape) in the transverse direction, and thus may be referred to as a serpentine coil (more specifically, a "Z" coil (or Z coil)).

Thus, for each of the plurality of winding layers 1908, each of the plurality of winding turns 1912 of the winding layer includes a transition portion at which a corresponding coil transition of the coil 1904 occurs between the winding turn of the winding layer and the winding turn of another of the plurality of winding layers 1908. Specifically, in each of the plurality of axial winding turn groups, for each winding turn except for the last winding turn in the axial winding turn group, the winding turn includes a transition portion at which a corresponding coil transition of coil 1904 occurs between the winding turn in the axial winding turn group and another winding turn, and in various embodiments, transitions from the winding turn to an immediately adjacent winding turn in the axial winding turn group (e.g., at winding turn position 1 from layer 1 to layer 2 in the axial winding turn group).

In addition, in accordance with the second winding sequence, for each pair of adjacent axial winding turn groups of the plurality of axial winding turn groups (e.g., a pair of axial winding turn groups at winding turn position 1 and winding turn position 2, a pair of axial winding turn groups at winding turn position 2 and winding turn position 3, etc.), in a first axial winding turn group of the pair of winding turn positions (e.g., an axial winding group of winding turn position 1 for a pair of axial winding turn groups at winding turn position 1 and winding turn position 2), for each winding turn of the axial winding turn group other than the last winding turn, a corresponding coil transition of the coil occurs in a first transition direction 1916 between winding turns of the pair of axial winding turn groups from winding turns to immediately adjacent winding turns, and in a second axial winding turn group of the pair of winding turns (e.g., an axial winding group of winding turns position 2 for winding turn position 1 and winding turn position 2), for each winding turn of the pair of axial winding turn groups other than the last winding turn in the first transition direction 1916 occurs in a second transition direction 1918 between corresponding turns of the pair of winding turns of the winding turns in the pair of winding turns immediately adjacent to the first transition direction as shown.

Further, according to the second winding sequence, the last winding turn of the first axial winding turn group (e.g., for the axial winding turn group of the pair of axial winding turn groups at winding turn position 1 and winding turn position 2) includes a second transition portion where the coil transitions to the first winding turn of the second axial winding turn group (e.g., for the axial winding turn group of the pair of axial winding turn groups at winding turn position 1 and winding turn position 2), as indicated by the coil transition shown by arrow 1922 in fig. 19. Thus, in various embodiments, the first and last winding turns of the axial winding turn group may be relative to the direction of the coil transition across the winding turns in the axial winding turn group, or in other words, relative to the location of the beginning (corresponding to the first winding turn) and ending (corresponding to the last winding turn) of the coil transition across the winding turns within the axial winding turn group.

By way of example only and not limitation, fig. 20A-20C are simplified schematic diagrams of rectangular multi-layer couplers, each including a coil configured as a multi-layer winding structure having a second winding order, according to various embodiments of the invention. In particular, fig. 20A is a simplified schematic diagram of a rectangular double-layer coupler 2004, the rectangular double-layer coupler 2004 including a coil 2006 configured as a multi-layer winding structure having a second winding sequence. Fig. 20B is a simplified schematic diagram of a perspective view of a rectangular two-layer coupler 2004. Fig. 20C is a simplified schematic diagram of a rectangular tri-layer coupler 2014, the coupler 2014 including a coil 2016 configured as a multi-layer winding structure having a second winding sequence. Thus, it will be appreciated by those skilled in the art that the multi-layer winding structure configured according to the second winding sequence may suitably include any number of the plurality of winding layers as desired, and the multi-layer winding structure is not limited to any particular number of the plurality of winding layers. Furthermore, it will be further understood by those skilled in the art that the multi-layer winding structure configured according to the second winding sequence may suitably include any number of winding turns per winding layer as desired, and the multi-layer winding structure is not limited to any particular number of winding turns per winding layer.

Fig. 21 is a schematic cross-sectional view of a portion of various multilayer couplers according to various embodiments of the invention, and a winding sequence of a multilayer winding structure for forming a coil thereof shown or indicated by an arrow. In particular, similar to fig. 18, fig. 21 shows that the coil of the multilayer coupler may include a plurality of coil portions (indicated by a dotted line box in fig. 21), and one or more of the plurality of coil portions may be configured as a multilayer winding structure having a second winding order, and the other one or more of the plurality of coil portions may be configured as appropriate according to other winding orders (e.g., a conventional one-layer winding order) or also according to the second winding order, as needed. As an example, the three-layer coupler 2014 shown in fig. 21 may include two coil portions, in other words, as shown in fig. 21, a first coil portion 2018 configured to have a multi-layer winding structure according to a second winding order and a second coil portion 2020 configured according to a conventional single-layer winding order, whereby the first coil portion 2018 transitions to the second coil portion 2020. As another example, the four-layer coupler 2024 shown in fig. 21 may include two coil portions, in other words, as shown in fig. 21, a first coil portion 2028 configured to have a multi-layer winding structure according to a second winding order and a second coil portion 2030 also configured to have a multi-layer winding structure according to a second winding order (but in an opposite direction or manner as compared to the first coil portion 2028), whereby the first portion 2028 transitions to the second portion 2030. Another example of a four-layer coupler 2024 having a first coil portion and a second coil portion, each configured with a multi-layer winding structure according to a second winding order, whereby the first coil portion 2028 transitions to the second coil portion 2030 in a different manner.

Fig. 22 is a partial cross-sectional view of a third exemplary multilayer coupler 2200 in accordance with various embodiments of the present invention, and a third winding sequence (based on winding turns or loops) for forming a multilayer winding structure of the coil shown or indicated by the arrows. The third example multilayer coupler 2200 may be the same as or similar to the first example multilayer coupler or the second example multilayer coupler except that the multilayer winding structure of the coil thereof is configured according to the third winding order. Thus, the third example multilayer coupler 2200 includes a coil 2204 configured for wireless power transfer based on magnetic induction technology and has a multilayer winding structure comprising a plurality of winding layers, each of the plurality of winding layers comprising a plurality of winding turns.

In a third winding sequence of the third example multilayer coupler 2200, as shown in fig. 22, the coil 2204 is wound (e.g., a second side or a second end, such as an outermost or an innermost winding turn (as opposed to the first side or the first end)) from one side or end of the third example multilayer coupler (e.g., a first side or a first end, such as an innermost or an outermost winding turn corresponding to a center or core of the third example multilayer coupler 2200). While transitioning across multiple winding layers (i.e., an inter-layer coil transition) at least each of the plurality of intermediate winding turns in the plurality of winding turns. In particular, according to the third winding order, the coil 2204 may not be configured to transition to another winding layer at all winding turns of the winding layer, but rather to transition to another winding layer at least a plurality of intermediate winding turns of the winding layer. In other words, according to the third winding order, the inter-layer coil transition at one or more intermediate winding turns at a winding layer may be skipped (may not occur) and may simply transition to another winding turn at the same winding layer. For example, a plurality of intermediate winding turns at which inter-layer coil transitions occur may be periodically located at the winding layers, e.g., based on a predetermined pattern. For example, when a coil transitions from another winding layer to a winding turn at a winding layer (e.g., at winding turn position 1), the next intermediate winding turn at the winding layer at which the interlayer coil transition occurs may be located two or more winding turn positions (e.g., at winding turn position 2 or at winding turn position 3) away from the winding turn. Thus, the predetermined pattern may be a predetermined number of winding turns. By way of example and not limitation, as shown in fig. 22, when a coil transitions from another winding layer (e.g., layer 1) to a first winding turn (e.g., at winding turn position 1) at a winding layer (e.g., layer 2), the coil transition from the first winding turn may continue to a second winding turn (e.g., immediately subsequent winding turn(s) at the same winding layer (e.g., layer 2), and further transition from the second winding turn to a third winding turn (e.g., at winding turn position 3) at the same winding layer, then transition at the third winding turn to winding turn position 2 at another winding layer (e.g., layer 2), and so on, until the last remaining winding turn (e.g., the innermost winding turn). Thus, in case the predetermined winding turn position is 2, the inter-layer coil transition of the second winding turn of the winding layer may be skipped. Further, as shown in fig. 22, one or more inter-layer transitions may be made between winding turns at different winding turn positions (or groups of different axial winding turns).

By way of example only and not limitation, fig. 22 further depicts a simplified schematic diagram of a third example multilayer coupler 2200 of a rectangular multilayer coupler including a coil 2204 configured as a multilayer winding structure having a third winding order of various embodiments of the invention, in accordance with various embodiments of the invention. In particular, fig. 22 depicts a simplified schematic of a rectangular double-layer coupler 2200, the rectangular double-layer coupler 2200 comprising a coil 2204 configured as a multi-layer winding structure having a third winding order. Similarly, it will be appreciated by those skilled in the art that the multi-layer winding structure of the third winding sequence configuration may suitably include any number of the plurality of winding layers as desired, and the multi-layer winding structure is not limited to any particular number of the plurality of winding layers. Further, it will be appreciated by those skilled in the art that the multi-layer winding structure of the third wire-wound sequential configuration may suitably include any number of winding turns in each winding layer as desired, and the multi-layer winding structure is not limited to any particular number of winding turns in each winding layer.

In various embodiments, the multilayer couplers of the various embodiments of the invention as described above may include one transition portion (e.g., corresponding to the first transition portion of the various embodiments described above) in each winding turn, as shown in fig. 17A-17C and 20A-20C. In various embodiments, in each of the plurality of axial winding turn groups, one transition portion of each winding turn in the axial winding turn group is at least substantially aligned with respect to the axial direction, as shown in fig. 17A-17C and 20A-20C. Furthermore, in each of the plurality of winding layers, one transition portion of each winding turn in the winding layer is at least substantially aligned with respect to the transverse direction, as also shown in fig. 17A to 17C and 20A to 20C. By way of example and not limitation, in the case where the coil has a rectangular shape, as shown in fig. 17A to 17C and 20A to 20C, one transition portion may be located or positioned at a side (e.g., top side) middle portion of the coil.

In various embodiments, the multilayer coupler may include multiple transition portions for each winding turn. That is, for each of the plurality of winding layers, each of the plurality of winding turns of the winding layer includes a plurality of transition portions at which a corresponding coil transition of the coil occurs between the winding turn of the winding layer and the winding turn of another of the plurality of winding layers. In various embodiments, the plurality of transition portions of each of the plurality of winding turns may be periodically disposed along the winding turns based on a predetermined pattern.

By way of example only and not limitation, fig. 23A and 23B are simplified schematic illustrations of rectangular multi-layer couplers in various embodiments of the invention, each rectangular multi-layer coupler including a coil configured as a multi-layer winding structure having a second winding sequence, wherein each winding turn has a plurality of transition portions. In particular, fig. 23A is a simplified schematic diagram of a rectangular double-layer coupler 2304, the rectangular double-layer coupler 2304 including a coil 2306 configured as a multi-layer winding structure having a second winding sequence, whereby each winding turn provides two transition portions. Fig. 23B is a simplified schematic diagram of a rectangular double-layer coupler 2314, the rectangular double-layer coupler 2314 including a coil 2316 configured as a multi-layer winding structure having a second winding sequence, whereby each winding turn provides four transition sections. Accordingly, as shown in fig. 23A and 23B, a plurality of transition portions of each of the plurality of winding turns may be disposed along the winding turns based on a predetermined pattern. For example, a plurality of transition portions may be periodically disposed along the winding turns. In various embodiments, for each of the plurality of winding layers, each of the plurality of winding turns of the winding layer includes a plurality of winding turn portions, each winding turn portion wound along a winding layer plane and including one transition portion of at least a plurality of transition portions. Thus, the plurality of winding turn portions of the winding turn collectively form the winding turn along the winding layer plane. It will be appreciated by those skilled in the art that the multi-layer winding structure is not limited to any particular number of transition portions per winding turn, and that any number of transition portions may be provided for each winding turn as appropriate. Furthermore, one skilled in the art will appreciate that the location of the one or more transition portions at each winding turn is not limited to any particular location along the winding turn, and their location may be suitably set as desired.

Thus, it should be understood by those skilled in the art that the multi-layer winding structure according to various embodiments of the present invention is not limited to any particular number of winding turns, winding layers, transitions of each winding turn, and locations of transitions at the winding turns.

The multilayer winding structure utilizing various embodiments of the present invention advantageously improves the distribution of parasitic components and thus improves the impedance characteristics of the coil at different frequencies. For example, the impedance is higher at frequencies higher than the desired frequency. As a result, it has been found that the multi-layer winding structure of various embodiments of the present invention can significantly reduce electromagnetic noise emissions in the conduction and radiation paths while achieving the same or better wireless power transfer performance at the intended operating frequency.

Accordingly, various embodiments of the present invention provide methods and structures for multilayer windings that can significantly improve the impedance characteristics of multilayer couplers and reduce electromagnetic noise emissions (in both conductive and radiative paths). As a result, the multilayer coupler may advantageously have a higher potential to meet certain electromagnetic compatibility regulatory restrictions when applied as a product. In addition, the invention can reduce the extra electromagnetic filter and clamp, thereby reducing the cost and weight.

Thus, the multi-layer winding structure may advantageously be configured to redistribute parasitic capacitance between different lengths of wire spanning different winding layers.

In sharp contrast, in existing multilayer structures (e.g., based on the first and second conventional winding sequence configurations described above), it can be seen that the coupler is configured with different coils located in different layers, each connected in series, as shown in fig. 24, with the dashed boxes representing the individual coil assemblies. Thus, as can be seen in fig. 24, in each winding layer, long winding turns may form a coil. Fig. 25 is a perspective schematic view of a conventional multilayer coupler 2500 of a first conventional winding sequence configuration, further illustrating the formation of parasitic capacitance between coils in adjacent winding layers. Various embodiments find that adjacent winding layers create multiple resonance points in the impedance characteristics, resulting in multiple low impedance paths where electromagnetic noise is prone to propagation/radiation.

As a distinct contrast, and without wishing to be bound by theory, based on the multi-layer winding structure of the various embodiments, parasitic capacitance may be advantageously redistributed by stretching the structure of the wires between different layers. In this way, the windings are truly distributed over different layers rather than effectively having unique coils per layer in accordance with the conventional multilayer coupler 2500. As a result, the effective parasitic capacitance is smaller, thus moving the low impedance resonance point to a higher frequency, and the electromagnetic noise generated is significantly smaller (away from the fundamental).

As previously mentioned, it will be appreciated by those skilled in the art that the multi-layer winding structure or coil is not limited to any particular shape and may be any suitable shape, such as rectangular, circular, hexagonal, etc. Furthermore, one or more different winding layers of the multi-layer winding structure may also have different coil shapes. For example, the coil may be formed from any type of wire or combination thereof (e.g., single round wire, flat wire, enameled wire, wire harness, litz wire, PCB trace, etc.). Furthermore, each winding layer may have a different number of winding turns, a different number of transition portions, and/or different transition positions.

In various embodiments, a coil configured to have a multi-layer winding structure as described above may form a coil unit (e.g., a first coil unit). Here, the multi-layer coupler may further include one or more additional coil units connected to the first coil unit, each additional coil unit including a second coil configured for wireless power transmission based on a magnetic induction technology and having a multi-layer winding structure. The multi-layer winding structure includes a plurality of winding layers, each of the plurality of winding layers including a plurality of winding turns. In particular, similarly, for each of the plurality of winding layers, each of the plurality of winding turns of the winding layer comprises one or more transition portions at which a corresponding coil transition of the second coil occurs between an intermediate winding turn of the winding layer and a winding turn of another of the plurality of winding layers. In other words, each additional coil unit may be configured according to the first, second, or third winding order as described in the above various embodiments.

For illustrative purposes only, fig. 26A-26C are simplified schematic diagrams of a rectangular multilayer coupler including a plurality of coil units. In particular, fig. 26A is a simplified schematic diagram of a rectangular multi-layer coupler 2604, the rectangular multi-layer coupler 2604 including three coil unit stacks (at least partially stacked on one another) to form additional coil unit layers and connected independently of one another. Fig. 26B is a schematic diagram of a simplified rectangular multi-layer coupler 2614 including three coil unit stacks (at least partially stacked on each other) to form additional coil unit layers and connected in series. Fig. 26C is a schematic diagram of a simplified rectangular multi-layer coupler 2624 that includes three coil unit stacks (e.g., at least partially stacked on one another) to form additional coil unit layers and connected in parallel.

In general, the multilayer coupler of the various embodiments may be applied to any application that utilizes Alternating Current (AC) flowing in a coil to generate an electromagnetic flux as a transmission power. In particular, for example, the multilayer coupler generates alternating current in the coil independent of the electronic topology, so it can be applied to, but is not limited to, purely inductive wireless power transfer (e.g., in a gap transformer or the like) and resonant wireless power transfer. The multilayer coupler is also not limited to any particular compensation topology, such as series-series, series-parallel, parallel-series, parallel-parallel, or combinations thereof (e.g., LCL, LCC, CCL, etc.). The multi-layer coupler may also be suitable for all power ratings from low power applications (e.g., phones, cameras, and sensors) to higher power applications (e.g., robots, automated guided vehicles, and electric vehicles). Furthermore, the multilayer coupler is not limited to wireless power applications, but may also be used, for example, for induction heating, more specifically, for example, for heating coils in induction cookware, as power is still transmitted wirelessly from the induction heating assembly to the object being heated.

As an example of performance comparison, fig. 27A and 27B show alternating current measurement results (AC current waveforms) in the multilayer coupler configured according to the second winding order and the conventional multilayer coupler configured according to the first conventional winding order in various embodiments. In addition to the differences in the magnetic couplers themselves, fig. 27A and 27B illustrate that electromagnetic noise emissions are significantly lower in the multi-layer couplers of the various embodiments configured according to the second winding order, thereby demonstrating significant advantages or technical effects of the multi-layer couplers of the various embodiments over conventional multi-layer couplers.

Finally, it is noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the present invention, which is intended to be covered by the claims of the present invention.

Claims

1. A multilayer coupler for wireless power transmission, characterized in that the multilayer coupler comprises one coil for wireless power transmission based on magnetic induction technology and having a multilayer winding structure; the multi-layer winding structure comprises a plurality of winding layers, wherein each winding layer comprises a plurality of winding turns; for each of the plurality of winding layers, a plurality of intermediate winding turns of the plurality of winding turns in the winding layer include one or more transition portions at locations where a corresponding coil transition of the coil occurs between the intermediate winding turn of the winding layer and a winding turn of another winding layer.

2. The multilayer coupler of claim 1, wherein for each of the plurality of winding layers, each winding turn of the plurality of winding turns in the winding layer includes one or more transition portions at a location where a corresponding coil transition of the coil occurs between the winding turn of the winding layer and a winding turn of another winding layer in the plurality of winding layers.

3. The multilayer coupler of claim 1, wherein for each of the plurality of winding layers and each of the plurality of intermediate winding turns in the winding layer, the intermediate winding turn of the winding layer and the winding turn of the other winding layer are the same in winding turn position at a location where a corresponding coil transition of the coil occurs between the intermediate winding turn of the winding layer and the winding turn of the other winding layer.

4. The multilayer coupler of claim 1, wherein for each of the plurality of winding layers and one or more of the plurality of intermediate winding turns in the winding layer, the intermediate winding turn of the winding layer and the winding turn of the other winding layer differ in winding turn position where a corresponding coil transition of the coil occurs between the intermediate winding turn of the winding layer and the winding turn of the other winding layer.

5. The multilayer coupler of claim 2, wherein the plurality of winding turns of each of the plurality of winding layers collectively form a plurality of axial winding turn groups, each axial winding turn group comprising winding turns located at the same winding turn location.

6. The multilayer coupler of claim 5 wherein, in each axial winding turn set of the plurality of axial winding turn sets, for each axial winding turn of the axial winding turn set other than the last axial winding turn, a winding turn comprises a first transition portion of the one or more transition portions at a location in the axial winding turn set where a corresponding coil transition of the coil occurs between the winding turn and the other winding turn.

7. The multilayer coupler of claim 6 wherein, for each winding turn in the axial winding turn set other than the last winding turn, at a first transition portion of the winding turn, a corresponding coil transition of the coil occurs from the winding turn to an immediately adjacent winding turn in the axial winding turn set.

8. The multilayer coupler of claim 7 wherein,

for each pair of immediately adjacent axial winding turn groups of the plurality of axial winding turn groups, in a first axial winding turn group of the pair, for each winding turn other than a last winding turn of the axial winding turn group, a corresponding coil transition of the coil occurs in the axial winding turn group from winding turn to immediately adjacent winding turn along a first transition direction, and in a second axial winding turn group of the pair, for each winding turn other than the last winding turn of the axial winding turn group, at the first transition portion of the winding turn, a corresponding coil transition of the coil occurs in the axial winding turn group from winding turn to immediately adjacent winding turn along a second transition direction, and the first transition direction and the second transition direction are opposite.

9. The multilayer coupler of claim 7 wherein

For each pair of immediately adjacent axial winding turn groups of the plurality of axial winding turn groups, in a first axial winding turn group of the pair, for each winding turn of the axial winding turn group other than the last winding turn, a corresponding coil transition of the coil occurs in the axial winding turn group from winding turn to immediately adjacent winding turn along a first transition direction at a first transition portion of the winding turns, and in a second axial winding turn group of the pair, for each winding turn of the pair other than the last winding turn of the axial winding turn group, a corresponding coil transition of the coil occurs in the axial winding turn group from winding turn to immediately adjacent winding turn along the first transition direction at the first transition portion of the winding turns.

10. The multilayer coupler of claim 8 or claim 9, wherein,

the last winding turn in the first axial winding turn group comprises a second transition portion at which the coil transitions to the first winding turn in the second axial winding turn group, and

the first winding turn and the last turn winding in the second axial winding turn set are located at opposite ends of the second axial winding turn set.

11. The multilayer coupler of any one of claims 6 to 10 wherein, in each of the plurality of axial winding turn groups, the first transition portion of each winding turn in the axial winding turn group is at least substantially aligned with the axial direction.

12. The multilayer coupler of claim 11 wherein in each of the plurality of winding layers, the first transition portion of each winding turn in the winding layer is at least substantially aligned with the transverse direction.

13. A multilayer coupler according to any one of claims 6 to 12, wherein, for each of the plurality of winding layers, each winding turn of the plurality of winding turns in the winding layer is wound along a plane of the winding layer and forms a complete loop at least substantially along the plane of the winding layer.

14. The multilayer coupler of any one of claim 6 to claim 12, wherein, for each of the plurality of winding layers, the one or more transition portions within each of the plurality of winding turns in the winding layer comprise a plurality of transition portions,

it comprises a first transition portion at which a corresponding coil transition of the coil occurs between a winding turn of a winding layer of the plurality of winding layers and a winding turn of another winding layer.

15. The multilayer coupler of claim 14 wherein the plurality of transition portions of each of the plurality of winding turns are positioned along the winding turns based on a predetermined pattern.

16. The multilayer coupler of claim 14 or claim 15 wherein,

for each of the plurality of winding layers, each winding turn of the plurality of winding turns in the winding layer includes a plurality of winding turn portions, each winding turn portion is wound along a plane of the winding layer and includes at least one transition portion of the plurality of transition portions, and the plurality of winding turn portions of the winding turns collectively form a winding turn along the plane of the winding layer.

17. The multilayer coupler of any one of claims 1 to 16 wherein the coil is configured as one continuous winding.

18. The multilayer coupler of any one of claims 1 to 17 wherein the coil is a wire harness comprising a plurality of wires bundled together.

19. The multilayer coupler of any one of claims 1 to 18, wherein the coil forms a first coil unit, and

the multi-layer coupler further comprises one or more additional coil units connected to the first coil unit, each additional coil unit comprising a second coil for wireless power transfer based on magnetic induction, the second coil having a multi-layer winding structure comprising a plurality of winding layers, each of the plurality of winding layers comprising a plurality of winding turns, wherein for each of the plurality of winding layers, where a corresponding coil transition of the second coil occurs between an intermediate winding turn of a winding layer of the plurality of winding layers and a winding turn of another winding layer, at least each intermediate winding turn of the plurality of intermediate winding turns of the plurality of winding turns of the winding layer comprises one or more transition portions.

20. The multilayer coupler of claim 19 wherein, for each of the additional coil units and each of the plurality of winding layers, a corresponding coil transition at a coil occurs at a location between a winding turn in a winding layer and a winding turn in another winding layer within the plurality of winding layers in the additional coil unit, each winding turn in the plurality of winding layers in the additional coil unit including one or more transition portions.

21. The multilayer coupler of any one of claims 1 to 20, wherein the multilayer coupler is a transmitting coupler configured to receive a time-varying current from a power source connected thereto for generating a magnetic field and for performing wireless power transfer between air gaps in cooperation with a receiving coupler based on magnetic induction technology.

22. The multilayer coupler of any one of claims 1 to 20 wherein the multilayer coupler is a receive coupler configured to couple with a magnetic field generated from a transmit coupler to induce a current in the receive coupler to power an electrical load; the electrical load is connected to the receive coupler to perform wireless power transfer between the air gaps based on magnetic induction technology in cooperation with the transmit coupler.

23. A wireless power transmitter, comprising:

a power supply configured to generate a time-varying current; the multilayer coupler of any one of claims 1 to 22 for use as a transmitting coupler and connected to the power source, wherein the transmitting coupler is configured to receive a time-varying current from the power source to generate a magnetic field and to perform wireless power transfer between air gaps based on magnetic induction technology in cooperation with a receiving coupler.

24. A wireless power receiver, comprising:

an electrical load; and

the multilayer coupler of any one of claims 1 to 22 for use as a receiving coupler and for connection to the electrical load, wherein the receiving coupler is configured to couple with a magnetic field generated from a transmitting coupler to induce a current in the receiving coupler for powering the electrical load, the electrical load being connected to the receiving coupler to perform wireless power transfer between air gaps in cooperation with the transmitting coupler based on magnetic induction technology.

25. A wireless power transfer system, comprising:

a wireless power transmitter, comprising:

a power supply configured to generate a time-varying current;

A wireless power receiver, comprising:

an electrical load; and

wherein at least one of the transmit coupler and the receive coupler is a multilayer coupler according to any one of claims 1 to 22, and the wireless power transmitter and the wireless power receiver are separated by an air gap.

26. The system of claim 25, wherein the receive coupler and the transmit coupler are each the multilayer coupler of any one of claims 1 to 22.

27. A method of manufacturing a multi-layer coupler for wireless power transfer, the method comprising:

28. The method of claim 27, wherein, for each of the plurality of winding layers, where a corresponding coil transition of the coil occurs between a winding turn of a winding layer of the plurality of winding layers and a winding turn of another winding layer, each of the plurality of winding turns of the winding layer includes one or more transition portions.

29. The method of claim 27, wherein for each of the plurality of winding layers and each of the plurality of intermediate winding turns in the winding layer, the intermediate winding turn of the winding layer and the winding turn of the winding turn of the other winding layer are the same in position where the corresponding coil transition of the coil occurs between the intermediate winding turn of the winding layer and the winding turn of the other winding layer.

30. The method of claim 27, wherein for each of the plurality of winding layers and one or more of the plurality of intermediate winding turns in the winding layer, the intermediate winding turn of the winding layer and the winding turn of the other winding layer differ in winding turn position where a corresponding coil transition of the coil occurs between the intermediate winding turn of the winding layer and the winding turn of the other winding layer.

31. The method of claim 27, wherein the plurality of winding turns of each of the plurality of winding layers collectively form a plurality of axial winding turn groups, each axial winding turn group comprising winding turns located at the same winding turn position.

32. The method of claim 31, wherein, in each of the plurality of axial winding turn groups, for each axial winding turn in the axial winding turn group other than the last axial winding turn, the winding turn comprises a first transition portion of the one or more transition portions at a location in the axial winding turn group where a corresponding coil transition of the coil occurs between the winding turn and the other winding turn.

33. The method of claim 32, wherein for each winding turn in the set of axial winding turns except for the last winding turn, at a first transition portion of the winding turn, a corresponding coil transition of the coil occurs between the winding turn in the set of axial winding turns to an immediately adjacent winding turn.

34. The method of claim 33, wherein

35. The method of claim 33, wherein

36. The method of claim 34 or claim 35, wherein,

37. The method of any one of claims 32 to 36, wherein in each of the plurality of axial winding turn groups, the first transition portion of each winding turn in the axial winding turn group is at least substantially aligned with the axial direction.

38. The method of claim 37, wherein in each of the plurality of winding layers, the first transition portion of each winding turn in the winding layer is at least substantially aligned with the transverse direction.

39. A method according to any one of claims 32 to 38, wherein, for each of the plurality of winding layers, each winding turn of the plurality of winding turns in the winding layer is wound along a plane of the winding layer and forms a complete loop at least substantially along the plane of the winding layer.

40. The method of any one of claims 32 to 38, wherein, for each of the plurality of winding layers, the one or more transition portions within each of the plurality of winding turns in the winding layer comprises a plurality of transition portions including a first transition portion at which a corresponding coil transition of the coil occurs between a winding turn of the winding layer of the plurality of winding layers and a winding turn of another winding layer.

41. The method of claim 40, wherein the plurality of transition portions of each of the plurality of winding turns are positioned along the winding turns based on a predetermined pattern.

42. The method of claim 40 or claim 41, wherein

43. The method of any one of claims 27 to 42, wherein the coil is configured as one continuous winding.

44. The method of any one of claims 27 to 43, wherein the coil is a wire harness comprising a plurality of wires bundled together.

45. The method of any one of claim 27 to claim 44, wherein,

the coil forms a first coil unit, and

46. The method of claim 45, wherein, for each of the additional coil units and each of the plurality of winding layers, a corresponding coil transition of the coil occurs at a location between a winding turn in a winding layer and a winding turn in another winding layer within the plurality of winding layers in the additional coil unit, each winding turn in the plurality of winding turns in the additional coil unit including one or more transition portions.

47. A wireless power transfer method, comprising:

At least one of the transmit coupler and the receive coupler is a multilayer coupler according to any one of claims 1 to 22, and the wireless power transmitter and the wireless power receiver are separated by an air gap.