Rotary electric machine

Abstract

The purpose of the present invention is to provide a rotary electric machine capable of suppressing discharge in a high-altitude environment. High output density of the rotary electric machine and reliability under low atmospheric pressure are ensured.　A rotary electric machine according to the present invention includes a coil and a stator core, the rotary electric machine being characterized by comprising, as an insulation structure between the coil and the stator coil, element wire insulation that is applied to the coil, insulation paper that is disposed between the element wire insulation and the stator core, and a semiconductive layer or a conductive layer that is disposed on at least part of the obverse and reverse surfaces of the insulation paper. A semiconductive layer is provided to the obverse surface of an insulation layer, the element wire insulation is rolled in using the insulation paper, and the insulation paper and the surface of the element wire insulation are electrically connected.

Description

Rotating electric machines

[0001] The present invention relates to a rotating electric machine.

[0002] For transportation equipment such as construction machinery, aircraft, trains, automobiles, buses, and trucks used in high-altitude environments, the power source is shifting from engines to electric vehicles. This requires equipment that can be used in any climate around the world, and in the case of aircraft, environmental resistance that can withstand sudden changes in altitude. At the same time, technological improvements are being required to improve cooling performance, increase voltage, and reduce weight.

[0003] A common issue with mobility at high altitudes is the significant deterioration of spatial and creepage insulation characteristics under low atmospheric pressure. In particular, insulation reliability in spatial gaps is a concern. Patent Documents 1 and 2 disclose a rotating electrical machine whose insulation system is composed of wire insulation, main insulation, and insulating paper (slot liner), and the insulation paper is provided with a semiconductive layer on the surface of the insulating paper to suppress discharge at the coil end.

[0004] JP 2019-75873 A JP 2005-229747 A

[0005] However, Patent Documents 1 and 2 do not address insulation systems that are composed of wire insulation and insulating paper, and a configuration that is specialized for suppressing partial discharge in such a configuration is required.

[0006] The technical challenges in achieving both electrification and miniaturization for rotating electrical machines used in high-altitude environments are as follows: The first is to reduce the thickness of the insulation through structural limit design aimed at the partial discharge inception voltage, taking into account long-term degradation; the second is to deal with defects such as peeling caused by vibration and thermal degradation that occur during long-term operation; and the third is to deal with variations in clearance, which are difficult to manage in design and manufacturing.

[0007] An object of the present invention is to provide a rotating electric machine capable of suppressing discharge in a high-altitude environment.

[0008] The rotating electric machine of the present invention is characterized in that, in a rotating electric machine having a coil and a stator core, the insulation configuration between the coil and the stator core comprises wire insulation applied to the coil, insulating paper arranged between the wire insulation and the stator core, and a semiconductive or conductive layer arranged on at least a portion of the front and back surfaces of the insulating paper.

[0009] According to the present invention, it is possible to provide a rotating electric machine that can suppress discharge in a high-altitude environment.

[0010] 1 is a cross-sectional view of a slot portion of a rotating electric machine according to the present embodiment. 2 is an external view of a rotating electric machine according to the first embodiment. 3 is an external view of a rotating electric machine according to the first embodiment. 4 is an external view of a rotating electric machine according to the first embodiment. 5 is an external view of a rotating electric machine according to the first embodiment. 6 is an external view of a rotating electric machine according to the first embodiment. 7 is an external view of a rotating electric machine according to the first embodiment. 8 is an external view of a rotating electric machine according to the first embodiment. 9 is an external view of a rotating electric machine according to the first embodiment.

[0011] In an embodiment of the present invention, the insulation thickness and air insulation distance are set so that the minimum value of the discharge curve, taking into account the potential distribution of the insulation, is higher than the applied voltage. Furthermore, the rotating electric machine does not require main insulation, and the insulation system is based on only two components: wire insulation and the back surface of the insulating paper, thereby improving heat dissipation. A semiconductive layer is then provided on the surface of the insulating layer, and the wire insulation is wrapped in insulating paper, electrically connecting the insulating paper and the surface of the wire insulation, eliminating the potential difference and suppressing and preventing discharge. The surface of the liner on the stator core side is also made of a semiconductive layer, eliminating the potential difference even if peeling or gap variations occur.

[0012] The configuration of a rotating electric machine according to the present invention will be described in the following examples. The following examples ensure high power density and reliability of the rotating electric machine under low atmospheric pressure. Note that the same reference numerals in all subsequent figures indicate the same components. Combinations of the examples shown below in this patent are also included as embodiments.

[0013] 1 shows a cross-sectional view of a typical slot portion of a rotating electrical machine. The slot portion of a rotating electrical machine basically includes a coil 1, wire insulation 2, insulating paper 3, and a stator core 9.

[0014] The coil 1 can be either square or round wire. It can also be single or bundled Litz wire. The surface of the coil 1 is covered with wire insulation 2, which can be enamel coating, Kapton coating, mica-wrapped insulation, glass insulation, permeable insulation film, or fluorine film, but any insulating material can be used. From the perspective of heat dissipation, this paper targets an insulation system that does not have a main insulation, as in previous documents.

[0015] The insulating paper 3 is also called a slot liner and is generally made of aramid or the like as a base material. However, it also includes a bobbin wound around the coil 1, and there are no particular restrictions on the material.

[0016] 2 shows an external view of the rotating electric machine of the first embodiment. The rotating electric machine includes a coil 1, wire insulation 2, insulating paper 3, and a stator core 9. Semiconductive layers 5 are provided on both sides of the insulating paper 3 and on the surface of the wire insulation 2. For clarity, an enlarged view of the insulating paper 3 and the semiconductive layer 5 is shown.

[0017] In this example, the insulating paper 3 is B-shaped, as indicated by the bold solid line in the drawing. The insulating paper 3 is wound around the wire insulation 2. Two coils 1 are placed in the blank areas of the B shape.

[0018] In each figure, the case of two coils will be explained. The upper side of coil 1 is called the N-plane, the left side is called the W-plane, the lower side is called the S-plane, and the right side is called the E-plane. In the drawings, the upper side of the upper coil 1 is called the N1-plane, the left side is called the W1-plane, the lower side is called the S1-plane, and the right side is called the E1-plane. The upper side of the lower coil 1 is called the N2-plane, the left side is called the W2-plane, the lower side is called the S2-plane, and the right side is called the E2-plane.

[0019] The B-shaped insulating paper 3 in Figure 2 is wrapped around the W1, N1, E1, and S1 surfaces. It is also wrapped around the W2, S2, E2, and N2 surfaces. The S1 and N2 surfaces are spaced apart at a predetermined distance, and the W1 and W2 surfaces, and the S1 and N2 surfaces are not connected and are spaced apart at a predetermined distance. In other words, the B-shaped insulating paper 3 is arranged so as to surround the upper coil 1, with a gap at the left end of the center, and is arranged so as to surround the lower coil 1, with a gap at the left end of the center.

[0020] The semiconductive layer 5 is indicated by a dotted line in the drawing. Examples of materials for the semiconductive layer 5 include carbon, silicon carbide, semiconductive glass, silicon nitride, silane, and compounds thereof. It is desirable to use at least one of these. However, there is no limitation on the material as long as it exhibits semiconductivity.

[0021] The semiconductive layer 5 is provided on the coil side of the insulating paper 3. In addition, the semiconductive layer 5 is provided on the outside (opposite the coil side) so as to surround the B-shaped insulating paper 3.

[0022] In this way, by providing the semiconductive layer 5 on the surface of the insulating paper 3, part of the semiconductive layer 5 on the surface of the insulating paper partially contacts the stator core 9, thereby establishing electrical continuity. This causes the semiconductive layer 5 on the surface of the insulating paper and the stator core 9 to have the same potential, and no potential difference occurs in the gap or clearance between the insulating paper 3 and the stator core 9. This makes it possible to suppress and prevent discharge in the gap or clearance.

[0023] As described above, in a rotating electric machine having a coil 1 and a stator core 9, the insulation configuration between the coil 1 and the stator core 9 includes wire insulation 2 applied to the coil 1, insulating paper 3 arranged between the coil 1 and the stator core 9, and semiconducting layers 5 arranged on at least a portion of the front and back surfaces of the insulating paper 3. With this configuration, this embodiment can suppress and prevent discharge under low atmospheric pressure in a high-altitude environment. This also ensures insulation properties equal to or better than those on the ground, making it possible to increase the system voltage.

[0024] Specifically, it is possible to suppress and prevent discharge in gaps and clearances, which are weak points under low atmospheric pressure.

[0025] It is also possible to use a conductive layer instead of the semiconductive layer 5. In this case, it is necessary to take care to prevent the conductive layer from peeling off or being chipped and becoming mixed into the motor as foreign matter.

[0026] Furthermore, a semiconductive or conductive layer may be provided on the surface of the wire insulation 2. This is the portion indicated by the dashed line in the drawing. This arrangement also provides a predetermined effect.

[0027] 3 shows an external view of a rotating electrical machine according to the present embodiment 2. In contrast to the embodiment 1, the region where the semiconductive layer 5 is provided is limited.

[0028] The creepage distance is determined by the applied voltage of the target rotating electrical machine, but the creepage distance is achieved by providing a non-semiconductive portion in the center where the B-shaped insulating paper 3 is woven. In the portion where the B-shaped insulating paper 3 is woven, the semiconductive layer 5 on the front side of the insulating paper 3 does not come into contact with the semiconductive layer on the back side.

[0029] As described above, the insulating paper 3 is B-shaped, has two coils, and is wound around the wire insulation 2 in a structure in which both ends of the insulating paper 3 are woven between the two coils 1, and the woven surface of the insulating paper 3 does not have the semiconductive layer 5. This prevents the semiconductive layer 5 on the front surface of the insulating paper 3 from coming into contact with the semiconductive layer on the back surface.

[0030] 4 shows an external view of a rotating electric machine according to the third embodiment. In this embodiment, both surfaces of the insulating paper 3 are formed with semiconductive layers 5, and the surface of the coil 1 is formed with wire insulation 2. An insulating layer 8 is provided in the area where the W1 and W2 surfaces are not connected to the S1 and N2 surfaces and are spaced apart by a predetermined distance. In other words, by providing the insulating layer 8 at the end of the B-shaped insulating paper, insulation between the inner and outer semiconductive layers 5 is ensured.

[0031] The edge of the B-shaped insulating paper refers to the gap at the left edge of the center of the B-shape described above. By providing the insulating layer 8 at the edge of the insulating paper 3, the insulator is prevented from being exposed on the surface of the insulating paper in the area where the back and front surfaces meet, preventing the insulating paper from becoming semi-conductive or conductive.

[0032] 5 shows an external view of a rotating electrical machine according to the fourth embodiment. In this embodiment, the surface of the insulating paper 3 facing the stator core 9 is a semiconductive layer 5, and the surface of the coil 1 is wire insulation 2.

[0033] In this case, there is no semiconductive layer 5 on the coil 1 side of the wire insulation 2 and insulating paper 3, and potential occurs in the gap. Discharge can be suppressed and prevented by filling this gap with an insulating material using vacuum impregnation or the like.

[0034] FIG. 6 shows an external view of a rotating electric machine according to the fifth embodiment. This embodiment has a structure in which a plurality of coils 1 are wound together with insulating paper 3. The insulating paper 3 in FIG. 6 is wound together on the N1 surface (coil side), E1 surface, E2 surface, S2 surface, W2 surface, and W1 surface, and the N1 surface connected to the W1 surface is arranged at a predetermined distance from the N1 surface (coil side) on the opposite side of the coil. The N1 surface (coil side) is arranged at a predetermined distance from the W1 surface.

[0035] A semiconductive layer 5 is provided on both the coil side and the opposite side of the insulating paper 3. This type is characterized by superior manufacturability and heat dissipation compared to the B-type. However, when potential sharing occurs between coils due to surges or the like, the B-type insulating paper 3 provides better insulation.

[0036] FIG. 7 shows an external view of a rotating electrical machine according to the sixth embodiment. In contrast to the fifth embodiment, this embodiment has an insulating layer 8 between the coils (S1 surface and N2 surface). The insulating layer 8 is connected to the W surface and the E surface. Semiconducting layers 5 are provided on both the coil side and the opposite side of the insulating paper 3. This configuration is effective when potential sharing occurs between the coils 1 due to a surge or the like.

[0037] FIG. 8 shows an external view of a rotating electric machine according to the seventh embodiment. In this embodiment, the insulating paper has an S-shaped structure. The S-shape of the insulating paper 3 is wound on the S1, E1, N1, W1, N2, E2, S2, and W2 surfaces. The S1 surface is not in contact with the W1 surface and is spaced a predetermined distance apart. The W2 surface is not connected to the W1 and N2 surfaces and is spaced a predetermined distance apart. In this S-shape, the front and back of the insulating paper 3 are interchanged between the upper and lower coils, so the structure must ensure that the surface of the wire insulation 2 does not have the same potential as the stator core 9.

[0038] For example, the range of the semiconductive layer 5 is as shown in the figure, but the above requirement can be met by not providing the semiconductive layer 5 only in the central region of the insulating paper 3, or by removing the band.

[0039] This embodiment is not limited to this shape, and includes any structure in which the surface of the wire insulation does not have the same potential as the stator core 9.

[0040] Next, an application example of the rotating electric machine according to this embodiment will be described. Fig. 9 shows a crane 800 for construction machinery, which is an example of construction machinery. A motor 801, which is a rotating electric machine, and an inverter 802, which is a power converter, are stored and arranged in an electric machine room below a tower 805, next to a control room 804. In other words, the motor 801 is arranged at the base of the legs of the crane 800. However, there are no limitations on the arrangement.

[0041] As described above, by applying the rotating electric machine of the embodiment to the crane 800, the drive system of the crane 800 can maximize the insulation performance and suppress and prevent insulation degradation even if peeling occurs due to long-term deterioration. In addition, it can suppress and prevent discharge caused by gap variations due to manufacturing errors.

[0042] 10 shows an example of an electric aircraft 600. A drive system 603 can be located at a location on a wing 604. However, unlike a jet engine, in this example, multiple drive systems 603 can be located.

[0043] This is because, compared to conventional jet engines, when the rotating electric machine of this embodiment is applied, the drive system 603 consisting of the motor 601 and inverter 602 is small and lightweight, which increases the degree of freedom in the arrangement on the aircraft. Also, when the rotating electric machine of this embodiment is applied, it is possible to suppress and prevent discharge under low pressure in a high-altitude environment. It is possible to ensure insulation properties equal to or better than those on the ground, and to increase the system voltage.

[0044] 1...coil, 2...wire insulation, 3...insulating paper, 5...semiconductive layer, 8...insulating layer, 9...stator core, 600...electric aircraft, 601...motor, 602...inverter, 603...drive system, 604...wing, 800...crane, 801...motor, 802...inverter, 804...cockpit, 805...tower

Claims

1. A rotating electric machine having a coil and a stator core, characterized in that the insulating structure between the coil and the stator core comprises wire insulation applied to the coil, insulating paper placed between the wire insulation and the stator core, and a semiconductive or conductive layer placed on at least a portion of the front and back surfaces of the insulating paper.

2. A rotating electric machine as claimed in claim 1, characterized in that the insulating paper is B-shaped, there are two coils, and the insulating paper wound around the wire insulation is structured so that both ends of the insulating paper are woven between the two coils, and the woven surface of the insulating paper does not have the semiconductive layer.

3. A rotating electric machine as claimed in claim 1, wherein a creepage distance is ensured between the semiconductive layers on the back and front of the insulating paper in the area where the back and front surfaces meet, so that the insulator is not exposed on the surface of the insulating paper and becomes semiconductive or conductive.

4. A rotating electric machine as claimed in claim 1, characterized in that an insulating layer is provided at the end of the insulating paper in the area where the back surface and front surface meet, so that the insulator is not exposed on the surface of the insulating paper and becomes semi-conductive or conductive.

5. A rotating electric machine according to claim 1, characterized in that the semiconductive layer or the conductive layer is disposed on the surface of the wire insulation.

6. A rotating electric machine according to claim 1, wherein a plurality of said coils are wound together with said insulating paper.

7. A rotating electric machine according to claim 6, wherein an insulating layer is provided between the plurality of coils.

8. A rotating electric machine according to claim 1, wherein the insulating paper has an S-shape.

9. A rotating electric machine according to claim 1, characterized in that the semiconductive layer is made of at least one of carbon, silicon carbide, semiconductive glass, silicon nitride, silane and compounds thereof.

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