WO2015170242A1

WO2015170242A1 - Wireless power outlet and inductive coil thereof

Info

Publication number: WO2015170242A1
Application number: PCT/IB2015/053249
Authority: WO
Inventors: Elieser Mach; Ilya GLUZMAN; Arik Rofe; Amir SALHUV
Original assignee: Powermat Technologies Ltd.
Priority date: 2014-05-04
Filing date: 2015-05-04
Publication date: 2015-11-12

Abstract

A wireless power outlet configured to inductively transmit electrical power wirelessly to a suitable secondary unit is provided. The wireless power outlet comprises a primary inductive coil, a resonant circuit connected to the primary inductive coil and comprising a driver configured to provide an oscillating driving voltage thereto, and a controller configured to direct operation of the wireless power outlet. The primary inductive coil comprises at least two windings arranged substantially parallely to one another, and being arranged so as to be incompletely superimposed with one another.

Description

WIRELESS POWER OUTLET AND INDUCTIVE COIL

THEREOF

FIELD OF THE INVENTION

The present disclosure relates to wireless power outlets, and to inductive coils thereof.

BACKGROUND OF THE INVENTION

The use of a wireless non-contact system for the purposes of automatic identification or tracking of items is an increasingly important and popular functionality.

Inductive power coupling allows energy to be transferred from a power supply to an electric load without a wired connection therebetween. An oscillating electric potential is applied across a primary inductor. This sets up an oscillating magnetic field in the vicinity of the primary inductor. The oscillating magnetic field may induce a secondary oscillating electrical potential in a secondary inductor placed close to the primary inductor. In this way, electrical energy may be transmitted from the primary inductor to the secondary inductor by electromagnetic induction without a conductive connection between the inductors.

When electrical energy is transferred from a primary inductor to a secondary inductor, the inductors are said to be inductively coupled. An electric load wired in series with such a secondary inductor may draw energy from the power source wired to the primary inductor when the secondary inductor is inductively coupled thereto.

SUMMARY OF THE INVENTION

According to one aspect of the presently disclosed subject matter, there is provided a wireless power outlet configured to inductively transmit electrical power wirelessly to a suitable secondary unit, the wireless power outlet comprising:

• a primary inductive coil; • a resonant circuit connected to the primary inductive coil and comprising a driver configured to provide an oscillating driving voltage thereto; and

• a controller configured to direct operation of the wireless power outlet; wherein the primary inductive coil comprises at least two windings arranged substantially parallely to one another, the windings being arranged so as to be incompletely superimposed with one another.

The windings may be arranged such that a central perpendicular axis of each one is substantially coincident with that of the other.

Each of the two windings may have a shape different from the other of the windings. (It will be appreciated that herein the specification and claims, the description of an element "having a shape" or similar language is to be understood as the element being formed into that shape.)

A first of the windings may have a circular shape, with a second of the windings having a non-circular shape. The non-circular shape may be a polygon. The polygon may be a square. The polygon may be selected from the group consisting of triangles, rhombuses, rectangles, trapezoids, pentagons, hexagons, and stars. At least one of the shapes may be selected from the group consisting of ovals, ellipses, and crescents.

Two or more of the windings may have the same shape and be rotated with respect to one another about a Z-axis perpendicular to the windings.

Each winding may comprise a coiled wire.

Each of the windings may comprise a metal core. The core may be made of a ferromagnetic material. The windings may share a common core.

The wireless power outlet may further comprise a charging surface disposed above and substantially parallel to the windings.

The wireless power outlet may be designed to operate in a range between about 100kHz and about 500kHz.

The wireless power outlet may be further configured to communicate with the secondary unit.

According to another aspect of the presently disclosed subject matter, there is provided a primary inductive coil for use with a wireless power outlet and configured to facilitate inductive transmission of electrical power to a suitable secondary unit, the primary inductive coil comprising at least two windings arranged substantially parallely to one another, the windings being arranged so as to be incompletely superimposed with one another.

Each of the two windings may have a shape different from the other of the windings.

Each winding may comprise a coiled wire.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the embodiments and to show how it may be carried into effect, reference will now be made, purely by way of example, to the accompanying drawings.

With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention; the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. In the accompanying drawings: Fig. 1 is a schematic illustration of a wireless power outlet according to the presently disclosed subject matter;

Fig. 2 is a schematic side view of a primary inductive coil of the wireless power outlet illustrated in Fig. 1 ; and

Figs. 3A and 3B are top views of windings of the primary inductive coil illustrated in Fig. 2.

DETAILED DESCRIPTION

As illustrated in Fig. 1 , there is provided a wireless power outlet 100, such as an inductive power outlet, a resonant power outlet, or the like, constituting an inductive transmitter configured to conductively transmit electrical power wirelessly to a suitable secondary unit (such as a wireless power receiver, e.g., an inductive receiver; not illustrated) remote therefrom. The wireless power outlet 100 comprises a primary inductive coil 1 10 connected to a resonant circuit 1 12 constituting a power source and comprising, inter alia, a driver 1 14. The driver 1 14 is configured to provide an oscillating driving voltage to the primary inductive coil 1 10. The wireless power outlet 100 may further comprise a controller 1 16, such as a microcontroller unit, to direct operation thereof. The wireless power outlet 100 may be designed to operate in any suitable range, for example about 100kHz to about 500kHz.

The wireless power outlet 100 as described herein may be configured to communicate with the secondary unit, for example via the primary inductive coil 110. Such a receiver may, inter alia, be configured to transmit signals to the wireless power outlet 100, which the wireless power outlet is configured to decode and take suitable actions based thereon.

According to one example, as illustrated in Figs. 2, the primary inductive coil 110 comprises two windings 118, each disposed substantially along an XY plane (herein the specification and claims, a Cartesian coordinate system will be used as the convention to describe the primary inductive coil and its windings, as well as its environment; the use of this convention is for clarity of the disclosure only, and is not to be construed as limiting) and arranged one atop another as layers, substantially parallel to one another. The windings 1 18 may be co-disposed such that central axes thereof are substantially coincident along a Z-axis perpendicular thereto. The windings 1 18 define a plane thereabove where the secondary unit may be placed, e.g., for inductive power transfer thereto. Accordingly, the wireless power outlet 100 may comprise a charging surface 120 substantially parallel to and disposed above the windings 1 18, providing a suitable area for placement of the secondary unit during charging.

As illustrated in Fig. 3 A, each of the windings 1 18 may comprise a single low- resistance wire 122, which is coiled. The wire 122 may comprise a plurality of thin wire strands, individually insulated and twisted and/or woven together. The strands may be organized in several levels, e.g., groups of twisted wires twisted together. Each of the windings 1 18 may be provided with a metal core 124, which may be made of a ferromagnetic material, such as iron, for guiding magnetic flux therethrough. The core 124 may be common to both of the windings 1 18.

According to some modifications, the wire 122 may be a litz wire, e.g., having a low AC-resistance (i.e., impedance). The litz wire may be provided according to any suitable design, many of which are known in the art and available in a wide variety of configurations.

The windings 1 18 may be formed and/or arranged such that they are substantially incompletely superimposed with one another, i.e., designed such that one is set over the other and overlays it without completely overlapping, e.g., as per examples described below.

As illustrated further in Fig. 3A and as illustrated in Fig. 3B, each of the windings 1 18 may be formed into any suitable shape, for example a circle (as in Fig. 3A) or a square (Fig. 3B). It will be appreciated that these represent only examples of shapes into which each of the windings 1 18 may be formed; they may also be formed into other shapes, including, but not limited to, triangles, rhombuses, rectangles, trapezoids, pentagons, hexagons, other polygons, stars of any suitable number of vertices, ovals, ellipses, crescents, etc., without departing from the scope of the presently disclosed subject matter. A winding having the shape of a polygon may be regular or irregular, convex or concave, etc. In addition, some of the sides of the polygon may be curved.

It will be appreciated that herein the specification and claims, a description of the shape of a winding 1 18 refers to its approximate shape. Owing to, inter alia, manufacturing and physical limitations, a typical winding 1 18 provided according to the presently disclosed subject matter may only approximate the actual shape (e.g., a square winding may in fact have slightly rounded corners, sides of slightly differing sides or not exactly parallel to one another, etc.). Similarly, a description of dispositions and/or orientations of windings are approximate, and take into account, inter alia, manufacturing and physical limitations.

According to some examples, the primary inductive coil 1 10 comprises more than two windings 1 18, which may be formed in different shapes, and which may all share a common core 124. The windings 1 18 may be provided all have different shapes, or provided such that some are of the same shape, and some are of different shapes.

According to further examples, the primary inductive coil comprises two or more windings 1 18 of the same shape, but rotated with respect to one another about a Z-axis (e.g., the primary inductive coil may comprise two square windings with one rotated with respect to the other by 45° about the Z-axis, such that together the form an eight-sided star). Such windings 118 may be the sole windings in a primary inductive coil 110 (for example in order to provide a shape difficult to form with a single winding), or they may be provided along with windings having other shapes.

The degree to which magnetic flux from the primary inductive coil reaches a secondary inductive coil of the secondary unit, which is associated with higher transfer of electrical power, is expressed by a coupling coefficient (sometimes referred to as a "coupling factor"). The coupling factor ranges from 0 to 1, with a higher value indicating tighter coupling (i.e., more magnetic flux reaching the secondary inductive coil). Parameters which influence the coupling factor may include, but are not limited to, the geometry of the windings 1 18 and the misplacement (i.e., misalignment) of the secondary inductive coil with respect to the primary inductive coil 1 10.

It has been found that providing the windings 1 18 as circular (i.e., having a substantially circular shape in the XY plane) tends to concentrate the magnetic flux in the center of the area thereabove. Thus, for a given geometry of a secondary inductive coil, placement thereof on the charging surface 120 such that its center is aligned with the center of the windings 1 18 is associated with a relatively high coupling factor, with the coupling factor decreasing relatively rapidly as the misalignment is increased.

It has been further found that providing the windings 1 18 as square (i.e., having a substantially square shape in the XY plane) tends to more evenly distribute (compared to a circular winding 118) the magnetic flux over the area thereabove. Thus, for a given geometry of a secondary inductive coil, placement thereof on the charging surface 120 such that its center is aligned with the center of the windings 118 is associated with a coupling factor which is somewhat lower than that associated with equivalent circular windings, with the coupling factor decreasing slower as the misalignment is increased.

Similarly, other shapes of windings 118 provide advantages/disadvantages, e.g., vis-a-vis the distribution of the coupling factor thereabove, compared with those provided by other shapes.

Accordingly, a primary inductive coil 1 10 comprising windings 118 having different shapes may function to mitigate some of the disadvantages of each shape. For example, a primary inductive coil 110 having one winding 118 with a substantially circular shape and one winding with a substantially square shape combines the tendencies of each shape of winding as described above, i.e., the effect of the circular winding 118 is to increase magnetic flux in the center area above the primary inductive coil 110, and the effect of the square winding is to increase magnetic flux along outer edges of the area above the primary inductive coil, thereby more equally distributing magnetic flux than would be achieved if windings of a single shape were used. Thus, for a given geometry of a secondary inductive coil, placement thereof on the charging surface 120 such that its center is aligned with the center of the windings 1 18 is associated with a coupling factor which is higher than would be achieved with only square windings, and placement thereof on the charging surface with a misalignment is associated with a coupling factor which is higher than would be achieved with only circular windings.

According to some examples, the primary inductive coil 110 may comprise two or more windings 118 having different parameters from one another. For example, each may be shielded in different area, e.g., to allow some of the magnetic flux penetrate for sensing purposes, etc. Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations and modifications can be made without departing from the scope of the invention mutatis mutandis.

Technical and scientific terms used herein should have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure pertains. Nevertheless, it is expected that during the life of a patent maturing from this application many relevant systems and methods will be developed. Accordingly, the scope of the terms such as computing unit, network, display, memory, server and the like are intended to include all such new technologies a priori.

The terms "comprises", "comprising", "includes", "including", "having" and their conjugates mean "including but not limited to" and indicate that the components listed are included, but not generally to the exclusion of other components. Such terms encompass the terms "consisting of and "consisting essentially of.

The phrase "consisting essentially of means that the composition or method may include additional ingredients and/or steps, but only if the additional ingredients and/or steps do not materially alter the basic and novel characteristics of the composition or method.

As used herein, the singular form "a", "an" and "the" may include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof.

The word "optionally" is used herein to mean "is provided in some embodiments and not provided in other embodiments". Any particular embodiment of the disclosure may include a plurality of "optional" features unless such features conflict.

Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases "ranging/ranges between" a first indicate number and a second indicate number and "ranging/ranges from" a first indicate number "to" a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween. It should be understood, therefore, that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6 as well as non- integral intermediate values. This applies regardless of the breadth of the range.

It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the disclosure. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

Although the disclosure has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the disclosure.

All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present disclosure. To the extent that section headings are used, they should not be construed as necessarily limiting.

Claims

CLAIMS:

1. A wireless power outlet configured to inductively transmit electrical power wirelessly to a suitable secondary unit, the wireless power outlet comprising:

• a primary inductive coil;

• a resonant circuit connected to said primary inductive coil and comprising a driver configured to provide an oscillating driving voltage thereto; and

• a controller configured to direct operation of the wireless power outlet;

wherein said primary inductive coil comprises at least two windings arranged substantially parallely to one another, said windings being arranged so as to be incompletely superimposed with one another.

2. The wireless power outlet according to claim 1, wherein said windings are arranged such that a central perpendicular axis of each one is substantially coincident with that of the other.

3. The wireless power outlet according to any one of claims 1 and 2, wherein each of said two windings has a shape different from the other of said windings.

4. The wireless power outlet according to claim 3, wherein a first of said windings has a circular shape, and a second of said windings has a non-circular shape.

5. The wireless power outlet according to claim 4, wherein said non-circular shape is a polygon.

6. The wireless power outlet according to claim 5, wherein said polygon is a square.

7. The wireless power outlet according to claim 5, wherein said polygon is selected from the group consisting of triangles, rhombuses, rectangles, trapezoids, pentagons, hexagons, and stars.

8. The wireless power outlet according to any one of the claims 3 through 7, wherein at least one of said shapes is selected from the group consisting of ovals, ellipses, and crescents.

9. The wireless power outlet according to any one of the preceding claims, wherein two or more of said windings have the same shape and are rotated with respect to one another about a Z-axis perpendicular to said windings.

10. The wireless power outlet according to any one of the preceding claims, wherein each winding comprises a coiled wire.

11. The wireless power outlet according to claim 10, wherein each of said windings comprises a metal core.

12. The wireless power outlet according to claim 11, wherein said core is made of a ferromagnetic material.

13. The wireless power outlet according to any one of claims 11 and 12, wherein said windings share a common core.

14. The wireless power outlet according to any one of the preceding claims, further comprising a charging surface disposed above and substantially parallel to said windings.

15. The wireless power outlet according to any one of the preceding claims, designed to operate in a range between about 100kHz and about 500kHz.

16. The wireless power outlet according to any one of the preceding claims, being further configured to communicate with said secondary unit.

17. A primary inductive coil for use with a wireless power outlet and configured to facilitate inductive transmission of electrical power to a suitable secondary unit, the primary inductive coil comprising at least two windings arranged substantially parallely to one another, said windings being arranged so as to be incompletely superimposed with one another.

18. The primary inductive coil according to claim 17, wherein said windings are arranged such that a central perpendicular axis of each one is substantially coincident with that of the other.

19. The primary inductive coil according to any one of claims 17 and 18, wherein each of said two windings has a shape different from the other of said windings.

20. The primary inductive coil according to claim 19, wherein a first of said windings has a circular shape, and a second of said windings has a non-circular shape.

21. The primary inductive coil according to claim 20, wherein said non-circular shape is a polygon.

22. The primary inductive coil according to claim 21, wherein said polygon is a square.

23. The primary inductive coil according to claim 21, wherein said polygon is selected from the group consisting of triangles, rhombuses, rectangles, trapezoids, pentagons, hexagons, and stars.

24. The primary inductive coil according to any one of the claims 19 through 23, wherein at least one of said shapes is selected from the group consisting of ovals, ellipses, and crescents.

25. The primary inductive coil according to any one of claims 16 through 24, wherein two or more of said windings have the same shape and are rotated with respect to one another about a Z-axis perpendicular to said windings.

26. The primary inductive coil according to any one of claims 16 through 25, wherein each winding comprises a coiled wire.

27. The primary inductive coil according to claim 26, wherein each of said windings comprises a metal core.

28. The primary inductive coil according to claim 27, wherein said core is made of a ferromagnetic material.

29. The primary inductive coil according to any one of claims 27 and 28, wherein said windings share a common core.