WO2015198406A1 - Rotating electric machine stator and rotating electric machine - Google Patents

Abstract

A rotating electric machine stator is equipped with: a circular ring-shaped stator core (1) having a plurality of slots (2) in a circumferential direction, said slots penetrating from an upper surface to a lower surface; and a winding inserted and disposed into said slots and wound around said stator core, wherein said winding is formed of a thin-film conductor (3), and said thin-film conductor has a continuous portion between one end and the other end of said winding that are current taking-out portions, said continuous portion penetrating three times or more between the upper and lower surfaces of said stator core through said slots without being welded.

Description

Stator of rotating electric machine and rotating electric machine

The present invention relates to a stator of a rotating electrical machine and a rotating electrical machine.

Electric vehicles and hybrid vehicles are attracting attention from the viewpoint of CO2 reduction. As motors used in these vehicles, high output is required, and from the viewpoint of installation space and fuel efficiency improvement by weight reduction of vehicles, miniaturization and weight reduction are also demanded.

A conventional motor is mainly a synchronous motor, and a copper wire is wound in a coil shape as a stator armature, and a rotating magnetic field is generated by flowing a three-phase alternating current, and magnetic attraction with the rotor field element is generated. The driving force was generated by the force and the repulsive force. In order to miniaturize the motor, miniaturizing the stator armature portion is one of the essential items.

As a high-power, small and lightweight motor, there is a superconducting motor using a superconducting coil. Patent Document 1 discloses a rotor using a Y-based or Bi-based thin film superconducting wire, and FIG. 1 shows a rotor in which a metal substrate carrying a superconducting thin film is arranged in the same direction via an insulating adhesive. Is disclosed. Further, FIGS. 2A and 2B disclose that the insulating adhesive is filled on the long side of the thin film cross section to fix the winding pattern.

Unexamined-Japanese-Patent No. 1-2255451

In the armature winding of the stator, although the method of using segments is adopted because of the complexity of the winding, it was necessary to weld and connect many segments. Therefore, if a thin film superconducting wire is used for winding with a continuous wire as in the stator winding of Patent Document 1, torsional folding or the like is required. For example, in order to form the rotor structure of FIG. 1 with the winding pattern of FIG. 2 (b) described in Patent Document 1, the thin film line is formed at the coil end to match the direction of the surface on which the superconducting thin film is laminated. It is necessary to twist, and there is a problem that the winding is easily distorted.

The above problem is solved, for example, by the invention described in the claims.

According to the present invention, distortion of the winding can be reduced.

It is a stator structural drawing using a thin film superconducting wire. It is a wire structure and sectional drawing of a thin film superconducting wire. It is a stator unit figure. It is a top view of a stator core. It is a stator structural drawing using a thin film superconducting wire.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. The present invention is not limited to the embodiments described here, and appropriate combinations and improvements can be made without departing from the scope of the present invention.

FIG. 1 is a perspective view showing a part of a stator wound with a thin film conductor. A slot 2 penetrating from the upper surface to the lower surface of the cylindrical stator core 1 is provided, and a thin film conductor 3 described later is inserted into the slot 2. The thin film conductor 3 is continuous except at both ends which are current extraction portions (not shown). The thin film conductor 3 passes through the slot 2 penetrating the stator core 1 and goes around the stator core 1 substantially while reciprocating between the upper side and the lower side of the stator core 1. In the figure, two thin film conductors 3 traced by dotted lines and broken lines are used. Although the number of reciprocations of the thin film conductor 3 varies depending on the number of slots, according to the present embodiment, since one long elongated conductor is passed through the slots, the number of reciprocations is not particularly limited.

The wire structure is shown in FIG. As the conductive material 5, a normal conductive material such as Cu, or a superconducting material such as MgB 2, Y-based or Fe-based can be used. When the conductive material 5 can be formed into a thick foil, only the conductive material 5 may be used as the thin film conductor 3 without forming a film on the metal substrate 4. In the present embodiment, the case of forming the conductive material 5 on the metal substrate 4 will be described. As a film forming method, a known method such as sputtering can be used.

After the conductive material 5 is formed on the metal substrate 4, as shown in the top view of FIG. 2, the conductive film forming plate 8 is alternately cut from one end and the other end to form a single elongated conductor. Do. The cutting method can use known methods, such as a laser. In addition, before cutting, the protective film 6 or the insulating material 7 may be formed on the surface of the conductive material 5 on the conductive material 5. FIG. 2 shows a structure in which the conductive material 5 is formed on the metal substrate 4, the protective film 6 is formed on the upper surface of the conductive material 5, and is covered with the insulating material 7.

When the conductive material 5 is coated on the metal substrate 4 as shown in FIG. 2 to form the thin film conductor 3, the thin film conductor 3 is inserted into the slot 2 so that the surface of the conductive material 5 is always in the same direction. . This eliminates the need for twisting the thin film wire at the coil end. That is, since the stator winding can be formed without significantly twisting the thin film conductor 3, not only the winding is not easily distorted, but also peeling of the conductive material 5 on the metal substrate 4 can be reduced.

By the way, in the conventional segment conductor, a plurality of V-shaped conductors are penetrated through the stator core, and the end of the conductor is welded to the end of the other conductor. That is, the stator core is penetrated twice (one round trip) for one conductor, and the ends of all the conductors are welded to form a current path. Compared to this case, in the present embodiment, the stator core can be penetrated three or more times (1.5 reciprocations or more) with one thin film conductor, and the number of penetrations is not particularly limited. There is no need to connect multiple conductors between each other. Therefore, since it is not necessary to weld the conductors to be used, the manufacturing process can be simplified.

For example, when a thin film MgB 2 is used as the conductive material 5, it is preferable that the cross section be observed with an electron microscope and that there be no void in the MgB 2 layer. When there are holes, the flow path through which the current flows decreases. Any method can be used as long as the method does not create pores. For example, a vapor deposition method, a sputtering method, or the like can be used. Specific methods include PLD (laser ablation) method, electron beam method, ion beam method and the like.

When MgB 2 is used, the MgB 2 is deposited on the substrate and then covered with the protective film 6. The protective film 6 may be any as long as it blocks the contact between MgB 2 and moisture, O 2, or it may function as a pinning center, and is, for example, Ni. Finally, the outer surface is covered with the insulating material 7 and used as a wire.

As the metal substrate 4, for example, in the case of MgB 2, one that does not react thermally is preferable. For example, Al, stainless steel, duralumin, Cu, Fe, etc. If it is not coiled into a spiral, a ceramic material such as Si can be used. In the case of Y-system, it is desirable to use Hastelloy, Ni-W, etc., since orientation is required. Also in the case of a Cu thin film, a suitable substrate can be used.

For example, the thin film thickness of the thin film superconducting material is desirably about 0.1 to 30 μm. If it is less than 0.1 μm, the percentage of MgB 2 when it is made into a wire decreases. Although a thicker thickness is better, there are problems such as an increase in production time, so it is preferable to make the thickness at 30 μm or less.

The thickness of the protective film 6 is preferably 0.1 to 0.3 nm. The performance depends on the thickness of the thin film MgB2, but if the ratio of the thickness of the protective film to the thickness of the thin film MgB2 is high, high Jc can not be obtained.
In addition, when the thickness is thin, deterioration due to oxidation or mechanical operation of the MgB 2 film becomes large at the time of lamination.

The substrate thickness is preferably 10 μm to 1 mm. If the substrate thickness is large, the proportion of the superconducting material per wire cross-sectional area decreases, so it is preferable to select appropriately under the conditions to be used.

FIG. 3 shows an example in which a plurality of stator units 12 are combined to create an annular stator core. Each stator unit 12 is provided with a slot 2 and an open portion 10 communicating the slot 2 with the space on the inner peripheral side of the stator core in the direction toward the inner peripheral side when the annular stator core is formed. Prepare. The thin film conductor is inserted from the open portion 10. The open part 10 may be provided not on the inner circumferential side but on the outer circumferential side. In this example, two thin film conductors are inserted (one in two). A hook-shaped connecting portion 9 is provided on the upper portion of the stator unit 12 and inserted into the connecting portion insertion port 11 of the adjacent stator unit 12 to connect the stator units 12 with each other to connect the stator core. Form. The number and the position of the connection portions 9 are not limited to those shown in the drawings, as long as the stator units 12 can be connected to each other.

FIG. 4 is a top view of the stator core. The slot 2 as shown in the figure may be provided in the stator core, and the folded portion of the thin film conductor may be inserted from the top to the bottom of the stator core. That is, the thin film conductor 3 may penetrate the stator core 1 in one slot 2. In this case, since it is only necessary to insert the folded portion of the thin film conductor 3 into each slot from one surface side of the stator core 1, it can be easily manufactured. Although the slots are provided radially from the center of the core in FIG. 4, they may be provided obliquely in the direction in which the rotor rotates.

The stator core is usually made of iron, but when using a superconducting material, it does not have to be an iron core because it can generate a strong magnetic field. For example, a common insulating material as a thin film conductor support You may use it. Thereby, the weight of the stator can be further reduced.

For example, when the stator according to the present embodiment is used for a superconducting motor, a rotating magnetic field is generated by flowing alternating current whose phases are sequentially shifted to a plurality of superconducting wire armatures provided in the stator, and a rotor The driving force is generated by the attractive force and the repulsive force. For example, a rotating magnetic field is generated by sequentially flowing U, V, and W phases of three-phase alternating current along a circumference of a plurality of superconducting wires. FIG. 5 shows an example in which thin film conductors which respectively flow U, V and W phases are arranged in an overlapping manner. The width of the slots may be adjusted accordingly to allow the rotor to rotate smoothly.

For example, the invention can also be used for a generator. In a conventional wind power generator, a permanent magnet rotates a rotor installed on the outer peripheral side by wind power to generate current by generating current in a stator armature, but a distributed winding armature winding using the present invention The generated current can be used without loss by using. In addition, since the stator can be miniaturized, the generator itself can also be miniaturized. Instead of the permanent magnets of the rotor, electromagnets can be used. A superconducting coil can also be used.

The invention can also be used for a rotor. Even if it is used for a rotor, it can be miniaturized.

As a combination of the stator of the present invention, a superconducting stator-permanent magnet rotor, a superconducting stator-electromagnetic rotor, a superconducting stator-superconducting rotor, etc. are possible.
(Describe the features of the combination)
In addition, when the present invention is used for a rotor, a combination of a copper wire stator and a superconducting rotor is possible. Combinations other than those described herein can also be used.
The method of forming the thin film MgB2 will be described in detail below. As a substrate, a duralumin plate having a thickness of 500 μm was used. The substrate was mounted on a substrate holder, and a film of MgB 2 was formed by PLD (laser ablation) method. MgB2 was produced as follows. Magnesium powder (purity 99.9%) and granular boron (purity 99.5%) were weighed so that the molar ratio of magnesium to boron was 1: 2, and mixed using a grinder for 120 minutes. The resulting mixture was heat-treated at 900 ° C. for 10 hours in an argon atmosphere to obtain MgB 2. This MgB2 pressed tablet was used as a target. The target was irradiated with a laser of 1 to 5 J / cm 2 at room temperature in an argon atmosphere to form a film. After film formation, the film was annealed at 300 to 800 ° C. for 1 hour and cooled to room temperature. Although not clear diffraction peaks, it was confirmed by X-ray diffraction that the obtained film is MgB2. The prepared thin film MgB2 has a thickness of 0.1 cm, a width of 0.2 cm, and a length of 10 cm. The obtained thin film MgB2 was cut by a laser as shown in FIG. 2 so as to have a predetermined width.

Reference Signs List 1 stator core 2 slot 3 thin film conductor 4 metal substrate 5 conductive material 6 protective film 7 insulating material 8 conductive film forming plate 9 connection portion 10 ... open part, 11 ... connection part insertion port, 12 ... stator unit

Claims (9)

Fixing a rotating electrical machine comprising an annular stator core having a plurality of slots extending circumferentially from the upper surface to the lower surface, and a winding inserted in the plurality of slots and wound around the stator core In the stator, the winding is formed of a thin film conductor, and the thin film conductor is not welded between one end and the other end of the winding which is a current extracting portion, and the upper surface and the lower surface of the stator core A stator of a rotating electrical machine, comprising: a continuous portion penetrating three or more times through the plurality of the slots between them. 2. The plurality of slots according to claim 1, wherein one opening of one slot, the other opening of the one slot, the other opening of the other slot adjacent to the one slot, the other slot The stator for a rotating electrical machine, wherein the thin film conductor is inserted in the order of the other opening. 2. The thin film conductor according to claim 1, wherein the thin film conductor is inserted from one opening of one of the plurality of slots toward the other opening of the one slot, and the one side of the other opening of the one slot is inserted again. The stator of a rotating electrical machine, wherein the thin film conductor is inserted toward an open port of the motor. In Claim 1, a plurality of said slots are provided radially from the ring center of said stator core, and are provided with the open part which connects with either the inner peripheral side or the outer peripheral side of said stator core, and said open part The stator of a rotating electrical machine, wherein the thin film conductor is inserted therein. In Claim 1, a plurality of said slots are prismatic pillars provided radially from the ring center of said stator core, and said thin film conductor goes to the other opening from one opening of said slot. A stator of a rotating electrical machine characterized in that it is inserted. The stator according to claim 1, wherein the thin film conductor is a superconducting material. The stator according to claim 1, wherein the thin film conductor comprises a metal substrate and an MgB2 thin film formed on the metal substrate. The stator according to claim 1, wherein the thin film conductor is a Cu foil. A rotating electrical machine comprising the stator according to claim 1 and a rotor.

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