JP2020068293A - Superconducting magnet device - Google Patents

Abstract

To make it possible to secure soundness of a superconducting coil when abnormality occurs in the superconducting coil at a stationary time of supplying rated current from an excitation power supply and emergent cutoff of the current supply is performed.SOLUTION: A superconducting magnet device includes: a high-temperature superconducting coil 13 configured using a high-temperature superconducting wire; an excitation power supply 16 for supplying current to the high-temperature superconducting coil; a permanent current switch 14 that is electrically connected in parallel to the high-temperature superconducting coil, forms a closed loop 23 together with the high-temperature superconducting coil, and is configured using a high-temperature superconducting material; a minute resistance body 15 individually electrically connected in series to the permanent current switch and in parallel to the high-temperature superconducting coil; and a protective resistor 17 that is electrically connected in parallel to the excitation power supply 16 and has a resistance value set higher than that of the minute resistance body 15 and smaller than that of the permanent current switch 14 in a normal conducting state. The minute resistance body 15 is thermally connected to the permanent current switch 14.SELECTED DRAWING: Figure 1

Description

  The embodiment of the present invention relates to a superconducting magnet device in which a persistent current switch and a minute resistor are electrically connected in parallel to a superconducting coil.

  With the development of high-temperature superconducting wires, superconducting devices are being replaced with devices using conventional metal-based superconducting wires by devices using high-temperature superconducting wires. Further, the superconducting devices include devices such as a magnetic resonance imaging apparatus (MRI) and a nuclear magnetic resonance measuring apparatus (NMR) that require a uniform magnetic field and temporal stability of the magnetic field. In such a device, for example, a permanent current switch is used to switch to the permanent current mode, whereby a stable magnetic field can be generated in the high temperature superconducting coil regardless of the temporal stability of the power supply.

  In the high-temperature superconducting wire that constitutes the high-temperature superconducting coil, the electric resistance of the wire itself becomes zero (0), but at the present time, there is a minute resistance at the place where the wire is connected, and even in the permanent current mode, the energizing current is Finite damping occurs. Therefore, it is necessary to generate the magnetic field in the power supply mode in order to reduce the temporal change of the magnetic field generated by the high temperature superconducting coil. In that case, the temporal stability of the current output from the power supply itself directly affects the temporal stability of the generated magnetic field, and therefore the power supply needs to have stability with little temporal fluctuation in the output current.

  As one of the methods to make it difficult to convey the temporal fluctuation of the output current of the power supply to the energizing current flowing through the superconducting coil, a circuit (described later) is installed in parallel with the superconducting coil to shunt the output current of the power supply. A configuration is known in which a time variation of current is compensated (suppressed) by a parallel circuit. FIG. 8 shows a conventional high temperature superconducting magnet device 100 provided with this parallel circuit.

  In this high temperature superconducting magnet device 100, an exciting power supply 102 is electrically connected to a high temperature superconducting coil 101 made of a high temperature superconducting wire, and a persistent current switch 103 and a micro resistor 104 are electrically parallel to the high temperature superconducting coil 101. The protective resistance 105 is electrically connected in parallel to the excitation power source 102, and the permanent current switch 103 and the minute resistor 104 are electrically connected in series. The persistent current switch 103 is made of a high-temperature superconducting material, and a temperature raising heater 106 that raises the temperature of the persistent current switch 103 is thermally connected to the persistent current switch 103.

  The high temperature superconducting coil 101, the permanent current switch 103, the minute resistor 104, and the temperature raising heater 106 are arranged in a radiation shield 108 provided in a vacuum container 107, and cooled by a refrigerator 109 to a level below 20K. Further, the excitation power supply 102 and the protection resistor 105 are installed in a room temperature region outside the vacuum container 107. The high temperature superconducting coil 101 has a resistance component 110 due to a connection resistance or the like.

  The micro-resistor 104 has a resistance value such that the steady-state current is supplied to the high-temperature superconducting coil 101 from the exciting power supply 102, and the steady-state current has a current value desired to be shunted to itself (the micro-resistor 104). Is set. By shunting the current from the excitation power source 102 to the minute resistor 104 in a steady state, the temporal variation of the current output from the excitation power source 102 is absorbed by the minute resistor 104, and the current value is supplied to the high temperature superconducting coil 101. A constant current flows.

  Immediately after the circuit breaker 111 is cut off and the exciting power supply 102 is cut off in a steady state, the permanent power switch 103 is below the critical temperature and is in the superconducting state (ON). Therefore, most of the current flowing through the high temperature superconducting coil 101 is The current flows not to the protective resistance 105 but to the minute resistor 104 and the persistent current switch 103, and then flows to the closed loop 112 formed by the high temperature superconducting coil 101 (including the resistance component 110), the minute resistor 104 and the persistent current switch 103.

  On the other hand, immediately after the circuit breaker 111 shuts off the excitation power supply 102, the temperature raising heater 106 raises the temperature of the permanent current switch 103 to bring the permanent current switch 103 into the normal conduction state (OFF) above the critical temperature, The current flowing through the high temperature superconducting coil 101 is guided to the protective resistor 105. As a result, the magnetic energy of the high temperature superconducting coil 101 is consumed by the protective resistor 105, the current flowing through the high temperature superconducting coil 101 is attenuated, and as a result, burning or deterioration of the high temperature superconducting coil 101 is prevented.

JP, 2008-41966, A JP, 2005-259826, A JP, 2004-179413, A

  By the way, when the exciting power supply 102 is shut off by the circuit breaker 111 in an emergency, the heater power supply 113 supplies a current to the temperature raising heater 106 until the permanent current switch 103 is switched to the normal conduction state (OFF) by the temperature raising heater 106. The time is determined by the maximum heating amount of the temperature raising heater 106, the heat capacity of the permanent current switch 103, the heat transfer characteristic between the temperature raising heater 106 and the permanent current switch 103, and the like.

  However, at the time of emergency shutoff of the exciting power supply 102 by the circuit breaker 111 in a steady state, if the time until the permanent current switch 103 shifts to the normal conduction state (OFF) becomes long, the current flowing through the high temperature superconducting coil 101 flows through the closed loop 112. Since the operation is continued, there is a risk that the current will continue to flow to the location where the abnormality has occurred in the high temperature superconducting coil 101, and the high temperature superconducting coil 101 will be burned or deteriorated.

  In addition, even if the temperature raising heater 106 fails and cannot be used, the current flowing through the high temperature superconducting coil 101 will continue to flow through the closed loop 112 when the exciting power supply 102 is emergency shut off by the circuit breaker 111. The coil 101 may be burned or deteriorated. If a backup heater is provided for the temperature raising heater 106 in order to avoid this, the device configuration of the high temperature superconducting magnet device 100 becomes complicated.

  The embodiment of the present invention has been made in consideration of the above circumstances, and when an abnormality occurs in the superconducting coil during a steady state in which the rated current is supplied from the excitation power source to the superconducting coil and the current supply is cut off urgently. An object of the present invention is to provide a superconducting magnet device capable of consuming the magnetic energy of the superconducting coil at an early stage and ensuring the soundness of the superconducting coil.

  Another embodiment of the present invention is to provide a superconducting magnet device capable of stabilizing the magnetic field formed by the superconducting coil for a long period of time.

  The superconducting magnet device in the embodiment of the present invention is composed of a superconducting wire, a superconducting coil that forms a magnetic field by supplying an electric current, an exciting power supply that supplies a current to the superconducting coil to excite the superconducting coil, and A superconducting coil is electrically connected in parallel to form a closed loop together with the superconducting coil, and a permanent current switch made of a superconducting material is electrically connected in series to the permanent current switch and in parallel to the superconducting coil. A minute resistor that is connected and determines a shunt ratio that divides the current from the excitation power source into the superconducting coil and the permanent current switch, and is electrically connected in parallel to the excitation power source and has a resistance value of the minute resistor. The magnetic energy of the superconducting coil can be consumed by being set larger than the body and smaller than the permanent current switch in the normal conduction state. Mamoru and resistance, a superconducting magnet apparatus having the micro-resistor is characterized in that it has been configured is thermally connected to the permanent current switch.

  Further, the superconducting magnet device in the embodiment of the present invention is composed of a superconducting wire, a superconducting coil that forms a magnetic field by supplying an electric current, and an exciting power supply that supplies a current to the superconducting coil to excite the superconducting coil. , Electrically connected in parallel to the superconducting coil to form a closed loop together with the superconducting coil, and a permanent current switch made of the superconducting wire, in series with the permanent current switch and in parallel with the superconducting coil, respectively. A minute resistor that is electrically connected and that determines a shunt ratio that divides the current from the excitation power supply into the superconducting coil and the permanent current switch, and is electrically connected in parallel to the excitation power supply and has a resistance value of The magnetic energy of the superconducting coil is set to be larger than the minute resistor and smaller than the permanent current switch in the normal conduction state. A superconducting magnet device having a consumable protection resistor, comprising a magnetic field sensor for detecting a magnetic field formed by a superconducting coil, wherein the minute resistor or the protection resistor is a current flowing from the exciting power source to the superconducting coil. The resistance value can be adjusted based on the detection value of the magnetic field sensor so that the current value of 1 becomes constant.

  According to the embodiment of the present invention, the magnetic energy of the superconducting coil is consumed early when an abnormality occurs in the superconducting coil during the steady state in which the rated current is supplied from the exciting power source to the superconducting coil and the current supply is cut off urgently. The soundness of the superconducting coil can be secured. Further, according to the embodiment of the present invention, the magnetic field formed by the superconducting coil can be stabilized for a long period of time.

The electric circuit diagram which shows the high temperature superconducting magnet apparatus to which the superconducting magnet apparatus concerning 1st Embodiment was applied. The electric circuit diagram which shows the high temperature superconducting magnet apparatus to which the superconducting magnet apparatus concerning 2nd Embodiment was applied. The perspective view which shows the permanent current switch of the high temperature superconducting magnet apparatus to which the superconducting magnet apparatus concerning 3rd Embodiment was applied. The permanent-current switch of the high temperature superconducting magnet apparatus to which the superconducting magnet apparatus concerning 4th Embodiment is applied is shown, (A) is the perspective view, (B) is a perspective view of the high temperature superconducting tape wire rod etc. before being bundled and wound. . The permanent-current switch and the microresistor of the high temperature superconducting magnet apparatus to which the superconducting magnet apparatus according to the fifth embodiment is applied are shown, (A) is a perspective view thereof, and (B) is a high temperature superconducting tape wire before being bundled and wound. And a perspective view of the normal conductive metal tape wire, etc., (C) a cross-sectional view of the high temperature superconducting tape wire, etc., (D) a cross-sectional view of the normal metal tape wire. The electric circuit diagram which shows the high temperature superconducting magnet apparatus to which the superconducting magnet apparatus concerning 6th Embodiment was applied. The electric circuit diagram which shows the modification of the high temperature superconducting magnet apparatus of FIG. The electric circuit diagram which shows the conventional high temperature superconducting magnet apparatus.

Hereinafter, modes for carrying out the present invention will be described with reference to the drawings.
[A] First Embodiment (FIG. 1)
FIG. 1 is an electric circuit diagram showing a high temperature superconducting magnet device to which the superconducting magnet device according to the first embodiment is applied. A high temperature superconducting magnet device 10 as a superconducting magnet device shown in FIG. 1 includes a vacuum container 11 which is an adiabatic vacuum tank, and a high temperature superconducting coil which is a superconducting coil arranged in a radiation shield 12 provided in the vacuum container 11. The coil 13, the permanent current switch 14 and the minute resistor 15, the excitation power supply 16 and the protection resistor 17 installed in the room temperature region outside the vacuum container 11, and the refrigerator 18 installed in the vacuum container 11 are provided. Composed.

  The refrigerator 18 cools the radiation shield 12 to, for example, a level of 50K by the first cooling stage 18A, and the high temperature superconducting coil 13 by the second cooling stage 18B via the heat transfer plate 19 and the heat transfer plates 19 and 20. Each of the permanent current switches 14 is cooled to, for example, a level of 20 K or less via the above. Here, the heat transfer plate 19 is made of a metal having a high thermal conductivity. The heat transfer plate 20 is made of a metal having a higher thermal resistance than the heat transfer plate 19. The heat resistance of the heat transfer plate 20 is such that the heat inflow amount from the permanent current switch 14 to the high temperature superconducting coil 13 becomes small when the temperature of the permanent current switch 14 rises, and the refrigerating machine 18 makes the permanent current switch 14 cool again. The optimum value is set so that the recooling time becomes short.

The excitation power supply 16 is connected to the high temperature superconducting coil 13 via a current lead 21, and supplies a current to the high temperature superconducting coil 13 to excite the high temperature superconducting coil 13. The high-temperature superconducting coil 13 is made of a high-temperature superconducting wire and forms a magnetic field by supplying an electric current from the exciting power supply 16. Examples of the high-temperature superconducting wire include Bi ₂ Sr ₂ Ca ₂ Cu ₃ O ₁₀ wire and REBaCuO ₇ wire. Further, in the high temperature superconducting coil 13, an electric resistance due to the connection resistance of the high temperature superconducting wire or the like exists as a resistance component 22.

  The persistent current switch 14 is electrically connected to the high temperature superconducting coil 13 in parallel, and forms a closed loop 23 together with the high temperature superconducting coil 13 and the minute resistor 15 (detailed later). The permanent current switch 14 is made of a high temperature superconducting material, preferably a high temperature superconducting wire similar to the high temperature superconducting coil 13.

  A heating heater 24 is electrically connected to the permanent current switch 14 although it is electrically insulated. The heating heater 24 is independently turned on by supplying a current from a heater power supply 26 electrically connected through a current lead 25, heats the permanent current switch 14 and raises the temperature above a critical temperature. Let it warm. As a result, the persistent current switch 14 shifts from the superconducting state (ON) to the normal conducting state (OFF). Here, the temperature raising heater 24 is arranged inside the radiation shield 12, and the heater power supply 26 is arranged outside the vacuum container 11 in a room temperature region.

  The minute resistor 15 is electrically connected in series to the persistent current switch 14 and electrically connected in parallel to the high temperature superconducting coil 13. The minute resistor 15 is a shunt that divides the current output from the exciting power source 16 into the high temperature superconducting coil 13 side and the permanent current switch 14 side during a steady state when the rated current is supplied from the exciting power source 16 to the high temperature superconducting coil 13. Determine the ratio. That is, the minute resistor 15 is set to have a resistance value that is a current value desired to be shunted to itself (the minute resistor 15) in a steady state and larger than the resistance component 22 of the high temperature superconducting coil 13. When the current output from the excitation power supply 16 is shunted to the minute resistor 15 in a steady state and flows, the minute resistor 15 absorbs the variation even if the current output from the excitation power source 16 changes with time. Then, the current value of the current flowing through the high temperature superconducting coil 13 is made constant.

  The protection resistor 17 is electrically connected in parallel to the excitation power supply 16 and a circuit breaker 27 electrically connected in series to the excitation power supply 16. The resistance value of the protection resistor 17 is set to be larger than the resistance value of the minute resistor 15 and smaller than the resistance value of the permanent current switch 14 in the normal conduction state (OFF). As a result, when the high-temperature superconducting coil 13 is abnormally generated in a steady state and the circuit breaker 27 urgently cuts off the excitation power supply 16, when the permanent current switch 14 is in the normal conduction state (OFF), The current flowing through the superconducting coil 13 is guided to the protective resistor 17, and the protective resistor 17 consumes the magnetic energy of the high temperature superconducting coil 13. The circuit breaker 27 is arranged outside the vacuum container 11 in a room temperature region. Reference numeral 28 in FIG. 1 indicates a thermal anchor.

  By the way, in the first embodiment, the minute resistor 15 is electrically connected to the permanent current switch 14 in series, and is thermally connected to the permanent current switch 14 so that a current flows to the minute resistor 15. The heat generated when flowing is transferred to the permanent current switch 14. That is, when the exciting power supply 16 is shut off by the circuit breaker 27 in an emergency, the permanent current switch 14 is still in the superconducting state (ON), so that the current flowing through the high temperature superconducting coil 13 flows through the closed loop 23. Since the current flowing through the high temperature superconducting coil 13 is close to the rated current, it flows through the minute resistor 15 in the closed loop 23, so that the minute resistor 15 generates heat. Then, the heat of the minute resistor 15 is transferred to the permanent current switch 14, so that the permanent current switch 14 can be moved from the superconducting state (ON) to the normal conducting state (OFF) early and quickly. become.

Next, the operation of the high temperature superconducting magnet device 10 will be described.
When the high temperature superconducting coil 13 is excited, the temperature raising heater 24 is turned on, and the permanent current switch 14 is heated and is in the normal conduction state (OFF). In this state, the current from the exciting power supply 16 does not shunt to the permanent current switch 14 side but flows only to the high temperature superconducting coil 13, and the high temperature superconducting coil 13 forms a magnetic field.

  During a steady state in which the rated current is supplied to the high temperature superconducting coil 13, the temperature raising heater 24 is turned off and the permanent current switch 14 is in the superconducting state (ON). In this state, the current from the excitation power source 16 is supplied to the high temperature superconducting coil 13 (including the resistance component 22), the persistent current switch 14 and the minute resistor 15 according to the shunt ratio determined by the resistance value of the minute resistor 15. It splits and flows. As a result, a current having a constant current value flows through the high temperature superconducting coil 13, and the high temperature superconducting coil 13 forms a stable magnetic field.

  When an abnormality occurs in the high temperature superconducting coil 13 in a steady state and the circuit breaker 27 urgently cuts off the exciting power source 16, the temperature raising heater 24 is turned on and the permanent current switch 14 is heated. However, until the permanent current switch 14 is heated to the normal conduction state (OFF), the current flowing through the high temperature superconducting coil 13 (current close to the rated current value) is the superconducting state (ON) persistent current switch. Since the resistance value of 14 is smaller than that of the protective resistance 17, the current flows through the closed loop 23 including the high temperature superconducting coil 13 (including the resistance component 22), the persistent current switch 14 and the minute resistor 15.

  At this time, since the heat generated by the minute resistor 15 of the closed loop 23 heats the permanent current switch 14, it is possible to shorten the time until the permanent current switch 14 shifts to the normal conduction state (OFF). As a result, in combination with the heating by the temperature raising heater 24, the permanent current switch 14 quickly becomes the normal conduction state (OFF) when the exciting power source 16 is emergency cut off by the circuit breaker 27, and the current flowing through the high temperature superconducting coil 13 is reduced. It flows to the protection resistor 17 early. The protection resistor 17 consumes the magnetic energy of the permanent current switch 14, and the current flowing through the high temperature superconducting coil 13 is attenuated.

With the above configuration, according to the first embodiment, the following effects (1) and (2) are obtained.
(1) When the high-temperature superconducting coil 13 has an abnormality during the steady state in which the rated current is supplied from the exciting power source 16 to the high-temperature superconducting coil 13 and the exciting power source 16 is urgently shut off, the superconducting state is still below the critical temperature (ON). A current having a current value close to the rated current flows through the minute resistor 15 electrically connected in series with the permanent current switch 14 at, and the temperature of the minute resistor 15 rapidly rises to generate heat. At this time, since the minute resistor 15 is thermally connected to the permanent current switch 14, the heat generated by the minute resistor 15 is transferred to the permanent current switch 14, and the temperature of the permanent current switch 14 is raised early. In combination with the heating by the temperature raising heater 24, the temperature rises above the critical temperature in a short time to enter the normal conduction state (OFF).

  Since the resistance value of the permanent current switch 14 in the normal conduction state is set to be larger than that of the protection resistor 17, the current flowing through the high temperature superconducting coil 13 quickly flows to the protection resistor 17, and the protection resistor 17 causes the high temperature superconducting The magnetic energy of the coil 13 is consumed early and the current is attenuated. As a result, burning and deterioration of the high temperature superconducting coil 13 can be reliably prevented, and the soundness of the high temperature superconducting coil 13 can be secured.

  (2) Since the minute resistor 15 is thermally connected to the permanent current switch 14 and the temperature of the permanent current switch 14 is raised by the minute resistor 15, the temperature raising heater 24 for raising the temperature of the permanent current switch 14 is A failure can be dealt with, a backup heater is not required, and the configuration of the permanent current switch 14 can be simplified.

(B) Second embodiment (FIG. 2)
FIG. 2 is an electric circuit diagram showing a high temperature superconducting magnet device to which the superconducting magnet device according to the second embodiment is applied. In the second embodiment, the same parts as those in the first embodiment are designated by the same reference numerals as those in the first embodiment to simplify or omit the description.

  The high-temperature superconducting magnet device 30 as the superconducting magnet device in the second embodiment is different from that of the first embodiment in that the temperature raising heater 24 that raises the temperature of the permanent current switch 14 and current is supplied to the temperature raising heater 24. The current lead 25 and the heater power supply 26 are omitted, and the temperature of the permanent current switch 14 is raised only by the minute resistor 15.

  When the high temperature superconducting coil 13 in the high temperature superconducting magnet device 30 is excited, the current supplied to the high temperature superconducting coil 13 gradually increases, so that an induction voltage is generated by the inductance of the high temperature superconducting coil 13. Therefore, the voltage across the high-temperature superconducting coil 13 including the resistance component 22 increases, and a large current flows through the minute resistor 15 to heat the minute resistor 15. The permanent current switch 14 is heated to the normal conduction state (OFF) due to the heat generated by the minute resistor 15, and the current from the exciting power supply 16 is not shunted to the permanent current switch 14 side, but the high temperature superconducting coil 13 is shunted. Flowing in only the high temperature superconducting coil 13 forms a magnetic field.

  During a steady state in which the rated current flows through the high temperature superconducting coil 13, no induced voltage is generated in the high temperature superconducting coil 13, and the permanent current switch 14 is in the superconducting state (ON). Therefore, the current from the excitation power supply 16 is shunted to the high temperature superconducting coil 13 (including the resistance component 22), the persistent current switch 14 and the micro resistor 15 according to the shunt ratio determined by the resistance value of the micro resistor 15. Flowing. As a result, a current having a constant current value flows through the high temperature superconducting coil 13, and the high temperature superconducting coil 13 forms a stable magnetic field.

  When an abnormality occurs in the high-temperature superconducting coil 13 in a steady state and the breaker 27 urgently cuts off the exciting power supply 16, the current flowing through the high-temperature superconducting coil 13 has a resistance value of the minute resistor 15 smaller than that of the protective resistor 17. Therefore, the current flows in the closed loop 23 including the permanent current switch 14 and the minute resistor 15. At this time, since a large current close to the rated current flows through the minute resistor 15, the minute resistor 15 generates heat to raise the temperature of the permanent current switch 14, and the permanent current switch 14 is in the normal conduction state ( OFF). As a result, the current flowing through the high temperature superconducting coil 13 flows to the protective resistor 17, the protective resistor 17 consumes the magnetic energy of the high temperature superconducting coil 13, and the current flowing through the high temperature superconducting coil 13 is attenuated.

  As described above, also in the second embodiment, the following effect (3) similar to the effect (1) of the first embodiment is achieved, and also the effect (4) is achieved.

  (3) The minute resistor 15 is thermally connected to the permanent current switch 14, and when the circuit breaker 27 shuts off the excitation power supply 16 in an emergency, the heat generated by the minute resistor 15 causes the permanent current switch 14 to rise in temperature early and is normally conducted. In the state (OFF), the current flowing through the high temperature superconducting coil 13 is quickly guided to the protection resistor 17 and attenuated. As a result, burning and deterioration of the high temperature superconducting coil 13 can be prevented, and the soundness of the high temperature superconducting coil 13 can be secured.

  (4) According to the second embodiment, as compared with the first embodiment, the temperature raising heater 24, the current lead 25, and the heater power supply 26 are omitted, so that the configuration of the permanent current switch 14 can be simplified, It is possible to improve the ease of handling the high temperature superconducting magnet device 30.

[C] Third embodiment (FIG. 3)
FIG. 3 is a perspective view showing a permanent current switch of a high temperature superconducting magnet device to which the superconducting magnet device according to the third embodiment is applied. In the third embodiment, the same parts as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment to simplify or omit the description.

  The high temperature superconducting magnet device 33 as the superconducting magnet device of the third embodiment is different from the first embodiment in that the permanent current switch 34 of the high temperature superconducting magnet device 33 winds a tape-shaped high temperature superconducting tape wire 35. The high-temperature superconducting pancake coil 36 is formed, and an even number of the high-temperature superconducting pancake coils 36 are laminated to form a non-inductive coil.

  When two high temperature superconducting pancake coils 36 are stacked as shown in FIG. 3, the end of each high temperature superconducting tape wire 35 is electrically connected to the inner end of the high temperature superconducting tape wire 35 by the connecting plate 37. Connected. Further, by stacking an even number of high-temperature superconducting pancake coils 36, when a current flows through the high-temperature superconducting tape wire material 35 of each high-temperature superconducting pancake coil 36, the high-temperature superconducting pancake coils 36 respectively generate a pair. The magnetic field B reverses and cancels out, and the permanent current switch 34 becomes a non-inductive coil in which no induced voltage is generated.

With the configuration described above, the persistent current switch 34 of the third embodiment has the following effects (5) and (6).
(5) Since the permanent current switch 34 is configured by the high temperature superconducting pancake coil 36 formed by winding the high temperature superconducting tape wire 35, the length of the high temperature superconducting tape wire 35 can be freely set. Therefore, since the resistance value of the permanent current switch 34 when the permanent current switch 34 is in the normal conduction state (OFF) can be freely set, the permanent current switch 34 is designed by being adapted to the high temperature superconducting coil 13 of various specifications. can do.

  (6) Since the permanent current switch 34 is configured as a non-inductive coil by stacking an even number of high-temperature superconducting pancake coils 36, the induced voltage remains unchanged even when the current value flowing through the permanent current switch 34 is changed. Does not occur. Therefore, the operation in which the permanent current switch 34 is in the superconducting state (ON) and the operation in which it is in the normal conduction state (OFF) can be switched in a short time. Further, since the permanent current switch 34 is configured as a non-inductive coil, the permanent current switch 34 is protected from the magnetic field generated in the high temperature superconducting coil 13 even when it is installed in a position close to the high temperature superconducting coil 13. You can offset the force you receive.

[D] Fourth embodiment (FIG. 4)
FIG. 4 shows a permanent current switch of a high-temperature superconducting magnet device to which the superconducting magnet device according to the fourth embodiment is applied. (A) is a perspective view thereof, and (B) is a high-temperature superconducting tape wire rod before being bundled and wound. FIG. In the fourth embodiment, the same parts as those in the first embodiment are designated by the same reference numerals as those in the first embodiment to simplify or omit the description.

  The high-temperature superconducting magnet device 40 as the superconducting magnet device of the fourth embodiment is different from the first embodiment in that the permanent current switch 41 of the high-temperature superconducting magnet device 40 has two tape-shaped high-temperature superconducting tape wires (inner side). The point is that the high temperature superconducting tape wire 42 and the outer high temperature superconducting tape wire 43) are connected at one end, bundled with an insulating tape 44 interposed therebetween, and wound together to form a high temperature superconducting pancake coil 45.

  That is, as shown in FIG. 4B, one end of each of the inner high temperature superconducting tape wire 42 and the outer high temperature superconducting tape wire 43 is connected to form a connecting end 46, and the connecting end 46 is placed inside and insulated. The tape 44 is interposed, and the bundles are bundled and simultaneously wound in a pancake shape to form a high-temperature superconducting pancake coil 45 shown in FIG. 4 (A), and the high-temperature superconducting pancake coil 45 is configured as a permanent current switch 41.

  In this high-temperature superconducting pancake coil (permanent current switch 41), the outer ends of the inner high-temperature superconducting tape wire 42 and the outer high-temperature superconducting tape wire 43, which are opposite to the connecting ends 46, are electrodes 47, 48. The high-temperature superconducting pancake coil 45 (permanent current switch 41) is configured as a non-induction coil because the current I flows in the opposite direction to the inner high-temperature superconducting tape wire 42 and the outer high-temperature superconducting tape wire 43.

  With the configuration as described above, according to the persistent current switch 41 of the fourth embodiment, in addition to the same effects as the effects (5) and (6) of the third embodiment, the following effect (7) is obtained. ) Is played.

  (7) Since the persistent current switch 41 is composed of one layer of high-temperature superconducting pancake coil 45, the configuration can be simplified and compared to the case where the persistent current switch 41 is composed of a plurality of layers of high-temperature superconducting pancake coil. Thus, the temperature control by the minute resistor 15 or the temperature raising heater 24 can be facilitated. That is, when the permanent current switch 41 is composed of one layer of the high temperature superconducting pancake coil 45, the inner high temperature superconducting tape wire 42 and the outer high temperature superconducting tape wire 43 which form the high temperature superconducting pancake coil 45 have a small resistance. It can be heated uniformly by the body 15 or the temperature raising heater 24. Therefore, the nonuniformity of the temperature of the inner high temperature superconducting tape wire 42 and the outer high temperature superconducting tape wire 43 is suppressed, and the temperature of the high temperature superconducting pancake coil 45 (permanent current switch 41) can be easily controlled.

[E] Fifth embodiment (FIG. 5)
FIG. 5 shows a permanent current switch and a minute resistor of a high temperature superconducting magnet device to which the superconducting magnet device according to the fifth embodiment is applied. (A) is a perspective view thereof, and (B) is before being bundled and wound. FIG. 2 is a perspective view of a high-temperature superconducting tape wire rod, a normal-conducting metal tape wire rod, and the like, FIG. 6C is a cross-sectional view of the high-temperature superconducting tape wire rod, and FIG. In the fifth embodiment, the same parts as those in the first embodiment are designated by the same reference numerals as those in the first embodiment to simplify or omit the description.

  The high-temperature superconducting magnet device 50 as the superconducting magnet device of the fifth embodiment is different from that of the first embodiment in that the persistent current switch 51 of the high-temperature superconducting magnet device 50 has a minute resistor having the function of the minute resistor 15. This is a point integrated with 52.

  That is, the permanent current switch 51 and the minute resistor 52 are pancakes in which a tape-shaped high-temperature superconducting tape wire 53 and a tape-shaped normal-conducting metal tape wire 54 are bundled together with an insulating tape 55 interposed therebetween and rolled together. The coil 56 is composed of the high-temperature superconducting tape wire 53 as the permanent current switch 51 and the normal-conducting metal tape wire 54 as the minute resistor 52.

  Specifically, as shown in FIG. 5 (B), the high-temperature superconducting tape wire rod 53 and the normal-conducting metal tape wire rod 54 are connected to each other at one end to form a connecting end 57, and the connecting end 57 is placed inside. In addition, the insulating tape 55 is interposed, and they are bundled and simultaneously wound in a pancake shape to form a pancake coil 56 shown in FIG. One end on the outside of the high-temperature superconducting tape wire 53 and the normal-conducting metal tape wire 54 (that is, the end on the outside of the high-temperature superconducting tape wire 53) becomes the electrode 58 of the permanent current switch 51, and the high-temperature superconducting tape wire 53 and the normal-conducting tape wire 53. The other outer end of the conductive metal tape wire 54 (that is, the outer end of the normal conductive metal tape wire 54) becomes the end 59 of the minute resistor 52.

  Further, the permanent current switch 51 is configured as a non-inductive coil because the current I flows in the opposite direction to the high temperature superconducting tape wire rod 53 and the normal conducting metal tape wire rod 54.

  The high-temperature superconducting tape wire 53 that constitutes the persistent current switch 51 is attached to a base material 60 as shown in FIG. 5C, and is covered with a protective layer 61 together with the base material 60. At least one of the material of the protective layer 61 (for example, silver (Ag) or copper (Cu)) and the thickness T of the protective layer 61 is changed so that the resistance value of the permanent current switch 51 in the normal conduction state (OFF) is changed. It is adjusted by As shown in FIG. 5D, the resistance value of the minute resistor 52 is determined by the material of the normal conductive metal tape wire 54 (for example, copper (Cu) or stainless steel), the purity of the material, and the normal conductive metal. It is adjusted by changing at least one of the thickness U of the tape wire rod 54 and the length of the normal conductive metal tape wire rod 54.

  With the above configuration, according to the fifth embodiment, the same effects as the effects (5), (6), and (7) of the third and fourth embodiments are achieved, and the following effects are also provided. Play (8) and (9).

  (8) Since the normal-conducting metal tape wire 54 that constitutes the minute resistor 52 is in surface contact with the high-temperature superconducting tape wire 53 that constitutes the permanent current switch 51 with the insulating tape 55 interposed, the minute resistor 52 is formed. When the above functions as a heater, the normal conductive metal tape wire 54 can uniformly raise the temperature of the high temperature superconducting tape wire 53 over the entire length. Therefore, the configurations of the persistent current switch 51 and the minute resistor 52 can be simplified, the heat capacity of the persistent current switch 51 can be reduced, and the operation in which the persistent current switch 51 is in the superconducting state (ON) and the normal conducting state (OFF). Can be switched in a short time.

  (9) Since the resistance value of the permanent current switch 51 in the normal conduction state (OFF) is adjustable, and further, the resistance value of the minute resistor 52 is adjustable, various types, sizes, and magnetic fields can be obtained. It is possible to design the persistent current switch 51 and the minute resistor 52 that are suitable for the high temperature superconducting coil 13 of high strength.

[F] Sixth embodiment (FIGS. 6 and 7)
FIG. 6 is an electric circuit diagram showing a high temperature superconducting magnet device to which the superconducting magnet device according to the sixth embodiment is applied. FIG. 7 is an electric circuit diagram showing a modification of the high temperature superconducting magnet device of FIG. In the sixth embodiment, the same parts as those in the first embodiment are designated by the same reference numerals as those in the first embodiment to simplify or omit the description.

  The high temperature superconducting magnet device 65 as the superconducting magnet device of the sixth embodiment is different from that of the first embodiment in that a magnetic field sensor 66 for detecting a magnetic field formed by the high temperature superconducting coil 13 is provided, and as shown in FIG. The resistance value of the variable resistor 67 functioning as the minute resistor 15 is configured to be adjustable based on the detection value of the magnetic field sensor 66 so that the current value of the current flowing from the exciting power supply 16 to the high temperature superconducting coil 13 becomes constant. It is a point. Alternatively, as shown in FIG. 7, the resistance value of the variable resistor 68, which is electrically connected in series to the protection resistor 17 and functions as the protection resistor 17, is set based on the detection value of the magnetic field sensor 66 from the exciting power supply 16 to the high temperature superconducting The current value of the current flowing through the coil 13 may be adjustable so as to be constant.

  The resistance value of each of the variable resistor 67 as the minute resistor 15 or the variable resistor 68 as the protective resistor 17 is adjusted by heating with a heater (not shown) or a heat transfer plate (not shown) by utilizing the temperature dependence of the resistance value, for example. It is implemented by changing the temperature of the variable resistor 67 or 68 by cooling with the refrigerator 18 via the. Further, the minute resistor 15 and the variable resistor 67 as the minute resistor 15 shown in FIGS. 6 and 7 may be thermally connected to the permanent current switch 14 as in the first embodiment.

  With the above configuration, when the minute resistor 15 is thermally connected to the permanent current switch 14, the same effects as the effects (1) and (2) of the first embodiment are achieved. The following effect (10) is achieved.

  (10) Even in a situation where the magnetic field formed by the high-temperature superconducting coil 13 changes due to various factors over a long period of time, the magnetic field sensor 66 detects this magnetic field, and based on this detected value, By adjusting the resistance value of each of the variable resistance 67 or the variable resistance 68 as the protection resistance 17, the current value of the current flowing from the excitation power supply 16 to the superconducting coil 13 can be controlled to be constant. As a result, the magnetic field formed by the high temperature superconducting coil 13 can be stabilized for a long period of time.

  Although some embodiments of the present invention have been described above, 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 forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention, and those replacements and changes can be made. Is included in the scope and gist of the invention, and is also included in the invention described in the claims and its equivalent scope.

10 ... High temperature superconducting magnet device (superconducting magnet device), 13 ... High temperature superconducting coil (superconducting coil), 14 ... Permanent current switch, 15 ... Micro resistor, 16 ... Excitation power supply, 17 ... Protecting resistance, 23 ... Closed loop, 24 ... Temperature rising heater, 27 ... Circuit breaker, 30 ... High temperature superconducting magnet device (superconducting magnet device), 33 ... High temperature superconducting magnet device (superconducting magnet device), 34 ... Permanent current switch, 35 ... High temperature superconducting tape wire (superconducting tape wire) , 36 ... High temperature superconducting pancake coil (superconducting pancake coil), 40 ... High temperature superconducting magnet device (superconducting magnet device), 41 ... Permanent current switch, 42 ... Inner high temperature superconducting tape wire (inner superconducting tape wire), 43 ... Outer side High temperature superconducting tape wire (outer superconducting tape wire), 44 ... Insulating tape, 45 ... High temperature superconducting pancake coil (superconducting tape) Cake coil), 50 ... High temperature superconducting magnet device (superconducting magnet device), 51 ... Permanent current switch, 52 ... Microresistor, 53 ... High temperature superconducting tape wire (superconducting wire), 54 ... Normal conductive metal tape wire (normal conductive metal) Wire material), 55 ... Insulating tape, 56 ... Pancake coil, 57 ... Connection end portion, 58 ... Electrode, 59 ... End portion, 61 ... Protective layer, 65 ... High temperature superconducting magnet device (superconducting magnet device), 66 ... Magnetic field sensor , 67, 68 ... Variable resistance

Claims (8)

A superconducting coil that is composed of a superconducting wire and that forms a magnetic field by supplying an electric current;
An exciting power supply for exciting the superconducting coil by supplying a current to the superconducting coil,
A persistent current switch electrically connected in parallel to the superconducting coil to form a closed loop together with the superconducting coil, and made of a superconducting material,
A minute resistor that is electrically connected in series to the permanent current switch and in parallel to the superconducting coil, respectively, and determines a shunt ratio for shunting the current from the excitation power source to the superconducting coil and the permanent current switch,
A protection resistor that is electrically connected in parallel to the excitation power source and has a resistance value that is set to be larger than that of the minute resistor and smaller than that of the permanent current switch in the normal conduction state and that can consume magnetic energy of the superconducting coil. A superconducting magnet device having:
A superconducting magnet device, wherein the minute resistor is thermally connected to the permanent current switch.   2. The superconducting magnet device according to claim 1, wherein the permanent current switch is configured to be heated to a normal conduction state by being heated by an independently operating temperature raising heater.   The superconductivity according to claim 1 or 2, wherein the permanent current switch is configured as an inductive coil by stacking an even number of pancake coils in which a tape-shaped superconducting wire is wound in a pancake shape. Magnet device.   The permanent current switch is a pancake coil in which two tape-shaped superconducting wires are bundled together with an insulating tape interposed and wound at the same time. Inner ends of the two superconducting wires are connected to each other and outside 3. The superconducting magnet device according to claim 1, wherein the superconducting magnet device is configured as an non-induction coil by forming an end portion of the electrode as an electrode and flowing a current in the opposite direction to the two superconducting wire rods. The permanent current switch and the micro resistor are pancake coils in which a tape-shaped superconducting wire and a tape-shaped normal-conducting metal wire are bundled and wound with an insulating tape interposed, and the superconducting wire is a permanent current switch. As, the normal-conducting metal wire is configured as a minute resistor,
Inner ends of the superconducting wire and the normal-conducting metal wire are connected to each other, one end of the outside serves as an electrode of the permanent current switch, and the other end of the outside serves as an end of the minute resistor. Becomes
The superconducting magnet device according to claim 1 or 2, wherein the permanent current switch is configured as a non-inductive coil by causing currents to flow in opposite directions in the superconducting wire and the normal-conducting metal wire.   The resistance value in the normal conduction state of the permanent current switch is adjusted by changing at least one of the material and the thickness of the protective layer of the superconducting wire, and the resistance value of the minute resistor is the material of the normal conductive metal wire. The superconducting magnet device according to claim 5, wherein the superconducting magnet device is configured to be adjusted by changing at least one of purity and thickness. A superconducting coil that is composed of a superconducting wire and that forms a magnetic field by supplying an electric current;
An exciting power supply for exciting the superconducting coil by supplying a current to the superconducting coil,
A permanent current switch that is electrically connected in parallel to the superconducting coil to form a closed loop together with the superconducting coil, and that is made up of the superconducting wire.
A micro-resistor that is electrically connected in series to the permanent current switch and in parallel to the superconducting coil, respectively, and determines a shunt ratio for shunting the current from the excitation power supply to the superconducting coil and the permanent current switch,
A protective resistor that is electrically connected in parallel to the excitation power source and has a resistance value set to be larger than that of the minute resistor and smaller than that of the permanent current switch in the normal conduction state to consume magnetic energy of the superconducting coil. A superconducting magnet device having:
Equipped with a magnetic field sensor that detects the magnetic field formed by the superconducting coil,
The minute resistor or the protective resistor is configured such that the resistance value can be adjusted based on the detection value of the magnetic field sensor so that the current value of the current flowing from the excitation power supply to the superconducting coil becomes constant. Characteristic superconducting magnet device.   The superconducting coil is a high-temperature superconducting coil made of a high-temperature superconducting wire, and the permanent current switch is made of a high-temperature superconducting material. Superconducting magnet device.

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