Time-variable strong magnetic field generator

Abstract

To provide a time waveform variable strong magnetic field generation device with a simple circuit configuration, which is capable of temporarily supplying a large current even with a relatively small power supply contract with a power supply amount of several kW, such as a commercial low-voltage power supply.SOLUTION: A time waveform variable strong magnetic field generation device includes an electromagnet 10 that generates a strong magnetic field, a power supply device 30 capable of supplying the electromagnet 10 while changing a supply current in a predetermined pattern over time. Preferably, the power supply 30 may include a power storage unit 32 having at least one of a storage battery and a large-capacity capacitor, a current waveform setting unit 70 that sets a current waveform to be supplied to the electromagnet 10, and a current control unit 60 that supplies a current for driving the electromagnet 10 from the power storage unit 32 in response to the waveform control signal from the current waveform setting unit 70.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a time waveform variable strong magnetic field generating device that can supply a temporary large current even under a relatively small-scale power supply contract with a supply capacity of about several kW, such as a commercial low-voltage power source. [Background technology]

[0002] Magnets can be broadly classified into permanent magnets and electromagnets. However, for applications that require the generation of strong magnetic fields (high magnetic fields) of 1 Tesla or more that cannot be easily achieved with permanent magnets, electromagnet systems are used, which generate a magnetic field by supplying a direct current to a coil. For example, Bitter-type electromagnets are used when a very strong magnetic field is required (see Patent Documents 1 and 2, and Non-Patent Documents 1 and 2). The iron cores used in conventional electromagnets are saturated and are limited to a magnetic field of about 2 Tesla. Superconducting electromagnets can generate stronger magnetic fields, and the theoretical limit is higher, but they are limited to a magnetic field of 10 to 20 Tesla due to magnetic flux creep. To obtain a stronger magnetic field, resistive solenoid electromagnets such as Bitter-type electromagnets are used. The disadvantages of resistive solenoid electromagnets are that they require a very large driving current and emit a large amount of heat.

[0003] What electromagnets have in common is that they generate a magnetic field at their center by passing electricity through a wound conductor called a coil. When a magnetic field is generated by passing a current through a coil, the amount of current passed is simply proportional to the magnitude and time waveform of the generated magnetic field. Therefore, to arbitrarily change the magnetic field output, all that is needed is to control the "magnitude" and "time change" of the current passed through the coil.

[0004] Conventional strong magnetic field magnets have focused on generating a magnetic field with high stability over a long period of time, so the primary method has been to generate a "steady strong magnetic field" with little change in current over time (drift). However, as the amount of current increases, problems such as the generation of stress (Maxwell stress) that significantly deforms the coil outward and heat generation due to coil resistance become more pronounced, so the current must be limited to an upper limit that does not damage the magnet system itself, meaning there is a limit to the maximum magnetic field that can be generated. Therefore, if you want to generate a magnetic field even stronger than this, you need to use a method to generate a momentary strong magnetic field (pulsed strong magnetic field) by instantaneously passing a large amount of electrical energy stored in a capacitor or other device through the coil.

[0005] Steady-state strong magnetic field magnets include superconducting magnets that use superconducting wires with zero electrical resistance, and normal conducting magnets that use metallic materials with electrical resistance, while pulsed strong magnetic field magnets include wound magnets that use high-strength, highly conductive wires, and electromagnetic concentration magnets that are designed to be destroyed. The current rough upper limits of the magnetic field generated by steady-state high-field magnets and pulsed high-field magnets are as follows: Steady-state strong magnetic field magnets include superconducting magnets, normal conducting magnets, and hybrid magnets, with the approximate upper limit of the magnetic field they can generate being approximately 20 Tesla, 30 Tesla, and 50 Tesla, respectively. Pulsed strong magnetic field magnets include wound-type non-destructive pulse magnets, single-turn coil-type pulse magnets, and electromagnetic concentration-type pulse magnets, with the approximate upper limit of the magnetic field they can generate and their generation times being approximately 100 Tesla (approximately 100 milliseconds), 200 Tesla (approximately 10 microseconds), and 1,000 Tesla (approximately 5 microseconds), respectively.

[0006] The advantage of a constant magnetic field is that extremely accurate measurements are possible by keeping the magnetic field constant or by slowly changing it. However, there are some disadvantages, such as an upper limit to the magnetic field, the need for expensive cryogens (liquid helium), large-scale equipment, and the need for very large amounts of electricity. On the other hand, although pulsed magnetic fields can generate strong magnetic fields with small power that are impossible with constant magnetic field devices, the magnetic field is generated and changes in an extremely short time of about 10 microseconds to 100 milliseconds, making it less suitable for high-precision experiments compared to constant magnetic fields. In addition, the magnetic field waveform is a trigonometric function-like waveform determined by circuits including coils and capacitors, and the waveform itself cannot be easily changed, which is a disadvantage. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent No. 6,925,316 [Patent Document 2] Japanese Patent Publication No. 61-58473 [Non-patent literature]

[0008] [Non-Patent Document 1] LG Rubin et.al. Translated by Yoshitake Kido, "Francis Pitter National Magnet Laboratory", Journal of the Physical Society of Japan, Vol. 37, pp. 824-829 (1982) [Non-Patent Document 2] Shigeto Miura et al., "Development of Large High-Strength Silver-Copper Sheets for High-Field Pitter Coils," Journal of the Japan Institute of Metals, Vol. 63, pp. 1290-1294 (1999) Summary of the Invention [Problem to be solved by the invention]

[0009] Against this background, steady-state high-field magnets and pulsed high-field magnets are used complementarily in materials research and other fields to measure various physical properties (electrical, optical, and magnetic properties) under strong magnetic fields, taking advantage of the characteristics of each magnet. Large, steady-state, strong magnetic field magnets are capable of stably generating a constant magnetic field for long periods of time, but the generation itself takes time (about an hour), and the same order of time is required to change the magnetic field waveform. Therefore, while highly accurate experiments are possible, there are disadvantages such as the extremely long time required to measure a large number of samples, there being a certain upper limit to the generation of a strong magnetic field, and the larger the magnet, the more expensive it is to operate and maintain. Therefore, it is special equipment that is only available at research graduate universities and national research institutes of natural sciences.

[0010] Conversely, a pulsed strong magnetic field is extremely energy efficient because it generates a strong magnetic field in a short time by instantaneously discharging the energy stored in a large capacitor. However, it has some disadvantages, such as the fact that the magnetic field generation time is very short, the magnetic field waveform can only be controlled to a fixed shape, and the data accuracy is, in principle, lower than that of measurements in a steady magnetic field. For this reason, the electromagnets most commonly used in materials research and other fields are commercially available superconducting magnets with a magnetic field strength of around 10 Tesla. Although superconducting magnets do not require a large amount of power to generate the magnetic field due to their characteristics, they have the same problems as large, constant, strong magnetic field magnets, such as the fact that they always require an expensive cryogen called liquid helium, and that although they are in principle strong at generating a constant magnetic field, it is difficult to change the magnetic field significantly in a short period of time, which means that measurements take a long time. [Means for solving the problem]

[0011] By the way, from the viewpoints of (1) maximum generated magnetic field, (2) magnetic field maintenance time, and (3) generated magnetic field waveform, development has been proceeding in the direction of satisfying the maximum generated magnetic field and magnetic field maintenance time. However, in the field of strong magnetic field generation, the generated magnetic field waveform has not been given attention compared to the viewpoints of the maximum generated magnetic field and the magnetic field maintenance time. We thought that it would be possible to realize a time waveform variable strong magnetic field generator that is highly efficient and comparable in accuracy to conventional devices and enables measurement in a magnetic field at low cost by arbitrarily changing the magnetic field value within the magnetic field generation time of the generated magnetic field waveform, and we have completed this invention. In particular, in conventional magnetic field generating devices capable of varying the time waveform, a high-frequency current is typically passed through the sensor while a DC bias voltage is applied to modulate the high-frequency signal, necessitating the use of a demodulator to obtain a signal for measuring the magnetic field, which results in a complex circuit configuration and makes it difficult, in principle, to generate the strong magnetic field described in the present invention.

[0012] The present invention solves the problems of the steady magnetic field and pulsed magnetic field generating systems described above, and aims to provide a strong magnetic field generating device that can supply a temporary large current even with a relatively small power supply contract with a supply power of about a few kW, such as a commercial low-voltage power source, and that has a simple circuit configuration without using a demodulator, and in which the time waveform of the generated magnetic field can be changed.

[0013] [1] A time-waveform variable strong magnetic field generating device of the present invention, as shown in, for example, Figures 1 and 3, comprises an electromagnet 10 for generating a strong magnetic field, and a power supply unit 30 capable of supplying a current to the electromagnet 10 while varying the current over time in a predetermined pattern.

[0014] [2] In the time waveform variable strong magnetic field generator of the present invention, the power supply 30 preferably includes a power storage unit 32 having at least one of a storage battery or a large-capacity capacitor, a current waveform setting unit 70 which sets the current waveform to be supplied to the electromagnet 10, and a current control unit 60 which supplies a current to drive the electromagnet 10 from the power storage unit 32 in response to a waveform control signal from the current waveform setting unit 70. [3] In the time waveform variable strong magnetic field generating apparatus of the present invention, the large-capacity capacitor is preferably an electric double layer capacitor, an oil-immersed charge / discharge capacitor, or a chemical capacitor. [4] In the time waveform variable strong magnetic field generating apparatus of the present invention, preferably, the current supplied to the electromagnet 10 by the current control unit 60 is a maximum of 30,000 amperes, and the applied voltage is a maximum of 400 volts. [5] In the time waveform variable strong magnetic field generating device of the present invention, the power supply device 30 is preferably further connected to a commercial power supply 31 for charging. [6] In the time waveform variable strong magnetic field generator of the present invention, preferably, the current waveform setting unit 70 generates a waveform control signal instructing a step-like waveform, and the time during which the magnetic field value generated in the electromagnet 10 by the step-like waveform continues to be a constant value is the time required to measure the magnetic properties of the object. [7] In the time waveform variable strong magnetic field generating device of the present invention, the time required to measure the magnetic properties of an object is preferably such that a measurement value with the same high accuracy as that obtained by measuring a steady magnetic field can be obtained. [8] In the time waveform variable strong magnetic field generating apparatus of the present invention, the electromagnet 10 is preferably a Bitter type electromagnet or a wound type electromagnet. [9] In the time waveform variable strong magnetic field generator of the present invention, the strong magnetic field is preferably 1 Tesla or more and 70 Tesla or less. Preferably, the strong magnetic field is more than 20 Tesla and 70 Tesla or less, which is a higher value than the magnetic field that can be generated by a superconducting magnet alone. Effect of the Invention

[0015] In the case of the time waveform variable strong magnetic field generator of the present invention, the waveform of the generated magnetic field can be controlled in proportion to the input signal from an external waveform generator, and the duration of the magnetic field generation can be set to the time required to measure the magnetic properties of the target object (for example, in the range of 0.1 seconds to several minutes). The current waveform setting unit can, for example, create a stepped waveform and use it to perform sufficient measurements during the time when the magnetic field value is at a certain step, making it possible to perform measurements in a short period of time with the same level of accuracy as steady-state magnetic field measurements. More preferably, when a step-like changing magnetic field is generated, it becomes possible to perform measurements in successively different magnetic fields (magnetic field change measurement), and the total measurement time can be significantly shortened compared to when a normal steady magnetic field is used. More preferably, by using a storage battery or a small, large-capacity capacitor as the power storage unit, the time waveform variable strong magnetic field generator of the present invention can be made mobile, and a low-voltage commercial power source can be used that requires a smaller contracted ampere number than a normal steady-state magnetic field generator, which requires liquid helium or a large amount of power as a commercial power source for charging. This allows the power supply contract required for magnetic field generation to be low-cost, and reduces maintenance costs. [Brief description of the drawings]

[0016] [Figure 1] 1 is a functional block diagram illustrating a power supply device using a storage battery according to an embodiment of the present invention, and a control system for controlling the power supply device. [Diagram 2] FIG. 2 is a waveform diagram of an output current of the device shown in FIG. [Diagram 3] FIG. 1 is a diagram showing the configuration of a Bitter magnet according to one embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing the configuration of a circular metal plate which is a component of the Bitter magnet shown in FIG. [Diagram 5] 1 is a waveform diagram showing various generated magnetic field waveforms according to one embodiment of the present invention. [Figure 6] FIG. 11 is a waveform diagram of a step-like magnetic field when the maximum current value is changed, showing one embodiment of the present invention. [Figure 7] FIG. 2 is a waveform diagram illustrating generation of a stepped magnetic field repeated five times according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The present invention will now be described with reference to the drawings. In the time waveform variable strong magnetic field generator of the present invention, for example, a Bitter type electromagnet or a wound type electromagnet is used as the electromagnet 10 capable of handling the large current for generating a strong magnetic field. Here, the strong magnetic field is preferably 1 Tesla or more and 70 Tesla or less, and more preferably, more than 20 Tesla and 70 Tesla or less, and is a value higher than the magnetic field that can be generated by a superconducting magnet alone. The large current is preferably, for example, a maximum of 30,000 amperes, and the applied voltage is preferably a maximum of 400 volts.

[0018] It is preferable that the power supply device 30 can supply a current to the electromagnet 10 while changing the supply current over time in a predetermined pattern. For this purpose, it is preferable that the power supply device 30 uses a storage battery or a small, large-capacity capacitor, and can quickly control and adjust the amount of current, for example, a maximum applied current of 30,000 amperes and a maximum applied voltage of 400 volts from the storage portion in response to an external waveform input from the signal generator 70 as a current waveform setting unit. A storage battery is a device that converts electrical energy into chemical energy, stores it, and can extract electricity as needed, and can be used repeatedly by recharging. They are also called batteries or secondary batteries, and there are various types, such as lead-acid batteries, nickel-metal hydride batteries, NAS (sodium-sulfur) batteries, and lithium-ion batteries. The large-capacity capacitor may be an electric double-layer capacitor, an oil-filled charge-discharge capacitor, or a chemical capacitor. An electric double-layer capacitor has a capacitor structure with opposing electrodes using an electric double layer as a dielectric, and has a capacitance of, for example, several tens of F (farads). Here, the electric double layer refers to a state in which electrons or holes attract each other and are aligned due to charging, which occurs spontaneously between a solid and a liquid. An oil-filled charge-discharge capacitor uses a paper processed from wood pulp impregnated with insulating oil as a dielectric. Because of its simple structure, an oil-filled charge-discharge capacitor has the drawback that it becomes larger in size in order to increase the capacitance, but it has excellent voltage resistance. A chemical capacitor is also called an aluminum electrolytic capacitor, and uses an oxide film (aluminum oxide) formed on the surface of an aluminum electrode (usually aluminum foil) as a dielectric. A chemical capacitor can obtain a large capacity because the dielectric layer is very thin. By combining the electromagnet 10 with the power supply unit 30, a magnetic field generating system can be realized that allows the generation of any magnetic field duration and any magnetic field waveform.

[0019] FIG. 1 is a functional block diagram of a power supply device using a storage battery according to an embodiment of the present invention, and also shows a control system for controlling the power supply device. In the diagram, a power supply device 30 of the present invention includes a charging commercial power source 31, a storage battery 32, a control block 40 for large currents, a current output circuit 50, and a feedback control block 60. The charging commercial power source 31 is a power supply system for charging the storage battery 32, and a relatively small-scale power supply contract with a supply power of about several kW, such as a commercial low-voltage power source, is sufficient, but a high-voltage power supply system used in a normal steady-state magnetic field generator that requires liquid helium or large power may also be used. The high-voltage power supply system has a supply voltage of, for example, 6.6 kV and can handle a supply power of about several MW. The power supply device 30 includes a smoothing capacitor 33, a control circuit power supply 34, and an operation and monitoring circuit 36 ​​in addition to the storage battery 32. The storage battery 32 supplies DC power and has a rated voltage of, for example, 16V to 400V and a rated current of, for example, 1 to 30kA. The smoothing capacitor 33 smoothes the current and voltage supplied by the storage battery 32 and is connected in parallel to a large current compatible control block 40 to the positive and negative terminals of the storage battery 32. The control circuit power supply 34 provides power for the operation and monitoring circuit 36 ​​from a commercial power source. The operation and monitoring circuit 36 ​​monitors the terminal voltage and supply current of the storage battery 32 and provides input voltage information to the PWM circuit 66. The operation and monitoring circuit 36 ​​can also function as an auxiliary power supply and may be configured to supply power for storage to the storage battery 32. By providing the storage battery 32, even if charging is performed using a commercial power source 31 for charging under a relatively small-scale power supply contract with a supply capacity of several kW, such as a commercial low-voltage power source, it becomes possible to temporarily supply a large current from the storage battery 32. This eliminates the need for a power supply contract of several MW as in the case of factories and large commercial facilities, and allows the contracted ampere number to be reduced, resulting in lower electricity bills.

[0020] The large current compatible control block 40 has a field effect transistor (FET) 42, a drive circuit 44, a smoothing capacitor 46, a diode 47, and an inductor Lf 48. The field effect transistor 42 receives a PWM control signal from a pulse width modulation circuit 66 at its gate terminal to perform on / off control of the drain current between its drain terminal and source terminal. The smoothing capacitor 46 and the diode 47 are connected to the positive and negative terminals of the storage battery 32 with the field effect transistor 42 in between. The inductor Lf 48 is inserted between the field effect transistor 42 and the current output circuit 50. The current output circuit 50 has a capacitor Cf 52 and a common mode coil CM, and outputs an output current for exciting the Bitter-type magnet 10 between output terminals P and N.

[0021] The feedback control block 60 has the output current detection transformer 54, a buffer amplifier 58, an error amplifier 62, a duty cycle limiting circuit 64, and a pulse width modulation circuit (PWM) 66. The buffer amplifier 58 receives the detection signal of the output current detection transformer 54 and is used, for example, to monitor the output current. The error amplifier 62 compares the output current detection transformer 54 with a pattern signal of the duty cycle limiting circuit 64 and sends the result to the pulse width modulation circuit 66. The duty cycle limiting circuit 64 limits the amount of current change per unit time (dI / dt), and also limits the upper limit of the duty ratio of the pulse width modulation circuit 66 when the error signal of the error amplifier 62 is large, thereby preventing the Bitter-type magnet 10 from being damaged by an excessive current. The signal generator 70 outputs a pattern signal to the duty cycle limiting circuit 64, which indicates the drive current waveform to be supplied to the Bitter-type magnet 10. The personal computer 72 is equipped with software that makes it easy to indicate the drive current waveform pattern to the signal generator 70, and a general-purpose computer device is used.

[0022] In the device configured in this manner, the signal generator 70 is controlled from the personal computer 72PC, and a voltage profile identical to the waveform of the magnetic field to be generated is sent to the duty cycle limiting circuit 64. Figure 2 is a waveform diagram of the output current of the device shown in Figure 1. In the case of an electric double-layer capacitor or an electromagnet, there is a limit to the range of allowable current increment per unit time, so the output current waveform diagram is specified within this limit.

[0023] In the duty cycle limiting circuit 64, the DC current from the storage battery 32 is controlled in accordance with the pattern signal sent from the signal generator 70, and a current flows through the circular metal plate 12 of the Bitter coil connected to the output terminals P and N of the current output circuit 50, generating a magnetic field. In addition, when generating a pulsed magnetic field, it is possible to generate a magnetic field of 30 Tesla or more for 1 millisecond using electrical energy stored in a high-capacity capacitor system. Therefore, by using this Bitter coil as is, it is sufficient to withstand a strong magnetic field of about 30 Tesla. Heat generated by the coil is quickly cooled by circulating pure water inside the magnet using a small circulating cooler.

[0024] FIG. 3 is a diagram showing the configuration of a Bitter-type electromagnet, showing one embodiment of the present invention. In the figure, the Bitter-type magnet 10 has a circular metal plate 12, an insulating plate 14, a flange 16, and a clamping rod 18. The Bitter-type magnet is not a coiled wire, but is constructed by stacking circular conductive metal plates and insulating spacers in a spiral shape. Current flows in a spiral shape between the circular metal plates. The purpose of the laminated circular metal plate using a copper-silver alloy is to withstand the enormous mechanical pressure caused by the Lorentz force due to the magnetic field acting on the moving charges in the circular metal plate, which increases in proportion to the square of the magnetic field strength. In addition, water is circulated as a coolant through holes in the circular metal plate to dissipate the enormous amount of heat generated in the circular metal plate by resistance heating due to the large current flowing through the circular metal plate. The amount of heat dissipated increases in proportion to the square of the magnetic field strength.

[0025] The circular metal plate 12 is a roughly circular plate made by punching copper or a strong copper alloy, and has slits 122, notched holes 124 for fastening rods, a hole 126 for cooling water, and a central hole 128. The circular metal plate 12 uses a Bitter coil for generating a strong magnetic field, which uses a copper-silver alloy, a high-strength, highly conductive material. The applicant uses this Bitter coil for both generating a steady strong magnetic field and a pulsed magnetic field, and has a track record of generating a magnetic field of up to about 30 Tesla by supplying 15 megawatts of power to generate a steady strong magnetic field. The slits 122 rotate between adjacent layers by an angle corresponding to the notch angle of the wedge-shaped notch 142; for example, in the case of 45 degrees, one rotation takes eight sheets, and in the case of 30 degrees, one rotation takes twelve sheets. The insulating plate 14 is, for example, a plate made of polyimide resin, and is formed with a wedge-shaped cutout portion 142, a notched hole 144 for a tightening rod, a hole 146 for cooling water, and a central hole 148. The wedge-shaped cutout portion 142 is formed by cutting a part of the circumferential surface at a predetermined angle, for example, about 30 degrees to 45 degrees, from the axial direction into the circumferential portion. The laminated circular metal plates 12 form one turn of the coil by establishing electrical continuity with adjacent circular metal plates 12 at the cutout portion 146 of the insulating plate 14 as a stacked coil, and by establishing insulation with adjacent circular metal plates 12 at the insulating plate 14 excluding the cutout portion 146.

[0026] The flanges 16 are provided at both axial ends of the Bitter-type magnet 10, and are made of, for example, FRP disks, and have the rigidity to support the fastening force of the fastening rods 18. The fastening rods 18 fasten the overlapping coil laminate of the circular metal plate 12 and the insulating plate 14, and for example, eight of them are provided at equal intervals in the axial direction. The fastening rods 18 are attached to the corresponding fastening rod cutout holes 124, 144 of each layer, and since they are attached along the peripheral surface of the circular metal plate 12, a fastening ring 182 is provided in a position close to the flange 16 side to fasten and hold the fastening rods.

[0027] The high magnetic field introduction path 20 communicates with the central hole 128 of the circular metal plate 12 and the central hole 148 of the insulating plate 14, and is an introduction path for sending an object to be observed into the high magnetic field space generated by the Bitter-type magnet 10. The electrodes 22 have electric wire connection terminals provided on the surfaces of the flanges 16 at both ends, and are connected to both side ends of the stacked circular metal plates 12. The cooling water supply pipe 24 is a pipe that supplies cooling water to the cooling water holes 126 of the corresponding circular metal plates 12 of each layer and the cooling water holes 146 of the insulating plates 14, and has cooling water connection ports on the surfaces of the flanges 16 at both ends. 6 It is advisable to use deionized distilled water with a viscosity of Ω·cm. The cooling water supplied from the cooling water supply pipe 24 exchanges heat with the heat generated by the generation of a high magnetic field in the Bitter-type magnet 10.

[0028] Figure 5 is a waveform diagram showing various generated magnetic field waveforms according to one embodiment of the present invention. Figure 5(A) shows a magnetic field actually generated by inputting a trigonometric function waveform, and Figure 5(B) shows a stepped magnetic field. The entire generation time of the stepped magnetic field is about 2 seconds, and the constant portion of the stepped portion is about 0.2 seconds.

[0029] Figure 6 shows the waveform of a stepped magnetic field generated by changing the current. It can be seen that the magnetic field is generated according to the maximum current.

[0030] Figure 7 shows the measurement results of repeatedly generating a stepped magnetic field, which was repeated five times in this experiment. In principle, this can be repeated until the battery runs out of energy. This type of repeated magnetic field is the same as turning a magnetic field on and off, and could be used for magnetic refrigeration, etc.

[0031] In the above embodiment, the electromagnet for generating a strong magnetic field is a Bitter-type electromagnet, but a wound-type electromagnet may be used. Also, in the above embodiment, the power storage unit is a storage battery, but a large-capacity capacitor may be used. [Industrial Applicability]

[0032] The variable time waveform strong magnetic field generating device of the present invention enables on / off control of the magnetic field at a high repetition frequency, which has a great ripple effect such as enabling application to magnetic refrigeration devices. In addition, the time waveform variable strong magnetic field generator of the present invention may be applicable to commercial and military applications such as non-lethal weapons (action restraint systems) for non-lethal standoff weapons (air-to-ground missiles launched from outside the effective range of enemy air defense systems), high magnetic field insert coils for NMR above 1 GHz, laboratory-scale research magnets, magnetic bearings for flywheel energy storage and magnetic levitation, high-power motors / generators, transformers, and inductive interference current limiters. [Explanation of symbols]

[0033] 10: Bitter type electromagnet 12:Circular metal plate 122: Slit 124: Notched hole for tightening rod 126: Cooling water hole 128: Central hole 14: Insulating plate 142: Wedge-shaped cutout 144: Notched hole for tightening rod 146: Cooling water hole 148: Central hole 16: Flange 18: Clamping rod 182: Fastening ring 20: High magnetic field introduction path 22: Electrode 24: Cooling water supply pipe 30: Power supply 31: Commercial power supply for charging 32: Battery 40: Control block for large current 50: Current output circuit 60: Feedback control block 70: Signal generator (signal waveform setting section) 72: Personal computer (PC)

Claims

1. The present invention comprises an electromagnet for generating a strong magnetic field, and a power supply device capable of supplying a current to the electromagnet while changing the current over time in a predetermined pattern, The power supply device is a power storage unit having at least one of a storage battery and a large-capacity capacitor; a power supply unit that supplies charging power to the power storage unit; a current waveform setting unit that sets a current waveform to be supplied to the electromagnet; a current control unit that supplies a current for driving the electromagnet from the power storage unit in response to a waveform control signal from the current waveform setting unit; With A time waveform variable strong magnetic field generating device, wherein the current supplied to the electromagnet by the current control unit is a maximum of 30,000 amperes, and the applied voltage is a maximum of 400 volts.

2. The present invention comprises an electromagnet for generating a strong magnetic field, and a power supply device capable of supplying a current to the electromagnet while changing the current over time in a predetermined pattern, The power supply device is a power storage unit having at least one of a storage battery and a large-capacity capacitor; a power supply unit that supplies charging power to the power storage unit; a current waveform setting unit that sets a current waveform to be supplied to the electromagnet; a current control unit that supplies a current for driving the electromagnet from the power storage unit in response to a waveform control signal from the current waveform setting unit; With The current waveform setting unit generates a waveform control signal instructing a stepped waveform, A time-variable strong magnetic field generator, wherein the time during which the magnetic field value generated in the electromagnet by the stepped waveform remains constant is the time required to measure the magnetic properties of an object.

3. 3. The apparatus for generating a strong magnetic field with variable time waveform according to claim 1, wherein the large-capacity capacitor is an electric double-layer capacitor, an oil-filled charge-discharge capacitor, or a chemical capacitor.

4. 4. The time waveform variable strong magnetic field generating apparatus according to claim 1, wherein the power supply device is further connected to a commercial power supply for charging.

5. The current waveform setting unit generates a waveform control signal instructing a stepped waveform, 2. The time waveform variable strong magnetic field generator according to claim 1, wherein the time during which the magnetic field value generated in the electromagnet by the step-like waveform remains constant is a time required to measure the magnetic properties of an object.

6. 6. The apparatus for generating a strong magnetic field with variable time waveform according to claim 2 or 5, wherein the time required for measuring the magnetic properties of an object is such that a measurement value with high accuracy equivalent to that obtained by measuring a steady magnetic field can be obtained.

7. 7. The apparatus for generating a strong magnetic field with variable time waveform according to claim 1, wherein the electromagnet is a Bitter-type electromagnet or a wound-type electromagnet.

8. 8. The apparatus for generating a strong magnetic field with variable time waveform according to claim 1, wherein the strong magnetic field is 1 Tesla or more and 70 Tesla or less.

Images