Superconducting motor and aircraft

Abstract

The invention relates to a superconducting motor and aircraft, the superconducting motor (100) comprising: a rotor (102) carrying permanent magnets (110) able to rotate about a longitudinal axis (X); a stator (103) passing through apertures (116) distributed around the rotor (102); and for each aperture, two coils (150) made of superconducting material and electrically powered so as to generate a magnetic field, wherein each coil (150) comprises a first straight section (152a) passing through said aperture (116), a second straight section (152b) passing through another aperture (116), and two curved sections (154a-154b), wherein the two curved sections each connect one end of the first straight section (152a) and one end of the second straight section (152b) to each other, wherein the straight sections (152a) of the two coils (150) passing through said aperture (116) are radially stacked. The particular arrangement of the coils makes it possible to limit losses.

Description

Technical Field

[0001] This invention relates to the general field of superconducting motors, and more particularly to superconducting motors comprising stacked coils, and aircraft comprising at least one such superconducting motor. Background Technology

[0002] like Figure 7 and Figure 8 The prior art superconducting motor, schematically illustrated, includes a rotor 602 having a rotor core 602a made of a ferromagnetic material such as all ferroalloys used in motors. The rotor core 602a is generally cylindrical and has a central bore in which the motor shaft is fitted and rigidly fixed. The motor shaft is coaxial with the axis of rotation of the rotor core 602a, which overlaps with the longitudinal axis of the superconducting motor.

[0003] The rotor 602 also includes permanent magnets 604 supported by a rotor core 602a. Multiple permanent magnets 604 are present at an angle and regularly distributed and spaced apart from each other at the periphery of the rotor core 602a. For simplicity, the permanent magnets... Figure 7 It is not shown in detail, but is represented by a single element.

[0004] The superconducting motor includes a stator 606 arranged around a rotor 602 and comprising a stator core 606a made of a ferromagnetic material such as all ferroalloys used in motors. The stator core 606a has an overall hollow cylindrical shape coaxial with the longitudinal axis. The stator core 606a includes pairs of apertures 606b extending parallel to the longitudinal axis.

[0005] The stator 606 includes a plurality of coils 610 supported by a stator core 606a and distributed at an angle and regularly spaced apart from each other on the inner periphery of the stator core 606a (facing a set of permanent magnets 604). The coils 610 are energized to generate a magnetic field, which drives the rotor 602 to rotate by means of the permanent magnets 604.

[0006] Each coil 610 is made of a superconducting material strip to form a loop therein, which, for two angled successive apertures 606b, has: a first straight section 610a passing through the first aperture 606b, a second straight section 610b passing through the second aperture 606b, and two curved sections 610c to 610d, wherein each of the two curved sections 610c to 610d connects one end of the first straight section 610a and one end of the second straight section 610b to each other.

[0007] Therefore, each orifice 606b is traversed by two straight sections 610a to 610b of two consecutive coils 610, and these two straight sections 610a to 610b are arranged side by side.

[0008] To limit the temperature rise, conduit 614 presses against one of the straight sections 610a to 610b and the curved section 610c of each coil 610, and the heat transfer fluid is conveyed through conduit 614. In this case, the unconnected end of conduit 614 allows fluid connection to a system for moving the heat transfer fluid, such as a pump and a tank for the heat transfer fluid.

[0009] During operation, each coil 610 is energized by alternating current to generate a magnetic field that interacts with the permanent magnet, thereby driving the rotor 602 and the motor shaft to rotate.

[0010] Figure 9 A graph representing the magnetic flux density at orifice 606b is shown. Figure 9 It is shown that a portion of coil 610 is placed in a region of higher density (where flux lines are closer together) due to the input of magnetic flux from coil 610 and the input of flux from the permanent magnet of the rotating part.

[0011] In such a superconducting motor, losses are related to the maximum current that can be injected into the coil before it becomes a resistor. The larger this maximum current, the lower the losses. This maximum current decreases with the current injected into the coil and the magnetic flux density applied to the coil. Therefore, to increase the power of the superconducting motor, it is desirable to reduce the applied magnetic flux density. With existing arrangements, some straight sections in the orifice experience high magnetic flux density due to the flux generated by the coil and the permanent magnet, leading to significant losses. Therefore, it is desirable to find an arrangement that improves this situation. Summary of the Invention

[0012] One object of the present invention is to provide a superconducting motor whose arrangement allows for the reduction of losses by modifying the position of the coils relative to the magnetic flux they experience.

[0013] For this purpose, a superconducting motor is provided, the superconducting motor comprising:

[0014] - A rotor having a rotor core that carries permanent magnets capable of rotating about a longitudinal axis.

[0015] - A stator, arranged outside the rotor and comprising a stator core, the stator core being pierced by orifices spaced at an angle and regularly distributed around the rotor, and

[0016] - For each orifice, two coils are provided. These coils are made of superconducting material and are intended to be energized to generate a magnetic field that drives a rotor to rotate by means of a permanent magnet. Each coil includes a first straight section passing through the orifice, a second straight section passing through the other orifice, and two curved sections, wherein each of the two curved sections connects one end of the first straight section and one end of the second straight section to each other. The straight sections of the two coils passing through the orifices are radially stacked. Each orifice includes a region with a high magnetic flux density and another region with a low magnetic flux density, wherein the stack is arranged in the other region.

[0017] The specific arrangement of the coils allows for the limitation of losses.

[0018] According to a particular embodiment, when the first straight section of the coil is located at the outer or inner layer of its stack, the second straight section of the same coil is also located at the outer or inner layer of its stack.

[0019] Advantageously, for two straight sections stacked in the orifice, the superconducting motor includes a conduit for conveying heat transfer fluid and arranged between the two straight sections.

[0020] According to a particular embodiment, when the first straight section of the coil is located at the outer layer of its stack, the second straight section of the same coil is located at the inner layer of its stack, and when the first straight section of the coil is located at the inner layer of its stack, the second straight section of the same coil is located at the outer layer of its stack.

[0021] Advantageously, for each coil, the superconducting motor includes a conduit at least partially adjacent to the outer side of the coil and for delivering heat transfer fluid.

[0022] Advantageously, for each coil, the superconducting motor includes a conduit that is at least partially adjacent to the inner side of the coil and delivers heat transfer fluid.

[0023] The present invention also provides an aircraft comprising at least one superconducting motor according to any of the embodiments presented above. Attached Figure Description

[0024] The features mentioned above, as well as other features of the invention, will become more apparent when reading the following description of at least one exemplary embodiment, which is given with reference to the accompanying drawings, in which:

[0025] Figure 1 A side view of the aircraft according to the present invention is shown.

[0026] Figure 2A cross-sectional view of a superconducting motor according to a first embodiment of the present invention is shown.

[0027] Figure 3 A perspective view of a portion of a superconducting motor according to a second embodiment of the present invention is shown.

[0028] Figure 4 A simplified axial view of a portion of a superconducting motor according to a first embodiment of the present invention is shown.

[0029] Figure 5 A simplified axial view of a portion of a superconducting motor according to a second embodiment of the present invention is shown.

[0030] Figure 6 A graph showing the magnetic flux distribution in the superconducting motor according to the present invention is shown.

[0031] Figure 7 A perspective view of a portion of a prior art superconducting motor is shown.

[0032] Figure 8 It shows Figure 7 A simplified axial view of a portion of a superconducting motor, and

[0033] Figure 9 A graph representing the magnetic flux distribution in a prior art superconducting motor is shown. Detailed Implementation

[0034] Figure 2 A superconducting motor 100 according to the present invention is schematically shown. The superconducting motor 100 is substantially similar to a prior art superconducting motor, but has a specific arrangement of coils. Figure 3 and Figure 5 A portion of the superconducting motor 100 according to the second embodiment is shown, and Figure 2 and Figure 4 A portion of a superconducting motor 100 according to a first embodiment is shown.

[0035] Therefore, the superconducting motor 100 includes a rotor 102 having a rotor core 104 carrying a permanent magnet 110. The rotor 102 is rotatable about a longitudinal axis X, and Figure 2 A cross-section of the superconducting motor 100 through a plane perpendicular to the longitudinal axis X is shown. Figure 4 and Figure 5 In the diagram, stator 103 is shown as a rectangle, but it should be understood that stator 103 is arc-shaped around the longitudinal axis X.

[0036] The rotor core 104 is made of a ferromagnetic material such as all ferroalloys used in electric motors. The rotor core 104 is cylindrical and coaxial with the longitudinal axis X, and has a central bore in which the motor shaft 108 of the superconducting motor 100 is fitted and rigidly fixed. The motor shaft 108 is coaxial with the longitudinal axis X.

[0037] Permanent magnets 110 are fixed to the rotor core 104 at its periphery. A plurality of permanent magnets 110 (six in this case) are present, angled and regularly distributed around the rotor core 104 and spaced apart from each other. Preferably, the permanent magnets 110 are radially magnetized relative to the longitudinal axis X in an alternating manner from one magnet to the next. For simplicity, in Figure 3 In the figure, the permanent magnet 110 is represented as a single element.

[0038] The superconducting motor 100 also includes a stator 103, which is arranged outside the rotor 102 and includes a stator core 114 made of a ferromagnetic material such as all iron alloys used in motors. The stator core 114 has a generally cylindrical shape that is coaxial with the longitudinal axis X.

[0039] The stator core 114 has an opening 116 on its cylindrical surface oriented toward the rotor 102, in which case the opening 116 is in the form of a slot open toward the rotor 102. According to an embodiment not shown, the opening 116 may be in the form of a tunnel through the stator core 114. The opening 116 extends parallel to the longitudinal axis X.

[0040] There are a plurality of orifices 116 (in this case, ten orifices 116) that are angled and regularly distributed around the rotor 102. Two adjacent orifices 116 are separated by teeth 118, which are integral with the stator core 114 and made of the same material as the stator core 114. In the case where the orifices 116 are in the form of tunnels, the orifices 116 are embedded in the stator core 114.

[0041] The stator 103 includes a specific arrangement of coils 150, in which the coils 150 are mounted between two adjacent openings 116 of the stator core 114.

[0042] Each coil 150 is made of a superconducting material and is constructed, for example, by means of a strip made of superconducting material wound itself into turns to form a generally planar surface. Each coil 150 is energized by a power supply to generate a magnetic field that drives the rotor 102 to rotate by means of a permanent magnet 110.

[0043] Therefore, as Figure 3As shown, for each orifice 116, the superconducting motor 100 includes two coils 150, 150', a portion of each of the two coils 150, 150' is located in the orifice 116 in question, and another portion of each of the two coils 150, 150' is located in the upstream orifice 116 and the downstream orifice 116 about the longitudinal axis X, respectively.

[0044] Each of the two coils 150, 150' includes: first straight sections 152a, 152b' passing through the aperture 116 in question parallel to the longitudinal axis X; second straight sections 152b, 152a' each passing through another aperture 116 parallel to the longitudinal axis X; and two curved sections 154a to 154b, 154a' to 154b' located outside the aperture 116. Each curved section 154a to 154b, 154a' to 154b' connects one end of the first straight section 152a, 152a' and one end of the second straight section 152b, 152b' to each other to form a loop.

[0045] According to the present invention, for two coils 150, 150' passing through the same aperture 116, the straight segments 152a, 152b' of each coil 150, 150' pass through the same aperture 116, and the straight segments 152a, 152b' of each coil 150, 150' are radially stacked, that is, the straight segments 152a, 152b' are arranged and stacked on the same radial plane P that passes approximately through the longitudinal axis X.

[0046] Therefore, in each aperture 116, the straight section 152a of the coil is stacked with the straight section of another coil present in the other aperture 116.

[0047] The stacking of straight segments 152a to 152b allows for the release of empty space in each orifice 116. Through this configuration, each orifice 116 includes a region with high magnetic flux density and another region with low magnetic flux density, with the stacked portion of straight segments 152a to 152b arranged in the other region. That is, the stacked portion of straight segments 152a to 152b is arranged in the region with the lowest magnetic flux density, thereby limiting losses. In each orifice 116, there exists a stacked portion of straight segments 152a to 152b and an empty space offset at an angle relative to the stacked portion.

[0048] Therefore, it is assumed here that the stacked portion is radial, and the inner portion of the stacked portion is oriented towards the longitudinal axis X, that is, towards the inside of the superconducting motor 100, while the outer portion of the stacked portion is oriented away from the longitudinal axis X, that is, towards the outside of the superconducting motor 100. Figures 3 to 6 As shown in the figure.

[0049] According to the first and second embodiments of the present invention, the stacking portion can take two different forms. Figure 2 and Figure 3 In the middle, the stacked part is located on the left side in the orifice 116, while... Figure 4 and Figure 5 In the middle, the stacked portion is alternatively located on the right side in the aperture 116. The positioning of the stacked portion in the aperture 116 can be modified based on the geometry of the superconducting motor 100 and the technical characteristics of the superconducting motor 100 resulting from its structure.

[0050] therefore, Figure 6 A graph representing the magnetic flux density at orifice 116 is shown. Figure 6 It is shown that no part of coil 150 is placed in the high-density area. Here, the high-density area is... Figure 6 The middle section is located on the left, and then the stacked section is arranged on the right so as not to be submerged in the high-density area.

[0051] With this arrangement, the coil 150 no longer experiences the same high magnetic flux as in the prior art, which allows for reduced losses. Furthermore, the space freed up in the orifice 116 allows for greater freedom in the support structure of the coil 150 and enables better thermal insulation.

[0052] Furthermore, since the performance of coil 150 depends on the orientation of the magnetic field, the choice between the first and second embodiments allows for the realization or even further restriction of the degree of freedom of loss.

[0053] In particular Figure 4 In the first embodiment of the invention shown, and considering the central aperture 116, each coil 150 is arranged radially entirely at the same level, that is, entirely on the inner or outer layer. The inner layer is oriented towards the longitudinal axis X, and the outer layer is oriented outward. Both the inner and outer layers take the form of a cylindrical surface surrounding the longitudinal axis X.

[0054] Therefore, the first curved sections 154a to 154b connect the straight sections 152a to 152b of their respective stacked portions located in the inner layer together, and the second curved sections 154a to 154b connect the straight sections 152a to 152b of their respective stacked portions located in the outer layer together.

[0055] In this first embodiment, when the first straight section 152a of the coil 150 is correspondingly located on the outer layer of its stack in the aperture 116 under discussion ( Figure 4 (in the upper part) or inner layer ( Figure 4 When the second straight section 152b of the same coil 150 is located in the lower part of the coil 150, it is also located in the outer or inner layer of its stack in another adjacent aperture 116.

[0056] In particular Figure 5 In the second embodiment of the invention shown, and considering the central aperture 116, each coil 150 transitions from an inner layer to an outer layer. The inner layer is oriented towards the longitudinal axis X, and the outer layer is oriented outward. Both the inner and outer layers take the form of a cylindrical surface surrounding the longitudinal axis X.

[0057] Therefore, the first curved sections 154a to 154b connect the straight section 152a of the stacked portion located in the inner layer and the straight section 152b of the stacked portion located in the outer layer together, and the second curved sections 154a to 154b connect the straight section 152a of the stacked portion located in the outer layer and the straight section 152b of the stacked portion located in the inner layer together.

[0058] In this second embodiment, when the first straight section 152a of the coil 150 is located in the outer layer of the aperture 116 in question (in... Figure 5 When the second straight section 152b of the same coil 150 is located in the inner layer of another adjacent aperture 116 (in the upper part of the middle), Figure 5 In the lower part of the coil 150, and when the first straight section 152a of the coil 150 is located in the inner layer in the aperture 116 under discussion, the second straight section 152b of the same coil 150 is located in the outer layer in another adjacent aperture 116.

[0059] To limit the increase in temperature, the superconducting motor 100 includes a heat exchanger system. The heat exchanger system includes a conduit 170 that meanders along the coil 150 and delivers heat transfer fluid from a heat transfer fluid reservoir and driven by a pump.

[0060] exist Figure 4 In the first embodiment of the invention shown, for the two straight sections 152a stacked in the orifice 116, the conduit 170 for conveying heat transfer fluid is arranged between the two straight sections 152a. Therefore, the conduit 170 is located in the intermediate layer between the outer layer and the inner layer.

[0061] exist Figure 3 and Figure 5In the second embodiment of the invention shown, for each coil 150, the superconducting motor 100 includes a conduit 170 that is at least partially adjacent to the outer side of the coil 150.

[0062] Therefore, in orifice 116, for the first straight section 152a of coil 150 located in the inner layer of its stack, the associated conduit 170 is located in an intermediate layer between the first straight section 152a and the first straight section 152a of another coil 150 located in the outer layer of its stack. Still in orifice 116, for the first straight section 152a of another coil 150 located in the outer layer of its stack, the associated conduit 170 extends beyond the outer layer, that is, it is located in a layer even further outward than the outer layer. Thus, each conduit 170 transitions from an intermediate layer to an even further outward layer.

[0063] Each conduit 170 here forms an open loop in which a curved portion connects two straight portions, wherein the curved portion follows a curved section 154a of an associated coil 150, and wherein each straight portion follows straight sections 152a to 152b of an associated coil 150.

[0064] The opposite arrangement is also possible, in which the conduit 170 is at least partially adjacent to the inner side of the associated coil 150.

[0065] As in the prior art, the free end of the conduit 170 is fluidly connected to a system for moving the heat transfer fluid, which in particular includes a pump and a tank for the heat transfer fluid.

[0066] The rotor 102 and stator 103 are housed within a motor housing 180, which is closed at both ends by sides, at least one of which is pierced by a central aperture to allow the motor shaft 108 to pass through. The stator 103 is fixedly mounted inside the motor housing 180, while the rotor 102 and motor shaft 108 are mounted, for example by means of bearings, to be able to rotate freely within the motor housing 180.

[0067] Figure 1 An aircraft 50 is shown, which includes, for example, at least one superconducting motor 100 according to the invention for driving the rotation of a propeller 52.

Claims

1. A superconducting motor (100), comprising: The rotor (102) has a rotor core (104) that carries a permanent magnet (110) that is rotatable about a longitudinal axis (X); A stator (103) is arranged outside the rotor (102) and includes a stator core (114) through which orifices (116) are angled and regularly distributed around the rotor (102); as well as For each aperture (116), two coils (150) are provided, the coils (150) being made of superconducting material and intended to be energized to generate a magnetic field, which drives the rotor (102) to rotate by means of the permanent magnet (110). Each coil (150) includes a first straight section (152a) passing through the aperture (116), a second straight section (152b) passing through the other aperture (116), and two curved sections (154a-154b). The curved sections (154a-154b) respectively connect one end of the first straight section (152a) and one end of the second straight section (152b) to each other. The straight sections (152a) of the two coils (150) passing through the aperture (116) are radially stacked. Each aperture (116) includes a region with a high magnetic flux density and another region with a low magnetic flux density, and the stacked portion is arranged in the other region.

2. The superconducting motor (100) according to claim 1, wherein, When the first straight section (152a) of the coil (150) is located at the outer or inner layer of the stack of the first straight section (152a), the second straight section (152b) of the same coil (150) is also located at the outer or inner layer of the stack of the second straight section (152b).

3. The superconducting motor (100) according to claim 2, wherein, For the two straight sections (152a) stacked in the orifice (116), the superconducting motor (100) includes a conduit (170) for conveying heat transfer fluid and arranged between the two straight sections (152a).

4. The superconducting motor (100) according to claim 1, wherein, When the first straight section (152a) of the coil (150) is located at the outer layer of the stack of the first straight section (152a), the second straight section (152b) of the same coil (150) is located at the inner layer of the stack of the second straight section (152b), and when the first straight section (152a) of the coil (150) is located at the inner layer of the stack of the first straight section (152a), the second straight section (152b) of the same coil (150) is located at the outer layer of the stack of the second straight section (152b).

5. The superconducting motor (100) according to claim 4, wherein, For each coil (150), the superconducting motor (100) includes a conduit (170) that is at least partially adjacent to the outer side of the coil (150) and delivers heat transfer fluid.

6. The superconducting motor (100) according to claim 4, wherein, For each coil (150), the superconducting motor (100) includes a conduit (170) that is at least partially adjacent to the inner portion of the coil (150) and delivers heat transfer fluid.

7. An aircraft (50) comprising at least one superconducting motor (100) according to claim 1.

Images