FR3058589A1 - ELECTROMAGNETIC ACTUATOR WITH AXIAL FLUX AND AUXILIARY SERIES OF WINDING - Google Patents

Abstract

The present invention relates to an axial flow electromagnetic actuator (1) which comprises on at least one stator (2, 2a) with at least one auxiliary series (3) of coils and a first series (3a) of coils (10). The first series and the auxiliary series (3) form concentric arcs. A rotor (5) has a pivot axis (7) with respect to the stator (2, 2a) disposed at its lower portion and at least two sets (8, 8a) of permanent magnets (9), the pivot axis (7) passing through the common center (6) of circular arcs. The series (8, 8a) of permanent magnets (9) of the rotor (5) are arranged in respective circular arcs, each series (8, 8a) of permanent magnets (9) being opposite the first series (3a) or auxiliary series (3) forming a respective gap (4) with its series of coils (10) associated.

Description

® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number: 3,058,589 (to be used only for reproduction orders) © National registration number: 16,01592

COURBEVOIE © Int Cl ⁸ : H 02 K26 / 00 (2017.01), H 02 K 16/00, H 01 F 7/14

A1 PATENT APPLICATION

©) Date of filing: 08.11.16. (© Priority: © Applicant (s): WHYLOT SAS - FR. ®) Date of public availability of the request: 11.05.18 Bulletin 18/19. @ Inventor (s): MIHAILA VASILE and RAVAUD ROMAN. ©) List of documents cited in the preliminary search report: See the end of this booklet (© References to other related national documents: ® Holder (s): WHYLOT SAS. ©) Extension request (s): © Agent (s): WHYLOT.

ELECTROMAGNETIC ACTUATOR WITH AXIAL FLOW AND AUXILIARY WINDING SERIES.

FR 3 058 589 - A1 (b / d The present invention relates to an electromagnetic actuator (1) with axial flux which comprises on at least one stator (2, 2a) with at least one auxiliary series (3) of windings and a first series (3a) of windings (10). The first series and the auxiliary series (3) form concentric arcs of a circle. A rotor (5) has a pivot axis (7) relative to the stator (2, 2a) arranged at its lower portion and at least two series (8, 8a) of permanent magnets (9), the pivot axis (7) passing through the common center (6) of the arcs of a circle. permanent magnets (9) of the rotor (5) are arranged in respective arcs of a circle, each series (8, 8a) of permanent magnets (9) being opposite the first series (3a) or the auxiliary series (3) by forming a respective air gap (4) with its associated series of windings (10).

10 15 14

Electromagnetic axial flow actuator and auxiliary winding series

The present invention relates to an electromagnetic actuator with axial flow, at least one air gap, direct drive and with an angular operating range. The actuator has at least one stator and at least one rotor. The stator (s) comprise a first series of windings and the rotor (s) are pivotable relative to the stator (s) and carry permanent magnets.

Such an electromagnetic actuator can be used as a joystick, either for industrial purposes or for recreational purposes, for example by being part of a game console.

In the nonlimiting case of an electromagnetic actuator serving as a control handle for a transport element, a particular problem is posed by the safety of the actuation of certain components, this more particularly in an airplane. What is called a redundancy of the supply or actuation means of certain components is carried out.

Redundancy is one of the solutions envisaged for compensating for any failure in the functioning of a system, thus providing protection for the functioning of the system, termed "fault tolerance". The principle of redundancy lies in the duplication or multiplication of certain components, components, functions, subsystems, or even of the system itself, in order to perform a given mission in the presence of failures.

In the specific case of electromagnetic actuators, this leads to the multiplication of actuators dedicated to a function. It is therefore planned to double, triple or even quadruple the electric actuators for the same function. These actuators take up space and this is particularly disadvantageous for a means of transport which is characterized by a lack of endemic space for all the elements mounted on board, these elements having to take up the least possible space.

In addition, the presence of several electric actuators for the same function increases the weight of the actuation assembly, which is also particularly disadvantageous for a means of transport.

It was proposed by document WO-A-2015/004341 to use an electromagnetic actuator with multiple air gaps and with an angular operating range with at least three magnet elements arranged at a distance from each other and each comprising a series of permanent magnets. A winding element carrying at least one winding is framed between each pair of successive magnet elements, an air gap being defined between each of said magnet elements and the winding element thus framed.

In this document, it is proposed that the supply of each winding element or of a group of winding elements is specific to the element or of the group respectively and that the support means of each winding element does not contain of iron. On the other hand, the electromagnetic actuator described in this document is an electromagnetic radial flux actuator.

The purpose of having winding elements not comprising iron, the iron can be constituted by the winding support means or a central iron core for channeling the magnetic field passing through the winding element is, d on the one hand, to lighten the weight of electromagnetic actuators.

On the other hand, and above all, the presence of iron has the disadvantage for the electromagnetic actuator to have, when de-energized, a residual torque called the trigger torque.

This expansion torque, also called cogging torque in English, is due to the magnetic interaction between the permanent magnets of the element or elements with permanent magnets, forming for example the rotor or rotors, and the iron present in the or winding elements, forming for example the stator (s), the iron being frequently used for making the notches of the winding support means. This torque is undesirable for the proper functioning of each electromagnetic actuator.

Finally, a final disadvantage of the presence of iron in the element or the winding elements of an electromagnetic actuator is to create what is called iron losses. These iron losses can be of two types. The first type concerns hysteresis losses due to the permanent magnetization of the magnetic path. The second type concerns the eddy current losses produced by the rotating magnetic field.

These losses lead to overheating of the entire electromagnetic actuator as well as to losses of torque due to a lower current intensity available for the operation of the actuator, this in particular at high operating speeds.

The electromagnetic actuator proposed in document WO-A2015 / 004341 is a radial flux actuator. However, such an actuator does not make it possible to respond to major constraints such as the reduction in mass and the size of the motor for optimal efficiency of the electromagnetic actuator.

Such an electromagnetic actuator is required to have variable output powers. This leads to oversizing of the series of windings as well as the series of permanent magnets.

The problem underlying the present invention is to design an electromagnetic actuator with at least one air gap, with direct drive and with an angular operating range, which can have, on the one hand, a large modulation of power delivered by the actuator by varying the torque and, on the other hand, ensuring redundancy of the stator winding elements.

To this end, the present invention relates to an electromagnetic actuator with at least one air gap, with direct drive and with an angular operating range, this actuator comprising at least one stator and at least one rotor, said at least one stator comprising a first series of windings and said at least one rotor pivoting relative to said at least one stator and carrying permanent magnets, characterized in that the actuator is of axial flux and that it comprises on said at least one stator at least one auxiliary series of windings , the first series of windings and said at least one auxiliary series of windings each forming an arc of a circle, the circular arcs of the first series and of said at least one auxiliary series of windings being concentric, the rotor having a pivot axis with respect to said at least one stator disposed at a lower portion of the rotor and at least two sets of permanent magnets, the pivot axis passing through the common center of s circular arcs of the first series and of said at least one auxiliary series of windings, said at least two series of permanent magnets of the rotor being arranged in respective arcs of circle, each series of permanent magnets being opposite each other screw of the first series of windings or of said at least one auxiliary series of windings by forming a respective air gap with its associated series of windings.

The technical effect obtained by the present invention is to have one or more auxiliary series of windings on the or one of the stators of the electromagnetic actuator. This auxiliary series of windings can be supplied electrically permanently or not. When there are several auxiliary series, these auxiliary series can be fed independently of each other.

It may for example be possible to electrically supply the auxiliary series or series to increase the torque supplied by the actuator, in which case there is no replacement of the first series of windings by the auxiliary series or series.

Alternatively, it is possible to leave one or more of the auxiliary series not supplied with power while the actuator is operating. This or these series can then be used for redundancy.

In the specific and non-limiting case of redundancy for failure of at least one of the stators requiring, according to the state of the art, several motors, the present invention uses only an axial flow actuator and therefore a space requirement less than several actuators with their respective carcasses taking up space.

In general, the present invention allows a modulation of the power and a distribution of the work load on different parts of the same actuator. While in the prior art, apart from a case of redundancy, a single actuator is used with a single stator and rotor, the present invention makes it possible to use at least one actuator but with several series of windings on one same stator. There are therefore more possibilities for modulating the torque supplied by the actuator than those proposed by the state of the art.

Advantageously, the actuator is supplied with polyphase current, each winding of the first series of windings having winding groups supplied respectively by a phase of the current, each winding being mounted on a tooth or on several teeth respectively without overlapping or with overlapping between the windings supplied by a different respective phase.

This can allow redundancy of the first series of windings by windings incorporated in the first series.

Advantageously, the actuator comprises a control unit comprising means for detecting a failure on the first series of windings or on said at least one stator, a redundancy action being provided either by:

means for closing a switch controlled by the control unit, the switch electrically supplying said at least one auxiliary series of windings as soon as the detection means have signaled a failure of the first series of windings, a derivation of the first series of faulty windings being effective when the first series of windings is electrically connected in series with said at least one auxiliary series of windings, or

- when a first group of windings of the first series of windings supplied by its own supply phase is detected as being faulty, at least a second group of windings of the first series of windings, previously de-energized, is switched off energized by being supplied by another phase, the control unit controlling means for closing a switch for energizing said at least one second group of windings, the switch electrically supplying said at least one second group as well as means for opening the switch when the first group is supplied.

Two types of redundancy can be proposed by the present invention, a redundancy made by windings incorporated in the first series of windings and a redundancy carried out by the auxiliary series or windings. These redundancies can be done as an alternative or in combination.

Advantageously, the redundancy is carried out by said at least one auxiliary series of windings and at least a second group of the first series of windings.

Advantageously, when each winding is mounted on a tooth, an association of the shapes of permanent magnets and / or of the shapes of teeth of the windings of said at least one stator carrying the series of windings makes it possible to reduce an expansion torque and a variation in torque .

Advantageously, the first series of windings and said at least one auxiliary series of windings have an offset between them to reduce the expansion torque and the torque variation. Having an offset can mean in one of the embodiments of the present invention that the radial ends of the coils of the first series are not aligned on the same radius with the radial ends of at least one auxiliary series of coils.

Advantageously, the teeth of the same series of windings are similar or of different shape.

Advantageously, the permanent magnets of said at least two sets of permanent magnets are in the form of polygonal tiles.

Advantageously, the permanent magnets of said at least two series of permanent magnets are chosen from ferrite magnets, magnets based on rare earths such as neodymium-iron-boron magnets or samarium cobalt magnets, magnets based on aluminum, nickel and cobalt, with or without thermoplastic binder.

Advantageously, the first series of windings and said at least one auxiliary series of windings are mounted in series or in parallel.

Advantageously, said at least one auxiliary series of windings is supplied separately from the first series of windings.

Advantageously, the actuator comprises at least two stators and at least one rotor.

Advantageously, said at least one rotor is of substantially triangular shape, an apex of the triangle forming the base carrying the common center of the arcs of a circle of the first series of windings and of said at least one auxiliary series of windings and the pivot axis. , the two other vertices being joined by a connection portion substantially in an arc of an outer circle concentric with the first series of windings and said at least one auxiliary series of windings, a control member being carried by the longitudinal middle part of the portion of connection.

The electromagnetic actuator comprises a casing enveloping said at least one stator and said at least one rotor and, when said at least one rotor carries a control member projecting out of the casing of the electromagnetic actuator, the casing has a groove for a passage of a portion of the control member, the groove being arranged so that the control member slides along the groove.

The electromagnetic actuator is used as a control handle.

Other characteristics, objects and advantages of the present invention will appear on reading the detailed description which follows and with regard to the appended drawings given by way of nonlimiting examples and in which;

- Figure 1 is a schematic representation of a cross section of a first embodiment of an electromagnetic actuator comprising two stators surrounding a rotor and a casing enveloping the whole, the casing being shown transparent in this figure, the actuator electromagnetic being according to the present invention with the two stators each comprising an auxiliary series of windings,

FIG. 2 is a schematic representation of a perspective view of the electromagnetic actuator of FIG. 1, the electromagnetic actuator having a control lever projecting from the casing,

- Figure 3 is a schematic representation of a view similar to Figure 2 except that the housing is made transparent to allow the elements to be seen inside,

- Figure 4 is similar to Figure 3, however showing the rotor removed between the two stators to reveal two sets of permanent magnets carried by the rotor,

- Figure 5 is an exploded view of an electromagnetic actuator according to the present invention.

It should be borne in mind that the figures are given by way of examples and are not limitative of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily at the scale of practical applications. In what follows, reference is made to all the figures taken in combination. When reference is made to one or more specific figures, these figures are to be taken in combination with the other figures for the recognition of the designated numerical references.

In the figures, although an electromagnetic actuator with two stators and a rotor is shown, this is not limiting, the electromagnetic actuator possibly comprising, for example, a stator and a rotor, two rotors and a stator or several associated rotors with several stators.

Referring to all the figures, the present invention relates to an electromagnetic actuator 1 with at least one air gap 4, with direct drive and with an angular operating range. Such an electromagnetic actuator 1 comprises at least one stator and at least one rotor, in the figures two stators 2, 2a with a rotor 5 interposed between the two stators 2, 2a but this is not limiting. Such an electromagnetic actuator 1 can be used as a joystick for games or industrial applications, in particular in a means of transport.

The stator (s) 2, 2a comprise a first series 3a of windings 10 and the rotor (s) 5 are pivotable relative to the stators 2, 2a and carry permanent magnets 9 of which only one is referenced in FIG. 4.

According to the invention, the actuator 1 is of axial flow and comprises on the stator (s) 2, 2a that it carries at least one auxiliary series 3 of windings. The first series 3a of windings 10 and the auxiliary series or series 3 of windings 10 each form an arc of a circle. The arcs of the first series 3a and of the auxiliary series or series 3 of windings 10 are concentric.

The rotor 5 has a pivot axis 7 relative to the stators 2, 2a disposed at a lower portion of the rotor 5 and at least two series 8, 8a of permanent magnets 9. The pivot axis 7 is coincident with the common center 6 of the circular arcs of the first series 3a and of the auxiliary series or series 3 of windings.

The two series 8, 8a of permanent magnets 9 of the rotor 5 are arranged in respective arcs of a circle. Each series 8, 8a of permanent magnets 9 is opposite a first series 3a of coils 10 or an auxiliary series 3 of coils 10 by forming a respective air gap 4 with its series of coils 10 associated.

In the figures, the first series 3a of coils 10 is more internal to the electromagnetic actuator 1 than the auxiliary series 3 of coils 10 which is itself the most external. This is not limiting.

In the figures, only a magnet element is referenced 9. Likewise, only a winding element is referenced 10. These references are however valid for all the respective elements.

In the figures, without being limiting, the arc formed by the most internal series of magnets 8a comprises four magnets 9 like the arc formed by the most external series of magnets 8. The first series 3a of coils comprises nine windings 10 as the auxiliary series 3 of windings. The numbers given of magnets 9 and of coils 10 are not, however, limiting.

The length of a circular arc formed by a series 3, 3a of winding 10 can be greater than that of the circular arc of a series 8, 8a of permanent magnets 9, this to allow their rotation in the angular operating range of the actuator 1. The magnets 9 can thus be located opposite at least one winding element 10 during the rotation of the actuator 1 in its angular range. This is not limiting.

It follows that the winding elements 10 and the magnets 9 do not make a complete revolution in the actuator 1, these arcs being limited as a function of the angular operating range of the actuator 1. This range can be arbitrary by example between a few degrees and less than 360 °, for example +/- 15 ° which is not limiting.

The permanent magnets 9 have a spacing between them which does not necessarily correspond to the spacing between the windings 10 of the series 3, 3a of associated windings 10. The angle at the top of the series of coils 10 can be greater than the angle at the top of an arc formed by a series 8, 8a of permanent magnets 9.

In a preferred embodiment of the present invention, the actuator 1 can be supplied with polyphase current. Each winding 10 of the first series 3a of windings 10 can have winding groups 10 supplied respectively by a phase of the current. Each winding 10 can be mounted on a tooth 11 or on several teeth 11 respectively without overlapping or with overlapping between the windings 10 supplied by a respective respective phase. This is particularly useful for performing redundancy as will be described below. This can also apply to the or at least one of the auxiliary series 3 of windings.

To ensure redundancy, the electromagnetic actuator 1 may comprise a control unit comprising means for detecting a failure on the first series 3a of windings 10 or on said at least one stator 2, 2a.

A redundancy action is then provided either by means of closing a switch controlled by the control unit, the switch electrically supplying the auxiliary series or series 3 of windings 10 as soon as the detection means have signaled a failure of the first series 3a of windings.

A derivation of the first series 3a of faulty windings 10 being effective when the first series 3a of windings 10 is electrically connected in series with the auxiliary series or series 3 of windings.

As an alternative or in addition to this redundancy action, another redundancy action can be provided, when a first group of windings 10 of the first series 3a of windings 10 supplied by a supply phase of its own is detected as being in failure, by at least a second group of windings 10 of the first series 3a of windings, previously de-energized.

This second group is energized by being supplied by another phase, the control unit controlling means for closing a switch for energizing said at least one second group of windings, the switch electrically supplying said at least a second group as well as means for opening the switch when the first group is supplied.

It is possible to implement the two previously mentioned redundancy actions, the redundancy being effected by the auxiliary series or series 3 of windings 10 and at least a second group of the first series 3a of windings.

In the context of the present invention, the electromagnetic actuator 1 can however be configured so as not to effect redundancy, the auxiliary series or series 3 of windings 10 being able to serve to increase the power delivered by the electromagnetic actuator 1 by being set series or in parallel with the first series 3a of windings 10 of the stator 2, 2a or of one or more stators 2, 2a when the electromagnetic actuator 1 includes them.

Another object of the present invention is to reduce the trigger torque. This is ensured, when each winding 10 is mounted on a tooth, by a combination of the shapes of permanent magnets 9 and / or the shapes of teeth 11 of the windings 10 of the stator (s) 2, 2a carrying the series of windings 10 making it possible to reduce an expansion torque and a torque variation.

This can for example be carried out because the first series 3a of windings 10 and the auxiliary series or series 3 of windings 10 have an offset between them to reduce the expansion torque and the variation in torque. This can be done by intervals between the windings 10 of the auxiliary series or series 3 not angularly aligned with the respective intervals of the first series 3a of windings. The teeth 11 of the same series of coils 10 may be similar or of different shape.

The permanent magnets 9 of said at least two series 8, 8a of permanent magnets 9 can be in the form of polygonal tiles. In the figures, the polygonal tiles are in the form of quadrilaterals, which is not limiting.

The permanent magnets 9 of the series 8, 8a of permanent magnets can be chosen from ferrite magnets, magnets based on rare earths such as neodymium-iron-boron magnets or samarium cobalt magnets, magnets based on aluminum, nickel and cobalt, with or without thermoplastic binder.

In an alternative embodiment, at least one of the series 8, 8a of permanent magnets 9 can have their adjacent magnets mounted according to a Halbach structure. It is also possible to combine a Halbach structure for at least one of the magnets 9 of the actuator 1 with a magnet structure mounted with their reverse polarity for other magnets 9 of the same actuator 1.

A Halbach structure consists of a particular arrangement of permanent magnets 9 which makes it possible to increase the magnetic field on one side of the series 8, 8a of permanent magnets 9 while the magnetic field on the other side of the series is significantly reduced or even canceled.

This is obtained by having a specific pattern of arrangement of the permanent magnets 9. Such an arrangement is advantageous for the innermost or outermost magnet element of the actuator 1, the winding element 10 interposed between these two magnets 9 most internal or most external being traversed by a magnetic field then concentrated in the space between the two magnets 9 most internal or most external framing this winding element.

Thus, it can advantageously be provided at least one permanent magnet element 9 the most internal or the most external to the actuator 1, the magnets of said at least one permanent magnet element 9 being mounted according to a Halbach structure and establishing a field increased magnetic on the side facing the associated winding element 10, while the magnetic field is reduced or canceled on its side opposite to the winding element. This reduces the loss of the magnetic field.

For their electrical supply, the first series 3a of coils 10 and the auxiliary series or series 3 of coils 10 can be mounted in series or in parallel.

At least to ensure redundancy or a variation in torque, the auxiliary series or series 3 of windings 10 can be supplied separately from the first series 3a of windings.

The rotor (s) 5 can be of substantially triangular shape. A vertex of the triangle, at an angle referenced a in FIGS. 1 and 4, forms the base carrying the common center 6 of the arcs of a circle of the first series 3a of windings 10 and of the auxiliary series or series 3 of windings 10 and l pivot axis 7.

In FIG. 4, the angle at the top of the triangle a is to be compared with the angles a2 and a3 respectively designating the arc of a circle of the auxiliary series 3 of windings and the arc of a circle of the first series 3 of coils which are larger without necessarily being both.

As it is particularly clearly visible in FIGS. 3 and 4, the two other vertices can be joined by a connection portion 12 substantially in an arc of an outer circle concentric with the first series 3a of windings 10 and the auxiliary series or series 3 of windings.

A control member 13 can be carried by a longitudinal middle part of the connection portion 12. This control member 13 can include a handle 16 for gripping the control member 13 by a user.

As can be seen in particular in FIGS. 1 to 3, the electromagnetic actuator 1 can comprise a casing 14 enveloping the stator (s) 2, 2a and the rotor (s) 5. When the rotor (s) 5 carry a protruding control member 13 outside the casing 14 of the electromagnetic actuator 1, the casing 14 has a groove 15 for a passage of a portion of the control member 13, the groove 15 being arranged so that the control member 13 slides along groove 15.

It may be possible to carry out an additional hooping operation on the magnets placed in a respective housing, but this operation can be reduced compared to a hooping operation known from the state of the art. The housings are advantageously obtained by machining the permanent magnets 9. This is not limiting.

When there are several rotors, there may be a mechanical means of coupling and uncoupling the rotors of a common shaft. This possibility makes it possible to solve a problem occurring with a rotor in one of the motors, for example a magnet separation.

Advantageously, also for all the embodiments of the invention, for the electromagnetic actuator 1, the windings 10 can be covered with a protective hoop at least on one or sides facing respectively towards the series 8, 8a of permanent magnets 9. This protective hoop can advantageously be formed by a heat-shrinkable tape, for example a layup of composite material based on glass fibers, without this being limiting.

For all the described embodiments of the present invention, the coils 10 can be conventional coils consisting of a good conductive metal wire wound on a support means, this support means being able to have teeth 11 spacing the coils 10 or helping to their positioning.

The winding (s) 10 are advantageously made of copper or aluminum wire. The support means is based on a material that does not contain iron and is, for example, plastic, composite, glass. This support means can advantageously be flexible and elastically deformable.

Claims (15)

1. Electromagnetic actuator (1) with at least one air gap (4), with direct drive and with an angular operating range, this actuator (1) comprising at least one stator (2, 2a) and at least one rotor (5), said at least one stator (2, 2a) comprising a first series (3a) of windings (10) and said at least one rotor (5) pivoting relative to said at least one stator (2, 2a) and carrying permanent magnets ( 9), characterized in that the actuator (1) is axial flow and that it comprises on said at least one stator (2, 2a) at least one auxiliary series (3) of windings, the first series (3a) of windings (10) and said at least one auxiliary series (3) of windings (10) each forming an arc of a circle, the arcs of circle of the first series (3a) and of said at least one auxiliary series (3) of windings (10) being concentric, the rotor (5) having a pivot axis (7) relative to said at least one stator (2, 2a) disposed at a lower portion of the rotor (5) and at least ux series (8, 8a) of permanent magnets (9), the pivot axis (7) passing through the common center (6) of the arcs of the first series (3a) and said at least one auxiliary series (3) of windings, said at least two series (8, 8a) of permanent magnets (9) of the rotor (5) being arranged in respective arcs of circle, each series (8, 8a) of permanent magnets (9) being opposite the first series (3a) of windings (10) or said at least one auxiliary series (3) of windings (10) by forming a gap (4) respective with its series of windings (10 ) associated. 2. electromagnetic actuator (1) according to the preceding claim, which is supplied with polyphase current, each winding (10) of the first series (3a) of windings (10) having winding groups (10) supplied respectively by a phase of the current, each winding (10) being mounted on a tooth (11) or on several teeth respectively without overlapping or with overlapping between the windings (10) supplied by a respective respective phase. 3. electromagnetic actuator (1) according to the preceding claim, which comprises a control unit comprising means for detecting a failure on the first series (3a) of windings (10) or on said at least one stator (2, 2a ), a redundancy action being provided either by: - means for closing a switch controlled by the control unit, the switch electrically supplying said at least one auxiliary series (3) of windings (10) as soon as the detection means have signaled a failure of the first series (3a) of windings, a derivation of the first series (3a) of failed windings (10) being effective when the first series (3a) of windings (10) is electrically connected in series with said at least one auxiliary series (3 ) windings, or - when a first group of windings (10) of the first series (3a) of windings (10) supplied by a supply phase of its own is detected as being faulty, at least a second group of windings (10) of the first series (3a) of windings, previously de-energized, is energized by being supplied by another phase, the control unit controlling means for closing a switch for energizing said at least one second group of windings, the switch electrically supplying said at least a second group as well as means for opening the switch when the first group is supplied. 4. An electromagnetic actuator (1) according to the preceding claim, wherein the redundancy is effected by said at least one auxiliary series (3) of windings (10) and at least a second group of the first series (3a) of windings. 5. An electromagnetic actuator (1) according to any one of the preceding claims, in which each winding (10) is mounted on a tooth. 6. An electromagnetic actuator (1) according to the preceding claim, wherein the first series (3a) of coils (10) and said at least one auxiliary series (3) of coils (10) have an offset therebetween. 7. An electromagnetic actuator (1) according to any one of the two preceding claims, in which the teeth (11) of the same series of coils (10) are similar or of different shape. 8. An electromagnetic actuator (1) according to any one of the preceding claims, in which the permanent magnets (9) of said at least two series (8, 8a) of permanent magnets (9) are under 10 the shape of polygonal tiles. 9. electromagnetic actuator (1) according to any one of the preceding claims, in which the permanent magnets (9) of said at least two series (8, 8a) of permanent magnets (9) are chosen from ferrite magnets, magnets based on rare earths 15 such as neodymium-iron-boron magnets or samarium cobalt magnets, magnets based on aluminum, nickel and cobalt, with or without a thermoplastic binder. · >> 10. An electromagnetic actuator (1) according to any one of claims 1 to 9, in which the first series (3a) of coils (10) 20 and said at least one auxiliary series (3) of windings (10) are mounted in series or in parallel. 11. An electromagnetic actuator (1) according to any one of claims 1 to 9, in which said at least one auxiliary series (3) of coils (10) is supplied separately from the first series (3a) of 25 windings. 12. An electromagnetic actuator (1) according to any one of the preceding claims, which comprises at least two stators (2, 2a) and at least one rotor (5). 13. An electromagnetic actuator (1) according to any one of the preceding claims, in which said at least one rotor (5) is of substantially triangular shape, an apex of the triangle forming the base carrying the common center (6) of the arcs of circle of the first series (3a) of windings (10) and of said at least one auxiliary series (3) of windings (10) and the pivot axis (7), the two other vertices being joined by a connection portion (12) substantially in an arc 5 exterior concentric with the first series (3a) of windings (10) and said at least one auxiliary series (3) of windings, a control member (13) being carried by the longitudinal middle part of the connection portion (12) . 14. Electromagnetic actuator (1) according to any one of 10 preceding claims, which comprises a casing (14) enveloping said at least one stator (2, 2a) and said at least one rotor (5) and, when said at least one rotor (5) carries a control member (13) protruding from the casing (14) of the electromagnetic actuator (1), the casing (14) has a groove (15) for a passage of a portion of the 15 control (13), the groove (15) being arranged so that the control member (13) slides along the groove (15). 15. An electromagnetic actuator (1) according to any one of the preceding claims, which is used as a control lever. 1/5