Winding, inductive filter and transformer with integrated filtering

Abstract

The invention relates to a coil configured to pass an electric current between two main connection points, the device comprising:-a magnetic core (12); -a main electrical conductor (14) in the form of a first flat strip extending between two ends, each end being equipped with one of the main connection points (14c, 14d), and wound around the magnetic core (12) so as to form an inductor; -an auxiliary electrical conductor (20) in the form of a second strip wound together with the main electrical conductor and equipped with an auxiliary connection point (20c); -an electrical insulator (22) separating the main electrical conductor from the auxiliary electrical conductor in order to form a capacitor between the two electrical conductors.

Description

Technical Field

[0001] This invention relates to coils, inductive filters, and transformers for improving filtering against some high-frequency interference.

[0002] This invention is particularly useful in the aviation field, where the current trend is to increase the number of electrical devices and thus increase airborne electrical power. Background Technology

[0003] Aircraft typically include numerous electrical loads powered by an onboard power network. For example, the aircraft's flight controllers, air conditioning, and interior lighting systems utilize three-phase AC motors. The electrical energy supplied to these machines comes from power converters connected to the onboard network, which delivers power in either DC or AC form. The onboard network may include, for example, generators, batteries, or even devices for connecting to external power networks and allowing the aircraft to be powered while parked at an airport. Typically, aircraft have a 540V DC network and / or a 115V or 230V 400 Hz AC network. In a known manner, the power converter receives energy from the onboard network, which is then converted into multiphase AC energy suitable for the power and frequency requirements of the loads.

[0004] Converters typically include transformers that allow AC voltage to be reduced or increased. Static converters incorporating electronic switches have also been found. Inverters that generate AC voltage using pulse-width modulation (PWM) operation can be cited as an example. In addition to various power supply phases, some loads powered by multiphase AC voltages may require the presence of a neutral point. A neutral point can be generated at the inverter output using a specific transformer.

[0005] In a static converter, the chopping frequency is much higher than the frequency of the useful AC voltage generated by the inverter. The presence of this chopping frequency tends to generate high-frequency interference that often propagates on airborne networks. Low-pass filters can be placed at the input or output of the converter to filter out high-frequency interference. These filters can consist of inductors connected in series and capacitors connected in parallel. The presence of transformers also tends to filter out high-frequency interference caused by the inductance in the transformer windings. These transformers typically require additional capacitors connected in parallel.

[0006] In many modes of transportation, and more specifically in aircraft, reducing airborne mass is a frequent challenge. Therefore, the current trend of increasing the number of airborne electrical devices often involves not only increasing the mass of filters required for the proper operation of airborne electrical systems, but also increasing the size of those filters. Summary of the Invention

[0007] The object of this invention is to overcome all or some of the above-mentioned problems by proposing to reduce or even eliminate external capacitors associated with inductors and transformers.

[0008] Therefore, the object of the present invention is a coil configured to transmit current between two main connection points, the device comprising: -Magnetic core; - A first flat strip in the form of a main conductor, the first flat strip extending between two ends, each end being equipped with one of the main connection points, and the main conductor being wound around the magnetic core to form an inductor; - A second auxiliary conductor in the form of a strip, which is wound together with the main conductor and is equipped with a first auxiliary connection point and a second auxiliary connection point; - An electrical insulator that separates the main conductor from the auxiliary conductor to form a capacitor between the two conductors. The electrical conductor extends along a primary axis and a secondary axis, the primary axis extending in a plane perpendicular to the axis of the magnetic core, the secondary axis perpendicular to the primary axis, and wherein the primary electrical conductor and the auxiliary electrical conductor are partially superimposed along the secondary axis.

[0009] Advantageously, the main electrical conductor and the auxiliary electrical conductor are superimposed over their entire length, which is defined along an axis extending in a plane perpendicular to the main axis.

[0010] Advantageously, the main electrical conductor and the auxiliary electrical conductor are partially superimposed along the main axis.

[0011] The first auxiliary connection point may be located at one of the ends of the auxiliary conductor, which is defined along the main axis.

[0012] Alternatively, the first auxiliary connection point may be located between the ends of the auxiliary electrical conductors, which are defined along the main axis.

[0013] The main conductor and the auxiliary conductor (20) may be made of the same or different materials.

[0014] The degree of superposition of two conductors along the secondary axis can vary along the primary axis.

[0015] These electrical conductors can each be U-shaped, and these U-shapes are interlaced.

[0016] The coil may also include a second auxiliary conductor, which is in the form of a strip wound together with the main conductor, and is equipped with a first auxiliary connection point and a second auxiliary connection point.

[0017] The auxiliary electrical conductor may be configured to form a fusible protective section calibrated to not exceed a given current intensity value.

[0018] Another object of the present invention is a transformer comprising at least one coil forming a primary winding of the transformer according to the present invention, and a second primary conductor wound around a magnetic core of the electromagnetic coil and forming a secondary winding of the transformer.

[0019] Another object of the present invention is a component comprising two coils according to the invention, the two coils being wound on the same closed magnetic core. Attached Figure Description

[0020] The invention will be better understood and other advantages will become apparent from the detailed description of the embodiments provided by way of example, which are illustrated in the accompanying drawings, wherein: Figure 1 A perspective view of the coil according to the present invention is shown schematically; Figure 2 schematically shown Figure 1 The cross-section of the coil; Figures 3 to 8 A plan view of the coil's electrical conductors and electrical insulators is shown; Figures 9 to 12 Several variations of the shape of one of the electrical conductors are shown; Figure 13 The variation of the winding of the electrical conductor is shown; Figure 14 A neutral transformer for implementing the present invention is schematically shown; Figure 15 An inductive filter comprising two coils according to the present invention is shown. Detailed Implementation

[0021] For clarity, the same elements will use the same reference numerals in the various figures.

[0022] Figure 1 A perspective view of a coil 10, including a magnetic core 12 and an electrical conductor 14, referred to as the main conductor, is schematically shown. The electrical conductor 14 is wound around the magnetic core 12. In the example shown, the magnetic core 12 is rod-shaped, extending along axis 16. Any other shape of the magnetic core is possible within the scope of this invention. In particular, a closed magnetic core can be achieved to guide magnetic field lines. Such a closed core includes a straight portion extending along axis 16.

[0023] Figure 2 A cross-sectional view of the coil 10 in a plane perpendicular to axis 16 is shown. The main conductor 14 is in the form of a flat strip wound around the magnetic core 12. The main conductor 14 mainly comprises a strip of conductive material formed between two main surfaces 14a and 14b parallel to axis 16.

[0024] The main conductor 14 extends between two main connection points 14c and 14d to form an electrical winding around the magnetic core 12; in fact, each main connection point 14c and 14d is located at one end of the strip. The current flowing in the main conductor 14 generates a magnetic induction in the magnetic core 12 that is primarily oriented along the axis 16.

[0025] The main conductor 14 and the magnetic core 12 form an inductor, which can be used in particular as a filter inductor, either alone or as part of a transformer.

[0026] The coil 10 includes an auxiliary conductor 20 and an electrical insulator 22 separating the main conductor 14 from the auxiliary conductor 20. The auxiliary conductor 20 is in the form of a flat strip wound together with the main conductor 14 to form a capacitor between the two conductors 14 and 20. The auxiliary conductor 20 also mainly comprises a strip of conductive material formed between two main surfaces 20a and 20b, which are also parallel to the axis 16. Similarly, the electrical insulator 22 is in the form of a flat strip wound together with the two conductors 14 and 20. The electrical insulator 22 also mainly comprises a strip of electrical insulating material formed between two main surfaces 22a and 22b, which are parallel to the axis 16.

[0027] In practice, the main conductor 14 forms one of the conductive armatures or electrodes of the capacitor. The auxiliary conductor 20 forms the other electrode of the capacitor. The auxiliary conductor 20 is equipped with an auxiliary connection point 20c that allows the other electrode of the capacitor to be electrically connected.

[0028] Electrical insulator 22 forms the dielectric of the capacitor. Faces 14a face each other 20b and are separated by electrical insulator 22. The capacitor is electrically connected between connection point 20c and one of connection points 14c or 14d.

[0029] This invention allows an inductor formed by a main conductor 14 wound around a magnetic core 12 and a capacitor formed between two conductors 14 and 20 to be combined in the same component. Figure 2 On the magnetic core 12, the main body 14 is wound around the magnetic core 12 to form a turn. In fact, the present invention can achieve a greater number of turns.

[0030] Figures 3 to 8 Plan views of various variations of electrical conductors 14 and 20 and electrical insulator 22 are shown, wherein the surfaces wound around axis 16 are shown in the plane. In other words, in Figures 3 to 8 The electrical conductors 14 and 20, as well as the electrical insulator 22, are shown in superimposed planes around the magnetic core.

[0031] exist Figure 3In this configuration, the surfaces formed by electrical conductors 14 and 20 and electrical insulator 22 are completely superimposed. In other words, the two strips are superimposed over their entire length, which is along... Figure 3 The axis XX, shown as a straight line, is defined and coils around the magnetic core 12 in a plane perpendicular to axis 16. Along the axis YY, which is perpendicular to axis XX and therefore parallel to axis 16, the surfaces formed by the electrical conductors 14 and 20 and the electrical insulator 22 are also completely superimposed. In this completely superimposed structure, the capacitance formed between the two electrical conductors 14 and 20 is the largest.

[0032] The capacitance value formed between the two electrical conductors 14 and 20 can be adapted to the filtering requirements of a system equipped with a coil according to the invention. Figure 4 A variation is shown, in which, apart from the overlapping portion along axis XX (in Figure 4 Except for the partial overlap shown in the variant, the electrical insulator 22-1 and the auxiliary conductor 20-1 are similar to the electrical insulator 22 and the auxiliary conductor 20, respectively. The overlap of the two conductors 14 and 20 is only partial along the YY axis. In other words, the two conductors 14 and 20 are partially superimposed along the YY axis. As an example, Figure 5 An auxiliary conductor 20-2 is shown that overlaps only partially with the main conductor 14 along axis YY. Variations in the degree of overlap can obviously be defined independently along axes XX and YY. For example, complete overlap along axis XX and partial overlap along axis YY can be defined. This simplifies coil fabrication while maintaining strips of equal length along axis XX for both conductors and insulators. The capacitance value is then adjusted by varying the respective widths of the strips, which are defined along axis YY. Figure 5 In the variation shown, the degree of overlap along axis YY is constant along axis XX. The degree of overlap can also be varied along axis XX and along axis YY.

[0033] The variation in overlap along axis YY allows adjustment of the capacitance between the two conductors 14 and 20 without modifying the inductance of the auxiliary conductor 20, which is essentially dependent on the length of the auxiliary conductor 20 along axis XX, which defines the number of turns formed by the auxiliary conductor 20 around the magnetic core 20.

[0034] exist Figure 3 , 4 In the variant shown in 5, the auxiliary conductor is equipped with a single connection point located at one of the ends of the axis XX along the strip forming the auxiliary conductor. Figure 6An alternative is shown in which the auxiliary connection point 20c is located between the ends of the strip forming the auxiliary conductor 20. In other words, a portion of the auxiliary conductor 20 is located on one side of the auxiliary connection point 20c, and another portion of the auxiliary conductor 20 is located on the other side of the auxiliary connection point 20c.

[0035] The main and auxiliary connection points can be created by tabs protruding from the surface of the conductor under consideration along the Y-axis. The tabs can be added and stamped onto the conductor under consideration. Thus, once the conductor is wound around the core 12, the connection point protrudes from the winding and is easily accessible for connecting the coil. This embodiment of the connection point is applicable to any location where the connection point is located along the XX-axis.

[0036] Figure 7 A variation of the coil is shown, wherein, in addition to the connection point 20c located at one end of the strip forming the auxiliary conductor, the auxiliary conductor 20 is also equipped with a second connection point 20d located at the other end of the strip along the axis XX. Besides the capacitance present between the two conductors 14 and 20, the second connection point 20d allows the auxiliary conductor 20 to be used to flow current, as in the main conductor 14. In addition to capacitance, the coil can also be used as a transformer with two windings 14 and 20; in fact, the names "main conductor" and "auxiliary conductor" are interchangeable. By manufacturing the two conductors 14 and 20 from the same material with 100% overlap along axes XX and YY, the difference between the inductance values ​​of the two conductors 14 and 20 is minimized. This variation of the coil is particularly suitable for manufacturing filters that are both inductors and capacitors in common mode. The capacitive and inductive effects are then distributed. The two conductors function similarly to a capacitor and a distributed inductor, with each conductor 14 and 20 acting as an inductor. This allows for the formation of a high-frequency suppression filter, where the inductive and capacitive effects can be independently tuned.

[0037] As an alternative to the connection between the two connection points 20c and 20d, Figure 7 The variant shown also allows for the formulation of a coil that uses only the capacitor between the two conductors 14 and 20, without current flowing through the auxiliary conductor 20, where the connection point 20c or 20d can be selected.

[0038] Figure 8A variation is shown in which two distinct auxiliary conductors 20-3 and 20-4 are present, each forming a different capacitor with the main conductor. Of course, more than two different capacitors can be provided. The two auxiliary conductors 20-3 and 20-4 are each shown with two connection points, 20-3c, 20-3d and 20-4c, 20-4d respectively. Each auxiliary conductor 20-3 and 20-4 may also have only one connection point, which can be located along axis XX at one end of the strip forming the auxiliary conductor under consideration, or between the ends of the strip under consideration. Figure 7 The variant shown, Figure 8 The variation shown can be achieved by flowing current between connection points 20-3c and 20-3d and between connection points 20-4c and 20-4d. Each auxiliary conductor 20-3 and 20-4 can also be connected to only one auxiliary connection point.

[0039] Figure 9 As shown Figure 7 and 8 The partial view shown is of a variant of the auxiliary conductor 20-5 equipped with two auxiliary connection points. The auxiliary conductor 20-5 generally extends along axis XX and is wound around axis XX in order to... Figure 9 An additional inductor is generated between the two auxiliary connection points (not shown). In addition to the capacitance generated between conductors 14 and 20-5, auxiliary conductor 20-5 also generates a first inductance linked to the magnetic core 12 due to its winding around the core 12, and a second inductance not linked to the core 12 due to the meandering shape of auxiliary conductor 20-5 around axis XX. This meandering shape creates variations in the degree of overlap between the two conductors 14 and 20-5 along axis YY and along axis XX.

[0040] Figure 10 , 11 Figures 1 and 12 illustrate other possible examples for changing the degree of overlap between two conductors 14 and 20 along axis YY and along axis XX. More specifically, in Figure 10 In the diagram, the auxiliary conductor 20-6, including the two connection points 20-6c and 20-6d, exhibits a shape where its width along the Y-axis varies sinusoidally along the XX-axis. Figure 11 In the diagram, the auxiliary conductor 20-7, including the two connection points 20-7c and 20-7d, exhibits a shape in which its width along the YY axis varies zigzagly along the XX axis, and in... Figure 12 In the middle, the auxiliary conductor 20-8 exhibits a square shape whose width varies along the axis YY and along the axis XX. Figures 9 to 12The shape of the auxiliary conductor shown is periodic along axis XX. Any other periodic shape is also possible. Auxiliary conductors with non-periodic shapes can also be manufactured. The shape of the main conductor 14 can also be changed, or even the shapes of both conductors can be changed at once.

[0041] Any shape of conductor with angular profiles, such as Figure 11 and 12 The serrated and square shapes shown can create a tip effect in the electric field existing between the two conductors. Conversely, as... Figure 10 The circular shape shown allows these tip effects to be avoided.

[0042] Figure 13 An embodiment of the coil 25 according to the invention is shown, wherein both the main conductor 14-1 and the auxiliary conductor 20-9 are U-shaped along the axis YY. The two U-shapes are staggered. More specifically, one branch of one U-shape is inserted between two branches of the other U-shape. The insulator 22-1 separating the two conductors 14-1 and 20-9 is also folded and wound between the respective U-shaped branches.

[0043] The two conductors 14-1 and 20-9, along with the insulator 22-1, are initially folded into a U-shape and staggered, meaning the axis XX is straight. This staggered assembly is then wound around the magnetic core 12, in other words, as... Figure 1 As shown, axis XX is wound into a spiral around the magnetic core. Figure 13 In this configuration, the interleaved assembly is wound in two layers around the magnetic core 12, and this interleaving allows for an increase in the number of capacitor interfaces per turn of the helix. For example, in... Figure 13 In the middle, the seven capacitor interfaces are presented as a spiral with two turns around axis 16.

[0044] Then, the main conductor 14 is traversed by a current with an intensity greater than that flowing in the auxiliary conductor, particularly when the output phase of the converter flows through the main conductor, and when the auxiliary conductor is equipped with only a single connection point and is used only to generate capacitance.

[0045] The auxiliary conductor, equipped with two connection points, is implemented as a coil to generate a filter for discharging leakage current. During normal operation, the intensity of the current flowing in the auxiliary conductor 20 is significantly lower than the intensity of the current flowing in the main conductor 14, thus allowing the auxiliary conductor to be much thinner than the main conductor. In other words, the dimensions of each of conductors 14 and 20 are designed to withstand the nominal strength passing through it. This dimension can be achieved in the thickness of the conductor, which is defined perpendicular to the axes XX and YY.

[0046] Furthermore, if the current intensity experienced by the auxiliary conductor 20 exceeds a given threshold, it can be calibrated to melt, thereby interrupting the electrical conduction between its two connection points. Therefore, in the event of a failure in a system equipped with such a coil (i.e., a failure that causes excessive current in the auxiliary conductor), the coil is used as a fusible protection component of the system.

[0047] The two electrical conductors 14 and 20 can be made of different materials. For example, the main electrical conductor 14 can be made of a metal, such as aluminum or copper. The auxiliary electrical conductor 20 can also be made of a metal or other conductive materials, such as graphite-based materials in particular. To ensure fusible protection, the auxiliary electrical conductor 20 can be manufactured, for example, by metal vapor deposition on an insulator 22.

[0048] The materials of the two electrical conductors 14 and 20 can be diamagnetic, nonmagnetic, or ferromagnetic. The material types for the two electrical conductors 14 and 20 can be different; for example, they can be fabricated together as an auxiliary conductor 20 and an insulator 22, for example, in the form of a flexible printed circuit. This is as follows: Figures 9 to 12 The schematic diagram is particularly suitable for drawing, for example, the auxiliary conductor 20-5.

[0049] Figure 14 An example of a neutral transformer 30 suitable for the output of a three-phase inverter is shown. In practice, three-phase, or more generally multi-phase, inverters generate three phases u, v, w without a neutral point. In addition to connections to each phase, some multi-phase loads may need to be connected to an electrical neutral potential. Transformer 30 can be connected in parallel to the connections to the loads to the three phases of the inverter. Transformer 30 provides a neutral potential, denoted as N, which is intended to be connected to the load.

[0050] The transformer 30 includes a magnetic core 32, which comprises three branches 32u, 32v, and 32w. As described above, the main conductor 14u and the auxiliary conductor 20u are wound together around branch 32u. Similarly, the main conductor 14v and the auxiliary conductor 20v are wound together around branch 32v. The main conductor 14w and the auxiliary conductor 20w are wound together around branch 32w.

[0051] The first connection point of the main conductor 14u is connected to phase u, the first connection point of the main conductor 14v is connected to phase v, and the first connection point of the main conductor 14w is connected to phase w.

[0052] The second connection point of the main conductor 14u is connected to the input of another winding 34v arranged around branch 32v, the second connection point of the main conductor 14v is connected to the input of another winding 34w arranged around branch 32w, and the second connection point of the main conductor 14w is connected to the input of another winding 34u arranged around branch 32u. The outputs of windings 34u, 34v, and 34w are connected together to form the neutral point N of transformer 30.

[0053] Auxiliary conductors 20u, 20v, and 20w are connected together at one of their connection points via an impedance (e.g., a resistive element R), for example, connected to an electrical ground 36, which may be the neutral point N. For each of the auxiliary conductors 20u, 20v, and 20w, another impedance may be inserted between this connection point and the resistive element R. Figure 14 In the diagram, the auxiliary connection points of auxiliary conductors 20u, 20v, and 20w are shown near the corresponding connection points of the main conductors 14u, 14v, and 14w at the corresponding phases u, v, and w. Alternatively, these auxiliary connection points can be arranged at the other ends of the corresponding auxiliary conductors 20u, 20v, and 20w, as shown below. Figure 7 As shown, and even between the ends, as Figure 6 As shown. Other connection points (not shown to avoid complicating the diagram) of each of the auxiliary conductors 20u, 20v, and 20w can be connected to each other via impedances (more specifically, a first impedance between auxiliary conductors 20u and 20v, a second impedance between auxiliary conductors 20v and 20w, and a third impedance between auxiliary conductors 20w and 20u). Of course, the above connection of auxiliary conductors 20u, 20v, and 20w is merely an example, and auxiliary conductors 20u, 20v, and 20w can be connected at their two connection points in different ways, particularly to attenuate the effects of high-frequency interference.

[0054] More specifically, in Figure 11 In the example shown, the signals for each phase u, v, and w have a first inductor formed by two windings connected in series (e.g., winding 14u and winding 34v for phase u), a second inductor formed by each of auxiliary conductors 20u, 20v, and 20w, and a capacitor connected in parallel (e.g., a capacitor associated with auxiliary conductors 20u, 20v, and 20w). These inductors and the capacitor form a low-pass filter. A resistor R allows filtered high-frequency disturbances to be suppressed.

[0055] like Figure 14As shown, for each phase, transformer 30 includes only one auxiliary conductor associated with each main conductor. In this embodiment, it can also be supplemented by combining auxiliary conductors wound with each winding 34u, 34v, and 34w. The various auxiliary conductors can be connected in various ways, such as in series, in parallel, or by a combination of series and parallel connections.

[0056] An auxiliary conductor shared by two windings of the same branch can also be provided. For example, for branch 32u, the auxiliary conductor can be shared by the main conductor 14u and winding 34u.

[0057] Figure 15 A component 40, which can be implemented as, in particular, a common-mode inductive filter or transformer, is shown. Component 40 includes two coils 10 as described above. Both coils 10 are wound around the same magnetic core 42, which is closed in the illustrated example. Of course, more than two coils 10 can be provided wound around the same magnetic core. This core can be closed or open. As an inductive filter, component 40 is, for example, adapted to filter the output of a rectifier providing a DC voltage supported by a positive phase (+) and a negative phase (-). Each phase flows through the main conductor 14 of each coil 10, and the auxiliary conductor 20 of each coil 10 may, for example, be connected together via a resistive element R to an electrical ground 36. In the absence of auxiliary conductors, it is common practice to combine such a common-mode filter with external capacitors, one per phase, each capacitor connected between the phase in question and the electrical ground of the system in which the filter is integrated. By implementing the present invention, external capacitors can be omitted or at least their value reduced.

Claims

1. A coil configured to transmit current between two main connection points, the device comprising: -Magnetic core (12; 32; 42)； -The first flat strip form of the main electrical conductor (14; 14-1;) 14u, 14v, 14w), which extends between two ends, each end being equipped with one of the main connection points (14c, 14d), and the main electrical conductor is wound around the magnetic core (12; 32; 42) to form an inductor; - A second strip of auxiliary electrical conductor (20; 20-1; 20-2; 20-3; 20-4; 20-5; 20-6; 20-7; 20-8; 20-9; 20u, 20v, 20w) is wound together with the main electrical conductor and is equipped with a first auxiliary connection point (20c) and a second auxiliary connection point (20d; 20-3d); 20-4d)； - An electrical insulator (22; 22-1) separates the main conductor from the auxiliary conductor to form a capacitor between the two conductors. The electrical conductors (14, 20-5; 20-6; 20-7; 20-8) extend along the main axis (XX) and the secondary axis (YY), the main axis (XX) extending in a plane perpendicular to the axis (16) of the magnetic core (12), the secondary axis (YY) perpendicular to the main axis (XX), and wherein the main electrical conductor (14) and the auxiliary electrical conductors (20; 20-1; 20-2) are partially superimposed along the secondary axis (YY).

2. The coil according to claim 1, wherein, The main conductor (14) and the auxiliary conductor (20) are superimposed along their entire length as defined along the main axis (XX).

3. The coil according to claim 1, wherein, The main electrical conductor (14) and the auxiliary electrical conductors (20; 20-1; 20-2) are partially superimposed along the main axis (XX).

4. The coil according to any one of the preceding claims, wherein, The first auxiliary connection point (20c) is located at one of the ends of the auxiliary electrical conductors (20; 20-1; 20-2), the ends being defined along the main axis (XX).

5. The coil according to any one of claims 1 to 3, wherein, The first auxiliary connection point (20c) is located between the ends of the auxiliary conductors (20; 20-1; 20-2), the ends being defined along an axis (XX) extending in a plane perpendicular to the axis (16) of the magnetic core (12).

6. The coil according to any one of the preceding claims, wherein, The main conductor (14) and the auxiliary conductor (20) are made of different materials.

7. The coil according to the preceding claim, wherein, The degree of overlap between the two conductors along the secondary axis (YY) varies along the primary axis (XX).

8. The coil according to any one of the preceding claims, wherein, The electrical conductors (14-1, 20-9) are each U-shaped, and these U-shapes are interleaved.

9. The coil according to any one of the preceding claims further includes a second auxiliary conductor (20-4) in the form of a strip, which is wound together with the main conductor and is equipped with a first auxiliary connection point (20-4c) and a second auxiliary connection point (20-4d).

10. The coil according to any one of the preceding claims, wherein, The auxiliary electrical conductors (20; 20-1; 20-2; 20-3; 20-4; 20-5; 20-6; 20-7; 20-8; 20-9; 20u, 20v, 20w) are configured to form a fusible protective section calibrated to not exceed a given current intensity value.

11. A transformer comprising at least one coil (10) forming a primary winding (14u, 14v, 14w) of the transformer according to any one of the preceding claims, and a second primary conductor (34u, 34v, 34w) of the secondary winding wound around a magnetic core (32) of the electromagnetic coil and forming the transformer (30).

12. A component comprising two coils (10) according to any one of claims 1 to 9, wherein the two coils (10) are wound around the same closed magnetic core (42).

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