JPH01217902A - Persistent current switch - Google Patents
Persistent current switchInfo
- Publication number
- JPH01217902A JPH01217902A JP63042188A JP4218888A JPH01217902A JP H01217902 A JPH01217902 A JP H01217902A JP 63042188 A JP63042188 A JP 63042188A JP 4218888 A JP4218888 A JP 4218888A JP H01217902 A JPH01217902 A JP H01217902A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- superconductor
- winding
- current
- switch
- 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 title claims abstract description 14
- 239000002887 superconductor Substances 0.000 claims abstract description 53
- 238000004804 winding Methods 0.000 claims abstract description 33
- 239000000919 ceramic Substances 0.000 claims abstract description 31
- 239000007788 liquid Substances 0.000 abstract description 11
- 230000007613 environmental effect Effects 0.000 abstract description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract description 8
- 239000001307 helium Substances 0.000 abstract description 7
- 229910052734 helium Inorganic materials 0.000 abstract description 7
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 abstract description 7
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 4
- 230000002238 attenuated effect Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 10
- 230000005284 excitation Effects 0.000 description 6
- 239000000956 alloy Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000004020 conductor Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
Landscapes
- Containers, Films, And Cooling For Superconductive Devices (AREA)
- Electronic Switches (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
この発明は、ＭＲＩ用超電導マグネット等に用いられる
永久電流スイッチに関し、特に寒剤を消費せずに短時間
で動作可能な永久電流スイッチに関するものである。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a persistent current switch used in superconducting magnets for MRI, etc., and particularly relates to a persistent current switch that can operate in a short time without consuming cryogen. be.
［従来の技術］
第７図は従来の永久電流スイッチを含む超電導マグネッ
ト装置を示す回路図である。[Prior Art] FIG. 7 is a circuit diagram showing a superconducting magnet device including a conventional persistent current switch.
図において、（１）は超電導マグネットとなる超電導巻
線であり、２点ＡＢ間の超電導体（１ａ）と共に、例え
ばＮｂＴｉ等の合金系超電導体により形成されている。In the figure, (1) is a superconducting winding that becomes a superconducting magnet, and is made of an alloy-based superconductor such as NbTi, for example, together with the superconductor (1a) between two points AB.
（２）は２点ＡＢを介して超電導体（１ａ）と共に超電
溝巻ａ（１）に接続された励磁回路であり、励磁用電源
（２１）と、これに直列接続された開閉スイッチ（２２
）とから構成されている。(2) is an excitation circuit connected to the superconductor (1a) and the superconductor groove winding a (1) via two points AB, and includes an excitation power source (21) and an on/off switch ( 22
).
（３）は永久電流スイッチとなるヒータ回路であり、ヒ
ータ用電源（３１）と、これに直列接続された開閉スイ
ッチ（３２）と、超電導体（１ａ）に近接して設けられ
且つ開閉スイッチ（３２）により選択的に通電されるヒ
ータ（３３）とから構成されている。(3) is a heater circuit that serves as a persistent current switch, and includes a heater power source (31), an on/off switch (32) connected in series with the heater circuit, and an on/off switch (32) that is provided close to the superconductor (1a). 32), and a heater (33) that is selectively energized by the heater (32).
（４）は超電導巻線（１）及び超電導体（１ａ）を極低
温状態に保つためのクライオスタット、（５）はクライ
オスタット（４）内に真空層を介して設けられ且つヒー
タ（３３）と共に超電導巻線（１）及び超電導体（１ａ
）を収納した液体ヘリウム槽である。(4) is a cryostat for keeping the superconducting winding (1) and the superconductor (1a) at an extremely low temperature, and (5) is a superconductor that is installed in the cryostat (4) via a vacuum layer and together with the heater (33). Winding (1) and superconductor (1a
) is a liquid helium tank containing
第８図及び第９図は第７図内の２点鎖線内を詳細に示す
縦断面図及び横断面図であり、（３４）はヒータ（３３
）及び超電導体（１ａ）が同心的に巻回される支持巻枠
である。ヒータ（３３）及び超電導体（１ａ）はインダ
クタンス成分を持たないようにランダムに巻回され、両
者の間には絶縁物〈図示せず）が介在されている。8 and 9 are a vertical cross-sectional view and a cross-sectional view showing details of the area within the two-dot chain line in FIG. 7, and (34) is a heater (33).
) and the superconductor (1a) are wound concentrically. The heater (33) and the superconductor (1a) are randomly wound so as not to have an inductance component, and an insulator (not shown) is interposed between them.
次に、第１０１Ａ〜第１２図の回路図を参照【、なから
、第７図〜第９図に示した従来の永久電流スイッチの動
作について説明する。Next, referring to the circuit diagrams in FIGS. 101A to 12, the operation of the conventional persistent current switch shown in FIGS. 7 to 9 will be described.
通常は、第７図のように開田スイッチ（２２）及び（３
２）が開放されており、超電導巻線〈１）及び超電導体
〈１ａ）は液体ヘリウム槽（５）Ｃより４°に程度に冷
却されて超電導状態にある。Normally, Kaida switches (22) and (3) are used as shown in Figure 7.
2) is open, and the superconducting winding <1) and the superconductor <1a) are cooled to about 4° by the liquid helium tank (5) C and are in a superconducting state.
超電導巻線（１）を励磁するＰ４合は１．′＆ず、第１
０図のようにヒータ回路（３）内の開閉スイッチ（３２
）を閑成し、ヒータ用電源（３１）からヒータク３３）
に電流Ｉ Ｈを供給する。通電されたヒータ（３３）は
、発熱して超電導体く１ａ）を加熱し、超電導体（１ａ
）の臨界温度以上にする５この温度上昇により、超電導
体（１３）は超電導状態から常電導状態となり、抵抗器
と１−で作用するようになる。The P4 case that excites the superconducting winding (1) is 1. '&zu, 1st
As shown in figure 0, open/close switch (32) in heater circuit (3).
) and then connect the heater power supply (31) to the heater (33).
A current IH is supplied to. The energized heater (33) generates heat and heats the superconductor (1a).
) 5 Due to this temperature rise, the superconductor (13) changes from a superconducting state to a normal conducting state, and comes to act in a 1- manner with the resistor.
この状態Ｃ１第１１図のように励磁回路〈２）内の開閉
ス・イッチ（２２）を閉成し、励磁用電源〈２１）から
電流ＩＮを供給すると、超電導体（１ａ）が抵１抗を持
つているため、電流ＩＮは全て超電導８線（１）６：流
れる。In this state C1, as shown in Fig. 11, when the on/off switch (22) in the excitation circuit (2) is closed and current IN is supplied from the excitation power source (21), the superconductor (1a) Therefore, the current IN flows through all the 8 superconducting wires (1) 6:.
続いて、第１２図のように開閉スイ・・ｌチ（３２）を
開放すると、ヒータ（３３）ｌ＼の通電が停止するため
、超ｔ［導体（１ａ〉は再び液体ヘリウムの温度に冷却
されて超電導状態となる。従っＣ５超電導体（１ａ〉を
介しｒｍ ２つの電流ループ１．及び■２が形成される
。Next, as shown in Figure 12, when the open/close switch (32) is opened, the heater (33) is de-energized, so the conductor (1a) is cooled to the temperature of liquid helium again. Therefore, two current loops 1 and 2 are formed through the C5 superconductor (1a).
この後、開閉スイッチ〈２２）を開放して電流ループＩ
、を無くしても、電流ループ■１は減衰することなく永
久電流として流れ続け、超電導マグネッ１〜として動作
する。After this, open the on/off switch (22) and the current loop I
Even if , is eliminated, current loop (1) continues to flow as a persistent current without attenuation, and operates as superconducting magnet (1).
こうして励磁された超電導巻線（１）を消磁する場合は
、第１０図のように開田スイッチ（３２）を閉成１７て
超電導体（１ａ）を抵抗器どし、超電導体（１ａ）で消
費されるジュール熱エネルギにより電流ループ■、を消
滅させる。To demagnetize the superconducting winding (1) excited in this way, close the Kaida switch (32) 17 as shown in Figure 10, connect the superconductor (1a) to the resistor, and consume it in the superconductor (1a). The Joule heat energy generated causes the current loop (2) to disappear.
［発明が解決しようとする課題１
従来の永久電流スイッチは以上のように、ヒータ回路〈
３）て′構成されているので、ヒータ（３３）の発熱に
より大量の寒剤（液体ヘリウム）が消費されると共に、
超電導体〈１＆）を間接Ｃド目こ加熱及び冷却する必要
があるなめ、スイッチング動作に時間がかかるという問
題点があった。[Problem to be solved by the invention 1 As described above, the conventional persistent current switch has a heater circuit.
3) Since the heater (33) generates heat, a large amount of cryogen (liquid helium) is consumed, and
Since the superconductor <1&) needs to be indirectly heated and cooled, there is a problem that the switching operation takes time.
この発明はＬ記のような問題点を解決するためになされ
たもので５寒剤を消費せずに短時間でスイッチング動作
できる永久電流スイッチを得ることを目的とする。This invention was made in order to solve the problems mentioned in item L, and aims to provide a persistent current switch that can perform switching operations in a short period of time without consuming cryogen.
［課題を解決するための手段］
この発明に係る永久＠流スイッチは、超電導巻線に直列
に接続されたセラミックス系超電導体と、このセラミッ
クス系超電導体に近接配置されて選択的に励磁されろ磁
界発生用巻線とを備えたものである。[Means for Solving the Problems] A permanent @flow switch according to the present invention includes a ceramic superconductor connected in series to a superconducting winding, and a ceramic superconductor that is placed close to the ceramic superconductor and selectively excited. It is equipped with a winding for generating a magnetic field.
［作用］
この発明においては、セラミックス系超電導体の環境磁
界を変化さぜ′で臨界電流値を変化させることにより、
寒剤を消費することなく且つ短時間にセラミックス系超
電導体を超電導状態及び常電導状態に切換える。[Function] In this invention, by changing the critical current value by changing the environmental magnetic field of the ceramic superconductor,
To switch a ceramic superconductor to a superconducting state and a normal conducting state in a short time without consuming a cryogen.
［実施例］
以下、この発明の一実施例を図について説明する。第１
図は、−の発明の−実りか１例を示す回路図であり、（
１）、（２〉、り２１）、（２２）、〈４）及び（５）
は前述と同様のものである。[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a circuit diagram showing one example of the fruits of the invention.
1), (2>, 21), (22), <4) and (5)
is the same as above.
（１＾）は超電導巻線（１）の２点ＡＢ間に直列接続さ
れたセラミックス系超電導体であり、例えば棒状に形成
されている。(1^) is a ceramic superconductor connected in series between two points AB of the superconducting winding (1), and is formed into a rod shape, for example.
（６）は永久電流スイッチとなる磁界発生回路であり、
磁界発生用電源〈６１）と、この磁界発生用電源（６１
）に直列接続された開閉スイッチ（６２〉と、セラミッ
クス系超電導体（１＾）と、このセラミックス系超電導
体〈１Δ）に巻回され且つ開田スイッチクロ２）により
選択的に励磁される磁界発生用巻線（６３）とから構成
されている。(6) is a magnetic field generation circuit that serves as a persistent current switch,
A power supply for generating a magnetic field (61) and a power supply for generating a magnetic field (61)
), a ceramic superconductor (1^), and a magnetic field that is wound around the ceramic superconductor (1Δ) and selectively excited by the Kaida switch 2). and a winding (63).
（７）はフライオスタラＩ−（４）内に真空層を介し１
１一つ液体ヘリウム槽〈５）に隣接して設けられた液体
窒素槽であり、磁界発生用巻線（６３）と共にセラミッ
クス系超電導体く１＾）を収納！〜、こ１１らを７７°
に程度に冷却している。(7) is inserted into Fly Ostara I-(4) through a vacuum layer.
This liquid nitrogen tank is located adjacent to the liquid helium tank (5), and houses the ceramic superconductor (1^) along with the magnetic field generation winding (63)! ~, these 11 and others 77°
It has cooled down to a certain degree.
第２図は第１図内の磁界発生用巻線（６３）及びセラミ
ックス系超電導体（１＾）を詳細に示す斜視図であり、
Ｈは開閉スイッチ（６２）が閉成されたときに磁界発生
用巻線（６３）から発生する磁界である。尚、セラミッ
クス系超電導体（１＾）としては、第３図に実線で示す
ように、合金系超電導体（破線参照）と比較して、臨界
電流値Ｊが環境磁界Ｈに対し著しく変化するものが用い
られている。FIG. 2 is a perspective view showing in detail the magnetic field generating winding (63) and the ceramic superconductor (1^) in FIG.
H is a magnetic field generated from the magnetic field generating winding (63) when the open/close switch (62) is closed. Furthermore, as a ceramic superconductor (1^), as shown by the solid line in Figure 3, the critical current value J changes significantly with respect to the environmental magnetic field H compared to the alloy superconductor (see broken line). is used.
次に、第３図の臨界電流特性図並びに第４図〜第６図の
回路図を参照しながら、第１図及び第２図に示したこの
発明の一実施例の動作について説明する。Next, the operation of the embodiment of the present invention shown in FIGS. 1 and 2 will be described with reference to the critical current characteristic diagram shown in FIG. 3 and the circuit diagrams shown in FIGS. 4 to 6.
通常は、第１図のように開閉スイッチ（２２）及び（６
２）が開放され、超電導巻線（１）は液体ヘリウム槽（
５）により４°に程度に冷却され、セラミックス系超電
導体（１＾）は液体窒素槽（７）により７ブに程度に冷
却されており、共に超電導状態にある。Normally, the open/close switch (22) and (6) are shown in Figure 1.
2) is opened, and the superconducting winding (1) is placed in the liquid helium bath (
5), and the ceramic superconductor (1^) is cooled to about 7 degrees by the liquid nitrogen tank (7), and both are in a superconducting state.
超電導巻線（１）を励磁する場合には、まず、第４図の
ように磁界発生回路（６）内の開閉スイッチ（６２）を
閉成し、磁界発生用電源（６１）から磁界発生用巻線（
６３）に電流１．を供給する。電流ＩＰにより励磁され
た磁界発生用巻線（６３）は、磁界Ｈを発生し、これを
環境磁界としてセラミックス系超電導体（１＾）に印加
する。環境磁界Ｈが印加されたセラミックス系超電導体
（１＾）は、第３図の臨界電流特性に従って、臨界電流
値Ｊが著しく減少する。When exciting the superconducting winding (1), first close the on/off switch (62) in the magnetic field generation circuit (6) as shown in Fig. 4, and then connect the magnetic field generation power source (61) to the magnetic field generation power source (61). Winding (
63) to the current 1. supply. The magnetic field generating winding (63) excited by the current IP generates a magnetic field H, which is applied as an environmental magnetic field to the ceramic superconductor (1^). In the ceramic superconductor (1^) to which the environmental magnetic field H is applied, the critical current value J significantly decreases according to the critical current characteristics shown in FIG.
この状態で、第５図のように励磁回路（２）内の開閉ス
イッチ（２２）を閉成し、励磁用電源（２１）から電流
ＩＮを供給すると、セラミックス系超電導体（１＾）は
、微少電流により瞬時に常電導状態となり、抵抗器とし
て作用する。このとき、液体窒素温度におけるセラミッ
クス系超電導体（ｌ＾）の抵抗率は、数端Ω・ｅｌｌで
あるため、電流ＩＮは全て超電導巻線（１）に流れる。In this state, when the on-off switch (22) in the excitation circuit (2) is closed and current IN is supplied from the excitation power source (21) as shown in Fig. 5, the ceramic superconductor (1^) It instantaneously becomes a normal conductive state due to a small amount of current, and acts as a resistor. At this time, since the resistivity of the ceramic superconductor (l^) at the liquid nitrogen temperature is a few fractions of Ω·ell, all of the current IN flows through the superconducting winding (1).
続いて、第６図のように開閉スイッチ（６２）を開放す
ると、環境磁界Ｈが無くなり臨界電流値Ｊが増加するた
め、セラミックス系超電導体（１＾）は瞬時に超電導状
態となる。従って、前述と同様に、セラミックス系超電
導体（１＾）を介した２つの電流ループ１１及びＩ、が
形成され、その後、開閉スイッチ（２２）を開放しても
、電流ループ■、は減衰することなく永久電流として流
れ続ける。Subsequently, when the open/close switch (62) is opened as shown in FIG. 6, the environmental magnetic field H disappears and the critical current value J increases, so that the ceramic superconductor (1^) instantly enters a superconducting state. Therefore, as described above, two current loops 11 and I are formed via the ceramic superconductor (1^), and even if the on/off switch (22) is subsequently opened, the current loop (1) is attenuated. It continues to flow as a permanent current.
励磁された超電導巻線（１）を消磁する場合は、第４図
のように開閉スイッチ（６２）を閉成し、セラミックス
系超電導体（１＾）を再び抵抗器とすればよい。When demagnetizing the excited superconducting winding (1), the on/off switch (62) is closed as shown in FIG. 4, and the ceramic superconductor (1^) is used as a resistor again.
尚、上記実施例では、セラミックス系超電導体（１＾）
を棒状に形成し、これに磁界発生用巻線（６３）を巻回
した構成としたが、セラミックス系超電導体（１＾）を
巻線状に形成し、これに磁界発生用巻線（６３）を近接
配置してもよい。In the above example, the ceramic superconductor (1^)
was formed into a rod shape, and the magnetic field generation winding (63) was wound around it. However, the ceramic superconductor (1^) was formed into a wire shape, and the magnetic field generation winding (63) was wound around it. ) may be placed close together.
［発明の効果］
以上のようにこの発明によれば、超電導巻線に直列に接
続されたセラミックス系超電導体と、このセラミックス
系超電導体に近接配置されて選択的に励磁される磁界発
生用巻線とを設け、セラミックス系超電導体の環境磁界
により臨界電流値を変化させるようにしたので、寒剤を
消費することなく短時間に動作可能な永久電流スイッチ
が得られる効果がある。[Effects of the Invention] As described above, according to the present invention, there is provided a ceramic superconductor connected in series to a superconducting winding, and a magnetic field generating winding disposed close to the ceramic superconductor and selectively excited. Since the critical current value is changed by the environmental magnetic field of the ceramic superconductor, it is possible to obtain a persistent current switch that can be operated in a short time without consuming cryogen.
第１図はこの発明の一実施例を示す回路図、第２図は第
１図内の要部を示す斜視図、第３図は第１図内のセラミ
ックス系超電導体の環境磁界に対する臨界電流値を示す
特性図、第４図乃至第６図はそれぞれ第１図の動作を説
明するための回路図、第７図は従来の永久電流スイッチ
を示す回路図、第８図及び第９図は第７図内の２点鎖線
内を示す縦断面図及び横断面図、第１０図乃至第１２図
はそれぞれ第７図の動作を説明するための回路図である
。
（１）・・・超電導巻線
（１＾）・・・セラミックス系超電導体（６）・・・磁
界発生回路
（６１）・・・磁界発生用電源 （６２）・・・開閉ス
イッチ（６３）・・・磁界発生用巻線
Ｈ・・・環境磁界
尚、図中、同一符号は同−又は相当部分を示す。Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a perspective view showing the main parts in Fig. 1, and Fig. 3 is the critical current of the ceramic superconductor shown in Fig. 1 in response to an environmental magnetic field. Figures 4 to 6 are circuit diagrams for explaining the operation of Figure 1, Figure 7 is a circuit diagram showing a conventional persistent current switch, and Figures 8 and 9 are characteristic diagrams showing the values. A longitudinal cross-sectional view and a cross-sectional view showing the area within the two-dot chain line in FIG. 7, and FIGS. 10 to 12 are circuit diagrams for explaining the operation of FIG. 7, respectively. (1)...Superconducting winding (1^)...Ceramic superconductor (6)...Magnetic field generation circuit (61)...Magnetic field generation power supply (62)...Open/close switch (63) ...Magnetic field generating winding H...Environmental magnetic field In the drawings, the same reference numerals indicate the same or corresponding parts.
Claims (1)
と、このセラミックス系超電導体に近接配置されて選択
的に励磁される磁界発生用巻線とを備えた永久電流スイ
ッチ。A persistent current switch comprising a ceramic superconductor connected in series to a superconducting winding, and a magnetic field generating winding disposed close to the ceramic superconductor and selectively excited.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63042188A JPH01217902A (en) | 1988-02-26 | 1988-02-26 | Persistent current switch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63042188A JPH01217902A (en) | 1988-02-26 | 1988-02-26 | Persistent current switch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01217902A true JPH01217902A (en) | 1989-08-31 |
Family
ID=12629030
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63042188A Pending JPH01217902A (en) | 1988-02-26 | 1988-02-26 | Persistent current switch |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01217902A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2704367A1 (en) * | 1993-04-20 | 1994-10-28 | Gec Alsthom Electromec | Superconducting current limiter with adjustable datum value |
-
1988
- 1988-02-26 JP JP63042188A patent/JPH01217902A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2704367A1 (en) * | 1993-04-20 | 1994-10-28 | Gec Alsthom Electromec | Superconducting current limiter with adjustable datum value |
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