DC magnetic field superconducting coil power supply unit

Abstract

A DC magnetic field superconducting coil power supply device for use in a DC magnetic field generator using a superconducting coil that can handle large capacity output currents is realized at low cost. [Solution] A superconducting coil power supply device for a DC magnetic field comprises a superconducting coil, a power supply device capable of supplying DC voltage, and a plurality of basic circuit units, each of which comprises a plurality of chopper circuits connected in parallel between one end of the power supply device and one end of the superconducting coil, and a control unit that controls the plurality of chopper circuits, and the control unit operates the plurality of chopper circuits in a time-division manner when the superconducting coil is being charged.

Description

[Technical Field]

[0001] The present disclosure relates to a DC magnetic field superconducting coil power supply device. [Background technology]

[0002] 2. Description of the Related Art DC magnetic field generators using superconducting coils have been known in the past. In order to generate a high magnetic field using a DC magnetic field generator using a superconducting coil, it is necessary to pass a large current through the superconducting coil.

[0003] As a technique for passing a large current through a superconducting coil, a technique is known in which the current passing through the superconducting coil is gradually increased to charge the superconducting coil, thereby passing a large current through the superconducting coil.

[0004] For example, Patent Document 1 discloses a technique for gradually increasing the current flowing through a superconducting magnet by repeatedly turning on and off a switch installed between an exciting transformer capable of supplying current and the superconducting magnet. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2011 / 074092 Summary of the Invention [Problem to be solved by the invention]

[0006] When charging a superconducting coil, a current is usually supplied to the superconducting coil from a power supply via a lead. Because a large current needs to be supplied, the power supply and the lead must be able to handle the large current, but power supplies and leads that can handle large currents are expensive.

[0007] An object of the present disclosure is to realize, at low cost, a DC magnetic field superconducting coil power supply device used in a DC magnetic field generator using a superconducting coil that can handle large capacity output currents. [Means for solving the problem]

[0008] The DC magnetic field superconducting coil power supply device according to the present disclosure comprises: a superconducting coil; a power supply device capable of supplying DC voltage; a plurality of basic circuit units; The basic circuit unit comprises: a plurality of chopper circuits connected in parallel between one end of the power supply device and one end of the superconducting coil; a control unit that controls the plurality of chopper circuits, The control unit operates the plurality of chopper circuits in a time-division manner when the superconducting coil is being charged.

[0009] In the DC magnetic field superconducting coil power supply device according to the present disclosure, The control unit operates each chopper circuit of each basic circuit unit once during one cycle.

[0010] In the DC magnetic field superconducting coil power supply device according to the present disclosure, The superconducting coil further includes a low resistance switch capable of short-circuiting both ends of the superconducting coil.

[0011] In the DC magnetic field superconducting coil power supply device according to the present disclosure, a first master control unit that controls the control unit; The first master control unit operates the plurality of basic circuit units without phase control.

[0012] In the DC magnetic field superconducting coil power supply device according to the present disclosure, a first master control unit that controls the control unit; The first master control unit operates the plurality of basic circuit units in the same phase.

[0013] In the DC magnetic field superconducting coil power supply device according to the present disclosure, a first master control unit that controls the control unit; When the number of the plurality of basic circuit units is M, the first master control unit operates the plurality of basic circuit units with a phase shift of 2π / M.

[0014] In the DC magnetic field superconducting coil power supply device according to the present disclosure, One of the control units is a second master control unit that controls the other control units, The second master control unit operates the plurality of basic circuit units without phase control.

[0015] In the DC magnetic field superconducting coil power supply device according to the present disclosure, One of the control units is a second master control unit that controls the other control units, The second master control unit operates the plurality of basic circuit units in the same phase.

[0016] In the DC magnetic field superconducting coil power supply device according to the present disclosure, One of the control units is a second master control unit that controls the other control units, When the number of the basic circuit units is M, the second master control unit operates the basic circuit units with a phase shift of 2π / M.

[0017] In the DC magnetic field superconducting coil power supply device according to the present disclosure, The chopper circuit is a first switch and an inductor that connect one end of the power supply device and one end of the superconducting coil in series; The inverter further comprises a second switch connecting a node between the first switch and the inductor to ground.

[0018] In the DC magnetic field superconducting coil power supply device according to the present disclosure, The basic circuit unit further includes a suppression reactor connected between the ground and the other end of the superconducting coil.

[0019] In the DC magnetic field superconducting coil power supply device according to the present disclosure, The basic circuit unit further includes a suppression reactor connected between the plurality of chopper circuits and one end of the superconducting coil.

[0020] In the DC magnetic field superconducting coil power supply device according to the present disclosure, A plurality of the power supply devices are provided, The basic circuit unit comprises: The power supply further comprises one of the plurality of power supply devices.

[0021] In the DC magnetic field superconducting coil power supply device according to the present disclosure, a plurality of low-resistance switches capable of short-circuiting both ends of the superconducting coil; The basic circuit unit comprises: The switch further comprises one of the plurality of low resistance switches.

[0022] In the DC magnetic field superconducting coil power supply device according to the present disclosure, The chopper circuit is a first switch and an inductor that connect one end of the power supply device and one end of the superconducting coil in series; The inverter further comprises a second switch connecting a node between the first switch and the inductor to ground.

[0023] In the DC magnetic field superconducting coil power supply device according to the present disclosure, The basic circuit unit further includes a suppression reactor connected between the ground and the other end of the superconducting coil.

[0024] In the DC magnetic field superconducting coil power supply device according to the present disclosure, The basic circuit unit further includes a suppression reactor connected between the plurality of chopper circuits and one end of the superconducting coil. [Effects of the Invention]

[0025] According to the present disclosure, it is possible to realize at low cost a superconducting coil power supply device for a DC magnetic field used in a DC magnetic field generator using a superconducting coil that can handle large capacity output currents. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a diagram illustrating an example of the configuration of a DC magnetic field superconducting coil power supply device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a basic circuit unit. [Figure 3] FIG. 2 is a diagram illustrating an example of the configuration of a chopper circuit. [Figure 4] FIG. 1 is a diagram illustrating an example of the configuration of a low-resistance switch. [Figure 5] 10 is a timing chart showing an example of the on / off timing of a switch of a chopper circuit. [Figure 6] FIG. 1 is a diagram showing the configuration of a DC magnetic field superconducting coil power supply device according to the prior art. [Figure 7] FIG. 10 is a diagram showing the configuration of a DC magnetic field superconducting coil power supply device according to a first modified example of the present disclosure. [Figure 8] FIG. 10 is a diagram showing the configuration of a DC magnetic field superconducting coil power supply device according to a second modified example of the present disclosure. [Figure 9] FIG. 10 is a diagram showing the configuration of a DC magnetic field superconducting coil power supply device according to a third modified example of the present disclosure. [Figure 10] FIG. 10 is a diagram showing the configuration of a DC magnetic field superconducting coil power supply device according to a fourth modified example of the present disclosure. [Figure 11] FIG. 10 is a diagram showing the configuration of a DC magnetic field superconducting coil power supply device according to a fifth modified example of the present disclosure. [Figure 12] FIG. 10 is a diagram showing the configuration of a DC magnetic field superconducting coil power supply device according to a sixth modified example of the present disclosure. [Figure 13] FIG. 13 is a diagram showing the configuration of a DC magnetic field superconducting coil power supply device according to a seventh modified example of the present disclosure. [Figure 14]10 is a flowchart illustrating an example of the operation of a DC magnetic field superconducting coil power supply device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0028] FIG. 1 is a diagram showing an example of the configuration of a DC magnetic field superconducting coil power supply device 1 according to an embodiment of the present disclosure.

[0029] The DC magnetic field superconducting coil power supply device 1 includes a power supply device 11, first leads 12-1 to 12-2, basic circuit units 13-1 to 13-3, a low resistance switch 14, a current sensor 15, second leads 16-1 to 16-2, a superconducting coil 17, and a first master control unit 18.

[0030] Hereinafter, the first leads 12-1 and 12-2 may be simply referred to as "first leads 12" when there is no particular need to distinguish between them.

[0031] Hereinafter, when there is no particular need to distinguish between the basic circuit units 13-1 to 13-3, they may be simply referred to as "basic circuit units 13."

[0032] Hereinafter, the second leads 16-1 to 16-2 may be simply referred to as "second leads 16" when there is no particular need to distinguish between them.

[0033] The first lead 12 , the basic circuit unit 13 , the low resistance switch 14 , the current sensor 15 , the second lead 16 , the superconducting coil 17 and the first master control unit 18 are installed inside the cooling vessel 5 .

[0034] The cooling vessel 5 is a device capable of cooling the inside to a low temperature. For example, the cooling vessel 5 is capable of cooling the inside to about 20K.

[0035] The power supply device 11 is a device capable of supplying DC voltage. The power supply device 11 may include, for example, an AC / DC converter that converts AC voltage supplied from a commercial power source or the like into DC voltage. The DC voltage supplied by the power supply device 11 may be, for example, about 6 V.

[0036] A first lead 12-1 and a first lead 12-2 are connected to two output terminals of the power supply device 11. One output terminal of the power supply device 11 is connected to a plurality of basic circuit units 13-1 to 13-3 via the first lead 12-1. The other output terminal of the power supply device 11 is connected to a low-resistance switch 14 and a second lead 16-2 via the first lead 12-2. In addition, the first lead 12-2, the second lead 16-2, and the low-resistance switch 14 are connected to the ground of each chopper circuit 131 described later.

[0037] The first lead 12 is a conductor capable of passing an electric current.

[0038] The plurality of basic circuit units 13-1 to 13-3 are connected in parallel between one end of the power supply device 11 and one end of the superconducting coil 17. In this embodiment, the term "connected" means not only direct connection but also indirect connection.

[0039] Since the basic circuit units 13-1 to 13-3 have the same configuration, the basic circuit unit 13-1 will be taken as an example for explanation.

[0040] 2 shows an example of the configuration of the basic circuit unit 13-1. The basic circuit unit 13-1 includes a plurality of chopper circuits 131-1 to 131-8 and a control unit 19. Hereinafter, when there is no particular need to distinguish between the chopper circuits 131-1 to 131-8, they may be simply referred to as "chopper circuits 131."

[0041] One of the plurality of chopper circuits 131-1 to 131-8 connected in parallel is connected to one end of power supply device 11 via first lead 12-1. The other of the plurality of chopper circuits 131-1 to 131-8 connected in parallel is connected to one end of superconducting coil 17 via current sensor 15 and second lead 16-1. The ground of each chopper circuit 131 is connected to low resistance switch 14, and is connected to the other end of power supply device 11 via first lead 12-2 and the other end of superconducting coil 17 via second lead 16-2.

[0042] In this embodiment, a configuration in which three basic circuit units 13-1 to 13-3 are connected in parallel will be described as an example, but the number of basic circuit units 13 connected in parallel is not limited to 3. The number of basic circuit units 13 connected in parallel may be any number equal to or greater than two.

[0043] Similarly, in this embodiment, a configuration in which eight chopper circuits 131-1 to 131-8 are connected in parallel will be described as an example, but the number of chopper circuits 131 connected in parallel is not limited to 8. The number of chopper circuits 131 connected in parallel may be any number equal to or greater than two.

[0044] The chopper circuit 131-1 includes a first switch SA1, a second switch SB1, and an inductor L1. Similarly, the chopper circuit 131-2 includes a first switch SA2, a second switch SB2, and an inductor L2. Similarly, the chopper circuit 131-8 includes a first switch SA8, a second switch SB8, and an inductor L8. The chopper circuits 131-3 to 131-7 are not shown in FIG.

[0045] Since the chopper circuits 131-1 to 131-8 have the same configuration, the chopper circuit 131-1 will be taken as an example for explanation.

[0046] The first switch SA1 and inductor L1 of the chopper circuit 131-1 connect in series one end of the power supply device 11 and one end of the superconducting coil 17. The second switch SB1 connects a node between the first switch SA1 and the inductor L1 to the ground.

[0047] The chopper circuit 131-1 charges the superconducting coil 17 and the inductor L1 with a current supplied from the power supply device 11 when the first switch SA1 is on and the second switch SB1 is off.

[0048] The first switch SA1 and the second switch SB1 of the chopper circuit 131-1 are controlled by the control unit 19.

[0049] 3 shows an example of the circuit configuration of the chopper circuit 131-1. As shown in FIG. 3, the first switch SA1 and the second switch SB1 may be MOSFETs. The first switch SA1 may be a P-channel MOSFET. The second switch SB1 may be an N-channel MOSFET.

[0050] When the first switch SA1 and the second switch SB1 are MOSFETs, the gates of the MOSFETs are controlled by the control unit 19.

[0051] By using MOSFETs as the first switch SA1 and the second switch SB1, the operation speed of the first switch SA1 and the second switch SB1 can be increased. Furthermore, by using MOSFETs as the first switch SA1 and the second switch SB1, the on-resistance of the MOSFETs is small, so that the conduction loss of the first switch SA1 and the second switch SB1 can be reduced.

[0052] Since the chopper circuit 131-1 is installed inside the cooling container 5, the on-resistance of the first switch SA1 and the second switch SB1 is smaller than when they are installed at room temperature. Also, since the chopper circuit 131-1 is installed inside the cooling container 5, the series resistance value of the inductor L1 is smaller than when they are installed at room temperature.

[0053] Low-resistance switch 14 is a switch that can short-circuit both ends of superconducting coil 17. One end of low-resistance switch 14 is connected to one end of superconducting coil 17 via current sensor 15 and second lead 16-1. The other end of low-resistance switch 14 is connected to the other end of superconducting coil 17 via second lead 16-2.

[0054] It should be noted that low resistance switch 14 short-circuiting both ends of superconducting coil 17 does not mean a complete short circuit, but means that low resistance switch 14 connects both ends of superconducting coil 17 with a resistance value equal to or less than a predetermined resistance value. The predetermined resistance value may be, for example, about 0.01 to 0.1 mΩ.

[0055] The on / off of low-resistance switch 14 is controlled by first master control unit 18. While superconducting coil 17 is being charged, low-resistance switch 14 is off. That is, while superconducting coil 17 is being charged, low-resistance switch 14 does not short-circuit both ends of superconducting coil 17. When charging of superconducting coil 17 is completed, low-resistance switch 14 is turned on. That is, when charging of superconducting coil 17 is completed, low-resistance switch 14 short-circuits both ends of superconducting coil 17.

[0056] When charging of the superconducting coil 17 is completed and the low resistance switch 14 is turned on, a current flows through the closed loop connecting the low resistance switch 14, the current sensor 15, the second lead 16-1, the superconducting coil 17 and the second lead 16-2.

[0057] 4 shows an example of the circuit configuration of the low-resistance switch 14. The low-resistance switch 14 may have a configuration in which a plurality of parallel circuits, each of which is made up of a MOSFET 141 and a diode 142, are connected in parallel. The low-resistance switch 14 may also have a configuration including a MOSFET 141 having a plurality of parasitic diodes connected in parallel. The low-resistance switch 14 may have a configuration in which, for example, ten parallel circuits, each of which is made up of a MOSFET 141 and a diode 142, are connected in parallel. Note that the MOSFET 141 may be a type of circuit element other than a MOSFET, as long as it can function as a switch.

[0058] Since the low resistance switch 14 is installed inside the cooling vessel 5, the on-resistance of the MOSFET 141 is smaller than when it is installed at room temperature.

[0059] In this way, by configuring low resistance switch 14 to include low loss MOSFET 141, it is possible to reduce loss when current is passed through superconducting coil 17 in a closed loop.

[0060] The current sensor 15 detects the current flowing through the superconducting coil 17. The current sensor 15 may be, for example, a CT (Current Transformer).

[0061] The second lead 16 is a conductor capable of passing a current. The second lead 16 may be, for example, a superconducting current lead. Since the resistance value of a superconducting current lead is approximately zero, the cross-sectional area of ​​the lead can be reduced. Therefore, the superconducting current lead has high thermal insulation properties, and can suppress the transfer of heat to the superconducting coil 17.

[0062] The superconducting coil 17 may include a coil formed from high-temperature superconducting wire. The superconducting coil 17 may be, for example, an uninsulated coil in which a metal tape of a relatively high-resistance normal-conducting material is sandwiched between coil-shaped high-temperature superconducting wire. If the superconducting coil 17 is an uninsulated coil, deterioration of the mechanical properties of the superconducting coil 17 can be prevented. Furthermore, if the superconducting coil 17 is an uninsulated coil, thermal runaway of the superconducting coil 17 can be suppressed, improving stability.

[0063] First master control unit 18 controls control unit 19 included in basic circuit unit 13. First master control unit 18 also controls the entire DC magnetic field superconducting coil power supply device 1. Details of the operation of first master control unit 18 will be described later.

[0064] First master control unit 18 may have a configuration including a logic IC without including a processor such as a CPU (Central Processing Unit), or may have a configuration including a processor such as a CPU.

[0065] If first master control unit 18 is configured not to include a processor such as a CPU, it is possible to improve the reliability of first master control unit 18. Alternatively, if first master control unit 18 is configured to include a processor such as a CPU, first master control unit 18 will be able to perform advanced processing.

[0066] The control unit 19 included in the basic circuit unit 13 controls the operation of the chopper circuit 131. The control unit 19 controls the operations of the chopper circuits 131-1 to 131-8 by controlling the first switches SA1 to SA8 and the second switches SB1 to SB8.

[0067] Control unit 19 operates a plurality of chopper circuits 131-1 to 131-8 in a time-division manner when charging superconducting coil 17. Details of the control of a plurality of chopper circuits 131-1 to 131-8 by control unit 19 will be described later.

[0068] The control unit 19 may have a configuration including a logic IC without including a processor such as a CPU (Central Processing Unit), or may have a configuration including a processor such as a CPU.

[0069] If the control unit 19 is configured not to include a processor such as a CPU, it is possible to improve the reliability of the control unit 19. Alternatively, if the control unit 19 is configured to include a processor such as a CPU, the control unit 19 can perform advanced processing.

[0070] Next, the operation of the DC magnetic field superconducting coil power supply device 1 to charge the superconducting coil 17 will be described in detail.

[0071] When charging of superconducting coil 17 starts, first master control unit 18 controls low resistance switch 14 to be turned off.

[0072] Subsequently, the control unit 19 operates the plurality of chopper circuits 131 in a time-division manner to charge the superconducting coil 17 .

[0073] Operating the multiple chopper circuits 131 in a time-division manner means dividing the time of one cycle by the number of chopper circuits 131 and operating one chopper circuit 131 in each divided time. In other words, the control unit 19 operates each chopper circuit 131 once during one cycle.

[0074] 2, the number of chopper circuits 131 is eight. Control of chopper circuits 131-1 to 131-8 by control unit 19 when the number of chopper circuits 131 is eight will be described with reference to the timing chart shown in FIG.

[0075] The control unit 19 divides one cycle into eight parts, and in the example shown in Fig. 5, operates each chopper circuit 131 in turn for each 1 / 8 cycle. One cycle is the time from t1 to t17. The control unit 19 operates chopper circuit 131-1 from t1 to t3. The control unit 19 operates chopper circuit 131-2 from t3 to t5. The control unit 19 operates chopper circuit 131-8 from t15 to t17. Note that in the timing chart shown in Fig. 5, control of chopper circuits 131-3 to 131-7 is omitted.

[0076] Between t1 and t2, the control unit 19 controls the first switch SA1 of the chopper circuit 131-1 to be on and the second switch SB1 to be off. At this time, the control unit 19 controls the first switches SA2 to SA8 of the other chopper circuits 131-2 to 131-8 to be off and the second switches SB2 to SB8 to be on.

[0077] By this control, the inductor L1 and the superconducting coil 17 of the chopper circuit 131-1 are charged by the current supplied from the power supply device 11 between t1 and t2.

[0078] Subsequently, from t2 to t3, the control unit 19 controls the first switch SA1 of the chopper circuit 131-1 to be off and the second switch SB1 to be on. At this time, the control unit 18 controls the first switches SA2 to SA8 of the other chopper circuits 131-2 to 131-8 to be off and the second switches SB2 to SB8 to be on.

[0079] Subsequently, from t3 to t4, the control unit 19 controls the first switch SA2 of the chopper circuit 131-2 to be on and the second switch SB2 to be off. At this time, the control unit 19 controls the first switches SA1 and SA3 to SA8 of the other chopper circuits 131-1 and 131-3 to 131-8 to be off and the second switches SB1 and SB3 to SB8 to be on.

[0080] By this control, the inductor L2 and the superconducting coil 17 of the chopper circuit 131-2 are charged by the current supplied from the power supply device 11 from t3 to t4.

[0081] Subsequently, from t4 to t5, the control unit 19 controls the first switch SA2 of the chopper circuit 131-2 to be off and the second switch SB2 to be on. At this time, the control unit 19 controls the first switches SA1 and SA3 to SA8 of the other chopper circuits 131-1 and 131-3 to 131-8 to be off and the second switches SB1 and SB3 to SB8 to be on.

[0082] The control unit 19 repeats this process sequentially for the chopper circuits 131-3 to 131-8. When the operation of the chopper circuit 131-8 ends, that is, when t17 shown in Fig. 5 is reached, the control unit 19 returns to the process of operating the chopper circuit 131-1, and repeats the same process.

[0083] In this manner, control unit 19 repeats the processing shown in t1 to t17 of FIG.

[0084] The first master control unit 18 controls the control unit 19 provided in the basic circuit unit 13, and controls the phase in which the multiple basic circuit units 13 operate. The first master control unit 18, for example, operates the multiple basic circuit units 13 in the same phase. In this case, the commands sent from the first master control unit 18 to the control unit 19 of each basic circuit unit 13 are the same, so that the operation of each basic circuit unit 13 can be easily controlled.

[0085] The first master control unit 18 may, for example, operate M basic circuit units 13 with a phase shift of 2π / M each. Operating a plurality of basic circuit units 13 with a phase shift can reduce ripples in the voltage across the superconducting coil 17. In the example shown in FIG. 1, the first master control unit 18 may, for example, operate three basic circuit units 13-1 to 13-3 with a phase shift of 2π / 3 each.

[0086] The first master control unit 18 may asynchronously control the plurality of basic circuit units 13. In this case, it is not necessary to synchronously control the basic circuit units 13, and therefore the operation of each basic circuit unit 13 can be easily controlled.

[0087] While charging superconducting coil 17, first master control unit 18 acquires the value of the current flowing through superconducting coil 17 from current sensor 15, which detects the current through superconducting coil 17. When first master control unit 18 determines that the current flowing through superconducting coil 17 has reached a predetermined threshold or greater, it terminates the charging process for superconducting coil 17. Furthermore, when first master control unit 18 determines that the current flowing through superconducting coil 17 has reached a predetermined threshold or greater, it controls low resistance switch 14 to turn on, shorting both ends of superconducting coil 17 and transitioning to a non-charging state.

[0088] The predetermined threshold may be the value of the current that needs to be passed through superconducting coil 17 in order to generate a predetermined DC magnetic field. The predetermined threshold may be, for example, about 900A.

[0089] When the low resistance switch 14 is turned on, a current flows through a closed loop that connects the low resistance switch 14, the current sensor 15, the second lead 16-1, the superconducting coil 17, and the second lead 16-2.

[0090] 6 is a diagram showing a conventional superconducting coil power supply device for a DC magnetic field that includes eight chopper circuits simply connected in parallel. When the superconducting coil power supply device for a DC magnetic field 1 is configured as in this conventional technology, the superconducting coil power supply device for a DC magnetic field 1 charges the superconducting coil 17 using eight chopper circuits 131 connected in parallel. Therefore, when charging the superconducting coil 17 so that a current of 300 A flows through the superconducting coil 17, the average current flowing through one chopper circuit 131 is 300 A / 8=37.5 A.

[0091] Because chopper circuits 131-1 to 131-8 operate in a time-division manner, power supply device 11 only needs to be able to supply an average current of about 37.5 A. Therefore, power supply device 11 can be a low-cost power supply device compared to a power supply device that can supply 300 A.

[0092] Furthermore, when charging superconducting coil 17 so that a current of 300 A flows through superconducting coil 17, first lead 12 only needs to be able to pass a current of about 37.5 A on average. Therefore, the cross-sectional area of ​​first lead 12 can be made smaller than that of a current lead that can pass 300 A. By making the cross-sectional area of ​​first lead 12 smaller, the amount of heat that enters cooling vessel 5 from the outside through first lead 12 can be reduced.

[0093] Furthermore, each chopper circuit 131 only needs to be able to pass an average current of about 37.5 A. Therefore, the chopper circuit 131 can be made smaller than a chopper circuit that can pass 300 A. This makes it easier to install the chopper circuit 131 inside the cooling vessel 5.

[0094] When a DC magnetic field superconducting coil power supply device equipped with such a chopper circuit 131 is made to handle large currents, for example, when a current of 900 A, which is three times the 300 A, can be made to flow, it is possible to either increase the capacity of the chopper circuit or increase the number of chopper circuits connected in parallel.

[0095] When increasing the capacity of a chopper circuit, it is possible to increase the current capacity by increasing the number of MOSFET elements in the chopper circuit connected in parallel. However, this method increases the number of MOSFETs connected in parallel as the current capacity increases, making it necessary to pay more attention to the current load balance of each MOSFET. In addition, the current capacity of the charging inductance must also be increased, requiring a charging inductance for each capacity. This requires a different hardware design for each current capacity, which is not practical.

[0096] Furthermore, if the number of parallel-connected chopper circuits included in the DC magnetic field superconducting coil power supply device 1 is simply increased, for example, from 8 to 24, it becomes necessary to increase the power supply voltage and charging inductance value by approximately three times. There are also limitations due to the withstand voltage performance of the switching elements of the chopper circuits. Furthermore, it is necessary to build a control logic for each current capacity, which is not practical.

[0097] In contrast to these methods, if a configuration is adopted that includes a plurality of basic circuit units 13, as in the DC magnetic field superconducting coil power supply device 1 according to the present disclosure, the configuration of the basic circuit unit 13 can be used as a basic form, and the equipment design and control system design can be reused. By performing time-sharing control of the chopper circuit 131 of the basic circuit unit 13, the current capacity can be easily increased without approximately tripling the power supply voltage and inductance value.

[0098] When the charging process of superconducting coil 17 is completed, control unit 19 may control first switches SA1 to SA8 and second switches SB1 to SB8 of chopper circuits 131-1 to 131-8 to be turned off.

[0099] Alternatively, when the charging process of superconducting coil 17 is completed, control unit 19 may control first switches SA1 to SA8 of chopper circuits 131-1 to 131-8 to be turned off, and control second switches SB1 to SB8 of chopper circuits 131-1 to 131-8 to be turned on.

[0100] When the second switches SB1 to SB8 of the chopper circuits 131-1 to 131-8 are controlled to be turned on, a series configuration of the inductor L1 and the second switch SB1, a series configuration of the inductor L2 and the second switch SB2, and a series configuration of the inductor L8 and the second switch SB8 are connected in parallel to the low-resistance switch 14, and the resistance value across the low-resistance switch 14 when the low-resistance switch 14 is turned on can be further reduced. For example, when the resistance value of the series-parallel configuration of the inductors L1 to L8 and the second switches SB1 to SB8 when they are on is small, such as when the inductors L1 to L8 are superconducting coils, the low-resistance switch 14 may be omitted.

[0101] The control unit 19 can adjust the duty ratio when operating the chopper circuit 131. Taking the chopper circuit 131-1 as an example, the duty ratio is the ratio of the time during which the first switch SA1 is on to the time during which the chopper circuit 131-1 is operating. That is, in FIG. 5, if the time from t1 to t3 during which the chopper circuit 131-1 is operating is defined as TA, and the time from t1 to t2 during which the first switch SA1 is on is defined as TB, the duty ratio is expressed as TB / TA.

[0102] Control unit 19 can adjust the duty ratio to adjust the charging capacity for superconducting coil 17. Control unit 19 can maximize the charging capacity for superconducting coil 17 by, for example, setting the duty ratio close to 100%.

[0103] (First Modification) 7 is a diagram showing the configuration of a DC magnetic field superconducting coil power supply device 1 according to a first modified example. Each of the multiple basic circuit units 13 may be provided with a power supply device 11, as shown in FIG. 7. In other words, the DC magnetic field superconducting coil power supply device 1 may be provided with multiple power supply devices 11.

[0104] Providing a power supply device 11 for each of the multiple basic circuit units 13 makes it possible to provide redundancy for the DC magnetic field superconducting coil power supply device 1. Furthermore, providing a power supply device 11 for each of the multiple basic circuit units 13 reduces the current input from each power supply device 11, making it possible to use a general-purpose DC power supply.

[0105] (Second Modification) Fig. 8 is a diagram showing the configuration of a superconducting coil power supply device for DC magnetic field 1 according to a second modification. As shown in Fig. 8, each of the plurality of basic circuit units 13 may include a low resistance switch 14. That is, the superconducting coil power supply device for DC magnetic field 1 may include a plurality of low resistance switches 14.

[0106] Providing a low-resistance switch 14 in each of the plurality of basic circuit units 13 makes it possible to provide redundancy to the DC magnetic field superconducting coil power supply device 1. Furthermore, providing a low-resistance switch 14 in each of the plurality of basic circuit units 13 eliminates the need to design a low-resistance switch section for each capacity.

[0107] (Third Modification) Fig. 9 is a diagram showing the configuration of a superconducting coil power supply device 1 for a DC magnetic field according to a third modification. As shown in Fig. 9, each of the plurality of basic circuit units 13 may include both a power supply device 11 and a low-resistance switch 14. In other words, the superconducting coil power supply device 1 for a DC magnetic field may include a plurality of both power supply devices 11 and low-resistance switches 14.

[0108] (Fourth Modification) FIG. 10 is a diagram showing the configuration of a DC magnetic field superconducting coil power supply device 1 according to a fourth modification. The plurality of basic circuit units 13 may further include a suppression reactor 20. The suppression reactor 20 connects the ground to which the second switches SB1 to SB8 are connected and the other end of the superconducting coil 17 via the second lead 16-2. By including the suppression reactor 20 in each basic circuit unit 13, most of the effects of current imbalances that occur between the chopper circuits 131 due to component variations and the like can be contained within each basic circuit unit 13. This reduces the difficulty of correcting imbalances in currents flowing through the chopper circuits 131 that occur as the number of chopper circuits 131 increases.

[0109] As shown in FIG. 10, one side of the suppression reactor 20 is connected to the power supply 11 via the ground of each chopper circuit 131 and the first lead 12-2, and the other side of the suppression reactor 20 is connected to the superconducting coil 17 via the low resistance switch 14 and the second lead 16-2.

[0110] (Fifth Modification) 11 is a diagram showing the configuration of a DC magnetic field superconducting coil power supply device 1 according to a fifth modified example. As shown in Fig. 11, one side of the suppression reactor 20 may be connected to each chopper circuit 131, and the other side of the suppression reactor 20 may be connected to the superconducting coil 17 via the low resistance switch 14, the current sensor 15, and the second lead 16-1.

[0111] (Sixth Modification) 12 is a diagram showing the configuration of a DC magnetic field superconducting coil power supply device 1 according to a sixth modification. When the low-resistance switch 14 is incorporated into a plurality of basic circuit units 13, one side of the suppression reactor 20 may be connected to the power supply device 11 via the ground of each chopper circuit 131, the low-resistance switch 14, and the first lead 12-2, and the other side of the suppression reactor 20 may be connected to the superconducting coil 17 via the second lead 16-2, as shown in FIG.

[0112] (Seventh Modification) 13 is a diagram showing the configuration of a DC magnetic field superconducting coil power supply device 1 according to a seventh modification. As shown in Fig. 13, one side of the suppression reactor 20 may be connected to each chopper circuit 131 and the low resistance switch 14, and the other side of the suppression reactor 20 may be connected to the superconducting coil 17 via the current sensor 15 and the second lead 16-1. Note that although Figs. 12 and 13 show an example in which the power supply device 11 and the first lead 12 are not included in the basic circuit unit 13, the power supply device 11 and the first lead 12 may be included in the basic circuit unit 13.

[0113] The operation of the DC magnetic field superconducting coil power supply device 1 will be described with reference to the flowchart shown in FIG.

[0114] First master control unit 18 controls low resistance switch 14 to be turned off (step S101). When DC magnetic field superconducting coil power supply device 1 includes multiple low resistance switches 14, the on / off timing of each low resistance switch is the same.

[0115] 5, the first master control unit 18 charges the superconducting coil 17 by controlling the first switches SA1 to SA8 and the second switches SB1 to SB8 of the chopper circuits 131-1 to 131-8 (step S102). When the basic circuit units 13 are to be operated in the same phase, the first master control unit 18 controls the basic circuit units 13 via the control unit 19 to operate in the same phase in step S102. When the basic circuit units 13 are to be operated with a phase shift of 2π / M, since there are three basic circuit units 13 in this example, the first master control unit 18 controls the basic circuit unit 13-1 via the control unit 19 to operate in a phase of 0°, the basic circuit unit 13-2 at 120°, and the basic circuit unit 13-3 at 240°.

[0116] While superconducting coil 17 is being charged, first master control unit 18 acquires from current sensor 15 the value of the current flowing through superconducting coil 17 detected by current sensor 15 (step S103).

[0117] First master control unit 18 determines whether the current flowing through superconducting coil 17 is equal to or greater than a predetermined threshold value (step S104).

[0118] If the current flowing through superconducting coil 17 is less than the predetermined threshold value (No in step S104), first master control unit 18 returns to step S103.

[0119] If the current flowing through superconducting coil 17 is equal to or greater than the predetermined threshold value (Yes in step S104), first master control unit 18 stops charging superconducting coil 17 (step S105). After stopping charging, first master control unit 18 controls low-resistance switch 14 to turn on (step S106).

[0120] Although an example has been described in which an independent first master control unit 18 controls the control unit 19, the control method of the DC magnetic field superconducting coil power supply device 1 according to the present disclosure is not limited to this. For example, any one of the control units 19 included in the multiple basic circuit units 13 may function as a second master control unit that controls the other control units 19.

[0121] The present disclosure is not limited to the above-described embodiments. For example, multiple blocks shown in the block diagrams may be integrated, or a single block may be divided. Other modifications may be made without departing from the spirit of the present disclosure.

[0122] For example, in the above embodiment, an example has been described in which basic circuit units 13 each including eight chopper circuits 131 connected in parallel are connected in parallel, but the number of basic circuit units 13 connected in parallel may be any number equal to or greater than 2. Similarly, the number of chopper circuits 131 included in the basic circuit unit 13 may also be any number equal to or greater than 2.

[0123] In Figures 1 and 7 to 13, the first master control unit 18 and the control unit 19 are depicted as being located inside the cooling container 5, but the first master control unit 18 and the control unit 19 may also be located outside the cooling container. [Industrial Applicability]

[0124] The DC magnetic field superconducting coil power supply device of the present disclosure is suitable for applications in which a DC magnetic field is generated using a superconducting coil. [Explanation of symbols]

[0125] 1. DC magnetic field superconducting coil power supply unit 5 Cooling container 11 Power supply 12 First Lead 13 Basic circuit unit 131 Chopper Circuit 14 Low resistance switch 15 Current Sensor 16 Second Lead 17 Superconducting coil 18 First master control unit 19 Control Unit 20 Suppression reactor L1~L8 inductors SA1~SA8 First switch SB1~SB8 Second switch

Claims

1. a superconducting coil; a power supply device capable of supplying DC voltage; a plurality of basic circuit units; The basic circuit unit comprises: a plurality of chopper circuits connected in parallel between one end of the power supply device and one end of the superconducting coil; a control unit that controls the plurality of chopper circuits, The control unit operates the plurality of chopper circuits in a time-division manner when charging the superconducting coil.

2. 2. The DC magnetic field superconducting coil power supply device according to claim 1, The control unit operates each chopper circuit of each basic circuit unit once during one cycle.

3. 2. The DC magnetic field superconducting coil power supply device according to claim 1, The DC magnetic field superconducting coil power supply device further comprises a low resistance switch capable of short-circuiting both ends of the superconducting coil.

4. 2. The DC magnetic field superconducting coil power supply device according to claim 1, a first master control unit that controls the control unit; The first master control unit operates the plurality of basic circuit units without phase control.

5. 2. The DC magnetic field superconducting coil power supply device according to claim 1, a first master control unit that controls the control unit; The first master control unit operates the plurality of basic circuit units in the same phase.

6. 2. The DC magnetic field superconducting coil power supply device according to claim 1, a first master control unit that controls the control unit; The first master control unit operates the plurality of basic circuit units with a phase shift of 2π / M when the number of the plurality of basic circuit units is M.

7. 2. The DC magnetic field superconducting coil power supply device according to claim 1, Any one of the control units is a second master control unit that also controls the other control units, The second master control unit operates the plurality of basic circuit units without phase control.

8. 2. The DC magnetic field superconducting coil power supply device according to claim 1, Any one of the control units is a second master control unit that also controls the other control units, The second master control unit operates the plurality of basic circuit units in the same phase.

9. 2. The DC magnetic field superconducting coil power supply device according to claim 1, Any one of the control units is a second master control unit that also controls the other control units, The second master control unit operates the plurality of basic circuit units with a phase shift of 2π / M when the number of the plurality of basic circuit units is M.

10. 2. The DC magnetic field superconducting coil power supply device according to claim 1, The chopper circuit is a first switch and an inductor that connect one end of the power supply device and one end of the superconducting coil in series; a second switch connecting a node between the first switch and the inductor to ground;

11. 11. The DC magnetic field superconducting coil power supply device according to claim 10, The DC magnetic field superconducting coil power supply device, wherein the basic circuit unit further includes a suppression reactor connected between the ground and the other end of the superconducting coil.

12. 11. The DC magnetic field superconducting coil power supply device according to claim 10, The basic circuit unit further includes a suppression reactor connected between the plurality of chopper circuits and one end of the superconducting coil.

13. 2. The DC magnetic field superconducting coil power supply device according to claim 1, a plurality of the power supply devices; The basic circuit unit comprises: A DC magnetic field superconducting coil power supply device further comprising one of the plurality of power supply devices.

14. 14. The DC magnetic field superconducting coil power supply device according to claim 13, a plurality of low-resistance switches capable of short-circuiting both ends of the superconducting coil; The basic circuit unit comprises: The DC magnetic field superconducting coil power supply device further comprises one of the plurality of low resistance switches.

15. 15. The DC magnetic field superconducting coil power supply device according to claim 13 or 14, The chopper circuit is a first switch and an inductor that connect one end of the power supply device and one end of the superconducting coil in series; a second switch connecting a node between the first switch and the inductor to ground;

16. 16. The DC magnetic field superconducting coil power supply device according to claim 15, The DC magnetic field superconducting coil power supply device, wherein the basic circuit unit further includes a suppression reactor connected between the ground and the other end of the superconducting coil.

17. 16. The DC magnetic field superconducting coil power supply device according to claim 15, The basic circuit unit further includes a suppression reactor connected between the plurality of chopper circuits and one end of the superconducting coil.

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