JPH0719692B2 - Superconducting coil - Google Patents

Description

The present invention relates to an annular forced cooling type superconducting coil, and more particularly to a superconducting toroidal magnetic field coil in a fusion reactor.

[Conventional technology]

In a fusion reactor, a plurality of superconducting toroidal magnetic field coils (hereinafter abbreviated as toroidal coils) formed in an annular shape surrounding a vacuum container are arranged in a donut shape in order to confine plasma in the donut-shaped vacuum container. A toroidal magnetic field having a high magnetic flux density that circulates in a vacuum container in a donut shape is generated.

FIG. 5 is a partially crushed side view showing the schematic structure of the toroidal coil. In the figure, 1A, 1B and 1C are metal plates of a plurality of layers made of a metal material having high rigidity, and are formed in a flat plate ring shape having a hole 2 through which a donut-shaped vacuum container penetrates in the central portion, and the inner peripheral side thereof. By applying a tightening load in the stacking direction of the metal plates through the insertion holes 3 of the plurality of tightening bolts formed on the outer peripheral side and the outer peripheral side, respectively, the coil support 1 having a high rigidity, which is a stack of the metal plates, is formed. It is formed. In addition, a coil housing groove 4 extending over the metal plates on both sides of the metal plate is formed in a spiral shape around the hole 2 along the stack surface, and the superconducting coil conductor is housed in the spiral shape in the spiral shape. As a result, a plurality of layers of coils (layer coils) 5A, 5B, etc. are formed.

In addition, the coils 5 adjacent to each other via the metal plate 1B
A and 5B are connected in series by an inner peripheral crossover portion 6 which passes through a hole penetrating the metal plate 1B on the inner peripheral side thereof to form a two-layer coil 5 commonly called double pancake winding. Further, the outer peripheral side end of each layer coil is pulled out to the outside through a hole penetrating the metal plate in the radial direction.
Is formed. Multiple sets of double pancake winding coils 5
Are connected in series by connecting the lead-out portions 7 to each other to form a superconducting coil 10 in which a plurality of sets of double pancake winding coils 5 are connected in series. The toroidal coil configured as described above is housed in a strong coil container (not shown), and a plurality of toroidal coils are also attached to a vacuum container (not shown).
Generate 100.

Since a pulsed poloidal magnetic field 110 shown by an arrow in the figure is applied to each metal plate of the toroidal coil from a poloidal magnetic field coil (not shown), in order to reduce eddy current loss generated in the metal plate due to this magnetic field change, A thin insulating layer is formed on each laminated surface.

FIG. 6 is a cross-sectional view showing the superconducting coil conductor, and the superconducting coil conductor 11 has a conduit pipe 13 having an insulating coating 12.
A large number of superconducting wires 14 are stored inside, and the insulation coating 12
Is electrically insulated from the metal plate by
By flowing helium 9 as a refrigerant through the conduit pipe 13, the superconductivity of the superconducting wire 14 is maintained.

[Problems to be Solved by the Invention]

An exciting current is supplied to the superconducting coil 10 in order to generate a toroidal magnetic field.
An abnormal voltage that exceeds In the conventional device, since the laminated body 1 of the metal plates is maintained at the ground potential, the superconducting coil conductor 11 has the insulating coating 12 as a thickness capable of withstanding a voltage of 20 KV or more over its entire length. It is necessary to maintain the withstand voltage performance between the metal plate and the laminate 1. In the toroidal coil configured as described above, the cross-sectional area of the insulating coating 12 occupying the coil housing groove 4 becomes large, which causes the space factor of the superconducting wire 14 in the superconducting coil conductor 11 to decrease, which causes There is a drawback that the magnetic flux density of the toroidal magnetic field 100 decreases.

An object of the present invention is to reduce the thickness of the insulating coating layer of the superconducting coil conductor by causing a part of the abnormal voltage to be shared between the metal plates, and at the same time, to provide a metal having an insulation performance capable of withstanding the burden voltage between the metal plates. To obtain an inter-plate insulating layer.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, according to the present invention, a laminated body of metal plates formed in a flat plate ring shape, a coil storage groove formed in a spiral shape along the laminated surface, and a coil storage groove A plurality of layers of coils having an insulating coating housed therein, wherein each layer coil adjacent to each other is alternately connected in series by the inner circumference side crossover section and the outer circumference side crossover section, wherein the metal plate is on its laminated surface. A pair of metal plates sandwiching each layer coil while being insulated and fixed to each other by an insulating layer between metal plates made of a cured product of a laminated material of an interposed plastic film and thermosetting prepreg sheets arranged on both sides thereof. One of which is held at the same electric potential as the outer peripheral side connecting portion and the other is held at the same electric potential as the inner peripheral side connecting portion, or a metal formed in a flat plate ring shape. Rate laminated body, a coil accommodating groove formed in a spiral shape along the lamination surface, and a plurality of layers of coils having an insulating coating accommodated in the coil accommodating groove. In a structure in which a peripheral crossover portion and an outer peripheral crossover portion are alternately connected in series, the metal plate is formed of an annular plastic molding material having a cross section that covers one side of a laminated surface of the metal plate over the coil storage groove. Are insulated from each other by the insulating layer between the metal plates, and one of the pair of metal plates sandwiching each layer coil is held at the same potential as the outer peripheral side connecting portion and the other is held at the same electric potential as the inner peripheral side connecting portion. It has been done.

[Action]

In the above means, the potentials of the pair of metal plates sandwiching each layer coil are made equal to the potentials of the transition portion and the lead-out portion of both ends of each layer coil, so that the potential difference between each layer coil and the pair of metal plates is shared by each layer coil. It is reduced to a value equivalent to the voltage. Therefore, the thickness of the insulating coating of the superconducting coil conductor can be significantly reduced, and the space factor of the superconducting wire can be increased by that much, so that the magnetic flux density of the toroidal magnetic field can be increased.

On the other hand, since it becomes necessary to strengthen the insulation between the metal plates by giving a potential difference to the metal plates, a layered material with the plastic film as the central layer and the thermosetting prepreg sheet as the outer layer is laminated on the metal plates. The prepreg sheet is placed on the surface and heat-cured with a tightening load applied to the laminated body of the metal plates to form a cured insulating layer with no gaps by the thermosetting resin once melted, and the metal plate. Since the mutual and superconducting coil conductors are fixed to each other, an inter-plate insulating layer having excellent withstand voltage performance and mechanical strength is obtained. Further, when a plastic molding material that covers one laminated surface of the metal plate over the coil storage groove is interposed, the plastic molding material and the insulating coating of the superconducting coil are overlapped with each other in the coil storage groove. High withstand voltage performance can be easily obtained, and by using a plastic molding material as a composite material that has thermosetting prepreg sheet layers on both sides of the plastic molding material, an inter-plate insulating layer with higher insulation performance and mechanical strength can be obtained. It can be easily formed.

〔Example〕

 The present invention will be described below based on examples.

FIG. 1 is a sectional view showing a simplified essential part of a toroidal coil according to an embodiment of the present invention. Detailed description will be omitted by using the same reference numerals for parts having the same structure and function as those of the conventional device. In the figure, the toroidal coil is
An example in which three superconducting coils 10 are formed by stacking three sets of double pancake winding coils 5 in which 5A and 5B two-layer coils are connected in series by a crossover portion 6 on the inner peripheral side (shown in a simplified manner with broken lines in the figure) And each layer coil 5A, 5B of n = 6 layers is 1A
From 1 to 1 G, the coil is housed in a coil housing groove 4 formed in a spiral shape along each stacking surface of a stack 1 of a total of 7 metal plates. In addition, the three sets of double pancake winding coils 5 have outer peripheral side connecting portions 17 that electrically connect the outer peripheral side drawing portions 7 to each other.
Thus, a superconducting coil 10 is formed which is connected in series and a voltage V is applied between both terminals.

Further, 21 is a power feeding portion for keeping the outer peripheral side draw-out portion 7 or connection portion 17 and the metal plate at the same potential, and 22 is a power feeding portion for keeping the inner circumferential side connecting portion 6 and the metal plate at the same potential. The metal plates adjacent to each other are conductively connected to the superconducting coil 10 alternately on the outer circumference side and the inner circumference side, so that the maximum potential difference between each layer coil and the metal plates on both sides thereof (the voltage burdened by the insulation coating 12). ) Is equal to the shared voltage of each layer coil. That is, looking at one coil 5A of the double pancake winding coil 5, the maximum potential difference between the layer coil 5A and the metal plate 1A is equal to the shared voltage V / n of the coil 5A at the inner end of the coil 5A. The maximum potential difference between 5A and the metal plate 1B is equal to the shared voltage V / n of the coil 5A at the outer end of the coil 5A.

In this way, the maximum potential difference between each layer coil and the pair of metal plates sandwiching it is reduced to 1 / n of that of the conventional device. That is, in the device of the embodiment, the voltage V between both terminals is
With 20KV, the withstand voltage performance required for the insulation coating 12 of the superconducting coil conductor 11 is 1/6 that of the conventional device of 20KV.
It will be reduced to 3.3KV, which is equivalent to, and the thickness of the insulation coating can be greatly reduced. Therefore, the diameter of the conduit pipe 13 is increased without changing the size of the coil housing groove, the total cross-sectional area of the superconducting wire 14 housed therein is increased, and the magnetic flux density of the toroidal magnetic field 100 is increased in proportion to this. To do.

On the other hand, by applying the electric potential of the superconducting coil to each metal plate, the coil 1 is also applied between the metal plates adjacent to each other.
A potential difference for each layer is generated, and a potential difference is also generated between the connecting bolt 30 and each metal plate. Therefore, insulating means such as interposing an inter-plate insulating layer 40 that withstands a potential difference on the laminated surface of each metal plate and insulating the tightening bolt 30 is provided. Although the thickness of the inter-plate insulating layer 40 becomes thicker than that of the insulating coating conventionally provided to prevent eddy current loss, even if the depth of the coil housing groove 4 formed in a spiral shape on the metal plate is reduced accordingly. Since the cross-sectional area of the groove can be maintained at the same level as the conventional one, the size of the laminated body 1 of the metal plate as the coil support can be maintained as usual without lowering the mechanical strength of the metal plate, and a high magnetic flux density can be obtained. A superconducting toroidal coil that can generate a toroidal magnetic flux can be obtained.

Next, the structure of the inter-plate insulating layer will be described.

FIG. 2 is an enlarged sectional view of an essential part showing an inter-plate insulating layer of the embodiment, and FIG. 3 is a sectional view of an inter-plate insulating material. As shown in FIG. 3, the insulating material used is a plastic film, such as a polyimide film having a thickness of about 25 μm, for the central layer 42.
As a layered material 41 using a thermosetting prepreg sheet that is semi-cured by impregnating both layers 43A and 43B with a glass cloth or glass non-woven fabric having a thickness of about 0.1 mm with a polyimide resin varnish. Showing metal plate eg 1A, 1
It is installed on the flat laminated surface of B. The width of the laminated material 41 is such that both ends in the width direction are in contact with the insulating coating 12 of the adjacent superconducting coil conductors 11, the winding materials are arranged in a spiral shape along the stacking surface, and the metal plate is formed by the insulating coated tightening bolt 30. With a tightening load applied to the laminated surface of the
It heats at 0 degreeC and heat processing is performed for about 2 hours. At this time,
The semi-cured polyimide resin once melts to increase fluidity, fills the gap between the metal plates, and also fills the gap with the insulating coating layer 12 of the coil conductor. The insulating layer 40 is an insulating coating layer
Integrating with 12 to obtain excellent withstand voltage performance,
Adjacent metal plates and coil conductors 11 are fixed to each other via the inter-metal plate insulating layer 40, and a superconducting coil that is mechanically strong and has excellent thermal conductivity can be obtained.

If the voltage applied between the metal plates is large,
Both side layers 43 may be a composite material of a resin laminated plate and a prepreg sheet, and the edge of the insulating layer protruding to the outer peripheral side or the inner peripheral side of the metal plate may be preliminarily bent along the side surface of the metal plate. .

FIG. 4 is an enlarged cross-sectional view of the essential part showing the structure of the inter-metal plate insulating layer of a different embodiment. One of the pair of metal plates sandwiching the pancake winding coil, for example 5A, between the inter-plate insulating layer 50, for example 1A, is shown in FIG. It is different from the above-mentioned embodiment in that it is constituted by plastic molding materials 51, 52, 53 and the like which cover the coil housing groove 4 over. That is, in the metal plate 1A, a roundness having a radius of curvature r is formed along the storage groove 4 at the boundary portion between the flat laminated surface and the semicircular coil storage groove 4, and the plastic molding material extends across the laminated surface over the storage groove. It is preformed into an annular or spiral shape having a cross-sectional shape close to the hollow shape, and is mounted with a gap 59 held in the storage groove.

As a plastic molding material, a thermosetting resin plate such as a polyimide resin plate, a silicone resin plate, or an epoxy resin plate having a thickness capable of withstanding a voltage between plates is thermocompression-molded by using a heat press die, or a polyimide film is formed in a central layer. A glass woven or glass non-woven fabric based polyimide prepreg sheet is used as a layer on both sides at a temperature of 150
By using a heat press at about ℃, which is formed in a semi-cured state by forming into a square shape,
The inter-plate insulating layer 50 is formed by incorporating the layer coils 5A and 5B into the coil support 1 made of a laminated body of metal plates. In particular, when using a plastic molding material consisting of a semi-cured layered material, for example, 230 ℃,
The polyimide resin fills the gaps in the same manner as in the above-mentioned embodiment by the heating and curing treatment for about 2 hours, and the insulating coating layer 12 and the inter-plate insulating layer 50 are integrated while maintaining mutual overlap, so that the extremely high resistance is achieved. A superconducting coil having voltage performance and mechanical strength can be obtained. Further, since the inter-plate insulating layer can be formed by a simple work of mounting the preformed components along the coil housing groove, there is an advantage that the work of laminating the metal plates can be saved.

〔The invention's effect〕

As described above, the present invention applies the electric potential of the coil crossing part to the metal plate holding the pancake winding coil, and the insulating layer between the metal plates having different electric potentials is cured and insulated from the laminated material of the plastic film and the thermosetting prepreg sheet. The layer or the laminated surface of the metal plate is formed of an annular plastic molding material having a cross section that covers the coil storage groove. as a result,
The potential difference between the pancake-wound coil and the pair of metal plates sandwiching it is reduced to a fraction of the number of coil layers with respect to the conventional total voltage, and based on this, the coating thickness of the coil conductor is reduced. The cross-sectional area of the superconducting coil conductor can be increased, and thus a superconducting coil that can generate a toroidal magnetic field with a high magnetic flux density can be provided. In addition, when a laminated material is used as the insulating layer between metal plates, the gap between the laminated surfaces is filled with the thermosetting resin whose fluidity is increased by heating the entire superconducting coil, and at the same time the insulating coating of the coil conductor is formed. Since the inter-plate insulating layer is integrated, it forms an inter-plate insulating layer with high withstand voltage performance that does not include voids or voids, and the metal plate and pancake winding coil are bonded to each other through the inter-plate insulating layer. Therefore, a superconducting coil having excellent mechanical and thermal characteristics can be obtained. Furthermore, when a plastic molding material is used, the mounting of the molding material on the metal plate is facilitated, the work of assembling the inter-plate insulating layer and the metal plate is saved, and the molding material is not formed in the coil storage groove. Since the conductor insulation coatings overlap each other, the withstand voltage performance can be further improved, and the inter-plate insulating layer that is voided by adding a prepreg sheet to the molding material can be easily formed by a labor-saving work process. can do.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment device of the present invention, FIG. 2 is an enlarged cross-sectional view showing an inter-plate insulating layer of the embodiment device, and FIG.
The figure is a cross-sectional view showing the structure of the inter-plate insulating layer, FIG. 4 is an enlarged cross-sectional view showing the structure of different plate insulating layers, FIG. 5 is a partially crushed cross-sectional view showing the conventional structure, and FIG. 6 is a superconducting coil conductor. FIG. 1: Coil support (laminate of metal plates), 1A, 1B, 1C:
Metal plate, 2: Through hole, 4: Coil storage groove, 5A, 5B: Pancake winding coil, 5: Double pancake winding coil, 6:
Inner circumference side crossing section, 7: Lead-out section, 10: Superconducting coil, 11: Superconducting coil conductor, 12: Insulating coating layer, 17: Outer side connecting section (crossing section), 21, 22: Power feeding section, 30: Tightening Bolts, 40, 50: Insulation layer between metal plates, 41: Laminated material, 42: Central layer (plastic film), 43A, 43B, 43: Both layers (prepreg sheet), 51, 52, 53: Plastic molding material, 59 : Void.

Claims (2)

[Claims] 1. A plurality of layers having a laminated body of metal plates formed in a flat ring shape, a coil accommodating groove formed in a spiral shape along the lamination surface, and an insulating coating accommodated in the coil accommodating groove. Of the above-mentioned coil, wherein each layer coil adjacent to each other is alternately connected in series by an inner peripheral side connecting portion and an outer peripheral side connecting portion, the plastic plate having the metal plate interposed on its laminated surface and both sides thereof. Insulated and fixed to each other by an insulating layer between metal plates made of a cured product of a laminated material with a thermosetting prepreg sheet arranged in, and one of a pair of metal plates sandwiching each layer coil and the outer peripheral side transition portion. A superconducting coil, wherein the superconducting coil is held at the same potential, and the other is held at the same potential as that of the inner peripheral side transition portion. 2. A plurality of layers having a laminated body of metal plates formed in a flat ring shape, a coil accommodating groove formed in a spiral shape along the lamination surface, and an insulating coating accommodated in the coil accommodating groove. In which each layer coil adjacent to each other is alternately connected in series by the inner circumference side crossover section and the outer circumference side crossover section, the metal plate straddles one side of the lamination surface into the coil storage groove. Are insulated from each other by an insulating layer between metal plates made of an annular plastic molding material having a cross section covering up to each other, and one of a pair of metal plates sandwiching each layer coil is held at the same potential as the outer peripheral side crossing portion, A superconducting coil, characterized in that the other is held at the same potential as the inner peripheral side crossing portion.