JP2011155096A - Superconducting electromagnet device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superconducting electromagnet device having a current limiter, which is composed of a high-temperature conductor and makes a rapid normal conduction transition. <P>SOLUTION: The superconducting electromagnet device includes: a coil which uses a high-temperature superconducting substance having a critical temperature exceeding 18K; a current limiter winding 12 connected to the coil in series; a protective resistance connected to the coil and current limiter winding 12 in parallel; and a permanent current switch which is connected to the coil and current limiter winding 12 in parallel and uses a high-temperature superconductive substance having a critical temperature exceeding 18K. The superconducting electromagnet device has a quench detecting means 8 for detecting a normal conduction state generated by the coil and a magnetic field-increasing means 13 for increasing a magnetic field at the current limiter winding 12, wherein the current limiter winding 12 uses a high-temperature superconducting substance having a critical temperature exceeding 18K, and the magnetic field increasing means 13 increases the magnetic field at the current limiter winding 12 in response to the detection of the normal conduction state generated by the coil, by the quench detecting means 8 to cause the current limiter winding 12 to make a transition from a superconduction state to a normal conduction state. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a superconducting electromagnet apparatus including a high-temperature superconducting coil using a high-temperature superconducting material having a critical temperature exceeding 18K, and more particularly to protection of a high-temperature superconducting coil during a quench.

  The basic circuit of a conventional superconducting electromagnet apparatus is composed of a superconducting coil, an excitation power source that supplies current to the superconducting coil, a permanent current switch that forms a closed circuit for permanent current operation, and a superconducting coil in parallel. It consists of a protective resistor installed. Supplying current from the excitation power supply to the superconducting coil with the permanent current switch open, and then reducing the supply current from the excitation power supply to zero with the permanent current switch closed to make the superconducting coil and permanent current This is a permanent current operation in which the current continues to flow in a closed circuit composed of switches with almost no attenuation. Thereby, the superconducting electromagnet apparatus can hold the magnetic field for a long time (see, for example, Patent Document 1).

  When resistance is generated in a part of the superconducting coil during normal current operation due to normal conduction transition, the stored energy is converted into thermal energy by Joule heat generation, and the coil temperature rises. Due to this temperature rise, the surroundings of a part of the superconducting coil are further transferred from the superconducting state to the normal conducting state, and finally, the normal conducting transition causes a quenching phenomenon that spreads over the entire superconducting coil. Although the superconducting coil can retain a large amount of stored energy, if this stored energy is converted into thermal energy by the quenching phenomenon, the superconducting coil may cause an excessive temperature rise, resulting in performance deterioration or even burning.

  Therefore, in the conventional electromagnet device, the voltage generated at both ends of the superconducting coil due to the resistance generated in the superconducting coil due to the normal conducting transition is applied to the protective resistor, and the current flows through the protective resistor, so that not only the superconducting coil, Even in the protective resistance, the stored energy is consumed by Joule heat generation, and the temperature rise of the superconducting coil is suppressed.

Japanese Patent Laid-Open No. 5-190325 (first term, FIG. 1)

  In the conventional electromagnet device, the time constant of the increase / decrease of the current flowing through the protective resistance due to the normal conductive transition is L1 / (R1 + R2) where L1 is the inductance of the superconducting coil, R1 is the resistance generated in the superconducting coil, and R2 is the protective resistance. It is represented by Thus, the larger the resistance R1 generated in the superconducting coil, the faster the current flowing through the superconducting coil and the protective resistance is attenuated. In addition, as the resistance R1 generated in the superconducting coil increases, the voltage generated in the superconducting coil increases, so the voltage applied to the protective resistance R2 also increases and a large amount of stored energy is consumed.

When the superconducting coil is a high-temperature superconducting coil composed of a high-temperature superconductor having a critical temperature exceeding 18 K, such as magnesium diboride (MgB ₂ ), iron-based superconductor or oxide superconductor, niobium titanium (Nb ₃ Ti) or Compared with a low-temperature superconducting coil composed of a low-temperature superconductor having a critical temperature of 18 K or less, such as niobium tin (Nb ₃ Sn), the critical temperature is in a region having a specific heat of 10 times or more, so the temperature rise is slow. For this reason, expansion of the normal conducting region is delayed, and the high temperature superconducting coil generates heat locally. For this reason, resistance R1 which generate | occur | produces in a high temperature superconducting coil is small compared with a low temperature superconducting coil, a voltage is rapidly applied to protective resistance R2, a current is supplied, and stored energy cannot be consumed.

  Therefore, a current limiting device is installed in series with the high-temperature superconducting coil and in parallel with the protective resistance R2. When the resistance R1 is generated in the high-temperature superconducting coil and a voltage is generated, the current limiter is changed from the superconducting state to the normal conducting state to be in a high resistance state. Since a voltage is generated in the current limiter, this voltage is applied to the protective resistor R2, and a current can flow through the protective resistor R2. By attenuating the current flowing through the high temperature superconducting coil with the current limiter and the protective resistance R2 (current limiting operation) and consuming the stored energy, it is possible to suppress the local temperature rise of the high temperature superconducting coil.

  However, in order to change the current limiter from the superconducting state to the normal conducting state, it is necessary to quickly raise the temperature of the entire current limiting device by heating with a heater or the like, so the specific heat is about 1/1000 of normal temperature. The current limiter was composed of a low-temperature superconductor with a critical temperature in the temperature range. The high-temperature superconducting coil is sufficiently cooled by a refrigerator to maintain the superconducting state. However, the current limiter using the low-temperature superconductor needs to be cooled with a cryogen or the like typified by liquid helium (He). It is thought that it is difficult to sufficiently cool only with the machine.

  If the current limiting device can be composed of a high-temperature superconductor, it is not necessary to cool with a cryogen or the like typified by liquid helium, and it can be sufficiently cooled only with a refrigerator. For this purpose, it is desired that the current limiter can quickly conduct normal conduction throughout the current limiter even if the current limiter is composed of a high-temperature superconductor.

  Accordingly, an object of the present invention is to provide a superconducting electromagnet apparatus including a current limiter that can be formed of a high-temperature superconductor and can be rapidly transferred to normal conduction.

In order to achieve the above object, the features of the present invention are:
A coil using a high-temperature superconducting material having a critical temperature exceeding 18K,
A current limiter winding connected in series with the coil;
A protective resistor connected in parallel with the coil and the current limiter winding;
In a superconducting magnet device comprising a permanent current switch connected in parallel to the coil and the current limiter winding and using a high temperature superconducting material having a critical temperature exceeding 18K,
Quench detecting means for detecting a normal conducting state generated in the coil;
Magnetic field increasing means capable of increasing the magnetic field in the current limiter winding,
The current limiter winding is made of a high temperature superconducting material having a critical temperature exceeding 18K,
The magnetic field increasing means is to increase the magnetic field in the current limiter winding by detecting the normal conducting state of the quench detecting means, and to transfer the current limiter winding from the superconducting state to the normal conducting state. .

  According to the present invention, there is provided a superconducting electromagnet apparatus provided with a current limiter that can be constituted by a high-temperature superconductor and that can rapidly conduct normal conduction.

1 is a circuit diagram of a superconducting electromagnet apparatus according to a first embodiment of the present invention. It is sectional drawing along the central axis of the fault current limiter used for the superconducting electromagnet apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing along the central axis of the fault current limiter used for the superconducting electromagnet apparatus which concerns on the 2nd Embodiment of this invention. It is sectional drawing along the central axis of the fault current limiter used for the superconducting electromagnet apparatus which concerns on the 3rd Embodiment of this invention. It is arrow sectional drawing of the AA direction of FIG. 4A. It is sectional drawing along the central axis of the fault current limiter used for the superconducting electromagnet apparatus which concerns on the 4th Embodiment of this invention. It is arrow sectional drawing of the BB direction of FIG. 5A. It is arrow sectional drawing of the CC direction of FIG. 5A. It is arrow sectional drawing of the DD direction of FIG. 5A. It is arrow sectional drawing of the EE direction of FIG. 5A.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
FIG. 1 shows a circuit diagram of a superconducting electromagnet apparatus 1 according to the first embodiment of the present invention. The superconducting electromagnet apparatus 1 includes a plurality (two in FIG. 1) of high-temperature superconducting coils 3 (3a, 3b: coils) using a high-temperature superconducting material having a critical temperature exceeding 18K, and high-temperature superconducting coils 3 (3a, 3b). ) And a plurality of (two in FIG. 1) current limiters 5 (5a, 5b) and high temperature superconducting coils 3 (3a, 3b) using a high temperature superconducting material having a critical temperature exceeding 18K. And a plurality of (two in FIG. 1) protective resistors 7 (7a, 7b) connected in parallel to the current limiter 5 (5a, 5b), the high-temperature superconducting coil 3 (3a, 3b), and the current limiter 5 (5a, 5b), a permanent current switch 4 using a high temperature superconducting material having a critical temperature exceeding 18K, a high temperature superconducting coil 3 (3a, 3b) and a current limiter 5 (5a, 5b). The excitation power supply 10 connected in series with the power And a circuit breaker 11. A high-temperature superconducting material having a critical temperature exceeding 18K is used for the high-temperature superconducting coil 3 (3a, 3b), the current limiter 5 (5a, 5b), the permanent current switch 4, and the wiring connecting them. Further, the high-temperature superconducting coil 3a, the current limiter 5a, and the protective resistor 7a can be considered to be connected in series to form a closed circuit, and the high-temperature superconducting coil 3b, the current limiting device 5b, and the protective resistor 7b. Can be considered to be connected in series to form a closed circuit.

  The superconducting electromagnet apparatus 1 includes a quench detection means 8 for detecting a normal conduction state generated in the high-temperature superconducting coil 3 (3a, 3b) and a DC power source for supplying a DC current to each of the current limiters 5 (5a, 5b). 6 (6a, 6b). When the quench detection means 8 detects the normal conducting state generated in the high temperature superconducting coil 3 (3a, 3b) as, for example, a change in potential difference between both ends of the high temperature superconducting coil 3 (3a, 3b), the detected high temperature superconducting coil The quench detection signal 9 (9a, 9b) is transmitted to the DC power supply 6 (6a, 6b) on the side corresponding to 3 (3a, 3b). When the DC power supply 6 (6a, 6b) receives the quench detection signal 9 (9a, 9b), it sends a DC current to the current limiter 5 (5a, 5b). When the DC power source 6 (6a, 6b) passes a direct current through the current limiter 5 (5a, 5b), the high temperature superconducting material having a critical temperature exceeding 18K used in the current limiter 5 (5a, 5b) The whole changes from the superconducting state to the normal conducting state, and the current limiter 5 (5a, 5b) generates a high resistance. This generating mechanism will be described in detail later.

  When a part of the high-temperature superconducting coil 3 (3a, 3b) shifts from the superconducting state to the normal conducting state and a resistance (R1) is generated to generate a voltage (potential difference), the quench detection means 8 The normal conducting state generated in the coil 3 (3a, 3b) is detected as a change in potential difference between both ends of the high temperature superconducting coil 3 (3a, 3b). By this detection, the DC power supply 6 (6a, 6b) passes a DC current through the current limiter 5 (5a, 5b). Due to this direct current, the current limiter 5 (5a, 5b) transitions from the superconducting state to the normal conducting state and enters a high resistance state. Since a voltage is generated in the current limiting device 5 (5a, 5b), a voltage corresponding to this voltage is applied to the protective resistor 7 (7a, 7b) (R2), and the protective resistor 7 (7a, 7b) (R2) is applied. Current can flow. The current limiting device 5 (5a, 5b) and the protective resistor 7 (7a, 7b) (R2) attenuate the current flowing through the high-temperature superconducting coil (current-limiting operation) and consume the stored energy, so that the high-temperature superconducting coil 3 ( 3a, 3b) can be prevented from locally raising the temperature.

The high-temperature superconducting coil 3 (3a, 3b) cools and stabilizes the surroundings and gaps of multiple high-temperature superconductors having a critical temperature exceeding 18K, such as magnesium diboride (MgB ₂ ), iron-based superconductors and oxide superconductors. A superconducting wire covered and filled with a chemical is wound around a reel or the like. As the cooling stabilizer, oxygen-free copper (pure copper: Cu) having a low electrical resistivity and high thermal conductivity is used.

  Further, the superconducting electromagnet apparatus 1 has a cryostat 2. The cryostat 2 includes a vacuum vessel 2a for vacuum insulation, a radiation shield 2b that suppresses intrusion of radiant heat, a refrigerator 2c, and a heat transfer means 2d. The radiation shield 2b is contained in the vacuum vessel 2a, and the heat transfer means 2d is contained in the radiation shield 2b. The refrigerator 2c has a first stage that can be cooled below the critical temperature of the high-temperature superconductor, and a second stage that can be cooled to a low temperature, although the temperature is higher than the first stage. The first stage is thermally connected to the heat transfer means 2d, and the heat transfer means 2d is cooled below the critical temperature of the high-temperature superconductor. The second stage is thermally connected to the radiation shield 2b, and the radiation shield 2b is cooled to a low temperature that is higher than the heat transfer means 2d.

  The heat transfer means 2d is thermally connected to the high-temperature superconducting coils 3 (3a, 3b), the permanent current switch 4, and the current limiters 5 (5a, 5b) contained in the radiation shield 2b. It is possible to cool each to below the critical temperature and keep the high temperature superconducting coil 3 (3a, 3b), the permanent current switch 4, and the current limiter 5 (5a, 5b) in a superconducting state. The protective resistor 7 (7a, 7b) may not be thermally connected to the heat transfer means 2d. According to these, the high-temperature superconducting coil 3 (3a, 3b), the permanent current switch 4, and the current limiter 5 (5a, 5b) can be provided without separately preparing a refrigerant container and a refrigerant contained in the radiation shield 2b. The superconducting electromagnet apparatus 1 can be operated while maintaining the superconducting state below the critical temperature.

  Next, the operation of the superconducting electromagnet apparatus 1 will be described. First, the high temperature superconducting coil 3 (3a, 3b), the permanent current switch 4, and the current limiter 5 (5a, 5b) in the cryostat 2 are kept below the critical temperature of the high temperature superconductor used in them, The superconducting state is maintained. First, with the permanent current switch 4 open (off), the current breaker 11 is closed (on), and current is supplied from the exciting power supply 10 to the high-temperature superconducting coil 3 (3a, 3b). Thereafter, the permanent current switch 4 is closed (ON), and further, the current supply from the exciting power supply 10 is stopped, and then the current breaker 11 is opened (OFF). As a result, no current is supplied from the exciting power source 10 to the high temperature superconducting coil 3, but the two high temperature superconducting coils 3 (3a, 3b) and the two current limiters 5 (5a, 5b) are permanently closed (on). The current continues to flow in the closed circuit in which the current switch 4 is connected in series with almost no attenuation in the superconducting state, and the superconducting electromagnet apparatus 1 is in a permanent current operation. In the permanent current operation, the superconducting electromagnet apparatus 1 can form and maintain a magnetic field for a long time without supplying power from the excitation power supply 10.

  Next, a case where a part of one of the two high-temperature superconducting coils 3 (3a, 3b) of the high-temperature superconducting coil 3 (3a, 3b) undergoes a normal-conducting transition from the superconducting state will be described.

  When the normal conduction transition occurs in a part of the high temperature superconducting coil 3a and the potential difference between both ends of the high temperature superconducting coil 3a exceeds a predetermined potential difference, the quench detection means 8 indicates that the predetermined potential difference has been exceeded. It is detected that a normal conducting state has occurred in the coil 3a. The quench detection means 8 transmits a quench detection signal 9a to the DC power supply 6a. When the DC power supply 6a receives the quench detection signal 9a, the DC power supply 6a passes a DC current through the current limiter 5a. When the DC power source 6a passes a DC current through the current limiter 5a, the entire high-temperature superconducting material having a critical temperature exceeding 18K used in the current limiter 5a is changed from the superconducting state to the normal conducting state, The vessel 5a generates a high resistance. Since a voltage is generated in the current limiting device 5a, this voltage is applied to the protective resistor 7a, and a current can flow through the protective resistor 7a. The current flowing through the high temperature superconducting coil is attenuated by the current limiting device 5a and the protective resistor 7a (current limiting operation), and the accumulated energy accumulated in the high temperature superconducting coil 3a and the like is consumed, so that the high temperature superconducting coil 3a is locally heated. The rise can be suppressed.

  FIG. 2 shows a cross-sectional view along the central axis 24 of the current limiter 5 (5a, 5b) used in the superconducting electromagnet apparatus 1 according to the first embodiment of the present invention. The current limiter 5 (5a, 5b) is a cylindrical current limiter casing 21 whose both ends are closed, and a current limiter disposed inside the current limiter casing 21 and wound around the current limiter bobbin 22. Winding 12 is provided. The current limiter winding 12 is connected in series to the high temperature superconducting coil 3 (3a, 3b) and the permanent current switch 4.

  The current limiter winding 12 is non-inductively wound so as not to be magnetically coupled to the high temperature superconducting coil 3 (3a, 3b). As a non-inductive winding method, for example, the current limiting bobbin 22 may be wound so that the number of turns in the rotation direction of the timepiece is equal to the number of turns in the counterclockwise direction of the timepiece. The current limiting coil 12 is made of a high-temperature superconducting material having a critical temperature exceeding 18K.

  Further, the current limiter 5 (5a, 5b) has a magnetic field increasing means 13 capable of increasing the magnetic field in the current limiter winding 12. The magnetic field increasing means 13 includes a moving body 15 having a first permanent magnet 16 and a moving means 14 that moves the moving body 15 and brings the first permanent magnet 16 closer to the current limiter winding 12. The moving means 14 has electromagnets 18a and 18b such as solenoid coils. The electromagnets 18a and 18b are connected to the DC power source 6 (6a and 6b). The electromagnets 18a and 18b are energized by the DC power source 6 (6a and 6b) based on the detection of the normal conduction state generated in the high-temperature superconducting coil 3 (3a and 3b) of the quench detection means 8, and the moving body 15 has. An attractive force or a repulsive force is generated with respect to the first permanent magnet 16. The moving body 15 is moved by this attractive force or repulsive force.

  The moving body 15 is the first permanent magnet 16 itself, and has a cylindrical shape. The inner diameter of the moving body 15 is larger than the outer diameters of the current limiter winding 12 and the current limiter bobbin 22. Further, the direction of the central axis (24) is the same in the current limiter casing 21, the electromagnets 18a and 18b, the moving body 15 (first permanent magnet 16), and the current limiter winding 12. As a result, the movable body 15 moves in the direction of the central axis 24 and can insert the current limiting coil 12 into itself.

  The current limiter winding 12 and the current limiter bobbin 22 are disposed on one of the end faces of the closed end of the cylindrical current limiter casing 21. It should be noted that the end face may be closed as long as the moving body 15 does not jump out of the current limiter 5, and it is not necessary to fully close it, and a hole may be provided in part. The length in the direction of the central axis 24 of the current limiter winding 12 is not more than half of the distance between the end faces of both ends of the current limiter casing 21. The length of the moving body 15 (first permanent magnet 16) in the direction of the central axis 24 is also less than or equal to half of the distance between the end faces of both ends of the current limiter casing 21. Thereby, as shown in FIG. 2, the moving body 15 (first permanent magnet 16) does not insert the current limiter winding 12, and the inner surface of the moving body 15 (first permanent magnet 16) is limited. The current collector winding 12 and the current limiter bobbin 22 can be disposed at positions that do not face the outer surface.

  The electromagnet 18a is disposed in the vicinity of the closed end surface of the current limiter casing 21 on the side where the current limiter winding 12 and the current limiter bobbin 22 are disposed. The electromagnet 18b is disposed in the vicinity of the closed end surface of the current limiter casing 21 on the side opposite to the side where the current limiter winding 12 and the current limiter bobbin 22 are disposed.

  The direction (magnetization direction) from the north pole to the south pole of the first permanent magnet 16 is parallel to the direction of the central axis 24. As shown in FIG. 2, on the electromagnet 18b side of the first permanent magnet 16, an N pole is disposed in the vicinity of the electromagnet 18b. When the electromagnet 18b is energized by the DC power supply 6 (6a, 6b), A current flows in a current direction 19b that generates a repulsive force with respect to the N pole. An S pole is disposed on the electromagnet 18a side away from the electromagnet 18a. When the electromagnet 18a is energized by the DC power supply 6 (6a, 6b), the current direction 19a generates an attractive force for the S pole. Current flows. Due to these repulsive forces and attractive forces, the moving body 15 (first permanent magnet 16) moves in the moving direction 23 and approaches the current limiter winding 12. Then, the magnetic field in the entire current limiter winding 12 increases and reaches the substantially critical magnetic field of the high-temperature superconducting material used in the current limiter winding 12, or the critical temperature and the critical current decrease, and the current limiter The high temperature superconducting material used in the winding 12 transitions from the superconducting state to the normal conducting state throughout the current limiter winding 12.

  When the quenching phenomenon or the like is finished and the superconducting electromagnet apparatus 1 is restarted, the electromagnets 18a and 18b are moved in the direction opposite to the current directions 19a and 19b when the moving body 15 is moved in the moving direction 23. By energizing the current, the moving body 15 is moved in the direction opposite to the moving direction 23 and arranged at a position away from the current limiter winding 12 as shown in FIG.

  In this way, the superconducting electromagnet apparatus 1 quickly moves the moving body 15 (first permanent magnet 16) to the vicinity of the current limiter winding 12 when the normal conducting transition occurs in the high temperature superconducting coil 3. By causing the whole winding 12 to perform normal conduction transition, the current flowing through the high temperature superconducting coil 3 is attenuated (current limiting operation), and it is possible to prevent the high temperature superconducting coil 3 from locally generating heat and degrading performance or burning. In addition, the current limiter 5 can be formed of a high-temperature superconductor, and the cooling structure (cryostat 2) of the superconducting electromagnet apparatus 1 can be simplified.

(Second Embodiment)
FIG. 3 shows a cross-sectional view along the central axis 24 of the current limiting device 5 used in the superconducting electromagnet apparatus according to the second embodiment of the present invention. The superconducting electromagnet apparatus according to the second embodiment is different from the superconducting electromagnet apparatus according to the first embodiment in the current limiter 5, but the other configurations are the same. In the current limiter 5 as well, the second embodiment and the first embodiment are partially different, but the other portions are the same. In the current limiting device 5, the second embodiment is different from the first embodiment in that the moving body 15 (first permanent magnet 16) has a cylindrical shape. Accordingly, the outer diameter of the moving body 15 (first permanent magnet 16) is smaller than the inner diameters of the current limiter winding 12 and the current limiter bobbin 22. In the current limiting operation, the moving body 15 (first permanent magnet 16) moves in the moving direction 23 along the central axis 24 and inserts itself into the current limiter winding 12. During the current limiting operation, the moving body 15 (first permanent magnet 16) is positioned on the inner peripheral side of the current limiter winding 12 and the current limiter bobbin 22. In the first embodiment, the moving body 15 (first permanent magnet 16) is positioned on the outer peripheral side of the current limiter winding 12 and the current limiter bobbin 22 during the current limiting operation. The current limiter bobbin 22 is formed over the entire area between both end faces of the current limiter casing 21. The inner wall of the cylindrical current limiter bobbin 22 serves as a guide for regulating the moving direction of the moving body 15 (first permanent magnet 16).

  According to the second embodiment, not only the same effects as those of the first embodiment can be obtained, but also a gap for moving the moving body 15 needs to be provided on the outer peripheral side of the current limiter winding 12. The outer diameter of the current limiter 5 can be reduced.

(Third embodiment)
FIG. 4A shows a cross-sectional view along the central axis 24 of the current limiting device 5 used in the superconducting electromagnet apparatus according to the third embodiment of the present invention. The superconducting electromagnet apparatus according to the third embodiment is different from the superconducting electromagnet apparatus according to the first embodiment in the current limiting device 5, but the other configurations are the same. In the current limiter 5 as well, the third embodiment and the first embodiment are partially different, but the other portions are the same. In the current limiting device 5, the third embodiment is different from the first embodiment in that the moving body 15 has a plurality of permanent magnets 17 a, 17 b, 161, 164 having different magnetization directions. It is a point. The first permanent magnet 16 of the first embodiment has a first function for increasing the magnetic field strength in the current limiter winding 12 after moving to the vicinity of the current limiter winding 12, and in the vicinity of the current limiter winding 12. In order to move, the electromagnets 18a and 18b had a second function of generating an attractive force and a repulsive force. In the third embodiment, the moving body 15 is provided with a permanent magnet specialized for each function. First permanent magnets 161 and 164 are provided to increase the magnetic field strength in the current limiter winding 12 after moving to the vicinity of the current limiting current limiter winding 12. Second permanent magnets 17a and 17b are provided to move to the vicinity of the current-limiting current limiter winding 12 and generate attractive and repulsive forces on the electromagnets 18a and 18b. Therefore, in the first embodiment, it can be considered that the first permanent magnet 16 also serves as the second permanent magnet. In the third embodiment, the first permanent magnets 161 and 164 and the second permanent magnets 17 a and 17 b are embedded in the nonmagnetic member 25 and integrated to form the moving body 15. The moving body 15 is a so-called combination magnet.

The first permanent magnets 161 and 164 are arranged such that the magnetization direction is substantially perpendicular to the direction in which the moving body 15 moves (the direction of the central axis 24). The second permanent magnets 17a and 17b are arranged such that the magnetization direction is substantially parallel to the direction in which the moving body 15 moves (the direction of the central axis 24). The direction (magnetization direction) from the north pole to the south pole of the second permanent magnet 17a coincides with the direction (magnetization direction) from the north pole to the south pole of the second permanent magnet 17b.
The first permanent magnets 161 and 164 are arranged at the center in the direction of the central axis 24 of the moving body 15. The second permanent magnets 17 a and 17 b are disposed at both ends in the direction of the central axis 24 of the moving body 15. The second permanent magnets 17 a and 17 b are arranged so as to sandwich the first permanent magnets 161 and 164 with respect to the direction of the central axis 24.

  FIG. 4B shows a cross-sectional view taken along the line AA in FIG. 4A. The first permanent magnet is not limited to the first permanent magnets 161 and 164 shown in FIG. 4A. The moving body 15 has six first permanent magnets 161 to 166 embedded in the nonmagnetic member 25. The 1st permanent magnets 161-166 are arrange | positioned at equal intervals in the circumferential direction of the mobile body 15, and the magnetization direction is the opposite direction in radial direction among adjacent 1st permanent magnets 161-166. For this reason, it is preferable that the first permanent magnets 161 to 166 are an even number.

  According to the third embodiment, the second permanent magnets 17a and 17b not only provide the effect of the second function similar to that of the first embodiment, but also the moving body 15 by the first permanent magnets 161 to 166. A multipolar magnetic field in which the magnetic lines of force 26 are concentrated on the inner peripheral side of the current can be generated, and the magnetic flux density (magnetic field) applied to the current limiter winding 12 during the current limiting operation is increased. In comparison, the first function is enhanced, and the current limiting operation can be performed quickly.

(Fourth embodiment)
FIG. 5A shows a cross-sectional view along the central axis 24 of the current limiter 5 used in the superconducting electromagnet apparatus according to the fourth embodiment of the present invention. The superconducting electromagnet apparatus according to the fourth embodiment is different from the superconducting electromagnet apparatus according to the second embodiment in the current limiter 5, but the other configurations are the same. Also in the current limiter 5, the fourth embodiment and the second embodiment are partially different, but the other portions are the same. In the current limiting device 5, the fourth embodiment is different from the second embodiment in that the moving body 15 includes a plurality of permanent magnets 16 a to 16 d, 17 a, and 17 b having different magnetization directions. It is a point. The first permanent magnet 16 of the second embodiment includes a first function for increasing the magnetic field strength in the current limiter winding 12 after moving to the vicinity of the current limiter winding 12 and the vicinity of the current limiter winding 12. In order to move, the electromagnets 18a and 18b had a second function of generating an attractive force and a repulsive force. In the fourth embodiment, the movable body 15 is provided with a permanent magnet specialized for each function. First permanent magnets 16a to 16d are provided to increase the magnetic field strength in the current limiter winding 12 after moving to the vicinity of the current limiting current limiter winding 12. Second permanent magnets 17a and 17b are provided to generate attractive and repulsive forces on the electromagnets 18a and 18b in order to move to the vicinity of the current-limiting current limiter winding 12. Therefore, in the second embodiment, it can be considered that the first permanent magnet 16 also serves as the second permanent magnet. In the fourth embodiment, the first permanent magnets 16 a to 16 d and the second permanent magnets 17 a and 17 b are embedded in the nonmagnetic member 25 and integrated to constitute the moving body 15. The moving body 15 is a so-called combination magnet.

The first permanent magnets 16a to 16d are arranged so that the magnetization direction is substantially perpendicular to the direction in which the moving body 15 moves (the direction of the central axis 24). The second permanent magnets 17a and 17b are arranged such that the magnetization direction is substantially parallel to the direction in which the moving body 15 moves (the direction of the central axis 24). The direction (magnetization direction) from the north pole to the south pole of the second permanent magnet 17a coincides with the direction (magnetization direction) from the north pole to the south pole of the second permanent magnet 17b.
The first permanent magnets 16 a to 16 d are arranged at equal intervals in the center in the direction of the central axis 24 of the moving body 15. The second permanent magnets 17 a and 17 b are disposed at both ends in the direction of the central axis 24 of the moving body 15. The second permanent magnets 17 a and 17 b are arranged so as to sandwich the first permanent magnets 16 a to 16 d with respect to the direction of the central axis 24.

  FIG. 5B shows a cross-sectional view in the direction of arrow BB in FIG. 5A. The first permanent magnet 16a is arranged so that the direction from the N pole to the S pole (magnetization direction) is substantially perpendicular to the direction in which the moving body 15 moves (the direction of the central axis 24). Thereby, the magnetic force line 26 reaches the current limiter winding 12 and further penetrates, so that the magnetic flux density (magnetic field) applied to the current limiter winding 12 during the current limiting operation can be increased. The magnetization direction of the first permanent magnet 16a is set to the direction from the bottom to the top of the page.

  FIG. 5C shows a cross-sectional view taken along the line CC in FIG. 5A. The first permanent magnet 16b is arranged so that the direction from the N pole to the S pole (magnetization direction) is substantially perpendicular to the direction in which the moving body 15 moves (the direction of the central axis 24). Thereby, the magnetic force line 26 reaches the current limiter winding 12 and further penetrates, so that the magnetic flux density (magnetic field) applied to the current limiter winding 12 during the current limiting operation can be increased. The magnetization direction of the first permanent magnet 16b is set to a direction rotated 45 degrees clockwise from the magnetization direction of the first permanent magnet 16a (the direction from the bottom to the top of the page).

  FIG. 5D shows an arrow cross-sectional view in the DD direction of FIG. 5A. The first permanent magnet 16c is arranged so that the direction from the N pole to the S pole (magnetization direction) is substantially perpendicular to the direction in which the moving body 15 moves (the direction of the central axis 24). Thereby, the magnetic force line 26 reaches the current limiter winding 12 and further penetrates, so that the magnetic flux density (magnetic field) applied to the current limiter winding 12 during the current limiting operation can be increased. The magnetization direction of the first permanent magnet 16c is set to a direction rotated 90 degrees clockwise from the magnetization direction of the first permanent magnet 16a (the direction from the bottom to the top of the page).

  FIG. 5E shows an arrow cross-sectional view in the EE direction of FIG. 5A. 16 d of 1st permanent magnets are arrange | positioned so that the direction (magnetization direction) which goes to a south pole from a north pole with respect to the direction (direction of the central axis 24) to which the mobile body 15 moves may be substantially perpendicular | vertical. Thereby, the magnetic force line 26 reaches the current limiter winding 12 and further penetrates, so that the magnetic flux density (magnetic field) applied to the current limiter winding 12 during the current limiting operation can be increased. The magnetizing direction of the first permanent magnet 16d is set to a direction rotated 135 degrees clockwise from the magnetizing direction of the first permanent magnet 16a (the direction from the bottom to the top of the page). That is, the magnetization directions of the first permanent magnets 16a to 16b are different from each other and are evenly shifted by 45 degrees.

  According to the fourth embodiment, the second permanent magnets 17a and 17b not only provide the effect of the second function similar to that of the first embodiment, but also the magnetic lines of force 26 are generated by the first permanent magnets 16a to 16b. Utilizing the concentration of the first permanent magnets 16a to 16b in the vicinity of the N pole and the S pole, the magnetic flux density (magnetic field) applied to the current limiter winding 12 during the current limiting operation is increased, so that the second Compared with the embodiment, the first function is enhanced, and the current limiting operation can be performed promptly. In addition, since the magnetization directions of the first permanent magnets 16a to 16b are uniformly shifted and different, the circumferential magnetic flux density distribution (magnetic field strength) is not only increased, but also becomes uniform, and the current limiter The winding 12 can be transferred to the normal conducting state as a whole.

DESCRIPTION OF SYMBOLS 1 Superconducting electromagnet apparatus 2 Cryostat 2a Vacuum vessel 2b Radiation shield 2c Refrigerator 2d Heat transfer means 3, 3a, 3b High temperature superconducting coil 4 Permanent current switch 5, 5a, 5b Current limiter 6, 6a, 6b DC power supply 7, 7a, 7b Protection resistance 8 Quench detection means 9, 9a, 9b Quench detection signal 10 Excitation power source 11 Current breaker 12 Current limiter winding 13 Magnetic field increasing means 14 Moving means 15 Moving body (combined magnet)
16, 161, 162, 163, 164, 165, 166, 16a, 16b, 16c, 16d First permanent magnet (16), 17a, 17b Second permanent magnet 18a, 18b Electromagnet (solenoid coil)
19a, 19b Current direction 21 Current limiter casing 22 Current limiter bobbin 23 Movement direction 24 Central axis 25 Nonmagnetic member 26 Magnetic field line

Claims (9)

A coil using a high-temperature superconducting material having a critical temperature exceeding 18K,
A current limiter winding connected in series with the coil;
A protective resistor connected in parallel with the coil and the current limiter winding;
In a superconducting magnet device comprising a permanent current switch connected in parallel to the coil and the current limiter winding and using a high temperature superconducting material having a critical temperature exceeding 18K,
Quench detecting means for detecting a normal conducting state generated in the coil;
Magnetic field increasing means capable of increasing the magnetic field in the current limiter winding,
The current limiter winding is made of a high temperature superconducting material having a critical temperature exceeding 18K,
The magnetic field increasing means increases the magnetic field in the current limiter winding by detecting the normal conducting state of the quench detecting means, and shifts the current limiter winding from the superconducting state to the normal conducting state. Superconducting electromagnet device. The current limiter winding is wound inductively,
The magnetic field increasing means includes
A moving body having a first permanent magnet;
Moving means for moving the moving body to bring the first permanent magnet closer to the current limiter winding;
The superconducting electromagnet apparatus according to claim 1, wherein the magnetic field in the current limiter winding is increased by bringing the first permanent magnet closer to the current limiter winding. The moving body has a second permanent magnet,
The moving means includes an electromagnet that is energized by detecting a normal conducting state generated in the coil of the quench detecting means and generates an attractive force or a repulsive force with respect to the second permanent magnet, and the electromagnet generates the electromagnet. The superconducting electromagnet apparatus according to claim 2, wherein the moving body is moved by attractive force or repulsive force. The moving body has a cylindrical shape,
The inner diameter of the moving body is larger than the outer diameter of the current limiter winding,
The superconducting magnet device according to claim 3, wherein the movable body moves in a direction of a central axis of the cylindrical shape to insert the current limiting coil. The moving body has a cylindrical shape,
The outer diameter of the moving body is smaller than the inner diameter of the current limiter winding,
The superconducting magnet device according to claim 3, wherein the movable body moves in the direction of the central axis of the columnar shape and is inserted into the current limiter winding.   The first permanent magnet also serves as the second permanent magnet, and is arranged so that a magnetization direction is substantially parallel to a direction in which the moving body moves. The superconducting magnet device according to any one of 5. The moving body includes the first permanent magnet and the second permanent magnet,
The first permanent magnet is arranged so that the magnetization direction is substantially perpendicular to the direction in which the moving body moves. The second permanent magnet has a magnetization direction in the direction in which the moving body moves. The superconducting magnet device according to any one of claims 3 to 5, wherein the superconducting magnet device is disposed so as to be substantially parallel to each other.   The said 1st permanent magnet is arrange | positioned at equal intervals in the circumferential direction of the said mobile body, The magnetizing direction is the opposite direction between said adjacent 1st permanent magnets, The Claims 3 thru | or 3 characterized by the above-mentioned. 8. The superconducting electromagnet device according to any one of 7 above.   The superconductivity according to any one of claims 3 to 7, wherein the first permanent magnets are arranged at equal intervals in a direction in which the moving body moves, and the magnetization directions thereof are different from each other. Electromagnet device.

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