Electromagnetic Coil Assembly

Abstract

The present invention relates to an electromagnetic coil assembly, and more particularly, to an electromagnetic coil assembly including at least a core, a winding wound multiple times around the core to form a coil, and a plurality of power taps for electrically connecting the winding to an external power circuit. Most electromagnetic coils incorporating HTS materials are for academic purposes and are typically hand-wound. These coils require some type of power cable or power tap. Because the field of high-temperature superconductivity is quite new, the state-of-the-art is experiencing rapid change in application areas. Most electromagnetic coils incorporating HTS materials are for academic purposes and are typically hand-wound. These coils require some type of power cable or power tap. However, in academic applications, the coils are typically "disposable" and therefore cannot be manufactured on a large scale, in large quantities, for a sufficiently long period of time. Therefore, it is an object of the present invention to provide an electromagnetic coil assembly incorporating HTS materials that can be mass-produced reliably, robustly, and cost-effectively.

Description

[Technical field]

[0001] The present invention relates to an electromagnetic coil assembly, and more particularly to an electromagnetic coil assembly including at least a core, a winding wound a number of times around the core to form a coil, and a number of power taps for electrically connecting the winding to an external power circuit. [Background technology]

[0002] The above-mentioned electromagnetic coil assembly is disclosed in, for example, Japanese Patent Application Laid-Open No. 2008-305861. Summary of the Invention [Problem to be solved by the invention]

[0003] In general, superconducting coils are widely used in commercial and research applications in medical fields such as NMR and MRI, and in rotating machines such as motors and generators. Meanwhile, cables made from high-temperature superconducting (HTS) wires are known and can carry up to ten times more current than conventional cables. Alternatively, there are HTS cables that can carry the same current at a lower voltage. HTS can be used in both direct current (DC) and alternating current (AC) systems. In general, high-temperature superconducting materials (abbreviated as high T c or HTS) is a type of ferroelectric material that is used for heating at temperatures around -200°C (73.15K), especially for nitrogen (N 2 It is operationally defined as a material that exhibits superconductivity near the boiling point of -196.5°C (=77K).

[0004] The field of high temperature superconductivity is very new, and the state of the art is seeing rapid change in application areas. Most electromagnetic coils implementing HTS materials are for academic purposes and are usually hand wound. These coils require some sort of power cable or power tap. However, for academic applications the coils are usually "disposable" and cannot be manufactured on a large scale, quantitative basis, for a long enough time.

[0005] Accordingly, it is an object of the present invention to provide an electromagnetic coil assembly incorporating HTS materials that is reliable, robust, and cost-effectively mass-producible. [Means for solving the problem]

[0006] To address this problem, an electromagnetic coil assembly is provided that includes a core, a winding wound multiple times around the core to form a coil, and a number of power taps for electrically connecting the winding to an external power circuit, the winding being formed as a tape component comprising a high temperature superconducting (HTS) material, and the multiple power taps being connected to the winding exiting the face of the coil at a predetermined angle.

[0007] Typically, the power taps of known coils are connected to the conductors using solder connections to copper bus bars. When the conductors are formed from tape components containing high temperature superconducting (HTS) material, and multiple power taps are connected to the HTS tape windings, they exit the face of the coil at an angle, allowing a strong and reliable electrical connection between the coil and an external power source or the like.

[0008] The electromagnetic properties of the HTS coil are further improved if the power tap is also made of a superconducting material, i.e. more specifically in this case the power tap is formed as a tape-shaped power tap including a high temperature superconducting (HTS) material, in particular the tape-shaped power tap is made from HTS tape components as windings.

[0009] By way of example, the power tap is connected to the tape winding at an angle α between 30° and 90°, in particular 90°, which increases the contact surface between the HTS tape winding and the tape-like power tap.

[0010] In another advantageous embodiment, the power tap has a curved portion extending from the position where it exits the coil to the position where it is connected to the power terminals of the external power supply circuit. This curvature coincides with the magnetic field lines of the magnetic field generated by the coil during operation. As a result, even when the power tap is exposed to the magnetic field, the disturbance and exposure to electromagnetic force (Lorentz force) caused thereby are minimized.

[0011] In a further embodiment of the HTS coil, the plurality of windings of the coil are composed of N turns, the first power tap is connected to the first turn of the winding, the second power tap is connected to the Mth turn of the winding, and M < N. In particular, the first and second power taps are used to electrically connect the coil and the external power supply.

[0012] In yet another embodiment of the HTS coil, the electromagnetic coil assembly further comprises a plurality of voltage taps for measuring the voltage between at least some of the plurality of turns of the winding, the first voltage tap is connected to the (M + 1)th turn of the winding, the second voltage tap is connected to the Oth turn of the winding, O ≈ N, and in particular O = N. Thereby, the first and second voltage taps can be connected to other types of peripheral devices (more specifically, quench detection or protection systems). Thereby, the potential difference between the (M + 1)th turn and the Oth turn of the winding can be detected. This potential difference is induced by external disturbances of the magnetic field of the electromagnetic coil assembly.

[0013] The electromagnetic coil assembly implementing the HTS tape winding is further characterized by the following specific winding principle. (N - M) / N << 1

[0014] The winding principle of a specific embodiment is represented as follows. 0.01 << (N - M) / N << 0.10

[0015] In yet another embodiment, the average winding from turn 1 to the Mth turn in the plurality of turns lineThe tension is the average winding force from the (M+1)th turn to the Nth turn of multiple turns. line This further improves the performance of the electromagnetic coil assembly. In particular, the M+1th turn to the Nth turn of the second winding section 12b has a higher average winding tension than the 1st turn to the Mth turn of the first winding section 12a. line When tensioned, the inner winding section, consisting of turns [1…M], is confined by the outer winding section, consisting of turns [M+1…N], which also increases the mechanical stability of the coil.

[0016] In one embodiment of the HTS coil assembly, the core is a ferromagnetic core, while in other advantageous embodiments the core is a non-ferromagnetic core.

[0017] In a further advantageous embodiment, each of the power taps comprises a sub-tap, which improves electrical conductivity between the HTS coil assembly and external peripherals, and in particular reduces contact resistance between each sub-tap and the HTS tape windings.

[0018] Advantageously, the HTS material comprises at least one of the group consisting of (RE)BCO, BSCCO, TBCCO. [Brief description of the drawings]

[0019] The invention will now be described in more detail with reference to the accompanying drawings. [Figure 1A] 1A and 1B are diagrams showing a first embodiment of an electromagnetic coil assembly according to the present invention; [Figure 1B] 1A and 1B are diagrams showing a first embodiment of an electromagnetic coil assembly according to the present invention; [Figure 2A] FIG. 2 is a diagram showing a second embodiment of an electromagnetic coil assembly according to the present invention. [Figure 2B] FIG. 2 is a diagram showing a second embodiment of an electromagnetic coil assembly according to the present invention. [Figure 2C]FIG. 2 is a diagram showing a second embodiment of an electromagnetic coil assembly according to the present invention. [Diagram 3] FIG. 3 is a detailed view of the second embodiment of FIG. 2. [Figure 4] 1 is a detailed view of the first and second embodiments.In order to properly understand the present invention, in the following detailed description, corresponding elements or parts are designated by the same reference numerals. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] 1a-1b show a first embodiment of an electromagnetic coil assembly according to the present invention. The electromagnetic coil assembly 10 comprises a core 11 and a winding 12. The winding 12 is made up of a coil wound multiple times around the core 11. Preferably, the core 11 is a ferromagnetic core, although other materials such as non-ferromagnetic cores may be used.

[0021] The coil assembly typically also includes a number of power taps for electrically connecting the winding 12 to external peripherals, particularly an external power source. In this regard, a first power tap 13a and a second power tap 13b connect the winding 12, particularly the first winding section 12a of the winding 12, to an external power source. The first power tap (or first tap) 13a is a positive terminal (+) and the second power tap (or second tap) 13b is a negative terminal (-). Another embodiment of the electromagnetic coil assembly 10' shown in Figure 2a and particularly in Figure 3 includes additional taps connected to the HTS winding 12. These additional taps are shown as a first voltage tap 14a and a second voltage tap 14b and serve to electrically connect the winding 12 to other types of external peripherals, particularly a voltmeter 21, as described below.

[0022] Each of the power taps 13a-13b and voltage taps 14a-14b may include multiple sub-taps 130a-130b and 140a-140b to improve reliability and connectivity.

[0023] Quench detection and protection circuitry connected to the voltage taps 14a-14b of the second winding section 12b of the winding 12 is essential in most coil applications because of the large amount of energy stored in the superconducting coil assembly. If currents of hundreds of amps flow through the windings of the coil assembly and the coil loses its superconductivity, it can lead to a "meltdown" scenario, which is a catastrophic failure of the system. Therefore, a reliable and safe quench detection mechanism is essential in almost all applications.

[0024] As shown in Figures 1-3, the windings 12 are formed as tape components that are narrow relative to their length. Such tape components 12 include a high temperature superconducting (HTS) material. Examples of HTS materials may be at least one of the group consisting of (RE)BCO, BSCCO, and TBCCO. However, the material of the tape components 12 may be other HTS materials.

[0025] As shown in FIG. 1a, the first and second taps 13a-13b (first and second connection taps) are connected to the HTS winding exiting the coil surface at an angle. In the embodiment of FIG. 1a, the first and second connection taps 13a-13b are connected to the HTS winding 12 at an angle of 90°. Another embodiment is shown in FIG. 3, where the first and second taps 14a-14b are connected to the tape winding 12 at a sharper angle α (30°-90°, in particular 70°-85°). The power taps 13a-13b are likewise connected to the tape winding 12 at a sharper angle α (30°-90°, in particular 70°-85°). The second type of taps 14a-14b may also be connected to the tape winding 12 at an angle α=90°.

[0026] The taps 13a-13b; 14a-14b are connected to the HTS winding 12 at an acute angle to provide a proper exit from the winding 12 and a proper and stable electrical connection. An angle α=90° ensures a stable electrical connection with limited stress.

[0027] For the manufacture of such an electromagnetic coil assembly 10-10', a tape winding 12 is wound on a robin or core 11. During the winding step, at least one electrical tap 13a-13b; 14a-14b is connected at a desired angle α (the angle at which these taps exit the plane of the coil 12). Typically, this angle is 90° so that only the angular component in the lead direction remains. However, depending on the specific application, other angles may be useful. In this way, some power taps 13a-13b and voltage taps 14a-14b are mechanically trapped between the windings, ensuring a proper and stable electrical connection.

[0028] Preferably, the voltage taps 13a-13b are made of a superconducting material. In an advantageous embodiment, the voltage taps 13a-13b are formed of tape taps including an HTS material. More specifically, the tape voltage taps 13a-13b are manufactured of the same HTS material as the HTS tape winding 12, which includes at least one of the group consisting of (RE)BCO, BSCCO, TBCCO. However, again, other HTS materials may be used for the voltage taps 13a-13b and the voltage taps 14a-14b. In another example, the voltage taps 14a-14b may be made of copper wire as known in the art.

[0029] FIG. 1b shows a detail of an alternative embodiment to FIG. 1a, showing the electrical connection of the power taps 13a and 13b from the coil 12 with the power terminals of an external power supply circuit. For clarity, only the power tap 13b is shown as a short HTS tape component that exits the plane of the coil 12 at an angle α=90°. The HTS tape component (power tap) 13b (also its sub-tap 130b) extends with an additional HTS tape component 13b'. The additional HTS tape component 13b' acts as an extension of the power tap 13b (or sub-tap 130b). The additional HTS tape component 13b' is connected at its first end 13b'-a by a solder connection 13z to the HTS tape component 13b. The additional HTS tape component 13b' is electrically connected at its second end 13b'-b to the power terminals of the external power supply circuit (not shown).

[0030] Similarly (not shown), another power tap 13a in the form of an HTS tape component (and its sub-tap 130a) may extend with such additional HTS tape component 13a'. The additional HTS tape component 13a' acts as an extension of the power tap 13a (or sub-tap 130a). The additional HTS tape component 13a' is connected at its first end 13a'-a to the HTS tape component 13a by a solder connection 13z. The additional HTS tape component 13a' is electrically connected at its second end 13a'-b to a power terminal of another external power circuit (not shown).

[0031] Each of the tape-like power taps 13a and 13b (shown as additional HTS tape components 13b') is curved in the portion extending from the exit 13b'-a from the coil 12 to the connection point 13b'-b with the power terminals of the external power supply circuit (not shown). This curvature conforms to the magnetic field lines of the magnetic field generated by the coil assembly 10-10' during operation. This minimizes the disturbance and exposure to electromagnetic forces (Lorentz forces) caused by the exposure of the power taps 13a-13b to the magnetic field. Similarly, the first power tap 13a (and its sub-tap 130a) can extend with an additional HTS tape component 13a' (not shown). The additional HTS tape component 13a' is connected at its first end 13a'-a to the HTS tape component 13a by a solder connection 13z. The additional HTS tape component 13a' is electrically connected at its second end 13a'-b to a power terminal of an external power circuit (not shown).

[0032] It can be seen that both the first and second power taps 13a-13b (together with their sub-taps 130a-130b) can be formed directly as a stretched HTS tape component that leaves the face of the coil 12 and connects at its free end (corresponding to ends 13a'-b or 13b'-b of the tape component) to the power terminals of the external power supply circuit. In this embodiment, the solder connection 13z is not required.

[0033] As shown in FIGS. 1-3, the winding 12 is composed of two winding sections, which are respectively denoted by reference numerals 12a and 12b. To complete the coil, a plurality of turns are required, or it is assumed that the winding 12 is composed of N turns. And the first winding section 12a of the winding 12 is composed of M turns, and the second winding section 12b is composed of N−M turns. When composed of these two winding sections 12a and 12b, the first power tap 13a is electrically connected to the first turn closest to the core 11 of the winding 12. The second power tap 13b is electrically connected to the Mth turn of the winding 12. Again, note that M<N. The first and second power taps 13a-13b are respectively electrically connected to the positive and negative terminals of an external power source of the electromagnetic coil assembly 10-10' for supplying power to the coil 12.

[0034] Regarding the second winding section 12b, the first voltage tap 14a is electrically connected to the (M + 1)th turn of the second winding section 12b of the winding 12. And the second voltage tap 14b is electrically connected to the Oth turn of the winding 12. The Oth turn of the winding 12 is located on the outer periphery of the coil assembly. On the other hand, the first turn (turn 1) is located on the side of the core 11 of the coil assembly. Preferably, O≈N, and particularly O = N.

[0035] Regarding the comparison of the number of turns of each winding section 12a and 12b, the following holds. (N - M) / N << 1

[0036] In particular, 0.01 << (N - M) / N << 0.10 That is.

[0037] In any of the above equations, N is the total number of turns of the coil, and M is the number of turns between the first power tap 13a and the second power tap 13b.

[0038] In particular, the average winding of the multiple turns (i.e., turn 1 to turn M) of the first winding section 12a line The tension is the average winding force of the multiple turns of the second winding section 12b (i.e., from turn M+1 to turn N). line In particular, the M+1th turn to the Nth turn of the second winding section 12b has a higher average winding tension than the 1st turn to the Mth turn of the first winding section 12a. line When tensioned, the inner winding section, consisting of turns [1…M], is confined by the outer winding section, consisting of turns [M+1…N], which also increases the mechanical stability of the coil.

[0039] The use of two winding sections 12a and 12b of a coil assembly is known as "overbanding". However, in the electromagnetic coil assembly embodiments 10 and 10', the "overbanding" is formed by providing an additional winding section 12b that radially surrounds the first winding section 12a, i.e., the second winding section 12b surrounds the complete coil 12 to form a ring consisting of NM turns.

[0040] In one embodiment, the winding of the second winding section 12b is made of the same HTS tape winding as the first winding section 12a. In another embodiment, a different material is used, such as a metal tape of the same width as the HTS winding 12 forming the first winding section 12a. In this particular embodiment, the HTS tape winding is terminated at the second connection tap 13b after M turns. The HTS tape winding then continues to be wound NM turns with only the metal tape winding forming the second winding section 12b. By continuing to wind with a similarly shaped tape winding (the same HTS tape winding or a different metal tape winding) beyond the connection point of the second power tap 13b after M turns, it is possible to prevent the occurrence of free or loss ends in the winding section. If such free or loss ends of the winding section are present, they will be exposed to the generated magnetic field and may cause disturbances due to electromagnetic forces (Lorentz forces).

[0041] In another embodiment, the HTS tape winding continues from the first winding section 12a to the second winding section 12b.

[0042] As shown in Figures 2b-2c, the electromagnetic coil assembly 10' includes a third voltage tap 14c and a fourth voltage tap 14d. The third voltage tap 14c and the fourth voltage tap 14d are each connected to a turn of the coil in the first winding section 12a. As shown in Figure 2b, each of the third voltage tap 14c and the fourth voltage tap 14d may be electrically connected to the first power tap 13a and the second voltage tap 13b (at the first turn and the Mth turn of the first winding section 12a, respectively). Alternatively, as shown in Figure 2c, each of the third voltage tap 14c and the fourth voltage tap 14d may be electrically connected to a turn of the first winding section 12a.

[0043] Additionally, each of the third voltage tap 14c and the fourth voltage tap 14d are electrically connected to a quench voltage detection system 20 using conductors 20a-20b.

[0044] A quench voltage detection system 20 between the third voltage tap 14c and the fourth voltage tap 14d can be used to detect the quench voltage. However, the electromagnetic coil assembly according to the present invention may be realized by a non-contact actuating system. An actuator (carrier) passing through the electromagnetic coil assembly will disturb the magnetic field generated by the coil. Such an external disturbance or change in the magnetic field will induce a current in the turns / windings of the first winding section 12a. Unfortunately, this current can produce a false positive quench trigger.

[0045] The winding arrangement of the two winding sections 12a and 12b forms two concentric coils. With the additional windings from the M+1th turn to the Nth turn forming the second winding section 12b, when the coil assembly is powered from an external power source via the voltage taps 14a and 14b, zero voltage may be observed between the first and second voltage taps 14a and 14b, even if no external disturbances occur in the magnetic field. However, when an external disturbance occurs in the magnetic field (e.g., due to an actuator of a non-contact actuating system through the electromagnetic coil assembly), this external disturbance induces a current in the second winding section 12b. Then, the induced potential difference between the turn M+1 and the turn O(N) across the power taps 14a and 14b can be observed using an additional voltage detection system 21 connected to the first and second power taps 14a-14b using connecting conductors 21a-21b.

[0046] By implementing two further (third and fourth) voltage taps 14c-14d within the first winding section (e.g., by electrically connecting the third voltage tap 14c to the first power tap 13a and the fourth voltage tap 14d to the second power tap 13b by at least less than turn M), the quench voltage detection system 20 can be used to measure the potential difference between the third and fourth voltage taps 14c-14d, thereby effectively detecting a quench or loss of superconductivity that leads to a sudden increase in ohmic resistance within the winding section 12a.

[0047] However, the above-mentioned external disturbance of the magnetic field is also detected at the third and fourth voltage taps 14c-14d. Therefore, it is not possible to distinguish between a real quench in the first winding section 12a of the coil 12 and an external disturbance of the magnetic field by itself. In this case, by further implementing a quench voltage detection system 21 for the overbanding winding section 12b, any potential difference observed between the two voltage taps 14a-14b can be directly correlated to an external disturbance of the magnetic field. In this way, by performing potential difference measurements both between the two voltage taps 14c-14d and between the two voltage taps 14a-14b (more specifically, between the two winding sections 12a and 12b), the external effects can be counteracted, thus enabling a more reliable quench detection. [Explanation of symbols]

[0048] 10-10'...An embodiment of an electromagnetic coil assembly. 11 cores, 12 ··The windings that make up the coils formed as HTS tapes; 12a ·· A first group of turns [1;M], 12b A second group of turns [M+1;N], 13a··First power tap; 13b... second power tap; 13b' Additional HTS components / power tap extensions, 13z Solder connection, 14a first voltage tap; 14b second voltage tap; 14c Third voltage tap, 14d 4th voltage tap, 130a-130b ··Sub-tap of power tap, 140a-140b Sub-tap of voltage tap.

Claims

1. A core, a winding wound around the core a number of times to form a coil; a plurality of power taps for electrically connecting the windings to an external power circuit; the windings being formed as tape components comprising high temperature superconducting (HTS) material; the plurality of power taps are connected to the windings that exit the plane of the coil at a predetermined angle; the power tap has a curved portion extending from a position where it exits the coil to a position where it is connected to a power terminal of an external power supply circuit, 11. An electromagnetic coil assembly, comprising: a coil assembly including: a first end that is in contact with a first end of said coil;

2. 10. The electromagnetic coil assembly of claim 1, wherein said power tap is made of a superconducting material.

3. 3. The electromagnetic coil assembly of claim 2, wherein the power tap is formed as a tape power tap comprising high temperature superconducting (HTS) material.

4. 4. An electromagnetic coil assembly according to any one of claims 1 to 3, characterized in that the power taps are connected to the tape components at an angle α between 30° and 90°, in particular 90°.

5. The plurality of windings of the coil are composed of N turns, a first power tap connected to a first turn of the winding; a second power tap is connected to the Mth turn of the winding; 5. An electromagnetic coil assembly according to claim 1, wherein M<N.

6. a plurality of voltage taps for measuring voltage between at least a portion of the plurality of turns of the winding; a first voltage tap is connected to the (M+1)th turn of the winding; a second voltage tap is connected to the Oth turn of the winding; 6. An electromagnetic coil assembly according to claim 5, characterized in that O≈N, in particular O=N.

7. (NM) / N<1 7. The electromagnetic coil assembly according to claim 5, wherein:

8. 0.01<(NM) / N<0.10 8. The electromagnetic coil assembly according to claim 7, wherein:

9. A first turn to an Mth turn in the plurality of turns and an M+1th turn to an Nth turn in the plurality of turns are formed of windings of different materials, the Mth turn is terminated, 9. The electromagnetic coil assembly according to claim 1, wherein an average winding tension from the 1st turn to the Mth turn is lower than an average winding tension from the M+1th turn to the Nth turn.

10. 10. An electromagnetic coil assembly according to claim 1, wherein the core is a ferromagnetic core.

11. 11. An electromagnetic coil assembly as claimed in any preceding claim, wherein each of the power taps comprises a sub-tap.

12. 12. An electromagnetic coil assembly according to any one of claims 1 to 11, characterized in that the HTS material comprises at least one of the group consisting of (RE)BCO, BSCCO, TBCCO.

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