A method for arranging voltage leads of a non-insulated coil and the coil

Abstract

The present invention discloses a method for arranging voltage leads of a coil without insulation and a coil, relating to the field of superconducting technology. The method includes: S1, obtaining superconducting tape and a foil-type voltage sensor; S2, winding a coil without insulation by using the superconducting tape; S3, inserting the foil-type voltage sensor between the superconducting tapes of the coil without insulation being wound in S2, so as to obtain a coil without insulation with the foil-type voltage sensor arranged therein. The present invention can measure the voltage inside the coil without affecting the inter-turn contact performance of the coil without insulation.

Description

Technical Field

[0001] The present invention relates to the field of superconducting technology, and in particular, to a method for arranging voltage leads of a coil without insulation and a coil. Background Art

[0002] The coil without insulation was first proposed by Hahn et al. from MIT. The traditional insulation between coil turns is removed. Since the superconducting material has zero resistance, while the metal interface between turns has a relatively high resistance compared to the superconducting material, the current will ultimately still flow in a circumferential direction. In a coil without insulation, if there are defect points on the tape or local hot spots are generated during a quench, the current can bypass the defect points or hot spots through the turns, thus not causing heat accumulation. In addition, since the insulation material is removed, the thermal conductivity between the tape and the metal will be better, which can take away the heat in time and thus will not induce a larger-scale quench, and can reduce the size of the coil, greatly improving the engineering current density of the coil without insulation. Therefore, the coil without insulation can achieve a high current density while having good stability, and has broad prospects in many high magnetic field applications.

[0003] In the test technology of coils without insulation, many sensors are used to monitor whether the coil quenches. Among them, the voltage sensor is a typical sensor. When the superconducting material quenches, it will become a normal conductor and have resistance characteristics, and a non-zero voltage will appear on the conductor, which is the most effective means to detect quenches. In voltage sensors, the current conventional method is to weld voltage leads on the surface or side of the tape. The voltage leads generally use metal wires or metal probes, such as copper wires, manganin wires, phosphor bronze wires, copper probes, etc. In order to be able to understand the operating conditions of the coil more accurately, it is often necessary to arrange multiple distributed voltage sensors on the coil. Especially for coils without insulation, when there is inter-turn shunting, the local voltage may change, and it is impossible to detect only by the voltage leads of the outermost turn of the coil. Jeseok Bang et al. proposed a method of directly welding voltage leads on the upper surface (i.e., the side of the tape) of a pancake coil. However, this method has high requirements for the fixing process. For example, welding will change the inter-turn resistance, and if ordinary tape is used for fixing, the leads are prone to breakage.

[0004] Therefore, it is an urgent problem for those skilled in the art to propose a method for arranging voltage leads of a coil without insulation and a coil, which realizes voltage measurement under the condition of extremely weakly changing the coil geometry by inserting foil-shaped conductors between turns during the coil winding process. Summary of the Invention

[0005] In view of this, the present invention provides a method for arranging voltage leads of a coil without insulation and a coil, which can solve the problems existing in the prior art.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for arranging voltage leads of a non-insulated coil, comprising the following steps:

[0008] S1. Obtain a superconducting tape and a foil-type voltage sensor;

[0009] S2. Wind a non-insulated coil with the superconducting tape;

[0010] S3. Insert the foil-type voltage sensor between the superconducting tapes of the non-insulated coil being wound in S2 to obtain a non-insulated coil arranged with the foil-type voltage sensor.

[0011] In the above method, optionally, the superconducting tape in S1 adopts a REBCO superconducting tape, and the foil-type voltage sensor adopts a conductive foil.

[0012] In the above method, optionally, in S2: the non-insulated coil is a non-insulated pancake coil.

[0013] In the above method, optionally, the specific content of S3 includes:

[0014] S31. Starting from the first turn, when winding to the Nth turn, insert the foil-type voltage sensor, and fix the foil-type voltage sensor between the Nth turn and the (N - 1)th turn by the extrusion of the superconducting tapes between the two turns;

[0015] S32. Repeat S31 and continue to wind to the position of the next preset voltage lead point; so that a preset number of foil-type voltage sensors are all fixed by the extrusion between adjacent two turns.

[0016] In the above method, optionally, the position of the preset voltage lead point, that is, the placement position of the foil-type voltage sensor, is determined according to the geometric shape of the non-insulated coil, and specifically includes the following content:

[0017] The non-insulated coil is a circular coil, which is axisymmetric, and the placement position of the foil-type voltage sensor is not restricted;

[0018] If the non-insulated coil is a racetrack-type coil or a D-type coil, then the foil-type voltage sensors are respectively placed in the straight section and the curved section to explore the voltage signal changes at different positions.

[0019] In the above method, optionally, the foil-type voltage sensor selects graphite.

[0020] A non-insulated coil with voltage leads obtained by using the method described in any one of the above, comprising a non-insulated coil wound by a superconducting tape, and a foil-type voltage sensor is arranged between the superconducting tapes of the non-insulated coil.

[0021] As can be seen from the above technical solutions, compared with the prior art, the present invention discloses a method and a coil for arranging voltage leads without insulation coils, having the following beneficial effects: when winding the coil, a conductive foil with high strength and extremely low thickness is inserted between turns and fixed by the extrusion of adjacent two turns. The traditional voltage leads can only be welded to the surface of the strip by soldering and cannot be arranged inside the coil. However, this foil-type voltage lead can be placed between two strips with an extremely thin thickness by means of pressure contact, and can measure the voltage inside the coil without affecting the inter-turn contact performance of the non-insulated coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0023] Figure 1 It is a flowchart of a method for arranging voltage leads of a non-insulated coil disclosed by the present invention;

[0024] Figure 2 It is an illustration of the position where the foil-type voltage sensor is placed when winding the coil disclosed by the present invention;

[0025] Figure 3 Disclosed by the present invention Figure 2 Cross-sectional view of the arrangement of the foil-type voltage sensor of the non-insulated coil;

[0026] Figure 4 It is a physical picture of the arrangement of the foil-type voltage leads of the non-insulated coil disclosed by the present invention. Among them, 4a is the physical picture of the arrangement diagram of the connecting wire, and 4b is the physical picture of the arrangement diagram without the connecting wire;

[0027] Among them, 1 - superconducting strip, 2 - non-insulated coil, 3 - foil-type voltage sensor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0029] In this application, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. The terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0030] Referring to Figures 1-3 As shown, the present invention discloses a method for arranging voltage leads without an insulating coil, comprising the following steps:

[0031] S1. Obtain a superconducting tape 1 and a foil-type voltage sensor 3;

[0032] S2. Wind a non-insulated coil 2 with the superconducting tape 1;

[0033] S3. Insert the foil-type voltage sensor 3 between the superconducting tapes 1 of the non-insulated coil 2 being wound in S2 to obtain a non-insulated coil 2 with the foil-type voltage sensor 3 arranged therein.

[0034] Further, the superconducting tape 1 in S1 uses a REBCO superconducting tape, and the foil-type voltage sensor 3 uses a conductive foil.

[0035] Among them, the REBCO superconducting tape: a second-generation high-temperature superconducting tape, having superconducting properties, capable of being wound into a coil for strong magnetic field applications; the non-insulated coil: directly wound with a REBCO superconducting tape without using any insulation, and wound into a pancake coil; the foil-type voltage sensor: a relatively thin conductive foil, or a relatively thin superconducting tape, with a thickness of about 0.01 - 0.05 mm, and selected according to different application scenarios.

[0036] Further, in S2: the non-insulated coil 2 is a non-insulated pancake coil.

[0037] Further, the specific content of S3 includes:

[0038] S31. Starting from the first turn, when winding to the Nth turn, insert the foil-type voltage sensor 3, and fix the foil-type voltage sensor 3 between the Nth turn and the (N - 1)th turn by squeezing with the superconducting tapes between the two turns.

[0039] S32. Repeat S31 to continue winding the positions of the next preset voltage lead points, so that the preset number of foil-type voltage sensors 3 are all fixed by the extrusion between adjacent turns.

[0040] Furthermore, the positions of the preset voltage lead points, that is, the placement positions of the foil-type voltage sensors 3, are determined according to the geometric shape of the non-insulated coil 2, specifically including the following:

[0041] If the non-insulated coil 2 is a circular coil and is axisymmetric, there is no restriction on the placement position of the foil-type voltage sensor 3.

[0042] If the non-insulated coil 2 is a racetrack-shaped coil or a D-shaped coil, then the foil-type voltage sensors 3 are placed on the straight section and the curved section respectively to explore the voltage signal changes at different positions.

[0043] Specifically, the number of turns to be placed is determined according to the actual test requirements. For example, in this experiment, one is placed every 10 turns. In some other experiments, if precise measurement is required, one can be placed every 1 turn. The optimal number of turns is determined according to the actual application.

[0044] Furthermore, the foil-type voltage sensor 3 is made of graphite.

[0045] The selection of the foil is not limited to graphite sheets, copper sheets, aluminum sheets, stainless steel sheets, etc. Any conductive material that meets the requirements of high strength and thin thickness can be selected as the foil voltage lead. At the same time, the number of foils inserted theoretically has no upper limit and can be arranged at any position of the coil according to needs. A reasonable arrangement of the foil-type voltage leads can better measure and monitor the coil.

[0046] Specifically, this method has very high requirements for the foil. To measure the voltage, the foil needs to be made of a conductive material. First of all, it is required that the foil be very thin and not affect the winding of the non-insulated coil, and there should be no obvious gaps between adjacent turns, and good contact between adjacent turns and a sufficiently small inter-turn resistance should be ensured. Therefore, the thickness of the foil needs to be controlled below 0.05 mm. In addition, the foil should have good friction. Since the foil is fixed by the friction generated by the extrusion between turns, if the friction is too small, the foil may slip out from the inter-turn gap. Finally, the foil should have high strength. Generally, foils with a thickness below 0.02 mm, even if they are made of metal materials, are very fragile and easy to tear and break. Therefore, high-strength foil materials need to be selected.

[0047] In a specific embodiment, the foil is made of high-purity material to produce a graphite sheet with a thickness of 0.01 - 0.05 mm.

[0048] In another specific embodiment, the foil is a copper sheet with a thickness of 0.03 - 0.05 mm, or an aluminum sheet with a thickness of 0.02 - 0.05 mm, or a stainless steel sheet with a thickness of 0.01 - 0.05 mm.

[0049] See Figure 2 As shown, the present invention also discloses an insulated coil without insulation with voltage leads obtained by using any of the above - described methods, including an insulated coil without insulation 2 wound by a superconducting tape 1, and a foil - type voltage sensor 3 is arranged between the superconducting tapes 1 of the insulated coil without insulation 2.

[0050] In a specific embodiment, see Figure 4 Shown is an insulated coil without insulation with voltage leads wound according to the scheme of the present invention, wherein, Figure 4 a is a physical picture of the layout diagram of the connecting wires, Figure 4 b is a physical picture of the layout diagram without connecting wires.

[0051] When winding the coil, a high - strength and extremely thin conductive foil is inserted between turns and fixed by the extrusion of adjacent turns. Traditional voltage leads can only be soldered on the surface of the tape and cannot be arranged inside the coil. However, this foil - type voltage lead can be placed and led out between two tapes with an extremely thin thickness by relying on the pressure - contact method, and can measure the voltage inside the coil without affecting the inter - turn contact performance of the insulated coil without insulation.

[0052] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for a system or a system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and for the relevant parts, reference can be made to the partial description of the method embodiment. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0053] The foregoing description of the disclosed embodiments enables those skilled in the art to practice or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for arranging voltage leads without an insulation coil, characterized in that: The following steps are involved: S1. Obtain superconducting tape and foil voltage sensor; S2, using superconducting tape to wind uninsulated coils; S3, inserting the foil type voltage sensor between the superconducting tapes of the non-insulated coil being wound in S2, to obtain the non-insulated coil arranged with the foil type voltage sensor; In S2: the uninsulated coil is an uninsulated pancake coil; The specific contents of S3 include: S31, starting from the 1st turn, inserting the foil voltage sensor when winding to the Nth turn, and fixing the foil voltage sensor between the Nth turn and the N-1th turn by squeezing the superconducting tape between the two turns; S32, repeat S31, and continue to wind the position of the next preset voltage lead point, so that the preset number of foil voltage sensors are fixed by squeezing between two adjacent turns.

2. The method for arranging voltage leads of a non-insulated coil according to claim 1, characterized in that: The superconducting tape in S1 uses REBCO superconducting tape, and the foil voltage sensor uses conductive foil.

3. The method for arranging voltage leads of a non-insulated coil according to claim 1, characterized in that: The location of the preset voltage lead point, i.e. the placement position of the foil voltage sensor, is determined based on the geometry of the uninsulated coil, including the following: The uninsulated coil is a circular coil, which is axially symmetrical, and there is no restriction on the placement of the foil voltage sensor; If the uninsulated coil is a racetrack-type coil or a D-type coil, foil voltage sensors are placed on the straight section and the curved section respectively to explore the changes in voltage signals at different positions.

4. The method for arranging voltage leads of a non-insulated coil according to claim 1, characterized in that: Foil voltage sensors use graphite sheets.

5. A non-insulated coil with a voltage lead obtained by the method according to any one of claims 1 to 4, characterized in that: The invention comprises a non-insulated coil wound by a superconducting tape, and foil type voltage sensors are arranged between the superconducting tapes of the non-insulated coil.

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