Electric machine

Abstract

The invention relates to an electric machine comprising at least one winding, which in turn comprises at least one cable, wherein the at least one cable consists of a structure comprising a plurality of carbon nanotubes (1) aligned in a substantially parallel manner, wherein the structure of the at least one cable comprises at least one first doping agent (2) disposed in spaces (3) between the carbon nanotubes (1), wherein the at least one first doping agent (2) is a material that transfers charge to the carbon nanotubes and increases the electrical conductivity thereof.

Description

[0001] Electric machine

[0002] DESCRIPTION

[0003] Object of the invention

[0004] The present invention relates to an electrical machine, particularly an electric motor or an electric generator, comprising at least one winding or coil made of at least one lightweight conductive wire or cable, manufactured from a conductive material with a weight much lower than that of copper or other materials conventionally used in the manufacture of electric motors.

[0005] The electric machine, the subject of the present invention, achieves high efficiency with minimal heat losses due to the high conductivity of the material used in at least one of its windings, while simultaneously achieving a significant weight reduction compared to other conventional electric machines of the same nominal power. These characteristics make the electric machine, the subject of the present invention, a device particularly suitable for applications where weight plays a crucial role, such as aeronautical applications.

[0006] The electric machine, the subject of the present invention, has application in the industry dedicated to the design, manufacture, marketing and operation of electric machines, particularly electric motors and, more specifically, electric motors for aeronautical applications.

[0007] Background of the invention and technical problem to be solved

[0008] In the state of the art, the need of the aeronautical industry to develop, design and build aircraft with increasingly lower weight is well known, in order to achieve a reduction in fuel consumption, with the consequent benefit in economic and environmental terms.

[0009] To achieve this reduction in aircraft weight, new structural materials are continuously researched and developed that allow their use in various parts of the aircraft, achieving a reduction in weight without compromising their resistance qualities to the stresses to which they will be subjected during the aircraft's useful life.

[0010] Aircraft incorporate a multitude of electronic and electrical systems, including electric motors that perform a wide variety of functions (deployment / retraction of ailerons, landing gear, fluid propulsion, etc.).

[0011] With a view to achieving a reduced weight electric motor, research has been conducted on electric motors that incorporate windings made from carbon nanotube (CNT) fibers.

[0012] The document “On the feasibility of carbon nanotube windings for electrical machines — Case study for a coreless axial flux motor” (Vandana Rallabandi; Narges Taran; Dan M. Ionel; John F. Eastham. 2016 IEEE Energy Conversion Congress and Exposition (ECCE)) describes studies on the use of carbon nanotubes (CNTs) for the construction of electric motor windings.

[0013] However, despite the studies carried out and published in the previous document, to date no electric motor has been achieved that, in addition to achieving a significant weight reduction, can achieve performance equal to or better than that of conventional electric motors with copper wire or cable windings. Description of the invention

[0014] In order to solve the aforementioned problems, the present invention relates to an electric machine, which allows for high performance and, at the same time, a reduction in weight compared to other conventional electric machines of the same nominal power.

[0015] The electrical machine, the subject of the present invention, comprises at least one winding or coil which in turn comprises at least one cable.

[0016] The at least one cable is made of a structure comprising a plurality of substantially parallel carbon nanotubes (CNTs).

[0017] Novelly, in the electrical machine that is the subject of the present invention, the structure of said at least one cable comprises at least one first doping agent disposed in the interstices existing between the carbon nanotubes, wherein the at least one first doping agent is a material that transfers charge to the carbon nanotubes and increases their electrical conductivity.

[0018] By using the cable structure of at least one winding, as defined above, an electrical machine is achieved with very low heating losses and a very low weight compared to other electrical machines of the same nominal power.

[0019] Preferably, at least one first doping agent (or intercalated material) is aluminum trichloride (AlCl3).

[0020] Alternatively, according to another possible embodiment, at least one first doping agent can be bromine (Br). Carbon nanotubes (CNTs) can be single-walled (SWCNTs).

[0021] Alternatively, carbon nanotubes (CNTs) can be multi-walled (MWCNTs) and, more specifically, double-walled (DWCNTs).

[0022] Preferably, according to the present invention, the electrical machine is an electric motor. However, according to alternative embodiments, the electrical machine could be, for example, a generator or a transformer.

[0023] The present invention also relates to a method for manufacturing an electrical machine, as described above.

[0024] The procedure for manufacturing a machine comprises arranging a structure of carbon nanotubes (CNTs) aligned in a substantially parallel manner, exposed to an atmosphere saturated with vapor of the first doping agent.

[0025] Preferably, the arrangement of the carbon nanotube structure, immersed in a saturated vapor solution of the first doping agent, is carried out at a pressure close to vacuum, for example, a pressure of approximately 320 mbar.

[0026] Preferably, the procedure involves using aluminum trichloride (AlCl3) as the first doping agent.

[0027] When aluminum trichloride (AlCl3) is used as the first doping agent, the manufacturing process for an electric motor preferably comprises using a two-zone vapor transport technique for doping the carbon nanotube structure. This two-zone vapor transport technique comprises, first, placing the carbon nanotube structure and the first doping agent separately and then introducing them into a tubular capsule (e.g., a glass capsule) in an argon atmosphere inside a box. The capsule is then sealed under low vacuum (-320 mbar). The capsule is covered with a thermal blanket that creates a temperature gradient between the first doping (or intercalating) agent and the carbon nanotube structure. Vapor exposure is maintained for 24 h. Subsequently, the doped carbon nanotube structure is removed and placed in an argon atmosphere inside a box.

[0028] Alternatively, the procedure may involve using bromine (Br) as the first doping agent.

[0029] In the case of using bromine (Br) as the first doping agent, the manufacturing procedure of an electric machine preferably comprises using a vapor transport technique of a zone for doping the carbon nanotube structure.

[0030] This single-zone vapor transport technique comprises, first, placing the carbon nanotube structure in a tubular capsule (e.g., a glass capsule) and sealing the capsule under low vacuum (-320 mbar). The first dopant (intercalator) is introduced into the system, creating a saturated atmosphere. Vapor exposure is maintained for extended periods of 12 to 24 hours.

[0031] Brief description of the figures

[0032] The following figures have been included as part of the explanation of at least one embodiment of the invention. Figure 1: shows a simplified cross-sectional view of an internal cable structure, said structure being based on carbon nanotubes.

[0033] Figure 2: shows a view of the structure of Figure 1, where the interstices between the carbon nanotubes are filled by a doping agent.

[0034] Detailed description

[0035] The present invention relates, as previously mentioned, to an electric machine. More particularly, the present invention relates to an electric motor.

[0036] The electrical machine that is the subject of the present invention comprises a plurality of windings or coils, each of which comprises at least one wire.

[0037] The cable is made of a structure based on carbon nanotubes (1) (CNTs).

[0038] Figure 1 shows the internal structure of a cable, as shown in a simplified cross-sectional view. Carbon nanotubes (1), specifically double-walled carbon nanotubes (DWCNTs), are visible in Figure 1.

[0039] According to the present invention, the cable structure comprises at least one doping agent (2) that occupies the interstices (3) existing between the carbon nanotubes (1).

[0040] Figure 2 shows a simplified cross-sectional view of a cable, where the cable structure comprises the dopant (2) occupying the interstices (3) between the carbon nanotubes (1).

Claims

CLAIMS 1. An electrical machine comprising at least one winding which in turn comprises at least one wire, wherein the at least one wire is made of a structure comprising a plurality of carbon nanotubes (1) aligned in a substantially parallel manner, characterized in that the structure of the at least one wire comprises at least one first dopant (2) disposed in the interstices (3) existing between the carbon nanotubes (1), wherein the at least one first dopant (2) is a material that transfers charge to the carbon nanotubes and increases their electrical conductivity.

2. Electric machine according to claim 1, characterized in that at least one first doping agent (2) is aluminum trichloride (AlCl3).

3. Electric machine according to claim 1, characterized in that at least one first doping agent (2) is bromine (Br).

4. Electric machine according to any of the preceding claims, characterized in that the carbon nanotubes (1) are single-walled (SWCNT).

5. Electric machine according to any of claims 1 to 3, characterized in that the carbon nanotubes (1) are multi-walled (MWCNT).

6. Electric machine according to any of claim 5, characterized in that the carbon nanotubes (1) are double-walled (DWCNT).

7. An electric machine according to any of the preceding claims, characterized in that the electric machine is an electric motor.

8. A method for manufacturing an electric machine according to any of claims 1 to 7, characterized in that it comprises arranging a structure of carbon nanotubes (1) aligned in a substantially parallel manner, exposed to an atmosphere saturated with vapor of the first doping agent (2).

9. Method for manufacturing an electric machine according to claim 8, characterized in that the arrangement of the carbon nanotube structure (1), immersed in a saturated vapor solution of the first dopant (2), is carried out at a pressure of approximately 320 mbar.

10. Method for manufacturing an electrical machine according to claim 8 or 9, characterized in that the first doping agent (2) is aluminum trichloride (AlCl3).

11. Method for manufacturing an electric machine according to claim 10, characterized in that it comprises using a two-zone vapor transport technique for doping the carbon nanotube structure (1).

12. Method for manufacturing an electrical machine according to claim 8 or 9, characterized in that the first doping agent (2) is bromine (Br).

13. Method for manufacturing an electric machine according to claim 12, characterized in that it comprises using a one-zone vapor transport technique for doping the carbon nanotube structure (1).

Images