JPH08190848A - Permanent current switch - Google Patents
Permanent current switchInfo
- Publication number
- JPH08190848A JPH08190848A JP7000827A JP82795A JPH08190848A JP H08190848 A JPH08190848 A JP H08190848A JP 7000827 A JP7000827 A JP 7000827A JP 82795 A JP82795 A JP 82795A JP H08190848 A JPH08190848 A JP H08190848A
- Authority
- JP
- Japan
- Prior art keywords
- current switch
- superconducting
- permanent current
- current
- permanent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000002085 persistent effect Effects 0.000 claims description 28
- 238000004804 winding Methods 0.000 abstract description 8
- 230000001939 inductive effect Effects 0.000 abstract description 3
- 238000010791 quenching Methods 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 230000005284 excitation Effects 0.000 description 5
- 230000001965 increasing effect Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 230000000171 quenching effect Effects 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910017566 Cu-Mn Inorganic materials 0.000 description 1
- 229910002482 Cu–Ni Inorganic materials 0.000 description 1
- 229910017871 Cu—Mn Inorganic materials 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000005339 levitation Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000003507 refrigerant Substances 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
Landscapes
- Containers, Films, And Cooling For Superconductive Devices (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は超電導マグネットが永久
電流状態で使用される際に用いられる永久電流スイッチ
に関し、特に大電流用に用いられる永久電流スイッチに
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a persistent current switch used when a superconducting magnet is used in a persistent current state, and more particularly to a persistent current switch used for a large current.
【０００２】[0002]
【従来の技術】ＭＲＩや磁気浮上列車等に用いられる超
電導マグネットは、超電導線が巻かれた超電導コイルか
らなる。これを使用する場合、超電導マグネットに長期
間に渡り一定電流を流し続ける必要があるため、永久電
流スイッチ（ＰＣＳ）が使用される。永久電流スイッチ
としては超電導線の超電導状態と常伝導状態との遷移を
利用したものが広く利用されている。2. Description of the Related Art Superconducting magnets used in MRI, magnetic levitation trains, etc. consist of superconducting coils wound with superconducting wires. When this is used, a permanent current switch (PCS) is used because it is necessary to keep a constant current flowing through the superconducting magnet for a long period of time. As a persistent current switch, a switch utilizing a transition between a superconducting state and a normal conducting state of a superconducting wire is widely used.
【０００３】図２を参照しながら超電導マグネット装置
の運転動作について説明する。永久電流スイッチ４０と
超電導コイル５０とは励磁電源６０に対し並列に接続さ
れ、何れも冷媒容器内に収容されている。永久電流スイ
ッチ４０の開閉動作は、永久電流スイッチを構成する超
電導線が超電導状態になったときが閉じた状態（オン状
態）であり、一方、前記超電導線が常伝導状態のとき開
いた状態（オフ状態）になる。この常伝導状態のときの
抵抗は通常数〜数十オーム程度で、励磁電源６０から供
給される電流の殆どが超電導コイル５０に分流される。The operation of the superconducting magnet device will be described with reference to FIG. The permanent current switch 40 and the superconducting coil 50 are connected in parallel to the exciting power source 60, and both are housed in the refrigerant container. The opening / closing operation of the persistent current switch 40 is a closed state (ON state) when the superconducting wire forming the persistent current switch is in the superconducting state, and an open state (on state) when the superconducting wire is in the normal conducting state ( Turned off). The resistance in the normal conduction state is usually several tens to several tens of ohms, and most of the current supplied from the excitation power source 60 is shunted to the superconducting coil 50.
【０００４】この超電導マグネット装置を運転するとき
は、永久電流スイッチ４０が開いた状態で超電導コイル
５０に所定の電流を励磁電源６０によって供給（励磁）
した後、永久電流スイッチ４０を閉じれば、超電導コイ
ル５０と永久電流スイッチ４０とは超電導回路を形成し
て永久電流モードの周回電流が流れる仕組みになる。な
おこの周回電流を通例、永久電流モードと称している
が、実際には超電導コイル５０と永久電流スイッチ素子
４０との接続抵抗等が不可避的に存在するため、厳密に
は永久電流とはならない。When operating this superconducting magnet device, a predetermined current is supplied (excitation) to the superconducting coil 50 by the exciting power source 60 with the permanent current switch 40 open.
After that, when the persistent current switch 40 is closed, the superconducting coil 50 and the persistent current switch 40 form a superconducting circuit so that the circulating current in the persistent current mode flows. Although this circulating current is commonly referred to as a permanent current mode, in reality, the connection resistance between the superconducting coil 50 and the permanent current switch element 40 and the like are unavoidably present, so that strictly speaking, the permanent current is not generated.
【０００５】また永久電流スイッチ４０はその仕組み
上、常伝導転移したときはある程度高い電気抵抗値を有
することが必要である。これは永久電流スイッチ４０が
開いているとき、励磁電源６０から供給される電流の永
久電流スイッチ４０への分流を極力避けるためである。
このため永久電流スイッチを構成する超電導線として
は、Ｃｕ−Ｎｉ合金や、Ｃｕ−Ｍｎ合金といった比較的
高い電気抵抗値を有する金属をマトリックスとした超電
導線が一般に使用される。Due to its mechanism, the persistent current switch 40 needs to have a somewhat high electric resistance value when the normal conduction transition occurs. This is to avoid as much as possible a shunt of the current supplied from the excitation power supply 60 to the permanent current switch 40 when the permanent current switch 40 is open.
Therefore, as the superconducting wire that constitutes the permanent current switch, a superconducting wire using a metal having a relatively high electric resistance value such as a Cu—Ni alloy or a Cu—Mn alloy as a matrix is generally used.
【０００６】図３は永久電流スイッチの構造の一例を示
す説明図である。常伝導状態で比較的高い電気抵抗値を
有する超電導線を巻枠７１ａ、７１ｂに巻き、永久電流
スイッチ素子３ａ、３ｂを構成する。これらの永久電流
スイッチ素子３ａ、３ｂが口出し超電導線７４を介して
超電導コイルの端部７３に接続する。なお接続は接続部
７２で超電導接続されている。図３では、永久電流スイ
ッチ素子３ａ、３ｂが２個の場合を例示したが、この数
は任意である（もちろん１個でも構わない）。なお超電
導線を巻枠７１ａ、７１ｂに巻いてコイル７０ａ、７０
ｂにするのは、長さを延ばして常伝導状態のときの抵抗
を増大させるためである。また素子を複数個、並列接続
するのは電流容量を増やすためである。FIG. 3 is an explanatory view showing an example of the structure of the permanent current switch. A superconducting wire having a relatively high electric resistance value in a normal conduction state is wound around the winding frames 71a and 71b to form the permanent current switch elements 3a and 3b. These permanent current switch elements 3a and 3b are connected to the end portion 73 of the superconducting coil via a lead-out superconducting wire 74. The connection is superconducting connection at the connecting portion 72. Although FIG. 3 exemplifies the case where the number of the permanent current switch elements 3a and 3b is two, the number is arbitrary (it may be one, of course). The superconducting wire is wound around the bobbin 71a, 71b to form the coil 70a, 70b.
The reason for setting b is to extend the length and increase the resistance in the normal conduction state. A plurality of elements are connected in parallel in order to increase the current capacity.
【０００７】[0007]
【発明が解決しようとする課題】高磁場発生用超電導マ
グネットや中・大型超電導マグネット等の大電流で用い
られる超電導マグネットの場合、永久電流スイッチに大
電流が流れる。電流容量の小さい永久電流スイッチであ
るとクエンチしてしまう。そこで永久電流スイッチの電
流容量を増大する方法として永久電流スイッチを構成す
る超電導線を太径化する方法がある。また永久電流スイ
ッチ素子を多数個並列接続した永久電流スイッチを用い
たりする方法もある。In the case of a superconducting magnet used for a large current, such as a superconducting magnet for generating a high magnetic field or a medium / large-sized superconducting magnet, a large current flows through a permanent current switch. A permanent current switch with a small current capacity will be quenched. Therefore, as a method of increasing the current capacity of the persistent current switch, there is a method of increasing the diameter of the superconducting wire forming the persistent current switch. There is also a method of using a permanent current switch in which a large number of permanent current switch elements are connected in parallel.
【０００８】しかし永久電流スイッチを構成する超電導
線として、Ｃｕ−Ｎｉ合金／Ｎｂ−Ｔｉの丸線を使用す
る場合、現状では自己磁界不安定効果のため０．５ｍｍ
径（２００Ａ／Ｔの場合）程度が太径化の限界であり、
平角線にしても０．７ｍｍ×２ｍｍ程度（２００Ａ／Ｔ
の場合）が限界である。また太い超電導線を用いると図
３に示すように巻枠７１ａ、巻枠７１ｂ状に超電導線を
巻く都合上、剛性が高くなりすぎ巻線加工も難しくな
る。However, when a Cu--Ni alloy / Nb--Ti round wire is used as a superconducting wire which constitutes a permanent current switch, it is currently 0.5 mm due to the self-magnetic field instability effect.
The diameter (for 200 A / T) is the limit for increasing the diameter,
Even if it is a rectangular wire, it is about 0.7 mm x 2 mm (200 A / T
Is the limit. Further, if a thick superconducting wire is used, the rigidity becomes too high and winding processing becomes difficult due to the fact that the superconducting wire is wound around the winding frame 71a and the winding frame 71b as shown in FIG.
【０００９】そこで永久電流スイッチ素子を複数本並列
に接続した並列型の永久電流スイッチが大電流用途の場
合に広く採用されている。図３は２個並列型の例であ
る。並列型の永久電流スイッチは、各々の永久電流スイ
ッチ素子に電流が分流されるので、当然各々の素子に流
れる電流値は小さくなる。ところで運転すべき超電導マ
グネットに電流を流し始めた初期においては、各々の永
久電流スイッチに分流される電流値の時間微分値が大き
いため、各々の永久電流スイッチの抵抗値（接続抵抗
等）の影響が小さい。従って自己インダクタンスが均一
ならば運転すべき超電導マグネットに電流を流し始めた
初期においてほぼ一定の電流が分流されることになる
（相互インダクタンスの影響は自己インダクタンスの影
響に比べ小さい）。Therefore, a parallel type permanent current switch in which a plurality of permanent current switch elements are connected in parallel is widely used for large current applications. FIG. 3 shows an example of two parallel type. In the parallel type permanent current switch, since the current is shunted to each of the permanent current switch elements, the current value flowing in each element is naturally small. By the way, in the initial stage when the current starts to flow to the superconducting magnet to be operated, the time differential value of the current value shunted to each permanent current switch is large, so the influence of the resistance value (connection resistance etc.) of each permanent current switch Is small. Therefore, if the self-inductance is uniform, a substantially constant current will be shunted at the beginning of the flow of current to the superconducting magnet to be operated (the effect of mutual inductance is smaller than the effect of self-inductance).
【００１０】そして電流供給の初期を経て、定常電流状
態に近づくにつれ、自己インダクタンスの影響が少なく
なり（完全な定常電流であれば、時間微分が零にな
る）、各々の永久電流スイッチ素子に分流される電流値
が接続抵抗によってほぼ規定される。従って定常電流に
おいては、各々の永久電流スイッチ素子の接続抵抗が一
定ならば一定の電流が分流されることになる。具体的に
は例えば同じ抵抗値の永久電流スイッチ素子を２個並列
接続した永久電流スイッチの場合、１／２ずつ分流され
ることになる。しかしながら実際には、各々の永久電流
スイッチ素子の接続抵抗を一定にすることは極めて困難
である。なぜなら超電導回路の場合のように極めて微小
オーダーの電気抵抗が問題となる場合、その程度の微小
オーダー（通常１０-12 オーム以下のオーダーである）
の接続抵抗は接続する超電導線同士の密着の度合いや密
着させる表面の表面状態によって極めて大きく影響され
るからである。実用的には、数倍程度の接続抵抗の差を
避けるのは難しい。従ってある永久電流スイッチ素子と
他のそれとに分流される電流値に数倍程度の差が生じる
ことは少なくない。そして多くの場合、一つの永久電流
スイッチ素子に容量以上の分流がなされクエンチすると
永久電流スイッチ全体がクエンチしてしまうのである。After the initial supply of current, the effect of self-inductance decreases as the steady current state is approached (the time derivative becomes zero for a complete steady current), and the current is shunted to each permanent current switch element. The current value to be applied is almost specified by the connection resistance. Therefore, in the steady current, if the connection resistance of each permanent current switch element is constant, a constant current will be shunted. Specifically, for example, in the case of a permanent current switch in which two permanent current switch elements having the same resistance value are connected in parallel, the current is divided by 1/2. However, in practice, it is extremely difficult to make the connection resistance of each permanent current switch element constant. Because when the electric resistance of an extremely small order is a problem, as in the case of a superconducting circuit, such a small order (usually 10 -12 ohms or less)
This is because the connection resistance of 1 is greatly influenced by the degree of close contact between the superconducting wires to be connected and the surface condition of the surfaces to be brought into close contact with each other. Practically, it is difficult to avoid a difference in connection resistance of several times. Therefore, it is not uncommon for the current value split between a certain persistent current switch element and another to be several times different. In many cases, if a single shunt current element is shunted by a shunt exceeding its capacity, the entire quiescent current switch is quenched.
【００１１】ところで電流容量を大きくしてクエンチし
にくい安定した永久電流スイッチを得るには、単純には
並列接続する永久電流スイッチ素子の数を増やせばよ
い。しかしいたずらにその数を増やしても永久電流スイ
ッチのサイズが大型化したり、コストが上昇する等、好
ましくない。By the way, in order to increase the current capacity and obtain a stable permanent current switch which is hard to be quenched, simply increase the number of permanent current switch elements connected in parallel. However, even if the number is increased unnecessarily, the size of the permanent current switch becomes large and the cost rises, which is not preferable.
【００１２】[0012]
【課題を解決するための手段】本発明は上述の事情に鑑
みてなされたもので、クエンチしにくい安定した永久電
流スイッチを提供しようとするものである。即ち本発明
は、４本の超電導線がソレノイド状に卷回されてなり、
当該超電導線の極性が交互かつ対称的になるように４本
の前記超電導線が無誘導に並列接続された永久電流スイ
ッチ素子により構成される永久電流スイッチである。ま
た前記永久電流スイッチ素子を複数個並列接続してなる
永久電流スイッチを提供する。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a stable persistent current switch which is hard to quench. That is, according to the present invention, four superconducting wires are wound in a solenoid shape,
It is a permanent current switch composed of a permanent current switch element in which four superconducting wires are connected in parallel in a non-inductive manner so that the polarities of the superconducting wires are alternate and symmetrical. Also provided is a permanent current switch comprising a plurality of the above-mentioned persistent current switch elements connected in parallel.
【００１３】[0013]
【作用】本発明は、種々の検討を行った結果なされたも
ので、特に大電流容量用の用途に好適に適用できる永久
電流スイッチである。本発明では永久電流スイッチ素子
を４本の超電導線をソレノイド状に卷回することで形成
している。こうして形成された永久電流スイッチ素子
は、４本の超電導線が４本並列巻きされた構造になって
いるが、これらの超電導線の接続に際し、図１に示すよ
うに、超電導線１０の接続を、各々の極性が交互に対称
的になるように接続する。そしてこの永久電流スイッチ
素子３は全体として無誘導巻きになっている。The present invention has been made as a result of various investigations, and is a permanent current switch which can be suitably applied to a large current capacity application. In the present invention, the permanent current switch element is formed by winding four superconducting wires in a solenoid shape. The permanent current switch element thus formed has a structure in which four superconducting wires are wound in parallel. When connecting these superconducting wires, the superconducting wires 10 are connected as shown in FIG. , And connect so that their polarities are alternately symmetrical. The permanent current switch element 3 is inductively wound as a whole.
【００１４】本発明では、４本の超電導線が４本並列巻
きされた構造の永久電流スイッチを採用するのは以下の
理由による。図４は、一例として６本の超電導線が並列
巻きされた構造の永久電流スイッチ素子により構成され
る永久電流スイッチの等価回路を示すものである。図４
では、簡明を期するために永久電流スイッチ素子を１個
としている。超電導線１１、１２、１３と超電導線１
４、１５、１６の極性が逆になるように接続され、コイ
ルの巻き方向が逆になっている。これらの各々に流れる
電流値は各々Ｉ1 、Ｉ2 、Ｉ3 、Ｉ4 、Ｉ5 、Ｉ6 とす
る。そしてこれらの超電導線の接続抵抗をＲ1 、Ｒ2 、
Ｒ3 、Ｒ4 、Ｒ5 、Ｒ6 とし、また各々の自己インダク
タンスは殆ど同等なのでここではこれらをＬとする。ま
た各超電導線間の相互インダクタンスは位置関係等によ
って多少異なるが、超電導コイル５１に電流を励磁する
初期を経て、ほぼ永久電流モードの周回電流が流れてい
る状態では、各々の相互インダクタンスはほぼ同等とし
ても大きな影響はない。そこで各超電導線間の相互イン
ダクタンスを全てＭとする。図４の等価回路の回路方程
式を以下に示す。In the present invention, the reason why the permanent current switch having the structure in which four superconducting wires are wound in parallel with each other is adopted is as follows. FIG. 4 shows, as an example, an equivalent circuit of a permanent current switch configured by a permanent current switch element having a structure in which six superconducting wires are wound in parallel. FIG.
Then, for the sake of simplicity, one permanent current switch element is used. Superconducting wires 11, 12, 13 and superconducting wire 1
The polarities of 4, 15, and 16 are connected in reverse, and the winding directions of the coils are reversed. The current values flowing in each of these are assumed to be I 1 , I 2 , I 3 , I 4 , I 5 , and I 6 , respectively. The connection resistances of these superconducting wires are R 1 , R 2 ,
R 3, and R 4, R 5, R 6 , also each of the self-inductance them to L here because almost equivalent. Although the mutual inductance between the superconducting wires is slightly different depending on the positional relationship and the like, after the initial stage of exciting the current in the superconducting coil 51, the mutual inductances are almost the same in the state where the circulating current in the almost permanent current mode flows. However, there is no big impact. Therefore, the mutual inductance between the respective superconducting wires is M. The circuit equation of the equivalent circuit of FIG. 4 is shown below.
【００１５】[0015]
【数１】 [Equation 1]
【００１６】さてここでＲ1 ＝Ｒ2 ＝３×１０-11 オー
ム、Ｒ3 ＝Ｒ4 ＝Ｒ5 ＝Ｒ6 ＝３×１０-13 オームとし
てこの回路方程式（連立微分方程式）を数値計算して解
くと図５のようになる。なお接続抵抗による電流減衰は
ないものとして計算している。曲線（Ｉ１）および曲線
（Ｉ２）は超電導線１１または超電導線１２に流れる電
流値Ｉ1 、Ｉ2 の時間遍歴を示し、曲線（Ｉ３）は超電
導線１３に流れる電流値Ｉ3 の遍歴を示す。超電導コイ
ル５１に通電する初期において超電導線１１、１２、１
３に流れていた電流値Ｉ1(t ＝0 ) 、Ｉ2(t ＝0 ) 、Ｉ
3(t ＝0 ) を７０Ａ（この時点では上記超電導線に流
れる電流値はほぼ等しい。自己インダクタンスおよび相
互インダクタンスが等しく、各々の接続抵抗値の相違の
影響が少ないからである）とすると、この数値計算結果
により、ほぼ１年間経過する頃ではＩ3(t ＝１年) が２
００Ａに近くなり、Ｉ1(t ＝１年）とＩ2(t ＝１年) が
１０Ａ以下になることが判る。Now, the circuit equations (simultaneous differential equations) are numerically calculated with R 1 = R 2 = 3 × 10 -11 ohms and R 3 = R 4 = R 5 = R 6 = 3 × 10 -13 ohms. The solution is as shown in Fig. 5. It is assumed that there is no current attenuation due to connection resistance. The curve (I1) and the curve (I2) show the time history of the current values I 1 and I 2 flowing through the superconducting wire 11 or the superconducting wire 12, and the curve (I3) shows the history of the current value I 3 flowing through the superconducting wire 13. . The superconducting wires 11, 12, 1 are initially supplied to the superconducting coil 51.
Current values I 1 (t = 0), I 2 (t = 0), I
If 3 (t = 0) is set to 70 A (current values flowing in the superconducting wire at this point are almost equal, self-inductance and mutual inductance are equal, and the influence of the difference in connection resistance values is small). According to the numerical calculation results, I 3 (t = 1 year) is 2 when almost one year has passed.
It is close to 00A, and I 1 (t = 1 year) and I 2 (t = 1 year) are 10A or less.
【００１７】また超電導線１４、１５、１６に流れる電
流値Ｉ4 、Ｉ5 、Ｉ6 は曲線（１４）、曲線（Ｉ５）、
曲線（Ｉ６）のように時間変動する。つまり超電導コイ
ル５１に通電する初期において流れていた電流値（７０
Ａ）のままである。これはこれらの超電導線の接続抵抗
値が等しいと仮定したからである。以上の結果より、超
電導線１１、１２に流れていた電流分が超電導線１３に
再配分されたことが判る。超電導線１４、１５、１６に
流れていた電流が超電導線１３に分流しなかったのは磁
気的カップリングのためである。The current values I 4 , I 5 , I 6 flowing through the superconducting wires 14, 15, 16 are the curve (14), the curve (I5),
It changes with time as shown by the curve (I6). That is, the current value (70
It remains A). This is because it is assumed that the connection resistance values of these superconducting wires are equal. From the above results, it can be seen that the amount of current flowing through the superconducting wires 11 and 12 was redistributed to the superconducting wire 13. The current flowing through the superconducting wires 14, 15 and 16 was not shunted into the superconducting wire 13 because of magnetic coupling.
【００１８】ここで超電導コイル５１に通電する初期に
おける超電導線に流れる電流値を定格電流値Ｉopとし、
各々の超電導線の臨界電流値Ｉc との比γ＝Ｉop／Ｉc
を考える。図５では４００日までの時間経過しか示して
いないが、更に長期間が経過すると最終的には曲線（Ｉ
１、Ｉ２）が０に近づき、その電流値の減少分が曲線
（Ｉ３）に再配分されることになる。つまり接続抵抗に
よる電流減衰を無視すれば曲線（Ｉ３）は最終的にはＩ
1(t ＝0)×３程度まで上昇することになる。従ってこの
場合γは１／３より小さいことが必要になる。Here, the current value flowing through the superconducting wire in the initial stage of energizing the superconducting coil 51 is defined as the rated current value I op ,
Ratio of critical current value I c of each superconducting wire γ = I op / I c
think of. In FIG. 5, only the time elapses up to 400 days is shown, but after a further longer time, the curve (I
1, I2) approaches 0, and the decrease in the current value is redistributed to the curve (I3). In other words, if the current attenuation due to the connection resistance is ignored, the curve (I3) will eventually become I
It will rise to about 1 (t = 0) × 3. Therefore, in this case, γ needs to be smaller than 1/3.
【００１９】上述の例は、抵抗Ｒ1 ＝Ｒ2 ≫Ｒ3 と仮定
した場合であるから、超電導線１３に最大限に再配分さ
れる例である。しかしクエンチが起きにくい永久電流ス
イッチを得るには、γを１／３より小さくしておくこと
が望ましい。この例は超電導線が６本の場合であるが、
２本、４本、８本の場合も同様に解析した。これらの結
果をまとめると、各々の定格電流値／臨界電流値の値
が、γ2 ＝１／２、γ4＝１／２、γ6 ＝１／３、γ8
＝１／４であることが望ましいことが判った。つまり超
電導線の本数が増える程、各々の超電導線の臨界電流値
を大きくする必要が生じている。臨界電流値の高い超電
導線を得るにはそれだけコストが高くなるから、効率的
には超電導線が４本の場合が最適であることが判る。The above-mentioned example is a case where the resistance R 1 = R 2 >> R 3 is assumed, so that the superconducting wire 13 is redistributed to the maximum extent. However, in order to obtain a permanent current switch in which quenching does not easily occur, it is desirable to make γ smaller than 1/3. In this example, there are 6 superconducting wires,
The same analysis was performed in the case of 2, 4, and 8. Summarizing these results, the values of the rated current value / critical current value are γ 2 = 1/2, γ 4 = 1/2, γ 6 = 1/3, γ 8
It was found that = 1/4 is desirable. That is, as the number of superconducting wires increases, it becomes necessary to increase the critical current value of each superconducting wire. Since the cost increases to obtain a superconducting wire having a high critical current value, it can be understood that the case of four superconducting wires is optimal in terms of efficiency.
【００２０】以上が本発明において４本の超電導線を用
いて卷回し、これらの超電導線を極性が交互かつ対称的
になるように無誘導に並列接続した永久電流スイッチ素
子を用いる理由である。上記永久電流スイッチ素子を必
要に応じて並列に接続すれば、永久電流スイッチ全体の
電流容量を高めることが可能である。この場合、各々の
永久電流スイッチ素子間の電流の再分配は殆ど生じな
い。これは各々の永久電流スイッチ素子は各々別コイル
を形成しており、相互の磁気的干渉は少ないからであ
る。The above is the reason why the present invention uses the permanent current switch element in which four superconducting wires are wound and the superconducting wires are non-inductively connected in parallel so that the polarities are alternately and symmetrically. If the permanent current switch elements are connected in parallel as necessary, the current capacity of the entire permanent current switch can be increased. In this case, redistribution of current between the respective permanent current switch elements hardly occurs. This is because each of the persistent current switch elements forms a different coil, and mutual magnetic interference is small.
【００２１】なお、４本の超電導線をソレノイド状に卷
回する際、予め４本撚りの超電導撚線を用いると望まし
い。この場合、卷回するとき超電導線がばらけにくくな
り巻きやすくなる。また超電導コイルによる外部磁界の
影響を低減でき、更に超電導撚線に掛かる（超電導コイ
ルおよび永久電流スイッチによる）電磁力がほぼつり合
うという利点もある。When the four superconducting wires are wound in the form of a solenoid, it is desirable to use a superconducting twisted wire having four twists in advance. In this case, the superconducting wire is less likely to come loose when it is wound, making it easier to wind. Further, there is an advantage that the influence of the external magnetic field due to the superconducting coil can be reduced and the electromagnetic force (due to the superconducting coil and the permanent current switch) applied to the superconducting stranded wire is almost balanced.
【００２２】[0022]
【実施例】次に実施例および比較例を説明する。 実施例１ 直径０．４ｍｍの超電導線を用いて４本撚りの超電導撚
線を形成した。ピッチは約２０ｍｍである。これを図１
に示すように巻枠２０（直径２０ｍｍの円筒形状）に１
００ターン（約５０ｍ使用）した。各超電導線１０の自
己インダクタンスはほぼ同等で、全て０．１５ｍＨ程度
である。そして図１に示す如く、各超電導線１０の極性
が交互に対称的になるように接続した。接続に際しては
超電導線の超電導フィランメントを露出させ、露出した
超電導フィラメント同士を接触させた上、半田付けす
る、いわゆる超電導接続を行った。こうして永久電流ス
イッチを形成した。各々接続抵抗の平均値は１×１０
-12 オーム以下である。なお接続抵抗のバラツキが極力
小さくなるように努力したが、不可避的に数倍程度のバ
ラツキの発生は避けにくい。EXAMPLES Next, examples and comparative examples will be described. Example 1 A superconducting stranded wire having four strands was formed using a superconducting wire having a diameter of 0.4 mm. The pitch is about 20 mm. Figure 1
1 on the reel 20 (cylindrical shape with a diameter of 20 mm) as shown in
I made 00 turns (using about 50 m). The self-inductances of the respective superconducting wires 10 are almost the same and are all about 0.15 mH. Then, as shown in FIG. 1, the superconducting wires 10 were connected so that the polarities thereof were alternately symmetrical. At the time of connection, so-called superconducting connection was performed in which the superconducting filament of the superconducting wire was exposed, and the exposed superconducting filaments were brought into contact with each other and then soldered. Thus, a permanent current switch was formed. The average value of each connection resistance is 1 x 10
-12 ohms or less. Although efforts have been made to minimize variations in connection resistance, it is unavoidable that variations of several times will occur.
【００２３】本実施例では永久電流スイッチ素子３０を
１個用いて永久電流スイッチを構成した。テストのため
にこの永久電流スイッチを数個用意して、これを１Ｔの
印加磁場中でクエンチ試験を行った結果、クエンチ電流
ＩQ （実施例１）は何れも約４５０Ａ程度であった。ま
た自己インダクタンスが１Ｈの超電導コイルにこの永久
電流スイッチを接続して３００Ａの永久電流モードでの
通電試験を行ったところ、１年を経ても何れの永久電流
スイッチにもクエンチが発生しなかった。In this embodiment, one permanent current switch element 30 is used to form a permanent current switch. The persistent current switch with several ready for testing, the results of which were quenched tested in an applied magnetic field of 1T, quench current I Q (Example 1) was both approximately 450A. Further, when this permanent current switch was connected to a superconducting coil having a self-inductance of 1H and an energization test was conducted in a 300 A permanent current mode, no quench occurred in any of the persistent current switches even after one year.
【００２４】実施例２ 実施例２では、図３に示すように実施例１と同様の永久
電流スイッチ素子を用いて、これを２個並列に接続して
並列型の永久電流スイッチを形成した。この永久電流ス
イッチを数個用意して、これを１Ｔの印加磁場中でクエ
ンチ試験を行った結果、クエンチ電流ＩQ （実施例２）
は何れも約９００Ａであった。これは実施例１の約２倍
に相当する。また自己インダクタンスが１Ｈの超電導コ
イルにこの永久電流スイッチを接続して６００Ａの永久
電流モードでの通電試験を行ったところ、何れも１年の
期間を経ても永久電流スイッチにクエンチが発生しなか
った。Example 2 In Example 2, as shown in FIG. 3, two permanent current switch elements similar to those of Example 1 were used and two of them were connected in parallel to form a parallel type permanent current switch. Several permanent current switches were prepared and subjected to a quench test in an applied magnetic field of 1 T. As a result, a quench current IQ (Example 2)
Was about 900 A in each case. This corresponds to about twice that of Example 1. Also, when this permanent current switch was connected to a superconducting coil having a self-inductance of 1H and a current test was conducted in a persistent current mode of 600A, no quench occurred in the persistent current switch even after a period of one year. .
【００２５】比較例１ 実施例１、２で用いた超電導線と同様のものを用い、こ
れを６本、および同寸法の純銅線１本を用いて７本撚り
の超電導撚線を形成した。これを直径２０ｍｍの円筒形
状の巻枠に巻いて（１００ターン、約５０ｍ使用）永久
電流スイッチ素子を組み立てた。各超電導線の自己イン
ダクタンスはほぼ０．１５ｍＨであった。そして実施例
１と同様にして各超電導線の極性が交互に対称的になる
ように接続した。各々接続抵抗の平均値は１×１０-12
オーム以下である。なお接続抵抗のバラツキは極力小さ
くなるように努力したが、不可避的に数倍程度のバラツ
キは避けにくいことは実施例１と同様である。この永久
電流スイッチ素子を１個用いて永久電流スイッチを構成
した。Comparative Example 1 A superconducting stranded wire having 7 strands was formed by using the same superconducting wire as used in Examples 1 and 2, and using 6 of this and 1 pure copper wire of the same size. This was wound on a cylindrical winding frame having a diameter of 20 mm (100 turns, using about 50 m) to assemble a permanent current switch element. The self-inductance of each superconducting wire was approximately 0.15 mH. Then, in the same manner as in Example 1, the superconducting wires were connected so that the polarities thereof were alternately symmetrical. The average value of each connection resistance is 1 × 10 -12
It is less than or equal to ohms. Although efforts have been made to minimize variations in connection resistance, it is inevitable that variations of several times are unavoidable, as in the first embodiment. A permanent current switch was constructed using one of the permanent current switch elements.
【００２６】この永久電流スイッチを数個用意して、こ
れを１Ｔの印加磁場中でクエンチ試験を行った結果、ク
エンチ電流ＩQ （比較例１）は何れも約６００〜７００
Ａであった。この値は、実施例１の約３／２倍程度であ
る。また自己インダクタンスが０．５Ｈの超電導コイル
に永久電流スイッチを接続して４００Ａの永久電流モー
ドでの通電試験を行ったところ、１〜３月程度でクエン
チが発生した。[0026] In this persistent current switch several prepared, results which were quenched tested in an applied magnetic field of 1T, quench current I Q (Comparative Example 1) Any of about 600-700
It was A. This value is about 3/2 times that of the first embodiment. Further, a permanent current switch was connected to a superconducting coil having a self-inductance of 0.5H, and an energization test was conducted in a persistent current mode of 400 A. A quench occurred in about 1 to 3 months.
【００２７】クエンチ試験におけるクエンチ電流は、ほ
ぼ超電導線の本数に比例して大きくなるので、比較例１
は実施例１に比べクエンチ電流が約３／２倍になってい
る。しかし永久電流モードでの通電試験においては、実
施例１や２に比べ短期間にクエンチが発生してしまっ
た。このため比較例１の永久電流スイッチは実施例１、
２に比べ長期間の運転に際し安定性の高いものではなか
った。比較例１の場合を実施例１、２の場合と同様、長
期間安定性を高めるには、永久電流モードでの運転に際
して通電電流を下げる必要がある。Since the quench current in the quench test increases in proportion to the number of superconducting wires, Comparative Example 1
The quench current is about 3/2 times that of the first embodiment. However, in the energization test in the permanent current mode, quenching occurred in a short period of time as compared with Examples 1 and 2. Therefore, the permanent current switch of Comparative Example 1 is the same as that of Example 1,
Compared to No. 2, the stability was not high during long-term operation. In the case of Comparative Example 1, as in the case of Examples 1 and 2, in order to enhance long-term stability, it is necessary to reduce the energization current during operation in the permanent current mode.
【００２８】以上の結果から、例えば超電導線１２本分
の電流容量の永久電流スイッチを組み立てるには、比較
例１における永久電流スイッチ素子を２個並列接続する
より、実施例１における永久電流スイッチ素子を３個並
列接続して組み立てた方が効率的であることが判る。つ
まり本発明の永久電流スイッチは性能的にもコスト的に
も効率的なものなのである。From the above results, for example, in order to assemble a permanent current switch having a current capacity of 12 superconducting wires, two permanent current switch elements in Comparative Example 1 are connected in parallel, and a permanent current switch element in Example 1 is used. It can be seen that it is more efficient to assemble three by connecting in parallel. That is, the persistent current switch of the present invention is efficient in terms of performance and cost.
【００２９】[0029]
【効果】以上説明したように本発明の永久電流スイッチ
は、効率的に永久電流モードでの運転においてクエンチ
が抑制されたもので、産業上の貢献は著しいものであ
る。As described above, the permanent current switch of the present invention effectively suppresses quenching during operation in the persistent current mode, and makes a significant industrial contribution.
【図１】本発明の永久電流スイッチを構成する永久電流
スイッチ素子を示す説明図である。FIG. 1 is an explanatory diagram showing a permanent current switch element that constitutes a permanent current switch of the present invention.
【図２】永久電流スイッチと超電導マグネットを用いた
回路図である。FIG. 2 is a circuit diagram using a permanent current switch and a superconducting magnet.
【図３】本発明の永久電流スイッチを示す説明図であ
る。FIG. 3 is an explanatory diagram showing a persistent current switch of the present invention.
【図４】６本の超電導線が並列巻きされた構造の永久電
流スイッチ素子により構成される永久電流スイッチの等
価回路を示す回路図である。FIG. 4 is a circuit diagram showing an equivalent circuit of a permanent current switch configured by a permanent current switch element having a structure in which six superconducting wires are wound in parallel.
【図５】図４の等価回路の回路方程式を数値解析した結
果を示す。5 shows the result of numerical analysis of the circuit equation of the equivalent circuit of FIG.
１０ 超電導線 ２０ 巻枠 ３０ 永久電流スイッチ素子 ４０ 永久電流スイッチ ５０ 超電導コイル ６０ 励磁電源 ３ａ、３ｂ 永久電流スイッチ素子 ７０ａ、７０ｂ コイル ７１ａ、７１ｂ 巻枠 ７２ 半田接続部 ７３ 端部 ７４ 口出し超電導線 １１、１２、１３、１４、１５、１６ 超電導線 ５１ 超電導コイル ６１ 励磁電源 10 superconducting wire 20 reel 30 permanent current switch element 40 permanent current switch 50 superconducting coil 60 excitation power source 3a, 3b permanent current switch element 70a, 70b coil 71a, 71b reel 72 solder connection portion 73 end portion 74 lead superconducting wire 11, 12, 13, 14, 15, 16 Superconducting wire 51 Superconducting coil 61 Excitation power supply
Claims (2)
れてなり、当該超電導線の極性が交互かつ対称的になる
ように４本の前記超電導線が無誘導に並列接続された永
久電流スイッチ素子により構成される永久電流スイッ
チ。1. A permanent current in which four superconducting wires are wound in a solenoid shape, and the four superconducting wires are non-inductively connected in parallel so that the polarities of the superconducting wires are alternate and symmetrical. Persistent current switch composed of switch elements.
複数個並列接続されてなる永久電流スイッチ。2. A persistent current switch comprising a plurality of the persistent current switch elements according to claim 1 connected in parallel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7000827A JPH08190848A (en) | 1995-01-06 | 1995-01-06 | Permanent current switch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7000827A JPH08190848A (en) | 1995-01-06 | 1995-01-06 | Permanent current switch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08190848A true JPH08190848A (en) | 1996-07-23 |
Family
ID=11484481
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7000827A Pending JPH08190848A (en) | 1995-01-06 | 1995-01-06 | Permanent current switch |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08190848A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19720397A1 (en) * | 1997-05-15 | 1999-04-01 | Magnet Motor Gmbh | Superconducting high current switch |
-
1995
- 1995-01-06 JP JP7000827A patent/JPH08190848A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19720397A1 (en) * | 1997-05-15 | 1999-04-01 | Magnet Motor Gmbh | Superconducting high current switch |
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