WO2014181325A1

WO2014181325A1 - Improved inductor

Info

Publication number: WO2014181325A1
Application number: PCT/IL2014/050387
Authority: WO
Inventors: Dror Benatav
Original assignee: D.M. Benatav Ltd.
Priority date: 2013-05-05
Filing date: 2014-04-30
Publication date: 2014-11-13

Abstract

An inductor constituted of a first and a second ribbon shaped conductor, each of the first and second ribbon shaped conductors exhibiting a cross section of: a first insulated face; a second insulated face opposing the first insulated face; a first edge; and a second edge opposing the first edge, each of the first and second ribbon shaped conductors wound about the core such that the first edge thereof faces the core and the second edge thereof extends away from the core, the plurality of ribbon shaped conductors arranged so that the second insulated face of the first ribbon shaped conductor is adjacent the first face of the second ribbon shaped conductor, and the second insulated face of the second ribbon shaped conductor faces the first face of the first ribbon shaped conductor of the subsequent winding.

Description

IMPROVED INDUCTOR

TECHNICAL FIELD

[0001] The present invention relates generally to the field of inductors, and in particular to an inductor formed from a ribbon shaped wire.

BACKGROUND

[0002] An inductor is a coil of insulated wire, typically wound on a magnetic core, and in one embodiment is utilized as a choke wherein it acts to block high frequency signals while passing lower frequency signals, such as direct current. In high power circuits, such as solar converters, the inductor must handle high current loads without generating excess heat.

[0003] FIG. 1A illustrates a cut-away view of an inductor 10A comprising: a magnetic core 20 and a coiled circular shaped conductor 30 wound between opposing flanges 35. The term circular shaped refers to a cross section when viewed end on. As can be seen a large amount of unused space appeais between the various loops of coiled circular shaped conductor 30, leading to a poor fill factor. The term fill factor refers to the percentage of area available for the conductor actually occupied by a conductor. The area is defined by a representative cross section of the volume to be filled, i.e. a cut of the area between flanges 35. A high fill factor will thus provide more conductor per unit volume of space contributing to smaller packaging. Circular shaped conductor 30 may be a single wire, or a high frequency litz wire comprising a plurality of conductors. The fill factor of a litz wire is yet further reduced by the need to have a plurality of coated strands, each of diameter small enough to allow for easy winding.

[0004] Inductor 10A exhibits a length, L, defining the length along the bobbin, or core, upon which the circular shaped conductor 30 is wound, and is determined by the distance between flanges 35. For a tightly packed circular shaped conductor 30, the number of turns of wire, N, is defined by L for a particular wire diameter, D. Diameter D of the circular shaped conductor 30, for a single layer inductor, defines the second dimension of the cross sectional area, denoted H. The cross sectional area of such a wire, denoted A, is determined by the formula π*(Ό/2)². Neglecting the area required by the insulation, the area actually filled by circular shaped the fill factor of inductor 10A, expressed in percentage, is thus:

FILLFACTOR = ((N*A)/ (H * L))* 100 EQ. 1

Utilizing an 8mm diameter wire, an assuming N=14, L is 112 mm. The fill factor is thus determined according to EQ. 1 to be 78.5%. Unfortunately, such a wire is very thick and is thus not easily formed into an inductor. Furthermore, the skin effect of such a thick wire does not allow for use with high frequencies, since only the area near the outer surface is effectively utilized.

[0005] Use of litz wire resolves the high frequency and formability issues. A typical litz wire of 8mm diameter, appropriate for use with frequencies of 15 - 20 kHz, exhibits 22 bundles of 24 strands of coated wire each, each coated wire having a diameter of 0.25 mm. The total cross section A of such a wire is then the sum of the individual cross sections, i.e.

Litz Cross Section = 22 * 24* π *(0.25/2)² EQ. 2

Plugging in the Litz Cross section for A of EQ. 1, results in a fill factor of about 40%.

[0006] The low fill factor has led to the use a ribbon shaped conductor as illustrated in FIG. IB, which shows a cut-away view of an inductor 10B comprising: magnetic core 20 and a coiled ribbon shaped conductor 40. The term ribbon shaped refers to a cross section when viewed end on, as illustrated in FIG. 1C, with the cross section of ribbon shaped conductor 40 exhibiting a pair of parallel faces, in particular a first face 50 and second face 60, and a pair of parallel edges, in particular a first edge 70 and a second edge 80. The length of each face 50, 60 is at least 4 times the dimension of each of edges 70, 80. The length of face 50, 60 is often called the ribbon width and the dimension of edges 70, 80 is often called the ribbon thickness. The above has been described in an embodiment wherein faces 50 and 60 are identical, however this is not meant to be limiting in any way. Similarly, the above has been described in an embodiment wherein edges 70 and 80 are identical, however this is not meant to be limiting in any way. The thickness of edges 70, 80 of ribbon shaped conductor 40 is selected in view of the expected frequencies to be handled, particularly taking into account the frequency dependent skin effect. Thus, while a thicker wire would be desirable to reduce DC resistance, there is a limitation to the thickness which can be achieved. Edges of ribbon shaped conductor 40 are typically coated with an insulator so as to avoid short circuits from adjacent conductors. [0007] Inductor 10B exhibits a plurality of layers of coiled ribbon shaped conductor 40, which may represent a single coil of ribbon shaped wire 40, or more typically a plurality of coils of ribbon shaped wire 40 thus providing a high fill factor. Due the above described skin effect limiting the usable thickness of ribbon shaped wire 40, a plurality of coils of ribbon shaped wire 40 are provided for a reduced overall DC resistance. Unfortunately, the arrangement of inductor 10B leads to capacitive coupling between adjacent winding layers which leads to reduced effective inductance and induced electromagnetic interference (EMI). Furthermore, winding a bifilar or trifilar arrangement of ribbon shaped wire 40, where the bifilar arrangements are horizontally laid across core 20, leads to unsymmetrical crossings when changing layers. Furthermore remaining in one layer results in an extremely long inductor, which is not useful. Winding a bifilar arrangement of ribbon shaped wire 40 where the bifilar arrangements are one above the other, the differing layers exhibit different overall lengths of wire, thus resulting in circulating currents in high power applications. Additionally, utilizing multiple layers results in outer layers being further removed from the core, than inner layers, thus affecting magnetic performance.

SUMMARY OF THE INVENTION

[0008] In view of the discussion provided above and other considerations, the present disclosure provides methods and apparatus to overcome some or all of the disadvantages of prior and present inductor arrangements. In one exemplary embodiment an inductor is enabled comprising: a core; a first ribbon shaped conductor having a first length; and a second ribbon shaped conductor having a second length, each of the first and second ribbon shaped conductors exhibiting a cross section of: a first insulated face; a second insulated face opposing the first insulated face; a first edge; and a second edge opposing the first edge, the dimension of each of the first insulated face and the second insulated face at least 4 times larger than the dimension of each of the first edge and the second edge of the respective ribbon shaped conductor, each of the first and second ribbon shaped conductors wound about the core such that the first edge thereof faces the core and the second edge thereof extends away from the core, the plurality of ribbon shaped conductors arranged so that the second insulated face of the first ribbon shaped conductor is adjacent the first face of the second ribbon shaped conductor, and the second insulated face of the second ribbon shaped conductor faces the first face of the first ribbon shaped conductor of the subsequent winding.

[0009] In one further embodiment the first length is substantially equal to the second length. In another further embodiment a first end of the first ribbon shaped conductor is electrically connected to a first end of the second ribbon shaped conductor, and a second end of the first ribbon shaped conductor is electrically connected to a second end of the second ribbon shaped conductor.

[00010] In one further embodiment the first insulated face dimension and the second insulated face dimension are equal. In yet one further embodiment the first and second insulated face dimensions are at least 8 times the respective first edge. In yet another further embodiment the first edge dimension and the second edge dimension are equal.

[00011] In one further embodiment the inductor further comprises a third ribbon shaped conductor having a length substantially equal to the first length and the second length, the third ribbon shaped conductor exhibiting a cross section of: a first insulated face; a second insulated face opposing the first insulated face; a first edge; and a second edge opposing the first edge, the dimensions of each of the first insulated face of the third ribbon shaped conductor, the second insulated face of the third ribbon shaped conductor, the first edge of the third ribbon shaped conductor and the second edged of the third ribbon shaped conductor substantially equal to the respective dimension of each of the first ribbon shaped conductor and the second ribbon shaped conductor, the third ribbon shaped conductor wound about the core such that the first edge thereof faces the core and the second edge thereof extends away from the core, the third ribbon shaped conductor arranged so that the second insulated face of the second ribbon shaped conductor is adjacent the first face of the third ribbon shaped conductor and the second insulated face of the third ribbon shaped conductor faces the first face of the first ribbon shaped conductor of the subsequent winding. In one yet further embodiment the inductor further comprises a fourth ribbon shaped conductor having a length substantially equal to the length of the first ribbon shaped conductor, the second ribbon shaped conductor and the third ribbon shaped conductor, the fourth ribbon shaped conductor exhibiting a cross section of: a first insulated face; a second insulated face opposing the first insulated face; a first edge; and a second edge opposing the first edge, the dimensions of each of the first insulated face of the fourth ribbon shaped conductor, the second insulated face of the fourth ribbon shaped conductor, the first edge of the fourth ribbon shaped conductor and the second edged of the fourth ribbon shaped conductor substantially equal to the respective dimension of each of the first ribbon shaped conductor, the second ribbon shaped conductor and the third ribbon shaped conductor, the fourth ribbon shaped conductor wound about the core such that the first edge thereof faces the core and the second edge thereof extends away from the core, the fourth ribbon shaped conductor arranged so that the second insulated face of the third ribbon shaped conductor is adjacent the first face of the fourth ribbon shaped conductor, and the second insulated face of the fourth ribbon shaped conductor faces the first face of the first ribbon shaped conductor of the subsequent winding.

[00012] In one further embodiment the core is a magnetic core. In another further embodiment the core exhibits a rectangular cross section.

[00013] In one further embodiment the inductor is arranged to be a choke for a high power signal exhibiting a frequency greater than 10 kHz. In another further embodiment the inductor is arranged to be a choke for a power signal exhibiting an RMS value in excess of 20 Amperes and a frequency of greater than 10 kHz. In yet another further embodiment the fill factor of the inductor is greater than 80%.

[00014] Additional features and advantages of the invention will become apparent from the following drawings and description.

BRIEF DESCRIPTION OF DRAWINGS

[00015] For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, purely by way of example, to the accompanying drawings in which like numerals designate corresponding elements or sections throughout.

[00016] 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:

[00017] FIG. 1A illustrates a cut-away view of an inductor comprising a magnetic core and a coiled circular shaped conductor in accordance with the prior art;

[00018] FIG. IB illustrates a cut-away view of an inductor comprising a magnetic core and a plurality of layers of ribbon shaped conductor in accordance with the prior art;

[00019] FIG. 1C illustrates a cross section of the ribbon shaped conductor of

Fig. IB;

[00020] FIGs. 2A - 2D illustrate various views of an exemplary bifilar inductor comprising first and second ribbon shaped conductors;

[00021] FIGs. 3 A - 3B illustrate various views of an exemplary trifilar inductor comprising first, second and third ribbon shaped conductors;

[00022] FIGs. 4A - 4B illustrate various views of an exemplary quadfilar inductor comprising first, second, third and fourth ribbon shaped conductors; and

[00023] FIG. 5 illustrates a perspective view of an exemplary choke formed from the inductor of FIG. 3 A.

DESCRIPTION OF EMBODIMENTS

[00024] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is applicable to other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

[00025] FIGs. 2A - 2C illustrate various views of an exemplary bifilar inductor

100 comprising first ribbon shaped conductor 110 and second ribbon shaped conductor 120, and FIG. 2D illustrates further detail of the arrangement of the faces of first and second ribbon shaped conductors 110, 120, the various being described together for ease of understanding. Ribbon shaped conductors 110, 120 are formed as described above in relation to FIG. 1C. First and second ribbon shaped conductors 110, 120 are wound about a core 20, illustrated for simplicity as an air core for ease of illustration. [00026] First ribbon shaped conductor 110 exhibits a length, preferably identical to the length of second ribbon shaped conductor 120 and are coated with an insulating layer (not shown), such as a lacquer to prevent short circuits. First ribbon shaped conductor 110 and second ribbon shaped conductor are laid about core 20 with first edge 70 facing core 20 and second edge 80 facing away from core 20. In an exemplary embodiment first edge 50 is in contact with core 20. The first end of first ribbon shaped conductor 110 is preferably connected to the first end of second ribbon shaped conductor 120 and the second end of first ribbon shaped conductor 110 is preferably connected to the second end of second ribbon shaped conductor 120 so as to form a pair of parallel conducting paths. At the beginning of the winding, first face 50 of first ribbon shaped conductor 110 faces, and is adjacent to a first flange 35A. Second face 60 of first ribbon shaped conductor 110 faces, and is adjacent to, first face 50 of second ribbon shaped conductor 120. Second face 60 of second ribbon shaped conductor 120 generally faces the subsequent winding of first face 50 of first ribbon shaped conductor 110, it being understand that that at the last winding second face 60 of second ribbon shaped conductor 120 faces a second flange 35B.

[00027] In such a manner, the reduced thickness of first and second ribbon shaped conductors 110, 120 provide for improved high frequency performance, while the parallel laying of a plurality of ribbon shaped conductors enables an improved effective DC resistance. By laying each of first and second ribbon shaped conductors 110, 120 with first edge 70 facing core 20, each of first and second ribbon shaped conductors exhibit an identical length and arrangement in regards to core 20, thus preventing any circulating currents. First and second ribbon shaped conductors 110, 120 are preferably laid simultaneously about core 20, thus acting as a single conductor with improved high frequency properties due to the reduced thickness of the individual ribbon shaped conductors 110, 120.

[00028] The aspect ratio of first and second ribbon shaped conductors 110, 120, i.e. the ratio of the dimension of faces 50, 60 to edges 70, 80 are preferably at least 4: 1, preferably at least 8: 1. In one particular embodiment, each of first and second ribbon shaped conductors 110, 120 exhibit faces 50, 60 with a dimension of 10 mm and edges 70, 80 with a dimension of 1.25 mm. The fill factor of such a ribbon shaped conductor is in excess of 80% as measured experimentally, limited only by curvature of the edges of first and second ribbon shaped conductors 110, 120, the thickness of the lacquer insulation, and the amount of force applied by flanges 35. Such an arrangement provides improved space utilization and reduced core losses. Experimental measurements show an improved DC resistance as compared to the litz wire embodiment described above, i.e. 3.9 miUiohms as opposed to 6.1 miUiohms for the litz wire embodiment, with equivalent total losses at a frequency of 17 kHz with an RMS current value of 90 mA to the litz wire embodiment. The inductance of the exemplary inductor 200 was measured to be substantially equivalent to the inductance of the equivalent litz wire embodiment, i.e. 0.2 millihenry (mH), thus indicating that some increased reactance was present. However, the small increased reactance results in a significantly reduced form factor.

[00029] Preferably, first face 50 and second face 60 of each of first and second ribbon shaped conductors 110, 120 are of identical dimensions so as to prevent circulating currents, however in certain embodiments the dimension of first face 50 and second face 60 of either of first ribbon shaped conductor 110 and second ribbon shaped conductor 120 need not be the same without exceeding the scope. Preferably, first edge 70 and second edge 80 of each of first and second ribbon shaped conductors 110, 120 are of identical dimensions so as to prevent circulating currents, however in certain embodiments the dimension of first edge 70 and second edge 80 of either of first ribbon shaped conductor 110 and second ribbon shaped conductor 120 need not be the same without exceeding the scope. Preferably all dimensions of first ribbon shaped conductor 110 are substantially identical to the respective dimensions of second ribbon shaped conductor 120, however this is not meant to be limiting in any way, and in certain embodiments at least one dimension differs without exceeding the scope.

[00030] FIG. 3A illustrates a perspective view of an exemplary trifilar inductor

200 comprising first ribbon shaped conductor 110, second ribbon shaped conductor 120 and third ribbon shaped conductor 130, substantially as described above in relation to bifilar inductor 100, with the addition of third ribbon shaped inductor 130. FIG. 3B illustrates the arrangement of first, second and third ribbons shaped conductors 110, 120, 130 in respect to flanges 35A, 35B. Preferably the dimensions of third ribbon shaped conductor 130 are identical with respective dimensions of first and second ribbon shaped conductors 110, 120.

[00031] First ribbon shaped conductor 110 exhibits a length, preferably identical to the length of second ribbon shaped conductor 120 and third ribbon shaped conductor 130, and each are coated with an insulating layer (not shown), such as a lacquer to prevent short circuits. First ribbon shaped conductor 110, second ribbon shaped conductor 120 and third ribbon shaped conductor 130 are laid about core 20 with first edge 70 facing core 20 and second edge 80 facing away from core 20. In an exemplary embodiment first edge 50 is in contact with core 20. The first end of first ribbon shaped conductor 110 is preferably connected to the first end of each of second ribbon shaped conductor 120 and third ribbon shaped conductor 130 and the second end of first ribbon shaped conductor 110 is preferably connected to the first end of each of second ribbon shaped conductor 120 and third ribbon shaped conductor 130 so as to form a triplet of parallel conducting paths. At the beginning of the winding, first face 50 of first ribbon shaped conductor 110 faces, and is adjacent to a first flange 35A. Second face 60 of first ribbon shaped conductor 110 faces, and is adjacent to, first face 50 of second ribbon shaped conductor 120. Second face 60 of second ribbon shaped conductor 130 faces, and is adjacent to, first face 50 of third ribbon shaped conductor 130. Second face 60 of third ribbon shaped conductor 130 generally faces the subsequent winding of first face 50 of first ribbon shaped conductor 110, it being understand that that at the last winding second face 60 of third ribbon shaped conductor 130 faces a second flange 35B.

[00032] In such a manner, the reduced thickness of first, second and third ribbon shaped conductors 110, 120, 130 provide for improved high frequency performance, while the parallel laying of a plurality of ribbon shaped conductors enables an improved effective DC resistance. By laying each of first, second and third ribbon shaped conductors 110, 120, 130 with first edge 70 facing core 20, each of first and second ribbon shaped conductors exhibit an identical length and arrangement in regards to core 20, thus preventing any circulating currents. First, second and third ribbon shaped conductors 110, 120, 130 are preferably laid simultaneously about core 20, thus acting as a single conductor with improved high frequency properties due to the reduced thickness of the individual ribbon shaped conductors 110, 120, 130.

[00033] FIGs. 4A - 4D illustrate various views of an exemplary quadfilar inductor 300 comprising first ribbon shaped conductor 110, second ribbon shaped conductor 120, third ribbon shaped conductor 130 and fourth ribbon shaped conductor 140, substantially as described above in relation to bifilar inductor 100 and trifilar inductor 200. Preferably the dimensions of fourth ribbon shaped conductor 140 are identical with respective dimensions of each of first, second and third ribbon shaped conductors 110, 120, 130.

[00034] First ribbon shaped conductor 110 exhibits a length, preferably identical to the length of second ribbon shaped conductor 120, third ribbon shaped conductor 130 and fourth ribbon shaped conductor 140, and each are coated with an insulating layer (not shown), such as a lacquer to prevent short circuits. First ribbon shaped conductor 110, second ribbon shaped conductor 120, third ribbon shaped conductor 130 and fourth ribbon shaped conductor 140 are laid about core 20 with first edge 70 facing core 20 and second edge 80 facing away from core 20. In an exemplary embodiment first edge 50 is in contact with core 20. The first end of first ribbon shaped conductor 110 is preferably connected to the first end of each of second ribbon shaped conductor 120, third ribbon shaped conductor 130 and fourth ribbon shaped conductor 140 so as to form a quadruplet of parallel conducting paths. At the beginning of the winding, first face 50 of first ribbon shaped conductor 110 faces, and is adjacent to a first flange 35A. Second face 60 of first ribbon shaped conductor 110 faces, and is adjacent to, first face 50 of second ribbon shaped conductor 120. Second face 60 of second ribbon shaped conductor 130 faces, and is adjacent to, first face 50 of third ribbon shaped conductor 130. Second face 60 of third ribbon shaped conductor 130 generally faces first face 50 of fourth ribbon shaped conductor 140. Second face 60 of fourth ribbon shaped conductor 140 generally faces the subsequent winding of first face 50 of first ribbon shaped conductor 110, it being understand that that at the last winding second face 60 of fourth ribbon shaped conductor 140 faces a second flange 35B.

[00035] In such a manner, the reduced thickness of first, second, third and fourth ribbon shaped conductors 110, 120, 130, 140 provide for improved high frequency performance, while the parallel laying of a plurality of ribbon shaped conductors enables an improved effective DC resistance. By laying each of first, second, third and fourth ribbon shaped conductors 110, 120, 130, 140 with first edge 70 facing core 20, each of first and second ribbon shaped conductors exhibit an identical length and arrangement in regards to core 20, thus preventing any circulating currents. First, second, third and fourth ribbon shaped conductors 110, 120, 130, 140 are preferably laid simultaneously about core 20, thus acting as a single conductor with improved high frequency properties due to the reduced thickness of the individual ribbon shaped conductors 110, 120, 130, 140. [00036] FIG. 5 illustrates a perspective view of an exemplary choke 400 formed from the inductors of FIG. 3 A. Choke 400 exhibits a D shaped core 410 with a pair of serially connected trifilar inductors 200, as described above, laid about the various parallel arms of D shaped core 410.

[00037] The inductors described herein are particularly advantageous for use with high power application of 20 Amperes RMS and above. The inductors described herein may be used as chokes, transformers or auto-transformers without exceeding the scope.

[00038] It is appreciated that certain features of the invention, 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 invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

[00039] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as are commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods are described herein.

[00040] All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the patent specification, including definitions, will prevail. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

[00041] It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather the scope of the present invention is defined by the appended claims and includes both combinations and sub-combinations of the various features described hereinabove as well as variations and modifications thereof, which would occur to persons skilled in the art upon reading the foregoing description.

Claims

CLAIMS What is claimed is:

1. An inductor comprising:

a core;

a first ribbon shaped conductor having a first length; and

a second ribbon shaped conductor having a second length,

each of said first and second ribbon shaped conductors exhibiting a cross section of:

a first insulated face;

a second insulated face opposing said first insulated face; a first edge; and

a second edge opposing said first edge,

the dimensions of each of said first insulated face and said second insulated face at least 4 times larger than the dimension of each of said first edge and said second edge of the respective ribbon shaped conductor,

each of said first and second ribbon shaped conductors wound about said core such that the first edge thereof faces said core and the second edge thereof extends away from said core,

said plurality of ribbon shaped conductors arranged so that said second insulated face of said first ribbon shaped conductor is adjacent said first face of said second ribbon shaped conductor, and said second insulated face of said second ribbon shaped conductor faces said first face of said first ribbon shaped conductor of the subsequent winding.

2. The inductor according to claim 1, wherein the first length is substantially equal to the second length.

3. The inductor according to claim 1, wherein a first end of said first ribbon shaped conductor is electrically connected to a first end of said second ribbon shaped conductor, and a second end of said first ribbon shaped conductor is electrically connected to a second end of said second ribbon shaped conductor.

4. The inductor according to either any of claims 1 - 3, wherein said first insulated face dimension and said second insulated face dimension are equal.

5. The inductor according to claim 4, wherein said first and second insulated face dimension are at least 8 times the respective first edge.

6. The inductor according to claim 4, wherein said first edge dimension and said second edge dimension are equal.

7. The inductor according to claim 1, further comprising a third ribbon shaped conductor having a length substantially equal to the first length and the second length, said third ribbon shaped conductor exhibiting a cross section of:

a first insulated face;

a second insulated face opposing said first insulated face; a first edge; and

a second edge opposing said first edge,

the dimensions of each of said first insulated face of said third ribbon shaped conductor, said second insulated face of said third ribbon shaped conductor, said first edge of said third ribbon shaped conductor and said second edged of said third ribbon shaped conductor substantially equal to the respective dimension of each of said first ribbon shaped conductor and said second ribbon shaped conductor,

said third ribbon shaped conductor wound about said core such that the first edge thereof faces said core and the second edge thereof extends away from said core, said third ribbon shaped conductor arranged so that said second insulated face of said second ribbon shaped conductor is adjacent said first face of said third ribbon shaped conductor and said second insulated face of said third ribbon shaped conductor faces said first face of said first ribbon shaped conductor of the subsequent winding.

8. The inductor according to claim 7, further comprising a fourth ribbon shaped conductor having a length substantially equal to the length of said first ribbon shaped conductor, said second ribbon shaped conductor and said third ribbon shaped conductor,

said fourth ribbon shaped conductor exhibiting a cross section of:

a first insulated face; a second insulated face opposing said first insulated face;

a first edge; and

a second edge opposing said first edge,

the dimensions of each of said first insulated face of said fourth ribbon shaped conductor, said second insulated face of said fourth ribbon shaped conductor, said first edge of said fourth ribbon shaped conductor and said second edged of said fourth ribbon shaped conductor substantially equal to the respective dimension of each of said first ribbon shaped conductor, said second ribbon shaped conductor and said third ribbon shaped conductor,

said fourth ribbon shaped conductor wound about said core such that the first edge thereof faces said core and the second edge thereof extends away from said core, said fourth ribbon shaped conductor arranged so that said second insulated face of said third ribbon shaped conductor is adjacent said first face of said fourth ribbon shaped conductor, and said second insulated face of said fourth ribbon shaped conductor faces said first face of said first ribbon shaped conductor of the subsequent winding.

9. The inductor according to claim 1 wherein said core is a magnetic core.

10. The inductor according to claim 1, wherein said core exhibits a rectangular cross section.

11. The inductor according to claim 1, wherein said inductor is arranged to be a choke for a high power signal exhibiting a frequency greater than 10 kHz.

12. The inductor according to claim 1, wherein said inductor is arranged to be a choke for a power signal exhibiting an RMS value in excess of 20 Amperes and a frequency of greater than 10 kHz.

13. The inductor according to claim 1, wherein the fill factor of said inductor is greater than 80%.