WO2015193562A1

WO2015193562A1 - Electromagnetic synchronous motor with combined axial and radial magnetic fluxes

Info

Publication number: WO2015193562A1
Application number: PCT/FR2015/000120
Authority: WO
Inventors: Romain RAVAUD
Original assignee: Whylot Sas
Priority date: 2014-06-20
Filing date: 2015-06-18
Publication date: 2015-12-23
Also published as: FR3022706A1; FR3022706B1

Abstract

The present invention relates to an electromagnetic motor (1) or generator comprising a rotor (2), at least one stator (4), an air gap being defined between the rotor (2) and the stator (4), at least one series of permanent magnets (5) being supported by the rotor (2) and at least one associated series of windings (6) being supported by the stator (4), the series of magnets (5) and the series of windings (6) being positioned so as to create an axial magnetic flux relative to the motor (1) or to the generator, characterised in that the rotor (2) comprises at least one auxiliary series of magnets (7) interacting with an auxiliary series of windings (8) supported by the stator (4), the auxiliary magnetic flux created by the auxiliary series of magnets (7) and windings (8) being a radial magnetic flux.

Description

"Electromagnetic synchronous motor with axial and radial combined magnetic fluxes"

The present invention relates to an electromagnetic synchronous motor with axial and radial combined magnetic flux. More particularly, but not exclusively, this engine is a flat, lightweight engine with very high efficiency.

According to the state of the art, as can be seen in FIG. 1, an example of such a motor 1a consists of at least one rotor 2a forming its rotating element and at least one stator 4a forming its element. fixed. The rotor 2a may comprise at least one series of permanent magnets 5a and the stator 4a may comprise at least one series of coils 6a.

When the series or series of windings 6a are electrically powered, the rotor 2a which is attached to the drive shaft 3a of the motor 1a is subjected to a torque resulting from the magnetic field. Depending on the direction of the magnetic flux created, a motor is referred to as axial, radial or transverse flow. The example of Figure 1 shows a synchronous axial flow motor 1a.

In this embodiment, the or each series of magnets 5a has a thick circular arc shape. The magnets are said to have axial flux because their magnetic field is orthogonal to the plane of the arc of the rotor disc 2a. The center of the circular arc passes through the drive shaft 3a of the motor 1a or the electromagnetic generator.

There are also synchronous motors with radial magnetic flux directed towards the center of the motor and synchronous motors with transverse flux. A transverse flow motor has the following configuration: a stator with a single axial coil with several magnetic circuits, stirrups, orthoradial orientation and overlapping the coil, the rotor retaining its role of looping the magnetic flux but having magnets at the new configuration of stator brackets and coil.

For these three types of synchronous motor, it has also been developed a multi-gap structure that is to say having at least one stator between two rotors or at least one rotor between two stators. In Figure 1, it is this last configuration which is shown with a series of coils 6a of the stator 4a placed on each side of the rotor 2a.

A particular and expanding application for synchronous motors is intended for a flat motor. Such a flat motor or motor wheel is similar to a rotary motor whose stator and the rotor are cut in a plane with a generation of magnetic flux most often axial. The main advantage of this type of engine compared to conventional rotary engines is therefore to have a small footprint.

By generalizing this to any synchronous motor, more and more synchronous motors must fulfill the requirement to have as small a footprint as possible while providing the highest power possible.

WO / 2011059162 discloses an axial flux permanent magnet motor or generator which combines an axial flow mode with a radial flow mode. This motor or generator comprises a first and a second rotor each comprising at least one magnet, said magnets being installed in opposite directions, a first and a second stator each comprising a coil at each end of a core, face to face, said core comprising a fixing unit connected to its central part and fixed to an external anchoring support to interpose between the first rotor and the second rotor.

The engine or generator according to this document also comprises a yoke which is spaced apart from the magnets installed in the first and second rotors and which is connected to the first and second rotors from the inside to form a magnetic flux circuit.

Therefore, such an engine or generator combines the advantages of an axial flow including the minimization of the flow of magnetic leaks and the advantages of a radial flow in terms of excitation effect by a counter-electromotive force. In addition, by having two stators between the magnets, the torque in a given place can be doubled, which gives a motor and a high efficiency generator.

However, it is desirable to simplify the construction of such a motor or generator to reduce its price and its size. US-A-2002/047433 discloses an electromagnetic motor or generator comprising a rotor which is not in the form of a disc integral with a median drive shaft but rather in the form of a cylinder having a housing in its middle longitudinal part. This document also describes at least one stator, an air gap being defined between the rotor and the at least one stator, at least one series of permanent magnets being carried by the rotor and at least one series of associated windings being carried by said at least one a stator, said at least one series of magnets and a series of coils being positioned to create an axial magnetic flux with respect to the motor or generator, the rotor comprising at least one auxiliary series of permanent magnets cooperating with an auxiliary series of respective windings carried by said at least one stator or a portion integral with said at least one stator, the auxiliary magnetic flux created in operation by the auxiliary series of magnets and coils being a radial magnetic flux with respect to the motor or the generator .

However, this document can not be taken as the closest state of the art since, in addition to not showing a rotor in the form of a disc, at least the series of magnets and the series of coils positioned to create an axial magnetic flux with respect to the engine or generator are used to effect axial thrust on the rotor.

The document US-A-2009/001831 describes an electromagnetic motor or generator comprising a rotor in the form of a disk integral with a median drive shaft, at least one stator, an air gap being defined between the rotor and the said rotor. at least one stator, at least one series of permanent magnets being carried by the rotor and at least one series of associated windings being carried by said at least one stator, said at least one series of magnets and a series of coils being positioned for creating an axial magnetic flux with respect to the motor or the generator, the rotor comprising at least one auxiliary series of permanent magnets cooperating with an auxiliary series of respective windings carried by said at least one stator or a portion secured to said at least one stator , the auxiliary magnetic flux created in operation by the auxiliary series of magnets and coils being a radial magnetic flux with respect to the motor or the generator Empress.

Indeed, in this document, the gap is limited to the width of the rotor disc without description or suggestion to increase this gap otherwise than by increasing the width of the disc. Moreover, with such a positioning as provided in this document of the auxiliary series of magnets cooperating with the series of coils of said at least one stator, the auxiliary magnetic flux created in operation by the auxiliary series of magnets and coils for the creation of a radial magnetic flux is necessarily limited to the end portion of the rotor.

The problem underlying the present invention is to design a motor that can combine at least two types of magnetic flux during its operation taken among the axial flow, radial ensuring a high compactness to all while noticeably increasing the torque provided by the motor or being able to allow a high rotational speed of the rotor.

For this purpose, there is provided according to the invention an electromagnetic motor or generator comprising a rotor in the form of a disk secured to a median drive shaft, at least one stator, an air gap being defined between the rotor and said rotor. at least one stator, at least one series of permanent magnets being carried by the rotor and at least one series of associated windings being carried by said at least one stator, said at least one series of magnets and a series of coils being positioned for creating an axial magnetic flux with respect to the motor or the generator, the rotor comprising at least one auxiliary series of permanent magnets cooperating with at least one auxiliary series of respective windings carried by said at least one stator or a portion integral with said at least one a stator, the auxiliary magnetic flux created in operation by the auxiliary series of magnets and coils being a radial magnetic flux with respect to the motor or the generator, characterized in that the rotor comprises an extra thickness carrying said at least one auxiliary series of magnets extending in the length of the excess thickness, said at least one stator bearing at least the auxiliary series of windings vis-à-vis -vis a longitudinal side of the extra thickness, to create the radial magnetic flux with respect to the engine or the generator.

Claims 2 to 15 describe advantageous embodiments of the invention.

Other features, objects and advantages of the present invention will appear on reading the detailed description which follows and with reference to the appended drawings given by way of non-limiting examples and in which: FIG. 1 is a diagrammatic representation of a longitudinal section of an axial flow synchronous motor or generator according to the state of the art,

FIG. 2 is a schematic representation of a longitudinal section of an axial flow synchronous motor or generator according to a first embodiment of the present invention, this motor or generator combining axial flow with radial flux with the series of magnets. for the creation of the radial flow disposed at the periphery of the rotor,

FIG. 3 is a schematic representation of a longitudinal section of an axial flow synchronous motor or generator according to a first embodiment of the present invention, this motor or generator combining axial flow with radial flux with the series of magnets. for the creation of the radial flow disposed between the periphery and the drive axis of the rotor.

The figures are given by way of examples and are not limiting 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 particular the dimensions of the different parts of the engine or the generator are not representative of reality.

Figure 1 has already been described in the introductory part of the present application.

Referring to FIGS. 2 and 3, in general terms, an axial flux synchronous synchronous motor or generator 1 comprises a rotor 2 in the form of a disk integral with a median drive shaft 3, at least one stator 4, an air gap being defined between the rotor 2 and at least one stator 4, more precisely between a series of windings carried by the stator 4 and a series of permanent magnets carried by the rotor 2.

Thus, at least one series of permanent magnets 5 is carried by the rotor 2 and at least one series of associated coils 6 is carried by each stator 4. Said at least one series of magnets 5 and a series of coils 6 are positioned to create an axial magnetic flux with respect to the motor 1 or the generator, therefore substantially parallel to the drive axis 3. According to the invention, the rotor 2 comprises at least one auxiliary series of permanent magnets 7 cooperating with at least one auxiliary series of coils 8 carried by said at least one stator 4 or a portion secured to said at least one stator 4, the flow auxiliary magnet created in operation by said at least one auxiliary series of magnets 7 and at least one series of coils 8 being a radial magnetic flux with respect to the engine 1 or the generator.

Thus, it is possible to combine an axial flow with a radial flow which increases the torque developed by the engine 1 or the generator.

The stator 4 may be unique in one part or comprise several fixed parts relative to each other. Said at least one stator 4 can remotely surround the rotor 2 and comprise at least one series of coils 6 on each side of the rotor 2 in order to create an axial magnetic flux between air gaps with respect to the engine 1 or the generator. In this case, there are two air gaps between the rotor 2 and the stator 4 or each part of the stator 4.

In the embodiment of the invention shown in FIGS. 2 and 3, the rotor 2 comprises an excess thickness 9, 9a carrying said at least one auxiliary series of magnets 7 extending at least partially in the length of the excess thickness 9, 9a. Said at least one stator 4 then carries at least the auxiliary series of coils 8 vis-à-vis the outer face of the extra thickness 9, 9a. There is thus created a third air gap between the auxiliary series of coils 8 and the auxiliary series of magnets 7 at the periphery of the rotor 2, in order to create a first radial magnetic flux with respect to the engine 1 or the generator.

In Figure 2, the extra thickness 9 is on the outer periphery of the rotor 2 while in Figure 3, which the rotor 2 comprises an extra thickness 9a between said at least one series of permanent magnets 5 and the axis 3 of median training.

Preferably, but not limited to, the extra thickness 9, 9a can be removably attached to the rotor being movable radially relative to the engine 1. This allows a specific adaptation of the engine 1 to its function as previously indicated. It can be the same for the series of coils 8 which can be mobile or there can be two or more series of windings of which only the series or the series being close to the excess thickness 9, 9a is or are fed.

In Figure 2, the auxiliary series of coils 8 is disposed laterally to and outside the rotor. The stator 4, consisting of several parts or not, virtually surrounds the entire rotor 2.

In FIG. 3, the auxiliary series of coils 8 may be arranged laterally either closer to or further from the drive shaft 3 than the auxiliary series of magnets 7. In FIG. 3, it is this first position. which is shown.

In FIGS. 2 and 3, the excess thickness 9, 9a advantageously extends perpendicularly to the plane of the rotor disk 2 on both sides of the rotor 2. Its length is calculated as a function of the electrical current flowing through the auxiliary series of windings 8 on the stator 4 and the magnetization force of the auxiliary series of magnets 7 that it carries.

It should be noted that the series of magnets and winding mentioned above may contain from one to several magnets or winding. For the embodiments of the present invention shown in Figures 2 and 3, the series of magnets 5 may comprise two sets of magnets extending parallel in the length of the rotor 2.

In a general manner, according to a characteristic of the present invention, said at least one series of magnets 5 may consist of a first sub-series of magnets cooperating with the series of coils 6 on one side of the rotor 2 and a second sub-series of magnets cooperating with the series of coils 6 on the other side of the rotor 2.

The magnets of the series of magnets 5 and the auxiliary series 7 can be mounted with their polarity reversed.

According to another arrangement, the magnets of the series of magnets 5 and the auxiliary series of magnets 7 can be mounted according to a Halbach structure.

This makes it possible to establish, for the auxiliary series 7 of magnets, an increased magnetic field on the side turned respectively towards the auxiliary series of coils 8, while the magnetic field is decreased or canceled on the other side and for the series of coils. magnets 5 to provide two sub-series each with a magnetic field facing a respective series of coils 6. For all embodiments of the present invention, the rotor 2 may not have iron. The permanent magnets of the series of magnets 5 and the magnets of the auxiliary series of magnets 7 can be chosen from ferrite magnets, rare-earth magnets such as neodymium-iron-boron magnets or samarium cobalt magnets, magnets based on aluminum, nickel or cobalt, with or without thermoplastic binder.

In one embodiment of the invention, the magnets of the series of magnets 5 and the magnets of the auxiliary series of magnets 7 may be encapsulated in a thermosetting resin in the rotor 2.

In another embodiment of the invention, the rotor 2 may be in the form of a disk containing no iron and have housings respectively receiving a permanent magnet of one of the sets of magnets 5, 7 that it door. The permanent magnets are advantageously glued in their housing, for example at their four corners when they are square or rectangular. The permanent magnet associated with a housing has a thickness substantially greater than or equal to that of the housing.

The fact that the permanent magnets are respectively associated with such housings makes it possible to guarantee the cohesion between the magnets and the rotor 2, in particular when the rotor 2 rotates at a high rotational speed, which can cause the magnets to detach by centrifugal force. .

The fact of not including iron can also be applied for the stator 4 in one piece or in several parts. Said at least one series of coils 6 and, if appropriate, said at least one auxiliary series of coils 8 may advantageously have support means for the coils, said means not comprising iron. For example, the winding support means may be of plastic material, composite, ceramic or glass. These support means are advantageously in the form of teeth or notches.

Advantageously, also for all the embodiments of the invention, in the motor 1 or the electromagnetic generator according to the present invention, the winding or windings of the winding series 6, 8 may be covered with a protective hoop at least on one or sides turned respectively to the series of magnets 5, 7 permanent. This protective hoop can advantageously be formed by a ribbon heat-shrinkable, for example a layup of composite material based on glass fibers, this without this being limiting.

A conventional winding may consist of a good conductor wire wound on the support means advantageously flexible and elastically deformable. The series of coils 6, 8 can also be embedded in any insulating binder, for example a resin, to ensure good electromagnetic insulation thereof.

A non-limiting embodiment of a winding or windings for an engine or a generator may comprise one or more windings in the form of a rigid branch, for example three rigid branches, which corresponds to the use of a three-phase current. This or these rigid branches are advantageously in one piece.

The or each of these rigid branches may be formed of slots, each slot comprising a vertex framed by at least one lateral segment at each of its ends and a base connecting the slot to an adjacent slot of the rigid branch, each lateral segment connecting a end portion of the apex at an end portion of the base. It can be provided several rigid branches entangled in each other.

A preferred application of the embodiments described below is for a so-called flat motor or generator. Such an engine must make it possible to deliver the highest possible torque while having a very small footprint. The possibility of combining an axial flow with a radial flow and in particular an axial poly-airstream flow with a radial polyenfelt flow gives such a motor or generator a high potential.

However it is also possible that the engine comprises several concentric rotors with at least one rotor combining an axial flow with a radial flow.

Advantageously, the motor or the electromagnetic generator according to the present invention can be polyphase. In this case, it advantageously has at least one winding per phase of current.

The invention is in no way limited to the described and illustrated embodiments which have been given by way of example only.

Claims

Motor (1) or electromagnetic generator comprising a rotor

(2) in the form of a disk attached to an axis

(3) median drive, at least one stator (4), an air gap being defined between the rotor (2) and said at least one stator (4), at least one series of permanent magnets (5) being carried by the rotor (2) and at least one associated series of windings (6) being carried by said at least one stator (4), said at least one series of magnets (5) and a series of windings (6) being positioned for create an axial magnetic flux relative to the motor (1) or the generator, the rotor (2) comprising at least one auxiliary series of permanent magnets (7) cooperating with at least one respective auxiliary series of windings (8) carried by said at least one stator (4) or an integral portion of said at least one stator (4), the auxiliary magnetic flux created in operation by the auxiliary series of magnets (7) and windings (8) being a radial magnetic flux by relative to the motor (1) or the generator, characterized in that the rotor (2) comprises an extra thickness (9, 9a) carrying said at least one auxiliary series of magnets (7) extending along the length of the extra thickness (9, 9a), said at least one stator (4) carrying at least the auxiliary series of windings (8) facing a longitudinal face of the extra thickness (9, 9a), in order to create the magnetic flux radial relative to the motor (1) or the generator.

Motor (1) or generator according to the preceding claim, in which said at least one stator (4) surrounds at least partially at a distance the rotor (2) and comprises said at least one series of windings (6) on each side of the rotor ( 2) in order to create an axial magnetic flux which is poly air gaps relative to the motor (1) or the generator.

Motor (1) or generator according to the preceding claim, in which said at least one series of magnets (5) consists of a first sub-series of magnets cooperating with the series of windings (6) on one side of the rotor (2) and a second sub-series of magnets cooperating with the series of windings (6) on the other side of the rotor (2).

4. Motor (1) or generator according to any one of the preceding claims, in which the extra thickness (9, 9a) is removably fixed on the rotor and can be moved radially relative to the motor (1).

5. Motor (1) or generator according to any one of the preceding claims, wherein the rotor (2) comprises an extra thickness (9) at its external periphery.

6. Motor (1) or generator according to any one of the preceding claims, in which the rotor (2) comprises an extra thickness (9a) between said at least one series of permanent magnets (5) and the axis (3) middle drive.

7. Motor (1) or generator according to any one of the preceding claims, wherein the extra thickness (9, 9a) extends perpendicular to the plane of the disc forming the rotor (2).

8. Motor (1) or generator according to the preceding claim, in which the magnets of said at least one series (5) and of said at least one auxiliary series of magnets (7) are mounted according to a Halbach structure, establishing a magnetic field increased on the side turned respectively towards said at least one series of windings (6) associated for the series of magnets (5) and the auxiliary series of windings (8) for the auxiliary series of magnets (7) while the magnetic field is diminished or canceled on the other side.

9. Motor (1) or generator according to any one of the preceding claims, wherein the rotor (2) does not contain iron.

10. Motor (1) or electromagnetic generator according to the preceding claim, for which the permanent magnets of said at least one series of magnets (5) and the magnets of said at least one auxiliary series of magnets (7) 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 or cobalt, with or without a thermoplastic binder.

11. Motor (1) or generator according to any one of the two preceding claims, wherein the magnets of said at least one series of magnets (5) and the magnets of said at least one auxiliary series of magnets (7) are encapsulated in a thermosetting resin in the rotor (2).

12. Motor (1) or generator according to any one of the preceding claims, wherein said at least one series of windings (6) and said at least one auxiliary series of windings (8) have support means for the windings not containing no iron.

13. Motor (1) or generator according to the preceding claim, wherein the means for supporting the windings are made of plastic, composite, ceramic or glass.

14. Motor (1) or generator according to any one of the two preceding claims, wherein the support means are in the form of teeth or notches.

15. Motor (1) or generator according to any one of the preceding claims, which is a flat motor or generator.