JP6862382B2 - High-temperature superconducting magnet device, its operation control device and method - Google Patents

Description

An embodiment of the present invention relates to a high-temperature superconducting magnet device including a high-temperature superconducting coil and a superconducting switch connected in parallel to the high-temperature superconducting coil, an operation control device and a method thereof.

Superconducting devices such as Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) require extremely high time stability on the order of ppm for magnetic fields generated over a long period of time. .. Therefore, an electric switch called a permanent current switch may be connected in parallel with the superconducting coil.

The permanent current switch is a superconducting switch generally made of a superconducting wire. In principle, this superconducting switch has a closed loop with zero electrical resistance when cooled below the superconducting transition temperature, so that a very stable magnetic field without current attenuation (magnetic field attenuation) can be generated.

Operating in this way is called a permanent current mode. The superconducting switch for forming the closed loop is switched (on, off) by utilizing the temperature change. For example, at the time of excitation, in order to prevent the flow to the superconducting switch and supply the current to the superconducting coil body, a method of heating the superconducting switch to a high resistance (off) by heating it to a temperature higher than the normal conduction temperature using a heater or the like is adopted. Has been done. In this case, in order to form a closed loop after excitation and shift to steady operation, the heater or the like may be turned off and cooled, and the superconducting switch may be returned to the superconducting state (on).

If a resistance component R is generated at the connection part such as the connection part between the superconducting coil and the superconducting switch, the current is attenuated (magnetic field attenuation) at the time constant L / R of the circuit determined by the inductance L of the superconducting coil. It ends up. Therefore, for example, a so-called superconducting connection technique is used in which superconducting wires (filaments) are directly connected to each other by pressure welding, spot welding, heat treatment, etc. to connect them to extremely low resistance on the order of 1E-10Ω to 1E-13Ω. There is.

Examples of the superconducting wire used for such a superconducting coil include _{oxide high-temperature superconducting wires such as Bi 2} Sr ₂ Ca ₂ Cu ₃ O _10-δ wire and REB ₂ C ₃ O _7-δ wire (high-temperature superconducting wire). ) Has been actively studied in recent years.

A superconducting coil using a high-temperature superconducting wire has a high critical current density even at a high temperature of 20K to 50K as compared with a conventional low-temperature superconducting wire such as NbTi, so that the coil can be miniaturized by high-current density operation. It is preferable that the superconducting wire used for the superconducting switch is also manufactured by using the same high-temperature superconducting wire because the cooling structure can be further simplified by designing the superconducting wire at the same operating temperature as the superconducting coil.

However, in such a high-temperature superconducting wire, since the superconducting layer is a thin film of an oxide having a very brittle oxide, the superconducting connection technology as described above has not been established at present. Therefore, it is connected by a general solder connection via solder. Since this solder connection produces a resistance component larger than that of the superconducting connection, the current is attenuated, which makes it difficult to operate in the permanent current mode.

On the other hand, there is also a method in which the superconducting switches are not connected in parallel and are always driven by a power source like a normal superconducting magnet, but the time stability deteriorates due to the current ripple of the power source.

Therefore, for example, Patent Document 1 or 2 includes a superconducting switch connected in parallel to the high-temperature superconducting coil and a power supply circuit for supplying a current to the high-temperature superconducting coil. These documents propose a method of connecting a compensating resistor having a resistance value about 1 to 1000 times larger than the resistance component of the high-temperature superconducting coil in series with the superconducting switch. According to this method, it is possible to compensate for the voltage drop caused by the resistance component of the high-temperature superconducting coil and to generate a magnetic field that is highly stable in time even when driven by a power source.

Japanese Patent No. 4291560 Japanese Patent No. 4896620

However, in the above-mentioned method, the current divided by the resistance ratio between the resistance component of the superconducting switch and the compensating resistor and the resistance component of the high-temperature superconducting coil always flows through the compensating resistor. Therefore, it was necessary to increase the energizing current value of the power supply to be higher than the current value required for generating the magnetic field, and to supply the surplus current from the power supply.

On the other hand, when the compensating resistor is not used, it is not necessary to supply the surplus current, but when the superconducting switch is turned on after excitation, the current is gradually divided into the superconducting switch at the time constant L / R of the circuit. Therefore, there is a problem that the current value of the high-temperature superconducting coil is reduced and the current is attenuated (magnetic field attenuation) as in the operation in the permanent current mode described above.

As a means for returning the current diverted to the superconducting switch to the high-temperature superconducting coil, for example, there is a method of heating the superconducting switch to a temperature higher than the normal conduction transition temperature with a heater or the like to bring it into a high resistance state.

However, this method has a problem that the superconducting switch must be recooled in order to restart the operation after that, and the larger the heat capacity of the superconducting switch, the longer the waiting time until the superconducting switch is restarted. there were.

An object to be solved by the present embodiment is to provide a high-temperature superconducting magnet device capable of compensating for current attenuation (magnetic field attenuation) in a short time without requiring supply of excess current.

In order to solve the above problems, the high-temperature superconducting magnet device according to the present embodiment is connected to a high-temperature superconducting coil, an exciting power source connected to the high-temperature superconducting coil to supply an electric current, and the exciting power source, and is connected to the high-temperature superconducting coil. It is characterized by having a superconducting switch electrically connected in parallel with the coil, and providing a temperature control unit in a section having a smaller heat capacity than the superconducting switch in the connection path between the exciting power supply and the superconducting switch. To do.

The operation control device of the high-temperature superconducting magnet device according to the present embodiment is connected to the high-temperature superconducting coil, an exciting power source connected to the high-temperature superconducting coil to supply a current, and the exciting power source, and is connected in parallel with the high-temperature superconducting coil. Controls the operation of a high-temperature superconducting magnet device provided with an electrically connected superconducting switch and provided with a temperature control unit in a section having a smaller heat capacity than the superconducting switch in the connection path between the exciting power supply and the superconducting switch. The operation control device of the high-temperature superconducting magnet device, which measures the temperature corresponding to the resistance value of the section of the connection path in which the magnetic field measuring unit for measuring the generated magnetic field of the high-temperature superconducting coil and the temperature control unit are provided. When the temperature measuring unit to be measured and the generated magnetic field approach the magnetic field corresponding to the lower limit of the rated current value, the resistance value of the section of the connection path provided with the temperature control unit is the resistance of the high temperature superconducting coil. It is characterized by including a control unit that controls to increase the resistance value until it becomes higher than the value.

The operation control method of the high-temperature superconducting magnet device according to the present embodiment includes a high-temperature superconducting coil, an exciting power source connected to the high-temperature superconducting coil to supply a current, and connected to the exciting power source in parallel with the high-temperature superconducting coil. Controls the operation of a high-temperature superconducting magnet device provided with an electrically connected superconducting switch and provided with a temperature control unit in a section having a smaller heat capacity than the superconducting switch in the connection path between the exciting power supply and the superconducting switch. This is an operation control method for a high-temperature superconducting magnet device, in which a magnetic field measuring step for measuring the generated magnetic field of the high-temperature superconducting coil and a temperature corresponding to a resistance value in a section of the connection path provided with the temperature control unit are set. When the temperature measurement step to be measured and the generated magnetic field approach the magnetic field corresponding to the lower limit of the rated current value, the resistance value of the section of the connection path provided with the temperature control unit is the resistance of the high temperature superconducting coil. It is characterized by having a control step of controlling the resistance value to be increased until it becomes higher than the value.

According to the present embodiment, it is possible to provide a high-temperature superconducting magnet device capable of compensating for current attenuation (magnetic field attenuation) in a short time without requiring supply of excess current.

It is a circuit diagram which shows the high temperature superconducting magnet apparatus of 1st Embodiment. It is an enlarged sectional view which shows the connection part of the high temperature superconducting magnet apparatus of 1st Embodiment. It is a block diagram which shows an example of the high temperature superconducting wire used for the high temperature superconducting magnet apparatus of 1st Embodiment. It is a timing chart which shows an example of the energization pattern of the high temperature superconducting magnet apparatus of 1st Embodiment. It is a circuit diagram which shows the high temperature superconducting magnet apparatus of 2nd Embodiment. It is a circuit diagram which shows the high temperature superconducting magnet apparatus of 3rd Embodiment. It is an enlarged sectional view which shows the connection part of the high temperature superconducting magnet apparatus of 3rd Embodiment. It is an enlarged sectional view which shows the connection part of the high temperature superconducting magnet apparatus which shows 4th Embodiment.

Hereinafter, the high-temperature superconducting magnet device, its operation control device, and the method according to the present embodiment will be described with reference to the drawings.

(First Embodiment)
(Constitution)
FIG. 1 is a circuit diagram showing a high-temperature superconducting magnet device according to the first embodiment. FIG. 2 is an enlarged cross-sectional view showing a connection portion of the high-temperature superconducting magnet device of the first embodiment. FIG. 3 is a configuration diagram showing an example of a high-temperature superconducting wire used in the high-temperature superconducting magnet device of the first embodiment. FIG. 4 is a timing chart showing an example of the energization pattern of the high-temperature superconducting magnet device of the first embodiment.

In the high-temperature superconducting magnet device of the present embodiment, as shown in FIG. 1, the high-temperature superconducting coil 1 and the exciting power source 5 for constantly supplying an electric current to the high-temperature superconducting coil 1 are electrically connected. A superconducting switch 2 is electrically connected in parallel to the high-temperature superconducting coil 1.

A heater 3, which is a heating mechanism, is electrically insulated from the superconducting switch 2 in order to change the resistance value according to a temperature change, but is thermally connected to the superconducting switch 2.

The superconducting switch 2 is brought into a normal conducting state (off) by raising the temperature to the superconducting transition temperature Tc or higher due to the heat generated by the heater 3, and high resistance is generated. On the other hand, in the state where the heater 3 does not generate heat, the superconducting switch 2 is cooled to the same temperature as the high-temperature superconducting coil 1 by a heat transfer plate thermally connected to a refrigerator as a cooling mechanism (not shown). It goes into a state (on) and generates low resistance. Here, when the superconducting switch 2 is recooled, it is cooled to at least the superconducting transition temperature Tc or less, and is actually cooled to the operating temperature.

In a part of the connection path between the exciting power supply 5 and the high temperature superconducting coil 1, gold, silver, copper, iron, stainless steel, aluminum, copper alloy, iron alloy, etc. are always used from the exciting power supply 5 as shown in FIG. A current feeder wire 11 formed by bonding a superconducting wire to the conductive metal or the normal conductive metal is drawn out.

In the connection path between the exciting power supply 5 and the high-temperature superconducting coil 1, there are at least one connection portion 12a and 12b with the high-temperature superconducting coil 1 (two locations in this embodiment). That is, the exciting power source 5 and the high-temperature superconducting coil 1 are electrically connected via the connecting portions 12a and 12b. These connecting portions 12a and 12b are formed by connecting means such as solder connection, pressure welding, and spot welding to generate a finite connection resistance.

Further, the exciting power supply 5 and the superconducting switch 2 are electrically connected via the connecting portions 13a and 13b. Even in a part of the connection path between the exciting power supply 5 and the superconducting switch 2, a connection resistance is generated at the connection portions 13a and 13b as in the connection portions 12a and 12b.

In the high-temperature superconducting magnet device of the present embodiment, as shown in FIG. 2, a solder layer 6 is interposed between the current feeder wire 11 drawn from the exciting power supply 5 and the high-temperature superconducting wire 21 drawn from the superconducting switch 2. It is connected by the connecting portion 13a.

Although the heater 4 as a temperature control unit for changing the resistance value is electrically insulated from the connection portion 13a, it is thermally connected. The length of a part of the section where the heater 4 which is the temperature control unit is provided is set so that the heat capacity is smaller than that of the superconducting switch 2.

In the present embodiment, similarly to the heater 3 provided in the superconducting switch 2, in a state where the heater 4 does not generate heat, the connection portion 13a is a high-temperature superconducting coil by a heat transfer plate thermally connected to a refrigerator (not shown). It is preferable to cool to the same temperature as 1. Although only the heater 4 is shown as a temperature control unit in FIG. 1, it is assumed that a cooling mechanism using a heat transfer plate thermally connected to the refrigerator is included in addition to other heating mechanisms.

Further, the connecting portion 13a may be formed not by soldering but by a connecting method such as pressure welding or spot welding as described above.

Next, the configuration of the operation control system of the present embodiment will be described.

As shown in FIG. 1, the generated magnetic field of the high-temperature superconducting coil 1 is measured by a magnetic field measuring unit 7 such as a Hall element or an NMR (Nuclear Magnetic Resonance) probe. The temperature in the section of the connection path between the exciting power source 5 provided with the heater 4 and the superconducting switch 2 is measured by a temperature measuring unit 8 such as a resistance thermometer. The temperature measured by the temperature measuring unit 8 corresponds to the resistance value in the section of the connection path.

The magnetic field measurement signal indicating the magnetic field measured by the magnetic field measuring unit 7 and the temperature measuring signal indicating the temperature measured by the temperature measuring unit 8 are output to the control unit 9, respectively. The control unit 9 controls the operation of the high-temperature superconducting magnet device as described later by obtaining these signals and controlling the resistance value of the heater 4.

The control unit 9 is mainly composed of a well-known microcomputer equipped with a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory) as a recording medium, an I / O (Input / Output), and the like. It is a controlled device.

Of these, the ROM stores data and programs that need to retain the stored contents even when the power is turned off. The RAM temporarily stores data. The CPU realizes each function by executing a program installed in the ROM.

Next, the configuration of the high-temperature superconducting wire 21 will be described with reference to FIG.

As shown in FIG. 3, the high-temperature superconducting wire 21 is entirely formed in a tape shape. The high-temperature superconducting wire 21 is, for example, a thin film called a coated conductor in which an intermediate layer 25, a superconducting layer 26, a protective layer 29, and both sides thereof are coated with a stabilizing layer 27 on a metal tape substrate 24, for example. It is a high-temperature superconducting wire.

The high-temperature superconducting wire 21 may be provided with an orientation layer 28 between the tape substrate 24 and the intermediate layer 25, if necessary. The tape substrate 24 is made of a material such as stainless steel, a nickel alloy such as Hastelloy, or a silver alloy.

The intermediate layer 25 is a diffusion prevention layer, and is made of, for example, cerium oxide, yttria-stabilized zirconia (YSZ: Yttria-Stabilized Zirconia), magnesium oxide, ytttrium oxide, ytterbium oxide, barium zirconia, and the like, and is formed on the tape substrate 24. Is formed in.

The superconducting layer 26 is made of, for example, an oxide superconductor thin film having _{a RE 123-} based composition (REB ₂ C ₃ O _{7-δ, etc.).} In addition, "_{RE" of "REB 2} C ₃ O _7-δ " is at least one of rare earth elements (for example, neodymium (Nd), gadolinium (Gd), holmium (Ho), samarium (Sm), etc.) and yttrium element. , "B" means samarium (Ba), "C" means copper (Cu), and "O" means oxygen (O).

The stabilizing layer 27 is provided for the purpose of preventing the superconducting layer 26 from burning when excessive electricity flows through the superconducting layer 26, and is formed of, for example, conductive copper or silver.

The alignment layer 28 is provided for the purpose of aligning and forming the intermediate layer 25 on the tape substrate 24, and is formed of magnesium oxide (MgO) or the like. The alignment layer 28 can be omitted when an oriented substrate is used.

The protective layer 29 is provided for the purpose of preventing the superconducting layer 26 from deteriorating due to contact with moisture in the air, and is formed of silver or the like. The protective layer 29 also plays a role of preventing the superconducting layer 26 from burning when excessive electricity flows through the superconducting layer 26.

The tape width w of the high-temperature superconducting wire 21 composed of such a multilayer is very thin, for example, 4 to 12 mm and the tape thickness is 0.1 to 0.2 mm. The resistance value per unit cross-sectional area is higher than that of the current feeder wire 11.

In the present embodiment, the high-temperature superconducting wire 21 may be an insulating coated high-temperature superconducting wire in which the periphery of the high-temperature superconducting wire 21 is coated with an insulating material such as polyimide or polyimideamide. Further, the high-temperature superconducting wire 21 of the present embodiment does not necessarily have to be provided with the stabilizing layer 27.

(Operation control method)
Next, the operation control method of the high-temperature superconducting magnet device in the present embodiment will be described using the energization patterns shown in FIGS. 1 and 4.

In the circuit diagram shown in FIG. 1, the high-temperature superconducting coil 1 is composed of an inductance L, a flux flow resistance in which a high-temperature superconducting wire is generated inside the coil, a connection resistance between the high-temperature superconducting wires in the coil, and a plurality of coils. It can be expressed equivalently by the sum of the connection resistance between the coils and the resistance component R composed of the coils.

First, the superconducting switch 2 is turned off (the heater 3 is turned on), and the heater 4 in the connection path is turned off to start the excitation of the high-temperature superconducting coil 1 by the exciting power source 5. In this case, the superconducting switch 2 has a high resistance because the superconducting transition temperature is Tc or higher, and almost all the current from the exciting power supply 5 is supplied to the high-temperature superconducting coil 1 side, and the rated current value is as shown in FIG. When I ₀ is reached, excitation is completed.

At this time, the high resistance at off required for the superconducting switch 2 must be high enough to limit the diversion by the induced voltage L (dI / dt) at the time of excitation, although it depends on the exciting speed. Further, from the viewpoint of the emergency shutoff operation in which the magnetic energy accumulated in the coil is consumed by the protection resistance when the excitation power supply 5 is cut off in an emergency, a resistance value on the order of several hundred mΩ to several tens of Ω, which is higher than the protection resistance, is required. Be done.

Therefore, in order to obtain a desired resistance value, it is necessary to set the length of the superconducting wire to be long, and the superconducting switch 2 is generally composed of a non-inductive winding coil.

After that, the heater 3 of the superconducting switch 2 is turned off, the superconducting switch 2 is cooled to enter the superconducting state (on), and the operation is started. At this time, even if the current value output by the exciting power supply 5 is constant, the circuit resistance R calculated by the sum of the resistance component of the high temperature superconducting coil 1 and the resistance components of the other connecting portions 12a, 12b, 13a, 13b. Due to the time constant L / R of the circuit determined by the above, the energizing current value I flowing through the high temperature superconducting coil 1 _{gradually attenuates from the rated current value I 0 as} shown in the wavy line comparative example of FIG.

In the operation control method of the present embodiment, when the energizing current value I approaches the current value set at the lower limit of the rated current value, the control unit 9 controls the heater 4 in the connection path to generate heat, thereby causing the connection unit to generate heat. The resistance value of 13a is increased so as to be higher than the resistance component of the high-temperature superconducting coil 1.

When the resistance component Rcoil consisting of the high-temperature superconducting coil 1 and the connecting portions 12a and 12b and the resistance component Rs consisting of the superconducting switch 2 and the connecting portions 13a and 13b are used, the energizing current value I flowing through the high-temperature superconducting coil 1 is
I = I ₀ × (Rs / (Rs + Rcoil)) = I ₀ × (1 / (1+ (Rcoil / Rs)))
Is. Therefore, the energizing current value I returns to the _{rated current value I 0 as the resistance component Rs rises.}

Since the heat generated by the heater 4 in the connection path becomes a heat load on the cooling system, the heater 4 in the connection path is turned off after the return. Then, when the energizing current value I approaches the current value set at the lower limit of the rated current value again, the current attenuation (magnetic field attenuation) is compensated by repeating the same process as described above.

In this way, when the generated magnetic field measured by the magnetic field measuring unit 7 approaches the magnetic field corresponding to the lower limit of the rated current value, the control unit 9 has a high resistance value in the section of the connection path in which the heater 4 is provided. The resistance value is controlled to be increased until it becomes higher than the resistance value of the superconducting coil 1. In this case, the resistance value in the section of the connection path provided with the heater 4 corresponds to the temperature measured by the temperature measuring unit 8.

The energizing current value I may be used as a measuring means using a so-called shunt resistor, but it will increase the circuit resistance R. Therefore, it is preferable that the generated magnetic field of the high-temperature superconducting coil, which is proportional to the energizing current value I, is monitored by a magnetic field measuring unit 7 such as the Hall element or an NMR (Nuclear Magnetic Resonance) probe described above, and calculated back.

(For use)
In the present embodiment configured as described above, temperature control is possible in a part of the connection path between the exciting power supply 5 and the superconducting switch 2. Further, the resistance component of the connection portion 13a does not need to have a resistance value higher than the protection resistance from the viewpoint of emergency cutoff unlike the superconducting switch 2.

The length of the section in which the heater 4 installed in the connection path is provided is set so that the heat capacity is smaller than that of the superconducting switch 2. Therefore, it is possible to generate a resistance component higher than that of the high-temperature superconducting coil 1 with a smaller amount of heating than heating the superconducting switch 2, and it is possible to recover in a shorter time than recooling the superconducting switch 2. ..

(Effect)
According to this embodiment, since it is not necessary to install the compensating resistor as in the conventional case, it is not necessary to supply the surplus current from the exciting power supply 1. Further, according to the present embodiment, it is possible to provide a high-temperature superconducting magnet device capable of compensating for current attenuation (magnetic field attenuation) in a short time.

In the present embodiment, an example in which the heater 4 as the temperature control unit is thermally connected to the connection portion 13a among the connection portions 13a and 13b has been described, but the present invention is not limited to this, and the heater 4 is heated to the connection portion 13b. May be connected. Even in this case, the same actions and effects as those of the above embodiment can be obtained.

(Second Embodiment)
(Constitution)
FIG. 5 is a circuit diagram showing the high-temperature superconducting magnet device of the second embodiment.

The same components as those in the first embodiment are designated by the same reference numerals, and redundant description will be omitted. Further, in FIG. 5, the illustration of the operation control system including the magnetic field measuring unit 7, the temperature measuring unit 8, and the control unit 9 is omitted.

The high-temperature superconducting magnet device of the present embodiment is connected via a solder layer 6 between the current feeder wire 11 drawn from the exciting power source 5 of the first embodiment and the high-temperature superconducting wire 21 drawn from the superconducting switch 2. The configuration in which the heater 4 as the temperature control unit is thermally connected to the unit 13a is changed as follows.

As shown in FIG. 5, in the high-temperature superconducting magnet device of the present embodiment, in the high-temperature superconducting wire 21a drawn from the superconducting switch 2, the heater 4a as a temperature control unit for changing the resistance is electrically insulated. However, it has a thermally connected configuration.

Since the configuration of the high-temperature superconducting wire 21a is the same as that of the high-temperature superconducting wire 21 shown in FIG. 3, the description thereof will be omitted. Further, although only the heater 4a is shown as the temperature control unit in FIG. 5, in addition to other heating mechanisms, a cooling mechanism by a heat transfer plate thermally connected to the refrigerator is included.

(For use)
In the present embodiment configured as described above, a part of the connection path between the exciting power supply 5 and the superconducting switch 2 in which the heater 4a as a temperature control unit for changing the resistance is installed is the superconducting switch 2. It is a high temperature superconducting wire 21a drawn from.

Therefore, the heat capacity per unit length can be reduced as compared with the first embodiment in which the heater 4a as the temperature control unit is thermally connected to the soldered connection portion 13a.

Since the operation control method of the present embodiment is the same as that of the first embodiment, the description thereof will be omitted.

(Effect)
According to the present embodiment, the heat capacity per unit length in a part of the connection path between the exciting power supply 5 and the superconducting switch 2 in which the heater 4a as the temperature control unit for changing the resistance is installed is determined. It can be made smaller than that of the first embodiment.

Therefore, it is possible to provide a high-temperature superconducting magnet device capable of generating a resistance component higher than that of the high-temperature superconducting coil 1 with a much smaller amount of heating and recovering in a shorter time.

In the present embodiment, the section in which the heater 4a is installed may be extended in the longitudinal direction of the high-temperature superconducting wire 21a, or a plurality of heaters 4a may be divided and provided.

(Third Embodiment)
(Constitution)
FIG. 6 is a circuit diagram showing a high-temperature superconducting magnet device according to a third embodiment. FIG. 7 is an enlarged cross-sectional view showing a connection portion of the high-temperature superconducting magnet device of the third embodiment.

The same configurations as those of the first and second embodiments are designated by the same reference numerals, and duplicate description will be omitted. Further, in FIG. 6, the illustration of the operation control system including the magnetic field measuring unit 7, the temperature measuring unit 8, and the control unit 9 is omitted as in FIG.

The high-temperature superconducting magnet device of the present embodiment replaces the high-temperature superconducting wire 21a of the second embodiment with the high-temperature superconducting wire 21b drawn from the superconducting switch 2 and the current feeder wire 11 as shown in FIGS. 6 and 7. In the connection portion with the second high-temperature superconducting wire 32 electrically connected, the heater 4b is thermally connected as a temperature control unit for changing the resistance.

Since the configuration of the second high-temperature superconducting wire 32 is the same as that of the high-temperature superconducting wire 21 shown in FIG. 3, the description thereof will be omitted. Further, although only the heater 4b is shown as the temperature control unit in FIG. 6, as in the first and second embodiments, in addition to other heating mechanisms, a heat transfer plate thermally connected to the refrigerator is used. It shall include a cooling mechanism.

(For use)
In the present embodiment configured as described above, a part of the connection path between the exciting power supply 5 and the superconducting switch 2 in which the heater 4b as a temperature control unit for changing the resistance is installed is drawn from the superconducting switch 2. It is a connection portion between the high-temperature superconducting wire 21b and the second high-temperature superconducting wire 32 electrically connected to the current feeder wire 11.

As a result, in the present embodiment, the heat capacity per unit length is larger than that in the second embodiment, but the resistance value is added to the resistance of the second high-temperature superconducting wire 32 and the connection resistance between the solder layers. The resistance per unit length can be made higher than in the second embodiment.

Since the operation control method of the present embodiment is the same as that of the first embodiment, the description thereof will be omitted.

(Effect)
According to this embodiment, the heat capacity per unit length is larger than that of the second embodiment, but the resistance per unit length can be higher than that of the second embodiment. Therefore, it is possible to provide a high-temperature superconducting magnet device capable of generating a resistance component higher than that of the high-temperature superconducting coil 1 in a space-saving manner.

The section in which the heater 4b is installed in the present embodiment is in the longitudinal direction of the high-temperature superconducting wire 21b and the second high-temperature superconducting wire 32 from the connection portion between the high-temperature superconducting wire 21b and the second high-temperature superconducting wire 32, respectively. It may be extended, or a plurality of heaters 4b may be divided and provided.

(Fourth Embodiment)
(Constitution)
FIG. 8 is an enlarged cross-sectional view showing a connection portion of the high-temperature superconducting magnet device showing the fourth embodiment. The same configurations as those in the first to third embodiments are designated by the same reference numerals, and redundant description will be omitted.

The high-temperature superconducting magnet device of the present embodiment includes a high-temperature superconducting wire 21a drawn from the superconducting switch 2 of the second embodiment, a high-temperature superconducting wire 21b drawn from the superconducting switch 2 of the third embodiment, and a current feeder wire 11. The configuration of the connection portion with the second high-temperature superconducting wire 32 electrically connected to is changed as follows.

As shown in FIG. 8, the high-temperature superconducting magnet device of the present embodiment is connected to both the high-temperature superconducting wire 21c drawn from the superconducting switch 2 and the second high-temperature superconducting wire 32 drawn from the current feeder wire 11. A heater 4c as a temperature control unit for changing the resistance is thermally connected to the third high-temperature superconducting wire 34.

Here, the third high-temperature superconducting wire 34 has a configuration different from that of the high-temperature superconducting wire used for the high-temperature superconducting coil 1 and the high-temperature superconducting wire 21c drawn from the superconducting switch 2. Specifically, the third high-temperature superconducting wire 34 has a configuration in which the stabilized copper of the stabilizing layer 27 is relatively thin or does not have the stabilized copper.

(For use)
In the present embodiment configured as described above, a part of the connection path between the exciting power source 5 and the superconducting switch 2 in which the heater 4c as a temperature control unit for changing the resistance is installed is drawn from the superconducting switch 2. It is a third high-temperature superconducting wire 34 connected to both the high-temperature superconducting wire 21c and the second high-temperature superconducting wire 32 drawn from the current feeder wire 11.

In the third high-temperature superconducting wire 34, the stabilized copper of the stabilizing layer 27 is relatively thinner than the high-temperature superconducting wire used for the high-temperature superconducting coil 1 and the high-temperature superconducting wire 21c drawn from the superconducting switch 2. Or a high-temperature superconducting wire that does not have stabilized copper. Therefore, the heat capacity per unit length can be further reduced as compared with the second embodiment and the third embodiment.

Since the operation control method of the present embodiment is the same as that of the first embodiment, the description thereof will be omitted.

(Effect)
According to the present embodiment, a part of the connection path between the exciting power supply 5 and the superconducting switch 2 in which the heater 4c as the temperature control unit for changing the resistance is installed is a part of the second embodiment to the third embodiment. The heat capacity per unit length can be further reduced. Therefore, it is possible to provide a high-temperature superconducting magnet device capable of generating a resistance component higher than that of the high-temperature superconducting coil 1 with a much smaller amount of heating and recovering in a shorter time.

The section in which the heater 4c is installed in the present embodiment may be extended in the longitudinal direction from the connection portion between the high-temperature superconducting wire 21c, the second high-temperature superconducting wire 32, and the third high-temperature superconducting wire 34. Alternatively, a plurality of heaters 4c may be divided and provided.

(Other embodiments)
Although each embodiment of the present invention has been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, changes, and combinations can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

In the circuit diagram in the description of the first to fourth embodiments, the high-temperature superconducting coil 1 is shown by one inductance and one resistance component, but a plurality of high-temperature superconducting coils 1 are electrically connected in series or in parallel. It can also be applied to high-temperature superconducting coils that are specifically connected. In that case, it is possible to provide a plurality of temperature control units for turning on, off, and changing the resistance of the superconducting switch 2.

1 ... High-temperature superconducting coil, 2 ... Superconducting switch, 3 ... Heater, 4, 4a, 4b, 4c ... Heater (temperature control unit), 5 ... Exciting power supply, 6 ... Solder layer, 7 ... Magnetic current measuring unit, 8 ... Temperature measurement Unit, 9 ... Control unit, 11 ... Current feeder wire, 12a, 12b ... Connection unit, 13a, 13b ... Connection unit, 21,21a, 21b, 21c ... High-temperature superconducting wire, 24 ... Tape substrate, 25 ... Intermediate layer, 26 ... Superconducting layer, 27 ... Stabilizing layer, 28 ... Alignment layer, 29 ... Protective layer, 32 ... Second high-temperature superconducting wire, 34 ... Third high-temperature superconducting wire.

Claims (9)

High-temperature superconducting coil and
An exciting power supply connected to the high-temperature superconducting coil to supply current,
A superconducting switch connected to the exciting power source and electrically connected in parallel with the high-temperature superconducting coil is provided.
A high-temperature superconducting magnet device characterized in that a temperature control unit is provided in a section having a heat capacity smaller than that of the superconducting switch in a connection path between the exciting power supply and the superconducting switch. The temperature control unit is characterized by including a heating mechanism by a heater thermally connected to a section having a heat capacity smaller than that of the superconducting switch, and a cooling mechanism by a heat transfer plate thermally connected to the refrigerator. The high-temperature superconducting magnet device according to claim 1. The section of the connection path provided with the temperature control unit is a connection portion between the high-temperature superconducting wire drawn from the superconducting switch and the current feeder wire made of normal conductive metal drawn from the exciting power source. The high-temperature superconducting magnet device according to claim 1 or 2. The high-temperature superconducting magnet device according to claim 1 or 2, wherein the section of the connection path provided with the temperature control unit is a high-temperature superconducting wire drawn from the superconducting switch. The section of the connection path provided with the temperature control unit was electrically connected to a high-temperature superconducting wire drawn from the superconducting switch and a current feeder wire made of a normal conducting metal drawn from the exciting power source. The high-temperature superconducting magnet device according to claim 1 or 2, wherein the high-temperature superconducting magnet device is a connection portion with a second high-temperature superconducting wire. The section of the connection path provided with the temperature control unit is the first drawn from the high-temperature superconducting wire drawn from the superconducting switch and the current feeder wire made of a normal-conducting metal drawn from the exciting power source. The high-temperature superconducting magnet device according to claim 5, wherein the high-temperature superconducting magnet device is provided on a third high-temperature superconducting wire connected to both high-temperature superconducting wires of the second high-temperature superconducting wire. The third high-temperature superconducting wire is characterized in that the stabilized copper is relatively thinner than the high-temperature superconducting wire connected to the high-temperature superconducting coil and the superconducting switch, or has no stabilized copper. 6. The high-temperature superconducting magnet device according to 6. It includes a high-temperature superconducting coil, an exciting power source connected to the high-temperature superconducting coil to supply an electric current, and a superconducting switch connected to the exciting power source and electrically connected in parallel with the high-temperature superconducting coil. An operation control device for a high-temperature superconducting magnet device that controls the operation of a high-temperature superconducting magnet device provided with a temperature control unit in a section having a smaller heat capacity than the superconducting switch in the connection path between the power supply and the superconducting switch.
A magnetic field measuring unit that measures the generated magnetic field of the high-temperature superconducting coil,
A temperature measuring unit that measures the temperature corresponding to the resistance value of the section of the connection path provided with the temperature control unit, and a temperature measuring unit.
When the generated magnetic field approaches the magnetic field corresponding to the lower limit of the rated current value, the resistance value in the section of the connection path provided with the temperature control unit becomes higher than the resistance value of the high temperature superconducting coil. A control unit that controls to increase the value,
An operation control device for a high-temperature superconducting magnet device. It includes a high-temperature superconducting coil, an exciting power source connected to the high-temperature superconducting coil to supply an electric current, and a superconducting switch connected to the exciting power source and electrically connected in parallel with the high-temperature superconducting coil. A method for controlling the operation of a high-temperature superconducting magnet device that controls the operation of a high-temperature superconducting magnet device provided with a temperature control unit in a section having a smaller heat capacity than the superconducting switch in the connection path between the power supply and the superconducting switch.
A magnetic field measurement step for measuring the generated magnetic field of the high-temperature superconducting coil, and
A temperature measurement step of measuring a temperature corresponding to a resistance value in a section of the connection path provided with the temperature control unit, and a temperature measurement step.
When the generated magnetic field approaches the magnetic field corresponding to the lower limit of the rated current value, the resistance value in the section of the connection path provided with the temperature control unit becomes higher than the resistance value of the high temperature superconducting coil. A control process that controls to increase the value,
A method for controlling the operation of a high-temperature superconducting magnet device.

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