JPS60196908A - Superconductive device - Google Patents

Abstract

PURPOSE:To make the titled semiconductor device small in size as well as to contrive accomplishment of lightweight by a method wherein an auxiliary permanent current switch is formed into small capacitance. CONSTITUTION:A main permanent current switch 6 is series-connected to the series circuit of the first and the second superconductive coils 1 and 2 independently from an auxiliary permanent current switch 7, and a closed circuit whereon main current I1 will run in a permanent mode is formed. As a result, the auxiliary permanent current switch 7 is series-connected to the second superconductive coil 2 independently from the main permanent current switch, and a closed circuit whereon an auxiliary current I2 runs in a permanent current mode is formed. Accordingly, the main current I1 running on the auxiliary permanent current switch 7 as seen in the prior art can be prevented, and an auxiliary current I2 alone runs there. As a result, the auxiliary permanent current switch 7 of small capacitance wherein the auxiliary current I2 required for performance of a fine adjustment is sufficient enough for accomplishment of function required for this device.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a superconducting device, and is particularly suitable for a nuclear magnetic resonance imaging device, etc., and is suitable for a plurality of series-connected superconducting coils that require fine current adjustment. Regarding superconducting devices equipped with superconducting coils [Background of the Invention] Superconducting devices that require a highly accurate and uniform magnetic field, such as nuclear magnetic resonance imaging devices, are equipped with a plurality of superconducting coils connected in series. , it is necessary to fine-tune the current flowing through some of these superconducting coils.

FIG. 1 is an electrical circuit diagram of a conventional superconducting device.

In this figure, reference numeral 1.2 denotes first and second superconducting coils connected in series.

Among them, the second superconducting coil 2 requires fine adjustment of the current. The series circuit of the first and second superconducting coils 1 and 2 includes a main power switch 3. Mains power 5 through 4
are connected in series, and a main persistent current switch 6 and an auxiliary persistent current switch 7 are separately connected in series to each of the first and second superconducting coils 1.2,
Further, an auxiliary power supply 9 is connected in series with the second superconducting coil 2 and in parallel with the auxiliary persistent current switch 7 via an auxiliary power supply switch 8 .

In the superconducting device configured in this way, with the main and auxiliary persistent current switches 6.7 and the auxiliary power switch 8 open, first, the main power switch 3.4 is closed and the main power supply 5 is turned on.
the main electrician, with the first and second superconducting coils l,
2, and then when fine adjustment of the current is required, close the auxiliary power switch 8 to turn on the auxiliary current I from the auxiliary power supply 9.
By adding 2, the current I3 (=11 + I2) flowing through the second superconducting coil 2 is finely adjusted. Thereafter, by closing the main and auxiliary persistent current switches 6.7 and then opening the main and auxiliary power switches 3 and 4.8, the first and second superconducting coils 1.2 and the main and auxiliary persistent current The main current is passed through the closed circuit of the switch 6.7, and the persistent current mode is set in which the auxiliary current I2 is caused to flow through the closed circuit of the second superconducting coil 2 and the auxiliary persistent current switch 7.

Therefore, the current flowing through the main persistent current switch 6 is the main current current, and the current flowing through the auxiliary persistent current switch 7 is the sum of the main current current and the auxiliary current I2, or 11+l2=I
It becomes 3. Here, the auxiliary current generator 2 is used to correct the non-uniformity of the magnetic field due to errors in the number of turns of the second superconducting coil 20, the shape 9 position, etc., and is sufficiently small compared to the main current generator. , -:I, so both the main and auxiliary persistent current switches 6.7 must have a capacity sufficient to conduct current to the main electrician.

In addition, in Fig. 2, the second superconducting coil is 2A.

FIG. 2B is an electrical circuit diagram of a conventional superconducting device connected in series with two or 1' (1) superconducting pools 2B; In the superconducting device shown in FIG. 2, as in the conventional example shown in FIG. The first and second superconducting coils 1 are connected in series.
．． The VCs of 2A and 2B are each connected in series with a main persistent current switch 6 and auxiliary persistent current switches 7A and 7B, and are further connected in series with each second superconducting coil 2A and 2B and with each auxiliary persistent current switch 7A and 7B. In parallel, separate auxiliary power supplies 9A and 9B are connected via separate auxiliary power switches 8A and 8B.

Therefore, in this case as well, the current flowing through the main persistent current switch 6 is the main current I□, and the current flowing through each auxiliary persistent current switch 7A, 7B is the main current 11 and each auxiliary power source 9.
The sum of each auxiliary current l2AeI2B due to A and 9B, that is, 11 +" 2 A = "B A eI + I2B"
I3B, the main and each auxiliary persistent current switch 6,
7A and 7B must have a capacity sufficient to carry the main current I8, as in the conventional example shown in FIG.

In other words, conventional superconducting devices of this type require as many persistent current switches as large as the number of superconducting coils to carry the main current, and as a result, the space for installing the persistent current switches must also be large. 9. Compactness of the entire device. This was an impediment to weight reduction.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a superconducting device of this kind, which eliminates the drawbacks of the prior art described above, reduces the capacity of the auxiliary persistent current switch, and reduces the size and weight of the entire device.

[Summary of the invention]

To achieve this objective, the present invention provides a main persistent current switch that is independently connected in series with a series circuit of first and second superconducting coils separately from an auxiliary persistent current switch to form a closed circuit, and an auxiliary persistent current switch. By connecting the persistent current switch separately from the main persistent current switch in series with the second superconducting coil to form a closed circuit, the main current □ does not flow to the auxiliary persistent current switch, and it is used for fine adjustment. The present invention is characterized in that only the auxiliary current E2 having a small value of is made to flow.

[Embodiments of the invention]

Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 3 is an electrical circuit diagram of a superconducting device showing an embodiment of the present invention, which corresponds to the conventional example shown in FIG. In FIG. 3, the same reference numerals as in FIG. 1 indicate the same or equivalent parts.

This embodiment differs from the conventional example shown in FIG. 1 in the connection position of the main persistent current switch 6. That is, the main persistent current switch 6 is the first permanent current switch independently of the auxiliary persistent current switch 7.
and the second superconducting coil 1°zf) are connected in series to form a closed circuit in which the main current 1 flows in persistent current mode. As a result, the auxiliary persistent current switch 7 is independently connected in series with the second superconducting coil 2 in addition to the main persistent current switch 6, and a closed circuit is formed in which the auxiliary current switch 2 flows in the persistent current mode. Become.

Therefore, the first superconducting coil 1 and the second super main current 1
1 and the auxiliary current switch 2 (=I, 1×2) flow respectively, and the main persistent current switch 6 also receives the main current 11 as in the conventional case, but the auxiliary persistent current switch 7
, the main current does not flow as in the past, but the auxiliary current I2
only will flow. Therefore, it is sufficient to use a small-capacity auxiliary persistent current switch 7 that allows only the auxiliary current I2, which is a small current for fine adjustment, to flow.

Further, FIG. 4 is an electrical circuit diagram of a superconducting device showing another embodiment of the present invention corresponding to the conventional example shown in FIG. In FIG. 4, the same reference numerals as in FIG. 2 indicate the same or equivalent parts.

This embodiment differs from the conventional example shown in FIG. 2 in the connection position of the main persistent current switch 6, as in the previous embodiment. That is, the main persistent current switch 6 independently connects the first and second superconducting coils 1 and 2A, separately from each of the auxiliary persistent current switches 7A and 7B.

It is connected in series with the series circuit of 2B to form a closed circuit in which the main electrician 1 flows in persistent current mode. As a result, each of the auxiliary persistent current switches 7A and 7B is independently connected in series with the second superconducting coils 2A and 2B separately from the main persistent current switch 6, and the auxiliary current l2AeI2B is separately connected in the persistent current mode. Each flowing closed circuit will be formed. - Therefore, in this embodiment, as in the previous embodiment, the first superconducting coil l and each second superconducting coil 2A
, 2B includes a main current worker, a main current worker 11 and an auxiliary current worker 2.
AII2B sum current 13 people (=L +I2A L I
an (=It + I2B) respectively, and the main current ■1 also flows through the main persistent current switch 6, but the main current I does not flow through each of the auxiliary persistent current switches 7A and 7B.
Only each auxiliary current I2A*■211 will flow.

For this reason, it is sufficient to use a small-capacity switch as each of the auxiliary persistent current switches 7A and 7B that is sufficient to flow each auxiliary current switch 2AtI2B, which is a small current for fine adjustment.

Note that the second superconducting coil is 1 as in each of the above embodiments.
The present invention is not limited to the case of 1 or 2, but can be similarly applied to the case of 3 or more.

〔Effect of the invention〕

As explained above, according to the present invention, no main current flows through the auxiliary persistent current switch, and only a small auxiliary current for fine adjustment flows, so the capacity of the auxiliary persistent current switch can be reduced, and the superconducting device can be Small size.

It can be made lighter.

[Brief explanation of the drawing]

FIGS. 1 and 2 are electrical circuit diagrams showing different conventional superconducting devices, and FIGS. 3 and 4 are electrical circuit diagrams showing superconducting devices according to different embodiments of the present invention. l...First superconducting coil, 2, 2A, 2B.
...Second superconducting coil, 3,4...Main power switch, 5...Main power supply, 6.Old...Main persistent current switch, 7.7A, 7B. ...Auxiliary persistent current switch, 8°8A, 8B...Auxiliary power switch, 9,9A. 9B...Auxiliary power supply. Figure 1 Figure 2 Figure 3 Steam Figure 4

Claims (1)

[Claims] 1. A first superconducting coil and a second superconducting coil connected in series.
a superconducting coil, a main power supply connected in series to this series circuit via a main power switch, and a series circuit of the main power supply and the main power switch connected in series with the series circuit of the first and second superconducting coils. an auxiliary power source connected in series to the second superconducting coil via an auxiliary power switch; In the device comprising a series circuit of switches and an auxiliary persistent current switch connected in parallel, the main persistent current switch is independently connected to the first persistent current switch separately from the auxiliary persistent current switch.
and the auxiliary persistent current switch is connected in series with a series circuit of a second superconducting coil to form a closed circuit, and the auxiliary persistent current switch is independently connected in series with the second superconducting coil separately from the main persistent current switch. A superconducting device characterized by forming a closed circuit. 2. Claim 1, characterized in that the second superconducting coil is plural, and the auxiliary persistent current switch is connected in series for each of these superconducting coils to form a separate closed circuit. A superconducting device.