EP1042768B1 - Planar transformer winding - Google Patents

Description

The present invention relates to a transformer winding planar with at least one primary winding and at least one secondary winding, and more particularly such a winding of the type whose primary and secondary windings include turns produced in the form of conductive tracks formed on the faces of a flat insulating support or several planar insulating supports stacked and interconnected, as necessary, by conductive holes passing through flat insulating supports.

In planar technology, a transformer winding, whether primary or secondary, consists of at least two portions of tracks conductive carried out on different faces of one or more supports insulating planes stacked so as to be able to present terminals of connection arranged on the periphery of the transformer, this in order to facilitate the electrical connection of the transformer. The portions of tracks conductors of the same winding follow spirals of the same direction and are electrically connected to each other to ensure continuity of the winding, by the inner ends of their spirals and, as of need, by some of the outer ends of their spirals at by means of conductive holes passing through the insulating support or supports.

According to current practice, the conductive tracks of the windings primary and secondary of a transformer are nested on the supports insulating planes so that we find when moving from the outside towards the center of a transformer, on any of the insulating supports plans, alternating primary and secondary turns.

Although generally satisfactory, this solution presents some disadvantages.

First, when you want to have numbers of turns different in the primary and secondary of a planar transformer, which is relatively frequent, it is necessary to carry out first, on one or several stacked flat insulating supports, primary windings and secondary with the same number of turns corresponding to the smallest of number of turns required. Then finish the winding with the largest number of turns by complementary turns drawn on one or more other flat insulating supports. This can lead to the use of a number high level of insulating supports stacked when it is important to reduce the most possible the number of flat insulating supports stacked for ease of production.

Furthermore, as the turns of the primary windings and secondary are alternated on the surface of the flat insulating supports, it is necessary to provide a spacing between them to ensure the desired electrical isolation between the primary and secondary of the transformer. As the electrical insulation constraints between primary and secondary of a transformer are often important, this results generally, a significant gap between each of the turns primary and secondary alternately drawn on the surface of the same flat insulating support. This interspire spacing reduces the density of the turns, so the number of turns that can be accommodated on a given surface of insulating plane support. Besides the fact that it limits the possibilities of reducing the size of the transformer, it reduces the magnetic coupling which leads to an increase in magnetic leaks. This results in a transformer less efficient than one might hope, especially regarding performance.

The present invention aims to overcome these drawbacks.

To this end, the invention relates to a transformer winding planar with at least one primary winding and at least one secondary winding with turns made in the form of tracks conductive formed on the faces of an insulating support and connected between them by means of conductive holes drilled in the insulating support, characterized by the fact that the portions of the primary windings and secondary carried by the same face of the insulating support are grouped by winding, in two distinct nested areas, of shapes one of the zones grouping side by side coils or portions of turns of the primary winding and the other zone grouping side by side turns or portions of turns of the secondary winding.

Such a structure, although geometrically complex, is no more technologically difficult to perform than that of the prior art.

On the other hand, it makes it possible to carry out on the two faces of the same planar insulating support, a whole winding, comprising windings primary and secondary with different number of turns. A transformer produced according to the invention can therefore comprise less than layers of supports, even if it generally comprises several, and by therefore be less expensive and less bulky.

It also makes it possible to bring together the turns within the same area on a plane insulating support face because these belong to a same primary or secondary winding for which the requirements of interspire isolation are always much less than the requirements insulation between primary and secondary windings. This allows improve the compactness of the transformer and therefore limit its losses magnetic.

In a particular embodiment of the invention, each portion winding forms a turn which extends over approximately 360 °.

This arrangement has the advantage of being simple, since it leads easily to full turns when two winding portions are electrically connected to each other by a conductive hole joining the inner ends of their turns.

Also in a particular embodiment, at least one of the windings is formed on each side of the support of a plurality of winding portions joined successively from one face to the other of the support in series by conductive holes.

We will see below that this arrangement, also complex geometrically, allows to have many turns of the primary winding (respectively secondary) opposite the secondary winding (respectively primary).

Advantageously, the turns of each winding have shapes such that they provide for overlapping recesses in which pass the conductive holes of the other winding.

It is possible with such an arrangement to best superimpose the primary and secondary windings, and thus improve performance transformer magnets.

The present invention also relates to a multiple winding for planar transformer, comprising a plurality of windings such as described above arranged one above the other on a plurality of assembled supports, primary and secondary windings respectively of said coils being electrically connected to each other other.

Said windings can then be connected either in series or in parallel.

It is also possible to provide several primaries and / or several secondary.

• la figure 1 est une vue en perspective d'un bobinage de transformateur selon l'invention;
• les figures 2 et 3 illustrent, respectivement en perspective et en vue de dessus, une portion d'enroulement selon l'invention;
• la figure 4 illustre un autre mode de réalisation d'un bobinage selon l'invention, un seul enroulement étant représenté; et
• la figure 5 est une vue en perspective d'un autre mode de réalisation de l'invention.

A particular embodiment of the invention will now be described, by way of nonlimiting example, with reference to the appended schematic drawings in which:

• Figure 1 is a perspective view of a transformer winding according to the invention;
• Figures 2 and 3 illustrate, respectively in perspective and in top view, a winding portion according to the invention;
• FIG. 4 illustrates another embodiment of a winding according to the invention, a single winding being shown; and
• Figure 5 is a perspective view of another embodiment of the invention.

It will first be noted that the drawings are not shown the insulating supports on which the conductive tracks are attached the arrangement of which is the subject of the present invention. These supports are in effect perfectly known in themselves, as well as how to superimpose, and form conductive tracks on their faces, by for example by printing conductive ink or adding metallic foil.

Figure 1 shows two identical elementary windings 1 and 2 united in a multiple winding. Each of the windings is formed by a nested primary winding and a secondary winding, each being partially produced on each of the upper and lower faces, of the support on which this elementary winding is formed.

The primary winding, for example, is formed of a first section conductor 3 extending approximately 360 ° around the winding axis, for form a first turn on the upper face of the support, and a second conductive section 4 also extending approximately 360 ° around the axis of the winding, to form a second turn on the underside of the support. In the same way, the secondary winding is formed of a first conductive section 5 extending approximately 360 ° around the axis of the winding, to form a first turn on the upper face of the support, and a second conductive section 6 also extending approximately over 360 ° around the winding axis, to form a second turn on the face support.

The various aforementioned sections, and therefore the resulting turns, do not are not circular but substantially helical, so that the first turns of each winding are nested on the face upper of the support, as well as the second turns on its face lower. In the present case where each winding has only one turn per side, this means that each turn of each winding passes between the ends of the turn of the other winding formed on the same face of the support.

Furthermore, each turn has a free end which will be described below the connection.

The other end of each turn of each winding is located, on one side of the support, facing the other end of the turn of the same winding, on the other side of the support. These opposite ends are connected by conductive holes 7 (Figure 2) to ensure continuity of each winding from one of its free ends to the other.

It will be observed, and more particularly in FIG. 3, that the turns of each winding have shapes such that they spare 8 overlapping recesses. The conductive holes of the other winding pass through these indentations, which ensures recovery optimal primary and secondary windings, and therefore good magnetic performance.

The free ends of the primary winding are connected to two connecting conductors 9 and 10 (here, double), perpendicular to the plane of the support and arranged side by side. Likewise, the free ends of the secondary winding are connected to two connecting conductors similar 11 and 12 (one of which, here, is double). The connecting conductors of the primary and secondary are carried out in a known manner in the form of conductive holes, when assembling the superimposed supports.

The primary windings on the one hand, and the windings secondary on the other hand, coils 1 and 2 are here connected in parallel. Figure 4 shows however a multiple winding, primary or secondary, where three elementary windings are connected in series on four conductive holes 13a-13d. The arrangement of Figure 4 does not differ not otherwise than that of FIG. 1 and will therefore not be described further in detail.

We will have noticed that all the conductive sections represented so far the drawings are split. This is a provision known related to the fact that the current is not uniformly distributed over a given conductor going from the axis of the coil to the outside. Each winding is therefore divided into two conductors, each of these conductors passing inside on one side of the support and outside on the other side, which optimizes the AC resistances by forcing the same current in both branches.

We will now refer to Figure 5 (in which only one of the windings is split as described in the previous paragraph). The primary winding (for example) 20 and the connections of the windings at the conductive holes 21a-21d are identical to those of the Figure 1. We will therefore only describe the secondary winding 22.

This consists of six helical sections, each extending over substantially 360 °, thus forming six turns, three on one side of the support and three on the other side. The first turn 22a extends over the upper face of the support from the conductive hole 21c, outside the winding, up to inside the winding. The winding then continues through a hole conductor 23a, where it passes through the support. The second turn 22b extends so on the underside of the support, from the conductive hole 23a to another conductive hole 23b, near the conductive hole 21c. The third turn 22c extends again to the upper face, inside of the turn 22a, from the conductive hole 23b to the conductive hole 23c at near the conductive hole 23a. The winding thus continues in series by the turn 22d, the conductive hole 23d, the turn 22e, the conductive hole 23e, and the turn 22f, connected to the conductive hole 21d.

We observe that the three turns 22a, 22c and 22e of the winding secondary 22 carried by the upper face of the support, are arranged side by side in the same area reserved so to speak for winding secondary 22. This spiral-shaped area is nested with another also spiral-shaped area, which is it, reserved for the coil split 20b of the primary winding 20. We also find, on the other side of the support, this same arrangement of turns in two zones in form of interlocking spirals, one reserved for the turns of the winding primary and the other to the turns of the secondary winding. This provision allows, as we have just seen, to make primary windings and secondary with different numbers of turns, here a winding primary with a split coil and a secondary winding with six single turns using only a two-sided support. She permits also better use of copper because the distances isolation to be respected within each zone are less because it it is only an interspire isolation within the same winding.

The winding which has just been described relative to FIG. 5, can obviously be associated with others in parallel or in series, as with Figures 1 or 4 respectively.

Claims (8)

1. Coil for planar transformer comprising at least one primary winding and at least one secondary winding, of the type whose primary winding (3, 4; 20a, 20b) and secondary winding (5, 6; 22a-22f) comprise turns made in the form of conductive tracks formed on the faces of an insulating support and connected together by means of conductive ' holes (7,23a-23e) drilled in the insulating support, characterized in that the portions of the primary and secondary windings (20a resp. 22a, 22c, 22e; 20b resp. 22b, 22d, 22f) carried by one and the same face of the insulating support are grouped together on a per-winding basis, according to two separate nested zones, of spiral shape, one of the zones grouping together, side by side, turns or portions of turns (20a or 20b) of the primary winding and the other zone grouping together, side by side, turns or portions of turns (22a, 22c, 22e or 22b, 22d, 22f) of the secondary winding.
2. Coil according to Claim 1, characterized in that each winding portion carried by a face of the insulating support forms a turn which extends over approximately 360°.
3. Coil according to any one of Claims 1 and 2, characterized in that one at least of the windings (22a-22f) is formed on each face of the support of a plurality of winding portions joined successively from one face to the other of the support, in series by the said conductive holes (23a-23e).
4. Coil according to Claim 1, characterized in that the turns of each winding have shapes such that they create superposed indentations (8) through which the conductive holes of the other winding pass.
5. Multiple coil for planar transformer, characterized in that it comprises a plurality of coils (1, 2) according to any one of Claims 1 to 4, arranged one above another on a plurality of assembled supports and connected together electrically within one and the same primary or secondary winding by conducting holes drilled through the assembled supports.
6. Coil according to Claim 5, characterized in that the said windings are linked in series.
7. Coil according to Claim 5, characterized in that the said windings are linked in parallel.
8. Coil according to any one of Claims 5 to 7, characterized in that it comprises at least several primary coils or several secondary coils.

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